Isoprenoid quinones resolve the stratification of microbial redox processes in a biogeochemical continuum from the photic zone to deep anoxic sediments of the Black Sea.

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Becker, Kevin W; Elling, Felix J; Schröder, Jan M; Lipp, Julius S; Goldhammer, Tobias; Zabel, Matthias; Elvert, Marcus; Overmann, Jörg; Hinrichs, Kai-Uwe

2018-03-09

The stratified water column of the Black Sea serves as a model ecosystem for studying the interactions of microorganisms with major biogeochemical cycles. Here we provide detailed analysis of isoprenoid quinones to study microbial redox processes in the ocean. In a continuum from the photic zone through the chemocline into deep anoxic sediments of the southern Black Sea, diagnostic quinones and inorganic geochemical parameters indicate niche segregation between redox processes and corresponding shifts in microbial community composition. Quinones specific for oxygenic photosynthesis and aerobic respiration dominate oxic waters, while quinones associated with thaumarchaeal ammonia-oxidation and bacterial methanotrophy, respectively, dominate a narrow interval in suboxic waters. Quinone distributions indicate highest metabolic diversity within the anoxic zone, with anoxygenic photosynthesis being a major process in its photic layer. In the dark anoxic layer, quinone profiles indicate occurrence of bacterial sulfur and nitrogen cycling, archaeal methanogenesis, and archaeal methanotrophy. Multiple novel ubiquinone isomers, possibly originating from unidentified intra-aerobic anaerobes, occur in this zone. The respiration modes found in the anoxic zone continue into shallow subsurface sediments, but quinone abundances rapidly decrease within the upper 50 cm below sea floor, reflecting the transition to lower energy availability. In the deep subseafloor sediments, quinone distributions and geochemical profiles indicate archaeal methanogenesis/methanotrophy and potentially bacterial fermentative metabolisms. We observed that sedimentary quinone distributions track lithology, which supports prior hypotheses that deep biosphere community composition and metabolisms are determined by environmental conditions during sediment deposition. Importance Microorganisms play crucial roles in global biogeochemical cycles. Yet, we have only a fragmentary understanding of the diversity

Bioinspired organocatalytic aerobic C-H oxidation of amines with an ortho-quinone catalyst.

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Qin, Yan; Zhang, Long; Lv, Jian; Luo, Sanzhong; Cheng, Jin-Pei

2015-03-20

A simple bioinspired ortho-quinone catalyst for the aerobic oxidative dehydrogenation of amines to imines is reported. Without any metal cocatalysts, the identified optimal ortho-quinone catalyst enables the oxidations of α-branched primary amines and cyclic secondary amines. Mechanistic studies have disclosed the origins of different performances of ortho-quinone vs para-quinone in biomimetic amine oxidations.

Computational design of molecules for an all-quinone redox flow battery.

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Er, Süleyman; Suh, Changwon; Marshak, Michael P; Aspuru-Guzik, Alán

2015-02-01

Inspired by the electron transfer properties of quinones in biological systems, we recently showed that quinones are also very promising electroactive materials for stationary energy storage applications. Due to the practically infinite chemical space of organic molecules, the discovery of additional quinones or other redox-active organic molecules for energy storage applications is an open field of inquiry. Here, we introduce a high-throughput computational screening approach that we applied to an accelerated study of a total of 1710 quinone (Q) and hydroquinone (QH 2 ) ( i.e. , two-electron two-proton) redox couples. We identified the promising candidates for both the negative and positive sides of organic-based aqueous flow batteries, thus enabling an all-quinone battery. To further aid the development of additional interesting electroactive small molecules we also provide emerging quantitative structure-property relationships.

Electrochemical Reduction of Quinones in Different Media: A Review

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Partha Sarathi Guin

2011-01-01

Full Text Available The electron transfer reactions involving quinones, hydroquinones, and catechols are very important in many areas of chemistry, especially in biological systems. The therapeutic efficiency as well as toxicity of anthracycline anticancer drugs, a class of anthraquinones, is governed by their electrochemical properties. Other quinones serve as important functional moiety in various biological systems like electron-proton carriers in the respiratory chain and their involvement in photosynthetic electron flow systems. The present paper summarizes literatures on the reduction of quinones in different solvents under various conditions using different electrochemical methods. The influence of different reaction conditions including pH of the media, nature of supporting electrolytes, nature of other additives, intramolecular or intermolecular hydrogen bonding, ion pair formation, polarity of the solvents, stabilization of the semiquinone and quinone dianion, catalytic property, and adsorption at the electrode surface, are discussed and relationships between reaction conditions and products formed have been presented.

Immunomodulatory Effects of Diterpene Quinone Derivatives from the Roots of Horminum pyrenaicum in Human PBMC

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K. Becker

2018-01-01

Full Text Available Several phytochemicals were shown to interfere with redox biology in the human system. Moreover, redox biochemistry is crucially involved in the orchestration of immunological cascades. When screening for immunomodulatory compounds, the two interferon gamma- (IFN-γ- dependent immunometabolic pathways of tryptophan breakdown via indoleamine 2,3-dioxygenase-1 (IDO-1 and neopterin formation by GTP-cyclohydrolase 1 (GTP-CH-I represent prominent targets, as IFN-γ-related signaling is strongly sensitive to oxidative triggers. Herein, the analysis of these pathway activities in human peripheral mononuclear cells was successfully applied in a bioactivity-guided fractionation strategy to screen for anti-inflammatory substances contained in the root of Horminum (H. pyrenaicum L. (syn. Dragon’s mouth, the only representative of the monophyletic genus Horminum. Four abietane diterpene quinone derivatives (horminone, 7-O-acetylhorminone, inuroyleanol and its 15,16-dehydro-derivative, a novel natural product, two nor-abietane diterpene quinones (agastaquinone and 3-deoxyagastaquinone and two abeo 18 (4 → 3 abietane diterpene quinones (agastol and its 15,16-dehydro-derivative could be identified. These compounds were able to dose-dependently suppress the above mentioned pathways with different potency. Beside the description of new active compounds, this study demonstrates the feasibility of integrating IDO-1 and GTP-CH-I activity in the search for novel anti-inflammatory compounds, which can then be directed towards a more detailed mode of action analysis.

Oxygen control of nif gene expression in Klebsiella pneumoniae depends on NifL reduction at the cytoplasmic membrane by electrons derived from the reduced quinone pool.

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Grabbe, Roman; Schmitz, Ruth A

2003-04-01

In Klebsiella pneumoniae, the flavoprotein, NifL regulates NifA mediated transcriptional activation of the N2-fixation (nif) genes in response to molecular O2 and ammonium. We investigated the influence of membrane-bound oxidoreductases on nif-regulation by biochemical analysis of purified NifL and by monitoring NifA-mediated expression of nifH'-'lacZ reporter fusions in different mutant backgrounds. NifL-bound FAD-cofactor was reduced by NADH only in the presence of a redox-mediator or inside-out vesicles derived from anaerobically grown K. pneumoniae cells, indicating that in vivo NifL is reduced by electrons derived from membrane-bound oxidoreductases of the anaerobic respiratory chain. This mechanism is further supported by three lines of evidence: First, K. pneumoniae strains carrying null mutations of fdnG or nuoCD showed significantly reduced nif-induction under derepressing conditions, indicating that NifL inhibition of NifA was not relieved in the absence of formate dehydrogenase-N or NADH:ubiquinone oxidoreductase. The same effect was observed in a heterologous Escherichia coli system carrying a ndh null allele (coding for NADH dehydrogenaseII). Second, studying nif-induction in K. pneumoniae revealed that during anaerobic growth in glycerol, under nitrogen-limitation, the presence of the terminal electron acceptor nitrate resulted in a significant decrease of nif-induction. The final line of evidence is that reduced quinone derivatives, dimethylnaphthoquinol and menadiol, are able to transfer electrons to the FAD-moiety of purified NifL. On the basis of these data, we postulate that under anaerobic and nitrogen-limited conditions, NifL inhibition of NifA activity is relieved by reduction of the FAD-cofactor by electrons derived from the reduced quinone pool, generated by anaerobic respiration, that favours membrane association of NifL. We further hypothesize that the quinol/quinone ratio is important for providing the signal to NifL.

On-column reduction of catecholamine quinones in stainless steel columns during liquid chromatography.

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Xu, R; Huang, X; Kramer, K J; Hawley, M D

1995-10-10

The chromatographic behavior of quinones derived from the oxidation of dopamine and N-acetyldopamine has been studied using liquid chromatography (LC) with both a diode array detector and an electrochemical detector that has parallel dual working electrodes. When stainless steel columns are used, an anodic peak for the oxidation of the catecholamine is observed at the same retention time as a cathodic peak for the reduction of the catecholamine quinone. In addition, the anodic peak exhibits a tail that extends to a second anodic peak for the catecholamine. The latter peak occurs at the normal retention time of the catecholamine. The origin of this phenomenon has been studied and metallic iron in the stainless steel components of the LC system has been found to reduce the quinones to their corresponding catecholamines. The simultaneous appearance of a cathodic peak for the reduction of catecholamine quinone and an anodic peak for the oxidation of the corresponding catecholamine occurs when metallic iron in the exit frit reduces some of the quinones as the latter exits the column. This phenomenon is designated as the "concurrent anodic-cathodic response." It is also observed for quinones of of 3,4-dihydroxybenzoic acid and probably occurs with o- or p-quinones of other dihydroxyphenyl compounds. The use of nonferrous components in LC systems is recommended to eliminate possible on-column reduction of quinones.

Electron Transfer between Electrically Conductive Minerals and Quinones

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Olga Taran

2017-07-01

Full Text Available Long-distance electron transfer in marine environments couples physically separated redox half-reactions, impacting biogeochemical cycles of iron, sulfur and carbon. Bacterial bio-electrochemical systems that facilitate electron transfer via conductive filaments or across man-made electrodes are well-known, but the impact of abiotic currents across naturally occurring conductive and semiconductive minerals is poorly understood. In this paper I use cyclic voltammetry to explore electron transfer between electrodes made of common iron minerals (magnetite, hematite, pyrite, pyrrhotite, mackinawite, and greigite, and hydroquinones—a class of organic molecules found in carbon-rich sediments. Of all tested minerals, only pyrite and magnetite showed an increase in electric current in the presence of organic molecules, with pyrite showing excellent electrocatalytic performance. Pyrite electrodes performed better than commercially available glassy carbon electrodes and showed higher peak currents, lower overpotential values and a smaller separation between oxidation and reduction peaks for each tested quinone. Hydroquinone oxidation on pyrite surfaces was reversible, diffusion controlled, and stable over a large number of potential cycles. Given the ubiquity of both pyrite and quinones, abiotic electron transfer between minerals and organic molecules is likely widespread in Nature and may contribute to several different phenomena, including anaerobic respiration of a wide variety of microorganisms in temporally anoxic zones or in the proximity of hydrothermal vent chimneys, as well as quinone cycling and the propagation of anoxic zones in organic rich waters. Finally, interactions between pyrite and quinones make use of electrochemical gradients that have been suggested as an important source of energy for the origins of life on Earth. Ubiquinones and iron sulfide clusters are common redox cofactors found in electron transport chains across all domains

Electron Transfer Between Electrically Conductive Minerals and Quinones

Science.gov (United States)

Taran, Olga

2017-07-01

Long-distance electron transfer in marine environments couples physically separated redox half-reactions, impacting biogeochemical cycles of iron, sulfur and carbon. Bacterial bio-electrochemical systems that facilitate electron transfer via conductive filaments or across man-made electrodes are well known, but the impact of abiotic currents across naturally occurring conductive and semiconducitve minerals is poorly understood. In this paper I use cyclic voltammetry to explore electron transfer between electrodes made of common iron minerals (magnetite, hematite, pyrite, pyrrhotite, mackinawite and greigite), and hydroquinones - a class of organic molecules found in carbon-rich sediments. Of all tested minerals, only pyrite and magnetite showed an increase in electric current in the presence of organic molecules, with pyrite showing excellent electrocatalytic performance. Pyrite electrodes performed better than commercially available glassy carbon electrodes and showed higher peak currents, lower overpotential values and a smaller separation between oxidation and reduction peaks for each tested quinone. Hydroquinone oxidation on pyrite surfaces was reversible, diffusion controlled, and stable over a large number of potential cycles. Given the ubiquity of both pyrite and quinones, abiotic electron transfer between minerals and organic molecules is likely widespread in Nature and may contribute to several different phenomena, including anaerobic respiration of a wide variety of microorganisms in temporally anoxic zones or in the proximity of hydrothermal vent chimneys, as well as quinone cycling and the propagation of anoxic zones in organic rich waters. Finally, interactions between pyrite and quinones make use of electrochemical gradients that have been suggested as an important source of energy for the origins of life on Earth. Ubiquinones and iron sulfide clusters are common redox cofactors found in electron transport chains across all domains of life and

Identification of quinone imine containing glutathione conjugates of diclofenac in rat bile.

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Waldon, Daniel J; Teffera, Yohannes; Colletti, Adria E; Liu, Jingzhou; Zurcher, Danielle; Copeland, Katrina W; Zhao, Zhiyang

2010-12-20

High-resolution accurate MS with an LTQ-Orbitrap was used to identify quinone imine metabolites derived from the 5-hydroxy (5-OH) and 4 prime-hydroxy (4'-OH) glutathione conjugates of diclofenac in rat bile. The initial quinone imine metabolites formed by oxidation of diclofenac have been postulated to be reactive intermediates potentially involved in diclofenac-mediated hepatotoxicity; while these metabolites could be formed using in vitro systems, they have never been detected in vivo. This report describes the identification of secondary quinone imine metabolites derived from 5-OH and 4'-OH diclofenac glutathione conjugates in rat bile. To verify the proposed structures, the diclofenac quinone imine GSH conjugate standards were prepared synthetically and enzymatically. The novel metabolite peaks displayed the identical retention times, accurate mass MS/MS spectra, and the fragmentation patterns as the corresponding authentic standards. The formation of these secondary quinone metabolites occurs only under conditions where bile salt homeostasis was experimentally altered. Standard practice in biliary excretion experiments using bile duct-cannulated rats includes infusion of taurocholic acid and/or other bile acids to replace those lost due to continuous collection of bile; for this experiment, the rats received no replacement bile acid infusion. High-resolution accurate mass spectrometry data and comparison with chemically and enzymatically prepared quinone imines of diclofenac glutathione conjugates support the identification of these metabolites. A mechanism for the formation of these reactive quinone imine containing glutathione conjugates of diclofenac is proposed.

Respiratory quinones in Archaea: phylogenetic distribution and application as biomarkers in the marine environment.

Science.gov (United States)

Elling, Felix J; Becker, Kevin W; Könneke, Martin; Schröder, Jan M; Kellermann, Matthias Y; Thomm, Michael; Hinrichs, Kai-Uwe

2016-02-01

The distribution of respiratory quinone electron carriers among cultivated organisms provides clues on both the taxonomy of their producers and the redox processes these are mediating. Our study of the quinone inventories of 25 archaeal species belonging to the phyla Eury-, Cren- and Thaumarchaeota facilitates their use as chemotaxonomic markers for ecologically important archaeal clades. Saturated and monounsaturated menaquinones with six isoprenoid units forming the alkyl chain may serve as chemotaxonomic markers for Thaumarchaeota. Other diagnostic biomarkers are thiophene-bearing quinones for Sulfolobales and methanophenazines as functional quinone analogues of the Methanosarcinales. The ubiquity of saturated menaquinones in the Archaea in comparison to Bacteria suggests that these compounds may represent an ancestral and diagnostic feature of the Archaea. Overlap between quinone compositions of distinct thermophilic and halophilic archaea and bacteria may indicate lateral gene transfer. The biomarker potential of thaumarchaeal quinones was exemplarily demonstrated on a water column profile of the Black Sea. Both, thaumarchaeal quinones and membrane lipids showed similar distributions with maxima at the chemocline. Quinone distributions indicate that Thaumarchaeota dominate respiratory activity at a narrow interval in the chemocline, while they contribute only 9% to the microbial biomass at this depth, as determined by membrane lipid analysis. © 2015 Society for Applied Microbiology and John Wiley & Sons Ltd.

Production of quinones by in vitro cultures of Dionaea and Streptocarpus species

OpenAIRE

Nestor, Cora

2006-01-01

Quinones are a class of oxygen-containing secondary metabolites found chiefly in higher plants, fungi, bacteria and restricted in the animal kingdom to arthropods and echinoderms (Thompson 1971). In the plant, quinones, especially naphthoquinones, have been shown to function in allelopathy (juglone; Binder et al 1989), plant-insect interactions and plant-plant interactions (plumbagin; Kubo et al 1986, 1998, Spencer et al 1986, Ganapaty et al 2004). These quinones also have significant in vitr...

Quinones from Heliotropium ovalifolium.

Science.gov (United States)

Guntern, A; Ioset, J R; Queiroz, E F; Foggin, C M; Hostettmann, K

2001-10-01

Two new benzoquinones, heliotropinones A and B, have been isolated from the aerial parts of Heliotropium ovalifolium. Their structures were elucidated by spectrometric methods including high resolution electrospray ionization (ESI-HR), EI mass spectrometry, 1H, 13C and 2D NMR experiments. The two quinones demonstrated antifungal activities against Cladosporium cucumerinum and Candida albicans as well as antibacterial activity against Bacillus subtilis.

Catalytic asymmetric diels-alder reaction of quinone imine ketals: a site-divergent approach.

Science.gov (United States)

Hashimoto, Takuya; Nakatsu, Hiroki; Maruoka, Keiji

2015-04-07

The catalytic asymmetric Diels-Alder reaction of quinone imine ketals with diene carbamates catalyzed by axially chiral dicarboxylic acids is reported herein. A variety of primary and secondary alkyl-substituted quinone derivatives which have not been applied in previous asymmetric quinone Diels-Alder reactions could be employed using this method. More importantly, we succeeded in developing a strategy to divert the reaction site in unsymmetrical 3-alkyl quinone imine ketals from the inherently favored unsubstituted C=C bond to the disfavored alkyl-substituted C=C bond. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Chemical modification of b-lactoglobulin by quinones

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DUSAN SLADIC

2003-05-01

Full Text Available The avarone/avarol quinone/hydroquinone couple, as well as their derivatives show considerable antitumor activity. In this work, covalent modifications of b-lactoglobulin, isolated from cow milk, by avarone, its model compound 2-tert-butyl-1,4-benzoquinone, and several of their alkylthio derivatives were studied. The techniques applied for assaying the modifications were: UV/VIS spectrophotometry, SDS PAGE and isoelectrofocusing. The results of the SDS PAGE suggest that polymerisation of the protein occurs. The shift of the pI of the protein upon modification toward lower values indicates that lysine amino groups are the principal site of the reaction of b-lactoglobulin with the quinones.

The regioselectivity of glutathione adduct formation with flavonoid quinone methides is pH-dependent

NARCIS (Netherlands)

Awad, H.M.; Boersma, M.G.; Boeren, S.; Vervoort, J.; Bladeren, van P.J.; Rietjens, I.M.C.M.

2002-01-01

In the present study, the formation of glutathionyl adducts from a series of 3',4'-dihydroxy flavonoid o-quinone/p-quinone methides was investigated with special emphasis on the regioselectivity of the glutathione addition as a function of pH. The flavonoid o-quinones were generated using

High-capacity aqueous zinc batteries using sustainable quinone electrodes

Science.gov (United States)

Zhao, Qing; Huang, Weiwei; Luo, Zhiqiang; Liu, Luojia; Lu, Yong; Li, Yixin; Li, Lin; Hu, Jinyan; Ma, Hua; Chen, Jun

2018-01-01

Quinones, which are ubiquitous in nature, can act as sustainable and green electrode materials but face dissolution in organic electrolytes, resulting in fast fading of capacity and short cycle life. We report that quinone electrodes, especially calix[4]quinone (C4Q) in rechargeable metal zinc batteries coupled with a cation-selective membrane using an aqueous electrolyte, exhibit a high capacity of 335 mA h g−1 with an energy efficiency of 93% at 20 mA g−1 and a long life of 1000 cycles with a capacity retention of 87% at 500 mA g−1. The pouch zinc batteries with a respective depth of discharge of 89% (C4Q) and 49% (zinc anode) can deliver an energy density of 220 Wh kg−1 by mass of both a C4Q cathode and a theoretical Zn anode. We also develop an electrostatic potential computing method to demonstrate that carbonyl groups are active centers of electrochemistry. Moreover, the structural evolution and dissolution behavior of active materials during discharge and charge processes are investigated by operando spectral techniques such as IR, Raman, and ultraviolet-visible spectroscopies. Our results show that batteries using quinone cathodes and metal anodes in aqueous electrolyte are reliable approaches for mass energy storage. PMID:29511734

Interaction of quinones with three pyrimidine bases: A laser flash photolysis study

Energy Technology Data Exchange (ETDEWEB)

Bose, Adity [Chemical Sciences Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700064 (India); Basu, Samita, E-mail: samita.basu@saha.ac.i [Chemical Sciences Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700064 (India)

2009-11-15

The interaction between three different pyrimidine bases, uracil (U), cytosine (C) and thymine (T) and two quinones, 2-methyl-1,4-naphthoquinone or menadione (MQ) and 9,10-anthraquinone (AQ) have been studied using laser flash photolysis technique in organic homogeneous medium. The three pyrimidines have revealed a difference in their extent of reactivity towards the quinones, which has been attributed to their structural difference. Our works have revealed that the difference in structural dimension of the quinones is also responsible for affecting the reactivity of these pyrimidines in homogeneous medium.

Interaction of quinones with three pyrimidine bases: A laser flash photolysis study

International Nuclear Information System (INIS)

Bose, Adity; Basu, Samita

2009-01-01

The interaction between three different pyrimidine bases, uracil (U), cytosine (C) and thymine (T) and two quinones, 2-methyl-1,4-naphthoquinone or menadione (MQ) and 9,10-anthraquinone (AQ) have been studied using laser flash photolysis technique in organic homogeneous medium. The three pyrimidines have revealed a difference in their extent of reactivity towards the quinones, which has been attributed to their structural difference. Our works have revealed that the difference in structural dimension of the quinones is also responsible for affecting the reactivity of these pyrimidines in homogeneous medium.

Quinone-dependent D-lactate dehydrogenase Dld (Cg1027 is essential for growth of Corynebacterium glutamicum on D-lactate

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Oikawa Tadao

2010-12-01

Full Text Available Abstract Background Corynebacterium glutamicum is able to grow with lactate as sole or combined carbon and energy source. Quinone-dependent L-lactate dehydrogenase LldD is known to be essential for utilization of L-lactate by C. glutamicum. D-lactate also serves as sole carbon source for C. glutamicum ATCC 13032. Results Here, the gene cg1027 was shown to encode the quinone-dependent D-lactate dehydrogenase (Dld by enzymatic analysis of the protein purified from recombinant E. coli. The absorption spectrum of purified Dld indicated the presence of FAD as bound cofactor. Inactivation of dld resulted in the loss of the ability to grow with D-lactate, which could be restored by plasmid-borne expression of dld. Heterologous expression of dld from C. glutamicum ATCC 13032 in C. efficiens enabled this species to grow with D-lactate as sole carbon source. Homologs of dld of C. glutamicum ATCC 13032 are not encoded in the sequenced genomes of other corynebacteria and mycobacteria. However, the dld locus of C. glutamicum ATCC 13032 shares 2367 bp of 2372 bp identical nucleotides with the dld locus of Propionibacterium freudenreichii subsp. shermanii, a bacterium used in Swiss-type cheese making. Both loci are flanked by insertion sequences of the same family suggesting a possible event of horizontal gene transfer. Conclusions Cg1067 encodes quinone-dependent D-lactate dehydrogenase Dld of Corynebacterium glutamicum. Dld is essential for growth with D-lactate as sole carbon source. The genomic region of dld likely has been acquired by horizontal gene transfer.

Antitrypanosomal isoflavan quinones from Abrus precatorius

CSIR Research Space (South Africa)

Hata, Y

2014-03-01

Full Text Available Fitoterapia Vol. 93, pp 81-87 Antitrypanosomal isoflavan quinones from Abrus precatorius Yoshie Hata a,d, Samad Nejad Ebrahimi a,e, Maria De Mieri a, Stefanie Zimmermann a, Tsholofelo Mokoka c, Dashnie Naidoo c, Gerda Fouche c, Vinesh Maharaj c...

Quinones: reactions with hemoglobin, effects within erythrocytes and potential for antimalarial development

International Nuclear Information System (INIS)

Denny, B.J.

1986-01-01

The focus of this research was to characterize the interactions of some simple quinone like compounds with purified hemoglobin and to study the effects of these compounds within erythrocytes. It is proposed that these sorts of agents can have an antimalarial effect. The simplest compounds chosen for study were benzoquinone, methylquinone (toluquinone) and hydroquinone. When 14 C-quinone was reacted with purified hemoglobin (Hb) there was rapid binding of the first two moles of substrate per Hb molecule. An unusual property of the modified Hb's is that in the presence of a redox sensitive agent such as cytochrome c they are capable of generating superoxide anions. Within erythrocytes, quinone and toluquinone which differ only by a single methyl group have completely different effects. Toluquinone causes the cells to hemolyse and the effect was enhanced when the erythrocyte superoxide dismutase was inhibited; the effect was diminished when scavengers of activated oxygen such as histidine, mannitol and vital E were present. Benzoquinone on the other hand did not cause the cells to hemolyse and instead appeared to protect the cells from certain hemolytic stresses. Growth of malaria parasites in erythrocytes has been shown to be inhibited by activated forms of oxygen, also some quinone like agents in the past have been shown to inhibit the parasite's metabolism. An initial experiment with erythrocytes infected with malaria parasites showed that quinone and toluquinone could both inhibit the growth rate of parasites

Bioinspired aerobic oxidation of secondary amines and nitrogen heterocycles with a bifunctional quinone catalyst.

Science.gov (United States)

Wendlandt, Alison E; Stahl, Shannon S

2014-01-08

Copper amine oxidases are a family of enzymes with quinone cofactors that oxidize primary amines to aldehydes. The native mechanism proceeds via an iminoquinone intermediate that promotes high selectivity for reactions with primary amines, thereby constraining the scope of potential biomimetic synthetic applications. Here we report a novel bioinspired quinone catalyst system consisting of 1,10-phenanthroline-5,6-dione/ZnI2 that bypasses these constraints via an abiological pathway involving a hemiaminal intermediate. Efficient aerobic dehydrogenation of non-native secondary amine substrates, including pharmaceutically relevant nitrogen heterocycles, is demonstrated. The ZnI2 cocatalyst activates the quinone toward amine oxidation and provides a source of iodide, which plays an important redox-mediator role to promote aerobic catalytic turnover. These findings provide a valuable foundation for broader development of aerobic oxidation reactions employing quinone-based catalysts.

Enhanced bio-decolorization of azo dyes by co-immobilized quinone-reducing consortium and anthraquinone

DEFF Research Database (Denmark)

Su, YY; Zhang, Yifeng; Wang, J

2009-01-01

In the present study, the accelerating effect of co-immobilized anthraquinone and quinone-reducing consortium was investigated in the bio-decolorization process. The anthraquinone and quinone-reducing consortium were co-immobilized by entrapment in calcium alginate. The co-immobilized beads...

X-ray structural studies of quinone reductase 2 nanomolar range inhibitors

Energy Technology Data Exchange (ETDEWEB)

Pegan, Scott D.; Sturdy, Megan; Ferry, Gilles; Delagrange, Philippe; Boutin, Jean A.; Mesecar, Andrew D. (IdRS); (Purdue); (Colorado); (UIC)

2011-09-06

Quinone reductase 2 (QR2) is one of two members comprising the mammalian quinone reductase family of enzymes responsible for performing FAD mediated reductions of quinone substrates. In contrast to quinone reductase 1 (QR1) which uses NAD(P)H as its co-substrate, QR2 utilizes a rare group of hydride donors, N-methyl or N-ribosyl nicotinamide. Several studies have linked QR2 to the generation of quinone free radicals, several neuronal degenerative diseases, and cancer. QR2 has been also identified as the third melatonin receptor (MT3) through in cellulo and in vitro inhibition of QR2 by traditional MT3 ligands, and through recent X-ray structures of human QR2 (hQR2) in complex with melatonin and 2-iodomelatonin. Several MT3 specific ligands have been developed that exhibit both potent in cellulo inhibition of hQR2 nanomolar, affinity for MT3. The potency of these ligands suggest their use as molecular probes for hQR2. However, no definitive correlation between traditionally obtained MT3 ligand affinity and hQR2 inhibition exists limiting our understanding of how these ligands are accommodated in the hQR2 active site. To obtain a clearer relationship between the structures of developed MT3 ligands and their inhibitory properties, in cellulo and in vitro IC{sub 50} values were determined for a representative set of MT3 ligands (MCA-NAT, 2-I-MCANAT, prazosin, S26695, S32797, and S29434). Furthermore, X-ray structures for each of these ligands in complex with hQR2 were determined allowing for a structural evaluation of the binding modes of these ligands in relation to the potency of MT3 ligands.

A geometric bound on F-term inflation

NARCIS (Netherlands)

Borghese, Andrea; Roest, Diederik; Zavala, Ivonne

We discuss a general bound on the possibility to realise inflation in any minimal supergravity with F-terms. The derivation crucially depends on the sGoldstini, the scalar field directions that are singled out by spontaneous supersymmetry breaking. The resulting bound involves both slow-roll

Reduction of quinones and phenoxy radicals by extracellular glucose dehydrogenase from Glomerella cingulata suggests a role in plant pathogenicity.

Science.gov (United States)

Sygmund, Christoph; Klausberger, Miriam; Felice, Alfons K; Ludwig, Roland

2011-11-01

The plant-pathogenic fungus Glomerella cingulata (anamorph Colletotrichum gloeosporoides) secretes high levels of an FAD-dependent glucose dehydrogenase (GDH) when grown on tomato juice-supplemented media. To elucidate its molecular and catalytic properties, GDH was produced in submerged culture. The highest volumetric activity was obtained in shaking flasks after 6 days of cultivation (3400 U l⁻¹, 4.2 % of total extracellular protein). GDH is a monomeric protein with an isoelectric point of 5.6. The molecular masses of the glycoforms ranged from 95 to 135 kDa, but after deglycosylation, a single 68 kDa band was obtained. The absorption spectrum is typical for an FAD-containing enzyme with maxima at 370 and 458 nm and the cofactor is non-covalently bound. The preferred substrates are glucose and xylose. Suitable electron acceptors are quinones, phenoxy radicals, 2,6-dichloroindophenol, ferricyanide and ferrocenium hexafluorophosphate. In contrast, oxygen turnover is very low. The GDH-encoding gene was cloned and phylogenetic analysis of the translated protein reveals its affiliation to the GMC family of oxidoreductases. The proposed function of this quinone and phenoxy radical reducing enzyme is to neutralize the action of plant laccase, phenoloxidase or peroxidase activities, which are increased in infected plants to evade fungal attack.

Preliminary X-ray crystallographic analysis of sulfide:quinone oxidoreductase from Acidithiobacillus ferrooxidans

International Nuclear Information System (INIS)

Zhang, Yanfei; Cherney, Maia M.; Solomonson, Matthew; Liu, Jianshe; James, Michael N. G.; Weiner, Joel H.

2009-01-01

The sulfide:quinone oxidoreductase from A. ferrooxidans ATCC 23270 was overexpressed in E. coli and purified. Crystallization and preliminarily X-ray crystallographic analysis were performed for the recombinant enzyme. The gene product of open reading frame AFE-1293 from Acidithiobacillus ferrooxidans ATCC 23270 is annotated as encoding a sulfide:quinone oxidoreductase, an enzyme that catalyses electron transfer from sulfide to quinone. Following overexpression in Escherichia coli, the enzyme was purified and crystallized using the hanging-drop vapour-diffusion method. The native crystals belonged to the tetragonal space group P4 2 2 1 2, with unit-cell parameters a = b = 131.7, c = 208.8 Å, and diffracted to 2.3 Å resolution. Preliminary crystallographic analysis indicated the presence of a dimer in the asymmetric unit, with an extreme value of the Matthews coefficient (V M ) of 4.53 Å 3 Da −1 and a solvent content of 72.9%

Chemopreventive effects of free and bound phenolics associated to steep waters (nejayote) obtained after nixtamalization of different maize types.

Science.gov (United States)

Rojas-García, Carlos; García-Lara, Silverio; Serna-Saldivar, Sergio O; Gutiérrez-Uribe, Janet A

2012-03-01

Free and bound phenolics extracts from nejayote solids were obtained after optimally lime-cooking blue, normal white, red, normal yellow, high-carotenoid and quality protein maize types. The extraction yield ranged from 4.47 to 10.05%. Bound phenolics extracts had higher content of total phenolics, antioxidant activity and ferulic acid compared to the free phenolics extracts. In general, free phenolics extracts were less cytotoxic than the bound phenolics counterparts. Bound phenolics extracts had higher induction of quinone reductase (QR) and particularly the normal yellow nejayote exerted the highest chemopreventive index tested in Hepa1c1c7 cells. When tested for monofunctional phase 2 induction capacity in BPrc1 cells, the bound phenolics extracts of blue, normal white and quality protein nejayotes were better inducers than the normal yellow counterpart. Particularly, the free phenolics extract of the white maize nejayote induced BPrc1 cells QR and exerted a higher chemopreventive index compared to the bound phenolics extract. Therefore, the nejayote of the normal white maize was the best source of monofunctional phase 2 enzyme inducers.

Quinone-Enriched Gold Nanoparticles in Bioelectrochemistry and Charge Storage

DEFF Research Database (Denmark)

Wagner, Michal; Qvortrup, Katrine; Tanner, David Ackland

for merging gold nanoparticles with resultant anthraquinones include one-pot microwave assisted synthesis or after-mixing of separately prepared gold nanoparticles with selected compounds. The quinone-enriched gold nanoparticles can be transferred onto different electrode surfaces, thus enabling facile...

Identification of Carotenoids and Isoprenoid Quinones from Asaia lannensis and Asaia bogorensis

Directory of Open Access Journals (Sweden)

Hubert Antolak

2017-09-01

Full Text Available The aim of the study was to identify and quantitatively assess of carotenoids and isoprenoid quinones biosynthesized by six different strains of acetic acid bacteria, belonging to genus Asaia, that are common beverage-spoiling bacteria in Europe. Bacterial cultures were conducted in a laboratory liquid culture minimal medium with 2% sucrose. Carotenoids and isoprenoid quinones were investigated using UHPLC-DAD-ESI-MS analysis. In general, tested strains of Asaia spp. were able to produce 10 carotenoids and 3 isoprenoid quinones: menaquinone-7, menaquinone-8, and ubiquinone-10. The main identified carotenoids in Asaia lannensis strains were phytofluene, neurosporene, α-carotene, while for Asaia bogorensis, neurosporene, canthaxanthin, and zeaxanthin were noted. What is more, tested Asaia spp. were able to produce myxoxanthophyll, which has so far been identified primarily in cyanobacteria. The results show that A. lannensis are characterized by statistically higher concentrations of produced carotenoids, as well as a greater variety of these compounds. We have noted that carotenoids were not only accumulated by bacterial cells, but also some strains of A. lannensis produced extracellular carotenoids.

Computational design of molecules for an all-quinone redox flow battery† †Electronic supplementary information (ESI) available: The list of computationally predicted candidate quinone molecules with interesting redox properties. See DOI: 10.1039/c4sc03030c Click here for additional data file.

Science.gov (United States)

Er, Süleyman; Suh, Changwon; Marshak, Michael P.

2015-01-01

Inspired by the electron transfer properties of quinones in biological systems, we recently showed that quinones are also very promising electroactive materials for stationary energy storage applications. Due to the practically infinite chemical space of organic molecules, the discovery of additional quinones or other redox-active organic molecules for energy storage applications is an open field of inquiry. Here, we introduce a high-throughput computational screening approach that we applied to an accelerated study of a total of 1710 quinone (Q) and hydroquinone (QH2) (i.e., two-electron two-proton) redox couples. We identified the promising candidates for both the negative and positive sides of organic-based aqueous flow batteries, thus enabling an all-quinone battery. To further aid the development of additional interesting electroactive small molecules we also provide emerging quantitative structure-property relationships. PMID:29560173

Membrane protein damage and repair: selective loss of a quinone-protein function in chloroplast membranes

International Nuclear Information System (INIS)

Kyle, D.J.; Ohad, I.; Arntzen, C.J.

1984-01-01

A loss of electron transport capacity in chloroplast membranes was induced by high-light intensities (photoinhibition). The primary site of inhibition was at the reducing side of photosystem II (PSII) with little damage to the oxidizing side or to the reaction center core of PSII. Addition of herbicides (atrazine or diuron) partially protected the membrane from photoinhibition; these compounds displace the bound plastoquinone (designated as Q/sub B/), which functions as the secondary electron acceptor on the reducing side of PSII. Loss of function of the 32-kilodalton Q/sub B/ apoprotein was demonstrated by a loss of binding sites for [ 14 C]atraazine. We suggest that quinone anions, which may interact with molecular oxygen to produce an oxygen radical, selectively damage the apoprotein of the secondary acceptor of PSII, thus rendering it inactive and thereby blocking photosynthetic electron flow under conditions of high photon flux densities. 21 references, 4 figures, 2 tables

Toxicity to sea urchin egg development of the quinone fraction obtained from Auxemma oncocalyx

Directory of Open Access Journals (Sweden)

Costa-Lotufo L.V.

2002-01-01

Full Text Available Auxemma oncocalyx Taub. belongs to the Boraginaceae family and is native to the Brazilian northeast where it is known as "pau-branco". We investigated the ability of the water soluble fraction isolated from the heartwood of A. oncocalyx to inhibit sea urchin egg development. This fraction contains about 80% oncocalyxone A (quinone fraction, a compound known to possess strong cytotoxic and antitumor activities. In fact, the quinone fraction inhibited cleavage in a dose-dependent manner [IC50 of 18.4 (12.4-27.2 µg/ml, N = 6], and destroyed the embryos in the blastula stage [IC50 of 16.2 (13.7-19.2 µg/ml, N = 6]. We suggest that this activity is due to the presence of oncocalyxone A. In fact, these quinones present in A. oncocalyx extract have strong toxicity related to their antimitotic activity.

Photo-bleaching of polymer discoloration caused by quinone methides

Czech Academy of Sciences Publication Activity Database

Pospíšil, Jan; Nešpůrek, Stanislav; Zweifel, H.; Kuthan, J.

2002-01-01

Roč. 78, č. 2 (2002), s. 251-255 ISSN 0141-3910 R&D Projects: GA AV ČR IAA1050901 Institutional research plan: CEZ:AV0Z4050913 Keywords : quinone methide * photo- bleaching * polymer discoloration Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.145, year: 2002

Electron transfer capacity dependence of quinone-mediated Fe(III) reduction and current generation by Klebsiella pneumoniae L17.

Science.gov (United States)

Li, Xiaomin; Liu, Liang; Liu, Tongxu; Yuan, Tian; Zhang, Wei; Li, Fangbai; Zhou, Shungui; Li, Yongtao

2013-06-01

Quinone groups in exogenous electron shuttles can accelerate extracellular electron transfer (EET) from bacteria to insoluble terminal electron acceptors, such as Fe(III) oxides and electrodes, which are important in biogeochemical redox processes and microbial electricity generation. However, the relationship between quinone-mediated EET performance and electron-shuttling properties of the quinones remains incompletely characterized. This study investigates the effects of a series of synthetic quinones (SQs) on goethite reduction and current generation by a fermenting bacterium Klebsiella pneumoniae L17. In addition, the voltammetric behavior and electron transfer capacities (ETCs) of SQ, including electron accepting (EAC) and donating (EDC) capacities, is also examined using electrochemical methods. The results showed that SQ can significantly increase both the Fe(III) reduction rates and current outputs of L17. Each tested SQ reversibly accepted and donated electrons as indicated by the cyclic voltammograms. The EAC and EDC results showed that Carmine and Alizarin had low relative capacities of electron transfer, whereas 9,10-anthraquinone-2,6-disulfonic acid (AQDS), 2-hydroxy-1,4-naphthoquinone (2-HNQ), and 5-hydroxy-1,4-naphthoquinone (5-HNQ) showed stronger relative ETC, and 9,10-anthraquinone-2-carboxylic acid (AQC) and 9,10-anthraquinone-2-sulfonic acid (AQS) had high relative ETC. Enhancement of microbial goethite reduction kinetics and current outputs by SQ had a good linear relationship with their ETC, indicating that the effectiveness of quinone-mediated EET may be strongly dependent on the ETC of the quinones. Therefore, the presence of quinone compounds and fermenting microorganisms may increase the diversity of microbial populations that contribute to element transformation in natural environments. Moreover, ETC determination of different SQ would help to evaluate their performance for microbial EET under anoxic conditions. Copyright © 2013 Elsevier

Soluble and stable zethrenebis(dicarboximide) and its quinone

KAUST Repository

Sun, Zhe

2010-10-15

Soluble and stable zethrenebis(dicarboximide) (1) was synthesized by an in situ Stille cross coupling/transannular cyclization reaction. 1 showed largely improved photostability and solubility compared with the very unstable zethrene and it also exhibited far-red absorption and emission with high photoluminescence quantum yield. Bromination of 1 with NBS/DMF gave its quinone form 2 via an unusual pathway. © 2010 American Chemical Society.

Studies on the mechanism of quinone action on hormonal regulation of metabolism in the rat liver

International Nuclear Information System (INIS)

Cheng, E.Y.

1989-01-01

The mechanism of quinone actions in liver cell metabolism had been investigated using menadione as a model compound. Previous reports suggested that quinones and free radicals could produce perturbations in cellular calcium homeostasis. Since calcium plays an important role in the regulation of cellular metabolic processes, then regulation of cytosolic calcium concentrations, and thus of cellular metabolism, by calcium-mobilizing hormones such as phenylephrine and vasopressin could possibly be modified by quinones such as menadione. Methods used to approach this hypothesis included the assay for activation of glycogen phosphorylase, an indirect index of calcium mobilization; the determination of calcium mobilization with 45 Ca efflux exchange and with fluorescent calcium indicator fura-2; and the measurement of phosphatidylinositides, an important link in the membrane-associated receptor-mediated signal transduction mechanism

The inhibition mechanisms of quinones and phenols present in wood for the vinyl polymerization

International Nuclear Information System (INIS)

Nobashi, Kenzo; Yokota, Tokuo

1977-01-01

The inhibitory effects and mechanisms of the quinones and phenols present in wood for the vinyl polymerization initiated with γ-rays and other initiation systems were investigated. The results obtained are summarized as follows; (1) Although phenolic compounds like isotaxiresinol inhibit the γ-ray initiated polymerization of methyl methacrylate (MMA) under the presence of air, they have no inhibitory effects in vacuo. On the other hand, o-benzoquinone and mansonones show strong inhibitory or retarding effects in vacuo. These facts indicate that oxygen may be important for the phenols to inhibit the vinyl polymerization. (2) It is shown qualitatively that there is a relationship between the strength of inhibitory action of quinones and their normal redox potentials. (3) PMMA produced under the presence of o-benzoquinone is found to include the fraction having extremely large chain length based on gel permeation chromatogram. (4) Based on the reaction products of orthoquinones and azobisisobutyronitrile, which was assumed as a model of polymer radicals, the inhibition reaction with polymer chain radical is concluded to take place upon the oxygen atoms of the quinones. (auth.)

Comparative evaluation of the acceptor properties of quinone derivatized polypyridinic ligands

Energy Technology Data Exchange (ETDEWEB)

Norambuena, Ester [Departamento de Quimica, Facultad de Ciencias Basicas, Universidad Metropolitana de Ciencias de la Educacion, Santiago (Chile); Olea-Azar, Claudio [Facultad de Ciencias Quimicas y Farmaceuticas, Universidad de Chile, Santiago (Chile); Delgadillo, Alvaro [Departamento de Quimica, Facultad de Ciencias, Universidad de La Serena, Casilla 599, La Serena (Chile); Barrera, Mauricio [Facultad de Quimica, Pontificia Universidad Catolica de Chile, Casilla 306, Santiago (Chile); Loeb, Barbara, E-mail: bloeb@puc.cl [Facultad de Quimica, Pontificia Universidad Catolica de Chile, Casilla 306, Santiago (Chile)

2009-05-18

The reduction properties of four acceptor polipyridyl ligands modified with quinones were studied by different experimental methods, as cyclic voltammetry and ESR spectroscopy, and by theoretical calculations. ESR spectra for the reduced ligands show different patterns among them, suggesting that the quinone moiety plays an important role in the delocalization of the received electron. The hyperfine coupling constants calculated for the magnetic nucleus were in good agreement with experimental data. The results were additionally interpreted with the help of two theoretical predictors: the electrophilicity index and the Fukui function obtained through the spin density. The results suggest that 12,17-dihydronaphtho-[2,3-h]dipyrido[3,2-a:2',3'-c]-phenazine-12,17-dione, Aqphen, shows the most promising behavior to be employed as an acceptor ligand in complexes with potential application in NLO devices.

Comparative evaluation of the acceptor properties of quinone derivatized polypyridinic ligands

International Nuclear Information System (INIS)

Norambuena, Ester; Olea-Azar, Claudio; Delgadillo, Alvaro; Barrera, Mauricio; Loeb, Barbara

2009-01-01

The reduction properties of four acceptor polipyridyl ligands modified with quinones were studied by different experimental methods, as cyclic voltammetry and ESR spectroscopy, and by theoretical calculations. ESR spectra for the reduced ligands show different patterns among them, suggesting that the quinone moiety plays an important role in the delocalization of the received electron. The hyperfine coupling constants calculated for the magnetic nucleus were in good agreement with experimental data. The results were additionally interpreted with the help of two theoretical predictors: the electrophilicity index and the Fukui function obtained through the spin density. The results suggest that 12,17-dihydronaphtho-[2,3-h]dipyrido[3,2-a:2',3'-c]-phenazine-12,17-dione, Aqphen, shows the most promising behavior to be employed as an acceptor ligand in complexes with potential application in NLO devices.

An antibacterial ortho-quinone diterpenoid and its derivatives from Caryopteris mongolica.

Science.gov (United States)

Saruul, Erdenebileg; Murata, Toshihiro; Selenge, Erdenechimeg; Sasaki, Kenroh; Yoshizaki, Fumihiko; Batkhuu, Javzan

2015-06-15

To identify antibacterial components in traditional Mongolian medicinal plant Caryopteris mongolica, an ortho-quinone abietane caryopteron A (1) and three its derivatives caryopteron B-D (2-4) were isolated from the roots of the plant together with three known abietanes demethylcryptojaponol (5), 6α-hydroxydemethyl cryptojaponol (6), and 14-deoxycoleon U (7). The chemical structures of these abietane derivatives were elucidated on the basis of spectroscopic data. Compounds 1-4 had C-13 methylcyclopropane substructures, and 2-4 had a hexanedioic anhydride ring C instead of ortho-quinone in 1. The stereochemistry of these compound was assumed from NOE spectra and ECD Cotton effects. Compounds 1 and 5-7 showed antibacterial activities against the Gram-positive bacteria Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis, and Micrococcus luteus, being 1 the more potent. Copyright © 2015 Elsevier Ltd. All rights reserved.

UV-Vis spectrophotometry of quinone flow battery electrolyte for in situ monitoring and improved electrochemical modeling of potential and quinhydrone formation.

Science.gov (United States)

Tong, Liuchuan; Chen, Qing; Wong, Andrew A; Gómez-Bombarelli, Rafael; Aspuru-Guzik, Alán; Gordon, Roy G; Aziz, Michael J

2017-12-06

Quinone-based aqueous flow batteries provide a potential opportunity for large-scale, low-cost energy storage due to their composition from earth abundant elements, high aqueous solubility, reversible redox kinetics and their chemical tunability such as reduction potential. In an operating flow battery utilizing 9,10-anthraquinone-2,7-disulfonic acid, the aggregation of an oxidized quinone and a reduced hydroquinone to form a quinhydrone dimer causes significant variations from ideal solution behavior and of optical absorption from the Beer-Lambert law. We utilize in situ UV-Vis spectrophotometry to establish (a), quinone, hydroquinone and quinhydrone molar attenuation profiles and (b), an equilibrium constant for formation of the quinhydrone dimer (K QHQ ) ∼ 80 M -1 . We use the molar optical attenuation profiles to identify the total molecular concentration and state of charge at arbitrary mixtures of quinone and hydroquinone. We report density functional theory calculations to support the quinhydrone UV-Vis measurements and to provide insight into the dimerization conformations. We instrument a quinone-bromine flow battery with a Pd-H reference electrode in order to demonstrate how complexation in both the negative (quinone) and positive (bromine) electrolytes directly impacts measured half-cell and full-cell voltages. This work shows how accounting for electrolyte complexation improves the accuracy of electrochemical modeling of flow battery electrolytes.

Quinone-fused porphyrins as contrast agents for photoacoustic imaging

KAUST Repository

Banala, Srinivas

2017-06-27

Photoacoustic (PA) imaging is an emerging non-invasive diagnostic modality with many potential clinical applications in oncology, rheumatology and the cardiovascular field. For this purpose, there is a high demand for exogenous contrast agents with high absorption coefficients in the optical window for tissue imaging, i.e. the near infrared (NIR) range between 680 and 950 nm. We herein report the photoacoustic properties of quinone-fused porphyrins inserted with different transition metals as new highly promising candidates. These dyes exhibit intense NIR absorption, a lack of fluorescence emission, and PA sensitivity in concentrations below 3 nmol mL. In this context, the highest PA signal was obtained with a Zn(ii) inserted dye. Furthermore, this dye was stable in blood serum and free thiol solution and exhibited negligible cell toxicity. Additionally, the Zn(ii) probe could be detected with an up to 3.2 fold higher PA intensity compared to the clinically most commonly used PA agent, ICG. Thus, further exploration of the \\'quinone-fusing\\' approach to other chromophores may be an efficient way to generate highly potent PA agents that do not fluoresce and shift their absorption into the NIR range.

Monitoring of BHT-quinone and BHT-CHO in the gas of capsules of Asclepias physocarpa.

Science.gov (United States)

Ma, Bing-Ji; Peng, Hua; Liu, Ji-Kai

2006-01-01

Three volatile components, namely benzoic acid ethyl ester (1), 2,6-di-tert-butyl-p-benzoquinone (BHT-quinone) (2), and 3,5-di-tert-butyl-4-hydroxybenzaldehyde (BHT-CHO) (3), were detected from the gas in the capsules of Asclepias physocarpa by means of GC/MS analysis. BHT-quinone and BHT-CHO as organic pollutants are the degradation products of the antioxidant 2,6-di-tert-butyl-4-methylphenol (BHT). Ground water, lake water and/or rain water are a source of BHT metabolites in the plant Asclepias physocarpa.

All three quinone species play distinct roles in ensuring optimal growth under aerobic and fermentative conditions in E. coli K12

Science.gov (United States)

Nitzschke, Annika

2018-01-01

The electron transport chain of E. coli contains three different quinone species, ubiquinone (UQ), menaquinone (MK) and demethylmenaquinone (DMK). The content and ratio of the different quinone species vary depending on the external conditions. To study the function of the different quinone species in more detail, strains with deletions preventing UQ synthesis, as well as MK and/or DMK synthesis were cultured under aerobic and anaerobic conditions. The strains were characterized with respect to growth and product synthesis. As quinones are also involved in the control of ArcB/A activity, we analyzed the phosphorylation state of the response regulator as well as the expression of selected genes.The data show reduced aerobic growth coupled to lactate production in the mutants defective in ubiquinone synthesis. This confirms the current assumption that ubiquinone is the main quinone under aerobic growth conditions. In the UQ mutant strains the amount of MK and DMK is significantly elevated. The strain synthesizing only DMK is less affected in growth than the strain synthesizing MK as well as DMK. An inhibitory effect of MK on aerobic growth due to increased oxidative stress is postulated.Under fermentative growth conditions the mutant synthesizing only UQ is severely impaired in growth. Obviously, UQ is not able to replace MK and DMK during anaerobic growth. Mutations affecting quinone synthesis have an impact on ArcA phosphorylation only under anaerobic conditions. ArcA phosphorylation is reduced in strains synthesizing only MK or MK plus DMK. PMID:29614086

Carbons, ionic liquids and quinones for electrochemical capacitors

Directory of Open Access Journals (Sweden)

Raul eDiaz

2016-04-01

Full Text Available Carbons are the main electrode materials used in electrochemical capacitors, which are electrochemical energy storage devices with high power densities and long cycling lifetimes. However, increasing their energy density will improve their potential for commercial implementation. In this regard, the use of high surface area carbons and high voltage electrolytes are well known strategies to increase the attainable energy density, and lately ionic liquids have been explored as promising alternatives to current state of the art acetonitrile-based electrolytes. Also, in terms of safety and sustainability ionic liquids are attractive electrolyte materials for electrochemical capacitors. In addition, it has been shown that the matching of the carbon pore size with the electrolyte ion size further increases the attainable electric double layer (EDL capacitance and energy density.The use of pseudocapacitive reactions can significantly increase the attainable energy density, and quinonic-based materials offer a potentially sustainable and cost effective research avenue for both the electrode and the electrolyte. This perspective will provide an overview of the current state of the art research on electrochemical capacitors based on combinations of carbons, ionic liquids and quinonic compounds, highlighting performances and challenges and discussing possible future research avenues. In this regard, current interest is mainly focused on strategies which may ultimately lead to commercially competitive sustainable high performance electrochemical capacitors for different applications including those requiring mechanical flexibility and biocompatibility.

Quenching of bacteriochlorophyll fluorescence in chlorosomes from Chloroflexus aurantiacus by exogenous quinones

DEFF Research Database (Denmark)

Tokita, S; Frigaard, N-U; Hirota, M

2000-01-01

The quenching of bacteriochlorophyll (BChl) c fluorescence in chlorosomes isolated from Chloroflexus aurantiacus was examined by the addition of various benzoquinones, naphthoquinones (NQ), and anthraquinones (AQ). Many quinones showed strong quenching in the micromolar or submicromolar range. Th...

Quinone exchange at the A{sub 1} site in photosystem I [PSI

Energy Technology Data Exchange (ETDEWEB)

Barkoff, A.; Brunkan, N.; Snyder, S.W.; Ostafin, A.; Werst, M.; Thurnauer, M.C. [Argonne National Lab., IL (United States); Biggins, J. [Brown Univ., Providence, RI (United States)

1995-12-31

Quinones play an essential role in light-induced electron transport in photosynthetic reaction centers (RC). Study of quinone binding within the protein matrix of the RC is a focal point of understanding the biological optimization of photosynthesis. In plant and cyanobacterial PSI, phylloquinone (K{sub 1}) is believed to be the secondary electron acceptor, A{sub 1}, similar to Q{sub a} in the purple bacterial RC. Photoinduced electron transfer is initiated by reduction of the electron acceptor (A{sub 0}), a chlorophyll species, by the photoexcited primary donor *P{sub 700}. A{sub 1} acts as a transient redox intermediate between A{sub 0} and the iron-sulfur centers (FeS). We have examined the characteristic PSI electron spin polarized (ESP) electron paramagnetic resonance (EPR) signal as a marker of the interacting radical pairs developed during electron transfer.

Effects of oxygen radical scavengers on the inactivation of SS phi X174 DNA by the semi-quinone free radical of the antitumor agent etoposide

NARCIS (Netherlands)

van Maanen, M.J.; Mans, D.R.A.; Lafleur, M.V.M.; Van Schaik, M A; de Vries, J; Vermeulen, N P; Retèl, J.; Lankelma, J

1990-01-01

We have studied the effects of oxygen radical scavengers on the inactivation of ss phi X174 DNA by the semi-quinone free radical of the antitumor agent etoposide (VP 16-213), which was generated from the ortho-quinone of etoposide at pH greater than or equal to 7.4. A semi-quinone free radical of

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

The Role of Human Aldo-Keto Reductases in the Metabolic Activation and Detoxication of Polycyclic Aromatic Hydrocarbons: Interconversion of PAH Catechols and PAH o-Quinones

Science.gov (United States)

Zhang, Li; Jin, Yi; Huang, Meng; Penning, Trevor M.

2012-01-01

Polycyclic aromatic hydrocarbons (PAH) are ubiquitous environmental pollutants. They are procarcinogens requiring metabolic activation to elicit their deleterious effects. Aldo-keto reductases (AKR) catalyze the oxidation of proximate carcinogenic PAH trans-dihydrodiols to yield electrophilic and redox-active PAH o-quinones. AKRs are also found to be capable of reducing PAH o-quinones to form PAH catechols. The interconversion of o-quinones and catechols results in the redox-cycling of PAH o-quinones to give rise to the generation of reactive oxygen species and subsequent oxidative DNA damage. On the other hand, PAH catechols can be intercepted through phase II metabolism by which PAH o-quinones could be detoxified and eliminated. The aim of the present review is to summarize the role of human AKRs in the metabolic activation/detoxication of PAH and the relevance of phase II conjugation reactions to human lung carcinogenesis. PMID:23162467

Measuring protection of aromatic wine thiols from oxidation by competitive reactions vs wine preservatives with ortho-quinones.

Science.gov (United States)

Nikolantonaki, Maria; Magiatis, Prokopios; Waterhouse, Andrew L

2014-11-15

Quinones are central intermediates in wine oxidation that can degrade the quality of wine by reactions with varietal thiols, such as 3-sulfanylhexanol, decreasing desirable aroma. Protection by wine preservatives (sulphur dioxide, glutathione, ascorbic acid and model tannin, phloroglucinol) was assessed by competitive sacrificial reactions with 4-methyl-1,2-benzoquinone, quantifying products and ratios by HPLC-UV-MS. Regioselectivity was assessed by product isolation and identification by NMR spectroscopy. Nucleophilic addition reactions compete with two electron reduction of quinones by sulphur dioxide or ascorbic acid, and both routes serve as effective quenching pathways, but minor secondary products from coupled redox reactions between the products and reactants are also observed. The wine preservatives were all highly reactive and thus all very protective against 3-sulfanylhexanol loss to the quinone, but showed only additive antioxidant effects. Confirmation of these reaction rates and pathways in wine is needed to assess the actual protective action of each tested preservative. Copyright © 2014 Elsevier Ltd. All rights reserved.

Quinones are growth factors for the human gut microbiota.

Science.gov (United States)

Fenn, Kathrin; Strandwitz, Philip; Stewart, Eric J; Dimise, Eric; Rubin, Sarah; Gurubacharya, Shreya; Clardy, Jon; Lewis, Kim

2017-12-20

The human gut microbiome has been linked to numerous components of health and disease. However, approximately 25% of the bacterial species in the gut remain uncultured, which limits our ability to properly understand, and exploit, the human microbiome. Previously, we found that growing environmental bacteria in situ in a diffusion chamber enables growth of uncultured species, suggesting the existence of growth factors in the natural environment not found in traditional cultivation media. One source of growth factors proved to be neighboring bacteria, and by using co-culture, we isolated previously uncultured organisms from the marine environment and identified siderophores as a major class of bacterial growth factors. Here, we employ similar co-culture techniques to grow bacteria from the human gut microbiome and identify novel growth factors. By testing dependence of slow-growing colonies on faster-growing neighboring bacteria in a co-culture assay, eight taxonomically diverse pairs of bacteria were identified, in which an "induced" isolate formed a gradient of growth around a cultivatable "helper." This set included two novel species Faecalibacterium sp. KLE1255-belonging to the anti-inflammatory Faecalibacterium genus-and Sutterella sp. KLE1607. While multiple helper strains were identified, Escherichia coli was also capable of promoting growth of all induced isolates. Screening a knockout library of E. coli showed that a menaquinone biosynthesis pathway was required for growth induction of Faecalibacterium sp. KLE1255 and other induced isolates. Purified menaquinones induced growth of 7/8 of the isolated strains, quinone specificity profiles for individual bacteria were identified, and genome analysis suggests an incomplete menaquinone biosynthetic capability yet the presence of anaerobic terminal reductases in the induced strains, indicating an ability to respire anaerobically. Our data show that menaquinones are a major class of growth factors for bacteria

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.

Quinone methides tethered to naphthalene diimides as selective G-quadruplex alkylating agents.

Science.gov (United States)

Di Antonio, Marco; Doria, Filippo; Richter, Sara N; Bertipaglia, Carolina; Mella, Mariella; Sissi, Claudia; Palumbo, Manlio; Freccero, Mauro

2009-09-16

We have developed novel G-quadruplex (G-4) ligand/alkylating hybrid structures, tethering the naphthalene diimide moiety to quaternary ammonium salts of Mannich bases, as quinone-methide precursors, activatable by mild thermal digestion (40 degrees C). The bis-substituted naphthalene diimides were efficiently synthesized, and their reactivity as activatable bis-alkylating agents was investigated in the presence of thiols and amines in aqueous buffered solutions. The electrophilic intermediate, quinone-methide, involved in the alkylation process was trapped, in the presence of ethyl vinyl ether, in a hetero Diels-Alder [4 + 2] cycloaddition reaction, yielding a substituted 2-ethoxychroman. The DNA recognition and alkylation properties of these new derivatives were investigated by gel electrophoresis, circular dichroism, and enzymatic assays. The alkylation process occurred preferentially on the G-4 structure in comparison to other DNA conformations. By dissecting reversible recognition and alkylation events, we found that the reversible process is a prerequisite to DNA alkylation, which in turn reinforces the G-quadruplex structural rearrangement.

Quinone 1 e ^– and 2 e ^– /2 H ⁺ Reduction Potentials: Identification and Analysis of Deviations from Systematic Scaling Relationships

Energy Technology Data Exchange (ETDEWEB)

Huynh, Mioy T.; Anson, Colin W.; Cavell, Andrew C.; Stahl, Shannon S.; Hammes-Schiffer, Sharon

2016-11-10

Quinones participate in diverse electron transfer and proton-coupled electron transfer processes in chemistry and biology. An experimental study of common quinones reveals a non-linear correlation between the 1 e^– and 2 e^–/2 H⁺ reduction potentials. This unexpected observation prompted a computational study of 128 different quinones, probing their 1 e^– reduction potentials, pKa values, and 2 e^–/2 H⁺ reduction potentials. The density functional theory calculations reveal an approximately linear correlation between these three properties and an effective Hammett constant associated with the quinone substituent(s). However, deviations from this linear scaling relationship are evident for quinones that feature halogen substituents, charged substituents, intramolecular hydrogen bonding in the hydroquinone, and/or sterically bulky substituents. These results, particularly the different substituent effects on the 1 e^– versus 2 e^– /2 H⁺ reduction potentials, have important implications for designing quinones with tailored redox properties.

Enzyme-Initiated Quinone-Chitosan Conjugation Chemistry: Toward A General in Situ Strategy for High-Throughput Photoelectrochemical Enzymatic Bioanalysis.

Science.gov (United States)

Wang, Guang-Li; Yuan, Fang; Gu, Tiantian; Dong, Yuming; Wang, Qian; Zhao, Wei-Wei

2018-02-06

Herein we report a general and novel strategy for high-throughput photoelectrochemical (PEC) enzymatic bioanalysis on the basis of enzyme-initiated quinone-chitosan conjugation chemistry (QCCC). Specifically, the strategy was illustrated by using a model quinones-generating oxidase of tyrosinase (Tyr) to catalytically produce 1,2-bezoquinone or its derivative, which can easily and selectively be conjugated onto the surface of the chitosan deposited PbS/NiO/FTO photocathode via the QCCC. Upon illumination, the covalently attached quinones could act as electron acceptors of PbS quantum dots (QDs), improving the photocurrent generation and thus allowing the elegant probing of Tyr activity. Enzyme cascades, such as alkaline phosphatase (ALP)/Tyr and β-galactosidase (Gal)/Tyr, were further introduced into the system for the successful probing of the corresponding targets. This work features not only the first use of QCCC in PEC bioanalysis but also the separation of enzymatic reaction from the photoelectrode as well as the direct signal recording in a split-type protocol, which enables quite convenient and high-throughput detection as compared to previous formats. More importantly, by using numerous other oxidoreductases that involve quinones as reactants/products, this protocol could serve as a common basis for the development of a new class of QCCC-based PEC enzymatic bioanalysis and further extended for general enzyme-labeled PEC bioanalysis of versatile targets.

An Inverse Electron Demand Azo-Diels-Alder Reaction of o-Quinone Methides and Imino Ethers: Synthesis of Benzocondensed 1,3-Oxazines.

Science.gov (United States)

Osipov, Dmitry V; Osyanin, Vitaly A; Khaysanova, Guzel' D; Masterova, Elvira R; Krasnikov, Pavel E; Klimochkin, Yuri N

2018-04-20

We have studied the reactions of o-quinone methide precursors with imino ethers. The reaction provides a versatile route to substituted 1,3-benzoxazines. The proposed reaction mechanism involves the generation of the o-quinone methide intermediates, imino-Diels-Alder reaction, and elimination. This cascade process is a rare example of the participation of imino ethers as dienophiles.

Are the reactions of quinones on graphite adiabatic?

International Nuclear Information System (INIS)

Luque, N.B.; Schmickler, W.

2013-01-01

Outer sphere electron transfer reactions on pure metal electrodes are often adiabatic and hence independent of the electrode material. Since it is not clear, whether adiabatic electron transfer can also occur on a semi-metal like graphite, we have re-investigated experimental data presented in a recent communication by Nissim et al. [Chemical Communications 48 (2012) 3294] on the reactions of quinones on graphite. We have supplemented their work by DFT calculations and conclude, that these reactions are indeed adiabatic. This contradicts the assertion of Nissim et al. that the rates are proportional to the density of states at the Fermi level

Liquid Quinones for Solvent-Free Redox Flow Batteries.

Science.gov (United States)

Shimizu, Akihiro; Takenaka, Keisuke; Handa, Naoyuki; Nokami, Toshiki; Itoh, Toshiyuki; Yoshida, Jun-Ichi

2017-11-01

Liquid benzoquinone and naphthoquinone having diethylene glycol monomethyl ether groups are designed and synthesized as redox active materials that dissolve supporting electrolytes. The Li-ion batteries based on the liquid quinones using LiBF 4 /PC show good performance in terms of voltage, capacity, energy efficiency, and cyclability in both static and flow modes. A battery is constructed without using intentionally added organic solvent, and its high energy density (264 W h L -1 ) demonstrates the potential of solvent-free organic redox flow batteries using liquid active materials. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Polychlorinated biphenyl quinone induces oxidative DNA damage and repair responses: The activations of NHEJ, BER and NER via ATM-p53 signaling axis

Energy Technology Data Exchange (ETDEWEB)

Dong, Hui; Shi, Qiong; Song, Xiufang; Fu, Juanli; Hu, Lihua; Xu, Demei; Su, Chuanyang; Xia, Xiaomin; Song, Erqun; Song, Yang, E-mail: songyangwenrong@hotmail.com

2015-07-01

Our previous studies demonstrated that polychlorinated biphenyl (PCB) quinone induced oxidative DNA damage in HepG2 cells. To promote genomic integrity, DNA damage response (DDR) coordinates cell-cycle transitions, DNA repair and apoptosis. PCB quinone-induced cell cycle arrest and apoptosis have been documented, however, whether PCB quinone insult induce DNA repair signaling is still unknown. In this study, we identified the activation of DDR and corresponding signaling events in HepG2 cells upon the exposure to a synthetic PCB quinone, PCB29-pQ. Our data illustrated that PCB29-pQ induces the phosphorylation of p53, which was mediated by ataxia telangiectasia mutated (ATM) protein kinase. The observed phosphorylated histone H2AX (γ-H2AX) foci and the elevation of 8-hydroxy-2′-deoxyguanosine (8-OHdG) indicated that DDR was stimulated by PCB29-pQ treatment. Additionally, we found PCB29-pQ activates non-homologous end joining (NHEJ), base excision repair (BER) and nucleotide excision repair (NER) signalings. However, these repair pathways are not error-free processes and aberrant repair of DNA damage may cause the potential risk of carcinogenesis and mutagenesis. - Highlights: • Polychlorinated biphenyl quinone induces oxidative DNA damage in HepG2 cells. • The elevation of γ-H2AX and 8-OHdG indicates the activation of DNA damage response. • ATM-p53 signaling acts as the DNA damage sensor and effector. • Polychlorinated biphenyl quinone activates NHEJ, BER and NER signalings.

Solid state oxidation of phenols to quinones with sodium perborate on wet montmorillonite K10

Energy Technology Data Exchange (ETDEWEB)

Hashemi, Mohammed M.; Eftekhari-Sis, Bagher; Khalili, Behzad; Karimi-Jaberi, Zahed [Sharif University of Technology, Tehran (Iran, Islamic Republic of). Dept. of Chemistry]. E-mail: mhashemi@sharif.edu

2005-09-15

Phenols were oxidized to quinones using sodium perborate (SPB) on wet montmorillonite as oxidant. The reaction was carried out at ambient temperature on the solid phase under solvent free conditions. (author)

Solid state oxidation of phenols to quinones with sodium perborate on wet montmorillonite K10

International Nuclear Information System (INIS)

Hashemi, Mohammed M.; Eftekhari-Sis, Bagher; Khalili, Behzad; Karimi-Jaberi, Zahed

2005-01-01

Phenols were oxidized to quinones using sodium perborate (SPB) on wet montmorillonite as oxidant. The reaction was carried out at ambient temperature on the solid phase under solvent free conditions. (author)

A prototype hybrid 7π quinone-fused 1,3,2-dithiazolyl radical.

Science.gov (United States)

Decken, A; Mailman, A; Passmore, J; Rautiainen, J M; Scherer, W; Scheidt, E-W

2011-01-28

Reaction of 1,4-naphthoquinone and SNSMF(6) (M = As, Sb) in SO(2) solution in a 1 : 2 molar ratio led to the naphthoquinone fused 1,3,2-dithiazolylium salts, 3MF(6) quantitatively by multinuclear NMR (87% isolated yield of 3SbF(6)) via the cycloaddition and oxidative dehydrogenation chemistry of SNS(+) with formation of NH(4)SbF(6) and S(8). The product 3SbF(6) was fully characterized by IR, Raman, multinuclear {(1)H, (13)C, (14)N} NMR, elemental analysis, cyclic voltammetry and single crystal X-ray crystallography. The reduction of 3SbF(6) with ferrocene (Cp(2)Fe) in refluxing acetonitrile (CH(3)CN) led to the first isolation of a fused quinone-thiazyl radical, 3˙ in 73% yield. The prototype hybrid quinone-thiazyl radical 3˙ was fully characterized by IR, Raman microscopy, EI-MS, elemental analysis, solution and solid state EPR, magnetic susceptibility (2-370 K) and was found to form π*-π* dimers in the solid state as determined by single crystal X-ray crystallography. Furthermore, the thermal decomposition of 3˙ led to a novel quinone-fused 1,2,3,4-tetrathiine, 10 (x = 2) and the known 1,2,5-thiadiazole, 11. The energetics of the cycloadditon and oxidative dehydrogenation chemistry of SNS(+) and 1,4-naphthoquinone leading to 3SbF(6) were estimated in the gas phase and SO(2) solution by DFT calculations (PBE0/6-311G(d)) and lattice enthalpies obtained by the volume based thermodynamic (VBT) approach in the solid state. The gas phase ion energetics (ionization potential (IP) and electron affinity (EA)) of 3˙ are compared to related 1,3,2- and 1,2,3-dithiazolyl radicals.

A physiological threshold for protection against menadione toxicity by human NAD(P)H : quinone oxidoreductase (NQO1) in Chinese hamster ovary (CHO) cells

NARCIS (Netherlands)

Haan, de L.H.J.; Boerboom, A.M.J.F.; Rietjens, I.M.C.M.; Capelle, van D.; Ruijter, de A.J.M.; Jaiswal, A.K.; Aarts, J.M.M.J.G.

2002-01-01

NAD(P)H:quinone oxidoreductase 1 (NQO1) has often been suggested to be involved in cancer prevention by means of detoxification of electrophilic quinones. In the present study, a series of Chinese hamster ovary (CHO) cell lines expressing various elevated levels of human NQO1 were generated by

Quinones as dienophiles in the Diels-Alder reaction: history and applications in total synthesis.

Science.gov (United States)

Nawrat, Christopher C; Moody, Christopher J

2014-02-17

In the canon of reactions available to the organic chemist engaged in total synthesis, the Diels-Alder reaction is among the most powerful and well understood. Its ability to rapidly generate molecular complexity through the simultaneous formation of two carbon-carbon bonds is almost unrivalled, and this is reflected in the great number of reported applications of this reaction. Historically, the use of quinones as dienophiles is highly significant, being the very first example investigated by Diels and Alder. Herein, we review the application of the Diels-Alder reaction of quinones in the total synthesis of natural products. The highlighted examples span some 60 years from the landmark syntheses of morphine (1952) and reserpine (1956) by Gates and Woodward, respectively, through to the present day examples, such as the tetracyclines. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Electrochemistry of potentially bioreductive alkylating quinones. Part 3. Quantitative structure-electrochemistry relationships of aziridinylquinones

NARCIS (Netherlands)

Driebergen, R.J.; Moret, E.E.; Janssen, L.H.M.; Blauw, J.S.; Holthuis, J.J.M.; Postma kelder, S.J.; Verboom, Willem; Reinhoudt, David; van der Linden, W.E.

1992-01-01

The concept of bioreductive alkylation as a mechanism of action of aziridinylquinoid anticancer agents has been investigated by the use of electrochemical techniques. Properly substituted aziridinylquinones are activated by an electrochemical step (reduction of the quinone function), followed by

Comparison of calculated and experimental isotope edited FTIR difference spectra for purple bacterial photosynthetic reaction centers with different quinones incorporated into the QA binding site.

Directory of Open Access Journals (Sweden)

Nan eZhao

2013-08-01

Full Text Available Previously we have shown that ONIOM type (QM/MM calculations can be used to simulate isotope edited FTIR difference spectra for neutral ubiquinone in the QA binding site in Rhodobacter sphaeroides photosynthetic reaction centers. Here we considerably extend upon this previous work by calculating isotope edited FTIR difference spectra for reaction centers with a variety of unlabeled and 18O labeled foreign quinones incorporated into the QA binding site. Isotope edited spectra were calculated for reaction centers with 2,3-dimethoxy-5,6-dimethyl-1,4-benzoquinone (MQ0, 2,3,5,6-tetramethyl-1,4-benzoquinone (duroquinone, DQ, and 2,3-dimethyl-l,4-naphthoquinone (DMNQ incorporated, and compared to corresponding experimental spectra. The calculated and experimental spectra agree well, further demonstrating the utility and applicability of our ONIOM approach for calculating the vibrational properties of pigments in protein binding sites.The normal modes that contribute to the bands in the calculated spectra, their composition, frequency and intensity, and how these quantities are modified upon 18O labeling, are presented. This computed information leads to a new and more detailed understanding/interpretation of the experimental FTIR difference spectra. Hydrogen bonding to the carbonyl groups of the incorporated quinones is shown to be relatively weak. It is also shown that there is some asymmetry in hydrogen bonding, accounting for 10-13 cm-1 separation in the frequencies of the carbonyl vibrational modes of the incorporated quinones. The extent of asymmetry H-bonding could only be established by considering the spectra for various types of quinones incorporated into the QA binding site. The quinones listed above are tail-less. Spectra were also calculated for reaction centers with corresponding tail containing quinones incorporated, and it is found that replacement of the quinone methyl group by a phytyl or prenyl chain does not alter ONIOM calculated s

In vivo relevance of two critical levels for NAD(P)H:quinone oxidoreductase (NQO1)-mediated cellular protection against electrophile toxicity found in vitro

NARCIS (Netherlands)

Haan, de L.H.J.; Pot, G.K.; Aarts, J.M.M.J.G.; Rietjens, I.M.C.M.; Alink, G.M.

2006-01-01

NAD(P)H:quinone oxidoreductase (NQO1)-mediated detoxification of quinones is suggested to be involved in cancer prevention. In the present study, using transfected CHO cells, it was demonstrated that the relation between NQO1 activity and the resulting protection against the cytotoxicity of

In-situ quartz crystal microgravimetric studies of molecular adsorbates containing thiol and hydroquinone moieties bound to Au(111) surfaces in aqueous electrolytes

Energy Technology Data Exchange (ETDEWEB)

Mo, Y.; Sukenik, C.; Sandifer, M. [Case Western Univ., Cleveland, OH (United States); Barriga, R.J.; Soriaga, M.P.; Scherson, D. [Texas A& M Univ., College Station, TX (United States)

1995-12-01

The microgravimetric properties of monolayers of 2, 5-dihydroxythiophenol, 2,5-dihydroxybenzyl mercaptan, and 2, 5-dihydroxy-4-methylbenzyl mercaptan adsorbed on Au(111) single crystal electrodes were examined by in situ quartz crystal microbalance techniques in aqueous perchloric acid electrolytes. The results obtained are consistent with the reversible loss of an average of about three waters per adsorbed molecule as the layers are oxidized and subsequently reduced. These observations provide evidence for discrete changes in the extent of bound water within the hydroquinone/quinone layer as the oxidation state of the monolayer is changed. 9 refs., 4 figs.

Atmospheric Distribution of PAHs and Quinones in the Gas and PM1 Phases in the Guadalajara Metropolitan Area, Mexico: Sources and Health Risk

Directory of Open Access Journals (Sweden)

Valeria Ojeda-Castillo

2018-04-01

Full Text Available Polycyclic aromatic hydrocarbons (PAHs and quinones in the gas phase and as submicron particles raise concerns due to their potentially carcinogenic and mutagenic properties. The majority of existing studies have investigated the formation of quinones, but it is also important to consider both the primary and secondary sources to estimate their contributions. The objectives of this study were to characterize PAHs and quinones in the gas and particulate matter (PM1 phases in order to identify phase distributions, sources, and cancer risk at two urban monitoring sites in the Guadalajara Metropolitan Area (GMA in Mexico. The simultaneous gas and PM1 phases samples were analyzed using a gas chromatography–mass spectrometer. The lifetime lung cancer risk (LCR due to PAH exposure was calculated to be 1.7 × 10−3, higher than the recommended risk value of 10−6, indicating a potential health hazard. Correlations between parent PAHs, criteria pollutants, and meteorological parameters suggest that primary sources are the main contributors to the Σ8 Quinones concentrations in PM1, while the secondary formation of 5,12-naphthacenequinone and 9,10-anthraquinone may contribute less to the observed concentration of quinones. Additionally, naphthalene, acenaphthene, fluorene, phenanthrene, and anthracene in PM1, suggest photochemical degradation into unidentified species. Further research is needed to determine how these compounds are formed.

Sustainable Innovation in Network-Bound Systems: Implications for the Consumption of Water, Waste Water and Electricity Services

NARCIS (Netherlands)

Vliet, van B.J.M.

2012-01-01

Network-bound systems are crucial in environmental governance as the usage of their services embody significant environmental impacts. Conditions for network-bound systems providing services to consumers have altered dramatically over the last decades. Liberalization and privatization have led to a

Effect of narcotics on membrane-bound mitochondrial processes in fish

DEFF Research Database (Denmark)

Vergauwen, Lucia; Nørgaard Schmidt, Stine; Michiels, Ellen

and endoplasmic reticulum membrane are known to closely interact with the cell membrane, we hypothesize that narcotics can be further partitioned into these organelle membranes where they can disrupt essential membrane-bound processes. The electron transport chain (ETC) is an example of a crucial mitochondrial...

Selective Alkylation of C-Rich Bulge Motifs in Nucleic Acids by Quinone Methide Derivatives.

Science.gov (United States)

Lönnberg, Tuomas; Hutchinson, Mark; Rokita, Steven

2015-09-07

A quinone methide precursor featuring a bis-cyclen anchoring moiety has been synthesized and its capacity to alkylate oligonucleotide targets quantified in the presence and absence of divalent metal ions (Zn(2+) , Ni(2+) and Cd(2+) ). The oligonucleotides were designed for testing the sequence and secondary structure specificity of the reaction. Gel electrophoretic analysis revealed predominant alkylation of C-rich bulges, regardless of the presence of divalent metal ions or even the bis-cyclen anchor. This C-selectivity appears to be an intrinsic property of the quinone methide electrophile as reflected by its reaction with an equimolar mixture of the 2'-deoxynucleosides. Only dA-N1 and dC-N3 alkylation products were detected initially and only the dC adduct persisted for detection under conditions of the gel electrophoretic analysis. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Beneficial synergistic effects of microdose lithium with pyrroloquinoline quinone in an Alzheimer's disease mouse model.

Science.gov (United States)

Zhao, Lei; Gong, Neng; Liu, Meng; Pan, Xiaoli; Sang, Shaoming; Sun, Xiaojing; Yu, Zhe; Fang, Qi; Zhao, Na; Fei, Guoqiang; Jin, Lirong; Zhong, Chunjiu; Xu, Tianle

2014-12-01

Alzheimer's disease (AD) is a complicated, neurodegenerative disorder involving multifactorial pathogeneses and still lacks effective clinical treatment. Recent studies show that lithium exerts disease-modifying effects against AD. However, the intolerant side effects at conventional effective dosage limit the clinical use of lithium in treating AD. To explore a novel AD treatment strategy with microdose lithium, we designed and synthesized a new chemical, tri-lithium pyrroloquinoline quinone (Li3PQQ), to study the synergistic effects of low-dose lithium and pyrroloquinoline quinone, a native compound with powerful antioxidation and mitochondrial amelioration. The results showed that Li3PQQ at a relative low dose (6 and 12 mg/kg) exhibited more powerful effects in restoring the impairment of learning and memory, facilitating hippocampal long-term potentiation, and reducing cerebral amyloid deposition and phosphorylated tau level in APP/PS1 transgenic mice than that of lithium chloride at both low and high dose (5 and 100 mg/kg). We further found that Li3PQQ inhibited the activity of glycogen synthase kinase-3 and increased the activity of β-amyloid-binding alcohol dehydrogenase, which might underlie the beneficial effects of Li3PQQ on APP/PS1 transgenic mice. Our study demonstrated the efficacy of a novel AD therapeutic strategy targeting at multiple disease-causing mechanisms through the synergistic effects of microdose lithium and pyrroloquinoline quinone. Copyright © 2014 Elsevier Inc. All rights reserved.

Exogenous quinones inhibit photosynthetic electron transfer in Chloroflexus aurantiacus by specific quenching of the excited bacteriochlorophyll c antenna

DEFF Research Database (Denmark)

Frigaard, N-U; Tokita, S; Matsuura, K

1999-01-01

In the photosynthetic green filamentous bacterium Chloroflexus aurantiacus, excitation energy is transferred from a large bacteriochlorophyll (BChl) c antenna via smaller BChl a antennas to the reaction center. The effects of substituted 1,4-naphthoquinones on BChl c and BChl a fluorescence and o...... antenna. Our results provide a model system for studying the redox-dependent antenna quenching in green sulfur bacteria because the antennas in these bacteria inherently exhibit a sensitivity to O(2) similar to the quinone-supplemented cells of Cfx. aurantiacus....... and on flash-induced cytochrome c oxidation were studied in whole cells under aerobic conditions. BChl c fluorescence in a cell suspension with 5.4 microM BChl c was quenched to 50% by addition of 0.6 microM shikonin ((R)-2-(1-hydroxy-4-methyl-3-pentenyl)-5,8-dihydroxy-1, 4-naphthoquinone), 0.9 microM 5......-hydroxy-1,4-naphthoquinone, or 4 microM 2-acetyl-3-methyl-1,4-naphthoquinone. Between 25 and 100 times higher quinone concentrations were needed to quench BChl a fluorescence to a similar extent. These quinones also efficiently inhibited flash-induced cytochrome c oxidation when BChl c was excited...

The Role of Human Aldo-Keto Reductases (AKRs in the Metabolic Activation and Detoxication of Polycyclic Aromatic Hydrocarbons: Interconversion of PAH-catechols and PAH o-Quinones

Directory of Open Access Journals (Sweden)

Li eZhang

2012-11-01

Full Text Available Polycyclic aromatic hydrocarbons (PAH are ubiquitous environmental pollutants. They are procarcinogens requiring metabolic activation to elicit their deleterious effects. Aldo-keto reductases (AKR catalyze the oxidation of proximate carcinogenic PAH trans-dihydrodiols to yield electrophilic and redox-active PAH o-quiniones. AKRs are also found to be capable of reducing PAH o-quinones to form PAH catechols. The interconversion of o-quinones and catechols results in the redox cycling of PAH o-quinones to give rise to the generation of reactive oxygen species and subsequent oxidative DNA damage. On the other hand, PAH catechols can be intercepted through phase II metabolism by which PAH o-quinones could be detoxified and eliminated. The aim of the present review is to summarize the role of human AKRs in the metabolic activation/detoxication of PAH and the relevance of phase II conjugation reactions to human lung carcinogenesis.

Electronic Connection Between the Quinone and Cytochrome c Redox Pools and Its Role in Regulation of Mitochondrial Electron Transport and Redox Signaling

Science.gov (United States)

Sarewicz, Marcin; Osyczka, Artur

2015-01-01

Mitochondrial respiration, an important bioenergetic process, relies on operation of four membranous enzymatic complexes linked functionally by mobile, freely diffusible elements: quinone molecules in the membrane and water-soluble cytochromes c in the intermembrane space. One of the mitochondrial complexes, complex III (cytochrome bc1 or ubiquinol:cytochrome c oxidoreductase), provides an electronic connection between these two diffusible redox pools linking in a fully reversible manner two-electron quinone oxidation/reduction with one-electron cytochrome c reduction/oxidation. Several features of this homodimeric enzyme implicate that in addition to its well-defined function of contributing to generation of proton-motive force, cytochrome bc1 may be a physiologically important point of regulation of electron flow acting as a sensor of the redox state of mitochondria that actively responds to changes in bioenergetic conditions. These features include the following: the opposing redox reactions at quinone catalytic sites located on the opposite sides of the membrane, the inter-monomer electronic connection that functionally links four quinone binding sites of a dimer into an H-shaped electron transfer system, as well as the potential to generate superoxide and release it to the intermembrane space where it can be engaged in redox signaling pathways. Here we highlight recent advances in understanding how cytochrome bc1 may accomplish this regulatory physiological function, what is known and remains unknown about catalytic and side reactions within the quinone binding sites and electron transfers through the cofactor chains connecting those sites with the substrate redox pools. We also discuss the developed molecular mechanisms in the context of physiology of mitochondria. PMID:25540143

Energetic change of the primary quinone in photosynthetic reaction center. Mutation, delayed fluorescence and model calculations (Theses of the Ph.D. dissertation)

International Nuclear Information System (INIS)

Rinyu, L.

2007-01-01

Complete text of publication follows. Photosynthesis is one of the basic metabolic processes of living organisms. Photosynthesizing species (bacteria, algae and higher class plants) convert the energy of light into other forms of free energy (redox potential, electro- chemical potential of ions and protons and phosphate-potential) which are directly suit- able either to cover the energy need of the vital processes of the cell or to storage. In reaction center (RC) protein of photo- synthetic bacteria, electron transfer is initiated upon light excitation from the excited bacteriochlorophyll dimer (P) to the secondary quinone (Q B ) via bacteriopheophytine (Bph) and the primary quinone (Q A ). In Rhodobacter sphaeroides purple bacteria, both quinones are ubiquinone-10, but due to the different protein environment, their electrochemical properties is highly different. Whereas Q A makes one-electron chemistry, Q B can be doubly reduced to form hydroquinone, Q B H 2 by uptake of two protons. Q B H 2 subsequently leaves the RC and is replaced by an oxidized quinone from to membrane pool. The semiquinones are important intermediates in the quinone reduction cycle of the RC. The redox midpoint potentials of the Q/Q - redox pairs (E m ) are also different: the Q A /Q A - has 60 mV more negative potential than the Q B /Q B - couple (pH 8) to make the (interquinone) electron transfer favorable. For fine tuning of the midpoint redox potentials of the quinones, the protein assures appropriate steric and electrostatic environment. The most important aim of this study was the design and production of reaction center mutants in the binding pocket of the primary quinone to investigate the effect of the amino acids of the protein and lipids of the membrane on the thermodynamics of the primary quinone. The first priority was the determination of the absolute free energy gap between the P* and the P + Q A - states in wild type and mutant reaction centers by comparison of the

Mechanisms of action of quinone-containing alkylating agents: DNA alkylation by aziridinylquinones.

Science.gov (United States)

Hargreaves, R H; Hartley, J A; Butler, J

2000-11-01

Aziridinyl quinones can be activated by cellular reductases eg. DT-diaphorase and cytochrome P450 reductase to form highly reactive DNA alkylating agents. The mechanisms by which this activation and alkylation take place are many and varied. Using clinically relevant and experimental agents this review will describe many of these mechanisms. The agents discussed are Mitomycin C, EO9 and analogues, diaziridinylbenzoquinones and the pyrrolo[1, 2-alpha]benzimidazolequinones.

Asp170 is crucial for the redox properties of vanillyl-alcohol oxidase

NARCIS (Netherlands)

Heuvel, van den R.H.H.; Fraaije, M.W.; Mattevi, A.; Berkel, van W.J.H.

2000-01-01

Vanillyl-alcohol oxidase is a flavoprotein containing a covalent flavin that catalyzes the oxidation of 4-(methoxymethyl)phenol to 4-hydroxybenzaldehyde. The reaction proceeds through the formation of a p-quinone methide intermediate, after which, water addition takes place. Asp-170, located near

Asp-170 Is Crucial for the Redox Properties of Vanillyl-alcohol Oxidase

NARCIS (Netherlands)

Heuvel, Robert H.H. van den; Fraaije, Marco W.; Mattevi, Andrea; Berkel, Willem J.H. van

2000-01-01

Vanillyl-alcohol oxidase is a flavoprotein containing a covalent flavin that catalyzes the oxidation of 4-(methoxymethyl)phenol to 4-hydroxybenzaldehyde. The reaction proceeds through the formation of a p-quinone methide intermediate, after which, water addition takes place. Asp-170, located near

Transient Kinetic Analysis of Hydrogen Sulfide Oxidation Catalyzed by Human Sulfide Quinone Oxidoreductase*

Science.gov (United States)

Mishanina, Tatiana V.; Yadav, Pramod K.; Ballou, David P.; Banerjee, Ruma

2015-01-01

The first step in the mitochondrial sulfide oxidation pathway is catalyzed by sulfide quinone oxidoreductase (SQR), which belongs to the family of flavoprotein disulfide oxidoreductases. During the catalytic cycle, the flavin cofactor is intermittently reduced by sulfide and oxidized by ubiquinone, linking H2S oxidation to the electron transfer chain and to energy metabolism. Human SQR can use multiple thiophilic acceptors, including sulfide, sulfite, and glutathione, to form as products, hydrodisulfide, thiosulfate, and glutathione persulfide, respectively. In this study, we have used transient kinetics to examine the mechanism of the flavin reductive half-reaction and have determined the redox potential of the bound flavin to be −123 ± 7 mV. We observe formation of an unusually intense charge-transfer (CT) complex when the enzyme is exposed to sulfide and unexpectedly, when it is exposed to sulfite. In the canonical reaction, sulfide serves as the sulfur donor and sulfite serves as the acceptor, forming thiosulfate. We show that thiosulfate is also formed when sulfide is added to the sulfite-induced CT intermediate, representing a new mechanism for thiosulfate formation. The CT complex is formed at a kinetically competent rate by reaction with sulfide but not with sulfite. Our study indicates that sulfide addition to the active site disulfide is preferred under normal turnover conditions. However, under pathological conditions when sulfite concentrations are high, sulfite could compete with sulfide for addition to the active site disulfide, leading to attenuation of SQR activity and to an alternate route for thiosulfate formation. PMID:26318450

Transient Kinetic Analysis of Hydrogen Sulfide Oxidation Catalyzed by Human Sulfide Quinone Oxidoreductase.

Science.gov (United States)

Mishanina, Tatiana V; Yadav, Pramod K; Ballou, David P; Banerjee, Ruma

2015-10-09

The first step in the mitochondrial sulfide oxidation pathway is catalyzed by sulfide quinone oxidoreductase (SQR), which belongs to the family of flavoprotein disulfide oxidoreductases. During the catalytic cycle, the flavin cofactor is intermittently reduced by sulfide and oxidized by ubiquinone, linking H2S oxidation to the electron transfer chain and to energy metabolism. Human SQR can use multiple thiophilic acceptors, including sulfide, sulfite, and glutathione, to form as products, hydrodisulfide, thiosulfate, and glutathione persulfide, respectively. In this study, we have used transient kinetics to examine the mechanism of the flavin reductive half-reaction and have determined the redox potential of the bound flavin to be -123 ± 7 mV. We observe formation of an unusually intense charge-transfer (CT) complex when the enzyme is exposed to sulfide and unexpectedly, when it is exposed to sulfite. In the canonical reaction, sulfide serves as the sulfur donor and sulfite serves as the acceptor, forming thiosulfate. We show that thiosulfate is also formed when sulfide is added to the sulfite-induced CT intermediate, representing a new mechanism for thiosulfate formation. The CT complex is formed at a kinetically competent rate by reaction with sulfide but not with sulfite. Our study indicates that sulfide addition to the active site disulfide is preferred under normal turnover conditions. However, under pathological conditions when sulfite concentrations are high, sulfite could compete with sulfide for addition to the active site disulfide, leading to attenuation of SQR activity and to an alternate route for thiosulfate formation. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Bound-state quark and gluon contributions to structure functions in QCD

International Nuclear Information System (INIS)

Brodsky, S.J.

1991-01-01

One can distinguish two types of contributions to the quark and gluon structure functions of hadrons in quantum chromodynamics: 'intrinsic' contributions, which are due to the direct scattering on the bound-state constituents, and 'extrinsic' contributions, which are derived from particles created in the collision. In this talk, I discuss several aspects of deep inealstic structure functions in which the bound-state structure of the proton plays a crucial role: (1) the properties of the intrinsic gluon distribution associated with the proton bound-state wavefunction; (2) the separation of the quark structure function of the proton into intrinsic 'bound-valence' and extrinsic 'non-valence' components which takes into account the Pauli principle; (3) the properties and identification of intrinsic heavy quark structure functions; and (4) a theory of shadowing and anti-shadowing of nuclear structure functions, directly related to quark-nucleon interactions and the gluon saturation phenomenon. (orig.)

Bound-state quark and gluon contributions to structure functions in QCD

International Nuclear Information System (INIS)

Brodsky, S.J.

1990-08-01

One can distinguish two types of contributions to the quark and gluon structure functions of hadrons in quantum chromodynamics: ''intrinsic'' contributions, which are due to the direct scattering on the bound-state constituents, and ''extrinsic'' contributions, which are derived from particles created in the collision. In this talk, I discussed several aspects of deep inelastic structure functions in which the bound-state structure of the proton plays a crucial role: the properties of the intrinsic gluon distribution associated with the proton bound-state wavefunction; the separation of the quark structure function of the proton onto intrinsic ''bound-valence'' and extrinsic ''non-valence'' components which takes into account the Pauli principle; the properties and identification of intrinsic heavy quark structure functions; and a theory of shadowing and anti-shadowing of nuclear structure functions, directly related to quark-nucleon interactions and the gluon saturation phenomenon. 49 refs., 5 figs

Quinones from plants of northeastern Brazil: structural diversity, chemical transformations, NMR data and biological activities.

Science.gov (United States)

Lemos, Telma L G; Monte, Francisco J Q; Santos, Allana Kellen L; Fonseca, Aluisio M; Santos, Hélcio S; Oliveira, Mailcar F; Costa, Sonia M O; Pessoa, Otilia D L; Braz-Filho, Raimundo

2007-05-20

The present review focus in quinones found in species of Brazilian northeastern Capraria biflora, Lippia sidoides, Lippia microphylla and Tabebuia serratifolia. The review cover ethnopharmacological aspects including photography of species, chemical structure feature, NMR datea and biological properties. Chemical transformations of lapachol to form enamine derivatives and biological activities are discussed.

Enhanced biotic and abiotic transformation of Cr(vi) by quinone-reducing bacteria/dissolved organic matter/Fe(iii) in anaerobic environment.

Science.gov (United States)

Huang, Bin; Gu, Lipeng; He, Huan; Xu, Zhixiang; Pan, Xuejun

2016-09-14

This study investigated the simultaneous transformation of Cr(vi) via a closely coupled biotic and abiotic pathway in an anaerobic system of quinone-reducing bacteria/dissolved organic matters (DOM)/Fe(iii). Batch studies were conducted with quinone-reducing bacteria to assess the influences of sodium formate (NaFc), electron shuttling compounds (DOM) and the Fe(iii) on Cr(vi) reduction rates as these chemical species are likely to be present in the environment during in situ bioremediation. Results indicated that the concentration of sodium formate and anthraquinone-2-sodium sulfonate (AQS) had apparently an effect on Cr(vi) reduction. The fastest decrease in rate for incubation supplemented with 5 mM sodium formate and 0.8 mM AQS showed that Fe(iii)/DOM significantly promoted the reduction of Cr(vi). Presumably due to the presence of more easily utilizable sodium formate, DOM and Fe(iii) have indirect Cr(vi) reduction capability. The coexisting cycles of Fe(ii)/Fe(iii) and DOM(ox)/DOM(red) exhibited a higher redox function than the individual cycle, and their abiotic coupling action can significantly enhance Cr(vi) reduction by quinone-reducing bacteria.

Dicumarol inhibition of NADPH:quinone oxidoreductase induces growth inhibition of pancreatic cancer via a superoxide-mediated mechanism.

Science.gov (United States)

Cullen, Joseph J; Hinkhouse, Marilyn M; Grady, Matthew; Gaut, Andrew W; Liu, Jingru; Zhang, Yu Ping; Weydert, Christine J Darby; Domann, Frederick E; Oberley, Larry W

2003-09-01

NADPH:quinone oxidoreductase (NQO(1)), a homodimeric, ubiquitous, flavoprotein, catalyzes the two-electron reduction of quinones to hydroquinones. This reaction prevents the one-electron reduction of quinones by cytochrome P450 reductase and other flavoproteins that would result in oxidative cycling with generation of superoxide (O(2)(.-)). NQO(1) gene regulation may be up-regulated in some tumors to accommodate the needs of rapidly metabolizing cells to regenerate NAD(+). We hypothesized that pancreatic cancer cells would exhibit high levels of this enzyme, and inhibiting it would suppress the malignant phenotype. Reverse transcription-PCR, Western blots, and activity assays demonstrated that NQO(1) was up-regulated in the pancreatic cancer cell lines tested but present in very low amounts in the normal human pancreas. To determine whether inhibition of NQO(1) would alter the malignant phenotype, MIA PaCa-2 pancreatic cancer cells were treated with a selective inhibitor of NQO(1), dicumarol. Dicumarol increased intracellular production of O(2)(.-), as measured by hydroethidine staining, and inhibited cell growth. Both of these effects were blunted with infection of an adenoviral vector containing the cDNA for manganese superoxide dismutase. Dicumarol also inhibited cell growth, plating efficiency, and growth in soft agar. We conclude that inhibition of NQO(1) increases intracellular O(2)(.-) production and inhibits the in vitro malignant phenotype of pancreatic cancer. These mechanisms suggest that altering the intracellular redox environment of pancreatic cancer cells may inhibit growth and delineate a potential strategy directed against pancreatic cancer.

Cytoskeleton and Cytoskeleton-Bound RNA Visualization in Frog and Insect Oocytes.

Science.gov (United States)

Kloc, Malgorzata; Bilinski, Szczepan; Kubiak, Jacek Z

2016-01-01

The majority of oocyte functions involves and depends on the cytoskeletal elements, which include microtubules and actin and cytokeratin filaments. Various structures and molecules are temporarily or permanently bound to the cytoskeletal elements and their functions rely on cytoskeleton integrity and its timely assembly. Thus the accurate visualization of cytoskeleton is often crucial for studies and analyses of oocyte structure and functions. Here we describe several reliable methods for microtubule and/or microfilaments preservation and visualization in Xenopus oocyte extracts, and in situ in live and fixed insect and frog (Xenopus) oocytes. In addition, we describe visualization of cytoskeleton-bound RNAs using molecular beacons in live Xenopus oocytes.

Differential stress-induced regulation of two quinone reductases in the brown rot Basidiomycete Gloeophyllum trabeum

Science.gov (United States)

Roni Cohen; Melissa R. Suzuki; Kenneth E. Hammel

2004-01-01

Quinone reductases (QRDs) have two important functions in the basidiomycete Gloeophyllum trabeum, which causes brown rot of wood. First, a QRD is required to generate biodegradative hydroxyl radicals via redox cycling between two G. trabeum extracellular metabolites, 2,5-dimethoxyhydroquinone (2,5-DMHQ) and 2,5-dimethoxy-1,4-benzoquinone (2,5- DMBQ). Second, because 2,...

Sustainable Innovation in Network-Bound Systems: Implications for the Consumption of Water, Waste Water and Electricity Services

OpenAIRE

Vliet, van, B.J.M.

2012-01-01

Network-bound systems are crucial in environmental governance as the usage of their services embody significant environmental impacts. Conditions for network-bound systems providing services to consumers have altered dramatically over the last decades. Liberalization and privatization have led to a differentiation in providers, technologies, products and services, very a-typical for sectors that were formerly characterized by public and uniform modes of provision and consumption. The paper gi...

Calcium mobilization by quinones and other free radical generating systems in rat hepatocytes

International Nuclear Information System (INIS)

Chen, E.C.; Chan, T.M.

1987-01-01

Using isolated rat hepatocytes, sublethal concentrations of quinones and other free radical generating systems were used to test the role of extracellular calcium (Ca) in activating glycogen phosphorylase and intracellular Ca mobilization. The α-agonist phenylephrine (Phe) was used for comparison. The EC50's were: Phe = 2.6 x 10 -7 M, menadione (K 3 ) = 4.5 x 10 -5 M, dicumarol = 2 x 10 -5 M. In normal Ca buffer, activation by K 3 was slower than Phe, being maximal at 2' but more sustained. Dicumarol and tert-butyl hydroperoxide (t-BH) activated phosphorylase similarly. The xanthine-xanthine oxidase (X-XO) system stimulated activation similar to K 3 . Dicumarol greatly augmented phosphorylase activation by K 3 but had no effect on Phe action. Depletion of extracellular Ca abolished Phe action, markedly diminished t-BH and dicumarol, but had no effect on K 3 or X-XO activation of phosphorylase. Ca efflux exchange measured in 45 Ca preloaded cells were stimulated equally by Phe, K 3 , dicumarol, or K 3 + dicumarol in the presence of extracellular Ca. Absence of extracellular Ca abolished Phe effect but minimally affected stimulation by K 3 or K 3 + dicumarol. These data suggest that activation of glycogen phosphorylase by sublethal doses of quinones may not reflect the degree and the mechanism of intracellular Ca mobilization

Redox-active quinones induces genome-wide DNA methylation changes by an iron-mediated and Tet-dependent mechanism

DEFF Research Database (Denmark)

Zhao, Bailin; Yang, Ying; Wang, Xiaoli

2014-01-01

DNA methylation has been proven to be a critical epigenetic mark important for various cellular processes. Here, we report that redox-active quinones, a ubiquitous class of chemicals found in natural products, cancer therapeutics and environment, stimulate the conversion of 5 mC to 5 hmC in vivo,...

Theoretical Bound of CRLB for Energy Efficient Technique of RSS-Based Factor Graph Geolocation

Science.gov (United States)

Kahar Aziz, Muhammad Reza; Heriansyah; Saputra, EfaMaydhona; Musa, Ardiansyah

2018-03-01

To support the increase of wireless geolocation development as the key of the technology in the future, this paper proposes theoretical bound derivation, i.e., Cramer Rao lower bound (CRLB) for energy efficient of received signal strength (RSS)-based factor graph wireless geolocation technique. The theoretical bound derivation is crucially important to evaluate whether the energy efficient technique of RSS-based factor graph wireless geolocation is effective as well as to open the opportunity to further innovation of the technique. The CRLB is derived in this paper by using the Fisher information matrix (FIM) of the main formula of the RSS-based factor graph geolocation technique, which is lied on the Jacobian matrix. The simulation result shows that the derived CRLB has the highest accuracy as a bound shown by its lowest root mean squared error (RMSE) curve compared to the RMSE curve of the RSS-based factor graph geolocation technique. Hence, the derived CRLB becomes the lower bound for the efficient technique of RSS-based factor graph wireless geolocation.

Vitamin E and vitamin E-quinone levels in red blood cells and plasma of newborn infants and their mothers.

Science.gov (United States)

Jain, S K; Wise, R; Bocchini, J J

1996-02-01

Vitamin E is a physiological antioxidant and protects cell membranes from oxidative damage. This study has determined whether vitamin E level in RBC of newborns has any relationship with its level in their mothers. We have also examined levels of vitamin E and vitamin E-quinone, an oxidized product of vitamin E, in paired samples of red blood cells (RBC) and plasma of newborns and their mothers. Blood was collected from 26 mothers and their full-term placental cords at delivery. Vitamin E and vitamin E-quinone levels were determined in RBC and plasma by HPLC. Newborn-plasma had significantly lower vitamin E levels compared with maternal-plasma both when expressed as nmole/ml (5.5+/-0.4 vs 26.1+/-1.1, p = 0.0001) or nmole/mumole total lipids (1.9+/-0.1 vs 2.6+/-0.1, p = 0.0001). Vitamin E level in the newborn-RBC was similar to that of maternal-RBC when expressed as nmole/ml packed cells (2.77+/-0.14 vs 2.95+/-0.13), but was significantly lower when expressed as nmole/mumole total lipids (0.56+/-0.03 vs 0.64+/-0.04, p = 0.03) from that of maternal-RBC. Vitamin E-quinone levels are significantly elevated in newborns compared with their mothers both in RBC (29.4+/-2.1 vs 24.1+/-1.2, p = 0.04) and plasma (39.9+/-5.3 vs 25.3+/-4.2, p = 0.006) when expressed as nmole/mmole total lipids but not when expressed as nmole/ml. There was a significant correlation of vitamin E between newborn-plasma and newborn-RBC (r = 0.65, p = 0.0002 for nmole per ml packed RBC;r = 0.63, p = 0.0007 for nmole per mumole total lipids). The relationship between maternal plasma and newborn plasma was significant when vitamin E was normalized with nmole/mumole total lipid (r = 0.54, p = 0.007 but not when expressed as nmole/ml (r = 0.09, p = 0.64). However, vitamin E in the RBC of maternal and newborn had significant correlation when expressed as per ml packed cells (r = 0.61, p = 0.001) and per total lipid (r = 0.46, p = 0.02). There was no relationship of vitamin E-quinone levels between RBC and

Identification of a multi-protein reductive dehalogenase complex in Dehalococcoides mccartyi strain CBDB1 suggests a protein-dependent respiratory electron transport chain obviating quinone involvement

DEFF Research Database (Denmark)

Kublik, Anja; Deobald, Darja; Hartwig, Stefanie

2016-01-01

electrophoresis (BN-PAGE), gel filtration and ultrafiltration an active dehalogenating protein complex with a molecular mass of 250–270 kDa was identified. The active subunit of reductive dehalogenase (RdhA) colocalised with a complex iron-sulfur molybdoenzyme (CISM) subunit (CbdbA195) and an iron-sulfur cluster...... of the dehalogenating complex prior to membrane solubilisation. Taken together, the identification of the respiratory dehalogenase protein complex and the absence of indications for quinone participation in the respiration suggest a quinone-independent protein-based respiratory electron transfer chain in D. mccartyi....

In vitro antifungal effect of black cumin seed quinones against dairy spoilage yeasts at different acidity levels.

Science.gov (United States)

Halamova, Katerina; Kokoska, Ladislav; Flesar, Jaroslav; Sklenickova, Olga; Svobodova, Blanka; Marsik, Petr

2010-12-01

The antiyeast activity of the black cumin seed (Nigella sativa) quinones dithymoquinone, thymohydroquinone (THQ), and thymoquinone (TQ) were evaluated in vitro with a broth microdilution method against six dairy spoilage yeast species. Antifungal effects of the quinones were compared with those of preservatives commonly used in milk products (calcium propionate, natamycin, and potassium sorbate) at two pH levels (4.0 and 5.5). THQ and TQ possessed significant antiyeast activity and affected the growth of all strains tested at both pH levels, with MICs ranging from 8 to 128 μg/ml. With the exception of the antibiotic natamycin, the inhibitory effects of all food preservatives against the yeast strains tested in this study were strongly affected by differences in pH, with MICs of ≥16 and ≥512 μg/ml at pH 4.0 and 5.5, respectively. These findings suggest that HQ and TQ are effective antiyeast agents that could be used in the dairy industry as chemical preservatives of natural origin.

Hydroquinone and quinone-grafted porous carbons for highly selective CO2 capture from flue gases and natural gas upgrading

NARCIS (Netherlands)

Wang, J.; Krishna, R.; Yang, J.; Deng, S.

2015-01-01

Hydroquinone and quinone functional groups were grafted onto a hierarchical porous carbon framework via the Friedel-Crafts reaction to develop more efficient adsorbents for the selective capture and removal of carbon dioxide from flue gases and natural gas. The oxygen-doped porous carbons were

Circuit lower bounds in bounded arithmetics

Czech Academy of Sciences Publication Activity Database

Pich, Ján

2015-01-01

Roč. 166, č. 1 (2015), s. 29-45 ISSN 0168-0072 R&D Projects: GA AV ČR IAA100190902 Keywords : bounded arithmetic * circuit lower bounds Subject RIV: BA - General Mathematics Impact factor: 0.582, year: 2015 http://www.sciencedirect.com/science/article/pii/S0168007214000888

Synthesis of α- and β-lapachone derivatives from hetero diels-alder trapping of alkyl and aryl o-quinone methides

International Nuclear Information System (INIS)

Silva, Fernando de C. da; Ferreira, Sabrina B.; Ferreira, Vitor F.; Kaiser, Carlos R.; Pinto, Angelo C.

2009-01-01

Methylene and aryl o-quinone methides (o-QMs) generated by Knoevenagel condensation of 2-hydroxy-1,4-naphthoquinone with formaldehyde and arylaldehydes, undergo facile hetero Diels-Alder reaction with some substituted styrenes (as dienophiles) in aqueous ethanol media providing derivatives of α- and β-lapachone (author)

Biosynthesis of actinorhodin and related antibiotics: discovery of alternative routes for quinone formation encoded in the act gene cluster.

Science.gov (United States)

Okamoto, Susumu; Taguchi, Takaaki; Ochi, Kozo; Ichinose, Koji

2009-02-27

All known benzoisochromanequinone (BIQ) biosynthetic gene clusters carry a set of genes encoding a two-component monooxygenase homologous to the ActVA-ORF5/ActVB system for actinorhodin biosynthesis in Streptomyces coelicolor A3(2). Here, we conducted molecular genetic and biochemical studies of this enzyme system. Inactivation of actVA-ORF5 yielded a shunt product, actinoperylone (ACPL), apparently derived from 6-deoxy-dihydrokalafungin. Similarly, deletion of actVB resulted in accumulation of ACPL, indicating a critical role for the monooxygenase system in C-6 oxygenation, a biosynthetic step common to all BIQ biosyntheses. Furthermore, in vitro, we showed a quinone-forming activity of the ActVA-ORF5/ActVB system in addition to that of a known C-6 monooxygenase, ActVA-ORF6, by using emodinanthrone as a model substrate. Our results demonstrate that the act gene cluster encodes two alternative routes for quinone formation by C-6 oxygenation in BIQ biosynthesis.

Kinetic, thermodynamic and X-ray structural insights into the interaction of melatonin and analogues with quinone reductase 2

Energy Technology Data Exchange (ETDEWEB)

Calamini, Barbara; Santarsiero, Bernard D.; Boutin, Jean A.; Mesecar, Andrew D. (IdRS); (UIC)

2008-09-12

Melatonin exerts its biological effects through at least two transmembrane G-protein-coupled receptors, MT1 and MT2, and a lower-affinity cytosolic binding site, designated MT3. MT3 has recently been identified as QR2 (quinone reductase 2) (EC 1.10.99.2) which is of significance since it links the antioxidant effects of melatonin to a mechanism of action. Initially, QR2 was believed to function analogously to QR1 in protecting cells from highly reactive quinones. However, recent studies indicate that QR2 may actually transform certain quinone substrates into more highly reactive compounds capable of causing cellular damage. Therefore it is hypothesized that inhibition of QR2 in certain cases may lead to protection of cells against these highly reactive species. Since melatonin is known to inhibit QR2 activity, but its binding site and mode of inhibition are not known, we determined the mechanism of inhibition of QR2 by melatonin and a series of melatonin and 5-hydroxytryptamine (serotonin) analogues, and we determined the X-ray structures of melatonin and 2-iodomelatonin in complex with QR2 to between 1.5 and 1.8 {angstrom} (1 {angstrom} = 0.1 nm) resolution. Finally, the thermodynamic binding constants for melatonin and 2-iodomelatonin were determined by ITC (isothermal titration calorimetry). The kinetic results indicate that melatonin is a competitive inhibitor against N-methyldihydronicotinamide (K{sub i} = 7.2 {mu}M) and uncompetitive against menadione (K{sub i} = 92 {mu}M), and the X-ray structures shows that melatonin binds in multiple orientations within the active sites of the QR2 dimer as opposed to an allosteric site. These results provide new insights into the binding mechanisms of melatonin and analogues to QR2.

Photocleavage of DNA: irradiation of quinone-containing reagents converts supercoiled to linear DNA

International Nuclear Information System (INIS)

Kock, T.; Schuster, G.B.; Ropp, J.D.; Sligar, S.G.

1993-01-01

Irradiation (350 nm) of air-saturated solutions of reagents containing an anthraquinone group linked to quaternary alkyl ammonium groups converts supercoiled DNA to circular and to linear DNA. Generation of linear DNA does not occur by accumulation of numerous single-strand cuts but by coincident-site double-strand cleavage of DNA. Irradiation forms the triplet state of the anthraquinone, which reacts either by hydrogen atom abstraction from a sugar of DNA or by electron transfer from a base of the DNA. Subsequent reactions result in chain scission. The quinone is apparently reformed after this sequence and reirradiation leads to double-strand cleavage. (Author)

Constituents of Musa x paradisiaca cultivar with the potential to induce the phase II enzyme, quinone reductase.

Science.gov (United States)

Jang, Dae Sik; Park, Eun Jung; Hawthorne, Michael E; Vigo, Jose Schunke; Graham, James G; Cabieses, Fernando; Santarsiero, Bernard D; Mesecar, Andrew D; Fong, Harry H S; Mehta, Rajendra G; Pezzuto, John M; Kinghorn, A Douglas

2002-10-23

A new bicyclic diarylheptanoid, rel-(3S,4aR,10bR)-8-hydroxy-3-(4-hydroxyphenyl)-9-methoxy-4a,5,6,10b-tetrahydro-3H-naphtho[2,1-b]pyran (1), as well as four known compounds, 1,2-dihydro-1,2,3-trihydroxy-9-(4-methoxyphenyl)phenalene (2), hydroxyanigorufone (3), 2-(4-hydroxyphenyl)naphthalic anhydride (4), and 1,7-bis(4-hydroxyphenyl)hepta-4(E),6(E)-dien-3-one (5), were isolated from an ethyl acetate-soluble fraction of the methanol extract of the fruits of Musa x paradisiaca cultivar, using a bioassay based on the induction of quinone reductase (QR) in cultured Hepa1c1c7 mouse hepatoma cells to monitor chromatographic fractionation. The structure and relative stereochemistry of compound 1 were elucidated unambiguously by one- and two-dimensional NMR experiments ((1)H NMR, (13)C NMR, DEPT, COSY, HMQC, HMBC, and NOESY) and single-crystal X-ray diffraction analysis. Isolates 1-5 were evaluated for their potential cancer chemopreventive properties utilizing an in vitro assay to determine quinone reductase induction and a mouse mammary organ culture assay.

Perceptron Mistake Bounds

OpenAIRE

Mohri, Mehryar; Rostamizadeh, Afshin

2013-01-01

We present a brief survey of existing mistake bounds and introduce novel bounds for the Perceptron or the kernel Perceptron algorithm. Our novel bounds generalize beyond standard margin-loss type bounds, allow for any convex and Lipschitz loss function, and admit a very simple proof.

Kinetic modeling of electron transfer reactions in photosystem I complexes of various structures with substituted quinone acceptors.

Science.gov (United States)

Milanovsky, Georgy E; Petrova, Anastasia A; Cherepanov, Dmitry A; Semenov, Alexey Yu

2017-09-01

The reduction kinetics of the photo-oxidized primary electron donor P 700 in photosystem I (PS I) complexes from cyanobacteria Synechocystis sp. PCC 6803 were analyzed within the kinetic model, which considers electron transfer (ET) reactions between P 700 , secondary quinone acceptor A 1 , iron-sulfur clusters and external electron donor and acceptors - methylviologen (MV), 2,3-dichloro-naphthoquinone (Cl 2 NQ) and oxygen. PS I complexes containing various quinones in the A 1 -binding site (phylloquinone PhQ, plastoquinone-9 PQ and Cl 2 NQ) as well as F X -core complexes, depleted of terminal iron-sulfur F A /F B clusters, were studied. The acceleration of charge recombination in F X -core complexes by PhQ/PQ substitution indicates that backward ET from the iron-sulfur clusters involves quinone in the A 1 -binding site. The kinetic parameters of ET reactions were obtained by global fitting of the P 700 + reduction with the kinetic model. The free energy gap ΔG 0 between F X and F A /F B clusters was estimated as -130 meV. The driving force of ET from A 1 to F X was determined as -50 and -220 meV for PhQ in the A and B cofactor branches, respectively. For PQ in A 1A -site, this reaction was found to be endergonic (ΔG 0  = +75 meV). The interaction of PS I with external acceptors was quantitatively described in terms of Michaelis-Menten kinetics. The second-order rate constants of ET from F A /F B , F X and Cl 2 NQ in the A 1 -site of PS I to external acceptors were estimated. The side production of superoxide radical in the A 1 -site by oxygen reduction via the Mehler reaction might comprise ≥0.3% of the total electron flow in PS I.

Electrochemical study of quinone redox cycling: A novel application of DNA-based biosensors for monitoring biochemical reactions.

Science.gov (United States)

Ensafi, Ali A; Jamei, Hamid Reza; Heydari-Bafrooei, Esmaeil; Rezaei, B

2016-10-01

This paper presents the results of an experimental investigation of voltammetric and impedimetric DNA-based biosensors for monitoring biological and chemical redox cycling reactions involving free radical intermediates. The concept is based on associating the amounts of radicals generated with the electrochemical signals produced, using differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS). For this purpose, a pencil graphite electrode (PGE) modified with multiwall carbon nanotubes and poly-diallydimethlammonium chloride decorated with double stranded fish sperm DNA was prepared to detect DNA damage induced by the radicals generated from a redox cycling quinone (i.e., menadione (MD; 2-methyl-1,4-naphthoquinone)). Menadione was employed as a model compound to study the redox cycling of quinones. A direct relationship was found between free radical production and DNA damage. The relationship between MD-induced DNA damage and free radical generation was investigated in an attempt to identify the possible mechanism(s) involved in the action of MD. Results showed that DPV and EIS were appropriate, simple and inexpensive techniques for the quantitative and qualitative comparisons of different reducing reagents. These techniques may be recommended for monitoring DNA damages and investigating the mechanisms involved in the production of redox cycling compounds. Copyright © 2016 Elsevier B.V. All rights reserved.

Pulse radiolytic and electrochemical investigations of intramolecular electron transfer in carotenoporphyrins and carotenoporphyrin-quinone triads

International Nuclear Information System (INIS)

Land, E.J.; Lexa, D.; Bensasson, R.V.; Gust, D.; Moore, T.A.; Moore, A.L.; Liddell, P.A.; Nemeth, G.A.

1987-01-01

Thermodynamic and kinetic aspects of intramolecular electron-transfer reactions in carotenoporphyrin dyads and carotenoid-porphyrin-quinone triads have been studied by using pulse radiolysis and cyclic voltammetry. Rapid (<1 μs) electron transfer from carotenoid radical anions to attached porphyrins has been inferred. Carotenoid cations, on the other hand, do not readily accept electrons from attached porphyrins or pyropheophorbides. Electrochemical studies provide the thermodynamic basis for these observations and also allow estimation of the energetics of photoinitiated two-step electron transfer and two-step charge recombination in triad models for photosynthetic charge separation

LC/MSMS STUDY OF BENZO[A]PYRENE-7,8-QUINONE ADDUCTION TO GLOBIN TRYPTIC PEPTIDES AND N-ACETYLAMINO ACIDS

Science.gov (United States)

Benzo[a]pyrene-7,8-quinone (BPQ) is regarded as a reactive genotoxic compound enzymatically formed from a xenobiotic precursor benzo[a]pyrene-7,8-diol by aldo-keto-reductase family of enzymes. Because BPQ, a Michael electrophile, was previously shown to react with oligonucleotide...

Virial Expansion Bounds

Science.gov (United States)

Tate, Stephen James

2013-10-01

In the 1960s, the technique of using cluster expansion bounds in order to achieve bounds on the virial expansion was developed by Lebowitz and Penrose (J. Math. Phys. 5:841, 1964) and Ruelle (Statistical Mechanics: Rigorous Results. Benjamin, Elmsford, 1969). This technique is generalised to more recent cluster expansion bounds by Poghosyan and Ueltschi (J. Math. Phys. 50:053509, 2009), which are related to the work of Procacci (J. Stat. Phys. 129:171, 2007) and the tree-graph identity, detailed by Brydges (Phénomènes Critiques, Systèmes Aléatoires, Théories de Jauge. Les Houches 1984, pp. 129-183, 1986). The bounds achieved by Lebowitz and Penrose can also be sharpened by doing the actual optimisation and achieving expressions in terms of the Lambert W-function. The different bound from the cluster expansion shows some improvements for bounds on the convergence of the virial expansion in the case of positive potentials, which are allowed to have a hard core.

Upper bounds on superpartner masses from upper bounds on the Higgs boson mass.

Science.gov (United States)

Cabrera, M E; Casas, J A; Delgado, A

2012-01-13

The LHC is putting bounds on the Higgs boson mass. In this Letter we use those bounds to constrain the minimal supersymmetric standard model (MSSM) parameter space using the fact that, in supersymmetry, the Higgs mass is a function of the masses of sparticles, and therefore an upper bound on the Higgs mass translates into an upper bound for the masses for superpartners. We show that, although current bounds do not constrain the MSSM parameter space from above, once the Higgs mass bound improves big regions of this parameter space will be excluded, putting upper bounds on supersymmetry (SUSY) masses. On the other hand, for the case of split-SUSY we show that, for moderate or large tanβ, the present bounds on the Higgs mass imply that the common mass for scalars cannot be greater than 10(11)  GeV. We show how these bounds will evolve as LHC continues to improve the limits on the Higgs mass.

The DMM Bound

DEFF Research Database (Denmark)

Emiris, Ioannis Z.; Mourrain, Bernard; Tsigaridas, Elias

2010-01-01

) resultant by means of mixed volume, as well as recent advances on aggregate root bounds for univariate polynomials, and are applicable to arbitrary positive dimensional systems. We improve upon Canny's gap theorem [7] by a factor of O(dn-1), where d bounds the degree of the polynomials, and n is the number...... bound on the number of steps that subdivision-based algorithms perform in order to isolate all real roots of a polynomial system. This leads to the first complexity bound of Milne's algorithm [22] in 2D....

Role of thiol homeostasis and adenine nucleotide metabolism in the protective effects of fructose in quinone-induced cytotoxicity in rat hepatocytes

NARCIS (Netherlands)

Toxopeus, C.; van Holsteijn, I.; de Winther, M. P.; van den Dobbelsteen, D.; Horbach, G. J.; Blaauboer, B. J.; Noordhoek, J.

1994-01-01

Freshly-isolated rat hepatocytes were exposed in glucose (15 mM) or fructose (5 mM) medium to menadione (2-methyl-1,4-naphthoquinone) (85 microM) or 1,4-naphthoquinone (NQ) (50 microM). Menadione and NQ are closely related quinones and have an approximately equal potential to induce redox cycling.

Tourism and Economic Growth in Sri Lanka: An ARDL Bounds Testing Approach

OpenAIRE

P. Srinivasan; Santhosh Kumar P. K; L. Ganesh

2012-01-01

The purpose of the study is to examine the impact of tourism on economic growth in Sri Lanka through the Autoregressive Distributed Lag (ARDL) bounds testing approach. The analysis was carried out for the period from 1969 to 2009. By and large, our analysis reveals that the tourism has a positive impact on economic growth in Sri Lanka both in the short-run and long-run. Hence, it is crucial for the Sri Lankan government to achieve unification and stability by focusing on political solutions t...

Towards a Certified Lightweight Array Bound Checker for Java Bytecode

Science.gov (United States)

Pichardie, David

2009-01-01

Dynamic array bound checks are crucial elements for the security of a Java Virtual Machines. These dynamic checks are however expensive and several static analysis techniques have been proposed to eliminate explicit bounds checks. Such analyses require advanced numerical and symbolic manipulations that 1) penalize bytecode loading or dynamic compilation, 2) complexify the trusted computing base. Following the Foundational Proof Carrying Code methodology, our goal is to provide a lightweight bytecode verifier for eliminating array bound checks that is both efficient and trustable. In this work, we define a generic relational program analysis for an imperative, stackoriented byte code language with procedures, arrays and global variables and instantiate it with a relational abstract domain as polyhedra. The analysis has automatic inference of loop invariants and method pre-/post-conditions, and efficient checking of analysis results by a simple checker. Invariants, which can be large, can be specialized for proving a safety policy using an automatic pruning technique which reduces their size. The result of the analysis can be checked efficiently by annotating the program with parts of the invariant together with certificates of polyhedral inclusions. The resulting checker is sufficiently simple to be entirely certified within the Coq proof assistant for a simple fragment of the Java bytecode language. During the talk, we will also report on our ongoing effort to scale this approach for the full sequential JVM.

Differential Privacy for Relational Algebra: Improving the Sensitivity Bounds via Constraint Systems

Directory of Open Access Journals (Sweden)

Catuscia Palamidessi

2012-07-01

Full Text Available Differential privacy is a modern approach in privacy-preserving data analysis to control the amount of information that can be inferred about an individual by querying a database. The most common techniques are based on the introduction of probabilistic noise, often defined as a Laplacian parametric on the sensitivity of the query. In order to maximize the utility of the query, it is crucial to estimate the sensitivity as precisely as possible. In this paper we consider relational algebra, the classical language for queries in relational databases, and we propose a method for computing a bound on the sensitivity of queries in an intuitive and compositional way. We use constraint-based techniques to accumulate the information on the possible values for attributes provided by the various components of the query, thus making it possible to compute tight bounds on the sensitivity.

Chemical modification of the lectin of the marine coral Gerardia savaglia by marine quinone avarone

Directory of Open Access Journals (Sweden)

IVANA PAJIC

2007-12-01

Full Text Available The quinone avarone, isolated from the marine sponge Dysidea avara, possesses the ability to chemically modify proteins. In this work, modification of lectin isolated from the coral Gerardia savaglia by avarone was examined. The techniques used for studying the modification were: SDS PAGE, isoelectric focusing and hemagglutination testing. The results of the SDS PAGE indicate dimerization of the protein. A shift of the pI toward lower value occurs upon modification. The change of the hemagglutination activity of the protein confirms that chemical modification of G. savaglia lectin by avarone changes its ability to interact with the membrane of erythrocytes.

Chemoselective Methylation of Phenolic Hydroxyl Group Prevents Quinone Methide Formation and Repolymerization During Lignin Depolymerization

Energy Technology Data Exchange (ETDEWEB)

Kim, Kwang Ho; Dutta, Tanmoy; Walter, Eric D.; Isern, Nancy G.; Cort, John R.; Simmons, Blake A.; Singh, Seema

2017-03-30

Chemoselective blocking of the phenolic hydroxyl (Ar-OH) group by methylation was found to suppress secondary repolymerization and charring during lignin depolymerization. Methylation of Ar-OH prevents formation of reactive quinone methide intermediates, which are partly responsible for undesirable secondary repolymerization reactions. Instead, this structurally modified lignin produces more relatively low molecular weight products from lignin depolymerization compared to unmodified lignin. This result demonstrates that structural modification of lignin is desirable for production of low molecular weight phenolic products. This approach could be directed toward alteration of natural lignification processes to produce biomass more amenable to chemical depolymerization.

Organically bound tritium

International Nuclear Information System (INIS)

Diabate, S.; Strack, S.

1993-01-01

Tritium released into the environment may be incorporated into organic matter. Organically bound tritium in that case will show retention times in organisms that are considerably longer than those of tritiated water which has significant consequences on dose estimates. This article reviews the most important processes of organically bound tritium production and transport through food networks. Metabolic reactions in plant and animal organisms with tritiated water as a reaction partner are of great importance in this respect. The most important production process, in quantitative terms, is photosynthesis in green plants. The translocation of organically bound tritium from the leaves to edible parts of crop plants should be considered in models of organically bound tritium behavior. Organically bound tritium enters the human body on several pathways, either from the primary producers (vegetable food) or at a higher tropic level (animal food). Animal experiments have shown that the dose due to ingestion of organically bound tritium can be up to twice as high as a comparable intake of tritiated water in gaseous or liquid form. In the environment, organically bound tritium in plants and animals is often found to have higher specific tritium concentrations than tissue water. This is not due to some tritium enrichment effects but to the fact that no equilibrium conditions are reached under natural conditions. 66 refs

Physical Uncertainty Bounds (PUB)

Energy Technology Data Exchange (ETDEWEB)

Vaughan, Diane Elizabeth [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Preston, Dean L. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2015-03-19

This paper introduces and motivates the need for a new methodology for determining upper bounds on the uncertainties in simulations of engineered systems due to limited fidelity in the composite continuum-level physics models needed to simulate the systems. We show that traditional uncertainty quantification methods provide, at best, a lower bound on this uncertainty. We propose to obtain bounds on the simulation uncertainties by first determining bounds on the physical quantities or processes relevant to system performance. By bounding these physics processes, as opposed to carrying out statistical analyses of the parameter sets of specific physics models or simply switching out the available physics models, one can obtain upper bounds on the uncertainties in simulated quantities of interest.

Role of NAD(P)H:quinone oxidoreductase 1 in clofibrate-mediated hepatoprotection from acetaminophen

International Nuclear Information System (INIS)

Moffit, Jeffrey S.; Aleksunes, Lauren M.; Kardas, Michael J.; Slitt, Angela L.; Klaassen, Curtis D.; Manautou, Jose E.

2007-01-01

Mice pretreated with the peroxisome proliferator clofibrate (CFB) are resistant to acetaminophen (APAP) hepatotoxicity. Whereas the mechanism of protection is not entirely known, CFB decreases protein adducts formed by the reactive metabolite of APAP, N-acetyl-p-benzoquinone imine (NAPQI). NAD(P)H:quinone oxidoreductase 1 (NQO1) is an enzyme with antioxidant properties that is responsible for the reduction of cellular quinones. We hypothesized that CFB increases NQO1 activity, which in turn enhances the conversion of NAPQI back to the parent APAP. This could explain the decreases in APAP covalent binding and glutathione depletion produced by CFB without affecting APAP bioactivation to NAPQI. Administration of CFB (500 mg/kg, i.p.) to male CD-1 mice for 5 or 10 days increased NQO1 protein and activity levels. To evaluate the capacity of NQO1 to reduce NAPQI back to APAP, we utilized a microsomal activating system. Cytochrome P450 enzymes present in microsomes bioactivate APAP to NAPQI, which binds the electrophile trapping agent, N-acetyl cysteine (NAC). We analyzed the formation of APAP-NAC metabolite in the presence of human recombinant NQO1. Results indicate that NQO1 is capable of reducing NAPQI. The capacity of NQO1 to amelioriate APAP toxicity was then evaluated in primary hepatocytes. Primary hepatocytes isolated from mice dosed with CFB are resistant to APAP toxicity. These hepatocytes were also exposed to ES936, a high affinity, and irreversible inhibitor of NQO1 in the presence of APAP. Concentrations of ES936 that resulted in over 94% inhibition of NQO1 activity did not increase the susceptibility of hepatocytes from CFB treated mice to APAP. Whereas NQO1 is mechanistically capable of reducing NAPQI, CFB-mediated hepatoprotection does not appear to be dependent upon enhanced expression of NQO1

Supercritical fluid extraction and ultra performance liquid chromatography of respiratory quinones for microbial community analysis in environmental and biological samples.

Science.gov (United States)

Hanif, Muhammad; Atsuta, Yoichi; Fujie, Koichi; Daimon, Hiroyuki

2012-03-05

Microbial community structure plays a significant role in environmental assessment and animal health management. The development of a superior analytical strategy for the characterization of microbial community structure is an ongoing challenge. In this study, we developed an effective supercritical fluid extraction (SFE) and ultra performance liquid chromatography (UPLC) method for the analysis of bacterial respiratory quinones (RQ) in environmental and biological samples. RQ profile analysis is one of the most widely used culture-independent tools for characterizing microbial community structure. A UPLC equipped with a photo diode array (PDA) detector was successfully applied to the simultaneous determination of ubiquinones (UQ) and menaquinones (MK) without tedious pretreatment. Supercritical carbon dioxide (scCO(2)) extraction with the solid-phase cartridge trap proved to be a more effective and rapid method for extracting respiratory quinones, compared to a conventional organic solvent extraction method. This methodology leads to a successful analytical procedure that involves a significant reduction in the complexity and sample preparation time. Application of the optimized methodology to characterize microbial communities based on the RQ profile was demonstrated for a variety of environmental samples (activated sludge, digested sludge, and compost) and biological samples (swine and Japanese quail feces).

Supercritical Fluid Extraction and Ultra Performance Liquid Chromatography of Respiratory Quinones for Microbial Community Analysis in Environmental and Biological Samples

OpenAIRE

Hanif, Muhammad; Atsuta, Yoichi; Fujie, Koichi; Daimon, Hiroyuki

2012-01-01

Microbial community structure plays a significant role in environmental assessment and animal health management. The development of a superior analytical strategy for the characterization of microbial community structure is an ongoing challenge. In this study, we developed an effective supercritical fluid extraction (SFE) and ultra performance liquid chromatography (UPLC) method for the analysis of bacterial respiratory quinones (RQ) in environmental and biological samples. RQ profile analysi...

78 FR 18326 - Agency Information Collection Activities; Comment Request; Upward Bound and Upward Bound Math...

Science.gov (United States)

2013-03-26

...; Comment Request; Upward Bound and Upward Bound Math Science Annual Performance Report AGENCY: The Office... considered public records. Title of Collection: Upward Bound and Upward Bound Math Science Annual Performance...) and Upward Bound Math and Science (UBMS) Programs. The Department is requesting a new APR because of...

A Hierarchically Porous Hypercrosslinked and Novel Quinone based Stable Organic Polymer Electrode for Lithium-Ion Batteries

International Nuclear Information System (INIS)

Ahmad, Aziz; Meng, Qinghai; Melhi, Saad; Mao, Lijuan; Zhang, Miao; Han, Bao-Hang; Lu, Kun; Wei, Zhixiang

2017-01-01

Highlights: •A novel hypercrosslinked Poly-Pillar[5]quinone (Poly-P5Q) polymer has been prepared and applied as electrode material in Li-ion batteries. •The novel synthetic route of Poly-P5Q was introduced by the oxidation of Poly-Dimethoxypillar[5]arene. •A Friedel-Crafts reaction was employed to prepare a novel Poly-P5Q as organic cathode material for lithium-ion batteries. -- Abstract: In the recent years, organic electrode materials have attracted tremendous attention and becoming promising electrode candidates for the green and sustainable lithium-ion batteries. A novel hypercrosslinked Poly-Pillar[5]quinone (Poly-P5Q) polymer was prepared and applied as electrode material in Li-ion batteries. Poly-P5Q is the oxidized form of Poly-Dimethoxypillar[5]arene (Poly-DMP5A) which was obtained from the condensation of dimethoxypillar[5]arene and formaldehyde dimethyl acetal using Friedel-Crafts reaction. The prepared materials were characterized by 13 C solid state NMR, FTIR, SEM, EDX and TGA analysis. The Poly-P5Q cathode showed an initial discharge capacity up to 105 mAh g −1 whereas it retained 82.3% of its initial discharge capacity after 100 charge-discharge cycles at a current speed of 100 mA g −1 in the potential window between 1.75 to 3.25 V. In future, research in this direction will provide great insight for the development of novel polymers from various small organic molecules as a stable and high performance electrode materials for green lithium-ion batteries.

Universal bounds on current fluctuations.

Science.gov (United States)

Pietzonka, Patrick; Barato, Andre C; Seifert, Udo

2016-05-01

For current fluctuations in nonequilibrium steady states of Markovian processes, we derive four different universal bounds valid beyond the Gaussian regime. Different variants of these bounds apply to either the entropy change or any individual current, e.g., the rate of substrate consumption in a chemical reaction or the electron current in an electronic device. The bounds vary with respect to their degree of universality and tightness. A universal parabolic bound on the generating function of an arbitrary current depends solely on the average entropy production. A second, stronger bound requires knowledge both of the thermodynamic forces that drive the system and of the topology of the network of states. These two bounds are conjectures based on extensive numerics. An exponential bound that depends only on the average entropy production and the average number of transitions per time is rigorously proved. This bound has no obvious relation to the parabolic bound but it is typically tighter further away from equilibrium. An asymptotic bound that depends on the specific transition rates and becomes tight for large fluctuations is also derived. This bound allows for the prediction of the asymptotic growth of the generating function. Even though our results are restricted to networks with a finite number of states, we show that the parabolic bound is also valid for three paradigmatic examples of driven diffusive systems for which the generating function can be calculated using the additivity principle. Our bounds provide a general class of constraints for nonequilibrium systems.

Role of the NAD(P)H quinone oxidoreductase NQR and the cytochrome b AIR12 in controlling superoxide generation at the plasma membrane.

Science.gov (United States)

Biniek, Catherine; Heyno, Eiri; Kruk, Jerzy; Sparla, Francesca; Trost, Paolo; Krieger-Liszkay, Anja

2017-04-01

The quinone reductase NQR and the b-type cytochrome AIR12 of the plasma membrane are important for the control of reactive oxygen species in the apoplast. AIR12 and NQR are two proteins attached to the plant plasma membrane which may be important for generating and controlling levels of reactive oxygen species in the apoplast. AIR12 (Auxin Induced in Root culture) is a single gene of Arabidopsis that codes for a mono-heme cytochrome b. The NADPH quinone oxidoreductase NQR is a two-electron-transferring flavoenzyme that contributes to the generation of O 2 •- in isolated plasma membranes. A. thaliana double knockout plants of both NQR and AIR12 generated more O 2 •- and germinated faster than the single mutant affected in AIR12. To test whether NQR and AIR12 are able to interact functionally, recombinant purified proteins were added to plasma membranes isolated from soybean hypocotyls. In vitro NADH-dependent O 2 •- production at the plasma membrane in the presence of NQR was reduced upon addition of AIR12. Electron donation from semi-reduced menadione to AIR12 was shown to take place. Biochemical analysis showed that purified plasma membrane from soybean hypocotyls or roots contained phylloquinone and menaquinone-4 as redox carriers. This is the first report on the occurrence of menaquinone-4 in eukaryotic photosynthetic organisms. We propose that NQR and AIR12 interact via the quinone, allowing an electron transfer from cytosolic NAD(P)H to apoplastic monodehydroascorbate and control thereby the level of reactive oxygen production and the redox state of the apoplast.

Comparative toxicity of eugenol and its quinone methide metabolite in cultured liver cells using kinetic fluorescence bioassays.

Science.gov (United States)

Thompson, D C; Barhoumi, R; Burghardt, R C

1998-03-01

Comparative kinetic analyses of the mechanisms of toxicity of the alkylphenol eugenol and its putative toxic metabolite (quinone methide, EQM) were carried out in cultured rat liver cells (Clone 9, ATCC) using a variety of vital fluorescence bioassays with a Meridian Ultima laser cytometer. Parameters monitored included intracellular GSH and calcium levels ([Ca2+]i), mitochondrial and plasma membrane potentials (MMP and PMP), intracellular pH, reactive oxygen species (ROS) generation, and gap junction-mediated intercellular communication (GJIC). Cells were exposed to various concentrations of test compounds (1 to 1000 microM) and all parameters monitored directly after addition at 15 s intervals for at least 10 min. Eugenol depleted intracellular GSH, inhibited GJIC and generation of ROS, and had a modest effect on MMP at concentrations of 10 to 100 microM. At high concentrations (1000 microM), eugenol also affected [Ca2+]i, PMP, and pH. Effects of EQM were seen at lower concentrations (1 to 10 microM). The earliest and most potent effects of either eugenol or EQM were seen on GSH levels and GJIC. Coadministration of glutathione ethyl ester enhanced intracellular GSH levels by almost 100% and completely protected cells from cell death caused by eugenol and EQM. These results suggest that eugenol mediates its hepatotoxic effects primarily through depletion of cytoprotective thiols and interference in thiol-dependent processes such as GJIC. Furthermore, our results support the hypothesis that the toxic effects of eugenol are mediated through its quinone methide metabolite.

Quivers of Bound Path Algebras and Bound Path Coalgebras

Directory of Open Access Journals (Sweden)

Dr. Intan Muchtadi

2010-09-01

Full Text Available bras and coalgebras can be represented as quiver (directed graph, and from quiver we can construct algebras and coalgebras called path algebras and path coalgebras. In this paper we show that the quiver of a bound path coalgebra (resp. algebra is the dual quiver of its bound path algebra (resp. coalgebra.

Channelling phenomenon in the gamma irradiated Benzo-quinone and other compounds observed under the scanning electron microscope

International Nuclear Information System (INIS)

Suleiman, Y.M.

1984-01-01

Scanning Electron Microscope (S.E.M.), has been used to examine the gamma irradiated pure crystals of Benzo-quinone and other compounds in the polycrystaline form. After gamma irradiation, shallow lines (channels) were observed on the crystal's surfaces when the crystal layers arrangements are parallel to the photons beam direction. Holes were also observed when those layers of the crystals are in the nonparallel case. The phenomenon has been studied and analysed in connected with the H-atom bonds disruption, and H-atoms migration through the crystal's layers. (author)

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.

Photon virtual bound state

International Nuclear Information System (INIS)

Inoue, J.; Ohtaka, K.

2004-01-01

We study virtual bound states in photonics, which are a vectorial extension of electron virtual bound states. The condition for these states is derived. It is found that the Mie resonant state which satisfies the condition that the size parameter is less than the angular momentum should be interpreted as a photon virtual bound state. In order to confirm the validity of the concept, we compare the photonic density of states, the width of which represents the lifetime of the photon virtual bound states, with numerical results

Resignation syndrome: Catatonia? Culture-bound?

Directory of Open Access Journals (Sweden)

Karl eSallin

2016-01-01

Full Text Available Resignation syndrome (RS designates a long-standing disorder predominately affecting psychologically traumatised children and adolescents in the midst of a strenuous and lengthy migration process. Typically a depressive onset is followed by gradual withdrawal progressing via stupor into a state that prompts tube feeding and is characterised by failure to respond even to painful stimuli. The patient is seemingly unconscious. Recovery ensues within months to years and is claimed to be dependent on the restoration of hope to the family.Descriptions of disorders resembling RS can be found in the literature and the condition is unlikely novel. Nevertheless, the magnitude and geographical distribution stand out. Several hundred cases have been reported exclusively in Sweden in the past decade prompting the Swedish National Board of Health and Welfare to recognise RS as a separate diagnostic entity. The currently prevailing stress hypothesis fails to account for the regional distribution and contributes little to treatment. Consequently, a re-evaluation of diagnostics and treatment is required. Psychogenic catatonia is proposed to supply the best fit with the clinical presentation. Treatment response, altered brain metabolism or preserved awareness would support this hypothesis.Epidemiological data suggests culture-bound beliefs and expectations to generate and direct symptom expression and we argue that culture-bound psychogenesis can accommodate the endemic distribution.Last, we review recent models of predictive coding indicating how expectation processes are crucially involved in the placebo and nocebo effect, delusions and conversion disorders. Building on this theoretical framework we propose a neurobiological model of RS in which the impact of overwhelming negative expectations are directly causative of the down-regulation of higher order and lower order behavioural systems in particularly vulnerable individuals.

Supercritical Fluid Extraction and Ultra Performance Liquid Chromatography of Respiratory Quinones for Microbial Community Analysis in Environmental and Biological Samples

Directory of Open Access Journals (Sweden)

Koichi Fujie

2012-03-01

Full Text Available Microbial community structure plays a significant role in environmental assessment and animal health management. The development of a superior analytical strategy for the characterization of microbial community structure is an ongoing challenge. In this study, we developed an effective supercritical fluid extraction (SFE and ultra performance liquid chromatography (UPLC method for the analysis of bacterial respiratory quinones (RQ in environmental and biological samples. RQ profile analysis is one of the most widely used culture-independent tools for characterizing microbial community structure. A UPLC equipped with a photo diode array (PDA detector was successfully applied to the simultaneous determination of ubiquinones (UQ and menaquinones (MK without tedious pretreatment. Supercritical carbon dioxide (scCO2 extraction with the solid-phase cartridge trap proved to be a more effective and rapid method for extracting respiratory quinones, compared to a conventional organic solvent extraction method. This methodology leads to a successful analytical procedure that involves a significant reduction in the complexity and sample preparation time. Application of the optimized methodology to characterize microbial communities based on the RQ profile was demonstrated for a variety of environmental samples (activated sludge, digested sludge, and compost and biological samples (swine and Japanese quail feces.

Origin of the Giant Honeycomb Network of Quinones on Cu(111)

Science.gov (United States)

Einstein, T. L.; Kim, Kwangmoo; Wyrick, Jon; Cheng, Zhihai; Bartels, Ludwig; Berland, Kristian; Hyldgaard, Per

2011-03-01

We discuss the factors that lead to the amazing regular giant honeycomb network formed by quinones on Cu(111). Using a related lattice gas model with many characteristic energies, we can reproduce many experimental features. These models require a long-range attraction, which can be attributed to indirect interactions mediated by the Shockley surface state of Cu(111). However, Wyrick's preceding talk gave evidence that the network self-selects for the size of the pore rather than for the periodicity of the superstructure, suggesting that confined states are the key ingredient. We discuss this phenomenon in terms of the magic numbers of 2D quantum dots. We also report calculations of the effects of anthraquinones (AQ) in modifying the surface states by considering a superlattice of AQ chains with various separations. We discuss implications of these results for tuning the electronic states and, thence, superstructures. Supported by (TLE) NSF CHE 07-50334 & UMD MRSEC DMR 05-20471, (JW & LB) NSF CHE NSF CHE 07-49949, (KB & PH) Swedish Vetenskapsrådet VR 621-2008-4346.

Ebselen: A thioredoxin reductase-dependent catalyst for α-tocopherol quinone reduction

International Nuclear Information System (INIS)

Fang Jianguo; Zhong Liangwei; Zhao Rong; Holmgren, Arne

2005-01-01

The thioredoxin system, composed of thioredoxin (Trx), thioredoxin reductase (TrxR), and NADPH, is a powerful protein disulfide reductase system with a broad substrate specificity. Recently the selenazol drug ebselen was shown to be a substrate for both mammalian TrxR and Trx. We examined if α-tocopherol quinone (TQ), a product of α-tocopherol oxidation, is reduced by ebselen in the presence of TrxR, since TQ was not a substrate for the enzyme itself. Ebselen reduction of TQ in the presence of TrxR was caused by ebselen selenol, generated from fast reduction of ebselen by the enzyme. TQ has no intrinsic antioxidant activity, while the product of reduction of TQ, α-tocopherolhydroquinone (TQH 2 ), is a potent antioxidant. The thioredoxin system dependence of ebselen to catalyze reduction of other oxidized species, such as hydrogen peroxide, dehydroascorbate, and peroxynitrite, is discussed. The ability of ebselen to reduce TQ via the thioredoxin system is a novel mechanism to explain the effects of the drug as an antioxidant in vivo

Regulation of expression of Na+ -translocating NADH:quinone oxidoreductase genes in Vibrio harveyi and Klebsiella pneumoniae.

Science.gov (United States)

Fadeeva, Maria S; Yakovtseva, Evgenia A; Belevich, Galina A; Bertsova, Yulia V; Bogachev, Alexander V

2007-10-01

The expression of genes encoding sodium-translocating NADH:quinone oxidoreductase (Na(+)-NQR) was studied in the marine bacterium Vibrio harveyi and in the enterobacterium Klebsiella pneumoniae. It has been shown that such parameters as NaCl concentration, pH value, and presence of an uncoupler in the growth media do not influence significantly the level of nqr expression. However, nqr expression depends on the growth substrates used by these bacteria. Na(+)-NQR is highly repressed in V. harveyi during anaerobic growth, and nqr expression is modulated by electron acceptors and values of their redox potentials. The latter effect was shown to be independent of the ArcAB regulatory system.

Curvature bound from gravitational catalysis

Science.gov (United States)

Gies, Holger; Martini, Riccardo

2018-04-01

We determine bounds on the curvature of local patches of spacetime from the requirement of intact long-range chiral symmetry. The bounds arise from a scale-dependent analysis of gravitational catalysis and its influence on the effective potential for the chiral order parameter, as induced by fermionic fluctuations on a curved spacetime with local hyperbolic properties. The bound is expressed in terms of the local curvature scalar measured in units of a gauge-invariant coarse-graining scale. We argue that any effective field theory of quantum gravity obeying this curvature bound is safe from chiral symmetry breaking through gravitational catalysis and thus compatible with the simultaneous existence of chiral fermions in the low-energy spectrum. With increasing number of dimensions, the curvature bound in terms of the hyperbolic scale parameter becomes stronger. Applying the curvature bound to the asymptotic safety scenario for quantum gravity in four spacetime dimensions translates into bounds on the matter content of particle physics models.

Quinone reduction via secondary B-branch electron transfer in mutant bacterial reaction centers.

Science.gov (United States)

Laible, Philip D; Kirmaier, Christine; Udawatte, Chandani S M; Hofman, Samuel J; Holten, Dewey; Hanson, Deborah K

2003-02-18

Symmetry-related branches of electron-transfer cofactors-initiating with a primary electron donor (P) and terminating in quinone acceptors (Q)-are common features of photosynthetic reaction centers (RC). Experimental observations show activity of only one of them-the A branch-in wild-type bacterial RCs. In a mutant RC, we now demonstrate that electron transfer can occur along the entire, normally inactive B-branch pathway to reduce the terminal acceptor Q(B) on the time scale of nanoseconds. The transmembrane charge-separated state P(+)Q(B)(-) is created in this manner in a Rhodobacter capsulatus RC containing the F(L181)Y-Y(M208)F-L(M212)H-W(M250)V mutations (YFHV). The W(M250)V mutation quantitatively blocks binding of Q(A), thereby eliminating Q(B) reduction via the normal A-branch pathway. Full occupancy of the Q(B) site by the native UQ(10) is ensured (without the necessity of reconstitution by exogenous quinone) by purification of RCs with the mild detergent, Deriphat 160-C. The lifetime of P(+)Q(B)(-) in the YFHV mutant RC is >6 s (at pH 8.0, 298 K). This charge-separated state is not formed upon addition of competitive inhibitors of Q(B) binding (terbutryn or stigmatellin). Furthermore, this lifetime is much longer than the value of approximately 1-1.5 s found when P(+)Q(B)(-) is produced in the wild-type RC by A-side activity alone. Collectively, these results demonstrate that P(+)Q(B)(-) is formed solely by activity of the B-branch carriers in the YFHV RC. In comparison, P(+)Q(B)(-) can form by either the A or B branches in the YFH RC, as indicated by the biexponential lifetimes of approximately 1 and approximately 6-10 s. These findings suggest that P(+)Q(B)(-) states formed via the two branches are distinct and that P(+)Q(B)(-) formed by the B side does not decay via the normal (indirect) pathway that utilizes the A-side cofactors when present. These differences may report on structural and energetic factors that further distinguish the functional

Deeply bound pionic atom

International Nuclear Information System (INIS)

Toki, Hiroshi; Yamazaki, Toshimitsu

1989-01-01

The standard method of pionic atom formation does not produce deeply bound pionic atoms. A study is made on the properties of deeply bound pionic atom states by using the standard pion-nucleus optical potential. Another study is made to estimate the cross sections of the formation of ls pionic atom states by various methods. The pion-nucleus optical potential is determined by weakly bound pionic atom states and pion nucleus scattering. Although this potential may not be valid for deeply bound pionic atoms, it should provide some hint on binding energies and level widths of deeply bound states. The width of the ls state comes out to be 0.3 MeV and is well separated from the rest. The charge dependence of the ls state is investigated. The binding energies and the widths increase linearly with Z azbove a Z of 30. The report then discusses various methods to populate deeply bound pionic atoms. In particular, 'pion exchange' reactions are proposed. (n, pπ) reaction is discussed first. The cross section is calculated by assuming the in- and out-going nucleons on-shell and the produced pion in (n1) pionic atom states. Then, (n, dπ - ) cross sections are estimated. (p, 2 Heπ - ) reaction would have cross sections similar to the cross section of (n, dπ - ) reaction. In conclusion, it seems best to do (n, p) experiment on heavy nuclei for deeply bound pionic atom. (Nogami, K.)

Journal of Biosciences | Indian Academy of Sciences

Indian Academy of Sciences (India)

Keywords. Antioxidant; biofertilizer and biocontrol agent; biosensor; pharmacological agent; protein kinase inducer; pyrroloquinoline-quinone. Abstract. Pyrroloquinoline-quinine (PQQ) was initially characterized as a redox cofactor for membrane-bound dehydrogenases in the bacterial system. Subsequently, PQQ was ...

Bounding species distribution models

Directory of Open Access Journals (Sweden)

Thomas J. STOHLGREN, Catherine S. JARNEVICH, Wayne E. ESAIAS,Jeffrey T. MORISETTE

2011-10-01

Full Text Available Species distribution models are increasing in popularity for mapping suitable habitat for species of management concern. Many investigators now recognize that extrapolations of these models with geographic information systems (GIS might be sensitive to the environmental bounds of the data used in their development, yet there is no recommended best practice for “clamping” model extrapolations. We relied on two commonly used modeling approaches: classification and regression tree (CART and maximum entropy (Maxent models, and we tested a simple alteration of the model extrapolations, bounding extrapolations to the maximum and minimum values of primary environmental predictors, to provide a more realistic map of suitable habitat of hybridized Africanized honey bees in the southwestern United States. Findings suggest that multiple models of bounding, and the most conservative bounding of species distribution models, like those presented here, should probably replace the unbounded or loosely bounded techniques currently used [Current Zoology 57 (5: 642–647, 2011].

Bounding Species Distribution Models

Science.gov (United States)

Stohlgren, Thomas J.; Jarnevich, Cahterine S.; Morisette, Jeffrey T.; Esaias, Wayne E.

2011-01-01

Species distribution models are increasing in popularity for mapping suitable habitat for species of management concern. Many investigators now recognize that extrapolations of these models with geographic information systems (GIS) might be sensitive to the environmental bounds of the data used in their development, yet there is no recommended best practice for "clamping" model extrapolations. We relied on two commonly used modeling approaches: classification and regression tree (CART) and maximum entropy (Maxent) models, and we tested a simple alteration of the model extrapolations, bounding extrapolations to the maximum and minimum values of primary environmental predictors, to provide a more realistic map of suitable habitat of hybridized Africanized honey bees in the southwestern United States. Findings suggest that multiple models of bounding, and the most conservative bounding of species distribution models, like those presented here, should probably replace the unbounded or loosely bounded techniques currently used [Current Zoology 57 (5): 642-647, 2011].

Labeling schemes for bounded degree graphs

DEFF Research Database (Denmark)

Adjiashvili, David; Rotbart, Noy Galil

2014-01-01

We investigate adjacency labeling schemes for graphs of bounded degree Δ = O(1). In particular, we present an optimal (up to an additive constant) log n + O(1) adjacency labeling scheme for bounded degree trees. The latter scheme is derived from a labeling scheme for bounded degree outerplanar...... graphs. Our results complement a similar bound recently obtained for bounded depth trees [Fraigniaud and Korman, SODA 2010], and may provide new insights for closing the long standing gap for adjacency in trees [Alstrup and Rauhe, FOCS 2002]. We also provide improved labeling schemes for bounded degree...

Hydroquinone and Quinone-Grafted Porous Carbons for Highly Selective CO2 Capture from Flue Gases and Natural Gas Upgrading.

Science.gov (United States)

Wang, Jun; Krishna, Rajamani; Yang, Jiangfeng; Deng, Shuguang

2015-08-04

Hydroquinone and quinone functional groups were grafted onto a hierarchical porous carbon framework via the Friedel-Crafts reaction to develop more efficient adsorbents for the selective capture and removal of carbon dioxide from flue gases and natural gas. The oxygen-doped porous carbons were characterized with scanning electron microscopy, transmission electron microscopy, X-ray powder diffraction, Fourier transform infrared spectroscopy, and Raman spectroscopy. CO2, CH4, and N2 adsorption isotherms were measured and correlated with the Langmuir model. An ideal adsorbed solution theory (IAST) selectivity for the CO2/N2 separation of 26.5 (298 K, 1 atm) was obtained on the hydroquinone-grafted carbon, which is 58.7% higher than that of the pristine porous carbon, and a CO2/CH4 selectivity value of 4.6 (298 K, 1 atm) was obtained on the quinone-grafted carbon (OAC-2), which represents a 28.4% improvement over the pristine porous carbon. The highest CO2 adsorption capacity on the oxygen-doped carbon adsorbents is 3.46 mmol g(-1) at 298 K and 1 atm. In addition, transient breakthrough simulations for CO2/CH4/N2 mixture separation were conducted to demonstrate the good separation performance of the oxygen-doped carbons in fixed bed adsorbers. Combining excellent adsorption separation properties and low heats of adsorption, the oxygen-doped carbons developed in this work appear to be very promising for flue gas treatment and natural gas upgrading.

Requirement of histidine 217 for ubiquinone reductase activity (Qi site) in the cytochrome bc1 complex.

Science.gov (United States)

Gray, K A; Dutton, P L; Daldal, F

1994-01-25

Folding models suggest that the highly conserved histidine 217 of the cytochrome b subunit from the cytochrome bc1 complex is close to the quinone reductase (Qi) site. This histidine (bH217) in the cytochrome b polypeptide of the photosynthetic bacterium Rhodobacter capsulatus has been replaced with three other residues, aspartate (D), arginine (R), and leucine (L). bH217D and bH217R are able to grow photoheterotrophically and contain active cytochrome bc1 complexes (60% of wild-type activity), whereas the bH217L mutant is photosynthetically incompetent and contains a cytochrome bc1 complex that has only 10% of the wild-type activity. Single-turnover flash-activated electron transfer experiments show that cytochrome bH is reduced via the Qo site with near native rates in the mutant strains but that electron transfer between cytochrome bH and quinone bound at the Qi site is greatly slowed. These results are consistent with redox midpoint potential (Em) measurements of the cytochrome b subunit hemes and the Qi site quinone. The Em values of cyt bL and bH are approximately the same in the mutants and wild type, although the mutant strains have a larger relative concentration of what may be the high-potential form of cytochrome bH, called cytochrome b150. However, the redox properties of the semiquinone at the Qi site are altered significantly. The Qi site semiquinone stability constant of bH217R is 10 times higher than in the wild type, while in the other two strains (bH217D and bH217L) the stability constant is much lower than in the wild type. Thus H217 appears to have major effects on the redox properties of the quinone bound at the Qi site. These data are incorporated into a suggestion that H217 forms part of the binding pocket of the Qi site in a manner reminiscent of the interaction between quinone bound at the Qb site and H190 of the L subunit of the bacterial photosynthetic reaction center.

Scattering by bound nucleons

International Nuclear Information System (INIS)

Tezuka, Hirokazu.

1984-10-01

Scattering of a particle by bound nucleons is discussed. Effects of nucleons that are bound in a nucleus are taken as a structure function. The way how to calculate the structure function is given. (author)

Structural and functional investigation of flavin binding center of the NqrC subunit of sodium-translocating NADH:quinone oxidoreductase from Vibrio harveyi.

Directory of Open Access Journals (Sweden)

Valentin Borshchevskiy

Full Text Available Na+-translocating NADH:quinone oxidoreductase (NQR is a redox-driven sodium pump operating in the respiratory chain of various bacteria, including pathogenic species. The enzyme has a unique set of redox active prosthetic groups, which includes two covalently bound flavin mononucleotide (FMN residues attached to threonine residues in subunits NqrB and NqrC. The reason of FMN covalent bonding in the subunits has not been established yet. In the current work, binding of free FMN to the apo-form of NqrC from Vibrio harveyi was studied showing very low affinity of NqrC to FMN in the absence of its covalent bonding. To study structural aspects of flavin binding in NqrC, its holo-form was crystallized and its 3D structure was solved at 1.56 Å resolution. It was found that the isoalloxazine moiety of the FMN residue is buried in a hydrophobic cavity and that its pyrimidine ring is squeezed between hydrophobic amino acid residues while its benzene ring is extended from the protein surroundings. This structure of the flavin-binding pocket appears to provide flexibility of the benzene ring, which can help the FMN residue to take the bended conformation and thus to stabilize the one-electron reduced form of the prosthetic group. These properties may also lead to relatively weak noncovalent binding of the flavin. This fact along with periplasmic location of the FMN-binding domains in the vast majority of NqrC-like proteins may explain the necessity of the covalent bonding of this prosthetic group to prevent its loss to the external medium.

Characterization of PEDOT-Quinone Conducting Redox Polymers for Water Based Secondary Batteries

International Nuclear Information System (INIS)

Sterby, Mia; Emanuelsson, Rikard; Huang, Xiao; Gogoll, Adolf; Strømme, Maria; Sjödin, Martin

2017-01-01

Lithium-ion technologies show great promise to meet the demands that the transition towards renewable energy sources and the electrification of the transport sector put forward. However, concerns regarding lithium-ion batteries, including limited material resources, high energy consumption during production, and flammable electrolytes, necessitate research on alternative technologies for electrochemical energy storage. Organic materials derived from abundant building blocks and with tunable properties, together with water based electrolytes, could provide safe, inexpensive and sustainable alternatives. In this study, two conducting redox polymers based on poly(3,4-ethylenedioxythiophene) (PEDOT) and a hydroquinone pendant group have been synthesized and characterized in an acidic aqueous electrolyte. The polymers were characterized with regards to kinetics, pH dependence, and mass changes during oxidation and reduction, as well as their conductance. Both polymers show redox matching, i.e. the quinone redox reaction occurs within the potential region where the polymer is conducting, and fast redox conversion that involves proton cycling during pendant group redox conversion. These properties make the presented materials promising candidates as electrode materials for water based all-organic batteries.

Bounds for Asian basket options

Science.gov (United States)

Deelstra, Griselda; Diallo, Ibrahima; Vanmaele, Michèle

2008-09-01

In this paper we propose pricing bounds for European-style discrete arithmetic Asian basket options in a Black and Scholes framework. We start from methods used for basket options and Asian options. First, we use the general approach for deriving upper and lower bounds for stop-loss premia of sums of non-independent random variables as in Kaas et al. [Upper and lower bounds for sums of random variables, Insurance Math. Econom. 27 (2000) 151-168] or Dhaene et al. [The concept of comonotonicity in actuarial science and finance: theory, Insurance Math. Econom. 31(1) (2002) 3-33]. We generalize the methods in Deelstra et al. [Pricing of arithmetic basket options by conditioning, Insurance Math. Econom. 34 (2004) 55-57] and Vanmaele et al. [Bounds for the price of discrete sampled arithmetic Asian options, J. Comput. Appl. Math. 185(1) (2006) 51-90]. Afterwards we show how to derive an analytical closed-form expression for a lower bound in the non-comonotonic case. Finally, we derive upper bounds for Asian basket options by applying techniques as in Thompson [Fast narrow bounds on the value of Asian options, Working Paper, University of Cambridge, 1999] and Lord [Partially exact and bounded approximations for arithmetic Asian options, J. Comput. Finance 10 (2) (2006) 1-52]. Numerical results are included and on the basis of our numerical tests, we explain which method we recommend depending on moneyness and time-to-maturity.

Expression of NAD(P)H quinone dehydrogenase 1 (NQO1) is increased in the endometrium of women with endometrial cancer and women with polycystic ovary syndrome

DEFF Research Database (Denmark)

Atiomo, William; Shafiee, Mohamad Nasir; Chapman, Caroline

2017-01-01

of differentially expressed genes identified by RNA sequencing, including NAD(P)H quinone dehydrogenase 1 (NQO1), was validated by quantitative reverse transcriptase PCR validation (n = 76) and in the cancer genome atlas UCEC (uterine corpus endometrioid carcinoma) RNA sequencing data set (n = 381). The expression...

Market access through bound tariffs

DEFF Research Database (Denmark)

Sala, Davide; Yalcin, Erdal; Schröder, Philipp

2010-01-01

on the risk that exporters face in destination markets. The present paper formalizes the underlying interaction of risk, fixed export costs and firms' market entry decisions based on techniques known from the real options literature; doing so we highlight the important role of bound tariffs at the extensive...... margin of trade. We find that bound tariffs are more effective with higher risk destination markets, that a large binding overhang may still command substantial market access, and that reductions in bound tariffs generate effective market access even when bound rates are above current and longterm...

Market Access through Bound Tariffs

DEFF Research Database (Denmark)

Sala, Davide; Schröder, Philipp J.H.; Yalcin, Erdal

on the risk that exporters face in destination markets. The present paper formalizes the underlying interaction of risk, fixed export costs and firms' market entry decisions based on techniques known from the real options literature; doing so we highlight the important role of bound tariffs at the extensive...... margin of trade. We find that bound tariffs are more effective with higher risk destination markets, that a large binding overhang may still command substantial market access, and that reductions in bound tariffs generate effective market access even when bound rates are above current and long...

Bound and rebound states

International Nuclear Information System (INIS)

Orzalesi, C.A.

1979-01-01

In relativistic quantum theory, bound states generate forces in the crossed channel; such forces can affect the binding and self-consistent solutions should be sought for the bound-state problem. The author investigates how self-consistency can be achieved by successive approximations, in a simple scalar model and with successive relativistic eikonal approximations (EAs). Within the generalized ladder approximation, some exact properties of the resulting ''first generation'' bound states are discussed. The binding energies in this approximation are rather small even for rather large values of the primary coupling constant. The coupling of the constituent particles to the first-generation reggeon is determined by a suitable EA and a new generalized ladder amplitude is constructed with rungs given either by the primary gluons or by the first-generation reggeons. The resulting new (second-generation) bound states are found in a reggeized EA. The size of the corrections to the binding energies due to the rebinding effects is surprisingly large. The procedure is then iterated, so as to find - again in an EA - the third-generation bound states. The procedure is found to be self-consistent already at this stage: the third-generation bound states coincide with those of second generation, and no further rebinding takes place in the higher iterations of the approximation method. Features - good and bad - of the model are discussed, as well as the possible relevance of rebinding mechanisms in hadron dynamics. (author)

Enhanced PM10 bounded PAHs from shipping emissions

Science.gov (United States)

Pongpiachan, S.; Hattayanone, M.; Choochuay, C.; Mekmok, R.; Wuttijak, N.; Ketratanakul, A.

2015-05-01

Earlier studies have highlighted the importance of maritime transport as a main contributor of air pollutants in port area. The authors intended to investigate the effects of shipping emissions on the enhancement of PM10 bounded polycyclic aromatic hydrocarbons (PAHs) and mutagenic substances in an industrial area of Rayong province, Thailand. Daily PM10 speciation data across two air quality observatory sites in Thailand during 2010-2013 were collected. Diagnostic binary ratios of PAH congeners, analysis of variances (ANOVA), and principal component analysis (PCA) were employed to evaluate the enhanced genotoxicity of PM10 during the docking period. Significant increase of PAHs and mutagenic index (MI) of PM10 were observed during the docking period in both sampling sites. Although stationary sources like coal combustions from power plants and vehicular exhausts from motorway can play a great role in enhancing PAH concentrations, regulating shipping emissions from diesel engine in the port area like Rayong is predominantly crucial.

Oxadiazole-substituted naphtho[2,3-b]thiophene-4,9-diones as potent inhibitors of keratinocyte hyperproliferation. Structure-activity relationships of the tricyclic quinone skeleton and the oxadiazole substituent

DEFF Research Database (Denmark)

Basoglu, Atila; Dirkmann, Simone; Zahedi Golpayegani, Nader

2017-01-01

Novel analogues of oxadiazole-substituted naphtho[2,3-b]thiophene-4,9-diones were synthesized in which the tricyclic quinone skeleton was systematically replaced with simpler moieties, such as structures with fewer rings and open-chain forms, while the oxadiazole ring was maintained. In addition...

Electron transfer pathways in microbial oxygen biocathodes

Energy Technology Data Exchange (ETDEWEB)

Freguia, Stefano, E-mail: stefano@kais.kyoto-u.ac.j [Bio-analytical and Physical Chemistry Laboratory, Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8205 (Japan); Tsujimura, Seiya, E-mail: seiya@kais.kyoto-u.ac.j [Bio-analytical and Physical Chemistry Laboratory, Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8205 (Japan); Kano, Kenji, E-mail: kkano@kais.kyoto-u.ac.j [Bio-analytical and Physical Chemistry Laboratory, Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8205 (Japan)

2010-01-01

The ability of some bacteria to enhance the rate of cathodic oxygen reduction to water has been recently discovered, opening the way to an entirely renewable and environmentally friendly concept of biocathode. In this study we reveal that several mechanisms may induce catalytic effects by bacteria. These comprise mechanisms that are putatively beneficial to the bacteria as well as mechanisms which are merely side effects, including quinone autoxidation and direct O{sub 2} reduction by heme compounds. Here we showed that 1 muM of ACNQ is able to generate a significant catalytic wave for oxygen reduction, with onset at approximately 0 V vs. SHE. Similarly, adsorption of hemin on a carbon surface catalyses O{sub 2} reduction to H{sub 2}O{sub 2} with an onset of +0.2 V vs. SHE. To evaluate the catalytic pathways of live cells on cathodic oxygen reduction, two species of electrochemically active bacteria were selected as pure cultures, namely Acinetobacter calcoaceticus and Shewanella putrefaciens. The former appears to exploit a self-excreted redox compound with redox characteristics matching those of pyrroloquinoline quinone (PQQ) for extracellular electron transfer. The latter appears to utilise outer membrane-bound redox compounds. Interaction of quinones and cytochromes with the membrane-bound electron transfer chain is yet to be proven.

Metabolism of organically bound tritium

International Nuclear Information System (INIS)

Travis, C.C.

1984-01-01

The classic methodology for estimating dose to man from environmental tritium ignores the fact that organically bound tritium in foodstuffs may be directly assimilated in the bound compartment of tissues without previous oxidation. We propose a four-compartment model consisting of a free body water compartment, two organic compartments, and a small, rapidly metabolizing compartment. The utility of this model lies in the ability to input organically bound tritium in foodstuffs directly into the organic compartments of the model. We found that organically bound tritium in foodstuffs can increase cumulative total body dose by a factor of 1.7 to 4.5 times the free body water dose alone, depending on the bound-to-loose ratio of tritium in the diet. Model predictions are compared with empirical measurements of tritium in human urine and tissue samples, and appear to be in close agreement. 10 references, 4 figures, 3 tables

Bound states in string nets

Science.gov (United States)

Schulz, Marc Daniel; Dusuel, Sébastien; Vidal, Julien

2016-11-01

We discuss the emergence of bound states in the low-energy spectrum of the string-net Hamiltonian in the presence of a string tension. In the ladder geometry, we show that a single bound state arises either for a finite tension or in the zero-tension limit depending on the theory considered. In the latter case, we perturbatively compute the binding energy as a function of the total quantum dimension. We also address this issue in the honeycomb lattice where the number of bound states in the topological phase depends on the total quantum dimension. Finally, the internal structure of these bound states is analyzed in the zero-tension limit.

Bounding approaches to system identification

CERN Document Server

Norton, John; Piet-Lahanier, Hélène; Walter, Éric

1996-01-01

In response to the growing interest in bounding error approaches, the editors of this volume offer the first collection of papers to describe advances in techniques and applications of bounding of the parameters, or state variables, of uncertain dynamical systems. Contributors explore the application of the bounding approach as an alternative to the probabilistic analysis of such systems, relating its importance to robust control-system design.

Einstein and the "Crucial" Experiment

Science.gov (United States)

Holton, Gerald

1969-01-01

Examines the widespread view that it was the crucial Michelson-Morley experiment that led Einstein to formulate the special relativity theory. From Einstein's writings, evidence is presented that no such direct genetic connection exists. The author suggests that the historian of science must resist the experimenticist's fallacy of imposing a…

Bounded Intention Planning Revisited

OpenAIRE

Sievers Silvan; Wehrle Martin; Helmert Malte

2014-01-01

Bounded intention planning provides a pruning technique for optimal planning that has been proposed several years ago. In addition partial order reduction techniques based on stubborn sets have recently been investigated for this purpose. In this paper we revisit bounded intention planning in the view of stubborn sets.

Bounded Gaussian process regression

DEFF Research Database (Denmark)

Jensen, Bjørn Sand; Nielsen, Jens Brehm; Larsen, Jan

2013-01-01

We extend the Gaussian process (GP) framework for bounded regression by introducing two bounded likelihood functions that model the noise on the dependent variable explicitly. This is fundamentally different from the implicit noise assumption in the previously suggested warped GP framework. We...... with the proposed explicit noise-model extension....

A symmetric Roos bound for linear codes

NARCIS (Netherlands)

Duursma, I.M.; Pellikaan, G.R.

2006-01-01

The van Lint–Wilson AB-method yields a short proof of the Roos bound for the minimum distance of a cyclic code. We use the AB-method to obtain a different bound for the weights of a linear code. In contrast to the Roos bound, the role of the codes A and B in our bound is symmetric. We use the bound

Bounded Tamper Resilience

DEFF Research Database (Denmark)

Damgård, Ivan Bjerre; Faust, Sebastian; Mukherjee, Pratyay

2013-01-01

Related key attacks (RKAs) are powerful cryptanalytic attacks where an adversary can change the secret key and observe the effect of such changes at the output. The state of the art in RKA security protects against an a-priori unbounded number of certain algebraic induced key relations, e.......g., affine functions or polynomials of bounded degree. In this work, we show that it is possible to go beyond the algebraic barrier and achieve security against arbitrary key relations, by restricting the number of tampering queries the adversary is allowed to ask for. The latter restriction is necessary......-protocols (including the Okamoto scheme, for instance) are secure even if the adversary can arbitrarily tamper with the prover’s state a bounded number of times and obtain some bounded amount of leakage. Interestingly, for the Okamoto scheme we can allow also independent tampering with the public parameters. We show...

P2-16: Dual-Bound Model and the Role of Time Bound in Perceptual Decision Making

Directory of Open Access Journals (Sweden)

Daeseob Lim

2012-10-01

Full Text Available The diffusion model (DM encapsulates the dynamics of perceptual decision within a ‘diffusion field’ that is defined by a basis with sensory-evidence (SE and time vectors. At the core of the DM, it assumes that a decision is not made until an evidence particle drifts in the diffusion field and eventually hits one of the two pre-fixed bounds defined in the SE axis. This assumption dictates when and which choice is made by referring to when and which bound will be hit by the evidence particle. What if urgency pressures the decision system to make a choice even when the evidence particle has yet hit the SE bound? Previous modeling attempts at coping with time pressure, despite differences in detail, all manipulated the coordinate of SE bounds. Here, we offer a novel solution by adopting another bound on the time axis. This ‘dual-bound’ model (DBM posits that decisions can also be made when the evidence particle hits a time bound, which is determined on a trial-by-trial basis by a ‘perceived time interval’ – how long the system can stay in the ‘diffusion’ field. The classic single-bound model (SBM exhibited systematic errors in predicting both the reaction time distributions and the time-varying bias in choice. Those errors were not corrected by previously proposed variants of the SBM until the time bound was introduced. The validity of the DBM was further supported by the strong across-individual correlation between observed precision of interval timing and the predicted trial-by-trial variability of the time bound.

Syntrophic Growth via Quinone-Mediated Interspecies Electron Transfer

Directory of Open Access Journals (Sweden)

Jessica A Smith

2015-02-01

Full Text Available The mechanisms by which microbial species exchange electrons are of interest because interspecies electron transfer can expand the metabolic capabilities of microbial communities. Previous studies with the humic substance analog anthraquinone-2,6-disulfonate (AQDS suggested that quinone-mediated interspecies electron transfer (QUIET is feasible, but it was not determined if sufficient energy is available from QUIET to support the growth of both species. Furthermore, there have been no previous studies on the mechanisms for the oxidation of anthrahydroquinone-2,6-disulfonate (AHQDS. A co-culture of Geobacter metallireducens and Geobacter sulfurreducens metabolized ethanol with the reduction of fumarate much faster in the presence of AQDS, and there was an increase in cell protein. G. sulfurreducens was more abundant, consistent with G. sulfurreducens obtaining electrons from acetate that G. metallireducens produced from ethanol, as well as from AHQDS. Cocultures initiated with a citrate synthase-deficient strain of G. sulfurreducens that was unable to use acetate as an electron donor also metabolized ethanol with the reduction of fumarate and cell growth, but acetate accumulated over time. G. sulfurreducens and G. metallireducens were equally abundant in these co-cultures reflecting the inability of the citrate synthase-deficient strain of G. sulfurreducens to metabolize acetate. Evaluation of the mechanisms by which G. sulfurreducens accepts electrons from AHQDS demonstrated that a strain deficient in outer-surface c-type cytochromes that are required for AQDS reduction was as effective at QUIET as the wild-type strain. Deletion of additional genes previously implicated in extracellular electron transfer also had no impact on QUIET. These results demonstrate that QUIET can yield sufficient energy to support the growth of both syntrophic partners, but that the mechanisms by which electrons are derived from extracellular hydroquinones require

Bioorthogonal Metabolic DNA Labelling using Vinyl Thioether-Modified Thymidine and o-Quinolinone Quinone Methide.

Science.gov (United States)

Gubu, Amu; Li, Long; Ning, Yan; Zhang, Xiaoyun; Lee, Seonghyun; Feng, Mengke; Li, Qiang; Lei, Xiaoguang; Jo, Kyubong; Tang, Xinjing

2018-04-17

Bioorthogonal metabolic DNA labeling with fluorochromes is a powerful strategy to visualize DNA molecules and their functions. Here, we report the development of a new DNA metabolic labeling strategy enabled by the catalyst-free bioorthogonal ligation using vinyl thioether modified thymidine and o-quinolinone quinone methide. With the newly designed vinyl thioether-modified thymidine (VTdT), we added labeling tags on cellular DNA, which could further be linked to fluorochromes in cells. Therefore, we successfully visualized the DNA localization within cells as well as single DNA molecules without other staining reagents. In addition, we further characterized this bioorthogonal DNA metabolic labeling using DNase I digestion, MS characterization of VTdT as well as VTdT-oQQF conjugate in cell nuclei or mitochondria. This technique provides a powerful strategy to study DNA in cells, which paves the way to achieve future spatiotemporal deciphering of DNA synthesis and functions. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Inducible Alkylation of DNA by a Quinone Methide-Peptide Nucleic Acid Conjugate†

Science.gov (United States)

Liu, Yang; Rokita, Steven E.

2012-01-01

The reversibility of alkylation by a quinone methide intermediate (QM) avoids the irreversible consumption that plagues most reagents based on covalent chemistry and allows for site specific reaction that is controlled by the thermodynamics rather than kinetics of target association. This characteristic was originally examined with an oligonucleotide QM conjugate but broad application depends on alternative derivatives that are compatible with a cellular environment. Now, a peptide nucleic acid (PNA) derivative has been constructed and shown to exhibit an equivalent ability to delivery the reactive QM in a controlled manner. This new conjugate demonstrates high selectivity for a complementary sequence of DNA even when challenged with an alternative sequence containing a single T/T mismatch. Alkylation of non-complementary sequences is only possible when a template strand is present to co-localize the conjugate and its target. For efficient alkylation in this example, a single-stranded region of the target is required adjacent to the QM conjugate. Most importantly, the intrastrand self adducts formed between the PNA and its attached QM remained active and reversible over more than eight days in aqueous solution prior to reaction with a chosen target added subsequently. PMID:22243337

Carbon nanotube-supported Au-Pd alloy with cooperative effect of metal nanoparticles and organic ketone/quinone groups as a highly efficient catalyst for aerobic oxidation of amines.

Science.gov (United States)

Deng, Weiping; Chen, Jiashu; Kang, Jincan; Zhang, Qinghong; Wang, Ye

2016-05-21

Functionalised carbon nanotube (CNT)-supported Au-Pd alloy nanoparticles were highly efficient catalysts for the aerobic oxidation of amines. We achieved the highest turnover frequencies (>1000 h(-1)) for the oxidative homocoupling of benzylamine and the oxidative dehydrogenation of dibenzylamine. We discovered a cooperative effect between Au-Pd nanoparticles and ketone/quinone groups on CNTs.

Instanton bound states in ABJM theory

Energy Technology Data Exchange (ETDEWEB)

Hatsuda, Yasuyuki [DESY Hamburg (Germany). Theory Group; Tokyo Institute of Technology (Japan). Dept. of Physics; Moriyama, Sanefumi [Nagoya Univ. (Japan). Kobayashi Maskawa Inst. and Graduate School of Mathematics; Okuyama, Kazumi [Shinshu Univ., Matsumoto, Nagano (Japan). Dept. of Physics

2013-06-15

The partition function of the ABJM theory receives non-perturbative corrections due to instanton effects. We study these non-perturbative corrections, including bound states of worldsheet instantons and membrane instantons, in the Fermi-gas approach. We require that the total non-perturbative correction should be always finite for arbitrary Chern-Simons level. This finiteness is realized quite non-trivially because each bound state contribution naively diverges at some levels. The poles of each contribution should be canceled out in total. We use this pole cancellation mechanism to find unknown bound state corrections from known ones. We conjecture a general expression of the bound state contribution. Summing up all the bound state contributions, we find that the effect of bound states is simply incorporated into the worldsheet instanton correction by a redefinition of the chemical potential in the Fermi-gas system. Analytic expressions of the 3- and 4-membrane instanton corrections are also proposed.

Career Development and Personal Functioning Differences between Work-Bound and Non-Work Bound Students

Science.gov (United States)

Creed, Peter A.; Patton, Wendy; Hood, Michelle

2010-01-01

We surveyed 506 Australian high school students on career development (exploration, planning, job-knowledge, decision-making, indecision), personal functioning (well-being, self-esteem, life satisfaction, school satisfaction) and control variables (parent education, school achievement), and tested differences among work-bound, college-bound and…

Formation of Molecular Networks: Tailored Quantum Boxes and Behavior of Adsorbed CO in Them

Science.gov (United States)

Wyrick, Jon; Sun, Dezheng; Kim, Dae-Ho; Cheng, Zhihai; Lu, Wenhao; Zhu, Yeming; Luo, Miaomiao; Kim, Yong Su; Rotenberg, Eli; Kim, Kwangmoo; Einstein, T. L.; Bartels, Ludwig

2011-03-01

We show that the behavior of CO adsorbed into the pores of large regular networks on Cu(111) is significantly affected by their nano-scale lateral confinement and that formation of the networks themselves is directed by the Shockley surface state. Saturation coverages of CO are found to exhibit persistent dislocation lines; at lower coverages their mobility increases. Individual CO within the pores titrate the surface state, providing crucial information for understanding formation of the network as a result of optimization of the number N of electrons bound within each pore. Determination of N is based on quinone-coverage-dependent UPS data and an analysis of states of particles in a pore-shaped box (verified by CO's titration); a wide range of possible pore shapes and sizes has been considered. Work at UCR supported by NSF CHE 07-49949; at UMD by NSF CHE 07-50334 & UMD NSF-MRSEC DMR 05-20471.

Crucial test of the Dirac cosmologies

International Nuclear Information System (INIS)

Steigman, G.

1978-01-01

In a cosmology consistent with the Cosmological Principle (large scale, statistical isotropy and homogeneity of the universe), a Planck spectrum is not preserved as the universe evolves unless the number of photons in a comoving volume is conserved. It is shown that a large class of cosmological models based on Dirac's Large Numbers Hypothesis (LNH) violate this constraint. The observed isotropy and spectral distribution of the microwave background radiation thus provide a crucial test of such cosmologies. After reviewing the LNH, the general evolution of radiation spectra in cosmologies consistent with the cosmological principle is outlined. It is shown that the predicted deviations from a Planck spectrum for Dirac cosmologies (as well as for ''tired-light'' cosmologies) are enormous. The Planckian (or near-Planckian) spectral form for the microwave radiation provides a crucial test, failed by such cosmologies

Determining Normal-Distribution Tolerance Bounds Graphically

Science.gov (United States)

Mezzacappa, M. A.

1983-01-01

Graphical method requires calculations and table lookup. Distribution established from only three points: mean upper and lower confidence bounds and lower confidence bound of standard deviation. Method requires only few calculations with simple equations. Graphical procedure establishes best-fit line for measured data and bounds for selected confidence level and any distribution percentile.

Binding energies of two deltas bound states

International Nuclear Information System (INIS)

Sato, Hiroshi; Saito, Koichi.

1982-06-01

Bound states of the two-deltas system are investigated by employing the realistic one boson exchange potential. It is found that there exist many bound states in each isospin channel and also found that the tensor interaction plays important role in producing these bound states. Relationship between these bound states and dibaryon resonances is discussed. (J.P.N.)

Variational lower bound on the scattering length

International Nuclear Information System (INIS)

Rosenberg, L.; Spruch, L.

1975-01-01

The scattering length A characterizes the zero-energy scattering of one system by another. It was shown some time ago that a variational upper bound on A could be obtained using methods, of the Rayleigh-Ritz type, which are commonly employed to obtain upper bounds on energy eigenvalues. Here we formulate a method for obtaining a variational lower bound on A. Once again the essential idea is to express the scattering length as a variational estimate plus an error term and then to reduce the problem of bounding the error term to one involving bounds on energy eigenvalues. In particular, the variational lower bound on A is rigorously established provided a certin modified Hamiltonian can be shown to have no discrete states lying below the level of the continuum threshold. It is unfortunately true that necessary conditions for the existence of bound states are not available for multiparticle systems in general. However, in the case of positron-atom scattering the adiabatic approximation can be introduced as an (essentially) solvable comparison problem to rigorously establish the nonexistence of bound states of the modified Hamiltonian. It has recently been shown how the validity of the variational upper bound on A can be maintained when the target ground-state wave function is imprecisely known. Similar methods can be used to maintain the variational lower bound on A. Since the bound is variational, the error in the calculated scattering length will be of second order in the error in the wave function. The use of the adiabatic approximation in the present context places no limitation in principle on the accuracy achievable

Aluminum stimulates uptake of non-transferrin bound iron and transferrin bound iron in human glial cells

International Nuclear Information System (INIS)

Kim, Yongbae; Olivi, Luisa; Cheong, Jae Hoon; Maertens, Alex; Bressler, Joseph P.

2007-01-01

Aluminum and other trivalent metals were shown to stimulate uptake of transferrin bound iron and nontransferrin bound iron in erytholeukemia and hepatoma cells. Because of the association between aluminum and Alzheimer's Disease, and findings of higher levels of iron in Alzheimer's disease brains, the effects of aluminum on iron homeostasis were examined in a human glial cell line. Aluminum stimulated dose- and time-dependent uptake of nontransferrin bound iron and iron bound to transferrin. A transporter was likely involved in the uptake of nontransferrin iron because uptake reached saturation, was temperature-dependent, and attenuated by inhibitors of protein synthesis. Interestingly, the effects of aluminum were not blocked by inhibitors of RNA synthesis. Aluminum also decreased the amount of iron bound to ferritin though it did not affect levels of divalent metal transporter 1. These results suggest that aluminum disrupts iron homeostasis in Brain by several mechanisms including the transferrin receptor, a nontransferrin iron transporter, and ferritin

Carbon Inputs From Riparian Vegetation Limit Oxidation of Physically Bound Organic Carbon Via Biochemical and Thermodynamic Processes

Science.gov (United States)

Graham, Emily B.; Tfaily, Malak M.; Crump, Alex R.; Goldman, Amy E.; Bramer, Lisa M.; Arntzen, Evan; Romero, Elvira; Resch, C. Tom; Kennedy, David W.; Stegen, James C.

2017-12-01

In light of increasing terrestrial carbon (C) transport across aquatic boundaries, the mechanisms governing organic carbon (OC) oxidation along terrestrial-aquatic interfaces are crucial to future climate predictions. Here we investigate the biochemistry, metabolic pathways, and thermodynamics corresponding to OC oxidation in the Columbia River corridor using ultrahigh-resolution C characterization. We leverage natural vegetative differences to encompass variation in terrestrial C inputs. Our results suggest that decreases in terrestrial C deposition associated with diminished riparian vegetation induce oxidation of physically bound OC. We also find that contrasting metabolic pathways oxidize OC in the presence and absence of vegetation and—in direct conflict with the "priming" concept—that inputs of water-soluble and thermodynamically favorable terrestrial OC protect bound-OC from oxidation. In both environments, the most thermodynamically favorable compounds appear to be preferentially oxidized regardless of which OC pool microbiomes metabolize. In turn, we suggest that the extent of riparian vegetation causes sediment microbiomes to locally adapt to oxidize a particular pool of OC but that common thermodynamic principles govern the oxidation of each pool (i.e., water-soluble or physically bound). Finally, we propose a mechanistic conceptualization of OC oxidation along terrestrial-aquatic interfaces that can be used to model heterogeneous patterns of OC loss under changing land cover distributions.

Capacity Bounds for Parallel Optical Wireless Channels

KAUST Repository

Chaaban, Anas; Rezki, Zouheir; Alouini, Mohamed-Slim

2016-01-01

A system consisting of parallel optical wireless channels with a total average intensity constraint is studied. Capacity upper and lower bounds for this system are derived. Under perfect channel-state information at the transmitter (CSIT), the bounds have to be optimized with respect to the power allocation over the parallel channels. The optimization of the lower bound is non-convex, however, the KKT conditions can be used to find a list of possible solutions one of which is optimal. The optimal solution can then be found by an exhaustive search algorithm, which is computationally expensive. To overcome this, we propose low-complexity power allocation algorithms which are nearly optimal. The optimized capacity lower bound nearly coincides with the capacity at high SNR. Without CSIT, our capacity bounds lead to upper and lower bounds on the outage probability. The outage probability bounds meet at high SNR. The system with average and peak intensity constraints is also discussed.

Product differentiation under bounded rationality

NARCIS (Netherlands)

Vermeulen, B.; Poutré, La J.A.; Kok, de A.G.; Pyka, A.; Handa, H.; Ishibuchi, H.; Ong, Y.-S.; Tan, K.-C.

2015-01-01

We study product differentiation equilibria and dynamics on the Salop circle under bounded rationality. Due to bounded rationality, firms tend to agglomerate in pairs. Upon adding a second tier of component suppliers, downstream assemblers may escape pairwise horizontal agglomeration. Moreover, we

Massive Galileon positivity bounds

Science.gov (United States)

de Rham, Claudia; Melville, Scott; Tolley, Andrew J.; Zhou, Shuang-Yong

2017-09-01

The EFT coefficients in any gapped, scalar, Lorentz invariant field theory must satisfy positivity requirements if there is to exist a local, analytic Wilsonian UV completion. We apply these bounds to the tree level scattering amplitudes for a massive Galileon. The addition of a mass term, which does not spoil the non-renormalization theorem of the Galileon and preserves the Galileon symmetry at loop level, is necessary to satisfy the lowest order positivity bound. We further show that a careful choice of successively higher derivative corrections are necessary to satisfy the higher order positivity bounds. There is then no obstruction to a local UV completion from considerations of tree level 2-to-2 scattering alone. To demonstrate this we give an explicit example of such a UV completion.

New bounds on isotropic Lorentz violation

International Nuclear Information System (INIS)

Carone, Christopher D.; Sher, Marc; Vanderhaeghen, Marc

2006-01-01

Violations of Lorentz invariance that appear via operators of dimension four or less are completely parametrized in the Standard Model Extension (SME). In the pure photonic sector of the SME, there are 19 dimensionless, Lorentz-violating parameters. Eighteen of these have experimental upper bounds ranging between 10 -11 and 10 -32 ; the remaining parameter, k-tilde tr , is isotropic and has a much weaker bound of order 10 -4 . In this Brief Report, we point out that k-tilde tr gives a significant contribution to the anomalous magnetic moment of the electron and find a new upper bound of order 10 -8 . With reasonable assumptions, we further show that this bound may be improved to 10 -14 by considering the renormalization of other Lorentz-violating parameters that are more tightly constrained. Using similar renormalization arguments, we also estimate bounds on Lorentz-violating parameters in the pure gluonic sector of QCD

Tight Bounds for Distributed Functional Monitoring

DEFF Research Database (Denmark)

Woodruff, David P.; Zhang, Qin

2011-01-01

$, our bound resolves their main open question. Our lower bounds are based on new direct sum theorems for approximate majority, and yield significant improvements to problems in the data stream model, improving the bound for estimating $F_p, p > 2,$ in $t$ passes from $\\tilde{\\Omega}(n^{1-2/p}/(\\eps^{2/p......} t))$ to $\\tilde{\\Omega}(n^{1-2/p}/(\\eps^{4/p} t))$, giving the first bound for estimating $F_0$ in $t$ passes of $\\Omega(1/(\\eps^2 t))$ bits of space that does not use the gap-hamming problem, and showing a distribution for the gap-hamming problem with high external information cost or super...

Spectroscopic and molecular docking studies on the charge transfer complex of bovine serum albumin with quinone in aqueous medium and its influence on the ligand binding property of the protein

Science.gov (United States)

Satheshkumar, Angupillai; Elango, Kuppanagounder P.

2014-09-01

The spectral techniques such as UV-Vis, 1H NMR and fluorescence and electrochemical experiments have been employed to investigate the interaction between 2-methoxy-3,5,6-trichloro-1,4-benzoquinone (MQ; a water soluble quinone) and bovine serum albumin (BSA) in aqueous medium. The fluorescence of BSA was quenched by MQ via formation of a 1:1 BSA-MQ charge transfer adduct with a formation constant of 3.3 × 108 L mol-1. Based on the Forster’s theory the binding distance between them is calculated as 2.65 nm indicating high probability of binding. For the first time, influence of quinone on the binding property of various types of ligands such as aspirin, ascorbic acid, nicotinimide and sodium stearate has also been investigated. The results indicated that the strong and spontaneous binding existing between BSA and MQ, decreased the intensity of binding of these ligands with BSA. Since Tryptophan (Trp) is the basic residue present in BSA, a comparison between binding property of Trp-MQ adduct with that of BSA-MQ with these ligands has also been attempted. 1H NMR titration study indicated that the Trp forms a charge transfer complex with MQ, which reduces the interaction of Trp with the ligands. Molecular docking study supported the fact that the quinone interacts with the Trp212 unit of the BSA and the free energy change of binding (ΔG) for the BSA-MQ complex was found to be -46 kJ mol-1, which is comparable to our experimental free energy of binding (-49 kJ mol-1) obtained from fluorescence study.

Combining Alphas via Bounded Regression

Directory of Open Access Journals (Sweden)

Zura Kakushadze

2015-11-01

Full Text Available We give an explicit algorithm and source code for combining alpha streams via bounded regression. In practical applications, typically, there is insufficient history to compute a sample covariance matrix (SCM for a large number of alphas. To compute alpha allocation weights, one then resorts to (weighted regression over SCM principal components. Regression often produces alpha weights with insufficient diversification and/or skewed distribution against, e.g., turnover. This can be rectified by imposing bounds on alpha weights within the regression procedure. Bounded regression can also be applied to stock and other asset portfolio construction. We discuss illustrative examples.

Quasi-bound states in continuum

International Nuclear Information System (INIS)

Nakamura, Hiroaki; Hatano, Naomichi; Garmon, Sterling; Petrosky, Tomio

2007-08-01

We report the prediction of quasi-bound states (resonant states with very long lifetimes) that occur in the eigenvalue continuum of propagating states for a wide region of parameter space. These quasi-bound states are generated in a quantum wire with two channels and an adatom, when the energy bands of the two channels overlap. A would-be bound state that lays just below the upper energy band is slightly destabilized by the lower energy band and thereby becomes a resonant state with a very long lifetime (a second QBIC lays above the lower energy band). (author)

Bisphenol A 3,4-quinone induces the conversion of xanthine dehydrogenase into oxidase in vitro.

Science.gov (United States)

Sakuma, Satoru; Nakanishi, Masahiko; Morinaga, Kazuhiro; Fujitake, Mihoyo; Wada, Shun-ichi; Fujimoto, Yohko

2010-01-01

In the present study, we assessed the influence of bisphenol A (BPA) and bisphenol A 3,4-quinone (BPAQ) on the conversion of xanthine dehydrogenase (XD) into xanthine oxidase (XO) in the rat liver in vitro. BPA up to 100 micromol/L did not affect the XO and XD activities in the partially purified cytosolic fraction from rat liver, whereas BPAQ (2-10 micromol/L) dose-dependently enhanced the XO activity concomitant with a decrease in the XD activity, implying that BPAQ, but not BPA, can convert XD into the reactive oxygen species (ROS) producing the form XO. Furthermore, it was found that BPAQ could increase the generation of ROS and oxidize the guanine moiety of deoxyguanosine in the DNA of primary rat hepatocyte cultures. These results suggest that BPAQ has the potential to convert XD into XO in the liver, which in turn may lead to ROS generation and oxidative DNA damage in this region. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

Pyrroloquinoline quinone ameliorates l-thyroxine-induced hyperthyroidism and associated problems in rats.

Science.gov (United States)

Kumar, Narendra; Kar, Anand; Panda, Sunanda

2014-08-01

Pyrroloquinoline quinone (PQQ) is believed to be a strong antioxidant. In this study, we have evaluated its hitherto unknown role in l-thyroxin (L-T4 )-induced hyperthyroidism considering laboratory rat as a model. Alterations in the serum concentration of thyroxin (T4 ) and triiodothyronine (T3 ); lipid peroxidation (LPO) of liver, kidney, heart, muscles and brain; in the endogenous antioxidants such as superoxide dismutase, catalase and glutathione and in serum total cholesterol, high-density lipoprotien, triglycerides, serum glutamate pyruvate transaminase (SGPT), serum glutamate oxaloacetate transaminase (SGOT) and urea were evaluated. Administration of l-T4 (500-µg kg(-1) body weight) enhanced not only the serum T3 and T4 levels but also the tissue LPO, serum SGOT, SGPT and urea with a parallel decrease in the levels of antioxidants and serum lipids. However, on simultaneous administration of PQQ (5 mg kg(-1) for 6 days), all these adverse effects were ameliorated, indicating the potential of PQQ in the amelioration of hyperthyroidism and associated problems. Possibly, the curative effects were mediated through inhibition of oxidative stress. We suggest that PQQ may be considered for therapeutic use for hyperthyroidism after dose standardization. Copyright © 2014 John Wiley & Sons, Ltd.

Cranberry extract-enriched diets increase NAD(P)H:quinone oxidoreductase and catalase activities in obese but not in nonobese mice.

Science.gov (United States)

Boušová, Iva; Bártíková, Hana; Matoušková, Petra; Lněničková, Kateřina; Zappe, Lukáš; Valentová, Kateřina; Szotáková, Barbora; Martin, Jan; Skálová, Lenka

2015-10-01

Consumption of antioxidant-enriched diets is 1 method of addressing obesity, which is associated with chronic oxidative stress and changes in the activity/expression of various enzymes. In this study, we hypothesized that the modulation of antioxidant enzymes and redox status through a cranberry extract (CBE)-enriched diet would differ between obese and nonobese mice. The CBE used in this study was obtained from the American cranberry (Vaccinium macrocarpon, Ericaceae), a popular constituent of dietary supplements that is a particularly rich source of (poly)phenols and has strong antioxidant properties. The present study was designed to test and compare the in vivo effects of 28-day consumption of a CBE-enriched diet (2%) on the antioxidant status of nonobese mice and mice with monosodium glutamate-induced obesity. Plasma, erythrocytes, liver, and small intestine were studied concurrently to obtain more complex information. The specific activities, protein, and messenger RNA expression levels of antioxidant enzymes as well as the levels of malondialdehyde and thiol (SH) groups were analyzed. Cranberry extract treatment increased the SH group content in plasma and the glutathione S-transferase activity in the erythrocytes of the obese and nonobese mice. In addition, in the obese animals, the CBE treatment reduced the malondialdehyde content in erythrocytes and increased quinone oxidoreductase (liver) and catalase (erythrocytes and small intestine) activities. The elevation of hepatic quinone oxidoreductase activity was accompanied by an increase in the corresponding messenger RNA levels. The effects of CBE on the activity of antioxidant enzymes and redox status were more pronounced in the obese mice compared with the nonobese mice. Copyright © 2015 Elsevier Inc. All rights reserved.

Bounded Rationality and Budgeting

OpenAIRE

Ibrahim, Mukdad

2016-01-01

This article discusses the theory of bounded rationality which had been introduced by Herbert Simon in the 1950s. Simon introduced the notion of bounded rationality stating that while decision-makers strive for rationality, they are limited by the effect of the environment, their information process capacity and by the constraints on their information storage and retrieval capabilities. Moreover, this article tries to specifically blend this notion into budgeting, using the foundations of inc...

A quick response fluorescent probe based on coumarin and quinone for glutathione and its application in living cells

Energy Technology Data Exchange (ETDEWEB)

Dai, Xi [Institute of Organic Chemistry, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China); Du, Zhi-Fang [Taishan College, Shandong University, Jinan 250100 (China); Wang, Li-Hong; Miao, Jun-Ying [Institute of Developmental Biology, School of Life Science, Shandong University, Jinan 250100 (China); Zhao, Bao-Xiang, E-mail: bxzhao@sdu.edu.cn [Institute of Organic Chemistry, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China)

2016-05-30

We have designed and synthesized a simple but effective fluorescent probe for sensing glutathione (GSH) by PET process based on coumarin and quinone, which worked as fluorophore and reaction site, respectively. The probe could discriminate GSH from cysteine and homocysteine within 1 min in PBS-buffered solution. The sensing mechanism was confirmed by density functional theory (DFT), viscosity test, fluorescence spectrum analysis and HRMS, respectively. The probe has a low limit of detection (0.1 μM) and finally been used in cell imaging successfully. - Highlights: • This probe can discriminate glutathione from sulfhydryl compound by PET process. • This probe can be used to determine glutathione in aqueous solution within 1 min. • This probe has been successfully applied in living cell image.

A quick response fluorescent probe based on coumarin and quinone for glutathione and its application in living cells

International Nuclear Information System (INIS)

Dai, Xi; Du, Zhi-Fang; Wang, Li-Hong; Miao, Jun-Ying; Zhao, Bao-Xiang

2016-01-01

We have designed and synthesized a simple but effective fluorescent probe for sensing glutathione (GSH) by PET process based on coumarin and quinone, which worked as fluorophore and reaction site, respectively. The probe could discriminate GSH from cysteine and homocysteine within 1 min in PBS-buffered solution. The sensing mechanism was confirmed by density functional theory (DFT), viscosity test, fluorescence spectrum analysis and HRMS, respectively. The probe has a low limit of detection (0.1 μM) and finally been used in cell imaging successfully. - Highlights: • This probe can discriminate glutathione from sulfhydryl compound by PET process. • This probe can be used to determine glutathione in aqueous solution within 1 min. • This probe has been successfully applied in living cell image.

Fuzzy upper bounds and their applications

Energy Technology Data Exchange (ETDEWEB)

Soleimani-damaneh, M. [Department of Mathematics, Faculty of Mathematical Science and Computer Engineering, Teacher Training University, 599 Taleghani Avenue, Tehran 15618 (Iran, Islamic Republic of)], E-mail: soleimani_d@yahoo.com

2008-04-15

This paper considers the concept of fuzzy upper bounds and provides some relevant applications. Considering a fuzzy DEA model, the existence of a fuzzy upper bound for the objective function of the model is shown and an effective approach to solve that model is introduced. Some dual interpretations are provided, which are useful for practical purposes. Applications of the concept of fuzzy upper bounds in two physical problems are pointed out.

A Lagrangian lower bound for the container transshipment problem at a railway hub for a fast branch-and-bound algorithm

OpenAIRE

M Barketau; H Kopfer; E Pesch

2013-01-01

In this paper, we consider the container transshipment problem at a railway hub. A simple lower bound known for this problem will be improved by a new Lagrangian relaxation lower bound. Computational tests show that this lower bound outperforms the simple one and decreases substantially the run time of the branch-and-bound algorithm.

In vivo induction of phase II detoxifying enzymes, glutathione transferase and quinone reductase by citrus triterpenoids

Directory of Open Access Journals (Sweden)

Ahmad Hassan

2010-09-01

Full Text Available Abstract Background Several cell culture and animal studies demonstrated that citrus bioactive compounds have protective effects against certain types of cancer. Among several classes of citrus bioactive compounds, limonoids were reported to prevent different types of cancer. Furthermore, the structures of citrus limonoids were reported to influence the activity of phase II detoxifying enzymes. The purpose of the study was to evaluate how variations in the structures of citrus limonoids (namely nomilin, deacetyl nomilin, and isoobacunoic acid and a mixture of limonoids would influence phase II enzyme activity in excised tissues from a mouse model. Methods In the current study, defatted sour orange seed powder was extracted with ethyl acetate and subjected to silica gel chromatography. The HPLC, NMR and mass spectra were used to elucidate the purity and structure of compounds. Female A/J mice were treated with three limonoids and a mixture in order to evaluate their effect on phase II enzymes in four different tissues. Assays for glutathione S-transferase and NAD(PH: quinone reductase (QR were used to evaluate induction of phase II enzymatic activity. Results The highest induction of GST against 1-chloro-2,4-dinitrobenzene (CDNB was observed in stomach (whole, 58% by nomilin, followed by 25% isoobacunoic acid and 19% deacetyl nomilin. Deacetyl nomilin in intestine (small as well as liver significantly reduced GST activity against CDNB. Additionally isoobacunoic acid and the limonoid mixture in liver demonstrated a significant reduction of GST activity against CDNB. Nomilin significantly induced GST activity against 4-nitroquinoline 1-oxide (4NQO, intestine (280% and stomach (75% while deacetyl nomilin showed significant induction only in intestine (73%. Induction of GST activity was also observed in intestine (93% and stomach (45% treated with the limonoid mixture. Finally, a significant induction of NAD(PH: quinone reductase (QR activity was

Improved Range Searching Lower Bounds

DEFF Research Database (Denmark)

Larsen, Kasper Green; Nguyen, Huy L.

2012-01-01

by constructing a hard input set and query set, and then invoking Chazelle and Rosenberg's [CGTA'96] general theorem on the complexity of navigation in the pointer machine. For the group model, we show that input sets and query sets that are hard for range reporting in the pointer machine (i.e. by Chazelle...... and Rosenberg's theorem), are also hard for dynamic range searching in the group model. This theorem allows us to reuse decades of research on range reporting lower bounds to immediately obtain a range of new group model lower bounds. Amongst others, this includes an improved lower bound for the fundamental...

Two-phonon bound states in imperfect crystals

International Nuclear Information System (INIS)

Behera, S.N.; Samsur, Sk.

1980-01-01

The question of the occurrence of two-phonon bound states in imperfect crystals is investigated. It is shown that the anharmonicity mediated two-phonon bound state which is present in perfect crystals gets modified due to the presence of impurities. Moreover, the possibility of the occurrence of a purely impurity mediated two-phonon bound state is demonstrated. The bound state frequencies are calculated using the simple Einstein oscillator model for the host phonons. The two-phonon density of states for the imperfect crystal thus obtained has peaks at the combination and difference frequencies of two host phonons besides the peaks at the bound state frequencies. For a perfect crystal the theory predicts a single peak at the two-phonon bound state frequency in conformity with experimental observations and other theoretical calculations. Experimental data on the two-phonon infrared absorption and Raman scattering from mixed crystals of Gasub(1-c)Alsub(c)P and Gesub(1-c)Sisub(c) are analysed to provide evidence in support of impurity-mediated two-phonon bound states. The relevance of the zero frequency (difference spectrum) peak to the central peak, observed in structural phase transitions, is conjectured. (author)

On semidefinite programming bounds for graph bandwidth

NARCIS (Netherlands)

de Klerk, E.; Nagy, M.; Sotirov, R.

2013-01-01

In this paper, we propose two new lower bounds on graph bandwidth and cyclic bandwidth based on semidefinite programming (SDP) relaxations of the quadratic assignment problem. We compare the new bounds with two other SDP bounds reported in [A. Blum, G. Konjevod, R. Ravi, and S. Vempala,

Bounded elements in Locally C*-algebras

International Nuclear Information System (INIS)

El Harti, Rachid

2001-09-01

In order to get more useful information about Locally C*-algebras, we introduce in this paper the notion of bounded elements. First, we study the connection between bounded elements and spectrally bounded elements. Some structural results of Locally C*-algebras are established in Theorems 1 , 2 and 3. As an immediate consequence of Theorem 3, we give a characterization of the connected component of the identity in the group of unitary elements for a Locally C*-algebra. (author)

Covariant entropy bound and loop quantum cosmology

International Nuclear Information System (INIS)

Ashtekar, Abhay; Wilson-Ewing, Edward

2008-01-01

We examine Bousso's covariant entropy bound conjecture in the context of radiation filled, spatially flat, Friedmann-Robertson-Walker models. The bound is violated near the big bang. However, the hope has been that quantum gravity effects would intervene and protect it. Loop quantum cosmology provides a near ideal setting for investigating this issue. For, on the one hand, quantum geometry effects resolve the singularity and, on the other hand, the wave function is sharply peaked at a quantum corrected but smooth geometry, which can supply the structure needed to test the bound. We find that the bound is respected. We suggest that the bound need not be an essential ingredient for a quantum gravity theory but may emerge from it under suitable circumstances.

Degenerate quantum codes and the quantum Hamming bound

International Nuclear Information System (INIS)

Sarvepalli, Pradeep; Klappenecker, Andreas

2010-01-01

The parameters of a nondegenerate quantum code must obey the Hamming bound. An important open problem in quantum coding theory is whether the parameters of a degenerate quantum code can violate this bound for nondegenerate quantum codes. In this article we show that Calderbank-Shor-Steane (CSS) codes, over a prime power alphabet q≥5, cannot beat the quantum Hamming bound. We prove a quantum version of the Griesmer bound for the CSS codes, which allows us to strengthen the Rains' bound that an [[n,k,d

Some Improved Nonperturbative Bounds for Fermionic Expansions

Energy Technology Data Exchange (ETDEWEB)

Lohmann, Martin, E-mail: marlohmann@gmail.com [Universita di Roma Tre, Dipartimento di Matematica (Italy)

2016-06-15

We reconsider the Gram-Hadamard bound as it is used in constructive quantum field theory and many body physics to prove convergence of Fermionic perturbative expansions. Our approach uses a recursion for the amplitudes of the expansion, discovered in a model problem by Djokic (2013). It explains the standard way to bound the expansion from a new point of view, and for some of the amplitudes provides new bounds, which avoid the use of Fourier transform, and are therefore superior to the standard bounds for models like the cold interacting Fermi gas.

Bounded Rationality in the Developmental Trajectory of Environmental Target Policy in China, 1972–2016

Directory of Open Access Journals (Sweden)

Rui Mu

2018-01-01

Full Text Available This article applies the theoretical notion of “bounded rationality” to understand and to explain the updates of the Environmental Target Policy (ETP in China during 1972–2016. An analytical framework is built up by combining the phase model and the stream model in policy science in order to trace the longitudinal transformation of the ETP. In addition, the article adopts the “event sequence method” to discover the dynamics of the problem, politics, and policy streams of the target policy and to identify the evolving coupling between the different streams. It shows that China’s ETP has experienced five phases of development. For each phase the central government had its specific bounded rationality to make the crucial decision on the ETP. The decisions on the ETP in different phases were made when policy windows were open with the coupling of the problem, politics, and policy streams. As for the updates of the ETP, we find that the rationalities of the central governments in the five phases were limited by the emergent practices during the ETP implementation, which gave momentum to the central government to seek new solutions and to revise and adapt the ETP.

Sharp Bounds for Symmetric and Asymmetric Diophantine Approximation

Institute of Scientific and Technical Information of China (English)

Cornelis KRAAIKAMP; Ionica SMEETS

2011-01-01

In 2004,Tong found bounds for the approximation quality of a regular continued fraction convergent to a rational number,expressed in bounds for both the previous and next approximation.The authors sharpen his results with a geometric method and give both sharp upper and lower bounds.The asymptotic frequencies that these bounds occur are also calculated.

SHARP ENTRYWISE PERTURBATION BOUNDS FOR MARKOV CHAINS.

Science.gov (United States)

Thiede, Erik; VAN Koten, Brian; Weare, Jonathan

For many Markov chains of practical interest, the invariant distribution is extremely sensitive to perturbations of some entries of the transition matrix, but insensitive to others; we give an example of such a chain, motivated by a problem in computational statistical physics. We have derived perturbation bounds on the relative error of the invariant distribution that reveal these variations in sensitivity. Our bounds are sharp, we do not impose any structural assumptions on the transition matrix or on the perturbation, and computing the bounds has the same complexity as computing the invariant distribution or computing other bounds in the literature. Moreover, our bounds have a simple interpretation in terms of hitting times, which can be used to draw intuitive but rigorous conclusions about the sensitivity of a chain to various types of perturbations.

21 CFR 862.1640 - Protein-bound iodine test system.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Protein-bound iodine test system. 862.1640 Section... Systems § 862.1640 Protein-bound iodine test system. (a) Identification. A protein-bound iodine test system is a device intended to measure protein-bound iodine in serum. Measurements of protein-bound...

Relativistic bound state wave functions

International Nuclear Information System (INIS)

Micu, L.

2005-01-01

A particular method of writing the bound state wave functions in relativistic form is applied to the solutions of the Dirac equation with confining potentials in order to obtain a relativistic description of a quark antiquark bound system representing a given meson. Concerning the role of the effective constituent in the present approach we first observe that without this additional constituent we couldn't expand the bound state wave function in terms of products of free states. Indeed, we notice that if the wave function depends on the relative coordinates only, all the expansion coefficients would be infinite. Secondly we remark that the effective constituent enabled us to give a Lorentz covariant meaning to the potential energy of the bound system which is now seen as the 4th component of a 4-momentum. On the other side, by relating the effective constituent to the quantum fluctuations of the background field which generate the binding, we provided a justification for the existence of some spatial degrees of freedom accompanying the interaction potential. These ones, which are quite unusual in quantum mechanics, in our model are the natural consequence of the the independence of the quarks and can be seen as the effect of the imperfect cancellation of the vector momenta during the quantum fluctuations. Related with all these we remark that the adequate representation for the relativistic description of a bound system is the momentum representation, because of the transparent and easy way of writing the conservation laws and the transformation properties of the wave functions. The only condition to be fulfilled is to find a suitable way to take into account the potential energy of the bound system. A particular feature of the present approach is that the confining forces are due to a kind of glue where both quarks are embedded. This recalls other bound state models where the wave function is factorized in terms of constituent wave functions and the confinement is

Bounds on poloidal kinetic energy in plane layer convection

Science.gov (United States)

Tilgner, A.

2017-12-01

A numerical method is presented that conveniently computes upper bounds on heat transport and poloidal energy in plane layer convection for infinite and finite Prandtl numbers. The bounds obtained for the heat transport coincide with earlier results. These bounds imply upper bounds for the poloidal energy, which follow directly from the definitions of dissipation and energy. The same constraints used for computing upper bounds on the heat transport lead to improved bounds for the poloidal energy.

Persistence-Based Branch Misprediction Bounds for WCET Analysis

DEFF Research Database (Denmark)

Puffitsch, Wolfgang

2015-01-01

Branch prediction is an important feature of pipelined processors to achieve high performance. However, it can lead to overly pessimistic worst-case execution time (WCET) bounds when being modeled too conservatively. This paper presents bounds on the number of branch mispredictions for local...... dynamic branch predictors. To handle interferences between branch instructions we use the notion of persistence, a concept that is also found in cache analyses. The bounds apply to branches in general, not only to branches that close a loop. Furthermore, the bounds can be easily integrated into integer...... linear programming formulations of the WCET problem. An evaluation on a number of benchmarks shows that with these bounds, dynamic branch prediction does not necessarily lead to higher WCET bounds than static prediction schemes....

Positivity bounds on double parton distributions

International Nuclear Information System (INIS)

Diehl, Markus; Kasemets, Tomas

2013-03-01

Double hard scattering in proton-proton collisions is described in terms of double parton distributions. We derive bounds on these distributions that follow from their interpretation as probability densities, taking into account all possible spin correlations between two partons in an unpolarized proton. These bounds constrain the size of the polarized distributions and can for instance be used to set upper limits on the effects of spin correlations in double hard scattering. We show that the bounds are stable under leading-order DGLAP evolution to higher scales.

Comparison of Lasserre's Measure-based Bounds for Polynomial Optimization to Bounds Obtained by Simulated Annealing

NARCIS (Netherlands)

de Klerk, Etienne; Laurent, Monique

We consider the problem of minimizing a continuous function f over a compact set K. We compare the hierarchy of upper bounds proposed by Lasserre in [SIAM J. Optim. 21(3) (2011), pp. 864-885] to bounds that may be obtained from simulated annealing. We show that, when f is a polynomial and K a convex

Universal bounds in even-spin CFTs

Energy Technology Data Exchange (ETDEWEB)

Qualls, Joshua D. [Department of Physics, National Taiwan University,Taipei, Taiwan (China)

2015-12-01

We prove using invariance under the modular S− and ST−transformations that every unitary two-dimensional conformal field theory (CFT) having only even-spin primary operators (with no extended chiral algebra and with right- and left-central charges c,c̃>1) contains a primary operator with dimension Δ{sub 1} satisfying 0<Δ{sub 1}<((c+c̃)/24)+0.09280…. After deriving both analytical and numerical bounds, we discuss how to extend our methods to bound higher conformal dimensions before deriving lower and upper bounds on the number of primary operators in a given energy range. Using the AdS{sub 3}/CFT{sub 2} dictionary, the bound on Δ{sub 1} proves the lightest massive excitation in appropriate theories of 3D matter and gravity with cosmological constant Λ<0 can be no heavier than 1/8G{sub N}+O(√(−Λ)); the bounds on the number of operators are related via AdS/CFT to the entropy of states in the dual gravitational theory. In the flat-space approximation, the limiting mass is exactly that of the lightest BTZ black hole.

Formation of quinones by one-electron oxidation in the metabolism of benzo[a]pyrene and 6-fluorobenzo[a]pyrene

International Nuclear Information System (INIS)

Cavalieri, E.; Wong, A.; Cremonesi, P.; Warner, C.; Rogan, E.

1986-01-01

Metabolic activation of polycyclic aromatic hydrocarbons (PAH), as well as other chemical carcinogens, occurs by two major pathways: One-electron oxidation and two-electron oxidation, or monooxygenation. One-electron oxidation generates radical cations or radicals, depending on the molecule in which the oxidation occurs, whereas two-electron oxidation produces oxygenated metabolites. Radical cations of PAH are ultimate electrophilic metabolites capable of binding to cellular macromolecules to initiate the tumor process. In this paper the authors will provide evidence that one-electron oxidation is involved not only in PAH carcinogenesis, but also in the formation of certain metabolites. Metabolism of benzo[a]pyrene (BP) by cytochrome P-450 monooxygenase yields three classes of products: phenols, dihydrodiols and the quinones, 1,6-, 3,6- and 6,12- dione

A cannabigerol quinone alleviates neuroinflammation in a chronic model of multiple sclerosis.

Science.gov (United States)

Granja, Aitor G; Carrillo-Salinas, Francisco; Pagani, Alberto; Gómez-Cañas, María; Negri, Roberto; Navarrete, Carmen; Mecha, Miriam; Mestre, Leyre; Fiebich, Bend L; Cantarero, Irene; Calzado, Marco A; Bellido, Maria L; Fernandez-Ruiz, Javier; Appendino, Giovanni; Guaza, Carmen; Muñoz, Eduardo

2012-12-01

Phytocannabinoids like ∆(9)-tetrahydrocannabinol (THC) and cannabidiol (CBD) show a beneficial effect on neuroinflammatory and neurodegenerative processes through cell membrane cannabinoid receptor (CBr)-dependent and -independent mechanisms. Natural and synthetic cannabinoids also target the nuclear receptor peroxisome proliferator-activated receptor-gamma (PPARγ), an attractive molecular target for the treatment of neuroinflammation. As part of a study on the SAR of phytocannabinoids, we have investigated the effect of the oxidation modification in the resorcinol moiety of cannabigerol (CBG) on CB(1), CB(2) and PPARγ binding affinities, identifying cannabigerol quinone (VCE-003) as a potent anti-inflammatory agent. VCE-003 protected neuronal cells from excitotoxicity, activated PPARγ transcriptional activity and inhibited the release of pro-inflammatory mediators in LPS-stimulated microglial cells. Theiler's murine encephalomyelitis virus (TMEV) model of multiple sclerosis (MS) was used to investigate the anti-inflammatory activity of this compound in vivo. Motor function performance was evaluated and the neuroinflammatory response and gene expression pattern in brain and spinal cord were studied by immunostaining and qRT-PCR. We found that VCE-003 ameliorated the symptoms associated to TMEV infection, decreased microglia reactivity and modulated the expression of genes involved in MS pathophysiology. These data lead us to consider VCE-003 to have high potential for drug development against MS and perhaps other neuroinflammatory diseases.

Comparison of the Biological Properties of Several Marine Sponge-Derived Sesquiterpenoid Quinones

Directory of Open Access Journals (Sweden)

Ping Yin

2007-07-01

Full Text Available Eight naturally occurring marine-sponge derived sesquiterpenoid quinones wereevaluated as potential inhibitors of pyruvate phosphate dikinase (PPDK, a C4 plantregulatory enzyme. Of these, the hydroxyquinones ilimaquinone, ethylsmenoquinone andsmenoquinone inhibited PPDK activity with IC50’s (reported with 95% confidenceintervals of 285.4 (256.4 – 317.7, 316.2 (279.2 – 358.1 and 556.0 (505.9 – 611.0 μM,respectively, as well as being phytotoxic to the C4 plant Digitaria ciliaris. The potentialanti-inflammatory activity of these compounds, using bee venom phospholipase A2(PLA2, was also evaluated. Ethylsmenoquinone, smenospongiarine, smenospongidine andilimaquinone inhibited PLA2 activity (% inhibition of 73.2 + 4.8 at 269 μM, 61.5 + 6.1 at242 μM, 41.0 + 0.6 at 224 μM and 36.4 + 8.2 at 279 μM, respectively. SAR analysesindicate that a hydroxyquinone functionality and a short, hydroxide/alkoxide side-chain atC-20 is preferred for inhibition of PPDK activity, and that a larger amine side-chain at C-20 is tolerated for PLA2 inhibitory activity.

The paediatric Bohler's angle and crucial angle of Gissane: a case series

Directory of Open Access Journals (Sweden)

Crawford Haemish A

2011-01-01

Full Text Available Abstract Background Bohler's angle and the crucial angle of Gissane can be used to assess calcaneal fractures. While the normal adult values of these angles are widely known, the normal paediatric values have not yet been established. Our aim is to investigate Bohler's angle and the crucial angle of Gissane in a paediatric population and establish normal paediatric reference values. Method We measured Bohler's angle and the crucial angle of Gissane using normal plain ankle radiographs of 763 patients from birth to 14 years of age completed over a five year period from July 2003 to June 2008. Results In our paediatric study group, the mean Bohler's angle was 35.2 degrees and the mean crucial angle of Gissane was 111.3 degrees. In an adult comparison group, the mean Bohler's angle was 39.2 degrees and the mean crucial angle of Gissane was 113.8 degrees. The differences in Bohler's angle and the crucial angle of Gissane between these two groups were statistically significant. Conclusion We have presented the normal values of Bohler's angle and the crucial angle of Gissane in a paediatric population. These values may provide a useful comparison to assist with the management of the paediatric calcaneal fracture.

Lower bounds for the minimum distance of algebraic geometry codes

DEFF Research Database (Denmark)

Beelen, Peter

, such as the Goppa bound, the Feng-Rao bound and the Kirfel-Pellikaan bound. I will finish my talk by giving several examples. Especially for two-point codes, the generalized order bound is fairly easy to compute. As an illustration, I will indicate how a lower bound can be obtained for the minimum distance of some...... description of these codes in terms of order domains has been found. In my talk I will indicate how one can use the ideas behind the order bound to obtain a lower bound for the minimum distance of any AG-code. After this I will compare this generalized order bound with other known lower bounds...

Absolute Lower Bound on the Bounce Action

Science.gov (United States)

Sato, Ryosuke; Takimoto, Masahiro

2018-03-01

The decay rate of a false vacuum is determined by the minimal action solution of the tunneling field: bounce. In this Letter, we focus on models with scalar fields which have a canonical kinetic term in N (>2 ) dimensional Euclidean space, and derive an absolute lower bound on the bounce action. In the case of four-dimensional space, we show the bounce action is generically larger than 24 /λcr, where λcr≡max [-4 V (ϕ )/|ϕ |4] with the false vacuum being at ϕ =0 and V (0 )=0 . We derive this bound on the bounce action without solving the equation of motion explicitly. Our bound is derived by a quite simple discussion, and it provides useful information even if it is difficult to obtain the explicit form of the bounce solution. Our bound offers a sufficient condition for the stability of a false vacuum, and it is useful as a quick check on the vacuum stability for given models. Our bound can be applied to a broad class of scalar potential with any number of scalar fields. We also discuss a necessary condition for the bounce action taking a value close to this lower bound.

Evacuation of Bed-bound Patients-STEPS Simulations

DEFF Research Database (Denmark)

Madsen, Anne; Dederichs, Anne Simone

2016-01-01

Fires in hospitals occur, and evacuation of bed-bound patients might be necessary in case of emergency. The current study concerns the evacuation of bed-bound patients from a fire section in a hospital using hospital porters. The simulations are performed using the STEPS program. The aim...... of the study is to investigate the evacuation time of bed-bound hospital patients using different walking speeds from the literature, and the influence of the number of hospital porters on the total evacuation times of bed-bound patients. Different scenarios were carried out with varying staff......-to-patient ratios that simulate the horizontal evacuation of 40 bed-bound patients into a different fire section. It was found that the staff-to-patient-ratio affects the total evacuation times. However, the total evacuation times do not decrease linearly and a saturation effect is seen at a staff-to-patient ratio...

Bounds in the location-allocation problem

DEFF Research Database (Denmark)

Juel, Henrik

1981-01-01

Develops a family of stronger lower bounds on the objective function value of the location-allocation problem. Solution methods proposed to solve problems in location-allocation; Efforts to develop a more efficient bound solution procedure; Determination of the locations of the sources....

No-arbitrage bounds for financial scenarios

DEFF Research Database (Denmark)

Geyer, Alois; Hanke, Michael; Weissensteiner, Alex

2014-01-01

We derive no-arbitrage bounds for expected excess returns to generate scenarios used in financial applications. The bounds allow to distinguish three regions: one where arbitrage opportunities will never exist, a second where arbitrage may be present, and a third, where arbitrage opportunities...

Antiplasmodial, cytotoxic activities and characterization of a new naturally occurring quinone methide pentacyclic triterpenoid derivative isolated from Salacia leptoclada Tul. (Celastraceae) originated from Madagascar.

Science.gov (United States)

Ruphin, Fatiany Pierre; Baholy, Robijaona; Emmanue, Andrianarivo; Amelie, Raharisololalao; Martin, Marie-Therese; Koto-te-Nyiwa, Ngbolua

2013-10-01

To validate scientifically the traditional use of Salacia leptoclada Tul. (Celastraceae) (S. leptoclada) and to isolate and elucidate the structure of the biologically active compound. Bioassay-guided fractionation of the acetonic extract of the stem barks of S. leptoclada was carried out by a combination of chromatography technique and biological experiments in viro using Plasmodium falciparum and P388 leukemia cell lines as models. The structure of the biologically active pure compound was elucidated by 1D and 2D NMR spectroscopy and mass spectrometry. Biological screening of S. leptoclada extracts resulted in the isolation of a pentacyclic triterpenic quinone methide. The pure compound exhibited both in vitro a cytotoxic effect on murine P388 leukemia cells with IC50 value of (0.041±0.020) μg/mL and an antiplasmodial activity against the chloroquine-resistant strain FC29 of Plasmodium falciparum with an IC50 value of (0.052±0.030) μg/mL. Despite this interesting anti-malarial property of the lead compound, the therapeutic index was weak (0.788). In the best of our knowledge, the quinone methide pentacyclic triterpenoid derivative compound is reported for the first time in S. leptoclada. The results suggest that furthers studies involving antineoplastic activity is needed for the development of this lead compound as anticancer drug. Copyright © 2013 Asian Pacific Tropical Biomedical Magazine. Published by Elsevier B.V. All rights reserved.

Architecture-independent power bound for vibration energy harvesters

International Nuclear Information System (INIS)

Halvorsen, E; Le, C P; Mitcheson, P D; Yeatman, E M

2013-01-01

The maximum output power of energy harvesters driven by harmonic vibrations is well known for a range of specific harvester architectures. An architecture-independent bound based on the mechanical input-power also exists and gives a strict limit on achievable power with one mechanical degree of freedom, but is a least upper bound only for lossless devices. We report a new theoretical bound on the output power of vibration energy harvesters that includes parasitic, linear mechanical damping while still being architecture independent. This bound greatly improves the previous bound at moderate force amplitudes and is compared to the performance of established harvester architectures which are shown to agree with it in limiting cases. The bound is a hard limit on achievable power with one mechanical degree of freedom and can not be circumvented by transducer or power-electronic-interface design

Uniform bounds for Black--Scholes implied volatility

OpenAIRE

Tehranchi, Michael R.

2015-01-01

In this note, Black--Scholes implied volatility is expressed in terms of various optimisation problems. From these representations, upper and lower bounds are derived which hold uniformly across moneyness and call price. Various symmetries of the Black--Scholes formula are exploited to derive new bounds from old. These bounds are used to reprove asymptotic formulae for implied volatility at extreme strikes and/or maturities.

Simulation bounds for system availability

International Nuclear Information System (INIS)

Tietjen, G.L.; Waller, R.A.

1976-01-01

System availability is a dominant factor in the practicality of nuclear power electrical generating plants. A proposed model for obtaining either lower bounds or interval estimates on availability uses observed data on ''n'' failure-to-repair cycles of the system to estimate the parameters in the time-to-failure and time-to-repair models. These estimates are then used in simulating failure/repair cycles of the system. The availability estimate is obtained for each of 5000 samples of ''n'' failure/repair cycles to form a distribution of estimates. Specific percentile points of those simulated distributions are selected as lower simulation bounds or simulation interval bounds for the system availability. The method is illustrated with operational data from two nuclear plants for which an exponential time-to-failure and a lognormal time-to-repair are assumed

Safety of pyrroloquinoline quinone disodium salt as a novel food pursuant to Regulation (EC) No 258/97

DEFF Research Database (Denmark)

Sjödin, Anders Mikael

2017-01-01

Following a request from the European Commission, the EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA) was asked to deliver an opinion on pyrroloquinoline quinone disodium salt (PQQ), trade name BioPQQTM, as a novel food pursuant to Regulation (EC) No 258/97. PQQ is produced...... by fermentation using Hyphomicrobium denitrificans CK-275 and purification process. PQQ has a minimum purity of 99.0%. The information provided on the composition, specifications, batch-to-batch variability, stability and production process of PQQ is sufficient and does not raise safety concerns. The applicant...... intends to market PQQ for use in food supplements for healthy adults, except pregnant and lactating women, at a maximum proposed level of consumption of 20 mg/day (corresponding to 0.29 mg/kg bw per day for a 70-kg person). The proposed level of consumption is at least 250 times higher than the estimated...

Bounds on fluid permeability for viscous flow through porous media

International Nuclear Information System (INIS)

Berryman, J.G.

1985-01-01

General properties of variational bounds on Darcy's constant for slow viscous flow through porous media are studied. The bounds are also evaluated numerically for the penetrable sphere model. The bound of Doi depending on two-point correlations and the analytical bound of Weissberg and Prager give comparable results in the low density limit but the analytical bound is superior for higher densities. Prager's bound depending on three-point correlation functions is worse than the analytical bound at low densities but better (although comparable to it) at high densities. A procedure for methodically improving Prager's three point bound is presented. By introducing a Gaussian trial function, the three-point bound is improved by an order of magnitude for moderate values of porosity. The new bounds are comparable in magnitude to the Kozeny--Carman empirical relation for porous materials

Cyanide as a copper and quinone-directed inhibitor of amine oxidases from pea seedlings ( Pisum sativum) and Arthrobacter globiformis: evidence for both copper coordination and cyanohydrin derivatization of the quinone cofactor.

Science.gov (United States)

Shepard, Eric M; Juda, Gregory A; Ling, Ke-Qing; Sayre, Lawrence M; Dooley, David M

2004-04-01

The interactions of cyanide with two copper-containing amine oxidases (CuAOs) from pea seedlings (PSAO) and the soil bacterium Arthrobacter globiformis (AGAO) have been investigated by spectroscopic and kinetic techniques. Previously, we rationalized the effects of azide and cyanide for several CuAOs in terms of copper coordination by these exogenous ligands and their effects on the internal redox equilibrium TPQ(amr)-Cu(II) right harpoon over left harpoon TPQ(sq)-Cu(I). The mechanism of cyanide inhibition was proposed to occur through complexation to Cu(I), thereby directly competing with O(2) for reoxidation of TPQ. Although cyanide readily and reversibly reacts with quinones, no direct spectroscopic evidence for cyanohydrin derivatization of TPQ has been previously documented for CuAOs. This work describes the first direct spectroscopic evidence, using both model and enzyme systems, for cyanohydrin derivatization of TPQ. K(d) values for Cu(II)-CN(-) and Cu(I)-CN(-), as well as the K(i) for cyanide inhibition versus substrate amine, are reported for PSAO and AGAO. In spite of cyanohydrin derivatization of the TPQ cofactor in these enzymes, the uncompetitive inhibition of amine oxidation is determined to arise almost exclusively through CN(-) complexation of Cu(I).

Lower bound on inconclusive probability of unambiguous discrimination

International Nuclear Information System (INIS)

Feng Yuan; Zhang Shengyu; Duan Runyao; Ying Mingsheng

2002-01-01

We derive a lower bound on the inconclusive probability of unambiguous discrimination among n linearly independent quantum states by using the constraint of no signaling. It improves the bound presented in the paper of Zhang, Feng, Sun, and Ying [Phys. Rev. A 64, 062103 (2001)], and when the optimal discrimination can be reached, these two bounds coincide with each other. An alternative method of constructing an appropriate measurement to prove the lower bound is also presented

Models and Techniques for Proving Data Structure Lower Bounds

DEFF Research Database (Denmark)

Larsen, Kasper Green

In this dissertation, we present a number of new techniques and tools for proving lower bounds on the operational time of data structures. These techniques provide new lines of attack for proving lower bounds in both the cell probe model, the group model, the pointer machine model and the I...... bound of tutq = (lgd􀀀1 n). For ball range searching, we get a lower bound of tutq = (n1􀀀1=d). The highest previous lower bound proved in the group model does not exceed ((lg n= lg lg n)2) on the maximum of tu and tq. Finally, we present a new technique for proving lower bounds....../O-model. In all cases, we push the frontiers further by proving lower bounds higher than what could possibly be proved using previously known techniques. For the cell probe model, our results have the following consequences: The rst (lg n) query time lower bound for linear space static data structures...

Stacked spheres and lower bound theorem

Indian Academy of Sciences (India)

BASUDEB DATTA

2011-11-20

Nov 20, 2011 ... Preliminaries. Lower bound theorem. On going work. Definitions. An n-simplex is a convex hull of n + 1 affinely independent points. (called vertices) in some Euclidean space R. N . Stacked spheres and lower bound theorem. Basudeb Datta. Indian Institute of Science. 2 / 27 ...

Exponential Lower Bounds For Policy Iteration

OpenAIRE

Fearnley, John

2010-01-01

We study policy iteration for infinite-horizon Markov decision processes. It has recently been shown policy iteration style algorithms have exponential lower bounds in a two player game setting. We extend these lower bounds to Markov decision processes with the total reward and average-reward optimality criteria.

An upper bound on Q-star masses

International Nuclear Information System (INIS)

Hochron, D.R.; Selipsky, S.B.

1992-06-01

Q-stars (the gravitational generalization of Q-balls, strongly bound bulk matter that an appear in field theories of strongly interacting hadrons) are the only known impact objects consistent with the known bulk structure of nuclei and chiral symmetry that evade the Rhoades-Ruffini upper bound of 3.2M circle-dot . Generic bounds are quite weak: M Q-star circle-dot . If, however, we assume that the 1.558 ms pulsar is a Q-star, equilibrium. A stability criteria of rotating fluids place a much stronger upper bound of M c ≤ 5.3M circle-dot on such models under certain special assumptions. This has important implications for heavy compact objects such as Cygnus X-1

Upper bounds for reversible circuits based on Young subgroups

DEFF Research Database (Denmark)

Abdessaied, Nabila; Soeken, Mathias; Thomsen, Michael Kirkedal

2014-01-01

We present tighter upper bounds on the number of Toffoli gates needed in reversible circuits. Both multiple controlled Toffoli gates and mixed polarity Toffoli gates have been considered for this purpose. The calculation of the bounds is based on a synthesis approach based on Young subgroups...... that results in circuits using a more generalized gate library. Starting from an upper bound for this library we derive new bounds which improve the existing bound by around 77%....

A new cytotoxic sesquiterpene quinone produced by Penicillium sp. F00120 isolated from a deep sea sediment sample.

Science.gov (United States)

Lin, Xiuping; Zhou, Xuefeng; Wang, Fazuo; Liu, Kaisheng; Yang, Bin; Yang, Xianwen; Peng, Yan; Liu, Juan; Ren, Zhe; Liu, Yonghong

2012-01-01

A new fungal strain, displaying strong toxic activity against brine shrimp larvae, was isolated from a deep sea sediment sample collected at a depth of 1300 m. The strain, designated as F00120, was identified as a member of the genus Penicillium on the basis of morphology and ITS sequence analysis. One new sesquiterpene quinone, named penicilliumin A (1), along with two known compounds ergosterol (2) and ergosterol peroxide (3), were isolated and purified from the cultures of F00120 by silica gel column, Sephadex LH-20 column, and preparative thin layer chromatography. Their structures were elucidated by detailed nuclear magnetic resonance (NMR) and mass spectroscopic (MS) analysis as well as comparison with literature data. The new compound penicilliumin A inhibited in vitro proliferation of mouse melanoma (B16), human melanoma (A375), and human cervical carcinoma (Hela) cell lines moderately.

NAD(P)H:quinone oxidoreductase expression in Cyp1a-knockout and CYP1A-humanized mouse lines and its effect on bioactivation of the carcinogen aristolochic acid I

Energy Technology Data Exchange (ETDEWEB)

Levova, Katerina; Moserova, Michaela [Department of Biochemistry, Faculty of Science, Charles University, Prague (Czech Republic); Nebert, Daniel W. [Department of Environmental Health, University of Cincinnati Medical Center, Cincinnati (United States); Phillips, David H. [Analytical and Environmental Sciences Division, MRC-HPA Centre for Environment and Health, King' s College London, London (United Kingdom); Frei, Eva [Division of Preventive Oncology, National Center for Tumor Diseases, German Cancer Research Center (DKFZ), Heidelberg (Germany); Schmeiser, Heinz H. [Research Group Genetic Alterations in Carcinogenesis, German Cancer Research Center (DKFZ), Heidelberg (Germany); Arlt, Volker M. [Analytical and Environmental Sciences Division, MRC-HPA Centre for Environment and Health, King' s College London, London (United Kingdom); Stiborova, Marie, E-mail: stiborov@natur.cuni.cz [Department of Biochemistry, Faculty of Science, Charles University, Prague (Czech Republic)

2012-12-15

Aristolochic acid causes a specific nephropathy (AAN), Balkan endemic nephropathy, and urothelial malignancies. Using Western blotting suitable to determine protein expression, we investigated in several transgenic mouse lines expression of NAD(P)H:quinone oxidoreductase (NQO1)—the most efficient cytosolic enzyme that reductively activates aristolochic acid I (AAI). The mouse tissues used were from previous studies [Arlt et al., Chem. Res. Toxicol. 24 (2011) 1710; Stiborova et al., Toxicol. Sci. 125 (2012) 345], in which the role of microsomal cytochrome P450 (CYP) enzymes in AAI metabolism in vivo had been determined. We found that NQO1 levels in liver, kidney and lung of Cyp1a1(−/−), Cyp1a2(−/−) and Cyp1a1/1a2(−/−) knockout mouse lines, as well as in two CYP1A-humanized mouse lines harboring functional human CYP1A1 and CYP1A2 and lacking the mouse Cyp1a1/1a2 orthologs, differed from NQO1 levels in wild-type mice. NQO1 protein and enzymic activity were induced in hepatic and renal cytosolic fractions isolated from AAI-pretreated mice, compared with those in untreated mice. Furthermore, this increase in hepatic NQO1 enzyme activity was associated with bioactivation of AAI and elevated AAI-DNA adduct levels in ex vivo incubations of cytosolic fractions with DNA and AAI. In conclusion, AAI appears to increase its own metabolic activation by inducing NQO1, thereby enhancing its own genotoxic potential. Highlights: ► NAD(P)H:quinone oxidoreductase expression in Cyp1a knockout and humanized CYP1A mice ► Reductive activation of the nephrotoxic and carcinogenic aristolochic acid I (AAI) ► NAD(P)H:quinone oxidoreductase is induced in mice treated with AAI. ► Induced hepatic enzyme activity resulted in elevated AAI-DNA adduct levels.

NAD(P)H:quinone oxidoreductase expression in Cyp1a-knockout and CYP1A-humanized mouse lines and its effect on bioactivation of the carcinogen aristolochic acid I

International Nuclear Information System (INIS)

Levova, Katerina; Moserova, Michaela; Nebert, Daniel W.; Phillips, David H.; Frei, Eva; Schmeiser, Heinz H.; Arlt, Volker M.; Stiborova, Marie

2012-01-01

Aristolochic acid causes a specific nephropathy (AAN), Balkan endemic nephropathy, and urothelial malignancies. Using Western blotting suitable to determine protein expression, we investigated in several transgenic mouse lines expression of NAD(P)H:quinone oxidoreductase (NQO1)—the most efficient cytosolic enzyme that reductively activates aristolochic acid I (AAI). The mouse tissues used were from previous studies [Arlt et al., Chem. Res. Toxicol. 24 (2011) 1710; Stiborova et al., Toxicol. Sci. 125 (2012) 345], in which the role of microsomal cytochrome P450 (CYP) enzymes in AAI metabolism in vivo had been determined. We found that NQO1 levels in liver, kidney and lung of Cyp1a1(−/−), Cyp1a2(−/−) and Cyp1a1/1a2(−/−) knockout mouse lines, as well as in two CYP1A-humanized mouse lines harboring functional human CYP1A1 and CYP1A2 and lacking the mouse Cyp1a1/1a2 orthologs, differed from NQO1 levels in wild-type mice. NQO1 protein and enzymic activity were induced in hepatic and renal cytosolic fractions isolated from AAI-pretreated mice, compared with those in untreated mice. Furthermore, this increase in hepatic NQO1 enzyme activity was associated with bioactivation of AAI and elevated AAI-DNA adduct levels in ex vivo incubations of cytosolic fractions with DNA and AAI. In conclusion, AAI appears to increase its own metabolic activation by inducing NQO1, thereby enhancing its own genotoxic potential. Highlights: ► NAD(P)H:quinone oxidoreductase expression in Cyp1a knockout and humanized CYP1A mice ► Reductive activation of the nephrotoxic and carcinogenic aristolochic acid I (AAI) ► NAD(P)H:quinone oxidoreductase is induced in mice treated with AAI. ► Induced hepatic enzyme activity resulted in elevated AAI-DNA adduct levels.

Uniform Bounds for Black--Scholes Implied Volatility

OpenAIRE

Tehranchi, Michael Rummine

2016-01-01

In this note, Black--Scholes implied volatility is expressed in terms of various optimization problems. From these representations, upper and lower bounds are derived which hold uniformly across moneyness and call price. Various symmetries of the Black--Scholes formula are exploited to derive new bounds from old. These bounds are used to reprove asymptotic formulas for implied volatility at extreme strikes and/or maturities. the Society for Industrial and Applied Mathematics 10.1137/14095248X

Proximity effect tunneling into virtual bound state alloys

International Nuclear Information System (INIS)

Tang, I.M.; Roongkkeadsakoon, S.

1984-01-01

The effects of a narrow virtual bound state formed by transition metal impurities dissolved in the normal layer of a superconducting proximity effect sandwich are studied. Using standard renormalization techniques, we obtain the changes in the transition temperatures and the jumps in the specific heat at T/sub c/ as a function of the thickness of the normal layer, of the widths of the virtual bound states, and of the impurity concentrations. It is seen that narrow virtual bound states lead to decrease in the transition temperatures, while broad virtual bound states do not. It if further seen that the narrow virtual bound state causes the reduced specific heat jump at T/sub c/ to deviate from the BCS behavior expected of the pure sandwich

A strongly quasiconvex PAC-Bayesian bound

DEFF Research Database (Denmark)

Thiemann, Niklas; Igel, Christian; Wintenberger, Olivier

2017-01-01

We propose a new PAC-Bayesian bound and a way of constructing a hypothesis space, so that the bound is convex in the posterior distribution and also convex in a trade-off parameter between empirical performance of the posterior distribution and its complexity. The complexity is measured by the Ku...

Sharp bounds for periodic solutions of Lipschitzian differential equations

International Nuclear Information System (INIS)

Zevin, A A

2009-01-01

A general system of Lipschitzian differential equations, containing simultaneously terms without delay and with arbitrary constant and time-varying delays, is considered. For the autonomous case, a lower bound for the period of nonconstant periodic solutions, expressed in the respective supremum Lipschitz constants, is found. For nonautonomous periodic equations, explicit upper bounds for the amplitudes and maximum derivatives of periodic solutions are obtained. For all n ≥ 2, the bounds do not depend on n and, in general, are different from that for n = 1. All the bounds are sharp; they are attained in linear differential equations with piece-wise constant deviating arguments. A relation between the obtained bounds and the sharp bounds in other metrics is established

Bounds for nonlinear composites via iterated homogenization

Science.gov (United States)

Ponte Castañeda, P.

2012-09-01

Improved estimates of the Hashin-Shtrikman-Willis type are generated for the class of nonlinear composites consisting of two well-ordered, isotropic phases distributed randomly with prescribed two-point correlations, as determined by the H-measure of the microstructure. For this purpose, a novel strategy for generating bounds has been developed utilizing iterated homogenization. The general idea is to make use of bounds that may be available for composite materials in the limit when the concentration of one of the phases (say phase 1) is small. It then follows from the theory of iterated homogenization that it is possible, under certain conditions, to obtain bounds for more general values of the concentration, by gradually adding small amounts of phase 1 in incremental fashion, and sequentially using the available dilute-concentration estimate, up to the final (finite) value of the concentration (of phase 1). Such an approach can also be useful when available bounds are expected to be tighter for certain ranges of the phase volume fractions. This is the case, for example, for the "linear comparison" bounds for porous viscoplastic materials, which are known to be comparatively tighter for large values of the porosity. In this case, the new bounds obtained by the above-mentioned "iterated" procedure can be shown to be much improved relative to the earlier "linear comparison" bounds, especially at low values of the porosity and high triaxialities. Consistent with the way in which they have been derived, the new estimates are, strictly, bounds only for the class of multi-scale, nonlinear composites consisting of two well-ordered, isotropic phases that are distributed with prescribed H-measure at each stage in the incremental process. However, given the facts that the H-measure of the sequential microstructures is conserved (so that the final microstructures can be shown to have the same H-measure), and that H-measures are insensitive to length scales, it is conjectured

Four-quark bound states

International Nuclear Information System (INIS)

Zouzou, S.

1986-01-01

In the framework of simple non-relativistic potential models, we examine the system consisting of two quarks and two antiquarks with equal or unequal masses. We search for possible bound states below the threshold for the spontaneous dissociation into two mesons. We solve the four body problem by empirical or systematic variational methods and we include the virtual meson-meson components of the wave function. With standard two-body potentials, there is no proliferation of multiquarks. With unequal quark masses, we obtain however exotic (anti Qanti Qqq) bound states with a baryonic antidiquark-quark-quark structure very analogous to the heavy flavoured (Q'qq) baryons. (orig.)

Thermalization Time Bounds for Pauli Stabilizer Hamiltonians

Science.gov (United States)

Temme, Kristan

2017-03-01

We prove a general lower bound to the spectral gap of the Davies generator for Hamiltonians that can be written as the sum of commuting Pauli operators. These Hamiltonians, defined on the Hilbert space of N-qubits, serve as one of the most frequently considered candidates for a self-correcting quantum memory. A spectral gap bound on the Davies generator establishes an upper limit on the life time of such a quantum memory and can be used to estimate the time until the system relaxes to thermal equilibrium when brought into contact with a thermal heat bath. The bound can be shown to behave as {λ ≥ O(N^{-1} exp(-2β overline{ɛ}))}, where {overline{ɛ}} is a generalization of the well known energy barrier for logical operators. Particularly in the low temperature regime we expect this bound to provide the correct asymptotic scaling of the gap with the system size up to a factor of N -1. Furthermore, we discuss conditions and provide scenarios where this factor can be removed and a constant lower bound can be proven.

Information-Theoretic Bounded Rationality and ε-Optimality

Directory of Open Access Journals (Sweden)

Daniel A. Braun

2014-08-01

Full Text Available Bounded rationality concerns the study of decision makers with limited information processing resources. Previously, the free energy difference functional has been suggested to model bounded rational decision making, as it provides a natural trade-off between an energy or utility function that is to be optimized and information processing costs that are measured by entropic search costs. The main question of this article is how the information-theoretic free energy model relates to simple ε-optimality models of bounded rational decision making, where the decision maker is satisfied with any action in an ε-neighborhood of the optimal utility. We find that the stochastic policies that optimize the free energy trade-off comply with the notion of ε-optimality. Moreover, this optimality criterion even holds when the environment is adversarial. We conclude that the study of bounded rationality based on ε-optimality criteria that abstract away from the particulars of the information processing constraints is compatible with the information-theoretic free energy model of bounded rationality.

Justification of a "Crucial" Experiment: Parity Nonconservation.

Science.gov (United States)

Franklin, Allan; Smokler, Howard

1981-01-01

Presents history, nature of evidence evaluated, and philosophical questions to justify the view that experiments on parity nonconservation were "crucial" experiments in the sense that they decided unambiguously and within a short period of time for the appropriate scientific community, between two or more competing theories or classes of theories.…

Time-stepping approach for solving upper-bound problems: Application to two-dimensional Rayleigh-Bénard convection

Science.gov (United States)

Wen, Baole; Chini, Gregory P.; Kerswell, Rich R.; Doering, Charles R.

2015-10-01

An alternative computational procedure for numerically solving a class of variational problems arising from rigorous upper-bound analysis of forced-dissipative infinite-dimensional nonlinear dynamical systems, including the Navier-Stokes and Oberbeck-Boussinesq equations, is analyzed and applied to Rayleigh-Bénard convection. A proof that the only steady state to which this numerical algorithm can converge is the required global optimal of the relevant variational problem is given for three canonical flow configurations. In contrast with most other numerical schemes for computing the optimal bounds on transported quantities (e.g., heat or momentum) within the "background field" variational framework, which employ variants of Newton's method and hence require very accurate initial iterates, the new computational method is easy to implement and, crucially, does not require numerical continuation. The algorithm is used to determine the optimal background-method bound on the heat transport enhancement factor, i.e., the Nusselt number (Nu), as a function of the Rayleigh number (Ra), Prandtl number (Pr), and domain aspect ratio L in two-dimensional Rayleigh-Bénard convection between stress-free isothermal boundaries (Rayleigh's original 1916 model of convection). The result of the computation is significant because analyses, laboratory experiments, and numerical simulations have suggested a range of exponents α and β in the presumed Nu˜PrαRaβ scaling relation. The computations clearly show that for Ra≤1010 at fixed L =2 √{2 },Nu≤0.106 Pr0Ra5/12 , which indicates that molecular transport cannot generally be neglected in the "ultimate" high-Ra regime.

Ultrafast Adiabatic Photodehydration of 2-Hydroxymethylphenol and the Formation of Quinone Methide.

Science.gov (United States)

Škalamera, Đani; Antol, Ivana; Mlinarić-Majerski, Kata; Vančik, Hrvoj; Phillips, David Lee; Ma, Jiani; Basarić, Nikola

2018-04-20

The photochemical reactivity of 2-hydroxymethylphenol (1) was investigated experimentally by photochemistry under cryogenic conditions, by detecting reactive intermediates by IR spectroscopy, and by using nanosecond and femtosecond transient absorption spectroscopic methods in solution at room temperature. In addition, theoretical studies were performed to facilitate the interpretation of the experimental results and also to simulate the reaction pathway to obtain a better understanding of the reaction mechanism. The main finding of this work is that photodehydration of 1 takes place in an ultrafast adiabatic photochemical reaction without any clear intermediate, delivering quinone methide (QM) in the excited state. Upon photoexcitation to a higher vibrational level of the singlet excited state, 1 undergoes vibrational relaxation leading to two photochemical pathways, one by which synchronous elimination of H 2 O gives QM 2 in its S 1 state and the other by which homolytic cleavage of the phenolic O-H bond produces a phenoxyl radical (S 0 ). Both are ultrafast processes that occur within a picosecond. The excited state of QM 2 (S 1 ) probably deactivates to S 0 through a conical intersection to give QM 2 (S 0 ), which subsequently delivers benzoxete 4. Elucidation of the reaction mechanisms for the photodehydration of phenols by which QMs are formed is important to tune the reactivity of QMs with DNA and proteins for the potential application of QMs in medicine as therapeutic agents. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Correlation of quinone reductase activity and allyl isothiocyanate formation among different genotypes and grades of horseradish roots.

Science.gov (United States)

Ku, Kang-Mo; Jeffery, Elizabeth H; Juvik, John A; Kushad, Mosbah M

2015-03-25

Horseradish (Armoracia rusticana) is a perennial crop and its ground root tissue is used in condiments because of the pungency of the glucosinolate (GS)-hydrolysis products allyl isothiocyanate (AITC) and phenethyl isothiocyanate (PEITC) derived from sinigrin and gluconasturtiin, respectively. Horseradish roots are sold in three grades: U.S. Fancy, U.S. No. 1, and U.S. No. 2 according to the USDA standards. These grading standards are primarily based on root diameter and length. There is little information on whether root grades vary in their phytochemical content or potential health promoting properties. This study measured GS, GS-hydrolysis products, potential anticancer activity (as quinone reductase inducing activity), total phenolic content, and antioxidant activities from different grades of horseradish accessions. U.S. Fancy showed significantly higher sinigrin and AITC concentrations than U.S. No. 1 ,whereas U.S. No. 1 showed significantly higher concentrations of 1-cyano 2,3-epithiopropane, the epithionitrile hydrolysis product of sinigrin, and significantly higher total phenolic concentrations than U.S. Fancy.

Bounded-Angle Iterative Decoding of LDPC Codes

Science.gov (United States)

Dolinar, Samuel; Andrews, Kenneth; Pollara, Fabrizio; Divsalar, Dariush

2009-01-01

Bounded-angle iterative decoding is a modified version of conventional iterative decoding, conceived as a means of reducing undetected-error rates for short low-density parity-check (LDPC) codes. For a given code, bounded-angle iterative decoding can be implemented by means of a simple modification of the decoder algorithm, without redesigning the code. Bounded-angle iterative decoding is based on a representation of received words and code words as vectors in an n-dimensional Euclidean space (where n is an integer).

Unexpected strong attraction in the presence of continuum bound state

International Nuclear Information System (INIS)

Delfino, A.; Frederico, T.

1992-06-01

The result of few-particle ground-state calculation employing a two-particle non-local potential supporting a continuum bound state in addition to a negative-energy bound state has occasionally revealed unexpected large attraction in producing a very strongly bound ground state. In the presence of the continuum bound state the difference of phase shift between zero and infinite energies has an extra jump of φ as in the presence of an additional bound state. The wave function of the continuum bound state is identical with that of a strongly bound negative-energy state, which leads us to postulate a pseudo bound state in the two-particle system in order to explain the unexpected attraction. The role of the Pauli forbidden states is expected to be similar to these pseudo states. (author)

On the Feng-Rao bound for generalized hamming weights

DEFF Research Database (Denmark)

Geil, Hans Olav; Thommesen, Christian

2006-01-01

The Feng-Rao bound gives good estimates of the minimum distance of a large class of codes. In this work we are concerned with the problem of how to extend the Feng-Rao bound so that it deals with all the generalized Hamming weights. The problem was solved by Heijnen and Pellikaan in [7] for a large...... family of codes that includes the duals of one-point geometric Goppa codes and the q-ary Reed-Muller codes, but not the Feng-Rao improved such ones. We show that Heijnen and Pellikaan's results holds for the more general class of codes for which the traditional Feng-Rao bound can be applied. We also...... establish the connection to the Shibuya-Sakaniwa bound for generalized Hamming weights ([15], [16], [17], [18], [19] and [20]). More precisely we show that the Shibuya-Sakaniwa bound is a consequence of the extended Feng-Rao bound. In particular the extended Feng-Rao bound gives always at least as good...

On the Feng-Rao bound for generalized Hamming weights

DEFF Research Database (Denmark)

Geil, Olav; Thommesen, Christian

2005-01-01

The Feng-Rao bound gives good estimates of the minimum distance of a large class of codes. In this work we are concerned with the problem of how to extend the Feng-Rao bound so that it deals with all the generalized Hamming weights. The problem was solved by Heijnen and Pellikaan in [7] for a large...... family of codes that includes the duals of one-point geometric Goppa codes and the q-ary Reed-Muller codes, but not the Feng-Rao improved such ones. We show that Heijnen and Pellikaan’s results holds for the more general class of codes for which the traditional Feng-Rao bound can be applied. We also...... establish the connection to the Shibuya-Sakaniwa bound for generalized Hamming weights ([15], [16], [17], [18], [19] and [20]). More precisely we show that the Shibuya-Sakaniwa bound is a consequence of the extended Feng-Rao bound. In particular the extended Feng-Rao bound gives always at least as good...

Remarks on Bousso's covariant entropy bound

CERN Document Server

Mayo, A E

2002-01-01

Bousso's covariant entropy bound is put to the test in the context of a non-singular cosmological solution of general relativity found by Bekenstein. Although the model complies with every assumption made in Bousso's original conjecture, the entropy bound is violated due to the occurrence of negative energy density associated with the interaction of some the matter components in the model. We demonstrate how this property allows for the test model to 'elude' a proof of Bousso's conjecture which was given recently by Flanagan, Marolf and Wald. This corroborates the view that the covariant entropy bound should be applied only to stable systems for which every matter component carries positive energy density.

Generalized Hofmann quantum process fidelity bounds for quantum filters

Science.gov (United States)

Sedlák, Michal; Fiurášek, Jaromír

2016-04-01

We propose and investigate bounds on the quantum process fidelity of quantum filters, i.e., probabilistic quantum operations represented by a single Kraus operator K . These bounds generalize the Hofmann bounds on the quantum process fidelity of unitary operations [H. F. Hofmann, Phys. Rev. Lett. 94, 160504 (2005), 10.1103/PhysRevLett.94.160504] and are based on probing the quantum filter with pure states forming two mutually unbiased bases. Determination of these bounds therefore requires far fewer measurements than full quantum process tomography. We find that it is particularly suitable to construct one of the probe bases from the right eigenstates of K , because in this case the bounds are tight in the sense that if the actual filter coincides with the ideal one, then both the lower and the upper bounds are equal to 1. We theoretically investigate the application of these bounds to a two-qubit optical quantum filter formed by the interference of two photons on a partially polarizing beam splitter. For an experimentally convenient choice of factorized input states and measurements we study the tightness of the bounds. We show that more stringent bounds can be obtained by more sophisticated processing of the data using convex optimization and we compare our methods for different choices of the input probe states.

In vivo relevance of two critical levels for NAD(P)H:quinone oxidoreductase (NQO1)-mediated cellular protection against electrophile toxicity found in vitro.

Science.gov (United States)

de Haan, Laura H J; Pot, Gerda K; Aarts, Jac M M J G; Rietjens, Ivonne M C M; Alink, Gerrit M

2006-08-01

NAD(P)H:quinone oxidoreductase (NQO1)-mediated detoxification of quinones is suggested to be involved in cancer prevention. In the present study, using transfected CHO cells, it was demonstrated that the relation between NQO1 activity and the resulting protection against the cytotoxicity of menadione shows a steep dose-response curve revealing a 'lower protection threshold' of 0.5mumol DCPIP/min/mg protein and an 'upper protection threshold' at 1mumol DCPIP/min/mg protein. In an additional in vivo experiment it was investigated how both in vitro critical activity levels of NQO1, relate to NQO1 activities in mice and man, either without or upon induction of the enzyme by butylated hydroxyanisol (BHA) or indole-3-carbinol (I(3)C). Data from an experiment with CD1 mice revealed that base-line NQO1 levels in liver, kidney, small intestine, colon and lung are generally below the observed 'lower protection threshold' in vitro, this also holds for most human tissue S-9 samples. To achieve NQO1 levels above this 'lower protection threshold' will require 5-20 fold NQO1 induction. Discussion focuses on the relevance of the in vitro NQO1 activity thresholds for the in vivo situation. We conclude that increased protection against menadione toxicity can probably not be achieved by NQO1 induction but should be achieved by other mechanisms. Whether this conclusion also holds for other electrophiles and the in vivo situation awaits further definition of their NQO1 protection thresholds.

Twisting, supercoiling and stretching in protein bound DNA

Science.gov (United States)

Lam, Pui-Man; Zhen, Yi

2018-04-01

We have calculated theoretical results for the torque and slope of the twisted DNA, with various proteins bound on it, using the Neukirch-Marko model, in the regime where plectonemes exist. We found that the torque in the protein bound DNA decreases compared to that in the bare DNA. This is caused by the decrease in the free energy g(f) , and hence the smaller persistence lengths, in the case of protein bound DNA. We hope our results will encourage experimental investigations of supercoiling in protein bound DNA, which can provide further tests of the Neukirch-Marko model.

The bound state problem and quark confinement

International Nuclear Information System (INIS)

Chaichian, M.; Demichev, A.P.; Nelipa, N.F.

1980-01-01

A quantum field-theoretic model in which quark is confined is considered. System of equations for the Green functions of colour singlet and octet bound states is obtained. The method is based on the nonperturbative Schwinger-Dyson equations with the use of Slavnov-Taylor identities. It is shown that in the framework of the model if there exist singlet, then also exist octet bound states of the quark-antiquark system. Thus in general, confinement of free quarks does not mean absence of their coloured bound states. (author)

``Carbon Credits'' for Resource-Bounded Computations Using Amortised Analysis

Science.gov (United States)

Jost, Steffen; Loidl, Hans-Wolfgang; Hammond, Kevin; Scaife, Norman; Hofmann, Martin

Bounding resource usage is important for a number of areas, notably real-time embedded systems and safety-critical systems. In this paper, we present a fully automatic static type-based analysis for inferring upper bounds on resource usage for programs involving general algebraic datatypes and full recursion. Our method can easily be used to bound any countable resource, without needing to revisit proofs. We apply the analysis to the important metrics of worst-case execution time, stack- and heap-space usage. Our results from several realistic embedded control applications demonstrate good matches between our inferred bounds and measured worst-case costs for heap and stack usage. For time usage we infer good bounds for one application. Where we obtain less tight bounds, this is due to the use of software floating-point libraries.

Improved rigorous upper bounds for transport due to passive advection described by simple models of bounded systems

International Nuclear Information System (INIS)

Kim, Chang-Bae; Krommes, J.A.

1988-08-01

The work of Krommes and Smith on rigorous upper bounds for the turbulent transport of a passively advected scalar [/ital Ann. Phys./ 177:246 (1987)] is extended in two directions: (1) For their ''reference model,'' improved upper bounds are obtained by utilizing more sophisticated two-time constraints which include the effects of cross-correlations up to fourth order. Numerical solutions of the model stochastic differential equation are also obtained; they show that the new bounds compare quite favorably with the exact results, even at large Reynolds and Kubo numbers. (2) The theory is extended to take account of a finite spatial autocorrelation length L/sub c/. As a reasonably generic example, the problem of particle transport due to statistically specified stochastic magnetic fields in a collisionless turbulent plasma is revisited. A bound is obtained which reduces for small L/sub c/ to the quasilinear limit and for large L/sub c/ to the strong turbulence limit, and which provides a reasonable and rigorous interpolation for intermediate values of L/sub c/. 18 refs., 6 figs

Heritable Variation in Quinone-Induced Haustorium Development in the Parasitic Plant Triphysaria1

Science.gov (United States)

Jamison, Denneal S.; Yoder, John I.

2001-01-01

We are using the facultative hemiparasite, Triphysaria, as a model for studying host-parasite signaling in the Scrophulariaceae. Parasitic members of this family form subterranean connections, or haustoria, on neighboring host roots to access host water and nutrients. These parasitic organs develop in response to haustorial-inducing factors contained in host root exudates. A well-characterized inducing factor, 2, 6-dimethoxy-p-benzoquinone (DMBQ), can be used to trigger in vitro haustorium formation in the roots of Triphysaria. We have assayed three species, Triphysaria eriantha (Benth.) Chuang and Heckard, Triphysaria pusilla (Benth.) Chuang and Heckard, and Triphysaria versicolor Fischer and C. Meyer, for haustorium development in response to DMBQ. There were significant differences between the species in their ability to recognize and respond to this quinone. Ninety percent of T. versicolor individuals responded, whereas only 40% of T. pusilla and less than 10% of T. eriantha formed haustoria. Within field collections of self-pollinating T. pusilla, differential responsiveness to DMBQ was seen in distinct maternal families. Assaying haustorium development in subsequent generations of self-pollinated T. pusilla showed that DMBQ responsiveness was heritable. Reciprocal crosses between T. eriantha and T. versicolor demonstrated that DMBQ responsiveness was influenced by maternal factors. These results demonstrate heritable, natural variation in the recognition of a haustorial-inducing factor by a parasitic member of the Scrophulariaceae. PMID:11299366

Effect of soil-bound residues of malathion on microbial activities

International Nuclear Information System (INIS)

Hussain, A.; Iqbal, Z.; Asi, M.R.; Tahira, R.; Chudhary, J.A.

2001-01-01

The effect of soil-bound residues of malathion on CO/sub 2/ evolution, dehydrogenase activity and some nitrogen transformations in a loam soil was investigated under laboratory conditions. The soil samples containing bound residues arising from 10 mg g-1 of the applied malathion were mixed in equal quantity with fresh soil and compared with solvent extracted control soil without bound residues (extracted in the same way as soil containing bound residues). Another control comprising un extracted fresh soil without bound residues was also kept to study the effect of solvent extraction on the biological activity. Rate of Carbon mineralization (CO/sub 2/ evolution) was decreased in the presence of soil-bound residues of malathion. Bound residues also affected dehydrogenase activity of soil. Over 40% inhibition of dehydrogenase activity was observed after 4 days and the inhibition persisted at least for 12 days. Nitrogen mineralization was stimulated in soil containing bound residues of malathion and this stimulatory effect increased with time of incubation. Nitrification was partially inhibited in the presence of soil-bound residues of malathion. The inhibitory effect of the soil-bound residues on nitrification did not show much variation with time. The soil-bound residues did not affect denitrification rate (N/sub 2/O evolution). Nitrogen fixation (acetylene reduction) was partially inhibited in soil amended with bound residues of malathion and the inhibitory effect persisted for at least one week. In general, soil bound residues of malathion inhibited CO/sub 2/ evolution, dehydrogenase activity, nitrification and nitrogen fixation while mineralization of nitrogen was stimulated. Denitrification was not affected by the applied insecticide. (author)

Generalized surface tension bounds in vacuum decay

Science.gov (United States)

Masoumi, Ali; Paban, Sonia; Weinberg, Erick J.

2018-02-01

Coleman and De Luccia (CDL) showed that gravitational effects can prevent the decay by bubble nucleation of a Minkowski or AdS false vacuum. In their thin-wall approximation this happens whenever the surface tension in the bubble wall exceeds an upper bound proportional to the difference of the square roots of the true and false vacuum energy densities. Recently it was shown that there is another type of thin-wall regime that differs from that of CDL in that the radius of curvature grows substantially as one moves through the wall. Not only does the CDL derivation of the bound fail in this case, but also its very formulation becomes ambiguous because the surface tension is not well defined. We propose a definition of the surface tension and show that it obeys a bound similar in form to that of the CDL case. We then show that both thin-wall bounds are special cases of a more general bound that is satisfied for all bounce solutions with Minkowski or AdS false vacua. We discuss the limit where the parameters of the theory attain critical values and the bound is saturated. The bounce solution then disappears and a static planar domain wall solution appears in its stead. The scalar field potential then is of the form expected in supergravity, but this is only guaranteed along the trajectory in field space traced out by the bounce.

Bound entanglement and local realism

International Nuclear Information System (INIS)

Kaszlikowski, Dagomir; Zukowski, Marek; Gnacinski, Piotr

2002-01-01

We show using a numerical approach, which gives necessary and sufficient conditions for the existence of local realism, that the bound entangled state presented in Bennett et al. [Phys. Rev. Lett. 82, 5385 (1999)] admits a local and realistic description. We also find the lowest possible amount of some appropriate entangled state that must be ad-mixed to the bound entangled state so that the resulting density operator has no local and realistic description and as such can be useful in quantum communication and quantum computation

Inequalities and bounds for nucleon-nucleon scattering

International Nuclear Information System (INIS)

Ramandurai, K.S.

1979-08-01

The objective of this work is to derive model-independent inequalities and bounds for nucleon-nucleon elastic scattering amplitudes based on well-established theoretical principles and symmetries. Two classes of methods are used: algebraic and variational. In the algebraic part, the author derives inequalities and bounds for NN amplitudes and observables using their mutual relations and x symmetries. In the variational part, he employs Lagrange's method of undetermined multipliers to evaluate the bounds. He tests the predictions of a sample of proposed phase shifts at three different energies using the results obtained

Conductivity bound from dirty black holes

Energy Technology Data Exchange (ETDEWEB)

Bitaghsir Fadafan, Kazem, E-mail: bitaghsir@shahroodut.ac.ir

2016-11-10

We propose a lower bound of the dc electrical conductivity in strongly disordered, strongly interacting quantum field theories using holography. We study linear response of black holes with broken translational symmetry in Einstein–Maxwell-dilaton theories of gravity. Using the generalized Stokes equations at the horizon, we derive the lower bound of the electrical conductivity for the dual two dimensional disordered field theory.

Braneworld black holes and entropy bounds

Directory of Open Access Journals (Sweden)

Y. Heydarzade

2018-01-01

Full Text Available The Bousso's D-bound entropy for the various possible black hole solutions on a 4-dimensional brane is checked. It is found that the D-bound entropy here is apparently different from that of obtained for the 4-dimensional black hole solutions. This difference is interpreted as the extra loss of information, associated to the extra dimension, when an extra-dimensional black hole is moved outward the observer's cosmological horizon. Also, it is discussed that N-bound entropy is hold for the possible solutions here. Finally, by adopting the recent Bohr-like approach to black hole quantum physics for the excited black holes, the obtained results are written also in terms of the black hole excited states.

Classical Physics and the Bounds of Quantum Correlations.

Science.gov (United States)

Frustaglia, Diego; Baltanás, José P; Velázquez-Ahumada, María C; Fernández-Prieto, Armando; Lujambio, Aintzane; Losada, Vicente; Freire, Manuel J; Cabello, Adán

2016-06-24

A unifying principle explaining the numerical bounds of quantum correlations remains elusive, despite the efforts devoted to identifying it. Here, we show that these bounds are indeed not exclusive to quantum theory: for any abstract correlation scenario with compatible measurements, models based on classical waves produce probability distributions indistinguishable from those of quantum theory and, therefore, share the same bounds. We demonstrate this finding by implementing classical microwaves that propagate along meter-size transmission-line circuits and reproduce the probabilities of three emblematic quantum experiments. Our results show that the "quantum" bounds would also occur in a classical universe without quanta. The implications of this observation are discussed.

Photophysics of aggregated 9-methylthiacarbocyanine bound to polyanions

Science.gov (United States)

Chibisov, Alexander K.; Görner, Helmut

2002-05-01

The photophysical properties of 3,3 '-diethyl-9-methylthiacarbocyanine (DTC) were studied in the presence of polystyrene sulfonate (PSS), polyacrylic acid (PAA) and polymethacrylic acid (PMA). The absorption spectra reflect a monomer/dimer equilibrium in neat aqueous solution and a shift towards bound H-aggregates, bound dimers and bound monomers on increasing the ratio of polyanion residue to dye concentrations ( r). These equilibria also determine the photodeactivation modes of DTC. The fluorescence intensity is reduced, when dimers and aggregates are present and strongly enhanced for low dye loading ( r=10 4). In contrast, the quantum yield of intersystem crossing is enhanced for bound dimers ( r=10 3).

The algebras of bounded and essentially bounded Lebesgue measurable functions

Directory of Open Access Journals (Sweden)

Mortini Raymond

2017-04-01

Full Text Available Let X be a set in ℝn with positive Lebesgue measure. It is well known that the spectrum of the algebra L∞(X of (equivalence classes of essentially bounded, complex-valued, measurable functions on X is an extremely disconnected compact Hausdorff space.We show, by elementary methods, that the spectrum M of the algebra ℒb(X, ℂ of all bounded measurable functions on X is not extremely disconnected, though totally disconnected. Let ∆ = { δx : x ∈ X} be the set of point evaluations and let g be the Gelfand topology on M. Then (∆, g is homeomorphic to (X, Τdis,where Tdis is the discrete topology. Moreover, ∆ is a dense subset of the spectrum M of ℒb(X, ℂ. Finally, the hull h(I, (which is homeomorphic to M(L∞(X, of the ideal of all functions in ℒb(X, ℂ vanishing almost everywhere on X is a nowhere dense and extremely disconnected subset of the Corona M \\ ∆ of ℒb(X, ℂ.

Carbon Inputs From Riparian Vegetation Limit Oxidation of Physically Bound Organic Carbon Via Biochemical and Thermodynamic Processes: OC Oxidation Processes Across Vegetation

Energy Technology Data Exchange (ETDEWEB)

Graham, Emily B. [Pacific Northwest National Laboratory, Richland WA USA; Tfaily, Malak M. [Environmental Molecular Sciences Laboratory, Richland WA USA; Crump, Alex R. [Pacific Northwest National Laboratory, Richland WA USA; Goldman, Amy E. [Pacific Northwest National Laboratory, Richland WA USA; Bramer, Lisa M. [Pacific Northwest National Laboratory, Richland WA USA; Arntzen, Evan [Pacific Northwest National Laboratory, Richland WA USA; Romero, Elvira [Pacific Northwest National Laboratory, Richland WA USA; Resch, C. Tom [Pacific Northwest National Laboratory, Richland WA USA; Kennedy, David W. [Pacific Northwest National Laboratory, Richland WA USA; Stegen, James C. [Pacific Northwest National Laboratory, Richland WA USA

2017-12-01

In light of increasing terrestrial carbon (C) transport across aquatic boundaries, the mechanisms governing organic carbon (OC) oxidation along terrestrial-aquatic interfaces are crucial to future climate predictions. Here, we investigate biochemistry, metabolic pathways, and thermodynamics corresponding to OC oxidation in the Columbia River corridor. We leverage natural vegetative differences to encompass variation in terrestrial C inputs. Our results suggest that decreases in terrestrial C deposition associated with diminished riparian vegetation induce oxidation of physically-bound (i.e., mineral and microbial) OC at terrestrial-aquatic interfaces. We also find that contrasting metabolic pathways oxidize OC in the presence and absence of vegetation and—in direct conflict with the concept of ‘priming’—that inputs of water-soluble and thermodynamically-favorable terrestrial OC protects bound-OC from oxidation. Based on our results, we propose a mechanistic conceptualization of OC oxidation along terrestrial-aquatic interfaces that can be used to model heterogeneous patterns of OC loss under changing land cover distributions.

Error Bounds: Necessary and Sufficient Conditions

Czech Academy of Sciences Publication Activity Database

Outrata, Jiří; Kruger, A.Y.; Fabian, Marián; Henrion, R.

2010-01-01

Roč. 18, č. 2 (2010), s. 121-149 ISSN 1877-0533 R&D Projects: GA AV ČR IAA100750802 Institutional research plan: CEZ:AV0Z10750506; CEZ:AV0Z10190503 Keywords : Error bounds * Calmness * Subdifferential * Slope Subject RIV: BA - General Mathematics Impact factor: 0.333, year: 2010 http://library.utia.cas.cz/separaty/2010/MTR/outrata-error bounds necessary and sufficient conditions.pdf

Amos-type bounds for modified Bessel function ratios☆

Science.gov (United States)

Hornik, Kurt; Grün, Bettina

2013-01-01

We systematically investigate lower and upper bounds for the modified Bessel function ratio Rν=Iν+1/Iν by functions of the form Gα,β(t)=t/(α+t2+β2) in case Rν is positive for all t>0, or equivalently, where ν≥−1 or ν is a negative integer. For ν≥−1, we give an explicit description of the set of lower bounds and show that it has a greatest element. We also characterize the set of upper bounds and its minimal elements. If ν≥−1/2, the minimal elements are tangent to Rν in exactly one point 0≤t≤∞, and have Rν as their lower envelope. We also provide a new family of explicitly computable upper bounds. Finally, if ν is a negative integer, we explicitly describe the sets of lower and upper bounds, and give their greatest and least elements, respectively. PMID:24926105

Amos-type bounds for modified Bessel function ratios.

Science.gov (United States)

Hornik, Kurt; Grün, Bettina

2013-12-01

We systematically investigate lower and upper bounds for the modified Bessel function ratio [Formula: see text] by functions of the form [Formula: see text] in case [Formula: see text] is positive for all [Formula: see text], or equivalently, where [Formula: see text] or [Formula: see text] is a negative integer. For [Formula: see text], we give an explicit description of the set of lower bounds and show that it has a greatest element. We also characterize the set of upper bounds and its minimal elements. If [Formula: see text], the minimal elements are tangent to [Formula: see text] in exactly one point [Formula: see text], and have [Formula: see text] as their lower envelope. We also provide a new family of explicitly computable upper bounds. Finally, if [Formula: see text] is a negative integer, we explicitly describe the sets of lower and upper bounds, and give their greatest and least elements, respectively.

Energy conditions bounds and supernovae data

International Nuclear Information System (INIS)

Lima, M.P.; Vitenti, S.D.P.; Reboucas, M.J.

2008-01-01

The energy conditions play an important role in the description of some important properties of the Universe, including the current accelerating expansion phase and the possible recent phase of super-acceleration. In a recent work we have provided a detailed study of the energy conditions for the recent past by deriving bounds from energy conditions and by making the confrontation of the bounds with supernovae data. Here, we extend and update these results in two different ways. First, by carrying out a new statistical analysis for q(z) estimates needed for the confrontation between the bounds and supernovae data. Second, by providing a new picture of the energy conditions fulfillment and violation in the light of the recently compiled Union set of 307 type Ia supernovae and by using two different statistical approaches

Continuous bounded cohomology of locally compact groups

CERN Document Server

2001-01-01

Recent research has repeatedly led to connections between important rigidity questions and bounded cohomology. However, the latter has remained by and large intractable. This monograph introduces the functorial study of the continuous bounded cohomology for topological groups, with coefficients in Banach modules. The powerful techniques of this more general theory have successfully solved a number of the original problems in bounded cohomology. As applications, one obtains, in particular, rigidity results for actions on the circle, for representations on complex hyperbolic spaces and on Teichmüller spaces. A special effort has been made to provide detailed proofs or references in quite some generality.

Research on culture-bound syndromes: new directions.

Science.gov (United States)

Guarnaccia, P J; Rogler, L H

1999-09-01

The unprecedented inclusion of culture-bound syndromes in DSM-IV provides the opportunity for highlighting the need to study such syndromes and the occasion for developing a research agenda to study them. The growing ethnic and cultural diversity of the U.S. population presents a challenge to the mental health field to develop truly cross-cultural approaches to mental health research and services. In this article, the authors provide a critique of previous analyses of the relationship between culture-bound syndromes and psychiatric diagnoses. They highlight the problems in previous classificatory exercises, which tend to focus on subsuming the culture-bound syndromes into psychiatric categories and fail to fully investigate these syndromes on their own terms. A detailed research program based on four key questions is presented both to understand culture-bound syndromes within their cultural context and to analyze the relationship between these syndromes and psychiatric disorders. Results of over a decade of research on ataques de nervios, a Latino-Caribbean cultural syndrome, are used to illustrate this research program. The four questions focus on the nature of the phenomenon, the social-cultural location of sufferers, the relationship of culture-bound syndromes to psychiatric disorders, and the social and psychiatric history of the syndrome in the life course of the sufferer.

Class-specific Error Bounds for Ensemble Classifiers

Energy Technology Data Exchange (ETDEWEB)

Prenger, R; Lemmond, T; Varshney, K; Chen, B; Hanley, W

2009-10-06

The generalization error, or probability of misclassification, of ensemble classifiers has been shown to be bounded above by a function of the mean correlation between the constituent (i.e., base) classifiers and their average strength. This bound suggests that increasing the strength and/or decreasing the correlation of an ensemble's base classifiers may yield improved performance under the assumption of equal error costs. However, this and other existing bounds do not directly address application spaces in which error costs are inherently unequal. For applications involving binary classification, Receiver Operating Characteristic (ROC) curves, performance curves that explicitly trade off false alarms and missed detections, are often utilized to support decision making. To address performance optimization in this context, we have developed a lower bound for the entire ROC curve that can be expressed in terms of the class-specific strength and correlation of the base classifiers. We present empirical analyses demonstrating the efficacy of these bounds in predicting relative classifier performance. In addition, we specify performance regions of the ROC curve that are naturally delineated by the class-specific strengths of the base classifiers and show that each of these regions can be associated with a unique set of guidelines for performance optimization of binary classifiers within unequal error cost regimes.

Lower bounds on Q of some dipole shapes

DEFF Research Database (Denmark)

Kim, Oleksiy S.

2016-01-01

The lower bound on the radiation Q of an arbitrary electrically small antenna shape can be determined by finding the optimal electric current density on the exterior surface of the shape, such that the Q of this current radiating in free space is minimized, and then augmenting it with a magnetic...... current density cancelling the fields inside the shape's surface. The Q of these coupled electric and magnetic currents radiating in free space is the lower bound on Q for the given shape. The approach is exemplified and its general applicability is substantiated by computing the lower bounds...... of spherically capped dipoles and comparing the results to the known bounds of a sphere and a thin cylinder....

Cyclotron transitions of bound ions

Science.gov (United States)

Bezchastnov, Victor G.; Pavlov, George G.

2017-06-01

A charged particle in a magnetic field possesses discrete energy levels associated with particle rotation around the field lines. The radiative transitions between these levels are the well-known cyclotron transitions. We show that a bound complex of particles with a nonzero net charge displays analogous transitions between the states of confined motion of the entire complex in the field. The latter bound-ion cyclotron transitions are affected by a coupling between the collective and internal motions of the complex and, as a result, differ from the transitions of a "reference" bare ion with the same mass and charge. We analyze the cyclotron transitions for complex ions by including the coupling within a rigorous quantum approach. Particular attention is paid to comparison of the transition energies and oscillator strengths to those of the bare ion. Selection rules based on integrals of collective motion are derived for the bound-ion cyclotron transitions analytically, and the perturbation and coupled-channel approaches are developed to study the transitions quantitatively. Representative examples are considered and discussed for positive and negative atomic and cluster ions.

Bounded Rationality, Retaliation, and the Spread of Urban Violence

Science.gov (United States)

Jacobs, Bruce A.; Wright, Richard

2010-01-01

Drawing from in-depth interviews with 52 active street criminals, this article examines the grounded theoretic implications of bounded rationality for retaliatory street violence. The bounds on rationality that this article explores are anger, uncertainty, and time pressure. These bounds create imperfections in the retaliatory decision-making…

A Branch-and-Bound Algorithm Embedded with DCA for DC Programming

Directory of Open Access Journals (Sweden)

Meihua Wang

2012-01-01

Full Text Available The special importance of Difference of Convex (DC functions programming has been recognized in recent studies on nonconvex optimization problems. In this work, a class of DC programming derived from the portfolio selection problems is studied. The most popular method applied to solve the problem is the Branch-and-Bound (B&B algorithm. However, “the curse of dimensionality” will affect the performance of the B&B algorithm. DC Algorithm (DCA is an efficient method to get a local optimal solution. It has been applied to many practical problems, especially for large-scale problems. A B&B-DCA algorithm is proposed by embedding DCA into the B&B algorithms, the new algorithm improves the computational performance and obtains a global optimal solution. Computational results show that the proposed B&B-DCA algorithm has the superiority of the branch number and computational time than general B&B. The nice features of DCA (inexpensiveness, reliability, robustness, globality of computed solutions, etc. provide crucial support to the combined B&B-DCA for accelerating the convergence of B&B.

Alcohol dehydrogenase of acetic acid bacteria: structure, mode of action, and applications in biotechnology.

Science.gov (United States)

Yakushi, Toshiharu; Matsushita, Kazunobu

2010-05-01

Pyrroquinoline quinone-dependent alcohol dehydrogenase (PQQ-ADH) of acetic acid bacteria is a membrane-bound enzyme involved in the acetic acid fermentation by oxidizing ethanol to acetaldehyde coupling with reduction of membranous ubiquinone (Q), which is, in turn, re-oxidized by ubiquinol oxidase, reducing oxygen to water. PQQ-ADHs seem to have co-evolved with the organisms fitting to their own habitats. The enzyme consists of three subunits and has a pyrroloquinoline quinone, 4 heme c moieties, and a tightly bound Q as the electron transfer mediators. Biochemical, genetic, and electrochemical studies have revealed the unique properties of PQQ-ADH since it was purified in 1978. The enzyme is unique to have ubiquinol oxidation activity in addition to Q reduction. This mini-review focuses on the molecular properties of PQQ-ADH, such as the roles of the subunits and the cofactors, particularly in intramolecular electron transport of the enzyme from ethanol to Q. Also, we summarize biotechnological applications of PQQ-ADH as to enantiospecific oxidations for production of the valuable chemicals and bioelectrocatalysis for sensors and fuel cells using indirect and direct electron transfer technologies and discuss unsolved issues and future prospects related to this elaborate enzyme.

Bounds on the capacity of constrained two-dimensional codes

DEFF Research Database (Denmark)

Forchhammer, Søren; Justesen, Jørn

2000-01-01

Bounds on the capacity of constrained two-dimensional (2-D) codes are presented. The bounds of Calkin and Wilf apply to first-order symmetric constraints. The bounds are generalized in a weaker form to higher order and nonsymmetric constraints. Results are given for constraints specified by run-l...

Bound entangled states violate a nonsymmetric local uncertainty relation

International Nuclear Information System (INIS)

Hofmann, Holger F.

2003-01-01

As a consequence of having a positive partial transpose, bound entangled states lack many of the properties otherwise associated with entanglement. It is therefore interesting to identify properties that distinguish bound entangled states from separable states. In this paper, it is shown that some bound entangled states violate a nonsymmetric class of local uncertainty relations [H. F. Hofmann and S. Takeuchi, Phys. Rev. A 68, 032103 (2003)]. This result indicates that the asymmetry of nonclassical correlations may be a characteristic feature of bound entanglement

Lower Bounds to the Reliabilities of Factor Score Estimators.

Science.gov (United States)

Hessen, David J

2016-10-06

Under the general common factor model, the reliabilities of factor score estimators might be of more interest than the reliability of the total score (the unweighted sum of item scores). In this paper, lower bounds to the reliabilities of Thurstone's factor score estimators, Bartlett's factor score estimators, and McDonald's factor score estimators are derived and conditions are given under which these lower bounds are equal. The relative performance of the derived lower bounds is studied using classic example data sets. The results show that estimates of the lower bounds to the reliabilities of Thurstone's factor score estimators are greater than or equal to the estimates of the lower bounds to the reliabilities of Bartlett's and McDonald's factor score estimators.

Interactions between macromolecule-bound antioxidants and Trolox during liposome autoxidation

DEFF Research Database (Denmark)

Celik, Ecem Evrim; Amigo Rubio, Jose Manuel; Andersen, Mogens Larsen

2017-01-01

The interactions between free and macromolecule-bound antioxidants were investigated in order to evaluate their combined effects on the antioxidant environment. Dietary fiber (DF), protein and lipid-bound antioxidants, obtained from whole wheat, soybean and olive oil products, respectively and Tr...... of logistic function was successfully used for modelling the oxidation curve of liposomes. Principal component analysis revealed two separate phases of liposome autoxidation.......The interactions between free and macromolecule-bound antioxidants were investigated in order to evaluate their combined effects on the antioxidant environment. Dietary fiber (DF), protein and lipid-bound antioxidants, obtained from whole wheat, soybean and olive oil products, respectively...... of the simple addition effects of Trolox and bound antioxidants with measured values on lipid oxidation revealed synergetic interactions for DF and refined olive oil-bound antioxidants, and antagonistic interactions for protein and extra virgin olive oil-bound antioxidants with Trolox. A generalized version...

Computationally efficient analytic representations of relativistic bound-bound, bound-unbound and unbound-unbound transition matrix elements of hydrogenic atoms

International Nuclear Information System (INIS)

Soldatov, A.; Seke, J.; Adam, G.; Polak, M.

2008-01-01

Full text: A closed analytic form for relativistic transition matrix elements between bound-bound, bound-unbound and unbound-unbound relativistic eigenstates of hydrogenic atoms by using the plane-wave expansion for the electromagnetic-field vector potential was derived in a form convenient for large-scale numerical calculations in QED. By applying the obtained formulae, these transition matrix elements can be evaluated analytically and numerically. These exact matrix elements, which to our knowledge have not been calculated as yet, are of great importance in the analysis of various atom-field interaction processes where retardation effects cannot be ignored. The ultimate goal of the ongoing research is to develop a general universal calculation technique for Seke's approximation and renormalization method in QED, for which the usage of the plane vector expansion for the vector potential is a preferable choice. However, our primary interest lies in the Lamb-shift calculation. Our nearest objective is to carry out the plain-style relativistic calculations of the Lamb shift of the energy levels of hydrogen-like atoms and ions from first principles in the second and higher perturbative orders, using the corresponding convenient as well as novel expressions for the magnitude in question as they stand, i.e. without any additional approximations. Due to that there is no way to achieve all the above-declared goals without recourse to large-scale laborious and time-consuming high-precision numerical calculations, having the transition matrix elements of all possible types in an analytic, convenient for their efficient numerical evaluation form, would be highly advantageous and even unavoidable, especially for calculations of various QED effects in higher perturbative orders be it, equally, in traditional or novel approach. (author)

Dark-matter bound states from Feynman diagrams

NARCIS (Netherlands)

Petraki, K.; Postma, M.; Wiechers, M.

2015-01-01

If dark matter couples directly to a light force mediator, then it may form bound states in the early universe and in the non-relativistic environment of haloes today. In this work, we establish a field-theoretic framework for the computation of bound-state formation cross-sections, de-excitation

Circumvention of Parker's bound on galactic magnetic monopoles

International Nuclear Information System (INIS)

Dicus, D.A.; Teplitz, V.L.; Maryland Univ., College Park

1983-01-01

There is a possibility that a magnetic monopole has been observed. The monopole density implied by the observation appears to violate bounds on the density of such particles derived from the total mass density of the Universe and from the existence of galactic magnetic fields. It is shown that the observation is not inconsistent with these bounds if the monopoles and antimonopoles are bound into positronium like states with principal quantum n high enough so that the Earth's magnetic field will break them apart, but small enough so that the weaker galactic magnetic field will not. A range of values for n are determined and show that lifetimes for such bound states are longer than the current age of the Universe. (author)

Comparing two reliability upper bounds for multistate systems

International Nuclear Information System (INIS)

Meng, Fan C.

2005-01-01

The path-cut reliability bound due to Esary and Proschan [J. Am. Stat. Assoc. 65 (1970) 329] and the minimax reliability bound due to Barlow and Proschan [Statistical Theory of Reliability and Life Testing: Probability Models, 1981] for binary systems have been generalized to multistate systems by Block and Savits [J. Appl. Probab. 19 (1982) 391]. Some comparison results concerning the two multistate lower bounds for various types of multistate systems are given by Meng [Probab. Eng. Inform. Sci. 16 (2002) 485]. In this note we compare the two multistate upper bounds and present results which generalize some previous ones obtained by Maymin [J. Stat. Plan. Inference 16 (1987) 337] for binary systems. Examples are given to illustrate our results

Finite energy bounds for $\\piN$ scattering

CERN Document Server

Grassberger, P; Schwela, D

1974-01-01

Upper bounds on energy averaged pi N cross sections are given. Using low energy data and data from pi N backward scattering and NN to pi pi annihilation, it is found that sigma /sub tot/bounds are based on assumptions similar to those underlying Froissart's bound and are equal to it asymptotically. However, at finite but large energies, they increase much slower than what might have been anticipated on purely numerological grounds. Related problems in pp and Kp scattering are also discussed. (25 refs) .

Entropic Lower Bound for Distinguishability of Quantum States

Directory of Open Access Journals (Sweden)

Seungho Yang

2015-01-01

Full Text Available For a system randomly prepared in a number of quantum states, we present a lower bound for the distinguishability of the quantum states, that is, the success probability of determining the states in the form of entropy. When the states are all pure, acquiring the entropic lower bound requires only the density operator and the number of the possible states. This entropic bound shows a relation between the von Neumann entropy and the distinguishability.

Entropy Bounds for Constrained Two-Dimensional Fields

DEFF Research Database (Denmark)

Forchhammer, Søren Otto; Justesen, Jørn

1999-01-01

The maximum entropy and thereby the capacity of 2-D fields given by certain constraints on configurations are considered. Upper and lower bounds are derived.......The maximum entropy and thereby the capacity of 2-D fields given by certain constraints on configurations are considered. Upper and lower bounds are derived....

Resistance of soil-bound prions to rumen digestion.

Directory of Open Access Journals (Sweden)

Samuel E Saunders

Full Text Available Before prion uptake and infection can occur in the lower gastrointestinal system, ingested prions are subjected to anaerobic digestion in the rumen of cervids and bovids. The susceptibility of soil-bound prions to rumen digestion has not been evaluated previously. In this study, prions from infectious brain homogenates as well as prions bound to a range of soils and soil minerals were subjected to in vitro rumen digestion, and changes in PrP levels were measured via western blot. Binding to clay appeared to protect noninfectious hamster PrP(c from complete digestion, while both unbound and soil-bound infectious PrP(Sc proved highly resistant to rumen digestion. In addition, no change in intracerebral incubation period was observed following active rumen digestion of unbound hamster HY TME prions and HY TME prions bound to a silty clay loam soil. These results demonstrate that both unbound and soil-bound prions readily survive rumen digestion without a reduction in infectivity, further supporting the potential for soil-mediated transmission of chronic wasting disease (CWD and scrapie in the environment.

Resistance of Soil-Bound Prions to Rumen Digestion

Science.gov (United States)

Saunders, Samuel E.; Bartelt-Hunt, Shannon L.; Bartz, Jason C.

2012-01-01

Before prion uptake and infection can occur in the lower gastrointestinal system, ingested prions are subjected to anaerobic digestion in the rumen of cervids and bovids. The susceptibility of soil-bound prions to rumen digestion has not been evaluated previously. In this study, prions from infectious brain homogenates as well as prions bound to a range of soils and soil minerals were subjected to in vitro rumen digestion, and changes in PrP levels were measured via western blot. Binding to clay appeared to protect noninfectious hamster PrPc from complete digestion, while both unbound and soil-bound infectious PrPSc proved highly resistant to rumen digestion. In addition, no change in intracerebral incubation period was observed following active rumen digestion of unbound hamster HY TME prions and HY TME prions bound to a silty clay loam soil. These results demonstrate that both unbound and soil-bound prions readily survive rumen digestion without a reduction in infectivity, further supporting the potential for soil-mediated transmission of chronic wasting disease (CWD) and scrapie in the environment. PMID:22937149

Lying for the Greater Good: Bounded Rationality in a Team

Directory of Open Access Journals (Sweden)

Oktay Sürücü

2014-10-01

Full Text Available This paper is concerned with the interaction between fully and boundedly rational agents in situations where their interests are perfectly aligned. The cognitive limitations of the boundedly rational agent do not allow him to fully understand the market conditions and lead him to take non-optimal decisions in some situations. Using categorization to model bounded rationality, we show that the fully rational agent can nudge, i.e., he can manipulate the information he sends and decrease the expected loss caused by the boundedly rational agent. Assuming different types for the boundedly rational agent, who differ only in the categories used, we show that the fully rational agent may learn the type of the boundedly rational agent along their interaction. Using this additional information, the outcome can be improved and the amount of manipulated information can be decreased. Furthermore, as the length of the interaction increases the probability that the fully rational agent learns the type of the boundedly rational agent grows

H32, a non-quinone sulfone analog of vitamin K3, inhibits human hepatoma cell growth by inhibiting Cdc25 and activating ERK.

Science.gov (United States)

Kar, Siddhartha; Wang, Meifang; Ham, Seung Wook; Carr, Brian I

2006-10-01

We previously synthesized a K-vitamin derivative, Cpd 5, which was a potent growth inhibitor of human tumor cells, including Hep3B hepatoma cells. However, being a quinone compound, Cpd 5 has the potential for generating toxic reactive oxygen species (ROS). We therefore synthesized a nonquinone sulfone derivative, H32, which has a sufone group substituting the quinone. The IC50 of H32 for Hep3B cells was found to be 2.5 microM, which was 2.5 and 3.2 times more potent than Cpd 5 and vitamin K3 respectively. It induced apoptosis in Hep3B cells but did not generate ROS when compared to Cpd 5. Interestingly, under similar culture conditions, normal rat hepatocytes were 14-fold more and 7-fold more resistant to the growth inhibitory effects of H32 than Hep3B and PLC/PRF5 cells respectively. H32 preferentially inhibited the activities of the cell cycle controlling Cdc25A phosphatase likely by binding to its catalytic cysteine. As a consequence, it induced inhibitory tyrosine phosphorylation of the Cdc25 substrate kinases Cdk2 and Cdk4 in Hep3B cells and the cells undergo an arrest in the G1 phase of the cell cycle. H32 also induced persistent phosphorylation of the MAPK protein ERK1/2, but marginal JNK1/2 and p38 phosphorylation. The ERK inhibitor U0126, added at least 30 min prior to H32, antagonized the growth inhibition induced by H32. However, the JNK and p38 inhibitors, JNKI-II and SB203580, were not able to antagonize H32 induced growth inhibition. Thus, H32 differentially inhibited growth of normal and liver tumor cells by preferentially inhibiting the actions of Cdc25 phosphatases and inducing persistent ERK phosphorylation.

Role of Quinone Reductase 2 in the Antimalarial Properties of Indolone-Type Derivatives

Directory of Open Access Journals (Sweden)

Laure-Estelle Cassagnes

2017-01-01

Full Text Available Indolone-N-oxides have antiplasmodial properties against Plasmodium falciparum at the erythrocytic stage, with IC50 values in the nanomolar range. The mechanism of action of indolone derivatives involves the production of free radicals, which follows their bioreduction by an unknown mechanism. In this study, we hypothesized that human quinone reductase 2 (hQR2, known to act as a flavin redox switch upon binding to the broadly used antimalarial chloroquine, could be involved in the activity of the redox-active indolone derivatives. Therefore, we investigated the role of hQR2 in the reduction of indolone derivatives. We analyzed the interaction between hQR2 and several indolone-type derivatives by examining enzymatic kinetics, the substrate/protein complex structure with X-ray diffraction analysis, and the production of free radicals with electron paramagnetic resonance. The reduction of each compound in cells overexpressing hQR2 was compared to its reduction in naïve cells. This process could be inhibited by the specific hQR2 inhibitor, S29434. These results confirmed that the anti-malarial activity of indolone-type derivatives was linked to their ability to serve as hQR2 substrates and not as hQR2 inhibitors as reported for chloroquine, leading to the possibility that substrate of hQR2 could be considered as a new avenue for the design of new antimalarial compounds.

Bounded dust-acoustic waves in a cylindrically bounded collisional dusty plasma with dust charge variation

International Nuclear Information System (INIS)

Wei Nanxia; Xue Jukui

2006-01-01

Taking into account the boundary, particle collisions, and dust charging effects, dust-acoustic waves in a uniform cylindrically bounded dusty plasma is investigated analytically, and the dispersion relation for the dust-acoustic wave is obtained. The effects of boundary, dust charge variation, particle collision, and dust size on the dust-acoustic wave are discussed in detail. Due to the bounded cylindrical boundary effects, the radial wave number is discrete, i.e., the spectrum is discrete. It is shown that the discrete spectrum, the adiabatic dust charge variation, dust grain size, and the particle collision have significant effects on the dust-acoustic wave

Casein kinase II protein kinase is bound to lamina-matrix and phosphorylates lamin-like protein in isolated pea nuclei

Science.gov (United States)

Li, H.; Roux, S. J.

1992-01-01

A casein kinase II (CK II)-like protein kinase was identified and partially isolated from a purified envelope-matrix fraction of pea (Pisum sativum L.) nuclei. When [gamma-32P]ATP was directly added to the envelope-matrix preparation, the three most heavily labeled protein bands had molecular masses near 71, 48, and 46 kDa. Protein kinases were removed from the preparation by sequential extraction with Triton X-100, EGTA, 0.3 M NaCl, and a pH 10.5 buffer, but an active kinase still remained bound to the remaining lamina-matrix fraction after these treatments. This kinase had properties resembling CK II kinases previously characterized from animal and plant sources: it preferred casein as an artificial substrate, could use GTP as efficiently as ATP as the phosphoryl donor, was stimulated by spermine, was calcium independent, and had a catalytic subunit of 36 kDa. Some animal and plant CK II kinases have regulatory subunits near 29 kDa, and a lamina-matrix-bound protein of this molecular mass was recognized on immunoblot by anti-Drosophila CK II polyclonal antibodies. Also found associated with the envelope-matrix fraction of pea nuclei were p34cdc2-like and Ca(2+)-dependent protein kinases, but their properties could not account for the protein kinase activity bound to the lamina. The 71-kDa substrate of the CK II-like kinase was lamin A-like, both in its molecular mass and in its cross-reactivity with anti-intermediate filament antibodies. Lamin phosphorylation is considered a crucial early step in the entry of cells into mitosis, so lamina-bound CK II kinases may be important control points for cellular proliferation.

Chloroplast protein synthesis: thylakoid bound polysomes synthesize thylakoid proteins

International Nuclear Information System (INIS)

Hurewitz, J.; Jagendorf, A.T.

1986-01-01

Previous work indicated more polysomes bound to pea thylakoids in light than in the dark, in vivo. With isolated intact chloroplasts incubated in darkness, 24 to 74% more RNA was thylakoid-bound at pH 8.3 than at pH 7. Thus the major effect of light in vivo may be due to higher stroma pH. In isolated pea chloroplasts, initiation inhibitors (pactamycin and kanamycin) decreased the extent of RNA binding, and elongation inhibitors (lincomycin and streptomycin) increased it. Thus translation initiation and termination probably control the cycling of bound ribosomes. While only 3 to 6% of total RNA is in bound polysomes the incorporation of 3 H-Leu into thylakoids was proportional to the amount of this bound RNA. When Micrococcal nuclease-treated thylakoids were added to labeled runoff translation products of stroma ribosomes, less than 1% of the label adhered to the added membranes; but 37% of the labeled products made by thylakoid polysomes were bound. These data support the concept that stroma ribosomes are recruited into thylakoid proteins

A dual Lewis base activation strategy for enantioselective carbene-catalyzed annulations.

Science.gov (United States)

Izquierdo, Javier; Orue, Ane; Scheidt, Karl A

2013-07-24

A dual activation strategy integrating N-heterocyclic carbene (NHC) catalysis and a second Lewis base has been developed. NHC-bound homoenolate equivalents derived from α,β-unsaturated aldehydes combine with transient reactive o-quinone methides in an enantioselective formal [4 + 3] fashion to access 2-benzoxopinones. The overall approach provides a general blueprint for the integration of carbene catalysis with additional Lewis base activation modes.

An upper-bound assessment of the benefits of reducing perchlorate in drinking water.

Science.gov (United States)

Lutter, Randall

2014-10-01

The Environmental Protection Agency plans to issue new federal regulations to limit drinking water concentrations of perchlorate, which occurs naturally and results from the combustion of rocket fuel. This article presents an upper-bound estimate of the potential benefits of alternative maximum contaminant levels for perchlorate in drinking water. The results suggest that the economic benefits of reducing perchlorate concentrations in drinking water are likely to be low, i.e., under $2.9 million per year nationally, for several reasons. First, the prevalence of detectable perchlorate in public drinking water systems is low. Second, the population especially sensitive to effects of perchlorate, pregnant women who are moderately iodide deficient, represents a minority of all pregnant women. Third, and perhaps most importantly, reducing exposure to perchlorate in drinking water is a relatively ineffective way of increasing iodide uptake, a crucial step linking perchlorate to health effects of concern. © 2014 Society for Risk Analysis.

Reducing Conservatism of Analytic Transient Response Bounds via Shaping Filters

Science.gov (United States)

Kwan, Aiyueh; Bedrossian, Nazareth; Jan, Jiann-Woei; Grigoriadis, Karolos; Hua, Tuyen (Technical Monitor)

1999-01-01

Recent results show that the peak transient response of a linear system to bounded energy inputs can be computed using the energy-to-peak gain of the system. However, analytically computed peak response bound can be conservative for a class of class bounded energy signals, specifically pulse trains generated from jet firings encountered in space vehicles. In this paper, shaping filters are proposed as a Methodology to reduce the conservatism of peak response analytic bounds. This Methodology was applied to a realistic Space Station assembly operation subject to jet firings. The results indicate that shaping filters indeed reduce the predicted peak response bounds.

A proactive and holistic information management approach is crucial ...

African Journals Online (AJOL)

ESARBICA Journal: Journal of the Eastern and Southern Africa Regional Branch of ... holistic information management approach is crucial to e-government development ... and to develop new electronic services hence boosting innovation.

Calculations of antiproton-nucleus quasi-bound states using the Paris N bar N potential

Science.gov (United States)

Hrtánková, Jaroslava; Mareš, Jiří

2018-01-01

An optical potential constructed using the p bar N scattering amplitudes derived from the 2009 version of the Paris N bar N potential is applied in calculations of p bar quasi-bound states in selected nuclei across the periodic table. A proper self-consistent procedure for treating energy dependence of the amplitudes in a nucleus appears crucial for evaluating p bar binding energies and widths. Particular attention is paid to the role of P-wave amplitudes. While the P-wave potential nearly does not affect calculated p bar binding energies, it reduces considerably the corresponding widths. The Paris S-wave potential supplemented by a phenomenological P-wave term yields in dynamical calculations p bar binding energies Bpbar ≈ 200 MeV and widths Γpbar ∼ 200- 230 MeV, which is very close to the values obtained within the RMF model consistent with p bar -atom data.

On the range of completely bounded maps

Directory of Open Access Journals (Sweden)

Richard I. Loebl

1978-01-01

Full Text Available It is shown that if every bounded linear map from a C*-algebra α to a von Neumann algebra β is completely bounded, then either α is finite-dimensional or β⫅⊗Mn, where is a commutative von Neumann algebra and Mn is the algebra of n×n complex matrices.

Experimental evidence for bounds on quantum correlations.

Science.gov (United States)

Bovino, F A; Castagnoli, G; Degiovanni, I P; Castelletto, S

2004-02-13

We implemented the experiment proposed by Cabello in the preceding Letter to test the bounds of quantum correlation. As expected from the theory we found that, for certain choices of local observables, Tsirelson's bound of the Clauser-Horne-Shimony-Holt inequality (2 x square root of 2) is not reached by any quantum states.

Bound water in Kevlar 49 fibers

International Nuclear Information System (INIS)

Garza, R.G.; Pruneda, C.O.; Morgan, R.J.

1981-01-01

From elemental analyses, thermogravimetric-mass spectroscopy studies and re-evaluation of previous water diffusion studies in Kevlar 49 fibers it is concluded that these fibers can contain two types of sorbed moisture. The fibers can absorb up to approx. 6 wt % loosely bound water with an activation energy for outgassing by desorption of 6 kcal/mole. This loosely bound water is a direct result of the presence of Na 2 SO 4 impurities and the perturbations they induce on the packing of the rod-like poly (p-phenylene terephthalamide) macromolecules. Kevlar 49 fibers also inherently contain up to 30 wt % additional water which is tightly bound within the crystal lattice. This water exhibits an activation energy for outgassing by diffusion of approx. 40 kcal/mole and is only evolved from the fiber in significant quantities at t > 350 0 C over a period of hours

On the Applicability of Lower Bounds for Solving Rectilinear

DEFF Research Database (Denmark)

Clausen, Jens; Karisch, Stefan E.; Perregaard, M.

1998-01-01

. Recently, lower bounds based on decomposition were proposed for the so called rectilinear QAP that proved to be the strongest for a large class of problem instances. We investigate the strength of these bounds when applied not only at the root node of a search tree but as the bound function used......The quadratic assignment problem (QAP) belongs to the hard core of NP-hard optimization problems. After almost forty years of research only relatively small instances can be solved to optimality. The reason is that the quality of the lower bounds available for exact methods is not sufficient...

Upper bounds on quantum uncertainty products and complexity measures

Energy Technology Data Exchange (ETDEWEB)

Guerrero, Angel; Sanchez-Moreno, Pablo; Dehesa, Jesus S. [Department of Atomic, Molecular and Nuclear Physics, University of Granada, Granada (Spain); Department of Applied Mathematics, University of Granada, Granada (Spain) and Institute Carlos I for Computational and Theoretical Physics, University of Granada, Granada (Spain); Department of Atomic, Molecular and Nuclear Physics, University of Granada, Granada (Spain); Institute Carlos I for Computational and Theoretical Physics, University of Granada, Granada (Spain)

2011-10-15

The position-momentum Shannon and Renyi uncertainty products of general quantum systems are shown to be bounded not only from below (through the known uncertainty relations), but also from above in terms of the Heisenberg-Kennard product . Moreover, the Cramer-Rao, Fisher-Shannon, and Lopez-Ruiz, Mancini, and Calbet shape measures of complexity (whose lower bounds have been recently found) are also bounded from above. The improvement of these bounds for systems subject to spherically symmetric potentials is also explicitly given. Finally, applications to hydrogenic and oscillator-like systems are done.

Bounded Perturbation Regularization for Linear Least Squares Estimation

KAUST Repository

Ballal, Tarig; Suliman, Mohamed Abdalla Elhag; Al-Naffouri, Tareq Y.

2017-01-01

This paper addresses the problem of selecting the regularization parameter for linear least-squares estimation. We propose a new technique called bounded perturbation regularization (BPR). In the proposed BPR method, a perturbation with a bounded

Lower bounds on scintillation detector timing performance

International Nuclear Information System (INIS)

Clinthorne, N.H.; Rogers, W.L.; Hero, A.O. III.; Petrick, N.A.

1990-01-01

Fundamental method-independent limits on the timing performance of scintillation detectors are useful for identifying regimes in which either present timing methods are nearly optimal or where a considerable performance gain might be realized using better pulse processing techniques. Several types of lower bounds on mean-squared timing error (MSE) performance have been developed and applied to scintillation detectors. The simple Cramer-Rao (CR) bound can be useful in determining the limiting MSE for scintillators having a relatively high rate of photon problction such as BaF 2 and NaI(Tl); however, it tends to overestimate the achievalbe performance for scintillators with lower rates such as BGO. For this reason, alternative bounds have been developed using rate-distortion theory or by assuming that the conversion of energy to scintillation light must pass through excited states which have exponential lifetime densities. The bounds are functions of the mean scintillation pulse shape, the scintillation intensity, and photodetector characteristics; they are simple to evaluate and can be used to conveniently assess the limiting timing performance of scintillation detectors. (orig.)

The pea SAD short-chain dehydrogenase/reductase: quinone reduction, tissue distribution, and heterologous expression.

Science.gov (United States)

Scherbak, Nikolai; Ala-Häivälä, Anneli; Brosché, Mikael; Böwer, Nathalie; Strid, Hilja; Gittins, John R; Grahn, Elin; Eriksson, Leif A; Strid, Åke

2011-04-01

The pea (Pisum sativum) tetrameric short-chain alcohol dehydrogenase-like protein (SAD) family consists of at least three highly similar members (SAD-A, -B, and -C). According to mRNA data, environmental stimuli induce SAD expression. The aim of this study was to characterize the SAD proteins by examining their catalytic function, distribution in pea, and induction in different tissues. In enzyme activity assays using a range of potential substrates, the SAD-C enzyme was shown to reduce one- or two-ring-membered quinones lacking long hydrophobic hydrocarbon tails. Immunological assays using a specific antiserum against the protein demonstrated that different tissues and cell types contain small amounts of SAD protein that was predominantly located within epidermal or subepidermal cells and around vascular tissue. Particularly high local concentrations were observed in the protoderm of the seed cotyledonary axis. Two bow-shaped rows of cells in the ovary and the placental surface facing the ovule also exhibited considerable SAD staining. Ultraviolet-B irradiation led to increased staining in epidermal and subepidermal cells of leaves and stems. The different localization patterns of SAD suggest functions both in development and in responses to environmental stimuli. Finally, the pea SAD-C promoter was shown to confer heterologous wound-induced expression in Arabidopsis (Arabidopsis thaliana), which confirmed that the inducibility of its expression is regulated at the transcriptional level.

Cosmological implications of Dark Matter bound states

Energy Technology Data Exchange (ETDEWEB)

Mitridate, Andrea [Scuola Normale Superiore, Piazza dei Cavalieri 7, 56126, Pisa (Italy); Redi, Michele; Smirnov, Juri [INFN, Sezione di Firenze, and Dipartimento di Fisica e Astronomia, Università di Firenze, Via G. Sansone 1, 50019 Sesto Fiorentino (Italy); Strumia, Alessandro, E-mail: andrea.mitridate@gmail.com, E-mail: michele.redi@fi.infn.it, E-mail: juri.smirnov@mpi-hd.mpg.de, E-mail: alessandro.strumia@cern.ch [Dipartimento di Fisica dell' Università di Pisa and INFN, Pisa (Italy)

2017-05-01

We present generic formulæ for computing how Sommerfeld corrections together with bound-state formation affects the thermal abundance of Dark Matter with non-abelian gauge interactions. We consider DM as a fermion 3plet (wino) or 5plet under SU(2) {sub L} . In the latter case bound states raise to 11.5 TeV the DM mass required to reproduce the cosmological DM abundance and give indirect detection signals such as (for this mass) a dominant γ-line around 70 GeV. Furthermore, we consider DM co-annihilating with a colored particle, such as a squark or a gluino, finding that bound state effects are especially relevant in the latter case.

Fast concurrent array-based stacks, queues and deques using fetch-and-increment-bounded, fetch-and-decrement-bounded and store-on-twin synchronization primitives

Science.gov (United States)

Chen, Dong; Gara, Alana; Heidelberger, Philip; Kumar, Sameer; Ohmacht, Martin; Steinmacher-Burow, Burkhard; Wisniewski, Robert

2014-09-16

Implementation primitives for concurrent array-based stacks, queues, double-ended queues (deques) and wrapped deques are provided. In one aspect, each element of the stack, queue, deque or wrapped deque data structure has its own ticket lock, allowing multiple threads to concurrently use multiple elements of the data structure and thus achieving high performance. In another aspect, new synchronization primitives FetchAndIncrementBounded (Counter, Bound) and FetchAndDecrementBounded (Counter, Bound) are implemented. These primitives can be implemented in hardware and thus promise a very fast throughput for queues, stacks and double-ended queues.

Cosmological stability bound in massive gravity and bigravity

International Nuclear Information System (INIS)

Fasiello, Matteo; Tolley, Andrew J.

2013-01-01

We give a simple derivation of a cosmological bound on the graviton mass for spatially flat FRW solutions in massive gravity with an FRW reference metric and for bigravity theories. This bound comes from the requirement that the kinetic term of the helicity zero mode of the graviton is positive definite. The bound is dependent only on the parameters in the massive gravity potential and the Hubble expansion rate for the two metrics. We derive the decoupling limit of bigravity and FRW massive gravity, and use this to give an independent derivation of the cosmological bound. We recover our previous results that the tension between satisfying the Friedmann equation and the cosmological bound is sufficient to rule out all observationally relevant FRW solutions for massive gravity with an FRW reference metric. In contrast, in bigravity this tension is resolved due to different nature of the Vainshtein mechanism. We find that in bigravity theories there exists an FRW solution with late-time self-acceleration for which the kinetic terms for the helicity-2, helicity-1 and helicity-0 are generically nonzero and positive making this a compelling candidate for a model of cosmic acceleration. We confirm that the generalized bound is saturated for the candidate partially massless (bi)gravity theories but the existence of helicity-1/helicity-0 interactions implies the absence of the conjectured partially massless symmetry for both massive gravity and bigravity

On Landauer's Principle and Bound for Infinite Systems

Science.gov (United States)

Longo, Roberto

2018-04-01

Landauer's principle provides a link between Shannon's information entropy and Clausius' thermodynamical entropy. Here we set up a basic formula for the incremental free energy of a quantum channel, possibly relative to infinite systems, naturally arising by an Operator Algebraic point of view. By the Tomita-Takesaki modular theory, we can indeed describe a canonical evolution associated with a quantum channel state transfer. Such evolution is implemented both by a modular Hamiltonian and a physical Hamiltonian, the latter being determined by its functoriality properties. This allows us to make an intrinsic analysis, extending our QFT index formula, but without any a priori given dynamics; the associated incremental free energy is related to the logarithm of the Jones index and is thus quantised. This leads to a general lower bound for the incremental free energy of an irreversible quantum channel which is half of the Landauer bound, and to further bounds corresponding to the discrete series of the Jones index. In the finite dimensional context, or in the case of DHR charges in QFT, where the dimension is a positive integer, our lower bound agrees with Landauer's bound.

Microscopic observation of magnon bound states and their dynamics.

Science.gov (United States)

Fukuhara, Takeshi; Schauß, Peter; Endres, Manuel; Hild, Sebastian; Cheneau, Marc; Bloch, Immanuel; Gross, Christian

2013-10-03

The existence of bound states of elementary spin waves (magnons) in one-dimensional quantum magnets was predicted almost 80 years ago. Identifying signatures of magnon bound states has so far remained the subject of intense theoretical research, and their detection has proved challenging for experiments. Ultracold atoms offer an ideal setting in which to find such bound states by tracking the spin dynamics with single-spin and single-site resolution following a local excitation. Here we use in situ correlation measurements to observe two-magnon bound states directly in a one-dimensional Heisenberg spin chain comprising ultracold bosonic atoms in an optical lattice. We observe the quantum dynamics of free and bound magnon states through time-resolved measurements of two spin impurities. The increased effective mass of the compound magnon state results in slower spin dynamics as compared to single-magnon excitations. We also determine the decay time of bound magnons, which is probably limited by scattering on thermal fluctuations in the system. Our results provide a new way of studying fundamental properties of quantum magnets and, more generally, properties of interacting impurities in quantum many-body systems.

Bounds and estimates for the linearly perturbed eigenvalue problem

International Nuclear Information System (INIS)

Raddatz, W.D.

1983-01-01

This thesis considers the problem of bounding and estimating the discrete portion of the spectrum of a linearly perturbed self-adjoint operator, M(x). It is supposed that one knows an incomplete set of data consisting in the first few coefficients of the Taylor series expansions of one or more of the eigenvalues of M(x) about x = 0. The foundations of the variational study of eigen-values are first presented. These are then used to construct the best possible upper bounds and estimates using various sets of given information. Lower bounds are obtained by estimating the error in the upper bounds. The extension of these bounds and estimates to the eigenvalues of the doubly-perturbed operator M(x,y) is discussed. The results presented have numerous practical application in the physical sciences, including problems in atomic physics and the theory of vibrations of acoustical and mechanical systems

Bounds on the pomeron intercept from accelerator data

International Nuclear Information System (INIS)

Luna, E.G.S.; Menon, M.J.

2002-01-01

Taking into account the discrepancies in the pp and p-bar p total cross section data at √8 = 1.8 TeV, we estimate upper and lower bounds for the soft pomeron intercept. We make use of the Donnachie-Landshoff parameterization for the total cross section and derivative analyticity relations in order to calculate the ρ parameter. Individual and global fits to these quantities and tests with the subtraction constant allow to infer α IP (0) = 1.092 as upper bound and α IP (0) = 1.077 as lower bound. (author)

Charged boson bound states in the kerr-newman metric

International Nuclear Information System (INIS)

Li Yuanjie; Zhang Duanming

1986-01-01

Charged boson bound states in Kerr-Newman metric are discussed. It is found that massless boson cannot be attracted by Kerr-Newman black hole to form bound states. For the massive boson, the condition of the nonbound states when 0 2 - Q 2 and both the condition and wave functions of the bound states when a = √M 2 - Q 2 are obtained. The energy mode of the bound states is single, E = (m√M 2 - Q 2 + eQM)/(2M 2 - Q 2 ). When Q = 0 or e = 0, the conclusion is in agreement with that of Zhang Shiwei and Su Rukeng

Analysis of the organically bound tritium

International Nuclear Information System (INIS)

Baglan, N.; Alanic, G.

2011-01-01

In environmental samples, tritium is very often combined with the fraction of bulk water accumulated in the sample but also in the form of organically bound tritium. When the tritium is organically bound, 2 forms can coexist: the exchangeable fraction and the non-exchangeable fraction. The analysis of the different forms of tritium present in the sample is necessary to assess the sanitary hazards due to tritium. The total tritium is obtained from the analysis of the water released when the fresh sample is burnt while the organically bound tritium is obtained from the analysis of the water released when the dry extract of the sample is burnt. The measurement of the exchangeable fraction and the non-exchangeable fraction requires an additional stage of labile exchange. The exchangeable fraction is determined from the analysis of the water released during the labile exchange and the non-exchangeable fraction is determined from the water released during the combustion of the dry extract of the labile exchange

Search for quasi bound η mesons

International Nuclear Information System (INIS)

Machner, H

2015-01-01

The search for a quasi bound η meson in atomic nuclei is reviewed. This tentative state is studied theoretically as well as experimentally. The theory starts from elastic η nucleon scattering which is derived from production data within some models. From this interaction the η nucleus interaction is derived. Model calculations predict binding energies and widths of the quasi bound state. Another method is to derive the η nucleus interaction from excitation functions of η production experiments. The s wave interaction is extracted from such data via final state interaction (FSI) theorem. We give the derivation of s wave amplitudes in partial wave expansion and in helicity amplitudes and their relation to observables. Different experiments extracting the FSI are discussed as are production experiments. So far only three experiments give evidence for the existence of the quasi bound state: a pion double charge exchange experiment, an effective mass measurement, and a transfer reaction at recoil free kinematics with observation of the decay of the state. (topical review)

Adaptation dans les zones cruciales au regard des changements ...

International Development Research Centre (IDRC) Digital Library (Canada)

) vise à accroître la résilience des populations pauvres dans trois « zones cruciales » au regard des changements climatiques : les bassins hydrographiques, les deltas et les régions semi-arides.

On an extension of the space of bounded deformations

Czech Academy of Sciences Publication Activity Database

Kružík, Martin; Zimmer, J.

2012-01-01

Roč. 31, č. 1 (2012), s. 75-91 ISSN 0232-2064 R&D Projects: GA AV ČR IAA100750802 Institutional research plan: CEZ:AV0Z10750506 Keywords : Bounded sequences of symmetrised gradients * bounded deformation Subject RIV: BA - General Mathematics Impact factor: 0.620, year: 2012 http://library.utia.cas.cz/separaty/2012/MTR/kruzik-on an extension of the space of bounded deformations.pdf

Testing and using the Lewin-Lieb bounds in density functional theory

Science.gov (United States)

Feinblum, David; Kenison, John; Burke, Kieron

Lewin and Lieb have recently proven several new bounds on the exchange-correlation energy that complement the Lieb-Oxford bound. We test these bounds for atoms, for slowly-varying gases, and for Hooke's atom, finding them usually less strict than the Lieb-Oxford bound. However, we also show that, if a generalized gradient approximation (GGA) is to guarantee satisfaction of the new bounds for all densities, new restrictions on the the exchange-correlation enhancement factor are implied. We thank Mathieu Lewin and Elliott Lieb for bringing their new bounds to our attention, and Eberhard Engel for developing the OPMKS atom code. This work was supported by NSF under Grant CHE-1112442.

The linear programming bound for binary linear codes

NARCIS (Netherlands)

Brouwer, A.E.

1993-01-01

Combining Delsarte's (1973) linear programming bound with the information that certain weights cannot occur, new upper bounds for dmin (n,k), the maximum possible minimum distance of a binary linear code with given word length n and dimension k, are derived.

Can the Σ-nn system be bound?

International Nuclear Information System (INIS)

Stadler, A.; Gibson, B.F.

1994-01-01

Motivated by the Σ-hypernuclear states reported in (K - ,π ± ) experiments, we have explored the possibility that there exists a particle-stable Σ - nn bound state. For the Juelich A hyperon-nucleon, realistic-force model, our calculations yield little reason to expect a positive-parity bound state or resonance in either the J=1/2 or the J=3/2 channels

Bounded Gaps between Products of Special Primes

Directory of Open Access Journals (Sweden)

Ping Ngai Chung

2014-03-01

Full Text Available In their breakthrough paper in 2006, Goldston, Graham, Pintz and Yıldırım proved several results about bounded gaps between products of two distinct primes. Frank Thorne expanded on this result, proving bounded gaps in the set of square-free numbers with r prime factors for any r ≥ 2, all of which are in a given set of primes. His results yield applications to the divisibility of class numbers and the triviality of ranks of elliptic curves. In this paper, we relax the condition on the number of prime factors and prove an analogous result using a modified approach. We then revisit Thorne’s applications and give a better bound in each case.

Yukawa Bound States and Their LHC Phenomenology

Directory of Open Access Journals (Sweden)

Enkhbat Tsedenbaljir

2013-01-01

Full Text Available We present the current status on the possible bound states of extra generation quarks. These include phenomenology and search strategy at the LHC. If chiral fourth-generation quarks do exist their strong Yukawa couplings, implied by current experimental lower bound on their masses, may lead to formation of bound states. Due to nearly degenerate 4G masses suggested by Precision Electroweak Test one can employ “heavy isospin” symmetry to classify possible spectrum. Among these states, the color-octet isosinglet vector ω 8 is the easiest to be produced at the LHC. The discovery potential and corresponding decay channels are covered in this paper. With possible light Higgs at ~125 GeV two-Higgs doublet version is briefly discussed.

Thermodynamic Upper Bound on Broadband Light Coupling with Photonic Structures

KAUST Repository

Yu, Zongfu; Raman, Aaswath; Fan, Shanhui

2012-01-01

to an upper bound dictated by the second law of thermodynamics. Such bound limits how efficient light can be coupled to any photonic structure. As one example of application, we use this upper bound to derive the limit of light absorption in broadband solar

Spectrofluorimetric determination of gemifloxacin mesylate and linezolid in pharmaceutical formulations: Application of quinone-based fluorophores and enhanced native fluorescence

Directory of Open Access Journals (Sweden)

Moussa Bahia Abbas

2014-03-01

Full Text Available Quinone-based fluorophores and enhanced native fluorescence techniques were applied for a fast quantitative analysis of gemifloxacin mesylate (GEM and linezolid (LIN in pharmaceutical formulations. For this purpose, three sensitive, accurate and precise spectrofluorimetric methods were developed. GEM, as an n-electron donor, reacts with 7,7,8,8-tetracyanoquinodimethane (method A and 2,5-dichloro-3,6-dihydroxy-p-benzoquinone (method B as п-electron acceptors, forming charge transfer complexes that exhibit high fluorescence intensity at 441 and 390 nm upon excitation at 260 and 339 nm, respectively. Method C depends on measurement of enhanced native fluorescence of LIN in phosphate buffer (pH 5 at 380 nm upon excitation at 260 nm. Experimental factors affecting fluorescence intensity were optimized. Linearity was obtained over concentration ranges 50-500, 10-60 and 20-400 ng mL-1 for methods A, B and C, respectively. The developed methods were validated and successfully applied for determination of the cited drugs in tablets.

The question of an upper bound on entropy

International Nuclear Information System (INIS)

Qadir, A.

1982-08-01

We discuss the possibility, and significance, of an upper bound on entropy in the light of the arguments of Bekenstein and Unruh and Wald. We obtain a stricter bound than Bekenstein does, and point out some limitations with regard to its significance. (author)

Optimal Two Parameter Bounds for the Seiffert Mean

Directory of Open Access Journals (Sweden)

Hui Sun

2013-01-01

Full Text Available We obtain sharp bounds for the Seiffert mean in terms of a two parameter family of means. Our results generalize and extend the recent bounds presented in the Journal of Inequalities and Applications (2012 and Abstract and Applied Analysis (2012.

Clinical Trials: A Crucial Key to Human Health Research

Science.gov (United States)

... Past Issues Clinical Trials: A Crucial Key to Human Health Research Past Issues / Summer 2006 Table of Contents ... Javascript on. Photo: PhotoDisc At the forefront of human health research today are clinical trials—studies that use ...

Effects of aqueous extract of Ruta graveolens and its ingredients on cytochrome P450, uridine diphosphate (UDP-glucuronosyltransferase, and reduced nicotinamide adenine dinucleotide (phosphate (NAD(PH-quinone oxidoreductase in mice

Directory of Open Access Journals (Sweden)

Yune-Fang Ueng

2015-09-01

Full Text Available Ruta graveolens (the common rue has been used for various therapeutic purposes, including relief of rheumatism and treatment of circulatory disorder. To elucidate the effects of rue on main drug-metabolizing enzymes, effects of an aqueous extract of the aerial part of rue and its ingredients on cytochrome P450 (P450/CYP, uridine diphosphate (UDP-glucuronosyltransferase, and reduced nicotinamide adenine dinucleotide (phosphate (NAD(PH:quinone oxidoreductase were studied in C57BL/6JNarl mice. Oral administration of rue extract to males increased hepatic Cyp1a and Cyp2b activities in a dose-dependent manner. Under a 7-day treatment regimen, rue extract (0.5 g/kg induced hepatic Cyp1a and Cyp2b activities and protein levels in males and females. This treatment increased hepatic UDP-glucuronosyltransferase activity only in males. However, NAD(PH:quinone oxidoreductase activity remained unchanged. Based on the contents of rutin and furanocoumarins of mouse dose of rue extract, rutin increased hepatic Cyp1a activity and the mixture of furanocoumarins (Fmix increased Cyp2b activities in males. The mixture of rutin and Fmix increased Cyp1a and Cyp2b activities. These results revealed that rutin and Fmix contributed at least in part to the P450 induction by rue.

Rigorous bounds on the free energy of electron-phonon models

NARCIS (Netherlands)

Raedt, Hans De; Michielsen, Kristel

1997-01-01

We present a collection of rigorous upper and lower bounds to the free energy of electron-phonon models with linear electron-phonon interaction. These bounds are used to compare different variational approaches. It is shown rigorously that the ground states corresponding to the sharpest bounds do

Impacto psicosocial del síndrome demencial en cuidadores cruciales Psychosocial impact of demential syndrome in crucial care givers

Directory of Open Access Journals (Sweden)

Juan Carlos LLibre Guerra

2008-03-01

Full Text Available Las demencias, entidades de elevada frecuencia en el adulto mayor, constituyen un creciente problema de salud en países con una alta expectativa de vida como el nuestro, no solo por su magnitud, sino por su repercusión a nivel individual, familiar y social. Se presenta un estudio descriptivo de corte transversal, realizado en el período comprendido entre enero de 2003 y enero de 2005, en las áreas de salud del municipio Marianao, con el objetivo de determinar el impacto psicosocial del síndrome demencial en cuidadores cruciales. Se visitaron 110 cuidadores de pacientes con demencia y enfermedad de Alzheimer diagnosticados de acuerdo con los criterios del DSM-IV. Los cuidadores cruciales de los pacientes con demencia correspondieron en su mayoría a mujeres casadas, esposa o hijas del paciente, en la quinta década de la vida, amas de casa, y con un nivel medio de escolaridad. El cuidador dedica alrededor de 12 h diarias al cuidado del paciente, la mayor parte en la supervisión. Se evidenció afectación psicológica en el 89 % de los cuidadores. El nivel de sobrecarga o estrés en la muestra es significativamente elevado. Los cuidadores consideran como primera prioridad información acerca de la enfermedad y atención al paciente. Se recomienda realizar un plan de intervención educativa dirigido a los cuidadores, que permita reducir la sobrecarga física, psicológica y económica del cuidado y mejorar su calidad de vida.The dementias, entities of an elevated frequency in the older adult, are an increasing health problem in countries with a high life expectancy at birth as ours, not only because of their magnitude, but also because of their repercussion at the individual, familiar and social levels. A descriptive cross-sectional study was undertaken from January 2003 to January 2005 in the health areas of Marianao municipality with the objective of determining the psychosocial impact of the demential syndrome in crucial care givers. 110

Possible circumvention of Parker's bound on galactic magnetic monopoles

International Nuclear Information System (INIS)

Dicus, D.A.; Teplitz, V.L.

1983-04-01

There is a possibility that a magnetic monople has observed. The monopole density implied by the observation appears to violate bounds on the density of such particles derived from the total mass density of the universe and from the existence of galactic magnetic fields. We show that the observation is not inconsistent with these bounds if the monopoles and antimonopoles are bound into positronium - like states with principal quantum n high enough so that the earth's magnetic field will break them apart, but small enough so that the weaker galactic mangetic field will not. We determine a range of values for n and show that lifetimes for such bound states are longer than the current age of the universe

Bounds on the Effect of Progressive Structural Degradation

DEFF Research Database (Denmark)

Achtziger, W.; Bendsøe, Martin P; Taylor, John E.

1998-01-01

Problem formulations are presented for the evaluation of upper and lower bounds on the effect of progressive structural degradation. For the purposes of this study, degradation effect is measured by an increase in global structural compliance (flexibility). Thus the slated bounds are given simply...

Bounds for Tail Probabilities of the Sample Variance

Directory of Open Access Journals (Sweden)

Van Zuijlen M

2009-01-01

Full Text Available We provide bounds for tail probabilities of the sample variance. The bounds are expressed in terms of Hoeffding functions and are the sharpest known. They are designed having in mind applications in auditing as well as in processing data related to environment.

Bounds on the Effect of Progressive Structural Degradation

DEFF Research Database (Denmark)

Achtziger, Wolfgang; Bendsøe, Martin P; Taylor, John E.

1997-01-01

Problem formulations are presented for the evaluation of upper and lower bounds on the effect of progressive structural degradation. For the purposes of this study, degradation effect is measured by an increase in global structural compliance (flexibility). Thus the stated bounds are given simply...

Dynamic Garment Simulation based on Hybrid Bounding Volume Hierarchy

Directory of Open Access Journals (Sweden)

Zhu Dongyong

2016-12-01

Full Text Available In order to solve the computing speed and efficiency problem of existing dynamic clothing simulation, this paper presents a dynamic garment simulation based on a hybrid bounding volume hierarchy. It firstly uses MCASG graph theory to do the primary segmentation for a given three-dimensional human body model. And then it applies K-means cluster to do the secondary segmentation to collect the human body’s upper arms, lower arms, upper legs, lower legs, trunk, hip and woman’s chest as the elementary units of dynamic clothing simulation. According to different shapes of these elementary units, it chooses the closest and most efficient hybrid bounding box to specify these units, such as cylinder bounding box and elliptic cylinder bounding box. During the process of constructing these bounding boxes, it uses the least squares method and slices of the human body to get the related parameters. This approach makes it possible to use the least amount of bounding boxes to create close collision detection regions for the appearance of the human body. A spring-mass model based on a triangular mesh of the clothing model is finally constructed for dynamic simulation. The simulation result shows the feasibility and superiority of the method described.

Viscosity bound violation in holographic solids and the viscoelastic response

Energy Technology Data Exchange (ETDEWEB)

Alberte, Lasma [Abdus Salam International Centre for Theoretical Physics (ICTP),Strada Costiera 11, 34151, Trieste (Italy); Baggioli, Matteo [Institut de Física d’Altes Energies (IFAE),The Barcelona Institute of Science and Technology (BIST),Campus UAB, 08193 Bellaterra, Barcelona (Spain); Department of Physics, Institute for Condensed Matter Theory, University of Illinois,1110 W. Green Street, Urbana, IL 61801 (United States); Pujolàs, Oriol [Institut de Física d’Altes Energies (IFAE),The Barcelona Institute of Science and Technology (BIST),Campus UAB, 08193 Bellaterra, Barcelona (Spain)

2016-07-14

We argue that the Kovtun-Son-Starinets (KSS) lower bound on the viscosity to entropy density ratio holds in fluid systems but is violated in solid materials with a non-zero shear elastic modulus. We construct explicit examples of this by applying the standard gauge/gravity duality methods to massive gravity and show that the KSS bound is clearly violated in black brane solutions whenever the massive gravity theories are of solid type. We argue that the physical reason for the bound violation relies on the viscoelastic nature of the mechanical response in these materials. We speculate on whether any real-world materials can violate the bound and discuss a possible generalization of the bound that involves the ratio of the shear elastic modulus to the pressure.

Viscosity bound violation in holographic solids and the viscoelastic response

International Nuclear Information System (INIS)

Alberte, Lasma; Baggioli, Matteo; Pujolàs, Oriol

2016-01-01

We argue that the Kovtun-Son-Starinets (KSS) lower bound on the viscosity to entropy density ratio holds in fluid systems but is violated in solid materials with a non-zero shear elastic modulus. We construct explicit examples of this by applying the standard gauge/gravity duality methods to massive gravity and show that the KSS bound is clearly violated in black brane solutions whenever the massive gravity theories are of solid type. We argue that the physical reason for the bound violation relies on the viscoelastic nature of the mechanical response in these materials. We speculate on whether any real-world materials can violate the bound and discuss a possible generalization of the bound that involves the ratio of the shear elastic modulus to the pressure.

Bound states in curved quantum waveguides

International Nuclear Information System (INIS)

Exner, P.; Seba, P.

1987-01-01

We study free quantum particle living on a curved planar strip Ω of a fixed width d with Dirichlet boundary conditions. It can serve as a model for electrons in thin films on a cylindrical-type substrate, or in a curved quantum wire. Assuming that the boundary of Ω is infinitely smooth and its curvature decays fast enough at infinity, we prove that a bound state with energy below the first transversal mode exists for all sufficiently small d. A lower bound on the critical width is obtained using the Birman-Schwinger technique. (orig.)

Bound constrained quadratic programming via piecewise

DEFF Research Database (Denmark)

Madsen, Kaj; Nielsen, Hans Bruun; Pinar, M. C.

1999-01-01

of a symmetric, positive definite matrix, and is solved by Newton iteration with line search. The paper describes the algorithm and its implementation including estimation of lambda/sub 1/ , how to get a good starting point for the iteration, and up- and downdating of Cholesky factorization. Results of extensive......We consider the strictly convex quadratic programming problem with bounded variables. A dual problem is derived using Lagrange duality. The dual problem is the minimization of an unconstrained, piecewise quadratic function. It involves a lower bound of lambda/sub 1/ , the smallest eigenvalue...

Dynamics of bleomycin interaction with a strongly bound hairpin DNA substrate, and implications for cleavage of the bound DNA.

Science.gov (United States)

Bozeman, Trevor C; Nanjunda, Rupesh; Tang, Chenhong; Liu, Yang; Segerman, Zachary J; Zaleski, Paul A; Wilson, W David; Hecht, Sidney M

2012-10-31

Recent studies involving DNAs bound strongly by bleomycins have documented that such DNAs are degraded by the antitumor antibiotic with characteristics different from those observed when studying the cleavage of randomly chosen DNAs in the presence of excess Fe·BLM. In the present study, surface plasmon resonance has been used to characterize the dynamics of BLM B(2) binding to a strongly bound hairpin DNA, to define the effects of Fe(3+), salt, and temperature on BLM-DNA interaction. One strong primary DNA binding site, and at least one much weaker site, were documented. In contrast, more than one strong cleavage site was found, an observation also made for two other hairpin DNAs. Evidence is presented for BLM equilibration between the stronger and weaker binding sites in a way that renders BLM unavailable to other, less strongly bound DNAs. Thus, enhanced binding to a given site does not necessarily result in increased DNA degradation at that site; i.e., for strongly bound DNAs, the facility of DNA cleavage must involve other parameters in addition to the intrinsic rate of C-4' H atom abstraction from DNA sugars.

Rhodium-catalyzed C-H bond activation for the synthesis of quinonoid compounds: Significant Anti-Trypanosoma cruzi activities and electrochemical studies of functionalized quinones.

Science.gov (United States)

Jardim, Guilherme A M; Silva, Thaissa L; Goulart, Marilia O F; de Simone, Carlos A; Barbosa, Juliana M C; Salomão, Kelly; de Castro, Solange L; Bower, John F; da Silva Júnior, Eufrânio N

2017-08-18

Thirty four halogen and selenium-containing quinones, synthesized by rhodium-catalyzed C-H bond activation and palladium-catalyzed cross-coupling reactions, were evaluated against bloodstream trypomastigotes of T. cruzi. We have identified fifteen compounds with IC 50 /24 h values of less than 2 μM. Electrochemical studies on A-ring functionalized naphthoquinones were also performed aiming to correlate redox properties with trypanocidal activity. For instance, (E)-5-styryl-1,4-naphthoquinone 59 and 5,8-diiodo-1,4-naphthoquinone 3, which are around fifty fold more active than the standard drug benznidazole, are potential derivatives for further investigation. These compounds represent powerful new agents useful in Chagas disease therapy. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Upper and lower bounds in nonrelativistic scattering theory

International Nuclear Information System (INIS)

Darewych, J.W.; Pooran, R.

1980-01-01

We consider the problem of determining rigorous upper and lower bounds to the difference between the exact and approximate scattering phase shift, for the case of central potential scattering. The present work is based on the Kato identities and the phase-amplitude formalism of potential scattering developed by Calogero. For nonstationary approximations, a new first-order (in small quantities) bound is established which is particularly useful for partial waves other than s waves. Similar, but second-order, bounds are established for approximations which are stationary. Some previous results, based on the use of the Lippman--Schwinger equation are generalized, and some new bounds are established. These are illustrated, and compared to previous results, by a simple example. We discuss the advantages and disadvantages of the present results in comparison to those derived previously. Finally, we present the generalization of some of the present formalism to the case of many-channel scattering involving many-particle systems, and discuss some of the difficulties of their practical implementation

HiggsBounds-4. Improved tests of extended Higgs sectors against exclusion bounds from LEP, the Tevatron and the LHC

Energy Technology Data Exchange (ETDEWEB)

Bechtle, Philip [Bonn Univ. (Germany). Physikalisches Inst.; Heinemeyer, Sven [Instituto de Fisica de Cantabria (CSIC-UC), Santander (Spain); Staal, Oscar [Stockholm Univ. (Sweden). Dept. of Physics; Stefaniak, Tim; Williams, Karina E. [Bonn Univ. (Germany). Physikalisches Inst.; Bonn Univ. (Germany). Bethe Center for Theoretical Physics; Weiglein, Georg [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Brein, Oliver

2013-12-15

We describe the new developments in version 4 of the public computer code HiggsBounds. HiggsBounds is a tool to test models with arbitrary Higgs sectors, containing both neutral and charged Higgs bosons, against the published exclusion bounds from Higgs searches at the LEP, Tevatron and LHC experiments. From the model predictions for the Higgs masses, branching ratios, production cross sections and total decay widths - which are specified by the user in the input for the program - the code calculates the predicted signal rates for the search channels considered in the experimental data. The signal rates are compared to the expected and observed cross section limits from the Higgs searches to determine whether a point in the model parameter space is excluded at 95% confidence level. In this paper we present a modification of the HiggsBounds main algorithm that extends the exclusion test in order to ensure that it provides useful results in the presence of one or more significant excesses in the data, corresponding to potential Higgs signals. We also describe a new method to test whether the limits from an experimental search performed under certain model assumptions can be applied to a different theoretical model. Further developments discussed here include a framework to take into account theoretical uncertainties on the Higgs mass predictions, and the possibility to obtain the {chi}{sup 2} likelihood of Higgs exclusion limits from LEP. Extensions to the user subroutines from earlier versions of HiggsBounds are described. The new features are demonstrated by additional example programs.

HiggsBounds-4. Improved tests of extended Higgs sectors against exclusion bounds from LEP, the Tevatron and the LHC

International Nuclear Information System (INIS)

Bechtle, Philip; Staal, Oscar; Brein, Oliver

2013-12-01

We describe the new developments in version 4 of the public computer code HiggsBounds. HiggsBounds is a tool to test models with arbitrary Higgs sectors, containing both neutral and charged Higgs bosons, against the published exclusion bounds from Higgs searches at the LEP, Tevatron and LHC experiments. From the model predictions for the Higgs masses, branching ratios, production cross sections and total decay widths - which are specified by the user in the input for the program - the code calculates the predicted signal rates for the search channels considered in the experimental data. The signal rates are compared to the expected and observed cross section limits from the Higgs searches to determine whether a point in the model parameter space is excluded at 95% confidence level. In this paper we present a modification of the HiggsBounds main algorithm that extends the exclusion test in order to ensure that it provides useful results in the presence of one or more significant excesses in the data, corresponding to potential Higgs signals. We also describe a new method to test whether the limits from an experimental search performed under certain model assumptions can be applied to a different theoretical model. Further developments discussed here include a framework to take into account theoretical uncertainties on the Higgs mass predictions, and the possibility to obtain the χ 2 likelihood of Higgs exclusion limits from LEP. Extensions to the user subroutines from earlier versions of HiggsBounds are described. The new features are demonstrated by additional example programs.

An Interval Bound Algorithm of optimizing reactor core loading pattern by using reactivity interval schema

International Nuclear Information System (INIS)

Gong Zhaohu; Wang Kan; Yao Dong

2011-01-01

Highlights: → We present a new Loading Pattern Optimization method - Interval Bound Algorithm (IBA). → IBA directly uses the reactivity of fuel assemblies and burnable poison. → IBA can optimize fuel assembly orientation in a coupled way. → Numerical experiment shows that IBA outperforms genetic algorithm and engineers. → We devise DDWF technique to deal with multiple objectives and constraints. - Abstract: In order to optimize the core loading pattern in Nuclear Power Plants, the paper presents a new optimization method - Interval Bound Algorithm (IBA). Similar to the typical population based algorithms, e.g. genetic algorithm, IBA maintains a population of solutions and evolves them during the optimization process. IBA acquires the solution by statistical learning and sampling the control variable intervals of the population in each iteration. The control variables are the transforms of the reactivity of fuel assemblies or the worth of burnable poisons, which are the crucial heuristic information for loading pattern optimization problems. IBA can deal with the relationship between the dependent variables by defining the control variables. Based on the IBA algorithm, a parallel Loading Pattern Optimization code, named IBALPO, has been developed. To deal with multiple objectives and constraints, the Dynamic Discontinuous Weight Factors (DDWF) for the fitness function have been used in IBALPO. Finally, the code system has been used to solve a realistic reloading problem and a better pattern has been obtained compared with the ones searched by engineers and genetic algorithm, thus the performance of the code is proved.

A proteomic view at the biochemistry of syntrophic butyrate oxidation in Syntrophomonas wolfei.

Directory of Open Access Journals (Sweden)

Alexander Schmidt

Full Text Available In syntrophic conversion of butyrate to methane and CO2, butyrate is oxidized to acetate by secondary fermenting bacteria such as Syntrophomonas wolfei in close cooperation with methanogenic partner organisms, e.g., Methanospirillum hungatei. This process involves an energetically unfavourable shift of electrons from the level of butyryl-CoA oxidation to the substantially lower redox potential of proton and/or CO2 reduction, in order to transfer these electrons to the methanogenic partner via hydrogen and/or formate. In the present study, all prominent membrane-bound and soluble proteins expressed in S. wolfei specifically during syntrophic growth with butyrate, in comparison to pure-culture growth with crotonate, were examined by one- and two-dimensional gel electrophoresis, and identified by peptide fingerprinting-mass spectrometry. A membrane-bound, externally oriented, quinone-linked formate dehydrogenase complex was expressed at high level specifically during syntrophic butyrate oxidation, comprising a selenocystein-linked catalytic subunit with a membrane-translocation pathway signal (TAT, a membrane-bound iron-sulfur subunit, and a membrane-bound cytochrome. Soluble hydrogenases were expressed at high levels specifically during growth with crotonate. The results were confirmed by native protein gel electrophoresis, by formate dehydrogenase and hydrogenase-activity staining, and by analysis of formate dehydrogenase and hydrogenase activities in intact cells and cell extracts. Furthermore, constitutive expression of a membrane-bound, internally oriented iron-sulfur oxidoreductase (DUF224 was confirmed, together with expression of soluble electron-transfer flavoproteins (EtfAB and two previously identified butyryl-CoA dehydrogenases. Our findings allow to depict an electron flow scheme for syntrophic butyrate oxidation in S. wolfei. Electrons derived from butyryl-CoA are transferred through a membrane-bound EtfAB:quinone oxidoreductase (DUF

Upper bound on the capacity of constrained three-dimensional codes

DEFF Research Database (Denmark)

Forchhammer, Søren

2000-01-01

An upper bound on the capacity of constrained three-dimensional codes is presented. The bound for two-dimensional codes of Calkin and Wilf (see SIAM Journal of Discrete Mathematics, vol.11, no.1, p.54-60, 1998) was extended to three dimensions by Nagy and Zeger. Both bounds apply to first order s...

Relevance of the ICRP biokinetic model for dietary organically bound tritium

International Nuclear Information System (INIS)

Trivedi, A.

1999-10-01

Ingested dietary tritium can participate in metabolic processes, and become synthesized into organically bound tritium in the tissues and organs. The distribution and retention of the organically bound tritium throughout the body are much different than tritium in the body water. The International Commission on Radiological Protection (ICRP) Publication 56 (1989) has a biokinetic model to calculate dose from the ingestion of organically bound dietary tritium. The model predicts that the dose from the ingestion of organically bound dietary tritium is about 2.3 times higher than from the ingestion of the same activity of tritiated water. Under steady-state conditions, the calculated dose rate (using the first principle approach) from the ingestion of dietary organically bound tritium can be twice that from the ingestion of tritiated water. For an adult, the upper-bound dose estimate for the ingestion of dietary organically bound tritium is estimated to be close to 2.3 times higher than that of tritiated water. Therefore, given the uncertainty in the dose calculation with respect to the actual relevant dose, the ICRP biokinetic model for organically bound tritium is sufficient for dosimetry for adults. (author)

Dielectric structures with bound modes for microcavity lasers

NARCIS (Netherlands)

Visser, P.M.; Allaart, K.; Lenstra, D.

2002-01-01

Cavity modes of dielectric microsphcres and vertical cavity surface emitting lasers, in spite of their high Q, are never exactly bound, but have a finite width due to leakage at the borders. We propose types of microstructures that sustain three-dimensionally bound modes of the radiation field when

Towards an abstract parallel branch and bound machine

NARCIS (Netherlands)

A. de Bruin (Arie); G.A.P. Kindervater (Gerard); H.W.J.M. Trienekens

1995-01-01

textabstractMany (parallel) branch and bound algorithms look very different from each other at first glance. They exploit, however, the same underlying computational model. This phenomenon can be used to define branch and bound algorithms in terms of a set of basic rules that are applied in a

Bound state and localization of excitation in many-body open systems

Science.gov (United States)

Cui, H. T.; Shen, H. Z.; Hou, S. C.; Yi, X. X.

2018-04-01

We study the exact bound state and time evolution for single excitations in one-dimensional X X Z spin chains within a non-Markovian reservoir. For the bound state, a common feature is the localization of single excitations, which means the spontaneous emission of excitations into the reservoir is prohibited. Exceptionally, the pseudo-bound state can be found, for which the single excitation has a finite probability of emission into the reservoir. In addition, a critical energy scale for bound states is also identified, below which only one bound state exists, and it is also the pseudo-bound state. The effect of quasirandom disorder in the spin chain is also discussed; such disorder induces the single excitation to locate at some spin sites. Furthermore, to display the effect of bound state and disorder on the preservation of quantum information, the time evolution of single excitations in spin chains is studied exactly. An interesting observation is that the excitation can stay at its initial location with high probability only when the bound state and disorder coexist. In contrast, when either one of them is absent, the information of the initial state can be erased completely or becomes mixed. This finding shows that the combination of bound state and disorder can provide an ideal mechanism for quantum memory.

Bounded Rationality in Transposition Processes

DEFF Research Database (Denmark)

Vollaard, Hans; Martinsen, Dorte Sindbjerg

2014-01-01

Studies explaining the timeliness and correctness of the transposition of EU directives into national legislation have provided rather inconclusive findings. They do not offer a clear-cut prediction concerning the transposition of the patients’ rights directive, which is one of the first that con......Studies explaining the timeliness and correctness of the transposition of EU directives into national legislation have provided rather inconclusive findings. They do not offer a clear-cut prediction concerning the transposition of the patients’ rights directive, which is one of the first...... that concerns the organisation and financing of national healthcare systems. This article applies the perspective of bounded rationality to explain (irregularities in) the timely and correct transposition of EU directives. The cognitive and organisational constraints long posited by the bounded rationality...

Bound on viscosity and the generalized second law of thermodynamics

International Nuclear Information System (INIS)

Fouxon, Itzhak; Betschart, Gerold; Bekenstein, Jacob D.

2008-01-01

We describe a new paradox for ideal fluids. It arises in the accretion of an ideal fluid onto a black hole, where, under suitable boundary conditions, the flow can violate the generalized second law of thermodynamics. The paradox indicates that there is in fact a lower bound to the correlation length of any real fluid, the value of which is determined by the thermodynamic properties of that fluid. We observe that the universal bound on entropy, itself suggested by the generalized second law, puts a lower bound on the correlation length of any fluid in terms of its specific entropy. With the help of a new, efficient estimate for the viscosity of liquids, we argue that this also means that viscosity is bounded from below in a way reminiscent of the conjectured Kovtun-Son-Starinets lower bound on the ratio of viscosity to entropy density. We conclude that much light may be shed on the Kovtun-Son-Starinets bound by suitable arguments based on the generalized second law

Lower Bounds in the Asymmetric External Memory Model

DEFF Research Database (Denmark)

Jacob, Riko; Sitchinava, Nodari

2017-01-01

Motivated by the asymmetric read and write costs of emerging non-volatile memory technologies, we study lower bounds for the problems of sorting, permuting and multiplying a sparse matrix by a dense vector in the asymmetric external memory model (AEM). Given an AEM with internal (symmetric) memory...... of size M, transfers between symmetric and asymmetric memory in blocks of size B and the ratio ω between write and read costs, we show Ω(min (N, ωN/B logω M/B N/B) lower bound for the cost of permuting N input elements. This lower bound also applies to the problem of sorting N elements. This proves...

Volume dependence of N-body bound states

Science.gov (United States)

König, Sebastian; Lee, Dean

2018-04-01

We derive the finite-volume correction to the binding energy of an N-particle quantum bound state in a cubic periodic volume. Our results are applicable to bound states with arbitrary composition and total angular momentum, and in any number of spatial dimensions. The only assumptions are that the interactions have finite range. The finite-volume correction is a sum of contributions from all possible breakup channels. In the case where the separation is into two bound clusters, our result gives the leading volume dependence up to exponentially small corrections. If the separation is into three or more clusters, there is a power-law factor that is beyond the scope of this work, however our result again determines the leading exponential dependence. We also present two independent methods that use finite-volume data to determine asymptotic normalization coefficients. The coefficients are useful to determine low-energy capture reactions into weakly bound states relevant for nuclear astrophysics. Using the techniques introduced here, one can even extract the infinite-volume energy limit using data from a single-volume calculation. The derived relations are tested using several exactly solvable systems and numerical examples. We anticipate immediate applications to lattice calculations of hadronic, nuclear, and cold atomic systems.

Scattering theory methods for bound state problems

International Nuclear Information System (INIS)

Raphael, R.B.; Tobocman, W.

1978-01-01

For the analysis of the properties of a bound state system one may use in place of the Schroedinger equation the Lippmann-Schwinger (LS) equation for the wave function or the LS equation for the reactance operator. Use of the LS equation for the reactance operator constrains the solution to have correct asymptotic behaviour, so this approach would appear to be desirable when the bound state wave function is to be used to calculate particle transfer form factors. The Schroedinger equation based N-level analysis of the s-wave bound states of a square well is compared to the ones based on the LS equation. It is found that the LS equation methods work better than the Schroedinger equation method. The method that uses the LS equation for the wave function gives the best results for the wave functions while the method that uses the LS equation for the reactance operator gives the best results for the binding energies. The accuracy of the reactance operator based method is remarkably insensitive to changes in the oscillator constant used for the harmonic oscillator function basis set. It is also remarkably insensitive to the number of nodes in the bound state wave function. (Auth.)

Efficiency bounds for nonequilibrium heat engines

International Nuclear Information System (INIS)

Mehta, Pankaj; Polkovnikov, Anatoli

2013-01-01

We analyze the efficiency of thermal engines (either quantum or classical) working with a single heat reservoir like an atmosphere. The engine first gets an energy intake, which can be done in an arbitrary nonequilibrium way e.g. combustion of fuel. Then the engine performs the work and returns to the initial state. We distinguish two general classes of engines where the working body first equilibrates within itself and then performs the work (ergodic engine) or when it performs the work before equilibrating (non-ergodic engine). We show that in both cases the second law of thermodynamics limits their efficiency. For ergodic engines we find a rigorous upper bound for the efficiency, which is strictly smaller than the equivalent Carnot efficiency. I.e. the Carnot efficiency can be never achieved in single reservoir heat engines. For non-ergodic engines the efficiency can be higher and can exceed the equilibrium Carnot bound. By extending the fundamental thermodynamic relation to nonequilibrium processes, we find a rigorous thermodynamic bound for the efficiency of both ergodic and non-ergodic engines and show that it is given by the relative entropy of the nonequilibrium and initial equilibrium distributions. These results suggest a new general strategy for designing more efficient engines. We illustrate our ideas by using simple examples. -- Highlights: ► Derived efficiency bounds for heat engines working with a single reservoir. ► Analyzed both ergodic and non-ergodic engines. ► Showed that non-ergodic engines can be more efficient. ► Extended fundamental thermodynamic relation to arbitrary nonequilibrium processes

Computing variational bounds for flow through random aggregates of Spheres

International Nuclear Information System (INIS)

Berryman, J.G.

1983-01-01

Known formulas for variational bounds on Darcy's constant for slow flow through porous media depend on two-point and three-poiint spatial correlation functions. Certain bounds due to Prager and Doi depending only a two-point correlation functions have been calculated for the first time for random aggregates of spheres with packing fractions (eta) up to eta = 0.64. Three radial distribution functions for hard spheres were tested for eta up to 0.49: (1) the uniform distribution or ''well-stirred approximation,'' (2) the Percus Yevick approximation, and (3) the semi-empirical distribution of Verlet and Weis. The empirical radial distribution functions of Benett andd Finney were used for packing fractions near the random-close-packing limit (eta/sub RCP/dapprox.0.64). An accurate multidimensional Monte Carlo integration method (VEGAS) developed by Lepage was used to compute the required two-point correlation functions. The results show that Doi's bounds are preferred for eta>0.10 while Prager's bounds are preferred for eta>0.10. The ''upper bounds'' computed using the well-stirred approximation actually become negative (which is physically impossible) as eta increases, indicating the very limited value of this approximation. The other two choices of radial distribution function give reasonable results for eta up to 0.49. However, these bounds do not decrease with eta as fast as expected for large eta. It is concluded that variational bounds dependent on three-point correlation functions are required to obtain more accurate bounds on Darcy's constant for large eta

Bounding the space of holographic CFTs with chaos

Energy Technology Data Exchange (ETDEWEB)

Perlmutter, Eric [Department of Physics, Princeton University,Jadwin Hall, Princeton, NJ 08544 (United States)

2016-10-13

Thermal states of quantum systems with many degrees of freedom are subject to a bound on the rate of onset of chaos, including a bound on the Lyapunov exponent, λ{sub L}≤2π/β. We harness this bound to constrain the space of putative holographic CFTs and their would-be dual theories of AdS gravity. First, by studying out-of-time-order four-point functions, we discuss how λ{sub L}=2π/β in ordinary two-dimensional holographic CFTs is related to properties of the OPE at strong coupling. We then rule out the existence of unitary, sparse two-dimensional CFTs with large central charge and a set of higher spin currents of bounded spin; this implies the inconsistency of weakly coupled AdS{sub 3} higher spin gravities without infinite towers of gauge fields, such as the SL(N) theories. This fits naturally with the structure of higher-dimensional gravity, where finite towers of higher spin fields lead to acausality. On the other hand, unitary CFTs with classical W{sub ∞}[λ] symmetry, dual to 3D Vasiliev or hs[λ] higher spin gravities, do not violate the chaos bound, instead exhibiting no chaos: λ{sub L}=0. Independently, we show that such theories violate unitarity for |λ|>2. These results encourage a tensionless string theory interpretation of the 3D Vasiliev theory.

Automatic bounding estimation in modified NLMS algorithm

International Nuclear Information System (INIS)

Shahtalebi, K.; Doost-Hoseini, A.M.

2002-01-01

Modified Normalized Least Mean Square algorithm, which is a sign form of Nlm based on set-membership (S M) theory in the class of optimal bounding ellipsoid (OBE) algorithms, requires a priori knowledge of error bounds that is unknown in most applications. In a special but popular case of measurement noise, a simple algorithm has been proposed. With some simulation examples the performance of algorithm is compared with Modified Normalized Least Mean Square

Lower Bounds for External Memory Dictionaries

DEFF Research Database (Denmark)

Brodal, Gerth Stølting; Fagerberg, Rolf

2003-01-01

We study trade-offs between the update time and the query time for comparison based external memory dictionaries. The main contributions of this paper are two lower bound trade offs between the I/O complexity of member queries and insertions: If N < M insertions perform at most δ · N/B I/Os, then......We study trade-offs between the update time and the query time for comparison based external memory dictionaries. The main contributions of this paper are two lower bound trade offs between the I/O complexity of member queries and insertions: If N

Quantum engine efficiency bound beyond the second law of thermodynamics.

Science.gov (United States)

Niedenzu, Wolfgang; Mukherjee, Victor; Ghosh, Arnab; Kofman, Abraham G; Kurizki, Gershon

2018-01-11

According to the second law, the efficiency of cyclic heat engines is limited by the Carnot bound that is attained by engines that operate between two thermal baths under the reversibility condition whereby the total entropy does not increase. Quantum engines operating between a thermal and a squeezed-thermal bath have been shown to surpass this bound. Yet, their maximum efficiency cannot be determined by the reversibility condition, which may yield an unachievable efficiency bound above unity. Here we identify the fraction of the exchanged energy between a quantum system and a bath that necessarily causes an entropy change and derive an inequality for this change. This inequality reveals an efficiency bound for quantum engines energised by a non-thermal bath. This bound does not imply reversibility, unless the two baths are thermal. It cannot be solely deduced from the laws of thermodynamics.

Capacity bounds for parallel IM-DD optical wireless channels

KAUST Repository

Chaaban, Anas; Rezki, Zouheir; Alouini, Mohamed-Slim

2016-01-01

A system consisting of parallel intensity-modulation direct-detection optical wireless channels with a total average intensity constraint is studied. Capacity upper and lower bounds for this system are derived. If channel-state information is available at the transmitter, the bounds have to be optimized with respect to intensity allocation over the parallel channels. The optimization of the lower bound is non-convex, however, the Karush-Kuhn-Tucker conditions can be used to find a list of possible solutions one of which is optimal. The optimal solution can then be found by an exhaustive search algorithm, which is computationally expensive. To overcome this, we propose a low-complexity intensity allocation algorithm which is nearly optimal. The optimized capacity lower bound coincides with the capacity at high signal-to-noise ratio. © 2016 IEEE.

Capacity bounds for parallel IM-DD optical wireless channels

KAUST Repository

Chaaban, Anas

2016-07-26

A system consisting of parallel intensity-modulation direct-detection optical wireless channels with a total average intensity constraint is studied. Capacity upper and lower bounds for this system are derived. If channel-state information is available at the transmitter, the bounds have to be optimized with respect to intensity allocation over the parallel channels. The optimization of the lower bound is non-convex, however, the Karush-Kuhn-Tucker conditions can be used to find a list of possible solutions one of which is optimal. The optimal solution can then be found by an exhaustive search algorithm, which is computationally expensive. To overcome this, we propose a low-complexity intensity allocation algorithm which is nearly optimal. The optimized capacity lower bound coincides with the capacity at high signal-to-noise ratio. © 2016 IEEE.

NAD(P)H quinone oxidoreductase 1 inhibits the proteasomal degradation of homocysteine-induced endoplasmic reticulum protein

Energy Technology Data Exchange (ETDEWEB)

Maeda, Tomoji, E-mail: t-maeda@nichiyaku.ac.jp [Department of Neuroscience, School of Pharmacy, Iwate Medical University, 2-1-1 Nishitokuta, Yahaba-Cho, Shiwagun, Iwate, 028-3603 (Japan); Tanabe-Fujimura, Chiaki; Fujita, Yu; Abe, Chihiro; Nanakida, Yoshino; Zou, Kun; Liu, Junjun; Liu, Shuyu [Department of Neuroscience, School of Pharmacy, Iwate Medical University, 2-1-1 Nishitokuta, Yahaba-Cho, Shiwagun, Iwate, 028-3603 (Japan); Nakajima, Toshihiro [Institute of Medical Science, Tokyo Medical University, 6-1-1 Shinjyuku, Shinjyuku, Tokyo, Tokyo, 160-8402 (Japan); Komano, Hiroto, E-mail: hkomano@iwate-med.ac.jp [Department of Neuroscience, School of Pharmacy, Iwate Medical University, 2-1-1 Nishitokuta, Yahaba-Cho, Shiwagun, Iwate, 028-3603 (Japan)

2016-05-13

Homocysteine-induced endoplasmic reticulum (ER) protein (Herp) is an ER stress-inducible key regulatory component of ER-associated degradation (ERAD) that has been implicated in insulin hypersecretion in diabetic mouse models. Herp expression is tightly regulated. Additionally, Herp is a highly labile protein and interacts with various proteins, which are characteristic features of ubiquitinated protein. Previously, we reported that ubiquitination is not required for Herp degradation. In addition, we found that the lysine residues of Herp (which are ubiquitinated by E3 ubiquitin ligase) are not sufficient for regulation of Herp degradation. In this study, we found that NAD(P)H quinone oxidoreductase 1 (NQO1)-mediated targeting of Herp to the proteasome was involved in Herp degradation. In addition, we found that Herp protein levels were markedly elevated in synoviolin-null cells. The E3 ubiquitin ligase synoviolin is a central component of ERAD and is involved in the degradation of nuclear factor E2-related factor-2 (Nrf2), which regulates cellular reactive oxygen species. Additionally, NQO1 is a target of Nrf2. Thus, our findings indicated that NQO1 could stabilize Herp protein expression via indirect regulation of synoviolin. -- Highlights: •Herp interacts with NQO1. •NQO1 regulates Herp degradation.

NAD(P)H quinone oxidoreductase 1 inhibits the proteasomal degradation of homocysteine-induced endoplasmic reticulum protein

International Nuclear Information System (INIS)

Maeda, Tomoji; Tanabe-Fujimura, Chiaki; Fujita, Yu; Abe, Chihiro; Nanakida, Yoshino; Zou, Kun; Liu, Junjun; Liu, Shuyu; Nakajima, Toshihiro; Komano, Hiroto

2016-01-01

Homocysteine-induced endoplasmic reticulum (ER) protein (Herp) is an ER stress-inducible key regulatory component of ER-associated degradation (ERAD) that has been implicated in insulin hypersecretion in diabetic mouse models. Herp expression is tightly regulated. Additionally, Herp is a highly labile protein and interacts with various proteins, which are characteristic features of ubiquitinated protein. Previously, we reported that ubiquitination is not required for Herp degradation. In addition, we found that the lysine residues of Herp (which are ubiquitinated by E3 ubiquitin ligase) are not sufficient for regulation of Herp degradation. In this study, we found that NAD(P)H quinone oxidoreductase 1 (NQO1)-mediated targeting of Herp to the proteasome was involved in Herp degradation. In addition, we found that Herp protein levels were markedly elevated in synoviolin-null cells. The E3 ubiquitin ligase synoviolin is a central component of ERAD and is involved in the degradation of nuclear factor E2-related factor-2 (Nrf2), which regulates cellular reactive oxygen species. Additionally, NQO1 is a target of Nrf2. Thus, our findings indicated that NQO1 could stabilize Herp protein expression via indirect regulation of synoviolin. -- Highlights: •Herp interacts with NQO1. •NQO1 regulates Herp degradation.

Culture-bound syndromes in Hispanic primary care patients.

Science.gov (United States)

Bayles, Bryan P; Katerndahl, David A

2009-01-01

We sought to document Hispanic primary care patients' knowledge and experience of five culture-bound syndromes (CBS), as well as the basic socio-cultural correlates of these disorders. A convenience sample of 100 adult Hispanic patients presenting in an urban South Texas primary care clinic was recruited to complete a brief cross-sectional survey, presented in an oral format. Interviews sought information concerning five culture-bound syndromes--susto, empacho, nervios, mal de ojo, and ataques de nervios. Additional demographic, socio-economic, and acculturation data was collected. Descriptive and bivariate statistics (chi square, Fisher's) were used to assess relationships among variables and experience with each CBS. A multivariate logistic analysis was conducted to determine the possible contributions of age, gender, acculturation, and education to the personal experience of a culture-bound syndrome. Results indicate that 77% of respondents had knowledge of all five syndromes, with 42% reporting having personally experienced at least one CBS. Nervios was the most commonly suffered disorder, being reported by 30 respondents. This was followed, in declining order ofprevalence, by susto, mal de ojo, empacho, and ataques de nervios. Multivariate logistic regression analysis found that higher education beyond high school was associated with a slightly decreased likelihood of reporting having suffered from any culture-bound syndrome. While co-occurrence among these disorders occurred, the patterns of predictors suggest that the co-occurrence is not a reflection of mislabeling of one common syndrome. Knowledge of and experience with culture-bound syndromes is common among Hispanic primary care patients in South Texas. Healthcare providers ought to consider discussing these illnesses in a non-judgmental manner with patients who present with symptoms that are consistent with these syndromes. Future studies, with larger sample sizes, are warranted to elucidate the nature

Bounds of Certain Dynamic Inequalities on Time Scales

Directory of Open Access Journals (Sweden)

Deepak B. Pachpatte

2014-10-01

Full Text Available In this paper we study explicit bounds of certain dynamic integral inequalities on time scales. These estimates give the bounds on unknown functions which can be used in studying the qualitative aspects of certain dynamic equations. Using these inequalities we prove the uniqueness of some partial integro-differential equations on time scales.

Bounds and enhancements for negative scattering time delays

International Nuclear Information System (INIS)

Muga, J.G.; Egusquiza, I.L.; Damborenea, J.A.; Delgado, F.

2002-01-01

The time of passage of the transmitted wave packet in a tunneling collision of a quantum particle with a square potential barrier becomes independent of the barrier width in a range of barrier thickness. This is the Hartman effect, which has been frequently associated with 'superluminality'. A fundamental limitation on the effect is set by nonrelativistic 'causality conditions'. We demonstrate first that the causality conditions impose more restrictive bounds on the negative time delays (time advancements) when no bound states are present. These restrictive bounds are in agreement with a naive, and generally false, causality argument based on the positivity of the 'extrapolated phase time', one of the quantities proposed to characterize the duration of the barrier's traversal. Nevertheless, square wells may in fact lead to much larger advancements than square barriers. We point out that close to the thresholds of new bound states, the time advancement increases considerably, while, at the same time, the transmission probability is large, which facilitates the possible observation of the enhanced time advancement

Two-nucleon bound states in quenched lattice QCD

International Nuclear Information System (INIS)

Yamazaki, T.; Kuramashi, Y.; Ukawa, A.

2011-01-01

We address the issue of bound state in the two-nucleon system in lattice QCD. Our study is made in the quenched approximation at the lattice spacing of a=0.128 fm with a heavy quark mass corresponding to m π =0.8 GeV. To distinguish a bound state from an attractive scattering state, we investigate the volume dependence of the energy difference between the ground state and the free two-nucleon state by changing the spatial extent of the lattice from 3.1 fm to 12.3 fm. A finite energy difference left in the infinite spatial volume limit leads us to the conclusion that the measured ground states for not only spin triplet but also singlet channels are bounded. Furthermore the existence of the bound state is confirmed by investigating the properties of the energy for the first excited state obtained by a 2x2 diagonalization method. The scattering lengths for both channels are evaluated by applying the finite volume formula derived by Luescher to the energy of the first excited states.

Variation of glucosinolates and quinone reductase activity among different varieties of Chinese kale and improvement of glucoraphanin by metabolic engineering.

Science.gov (United States)

Qian, Hongmei; Sun, Bo; Miao, Huiying; Cai, Congxi; Xu, Chaojiong; Wang, Qiaomei

2015-02-01

The variation of glucosinolates and quinone reductase (QR) activity in fourteen varieties of Chinese kale (Brassica oleracea var. alboglabra Bailey) was investigated in the present study. Results showed that gluconapin (GNA), instead of glucoraphanin (GRA), was the most predominant glucosinolate in all varieties, and QR activity was remarkably positively correlated with the glucoraphanin level. AOP2, a tandem 2-oxoglutarate-dependent dioxygenase, catalyzes the conversion of glucoraphanin to gluconapin in glucosinolate biosynthesis. Here, antisense AOP2 was transformed into Gailan-04, the variety with the highest gluconapin content and ratio of GNA/GRA. The glucoraphanin content and corresponding QR activity were notably increased in transgenic plants, while no significant difference at the level of other main nutritional compounds (total phenolics, vitamin C, carotenoids and chlorophyll) was observed between the transgenic lines and the wide-type plants. Taken together, metabolic engineering is a good practice for improvement of glucoraphanin in Chinese kale. Copyright © 2014 Elsevier Ltd. All rights reserved.

Output controllability of nonlinear systems with bounded control

International Nuclear Information System (INIS)

Garcia, Rafael; D'Attellis, Carlos

1990-01-01

The control problem treated in this paper is the output controllability of a nonlinear system in the form: x = f(x) + g(x)u(t); y = h(x), using bounded controls. The approach to the problem consists of a modification in the system using dynamic feedback in such a way that the input/output behaviour of the closed loop matches the input/output behaviour of a completely output-controllable system with bounded controls. Sufficient conditions are also put forward on the system so that a compact set in the output space may be reached in finite time using uniformally bounded controls, and a result on output regulation in finite time with asymptotic state stabilization is obtained. (Author)

Malabsorption of protein bound vitamin B12.

OpenAIRE

Dawson, D W; Sawers, A H; Sharma, R K

1984-01-01

Patients with subnormal serum vitamin B12 concentrations were tested for absorption of protein bound vitamin B12 and compared with controls. Absorption of the protein bound vitamin appeared to decrease with increasing age in healthy subjects. Differences between the result of this test and the result of the Schilling test in patients who had undergone gastric surgery were confirmed; such differences were also seen in some patients who had iron deficiency anaemia, an excessive alcohol intake, ...

New Spectral Features from Bound Dark Matter

DEFF Research Database (Denmark)

Catena, Riccardo; Kouvaris, Chris

2016-01-01

We demonstrate that dark matter particles gravitationally bound to the Earth can induce a characteristic nuclear recoil signal at low energies in direct detection experiments. The new spectral feature we predict can provide the ultimate smoking gun for dark matter discovery for experiments...... with positive signal but unclear background. The new feature is universal, in that the ratio of bound over halo dark matter event rates at detectors is independent of the dark matter-nucleon cross section....

On functions of bounded semivariation

Czech Academy of Sciences Publication Activity Database

Monteiro, Giselle Antunes

2015-01-01

Roč. 40, č. 2 (2015), s. 233-276 ISSN 0147-1937 Institutional support: RVO:67985840 Keywords : semivariation * functions of bounded variation * regulated functions Subject RIV: BA - General Mathematics http://projecteuclid.org/euclid.rae/1491271216

Faddeev-Yakubovsky technique for weakly bound systems

International Nuclear Information System (INIS)

Hadizadeh, M.R.; Yamashita, M.T.; Tomio, Lauro; Delfino, A.

2011-01-01

Nature shows the existence of weakly bound systems in different sectors, ranging from atomic to nuclear physics. Few-body systems with large scattering length exhibit universal features, which are independent of the details of the interaction, and thus are common to nuclear and atomic systems. Very different methods are used to study the properties of few-body systems, from Faddeev methods to diagonalization methods that rely on an expansion of the wave functions in a complete basis set, like e.g. hyper-spherical harmonics and no core shell model. In this talk we present Faddeev-Yakubovsky method to study the three- and four-body bound states in momentum space. To show the efficiency and accuracy of the method we investigate the three- and four-boson weakly bound states in unitary limit (for zero two-body binding) and we present a pretty complete picture of universality. (author)

Bound values for Hall conductivity of heterogeneous medium under ...

Indian Academy of Sciences (India)

- ditions in inhomogeneous medium has been studied. It is shown that bound values for. Hall conductivity differ from bound values for metallic conductivity. This is due to the unusual character of current percolation under quantum Hall effect ...

Lower Bounds for Number-in-Hand Multiparty Communication Complexity, Made Easy

DEFF Research Database (Denmark)

Phillips, Jeff; Verbin, Elad; Zhang, Qin

2012-01-01

; the technique seems applicable to a wide range of other problems as well. The obtained communication lower bounds imply new lower bounds in the functional monitoring model [11] (also called the distributed streaming model). All of our lower bounds allow randomized communication protocols with two-sided error......In this paper we prove lower bounds on randomized multiparty communication complexity, both in the blackboard model (where each message is written on a blackboard for all players to see) and (mainly) in the message-passing model, where messages are sent player-to-player. We introduce a new...... technique for proving such bounds, called symmetrization, which is natural, intuitive, and often easy to use. For example, for the problem where each of k players gets a bit-vector of length n, and the goal is to compute the coordinate-wise XOR of these vectors, we prove a tight lower bounds of Ω...

Reply to ''Limitation on numerical bounds on transition probabilities''

International Nuclear Information System (INIS)

Storm, D.

1975-01-01

It is demonstrated that a good share of the error Shakeshaft attributes to the failure to account for ionization in customary impact-parameter calculations for proton--hydrogen-atom scattering amplitudes really results from the inadequacy of the traveling hydrogenic basis set to account for the dynamic polarization of the hydrogen atom by the moving proton. The lower limit for the first-order bound can be reduced by using hydrogenlike basis functions that allow for this polarization. Bounds on the cross sections obtained by using the bound Δ 1 need not be infinite. The inclusion of time-dependent adjustable parameters in the basis functions provides a method for modifying the projection of the deviation vector or error term in the Schroedinger equation in the continuum. The exploratory work of Storm and Rapp appears to offer hope that reasonably accurate bounds on at least the 1s charge-exchange amplitudes and cross sections can be obtained by employing only square-integrable basis functions that contain time-dependent variable parameters. However, if it is necessary to account for the flux in the ionization channels, it is shown that an account could be made without the bound becoming infinite

Upper bounds on the number of errors corrected by a convolutional code

DEFF Research Database (Denmark)

Justesen, Jørn

2004-01-01

We derive upper bounds on the weights of error patterns that can be corrected by a convolutional code with given parameters, or equivalently we give bounds on the code rate for a given set of error patterns. The bounds parallel the Hamming bound for block codes by relating the number of error...

Do the Uncertainty Relations Really have Crucial Significances for Physics?

Directory of Open Access Journals (Sweden)

Dumitru S.

2010-10-01

Full Text Available It is proved the falsity of idea that the Uncertainty Relations (UR have crucial significances for physics. Additionally one argues for the necesity of an UR-disconnected quantum philosophy.

Relativistic bound states: a mass formula for vector mesons

International Nuclear Information System (INIS)

Richard, J.L.; Sorba, P.

1975-07-01

In the framework of a relativistic description of two particles bound states, a mass formula for vector mesons considered as quark-antiquark systems bound by harmonic oscillator like forces is proposed. Results in good agreement with experimental values are obtained [fr

An upper bound on the number of independent sets in a tree

DEFF Research Database (Denmark)

Pedersen, Anders Sune

2007-01-01

The main result of this paper is an upper bound on the number of independent sets in a tree in terms of the order and diameter of the tree. This new upper bound is a refinement of the bound given by Prodinger and Tichy [ Fibonacci Q., 20 (1982), no. 1, 16-21]. Finally, we give a sufficient...... condition for the new upper bound to be better thatn the upper bound given by Brigham, Chandrasekharan and Dutton [ Fibonacci Q., 31 (1993), no. 2, 98-104]....

An upper bound on the number of independent sets in a tree

DEFF Research Database (Denmark)

Vestergaard, Preben Dahl; Pedersen, Anders Sune

The main result of this paper is an upper bound on the number of independent sets in a tree in terms of the order and diameter of the tree. This new upper bound is a refinement of the bound given by Prodinger and Tichy [Fibonacci Q., 20 (1982), no. 1, 16-21]. Finally, we give a sufficient condition...... for the new upper bound to be better than the upper bound given by Brigham, Chandrasekharan and Dutton [Fibonacci Q., 31 (1993), no. 2, 98-104]....

[Membrane-bound cytokine and feedforward regulation].

Science.gov (United States)

Wu, Ke-Fu; Zheng, Guo-Guang; Ma, Xiao-Tong; Song, Yu-Hua

2013-10-01

Feedback and feedforward widely exist in life system, both of them are the basic processes of control system. While the concept of feedback has been widely used in life science, feedforward regulation was systematically studied in neurophysiology, awaiting further evidence and mechanism in molecular biology and cell biology. The authors put forward a hypothesis about the feedforward regulation of membrane bound macrophage colony stimulation factor (mM-CSF) on the basis of their previous work. This hypothesis might provide a new direction for the study on the biological effects of mM-CSF on leukemia and solid tumors, and contribute to the study on other membrane bound cytokines.

Finding Maximal Pairs with Bounded Gap

DEFF Research Database (Denmark)

Brodal, Gerth Stølting; Lyngsø, Rune B.; Pedersen, Christian N. S.

1999-01-01

. In this paper we present methods for finding all maximal pairs under various constraints on the gap. In a string of length n we can find all maximal pairs with gap in an upper and lower bounded interval in time O(n log n+z) where z is the number of reported pairs. If the upper bound is removed the time reduces...... to O(n+z). Since a tandem repeat is a pair where the gap is zero, our methods can be seen as a generalization of finding tandem repeats. The running time of our methods equals the running time of well known methods for finding tandem repeats....

Whole cell Deinococcus radiodurans ameliorates salt stress in Indian mustard through pyrroloquinoline quinone

International Nuclear Information System (INIS)

Srivastava, A.K.; Jadhav, P.; Suprasanna, P.; Rajpurohit, Y.S.; Misra, H.S.

2015-01-01

Salinity stress is considered as one of the major abiotic stresses limiting crop productivity. A variety of symbiotic and non-symbiotic bacteria are currently being used worldwide with the aim to boost built-in defense system in plants. Deinococcus radiodurans is a highly desiccation and radiation tolerant bacterium which synthesizes PQQ (pyrroloquinoline quinone) that has been shown to have a versatile role in crop productivity and as a general stress response regulator in bacteria and mammals. PQQ also acts as scavenger of reactive oxygen species and hence, can module redox signaling, one of the major regulator of stress tolerance in plants. In view of this, present research was conducted to evaluate the potential of whole cell D. radiodurans for ameliorating salt stress in plants. The soil colonization with wild-type cells led to partial amelioration of salt stress. The PQQ mutant showed an intermediate phenotype between wild-type seedlings and those grown on non-colonized soils which confirmed that the effects are largely associated with PQQ. The differential phenotype was also correlated with ROS level and ABA accumulation. The flame photometry data showed that there was no significant reduction in water soluble Na + level in control plant and those treated with either wild-type or PQQ mutant. Further, the elevated levels of antioxidant enzymes and reduced ascorbate in the plants treated with bacterial cells indicated its positive role in oxidative stress management. Although, the exact molecular basis to these effects is yet to be understood, present findings support the use of whole cell D. radiodurans for managing the growth and productivity of Indian mustard in salt affected fields. (author)

Extrinsic Isoperimetric Analysis on Submanifolds with Curvatures bounded from below

DEFF Research Database (Denmark)

Markvorsen, Steen; Palmer, Vicente

2010-01-01

and on the radial part of the intrinsic unit normals at the boundaries of the extrinsic spheres, respectively. In the same vein we also establish lower bounds on the mean exit time for Brownian motions in the extrinsic balls, i.e. lower bounds for the time it takes (on average) for Brownian particles to diffuse......We obtain upper bounds for the isoperimetric quotients of extrinsic balls of submanifolds in ambient spaces which have a lower bound on their radial sectional curvatures. The submanifolds are themselves only assumed to have lower bounds on the radial part of the mean curvature vector field...... within the extrinsic ball from a given starting point before they hit the boundary of the extrinsic ball. In those cases, where we may extend our analysis to hold all the way to infinity, we apply a capacity comparison technique to obtain a sufficient condition for the submanifolds to be parabolic, i...

Membrane-based ethylene/ethane separation: The upper bound and beyond

KAUST Repository

Rungta, Meha

2013-08-02

Ethylene/ethane separation via cryogenic distillation is extremely energy-intensive, and membrane separation may provide an attractive alternative. In this paper, ethylene/ethane separation performance using polymeric membranes is summarized, and an experimental ethylene/ethane polymeric upper bound based on literature data is presented. A theoretical prediction of the ethylene/ethane upper bound is also presented, and shows good agreement with the experimental upper bound. Further, two ways to overcome the ethylene/ethane upper bound, based on increasing the sorption or diffusion selectivity, is also discussed, and a review on advanced membrane types such as facilitated transport membranes, zeolite and metal organic framework based membranes, and carbon molecular sieve membranes is presented. Of these, carbon membranes have shown the potential to surpass the polymeric ethylene/ethane upper bound performance. Furthermore, a convenient, potentially scalable method for tailoring the performance of carbon membranes for ethylene/ethane separation based on tuning the pyrolysis conditions has also been demonstrated. © 2013 American Institute of Chemical Engineers.

Adaptive information-theoretic bounded rational decision-making with parametric priors

OpenAIRE

Grau-Moya, Jordi; Braun, Daniel A.

2015-01-01

Deviations from rational decision-making due to limited computational resources have been studied in the field of bounded rationality, originally proposed by Herbert Simon. There have been a number of different approaches to model bounded rationality ranging from optimality principles to heuristics. Here we take an information-theoretic approach to bounded rationality, where information-processing costs are measured by the relative entropy between a posterior decision strategy and a given fix...

A lower bound on the mass of dark matter particles

International Nuclear Information System (INIS)

Boyarsky, Alexey; Ruchayskiy, Oleg; Iakubovskyi, Dmytro

2009-01-01

We discuss the bounds on the mass of Dark Matter (DM) particles, coming from the analysis of DM phase-space distribution in dwarf spheroidal galaxies (dSphs). After reviewing the existing approaches, we choose two methods to derive such a bound. The first one depends on the information about the current phase space distribution of DM particles only, while the second one uses both the initial and final distributions. We discuss the recent data on dSphs as well as astronomical uncertainties in relevant parameters. As an application, we present lower bounds on the mass of DM particles, coming from various dSphs, using both methods. The model-independent bound holds for any type of fermionic DM. Stronger, model-dependent bounds are quoted for several DM models (thermal relics, non-resonantly and resonantly produced sterile neutrinos, etc.). The latter bounds rely on the assumption that baryonic feedback cannot significantly increase the maximum of a distribution function of DM particles. For the scenario in which all the DM is made of sterile neutrinos produced via non-resonant mixing with the active neutrinos (NRP) this gives m NRP > 1.7 keV. Combining these results in their most conservative form with the X-ray bounds of DM decay lines, we conclude that the NRP scenario remains allowed in a very narrow parameter window only. This conclusion is independent of the results of the Lyman-α analysis. The DM model in which sterile neutrinos are resonantly produced in the presence of lepton asymmetry remains viable. Within the minimal neutrino extension of the Standard Model (the νMSM), both mass and the mixing angle of the DM sterile neutrino are bounded from above and below, which suggests the possibility for its experimental search

Upper bounds on the entropy of radiation systems

Institute of Scientific and Technical Information of China (English)

汪定雄

1997-01-01

The upper bounds on the entropy of a radiation system confined to a spherical box are calculated in six cases by using the equation of state of radiation in flat spacetime and the equation of state of radiation near black-hole horizon,which was derived by Li and Liu (hereafter the Li-Liu equation).It turns out that the Li-Liu equation does have unique advantage in dealing with the entropy bound of critical self-gravitating radiation systems,while the usual equation of state will result in entropy divergence.In the case of non-self-gravitating radiation systems and non-critical self-gravitating radiation systems,there is no difference in the entropy bounds derived by these two equations of state.

Bounds for the propagation speed of combustion flames

International Nuclear Information System (INIS)

Fort, Joaquim; Campos, Daniel; Gonzalez, Josep R; Velayos, Joaquim

2004-01-01

We focus on a combustion model for premixed flames based on two coupled equations determining the spatial dynamics of temperature and fuel density. We rewrite these equations as a classical reaction-diffusion model, so that we can apply some known methods for the prediction of lower and upper bounds to the front speed. The predictions are compared to simulations, which show that our new bounds substantially improve those following from the linearization method, used in the previous work of Fort et al (2000 J. Phys. A: Math. Gen. 33 6953). Radiative losses lead to pulses rather than fronts. We find a bound for their speed which (in contrast to the linearization one) correctly predicts the order of magnitude of the flame speed

Research on Bounded Rationality of Fuzzy Choice Functions

Directory of Open Access Journals (Sweden)

Xinlin Wu

2014-01-01

Full Text Available The rationality of a fuzzy choice function is a hot research topic in the study of fuzzy choice functions. In this paper, two common fuzzy sets are studied and analyzed in the framework of the Banerjee choice function. The complete rationality and bounded rationality of fuzzy choice functions are defined based on the two fuzzy sets. An assumption is presented to study the fuzzy choice function, and especially the fuzzy choice function with bounded rationality is studied combined with some rationality conditions. Results show that the fuzzy choice function with bounded rationality also satisfies some important rationality conditions, but not vice versa. The research gives supplements to the investigation in the framework of the Banerjee choice function.

Bounds for the propagation speed of combustion flames

Energy Technology Data Exchange (ETDEWEB)

Fort, Joaquim [Departament de FIsica, Universitat de Girona, Campus de Montilivi, 17071 Girona, Catalonia (Spain); Campos, Daniel [Grup de FIsica EstadIstica, Departament de FIsica, Universitat Autonoma de Barcelona, E-08193 Bellaterra (Spain); Gonzalez, Josep R [Grup de Mecanica de Fluids, Departament d' Enginyeria Mecanica, Universitat de Girona, Campus de Montilivi, 17071 Girona, Catalonia (Spain); Velayos, Joaquim [Grup de Mecanica de Fluids, Departament d' Enginyeria Mecanica, Universitat de Girona, Campus de Montilivi, 17071 Girona, Catalonia (Spain)

2004-07-23

We focus on a combustion model for premixed flames based on two coupled equations determining the spatial dynamics of temperature and fuel density. We rewrite these equations as a classical reaction-diffusion model, so that we can apply some known methods for the prediction of lower and upper bounds to the front speed. The predictions are compared to simulations, which show that our new bounds substantially improve those following from the linearization method, used in the previous work of Fort et al (2000 J. Phys. A: Math. Gen. 33 6953). Radiative losses lead to pulses rather than fronts. We find a bound for their speed which (in contrast to the linearization one) correctly predicts the order of magnitude of the flame speed.

Determining Bounds on Assumption Errors in Operational Analysis

Directory of Open Access Journals (Sweden)

Neal M. Bengtson

2014-01-01

Full Text Available The technique of operational analysis (OA is used in the study of systems performance, mainly for estimating mean values of various measures of interest, such as, number of jobs at a device and response times. The basic principles of operational analysis allow errors in assumptions to be quantified over a time period. The assumptions which are used to derive the operational analysis relationships are studied. Using Karush-Kuhn-Tucker (KKT conditions bounds on error measures of these OA relationships are found. Examples of these bounds are used for representative performance measures to show limits on the difference between true performance values and those estimated by operational analysis relationships. A technique for finding tolerance limits on the bounds is demonstrated with a simulation example.

Evidence for a bound on the lifetime of de Sitter space

International Nuclear Information System (INIS)

Freivogel, Ben; Lippert, Matthew

2008-01-01

Recent work has suggested a surprising new upper bound on the lifetime of de Sitter vacua in string theory. The bound is parametrically longer than the Hubble time but parametrically shorter than the recurrence time. We investigate whether the bound is satisfied in a particular class of de Sitter solutions, the KKLT vacua. Despite the freedom to make the supersymmetry breaking scale exponentially small, which naively would lead to extremely stable vacua, we find that the lifetime is always less than about exp(10 22 ) Hubble times, in agreement with the proposed bound. This result, however, is contingent on several estimates and assumptions; in particular, we rely on a conjectural upper bound on the Euler number of the Calabi-Yau fourfolds used in KKLT compactifications.

Computational experience with a parallel algorithm for tetrangle inequality bound smoothing.

Science.gov (United States)

Rajan, K; Deo, N

1999-09-01

Determining molecular structure from interatomic distances is an important and challenging problem. Given a molecule with n atoms, lower and upper bounds on interatomic distances can usually be obtained only for a small subset of the 2(n(n-1)) atom pairs, using NMR. Given the bounds so obtained on the distances between some of the atom pairs, it is often useful to compute tighter bounds on all the 2(n(n-1)) pairwise distances. This process is referred to as bound smoothing. The initial lower and upper bounds for the pairwise distances not measured are usually assumed to be 0 and infinity. One method for bound smoothing is to use the limits imposed by the triangle inequality. The distance bounds so obtained can often be tightened further by applying the tetrangle inequality--the limits imposed on the six pairwise distances among a set of four atoms (instead of three for the triangle inequalities). The tetrangle inequality is expressed by the Cayley-Menger determinants. For every quadruple of atoms, each pass of the tetrangle inequality bound smoothing procedure finds upper and lower limits on each of the six distances in the quadruple. Applying the tetrangle inequalities to each of the (4n) quadruples requires O(n4) time. Here, we propose a parallel algorithm for bound smoothing employing the tetrangle inequality. Each pass of our algorithm requires O(n3 log n) time on a REW PRAM (Concurrent Read Exclusive Write Parallel Random Access Machine) with O(log(n)n) processors. An implementation of this parallel algorithm on the Intel Paragon XP/S and its performance are also discussed.

Computational Lower Bounds Using Diagonalization

Indian Academy of Sciences (India)

Home; Journals; Resonance – Journal of Science Education; Volume 14; Issue 7. Computational Lower Bounds Using Diagonalization - Languages, Turing Machines and Complexity Classes. M V Panduranga Rao. General Article Volume 14 Issue 7 July 2009 pp 682-690 ...

Self-bound droplets of a dilute magnetic quantum liquid

Science.gov (United States)

Schmitt, Matthias; Wenzel, Matthias; Böttcher, Fabian; Ferrier-Barbut, Igor; Pfau, Tilman

2016-11-01

Self-bound many-body systems are formed through a balance of attractive and repulsive forces and occur in many physical scenarios. Liquid droplets are an example of a self-bound system, formed by a balance of the mutual attractive and repulsive forces that derive from different components of the inter-particle potential. It has been suggested that self-bound ensembles of ultracold atoms should exist for atom number densities that are 108 times lower than in a helium droplet, which is formed from a dense quantum liquid. However, such ensembles have been elusive up to now because they require forces other than the usual zero-range contact interaction, which is either attractive or repulsive but never both. On the basis of the recent finding that an unstable bosonic dipolar gas can be stabilized by a repulsive many-body term, it was predicted that three-dimensional self-bound quantum droplets of magnetic atoms should exist. Here we report the observation of such droplets in a trap-free levitation field. We find that this dilute magnetic quantum liquid requires a minimum, critical number of atoms, below which the liquid evaporates into an expanding gas as a result of the quantum pressure of the individual constituents. Consequently, around this critical atom number we observe an interaction-driven phase transition between a gas and a self-bound liquid in the quantum degenerate regime with ultracold atoms. These droplets are the dilute counterpart of strongly correlated self-bound systems such as atomic nuclei and helium droplets.

A tail bound for read-k families of functions

Czech Academy of Sciences Publication Activity Database

Gavinsky, Dmitry; Lovett, S.; Saks, M.; Srinivasan, S.

2015-01-01

Roč. 47, č. 1 (2015), s. 99-108 ISSN 1042-9832 Institutional support: RVO:67985840 Keywords : tail bound * deviation bound * random variables Subject RIV: BA - General Mathematics Impact factor: 1.011, year: 2015 http://onlinelibrary.wiley.com/doi/10.1002/ rsa .20532/abstract

A tail bound for read-k families of functions

Czech Academy of Sciences Publication Activity Database

Gavinsky, Dmitry; Lovett, S.; Saks, M.; Srinivasan, S.

2015-01-01

Roč. 47, č. 1 (2015), s. 99-108 ISSN 1042-9832 Institutional support: RVO:67985840 Keywords : tail bound * deviation bound * random variables Subject RIV: BA - General Mathematics Impact factor: 1.011, year: 2015 http://onlinelibrary.wiley.com/doi/10.1002/rsa.20532/abstract

John Lilly, The Mind of the Dolphin, and Communication Out of Bounds

Directory of Open Access Journals (Sweden)

Bruce Clarke

2014-09-01

Full Text Available In this essay I develop a systems-theoretical observation of John Lilly’s cybernetics of communication in his 1967 work The Mind of the Dolphin. The eight-year-old project that The Mind of the Dolphin recounts for public consumption details his aspiration to achieve an unprecedented breakthrough beyond companionate communion to fully abstract linguistic communication across species boundaries. Between 1959 and 1968 Lilly wagered and lost his mainstream scientific career largely over this audacious, ultimately inconclusive bid to establish and document for scientific validation “communication with a nonhuman mind.” In that effort, however, he mobilized the best available tools, a cutting-edge array of cybernetic concepts. He leaned heavily on the information theory bound up with first-order cybernetics and operated with heuristic computational metaphors alongside the actual computers of his era. As I will elicit through some close readings of his texts, in that process Lilly also homed in on crucial epistemological renovations with a constructivist redescription of cognition that may have influenced and motivated his colleague Heinz von Foerster’s more renowned formulations, arriving in the early 1970s, of a second-order cybernetics.

A note on BPS vortex bound states

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A. Alonso-Izquierdo

2016-02-01

Full Text Available In this note we investigate bound states, where scalar and vector bosons are trapped by BPS vortices in the Abelian Higgs model with a critical ratio of the couplings. A class of internal modes of fluctuation around cylindrically symmetric BPS vortices is characterized mathematically, analyzing the spectrum of the second-order fluctuation operator when the Higgs and vector boson masses are equal. A few of these bound states with low values of quantized magnetic flux are described fully, and their main properties are discussed.

A note on BPS vortex bound states

Energy Technology Data Exchange (ETDEWEB)

Alonso-Izquierdo, A., E-mail: alonsoiz@usal.es [Departamento de Matematica Aplicada, Universidad de Salamanca (Spain); Garcia Fuertes, W., E-mail: wifredo@uniovi.es [Departamento de Fisica, Universidad de Oviedo (Spain); Mateos Guilarte, J., E-mail: guilarte@usal.es [Departamento de Fisica Fundamental, Universidad de Salamanca (Spain)

2016-02-10

In this note we investigate bound states, where scalar and vector bosons are trapped by BPS vortices in the Abelian Higgs model with a critical ratio of the couplings. A class of internal modes of fluctuation around cylindrically symmetric BPS vortices is characterized mathematically, analyzing the spectrum of the second-order fluctuation operator when the Higgs and vector boson masses are equal. A few of these bound states with low values of quantized magnetic flux are described fully, and their main properties are discussed.

Relativistic bound-state problem of a one-dimensional system

International Nuclear Information System (INIS)

Sato, T.; Niwa, T.; Ohtsubo, H.; Tamura, K.

1991-01-01

A Poincare-covariant description of the two-body bound-state problem in one-dimensional space is studied by using the relativistic Schrodinger equation. We derive the many-body Hamiltonian, electromagnetic current and generators of the Poincare group in the framework of one-boson exchange. Our theory satisfies Poincare algebra within the one-boson-exchange approximation. We numerically study the relativistic effects on the bound-state wavefunction and the elastic electromagnetic form factor. The Lorentz boost of the bound-state wavefunction and the two-body exchange current are shown to play an important role in guaranteeing the Lorentz invariance of the form factor. (author)

Upper bound on the radii of black-hole photonspheres

International Nuclear Information System (INIS)

Hod, Shahar

2013-01-01

One of the most remarkable predictions of the general theory of relativity is the existence of black-hole “photonspheres”, compact null hypersurfaces on which massless particles can orbit the central black hole. We prove that every spherically-symmetric asymptotically flat black-hole spacetime is characterized by a photonsphere whose radius is bounded from above by r γ ⩽3M, where M is the total ADM mass of the black-hole spacetime. It is shown that hairy black-hole configurations conform to this upper bound. In particular, the null circular geodesic of the (bald) Schwarzschild black-hole spacetime saturates the bound

Upper bounds on minimum cardinality of exact and approximate reducts

KAUST Repository

Chikalov, Igor

2010-01-01

In the paper, we consider the notions of exact and approximate decision reducts for binary decision tables. We present upper bounds on minimum cardinality of exact and approximate reducts depending on the number of rows (objects) in the decision table. We show that the bound for exact reducts is unimprovable in the general case, and the bound for approximate reducts is almost unimprovable in the general case. © 2010 Springer-Verlag Berlin Heidelberg.

Bionic Control of Cheetah Bounding with a Segmented Spine.

Science.gov (United States)

Wang, Chunlei; Wang, Shigang

2016-01-01

A cheetah model is built to mimic real cheetah and its mechanical and dimensional parameters are derived from the real cheetah. In particular, two joints in spine and four joints in a leg are used to realize the motion of segmented spine and segmented legs which are the key properties of the cheetah bounding. For actuating and stabilizing the bounding gait of cheetah, we present a bioinspired controller based on the state-machine. The controller mainly mimics the function of the cerebellum to plan the locomotion and keep the body balance. The haptic sensor and proprioception system are used to detect the trigger of the phase transition. Besides, the vestibular modulation could perceive the pitching angle of the trunk. At last, the cerebellum acts as the CPU to operate the information from the biological sensors. In addition, the calculated results are transmitted to the low-level controller to actuate and stabilize the cheetah bounding. Moreover, the delay feedback control method is employed to plan the motion of the leg joints to stabilize the pitching motion of trunk with the stability criterion. Finally, the cyclic cheetah bounding with biological properties is realized. Meanwhile, the stability and dynamic properties of the cheetah bounding gait are analyzed elaborately.

Bionic Control of Cheetah Bounding with a Segmented Spine

Directory of Open Access Journals (Sweden)

Chunlei Wang

2016-01-01

Full Text Available A cheetah model is built to mimic real cheetah and its mechanical and dimensional parameters are derived from the real cheetah. In particular, two joints in spine and four joints in a leg are used to realize the motion of segmented spine and segmented legs which are the key properties of the cheetah bounding. For actuating and stabilizing the bounding gait of cheetah, we present a bioinspired controller based on the state-machine. The controller mainly mimics the function of the cerebellum to plan the locomotion and keep the body balance. The haptic sensor and proprioception system are used to detect the trigger of the phase transition. Besides, the vestibular modulation could perceive the pitching angle of the trunk. At last, the cerebellum acts as the CPU to operate the information from the biological sensors. In addition, the calculated results are transmitted to the low-level controller to actuate and stabilize the cheetah bounding. Moreover, the delay feedback control method is employed to plan the motion of the leg joints to stabilize the pitching motion of trunk with the stability criterion. Finally, the cyclic cheetah bounding with biological properties is realized. Meanwhile, the stability and dynamic properties of the cheetah bounding gait are analyzed elaborately.

Positivity bounds for Sivers functions

International Nuclear Information System (INIS)

Kang Zhongbo; Soffer, Jacques

2011-01-01

We generalize a positivity constraint derived initially for parity-conserving processes to the parity-violating ones, and use it to derive non-trivial bounds on several Sivers functions, entering in the theoretical description of single spin asymmetry for various processes.

Stiffness-dependent cellular internalization of matrix-bound BMP-2 and its relation to Smad and non-Smad signaling.

Science.gov (United States)

Gilde, Flora; Fourel, Laure; Guillot, Raphael; Pignot-Paintrand, Isabelle; Okada, Takaharu; Fitzpatrick, Vincent; Boudou, Thomas; Albiges-Rizo, Corinne; Picart, Catherine

2016-12-01

factors by a biomaterial will open new perspectives for regenerative medicine. However, to date, very little is known about how matrix-bound growth factors are delivered to cells, especially whether they are internalized and how they are signaling to drive key differentiation events. These initial steps are crucial as they will guide the subsequent processes leading to tissue regeneration. In this work, we investigate the uptake and processing by cells of BMP-2 ligands embedded in polyelectrolyte multilayer films in comparison to soluble BMP-2. We show that BMP-2 responsive cells can internalize matrix-bound BMP-2 and that internalization is dependent on the cross-linking level of the polyelectrolyte films. In addition, we show that internalization is mediated by both clathrin- and caveolin-dependent pathways. While inhibiting clathrin-dependent endocytosis affects only non-canonical signaling, blocking caveolin-1-dependent endocytosis reduces both canonical and non-canonical BMP signaling. The signaling pathways found for matrix-bound BMP-2 are similar to those found for soluble BMP-2. These results highlight that BMP-2 presented by a biomaterial at the ventral side of the cell can trigger major endocytic and associated signaling pathways leading to bone regeneration. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Culture-Bound Words of the Danube Basin Countries: Translation into English

Directory of Open Access Journals (Sweden)

Chetverikova Olena

2015-08-01

Full Text Available Any course in linguistic country study or popular text translation is impossible without adequate understanding and presentation of culture-bound elements, which present one of the most difficult topics to deal with, especially in multicultural countries. Our investigation aims to show the problems, which appear when we deal with equivalent-lacking words related to culture. Sometimes equivalent-lacking words are associated with culture-bound words, the Ukrainian equivalent for them is “реалії” (derived from Latin realis, pl. realia. However, the term “culture-bound word” is of narrower meaning than the term “equivalent-lacking word”. A culture-bound word names an object peculiar to this or that ethnic culture. Equivalent-lacking words include, along with culture-bound words, neologisms, i.e. newly coined forms, dialect words, slang, taboo-words, foreign (third language terms, proper names, misspellings, archaisms. Comparison of languages and cultures reveals the various types of culture-bound words. Reasons for using them can be extralinguistic, lexical or stylistic. When translating culture-bound words a translator should be aware of the receptor’s potential problems, take into account his background knowledge and choose the best means of translation.

Bounds for the probability distribution function of the linear ACD process

OpenAIRE

Fernandes, Marcelo

2003-01-01

Rio de Janeiro This paper derives both lower and upper bounds for the probability distribution function of stationary ACD(p, q) processes. For the purpose of illustration, I specialize the results to the main parent distributions in duration analysis. Simulations show that the lower bound is much tighter than the upper bound.

Substrate-Bound Protein Gradients to Study Haptotaxis

Directory of Open Access Journals (Sweden)

Sebastien G. Ricoult

2015-03-01

Full Text Available Cells navigate in response to inhomogeneous distributions of extracellular guidance cues. The cellular and molecular mechanisms underlying migration in response to gradients of chemical cues have been investigated for over a century. Following the introduction of micropipettes and more recently microfluidics for gradient generation, much attention and effort was devoted to study cellular chemotaxis, which is defined as guidance by gradients of chemical cues in solution. Haptotaxis, directional migration in response to gradients of substrate-bound cues, has received comparatively less attention; however it is increasingly clear that in vivo many physiologically relevant guidance proteins – including many secreted cues – are bound to cellular surfaces or incorporated into extracellular matrix and likely function via a haptotactic mechanism. Here, we review the history of haptotaxis. We examine the importance of the reference surface, the surface in contact with the cell that is not covered by the cue, which forms a gradient opposing the gradient of the protein cue and must be considered in experimental designs and interpretation of results. We review and compare microfluidics, contact-printing, light patterning and 3D fabrication to pattern substrate-bound protein gradients in vitro, and focus on their application to study axon guidance. The range of methods to create substrate-bound gradients discussed herein make possible systematic analyses of haptotactic mechanisms. Furthermore, understanding the fundamental mechanisms underlying cell motility will inform bioengineering approaches to program cell navigation and recover lost function.

Kodiak: An Implementation Framework for Branch and Bound Algorithms

Science.gov (United States)

Smith, Andrew P.; Munoz, Cesar A.; Narkawicz, Anthony J.; Markevicius, Mantas

2015-01-01

Recursive branch and bound algorithms are often used to refine and isolate solutions to several classes of global optimization problems. A rigorous computation framework for the solution of systems of equations and inequalities involving nonlinear real arithmetic over hyper-rectangular variable and parameter domains is presented. It is derived from a generic branch and bound algorithm that has been formally verified, and utilizes self-validating enclosure methods, namely interval arithmetic and, for polynomials and rational functions, Bernstein expansion. Since bounds computed by these enclosure methods are sound, this approach may be used reliably in software verification tools. Advantage is taken of the partial derivatives of the constraint functions involved in the system, firstly to reduce the branching factor by the use of bisection heuristics and secondly to permit the computation of bifurcation sets for systems of ordinary differential equations. The associated software development, Kodiak, is presented, along with examples of three different branch and bound problem types it implements.

Asymptotic Sharpness of Bounds on Hypertrees

Directory of Open Access Journals (Sweden)

Lin Yi

2017-08-01

Full Text Available The hypertree can be defined in many different ways. Katona and Szabó introduced a new, natural definition of hypertrees in uniform hypergraphs and investigated bounds on the number of edges of the hypertrees. They showed that a k-uniform hypertree on n vertices has at most (nk−1$\\left( {\\matrix{n \\cr {k - 1} } } \\right$ edges and they conjectured that the upper bound is asymptotically sharp. Recently, Szabó verified that the conjecture holds by recursively constructing an infinite sequence of k-uniform hypertrees and making complicated analyses for it. In this note we give a short proof of the conjecture by directly constructing a sequence of k-uniform k-hypertrees.

Optimal Bounds in Parametric LTL Games

Directory of Open Access Journals (Sweden)

Martin Zimmermann

2011-06-01

Full Text Available We consider graph games of infinite duration with winning conditions in parameterized linear temporal logic, where the temporal operators are equipped with variables for time bounds. In model checking such specifications were introduced as "PLTL" by Alur et al. and (in a different version called "PROMPT-LTL" by Kupferman et al.. We present an algorithm to determine optimal variable valuations that allow a player to win a game. Furthermore, we show how to determine whether a player wins a game with respect to some, infinitely many, or all valuations. All our algorithms run in doubly-exponential time; so, adding bounded temporal operators does not increase the complexity compared to solving plain LTL games.

Effect of Bound Entanglement on the Convertibility of Pure States

International Nuclear Information System (INIS)

Ishizaka, Satoshi

2004-01-01

I show that bound entanglement strongly influences the quantum entanglement processing of pure states: If N distant parties share appropriate bound entangled states with positive partial transpose, all N-partite pure entangled states become inter-convertible by stochastic local operations and classical communication (SLOCC) at the single copy level. This implies that the Schmidt rank of a bipartite pure entangled state can be increased, and that two incomparable tripartite entanglement of the GHZ and W type can be inter-converted by the assistance of bound entanglement. Further, I propose the simplest experimental scheme for the demonstration of the corresponding bound-entanglement-assisted SLOCC. This scheme does not need quantum gates and is feasible for the current experimental technology of linear optics

Determination of total, and bound Se in sera by INAA

International Nuclear Information System (INIS)

Spate, V.L.; Mason, M.M.; Reams, C.L.; Baskett, C.K.; Morris, J.S.; Mills, D.S.

1994-01-01

The comparison between the total selenium in serum ('total Se') with that which is apparently bound to high molecular weight (> 12.000 D) species, presumably proteins ('bound Se') was reported. Nine hundred seventy seven (977) serum samples arising out of a population-based epidemiological study were prepared in duplicate for the determination of 'total Se' by pipeting directly into irradiation vials; and separate duplicate aliquots were dialyzed against DI water for the determination of 'bound Se'. All samples were analyzed by neutron activation analysis via 77m Se (17.4s) A small dialyzable Se component (∼ 6%) ('free Se'), defined as the difference between the 'total Se' minus the 'bound Se', was identified. (author) 2 refs.; 3 figs.; 5 tabs

Violation of a local form of the Lieb-Oxford bound

Science.gov (United States)

Vilhena, J. G.; Räsänen, E.; Lehtovaara, L.; Marques, M. A. L.

2012-05-01

In the framework of density-functional theory, several popular density functionals for exchange and correlation have been constructed to satisfy a local form of the Lieb-Oxford bound. In its original global expression, the bound represents a rigorous lower limit for the indirect Coulomb interaction energy. Here we employ exact-exchange calculations for the G2 test set to show that the local form of the bound is violated in an extensive range of both the dimensionless gradient and the average electron density. Hence, the results demonstrate the severity in the usage of the local form of the bound in functional development. On the other hand, our results suggest alternative ways to construct accurate density functionals for the exchange energy.

Symmetry Parameter Constraints from a Lower Bound on Neutron-matter Energy

Energy Technology Data Exchange (ETDEWEB)

Tews, Ingo [Institute for Nuclear Theory, University of Washington, Seattle, WA 98195-1550 (United States); Lattimer, James M. [Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY 11794-3800 (United States); Ohnishi, Akira [Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502 (Japan); Kolomeitsev, Evgeni E., E-mail: itews@uw.edu, E-mail: james.lattimer@stonybrook.edu, E-mail: ohnishi@yukawa.kyoto-u.ac.jp, E-mail: e.kolomeitsev@gsi.de [Faculty of Natural Sciences, Matej Bel University, Tajovskeho 40, SK-97401 Banska Bystrica (Slovakia)

2017-10-20

We propose the existence of a lower bound on the energy of pure neutron matter (PNM) on the basis of unitary-gas considerations. We discuss its justification from experimental studies of cold atoms as well as from theoretical studies of neutron matter. We demonstrate that this bound results in limits to the density-dependent symmetry energy, which is the difference between the energies of symmetric nuclear matter and PNM. In particular, this bound leads to a lower limit to the volume symmetry energy parameter S {sub 0}. In addition, for assumed values of S {sub 0} above this minimum, this bound implies both upper and lower limits to the symmetry energy slope parameter L , which describes the lowest-order density dependence of the symmetry energy. A lower bound on neutron-matter incompressibility is also obtained. These bounds are found to be consistent with both recent calculations of the energies of PNM and constraints from nuclear experiments. Our results are significant because several equations of state that are currently used in astrophysical simulations of supernovae and neutron star mergers, as well as in nuclear physics simulations of heavy-ion collisions, have symmetry energy parameters that violate these bounds. Furthermore, below the nuclear saturation density, the bound on neutron-matter energies leads to a lower limit to the density-dependent symmetry energy, which leads to upper limits to the nuclear surface symmetry parameter and the neutron-star crust–core boundary. We also obtain a lower limit to the neutron-skin thicknesses of neutron-rich nuclei. Above the nuclear saturation density, the bound on neutron-matter energies also leads to an upper limit to the symmetry energy, with implications for neutron-star cooling via the direct Urca process.

An Upper Bound on the Entropy of Constrained 2d Fields

DEFF Research Database (Denmark)

Forchhammer, Søren; Justesen, Jørn

1998-01-01

An upper bound on the entropy of constrained 2D fields is presented. The constraints have to be symmetric in (at least) one of the two directions. The bound generalizes (in a weaker form) the bound of Calkin and Wilf (see SIAM Journal of Discrete Mathematics, vol.11, p.54-60, 1998) which is valid...

Bilirubin bound to cells does not form photoisomers

International Nuclear Information System (INIS)

Christensen, T.; Kinn, G.

1993-01-01

Cultured cells from one human and one murine cell line were incubated with bilirubin by different methods that allowed bilirubin to be bound to cells. The cells were irradiated with visible light of different wavelengths. Bilirubin bound to human serum albumin was also irradiated with light. After irradiation, bilirubin and its photoisomers were extracted and analyzed by HPLC. No photoisomers were found in samples of irradiated cells, while the types and amounts of photoisomers that were expected from the literature were found in samples of irradiated bilirubin/albumin mixtures. It is concluded that the formation of therapeutically active photoisomers during phototherapy most probably does not take place in skin cells, but most likely in bilirubin bound to albumin in the vessels or in the interstitial space. 16 refs., 2 figs

Cell wall bound anionic peroxidases from asparagus byproducts.

Science.gov (United States)

Jaramillo-Carmona, Sara; López, Sergio; Vazquez-Castilla, Sara; Jimenez-Araujo, Ana; Rodriguez-Arcos, Rocio; Guillen-Bejarano, Rafael

2014-10-08

Asparagus byproducts are a good source of cationic soluble peroxidases (CAP) useful for the bioremediation of phenol-contaminated wastewaters. In this study, cell wall bound peroxidases (POD) from the same byproducts have been purified and characterized. The covalent forms of POD represent >90% of the total cell wall bound POD. Isoelectric focusing showed that whereas the covalent fraction is constituted primarily by anionic isoenzymes, the ionic fraction is a mixture of anionic, neutral, and cationic isoenzymes. Covalently bound peroxidases were purified by means of ion exchange chromatography and affinity chromatography. In vitro detoxification studies showed that although CAP are more effective for the removal of 4-CP and 2,4-DCP, anionic asparagus peroxidase (AAP) is a better option for the removal of hydroxytyrosol (HT), the main phenol present in olive mill wastewaters.

Bounded variation and around

CERN Document Server

Appell, Jürgen; Merentes Díaz, Nelson José

2013-01-01

This monographis a self-contained exposition of the definition and properties of functionsof bounded variation and their various generalizations; the analytical properties of nonlinear composition operators in spaces of such functions; applications to Fourier analysis, nonlinear integral equations, and boundary value problems. The book is written for non-specialists. Every chapter closes with a list of exercises and open problems.

Lying for the Greater Good: Bounded Rationality in a Team

OpenAIRE

Oktay Sürücü

2014-01-01

This paper is concerned with the interaction between fully and boundedly rational agents in situations where their interests are perfectly aligned. The cognitive limitations of the boundedly rational agent do not allow him to fully understand the market conditions and lead him to take non-optimal decisions in some situations. Using categorization to model bounded rationality, we show that the fully rational agent can nudge, i.e., he can manipulate the information he sends and decrease the exp...

On the Catalytic Effect of Water in the Intramolecular Diels–Alder Reaction of Quinone Systems: A Theoretical Study

Directory of Open Access Journals (Sweden)

Renato Contreras

2012-11-01

Full Text Available The mechanism of the intramolecular Diels–Alder (IMDA reaction of benzoquinone 1, in the absence and in the presence of three water molecules, 1w, has been studied by means of density functional theory (DFT methods, using the M05-2X and B3LYP functionals for exploration of the potential energy surface (PES. The energy and geometrical results obtained are complemented with a population analysis using the NBO method, and an analysis based on the global, local and group electrophilicity and nucleophilicity indices. Both implicit and explicit solvation emphasize the increase of the polarity of the reaction and the reduction of activation free energies associated with the transition states (TSs of this IMDA process. These results are reinforced by the analysis of the reactivity indices derived from the conceptual DFT, which show that the increase of the electrophilicity of the quinone framework by the hydrogen-bond formation correctly explains the high polar character of this intramolecular process. Large polarization at the TSs promoted by hydrogen-bonds and implicit solvation by water together with a high electrophilicity-nucleophilicity difference consistently explains the catalytic effects of water molecules.

A self-powered glucose biosensor based on pyrolloquinoline quinone glucose dehydrogenase and bilirubin oxidase operating under physiological conditions.

Science.gov (United States)

Kulkarni, Tanmay; Slaughter, Gymama

2017-07-01

A novel biosensing system capable of simultaneously sensing glucose and powering portable electronic devices such as a digital glucometer is described. The biosensing system consists of enzymatic glucose biofuel cell bioelectrodes functionalized with pyrolloquinoline quinone glucose dehydrogenase (PQQ-GDH) and bilirubin oxidase (BOD) at the bioanode and biocathode, respectively. A dual-stage power amplification circuit is integrated with the single biofuel cell to amplify the electrical power generated. In addition, a capacitor circuit was incorporated to serve as the transducer for sensing glucose. The open circuit voltage of the optimized biofuel cell reached 0.55 V, and the maximum power density achieved was 0.23 mW/ cm 2 at 0.29 V. The biofuel cell exhibited a sensitivity of 0.312 mW/mM.cm 2 with a linear dynamic range of 3 mM - 20 mM glucose. The overall self-powered glucose biosensor is capable of selectively screening against common interfering species, such as ascorbate and urate and exhibited an operational stability of over 53 days, while maintaining 90 % of its activity. These results demonstrate the system's potential to replace the current glucose monitoring devices that rely on external power supply, such as a battery.

Confidence bounds of recurrence-based complexity measures

International Nuclear Information System (INIS)

Schinkel, Stefan; Marwan, N.; Dimigen, O.; Kurths, J.

2009-01-01

In the recent past, recurrence quantification analysis (RQA) has gained an increasing interest in various research areas. The complexity measures the RQA provides have been useful in describing and analysing a broad range of data. It is known to be rather robust to noise and nonstationarities. Yet, one key question in empirical research concerns the confidence bounds of measured data. In the present Letter we suggest a method for estimating the confidence bounds of recurrence-based complexity measures. We study the applicability of the suggested method with model and real-life data.

Quantum Kolmogorov complexity and bounded quantum memory

International Nuclear Information System (INIS)

Miyadera, Takayuki

2011-01-01

The effect of bounded quantum memory in a primitive information protocol has been examined using the quantum Kolmogorov complexity as a measure of information. We employed a toy two-party protocol in which Bob, by using a bounded quantum memory and an unbounded classical memory, estimates a message that was encoded in qubits by Alice in one of the bases X or Z. Our theorem gave a nontrivial effect of the memory boundedness. In addition, a generalization of the uncertainty principle in the presence of quantum memory has been obtained.

Computer simulation of bounded plasmas

International Nuclear Information System (INIS)

Lawson, W.S.

1987-01-01

The problems of simulating a one-dimensional bounded plasma system using particles in a gridded space are systematically explored and solutions to them are given. Such problems include the injection of particles at the boundaries, the solution of Poisson's equation, and the inclusion of an external circuit between the confining boundaries. A recently discovered artificial cooling effect is explained as being a side-effect of quiet injection, and its potential for causing serious but subtle errors in bounded simulation is noted. The methods described in the first part of the thesis are then applied to the simulation of an extension of the Pierce diode problem, specifically a Pierce diode modified by an external circuit between the electrodes. The results of these simulations agree to high accuracy with theory when a theory exists, and also show some interesting chaotic behavior in certain parameter regimes. The chaotic behavior is described in detail

A gauged baby Skyrme model and a novel BPS bound

International Nuclear Information System (INIS)

Adam, C; Naya, C; Sanchez-Guillen, J; Wereszczynski, A

2013-01-01

The baby Skyrme model is a well-known nonlinear field theory supporting topological solitons in two space dimensions. Its action functional consist of a potential term, a kinetic term quadratic in derivatives (the 'nonlinear sigma model term') and the Skyrme term quartic in first derivatives. The limiting case of vanishing sigma model term (the so-called BPS baby Skyrme model) is known to support exact soliton solutions saturating a BPS bound which exists for this model. Further, the BPS model has infinitely many symmetries and conservation laws. Recently it was found that the gauged version of the BPS baby Skyrme model with gauge group U(1) and the usual Maxwell term, too, has a BPS bound and BPS solutions saturating this bound. This BPS bound is determined by a superpotential which has to obey a superpotential equation, in close analogy to the situation in supergravity. Further, the BPS bound and the corresponding BPS solitons only may exist for potentials such that the superpotential equation has a global solution. We also briefly describe some properties of soliton solutions.

Confidence bounds and hypothesis tests for normal distribution coefficients of variation

Science.gov (United States)

Steve P. Verrill; Richard A. Johnson

2007-01-01

For normally distributed populations, we obtain confidence bounds on a ratio of two coefficients of variation, provide a test for the equality of k coefficients of variation, and provide confidence bounds on a coefficient of variation shared by k populations. To develop these confidence bounds and test, we first establish that estimators based on Newton steps from n-...

A duality approach for solving bounded linear programming problems with fuzzy variables based on ranking functions and its application in bounded transportation problems

Science.gov (United States)

Ebrahimnejad, Ali

2015-08-01

There are several methods, in the literature, for solving fuzzy variable linear programming problems (fuzzy linear programming in which the right-hand-side vectors and decision variables are represented by trapezoidal fuzzy numbers). In this paper, the shortcomings of some existing methods are pointed out and to overcome these shortcomings a new method based on the bounded dual simplex method is proposed to determine the fuzzy optimal solution of that kind of fuzzy variable linear programming problems in which some or all variables are restricted to lie within lower and upper bounds. To illustrate the proposed method, an application example is solved and the obtained results are given. The advantages of the proposed method over existing methods are discussed. Also, one application of this algorithm in solving bounded transportation problems with fuzzy supplies and demands is dealt with. The proposed method is easy to understand and to apply for determining the fuzzy optimal solution of bounded fuzzy variable linear programming problems occurring in real-life situations.

Effects of QCD bound states on dark matter relic abundance

Energy Technology Data Exchange (ETDEWEB)

Liew, Seng Pei [Department of Physics, The University of Tokyo,Bunkyo-ku, Tokyo 113-0033 (Japan); Luo, Feng [Kavli IPMU (WPI), UTIAS, The University of Tokyo,Kashiwa, Chiba 277-8583 (Japan)

2017-02-17

We study scenarios where there exists an exotic massive particle charged under QCD in the early Universe. We calculate the formation and dissociation rates of bound states formed by pairs of these particles, and apply the results in dark matter (DM) coannihilation scenarios, including also the Sommerfeld effect. We find that on top of the Sommerfeld enhancement, bound-state effects can further significantly increase the largest possible DM masses which can give the observed DM relic abundance, by ∼30–100% with respect to values obtained by considering the Sommerfeld effect only, for the color triplet or octet exotic particles we consider. In particular, it indicates that the Bino DM mass in the right-handed stop-Bino coannihilation scenario in the Minimal Supersymmetric extension of the Standard Model (MSSM) can reach ∼2.5 TeV, even though the potential between the stop and antistop prior to forming a bound state is repulsive. We also apply the bound-state effects in the calculations of relic abundance of long-lived or metastable massive colored particles, and discuss the implications on the BBN constraints and the abundance of a super-weakly interacting DM. The corrections for the bound-state effect when the exotic massive colored particles also carry electric charges, and the collider bounds are also discussed.

Observations of bound and unbound states of Ce−

International Nuclear Information System (INIS)

Walter, C W; Li, Y-G; Matyas, D J; Alton, R M; Lou, S E; III, R L Field; Gibson, N D; Hanstorp, D

2012-01-01

The negative ion of cerium has been investigated with tunable infrared laser photodetachment spectroscopy over selected photon energy ranges between 0.56 − 0.70 eV. The spectrum reveals several sharp peaks due to negative ion resonances and possible bound-bound transitions in Ce − . The newly observed transitions, together with our previous measurements, provide insight into the rich near-threshold spectrum of this lanthanide negative ion.

Temperature bounds in a model of laminar flames

International Nuclear Information System (INIS)

Kirane, M.; Badraoui, S.

1994-06-01

We consider reaction-diffusion equations coupling temperature and mass fraction in one-step-reaction model of combustion in R N . Uniform temperature bounds are derived when the Lewis number is less than one. This result completes the case of Lewis number greater than one studied by J.D. Avrin and M. Kirane ''Temperature growth and temperature bounds in special cases of combustion models'' (to appear in Applicable Analysis). (author). 5 refs

A Note on the W-S Lower Bound of the MEE Estimation

Directory of Open Access Journals (Sweden)

Badong Chen

2014-02-01

Full Text Available The minimum error entropy (MEE estimation is concerned with the estimation of a certain random variable (unknown variable based on another random variable (observation, so that the entropy of the estimation error is minimized. This estimation method may outperform the well-known minimum mean square error (MMSE estimation especially for non-Gaussian situations. There is an important performance bound on the MEE estimation, namely the W-S lower bound, which is computed as the conditional entropy of the unknown variable given observation. Though it has been known in the literature for a considerable time, up to now there is little study on this performance bound. In this paper, we reexamine the W-S lower bound. Some basic properties of the W-S lower bound are presented, and the characterization of Gaussian distribution using the W-S lower bound is investigated.

Semiclassical bounds in magnetic bottles

Czech Academy of Sciences Publication Activity Database

Barseghyan, Diana; Exner, Pavel; Kovařík, H.; Weidl, T.

2016-01-01

Roč. 28, č. 1 (2016), s. 1650002 ISSN 0129-055X R&D Projects: GA ČR(CZ) GA14-06818S Institutional support: RVO:61389005 Keywords : magnetic Laplacian * discrete spectrum * eigenvalue bounds Subject RIV: BE - Theoretical Physics Impact factor: 1.426, year: 2016

Simple bounds and monotonicity results for finite multi-server exponential tandem queues

NARCIS (Netherlands)

Dijk, van N.M.; Wal, van der J.

1989-01-01

Simple and computationally attractive lower and upper bounds are presented for the call congestion such as those representing multi-server loss or delay stations. Numerical computations indicate a potential usefulness of the bounds for quick engineering purposes. The bounds correspond to

Information theoretic bounds for compressed sensing in SAR imaging

International Nuclear Information System (INIS)

Jingxiong, Zhang; Ke, Yang; Jianzhong, Guo

2014-01-01

Compressed sensing (CS) is a new framework for sampling and reconstructing sparse signals from measurements significantly fewer than those prescribed by Nyquist rate in the Shannon sampling theorem. This new strategy, applied in various application areas including synthetic aperture radar (SAR), relies on two principles: sparsity, which is related to the signals of interest, and incoherence, which refers to the sensing modality. An important question in CS-based SAR system design concerns sampling rate necessary and sufficient for exact or approximate recovery of sparse signals. In the literature, bounds of measurements (or sampling rate) in CS have been proposed from the perspective of information theory. However, these information-theoretic bounds need to be reviewed and, if necessary, validated for CS-based SAR imaging, as there are various assumptions made in the derivations of lower and upper bounds on sub-Nyquist sampling rates, which may not hold true in CS-based SAR imaging. In this paper, information-theoretic bounds of sampling rate will be analyzed. For this, the SAR measurement system is modeled as an information channel, with channel capacity and rate-distortion characteristics evaluated to enable the determination of sampling rates required for recovery of sparse scenes. Experiments based on simulated data will be undertaken to test the theoretic bounds against empirical results about sampling rates required to achieve certain detection error probabilities

Ob the Froissart-Martin bound in spaces with compact dimensions

CERN Document Server

Petrov, V A

2002-01-01

It is shown by the example of the 5-dimensional space-time, that by availability of the additional compact (space-time-like) measurements to the general Minkowski space all the conditions for proving the Froissart-Martin bound retain their force. Thus, by the circumference R -> 0 the theory smoothly transfers to the theory of the neutral scalar field in the 4-dimensional Minkowski space-time. It was assumed in this work, that the masses are bound from below by the non-zero value. The bounds for elastic scattering by absence of the mass gap are trivial, however in this case it is obviously possible to obtain also nontrivial bounds for complete inelastic cross sections. It takes place in the Regge-eikonal approach though there exist no strong proof for it

APS Beyond Positivity Bounds and the Fate of Massive Gravity

CERN Document Server

Bellazzini, Brando; Serra, Javi; Sgarlata, Francesco

2018-04-18

We constrain effective field theories by going beyond the familiar positivity bounds that follow from unitarity, analyticity, and crossing symmetry of the scattering amplitudes. As interesting examples, we discuss the implications of the bounds for the Galileon and ghost-free massive gravity. The combination of our theoretical bounds with the experimental constraints on the graviton mass implies that the latter is either ruled out or unable to describe gravitational phenomena, let alone to consistently implement the Vainshtein mechanism, down to the relevant scales of fifth-force experiments, where general relativity has been successfully tested. We also show that the Galileon theory must contain symmetry-breaking terms that are at most one-loop suppressed compared to the symmetry-preserving ones. We comment as well on other interesting applications of our bounds.

Scaling Limits and Generic Bounds for Exploration Processes

Science.gov (United States)

Bermolen, Paola; Jonckheere, Matthieu; Sanders, Jaron

2017-12-01

We consider exploration algorithms of the random sequential adsorption type both for homogeneous random graphs and random geometric graphs based on spatial Poisson processes. At each step, a vertex of the graph becomes active and its neighboring nodes become blocked. Given an initial number of vertices N growing to infinity, we study statistical properties of the proportion of explored (active or blocked) nodes in time using scaling limits. We obtain exact limits for homogeneous graphs and prove an explicit central limit theorem for the final proportion of active nodes, known as the jamming constant, through a diffusion approximation for the exploration process which can be described as a unidimensional process. We then focus on bounding the trajectories of such exploration processes on random geometric graphs, i.e., random sequential adsorption. As opposed to exploration processes on homogeneous random graphs, these do not allow for such a dimensional reduction. Instead we derive a fundamental relationship between the number of explored nodes and the discovered volume in the spatial process, and we obtain generic bounds for the fluid limit and jamming constant: bounds that are independent of the dimension of space and the detailed shape of the volume associated to the discovered node. Lastly, using coupling techinques, we give trajectorial interpretations of the generic bounds.

Altering pyrroloquinoline quinone nutritional status modulates mitochondrial, lipid, and energy metabolism in rats.

Directory of Open Access Journals (Sweden)

Kathryn Bauerly

Full Text Available We have reported that pyrroloquinoline quinone (PQQ improves reproduction, neonatal development, and mitochondrial function in animals by mechanisms that involve mitochondrial related cell signaling pathways. To extend these observations, the influence of PQQ on energy and lipid relationships and apparent protection against ischemia reperfusion injury are described herein. Sprague-Dawley rats were fed a nutritionally complete diet with PQQ added at either 0 (PQQ- or 2 mg PQQ/Kg diet (PQQ+. Measurements included: 1 serum glucose and insulin, 2 total energy expenditure per metabolic body size (Wt(3/4, 3 respiratory quotients (in the fed and fasted states, 4 changes in plasma lipids, 5 the relative mitochondrial amount in liver and heart, and 6 indices related to cardiac ischemia. For the latter, rats (PQQ- or PQQ+ were subjected to left anterior descending occlusions followed by 2 h of reperfusion to determine PQQ's influence on infarct size and myocardial tissue levels of malondialdehyde, an indicator of lipid peroxidation. Although no striking differences in serum glucose, insulin, and free fatty acid levels were observed, energy expenditure was lower in PQQ- vs. PQQ+ rats and energy expenditure (fed state was correlated with the hepatic mitochondrial content. Elevations in plasma di- and triacylglyceride and β-hydroxybutryic acid concentrations were also observed in PQQ- rats vs. PQQ+ rats. Moreover, PQQ administration (i.p. at 4.5 mg/kg BW for 3 days resulted in a greater than 2-fold decrease in plasma triglycerides during a 6-hour fast than saline administration in a rat model of type 2 diabetes. Cardiac injury resulting from ischemia/reperfusion was more pronounced in PQQ- rats than in PQQ+ rats. Collectively, these data demonstrate that PQQ deficiency impacts a number of parameters related to normal mitochondrial function.

Influence of adding pyrroloquinoline quinone to parenteral nutrition on gut-associated lymphoid tissue.

Science.gov (United States)

Omata, Jiro; Fukatsu, Kazuhiko; Murakoshi, Satoshi; Moriya, Tomoyuki; Ueno, Chikara; Maeshima, Yoshinori; Okamoto, Koichi; Saitoh, Daizoh; Yamamoto, Junji; Hase, Kazuo

2011-09-01

Experimental intravenous (IV) parenteral nutrition (PN) diminishes gut-associated lymphoid tissue (GALT) cell number and function. PN solution cannot maintain GALT at the same level as a normal diet, even when delivered intragastrically (IG). Previous studies demonstrated pyrroloquinoline quinone (PQQ)-deficient mice to be less immunologically responsive. Because standard (STD) PN solution lacks PQQ, PQQ supplementation may prevent PN-induced GALT changes. This study was designed to determine the influence of adding PQQ to PN on GALT. In experiment 1, mice (n = 32) were randomized to chow, IV-STD-PN, and IV-PQQ-PN groups. The chow group was fed chow with the same caloric content as PN. The IV-STD-PN group received STD-PN solution, whereas the IV-PQQ-PN group was given PQQ (3 mcg/d)-enriched PN by the IV route. After 5 days of feeding, lymphocytes were isolated from the Peyer's patch (PPs), intraepithelial space (IE), and lamina propria (LP) of the small intestine. GALT lymphocyte number and phenotype (αβTCR+, γδTCR+, CD4+, CD8+, B220+ cells) and intestinal immunoglobulin A (IgA) level were determined. In experiment 2, mice (n = 28) were randomized to IG-STD-PN or IG-PQQ-PN group. After IG nutrition supports, GALT mass and function were determined as in experiment 1. The IV-PQQ-PN group showed increased PP lymphocyte number and PP CD8+ cell number compared with the IV-STD PN group. The IG-PQQ-PN group had significantly greater PP lymphocyte number and PP CD4+ cell numbers than the IG-STD-PN group. Neither IV nor IG PQQ treatment raised IgA level. PQQ added to PN partly restores GALT mass, although its effects on GALT function remain unclear.

Quantum Bound to Chaos and the Semiclassical Limit

Science.gov (United States)

Kurchan, Jorge

2018-06-01

We discuss the quantum bound on chaos in the context of the free propagation of a particle in an arbitrarily curved surface at low temperatures. The semiclassical calculation of the Lyapunov exponent can be performed in much the same way as the corresponding one for the `Loschmidt echo'. The bound appears here as the impossibility to scatter a wave, by effect of the curvature, over characteristic lengths smaller than the deBroglie wavelength.

Analysis of a proposed crucial test of quantum mechanics

International Nuclear Information System (INIS)

Collett, M.J.; Loudon, R.

1987-01-01

An experiment based on an extension of the Einstein-Podolsky-Rosen argument has been proposed by Popper as a crucial test of the Copenhagen interpretation of quantum mechanics. Here the authors show, by a slightly more complete version of Popper's analysis, although still at a relatively primitive level of sophistication, that the proposed experiment does not in fact provide such a test. (author)

Quantum bounds on Bell inequalities

Science.gov (United States)

Pál, Károly F.; Vértesi, Tamás

2009-02-01

We have determined the maximum quantum violation of 241 tight bipartite Bell inequalities with up to five two-outcome measurement settings per party by constructing the appropriate measurement operators in up to six-dimensional complex and eight-dimensional real-component Hilbert spaces using numerical optimization. Out of these inequalities 129 have been introduced here. In 43 cases higher-dimensional component spaces gave larger violation than qubits, and in three occasions the maximum was achieved with six-dimensional spaces. We have also calculated upper bounds on these Bell inequalities using a method proposed recently. For all but 20 inequalities the best solution found matched the upper bound. Surprisingly, the simplest inequality of the set examined, with only three measurement settings per party, was not among them, despite the high dimensionality of the Hilbert space considered. We also computed detection threshold efficiencies for the maximally entangled qubit pair. These could be lowered in several instances if degenerate measurements were also allowed.

OPRA capacity bounds for selection diversity over generalized fading channels

KAUST Repository

Hanif, Muhammad Fainan; Yang, Hongchuan; Alouini, Mohamed-Slim

2014-01-01

, lower and upper bounds on OPRA capacity for selection diversity scheme are presented. These bounds hold for variety of fading channels including log-normal and generalized Gamma distributed models and have very simple analytic expressions for easy

Combinatorial bounds on the α-divergence of univariate mixture models

KAUST Repository

Nielsen, Frank; Sun, Ke

2017-01-01

We derive lower- and upper-bounds of α-divergence between univariate mixture models with components in the exponential family. Three pairs of bounds are presented in order with increasing quality and increasing computational cost. They are verified

Computing Bounds on Resource Levels for Flexible Plans

Science.gov (United States)

Muscvettola, Nicola; Rijsman, David

2009-01-01

A new algorithm efficiently computes the tightest exact bound on the levels of resources induced by a flexible activity plan (see figure). Tightness of bounds is extremely important for computations involved in planning because tight bounds can save potentially exponential amounts of search (through early backtracking and detection of solutions), relative to looser bounds. The bound computed by the new algorithm, denoted the resource-level envelope, constitutes the measure of maximum and minimum consumption of resources at any time for all fixed-time schedules in the flexible plan. At each time, the envelope guarantees that there are two fixed-time instantiations one that produces the minimum level and one that produces the maximum level. Therefore, the resource-level envelope is the tightest possible resource-level bound for a flexible plan because any tighter bound would exclude the contribution of at least one fixed-time schedule. If the resource- level envelope can be computed efficiently, one could substitute looser bounds that are currently used in the inner cores of constraint-posting scheduling algorithms, with the potential for great improvements in performance. What is needed to reduce the cost of computation is an algorithm, the measure of complexity of which is no greater than a low-degree polynomial in N (where N is the number of activities). The new algorithm satisfies this need. In this algorithm, the computation of resource-level envelopes is based on a novel combination of (1) the theory of shortest paths in the temporal-constraint network for the flexible plan and (2) the theory of maximum flows for a flow network derived from the temporal and resource constraints. The measure of asymptotic complexity of the algorithm is O(N O(maxflow(N)), where O(x) denotes an amount of computing time or a number of arithmetic operations proportional to a number of the order of x and O(maxflow(N)) is the measure of complexity (and thus of cost) of a maximumflow

Majorana bound states in a disordered quantum dot chain

International Nuclear Information System (INIS)

Zhang, P; Nori, Franco

2016-01-01

We study Majorana bound states in a disordered chain of semiconductor quantum dots proximity-coupled to an s -wave superconductor. By calculating its topological quantum number, based on the scattering-matrix method and a tight-binding model, we can identify the topological property of such an inhomogeneous one-dimensional system. We study the robustness of Majorana bound states against disorder in both the spin-independent terms (including the chemical potential and the regular spin-conserving hopping) and the spin-dependent term, i.e., the spin-flip hopping due to the Rashba spin–orbit coupling. We find that the Majorana bound states are not completely immune to the spin-independent disorder, especially when the latter is strong. Meanwhile, the Majorana bound states are relatively robust against spin-dependent disorder, as long as the spin-flip hopping is of uniform sign (i.e., the varying spin-flip hopping term does not change its sign along the chain). Nevertheless, when the disorder induces sign-flip in spin-flip hopping, the topological-nontopological phase transition takes place in the low-chemical-potential region. (paper)

The need to study of bounding accident in reprocessing plant

International Nuclear Information System (INIS)

Segawa, Satoshi; Fujita, Kunio

2013-01-01

There is a clear consensus that the severe accident corresponds to the core damage accident for power reactors. On the other hand, for FCFs, there is no clear consensus on what is the accident to assess the safety in the region of beyond design basis, or what is the accident which has very low probability but large consequence. The need to examine a bounding consequence of each type of accident is explained to advance the rationality of safety management and regulation and, as a result, to reinforce the safety of a reprocessing plant. The likelihood of occurrence of an accident causing a bounding consequence should correspond to that of a severe accident at a nuclear power plant. The bounding consequence will be derived using the deterministic method and sound engineering judgment supplemented by the probabilistic method. Once an agreement on such a concept is reached among regulators, operators and related experts it will help to provide a solid basis to ensure the safety of a reprocessing plant independent of that of a nuclear power plant. In this paper, we show a preliminary risk profile of RRP calculated by QSA (Quantitative Safety Assessment) which JNFL developed. The profile shows that bounding consequences of various accidents in a range of occurrence frequency corresponding to a severe accident at a nuclear power plant. And we find that the bounding consequence of high-level liquid waste boiling is the largest among all in this range. Therefore, the risk of this event is shown in this paper as an example. To build a common consensus about bounding accidents among concerned parties will encourage regulatory body to introduce such an idea for more effective regulation with scientific rationality. Additionally the study of bounding accidents can contribute to substantial development for accident management strategy as reprocessing operators. (authors)

First observation of bound-state β-decay

International Nuclear Information System (INIS)

Jung, M.; Bosch, F.; Beckert, K.; Eickhoff, H.; Folger, H.; Franzke, B.; Kienle, P.; Klepper, O.; Koenig, W.; Kozhuharov, C.; Mann, R.; Moshammer, R.; Nolden, F.; Schaaf, U.; Soff, G.; Spaedtke, P.; Steck, M.; Stoehlker, T.; Suemmerer, K.

1992-06-01

Bound-state Β - decay was observed for the first time by storing bare 66 163 Dy 66+ ions in a heavy-ion storage ring. From the number of 67 163 Ho 66+ daughter ions, measured as a function of the storage time, a half-life of 47 4 +5 - d was derived. By comparing this result with reported half-lives for electron capture (EC) from the M 1 and M 2 shells of neutral 67 163 Ho, bounds for both the Q EC value of neutral 67 163 Ho and for the electron neutrino mass were set. (orig.)

The covariant entropy bound in gravitational collapse

International Nuclear Information System (INIS)

Gao, Sijie; Lemos, Jose P. S.

2004-01-01

We study the covariant entropy bound in the context of gravitational collapse. First, we discuss critically the heuristic arguments advanced by Bousso. Then we solve the problem through an exact model: a Tolman-Bondi dust shell collapsing into a Schwarzschild black hole. After the collapse, a new black hole with a larger mass is formed. The horizon, L, of the old black hole then terminates at the singularity. We show that the entropy crossing L does not exceed a quarter of the area of the old horizon. Therefore, the covariant entropy bound is satisfied in this process. (author)

A Pilot Study on Gait Kinematics of Old Women with Bound Feet

Directory of Open Access Journals (Sweden)

Yan Zhang

2015-01-01

Full Text Available Foot binding has a long and influential history in China. Little is known about biomechanical changes in gait caused by bound foot. The purpose of this study was to investigate the differences in lower limb kinematics between old women with bound feet and normal feet during walking. Six old women subjects (three with bound feet and three controls with normal feet volunteered to participate in this study. Video data were recorded with a high speed video camera and analysed in the SIMI motion analysis software. Compared to normal controls, bound feet subjects had faster gait cadence with shorter stride length as well as smaller ankle and knee range of motion (ROM. During preswing phase, ankle remained to be dorsiflexion for bound foot subjects. The data from bound foot group also demonstrated that toe vertical displacement increased continuously during whole swing phase without a minimum toe clearance (MTC. The findings indicate that older women with bound feet exhibit significant differences in gait pattern compared to those with normal feet, which is characterised by disappeared propulsion/push-off and reduced mobility of lower limb segments.

Analysis of a convenient information bound for general quantum channels

International Nuclear Information System (INIS)

O'Loan, C J

2007-01-01

Open questions from Sarovar and Milburn (2006 J. Phys. A: Math. Gen. 39 8487) are answered. Sarovar and Milburn derived a convenient upper bound for the Fisher information of a one-parameter quantum channel. They showed that for quasi-classical models their bound is achievable and they gave a necessary and sufficient condition for positive operator-valued measures (POVMs) attaining this bound. They asked (i) whether their bound is attainable more generally (ii) whether explicit expressions for optimal POVMs can be derived from the attainability condition. We show that the symmetric logarithmic derivative (SLD) quantum information is less than or equal to the SM bound, i.e., H(θ) ≤ C Y (θ) and we find conditions for equality. As the Fisher information is less than or equal to the SLD quantum information, i.e., F M (θ) ≤ H(θ), we can deduce when equality holds in F M (θ) ≤ C Y (θ). Equality does not hold for all channels. As a consequence, the attainability condition cannot be used to test for optimal POVMs for all channels. These results are extended to multi-parameter channels

Tight bounds on computing error-correcting codes by bounded-depth circuits with arbitrary gates

Czech Academy of Sciences Publication Activity Database

Gál, A.; Hansen, A. K.; Koucký, Michal; Pudlák, Pavel; Viola, E.

2013-01-01

Roč. 59, č. 10 (2013), s. 6611-6627 ISSN 0018-9448 R&D Projects: GA AV ČR IAA100190902 Institutional support: RVO:67985840 Keywords : bounded-depth circuits * error -correcting codes * hashing Subject RIV: BA - General Mathematics Impact factor: 2.650, year: 2013 http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6578188

Tight bounds on computing error-correcting codes by bounded-depth circuits with arbitrary gates

Czech Academy of Sciences Publication Activity Database

Gál, A.; Hansen, A. K.; Koucký, Michal; Pudlák, Pavel; Viola, E.

2013-01-01

Roč. 59, č. 10 (2013), s. 6611-6627 ISSN 0018-9448 R&D Projects: GA AV ČR IAA100190902 Institutional support: RVO:67985840 Keywords : bounded-depth circuits * error-correcting codes * hashing Subject RIV: BA - General Mathematics Impact factor: 2.650, year: 2013 http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6578188

Binding of dicamba to soluble and bound extracellular polymeric substances (EPS) from aerobic activated sludge: a fluorescence quenching study.

Science.gov (United States)

Pan, Xiangliang; Liu, Jing; Zhang, Daoyong; Chen, Xi; Song, Wenjuan; Wu, Fengchang

2010-05-15

Binding of dicamba to soluble EPS (SEPS) and bound EPS (BEPS) from aerobic activated sludge was investigated using fluorescence spectroscopy. Two protein-like fluorescence peaks (peak A with Ex/Em=225 nm/342-344 nm and peak B with Ex/Em=275/340-344 nm) were identified in SEPS and BEPS. Humic-like fluorescence peak C (Ex/Em=270-275 nm/450-460 nm) was only found in BEPS. Fluorescence of the peaks A and B for SEPS and peak A for BEPS were markedly quenched by dicamba at all temperatures whereas fluorescence of peaks B and C for BEPS was quenched only at 298 K. A dynamic process dominated the fluorescence quenching of peak A of both SEPS and BEPS. Fluorescence quenching of peak B and C was governed a static process. The effective quenching constants (logK(a)) were 4.725-5.293 for protein-like fluorophores of SEPS and 4.23-5.190 for protein-like fluorophores of BEPS, respectively. LogK(a) for humic-like substances was 3.85. Generally, SEPS had greater binding capacity for dicamba than BEPS, and protein-like substances bound dicamba more strongly than humic-like substances. Binding of dicamba to SEPS and BEPS was spontaneous and exothermic. Electrostatic force and hydrophobic interaction forces play a crucial role in binding of dicamba to EPS. Copyright © 2010 Elsevier Inc. All rights reserved.

Thermodynamic Upper Bound on Broadband Light Coupling with Photonic Structures

KAUST Repository

Yu, Zongfu

2012-10-01

The coupling between free space radiation and optical media critically influences the performance of optical devices. We show that, for any given photonic structure, the sum of the external coupling rates for all its optical modes are subject to an upper bound dictated by the second law of thermodynamics. Such bound limits how efficient light can be coupled to any photonic structure. As one example of application, we use this upper bound to derive the limit of light absorption in broadband solar absorbers. © 2012 American Physical Society.

A novel, bounding gait in swimming turtles: implications for aquatic locomotor diversity.

Science.gov (United States)

Mayerl, Christopher J; Blob, Richard W

2017-10-15

Turtles are an iconic lineage in studies of animal locomotion, typifying the use of slow, alternating footfalls during walking. Alternating movements of contralateral limbs are also typical during swimming gaits for most freshwater turtles. Here, we report a novel gait in turtles, in which the pleurodire Emydura subglobosa swims using a bounding gait that coordinates bilateral protraction of both forelimbs with bilateral retraction of both hindlimbs. Use of this bounding gait is correlated with increased limb excursion and decreased stride frequency, but not increased velocity when compared with standard swimming strokes. Bounding by E. subglobosa provides a second example of a non-mammalian lineage that can use bounding gaits, and may give insight into the evolution of aquatic flapping. Parallels in limb muscle fascicle properties between bounding turtles and crocodylids suggest a possible musculoskeletal mechanism underlying the use of bounding gaits in particular lineages. © 2017. Published by The Company of Biologists Ltd.

A Partitioning and Bounded Variable Algorithm for Linear Programming

Science.gov (United States)

Sheskin, Theodore J.

2006-01-01

An interesting new partitioning and bounded variable algorithm (PBVA) is proposed for solving linear programming problems. The PBVA is a variant of the simplex algorithm which uses a modified form of the simplex method followed by the dual simplex method for bounded variables. In contrast to the two-phase method and the big M method, the PBVA does…

Supergravity and upper bound on scale of supersymmetry breaking

International Nuclear Information System (INIS)

Kim, J.E.; Nishino, H.

1983-09-01

In locally supersymmetric grand unified models we show rather a model independent upper bound 3x10 11 GeV for the scale of supersymmetry breaking, which is derived by considering SU(2)xU(1) breaking at electro-weak mass scale. This bound necessarily implies the existence of new particles (superpartners) below 10 4 GeV. (author)

Exchange interaction in scattering on the bound state

International Nuclear Information System (INIS)

Arkhipov, A.A.; Savrin, V.I.

1975-01-01

In the framework of the one-time formulation of three-body problem in quantum field theory, the problem of scattering on the bound state is considered for the case when one of the incident particles is identical to one of the particles of the target. It is shown that due to the identical nature of these particles the exchange interaction takes place which can be connected with the mechanism of scattering on the bound state with the rearrangement