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Sample records for singly charged adenine

  1. Molecular simulation of flavin adenine dinucleotide immobilized on charged single-walled carbon nanotubes for biosensor applications.

    Science.gov (United States)

    Yang, Guang; Kang, Zhengzhong; Ye, Xuesong; Wu, Tao; Zhu, Qin

    2012-12-01

    The reconstitution of apo-glucose oxidase (apo-GOx) on single-walled carbon nanotubes (SWNTs) functionalized with the cofactor, flavin adenine dinucleotide (FAD), greatly improved electron transfer turnover rate of the redox reactions in glucose sensing with glucose sensors. The research reported here is aimed to better understand molecular details of affection of the charging SWNT to the conformational changes of FAD, in order to find a rational design and selection scheme of SWNT which is suitable for the FAD and apo-GOx to perform their reconstitution. In this report, molecular simulations of FAD functionalized differently charged SWNTs were carried outin an aqueous environment, with counterions to maintain total charge neutrality. The conformation and orientation changes were observed by both trajectory and quantitative analyses. The simulation results showed that in both uncharged and positively charged SWNT situations, FAD adsorbed onto SWNT at the end of the simulations, which increased the steric resistance of molecules and hindered the reconstitution of apo-GOx and FAD to some degree. By contrast, FAD functionalized negatively charged SWNT maintained its original conformation largely. In addition, negatively charged SWNT may be the best choice for electron transfer mediator for the reconstitution of apo-GOx on relay-cofactor units associated with electrodes. Copyright © 2012 Elsevier Ltd. All rights reserved.

  2. Long-Range Charge Transport in Adenine-Stacked RNA:DNA Hybrids.

    Science.gov (United States)

    Li, Yuanhui; Artés, Juan M; Hihath, Joshua

    2016-01-27

    An extremely important biological component, RNA:DNA can also be used to design nanoscale structures such as molecular wires. The conductance of single adenine-stacked RNA:DNA hybrids is rapidly and reproducibly measured using the break junction approach. The conductance decreases slightly over a large range of molecular lengths, suggesting that RNA:DNA can be used as an oligonucleotide wire. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Crystal structure of a complex between lumiflavin and 2,6-diamino-9-ethylpurine: a flavin adenine dinucleotide model exhibiting charge-transfer interactions.

    Science.gov (United States)

    Scarbrough, F E; Shieh, H; Voet, D

    1976-11-01

    The x-ray structure of the deep red crystalline complex lumiflavin-2,6-diamino-9-ethylpurine has been determined. The flavin and adenine derivatives form hydrogen-bonded base pairs of the Watson-Crick type. The molecules in the crystal also associate via extensively overlapped flavin/adenine and flavin/flavin stacking interactions in which there are several contacts that are closer than van der Waals distances. This, together with the red color of the crystals, is indicative of the formation of a charge-transfer complex.

  4. Absorption by DNA single strands of adenine isolated in vacuo: The role of multiple chromophores

    DEFF Research Database (Denmark)

    Nielsen, L.M.; Pedersen, S.O.; Kirketerp, M.-B.S.

    2012-01-01

    to that for the adenine molecule and the dAMP mononucleotide. Desolvation has little effect on the bandwidth, which implies that inhomogenous broadening of the absorption bands in aqueous solution is of minor importance compared to, e.g., conformational disorder. Finally, at high photon energies, internal conversion...

  5. Charges of Nicotinamide Adenine nucleotides and Adenylate Energy Charge as regulatory parameters of the metabolism in Eschericia coli

    DEFF Research Database (Denmark)

    Andersen, Klaus Bahl; von Meyenburg, Kaspar

    1977-01-01

    NADH/(NADH+NAD), NADPH/(NADPH+NADP) and (ATP+½ADP)/(ATP+ADP+AMP) respectively has the values 0.05, 0.45 and 0.9 during steady state growth. The changes of the charges during changes of growth are examined.......NADH/(NADH+NAD), NADPH/(NADPH+NADP) and (ATP+½ADP)/(ATP+ADP+AMP) respectively has the values 0.05, 0.45 and 0.9 during steady state growth. The changes of the charges during changes of growth are examined....

  6. Nuclear structure and the single charge exchange

    International Nuclear Information System (INIS)

    Oset, E.; Strottman, D.

    1979-01-01

    The influence of nuclear structure on meson-induced single-charge-exchange reactions on light nuclei is discussed within the context of the Glauber approximation. Selection rules which are expected to be approximately obeyed in elastic and inelastic pion and kaon scattering are proposed. Theoretical predictions are presented for (π + ,π 0 ) and (K + ,K 0 ) reactions on 13 C. 14 figures

  7. Charge transport in single crystal organic semiconductors

    Science.gov (United States)

    Xie, Wei

    Organic electronics have engendered substantial interest in printable, flexible and large-area applications thanks to their low fabrication cost per unit area, chemical versatility and solution processability. Nevertheless, fundamental understanding of device physics and charge transport in organic semiconductors lag somewhat behind, partially due to ubiquitous defects and impurities in technologically useful organic thin films, formed either by vacuum deposition or solution process. In this context, single-crystalline organic semiconductors, or organic single crystals, have therefore provided the ideal system for transport studies. Organic single crystals are characterized by their high chemical purity and outstanding structural perfection, leading to significantly improved electrical properties compared with their thin-film counterparts. Importantly, the surfaces of the crystals are molecularly flat, an ideal condition for building field-effect transistors (FETs). Progress in organic single crystal FETs (SC-FETs) is tremendous during the past decade. Large mobilities ~ 1 - 10 cm2V-1s-1 have been achieved in several crystals, allowing a wide range of electrical, optical, mechanical, structural, and theoretical studies. Several challenges still remain, however, which are the motivation of this thesis. The first challenge is to delineate the crystal structure/electrical property relationship for development of high-performance organic semiconductors. This thesis demonstrates a full spectrum of studies spanning from chemical synthesis, single crystal structure determination, quantum-chemical calculation, SC-OFET fabrication, electrical measurement, photoelectron spectroscopy characterization and extensive device optimization in a series of new rubrene derivatives, motivated by the fact that rubrene is a benchmark semiconductor with record hole mobility ~ 20 cm2V-1s-1. With successful preservation of beneficial pi-stacking structures, these rubrene derivatives form

  8. Heat dissipation in relativistic single charged fluids

    Science.gov (United States)

    Garcia-Perciante, A. L.; Sandoval-Villalbazo, A.; Brun-Battistini, D.

    2015-11-01

    When the temperature of a fluid is increased its out of equilibrium behavior is significantly modified. In particular kinetic theory predicts that the heat flux is not solely driven by a temperature gradient but can also be coupled to other thermodynamic vector forces. We explore the nature of heat conduction in a single component charged fluid in special relativity, where the electromagnetic field is introduced as an external force. We obtain an electrothermal effect, similar to the mixture's cross-effect, which is not present in the non-relativistic simple fluid. The general lines of the corresponding calculation will be shown, emphasizing the importance of reference frame invariance and the origin of the extra heat sources, in particular the role of the modified inertia and the difference in fluid's and molecules' proper times. The constitutive equation for the heat flux obtained using Chapman-Enskog's expansion in Marle's approximation will be analyzed together with the corresponding transport coefficients.The impact of this effect in the overall dynamics of the system here considered will be briefly discussed. The authors acknowledge support from CONACyT through grant CB2011/167563.

  9. Charge exchange between singly ionized helium ions

    International Nuclear Information System (INIS)

    Choi, B.H.; Poe, R.T.; Tang, K.T.

    1978-01-01

    The plane-wave Born approximation was used to evaluate the charge transfer cross sections for the reaction He + + He + → He ++ + He. The charge transfer cross section is graphed as a function of incident energy and compared with experimental measurements

  10. Single Gold Nanorod Charge Modulation in an Ion Gel Device.

    Science.gov (United States)

    Collins, Sean S E; Wei, Xingzhan; McKenzie, Thomas G; Funston, Alison M; Mulvaney, Paul

    2016-11-09

    A reliable and reproducible method to rapidly charge single gold nanocrystals in a solid-state device is reported. Gold nanorods (Au NRs) were integrated into an ion gel capacitor, enabling them to be charged in a transparent and highly capacitive device, ideal for optical transmission. Changes in the electron concentration of a single Au NR were observed with dark-field imaging spectroscopy via localized surface plasmon resonance (LSPR) shifts in the scattering spectrum. A time-resolved, laser-illuminated, dark-field system was developed to enable direct measurement of single particle charging rates with time resolution below one millisecond. The added sensitivity of this new approach has enabled the optical detection of fewer than 110 electrons on a single Au NR. Single wavelength resonance shifts provide a much faster, more sensitive method for all surface plasmon-based sensing applications.

  11. Single- and double-charge exchange at low pion energies

    International Nuclear Information System (INIS)

    Baer, H.W.

    1991-01-01

    A review is given of pion single- and double-charge exchange reactions at incident energies of 25 to 65 MeV leading to isobaric analog states, and in the case of double-charge exchange leading to the ground state of the residual nucleus. The crucial role of the higher nuclear transparency at low pion energies for the analysis of the data in terms of single and double scattering is demonstrated. The large effects on double-charge exchange produced by the spatial correlations in nuclear wave functions are evident. The data on 1f 7/2 nuclei at 35 MeV are used to establish the general validity of a shell-model-based two-amplitude model for these transitions. Recent measurements of the energy dependence between 25 and 65 MeV of double-charge exchange cross sections at forward angles are presented and discussed. 33 refs., 19 figs

  12. Genome-wide mapping of methylated adenine residues in pathogenic Escherichia coli using single-molecule real-time sequencing.

    Science.gov (United States)

    Fang, Gang; Munera, Diana; Friedman, David I; Mandlik, Anjali; Chao, Michael C; Banerjee, Onureena; Feng, Zhixing; Losic, Bojan; Mahajan, Milind C; Jabado, Omar J; Deikus, Gintaras; Clark, Tyson A; Luong, Khai; Murray, Iain A; Davis, Brigid M; Keren-Paz, Alona; Chess, Andrew; Roberts, Richard J; Korlach, Jonas; Turner, Steve W; Kumar, Vipin; Waldor, Matthew K; Schadt, Eric E

    2012-12-01

    Single-molecule real-time (SMRT) DNA sequencing allows the systematic detection of chemical modifications such as methylation but has not previously been applied on a genome-wide scale. We used this approach to detect 49,311 putative 6-methyladenine (m6A) residues and 1,407 putative 5-methylcytosine (m5C) residues in the genome of a pathogenic Escherichia coli strain. We obtained strand-specific information for methylation sites and a quantitative assessment of the frequency of methylation at each modified position. We deduced the sequence motifs recognized by the methyltransferase enzymes present in this strain without prior knowledge of their specificity. Furthermore, we found that deletion of a phage-encoded methyltransferase-endonuclease (restriction-modification; RM) system induced global transcriptional changes and led to gene amplification, suggesting that the role of RM systems extends beyond protecting host genomes from foreign DNA.

  13. Charge transient spectroscopy of C 60 single crystals

    Science.gov (United States)

    Baranc̆ok, D.; Halus̆ka, M.; Kuzmany, H.; Nádaz̆dy, V.

    1994-01-01

    Suitability of the charge transient spectroscopy — QTS for the investigation of fullerites is demonstrated. QTS can yield an information on the electrical properties of both the bulk and the interface of fullerites interfaced with metals (insulators, semiconductors) as well as on its bulk phase transition. Our measurements were carried out on C60 single crystals. We observed a single QTS peak which reflects most probably a thermally activated relaxation process (polarization or trap - limited charge emission) in the crystal. The expected phase transition was detected as a step of QTS signal at 255 K. The influence of a thermal treatment in air on the QTS peak was also observed.

  14. Single-charge tunneling in ambipolar silicon quantum dots

    NARCIS (Netherlands)

    Müller, Filipp

    2015-01-01

    Spin qubits in coupled quantum dots (QDs) are promising for future quantum information processing (QIP). A quantum bit (qubit) is the quantum mechanical analogon of a classical bit. In general, each quantum mechanical two-level system can represent a qubit. For the spin of a single charge carrier

  15. Single-sheet identification method of heavy charged particles using ...

    Indian Academy of Sciences (India)

    of the single-sheet particle identification technique in CR-39 and CN-85 polycarbonate by plotting track cone length ... in neutron dosimetry, gamma and cosmic rays detection, heavy ion and nuclear physics and corpuscular ..... [13] R P Henke and E V Benton, Charged particle tracks in polymers: No. 5-A com- puter code for ...

  16. Surface charge modulated aptasensor in a single glass conical nanopore.

    Science.gov (United States)

    Cai, Sheng-Lin; Cao, Shuo-Hui; Zheng, Yu-Bin; Zhao, Shuang; Yang, Jin-Lei; Li, Yao-Qun

    2015-09-15

    In this work, we have proposed a label-free nanopore-based biosensing strategy for protein detection by performing the DNA-protein interaction inside a single glass conical nanopore. A lysozyme binding aptamer (LBA) was used to functionalize the walls of glass nanopore via siloxane chemistry and negatively charged recognition sites were thus generated. The covalent modification procedures and their recognition towards lysozyme of the single conical nanopore were characterized via ionic current passing through the nanopore membrane, which was measured by recording the current-voltage (I-V) curves in 1mM KCl electrolyte at pH=7.4. With the occurring of recognition event, the negatively charged wall was partially neutralized by the positively charged lysozyme molecules, leading to a sensitive change of the surface charge-dependent current-voltage (I-V) characteristics. Our results not only demonstrate excellent selectivity and sensitivity towards the target protein, but also suggest a route to extend this nanopore-based sensing strategy to the biosensing platform designs of a wide range of proteins based on a charge modulation. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. Spin and charge transport study in single crystal organic semiconductors

    Science.gov (United States)

    Raman, Karthik V.; Mulder, Carlijn L.; Baldo, Marc A.; Moodera, Jagadeesh S.

    2009-03-01

    Spin transport studies in amorphous rubrene films have shown exciting and promising results [1]. A large spin diffusion length in these amorphous films has increased the motivation to perform spin transport study in high purity single crystal rubrene. This will provide the fundamental understanding on the spin transport behavior in OS; not influenced by defects or traps. We will present work on small channel single crystal rubrene FET device with magnetic electrodes. For example, our preliminary studies have show mobility for FET with Co electrode to be 0.014cm^2/V-s. A study on the spin and charge transport properties in single crystals of OS with magnetic electrodes is being done and the results will be reported. The influence of gate voltage and applied magnetic field on the transport properties will be discussed. [1] J.H. Shim et al., PRL 100, 226603 (2008)

  18. A compact source for bunches of singly charged atomic ions

    Science.gov (United States)

    Murböck, T.; Schmidt, S.; Andelkovic, Z.; Birkl, G.; Nörtershäuser, W.; Vogel, M.

    2016-04-01

    We have built, operated, and characterized a compact ion source for low-energy bunches of singly charged atomic ions in a vacuum beam line. It is based on atomic evaporation from an electrically heated oven and ionization by electron impact from a heated filament inside a grid-based ionization volume. An adjacent electrode arrangement is used for ion extraction and focusing by applying positive high-voltage pulses to the grid. The method is particularly suited for experimental environments which require low electromagnetic noise. It has proven simple yet reliable and has been used to produce μs-bunches of up to 106 Mg+ ions at a repetition rate of 1 Hz. We present the concept, setup and characterizing measurements. The instrument has been operated in the framework of the SpecTrap experiment at the HITRAP facility at GSI/FAIR to provide Mg+ ions for sympathetic cooling of highly charged ions by laser-cooled 24Mg+.

  19. Inclusive photoproduction of single charged particles at high p T

    Science.gov (United States)

    Apsimon, R. J.; Atkinson, M.; Baake, M.; Bagdasarian, L. S.; Barberis, D.; Brodbeck, T. J.; Brook, N.; Charity, T.; Clegg, A. B.; Coyle, P.; Danaher, S.; Danagulian, S.; Davenport, M.; Dickinson, B.; Diekmann, B.; Donnachie, A.; Doyle, A. T.; Eades, J.; Ellison, R. J.; Flower, P. S.; Foster, J. M.; Galbraith, W.; Galumian, P. I.; Gapp, C.; Gebert, F.; Hallewell, G.; Heinloth, K.; Henderson, R. C. W.; Hickman, M. T.; Hoeger, C.; Holzkamp, S.; Hughes-Jones, R. E.; Ibbotson, M.; Jakob, H. P.; Joseph, D.; Keemer, N. R.; Kingler, J.; Koersgen, G.; Kolya, S. D.; Lafferty, G. D.; McCann, H.; McClatchey, R.; McManus, C.; Mercer, D.; Morris, J. A. G.; Morris, J. V.; Newton, D.; O'Connor, A.; Oedingen, R.; Oganesian, A. G.; Ottewell, P. J.; Paterson, C. N.; Paul, E.; Reid, D.; Rotscheidt, H.; Sharp, P. H.; Soeldner-Rembold, S.; Thacker, N. A.; Thompson, L.; Thompson, R. J.; Voigtlaender-Tetzner, A.; Waterhouse, J.; Weigend, A. S.; Wilson, G. W.

    1989-03-01

    Single charged-particle inclusive cross sections for photon, pion and kaon beams on hydrogen at the CERN-SPS are presented as functions of p T and x F . Data cover the range 0.01.6 GeV/c for the photon-induced data. Using the hadron-induced data to estimate the hadronic behaviour of the photon, the difference distributions and ratios of cross sections are a measure of the contribution of the point-like photon interactions. The data are compared with QCD calculations and show broadly similar features.

  20. Light-Induced Charge Transport within a Single Asymmetric Nanowire

    Energy Technology Data Exchange (ETDEWEB)

    LIU, CHONG; HWANG, YUN YEONG; JEONG, HOON EIU; YANG, PEIDONG

    2011-01-21

    Artificial photosynthetic systems using semiconductor materials have been explored for more than three decades in order to store solar energy in chemical fuels such as hydrogen. By mimicking biological photosynthesis with two light-absorbing centers that relay excited electrons in a nanoscopic space, a dual-band gap photoelectrochemical (PEC) system is expected to have higher theoretical energy conversion efficiency than a single band gap system. This work demonstrates the vectorial charge transport of photo-generated electrons and holes within a single asymmetric Si/TiO2 nanowire using Kelvin probe force microscopy (KPFM). Under UV illumination, higher surface potential was observed on the n-TiO₂ side, relative to the potential of the p-Si side, as a result of majority carriers’ recombination at the Si/TiO₂ interface. These results demonstrate a new approach to investigate charge separation and transport in a PEC system. This asymmetric nanowire heterostructure, with a dual band gap configuration and simultaneously exposed anode and cathode surfaces represents an ideal platform for the development of technologies for the generation of solar fuels, although better photoanode materials remain to be discovered.

  1. Measuring charge density of electron beam single nanosecond pulses

    International Nuclear Information System (INIS)

    Gonchar, A.I.; Nesterenko, V.S.; Fazkullin, V.A.

    1982-01-01

    A description is presented of a probe design and electrometric repeater circuit and technique for measuring the charge (current) density of electron beam single pulses by integrating current at a reference capacitor with a subsequent registering of voltage across the capacitor. The probe consists of a band-type signal electrodes and two oval cross-section sleeves: external and internal with larger and smaller rectangular openings, respectively. The external sleeve has antidynatron grid located over the hole. The design employs integer nickel sleever - the cores of electron tube cathodes. The signal electrode is made of nickel band 0.15 mm thick. The probe elements are insulated from each other along the whole length with a layer of teflon band (30 μm), with rectangular openings cut in compliance with the sleeve openings. The measurement range is from 0.4x10 - 9 to 1x10 - 7 C/cm 2 . The rated accuracy of measurements is no worse than +-5% for the beam energy of 0.2 to 3 KeV. The ultimate parameters the charge density - 6 C/cm 2 and direct current density 3 mA/cm 2 - are specified by the breakdown voltage (200 V) of the input capacitor and probe insulation

  2. Bound anionic states of adenine

    Energy Technology Data Exchange (ETDEWEB)

    Haranczyk, Maciej; Gutowski, Maciej S; Li, Xiang; Bowen, Kit H

    2007-03-20

    Anionic states of nucleic acid bases are involved in DNA damage by low-energy electrons and in charge transfer through DNA. Previous gas phase studies of free, unsolvated nucleic acid base parent anions probed only dipole-bound states, which are not present in condensed phase environments, but did not observe valence anionic states, which for purine bases, are thought to be adiabatically unbound. Contrary to this expectation, we have demonstrated that some thus far ignored tautomers of adenine, which result from enamine-imine transformations, support valence anionic states with electron vertical detachment energies as large as 2.2 eV, and at least one of these anionic tautomers is adiabatically bound. Moreover, we predict that the new anionic tautomers should also dominate in solutions and should be characterized by larger values of electron vertical detachment energy than the canonical valence anion. All of the new-found anionic tautomers might be formed in the course of dissociative electron attachment followed by a hydrogen atom attachment to a carbon atom, and they might affect the structure and properties of DNA and RNA exposed to low-energy electrons. The discovery of these valence anionic states of adenine was facilitated by the development of: (i) a new experimental method for preparing parent anions of nucleic acid bases for photoelectron experiments, and (ii) a new combinatorial/ quantum chemical approach for identification of the most stable tautomers of organic molecules. The computational portion of this work was supported by the: (i) Polish State Committee for Scientific Research (KBN) Grants: DS/8000-4-0140-7 (M.G.) and N204 127 31/2963 (M.H.), (ii) European Social Funds (EFS) ZPORR/2.22/II/2.6/ARP/U/2/05 (M.H.), and (iii) US DOE Office of Biological and Environmental Research, Low Dose Radiation Research Program (M.G.). M.H. holds the Foundation for Polish Science (FNP) award for young scientists. The calculations were performed at the Academic

  3. Intrinsic Charge Carrier Mobility in Single-Layer Black Phosphorus.

    Science.gov (United States)

    Rudenko, A N; Brener, S; Katsnelson, M I

    2016-06-17

    We present a theory for single- and two-phonon charge carrier scattering in anisotropic two-dimensional semiconductors applied to single-layer black phosphorus (BP). We show that in contrast to graphene, where two-phonon processes due to the scattering by flexural phonons dominate at any practically relevant temperatures and are independent of the carrier concentration n, two-phonon scattering in BP is less important and can be considered negligible at n≳10^{13}  cm^{-2}. At smaller n, however, phonons enter in the essentially anharmonic regime. Compared to the hole mobility, which does not exhibit strong anisotropy between the principal directions of BP (μ_{xx}/μ_{yy}∼1.4 at n=10^{13} cm^{-2} and T=300  K), the electron mobility is found to be significantly more anisotropic (μ_{xx}/μ_{yy}∼6.2). Absolute values of μ_{xx} do not exceed 250 (700)  cm^{2} V^{-1} s^{-1} for holes (electrons), which can be considered as an upper limit for the mobility in BP at room temperature.

  4. Nuclear isovector giant resonances excited by pion single charge exchange

    International Nuclear Information System (INIS)

    King, B.H.

    1993-07-01

    This thesis is an experimental study of isovector giant resonances in light nuclei excited by pion single charge exchange reactions. Giant dipole resonances in light nuclei are known to be highly structured. For the mass 9 and 13 giant dipole resonances, isospin considerations were found to be very important to understanding this structure. by comparing the excitation functions from cross section measurements of the (π + , π 0 ) and (π, π 0 ) inclusive reactions, the authors determined the dominant isospin structure of the analog IVGR's. The comparison was made after decomposing the cross section into resonant and non-resonant components. This decomposition is made in the framework of strong absorption and quasi-free scattering. Measurements in the region of the isovector giant dipole resonances (IVGDR) were made to cover the inclusive angular distributions out to the second minimum. Study of the giant resonance decay process provides further understanding of the resonances. This study was carried out by observing the (π + , π 0 p) coincident reactions involving the resonances of 9 B and 13 N excited from 9 Be and 13 C nuclei. These measurements determined the spectra of the decay protons. This method also permitted a decomposition of the giant resonances into their isospin components. The multipolarities of the resonances were revealed by the decay proton angular correlations which, for dipoles, are of the form 1 + A 2 P 2 (cos θ)

  5. A Novel Nicotinamide Adenine Dinucleotide Correction Method for Mitochondrial Ca(2+) Measurement with FURA-2-FF in Single Permeabilized Ventricular Myocytes of Rat.

    Science.gov (United States)

    Lee, Jeong Hoon; Ha, Jeong Mi; Leem, Chae Hun

    2015-07-01

    Fura-2 analogs are ratiometric fluoroprobes that are widely used for the quantitative measurement of [Ca(2+)]. However, the dye usage is intrinsically limited, as the dyes require ultraviolet (UV) excitation, which can also generate great interference, mainly from nicotinamide adenine dinucleotide (NADH) autofluorescence. Specifically, this limitation causes serious problems for the quantitative measurement of mitochondrial [Ca(2+)], as no available ratiometric dyes are excited in the visible range. Thus, NADH interference cannot be avoided during quantitative measurement of [Ca(2+)] because the majority of NADH is located in the mitochondria. The emission intensity ratio of two different excitation wavelengths must be constant when the fluorescent dye concentration is the same. In accordance with this principle, we developed a novel online method that corrected NADH and Fura-2-FF interference. We simultaneously measured multiple parameters, including NADH, [Ca(2+)], and pH/mitochondrial membrane potential; Fura-2-FF for mitochondrial [Ca(2+)] and TMRE for Ψm or carboxy-SNARF-1 for pH were used. With this novel method, we found that the resting mitochondrial [Ca(2+)] concentration was 1.03 µM. This 1 µM cytosolic Ca(2+) could theoretically increase to more than 100 mM in mitochondria. However, the mitochondrial [Ca(2+)] increase was limited to ~30 µM in the presence of 1 µM cytosolic Ca(2+). Our method solved the problem of NADH signal contamination during the use of Fura-2 analogs, and therefore the method may be useful when NADH interference is expected.

  6. Single-Bunch Stability With Direct Space Charge

    CERN Multimedia

    Oeftiger, Adrian

    2017-01-01

    Previous studies have shown the suppressing effect of direct space charge on impedance-driven head-tail instabilities. The present work investigates transverse stability for the HL-LHC scenario based on our macro-particle simulation tool PyHEADTAIL using realistic bunch distributions. The impact of selfconsistent modelling is briefly discussed for non-linear space charge forces. We study how space charge pushes the instability threshold for the transverse mode coupling instability (TMCI) occurring between mode 0 and -1. Next we consider finite chromaticity: in absence of space charge, the impedance model predicts head-tail instabilities. For a selected case below TMCI threshold at Q0 = 5, we demonstrate the stabilising effect of space charge. Finally, we compare simulation results to past LHC measurements.

  7. KNO scaling analysis of singly charged projectile fragments at relativistic energies

    International Nuclear Information System (INIS)

    Marimuthu, N.; Singh, V.; Inbanathan, S.S.R.

    2016-01-01

    This research article deals with the KNO scaling behaviour of singly charged projectile fragments emitted during 84 Kr 36 interactions with nuclear emulsion detector at around one GeV per nucleon. We observed that singly charged projectile fragments are strongly obeying the KNO scaling behaviour. (author)

  8. The charge collection in single side silicon microstrip detectors

    CERN Document Server

    Eremin, V V; Roe, S; Ruggiero, G; Weilhammer, Peter

    2003-01-01

    The transient current technique has been used to investigate signal formation in unirradiated silicon microstrip detectors, which are similar in geometry to those developed for the ATLAS experiment at LHC. Nanosecond pulsed infrared and red lasers were used to induce the signals under study. Two peculiarities in the detector performance were observed: an unexpectedly slow rise to the signal induced in a given strip when signals are injected opposite to the strip, and a long duration of the induced signal in comparison with the calculated drift time of charge carriers through the detector thickness - with a significant fraction of the charge being induced after charge carrier arrival. These major effects and details of the detector response for different positions of charge injection are discussed in the context of Ramo's theorem and compared with predictions arising from the more commonly studied phenomenon of signal formation in planar pad detectors.

  9. Deterministic Electrical Charge-State Initialization of Single Nitrogen-Vacancy Center in Diamond

    Directory of Open Access Journals (Sweden)

    Y. Doi

    2014-03-01

    Full Text Available Apart from applications in classical information-processing devices, the electrical control of atomic defects in solids at room temperature will have a tremendous impact on quantum devices that are based on such defects. In this study, we demonstrate the electrical manipulation of individual prominent representatives of such atomic solid-state defects, namely, the negative charge state of single nitrogen-vacancy defect centers (NV^{−} in diamond. We experimentally demonstrate, deterministic, purely electrical charge-state initialization of individual NV centers. The NV centers are placed in the intrinsic region of a p-i-n diode structure that facilitates the delivery of charge carriers to the defect for charge-state switching. The charge-state dynamics of a single NV center were investigated by time-resolved measurements and a nondestructive single-shot readout of the charge state. Fast charge-state switching rates (from negative to neutrally charged defects, which are greater than 0.72 ± 0.10  μs^{−1}, were realized. Furthermore, in no-operation mode, the realized charge states were stable for presumably much more than 0.45 s. We believe that the results obtained are useful not only for ultrafast electrical control of qubits, long T_{2} quantum memory, and quantum sensors associated with single NV centers but also for classical memory devices based on single atomic storage bits working under ambient conditions.

  10. Single charging events on colloidal particles in a nonpolar liquid with surfactant

    Science.gov (United States)

    Schreuer, Caspar; Vandewiele, Stijn; Brans, Toon; Strubbe, Filip; Neyts, Kristiaan; Beunis, Filip

    2018-01-01

    Electrical charging of colloidal particles in nonpolar liquids due to surfactant additives is investigated intensively, motivated by its importance in a variety of applications. Most methods rely on average electrophoretic mobility measurements of many particles, which provide only indirect information on the charging mechanism. In the present work, we present a method that allows us to obtain direct information on the charging mechanism, by measuring the charge fluctuations on individual particles with a precision higher than the elementary charge using optical trapping electrophoresis. We demonstrate the capabilities of the method by studying the influence of added surfactant OLOA 11000 on the charging of single colloidal PMMA particles in dodecane. The particle charge and the frequency of charging events are investigated both below and above the critical micelle concentration (CMC) and with or without applying a DC offset voltage. It is found that at least two separate charging mechanisms are present below the critical micelle concentration. One mechanism is a process where the particle is stripped from negatively charged ionic molecules. An increase in the charging frequency with increased surfactant concentration suggests a second mechanism that involves single surfactant molecules. Above the CMC, neutral inverse micelles can also be involved in the charging process.

  11. Single-sheet identification method of heavy charged particles using ...

    Indian Academy of Sciences (India)

    The theoretical and experimental investigations of the penetration of charged particles in matter played a very important role in the development of modern physics. Solid state nuclear track detectors have become one of the most important tools for many branches of science and technology. An attempt has been made to ...

  12. Electrochemical charging of the single-layer graphene membrane

    Czech Academy of Sciences Publication Activity Database

    Komínková, Zuzana; Kalbáč, Martin

    2016-01-01

    Roč. 253, č. 12 (2016), s. 2331-2335 ISSN 0370-1972 R&D Projects: GA MŠk LL1301; GA ČR(CZ) GBP208/12/G016 Institutional support: RVO:61388955 Keywords : electrochemical charging * graphene membrane * in situ Raman spectroelectrochemistry Subject RIV: CG - Electrochemistry Impact factor: 1.674, year: 2016

  13. Control of single-electron charging of metallic nanoparticles onto amorphous silicon surface.

    Science.gov (United States)

    Weis, Martin; Gmucová, Katarína; Nádazdy, Vojtech; Capek, Ignác; Satka, Alexander; Kopáni, Martin; Cirák, Július; Majková, Eva

    2008-11-01

    Sequential single-electron charging of iron oxide nanoparticles encapsulated in oleic acid/oleyl amine envelope and deposited by the Langmuir-Blodgett technique onto Pt electrode covered with undoped hydrogenated amorphous silicon film is reported. Single-electron charging (so-called quantized double-layer charging) of nanoparticles is detected by cyclic voltammetry as current peaks and the charging effect can be switched on/off by the electric field in the surface region induced by the excess of negative/positive charged defect states in the amorphous silicon layer. The particular charge states in amorphous silicon are created by the simultaneous application of a suitable bias voltage and illumination before the measurement. The influence of charged states on the electric field in the surface region is evaluated by the finite element method. The single-electron charging is analyzed by the standard quantized double layer model as well as two weak-link junctions model. Both approaches are in accordance with experiment and confirm single-electron charging by tunnelling process at room temperature. This experiment illustrates the possibility of the creation of a voltage-controlled capacitor for nanotechnology.

  14. Charge collection measurements in single-type column 3D sensors

    International Nuclear Information System (INIS)

    Scaringella, M.; Polyakov, A.; Sadrozinski, H.F.-W.; Bruzzi, M.; Tosi, C.; Boscardin, M.; Piemonte, C.; Pozza, A.; Ronchin, S.; Zorzi, N.; Dalla Betta, G.-F.

    2007-01-01

    We report on charge collection studies on 3D silicon detectors of single-type column n-diffusions in p-substrate, configured either as strip or as pad detectors. The charge is generated by penetrating beta particles from a 90 Sr source which, together with a scintillation counter, serves as an electron telescope. The charge collection as a function of bias voltage is compared with the depletion thickness derived from the measured C-V characteristics

  15. Charge collection measurements with p-type Magnetic Czochralski silicon single pad detectors

    International Nuclear Information System (INIS)

    Tosi, C.; Bruzzi, M.; Macchiolo, A.; Scaringella, M.; Petterson, M.K.; Sadrozinski, H.F.-W.; Betancourt, C.; Manna, N.; Creanza, D.; Boscardin, M.; Piemonte, C.; Zorzi, N.; Borrello, L.; Messineo, A.

    2007-01-01

    The charge collected from beta source particles in single pad detectors produced on p-type Magnetic Czochralski (MCz) silicon wafers has been measured before and after irradiation with 26 MeV protons. After a 1 MeV neutron equivalent fluence of 1x10 15 cm -2 the collected charge is reduced to 77% at bias voltages below 900 V. This result is compared with previous results from charge collection measurements

  16. Single molecule charge transport : From a quantum mechanical to a classical description

    NARCIS (Netherlands)

    Kocherzhenko, A.A.; Grozema, F.C.; Siebbeles, L.D.A.

    2010-01-01

    This paper explores charge transport at the single molecule level. The conductive properties of both small organic molecules and conjugated polymers (molecular wires) are considered. In particular, the reasons for the transition from fully coherent to incoherent charge transport and the approaches

  17. Glass coated single grid for charged particle acceleration

    Science.gov (United States)

    Banks, B. A.; Nakanishi, S.

    1968-01-01

    Glass coating is used on a single grid accelerator system for ion thrusters. The uniformly thin, smooth, dense, impervious glass coating has a high dielectric strength and is firmly bonded to the accelerator grid.

  18. A graphene quantum dot with a single electron transistor as an integrated charge sensor

    Science.gov (United States)

    Wang, Lin-Jun; Cao, Gang; Tu, Tao; Li, Hai-Ou; Zhou, Cheng; Hao, Xiao-Jie; Su, Zhan; Guo, Guang-Can; Jiang, Hong-Wen; Guo, Guo-Ping

    2010-12-01

    A quantum dot (QD) with an integrated charge sensor is becoming a common architecture for a spin or charge based solid state qubit. To implement such a structure in graphene, we have fabricated a twin-dot structure in which the larger dot serves as a single electron transistor (SET) to read out the charge state of the nearby gate controlled small QD. A high SET sensitivity of 10-3e/√Hz allowed us to probe Coulomb charging as well as excited state spectra of the QD, even in the regime where the current through the QD is too small to be measured by conventional transport means.

  19. The single-sink fixed-charge transportation problem: Applications and solution methods

    DEFF Research Database (Denmark)

    Goertz, Simon; Klose, Andreas

    2007-01-01

    The single-sink fixed-charge transportation problem (SSFCTP) consists in finding a minimum cost flow from a number of supplier nodes to a single demand node. Shipping costs comprise costs proportional to the amount shipped as well as a fixed-charge. Although the SSFCTP is an important special case...... of the well-known fixed-charge transportation problem, just a few methods for solving this problem have been proposed in the literature. After summarising some applications of this problem arising in manufacturing and transportation, we give an overview on approximation algorithms and worst-case results....... Finally, we briefly compare some exact solution algorithms for this problem....

  20. Detection of charged particles with a methylammonium lead tribromide perovskite single crystal

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Qiang [Nuclear Engineering Program, Department of Mechanical and Aerospace Engineering, The Ohio State University, Columbus, Ohio 43210 (United States); Wei, Haotong; Wei, Wei [Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska 68588 (United States); Chuirazzi, William; DeSantis, Dylan [Nuclear Engineering Program, Department of Mechanical and Aerospace Engineering, The Ohio State University, Columbus, Ohio 43210 (United States); Huang, Jinsong, E-mail: jhuang2@unl.edu [Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska 68588 (United States); Cao, Lei, E-mail: cao.152@osu.edu [Nuclear Engineering Program, Department of Mechanical and Aerospace Engineering, The Ohio State University, Columbus, Ohio 43210 (United States)

    2017-03-11

    Methylammonium lead tribromide (MAPbBr{sub 3}) perovskite crystals have attracted significant attention due to their attractive performance in various optoelectronic applications such as solar cells, light-emitting devices, photodetectors, and recently in X-ray detectors. In this study, we demonstrate a possible use of perovskite-based devices for detection of charged particles (which can be applied in basic scientific research, health physics, and environmental analysis) and investigate the mechanism of fundamental charge transport inside perovskite crystals. It was found that inexpensive MAPbBr{sub 3} single crystals could be used for measuring the energy spectrum of charged particles through direct collection of the produced charge. After fitting the plot of the centroid peak position versus voltage with the Hecht equation for single-polarity charge transport, the obtained hole mobility-lifetime product was in the range of (0.4–1.6)×10{sup −3} cm{sup 2}/V.

  1. A Study of Charged Current Single Charged Pion Productions on Carbon in a Few-GeV Neutrino Beam

    Energy Technology Data Exchange (ETDEWEB)

    Hiraide, Katsuki [Kyoto Univ. (Japan)

    2009-01-01

    Understanding single charged pion production via neutrino-nucleus charged current interaction in the neutrino energy region of a few GeV is essential for future neutrino oscillation experiments since this process is a dominant background for vμ → vx oscillation measurements. There are two contributions to this process: single pion production via baryonic resonance (vμN → μ-+) and coherent pion production interacting with the entire nucleus (vμA → μ-+), where N is nucleon in the nucleus and A is the nucleus. The purpose of the study presented in this thesis is a precise measurement of charged current single charged pion productions, resonant and coherent pion productions, with a good final state separation in the neutrino energy region of a few GeV. In this thesis, we focus on the study of charged current coherent pion production from muon neutrinos scattering on carbon, vμ 12C → μ-12+, in the SciBooNE experiment. This is motivated by the fact that without measuring this component first, the precise determination of resonant pion production cross section can not be achieved since the contribution of coherent pion production in the region of small muon scattering angle is not small. Furthermore, the coherent process is particularly interesting because it is deeply rooted in fundamental physics via Adler's partially conserved axial-vector current theorem. We took data from June 2007 until August 2008, in both the neutrino and antineutrino beam. In total, 2.52 x 1020 protons on target were collected. We have performed a search for charged current coherent pion production by using SciBooNE's full neutrino data set, corresponding to 0.99 x 1020 protons on target. No evidence for coherent pion production is observed. We set 90% confidence level upper limits on the cross section ratio

  2. Electrochemical Charging of Individual Single-Walled Carbon Nanotubes

    Czech Academy of Sciences Publication Activity Database

    Kalbáč, Martin; Farhat, H.; Kavan, Ladislav; Kong, J.; Sasaki, K.; Saito, R.; Dresselhaus, M. S.

    2009-01-01

    Roč. 3, č. 8 (2009), s. 2320-2328 ISSN 1936-0851 R&D Projects: GA ČR GC203/07/J067; GA AV ČR IAA400400804; GA AV ČR IAA400400911; GA AV ČR KAN200100801; GA MŠk ME09060 Institutional research plan: CEZ:AV0Z40400503 Keywords : single-walled carbon nanotubes * Raman spectroscopy * electrochemical gating * spectroelectrochemistry Subject RIV: CG - Electrochemistry Impact factor: 7.493, year: 2009

  3. Large Silver Halide Single Crystals as Charged Particle Track Detectors

    Science.gov (United States)

    Kusmiss, J. H.

    1972-01-01

    The trajectory of the particle is made visible under a microscope by the accumulation of metallic silver at regions of the lattice damaged by the particle. This decoration of the particle track is accomplished by exposure of the crystal to light. The decoration of normally present lattice imperfections such as dislocations can be suppressed by the addition to the crystal of less than ten parts per million of a suitable polyvalent metal impurity. An account of some preliminary attempts to grow thin single crystals of AgCl is given also, and suggestions for a more refined technique are offered.

  4. Dibenzotetraaza[14]annulene-adenine conjugate recognizes complementary poly dT among ss-DNA/ss-RNA sequences.

    Science.gov (United States)

    Radić Stojković, Marijana; Škugor, Marko; Tomić, Sanja; Grabar, Marina; Smrečki, Vilko; Dudek, Łukasz; Grolik, Jarosław; Eilmes, Julita; Piantanida, Ivo

    2013-06-28

    Among three novel DBTAA derivatives only the DBTAA-propyl-adenine conjugate showed recognition of the consecutive oligo dT sequence by increased affinity and specific induced chirooptical response in comparison to other single stranded RNA and DNA; whereby of particular importance is the up until now unique efficient differentiation between dT and rU. At variance, its close analogue DBTAA-hexyl-adenine did not reveal any selectivity between ss-DNA/RNA pointing out the important role of steric factors (linker length); moreover non-selectivity of the reference compound (, lacking adenine) stressed the importance of adenine interactions in the selectivity.

  5. Unbiased, complete solar charging of a neutral flow battery by a single Si photocathode

    DEFF Research Database (Denmark)

    Wedege, Kristina; Bae, Dowon; Dražević, Emil

    2018-01-01

    Solar redox flow batteries have attracted attention as a possible integrated technology for simultaneous conversion and storage of solar energy. In this work, we review current efforts to design aqueous solar flow batteries in terms of battery electrolyte capacity, solar conversion efficiency...... and depth of solar charge. From a materials cost and design perspective, a simple, cost-efficient, aqueous solar redox flow battery will most likely incorporate only one semiconductor, and we demonstrate here a system where a single photocathode is accurately matched to the redox couples to allow...... for a complete solar charge. The single TiO2 protected Si photocathode with a catalytic Pt layer can fully solar charge a neutral TEMPO-sulfate/ferricyanide battery with a cell voltage of 0.35 V. An unbiased solar conversion efficiency of 1.6% is obtained and this system represents a new strategy in solar RFBs...

  6. Solving the Single-Sink, Fixed-Charge, Multiple-Choice Transportation Problem by Dynamic Programming

    DEFF Research Database (Denmark)

    Rauff Lind Christensen, Tue; Klose, Andreas; Andersen, Kim Allan

    The Single-Sink, Fixed-Charge, Multiple-Choice Transportation Problem (SSFCMCTP) is a problem with versatile applications. This problem is a generalization of the Single-Sink, Fixed-Charge Transportation Problem (SSFCTP), which has a fixed-charge, linear cost structure. However, in at least two...... are neglected in the SSFCTP. The SSFCMCTP overcome this problem by incorporating a staircase cost structure in the cost function instead of the usual one used in SSFCTP. We present a dynamic programming algorithm for the resulting problem. To enhance the performance of the generic algorithm a number...... of enhancements is employed. The problem instance is reduced by variable pegging using a Lagrangean relaxation from which also a flow augmentation scheme is derived. Additionally a reduction in the search space is employed along with a variable transformation which generalizes a transformation known from...

  7. Single-particle thermal diffusion of charged colloids: Double-layer theory in a temperature gradient

    NARCIS (Netherlands)

    Dhont, J.K.G.; Briels, Willem J.

    2008-01-01

    The double-layer contribution to the single-particle thermal diffusion coefficient of charged, spherical colloids with arbitrary double-layer thickness is calculated and compared to experiments. The calculation is based on an extension of the Debye-Hückel theory for the double-layer structure that

  8. Observation of Frenkel and charge transfer excitons in pentacene single crystals using spectroscopic generalized ellipsometry

    NARCIS (Netherlands)

    Qi, Dongchen; Su, Haibin; Bastjan, M.; Jurchescu, O. D.; Palstra, T. M.; Wee, Andrew T. S.; Ruebhausen, M.; Rusydi, A.; Rübhausen, M.

    2013-01-01

    We report on the emerging and admixture of Frenkel and charge transfer (CT) excitons near the absorption onset in pentacene single crystals. Using high energy-resolution spectroscopic generalized ellipsometry with in-plane polarization dependence, the excitonic nature of three lowest lying

  9. Observation and applications of single-electron charge signals in the XENON100 experiment

    NARCIS (Netherlands)

    Aprile, E.; et al., [Unknown; Alfonsi, M.; Colijn, A.P.; Decowski, M.P.

    2014-01-01

    The XENON100 dark matter experiment uses liquid xenon in a time projection chamber (TPC) to measure xenon nuclear recoils resulting from the scattering of dark matter weakly interacting massive particles (WIMPs). In this paper, we report the observation of single-electron charge signals which are

  10. Modulation and Control of Charge Transport Through Single-Molecule Junctions.

    Science.gov (United States)

    Wang, Kun; Xu, Bingqian

    2017-02-01

    The ability to modulate and control charge transport though single-molecule junction devices is crucial to achieving the ultimate goal of molecular electronics: constructing real-world-applicable electronic components from single molecules. This review aims to highlight the progress made in single-molecule electronics, emphasizing the development of molecular junction electronics in recent years. Among many techniques that attempt to wire a molecule to metallic electrodes, the single-molecule break junction (SMBJ) technique is one of the most reliable and tunable experimental platforms for achieving metal-molecule-metal configurations. It also provides great freedom to tune charge transport through the junction. Soon after the SMBJ technique was introduced, it was extensively used to measure the conductances of individual molecules; however, different conductances were obtained for the same molecule, and it proved difficult to interpret this wide distribution of experimental data. This phenomenon was later found to be mainly due to a lack of precise experimental control and advanced data analysis methods. In recent years, researchers have directed considerable effort into advancing the SMBJ technique by gaining a deeper physical understanding of charge transport through single molecules and thus enhancing its potential applicability in functional molecular-scale electronic devices, such as molecular diodes and molecular transistors. In parallel with that research, novel data analysis methods and approaches that enable the discovery of hidden yet important features in the data are being developed. This review discusses various aspects of molecular junction electronics, from the initial goal of molecular electronics, the development of experimental techniques for creating single-molecule junctions and determining single-molecule conductance, to the characterization of functional current-voltage features and the investigation of physical properties other than charge

  11. An instrument for charge measurement due to a single collision between two spherical particles.

    Science.gov (United States)

    Xie, L; Bao, N; Jiang, Y; Han, K; Zhou, J

    2016-01-01

    It universally exists in moving particular systems that particles can be electrified, in which the particles are chemically identical, just as toner particles, coal dust, and pharmaceutical powders. However, owing to the limit of experimental instruments, so far, there are yet no experiments to illustrate whether a particle can be electrified due to a single collision between two spherical particles, and there are also no experiments to measure the charge carried by a single particle due to a single collision between two particles. So we have developed an instrument for charge measurement due to a single collision between two spheres. The instrument consists of two-sphere collision device, collision charge measurement apparatus, and particles' trajectory tracking system. By using this instrument, we can investigate the collision contact electrification due to a single collision between two spheres and simultaneously record the moving trajectories of spheres after the collision to calculate the rebound angles to identify the contribution of the triboelectrification due to the rubbing between the contact surfaces and the collision contact electrification due to the normal pressure between the contact surfaces.

  12. Calculations of Q values in single- and double-charge-transfer collisions of highly charged ions with atoms

    International Nuclear Information System (INIS)

    Chen, Z.; Lin, C.D.; Toshima, N.

    1994-01-01

    Close-coupling calculations are carried out for the Q values for electron capture processes in collisions of multiply charged ions with atoms over a broad range of energies. For single-capture processes the results for N 7+ +He and O 8+ +He collisions are in good agreement with the experimental data of Wu et al. [preceding paper, Phys. Rev. A 50, 502 (1994)]. To compare with the experimental Q values for the transfer ionization (TI) and the true double-capture (TDC) processes, an independent-electron model was used to calculate double-electron-capture cross sections. By combining with the calculated average fluorescence yields, the theoretical Q values for TI and TDC processes are also found to be in fair agreement with the experimental data. We also compared the Q values calculated by the close-coupling method and by the classical-trajectory Monte Carlo method

  13. Algorithms for solving the single-sink fixed-charge transportation problem

    DEFF Research Database (Denmark)

    Klose, Andreas

    2006-01-01

    The single-sink fixed-charge transportation problem is an important subproblem of the fixed-charge transportation problem. Just a few methods have been proposed in the literature to solve this problem. In this paper, solution approaches based on dynamic programming and implicit enumeration...... are revisited. It is shown how the problem size as well as the search space of a recently published dynamic programming method can be reduced by exploiting reduced cost information. Additionally, a further implicit enumeration approach relying on solution concepts for the binary knapsack problem is introduced...

  14. Charge calculation studies done on a single walled carbon nanotube using MOPAC

    Science.gov (United States)

    Negi, S.; Bhartiya, Vivek Kumar; Chaturvedi, S.

    2018-04-01

    Dipole symmetry of induced charges on DWNTs are required for their application as a nanomotor. Earlier a molecular dynamics analysis was performed for a double-walled carbon-nanotube based motor driven by an externally applied sinusoidally varying electric field. One of the ways to get such a system is chemical or end functionalization, which promises to accomplish this specific and rare configuration of the induced charges on the surface of the carbon nanotube (CNT). CNTs are also a promising system for attaching biomolecules for bio-related applications. In an earlier work, ab initio calculations were done to study the electronic and structural properties of the groups -COOH, -OH, -NH2 and -CONH2 functionalized to an (8, 0) SWNT. The systems were shown to have a very stable interaction with the CNTs. The exterior surface of the SWNT is found to be reactive to NH2 (amidogen). In this work, charge calculations are done on a CNT using MOPAC, which is a semi empirical quantum chemistry software package. As a first step, we calculate the effect of NH2 functionalization to a (5,0) SWNT of infinite length. The symmetric charge distribution of the bare SWNT is observed to be disturbed on addition of a single NH2 in the close proximity of the SWNT. A net positive and opposite charge is observed to be induced on the opposite sides of the nanotube circumference, which is, in turn, imperative for the nanomotor applications. The minimum and maximum value of the charge on any atom is observed to increase from - 0.3 to 0.6 and from - 0.3 to - 1.8 electronic charge as compared to the bare SWNT. This fluctuation of the surface charge to larger values than bare CNT, can be attributed to the coulomb repulsion between NH2 and the rest of the charge on the surface which results into minimizing the total energy of the system. No such opposite polarity of charges are observed on adding NH2 to each ring of the SWNT implying addition of a single amidogen to be the most appropriate

  15. Charge-odd and single-spin effects in two pion production in ep bar collisions

    International Nuclear Information System (INIS)

    Galynskij, M.V.; Kuraev, E.A.; Shajkhatdenov, B.G.; Ratcliffe, P.G.

    2000-01-01

    We consider two-photon and Bremsstrahlung mechanisms for the production of two charged pions in high-energy electron (proton) scattering off a transversely polarised proton. Interference between the relevant amplitudes generates a charge-odd contribution to the cross section for the process. In a kinematics with a jet moving along electron spin-independent part may be used for determination of phase differences for pion-pion scattering in the states with orbital momentum 0 or 2 and 1 whereas in a kinematics with a jet moving along proton spin-dependent part may be used to explain the experimental data for single-spin correlations in the production of negatively charged pions. We also discuss the backgrounds and estimate the accuracy of the results at less than 10% level. In addition simplified formulae derived for specific kinematics, with small total transverse pion momentum, are given

  16. Investigation of charge multiplication in single crystalline CVD diamond particle detectors

    Energy Technology Data Exchange (ETDEWEB)

    Muškinja, M.; Cindro, V.; Gorišek, A. [Jožef Stefan Institute, Jamova 39, SI-1000 Ljubljana (Slovenia); Kagan, H. [Department of Physics, Ohio State University (United States); Kramberger, G., E-mail: Gregor.Kramberger@ijs.si [Jožef Stefan Institute, Jamova 39, SI-1000 Ljubljana (Slovenia); Mandić, I. [Jožef Stefan Institute, Jamova 39, SI-1000 Ljubljana (Slovenia); Mikuž, M. [Jožef Stefan Institute, Jamova 39, SI-1000 Ljubljana (Slovenia); Faculty of Physics and Mathematics, University of Ljubljana (Slovenia); Phan, S.; Smith, D.S. [Department of Physics, Ohio State University (United States); Zavrtanik, M. [Jožef Stefan Institute, Jamova 39, SI-1000 Ljubljana (Slovenia)

    2017-01-01

    A special metallization pattern was created on a single crystalline diamond detector aimed at creating high enough electric field for impact ionization in the detector material. Electric field line focusing through electrode design and very high bias voltages were used to obtain high electric fields. Previous measurements and theoretical calculations indicated that drifting charge multiplication by impact ionization could take place. A large increase of induced charge was observed for the smallest dot electrode which points to charge multiplication while for the large dot and pad detector structure no such effect was observed. The evolution of induced currents was also monitored with the transient current technique. Induced current pulses with duration of order 1 μs were measured. The multiplication gain was found to depend on the particle rate.

  17. Sequencing of adenine in DNA by scanning tunneling microscopy

    Science.gov (United States)

    Tanaka, Hiroyuki; Taniguchi, Masateru

    2017-08-01

    The development of DNA sequencing technology utilizing the detection of a tunnel current is important for next-generation sequencer technologies based on single-molecule analysis technology. Using a scanning tunneling microscope, we previously reported that dI/dV measurements and dI/dV mapping revealed that the guanine base (purine base) of DNA adsorbed onto the Cu(111) surface has a characteristic peak at V s = -1.6 V. If, in addition to guanine, the other purine base of DNA, namely, adenine, can be distinguished, then by reading all the purine bases of each single strand of a DNA double helix, the entire base sequence of the original double helix can be determined due to the complementarity of the DNA base pair. Therefore, the ability to read adenine is important from the viewpoint of sequencing. Here, we report on the identification of adenine by STM topographic and spectroscopic measurements using a synthetic DNA oligomer and viral DNA.

  18. Spectroscopy of Charge Carriers and Traps in Field-Doped Single Crystal Organic Semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Xiaoyang

    2014-12-10

    The proposed research aims to achieve quantitative, molecular level understanding of charge carriers and traps in field-doped crystalline organic semiconductors via in situ linear and nonlinear optical spectroscopy, in conjunction with transport measurements and molecular/crystal engineering. Organic semiconductors are emerging as viable materials for low-cost electronics and optoelectronics, such as organic photovoltaics (OPV), organic field effect transistors (OFETs), and organic light emitting diodes (OLEDs). Despite extensive studies spanning many decades, a clear understanding of the nature of charge carriers in organic semiconductors is still lacking. It is generally appreciated that polaron formation and charge carrier trapping are two hallmarks associated with electrical transport in organic semiconductors; the former results from the low dielectric constants and weak intermolecular electronic overlap while the latter can be attributed to the prevalence of structural disorder. These properties have lead to the common observation of low charge carrier mobilities, e.g., in the range of 10-5 - 10-3 cm2/Vs, particularly at low carrier concentrations. However, there is also growing evidence that charge carrier mobility approaching those of inorganic semiconductors and metals can exist in some crystalline organic semiconductors, such as pentacene, tetracene and rubrene. A particularly striking example is single crystal rubrene (Figure 1), in which hole mobilities well above 10 cm2/Vs have been observed in OFETs operating at room temperature. Temperature dependent transport and spectroscopic measurements both revealed evidence of free carriers in rubrene. Outstanding questions are: what are the structural features and physical properties that make rubrene so unique? How do we establish fundamental design principles for the development of other organic semiconductors of high mobility? These questions are critically important but not comprehensive, as the nature of

  19. Surface structure modification of single crystal graphite after slow, highly charged ion irradiation

    Science.gov (United States)

    Alzaher, I.; Akcöltekin, S.; Ban-d'Etat, B.; Manil, B.; Dey, K. R.; Been, T.; Boduch, P.; Rothard, H.; Schleberger, M.; Lebius, H.

    2018-04-01

    Single crystal graphite was irradiated by slow, highly charged ions. The modification of the surface structure was studied by means of Low-Energy Electron Diffraction. The observed damage cross section increases with the potential energy, i.e. the charge state of the incident ion, at a constant kinetic energy. The potential energy is more efficient for the damage production than the kinetic energy by more than a factor of twenty. Comparison with earlier results hints to a strong link between early electron creation and later target atom rearrangement. With increasing ion fluence, the initially large-scale single crystal is first transformed into μ m-sized crystals, before complete amorphisation takes place.

  20. Transmission of Fast Highly Charged Ions through a Single Glass Macrocapillary and Polycarbonate Nanocapillary Foils

    Science.gov (United States)

    Ayyad, A. M.; Dassanayake, B. S.; Keerthisinghe, D.; DeSilva, G. G.; Elkafrawy, T.; Kayani, N.; Tanis, J. A.

    2012-11-01

    Transmission of 3 MeV protons and 16 MeV O5+ ions through a single glass macrocapillary and a polycarbonate nanocapillary foil has been investigated. Results show that 3 MeV protons transmit through the capillary and the foils with little or no energy loss, while 16 MeV O5+ ions show transmission through the capillary and the foil with energy losses that vary with the tilt angle, and there are also changes in the charge state.

  1. Adenine phosphoribosyltransferase-deficient Leishmania donovani

    International Nuclear Information System (INIS)

    Kaur, K.; Iovannisci, D.M.; Ullman, B.

    1986-01-01

    To elucidate the relative roles of two routes for adenine salvage, the authors use biochemical genetic approaches to isolate clonal strains of Leishmania donovani promasatigotes genetically deficient in APRTase activity. The studies suggest that the metabolic rate of adenine in these organisms is initiated by deamination. The radiolabel incorporation experiments and biochemical experiments are described in which the rate of uptake of radiolabelled purine nucleobases (C 14) was determined. Results are presented

  2. Single photon emission from charged excitons in CdTe/ZnTe quantum dots

    Science.gov (United States)

    Belyaev, K. G.; Rakhlin, M. V.; Sorokin, S. V.; Klimko, G. V.; Gronin, S. V.; Sedova, I. V.; Mukhin, I. S.; Ivanov, S. V.; Toropov, A. A.

    2017-11-01

    We report on micro-photoluminescence studies of individual self-organized CdTe/ZnTe quantum dots intended for single-photon-source applications in a visible spectral range. The quantum dots surface density below 1010 per cm2 was achieved by using a thermally activated regime of molecular beam epitaxy that allowed fabrication of etched mesa-structures containing only a few emitting quantum dots. The single photon emission with the autocorrelation function g(2)(0)<0.2 was detected and identified as recombination of charged excitons in the individual quantum dot.

  3. Optimized Charging Scheduling with Single Mobile Charger for Wireless Rechargeable Sensor Networks

    Directory of Open Access Journals (Sweden)

    Qihua Wang

    2017-11-01

    Full Text Available Due to the rapid development of wireless charging technology, the recharging issue in wireless rechargeable sensor network (WRSN has been a popular research problem in the past few years. The weakness of previous work is that charging route planning is not reasonable. In this work, a dynamic optimal scheduling scheme aiming to maximize the vacation time ratio of a single mobile changer for WRSN is proposed. In the proposed scheme, the wireless sensor network is divided into several sub-networks according to the initial topology of deployed sensor networks. After comprehensive analysis of energy states, working state and constraints for different sensor nodes in WRSN, we transform the optimized charging path problem of the whole network into the local optimization problem of the sub networks. The optimized charging path with respect to dynamic network topology in each sub-network is obtained by solving an optimization problem, and the lifetime of the deployed wireless sensor network can be prolonged. Simulation results show that the proposed scheme has good and reliable performance for a small wireless rechargeable sensor network.

  4. Single Molecule Spectroelectrochemistry of Interfacial Charge Transfer Dynamics In Hybrid Organic Solar Cell

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Shanlin [Univ. of Alabama, Tuscaloosa, AL (United States)

    2014-11-16

    Our research under support of this DOE grant is focused on applied and fundamental aspects of model organic solar cell systems. Major accomplishments are: 1) we developed a spectroelectorchemistry technique of single molecule single nanoparticle method to study charge transfer between conjugated polymers and semiconductor at the single molecule level. The fluorescence of individual fluorescent polymers at semiconductor surfaces was shown to exhibit blinking behavior compared to molecules on glass substrates. Single molecule fluorescence excitation anisotropy measurements showed the conformation of the polymer molecules did not differ appreciably between glass and semiconductor substrates. The similarities in molecular conformation suggest that the observed differences in blinking activity are due to charge transfer between fluorescent polymer and semiconductor, which provides additional pathways between states of high and low fluorescence quantum efficiency. Similar spectroelectrochemistry work has been done for small organic dyes for understand their charge transfer dynamics on various substrates and electrochemical environments; 2) We developed a method of transferring semiconductor nanoparticles (NPs) and graphene oxide (GO) nanosheets into organic solvent for a potential electron acceptor in bulk heterojunction organic solar cells which employed polymer semiconductor as the electron donor. Electron transfer from the polymer semiconductor to semiconductor and GO in solutions and thin films was established through fluorescence spectroscopy and electroluminescence measurements. Solar cells containing these materials were constructed and evaluated using transient absorption spectroscopy and dynamic fluorescence techniques to understand the charge carrier generation and recombination events; 3) We invented a spectroelectorchemistry technique using light scattering and electroluminescence for rapid size determination and studying electrochemistry of single NPs in an

  5. Single-charge craters excavated during subsurface high-explosive experiments at Big Black Test Site, Mississippi

    International Nuclear Information System (INIS)

    Woodruff, W.R.; Bryan, J.B.

    1978-01-01

    Single-charge and row-charge subsurface cratering experiments were performed to learn how close-spacing enhances single-crater dimensions. Our first experimental phase established cratering curves for 60-lb charges of the chemical explosive. For the second phase, to be described in a subsequent report, the Row-cratering experiments were designed and executed. This data report contains excavated dimensions and auxiliary data for the single-charge cratering experiments. The dimensions for the row-charge experiments will be in the other report. Significant changes in the soil's water content appeared to cause a variability in the excavated dimensions. This variability clouded the interpretation and application of the cratering curves obtained

  6. Energetics and metastability of the adenine dication observed in proton-adenine collisions

    Science.gov (United States)

    Moretto-Capelle, Patrick; Le Padellec, Arnaud; Brière, Guillaume; Massou, Sophie; Franceries, Frédéric

    2007-12-01

    We present here a study that deals with the correlated fragmentation of a doubly charged adenine molecular target induced by a 100keV proton beam. We have elucidated part of the dissociation dynamics for several channels and have obtained the corresponding kinetic energy released values. We have extracted activation energies by combining our experimental data with computations using the ab initio GAMESS code. We have observed metastability patterns against fragmentation, for which we have extracted the temporal mechanism (one or two steps). Subsequently, we have obtained lifetimes in the 100-200ns range. In the simplest case of two-body fragmentation with the emission of mass 28, the determination of transition states and reaction paths has showed that emission of the H-C-N-H fragment is preferred to that of C -N-H2. From the calculated activation barriers and lifetimes, we have deduced an equivalent temperature of the dication that we have compared with the existing models.

  7. Inclusive photoproduction of single charged particles at high pT

    International Nuclear Information System (INIS)

    Apsimon, R.J.; Flower, P.S.; Hallewell, G.; Morris, J.A.G.; Morris, J.V.; Paterson, C.N.; Sharp, P.H.; Atkinson, M.; Brook, N.; Coyle, P.; Dickinson, B.; Donnachie, A.; Doyle, A.T.; Ellison, R.J.; Foster, J.M.; Hughes-Jones, R.E.; Ibbotson, M.; Kolya, S.D.; Lafferty, G.D.; McCann, H.; McManus, C.; Mercer, D.; Ottewell, P.J.; Reid, D.; Thompson, R.J.; Waterhouse, J.; Barberis, D.; Davenport, M.; Eades, J.; McClatchey, R.; Brodbeck, T.J.; Charity, T.; Clegg, A.B.; Henderson, R.C.W.; Hickman, M.T.; Keemer, N.R.; Newton, D.; O'Connor, A.; Wilson, G.W.; Danaher, S.; Galbraith, W.; Thacker, N.A.; Thompson, L.

    1989-01-01

    Single charged-particle inclusive cross sections for photon, pion and kaon beams on hydrogen at the CERN-SPS are presented as functions of p T and x F . Data cover the range 0.0 T F T < 1.6 GeV/c for the photon-induced data. Using the hadron-induced data to estimate the hadronic behaviour of the photon, the difference distributions and ratios of cross sections are a measure of the contribution of the point-like photon interactions. The data are compared with QCD calculations and show broadly similar features. (orig.)

  8. Charge transport across a single-Cooper-pair transistor coupled to a resonant transmission line

    Energy Technology Data Exchange (ETDEWEB)

    Leppaekangas, Juha [Institut fuer Theoretische Festkoerperphysik, Karlsruhe Institute of Technology, D-76128 Karlsruhe (Germany); Department of Physical Sciences, University of Oulu, FI-90014 Oulu (Finland); Pashkin, Yuri [NEC Nano Electronics Research Laboratories, RIKEN Advanced Science Institute, Tsukuba, Ibaraki 305-8501 (Japan); Thuneberg, Erkki [Department of Physical Sciences, University of Oulu, FI-90014 Oulu (Finland)

    2010-07-01

    We have investigated charge transport in ultrasmall superconducting single and double Josephson junctions coupled to a transmission-line resonator. The microstrip resonator is naturally formed by the on-chip leads and the sample holder. We observe equidistant peaks in the transport characteristics of both types of devices and attribute them to the process involving simultaneous tunneling of Cooper pairs and photon emission into the resonator. The experimental data is well reproduced with the orthodox model of Cooper pair tunneling that accounts for the microwave photon emission into the resonator.

  9. Charging a Capacitor from an External Fluctuating Potential using a Single Conical Nanopore

    Science.gov (United States)

    Gomez, Vicente; Ramirez, Patricio; Cervera, Javier; Nasir, Saima; Ali, Mubarak; Ensinger, Wolfgang; Mafe, Salvador

    2015-01-01

    We explore the electrical rectification of large amplitude fluctuating signals by an asymmetric nanostructure operating in aqueous solution. We show experimentally and theoretically that a load capacitor can be charged to voltages close to 1 V within a few minutes by converting zero time-average potentials of amplitudes in the range 0.5–3 V into average net currents using a single conical nanopore. This process suggests that significant energy conversion and storage from an electrically fluctuating environment is feasible with a nanoscale pore immersed in a liquid electrolyte solution, a system characteristic of bioelectronics interfaces, electrochemical cells, and nanoporous membranes. PMID:25830563

  10. Charging a capacitor from an external fluctuating potential using a single conical nanopore.

    Science.gov (United States)

    Gomez, Vicente; Ramirez, Patricio; Cervera, Javier; Nasir, Saima; Ali, Mubarak; Ensinger, Wolfgang; Mafe, Salvador

    2015-04-01

    We explore the electrical rectification of large amplitude fluctuating signals by an asymmetric nanostructure operating in aqueous solution. We show experimentally and theoretically that a load capacitor can be charged to voltages close to 1 V within a few minutes by converting zero time-average potentials of amplitudes in the range 0.5-3 V into average net currents using a single conical nanopore. This process suggests that significant energy conversion and storage from an electrically fluctuating environment is feasible with a nanoscale pore immersed in a liquid electrolyte solution, a system characteristic of bioelectronics interfaces, electrochemical cells, and nanoporous membranes.

  11. Deflection of high energy channeled charged particles by elastically bent silicon single crystals

    International Nuclear Information System (INIS)

    Gibson, W.M.; Kim, I.J.; Pisharodoy, M.; Salman, S.M.; Sun, C.R.; Wang, G.H.; Wijayawardana, R.; Forster, J.S.; Mitchell, I.V.; Baker, S.I.; Carrigan, R.A. Jr.; Toohig, T.E.; Avdeichikov, V.V.; Ellison, J.A.; Siffert, P.

    1984-01-01

    An experiment has been carried out to observe the deflection of charged particles by planar channeling in bent single crystals of silicon for protons with energy up to 180 GeV. Anomolous loss of particles from the center point of a three point bending apparatus was observed at high incident particle energy. This effect has been exploited to fashion a 'dechanneling spectrometer' to study dechanneling effects due to centripital displacement of channeled particle trajectories in a bent crystal. The bending losses generally conform to the predictions of calculations based on a classical model. (orig.)

  12. Electronic transport in single-helical protein molecules: Effects of multiple charge conduction pathways and helical symmetry

    Energy Technology Data Exchange (ETDEWEB)

    Kundu, Sourav, E-mail: sourav.kunduphy@gmail.com; Karmakar, S.N.

    2016-07-15

    We propose a tight-binding model to investigate electronic transport properties of single helical protein molecules incorporating both the helical symmetry and the possibility of multiple charge transfer pathways. Our study reveals that due to existence of both the multiple charge transfer pathways and helical symmetry, the transport properties are quite rigid under influence of environmental fluctuations which indicates that these biomolecules can serve as better alternatives in nanoelectronic devices than its other biological counterparts e.g., single-stranded DNA.

  13. Solving the Single-Sink, Fixed-Charge, Multiple-Choice Transportation Problem by Dynamic Programming

    DEFF Research Database (Denmark)

    Christensen, Tue; Andersen, Kim Allan; Klose, Andreas

    2013-01-01

    This paper considers a minimum-cost network flow problem in a bipartite graph with a single sink. The transportation costs exhibit a staircase cost structure because such types of transportation cost functions are often found in practice. We present a dynamic programming algorithm for solving...... this so-called single-sink, fixed-charge, multiple-choice transportation problem exactly. The method exploits heuristics and lower bounds to peg binary variables, improve bounds on flow variables, and reduce the state-space variable. In this way, the dynamic programming method is able to solve large...... instances with up to 10,000 nodes and 10 different transportation modes in a few seconds, much less time than required by a widely used mixed-integer programming solver and other methods proposed in the literature for this problem....

  14. The effects of two counterpropagating surface acoustic wave beams on single electron acoustic charge transport

    International Nuclear Information System (INIS)

    He Jianhong; Guo Huazhong; Song Li; Zhang Wei; Gao Jie; Lu Chuan

    2010-01-01

    We present a comprehensive study of the effects of two counterpropagating surface acoustic waves on the acoustoelectric current of single electron transport devices. A significant improvement in the accuracy of current quantization is achieved as a result of an additional surface acoustic wave beam. The experiments reveal the sinusoidally periodical modulation in the acoustoelectric current characteristic as a function of the relative phase of the two surface acoustic wave beams. Besides, by using standing surface acoustic waves, the acoustoelectric current is detected which we consider as the so-called anomalous acoustoelectric current produced by acoustic wave mechanical deformations. This kind current is contributed to one component of the acoustoelectric current in surface acoustic wave device, which could enable us to establish a more adequate description of acoustoelectric effects on single-electron acoustic charge transport.

  15. Persistent Charge-Density-Wave Order in Single-Layer TaSe2.

    Science.gov (United States)

    Ryu, Hyejin; Chen, Yi; Kim, Heejung; Tsai, Hsin-Zon; Tang, Shujie; Jiang, Juan; Liou, Franklin; Kahn, Salman; Jia, Caihong; Omrani, Arash A; Shim, Ji Hoon; Hussain, Zahid; Shen, Zhi-Xun; Kim, Kyoo; Min, Byung Il; Hwang, Choongyu; Crommie, Michael F; Mo, Sung-Kwan

    2018-02-14

    We present the electronic characterization of single-layer 1H-TaSe 2 grown by molecular beam epitaxy using a combined angle-resolved photoemission spectroscopy, scanning tunneling microscopy/spectroscopy, and density functional theory calculations. We demonstrate that 3 × 3 charge-density-wave (CDW) order persists despite distinct changes in the low energy electronic structure highlighted by the reduction in the number of bands crossing the Fermi energy and the corresponding modification of Fermi surface topology. Enhanced spin-orbit coupling and lattice distortion in the single-layer play a crucial role in the formation of CDW order. Our findings provide a deeper understanding of the nature of CDW order in the two-dimensional limit.

  16. SINGLE CHANNEL SEISMIC APPLICATION FOR GAS CHARGED SEDIMENT RECONNAISSANCE IN GEOHAZARD STUDY OF PORT CONSTRUCTION AT WETLAND AREA

    Directory of Open Access Journals (Sweden)

    Taufan Wiguna

    2016-10-01

    Full Text Available Gas charged sediment as a one of parameter for geohazard study in infrastructure especially in swamp area. Instability of sediment layer for exampel subsidence and landslide result in geohazard potention that caused by gas charged sediment. Seismic single channel can be used to identufy gas charged sediment location. Seabed morphology is collected from bathymetry and tidal survey. From seismic profile interpretation shows gas charged sediment indication in Line A and Line B. That indication emerged by presence of acoustic turbid zone and acoustic blanking. Line A and Line B location will be spotlight in next geotechnic port construction study.

  17. Spiro-OMeTAD single crystals: Remarkably enhanced charge-carrier transport via mesoscale ordering

    KAUST Repository

    Shi, Dong

    2016-04-15

    We report the crystal structure and hole-transport mechanism in spiro-OMeTAD [2,2′,7,7′-tetrakis(N,N-di-p-methoxyphenyl-amine)9,9′-spirobifluorene], the dominant hole-transporting material in perovskite and solid-state dye-sensitized solar cells. Despite spiro-OMeTAD’s paramount role in such devices, its crystal structure was unknown because of highly disordered solution-processed films; the hole-transport pathways remained ill-defined and the charge carrier mobilities were low, posing a major bottleneck for advancing cell efficiencies. We devised an antisolvent crystallization strategy to grow single crystals of spiro-OMeTAD, which allowed us to experimentally elucidate its molecular packing and transport properties. Electronic structure calculations enabled us to map spiro-OMeTAD’s intermolecular charge-hopping pathways. Promisingly, single-crystal mobilities were found to exceed their thin-film counterparts by three orders of magnitude. Our findings underscore mesoscale ordering as a key strategy to achieving breakthroughs in hole-transport material engineering of solar cells.

  18. The Fate of a Normal Human Cell Traversed by a Single Charged Particle

    Science.gov (United States)

    Fournier, C.; Zahnreich, S.; Kraft, D.; Friedrich, T.; Voss, K.-O.; Durante, M.; Ritter, S.

    2012-01-01

    The long-term “fate” of normal human cells after single hits of charged particles is one of the oldest unsolved issues in radiation protection and cellular radiobiology. Using a high-precision heavy-ion microbeam we could target normal human fibroblasts with exactly one or five carbon ions and measured the early cytogenetic damage and the late behaviour using single-cell cloning. Around 70% of the first cycle cells presented visible aberrations in mFISH after a single ion traversal, and about 5% of the cells were still able to form colonies. In one third of selected high-proliferative colonies we observed clonal (radiation-induced) aberrations. Terminal differentiation and markers of senescence (PCNA, p16) in the descendants of cells traversed by one carbon ion occurred earlier than in controls, but no evidence of radiation-induced chromosomal instability was found. We conclude that cells surviving single-ion traversal, often carrying clonal chromosome aberrations, undergo accelerated senescence but maintain chromosomal stability. PMID:22966418

  19. The Fate of a Normal Human Cell Traversed by a Single Charged Particle

    Science.gov (United States)

    Fournier, C.; Zahnreich, S.; Kraft, D.; Friedrich, T.; Voss, K.-O.; Durante, M.; Ritter, S.

    2012-09-01

    The long-term ``fate'' of normal human cells after single hits of charged particles is one of the oldest unsolved issues in radiation protection and cellular radiobiology. Using a high-precision heavy-ion microbeam we could target normal human fibroblasts with exactly one or five carbon ions and measured the early cytogenetic damage and the late behaviour using single-cell cloning. Around 70% of the first cycle cells presented visible aberrations in mFISH after a single ion traversal, and about 5% of the cells were still able to form colonies. In one third of selected high-proliferative colonies we observed clonal (radiation-induced) aberrations. Terminal differentiation and markers of senescence (PCNA, p16) in the descendants of cells traversed by one carbon ion occurred earlier than in controls, but no evidence of radiation-induced chromosomal instability was found. We conclude that cells surviving single-ion traversal, often carrying clonal chromosome aberrations, undergo accelerated senescence but maintain chromosomal stability.

  20. Direct Imaging of Highly Anisotropic Photogenerated Charge Separations on Different Facets of a Single BiVO4 Photocatalyst.

    Science.gov (United States)

    Zhu, Jian; Fan, Fengtao; Chen, Ruotian; An, Hongyu; Feng, Zhaochi; Li, Can

    2015-07-27

    Spatially resolved surface photovoltage spectroscopy (SRSPS) was employed to obtain direct evidence for highly anisotropic photogenerated charge separation on different facets of a single BiVO4 photocatalyst. Through the controlled synthesis of a single crystal with preferentially exposed {010} facets, highly anisotropic photogenerated hole transfer to the {011} facet of single BiVO4 crystals was observed. The surface photovoltage signal intensity on the {011} facet was 70 times stronger than that on the {010} facets. The influence of the built-in electric field in the space charge region of different facets on the anisotropic photoinduced charge transfer in a single semiconductor crystal is revealed. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Charge transfer dynamics from adsorbates to surfaces with single active electron and configuration interaction based approaches

    Energy Technology Data Exchange (ETDEWEB)

    Ramakrishnan, Raghunathan, E-mail: r.ramakrishnan@unibas.ch [Institute of Physical Chemistry, National Center for Computational Design and Discovery of Novel Materials (MARVEL), Department of Chemistry, University of Basel, Klingelbergstrasse 80, CH-4056 Basel (Switzerland); Nest, Mathias [Theoretische Chemie, Technische Universität München, Lichtenbergstr. 4, 85747 Garching (Germany)

    2015-01-13

    Highlights: • We model electron dynamics across cyano alkanethiolates attached to gold cluster. • We present electron transfer time scales from TD-DFT and TD-CI based simulations. • Both DFT and CI methods qualitatively predict the trend in time scales. • TD-CI predicts the experimental relative time scale very accurately. - Abstract: We employ wavepacket simulations based on many-body time-dependent configuration interaction (TD-CI), and single active electron theories, to predict the ultrafast molecule/metal electron transfer time scales, in cyano alkanethiolates bonded to model gold clusters. The initial states represent two excited states where a valence electron is promoted to one of the two virtual π{sup ∗} molecular orbitals localized on the cyanide fragment. The ratio of the two time scales indicate the efficiency of one charge transfer channel over the other. In both our one-and many-electron simulations, this ratio agree qualitatively with each other as well as with the previously reported experimental time scales (Blobner et al., 2012), measured for a macroscopic metal surface. We study the effect of cluster size and the description of electron correlation on the charge transfer process.

  2. Transverse target single-spin asymmetry in inclusive electroproduction of charged pions and kaons

    Energy Technology Data Exchange (ETDEWEB)

    Airapetian, A. [Giessen Univ. (Germany). 2. Physikalisches Inst.; Michigan Univ., Ann Arbor, MI (United States). Randall Laboratory of Physics; Akopov, N. [Yerevan Physics Institute (Argentina); Akopov, Z. [DESY Hamburg (Germany)] [and others; Collaboration: HERMES Collaboration

    2013-10-15

    Single-spin asymmetries were investigated in inclusive electroproduction of charged pions and kaons from transversely polarized protons at the HERMES experiment. The asymmetries were studied as a function of the azimuthal angle {psi} about the beam direction between the target-spin direction and the hadron production plane, the transverse hadron momentum P{sub T} relative to the direction of the incident beam, and the Feynman variable x{sub F}. The sin {psi} amplitudes are positive for {pi}{sup +} and K{sup +}, slightly negative for {pi}{sup -} consistent with zero for K{sup -}, with particular P{sub T} but weak x{sub F} dependences. Especially large asymmetries are observed for two small subsamples of events, where also the scattered electron was recorded by the spectrometer.

  3. Chemical properties of astatine positive single-charged ion in aqueous solutions

    International Nuclear Information System (INIS)

    Milanov, M.; Doberents, V.; Khalkin, V.A.; Marinov, A.

    1983-01-01

    The mobility of the oxidized astatine in solutions H(Na)ClO 4 (μ=0.4 M) - 1x10 -4 M K 2 Cr 2 O 7 has been measured at 25 deg C in the interval 0.63 -4 cm 2 V -1 s -1 , pH 0.63 Usub(c)=2.67x10 -4 cm 2 V -1 s -1 . The effect agrees with the opinion that a single-charged cation of astatine formed in acidic solutions is a strong aquacomplex ((Hsub(2)O)sub(x)At)sup(+) (x=1-2) (protonized hypoastatine acid). Deprotonization constant of this cation is Ksub(dp)=0.032+-0.005. Specific properties of the astatine cation are given. They can be explained, probability, through the peculiarities of its structure

  4. Effect of quenched disorder on charge-orbital-spin ordering in single-layer manganites

    International Nuclear Information System (INIS)

    Uchida, Masaya; Mathieu, Roland; He, Jinping; Kaneko, Yoshio; Tokura, Yoshinori; Asamitsu, Atsushi; Kumai, Reiji; Tomioka, Yasuhide; Matsui, Yoshio

    2006-01-01

    Structural and magnetic properties have been investigated for half-doped single-layer manganites RE 0.5 Sr 1.5 MnO 4 [RE=La, (La, Pr), Pr, Nd, Sm, and Eu]. Analyses of electron diffraction and ac susceptibility measurements have revealed that the long-range charge-orbital ordering (CO-OO) state as observed in La 0.5 Sr 1.5 MnO 4 is suppressed for the other materials: the CO-OO transition temperature, as well as the correlation length decreases with a decrease in the cation size of RE. Such a short-range CO-OO state shows a spin-glass behavior at low temperatures. A new electronic phase diagram is established with quenched disorder as the control parameter. (author)

  5. Single and double charge transfer in Be/sup 4+/+He collisions: A molecular (Feshbach) approach

    Energy Technology Data Exchange (ETDEWEB)

    Martin, F.; Riera, A.; Yaez, M.

    1986-12-01

    In recent articles, we pointed out the fundamental difference between the molecular treatment of processes involving a multicharged ion and hydrogen or helium atoms, which is the (formal) autoionizing character of the molecular channels, and we reported a (new) implementation of the Feshbach method to calculate the molecular energies and couplings. In the present work we use the wave functions calculated with this Feshbach method for the BeHe/sup 4+/ quasimolecule, introduce a common translation factor in the formalism, and calculate the single and double charge-exchange cross sections in Be/sup 4+/+He(1s/sup 2/) collisions for impact energies 0.2--20 keV/amu. The mechanisms of the processes are discussed in detail.

  6. Transverse target single-spin asymmetry in inclusive electroproduction of charged pions and kaons

    Energy Technology Data Exchange (ETDEWEB)

    Airapetian, A. [II. Physikalisches Institut, Justus-Liebig-Universität Gießen, 35392 Gießen (Germany); Randall Laboratory of Physics, University of Michigan, Ann Arbor, MI 48109-1040 (United States); Akopov, N. [Yerevan Physics Institute, 375036 Yerevan (Armenia); Akopov, Z. [DESY, 22603 Hamburg (Germany); Aschenauer, E.C. [DESY, 15738 Zeuthen (Germany); Augustyniak, W. [National Centre for Nuclear Research, 00-689 Warsaw (Poland); Avakian, R.; Avetissian, A. [Yerevan Physics Institute, 375036 Yerevan (Armenia); Avetisyan, E. [DESY, 22603 Hamburg (Germany); Belostotski, S. [K.P. Konstantinov Petersburg Nuclear Physics Institute, Gatchina, 188300 Leningrad Region (Russian Federation); Bianchi, N. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Frascati, 00044 Frascati (Italy); Blok, H.P. [National Institute for Subatomic Physics (Nikhef), 1009 DB Amsterdam (Netherlands); Department of Physics and Astronomy, VU University, 1081 HV Amsterdam (Netherlands); Borissov, A. [DESY, 22603 Hamburg (Germany); Bowles, J. [SUPA, School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ (United Kingdom); Bryzgalov, V. [Institute for High Energy Physics, Protvino, 142281 Moscow Region (Russian Federation); Burns, J. [SUPA, School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ (United Kingdom); Capiluppi, M. [Istituto Nazionale di Fisica Nucleare, Sezione di Ferrara and Dipartimento di Fisica e Scienze della Terra, Università di Ferrara, 44122 Ferrara (Italy); Capitani, G.P. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Frascati, 00044 Frascati (Italy); Cisbani, E. [Istituto Nazionale di Fisica Nucleare, Sezione di Roma, Gruppo Collegato Sanità and Istituto Superiore di Sanità, 00161 Roma (Italy); and others

    2014-01-20

    Single-spin asymmetries were investigated in inclusive electroproduction of charged pions and kaons from transversely polarized protons at the HERMES experiment. The asymmetries were studied as a function of the azimuthal angle ψ about the beam direction between the target-spin direction and the hadron production plane, the transverse hadron momentum P{sub T} relative to the direction of the incident beam, and the Feynman variable x{sub F}. The sin ψ amplitudes are positive for π{sup +} and K{sup +}, slightly negative for π{sup −} and consistent with zero for K{sup −}, with particular P{sub T} but weak x{sub F} dependences. Especially large asymmetries are observed for two small subsamples of events, where also the scattered electron was recorded by the spectrometer.

  7. Charging the quantum capacitance of graphene with a single biological ion channel.

    Science.gov (United States)

    Wang, Yung Yu; Pham, Ted D; Zand, Katayoun; Li, Jinfeng; Burke, Peter J

    2014-05-27

    The interaction of cell and organelle membranes (lipid bilayers) with nanoelectronics can enable new technologies to sense and measure electrophysiology in qualitatively new ways. To date, a variety of sensing devices have been demonstrated to measure membrane currents through macroscopic numbers of ion channels. However, nanoelectronic based sensing of single ion channel currents has been a challenge. Here, we report graphene-based field-effect transistors combined with supported lipid bilayers as a platform for measuring, for the first time, individual ion channel activity. We show that the supported lipid bilayers uniformly coat the single layer graphene surface, acting as a biomimetic barrier that insulates (both electrically and chemically) the graphene from the electrolyte environment. Upon introduction of pore-forming membrane proteins such as alamethicin and gramicidin A, current pulses are observed through the lipid bilayers from the graphene to the electrolyte, which charge the quantum capacitance of the graphene. This approach combines nanotechnology with electrophysiology to demonstrate qualitatively new ways of measuring ion channel currents.

  8. Cavity-Enhanced Real-Time Monitoring of Single-Charge Jumps at the Microsecond Time Scale

    Science.gov (United States)

    Arnold, C.; Loo, V.; Lemaître, A.; Sagnes, I.; Krebs, O.; Voisin, P.; Senellart, P.; Lanco, L.

    2014-04-01

    We use fast coherent reflectivity measurements, in a strongly coupled quantum dot micropillar device, to monitor in real time single-charge jumps at the microsecond time scale. Thanks to the strong enhancement of light-matter interaction inside the cavity, and to a close to shot-noise-limited detection setup, the measurement rate is 5 orders of magnitude faster than with previous optical experiments of direct single-charge sensing with quantum dots. The monitored transitions, identified at any given time with a less than 0.2% error probability, correspond to a carrier being captured and then released by a single material defect. This high-speed technique opens the way for the real-time monitoring of other rapid single quantum events, such as the quantum jumps of a single spin.

  9. Chiral separation of tedizolid using charge single isomer derivatives of cyclodextrins by capillary electrokinetic chromatography.

    Science.gov (United States)

    Michalska, Katarzyna; Gruba, Ewa; Cielecka-Piontek, Judyta; Bednarek, Elżbieta

    2016-02-20

    A method to enantioseparate tedizolid (TED), the second analogue after linezolid (LIN) in a truly new class of antibacterial agents, the oxazolidinones, was developed based on capillary electrokinetic chromatography using cyclodextrin as chiral pseudophase (CD-cEKC). The single isomer R-tedizolid possesses one chiral centre at C5 of the oxazolidinone ring, which is associated with the antibacterial activity of the drug. Tedizolid enantiomers are non-charged and therefore require the use of charged cyclodextrins (CCDs) as carrier hosts to achieve a velocity difference during migration. During method development, hydrophilic anionic single-isomer and moderately hydrophobic and hydrophobic cyclodextrins were tested, including heptakis-(2,3-dihydroxy-6-sulfo)-β-cyclodextrin (HS-β-CD), heptakis-(2,3-diacetyl-6-sulfo)-β-cyclodextrin (HDAS-β-CD), oktakis-(2,3-diacetyl-6-sulfo)-γ-cyclodextrin (ODAS-γ-CD) and heptakis-(2,3-dimethyl-6-sulfo)-β-cyclodextrin (HDMS-β-CD). Only CDs that have acetyl groups at the C2 and C3 positions with seven (HDAS-β-CD) or eight (ODAS-γ-CD) residues of glucopyranose units provided baseline separation of the tedizolid enantiomers with the addition of organic solvent. During the experiments, different organic solvents were tested, such as methanol, acetonitrile, tetrahydrofuran, which varied in their abilities to donate or accept protons. The best enantiomer separation results were obtained using the CD-cEKC method with 37.5mM HDAS-β-CD dissolved in 50mM formic buffer (pH 4.0) with the addition of acetonitrile (81.4:18.6, v/v) at 27ºC, normal polarity, and 12kV. Finally, the apparent binding constants for each enantiomer-HDAS-β-CD pair were calculated. Moreover, in order to evaluate the behaviour of TED and LIN enantiomers relative to chiral selector, enantioselective interactions towards the precursors of TED and LIN isomers were also investigated. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. Effective potentials for charge-helium and charge-singly-ionized helium interactions in a dense plasma

    Energy Technology Data Exchange (ETDEWEB)

    Ramazanov, T.S.; Amirov, S.M.; Moldabekov, Zh.A. [Institute for Experimental and Theoretical Physics, Al-Farabi Kazakh National University, Almaty (Kazakhstan)

    2016-06-15

    The effective electron (proton)-He and electron (proton)-He{sup +} screened pair interaction potentials arising as a result of partial screening of the helium nucleus field by bound electrons, taking into account both screening by free charged particles and quantum diffraction effect in dense plasmas were derived. The impact of quantum effects on screening was analyzed. It was shown that plasma polarization around the atom leads to the additional repulsion (attraction) between the electron (proton) and the helium atom. The method of constructing the full electron (proton)-He and electron (proton)-He{sup +} screened pair interaction potentials as the sum of the derived potentials with the polarization potential and exchange potential is discussed. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  11. Controlling charges distribution at the surface of a single GaN nanowire by in-situ strain

    Directory of Open Access Journals (Sweden)

    Xiao Chen

    2017-08-01

    Full Text Available Effect of the strain on the charge distribution at the surface of a GaN semiconductor nanowire (NW has been investigated inside transmission electron microscope (TEM by in-situ off-axis electron holography. The outer and inner surfaces of the NW bent axially under compression of two Au electrodes were differently strained, resulting in difference of their Fermi levels. Consequently, the free electrons flow from the high Fermi level to the low level until the two Fermi levels aligned in a line. The potential distributions induced by charge redistribution in the two vacuum sides of the bent NW were examined respectively, and the opposite nature of the bounded charges on the outer and inner surfaces of the bent NW was identified. The results provide experimental evidence that the charge distribution at the surfaces of a single GaN NW can be controlled by different strains created along the NW.

  12. Electrochemical behaviors and simultaneous determination of guanine and adenine based on graphene–ionic liquid–chitosan composite film modified glassy carbon electrode

    International Nuclear Information System (INIS)

    Niu Xiuli; Yang Wu; Ren Jie; Guo Hao; Long Shijia; Chen Jiaojiao; Gao Jinzhang

    2012-01-01

    Highlights: ► This work developed a novel electrochemical biosensors for guanine and adenine detection simultaneously. ► A disposable electrode based on graphene sheets, ionic liquid and chitosan was proposed. ► The presented method was also applied to simultaneous determination of guanine and adenine in denatured DNA samples with satisfying results. ► Easy fabrication, high sensitivity, excellent reproducibility and long-term stability. - Abstract: A graphene sheets (GS), ionic liquid (IL) and chitosan (CS) modified electrode was fabricated and the modified electrode displayed excellent electrochemical catalytic activities toward guanine and adenine. The transfer electron number (n) and the charge transfer coefficient (α) were calculated with the result as n = 2, α = 0.58 for guanine, and n = 2, α = 0.51 for adenine, which indicated the electrochemical oxidation of guanine and adenine on GS/IL/CS modified electrode was a two-electron and two-proton process. The oxidation overpotentials of guanine and adenine were decreased significantly compared with those obtained at the bare glassy carbon electrode and multi-walled carbon nanotubes modified electrode. The modified electrode exhibited good analytical performance and was successfully applied for individual and simultaneous determination of guanine and adenine. Low detection limits of 0.75 μM for guanine and 0.45 μM for adenine were obtained, with the linear calibration curves over the concentration range 2.5–150 μM and 1.5–350 μM, respectively. At the same time, the proposed method was successfully applied for the determination of guanine and adenine in denatured DNA samples with satisfying results. Moreover, the GS/IL/CS modified electrode exhibited good sensitivity, long-term stability and reproducibility for the determination of guanine and adenine.

  13. Charge enhancement of single-stranded DNA in negative electrospray ionization using the supercharging reagent meta-nitrobenzyl alcohol.

    Science.gov (United States)

    Brahim, Bessem; Alves, Sandra; Cole, Richard B; Tabet, Jean-Claude

    2013-12-01

    Charge enhancement of single-stranded oligonucleotide ions in negative ESI mode is investigated. The employed reagent, meta-nitrobenzyl alcohol (m-NBA), was found to improve total signal intensity (Itot), increase the highest observed charge states (zhigh), and raise the average charge states (zavg) of all tested oligonucleotides analyzed in negative ESI. To quantify these increases, signal enhancement ratios (SER1%) and charge enhancement coefficients (CEC1%) were introduced. The SER1%, (defined as the quotient of total oligonucleotide ion abundances with 1% m-NBA divided by total oligonucleotide abundance without m-NBA) was found to be greater than unity for every oligonucleotide tested. The CEC1% values (defined as the average charge state in the presence of 1% m-NBA minus the average charge state in the absence of m-NBA) were found to be uniformly positive. Upon close inspection, the degree of charge enhancement for longer oligonucleotides was found to be dependent upon thymine density (i.e., the number and the location of phospho-thymidine units). A correlation between the charge enhancement induced by the presence of m-NBA and the apparent gas-phase acidity (largely determined by the sequence of thymine units but also by the presence of protons on other nucleobases) of multiply deprotonated oligonucleotide species, was thus established. Ammonium cations appeared to be directly involved in the m-NBA supercharging mechanism, and their role seems to be consistent with previously postulated ESI mechanisms describing desorption/ionization of single-stranded DNA into the gas phase.

  14. Charge Enhancement of Single-Stranded DNA in Negative Electrospray Ionization Using the Supercharging Reagent Meta-nitrobenzyl Alcohol

    Science.gov (United States)

    Brahim, Bessem; Alves, Sandra; Cole, Richard B.; Tabet, Jean-Claude

    2013-12-01

    Charge enhancement of single-stranded oligonucleotide ions in negative ESI mode is investigated. The employed reagent, meta-nitrobenzyl alcohol (m-NBA), was found to improve total signal intensity (Itot), increase the highest observed charge states (zhigh), and raise the average charge states (zavg) of all tested oligonucleotides analyzed in negative ESI. To quantify these increases, signal enhancement ratios (SER1%) and charge enhancement coefficients (CEC1%) were introduced. The SER1%, (defined as the quotient of total oligonucleotide ion abundances with 1 % m-NBA divided by total oligonucleotide abundance without m-NBA) was found to be greater than unity for every oligonucleotide tested. The CEC1% values (defined as the average charge state in the presence of 1 % m-NBA minus the average charge state in the absence of m-NBA) were found to be uniformly positive. Upon close inspection, the degree of charge enhancement for longer oligonucleotides was found to be dependent upon thymine density (i.e., the number and the location of phospho-thymidine units). A correlation between the charge enhancement induced by the presence of m-NBA and the apparent gas-phase acidity (largely determined by the sequence of thymine units but also by the presence of protons on other nucleobases) of multiply deprotonated oligonucleotide species, was thus established. Ammonium cations appeared to be directly involved in the m-NBA supercharging mechanism, and their role seems to be consistent with previously postulated ESI mechanisms describing desorption/ionization of single-stranded DNA into the gas phase.

  15. A Single-Phase Transformerless Inverter With Charge Pump Circuit Concept for Grid-Tied PV Applications

    DEFF Research Database (Denmark)

    Ardashir, Jaber Fallah; Sabahi, Mehran; Hosseini, Seyed Hossein

    2017-01-01

    This paper proposes a new single-phase transformerless photovoltaic (PV) inverter for grid-tied PV systems. The topology is derived from the concept of a charge pump circuit in order to eliminate the leakage current. It is composed of four power switches, two diodes, two capacitors, and an LCL ou...

  16. Development of a Charged Particle Microbeam for Single-Particle Subcellular Irradiations at the MIT Laboratory for Accelerator Beam Application

    International Nuclear Information System (INIS)

    Yanch, Jacquelyn C.

    2004-01-01

    The development of a charged particle microbeam for single particle, subcellular irradiations at the Massachusetts Institute of Technology Laboratory for Accelerator Beam Applications (MIT LABA) was initiated under this NEER aeard. The Microbeam apparatus makes use of a pre-existing electrostatic accelerator with a horizontal beam tube

  17. Influence of Magnetic Microparticles Isolation on Adenine Homonucleotides Structure

    Directory of Open Access Journals (Sweden)

    Monika Kremplova

    2014-02-01

    Full Text Available The electroactivity of purine and pyrimidine bases is the most important property of nucleic acids that is very useful for determining oligonucleotides using square wave voltammetry. This study was focused on the electrochemical behavior of adenine-containing oligonucleotides before and after their isolation using paramagnetic particles. Two peaks were detected—peak A related to the reduction of adenine base and another peak B involved in the interactions between individual adenine strands and contributes to the formation of various spatial structures. The influence of the number of adenine bases in the strand in the isolation process using paramagnetic particles was investigated too.

  18. Hydrolytic cleavage of N-6-substituted adenine derivatives by eukaryotic adenine and adenosine deaminases

    Czech Academy of Sciences Publication Activity Database

    Pospíšilová, H.; Šebela, M.; Novák, Ondřej; Frébort, I.

    2008-01-01

    Roč. 28, č. 6 (2008), s. 335-347 ISSN 0144-8463 R&D Projects: GA ČR(CZ) GA522/06/0022 Institutional research plan: CEZ:AV0Z50380511 Keywords : adenine deaminase * adenosine deaminase (ADA) * aminohydrolase Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.525, year: 2008

  19. Twisted intra-molecular charge transfer investigations of semiorganic triglycine phosphate single crystal for non linear optical applications

    Science.gov (United States)

    Meera, M. R.; Joselin Beaula, T.; Rayar, S. L.; Bena Jothy, V.

    2017-09-01

    NLO materials are gaining importance in technologies such as optical communication, optical computing and dynamic image processing. Many NLO crystals grown by mixing amino acids with various organic and inorganic acids have been reported in the literature. Hence, glycine mixed semi-organic material will be of special interest as a fundamental building block to develop many complex crystals with improved NLO properties. A semi organic Single crystal of Triglycine Phosphate (TGP) which was grown and spectral analysis have been using FTIR and Raman spectral analysis. Natural Bond Orbital Analysis and the atomic natural charges are also predicted. HOMO LUMO energy gap value suggests the possibility of charge transfer within the molecule.

  20. Transparent Flash Memory using Single Ta2O5 Layer for both Charge Trapping and Tunneling Dielectrics

    KAUST Repository

    Hota, Mrinal Kanti

    2017-06-08

    We report reproducible multibit transparent flash memory in which a single solution-derived Ta2O5 layer is used simultaneously as charge trapping and tunneling layer. This is different from conventional flash cells, where two different dielectric layers are typically used. Under optimized programming/erasing operations, the memory device shows excellent programmable memory characteristics with a maximum memory window of ~10 V. Moreover, the flash memory device shows a stable 2-bit memory performance, good reliability, including data retention for more than 104 sec and endurance performance for more than 100 cycles. The use of a common charge trapping and tunneling layer can simplify advanced flash memory fabrication.

  1. Charge integration successive approximation analog-to-digital converter for focal plane applications using a single amplifier

    Science.gov (United States)

    Zhou, Zhimin (Inventor); Pain, Bedabrata (Inventor)

    1999-01-01

    An analog-to-digital converter for on-chip focal-plane image sensor applications. The analog-to-digital converter utilizes a single charge integrating amplifier in a charge balancing architecture to implement successive approximation analog-to-digital conversion. This design requires minimal chip area and has high speed and low power dissipation for operation in the 2-10 bit range. The invention is particularly well suited to CMOS on-chip applications requiring many analog-to-digital converters, such as column-parallel focal-plane architectures.

  2. Measurement of Muon Neutrino Charged Current Single $\\pi^0$ Production on Hydrocarbon using MINERvA

    Energy Technology Data Exchange (ETDEWEB)

    Altinok, Ozgur [Tufts Univ., Medford, MA (United States)

    2017-01-01

    A sample of charged-current single pion production events for the semi- exclusive channel νµ + CH → µ-π0 + nucleon(s) has been obtained using neutrino exposures of the MINERvA detector. Differential cross sections for muon momentum, muon production angle, pion momentum, pion production angle, and four-momentum transfer square Q2 are reported and are compared to a GENIE-based simulation. The cross section versus neutrino energy is also re- ported. The effects of pion final-state interactions on these cross sections are investigated. The effect of baryon resonance suppression at low Q2 is examined and an event re-weight used by two previous experiments is shown to improve the data versus simulation agreement. The differential cross sections for Q2 for Eν < 4.0 GeV and Eν ≥ 4.0 GeV are examined and the shapes of these distributions are compared to those from the experiment’s $\\bar{v}$µ-CC (π0) measurement. The polarization of the pπ0 system is measured and compared to the simulation predictions. The hadronic invariant mass W distribution is examined for evidence of resonance content, and a search is reported for evidence of a two-particle two-hole (2p2h) contribution. All of the differential cross-section measurements of this Thesis are compared with published MINERvA measurements for νµ-CC (π+) and \\bar{v}$µ-CC (π0) processes.

  3. Communication: Site-selective bond excision of adenine upon electron transfer

    Science.gov (United States)

    Cunha, T.; Mendes, M.; Ferreira da Silva, F.; Eden, S.; García, G.; Limão-Vieira, P.

    2018-01-01

    This work demonstrates that selective excision of hydrogen atoms at a particular site of the DNA base adenine can be achieved in collisions with electronegative atoms by controlling the impact energy. The result is based on analysing the time-of-flight mass spectra yields of potassium collisions with a series of labeled adenine derivatives. The production of dehydrogenated parent anions is consistent with neutral H loss either from selective breaking of C-H or N-H bonds. These unprecedented results open up a new methodology in charge transfer collisions that can initiate selective reactivity as a key process in chemical reactions that are dominant in different areas of science and technology.

  4. Spectroscopy of Charge Carriers and Traps in Field-Doped Single Crystal Organic Semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Xiaoyang [Columbia Univ., New York, NY (United States); Frisbie, Daniel [Univ. of Minnesota, Minneapolis, MN (United States)

    2017-03-31

    The proposed research aims to achieve quantitative, molecular level understanding of charge carriers and traps in field-doped crystalline organic semiconductors via in situ linear and nonlinear optical spectroscopy, in conjunction with transport measurements and molecular/crystal engineering.

  5. Ionization in matrix-assisted laser desorption/ionization: singly charged molecular ions are the lucky survivors.

    Science.gov (United States)

    Karas, M; Glückmann, M; Schäfer, J

    2000-01-01

    A new model for the ionization processes in UV matrix-assisted laser desorption/ionization (MALDI) which accounts for the major phenomena observed is presented and discussed. The model retains elements of earlier approaches, such as photoionization and photochemical reactions, but it redefines these in the light of new working questions, most importantly why only singly charged ions are detected. Based on experimental evidence, the formation of singly and multiply charged clusters by a deficiency/excess of ions and also by photoionization and subsequent photochemical processes is pointed out to be the major ionization processes, which typically occur in parallel. The generation of electrons and their partial loss into the surrounding vacuum and solid, on the one hand, results in a positively charged ion-neutral plume facilitating a high overall ionization yield. On the other hand, these electrons, and also the large excess of protonated matrix ions in the negative ion mode, induce effective ion reneutralization in the plume. These neutralization processes are most effective for the highly charged cluster ions initially formed. Their fragmentation behaviour is evidenced in fast metastable fragmentation characteristics and agrees well with an electron capture dissociation mechanism and the enthalpy transfer upon neutralization forms the rationale for the prominent fragmentation and intense chemical noise accompanying successful MALDI. Within the course of the paper, cross-correlations with other desorption/ionization techniques and with earlier discussions on their mechanisms are drawn. Copyright 2000 John Wiley & Sons, Ltd.

  6. Effect of body biasing on single-event induced charge collection in deep N-well technology

    International Nuclear Information System (INIS)

    Ding Yi; Hu Jian-Guo; Tan Hong-Zhou; Qin Jun-Rui

    2015-01-01

    As the device size decreases, the soft error induced by space ions is becoming a great concern for the reliability of integrated circuits (ICs). At present, the body biasing technique is widely used in highly scaled technologies. In the paper, using the three-dimensional technology computer-aided design (TCAD) simulation, we analyze the effect of the body biasing on the single-event charge collection in deep N-well technology. Our simulation results show that the body biasing mainly affects the behavior of the source, and the effect of body biasing on the charge collection for the nMOSFET and pMOSFET is quite different. For the nMOSFET, the RBB will increase the charge collection, while the FBB will reduce the charge collection. For the pMOSFET, the effect of RBB on the SET pulse width is small, while the FBB has an adverse effect. Moreover, the differenceof the effect of body biasing on the charge collection is compared in deep N-well and twin well. (paper)

  7. The associated charged particle multiplicity of high-p/sub T/ pi /sup 0/ and single-photon events

    CERN Document Server

    Diakonou, M; Albrow, M G; Almehed, S; Benary, O; Bøggild, H; Botner, O; Cnops, A M; Cockerill, D J A; Dagan, S; Dahl-Jensen, Erik; Dahl-Jensen, I; Damgaard, G; Fabjan, Christian Wolfgang; Filippas-Tassos, A; Fokitis, E; Fowler, E C; Hallgren, A; Hansen, K H; Henning, S; Hood, D M; Hooper, J; Jarlskog, G; Karpathopoulos, S; Killian, T; Kourkoumelis, C; Kreisler, M; Lissauer, D; Lörstad, B; Ludlam, T; Mannelli, I; McCubbin, N A; Melin, A; Mjörnmark, U; Møller, R; Molzon, W; Mouzourakis, P; Nielsen, B S; Nielsen, S O; Nilsson, A; Oren, Y; Palmer, R B; Rahm, David Charles; Rehak, P; Resvanis, L K; Rosselt, L; Schistad, B; Stumer, I; Svensson, L; von Dardel, Guy F; Willis, W J

    1980-01-01

    The associated charged particle multiplicities of high-p/sub T/ pi /sup 0/ and single-photon events were measured at the CERN intersecting storage rings using lead/liquid-argon calorimeters and a scintillation counter array placed around the intersection region. The average multiplicity on the trigger side for the single-photon events was found to be significantly lower than that for the pi /sup 0/ events. The away-side multiplicity for both pi /sup 0/ and single- photon events increases with the trigger particle p/sub T/, but, at a fixed p/sub T/, the direct photon sample was found to have a slightly lower average multiplicity. The differences in the event structure can be explained if a large fraction of the single photons are produced via qg to gamma q constituent scattering. (16 refs).

  8. Interaction of singly and multiply charged ions with a lithium-fluoride surface

    CERN Document Server

    Wirtz, L

    2001-01-01

    Charge transfer between slow ions and an ionic crystal surface still poses a considerable challenge to theory due to the intrinsic many-body character of the system. For the neutralization of multiply charged ions in front of metal surfaces, the Classical Over the Barrier (COB) model is a widely used tool. We present an extension of this model to ionic crystal surfaces where the localization of valence electrons at the anion sites and the lack of cylindrical symmetry of the ion-surface system impede a simple analytical estimate of electron transfer rates. We use a classical trajectory Monte Carlo approach to calculate electron transfer rates for different charge states of the projectile ion. With these rates we perform a Monte Carlo simulation of the neutralization of slow Ne10+ ions in vertical incidence on an LiF surface. Capture of one or several electrons may lead to a local positive charge up of the surface. The projectile dynamics depends on the balance between the repulsion due to this charge and the a...

  9. Detection of singly- and doubly-charged quaternary ammonium drugs in equine urine by liquid chromatography/tandem mass spectrometry.

    Science.gov (United States)

    Ho, Emmie N M; Kwok, W H; Wong, April S Y; Wan, Terence S M

    2012-01-13

    Quaternary ammonium drugs (QADs) are anticholinergic agents some of which are known to have been abused or misused in equine sports. A recent review of literature shows that the screening methods reported thus far for QADs mainly cover singly-charged QADs. Doubly-charged QADs are extremely polar substances which are difficult to be extracted and poorly retained on reversed-phase columns. It would be ideal if a comprehensive method can be developed which can detect both singly- and doubly-charged QADs. This paper describes an efficient liquid chromatography/tandem mass spectrometry (LC/MS/MS) method for the simultaneous detection and confirmation of 38 singly- and doubly-charged QADs at sub-parts-per-billion (ppb) to low-ppb levels in equine urine after solid-phase extraction. Quaternary ammonium drugs were extracted from equine urine by solid-phase extraction (SPE) using an ISOLUTE(®) CBA SPE column and analysed by LC/MS/MS in the positive electrospray ionisation mode. Separation of the 38 QADs was achieved on a polar group embedded C18 LC column with a mixture of aqueous ammonium formate (pH 3.0, 10 mM) and acetonitrile as the mobile phase. Detection and confirmation of the 38 QADs at sub-ppb to low-ppb levels in equine urine could be achieved within 16 min using selected reaction monitoring (SRM). Matrix interference of the target transitions at the expected retention times was not observed. Other method validation data, including precision and recovery, were acceptable. The method was successfully applied to the analyses of drug-administration samples. Copyright © 2011 Elsevier B.V. All rights reserved.

  10. Realization of a Cascaded Quantum System: Heralded Absorption of a Single Photon Qubit by a Single-Electron Charged Quantum Dot.

    Science.gov (United States)

    Delteil, Aymeric; Sun, Zhe; Fält, Stefan; Imamoğlu, Atac

    2017-04-28

    Photonic losses pose a major limitation for the implementation of a quantum state transfer between nodes of a quantum network. A measurement that heralds a successful transfer without revealing any information about the qubit may alleviate this limitation. Here, we demonstrate the heralded absorption of a single photonic qubit, generated by a single neutral quantum dot, by a single-electron charged quantum dot that is located 5 m away. The transfer of quantum information to the spin degree of freedom takes place upon the emission of a photon; for a properly chosen or prepared quantum dot, the detection of this photon yields no information about the qubit. We show that this process can be combined with local operations optically performed on the destination node by measuring classical correlations between the absorbed photon color and the final state of the electron spin. Our work suggests alternative avenues for the realization of quantum information protocols based on cascaded quantum systems.

  11. Nanometer-size surface modification produced by single, low energy, highly charged ions

    International Nuclear Information System (INIS)

    Stockli, M.P.

    1994-01-01

    Atomically flat surfaces of insulators have been bombarded with low energy, highly charged ions to search for nanometer-size surface modifications. It is expected that the high electron deficiency of highly charged ions will capture and/or remove many of the insulator's localized electrons when impacting on an insulating surface. The resulting local electron deficiency is expected to locally disintegrate the insulator through a open-quotes Coulomb explosionclose quotes forming nanometer-size craters. Xe ions with charge states between 10+ and 45+ and kinetic energies between 0 and 10 keV/q were obtained from the KSU-CRYEBIS, a CRYogenic Electron Beam Ion Source and directed onto various insulating materials. Mica was favored as target material as atomically flat surfaces can be obtained reliably through cleaving. However, the authors observations with an atomic force microscope have shown that mica tends to defoliate locally rather than disintegrate, most likely due to the small binding forces between adjacent layers. So far the authors measurements indicate that each ion produces one blister if the charge state is sufficiently high. The blistering does not seem to depend very much on the kinetic energy of the ions

  12. Long-Lived Charge Separation at Heterojunctions between Semiconducting Single-Walled Carbon Nanotubes and Perylene Diimide Electron Acceptors

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Hyun Suk [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Arias, Dylan H [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Blackburn, Jeffrey L [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Sisto, Thomas J. [Columbia University; Peurifoy, Samuel [Columbia University; Zhang, Boyuan [Columbia University; Nuckolls, Colin [Columbia University

    2018-04-13

    Nonfullerene electron acceptors have facilitated a recent surge in the efficiencies of organic solar cells, although fundamental studies of the nature of exciton dissociation at interfaces with nonfullerene electron acceptors are still relatively sparse. Semiconducting single-walled carbon nanotubes (s-SWCNTs), unique one-dimensional electron donors with molecule-like absorption and highly mobile charges, provide a model system for studying interfacial exciton dissociation. Here, we investigate excited-state photodynamics at the heterojunction between (6,5) s-SWCNTs and two perylene diimide (PDI)-based electron acceptors. Each of the PDI-based acceptors, hPDI2-pyr-hPDI2 and Trip-hPDI2, is deposited onto (6,5) s-SWCNT films to form a heterojunction bilayer. Transient absorption measurements demonstrate that photoinduced hole/electron transfer occurs at the photoexcited bilayer interfaces, producing long-lived separated charges with lifetimes exceeding 1.0 us. Both exciton dissociation and charge recombination occur more slowly for the hPDI2-pyr-hPDI2 bilayer than for the Trip-hPDI2 bilayer. To explain such differences, we discuss the potential roles of the thermodynamic charge transfer driving force available at each interface and the different molecular structure and intermolecular interactions of PDI-based acceptors. Detailed photophysical analysis of these model systems can develop the fundamental understanding of exciton dissociation between organic electron donors and nonfullerene acceptors, which has not been systematically studied.

  13. Large-Scale Single Particle and Cell Trapping based on Rotating Electric Field Induced-Charge Electroosmosis.

    Science.gov (United States)

    Wu, Yupan; Ren, Yukun; Tao, Ye; Hou, Likai; Jiang, Hongyuan

    2016-12-06

    We propose a simple, inexpensive microfluidic chip for large-scale trapping of single particles and cells based on induced-charge electroosmosis in a rotating electric field (ROT-ICEO). A central floating electrode array, was placed in the center of the gap between four driving electrodes with a quadrature configuration and used to immobilize single particles or cells. Cells were trapped on the electrode array by the interaction between ROT-ICEO flow and buoyancy flow. We experimentally optimized the efficiency of trapping single particles by investigating important parameters like particle or cell density and electric potential. Experimental and numerical results showed good agreement. The operation of the chip was verified by trapping single polystyrene (PS) microspheres with diameters of 5 and 20 μm and single yeast cells. The highest single particle occupancy of 73% was obtained using a floating electrode array with a diameter of 20 μm with an amplitude voltage of 5 V and frequency of 10 kHz for PS microbeads with a 5-μm diameter and density of 800 particles/μL. The ROT-ICEO flow could hold cells against fluid flows with a rate of less than 0.45 μL/min. This novel, simple, robust method to trap single cells has enormous potential in genetic and metabolic engineering.

  14. Transparent Flash Memory Using Single Ta2O5Layer for Both Charge-Trapping and Tunneling Dielectrics.

    Science.gov (United States)

    Hota, Mrinal K; Alshammari, Fwzah H; Salama, Khaled N; Alshareef, Husam N

    2017-07-05

    We report reproducible multibit transparent flash memory in which a single solution-derived Ta 2 O 5 layer is used simultaneously as a charge-trapping layer and a tunneling layer. This is different from conventional flash memory cells where two different dielectric layers are typically used. Under optimized programming/erasing operations, the memory device shows excellent programmable memory characteristics with a maximum memory window of ∼10.7 V. Moreover, the flash memory device shows a stable 2-bit memory performance and good reliability, including data retention for more than 10 4 s and endurance performance for more than 100 cycles. The use of a common charge-trapping and tunneling layer can simplify the fabrication of advanced flash memories.

  15. Visualization of single-wall carbon nanotube (SWNT) networks in conductive polystyrene nanocomposites by charge contrast imaging

    International Nuclear Information System (INIS)

    Loos, Joachim; Alexeev, Alexander; Grossiord, Nadia; Koning, Cor E.; Regev, Oren

    2005-01-01

    The morphology of conductive nanocomposites consisting of low concentration of single-wall carbon nanotubes (SWNT) and polystyrene (PS) has been studied using atomic force microscopy (AFM), transmission electron microscopy (TEM) and, in particular, scanning electron microscopy (SEM). Application of charge contrast imaging in SEM allows visualization of the overall SWNT dispersion within the polymer matrix as well as the identification of individual or bundled SWNTs at high resolution. The contrast mechanism involved will be discussed. In conductive nanocomposites the SWNTs are homogeneously dispersed within the polymer matrix and form a network. Beside fairly straight SWNTs, strongly bended SWNTs have been observed. However, for samples with SWNT concentrations below the percolation threshold, the common overall charging behavior of an insulating material is observed preventing the detailed morphological investigation of the sample

  16. Analysis of some greedy algorithms for the single-sink fixed-charge transportation problem

    DEFF Research Database (Denmark)

    Görtz, Simon; Klose, Andreas

    2009-01-01

    -charge transportation problem. Nevertheless, just a few methods for solving this problem have been proposed in the literature. In this paper, some greedy heuristic solutions methods for the SSFCTP are investigated. It is shown that two greedy approaches for the SSFCTP known from the literature can be arbitrarily bad......, whereas an approximation algorithm proposed in the literature for the binary min-knapsack problem has a guaranteed worst case bound if adapted accordingly to the case of the SSFCTP....

  17. Single-hole spectral function and spin-charge separation in the t-J model

    Science.gov (United States)

    Mishchenko, A. S.; Prokof'ev, N. V.; Svistunov, B. V.

    2001-07-01

    Worm algorithm Monte Carlo simulations of the hole Green function with subsequent spectral analysis were performed for 0.1hole spectral function in the thermodynamic limit. Spectral analysis reveals a δ-function-sharp quasiparticle peak at the lower edge of the spectrum that is incompatible with the power-law singularity and thus rules out the possibility of spin-charge separation in this parameter range. Spectral continuum features two peaks separated by a gap ~4÷5 t.

  18. Single ion induced surface nanostructures: a comparison between slow highly charged and swift heavy ions.

    Science.gov (United States)

    Aumayr, Friedrich; Facsko, Stefan; El-Said, Ayman S; Trautmann, Christina; Schleberger, Marika

    2011-10-05

    This topical review focuses on recent advances in the understanding of the formation of surface nanostructures, an intriguing phenomenon in ion-surface interaction due to the impact of individual ions. In many solid targets, swift heavy ions produce narrow cylindrical tracks accompanied by the formation of a surface nanostructure. More recently, a similar nanometric surface effect has been revealed for the impact of individual, very slow but highly charged ions. While swift ions transfer their large kinetic energy to the target via ionization and electronic excitation processes (electronic stopping), slow highly charged ions produce surface structures due to potential energy deposited at the top surface layers. Despite the differences in primary excitation, the similarity between the nanostructures is striking and strongly points to a common mechanism related to the energy transfer from the electronic to the lattice system of the target. A comparison of surface structures induced by swift heavy ions and slow highly charged ions provides a valuable insight to better understand the formation mechanisms. © 2011 IOP Publishing Ltd

  19. Residue propensities, discrimination and binding site prediction of adenine and guanine phosphates

    Directory of Open Access Journals (Sweden)

    Ahmad Zulfiqar

    2011-05-01

    Full Text Available Abstract Background Adenine and guanine phosphates are involved in a number of biological processes such as cell signaling, metabolism and enzymatic cofactor functions. Binding sites in proteins for these ligands are often detected by looking for a previously known motif by alignment based search. This is likely to miss those where a similar binding site has not been previously characterized and when the binding sites do not follow the rule described by predefined motif. Also, it is intriguing how proteins select between adenine and guanine derivative with high specificity. Results Residue preferences for AMP, GMP, ADP, GDP, ATP and GTP have been investigated in details with additional comparison with cyclic variants cAMP and cGMP. We also attempt to predict residues interacting with these nucleotides using information derived from local sequence and evolutionary profiles. Results indicate that subtle differences exist between single residue preferences for specific nucleotides and taking neighbor environment and evolutionary context into account, successful models of their binding site prediction can be developed. Conclusion In this work, we explore how single amino acid propensities for these nucleotides play a role in the affinity and specificity of this set of nucleotides. This is expected to be helpful in identifying novel binding sites for adenine and guanine phosphates, especially when a known binding motif is not detectable.

  20. Investigation of electrically-active deep levels in single-crystalline diamond by particle-induced charge transient spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Kada, W., E-mail: kada.wataru@gunma-u.ac.jp [Faculty of Science and Technology, Gunma University, Kiryu, Gunma 376-8515 (Japan); Kambayashi, Y.; Ando, Y. [Faculty of Science and Technology, Gunma University, Kiryu, Gunma 376-8515 (Japan); Japan Atomic Energy Agency, Takasaki, Gunma 370-1292 (Japan); Onoda, S. [Japan Atomic Energy Agency, Takasaki, Gunma 370-1292 (Japan); Umezawa, H.; Mokuno, Y. [National Institute of Advanced Industrial Science and Technology (AIST), 1-8-31 Midorigaoka, Ikeda, Osaka 563-8577 (Japan); Shikata, S. [Kwansei Gakuin Univ., 2-1, Gakuen, Mita, Hyogo 669-1337 (Japan); Makino, T.; Koka, M. [Japan Atomic Energy Agency, Takasaki, Gunma 370-1292 (Japan); Hanaizumi, O. [Faculty of Science and Technology, Gunma University, Kiryu, Gunma 376-8515 (Japan); Kamiya, T.; Ohshima, T. [Japan Atomic Energy Agency, Takasaki, Gunma 370-1292 (Japan)

    2016-04-01

    To investigate electrically-active deep levels in high-resistivity single-crystalline diamond, particle-induced charge transient spectroscopy (QTS) techniques were performed using 5.5 MeV alpha particles and 9 MeV carbon focused microprobes. For unintentionally-doped (UID) chemical vapor deposition (CVD) diamond, deep levels with activation energies of 0.35 eV and 0.43 eV were detected which correspond to the activation energy of boron acceptors in diamond. The results suggested that alpha particle and heavy ion induced QTS techniques are the promising candidate for in-situ investigation of deep levels in high-resistivity semiconductors.

  1. Charge Dependence and Electric Quadrupole Effects on Single-Nucleon Removal in Relativistic and Intermediate Energy Nuclear Collisions

    Science.gov (United States)

    Norbury, John W.

    1992-01-01

    Single nucleon removal in relativistic and intermediate energy nucleus-nucleus collisions is studied using a generalization of Weizsacker-Williams theory that treats each electromagnetic multipole separately. Calculations are presented for electric dipole and quadrupole excitations and incorporate a realistic minimum impact parameter, Coulomb recoil corrections, and the uncertainties in the input photonuclear data. Discrepancies are discussed. The maximum quadrupole effect to be observed in future experiments is estimated and also an analysis of the charge dependence of the electromagnetic cross sections down to energies as low as 100 MeV/nucleon is made.

  2. Nicotinamide adenine dinucleotide biosynthesis promotes liver regeneration.

    Science.gov (United States)

    Mukherjee, Sarmistha; Chellappa, Karthikeyani; Moffitt, Andrea; Ndungu, Joan; Dellinger, Ryan W; Davis, James G; Agarwal, Beamon; Baur, Joseph A

    2017-02-01

    The regenerative capacity of the liver is essential for recovery from surgical resection or injuries induced by trauma or toxins. During liver regeneration, the concentration of nicotinamide adenine dinucleotide (NAD) falls, at least in part due to metabolic competition for precursors. To test whether NAD availability restricts the rate of liver regeneration, we supplied nicotinamide riboside (NR), an NAD precursor, in the drinking water of mice subjected to partial hepatectomy. NR increased DNA synthesis, mitotic index, and mass restoration in the regenerating livers. Intriguingly, NR also ameliorated the steatosis that normally accompanies liver regeneration. To distinguish the role of hepatocyte NAD levels from any systemic effects of NR, we generated mice overexpressing nicotinamide phosphoribosyltransferase, a rate-limiting enzyme for NAD synthesis, specifically in the liver. Nicotinamide phosphoribosyltransferase overexpressing mice were mildly hyperglycemic at baseline and, similar to mice treated with NR, exhibited enhanced liver regeneration and reduced steatosis following partial hepatectomy. Conversely, mice lacking nicotinamide phosphoribosyltransferase in hepatocytes exhibited impaired regenerative capacity that was completely rescued by administering NR. NAD availability is limiting during liver regeneration, and supplementation with precursors such as NR may be therapeutic in settings of acute liver injury. (Hepatology 2017;65:616-630). © 2016 by the American Association for the Study of Liver Diseases.

  3. Butyrate influences intracellular levels of adenine and adenine derivatives in the fungus Penicillium restrictum.

    Science.gov (United States)

    Zutz, Christoph; Chiang, Yi Ming; Faehnrich, Bettina; Bacher, Markus; Hellinger, Roland; Kluger, Bernhard; Wagner, Martin; Strauss, Joseph; Rychli, Kathrin

    2017-04-01

    Butyrate, a small fatty acid, has an important role in the colon of ruminants and mammalians including the inhibition of inflammation and the regulation of cell proliferation. There is also growing evidence that butyrate is influencing the histone structure in mammalian cells by inhibition of histone deacetylation. Butyrate shows furthermore an antimicrobial activity against fungi, yeast and bacteria, which is linked to its toxicity at a high concentration. In fungi there are indications that butyrate induces the production of secondary metabolites potentially via inhibition of histone deacetylases. However, information about the influence of butyrate on growth, primary metabolite production and metabolism, besides lipid catabolism, in fungi is scarce. We have identified the filamentous fungus Penicillium (P.) restrictum as a susceptible target for butyrate treatment in an antimicrobial activity screen. The antimicrobial activity was detected only in the mycelium of the butyrate treated culture. We investigated the effect of butyrate ranging from low (0.001mM) to high (30mM), potentially toxic, concentrations on biomass and antimicrobial activity. Butyrate at high concentrations (3 and 30mM) significantly reduced the fungal biomass. In contrast P. restrictum treated with 0.03mM of butyrate showed the highest antimicrobial activity. We isolated three antimicrobial active compounds, active against Staphylococcus aureus, from P. restrictum cellular extracts treated with butyrate: adenine, its derivate hypoxanthine and the nucleoside derivate adenosine. Production of all three compounds was increased at low butyrate concentrations. Furthermore we found that butyrate influences the intracellular level of the adenine nucleoside derivate cAMP, an important signalling molecule in fungi and various organisms. In conclusion butyrate treatment increases the intracellular levels of adenine and its respective derivatives. Copyright © 2017 Elsevier GmbH. All rights reserved.

  4. Minimizing the energy spread within a single bunch by shaping its charge distribution

    International Nuclear Information System (INIS)

    Loew, G.A.; Wang, J.W.

    1985-03-01

    It has been known for some time that partial compensation of the longitudinal wake field effects can be obtained for any bunch by placing it ahead of the accelerating crest (in space), thereby letting the positive rising sinusoidal field offset the negative beam loading field. The work presented in this paper shows that it is possible to obtain complete compensation, i.e., to reduce the energy spread essentially to zero by properly shaping the longitudinal charge distribution of the bunch and by placing it at the correct position on the wave. 3 refs., 5 figs., 3 tabs

  5. Search for the Single Production of Doubly-Charged Higgs Bosons and Constraints on their Couplings from Bhabha Scattering

    CERN Document Server

    Abbiendi, G; Akesson, P.F.; Alexander, G.; Allison, John; Amaral, P.; Anagnostou, G.; Anderson, K.J.; Arcelli, S.; Asai, S.; Axen, D.; Azuelos, G.; Bailey, I.; Barberio, E.; Barlow, R.J.; Batley, R.J.; Bechtle, P.; Behnke, T.; Bell, Kenneth Watson; Bell, P.J.; Bella, G.; Bellerive, A.; Benelli, G.; Bethke, S.; Biebel, O.; Boeriu, O.; Bock, P.; Boutemeur, M.; Braibant, S.; Brigliadori, L.; Brown, Robert M.; Buesser, K.; Burckhart, H.J.; Campana, S.; Carnegie, R.K.; Caron, B.; Carter, A.A.; Carter, J.R.; Chang, C.Y.; Charlton, David G.; Csilling, A.; Cuffiani, M.; Dado, S.; De Roeck, A.; De Wolf, E.A.; Desch, K.; Dienes, B.; Donkers, M.; Dubbert, J.; Duchovni, E.; Duckeck, G.; Duerdoth, I.P.; Etzion, E.; Fabbri, F.; Feld, L.; Ferrari, P.; Fiedler, F.; Fleck, I.; Ford, M.; Frey, A.; Furtjes, A.; Gagnon, P.; Gary, John William; Gaycken, G.; Geich-Gimbel, C.; Giacomelli, G.; Giacomelli, P.; Giunta, Marina; Goldberg, J.; Groll, M.; Gross, E.; Grunhaus, J.; Gruwe, M.; Gunther, P.O.; Gupta, A.; Hajdu, C.; Hamann, M.; Hanson, G.G.; Harder, K.; Harel, A.; Harin-Dirac, M.; Hauschild, M.; Hawkes, C.M.; Hawkings, R.; Hemingway, R.J.; Hensel, C.; Herten, G.; Heuer, R.D.; Hill, J.C.; Hoffman, Kara Dion; Horvath, D.; Igo-Kemenes, P.; Ishii, K.; Jeremie, H.; Jovanovic, P.; Junk, T.R.; Kanaya, N.; Kanzaki, J.; Karapetian, G.; Karlen, D.; Kawagoe, K.; Kawamoto, T.; Keeler, R.K.; Kellogg, R.G.; Kennedy, B.W.; Kim, D.H.; Klein, K.; Klier, A.; Kluth, S.; Kobayashi, T.; Kobel, M.; Komamiya, S.; Kormos, Laura L.; Kramer, T.; Krieger, P.; von Krogh, J.; Kruger, K.; Kuhl, T.; Kupper, M.; Lafferty, G.D.; Landsman, H.; Lanske, D.; Layter, J.G.; Leins, A.; Lellouch, D.; Lettso, J.; Levinson, L.; Lillich, J.; Lloyd, S.L.; Loebinger, F.K.; Lu, J.; Ludwig, J.; Macpherson, A.; Mader, W.; Marcellini, S.; Martin, A.J.; Masetti, G.; Mashimo, T.; Mattig, Peter; McDonald, W.J.; McKenna, J.; McMahon, T.J.; McPherson, R.A.; Meijers, F.; Menges, W.; Merritt, F.S.; Mes, H.; Michelini, A.; Mihara, S.; Mikenberg, G.; Miller, D.J.; Moed, S.; Mohr, W.; Mori, T.; Mutter, A.; Nagai, K.; Nakamura, I.; Nanjo, H.; Neal, H.A.; Nisius, R.; O'Neale, S.W.; Oh, A.; Okpara, A.; Oreglia, M.J.; Orito, S.; Pahl, C.; Pasztor, G.; Pater, J.R.; Patrick, G.N.; Pilcher, J.E.; Pinfold, J.; Plane, David E.; Poli, B.; Polok, J.; Pooth, O.; Przybycien, M.; Quadt, A.; Rabbertz, K.; Rembser, C.; Renkel, P.; Roney, J.M.; Rosati, S.; Rozen, Y.; Runge, K.; Sachs, K.; Saeki, T.; Sarkisyan, E.K.G.; Schaile, A.D.; Schaile, O.; Scharff-Hansen, P.; Schieck, J.; Schoerner-Sadenius, Thomas; Schroder, Matthias; Schumacher, M.; Schwick, C.; Scott, W.G.; Seuster, R.; Shears, T.G.; Shen, B.C.; Sherwood, P.; Siroli, G.; Skuja, A.; Smith, A.M.; Sobie, R.; Soldner-Rembold, S.; Spano, F.; Stahl, A.; Stephens, K.; Strom, David M.; Strohmer, R.; Tarem, S.; Tasevsky, M.; Taylor, R.J.; Teuscher, R.; Thomson, M.A.; Torrence, E.; Toya, D.; Tran, P.; Trigger, I.; Trocsanyi, Z.; Tsur, E.; Turner-Watson, M.F.; Ueda, I.; Ujvari, B.; Vollmer, C.F.; Vannerem, P.; Vertesi, R.; Verzocchi, M.; Voss, H.; Vossebeld, J.; Waller, D.; Ward, C.P.; Ward, D.R.; Watkins, P.M.; Watson, A.T.; Watson, N.K.; Wells, P.S.; Wengler, T.; Wermes, N.; Wetterling, G.W.; Wilson, D.; Wilson, J.A.; Wolf, G.; Wyatt, T.R.; Yamashita, S.; Zer-Zion, D.; Zivkovic, Lidija

    2003-01-01

    A search for single production of doubly-charged Higgs bosons has been performed using 600.7 pb^-1 of e+e- collision data with sqrt(s)=189--209GeV collected by the OPAL detector at LEP. No evidence for the existence of H++/-- is observed. Upper limits on the Yukawa coupling of the H++/-- to like-signed electron pairs are derived. Additionally, indirect constraints on the Yukawa coupling from Bhabha scattering, where the H++/-- would contribute via t-channel exchange, are derived for M(H++/--) < 2TeV. These are the first results for both a single production search and constraints from Bhabha scattering reported from LEP.

  6. Probing single-charge fluctuations at a GaAs/AlAs interface using laser spectroscopy on a nearby InGaAs quantum dot.

    Science.gov (United States)

    Houel, J; Kuhlmann, A V; Greuter, L; Xue, F; Poggio, M; Gerardot, B D; Dalgarno, P A; Badolato, A; Petroff, P M; Ludwig, A; Reuter, D; Wieck, A D; Warburton, R J

    2012-03-09

    We probe local charge fluctuations in a semiconductor via laser spectroscopy on a nearby self-assembled quantum dot. We demonstrate that the quantum dot is sensitive to changes in the local environment at the single-charge level. By controlling the charge state of localized defects, we are able to infer the distance of the defects from the quantum dot with ±5  nm resolution. The results identify and quantify the main source of charge noise in the commonly used optical field-effect devices.

  7. The sonolysis and radiolysis of adenine and related biomolecules

    International Nuclear Information System (INIS)

    Craig, W.K.

    1979-04-01

    The sonolysis of adenine, its nucleoside adenosine and the carbohydrates glucose, fructose and ribose were investigated at 459 Hz. The insonation of air-saturated aqueous adenine solutions degrades adenine at a rate that is linear with time and independent of the initial concentration. The radiolytic decomposition of air-saturated aqueous adenine solutions were also investigated and the degradation products found to be essentially identical to those obtained by sonolysis. since the products derived from sonolysis and radiolysis were similar, a degradation mechanism can be proposed that accounts for all the observed products. The major feature of this mechanism is that the principal loci of attack are the C(8) position and the central C(4)-C(5) double bond. The sonolysis of air-saturated aqueous solutions of the carbohydrates results in the formation of products analogous to those produced by ionizing radiation. While two types of products are formed in the radiolysis of carbohydrate solutions, depending on the initial presence or absence of oxygen, the sonolysis of air-saturated carbohydrate solutions leads to the formation of both types of products. This is due to the depletion of oxygen from the solution during insonation. Existing mechanisms for the radiolytic decomposition of carbohydrates in the presence and absence of oxygen can be modified to rationalize the sonolysis products. Insonation of an aqueous solution of adenosine resulted in the production of adenine and ribose. The other products are consistent with those obtained in the ultrasonic degradation of adenine and ribose

  8. Estimation of the spatial distribution of traps using space-charge-limited current measurements in an organic single crystal

    KAUST Repository

    Dacuña, Javier

    2012-09-06

    We used a mobility edge transport model and solved the drift-diffusion equation to characterize the space-charge-limited current of a rubrene single-crystal hole-only diode. The current-voltage characteristics suggest that current is injection-limited at high voltage when holes are injected from the bottom contact (reverse bias). In contrast, the low-voltage regime shows that the current is higher when holes are injected from the bottom contact as compared to hole injection from the top contact (forward bias), which does not exhibit injection-limited current in the measured voltage range. This behavior is attributed to an asymmetric distribution of trap states in the semiconductor, specifically, a distribution of traps located near the top contact. Accounting for a localized trap distribution near the contact allows us to reproduce the temperature-dependent current-voltage characteristics in forward and reverse bias simultaneously, i.e., with a single set of model parameters. We estimated that the local trap distribution contains 1.19×1011 cm -2 states and decays as exp(-x/32.3nm) away from the semiconductor-contact interface. The local trap distribution near one contact mainly affects injection from the same contact, hence breaking the symmetry in the charge transport. The model also provides information of the band mobility, energy barrier at the contacts, and bulk trap distribution with their corresponding confidence intervals. © 2012 American Physical Society.

  9. Negative Ion MALDI Mass Spectrometry of Polyoxometalates (POMs): Mechanism of Singly Charged Anion Formation and Chemical Properties Evaluation

    Science.gov (United States)

    Boulicault, Jean E.; Alves, Sandra; Cole, Richard B.

    2016-08-01

    MALDI-MS has been developed for the negative ion mode analysis of polyoxometalates (POMs). Matrix optimization was performed using a variety of matrix compounds. A first group of matrixes offers MALDI mass spectra containing abundant intact singly charged anionic adduct ions, as well as abundant in-source fragmentations at elevated laser powers. A relative ranking of the ability to induce POM fragmentation is found to be: DAN > CHCA > CNA > DIT> HABA > DCTB > IAA. Matrixes of a second group provide poorer quality MALDI mass spectra without observable fragments. Sample preparation, including the testing of salt additives, was performed to optimize signals for a model POM, POMc12, the core structure of which bears four negative charges. The matrix 9-cyanoanthracene (CNA) provided the best signals corresponding to singly charged intact POMc12 anions. Decompositions of these intact anionic species were examined in detail, and it was concluded that hydrogen radical-induced mechanisms were not prevalent, but rather that the observed prompt fragments originate from transferred energy derived from initial electronic excitation of the CNA matrix. Moreover, in obtained MALDI mass spectra, clear evidence of electron transfer to analyte POM species was found: a manifestation of the POMs ability to readily capture electrons. The affinity of polyanionic POMc12 toward a variety of cations was evaluated and the following affinity ranking was established: Fe3+ > Al3+ > Li+ > Ga3+ > Co2+ > Cr3+ > Cu2+ > [Mn2+, Mg2+] > [Na+, K+]. Thus, from the available cationic species, specific adducts are preferentially formed, and evidence is given that these higher affinity POM complexes are formed in the gas phase during the early stages of plume expansion.

  10. Giant plasmon excitation in single and double ionization of C60 by fast highly charged Si and O ions

    Science.gov (United States)

    Kelkar, A. H.; Kadhane, U.; Misra, D.; Tribedi, L. C.

    2007-09-01

    Se have investigated single and double ionization of C60 molecule in collisions with 2.33 MeV/u Siq+ (q=6-14) and 3.125 MeV/u Oq+ (q=5-8) projectiles. The projectile charge state dependence of the single and double ionization yields of C60 are then compared to those for an ion-atom collision system using Ne gas as a target. A large difference between the gas and the cluster target behaviour was partially explained in terms of a model based on collective excitation namely the giant dipole plasmon resonance (GDPR). The qualitative agreement between the data and GDPR model prediction for single and double ionization signifies the importance of single and double plasmon excitations in the ionization process. A large deviation of the GDPR model for triple and quadruple ionization from the experimental data imply the importance of the other low impact parameter processes such as evaporation, fragmentation and a possible solid-like dynamical screening.

  11. Giant plasmon excitation in single and double ionization of C60 by fast highly charged Si and O ions

    International Nuclear Information System (INIS)

    Kelkar, A H; Kadhane, U; Misra, D; Tribedi, L C

    2007-01-01

    Se have investigated single and double ionization of C 60 molecule in collisions with 2.33 MeV/u Si q+ (q=6-14) and 3.125 MeV/u O q+ (q=5-8) projectiles. The projectile charge state dependence of the single and double ionization yields of C 60 are then compared to those for an ion-atom collision system using Ne gas as a target. A large difference between the gas and the cluster target behaviour was partially explained in terms of a model based on collective excitation namely the giant dipole plasmon resonance (GDPR). The qualitative agreement between the data and GDPR model prediction for single and double ionization signifies the importance of single and double plasmon excitations in the ionization process. A large deviation of the GDPR model for triple and quadruple ionization from the experimental data imply the importance of the other low impact parameter processes such as evaporation, fragmentation and a possible solid-like dynamical screening

  12. Charge-collection efficiency of single-crystal CVD diamond detector for low-energy charged particles with energies ranging from 100 keV to 2 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Sato, Yuki, E-mail: sato.yuki@jaea.go.jp [Collaborative Laboratories for Advanced Decommissioning Science (CLADS), Japan Atomic Energy Agency, 2–4 Shirane Shirakata, Tokai-mura, Naka-gun, Ibaraki 319-1195 (Japan); Murakami, Hiroyuki [RIKEN Nishina Center for Accelerator-Based Science, RIKEN, 2–1Hirosawa, Wako, Saitama 351-0198 (Japan); Shimaoka, Takehiro; Tsubota, Masakatsu; Kaneko, Junichi H. [Graduate School of Engineering, Hokkaido University, N13, W8, Kita-ku, Sapporo 060-8628 (Japan)

    2016-10-21

    The performance of a diamond detector created from a single-crystal diamond grown by chemical vapor deposition was studied for application in detecting charged particles having energies ranging from 100 keV to 2 MeV. Energy peaks of different low-energy ions were clearly observed. However, we observed that the pulse height for individual incident ions decreases with increasing atomic number of the ions. We estimated the charge collection efficiency of the generated charge carriers by the incident charged particles. The charge collection efficiencies are 97.0 ± 0.7% for 2 MeV helium-ions (He{sup +}). On the other hand, compared with that of He{sup +}, silicon-ions (Si{sup +}) and gold-ions (Au{sup 3+}) show low charge collection efficiency: 70.6 ± 2.2% and 29.5 ± 4.2% for 2 MeV-Si{sup +} and 2 MeV-Au{sup 3+}, respectively. We also found that the charge collection efficiency decreases as the generated charge density inside the diamond crystal increases.

  13. Long-range charge transport in single G-quadruplex DNA molecules

    DEFF Research Database (Denmark)

    Livshits, Gideon I.; Stern, Avigail; Rotem, Dvir

    2014-01-01

    DNA and DNA-based polymers are of interest in molecular electronics because of their versatile and programmable structures. However, transport measurements have produced a range of seemingly contradictory results due to differences in the measured molecules and experimental set-ups, and transport......DNA and DNA-based polymers are of interest in molecular electronics because of their versatile and programmable structures. However, transport measurements have produced a range of seemingly contradictory results due to differences in the measured molecules and experimental set......-ups, and transporting significant current through individual DNA-based molecules remains a considerable challenge. Here, we report reproducible charge transport in guanine-quadruplex (G4) DNA molecules adsorbed on a mica substrate. Currents ranging from tens of picoamperes to more than 100 pA were measured in the G4......-DNA over distances ranging from tens of nanometres to more than 100 nm. Our experimental results, combined with theoretical modelling, suggest that transport occurs via a thermally activated long-range hopping between multi-tetrad segments of DNA. These results could re-ignite interest in DNA...

  14. Kidney Disease in Adenine Phosphoribosyltransferase Deficiency.

    Science.gov (United States)

    Runolfsdottir, Hrafnhildur Linnet; Palsson, Runolfur; Agustsdottir, Inger M; Indridason, Olafur S; Edvardsson, Vidar O

    2016-03-01

    Adenine phosphoribosyltransferase (APRT) deficiency is a purine metabolism disorder causing kidney stones and chronic kidney disease (CKD). The course of nephrolithiasis and CKD has not been well characterized. The objective of this study was to examine long-term kidney outcomes in patients with APRT deficiency. An observational cohort study. All patients enrolled in the APRT Deficiency Registry of the Rare Kidney Stone Consortium. Kidney stones, acute kidney injury (AKI), stage of CKD, end-stage renal disease, estimated glomerular filtration rate (eGFR), and changes in eGFR. Serum creatinine and eGFR calculated using creatinine-based equations. Of 53 patients, 30 (57%) were females and median age at diagnosis was 37.0 (range, 0.6-67.9) years. Median duration of follow-up was 10.3 (range, 0.0-31.5) years. At diagnosis, kidney stones had developed in 29 (55%) patients and 20 (38%) had CKD stages 3 to 5, including 11 (21%) patients with stage 5. At latest follow-up, 33 (62%) patients had experienced kidney stones; 18 (34%), AKI; and 22 (42%), CKD stages 3 to 5. Of 14 (26%) patients with stage 5 CKD, 12 had initiated renal replacement therapy. Kidney stones recurred in 18 of 33 (55%) patients. The median eGFR slope was -0.38 (range, -21.99 to 1.42) mL/min/1.73m(2) per year in patients receiving treatment with an xanthine dehydrogenase inhibitor and -5.74 (range, -75.8 to -0.10) mL/min/1.73m(2) per year in those not treated prior to the development of stage 5 CKD (P=0.001). Use of observational registry data. Progressive CKD and AKI episodes are major features of APRT deficiency, whereas nephrolithiasis is the most common presentation. Advanced CKD without a history of kidney stones is more prevalent than previously reported. Our data suggest that timely therapy may retard CKD progression. Copyright © 2016 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.

  15. A fast, low power and low noise charge sensitive amplifier ASIC for a UV imaging single photon detector

    Science.gov (United States)

    Seljak, A.; Cumming, H. S.; Varner, G.; Vallerga, J.; Raffanti, R.; Virta, V.

    2017-04-01

    NASA has funded, through their Strategic Astrophysics Technology (SAT) program, the development of a cross strip (XS) microchannel plate (MCP) detector with the intention to increase its technology readiness level (TRL), enabling prototyping for future NASA missions. One aspect of the development is to convert the large and high powered laboratory Parallel Cross Strip (PXS) readout electronics into application specific integrated circuits (ASICs) to decrease their mass, volume, and power consumption (all limited resources in space) and to make them more robust to the environments of rocket launch and space. The redesign also foresees to increase the overall readout event rate, and decrease the noise contribution of the readout system. This work presents the design and verification of the first stage for the new readout system, the 16 channel charge sensitive amplifier ASIC, called the CSAv3. The single channel amplifier is composed of a charge sensitive amplifier (pre-amplifier), a pole zero cancellation circuit and a shaping amplifier. An additional output stage buffer allows polarity selection of the output analog signal. The operation of the amplifier is programmable via serial bus. It provides an equivalent noise charge (ENC) of around 600 e^- and a baseline gain of 10 mV/fC. The full scale pulse shaped output signal is confined within 100 ns, without long recovery tails, enabling up to 10 MHz periodic event rates without signal pile up. This ASIC was designed and fabricated in 130 nm, TSMC CMOS 1.2 V technology. In addition, we briefly discuss the construction of the readout system and plans for the future work.

  16. Charge transferred doping of single layer graphene by mono-dispersed manganese-oxide nanoparticles adsorption

    Science.gov (United States)

    Phan, Thanh Luan; Kang, Myunggoo; Choi, Soo Ho; Kim, You Joong; Jung, Hyun; Yoon, Im Taek; Yang, Woochul

    2017-10-01

    We report an efficient and controllable method to introduce p-type doping in graphene by decoration with Mn3O4 nanoparticles (NPs) on mechanically exfoliated single layer graphene. A monolayer of Mn3O4 NPs, with a diameter in the range of 5-10 nm, was decorated on a graphene film using an ex-situ method, whereas by controlling the coverage of the NPs on the graphene surface, the carrier concentration could be continually adjusted. The p-type of the NP-decorated single layer graphene was confirmed by the Raman G-band. It was found that the carrier concentration could be gradually adjusted up to 26.09 × 1012 cm-2, with 90% coverage of Mn3O4 NPs. The Dirac point of the pristine graphene at the gate bias of 27 V shifted to 150 V for Mn3O4 NP decorated graphene. The p-type graphene doped with Mn3O4 NPs demonstrated significant high air-stability, even under an oxygen atmosphere for 60 days. This approach allows for the opportunity for simple, scalable, and highly stable doping of graphene for future high-performance electronic device applications.

  17. Non-Covalent Interactions and Impact of Charge Penetration Effects in Linear Oligoacene Dimers and Single Crystals

    KAUST Repository

    Ryno, Sean

    2016-05-18

    Non-covalent interactions determine in large part the thermodynamic aspects of molecular packing in organic crystals. Using a combination of symmetry-adapted perturbation theory (SAPT) and classical multipole electrostatics, we describe the interaction potential energy surfaces for dimers of the oligoacene family, from benzene to hexacene. An analysis of these surfaces and a thorough assessment of dimers extracted from the reported crystal structures underline that high-order interactions (i.e., three-body non-additive interactions) must be considered in order to rationalize the details of the crystal structures. A comparison of the SAPT electrostatic energy with the multipole interaction energy demonstrates the importance of the contribution of charge penetration, which is shown to account for up to 50% of the total interaction energy in dimers extracted from the experimental single crystals; in the case of the most stable co-facial model dimers, this contribution is even larger than the total interaction energy. Our results highlight the importance of taking account of charge penetration in studies of the larger oligoacenes.

  18. Theoretical study on absorption and emission spectra of adenine analogues.

    Science.gov (United States)

    Liu, Hongxia; Song, Qixia; Yang, Yan; Li, Yan; Wang, Haijun

    2014-04-01

    Fluorescent nucleoside analogues have attracted much attention in studying the structure and dynamics of nucleic acids in recent years. In the present work, we use theoretical calculations to investigate the structural and optical properties of four adenine analogues (termed as A1, A2, A3, and A4), and also consider the effects of aqueous solution and base pairing. The results show that the fluorescent adenine analogues can pair with thymine to form stable H-bonded WC base pairs. The excited geometries of both adenine analogues and WC base pairs are similar to the ground geometries. The absorption and emission maxima of adenine analogues are greatly red shifted compared with nature adenine, the oscillator strengths of A1 and A2 are stronger than A3 and A4 in both absorption and emission spectra. The calculated low-energy peaks in the absorption spectra are in good agreement with the experimental data. In general, the aqueous solution and base pairing can slightly red-shift both the absorption and emission maxima, and can increase the oscillator strengths of absorption spectra, but significantly decrease the oscillator strengths of A3 in emission spectra.

  19. Longitudinal transport coefficients of a magnetized plasma consisting of hydrogen and a single impurity element in arbitrarily populated charge states

    International Nuclear Information System (INIS)

    Claassen, H.A.; Gerhauser, H.; El-Sharif, R.N.

    1991-01-01

    The coefficients determining the transport processes along the magnetic field in a magnetized plasma consisting of electrons, protons/deuterons and impurity ions in various charge states have been calculated on the basis of Grad's 21 moment approximation. Assuming a single impurity element, the determinants appearing in the transport coefficients are evaluated analytically for arbitrary ratios m z /m + between the impurity and hydrogen masses. The general formulae are then simplified for the important case m z /m + ≥ 1 and compared with existing data given by V.M. Zhdanov et al. and Yu.L. Igitkhanov et al. Whereas with minor modifications the proton/deuteron and electron coefficients agree well, there are remarkable differences in the impurity ion transport coefficients, which are discussed. (orig.)

  20. Probing single- to multi-cell level charge transport in Geobacter sulfurreducens DL-1.

    Science.gov (United States)

    Jiang, Xiaocheng; Hu, Jinsong; Petersen, Emily R; Fitzgerald, Lisa A; Jackan, Charles S; Lieber, Alexander M; Ringeisen, Bradley R; Lieber, Charles M; Biffinger, Justin C

    2013-01-01

    Microbial fuel cells, in which living microorganisms convert chemical energy into electricity, represent a potentially sustainable energy technology for the future. Here we report the single-bacterium level current measurements of Geobacter sulfurreducens DL-1 to elucidate the fundamental limits and factors determining maximum power output from a microbial fuel cell. Quantized stepwise current outputs of 92(±33) and 196(±20) fA are generated from microelectrode arrays confined in isolated wells. Simultaneous cell imaging/tracking and current recording reveals that the current steps are directly correlated with the contact of one or two cells with the electrodes. This work establishes the amount of current generated by an individual Geobacter cell in the absence of a biofilm and highlights the potential upper limit of microbial fuel cell performance for Geobacter in thin biofilms.

  1. Time-dependent density-functional-theory investigation of the collisions of protons and α particles with uracil and adenine

    Science.gov (United States)

    Covington, Cody; Hartig, Kara; Russakoff, Arthur; Kulpins, Ryan; Varga, Kálmán

    2017-05-01

    Time-dependent density-functional theory was employed to study the effects of proton and α -particle radiation on uracil and adenine. This method has the advantage of treating nuclear motion and electronic motion simultaneously, allowing for the study of electronic excitation, charge transfer, ionization, and nuclear motion. Particle energies were surveyed in the range of 15-500 keV for protons and 100-2000 keV for α particles in conjunction with impact points both on and off carbon bonds in order to investigate the electron and nuclear dynamics of irradiated molecules and the form and quantity of transferred energy. The stopping power, energy transferred, and ionization were found, and the relationship between incident particle energy and electron density of the target molecule was characterized for proton and α -particle radiation incident on adenine and uracil.

  2. NMR studies on an oligodeoxynucleotide containing 2-aminopurine opposite adenine

    International Nuclear Information System (INIS)

    Fazakerley, G.V.; Sowers, L.C.; Eritja, R.; Kaplan, B.E.; Goodman, M.F.

    1987-01-01

    A heteroduplex containing the mismatch 2-aminopurine (AP)-adenine has been synthesized and studied by proton NMR. The mismatch was incorporated into the sequence d[CGG(AP)GGC] x d-(GCCACCG). One-dimensional nuclear Overhauser effect measurements in H 2 O and two-dimensional nuclear Overhauser effect spectra in D 2 O show AP x A base pairs in a wobble structure in which both bases are in the anti conformation. The adenine is stacked well in the helix, but the helix twist between the adenine and neighboring cytosine in the 3' direction is unusually small. As a result, the aminopurine on the opposite strand is somewhat pushed out of the helix. From the measurements of the imino proton line widths, the two adjacent G x C base pairs are not found to be significantly destabilized by the presence of the purine-purine wobble pair

  3. The Charging Process in a High-speed, Single-cylinder, Four-stroke Engine

    Science.gov (United States)

    Reynolds, Blake; Schecter, Harry; Taylor, E S

    1939-01-01

    Experimental measurements and theoretical calculations were made on an aircraft-type, single cylinder engine, in order to determine the physical nature of the inlet process, especially at high piston speeds. The engine was run at speeds from 1,500 to 2,600 r.p.m. (mean piston speeds of 1,370 to 2,380 feet per minute). Measurements were made of the cylinder pressure during the inlet stroke and of the power output and volumetric efficiency. Measurements were also made, with the engine not running, to determine the resistance and mass of air in the inlet valve port at various crank angles. Results of analysis indicate that mass has an appreciable effect, but friction plays the major part in restricting flow. The observed fact that the volumetric efficiency is considerably less than 100 percent is attributed to thermal effects. An estimate was made of the magnitude of these effects in the present case, and their general nature is discussed.

  4. Study of CP-violating charge asymmetries of single muons and like-sign dimuons in p pbar collisions

    Czech Academy of Sciences Publication Activity Database

    Abazov, V. M.; Abbott, B.; Acharya, B.S.; Kupčo, Alexander; Lokajíček, Miloš

    2014-01-01

    Roč. 89, č. 1 (2014), "012002-1"-"012002-31" ISSN 1550-7998 R&D Projects: GA MŠk(CZ) LG12006 Institutional support: RVO:68378271 Keywords : D0 * Fermilab * charge asymmetry * CP violation * same sign * charge: asymmetry * dimuon * charge * muon * charge * meson * mixing * width difference Subject RIV: BF - Elementary Particles and High Energy Physics Impact factor: 4.643, year: 2014

  5. Exclusion of exotic top-like quarks with -4/3 electric charge using jet-charge tagging in single-lepton ttbar events at CDF

    CERN Document Server

    Aaltonen, T.; Amidei, D.; Anastassov, A.; Annovi, A.; Antos, J.; Apollinari, G.; Appel, J.A.; Arisawa, T.; Artikov, A.; Asaadi, J.; Ashmanskas, W.; Auerbach, B.; Aurisano, A.; Azfar, F.; Badgett, W.; Bae, T.; Barbaro-Galtieri, A.; Barnes, V.E.; Barnett, B.A.; Barria, P.; Bartos, P.; Bauce, M.; Bedeschi, F.; Behari, S.; Bellettini, G.; Bellinger, J.; Benjamin, D.; Beretvas, A.; Bhatti, A.; Bland, K.R.; Blumenfeld, B.; Bocci, A.; Bodek, A.; Boisvert, V.; Bortoletto, D.; Boudreau, J.; Boveia, A.; Brigliadori, L.; Bromberg, C.; Brucken, E.; Budagov, J.; Budd, H.S.; Burkett, K.; Busetto, G.; Bussey, P.; Butti, P.; Buzatu, A.; Calamba, A.; Camarda, S.; Campanelli, M.; Canelli, F.; Carls, B.; Carlsmith, D.; Carosi, R.; Carrillo, S.; Casal, B.; Casarsa, M.; Castro, A.; Catastini, P.; Cauz, D.; Cavaliere, V.; Cavalli-Sforza, M.; Cerri, A.; Cerrito, L.; Chen, Y.C.; Chertok, M.; Chiarelli, G.; Chlachidze, G.; Cho, K.; Chokheli, D.; Ciocci, M.A.; Clark, A.; Clarke, C.; Convery, M.E.; Conway, J.; Corbo, M.; Cordelli, M.; Cox, C.A.; Cox, D.J.; Cremonesi, M.; Cruz, D.; Cuevas, J.; Culbertson, R.; d'Ascenzo, N.; Datta, M.; de Barbaro, P.; Demortier, L.; Deninno, M.; d'Errico, M.; Devoto, F.; Di Canto, A.; Di Ruzza, B.; Dittmann, J.R.; D'Onofrio, M.; Donati, S.; Dorigo, M.; Driutti, A.; Ebina, K.; Edgar, R.; Elagin, A.; Erbacher, R.; Errede, S.; Esham, B.; Eusebi, R.; Farrington, S.; Fernandez Ramos, J.P.; Field, R.; Flanagan, G.; Forrest, R.; Franklin, M.; Freeman, J.C.; Frisch, H.; Funakoshi, Y.; Garfinkel, A.F.; Garosi, P.; Gerberich, H.; Gerchtein, E.; Giagu, S.; Giakoumopoulou, V.; Gibson, K.; Ginsburg, C.M.; Giokaris, N.; Giromini, P.; Giurgiu, G.; Glagolev, V.; Glenzinski, D.; Gold, M.; Goldin, D.; Golossanov, A.; Gomez, G.; Gomez-Ceballos, G.; Goncharov, M.; Gonzalez Lopez, O.; Gorelov, I.; Goshaw, A.T.; Goulianos, K.; Gramellini, E.; Grinstein, S.; Grosso-Pilcher, C.; Group, R.C.; Guimaraes da Costa, J.; Hahn, S.R.; Han, J.Y.; Happacher, F.; Hara, K.; Hare, M.; Harr, R.F.; Harrington-Taber, T.; Hatakeyama, K.; Hays, C.; Heinrich, J.; Herndon, M.; Hocker, A.; Hong, Z.; Hopkins, W.; Hou, S.; Hughes, R.E.; Husemann, U.; Hussein, M.; Huston, J.; Introzzi, G.; Iori, M.; Ivanov, A.; James, E.; Jang, D.; Jayatilaka, B.; Jeon, E.J.; Jindariani, S.; Jones, M.; Joo, K.K.; Jun, S.Y.; Junk, T.R.; Kambeitz, M.; Kamon, T.; Karchin, P.E.; Kasmi, A.; Kato, Y.; Ketchum, W.; Keung, J.; Kilminster, B.; Kim, D.H.; Kim, H.S.; Kim, J.E.; Kim, M.J.; Kim, S.B.; Kim, S.H.; Kim, Y.J.; Kim, Y.K.; Kimura, N.; Kirby, M.; Knoepfel, K.; Kondo, K.; Kong, D.J.; Konigsberg, J.; Kotwal, A.V.; Kreps, M.; Kroll, J.; Kruse, M.; Kuhr, T.; Kurata, M.; Laasanen, A.T.; Lammel, S.; Lancaster, M.; Lannon, K.; Latino, G.; Lee, H.S.; Lee, J.S.; Leo, S.; Leone, S.; Lewis, J.D.; Limosani, A.; Lipeles, E.; Lister, A.; Liu, H.; Liu, Q.; Liu, T.; Lockwitz, S.; Loginov, A.; Luca, A.; Lucchesi, D.; Lueck, J.; Lujan, P.; Lukens, P.; Lungu, G.; Lys, J.; Lysak, R.; Madrak, R.; Maestro, P.; Malik, S.; Manca, G.; Manousakis-Katsikakis, A.; Margaroli, F.; Marino, P.; Martinez, M.; Matera, K.; Mattson, M.E.; Mazzacane, A.; Mazzanti, P.; McFarland, K.S.; McNulty, R.; Mehta, A.; Mehtala, P.; Mesropian, C.; Miao, T.; Mietlicki, D.; Mitra, A.; Miyake, H.; Moed, S.; Moggi, N.; Moon, C.S.; Moore, R.; Morello, M.J.; Mukherjee, A.; Muller, Th.; Murat, P.; Mussini, M.; Nachtman, J.; Nagai, Y.; Naganoma, J.; Nakano, I.; Napier, A.; Nett, J.; Neu, C.; Nigmanov, T.; Nodulman, L.; Noh, S.Y.; Norniella, O.; Oakes, L.; Oh, S.H.; Oh, Y.D.; Oksuzian, I.; Okusawa, T.; Orava, R.; Ortolan, L.; Pagliarone, C.; Palencia, E.; Palni, P.; Papadimitriou, V.; Parker, W.; Pauletta, G.; Paulini, M.; Paus, C.; Phillips, T.J.; Piacentino, G.; Pianori, E.; Pilot, J.; Pitts, K.; Plager, C.; Pondrom, L.; Poprocki, S.; Potamianos, K.; Pranko, A.; Prokoshin, F.; Ptohos, F.; Punzi, G.; Ranjan, N.; Redondo Fernandez, I.; Renton, P.; Rescigno, M.; Rimondi, F.; Ristori, L.; Robson, A.; Rodriguez, T.; Rolli, S.; Ronzani, M.; Roser, R.; Rosner, J.L.; Ruffini, F.; Ruiz, A.; Russ, J.; Rusu, V.; Sakumoto, W.K.; Sakurai, Y.; Santi, L.; Sato, K.; Saveliev, V.; Savoy-Navarro, A.; Schlabach, P.; Schmidt, E.E.; Schwarz, T.; Scodellaro, L.; Scuri, F.; Seidel, S.; Seiya, Y.; Semenov, A.; Sforza, F.; Shalhout, S.Z.; Shears, T.; Shepard, P.F.; Shimojima, M.; Shochet, M.; Shreyber-Tecker, I.; Simonenko, A.; Sinervo, P.; Sliwa, K.; Smith, J.R.; Snider, F.D.; Song, H.; Sorin, V.; Stancari, M.; St. Denis, R.; Stelzer, B.; Stelzer-Chilton, O.; Stentz, D.; Strologas, J.; Sudo, Y.; Sukhanov, A.; Suslov, I.; Takemasa, K.; Takeuchi, Y.; Tang, J.; Tecchio, M.; Teng, P.K.; Thom, J.; Thomson, E.; Thukral, V.; Toback, D.; Tokar, S.; Tollefson, K.; Tomura, T.; Tonelli, D.; Torre, S.; Torretta, D.; Totaro, P.; Trovato, M.; Ukegawa, F.; Uozumi, S.; Vazquez, F.; Velev, G.; Vellidis, C.; Vernieri, C.; Vidal, M.; Vilar, R.; Vizan, J.; Vogel, M.; Volpi, G.; Wagner, P.; Wallny, R.; Wang, S.M.; Warburton, A.; Waters, D.; Wester, W.C., III; Whiteson, D.; Wicklund, A.B.; Wilbur, S.; Williams, H.H.; Wilson, J.S.; Wilson, P.; Winer, B.L.; Wittich, P.; Wolbers, S.; Wolfe, H.; Wright, T.; Wu, X.; Wu, Z.; Yamamoto, K.; Yamato, D.; Yang, T.; Yang, U.K.; Yang, Y.C.; Yao, W.M.; Yeh, G.P.; Yi, K.; Yoh, J.; Yorita, K.; Yoshida, T.; Yu, G.B.; Yu, I.; Zanetti, A.M.; Zeng, Y.; Zhou, C.; Zucchelli, S.

    2013-08-05

    We report on a measurement of the top-quark electric charge in ttbar events in which one W boson originating from the top-quark pair decays into leptons and the other into hadrons. The event sample was collected by the CDF II detector in sqrt(s)=1.96 TeV proton-antiproton collisions and corresponds to 5.6 fb^(-1). We find the data to be consistent with the standard model and exclude the existence of an exotic quark with -4/3 electric charge and mass of the conventional top quark at the 99% confidence level.

  6. Study of the Bulk Charge Carrier Dynamics in Anatase and Rutile TiO2 Single Crystals by Femtosecond Time Resolved Spectroscopy

    KAUST Repository

    Maity, Partha

    2018-04-02

    Understanding of the fundamentals behind charge carriers of photo-catalytic materials are still illusive hindering progress in our quest for renewable energy. TiO2 anatase and rutile are the most understood phases in photo-catalysis and serve as the best model for fundamental studies. Their ultrafast charge carrier dynamics especially on TiO2 anatase single crystal (the most active phase) are unresolved. Here femtosecond time resolved spectroscopy (TRS) was carried out to explore the dynamics of photo-excited charge carriers’ recombination in anatase single crystal, for the first time using pump fluence effects, and compares it to that of the rutile single crystal. A significant difference in charge carrier recombination rates between both crystals is observed. We found that the time constants for carrier recombination are two orders of magnitude slower for anatase (101) when compared to those of rutile (110). Moreover, bulk defects introduced by reduction of the samples via annealing in ultra-high vacuum resulted in faster recombination rates for both polymorphs. Both states (fresh and reduced) probed by pump fluence dependence measurements revealed that the major recombination channel in fresh and reduced anatase and reduced rutile is the first-order Shockley–Reed mediated. However, for fresh rutile, third-body Auger recombination was observed, attributed to the presence of higher density of intrinsic charge carriers. At all excitation wavelengths and fluence investigated, anatase (101) single crystal show longer charge carrier lifetime when compared to rutile (110) single. This may explain the superiority of the anatase phase for the electron transfer H+ reduction to molecular hydrogen.

  7. Effect of Adenine Concentration on the Corrosion Inhibition of Aisi ...

    African Journals Online (AJOL)

    This gave a surface coverage of 0.8956 and corrosion penetration rate of 0.022132mm/yr. Hence, the best adenine concentration for the corrosion inhibition of alloys 304L in 1.0M sulphuric acid solution to obtain optimum inhibition efficiency is 0.011M. Keywords: Corrosion, AISI 304L Steel, Inhibition efficiency, Degree of ...

  8. Protection of Chinese herbs against Adenine-induced chronic renal ...

    African Journals Online (AJOL)

    The aim of the study is to evaluate the efficacy of Chinese herbs (Angelica sinensis, Ligusticum wallichii, Salvia miltiorrhiza, Rhizoma dioscoreae, Rhodiola crenilata, Astragalus membranaceus and Angelica sinensis) on adenine-induced chronic renal failure in rats. 30 age-matched male Wistar rats were divided into three ...

  9. Selective inhibition of nicotinamide adenine dinucleotide kinases by dinucleoside disulfide mimics of nicotinamide adenine dinucleotide analogues.

    Science.gov (United States)

    Petrelli, Riccardo; Sham, Yuk Yin; Chen, Liqiang; Felczak, Krzysztof; Bennett, Eric; Wilson, Daniel; Aldrich, Courtney; Yu, Jose S; Cappellacci, Loredana; Franchetti, Palmarisa; Grifantini, Mario; Mazzola, Francesca; Di Stefano, Michele; Magni, Giulio; Pankiewicz, Krzysztof W

    2009-08-01

    Diadenosine disulfide (5) was reported to inhibit NAD kinase from Listeria monocytogenes and the crystal structure of the enzyme-inhibitor complex has been solved. We have synthesized tiazofurin adenosine disulfide (4) and the disulfide 5, and found that these compounds were moderate inhibitors of human NAD kinase (IC(50)=110 microM and IC(50)=87 microM, respectively) and Mycobacterium tuberculosis NAD kinase (IC(50)=80 microM and IC(50)=45 microM, respectively). We also found that NAD mimics with a short disulfide (-S-S-) moiety were able to bind in the folded (compact) conformation but not in the common extended conformation, which requires the presence of a longer pyrophosphate (-O-P-O-P-O-) linkage. Since majority of NAD-dependent enzymes bind NAD in the extended conformation, selective inhibition of NAD kinases by disulfide analogues has been observed. Introduction of bromine at the C8 of the adenine ring restricted the adenosine moiety of diadenosine disulfides to the syn conformation making it even more compact. The 8-bromoadenosine adenosine disulfide (14) and its di(8-bromoadenosine) analogue (15) were found to be the most potent inhibitors of human (IC(50)=6 microM) and mycobacterium NAD kinase (IC(50)=14-19 microM reported so far. None of the disulfide analogues showed inhibition of lactate-, and inosine monophosphate-dehydrogenase (IMPDH), enzymes that bind NAD in the extended conformation.

  10. Effect of multiple plasmon excitation on single, double and multiple ionizations of C60 in collisions with fast highly charged Si ions

    International Nuclear Information System (INIS)

    Kelkar, A H; Kadhane, U; Misra, D; Kumar, A; Tribedi, L C

    2007-01-01

    We have investigated the single and multiple ionizations of the C 60 molecule in collisions with fast Si q+ projectiles for various projectile charge states (q) between q = 6 and 14. The q-dependence of the ionization cross sections and their ratios is compared with the giant dipole plasmon resonance (GDPR) model. The excellent qualitative agreement with the model in case of single and double ionizations and also a reasonable agreement with the triple (and to some extent with quadruple) ionization (without evaporation) yields signify dominant contributions of the single-, double- and triple-plasmon excitations on the single- and multiple-ionization process

  11. Effect of multiple plasmon excitation on single, double and multiple ionizations of C60 in collisions with fast highly charged Si ions

    Science.gov (United States)

    Kelkar, A. H.; Kadhane, U.; Misra, D.; Kumar, A.; Tribedi, L. C.

    2007-06-01

    We have investigated the single and multiple ionizations of the C60 molecule in collisions with fast Siq+ projectiles for various projectile charge states (q) between q = 6 and 14. The q-dependence of the ionization cross sections and their ratios is compared with the giant dipole plasmon resonance (GDPR) model. The excellent qualitative agreement with the model in case of single and double ionizations and also a reasonable agreement with the triple (and to some extent with quadruple) ionization (without evaporation) yields signify dominant contributions of the single-, double- and triple-plasmon excitations on the single- and multiple-ionization process.

  12. Effect of multiple plasmon excitation on single, double and multiple ionizations of C{sub 60} in collisions with fast highly charged Si ions

    Energy Technology Data Exchange (ETDEWEB)

    Kelkar, A H; Kadhane, U; Misra, D; Kumar, A; Tribedi, L C [Tata Institute of Fundamental Research, Colaba, Mumbai -5 (India)

    2007-06-28

    We have investigated the single and multiple ionizations of the C{sub 60} molecule in collisions with fast Si{sup q+} projectiles for various projectile charge states (q) between q = 6 and 14. The q-dependence of the ionization cross sections and their ratios is compared with the giant dipole plasmon resonance (GDPR) model. The excellent qualitative agreement with the model in case of single and double ionizations and also a reasonable agreement with the triple (and to some extent with quadruple) ionization (without evaporation) yields signify dominant contributions of the single-, double- and triple-plasmon excitations on the single- and multiple-ionization process.

  13. Catalytic Mechanism and Three-Dimensional Structure of Adenine Deaminase

    Energy Technology Data Exchange (ETDEWEB)

    Kamat, S.S.; Swaminathan, S.; Bagaria, A.; Kumaran, D.; Holmes-Hampton, G. P.; Fan, H.; Sali, A.; Sauder, J. M.; Burley, S. K.; Lindahl, P. A.; Raushel, F. M.

    2011-03-22

    Adenine deaminase (ADE) catalyzes the conversion of adenine to hypoxanthine and ammonia. The enzyme isolated from Escherichia coli using standard expression conditions was low for the deamination of adenine (k{sub cat} = 2.0 s{sup -1}; k{sub cat}/K{sub m} = 2.5 x 10{sup 3} M{sup -1} s{sup -1}). However, when iron was sequestered with a metal chelator and the growth medium was supplemented with Mn{sup 2+} prior to induction, the purified enzyme was substantially more active for the deamination of adenine with kcat and kcat/Km values of 200 s{sup -1} and 5 x 10{sup 5} M{sup -1} s{sup -1}, respectively. The apoenzyme was prepared and reconstituted with Fe{sup 2+}, Zn{sup 2+}, or Mn{sup 2+}. In each case, two enzyme equivalents of metal were necessary for reconstitution of the deaminase activity. This work provides the first example of any member of the deaminase subfamily of the amidohydrolase superfamily to utilize a binuclear metal center for the catalysis of a deamination reaction. [Fe{sup II}/Fe{sup II}]-ADE was oxidized to [Fe{sup III}/Fe{sup III}]-ADE with ferricyanide with inactivation of the deaminase activity. Reducing [Fe{sup III}/Fe{sup III}]-ADE with dithionite restored the deaminase activity, and thus, the diferrous form of the enzyme is essential for catalytic activity. No evidence of spin coupling between metal ions was evident by electron paramagnetic resonance or Moessbauer spectroscopy. The three-dimensional structure of adenine deaminase from Agrobacterium tumefaciens (Atu4426) was determined by X-ray crystallography at 2.2 {angstrom} resolution, and adenine was modeled into the active site on the basis of homology to other members of the amidohydrolase superfamily. On the basis of the model of the adenine-ADE complex and subsequent mutagenesis experiments, the roles for each of the highly conserved residues were proposed. Solvent isotope effects, pH-rate profiles, and solvent viscosity were utilized to propose a chemical reaction mechanism and the

  14. Catalytic Mechanism and Three-Dimensional Structure of Adenine Deaminase

    Energy Technology Data Exchange (ETDEWEB)

    S Kamat; A Bagaria; D Kumaran; G Holmes-Hampton; H Fan; A Sali; J Sauder; S Burley; P Lindahl; et. al.

    2011-12-31

    Adenine deaminase (ADE) catalyzes the conversion of adenine to hypoxanthine and ammonia. The enzyme isolated from Escherichia coli using standard expression conditions was low for the deamination of adenine (k{sub cat} = 2.0 s{sup -1}; k{sub cat}/K{sub m} = 2.5 x 10{sup 3} M{sup -1} s{sup -1}). However, when iron was sequestered with a metal chelator and the growth medium was supplemented with Mn{sup 2+} prior to induction, the purified enzyme was substantially more active for the deamination of adenine with k{sub cat} and k{sub cat}/K{sub m} values of 200 s{sup -1} and 5 x 10{sup 5} M{sup -1} s{sup -1}, respectively. The apoenzyme was prepared and reconstituted with Fe{sup 2+}, Zn{sup 2+}, or Mn{sup 2+}. In each case, two enzyme equivalents of metal were necessary for reconstitution of the deaminase activity. This work provides the first example of any member of the deaminase subfamily of the amidohydrolase superfamily to utilize a binuclear metal center for the catalysis of a deamination reaction. [Fe{sup II}/Fe{sup II}]-ADE was oxidized to [Fe{sup III}/Fe{sup III}]-ADE with ferricyanide with inactivation of the deaminase activity. Reducing [Fe{sup III}/Fe{sup III}]-ADE with dithionite restored the deaminase activity, and thus, the diferrous form of the enzyme is essential for catalytic activity. No evidence of spin coupling between metal ions was evident by electron paramagnetic resonance or Moessbauer spectroscopy. The three-dimensional structure of adenine deaminase from Agrobacterium tumefaciens (Atu4426) was determined by X-ray crystallography at 2.2 {angstrom} resolution, and adenine was modeled into the active site on the basis of homology to other members of the amidohydrolase superfamily. On the basis of the model of the adenine-ADE complex and subsequent mutagenesis experiments, the roles for each of the highly conserved residues were proposed. Solvent isotope effects, pH-rate profiles, and solvent viscosity were utilized to propose a chemical reaction

  15. Surface-Enhanced Raman Scattering of the Complexes of Silver with Adenine and dAMP

    OpenAIRE

    Otto, Cornelis; Hoeben, F.P.; Hoeben, F.P.; Greve, Jan

    1991-01-01

    The behaviour of adenine and 2'-deoxyadenosine-5'-monophosphate (dAMP) at positive surface potentials of a silver working electrode was investigated using surface-enhanced Raman scattering (SERS). The use of positive potentials in the presence of adenine or dAMP leads to a rapid accumulation of an intense spectrum. It is proposed that complexes of adenine (dAMP) with silver generate the observed spectra. Adenine and dAMP can be distinguished spectroscopically due to various different complexe...

  16. Measurement and Calculation of Absolute Single- and Multiple-Charge-Exchange Cross Sections for Feq+ Ions Impacting CO and CO2

    Energy Technology Data Exchange (ETDEWEB)

    Simcic, J. [Jet Propulsion Laboratory/Caltech; Schultz, David Robert [ORNL; Mawhorter, R. J. [Pomona College; Cadez, I. [Jozef Stefan Institute, Slovenia; Greenwood, J. B. [Queen' s University, Belfast; Chutjian, A. [Jet Propulsion Laboratory/Caltech; Lisse, Carey M. [Johns Hopkins University; Smith, S. J. [Indiana Wesleyan University, Marion

    2010-01-01

    Absolute cross sections are reported for single, double, and triple charge exchange of Feq+ (q=5- 13) ions with CO and CO2. The highly-charged Fe ions are generated in an electron cyclotron resonance ion source. Absolute data are derived from knowledge of the target gas pressure, target path length, and incident and charge-exchanged ion currents. Experimental results are compared with new calculations of these cross sections in the n-electron classical trajectory Monte-Carlo approximation, in which the ensuing radiative and non-radiative cascades are approximated with scaled hydrogenic transition probabilities and scaled Auger rates. The present data are needed in astrophysical applications of solar- and stellar-wind charge-exchange with comets, planetary atmospheres, and circumstellar clouds.

  17. Single and multiple ionization of C60 fullerenes and collective effects in collisions with highly charged C, F, and Si ions with energy 3 MeV/u

    Science.gov (United States)

    Kelkar, A. H.; Kadhane, U.; Misra, D.; Gulyas, L.; Tribedi, L. C.

    2010-10-01

    We have measured absolute cross sections for single, double, triple, and quadruple ionization of C60 in collisions with 3 MeV/u C, F, and Si projectile ions at various projectile charge states. The experiment was performed using the recoil-ion time-of-flight technique. Projectile charge state dependence of the ionization yields was compared mainly with a model based on the giant dipole plasmon resonance (GDPR). In some cases, the continuum-distorted-wave-eikonal-initial-state (CDW-EIS) model which is normally applied for ion-atom collisions was also used as a reference. An excellent qualitative agreement between the experimental data for single and double ionization and the GDPR model predictions was found for all projectile charge states.

  18. Single and multiple ionization of C60 fullerenes and collective effects in collisions with highly charged C, F, and Si ions with energy 3 MeV/u

    International Nuclear Information System (INIS)

    Kelkar, A. H.; Kadhane, U.; Misra, D.; Tribedi, L. C.; Gulyas, L.

    2010-01-01

    We have measured absolute cross sections for single, double, triple, and quadruple ionization of C 60 in collisions with 3 MeV/u C, F, and Si projectile ions at various projectile charge states. The experiment was performed using the recoil-ion time-of-flight technique. Projectile charge state dependence of the ionization yields was compared mainly with a model based on the giant dipole plasmon resonance (GDPR). In some cases, the continuum-distorted-wave-eikonal-initial-state (CDW-EIS) model which is normally applied for ion-atom collisions was also used as a reference. An excellent qualitative agreement between the experimental data for single and double ionization and the GDPR model predictions was found for all projectile charge states.

  19. Single-electron charging effects and implications for tunneling measurements of the high-T/sub c/ superconductors

    International Nuclear Information System (INIS)

    Barner, J.B.; Honkanen, M.J.; Ruggiero, S.T.; Mullen, K.; Ben-Jacob, E.; Pelton, A.R.; Michigan Univ., Ann Arbor, MI

    1989-01-01

    The authors present a theory for the dynamics of two voltage-biased, ultra-small-capacitance tunnel junctions connected in series when one or more electrodes are superconducting and experiments performed on parallel arrays of such junctions. Using the semiclassical model, they find that the I-V characteristics display steps and therefore multiple peaks in dI/dV, corresponding to the time-average occupation of the interjunction region by integral numbers of electrons. The voltage at which the first step is located depends on the superconducting gap, Δ(T), and the capacitances of the junctions. The spacing between subsequent steps depends solely on the capacitances. They discuss electron tunneling results performed on metal/Al/sub 2/O/sub 3//2-10 nm-diameter metal particles/Al/sub 2/O/sub 3//metal junctions where this multiple-peak structure is observed. They present preliminary tunneling results in junctions employing Pb-particles, where they observe a shift of the peaks when the sample is cooled below T/sub c/ of Pb consistent with theory. Taken together, these results indicate that the multiple-peak structure commonly observed in tunneling data of high-T/sub c/ oxide superconductors can be explained in terms of charging effects in a material with a single superconducting gap. Finally, they discuss possible applications in a new type of transistor element

  20. Charge transport and glassy dynamics of poly(ethylene oxide)-based single-ion conductors under geometrical confinement

    Science.gov (United States)

    Runt, James; Iacob, Ciprian

    2015-03-01

    Segmental and local dynamics as well as charge transport are investigated in a series of poly(ethylene oxide)-based single-ion conductors (ionomers) with varying counterions (Li +, Na +) confined in uni-directional nanoporous silica membranes. The dynamics are explored over a wide frequency and temperature range by broadband dielectric relaxation spectroscopy. Slowing of segmental dynamics and a decrease in dc conductivity (strongly coupled with segmental relaxation) of the confined ionomers are associated with surface effects - resulting from interfacial hydrogen bonding between the host nanoporous silica membrane and the guest ionomers. These effects are significantly reduced or eliminated upon pore surface modification through silanization. The primary transport properties for the confined ionomers decrease by about one decade compared to the bulk ionomer. A model assuming reduced mobility of an adsorbed layer at the pore wall/ionomer interface is shown to provide a quantitative explanation for the decrease in effective transport quantities in non-silanized porous silica membranes. Additionally, the effect of confinement on ion aggregation in ionomers by using X-ray scattering will also be discussed. Supported by the National Science Foundation, Polymers Program.

  1. Molecular recognition of AT-DNA sequences by the induced CD pattern of dibenzotetraaza[14]annulene (DBTAA)-adenine derivatives.

    Science.gov (United States)

    Stojković, Marijana Radić; Skugor, Marko; Dudek, Lukasz; Grolik, Jarosław; Eilmes, Julita; Piantanida, Ivo

    2014-01-01

    An investigation of the interactions of two novel and several known DBTAA-adenine conjugates with double-stranded DNA and RNA has revealed the DNA/RNA groove as the dominant binding site, which is in contrast to the majority of previously studied DBTAA analogues (DNA/RNA intercalators). Only DBTAA-propyladenine conjugates revealed the molecular recognition of AT-DNA by an ICD band pattern > 300 nm, whereas significant ICD bands did not appear for other ds-DNA/RNA. A structure-activity relation for the studied series of compounds showed that the essential structural features for the ICD recognition are a) the presence of DNA-binding appendages (adenine side chain and positively charged side chain) on both DBTAA side chains, and b) the presence of a short propyl linker, which does not support intramolecular aromatic stacking between DBTAA and adenine. The observed AT-DNA-ICD pattern differs from previously reported ss-DNA (poly dT) ICD recognition by a strong negative ICD band at 350 nm, which allows for the dynamic differentiation between ss-DNA (poly dT) and coupled ds-AT-DNA.

  2. Active and fast charge-state switching of single NV centres in diamond by in-plane Al-Schottky junctions

    Directory of Open Access Journals (Sweden)

    Christoph Schreyvogel

    2016-11-01

    Full Text Available In this paper, we demonstrate an active and fast control of the charge state and hence of the optical and electronic properties of single and near-surface nitrogen-vacancy centres (NV centres in diamond. This active manipulation is achieved by using a two-dimensional Schottky-diode structure from diamond, i.e., by using aluminium as Schottky contact on a hydrogen terminated diamond surface. By changing the applied potential on the Schottky contact, we are able to actively switch single NV centres between all three charge states NV+, NV0 and NV− on a timescale of 10 to 100 ns, corresponding to a switching frequency of 10–100 MHz. This switching frequency is much higher than the hyperfine interaction frequency between an electron spin (of NV− and a nuclear spin (of 15N or 13C for example of 2.66 kHz. This high-frequency charge state switching with a planar diode structure would open the door for many quantum optical applications such as a quantum computer with single NVs for quantum information processing as well as single 13C atoms for long-lifetime storage of quantum information. Furthermore, a control of spectral emission properties of single NVs as a single photon emitters – embedded in photonic structures for example – can be realized which would be vital for quantum communication and cryptography.

  3. Charge exchange, surface-induced dissociation and reactions of doubly charged molecular ions SF42+ upon impact on a stainless steel surface: A comparison with surface-induced dissociation of singly charged SF4+ molecular ions

    Czech Academy of Sciences Publication Activity Database

    Feketeová, L.; Grill, V.; Zappa, F.; Endstrasser, N.; Rasul, B.; Herman, Zdeněk; Scheier, P.; Märk, T. D.

    2008-01-01

    Roč. 276, č. 1 (2008), s. 37-42 ISSN 1387-3806 Institutional research plan: CEZ:AV0Z40400503 Keywords : doubly charged ion * surface-induced dissociations * surface-induced reaction * charge exchange Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.445, year: 2008

  4. Irradiation of zinc single crystal with 500 keV singly-charged carbon ions: surface morphology, structure, hardness, and chemical modifications

    Science.gov (United States)

    Waqas Khaliq, M.; Butt, M. Z.; Saleem, Murtaza

    2017-07-01

    Cylindrical specimens of (1 0 4) oriented zinc single crystal (diameter  =  6 mm and length  =  5 mm) were irradiated with 500 keV C+1 ions with the help of a Pelletron accelerator. Six specimens were irradiated in an ultra-high vacuum (~10‒8 Torr) with different ion doses, namely 3.94  ×  1014, 3.24  ×  1015, 5.33  ×  1015, 7.52  ×  1015, 1.06  ×  1016, and 1.30  ×  1016 ions cm-2. A field emission scanning electron microscope (FESEM) was utilized for the morphological study of the irradiated specimens. Formation of nano- and sub-micron size rods, clusters, flower- and fork-like structures, etc, was observed. Surface roughness of the irradiated specimens showed an increasing trend with the ions dose. Energy dispersive x-ray spectroscopy (EDX) helped to determine chemical modifications in the specimens. It was found that carbon content varied in the range 22.86-31.20 wt.% and that oxygen content was almost constant, with an average value of 10.16 wt.%. The balance content was zinc. Structural parameters, i.e. crystallite size and lattice strain, were determined by Williamson-Hall analysis using x-ray diffraction (XRD) patterns of the irradiated specimens. Both crystallite size and lattice strain showed a decreasing trend with the increasing ions dose. A good linear relationship between crystallite size and lattice strain was observed. Surface hardness depicted a decreasing trend with the ions dose and followed an inverse Hall-Petch relation. FTIR spectra of the specimens revealed that absorption bands gradually diminish as the dose of singly-charged carbon ions is increased from 3.94  ×  1014 ions cm-1 to 1.30  ×  1016 ions cm-1. This indicates progressive deterioration of chemical bonds with the increase in ion dose.

  5. Study of Charge-Dependent Transport and Toxicity of Peptide-Functionalized Silver Nanoparticles Using Zebrafish Embryos and Single Nanoparticle Plasmonic Spectroscopy

    Science.gov (United States)

    Lee, Kerry J.; Browning, Lauren M.; Nallathamby, Prakash D.; Xu, Xiao-Hong Nancy

    2013-01-01

    Nanomaterials possess unusually high surface area-to-volume ratios, and surface-determined physicochemical properties. It is essential to understand their surface-dependent toxicity in order to rationally design biocompatible nanomaterials for a wide variety of applications. In this study, we have functionalized the surfaces of silver nanoparticles (Ag NPs, 11.7 ± 2.7 nm in diameters) with three biocompatible peptides (CALNNK, CALNNS, CALNNE) to prepare positively (Ag-CALNNK NPs+ζ), negatively (Ag-CALNNS NPs−2ζ), and more negatively charged NPs (Ag-CALNNE NPs−4ζ), respectively. Each peptide differs in a single amino acid at its C-terminus, which minimizes the effects of peptide sequences and serves as a model molecule to create positive, neutral and negative charges on the surface of the NPs at pH 4–10. We have studied their charge-dependent transport into early-developing (cleavage-stage) zebrafish embryos and their effects on embryonic development using dark-field optical microscopy and spectroscopy (DFOMS). We found that all three Ag-peptide NPs passively diffused into the embryos via their chorionic pore canals, and stayed inside the embryos throughout their entire development (120 h), showing charge-independent diffusion modes and charge-dependent diffusion coefficients. Notably, the NPs create charge-dependent toxic effects on embryonic development, showing that the Ag-CALNNK NPs+ζ (positively charged) are the most biocompatible while the Ag-CALNNE NPs–4ζ (more negatively charged) are the most toxic. By comparing with our previous studies of the same sized citrated Ag and Au NPs, the Ag-peptide NPs are much more biocompatible than the citrated Ag NPs, and nearly as biocompatible as the Au NPs, showing the dependence of nanotoxicity upon the surface charges, surface functional groups and chemical compositions of the NPs. This study also demonstrates powerful applications of single NP plasmonic spectroscopy for quantitative analysis of single NPs

  6. ANISOTROPY EFFECTS IN SINGLE-ELECTRON TRANSFER BETWEEN LASER-EXCITED ATOMS AND HIGHLY-CHARGED IONS

    NARCIS (Netherlands)

    Recent collision experiments are reviewed in which one-electron transfer between laser excited target atoms and (highly charged) keV-ions has been studied. Especially results showing a dependence of the charge exchange on the initial target orbital alignment are discussed. The question to what

  7. Gum Acacia Improves Renal Function and Ameliorates Systemic Inflammation, Oxidative and Nitrosative Stress in Streptozotocin-Induced Diabetes in Rats with Adenine-Induced Chronic Kidney Disease

    Directory of Open Access Journals (Sweden)

    Mohammed Al Za’abi

    2018-03-01

    Full Text Available Background/Aims: The effect of treatment with gum acacia (GA, a prebiotic shown previously to ameliorate chronic kidney disease (CKD, in diabetic and non – diabetic rats with adenine – induced CKD has been investigated using several conventional and novel physiological, biochemical, and histopathological parameters. Methods: Diabetes mellitus was induced in rats by a single injection of streptozotocin (STZ. Diabetic and non – diabetic rats were randomly divided into several groups, and given either normal food or food mixed with adenine (0.25% w/w, for five weeks to induce CKD. Some of these groups were also concomitantly treated orally with GA in the drinking water (15% w/w. Results: Rats fed adenine alone exhibited physiological (decreased body weight, increased food and water intake and urine output, biochemical (increase in urinary albumin/creatinine ratio, plasma urea and, creatinine, indoxyl sulfate and phosphorus, inflammatory biomarkers (increased in neutrophil gelatinase-associated lipocalin, transforming growth factor beta -1, tumor necrosis factor alpha, adiponectin, cystatin C and interleukin-1β, oxidative biomarkers (8-isoprostane, 8 -hydroxy -2-deoxy guanosine, nitrosative stress biomarkers (nitrite and nitrate and histopathological (increase in tubular necrosis and fibrosis signs of CKD. STZ - induced diabetes alone worsened most of the renal function tests measured. Administration of adenine in STZ – diabetic rats further worsened the renal damage induced by adenine alone. GA significantly ameliorated the renal actions of adenine and STZ, given either singly or in combination, especially with regards to the histopathological damage. Conclusion: GA is a useful dietary agent in attenuating the progression of CKD in rats with streptozotocin-induced diabetes.

  8. Studies on mixed ligand complexes of adenine and xanthine with some rare earth ions

    International Nuclear Information System (INIS)

    Rastogi, P.R.; Singh, Mamta; Nayan, Ram

    1993-01-01

    Interactions of 6-aminopurine (adenine, HA) and 2,6-dihydroxypurine (xanthine, HB) with trivalent rare earth ions Y, Tb, Dy, Ho, Er and Tm, have been studied by pH-titration methods in aqueous solution at 20 o (μ = 0.1 M KNO 3 ). The ligands in their mixtures with tripositive rare earth ions (M 3+ ) form a number of mixed ligand complexes, M 3+ -adenine-xanthine, M 3+ -(adenine) 2 -xanthine, M 3+ -adenine-(xanthine) 2 in addition to the binary complexes, M 3+ -(adenine), M 3+ -(adenine) 2 , M 3+ -(adenine) 3 , M 3+ -(xanthine), M 3+ -(xanthine) 2 and M 3+ -(xanthine) 3 . The stability constants of these complexes have been evaluated and the results discussed. (author). 13 refs., 1 fig., 1 tab

  9. Voltammetric study of adenine complex with copper on mercury electrode

    Czech Academy of Sciences Publication Activity Database

    Jelen, František; Kouřilová, Alena; Hasoň, Stanislav; Kizek, R.; Trnková, L.

    2009-01-01

    Roč. 21, 3-5 (2009), s. 439-444 ISSN 1040-0397 R&D Projects: GA AV ČR(CZ) IAA100040602; GA AV ČR(CZ) IAA400040804; GA AV ČR(CZ) KAN200040651 Institutional research plan: CEZ:AV0Z50040507; CEZ:AV0Z50040702 Keywords : cyclic voltammetry * elimination voltammetry * copper-adenine complex Subject RIV: BO - Biophysics Impact factor: 2.630, year: 2009

  10. Structural effects on charge order in single-layered manganites R{sub 1-x}A{sub 1+x}MnO{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Engelmayer, Johannes; Ulbrich, Holger; Weber, Lisa; Braden, Markus; Lorenz, Thomas [II. Physikalisches Institut, Universitaet zu Koeln (Germany)

    2015-07-01

    Single-layered manganites show a complex interplay between charge, orbital, and magnetic degrees of freedom. For half-doped (x=1/2) R{sub 1-x}A{sub 1+x}MnO{sub 4} (R=Pr,La; A=Ca,Sr) the so-called Goodenough model is well established. This model proposes a site-centered charge order with a checkerboard pattern of Mn{sup 3+} and Mn{sup 4+} ions accompanied by an orbital order. Furthermore a magnetic order develops with ferromagnetic three-spin zig-zag chains and antiferromagnetic interchain coupling. For x=2/3 the charge order appears as stripe pattern with two adjacent stripes of Mn{sup 4+} ions alternating with a single stripe of Mn{sup 3+} ions, while in the magnetically ordered state four-spin zig-zag chains arise. For a deeper understanding of the emergence of charge order, it is appropriate to vary on the one hand the elements R and A while keeping the doping level x constant - involving structural changes at fixed charge carrier density - and on the other hand change the doping level with the same R and A. Therefore various single crystals of R{sub 1-x}A{sub 1+x}MnO{sub 4} with R=(Pr, Nd, Sm, Tb), A=(Ca, Sr) and 0.5 ≤ x ≤ 0.7 were grown and their structural parameters were determined by X-ray diffraction. Based on measurements of resistivity, magnetization, specific heat, and crystal structure we discuss the influence of structural variations on the ordering temperature.

  11. Ordered Single-Crystalline Anatase TiO2Nanorod Clusters Planted on Graphene for Fast Charge Transfer in Photoelectrochemical Solar Cells.

    Science.gov (United States)

    Wang, Yang; Liu, Xueqin; Li, Zhen; Cao, Ya; Li, Yinchang; Liu, Xupo; Jia, Songru; Zhao, Yanli

    2017-07-01

    Achieving efficient charge transport is a great challenge in nanostructured TiO 2 -electrode-based photoelectrochemical cells. Inspired by excellent directional charge transport and the well-known electroconductibility of 1D anatase TiO 2 nanostructured materials and graphene, respectively, planting ordered, single-crystalline anatase TiO 2 nanorod clusters on graphene sheets (rGO/ATRCs) via a facial one-pot solvothermal method is reported. The hierarchical rGO/ATRCs nanostructure can serve as an efficient light-harvesting electrode for dye-sensitized solar cells. In addition, the obtained high-crystallinity anatase TiO 2 nanorods in rGO/ATRCs possess a lower density of trap states, thus facilitating diffusion-driven charge transport and suppressing electron recombination. Moreover, the novel architecture significantly enhances the trap-free charge diffusion coefficient, which contributes to superior electron mobility properties. By virtue of more efficient charge transport and higher energy conversion efficiency, the rGO/ATRCs developed in this work show significant advantages over conventional rGO-TiO 2 nanoparticle counterparts in photoelectrochemical cells. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Dynamics of Charged Excitons and Biexcitons in CsPbBr3 Perovskite Nanocrystals Revealed by Femtosecond Transient-Absorption and Single-Dot Luminescence Spectroscopy.

    Science.gov (United States)

    Yarita, Naoki; Tahara, Hirokazu; Ihara, Toshiyuki; Kawawaki, Tokuhisa; Sato, Ryota; Saruyama, Masaki; Teranishi, Toshiharu; Kanemitsu, Yoshihiko

    2017-04-06

    Metal-halide perovskite nanocrystals (NCs) are promising photonic materials for use in solar cells, light-emitting diodes, and lasers. The optoelectronic properties of these devices are determined by the excitons and exciton complexes confined in their NCs. In this study, we determined the relaxation dynamics of charged excitons and biexcitons in CsPbBr 3 NCs using femtosecond transient-absorption (TA), time-resolved photoluminescence (PL), and single-dot second-order photon correlation spectroscopy. Decay times of ∼40 and ∼200 ps were obtained from the TA and PL decay curves for biexcitons and charged excitons, respectively, in NCs with an average edge length of 7.7 nm. The existence of charged excitons even under weak photoexcitation was confirmed by the second-order photon correlation measurements. We found that charged excitons play a dominant role in luminescence processes of CsPbBr 3 NCs. Combining different spectroscopic techniques enabled us to clarify the dynamical behaviors of excitons, charged excitons, and biexcitons.

  13. Single neutral pion production by charged-current ν¯μ interactions on hydrocarbon at 〈Eν〉=3.6 GeV

    Directory of Open Access Journals (Sweden)

    T. Le

    2015-10-01

    Full Text Available Single neutral pion production via muon antineutrino charged-current interactions in plastic scintillator (CH is studied using the MINERvA detector exposed to the NuMI low-energy, wideband antineutrino beam at Fermilab. Measurement of this process constrains models of neutral pion production in nuclei, which is important because the neutral-current analog is a background for ν¯e appearance oscillation experiments. The differential cross sections for π0 momentum and production angle, for events with a single observed π0 and no charged pions, are presented and compared to model predictions. These results comprise the first measurement of the π0 kinematics for this process.

  14. Single-molecule conductance of a chemically modified, π-extended tetrathiafulvalene and its charge-transfer complex with F4TCNQ.

    Science.gov (United States)

    García, Raúl; Herranz, M Ángeles; Leary, Edmund; González, M Teresa; Bollinger, Gabino Rubio; Bürkle, Marius; Zotti, Linda A; Asai, Yoshihiro; Pauly, Fabian; Cuevas, Juan Carlos; Agraït, Nicolás; Martín, Nazario

    2015-01-01

    We describe the synthesis and single-molecule electrical transport properties of a molecular wire containing a π-extended tetrathiafulvalene (exTTF) group and its charge-transfer complex with F4TCNQ. We form single-molecule junctions using the in situ break junction technique using a homebuilt scanning tunneling microscope with a range of conductance between 10 G0 down to 10(-7) G0. Within this range we do not observe a clear conductance signature of the neutral parent molecule, suggesting either that its conductance is too low or that it does not form a stable junction. Conversely, we do find a clear conductance signature in the experiments carried out on the charge-transfer complex. Due to the fact we expected this species to have a higher conductance than the neutral molecule, we believe this supports the idea that the conductance of the neutral molecule is very low, below our measurement sensitivity. This idea is further supported by theoretical calculations. To the best of our knowledge, these are the first reported single-molecule conductance measurements on a molecular charge-transfer species.

  15. Sulfur and adenine metabolisms are linked, and both modulate sulfite resistance in wine yeast.

    Science.gov (United States)

    Aranda, Agustín; Jiménez-Martí, Elena; Orozco, Helena; Matallana, Emilia; Del Olmo, Marcellí

    2006-08-09

    Sulfite treatment is the most common way to prevent grape must spoilage in winemaking because the yeast Saccharomyces cerevisiae is particularly resistant to this chemical. In this paper we report that sulfite resistance depends on sulfur and adenine metabolism. The amount of adenine and methionine in a chemically defined growth medium modulates sulfite resistance of wine yeasts. Mutations in the adenine biosynthetic pathway or the presence of adenine in a synthetic minimal culture medium increase sulfite resistance. The presence of methionine has the opposite effect, inducing a higher sensitivity to SO(2). The concentration of methionine, adenine, and sulfite in a synthetic grape must influences the progress of fermentation and at the transcriptional level the expression of genes involved in sulfur (MET16), adenine (ADE4), and acetaldehyde (ALD6) metabolism. Sulfite alters the pattern of expression of all these genes. This fact indicates that the response to this stress is complex and involves several metabolic pathways.

  16. Effects of submaximal exercise on adenine nucleotide concentrations in skeletal muscle fibers of horses with polysaccharide storage myopathy.

    Science.gov (United States)

    Annandale, Erin J; Valberg, Stephanie J; Essen-Gustavsson, Birgitta

    2005-05-01

    To determine whether disruption of adenine triphosphate (ATP) regeneration and subsequent adenine nucleotide degradation are potential mechanisms for rhabdomyolysis in horses with polysaccharide storage myopathy (PSSM) performing submaximal exercise. 7 horses with PSSM and 4 control horses. Horses with PSSM performed 2-minute intervals of a walk and trot exercise on a treadmill until muscle cramping developed. Control horses exercised similarly for 20 minutes. Serum creatine kinase (CK) activity was measured 4 hours after exercise. Citrate synthase (CS), 3-OH-acylCoA dehydrogenase, and lactate dehydrogenase activities prior to exercise and glucose-6-phosphate (G-6-P) and lactate concentrations before and after exercise were measured in gluteal muscle specimens. Adenine triphosphate, diphosphate (ADP), monophosphate (AMP), and inosine monophosphate (IMP) concentrations were measured before and after exercise in whole muscle, single muscle fibers, and pooled single muscle fibers. Serum CK activity ranged from 255 to 22,265 U/L in horses with PSSM and 133 to 278 U/L in control horses. Muscle CS activity was lower in horses with PSSM, compared with control horses. Muscle G-6-P lactate, ATP, ADP, and AMP concentrations in whole muscle did not change with exercise in any horses. Concentration of IMP increased with exercise in whole muscle, pooled muscle fibers, and single muscle fibers in horses with PSSM. Large variations in ATP and IMP concentrations were observed within single muscle fibers. Increased IMP concentration without depletion of ATP in individual muscle fibers of horses with PSSM during submaximal exercise indicates an energy imbalance that may contribute to the development of exercise intolerance and rhabdomyolysis.

  17. Electric field reduced charging energies and two-electron bound excited states of single donors in silicon

    NARCIS (Netherlands)

    Rahman, R.; Lansbergen, G.P.; Verduijn, J.; Tettamanzi, G.C.; Park, S.H.; Collaert, N.; Biesemans, S.; Klimeck, G.; Hollenberg, L.C.L.; Rogge, S.

    2011-01-01

    We present atomistic simulations of the D0 to D? charging energies of a gated donor in silicon as a function of applied fields and donor depths and find good agreement with experimental measurements. A self-consistent field large-scale tight-binding method is used to compute the D? binding energies

  18. Doubly versus Singly Positively Charged Oxygen Ions Back-Scattering from a Silicon Surface under Dynamic O2+ Bombardment

    Czech Academy of Sciences Publication Activity Database

    Franzreb, K.; Williams, P.; Lörinčík, Jan; Šroubek, Zdeněk

    203-204, 1/4 (2003), s. 39-42 ISSN 0169-4332 Institutional research plan: CEZ:AV0Z2067918; CEZ:AV0Z4040901 Keywords : low-energy ion scattering * doubly charged ions * molecular orbital Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.284, year: 2003

  19. Mass-charge-heat coupled transfers in a single cell of a proton exchange membrane fuel cell; Transferts couples masse-charge-chaleur dans une cellule de pile a combustible a membrane polymere

    Energy Technology Data Exchange (ETDEWEB)

    Ramousse, J.

    2005-11-15

    Understanding and modelling of coupled mass, charges and heat transfers phenomena are fundamental to analyze the electrical behaviour of the system. The aim of the present model is to describe electrical performances of a PEFMC according to the fluidic and thermal operating conditions. The water content of the membrane and the water distribution in the single cell are estimated according to the coupled simulations of mass transport in the thickness of the single cell and in the feeding channels of the bipolar plates. A microscopic model of a Gas Diffusion Electrode is built up to describe charges transfer phenomena occurring at the electrodes. Completed by a study of heat transfer in the Membrane Electrode Assembly, conditions and preferential sites of water vapor condensation can be highlighted. A set of measurements of the effective thermal conductivity of carbon felts used in fuel cells as porous backing layers have also been performed. Although the value of this parameter is essential for the study of heat transfer, it is still under investigation because of the strong thermal anisotropy of the medium. (author)

  20. Charge-carrier mobilities in Cd(0.8)Zn(0.2)Te single crystals used as nuclear radiation detectors

    Science.gov (United States)

    Burshtein, Z.; Jayatirtha, H. N.; Burger, A.; Butler, J. F.; Apotovsky, B.; Doty, F. P.

    1993-01-01

    Charge-carrier mobilities were measured for the first time in Cd(0.8)Zn(0.2)Te single crystals using time-of-flight measurements of charge carriers produced by short (10 ns) light pulses from a frequency-doubled Nd:YAG laser (532 nm). The electron mobility displayed a T exp -1.1 dependence on the absolute temperature T in the range 200-320 K, with a room-temperature mobility of 1350 sq cm/V s. The hole mobility displayed a T exp -2.0 dependence in the same temperature range, with a room-temperature mobility of 120 sq cm/V s. Cd(0.8)Zn(0.2)Te appears to be a very favorable material for a room-temperature electronic nuclear radiation detector.

  1. Nonselective enrichment for yeast adenine mutants by flow cytometry

    Science.gov (United States)

    Bruschi, C. V.; Chuba, P. J.

    1988-01-01

    The expression of certain adenine biosynthetic mutations in the yeast Saccharomyces cerevisiae results in a red colony color. This phenomenon has historically provided an ideal genetic marker for the study of mutation, recombination, and aneuploidy in lower eukaryotes by classical genetic analysis. In this paper, it is reported that cells carrying ade1 and/or ade2 mutations exhibit primary fluorescence. Based on this observation, the nonselective enrichment of yeast cultures for viable adenine mutants by using the fluorescence-activated cell sorter has been achieved. The advantages of this approach over conventional genetic analysis of mutation, recombination, and mitotic chromosomal stability include speed and accuracy in acquiring data for large numbers of clones. By using appropriate strains, the cell sorter has been used for the isolation of both forward mutations and chromosomal loss events in S. cerevisiae. The resolving power of this system and its noninvasiveness can easily be extended to more complex organisms, including mammalian cells, in which analogous metabolic mutants are available.

  2. Nanoampere charge pump by single-electron ratchet using silicon nanowire metal-oxide-semiconductor field-effect transistor

    Science.gov (United States)

    Fujiwara, Akira; Nishiguchi, Katsuhiko; Ono, Yukinori

    2008-01-01

    Nanoampere single-electron pumping is presented at 20K using a single-electron ratchet comprising silicon nanowire metal-oxide-semiconductor field-effect transistors. The ratchet features an asymmetric potential with a pocket that captures single electrons from the source and ejects them to the drain. Directional single-electron transfer is achieved by applying one ac signal with the frequency up to 2.3GHz. We find anomalous shapes of current steps which can be ascribed to nonadiabatic electron capture.

  3. Electron Spin Resonance study of charge trapping in α-ZnMoO.sub.4./sub. single crystal scintillator

    Czech Academy of Sciences Publication Activity Database

    Buryi, Maksym; Spassky, D.A.; Hybler, Jiří; Laguta, Valentyn; Nikl, Martin

    2015-01-01

    Roč. 47, Sep (2015), 244-250 ISSN 0925- 3467 R&D Projects: GA MŠk LO1409; GA MŠk(CZ) LM2011029; GA ČR GAP204/12/0805 Institutional support: RVO:68378271 Keywords : Electron Spin Resonance * scintillator * charge traps * zinc molybdate Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.183, year: 2015

  4. The effect of swimming exercise on adenine-induced kidney disease in rats, and the influence of curcumin or lisinopril thereon.

    Directory of Open Access Journals (Sweden)

    Badreldin H Ali

    Full Text Available Patients with chronic kidney disease (CKD have been reported to benefit from different types of exercises. It has also been shown that the ACE inhibitor lisinopril, and the natural product curcumin are also beneficial in different models of CKD in rats. We assessed the influence of moderate swimming exercise (SE on rats with adenine-induced CKD, and tested the possible effects of lisinopril and/or curcumin thereon using several physiological, biochemical, histopathological and immunohistochemical parameters. Rats (either sedentary or subjected to SE were randomly divided into several groups, and given for five weeks either normal food or food mixed with adenine (0.25% w/w to induce CKD. Some of these groups were also concomitantly treated orally with curcumin (75 mg/kg, or lisinopril (10 mg/kg and were subjected to moderate SE (45 min/day three days each week. Rats fed adenine showed the typical biochemical, histopathological signs of CKD such as elevations in blood pressure, urinary albumin / creatinine ratio, and plasma urea, creatinine, indoxyl sulfate and phosphorus. SE, curcumin or lisinopril, given singly, significantly ameliorated all the adenine-induced actions. Administering curcumin or lisinopril with SE improved the histopathology of the kidneys, a salutary effect not seen with SE alone. Combining SE to the nephroprotective agents' curcumin or lisinopril might offer additional nephroprotection.

  5. Predictive DFT-based approaches to charge and spin transport in single-molecule junctions and two-dimensional materials: successes and challenges.

    Science.gov (United States)

    Quek, Su Ying; Khoo, Khoong Hong

    2014-11-18

    CONSPECTUS: The emerging field of flexible electronics based on organics and two-dimensional (2D) materials relies on a fundamental understanding of charge and spin transport at the molecular and nanoscale. It is desirable to make predictions and shine light on unexplained experimental phenomena independently of experimentally derived parameters. Indeed, density functional theory (DFT), the workhorse of first-principles approaches, has been used extensively to model charge/spin transport at the nanoscale. However, DFT is essentially a ground state theory that simply guarantees correct total energies given the correct charge density, while charge/spin transport is a nonequilibrium phenomenon involving the scattering of quasiparticles. In this Account, we critically assess the validity and applicability of DFT to predict charge/spin transport at the nanoscale. We also describe a DFT-based approach, DFT+Σ, which incorporates corrections to Kohn-Sham energy levels based on many-electron calculations. We focus on single-molecule junctions and then discuss how the important considerations for DFT descriptions of transport can differ in 2D materials. We conclude that when used appropriately, DFT and DFT-based approaches can play an important role in making predictions and gaining insight into transport in these materials. Specifically, we shall focus on the low-bias quasi-equilibrium regime, which is also experimentally most relevant for single-molecule junctions. The next question is how well can the scattering of DFT Kohn-Sham particles approximate the scattering of true quasiparticles in the junction? Quasiparticles are electrons (holes) that are surrounded by a constantly changing cloud of holes (electrons), but Kohn-Sham particles have no physical significance. However, Kohn-Sham particles can often be used as a qualitative approximation to quasiparticles. The errors in standard DFT descriptions of transport arise primarily from errors in the Kohn-Sham energy levels

  6. Role of hyperfine interaction on electron spin optical orientation in charge-controlled InAs-GaAs single quantum dots

    International Nuclear Information System (INIS)

    Krebs, O.; Eble, B.; Lemaitre, A.; Kudelski, A.; Voisin, P.; Urbaszek, B.; Marie, X.; Amand, T.; Kowalik, K.

    2007-01-01

    We report on electron spin physics in a single charge-tunable self-assembled InAs/GaAs quantum dot. The hyperfine interaction between the optically oriented electron and nuclear spins leads to the polarization of the quantum dot nuclei. The sign of the resulting Overhauser-shift depends on the trion state X + or X - , and remarkably its strength does not vanish in zero magnetic field. This explains the quenching of X + spin relaxation under steady-state excitation polarization. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  7. First Measurement of the Muon Neutrino Charged Current Single Pion Production Cross Section on Water with the T2K Near Detector

    CERN Document Server

    Abe, K.

    2017-01-26

    The T2K off-axis near detector, ND280, is used to make the first differential cross section measurements of muon neutrino charged current single positive pion production on a water target at energies ${\\sim}0.8$~GeV. The differential measurements are presented as a function of muon and pion kinematics, in the restricted phase-space defined by $p_{\\pi^+}>200$MeV/c, $p_{\\mu^-}>200$MeV/c, $\\cos \\theta_{\\pi^+}>0.3$ and $\\cos \\theta_{\\mu^-}>0.3$. The total flux integrated $\

  8. Bianthrone in a Single-Molecule Junction: Conductance Switching with a Bistable Molecule Facilitated by Image Charge Effects

    DEFF Research Database (Denmark)

    Bjørnholm, Thomas

    2010-01-01

    isomerization events. Temperature dependence of the switching rate allows for an estimate of the activation energy of the process, on the order of 120 +/- 50 meV. Quantum-chemical calculations of the potential energy relief of neutral bianthrone and its anion, including identification of transition states......, yields the isolated molecule isomerization barriers too high vs the previous estimate, though compatible with previous experimental studies in solution. Nevertheless, we show that the attraction of the anion in the vicinity of the metal surface by its image charge can change the energetic landscape...

  9. Prevention of injury by resveratrol in a rat model of adenine-induced ...

    African Journals Online (AJOL)

    The effect of 10, 15, and 20 mg/kg doses of resveratrol on the levels of parathyroid hormone, phosphorous, and fibroblast growth factor-23 (FGF-23) in rat urine samples after 2 months of adenine administration were analyzed using an auto-analyzer. Results: Resveratrol treatment significantly inhibited the adenine-mediated ...

  10. Surface-Enhanced Raman Scattering of the Complexes of Silver with Adenine and dAMP

    NARCIS (Netherlands)

    Otto, Cornelis; Hoeben, F.P.; Hoeben, F.P.; Greve, Jan

    1991-01-01

    The behaviour of adenine and 2'-deoxyadenosine-5'-monophosphate (dAMP) at positive surface potentials of a silver working electrode was investigated using surface-enhanced Raman scattering (SERS). The use of positive potentials in the presence of adenine or dAMP leads to a rapid accumulation of an

  11. Suppression of feline immunodeficiency virus infection in vivo by 9-(2-phosphonomethoxyethyl)adenine

    NARCIS (Netherlands)

    Horzinek, M.C.; Egberink, H.F.; Borst, M.; Niphuis, H.; Balzarini, J.; Neu, H.; Schellekens, H.; Clercq, H. de; Koolen, M.J.M.

    1990-01-01

    The acyclic purine nucleoside analogue 9-(2-phosphonomethoxyethyl)adenine [PMEA; formerly referred to as 9-(2-phosphonylmethoxyethyl)adenine] is a potent and selective inhibitor of human immunodeficiency virus replication in vitro and of Moloney murine sarcoma virus-induced tumor formation in mice.

  12. The family of N -adenine: New entry for adenine–benzamide ...

    Indian Academy of Sciences (India)

    sisting linker, reactive functionality and adenine nucleo- base 1, 2 and 3 were synthesized as described below. Adenine derivatives 7 and 12 were synthesized accord- ing to slightly modified literature procedures and char- acterized spectroscopically.28,29 Boc-NH(CH2CH2O)2-. CH2CH2NH2 4 was synthesized according ...

  13. IR spectroscopy of isolated neutral and protonated adenine and 9-methyladenine

    NARCIS (Netherlands)

    van Zundert, G. C. P.; Jaeqx, S.; Berden, G.; Bakker, J.M.; Kleinermanns, K.; Oomens, J.; Rijs, A.M.

    2011-01-01

    IR spectroscopy is employed to study isolated adenine and its derivative 9-methyladenine in both their neutral and protonated forms. The IR spectra of neutral adenine and 9-methyladenine are measured in a molecular beam expansion via IR-UV ion-dip spectroscopy in the 525 to 1750 cm−1 region. For

  14. IR Spectroscopy of Isolated Neutral and Protonated Adenine and 9-Methyladenine

    NARCIS (Netherlands)

    van Zundert, G. C. P.; Jaeqx, S.; G. Berden,; Bakker, J. M.; Kleinermanns, K.; Oomens, J.; Rijs, A. M.

    2011-01-01

    IR spectroscopy is employed to study isolated adenine and its derivative 9-methyladenine in both their neutral and protonated forms. The IR spectra of neutral adenine and 9-methyladenine are measured in a molecular beam expansion via IR-UV ion-dip spectroscopy in the 525 to 1750 cm(-1) region. For

  15. Threshold voltage variation depending on single grain boundary and stored charges in an adjacent cell for vertical silicon–oxide–nitride–oxide–silicon NAND flash memory

    Science.gov (United States)

    Oh, Hyeongwan; Kim, Jiwon; Baek, Rock-Hyun; Lee, Jeong-Soo

    2018-04-01

    The effects of single grain boundary (SGB) position and stored electron charges in an adjacent cell in silicon–oxide–nitride–oxide–silicon (SONOS) structures on the variations of threshold voltage (V th) were investigated using technology computer-aided design (TCAD) simulation. As the bit line voltage increases, the SGB position causing the maximum V th variation was shifted from the center to the source side in the channel, owing to the drain-induced grain barrier lowering effect. When the SGB is located in the spacer region, the potential interaction from both the SGB and the stored electron charges in the adjacent cell becomes significant and thus resulting in larger V th variation. In contrast, when the SGB is located at the center of the channel, the peak position of potential barrier is shifted to the center, so that the influence of the adjacent cell is diminished. As the gate length is scaled down to 20 nm, the influence of stored charges in adjacent cells becomes significant, resulting in larger V th variations.

  16. Neutral and Charged Exciton Fine Structure in Single Lead Halide Perovskite Nanocrystals Revealed by Magneto-optical Spectroscopy.

    Science.gov (United States)

    Fu, Ming; Tamarat, Philippe; Huang, He; Even, Jacky; Rogach, Andrey L; Lounis, Brahim

    2017-05-10

    Revealing the crystal structure of lead halide perovskite nanocrystals is essential for the optimization of stability of these emerging materials in applications such as solar cells, photodetectors, and light-emitting devices. We use magneto-photoluminescence spectroscopy of individual perovskite CsPbBr 3 nanocrystals as a unique tool to determine their crystal structure, which imprints distinct signatures in the excitonic sublevels of charge complexes at low temperatures. At zero magnetic field, the identification of two classes of photoluminescence spectra, displaying either two or three sublevels in their exciton fine structure, shows evidence for the existence of two crystalline structures, namely tetragonal D 4h and orthorhombic D 2h phases. Magnetic field shifts, splitting, and coupling of the sublevels provide a determination of the diamagnetic coefficient and valuable information on the exciton g-factor and its anisotropic character. Moreover, this spectroscopic study reveals the optical properties of charged excitons and allows the extraction of the electron and hole g-factors for perovskite systems.

  17. Purine nucleotide synthesis from exogenous adenine and guanine in rodent small intestine

    International Nuclear Information System (INIS)

    Gross, C.J.; Karlberg, P.K.; Savaiano, D.A.

    1986-01-01

    14 C-Adenine and 14 C-guanine uptake was studied in isolated guinea pig enterocytes. Cells were incubated in Hank's buffer and separated from the medium by centrifugation through silicone oil into 1M PCA. Uptake was temperature and concentration dependent. Both compounds were incorporated into nucleotides as measured by HPLC and HVE. Adenine was more extensively incorporated into nucleotides than was guanine. Adenine nucleotides accounted for about 70% of the intracellular label after 30 min with a majority being ADP and ATP (medium concentration = 10 μM). Guanine nucleotides accounted for only 30% of the intracellular label after 30 min. Labeled intracellular free adenine or guanine were not detected. Significantly more guanine vs. adenine was converted to uric acid. After 30 min, 11.5 +/- 3.9% (n=3) and 83.0 +/- 8.4% (n=4) of the label was present as uric acid in the medium when adenine and guanine, respectively, were the substrate. After 1 min, 34.8 +/- 3.4% (n=4) of the label in the medium was present as uric acid when guanine was the substrate. Decreasing the concentration of adenine resulted in an increase in the percent of uric acid in the medium. 14 C-adenine (75 nmol) was injected into 1 gm segments of rat jejunum. After 5 min., segments were quickly flushed and the tissue homogenized in 1M PCA. Only uric acid was present after 5 min (n=6). In contrast, in animals fasted 3 to 5 days, less conversion to uric acid was observed in the intestinal content (50-80% of the same dose was still present as adenine after 5 min) and nucleotide formation was observed in the tissue. The results indicate that uric acid and nucleotide synthesis from exogenous adenine and guanine are concentration dependent and affected by nutritional state

  18. DFT calculations of the charged states of N@C60 and Fe4 single molecule magnets investigated in tunneling spectroscopy

    Science.gov (United States)

    Nossa, Javier; Islam, Fhokrul; Canali, Carlo; Pederson, Mark

    2012-02-01

    For device applications of single molecule magnets (SMMs) in high-density information storage and quantum-state control it is essential that the magnetic properties of the molecules remain stable under the influence of metallic contacts or surface environment. Recent tunneling experiments [1, 2] on N@C60 and Fe4 SMM have shown that these molecules preserve their magnetic characteristics when they are used as the central island of single-electron transistors. Although quantum spin models have been used extensively to study theoretically tunneling spectroscopy of SMMs, it has been shown recently that the orbital degrees of freedom, which is absent in spin models, can significantly affect the tunneling conductance [3]. In this work we present first-principles calculations of the neutral and charged states of N@C60 and Fe4 SMMs, and discuss a strategy to include their properties into a theory of quantum transport. We also present results of the magnetic anisotropy for the different charge states of Fe4 and discuss their relevance for experiments [2] in the sequential tunneling and cotunnelling regimes. [4pt] [1]. N. Roch et al., Phys. Rev. B 83, 081407 (2011). [0pt] [2]. A.S. Zyazin et al., Nano Lett. 10, 3307 (2010). [0pt] [3]. L. Michalak et al., Phys. Rev. Lett. 104, 017202 (2010).

  19. Bianthrone in a Single-Molecule Junction: Conductance Switching with a Bistable Molecule Facilitated by Image Charge Effects

    DEFF Research Database (Denmark)

    Bjørnholm, Thomas

    2010-01-01

    Bianthrone is a sterically hindered compound that exists in the form of two nonplanar isomers. Our experimental study of single-molecule junctions with bianthrone reveals persistent switching of electric conductance at low temperatures, which can be reasonably associated with molecular isomerizat...

  20. Giant plasmon excitation in single and double ionization of C{sub 60} by fast highly charged Si and O ions

    Energy Technology Data Exchange (ETDEWEB)

    Kelkar, A H; Kadhane, U; Misra, D; Tribedi, L C [Tata Institute of Fundamental Research, Colaba, Mumbai-5 (India)

    2007-09-15

    Se have investigated single and double ionization of C{sub 60} molecule in collisions with 2.33 MeV/u Si{sup q+} (q=6-14) and 3.125 MeV/u O{sup q+} (q=5-8) projectiles. The projectile charge state dependence of the single and double ionization yields of C{sub 60} are then compared to those for an ion-atom collision system using Ne gas as a target. A large difference between the gas and the cluster target behaviour was partially explained in terms of a model based on collective excitation namely the giant dipole plasmon resonance (GDPR). The qualitative agreement between the data and GDPR model prediction for single and double ionization signifies the importance of single and double plasmon excitations in the ionization process. A large deviation of the GDPR model for triple and quadruple ionization from the experimental data imply the importance of the other low impact parameter processes such as evaporation, fragmentation and a possible solid-like dynamical screening.

  1. Molecular recognition of AT-DNA sequences by the induced CD pattern of dibenzotetraaza[14]annulene (DBTAA)–adenine derivatives

    Science.gov (United States)

    Stojković, Marijana Radić; Škugor, Marko; Dudek, Łukasz; Grolik, Jarosław; Eilmes, Julita

    2014-01-01

    Summary An investigation of the interactions of two novel and several known DBTAA–adenine conjugates with double-stranded DNA and RNA has revealed the DNA/RNA groove as the dominant binding site, which is in contrast to the majority of previously studied DBTAA analogues (DNA/RNA intercalators). Only DBTAA–propyladenine conjugates revealed the molecular recognition of AT-DNA by an ICD band pattern > 300 nm, whereas significant ICD bands did not appear for other ds-DNA/RNA. A structure–activity relation for the studied series of compounds showed that the essential structural features for the ICD recognition are a) the presence of DNA-binding appendages (adenine side chain and positively charged side chain) on both DBTAA side chains, and b) the presence of a short propyl linker, which does not support intramolecular aromatic stacking between DBTAA and adenine. The observed AT-DNA-ICD pattern differs from previously reported ss-DNA (poly dT) ICD recognition by a strong negative ICD band at 350 nm, which allows for the dynamic differentiation between ss-DNA (poly dT) and coupled ds-AT-DNA. PMID:25246976

  2. Spontaneously formed high-performance charge-transport layers of organic single-crystal semiconductors on precisely synthesized insulating polymers

    Science.gov (United States)

    Makita, Tatsuyuki; Sasaki, Masayuki; Annaka, Tatsuro; Sasaki, Mari; Matsui, Hiroyuki; Mitsui, Chikahiko; Kumagai, Shohei; Watanabe, Shun; Hayakawa, Teruaki; Okamoto, Toshihiro; Takeya, Jun

    2017-04-01

    Charge-transporting semiconductor layers with high carrier mobility and low trap-density, desired for high-performance organic transistors, are spontaneously formed as a result of thermodynamic phase separation from a blend of π-conjugated small molecules and precisely synthesized insulating polymers dissolved in an aromatic solvent. A crystal film grows continuously to the size of centimeters, with the critical conditions of temperature, concentrations, and atmosphere. It turns out that the molecular weight of the insulating polymers plays an essential role in stable film growth and interfacial homogeneity at the phase separation boundary. Fabricating the transistor devices directly at the semiconductor-insulator boundaries, we demonstrate that the mixture of 3,11-didecyldinaphtho[2,3-d:2',3'-d']benzo[1,2-b:4,5-b']dithiophene and poly(methyl methacrylate) with the optimized weight-average molecular weight shows excellent device performances. The spontaneous phase separation with a one-step fabrication process leads to a high mobility up to 10 cm2 V-1 s-1 and a low subthreshold swing of 0.25 V dec-1 even without any surface treatment such as self-assembled monolayer modifications on oxide gate insulators.

  3. Electron transfer driven decomposition of adenine and selected analogs as probed by experimental and theoretical methods

    Science.gov (United States)

    Cunha, T.; Mendes, M.; Ferreira da Silva, F.; Eden, S.; García, G.; Bacchus-Montabonel, M.-C.; Limão-Vieira, P.

    2018-04-01

    We report on a combined experimental and theoretical study of electron-transfer-induced decomposition of adenine (Ad) and a selection of analog molecules in collisions with potassium (K) atoms. Time-of-flight negative ion mass spectra have been obtained in a wide collision energy range (6-68 eV in the centre-of-mass frame), providing a comprehensive investigation of the fragmentation patterns of purine (Pu), adenine (Ad), 9-methyl adenine (9-mAd), 6-dimethyl adenine (6-dimAd), and 2-D adenine (2-DAd). Following our recent communication about selective hydrogen loss from the transient negative ions (TNIs) produced in these collisions [T. Cunha et al., J. Chem. Phys. 148, 021101 (2018)], this work focuses on the production of smaller fragment anions. In the low-energy part of the present range, several dissociation channels that are accessible in free electron attachment experiments are absent from the present mass spectra, notably NH2 loss from adenine and 9-methyl adenine. This can be understood in terms of a relatively long transit time of the K+ cation in the vicinity of the TNI tending to enhance the likelihood of intramolecular electron transfer. In this case, the excess energy can be redistributed through the available degrees of freedom inhibiting fragmentation pathways. Ab initio theoretical calculations were performed for 9-methyl adenine (9-mAd) and adenine (Ad) in the presence of a potassium atom and provided a strong basis for the assignment of the lowest unoccupied molecular orbitals accessed in the collision process.

  4. Ab initio LCAO-MO cluster-type calculation of the self-consistent electronic screening charge density around a single hydrogen impurity in a nickel crystal

    International Nuclear Information System (INIS)

    Simpson, R.W.; Lane, N.F.; Chaney, R.C.

    1978-01-01

    The electronic structure for a Ni atom cluster embedded in bulk Ni by use of a spin-averaged local exchange SCF Ni crystal potential is calculated with an ab initio LCAO-Mo variational method. A single hydrogen impurity is added at the cluster center (fcc octahedral interstitial site) and the electronic structure computed iteratively until the change in electron density from the pure Ni cluster density is self-consistent. The H-Ni 6 self-consistent density change is compared to the charge density around a free hydrogen atom and to the initial-response density change in H-Ni 14 and H-Ni 38 clusters. 14 references

  5. First principles analysis of the CDW instability of single-layer 1T-TiSe2 and its evolution with charge carrier density

    Science.gov (United States)

    Guster, Bogdan; Canadell, Enric; Pruneda, Miguel; Ordejón, Pablo

    2018-04-01

    We present a density functional theory study of the electronic structure of single-layer TiSe2, and focus on the charge density wave (CDW) instability present on this 2D material. We explain the 2× 2 periodicity of the CDW from the phonon band structure of the undistorted crystal, which is unstable under one of the phonon modes at the M point. This can be understood in terms of a partial band gap opening at the Fermi level, which we describe on the basis of the symmetry of the involved crystal orbitals, leading to an energy gain upon the displacement of the atoms following the phonon mode in a 2  ×  1 structure. Furthermore, the combination of the corresponding phonons for the three inequivalent M points of the Brillouin zone leads to the 2  ×  2 distortion characteristic of the CDW state. This leads to a further opening of a full gap, which reduces the energy of the 2  ×  2 structure compared to the 2  ×  1 one of a single M point phonon, and makes the CDW structure the most stable one. We also analyze the effect of charge injection into the layer on the structural instability. We predict that the 2  ×  2 structure only survives for a certain range of doping levels, both for electrons and for holes, as doping reduces the energy gain due to the gap opening. We predict the transition from the commensurate 2  ×  2 distortion to an incommensurate one with increasing wavelength upon increasing the doping level, followed by the appearance of the undistorted 1  ×  1 structure for larger carrier concentrations.

  6. Can Kohn-Sham density functional theory predict accurate charge distributions for both single-reference and multi-reference molecules?

    Science.gov (United States)

    Verma, Pragya; Truhlar, Donald G

    2017-05-24

    Dipole moments are the first moment of electron density and are fundamental quantities that are often available from experiments. An exchange-correlation functional that leads to an accurate representation of the charge distribution of a molecule should accurately predict the dipole moments of the molecule. It is well known that Kohn-Sham density functional theory (DFT) is more accurate for the energetics of single-reference systems than for the energetics of multi-reference ones, but there has been less study of charge distributions. In this work, we benchmark 48 density functionals chosen with various combinations of ingredients, against accurate experimental data for dipole moments of 78 molecules, in particular 55 single-reference molecules and 23 multi-reference ones. We chose both organic and inorganic molecules, and within the category of inorganic molecules there are both main-group and transition-metal-containing molecules, with some of them being multi-reference. As one would expect, the multi-reference molecules are not as well described by single-reference DFT, and the functionals tested in this work do show larger mean unsigned errors (MUEs) for the 23 multi-reference molecules than the single-reference ones. Five of the 78 molecules have relatively large experimental error bars and were therefore not included in calculating the overall MUEs. For the 73 molecules not excluded, we find that three of the hybrid functionals, B97-1, PBE0, and TPSSh (each with less than or equal to 25% Hartree-Fock (HF) exchange), the range-separated hybrid functional, HSE06 (with HF exchange decreasing from 25% to 0 as interelectronic distance increases), and the hybrid functional, PW6B95 (with 28% HF exchange) are the best performing functionals with each yielding an MUE of 0.18 D. Perhaps the most significant finding of this study is that there exists great similarity among the success rate of various functionals in predicting dipole moments. In particular, of 39

  7. Nicotinamide adenine dinucleotide replenishment rescues colon degeneration in aged mice.

    Science.gov (United States)

    Zhu, Xudong; Shen, Weiyan; Wang, Ying; Jaiswal, Amit; Ju, Zhenyu; Sheng, Qinsong

    2017-01-01

    Susceptibility of gastrointestinal dysmotility increases with age-associated colonic degeneration. A paucity of remedies reversing colonic degeneration per se hinders the fundamental relief of symptoms. Here we discovered the correlation between colon degeneration and altered nicotinamide adenine dinucleotide (NAD) level in aged mice. Compared to 3-month-old young controls, 2-year-old mice showed a spectrum of degenerative colonic phenotypes and exhibited a significant elongated transit time and slowed stool frequency in the context of Lomotil-induced slow-transit constipation. Despite upregulated colonic tryptophan hydroxylases expression, serotonin release and expression of colon-predominant type IV serotonin receptor, reduced viability of interstitial cells of Cajal while enhanced aquaporins (Aqp1, 3 and 11) led to a less colonic motility and increased luminal dehydration in aged mice. Notably, this colonic degeneration was accompanied with reduced key NAD + -generating enzyme expression and lowered NAD + /NADH ratio in aged colon. Three-month continuous administration of beta nicotinamide mononucleotide, a NAD + precursor, elevated colonic NAD + level and improved defecation in aged mice. In contrast, pharmacological inhibition of nicotinamide phosphoribosyltransferase, the rate-limiting enzyme for NAD + biosynthesis, induced a reduction in colonic NAD content and impaired gastrointestinal function in young mice. Taken together, these findings suggest the beneficial effect of NAD + in maintaining colonic homoeostasis and reactivating NAD + biosynthesis may represent a promising strategy to counteract age-related gastrointestinal degeneration.

  8. DNA adenine methylation modulates pathogenicity of Klebsiella pneumoniae genotype K1

    Directory of Open Access Journals (Sweden)

    Chi-Tai Fang

    2017-08-01

    Conclusion: Our results support the view that DNA adenine methylation plays an important role in modulating the pathogenicity of K. pneumoniae genotype K1. The incomplete attenuation indicates the existence of other regulatory factors.

  9. Study of Single Event Effects induced by highly energetic charged particles of the space environment in CMOS image Sensors

    International Nuclear Information System (INIS)

    Lalucaa, Valerian

    2013-01-01

    This thesis studies the single event effects of space environment in CMOS image sensors (CIS). This work focuses on the effects of heavy ions on 3T standard photodiode pixels, and 4T and 5T pinned photodiode pixels. The first part describes the space radioactive environment and the sensor architecture. The most harmful events (SEL and SETs) are identified thanks to the scientific literature. The experimentally tested sensors agree with the theoretical work. SETs are compared to STARDUST simulations with a good agreement for all ions and sensors. The work explains why the SETs on 3T pixels are insensitive to the various photodiode designs, and they are decreased when an epitaxial substrate is used. A method using anti-blooming was successfully used in 4T and 5T pixels to prevent the spread of the SETs. The mechanism of latch-up in 4T pixel sensors is described. All the identified mechanisms are very useful to provide hardening methods for the CISs. (author) [fr

  10. Effect of adenine sulphate in the regeneration and elongation of common bean shoots

    OpenAIRE

    Lourdes R. García; Idalmis Bermúdez-Caraballoso; Novisel Veitía; Raúl Collado; Damaris Torres; Carlos Romero

    2012-01-01

    Plant regeneration and its further development of these are critical steps in tissue culture of Phaseolus vulgaris. The paper shows the effect of adenine sulfate included in the culture media on regeneration and elongation of shoots in the cultivar `CIAP 7247F'. The results showed that adenine sulfate affect plant regeneration and its elongation. The values of regenerated shoots and the plant height were increased. Keywords: in vitro culture, culture medium, Phaseolus vulgaris.

  11. Effect of adenine sulphate in the regeneration and elongation of common bean shoots

    Directory of Open Access Journals (Sweden)

    Lourdes R. García

    2012-01-01

    Full Text Available Plant regeneration and its further development of these are critical steps in tissue culture of Phaseolus vulgaris. The paper shows the effect of adenine sulfate included in the culture media on regeneration and elongation of shoots in the cultivar `CIAP 7247F'. The results showed that adenine sulfate affect plant regeneration and its elongation. The values of regenerated shoots and the plant height were increased. Keywords: in vitro culture, culture medium, Phaseolus vulgaris.

  12. REPRESSION BY ADENINE OF THE FORMYLTETRAHYDROFOLATE SYNTHETASE IN AN ANTIFOLIC-RESISTANT MUTANT OF STREPTOCOCCUS FAECALIS.

    Science.gov (United States)

    ALBRECHT, A M; HUTCHISON, D J

    1964-04-01

    Albrecht, Alberta M. (Sloan-Kettering Institute for Cancer Research, New York, N.Y.), and Dorris J. Hutchison. Repression by adenine of the formyltetrahydrofolate synthetase in an antifolic-resistant mutant of Streptococcus faecalis. J. Bacteriol. 87:792-798. 1964.-In an amethopterin-resistant mutant of Streptococcus faecalis ATCC 8043 under cultivation conditions requiring purine synthesis de novo, both the dihydrofolate reductase and the formyltetrahydrofolate synthetase were formed as constant fractions of the total protein synthesized during the exponential phase of growth. When excess adenine was added to the medium, the rate of formation of the synthetase was markedly decreased, i.e., repressed. Under these latter conditions, the synthesis of the reductase proceeded at a rate equal to that observed in the absence of adenine. The repressibility of the synthetase by adenine was demonstrated also by the decrease in rate of synthetase formation upon the addition of adenine to a culture actively synthesizing this enzyme. Guanine and hypoxanthine, like adenine, also repressed the synthetase; exogenous xanthine was less effective. Neither of the pyrimidines, thymine and uracil, at approximately 1 mug/ml, interfered with synthesis of the two enzymes.

  13. Labeling of mitochondrial adenine nucleotides of bovine sperm

    International Nuclear Information System (INIS)

    Cheetham, J.; Lardy, H.A.

    1986-01-01

    Incorporation of 32 P/sub i/ into the adenine nucleotide pool of intact bovine spermatozoa utilizing endogenous substrates results in a specific activity (S.A.) ratio ATP/ADP of 0.3 to 0.5, suggesting compartmentation of nucleotide pools or a pathway for phosphorylation of AMP in addition to the myokinase reaction. Incubation of filipin-permeabilized cells with pyruvate, acetylcarnitine, or α-ketoglutarate (αKG) resulted in ATP-ADP S.A. ratios of 0.5, 0.8, and 1.6, respectively, for mitochondrial nucleotides. However, when malate was included with pyruvate or acetylcarnitine, the ATP/ADP S.A. ratio increased by 400% to 2.0 for pyruvate/malate and by 290% to 2.8 for acetylcarnitine/malate, while the ATP/ADP ratio increased by less than 100% in both cases. These results may indicate that under conditions of limited flux through the citric acid cycle a pathway for phosphorylation of AMP from a precursor other than ATP exists or that ATP is compartmented within the mitochondrion. In the presence of uncoupler and oligomycin with αKG, pyruvate/malate, or acetylcarnitine/malate, 32 P/sub i/ is incorporated primarily into ATP, resulting in an ATP/ADP S.A. ratio of 4.0 for αKG, 2.7 for pyruvate/malate, and 2.8 for acetylcarnitine/malate. These data are consistent with phosphorylation of ADP during substrate level phosphorylation in the citric acid cycle

  14. A novel approach to adenine-induced chronic kidney disease associated anemia in rodents.

    Directory of Open Access Journals (Sweden)

    Asadur Rahman

    Full Text Available To date, good experimental animal models of renal anemia are not available. Therefore, the purpose of this study was to establish a novel approach to induce chronic kidney disease (CKD with severe anemia by oral administration of adenine in rodents. Adenine was administered to 6-week-old male C57BL/6 mice (25 and 50 mg/kg body weight by oral gavage daily for 28 days. Serum creatinine and BUN as well as hematocrit, hemoglobin (Hb and plasma erythropoietin (EPO levels were monitored to assess renal function and anemia, respectively. Adenine at 25 mg/kg for 28 days slightly increased plasma creatinine levels, but did not induce anemia. In contrast, 50 mg/kg of adenine daily for 28 days showed severe renal dysfunction (plasma creatinine 1.9 ± 0.10 mg/dL and anemia (hematocrit 36.5 ± 1.0% and EPO 28 ± 2.4 pg/mL as compared with vehicle-treated mice (0.4 ± 0.02 mg/dL, 49.6 ± 1.6% and 61 ± 4.0 pg/mL, respectively. At the end of experiment, level of Hb also significantly reduced in 50 mg/kg adenine administration group. Remarkable histological changes of kidney tissues characterized by interstitial fibrosis and cystic appearance in tubules were observed in 50 mg/kg of adenine treatment group. These results have demonstrated that oral dosing with adenine at 50 mg/kg for 28 days is suitable to induce a stable anemia associated with CKD in mice.

  15. A novel approach to adenine-induced chronic kidney disease associated anemia in rodents.

    Science.gov (United States)

    Rahman, Asadur; Yamazaki, Daisuke; Sufiun, Abu; Kitada, Kento; Hitomi, Hirofumi; Nakano, Daisuke; Nishiyama, Akira

    2018-01-01

    To date, good experimental animal models of renal anemia are not available. Therefore, the purpose of this study was to establish a novel approach to induce chronic kidney disease (CKD) with severe anemia by oral administration of adenine in rodents. Adenine was administered to 6-week-old male C57BL/6 mice (25 and 50 mg/kg body weight) by oral gavage daily for 28 days. Serum creatinine and BUN as well as hematocrit, hemoglobin (Hb) and plasma erythropoietin (EPO) levels were monitored to assess renal function and anemia, respectively. Adenine at 25 mg/kg for 28 days slightly increased plasma creatinine levels, but did not induce anemia. In contrast, 50 mg/kg of adenine daily for 28 days showed severe renal dysfunction (plasma creatinine 1.9 ± 0.10 mg/dL) and anemia (hematocrit 36.5 ± 1.0% and EPO 28 ± 2.4 pg/mL) as compared with vehicle-treated mice (0.4 ± 0.02 mg/dL, 49.6 ± 1.6% and 61 ± 4.0 pg/mL, respectively). At the end of experiment, level of Hb also significantly reduced in 50 mg/kg adenine administration group. Remarkable histological changes of kidney tissues characterized by interstitial fibrosis and cystic appearance in tubules were observed in 50 mg/kg of adenine treatment group. These results have demonstrated that oral dosing with adenine at 50 mg/kg for 28 days is suitable to induce a stable anemia associated with CKD in mice.

  16. Glibenclamide improves kidney and heart structure and function in the adenine-diet model of chronic kidney disease.

    Science.gov (United States)

    Diwan, Vishal; Gobe, Glenda; Brown, Lindsay

    2014-01-01

    The development of chronic kidney disease (CKD) and associated cardiovascular disease involves free radical damage and inflammation. Addition of adenine to the diet induces inflammation followed by CKD and cardiovascular disease. NOD-like receptor protein-3 (NLRP-3) is pro-inflammatory in the kidney; glibenclamide inhibits production of NLRP-3. Male Wistar rats were fed either control rat food or adenine (0.25%) in this food for 16 weeks. Glibenclamide (10 mg/kg/day) was administered to two groups with and without adenine for the final 8 weeks. Kidney function (blood urea nitrogen/BUN, plasma creatinine/PCr, plasma uric acid, proteinuria), kidney structure (fibrosis, inflammation), cardiovascular parameters (blood pressure, left ventricular stiffness, vascular responses and echocardiography) and protein expression of markers for oxidative stress (HO-1), and inflammation (TNF-α, NLRP-3) were assessed. In adenine-fed rats, glibenclamide decreased BUN (controls: 6±0.6; adenine: 56.6±5.4; adenine+glibenclamide: 19.4±2.7 mmol/L), PCr (controls: 42±2.8; adenine: 268±23; adenine+glibenclamide: 81±10 μmol/L), proteinuria (controls: 150±7.4; adenine: 303±19; adenine+glibenclamide: 220±13 μmol/L) (all pchronic inflammatory cells, fibrosis, tubular damage and expression of HO-1, TNF-α and NLRP-3 in the kidney. Glibenclamide did not alter plasma uric acid concentrations (controls: 38±1; adenine: 63±4; adenine+glibenclamide: 69±14 μmol/L). Cardiovascular changes included decreased systolic blood pressure and improved vascular responses although cardiac fibrosis, left ventricular stiffness and hypertrophy were not reduced. Glibenclamide improved kidney structure and function in CKD and decreased some cardiovascular parameters. Inflammatory markers and cell populations were attenuated by glibenclamide in kidneys. Copyright © 2013 Elsevier Ltd. All rights reserved.

  17. Charge trapping and storage by composite P3HT/PC60BM nanoparticles investigated by fluorescence-voltage/single particle spectroscopy.

    Science.gov (United States)

    Hu, Zhongjian; Gesquiere, Andre J

    2011-12-28

    Fluorescence-voltage/single particle spectroscopy (F-V/SPS) was employed to study exciton-hole polaron interactions and interfacial charge transfer processes for pure poly(3-hexylthiophene) (P3HT) nanoparticles (NPs) and composite P3HT/PC(60)BM NPs in functioning hole-injection devices. F-V/SPS data collected on a particle-by-particle basis reveal an apparent bistability in the fluorescence-voltage modulation curves for composite NPs of P3HT and [6,6]-phenyl-C(61)-butyric acid methyl ester (PC(60)BM) that is absent for pure P3HT NPs. A pronounced deep trapping of free electrons photogenerated from the composite P3HT/PC(60)BM NPs at the NP/dielectric interface and hole trapping by fullerene anions in composite P3HT/PC(60)BM NPs under photoexcitation lies at the basis of this finding. The deep electron trapping effect reported here for composite conjugated polymer/fullerene NPs presents an opportunity for future application of these NPs in nanoscale memory and imaging devices. © 2011 American Chemical Society

  18. Twisted intramolecular charge transfer investigation of semi organic L-Glutamic acid hydrochloride single crystal for organic light-emitting and optical limiting applications

    Science.gov (United States)

    Joy, Lija K.; George, Merin; Alex, Javeesh; Aravind, Arun; Sajan, D.; Vinitha, G.

    2018-03-01

    Single crystals of L-Glutamic acid hydrochloride (LGHCl) were grown by slow evaporation solution technique and good crystalline perfection was confirmed by Powder X-ray diffraction studies. The complete vibrational studies of the compound were analyzed by FT-IR, FT-Raman and UV-visible spectra combined with Normal Coordinate Analysis (NCA) following the scaled quantum mechanical force field methodology and density functional theory (DFT). Twisted Intramolecular Charge Transfer (ICT) occurs due to the presence of strong ionic intra-molecular Nsbnd H⋯O hydrogen bonding was confirmed by Hirshfeld Surface analysis. The existence of intermolecular Nsbnd H⋯Cl hydrogen bonds due to the interaction between the lone pair of oxygen with the antibonding orbital was established by NBO analysis. The Z-scan result indicated that the title molecule exhibits saturable absorption behavior. The attractive third-order nonlinear properties suggest that LGHCl can be a promising candidate for the design and development devices for optical limiting applications. LGHCL exhibits distinct emission in the blue region of the fluorescence lifetime which proves to be a potential candidate for blue- Organic light-emitting diodes (OLEDs) fabrication.

  19. Determination of adenine based on the fluorescence recovery of the L-Tryptophan-Cu2+ complex

    Science.gov (United States)

    Duan, Ruilin; Li, Chunyan; Liu, Shaopu; Liu, Zhongfang; Li, Yuanfang; Yuan, Yusheng; Hu, Xiaoli

    2016-01-01

    A simple and sensitive method for determination of adenine was developed based on fluorescence quenching and recovery of L-Tryptophan (L-Trp). The fluorescence of L-Trp could efficiently quenched by copper ion compared with other common metal ions. Upon addition of adenine (Ade) in L-Trp-Cu(II) system, the fluorescence was reoccurred. Under the optimum conditions, the recovery fluorescence intensity was linearly correlated with the concentration of adenine in the range from 0.34 to 25.0 μmol L-1, with a correlation coefficient (R2) of 0.9994. The detection limit (3σ/k) was 0.046 μmol L-1, indicating that this method could applied to detect trace adenine. In this study, amino acids including L-Trp, D-Trp, L-Tyr, D-Tyr, L-Phe, D-Phe were investigated and only L-Trp could well chelated copper ion. Additionally, the mechanism of quench and recovery also were discussed and the method was successfully applied to detect the adenine in DNA with satisfactory results.

  20. Quercetin Attenuates Vascular Calcification through Suppressed Oxidative Stress in Adenine-Induced Chronic Renal Failure Rats

    Directory of Open Access Journals (Sweden)

    Xue-ying Chang

    2017-01-01

    Full Text Available Background. This study investigated whether quercetin could alleviate vascular calcification in experimental chronic renal failure rats induced by adenine. Methods. 32 adult male Wistar rats were randomly divided into 4 groups fed normal diet, normal diet with quercetin supplementation (25 mg/kg·BW/d, 0.75% adenine diet, or adenine diet with quercetin supplementation. All rats were sacrificed after 6 weeks of intervention. Serum renal functions biomarkers and oxidative stress biomarkers were measured and status of vascular calcification in aorta was assessed. Furthermore, the induced nitric oxide synthase (iNOS/p38 mitogen activated protein kinase (p38MAPK pathway was determined to explore the potential mechanism. Results. Adenine successfully induced renal failure and vascular calcification in rat model. Quercetin supplementation reversed unfavorable changes of phosphorous, uric acid (UA and creatinine levels, malonaldehyde (MDA content, and superoxide dismutase (SOD activity in serum and the increases of calcium and alkaline phosphatase (ALP activity in the aorta (P<0.05 and attenuated calcification and calcium accumulation in the medial layer of vasculature in histopathology. Western blot analysis showed that iNOS/p38MAPK pathway was normalized by the quercetin supplementation. Conclusions. Quercetin exerted a protective effect on vascular calcification in adenine-induced chronic renal failure rats, possibly through the modulation of oxidative stress and iNOs/p38MAPK pathway.

  1. 139La NMR investigation of the charge and spin order in a La1.885Sr0.115CuO4 single crystal

    Science.gov (United States)

    Arsenault, A.; Takahashi, S. K.; Imai, T.; He, W.; Lee, Y. S.; Fujita, M.

    2018-02-01

    139La NMR is suited for investigations into magnetic properties of La2CuO4 -based cuprates in the vicinity of their magnetic instabilities, owing to the modest hyperfine interactions between 139La nuclear spins and Cu electron spins. We report comprehensive 139La NMR measurements on a single-crystal sample of high-Tc superconductor La1.885Sr0.115CuO4 in a broad temperature range across the charge and spin order transitions (Tcharge≃80 K, Tspinneutron≃Tc=30 K). From the high-precision measurements of the linewidth for the nuclear spin Iz=+1 /2 to -1 /2 central transition, we show that paramagnetic line broadening sets in precisely at Tcharge due to enhanced spin correlations within the CuO2 planes. Additional paramagnetic line broadening ensues below ˜35 K, signaling that Cu spins in some segments of CuO2 planes are on the verge of three-dimensional magnetic order. A static hyperfine magnetic field arising from ordered Cu moments along the a b plane, however, begins to develop only below Tspinμ S R=15 -20 K, where earlier muon spin rotation measurements detected Larmor precession for a small volume fraction (˜20 % ) of the sample. Based on the measurement of 139La nuclear-spin-lattice relaxation rate 1 /T1 , we also show that charge order triggers enhancement of low-frequency Cu spin fluctuations inhomogeneously; a growing fraction of 139La sites is affected by enhanced low-frequency spin fluctuations toward the eventual magnetic order, whereas a diminishing fraction continues to exhibit a behavior analogous to the optimally superconducting phase even below Tcharge. These 139La NMR results corroborate our recent 63Cu NMR observation that a very broad, anomalous winglike signal gradually emerges below Tcharge, whereas the normally behaving, narrower main peak is gradually wiped out [T. Imai et al., Phys. Rev. B 96, 224508 (2017), 10.1103/PhysRevB.96.224508]. Furthermore, we show that the enhancement of low-energy spin excitations in the low-temperature regime

  2. Cleavage of nicotinamide adenine dinucleotide by the ribosome-inactivating protein from Momordica charantia.

    Science.gov (United States)

    Vinkovic, M; Dunn, G; Wood, G E; Husain, J; Wood, S P; Gill, R

    2015-09-01

    The interaction of momordin, a type 1 ribosome-inactivating protein from Momordica charantia, with NADP(+) and NADPH has been investigated by X-ray diffraction analysis of complexes generated by co-crystallization and crystal soaking. It is known that the proteins of this family readily cleave the adenine-ribose bond of adenosine and related nucleotides in the crystal, leaving the product, adenine, bound to the enzyme active site. Surprisingly, the nicotinamide-ribose bond of oxidized NADP(+) is cleaved, leaving nicotinamide bound in the active site in the same position but in a slightly different orientation to that of the five-membered ring of adenine. No binding or cleavage of NADPH was observed at pH 7.4 in these experiments. These observations are in accord with current views of the enzyme mechanism and may contribute to ongoing searches for effective inhibitors.

  3. Tomenphantadenine, an unprecedented germacranolide-adenine hybrid heterodimer from the medicinal plant Elephantopus tomentosus L.

    Science.gov (United States)

    Guo, Zhi Kai; Wang, Bei; Cai, Cai Hong; Huang, Sheng Zhuo; Yuan, Jing Zhe; Mei, Wen Li; Dai, Hao Fu

    2018-03-01

    An unusual adenine-substituted germacrane sesquiterpene lactone, tomenphantadenine (1), has been isolated from the whole plant of Elephantopus tomentosus L. The structure of this compound was established by comprehensive spectroscopic analysis including high resolution (HR) ESI-MS, 1D and 2D nuclear magnetic resonance (NMR) spectroscopic data. This compound features novel hybrid pattern of germacrane sesquiterpene with adenine through C-N linkage, and a possible biosynthetic pathway for it was proposed. Compound 1 showed potent antibacterial activity against the gram-positive Staphylococcus aureus and weak acetylcholinesterase (AChE) inhibitory activity. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. A Charge Parity Ammeter

    Science.gov (United States)

    Lambert, Nicholas J.; Edwards, Megan; Ciccarelli, Chiara; Ferguson, Andrew J.

    2014-03-01

    A metallic double-dot is measured with radio frequency reflectometry. Changes in the total electron number of the double-dot are determined via single electron tunnelling contributions to the complex electrical impedance. Electron counting experiments are performed by monitoring the impedance, demonstrating operation of a single electron ammeter without the need for external charge detection.

  5. Changes in phosphorylation of adenosine phosphate and redox state of nicotinamide-adenine dinucleotide (phosphate) in Geobacter sulfurreducens in response to electron acceptor and anode potential variation

    KAUST Repository

    Rose, Nicholas D.

    2015-12-01

    © 2015 Elsevier B.V. Geobacter sulfurreducens is one of the dominant bacterial species found in biofilms growing on anodes in bioelectrochemical systems. The intracellular concentrations of reduced and oxidized forms of nicotinamide-adenine dinucleotide (NADH and NAD+, respectively) and nicotinamide-adenine dinucleotide phosphate (NADPH and NADP+, respectively) as well as adenosine triphosphate (ATP), adenosine diphosphate (ADP), and adenosine monophosphate (AMP) were measured in G. sulfurreducens using fumarate, Fe(III)-citrate, or anodes poised at different potentials (110, 10, -90, and -190mV (vs. SHE)) as the electron acceptor. The ratios of CNADH/CNAD+ (0.088±0.022) and CNADPH/CNADP+ (0.268±0.098) were similar under all anode potentials tested and with Fe(III)-citrate (reduced extracellularly). Both ratios significantly increased with fumarate as the electron acceptor (0.331±0.094 for NAD and 1.96±0.37 for NADP). The adenylate energy charge (the fraction of phosphorylation in intracellular adenosine phosphates) was maintained near 0.47 under almost all conditions. Anode-growing biofilms demonstrated a significantly higher molar ratio of ATP/ADP relative to suspended cultures grown on fumarate or Fe(III)-citrate. These results provide evidence that the cellular location of reduction and not the redox potential of the electron acceptor controls the intracellular redox potential in G. sulfurreducens and that biofilm growth alters adenylate phosphorylation.

  6. Fractional charges

    International Nuclear Information System (INIS)

    Saminadayar, L.

    2001-01-01

    20 years ago fractional charges were imagined to explain values of conductivity in some materials. Recent experiments have proved the existence of charges whose value is the third of the electron charge. This article presents the experimental facts that have led theorists to predict the existence of fractional charges from the motion of quasi-particles in a linear chain of poly-acetylene to the quantum Hall effect. According to the latest theories, fractional charges are neither bosons nor fermions but anyons, they are submitted to an exclusive principle that is less stringent than that for fermions. (A.C.)

  7. Synthetic models related to DNA-intercalating molecules. Interactions between 8-alkoxypsoralen and adenine

    International Nuclear Information System (INIS)

    Decout, J.L.; Lhomme, J.

    1983-01-01

    To investigate the interactions and the photoreactions between furocoumarins and adenine, compounds in which a psoralen molecule is linked by different polymethylene bridges have been synthesised. Ring-ring intramolecular interactions are observed by UV spectroscopy. Thermodynamic parameters of these hydrophobic interactions are determined by the study of the variation of the hypochromic effect with temperature. (author)

  8. Loss of Hoogsteen Pairing Ability upon N1 Adenine Platinum Binding

    Czech Academy of Sciences Publication Activity Database

    Schmidt, K. S.; Reedijk, J.; Weisz, K.; Janke, E. M. B.; Šponer, Judit E.; Šponer, Jiří; Lippert, B.

    2002-01-01

    Roč. 41, č. 11 (2002), s. 2855-2863 ISSN 0020-1669 R&D Projects: GA MŠk LN00A016; GA AV ČR IAA4040903 Institutional research plan: CEZ:AV0Z4040901 Keywords : adenine * thymine * Hoogsteen pairing ability Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.950, year: 2002

  9. The effect of caffeine and adenine on radiation induced suppression of DNA synthesis, and cell survival

    International Nuclear Information System (INIS)

    Wilcoxson, L.T.; Griffiths, T.D.

    1984-01-01

    Exposure of cultured mammalian cells to ionizing radiation or UV light results in a transient decrease in the rate of DNA synthesis. This depression in synthetic rate may be attenuated or deferred via a post-irradiation treatment with caffeine or adenine. It has been suggested that this attenuation may increase the fixation of damage and, therefore, increase radiation sensitivity. However, it has been previously reported that, for V79 cells treated with caffeine or adenine, no correlation exists between the extent of depression and cell survival. The present investigation expands upon these findings by examining the effect of caffeine or adenine post-irradiation treatment on two cell lines with normal UV sensitivity, mouse 3T3 and CHO AA8 cells, and one UV sensitive cell line, CHO UV5 cells. Both caffeine and adenine have been found to reduce, or delay, the suppression in DNA synthesis in all three cell lines. Surprisingly, caffeine appeared to induced even the UV5 cells to recover DNA synthetic ability. The amount of reduction in suppression of DNA synthesis, however, varies between the different cell lines and no consistent relationship with cell survival has emerged

  10. SERS, XPS, and DFT Study of Adenine Adsorption on Silver and Gold Surfaces.

    Science.gov (United States)

    Pagliai, Marco; Caporali, Stefano; Muniz-Miranda, Maurizio; Pratesi, Giovanni; Schettino, Vincenzo

    2012-01-19

    The adsorption of adenine on silver and gold surfaces has been investigated combining density functional theory calculations with surface-enhanced Raman scattering and angle-resolved X-ray photoelectron spectroscopy measurements, obtaining useful insight into the orientation and interaction of the nucleobase with the metal surfaces.

  11. Relation between energy production and adenine nucleotide metabolism in human blood platelets

    NARCIS (Netherlands)

    Akkerman, Jan Willem N.; Gorter, G.

    1980-01-01

    The relation between ATP production and adenine nucleotide metabolism was investigated in human platelets which were starved by incubation in glucose-free, CN−-containing medium and subsequently incubated with different amounts of glucose. In the absence of mitochondrial energy production (blocked

  12. Prevention of injury by resveratrol in a rat model of adenine-induced ...

    African Journals Online (AJOL)

    1Department of Nephrology, Heping Hospital Affiliated to Changzhi Medical College, Changzhi, Shanxi 046000, 2Clinical. Medicine ... tubule swelling and expansion induced by adenine administration. Conclusion: ... administration in a rat model of CKD by inhibiting FGF-23, parathyroid hormone, and phosphate. Thus,.

  13. Kinetic analysis of Yersinia pestis DNA adenine methyltransferase activity using a hemimethylated molecular break light oligonucleotide.

    Directory of Open Access Journals (Sweden)

    Robert J Wood

    Full Text Available BACKGROUND: DNA adenine methylation plays an important role in several critical bacterial processes including mismatch repair, the timing of DNA replication and the transcriptional control of gene expression. The dependence of bacterial virulence on DNA adenine methyltransferase (Dam has led to the proposal that selective Dam inhibitors might function as broad spectrum antibiotics. METHODOLOGY/PRINCIPAL FINDINGS: Herein we report the expression and purification of Yersinia pestis Dam and the development of a continuous fluorescence based assay for DNA adenine methyltransferase activity that is suitable for determining the kinetic parameters of the enzyme and for high throughput screening against potential Dam inhibitors. The assay utilised a hemimethylated break light oligonucleotide substrate containing a GATC methylation site. When this substrate was fully methylated by Dam, it became a substrate for the restriction enzyme DpnI, resulting in separation of fluorophore (fluorescein and quencher (dabcyl and therefore an increase in fluorescence. The assays were monitored in real time using a fluorescence microplate reader in 96 well format and were used for the kinetic characterisation of Yersinia pestis Dam, its substrates and the known Dam inhibitor, S-adenosylhomocysteine. The assay has been validated for high throughput screening, giving a Z-factor of 0.71+/-0.07 indicating that it is a sensitive assay for the identification of inhibitors. CONCLUSIONS/SIGNIFICANCE: The assay is therefore suitable for high throughput screening for inhibitors of DNA adenine methyltransferases and the kinetic characterisation of the inhibition.

  14. Severe hyperparathyroidism with bone abnormalities and metastatic calcification in rats with adenine-induced uraemia.

    Science.gov (United States)

    Tamagaki, Keiichi; Yuan, Qunsheng; Ohkawa, Hiroyuki; Imazeki, Ikuo; Moriguchi, Yoshiyuki; Imai, Nobuo; Sasaki, Susumu; Takeda, Kazuo; Fukagawa, Masafumi

    2006-03-01

    Marked parathyroid hyperplasia with bone diseases and vascular calcification are unsolved issues in dialysis patients. In this study, we made azotemic model rats by adenine feeding and analyzed the development and progression of the abnormalities. Renal failure was induced in 8-week-old male Wistar rats by feeding 0.75% adenine-containing diet for 6 weeks. Serum parameters, parathyroid hyperplasia, bone changes and metastatic calcification were examined at 2, 4 and 6 weeks. Progressive increase of serum creatinine and inorganic phosphate, and decreased levels of serum calcium and 1,25(OH)2D3 were confirmed. Markedly enlarged parathyroid glands and extremely high PTH levels were observed in all adenine-fed rats compared with the control (PTH: 199.3+/-58.0 vs 10.5+/-3.0 pmol/l, Prats. Uraemic rats made by adenine diet developed severe abnormalities of calcium metabolism in a relatively short period and therefore they may serve as a useful model for the analysis of parathyroid hyperplasia and vascular calcification in chronic renal failure.

  15. Circular dichroism spectroscopy of conformers of (guanine + adenine) repeat strands of DNA

    Czech Academy of Sciences Publication Activity Database

    Kejnovská, Iva; Kypr, Jaroslav; Vorlíčková, Michaela

    2003-01-01

    Roč. 15, č. 7 (2003), s. 584-592 ISSN 0899-0042 R&D Projects: GA AV ČR IAA4004201; GA ČR GA204/01/0561 Institutional research plan: CEZ:AV0Z5004920 Keywords : DNA conformation * (guanine + adenine) repeats * homoduplexes Subject RIV: BO - Biophysics Impact factor: 1.793, year: 2003

  16. Renoprotective effect of Chinese chive polysaccharides in adenine-induced chronic renal failure.

    Science.gov (United States)

    Li, Qiang-Ming; Chena, Hao-Ran; Zha, Xue-Qiang; Lu, Chao-Qun; Pan, Li-Hua; Luo, Jian-Ping

    2018-01-01

    In this work, we investigated the effect of Chinese chive polysaccharides (CCP) on renal function in mice with adenine-induced chronic renal failure (CRF). Results exhibited that adenine treatment caused serious renal pathological damages and elevation of serum creatinine and blood urea nitrogen of mice. However, these changes could be significantly reversed by the administration of CCP in a dose-dependent manner. When CCP dosage reached 200mg/kg/day, the area of renal pathological damage was decreased by 59.2%, and the levels of serum creatinine and blood urea nitrogen were decreased by 23.9% and 34.7% compared to those of model group. Moreover, it was found that renal oxidative damage, inflammation and fibrosis of adenine-induced CRF mice could also be significantly inhibited by CCP. These results suggested that CCP could improve the kidney functions of adenine-induced CRF mice and the renoprotective effect might be associated with its antioxidant, anti-inflammatory and anti-fibrosis activities. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Photochemical Reaction Between 1,2-Naphthoquinone and Adenine in Binary Water-Acetonitrile Solutions.

    Science.gov (United States)

    Zhou, Qiaohui; Wei, Yaxiong; Liu, Xiang; Chen, Lin; Zhou, Xiaoguo; Liu, Shilin

    2018-01-01

    The photochemical reaction between 1,2-naphthoquinone (NQ) and adenine was investigated using nanosecond time-resolved laser flash photolysis. With photolysis at 355 nm, the lowest triplet state T 1 of NQ was produced via intersystem crossing from its singlet excited state. The triplet-triplet absorption of the state contributes three bands of transient spectra at 374, 596 and 650 nm, respectively, in pure acetonitrile and binary water-acetonitrile solutions. In the presence of adenine, the observation of A· + (at 363 nm) and NQ+H· radical (at 343 and 485 nm) indicates a multistep mechanism of electron transfer process followed by a proton transfer between 3 NQ* and adenine. By fitting with the Stern-Volmer relationship, the quenching rate constant k q of 3 NQ* by adenine in binary water-acetonitrile solutions (4/1, volume ratio, v/v) is determined as 1.66 × 10 9  m -1  s -1 . Additionally, no spectral evidence confirms the existence of electron transfer between 3 NQ* with thymine, cytosine and uracil. © 2017 The American Society of Photobiology.

  18. Effect of adenine nucleotides and gamma radiation on the transport of TEMPOL across the erythrocyte membrane

    Energy Technology Data Exchange (ETDEWEB)

    Jozwiak, Z.; Gwozdzinski, K.; Helszer, Z. (Lodz Univ. (Poland). Dept. of Biophysics)

    1983-09-01

    External adenine compounds bring about changes in the transport of hydrophilic molecules across control and irradiated bovine erythrocyte membranes. Changes in the transport induced by incubation of erythrocytes with nucleotides depend on the type of nucleotide and its concentration. The range of nucleotide concentrations over which the stimulatory effect on the transport occurs is established.

  19. Prevention of injury by resveratrol in a rat model of adenine-induced ...

    African Journals Online (AJOL)

    Purpose: To investigate the preventive effect of resveratrol against renal pathological changes in a rat model of chronic kidney disease (CKD). Methods: CKD was induced by daily intragastric administration of adenine (200 mg/kg) for 1 month. The effect of 10, 15, and 20 mg/kg doses of resveratrol on the levels of ...

  20. The effect of activated charcoal on adenine-induced chronic renal failure in rats.

    Science.gov (United States)

    Ali, Badreldin H; Alza'abi, Mohamed; Ramkumar, Aishwarya; Al-Lawati, Intisar; Waly, Mostafa I; Beegam, Sumaya; Nemmar, Abderrahim; Brand, Susanne; Schupp, Nicole

    2014-03-01

    Activated charcoal (AC) is a sorbent that has been shown to remove urinary toxins like urea and indoxyl sulfate. Here, the influence of AC on kidney function of rats with experimental chronic renal failure (CRF) is investigated. CRF was induced in rats by feeding adenine (0.75%) for four weeks. As an intervention, AC was added to the feed at concentrations of 10%, 15% or 20%. Adenine treatment impaired kidney function: it lowered creatinine clearance and increased plasma concentrations of creatinine, urea, neutrophil gelatinase-associated lipocalin and vanin-1. Furthermore, it raised plasma concentrations of the uremic toxins indoxyl sulfate, phosphate and uric acid. Renal morphology was severely damaged and histopathological markers of inflammation and fibrosis were especially increased. In renal homogenates, antioxidant indices, including superoxide dismutase and catalase activity, total antioxidant capacity and reduced glutathione were adversely affected. Most of these changes were significantly ameliorated by dietary administration of AC at a concentration of 20%, while effects induced by lower doses of dietary AC on adenine nephrotoxicity were not statistically significant. The results suggest that charcoal is a useful sorbent agent in dietary adenine-induced CRF in rats and that its usability as a nephroprotective agent in human kidney disease should be studied. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Probing electronic coupling between adenine bases in RNA strands from synchrotron radiation circular dichroism experiments

    DEFF Research Database (Denmark)

    Nielsen, Lisbeth Munksgård; Hoffmann, Søren Vrønning; Nielsen, Steen Brøndsted

    2012-01-01

    Circular dichroism spectra (176–330 nm) of RNA adenine oligomers, (rA)n (n = 1–10, 12, 15, and 20), reveal electronic coupling between two bases in short strands. The number of interacting bases in long strands is more and larger than that reported previously for the corresponding DNA strands....

  2. Effect of AST-120 on Endothelial Dysfunction in Adenine-Induced Uremic Rats

    Directory of Open Access Journals (Sweden)

    Yuko Inami

    2014-01-01

    Full Text Available Aim. Chronic kidney disease (CKD represents endothelial dysfunction. Monocyte adhesion is recognized as the initial step of arteriosclerosis. Indoxyl sulfate (IS is considered to be a risk factor for arteriosclerosis in CKD. Oral adsorbent AST-120 retards deterioration of renal function, reducing accumulation of IS. In the present study, we determined the monocyte adhesion in the adenine-induced uremic rats in vivo and effects of AST-120 on the adhesion molecules. Methods. Twenty-four rats were divided into control, control+AST-120, adenine, and adenine+AST-120 groups. The number of monocytes adherent to the endothelium of thoracic aorta by imaging the entire endothelial surface and the mRNA expressions of adhesion and atherosclerosis-related molecules were examined on day 49. The mRNA expressions of ICAM-1 and VCAM-1 in human umbilical vein endothelial cells were also examined. Results. Adenine increased the number of adherent monocytes, and AST-120 suppressed the increase. The monocyte adhesion was related to serum creatinine and IS in sera. Overexpression of VCAM-1 and TGF-β1 mRNA in the arterial walls was observed in uremic rats. IS induced increase of the ICAM-1 and VCAM-1 mRNA expressions in vitro. Conclusion. It appears that uremic condition introduces the monocyte adhesion to arterial wall and AST-120 might inhibit increasing of the monocyte adherence with CKD progression.

  3. A new method for charge trapping measurement during electron beam irradiation: application to glass containing alkali ions and single-crystalline quartz

    International Nuclear Information System (INIS)

    Fakhfakh, S; Ghorbel, N; Jbara, O; Rondot, S; Martin, D; Fakhfakh, Z; Kallel, A

    2004-01-01

    The aim of this work is to study the electron irradiation behaviour of an insulating material surface using a scanning electron microscope (SEM). The charging phenomena caused in two kinds of insulating materials (quartz and glass) by continuous electron irradiation have been observed. The discharging phenomena following switching off of irradiation have also been studied. The trapped charge density is determined by using the so-called electrostatic influence method based on the measurement, during and after the irradiation, of the influence and leakage currents using an arrangement adapted to the SEM. The experimental results reveal that the behaviour under irradiation of glass is entirely different from that of quartz. The trapped charges are found to be different, and the dependence of charging on the primary beam energy is discussed. The charging and discharging time constants have been determined accurately, and their evolution versus the mean electron penetration depth is qualitatively explained. Moreover, the role of secondary electron emission in the regulation mechanism of charging is underlined

  4. A new method for charge trapping measurement during electron beam irradiation: application to glass containing alkali ions and single-crystalline quartz

    Energy Technology Data Exchange (ETDEWEB)

    Fakhfakh, S [LASSI/DTI UMR CNRS 6107, Faculte des Sciences BP 1039, 51687 Reims CDX 2 (France); Ghorbel, N [LASSI/DTI UMR CNRS 6107, Faculte des Sciences BP 1039, 51687 Reims CDX 2 (France); Jbara, O [LASSI/DTI UMR CNRS 6107, Faculte des Sciences BP 1039, 51687 Reims CDX 2 (France); Rondot, S [LASSI/DTI UMR CNRS 6107, Faculte des Sciences BP 1039, 51687 Reims CDX 2 (France); Martin, D [Saint Gobain Recherche, 39 quai Lucien Lefranc, BP 135, 93303 Aubervilliers CDX (France); Fakhfakh, Z [LaMaCop, Faculte des Sciences de SFAX, Route Soukra km 3, BP 802, 3018 Sfax (Tunisia); Kallel, A [LaMaCop, Faculte des Sciences de SFAX, Route Soukra km 3, BP 802, 3018 Sfax (Tunisia)

    2004-08-07

    The aim of this work is to study the electron irradiation behaviour of an insulating material surface using a scanning electron microscope (SEM). The charging phenomena caused in two kinds of insulating materials (quartz and glass) by continuous electron irradiation have been observed. The discharging phenomena following switching off of irradiation have also been studied. The trapped charge density is determined by using the so-called electrostatic influence method based on the measurement, during and after the irradiation, of the influence and leakage currents using an arrangement adapted to the SEM. The experimental results reveal that the behaviour under irradiation of glass is entirely different from that of quartz. The trapped charges are found to be different, and the dependence of charging on the primary beam energy is discussed. The charging and discharging time constants have been determined accurately, and their evolution versus the mean electron penetration depth is qualitatively explained. Moreover, the role of secondary electron emission in the regulation mechanism of charging is underlined.

  5. Photoelectron Spectroscopy of Singly and Doubly Charged Higher Fullerenes at Low Temperatures: C76-, C78-, C84- and C76(2-), C78(2-), C84(2-)

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xue B.; Woo, Hin-koon; Yang, Jie; Kappes, Manfred M.; Wang, Lai S.

    2007-12-06

    Photoelectron spectroscopy of vibrationally cold singly and doubly charged higher fullerenes, Cn– and Cn2– (n = 76, 78, and 84), has been investigated at several photon energies. Vibrationally resolved spectra are obtained for both the singly and doubly charged species and for n = 78 and 84 transitions from different isomers are also observed. The electron affinities (EA’s) of C76, C78, and C84 are accurately determined to be 2.975±0.010 eV for C76, 3.20±0.01 eV for C78(C2v), 3.165±0.010 eV for C78(D3), 3.23±0.02 for C78(C2v’), 3.185±0.010 eV for C84(D2), and 3.26±0.02 eV for C84(D2d). The second EA’s of the higher fullerenes, which represent the electronic stability of the doubly charged anions, are measured to be 0.325±0.010 eV for C76, 0.44±0.02 eV for C78(C2v), 0.53±0.02 eV for C78(D3), 0.60±0.04 eV for C78(C2v’), 0.615±0.010 eV for C84(D2d), and 0.82±0.01 eV for C84(D2). The spectra of the dianions are observed to be similar to that of the singly charged anions, suggesting that the charging induces relatively small structural changes to the fullerene cages. The onsite Coulomb repulsions in the doubly charged fullerenes are directly measured from the differences of the first and second EA’s and reveal strong correlation effects between the two extra electrons. The repulsive Coulomb barriers in the doubly charged fullerenes are estimated from the cutoff in the photoelectron spectra and are found to be consistent with estimates from an electrostatic model.

  6. Mean carrier transport properties and charge collection dynamics of single-crystal, natural type IIa diamonds from ion-induced conductivity measurements

    Energy Technology Data Exchange (ETDEWEB)

    Han, Sung Su [Univ. of California, Berkeley, CA (United States)

    1993-09-01

    Ion-induced conductivity has been used to investigate the detector characteristics of diamond detectors. Both integrated-charge, and time-resolved current measurements were performed to examine the mean carrier transport properties of diamond and the dynamics of charge collection under highly-localized and high-density excitation conditions. The integrated-charge measurements were conducted with a standard pulse-counting system with 241Am radioactivity as the excitation source for the detectors. The time-resolved current measurements were performed using a 70 GHz random sampling oscilloscope with the detectors incorporated into high-speed microstrip transmission lines and the excitation source for these measurements was an ion beam of either 5-MeV He+ or 10-MeV Si3+. The detectors used in both experiments can be described as metal-semiconductor-metal (MSM) devices where a volume of the detector material is sandwiched between two metal plates. A charge collection model was developed to interpret the integrated-charge measurements which enabled estimation of the energy required to produce an electron-hole pair (ϵdi) and the mean carrier transport properties in diamond, such as carrier mobility and lifetime, and the behavior of the electrical contacts to diamond.

  7. Degradation of Adenine on the Martian Surface in the Presence of Perchlorates and Ionizing Radiation: A Reflectron Time-of-flight Mass Spectrometric Study

    Energy Technology Data Exchange (ETDEWEB)

    Góbi, Sándor; Bergantini, Alexandre; Kaiser, Ralf I., E-mail: ralfk@hawaii.edu [Department of Chemistry, University of Hawaii at Mānoa, Honolulu, HI 96822 (United States)

    2017-04-01

    The aim of the present work is to unravel the radiolytic decomposition of adenine (C{sub 5}H{sub 5}N{sub 5}) under conditions relevant to the Martian surface. Being the fundamental building block of (deoxy)ribonucleic acids, the possibility of survival of this biomolecule on the Martian surface is of primary importance to the astrobiology community. Here, neat adenine and adenine–magnesium perchlorate mixtures were prepared and irradiated with energetic electrons that simulate the secondary electrons originating from the interaction of the galactic cosmic rays with the Martian surface. Perchlorates were added to the samples since they are abundant—and therefore relevant oxidizers on the surface of Mars—and they have been previously shown to facilitate the radiolysis of organics such as glycine. The degradation of the samples were monitored in situ via Fourier transformation infrared spectroscopy and the electron ionization quadruple mass spectrometric method; temperature-programmed desorption profiles were then collected by means of the state-of-the-art single photon photoionization reflectron time-of-flight mass spectrometry (PI-ReTOF-MS), allowing for the detection of the species subliming from the sample. The results showed that perchlorates do increase the destruction rate of adenine by opening alternative reaction channels, including the concurrent radiolysis/oxidation of the sample. This new pathway provides a plethora of different radiolysis products that were identified for the first time. These are carbon dioxide (CO{sub 2}), isocyanic acid (HNCO), isocyanate (OCN{sup −}), carbon monoxide (CO), and nitrogen monoxide (NO); an oxidation product containing carbonyl groups (R{sub 1}R{sub 2}–C=O) with a constrained five-membered cyclic structure could also be observed. Cyanamide (H{sub 2}N–C≡N) was detected in both irradiated samples as well.

  8. Watson-Crick Base Pairing, Electronic and Photophysical Properties of Triazole Modified Adenine Analogues: A Computational Study

    KAUST Repository

    Das, Shubhajit

    2015-09-17

    We employ first-principles Density Functional Theory (DFT) and time-dependent DFT (TDDFT) to elucidate structural, electronic and optical properties of a few recently reported triazole adenine nucleobase analogues. The results are compared against the findings obtained for both natural adenine nucleobase and available experimental data. The optical absorption of these adenine analogues are calculated both in gas-phase and in solvent (methanol) using Polarized Continuum Model (PCM). We find that all the analogues show a red-shifted absorption profile as compared to adenine. Our simulated emission spectra in solvent compare fairly well with experimentally observed results. We investigate base paring ability of these adenine analogues with thymine. The calculations on the intrinsic stability of these base pairs ascertain that all the adenine analogues form the hydrogen bonded Watson-Crick base pair with similar H-bonding energy as obtained for natural adenine-thymine base pair. In our study, we provide a microscopic origin of the low-energy absorption and emission peaks, observed experimentally.

  9. Differences in Electrostatic Potential Around DNA Fragments Containing Adenine and 8-oxo-Adenine. An Analysis Based on Regular Cylindrical Projection

    Energy Technology Data Exchange (ETDEWEB)

    Haranczyk, Maciej; Miller, John H; Gutowski, Maciej S

    2007-07-01

    Changes of electrostatic potential (EP) around the DNA molecule resulting from chemical modifications of nucleotides may play a role in enzymatic recognition of damaged sites. Effects of chemical modifications of nucleotides on the structure of DNA have been characterized through large scale density functional theory computations. Quantum mechanical structural optimizations of DNA fragments with three pairs of nucleotides and accompanying counteractions were performed with a B3LYP exchange-correlation functional and 6-31G** basis sets. The “intact” DNA fragment contained adenine in the middle layer, while the “damaged” fragment had the adenine replaced with 8-oxo-adenine. The electrostatic potential around these DNA fragments was projected on a cylindrical surface around the double helix. The two-dimensional maps of EP of the intact and damaged DNA fragments were analyzed to identify these modifications of EP that result from the occurrence of 8-oxo-adenine (8oA). It was found that distortions of a phosphate group neighboring 8oA and displacements of the accompanying countercation are clearly reflected in the EP maps. Helpful discussions Michel Dupuis are gratefully acknowledged. Authors wish to thank Marcel Swart for directing us to a compilation of van der Waals radii. This work was supported by the: (i) US DOE Office of Biological and Environmental Research, Low Dose Radiation Research Program (M.G. and M.H.), (ii) the Office of Science (BER), U. S. Department of Energy, Grant No. DE-FG03-02ER63470 (JHM), (iii) Polish State Committee for Scientific Research (KBN) Grant DS/8221-4-0140-6 (MG), (iv) European Social Funds (EFS) ZPORR/2.22/II/2.6/ARP/U/2/05 (M.H.). M.H. holds the Foundation for Polish Science (FNP) award for young scientists. The calculations were performed at the Academic Computer Center in Gdansk (TASK) and at the Molecular Science Computing Facility (MSCF) in the William R. Wiley Environmental Molecular Sciences Laboratory, a national

  10. Experimental study on the fragmentation of Adenine and Porphyrin molecules induced by low energy multicharged ion impact

    International Nuclear Information System (INIS)

    Li, B.

    2010-01-01

    Since the dissociation of small molecules might play key roles in the understanding of radiation induced damages of living tissues at the primary steps and at the molecular levels, fragmentation dynamics of small biomolecules have drawn much attention. The knowledge of the internal energy is of fundamental importance for understanding its fragmentation dynamics following external excitation. For a long time however, it was difficult to measure this parameter in coincidence with the fragmentation patterns until the development of CIDEC (Collision Induced Dissociation under Energy Control) method in 2007. In this work, the CIDEC method was extended to study the fragmentation of gas-phase biomolecules adenine (Ade: H 5 C 5 N 5 ) and porphyrin chloride FeTPPCl (C 44 H 28 N 4 FeCl). The population distribution for each dissociation channel as a function of the excitation energy of the parent molecular ions at a well-determined initial charge state has been experimentally determined, which could shed some light on the fragmentation dynamics of these molecules. In collisions between Cl + and Ade at 3 keV, the fragmentation pattern of Ade 2+ is dominated by the loss of H 2 CN + and the successive emission of HCN. The energy distribution of the parent dication confirms the successive emission dynamics. A specific decay channel is observed, i.e. the emission of a charged H 2 CN + followed by the emission of HC 2 N 2 . The measured mean excitation energies of this channel and other competitive channels are compared. In Kr 8+ - FeTPPCl collisions at 80 keV, parent ions FeTPPCL 1+,2+,3+ are observed, along with the corresponding decay patterns. It is found that, in the first step the dominant low-energy-cost decay channel is the emission of Cl 0 independent of the initial charge state of FeTPPCl r+ . For the resulted dication FeTPP 2+ , the dominant fragmentation channel is the neutral evaporation; for the tri-cation however, the dominant fragmentation channel is the

  11. Experimental Charge Density in an Oxidized Trinuclear Iron Complex using 15 K Synchrotron and 100 K Conventional Single-Crystal X-ray Diffraction

    International Nuclear Information System (INIS)

    Overgaard, J.; Larsen, F.; Timco, G.; Iversen, B.

    2009-01-01

    The experimental electron density distribution in a crystal consisting of the simplest conceivable trinuclear carboxylate-bridged iron-μ3-oxo dianion with two α-picolinium cations has been determined using both synchrotron (15 K) and conventional (100 K) X-ray diffraction data. The constituent trinuclear oxo-centered molecule consists of six 2-bridging formate groups between the iron pairs, while the axial ligand for all iron atoms is another formate group. The compound {(Fe3O(HCOO)6(HCOO)3)2-·H2O·2(α-CH3NC5H5)+}, ( 1) crystallizes in the monoclinic space group P21/m with charge assisted hydrogen bonds linking the α-picolinium cations to the trinuclear groups. The chemical bonding in the weakly asymmetric Fe3O-core of 1 has been examined through the use of the quantum theory of atoms in molecules, and in combination with experimental d-orbital populations, a significant electron sharing is observed between the Fe atoms and the central oxygen. The central oxygen exhibits clear sp2 hybridization, and the iron atoms have valence shell charge concentrations in all metal-ligand bond directions. The relative bond strengths are evaluated based upon the charge density distribution and found to be in accordance with the geometrical results. Integrated group charges follow expectations from formal chemical valences.

  12. Measurements of the differential cross section and charge asymmetry for inclusive pp →W (muupsilon) production with 8 TeV CMS data and CMS single muon trigger efficiency study

    Science.gov (United States)

    Ogul, Hasan

    This dissertation presents muon charge asymmetry, fiducial differential cross section and CMS single muon trigger efficiency measurements as a function of muon pseudorapidity for inclusive W→muupsilon events produced in proton-proton collisions at the LHC. The data were recorded by the CMS detector at a center-of-mass energy of 8 TeV and correspond to an integrated luminosity of 18.8 fb-1. Several comparisons are performed to cross-check the experimental results. Muon efficiency measurements are compared to estimated values from Monte Carlo simulations and reference values recommended by CMS physics object groups. The differential cross section and the charge asymmetry measurements are compared to theoretical predictions based on next-to-leading order and next-to-next-to-leading order QCD calculations with different PDF models. Inputs from the charge asymmetry and the differential cross section measurements for the determination of the next generation of PDF sets are expected to bring different predictions closer together and aid in reducing PDF uncertainties. The impact of the charge asymmetry on PDFs has been investigated by putting the asymmetry results into a QCD analysis at next-to-leading order and next-to-nextleading order with inclusive deep-inelastic scattering data from HERA. Significant improvement of the accuracy on the valence-quark distributions is observed. This measurement is recommended for more accurate constraints in future PDF determinations. More precise measurements of PDFs will improve LHC predictions.

  13. Charge preamplifier

    International Nuclear Information System (INIS)

    Chaminade, R.; Passerieux, J.P.

    1961-01-01

    We describe a charge preamplifier having the following properties: - large open loop gain giving both stable gain and large input charge transfer; - stable input grid current with aging and without any adjustment; - fairly fast rise; - nearly optimum noise performance; - industrial material. (authors)

  14. Charging machine

    International Nuclear Information System (INIS)

    Medlin, J.B.

    1976-01-01

    A charging machine for loading fuel slugs into the process tubes of a nuclear reactor includes a tubular housing connected to the process tube, a charging trough connected to the other end of the tubular housing, a device for loading the charging trough with a group of fuel slugs, means for equalizing the coolant pressure in the charging trough with the pressure in the process tubes, means for pushing the group of fuel slugs into the process tube and a latch and a seal engaging the last object in the group of fuel slugs to prevent the fuel slugs from being ejected from the process tube when the pusher is removed and to prevent pressure liquid from entering the charging machine. 3 claims, 11 drawing figures

  15. Influence of gamma irradiation and benzyl adenine on keeping quality of custard apple fruits during storage

    International Nuclear Information System (INIS)

    Chouksey, Swati; Singh, Alpana; Thakur, Rajendra Singh; Deshmukh, Reena

    2013-01-01

    The custard apple (Annona squamosa) fruits were procured from local market, irradiated with radiation doses 0, 0.25, 0.50, 0.75, 1.00, 1.25, 1.50, 1.75 kGy and then treated with benzyl adenine (50 and 100 part per million) and stored at ambient temperature (25±5 °C, Relative Humidity 90±2%) for 12 days. The treated fruits were evaluated for sensory (viz; flavour, texture, internal and external colour) and chemical constituents (viz; Total Soluble Solids, titrable acidity, ascorbic acid, free soluble sugar, reducing sugar, non reducing sugar, carbohydrate) during storage. The study concluded that radiation dose of 1.5 kilo Gray along with 50 ppm benzyl adenine enhanced in shelf-life of custard apple fruits by 6 days at ambient temperature with good pulp texture, flavour, colour and nutritional quality as compared to control. (author)

  16. Adenine Synthesis in a Model Prebiotic Reaction: Connecting Origin of Life Chemistry with Biology

    OpenAIRE

    Anumukonda, Lakshmi N.; Young, Avery; Lynn, David G.; Buckley, Ragan; Warrayat, Amena; Graves, Christina L.; Bean, Heather D.; Hud, Nicholas V.

    2011-01-01

    Many high school laboratory experiments demonstrate concepts related to biological evolution, but few exist that allow students to investigate life?s chemical origins. This series of laboratory experiments has been developed to allow students to explore and appreciate the deep connection that exists between prebiotic chemistry, chemical evolution, and contemporary biological systems. In the first experiment of the series, students synthesize adenine, one of the purine nucleobases of DNA and R...

  17. Adenine ribbon stabilized by Watson–Crick and Hoogsteen hydrogen Bonds: WFT and DFT study

    Czech Academy of Sciences Publication Activity Database

    Zierkiewicz, W.; Michalska, D.; Hobza, Pavel

    2010-01-01

    Roč. 12, č. 12 (2010), s. 2888-2894 ISSN 1463-9076 R&D Projects: GA MŠk LC512 Grant - others:Wroclaw University of Technology(PL) 343974/Z0304 Institutional research plan: CEZ:AV0Z40550506 Keywords : adenine ribbon * ab initio correlated calculations * self -organization Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.454, year: 2010

  18. Design, synthesis, and characterization of 0-D, 1-D, and 2-D Zinc–Adeninate coordination assemblies

    Energy Technology Data Exchange (ETDEWEB)

    An, Ji Hyun [Dept. of Chemistry Education, Seoul National University, Seoul (Korea, Republic of); Geib, Steven J. [Dept. of Chemistry, University of Pittsburgh, Pittsburgh (United States); Kim, Myung Gil [Dept. of Chemistry, Chungang University, Seoul (Korea, Republic of)

    2015-08-15

    In this study, we demonstrate the synthesis and characterization of zinc– adeninate coordination polymers with 0-D, 1-D, and 2-D structures. We describe methods for controlling the structure of these materials by applying different synthetic conditions and discuss their structural relationships. 0-D, 1-D, and 2-D zinc–adeninate coordination polymers with the same metal–adeninate coordination mode were synthesized and characterized. By controlling the temperature, a material with 0-D macrocycle or 1-D chain coordination polymer was prepared. A replacement of pyridine with bipyridine formed 2-D sheet structure by connecting 1-D chains with each other. They exhibited an interesting relationship between synthetic methods and structures. Further study of metal–adeninate coordination chemistry will render a precise control of the structure in synthesis and will open a new venue to new materials with fascinating properties.

  19. Terahertz spectra revealing the collective excitation mode in charge-density-wave single crystal LuFe{sub 2}O{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xiumei; Jin, Zuanming; Lin, Xian; Ma, Guohong [Department of Physics, Shanghai University (China); Cheng, Zhenxiang [Institute for Superconducting and Electronic Materials, University of Wollongong, NSW (Australia); Balakrishnan, Geetha [Department of Physics, University of Warwick, Coventry (United Kingdom)

    2017-09-15

    A low-energy collective excitation mode in charge-ordered multiferroic LuFe{sub 2}O{sub 4} is reported via terahertz time-domain spectroscopy. Upon cooling from 300 to 40 K, the central resonance frequency showed a pronounced hardening from 0.85 to 1.15 THz. In analogy to the well-known low-energy optical properties of LuFe{sub 2}O{sub 4}, this emerging resonance was attributed to the charge-density-wave (CDW) collective excitations. By using the Drude-Lorentz model fitting, the CDW collective mode becomes increasingly damped with the increasing temperature. Furthermore, the kinks of the CDW collective mode at the magnetic transition temperature are analyzed, which indicate the coupling of spin order with electric polarization. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  20. Ethanol-induced activation of adenine nucleotide turnover. Evidence for a role of acetate

    International Nuclear Information System (INIS)

    Puig, J.G.; Fox, I.H.

    1984-01-01

    Consumption of alcohol causes hyperuricemia by decreasing urate excretion and increasing its production. Our previous studies indicate that ethanol administration increases uric acid production by increasing ATP degradation to uric acid precursors. To test the hypothesis that ethanol-induced increased urate production results from acetate metabolism and enhanced adenosine triphosphate turnover, we gave intravenous sodium acetate, sodium chloride and ethanol (0.1 mmol/kg per min for 1 h) to five normal subjects. Acetate plasma levels increased from 0.04 +/- 0.01 mM (mean +/- SE) to peak values of 0.35 +/- 0.07 mM and to 0.08 +/- 0.01 mM during acetate and ethanol infusions, respectively. Urinary oxypurines increased to 223 +/- 13% and 316 +/- 44% of the base-line values during acetate and ethanol infusions, respectively. Urinary radioactivity from the adenine nucleotide pool labeled with [8-14C] adenine increased to 171 +/- 27% and to 128 +/- 8% of the base-line values after acetate and ethanol infusions. These data indicate that both ethanol and acetate increase purine nucleotide degradation by enhancing the turnover of the adenine nucleotide pool. They support the hypothesis that acetate metabolism contributes to the increased production of urate associated with ethanol intake

  1. Adenine Synthesis in a Model Prebiotic Reaction: Connecting Origin of Life Chemistry with Biology.

    Science.gov (United States)

    Anumukonda, Lakshmi N; Young, Avery; Lynn, David G; Buckley, Ragan; Warrayat, Amena; Graves, Christina L; Bean, Heather D; Hud, Nicholas V

    2011-12-01

    Many high school laboratory experiments demonstrate concepts related to biological evolution, but few exist that allow students to investigate life's chemical origins. This series of laboratory experiments has been developed to allow students to explore and appreciate the deep connection that exists between prebiotic chemistry, chemical evolution, and contemporary biological systems. In the first experiment of the series, students synthesize adenine, one of the purine nucleobases of DNA and RNA, from plausibly prebiotic precursor molecules. Students compare their product to authentic standards using thin-layer chromatography. The second and third experiments of the series allow students to extract DNA from a familiar organism, the strawberry, and hydrolyze it, releasing adenine, which they can then compare to the previously chemically-synthesized adenine. A fourth, optional experiment is included where the technique of thin-layer chromatography is introduced and chromatographic skills are developed for use in the other three experiments that comprise this series. Concepts relating to organic and analytical chemistry, as well as biochemistry and DNA structure, are incorporated throughout, allowing this series of laboratory experiments to be easily inserted into existing laboratory courses and to reinforce concepts already included in any high school chemistry or biology curriculum.

  2. Selective self-assembly of adenine-silver nanoparticles forms rings resembling the size of cells

    Science.gov (United States)

    Choi, Sungmoon; Park, Soonyoung; Yang, Seon-Ah; Jeong, Yujin; Yu, Junhua

    2015-01-01

    Self-assembly has played critical roles in the construction of functional nanomaterials. However, the structure of the macroscale multicomponent materials built by the self-assembly of nanoscale building blocks is hard to predict due to multiple intermolecular interactions of great complexity. Evaporation of solvents is usually an important approach to induce kinetically stable assemblies of building blocks with a large-scale specific arrangement. During such a deweting process, we tried to monitor the possible interactions between silver nanoparticles and nucleobases at a larger scale by epifluorescence microscopy, thanks to the doping of silver nanoparticles with luminescent silver nanodots. ssDNA oligomer-stabilized silver nanoparticles and adenine self-assemble to form ring-like compartments similar to the size of modern cells. However, the silver ions only dismantle the self-assembly of adenine. The rings are thermodynamically stable as the drying process only enrich the nanoparticles-nucleobase mixture to a concentration that activates the self-assembly. The permeable membrane-like edge of the ring is composed of adenine filaments glued together by silver nanoparticles. Interestingly, chemicals are partially confined and accumulated inside the ring, suggesting that this might be used as a microreactor to speed up chemical reactions during a dewetting process. PMID:26643504

  3. [Adenine nucleotides and metabolites of glycolysis in the liver in auxiliary transplantation].

    Science.gov (United States)

    Röhnert, C; Weber, K; Schuster, R; Lauschke, G; Häcker, R

    1982-07-01

    The metabolic state of the liver during preservation as well as in and after auxiliary transplantation was investigated in dogs. The biopsy was carried out by means of TRU-CUT biopsy needle. - The ATP concentration, the storage of energy, the amount of the adenine nucleotides, and the ATP/ADP quotient decrease in the preserved liver. The AMP concentration, the concentration of the hexosemonophosphates and the mass-effective quotient of the phosphofructokinase increase simultaneously. The energy supply is the glycolysis exclusively. A lactate accumulation is avoided by continuous perfusion. - The changeover of the anaerobic to the aerobic energy preparation took place by degrees after the recovery of the liver circulation. The ATP concentration, the ATP/ADP quotient, the storage of energy, and the amount of the adenine nucleotides increase in the transplanted liver. - An irreversible ischemic damage of the liver appears in the metabolic state of the organ by a massive decrease of the ATP concentration below 0.7 mmol/kg, the amount of the adenine nucleotides below 1.8 mmol/kg, and AMP concentration.

  4. Quantification of DNA in Neonatal Dried Blood Spots by Adenine Tandem Mass Spectrometry.

    Science.gov (United States)

    Durie, Danielle; Yeh, Ed; McIntosh, Nathan; Fisher, Lawrence; Bulman, Dennis E; Birnboim, H Chaim; Chakraborty, Pranesh; Al-Dirbashi, Osama Y

    2018-01-02

    Newborn screening programs have expanded to include molecular-based assays as first-tier tests and the success of these assays depends on the quality and yield of DNA extracted from neonatal dried blood spots (DBS). To meet high throughput and rapid turnaround time requirements, newborn screening laboratories adopted rapid DNA extraction methods that produce crude extracts. Quantification of DNA in neonatal DBS is not routinely performed due to technical challenges; however, this may enhance the performance of assays that are sensitive to amounts of input DNA. In this study, we developed a novel high throughput method to quantify total DNA in DBS. It is based on specific acid-catalyzed depurination of DNA followed by mass spectrometric quantification of adenine. The amount of adenine was used to calculate DNA quantity per 3.2 mm DBS. Reference intervals were established using archived, neonatal DBS (n = 501) and a median of 130.6 ng of DNA per DBS was obtained, which is in agreement with literature values. The intra- and interday variations were quantification were 12.5 and 37.8 nmol/L adenine, respectively. We demonstrated that DNA from neonatal DBS can be successfully quantified in high throughput settings using instruments currently deployed in NBS laboratories.

  5. CHARGE syndrome

    Directory of Open Access Journals (Sweden)

    Prasad Chitra

    2006-09-01

    Full Text Available Abstract CHARGE syndrome was initially defined as a non-random association of anomalies (Coloboma, Heart defect, Atresia choanae, Retarded growth and development, Genital hypoplasia, Ear anomalies/deafness. In 1998, an expert group defined the major (the classical 4C's: Choanal atresia, Coloboma, Characteristic ears and Cranial nerve anomalies and minor criteria of CHARGE syndrome. Individuals with all four major characteristics or three major and three minor characteristics are highly likely to have CHARGE syndrome. However, there have been individuals genetically identified with CHARGE syndrome without the classical choanal atresia and coloboma. The reported incidence of CHARGE syndrome ranges from 0.1–1.2/10,000 and depends on professional recognition. Coloboma mainly affects the retina. Major and minor congenital heart defects (the commonest cyanotic heart defect is tetralogy of Fallot occur in 75–80% of patients. Choanal atresia may be membranous or bony; bilateral or unilateral. Mental retardation is variable with intelligence quotients (IQ ranging from normal to profound retardation. Under-development of the external genitalia is a common finding in males but it is less apparent in females. Ear abnormalities include a classical finding of unusually shaped ears and hearing loss (conductive and/or nerve deafness that ranges from mild to severe deafness. Multiple cranial nerve dysfunctions are common. A behavioral phenotype for CHARGE syndrome is emerging. Mutations in the CHD7 gene (member of the chromodomain helicase DNA protein family are detected in over 75% of patients with CHARGE syndrome. Children with CHARGE syndrome require intensive medical management as well as numerous surgical interventions. They also need multidisciplinary follow up. Some of the hidden issues of CHARGE syndrome are often forgotten, one being the feeding adaptation of these children, which needs an early aggressive approach from a feeding team. As the child

  6. An experimental and theoretical vibrational study of interaction of adenine and thymine with artificial seawaters: A prebiotic chemistry experiment.

    Science.gov (United States)

    Anizelli, Pedro R; Baú, João P T; Nabeshima, Henrique S; da Costa, Marcello F; de Santana, Henrique; Zaia, Dimas A M

    2014-05-21

    Nucleic acid bases play important roles in living beings. Thus, their interaction with salts the prebiotic Earth could be an important issue for the understanding of origin of life. In this study, the effect of pH and artificial seawaters on the structure of adenine and thymine was studied via parallel determinations using FT-IR, Raman spectroscopy and theoretical calculations. Thymine and adenine lyophilized in solutions at basic and acidic conditions showed characteristic bands of the enol-imino tautomer due to the deprotonation and the hydrochloride form due to protonation, respectively. The interaction of thymine and adenine with different seawaters representative of different geological periods on Earth was also studied. In the case of thymine a strong interaction with Sr(2+) promoted changes in the Raman and infrared spectra. For adenine changes in infrared and Raman spectra were observed in the presence of salts from all seawaters tested. The experimental results were compared to theoretical calculations, which showed structural changes due to the presence of ions Na(+), Mg(2+), Ca(2+) and Sr(2+) of artificial seawaters. For thymine the bands arising from C4=C5 and C6=O stretching were shifted to lower values, and for adenine, a new band at 1310cm(-1) was observed. The reactivity of adenine and thymine was studied by comparing changes in nucleophilicity and energy of the HOMO orbital. Copyright © 2014 Elsevier B.V. All rights reserved.

  7. Prolonged Pulmonary Exposure to Diesel Exhaust Particles Exacerbates Renal Oxidative Stress, Inflammation and DNA Damage in Mice with Adenine-Induced Chronic Renal Failure

    Directory of Open Access Journals (Sweden)

    Abderrahim Nemmar

    2016-05-01

    Full Text Available Background/Aims: Epidemiological evidence indicates that patients with chronic kidney diseases have increased susceptibility to adverse outcomes related to long-term exposure to particulate air pollution. However, mechanisms underlying these effects are not fully understood. Methods: Presently, we assessed the effect of prolonged exposure to diesel exhaust particles (DEP on chronic renal failure induced by adenine (0.25% w/w in feed for 4 weeks, which is known to involve inflammation and oxidative stress. DEP (0.5m/kg was intratracheally (i.t. instilled every 4th day for 4 weeks (7 i.t. instillation. Four days following the last exposure to either DEP or saline (control, various renal endpoints were measured. Results: While body weight was decreased, kidney weight increased in DEP+adenine versus saline+adenine or DEP. Water intake, urine volume, relative kidney weight were significantly increased in adenine+DEP versus DEP and adenine+saline versus saline. Plasma creatinine and urea increased and creatinine clearance decreased in adenine+DEP versus DEP and adenine+saline versus saline. Tumor necrosis factor α, lipid peroxidation and reactive oxygen species were significantly increased in adenine+DEP compared with either DEP or adenine+saline. The antioxidant calase was significantly decreased in adenine+DEP compared with either adenine+saline or DEP. Notably, renal DNA damage was significantly potentiated in adenine+DEP compared with either adenine+saline or DEP. Similarly, systolic blood pressure was increased in adenine+DEP versus adenine+saline or DEP, and in DEP versus saline. Histological evaluation revealed more collagen deposition, higher number of necrotic cell counts and dilated tubules, cast formation and collapsing glomeruli in adenine+DEP versus adenine+saline or DEP. Conclusion: Prolonged pulmonary exposure to diesel exhaust particles worsen renal oxidative stress, inflammation and DNA damage in mice with adenine-induced chronic

  8. Field calculations, single-particle tracking, and beam dynamics with space charge in the electron lens for the Fermilab Integrable Optics Test Accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Noll, Daniel [Goethe Univ., Frankfurt (Germany); Stancari, Giulio [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)

    2015-11-17

    An electron lens is planned for the Fermilab Integrable Optics Test Accelerator as a nonlinear element for integrable dynamics, as an electron cooler, and as an electron trap to study space-charge compensation in rings. We present the main design principles and constraints for nonlinear integrable optics. A magnetic configuration of the solenoids and of the toroidal section is laid out. Singleparticle tracking is used to optimize the electron path. Electron beam dynamics at high intensity is calculated with a particle-in-cell code to estimate current limits, profile distortions, and the effects on the circulating beam. In the conclusions, we summarize the main findings and list directions for further work.

  9. Single-reversal charge in the β10-β11 receptor-binding loop of Bacillus thuringiensis Cry4Aa and Cry4Ba toxins reflects their different toxicity against Culex spp. larvae.

    Science.gov (United States)

    Visitsattapongse, Sarinporn; Sakdee, Somsri; Leetacheewa, Somphob; Angsuthanasombat, Chanan

    2014-07-25

    Bacillus thuringiensis Cry4Aa toxin was previously shown to be much more toxic to Culex mosquito-larvae than its closely related toxin - Cry4Ba, conceivably due to their sequence differences within the β10-β11 receptor-binding loop. Here, single-Ala substitutions of five residues (Pro(510), Thr(512), Tyr(513), Lys(514) and Thr(515)) within the Cry4Aa β10-β11 loop revealed that only Lys(514) corresponding to the relative position of Cry4Ba-Asp(454) is crucial for toxicity against Culex quinquefasciatus larvae. Interestingly, charge-reversal mutations at Cry4Ba-Asp(454) (D454R and D454K) revealed a marked increase in toxicity against such less-susceptible larvae. In situ binding analyses revealed that both Cry4Ba-D454R and D454K mutants exhibited a significant increase in binding to apical microvilli of Culex larval midguts, albeit at lower-binding activity when compared with Cry4Aa. Altogether, our present data suggest that a positively charged side-chain near the tip of the β10-β11 loop plays a critical role in determining target specificity of Cry4Aa against Culex spp., and hence a great increase in the Culex larval toxicity of Cry4Ba was obtained toward an opposite-charge conversion of the corresponding Asp(454). Copyright © 2014 Elsevier Inc. All rights reserved.

  10. Measurement of Absolute Single and Double Charge Exchange Cross Sections for Si(7–10)+ at 0.88–2.50 KeV/u Impacting He and H2

    Science.gov (United States)

    Moradmand, A.; El Ghazaly, M. O. A.; Mahaptra, D. P.; Chutjian, A.

    2018-01-01

    First measurements are reported for total, absolute, single, and double charge-exchange (CE) cross sections for Si(7–10)+ ions in the solar wind (SW), colliding with the prevalent astrophysical species H2 and He found in comets, the interplanetary medium, and planetary atmospheres. Measurements are in the energy range 0.88–2.50 keV/u, corresponding to the energies of the “fast” and “slow” ion components of the SW. Limited agreement is found with single-exchange results calculated in the classical over-the-barrier model. These CE data are useful for understanding, in laboratory and astrophysical plasmas, photon emissions in the X-ray to visible energy range arising from resulting ion-stabilization steps.

  11. Search for top quark partners with charge 5/3 in the single-lepton final state at $\\sqrt{s}=13~\\mathrm{TeV}$

    CERN Document Server

    CMS Collaboration

    2017-01-01

    A search for the pair production of heavy partners of the top quark with an exotic electric charge 5/3 ($X_{5/3}$) decaying into a W boson and a top quark is presented. The search uses data collected in 2016 in proton-proton collisions at a center-of-mass energy of $13~\\mathrm{TeV}$ with the CMS detector at the CERN LHC, corresponding to an integrated luminosity of $35.9~\\mathrm{fb}^{-1}$. Final states considered include one electron or muon, missing transverse energy, and four or more jets. The $X_{5/3}$ masses with right-handed (left-handed) couplings below 1.32 (1.30) $\\mathrm{TeV}$ are excluded at $95\\%$ confidence level.

  12. Influence of the single EGR valve usability on development of the charge directed to individual cylinders of an internal combustion engine

    Directory of Open Access Journals (Sweden)

    Krakowian Konrad

    2017-01-01

    Full Text Available Exhaust gas recirculation systems (EGR, aside to a catalytic converters, are nowadays widely used in piston internal combustion engines to reduce nitrogen oxides (NOx in the exhaust gas. They are characterized in that a portion of exhaust gases from the exhaust manifold is recirculated (via a condenser, and directed to a particular valve. The valve, depending on the current engine load and speed, doses the appropriate amount of exhaust gas into the exhaust manifold. Moreover, its location has a significant impact on the diverse formation of nitrogen oxides and fumes smokiness from the individual cylinders of the engine, which is a result of uneven propagation of exhaust gas into the channels of the intake manifold. This article contains the results of numerical characterized charges formed in symmetrical intake manifold with a centrally–placed EGR valve. Simulations were performed for the original intake system derived from the two-liter, turbocharged VW diesel engine.

  13. Influence of the single EGR valve usability on development of the charge directed to individual cylinders of an internal combustion engine

    Science.gov (United States)

    Krakowian, Konrad; Kaźmierczak, Andrzej; Górniak, Aleksander; Wróbel, Radosław

    2017-11-01

    Exhaust gas recirculation systems (EGR), aside to a catalytic converters, are nowadays widely used in piston internal combustion engines to reduce nitrogen oxides (NOx) in the exhaust gas. They are characterized in that a portion of exhaust gases from the exhaust manifold is recirculated (via a condenser), and directed to a particular valve. The valve, depending on the current engine load and speed, doses the appropriate amount of exhaust gas into the exhaust manifold. Moreover, its location has a significant impact on the diverse formation of nitrogen oxides and fumes smokiness from the individual cylinders of the engine, which is a result of uneven propagation of exhaust gas into the channels of the intake manifold. This article contains the results of numerical characterized charges formed in symmetrical intake manifold with a centrally-placed EGR valve. Simulations were performed for the original intake system derived from the two-liter, turbocharged VW diesel engine.

  14. Charge density analysis of SiO sub 2 under pressures over 50 GPa using a new diamond anvil cell for single-crystal structure analysis

    CERN Document Server

    Yamanaka, T; Komatsu, Y; Sumiya, H

    2002-01-01

    Single-crystal structure analysis of SiO sub 2 stishovite, (rutile type, P4 sub 2 /mnm z = 2) was carried out using the newly devised diamond anvil cell. The electron-density distribution was investigated at high pressures up to 50 GPa using synchrotron radiation at SPring-8 and a laboratory x-ray source generator of Ag K alpha rotating anode generator. Using large diamond crystal windows instead of beryllium for the cell has several advantages for single-crystal diffraction study supplying the large Q-value.

  15. Functional analysis of an acid adaptive DNA adenine methyltransferase from Helicobacter pylori 26695.

    Directory of Open Access Journals (Sweden)

    Arun Banerjee

    Full Text Available HP0593 DNA-(N(6-adenine-methyltransferase (HP0593 MTase is a member of a Type III restriction-modification system in Helicobacter pylori strain 26695. HP0593 MTase has been cloned, overexpressed and purified heterologously in Escherichia coli. The recognition sequence of the purified MTase was determined as 5'-GCAG-3'and the site of methylation was found to be adenine. The activity of HP0593 MTase was found to be optimal at pH 5.5. This is a unique property in context of natural adaptation of H. pylori in its acidic niche. Dot-blot assay using antibodies that react specifically with DNA containing m6A modification confirmed that HP0593 MTase is an adenine-specific MTase. HP0593 MTase occurred as both monomer and dimer in solution as determined by gel-filtration chromatography and chemical-crosslinking studies. The nonlinear dependence of methylation activity on enzyme concentration indicated that more than one molecule of enzyme was required for its activity. Analysis of initial velocity with AdoMet as a substrate showed that two molecules of AdoMet bind to HP0593 MTase, which is the first example in case of Type III MTases. Interestingly, metal ion cofactors such as Co(2+, Mn(2+, and also Mg(2+ stimulated the HP0593 MTase activity. Preincubation and isotope partitioning analyses clearly indicated that HP0593 MTase-DNA complex is catalytically competent, and suggested that DNA binds to the MTase first followed by AdoMet. HP0593 MTase shows a distributive mechanism of methylation on DNA having more than one recognition site. Considering the occurrence of GCAG sequence in the potential promoter regions of physiologically important genes in H. pylori, our results provide impetus for exploring the role of this DNA MTase in the cellular processes of H. pylori.

  16. In vitro propagation of Calla lily: adenine sulphate and 6-benzilaminopurine

    Directory of Open Access Journals (Sweden)

    Márcia De Nazaré Oliveira Ribeiro

    2014-09-01

    Full Text Available Calla lily [Zantedeschia aethiopica (L. Spreng.] belonging to the Araceae family is appreciated as cut flower and in com­position of gardens. However, the conventional propagation of this plants shows a poor productive. Thus, tissue culture besides allowing fast clonal propagation also provides healthy and uniforms plants. The aim was study the influence of the differents concentrations of 6-benzilaminopurine (BAP and adenine sulphate (AS on in vitro multiplication of Calla lily. The explants were maintained in MS medium added with BAP (0.0, 8.9, 17.8 and 26.7 μM and adenine sulphate (0, 54, 108 and 162 μM. The plants were transferred to growth room and maintained at 25±1ºC and photoperiod of 16 hours for 60 days, under luminous intensity of 35 μmol m-2 s-1, for a period of 60 days. The experimental design was entirely randomized with four repetitions of three seedlings each, resulting in twelve plants per treatment, each tube with one plant. The statistics analysis showed interactive effects for quantify of BAP and AS for leaves number and fresh mass of the aerial parts. The highest number of leaves (4.8 and fresh mass of aerial parts (0.73 g was obtained with 26.7 μM of BAP combined with 108 μM of AS, highest number of shoots (2.6 was obtained with 22,19 μM of BAP and highest lengh of sprouts (5.0 cm was observed in the absence of BAP. The addition of BAP increased the number of shoots per explant. The use of adenine sulphate in combination with BAP had a positive effect for the accumulation of fresh weight and number of leaves in vitro culture.

  17. Efficacy of Adenine in the Treatment of Leukopenia and Neutropenia Associated with an Overdose of Antipsychotics or Discontinuation of Lithium Carbonate Administration: Three Case Studies

    OpenAIRE

    Tomita, Takashi; Goto, Hidekazu; Sumiya, Kenji; Yoshida, Tadashi; Tanaka, Katsuya; Kohda, Yukinao

    2016-01-01

    Because adenine is effective for managing cases of radiation-induced and drug-induced leukopenia, it may be effective in cases of antipsychotic-induced leukopenia and neutropenia. Here, we report our experience with patients with leukopenia and neutropenia caused by an antipsychotic overdose or discontinuation of lithium carbonate, in whom adenine administration ameliorated the white blood cell and neutrophil counts. The progress of patients suggests that adenine is effective in cases of leuk...

  18. Synthesis and Characterization of Oligodeoxyribonucleotides Modified with 2'-Amino-α-l-LNA Adenine Monomers

    DEFF Research Database (Denmark)

    Andersen, Nicolai K; Anderson, Brooke A; Wengel, Jesper

    2013-01-01

    thereof. Oligonucleotides modified with these units display greatly increased affinity toward nucleic acid targets, improved binding specificity, and enhanced enzymatic stability relative to unmodified strands. Here we present the synthesis and biophysical characterization of oligodeoxyribonucleotides....... ONs modified with pyrene-functionalized 2'-amino-α-l-LNA adenine monomers X-Z display greatly increased affinity toward DNA targets (ΔTm/modification up to +14 °C). Results from absorption and fluorescence spectroscopy suggest that the duplex stabilization is a result of pyrene intercalation....... These characteristics render N2'-pyrene-functionalized 2'-amino-α-l-LNAs of considerable interest for DNA-targeting applications....

  19. No evidence for cognitive improvement from oral nicotinamide adenine dinucleotide (NADH) in dementia.

    Science.gov (United States)

    Rainer, M; Kraxberger, E; Haushofer, M; Mucke, H A; Jellinger, K A

    2000-01-01

    Reduced nicotinamide adenine dinucleotide (NADH) is advertised as an over-the-counter product or dietary supplement to treat Alzheimer's disease. We performed a 3-month open-label study with oral 10 mg/day NADH with 25 patients with mild to moderate dementia of the Alzheimer, vascular, and fronto-temporal types in addition to their current cholinomimetic drug medication. In 19 patients who completed the study, we found no evidence for any cognitive effect as defined by established psychometric tests. We conclude that NADH is unlikely to achieve cognitive improvements in an extent reported earlier, and present theoretical arguments against an effectiveness of this compound in dementia disorders.

  20. Charge Breeding of Radioactive Ions

    CERN Document Server

    Wenander, F J C

    2013-01-01

    Charge breeding is a technique to increase the charge state of ions, in many cases radioactive ions. The singly charged radioactive ions, produced in an isotope separator on-line facility, and extracted with a low kinetic energy of some tens of keV, are injected into a charge breeder, where the charge state is increased to Q. The transformed ions are either directed towards a dedicated experiment requiring highly charged ions, or post-accelerated to higher beam energies. In this paper the physics processes involved in the production of highly charged ions will be introduced, and the injection and extraction beam parameters of the charge breeder defined. A description of the three main charge-breeding methods is given, namely: electron stripping in gas jet or foil; external ion injection into an electron-beam ion source/trap (EBIS/T); and external ion injection into an electron cyclotron resonance ion source (ECRIS). In addition, some preparatory devices for charge breeding and practical beam delivery aspects ...

  1. Synthesis, spectroscopic, structural and thermal characterizations of vanadyl(IV) adenine complex prospective as antidiabetic drug agent.

    Science.gov (United States)

    El-Megharbel, Samy M; Hamza, Reham Z; Refat, Moamen S

    2015-01-25

    The vanadyl(IV) adenine complex; [VO(Adn)2]⋅SO4; was synthesized and characterized. The molar conductivity of this complex was measured in DMSO solution that showed an electrolyte nature. Spectroscopic investigation of the green solid complex studied here indicate that the adenine acts as a bidentate ligand, coordinated to vanadyl(IV) ions through the nitrogen atoms N7 and nitrogen atom of amino group. Thus, from the results presented the vanadyl(IV) complex has square pyramid geometry. Further characterizations using thermal analyses and scanning electron techniques was useful. The aim of this paper was to introduce a new drug model for the diabetic complications by synthesized a novel mononuclear vanadyl(IV) adenine complex to mimic insulin action and reducing blood sugar level. The antidiabetic ability of this complex was investigated in STZ-induced diabetic mice. The results suggested that VO(IV)/adenine complex has antidiabetic activity, it improved the lipid profile, it improved liver and kidney functions, also it ameliorated insulin hormone and blood glucose levels. The vanadyl(IV) complex possesses an antioxidant activity and this was clear through studying SOD, CAT, MDA, GSH and methionine synthase. The current results support the therapeutic potentiality of vanadyl(IV)/adenine complex for the management and treatment of diabetes. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. Comparative study between transcriptionally- and translationally-acting adenine riboswitches reveals key differences in riboswitch regulatory mechanisms.

    Directory of Open Access Journals (Sweden)

    Jean-François Lemay

    2011-01-01

    Full Text Available Many bacterial mRNAs are regulated at the transcriptional or translational level by ligand-binding elements called riboswitches. Although they both bind adenine, the adenine riboswitches of Bacillus subtilis and Vibrio vulnificus differ by controlling transcription and translation, respectively. Here, we demonstrate that, beyond the obvious difference in transcriptional and translational modulation, both adenine riboswitches exhibit different ligand binding properties and appear to operate under different regulation regimes (kinetic versus thermodynamic. While the B. subtilis pbuE riboswitch fully depends on co-transcriptional binding of adenine to function, the V. vulnificus add riboswitch can bind to adenine after transcription is completed and still perform translation regulation. Further investigation demonstrates that the rate of transcription is critical for the B. subtilis pbuE riboswitch to perform efficiently, which is in agreement with a co-transcriptional regulation. Our results suggest that the nature of gene regulation control, that is transcription or translation, may have a high importance in riboswitch regulatory mechanisms.

  3. Synthesis, spectroscopic, structural and thermal characterizations of vanadyl(IV) adenine complex prospective as antidiabetic drug agent

    Science.gov (United States)

    El-Megharbel, Samy M.; Hamza, Reham Z.; Refat, Moamen S.

    2015-01-01

    The vanadyl(IV) adenine complex; [VO(Adn)2]ṡSO4; was synthesized and characterized. The molar conductivity of this complex was measured in DMSO solution that showed an electrolyte nature. Spectroscopic investigation of the green solid complex studied here indicate that the adenine acts as a bidentate ligand, coordinated to vanadyl(IV) ions through the nitrogen atoms N7 and nitrogen atom of amino group. Thus, from the results presented the vanadyl(IV) complex has square pyramid geometry. Further characterizations using thermal analyses and scanning electron techniques was useful. The aim of this paper was to introduce a new drug model for the diabetic complications by synthesized a novel mononuclear vanadyl(IV) adenine complex to mimic insulin action and reducing blood sugar level. The antidiabetic ability of this complex was investigated in STZ-induced diabetic mice. The results suggested that VO(IV)/adenine complex has antidiabetic activity, it improved the lipid profile, it improved liver and kidney functions, also it ameliorated insulin hormone and blood glucose levels. The vanadyl(IV) complex possesses an antioxidant activity and this was clear through studying SOD, CAT, MDA, GSH and methionine synthase. The current results support the therapeutic potentiality of vanadyl(IV)/adenine complex for the management and treatment of diabetes.

  4. The density functional study of electronic structure, electronic charge density, linear and nonlinear optical properties of single crystal alpha-LiAlTe{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Reshak, A.H. [New Technologies-Research Center, University of West Bohemia, Univerzitni 8, 306 14 Pilsen (Czech Republic); Center of Excellence Geopolymer and Green Technology, School of Material Engineering, University Malaysia Perlis, 01007 Kangar, Perlis (Malaysia); Khan, Wilayat, E-mail: walayat76@gmail.com [New Technologies-Research Center, University of West Bohemia, Univerzitni 8, 306 14 Pilsen (Czech Republic)

    2014-04-01

    Highlights: • FP-LAPW technique is used for calculating the electronic structure. • The band structure shows that the calculated compound is semiconductor. • The complex dielectric function has been calculated. • Nonlinear optical properties has also been calculated. • This compound can be used for molecular engineering of the crystals. - Abstract: Self-consistent calculations is performed using the full potential linear augmented plane wave (FP-LAPW) technique based on density functional theory (DFT) to investigate the electronic band structure, density of states, electronic charge density, linear and non-linear optical properties of α-LiAlTe{sub 2} compound having tetragonal symmetry with space group I4{sup ¯}2d. The electronic structure are calculated using the Ceperley Alder local density approach (CA-LDA), Perdew Burke and Ernzerhof generalize gradient approach (PBE-GGA), Engel–Vosko generalize gradient approach (EVGGA) and modified Becke Johnson approach (mBJ). Band structure calculations of (α-LiAlTe{sub 2}) depict semiconducting nature with direct band gap of 2.35 eV (LDA), 2.48 eV (GGA), 3.05 eV (EVGGA) and 3.13 eV (mBJ), which is comparable to experimental value. The calculated electronic charge density show ionic interaction between Te and Li atoms and polar covalent interaction between Al and Te atoms. Some optical susceptibilities like dielectric constants, refractive index, extension co-efficient, reflectivity and energy loss function have been calculated and analyzed on the basis of electronic structure. The compound α-LiAlTe{sub 2} provides a considerable negative value of birefringence of −0.01. Any anisotropy observed in the linear optical properties which are in favor to enhance the nonlinear optical properties. The symbol χ{sub abc}{sup (2)}(ω) represents the second order nonlinear optical susceptibilities, possess six non-zero components in this symmetry (tetragonal), called: 1 2 3, 2 1 3, 2 3 1, 1 3 2, 3 1 2 and 3 2 1

  5. Luminescence and charge trapping in Cs.sub.2./sub.HfCl.sub.6./sub. single crystals: optical and magnetic resonance spectroscopy study

    Czech Academy of Sciences Publication Activity Database

    Král, Robert; Babin, Vladimir; Mihóková, Eva; Buryi, Maksym; Laguta, Valentyn; Nitsch, Karel; Nikl, Martin

    2017-01-01

    Roč. 121, č. 22 (2017), s. 12375-12382 ISSN 1932-7447 R&D Projects: GA MŠk LO1409; GA ČR GA17-09933S Institutional support: RVO:68378271 Keywords : Cs2HfCl6 * single crystal * luminescence * temperature dependence * EPR spectroscopy Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 4.536, year: 2016

  6. Measurement of the single top quark production cross section and |Vtb| in events with one charged lepton, large missing transverse energy, and jets at CDF.

    Science.gov (United States)

    Aaltonen, T; Amerio, S; Amidei, D; Anastassov, A; Annovi, A; Antos, J; Apollinari, G; Appel, J A; Arisawa, T; Artikov, A; Asaadi, J; Ashmanskas, W; Auerbach, B; Aurisano, A; Azfar, F; Badgett, W; Bae, T; Barbaro-Galtieri, A; Barnes, V E; Barnett, B A; Barria, P; Bartos, P; Bauce, M; Bedeschi, F; Behari, S; Bellettini, G; Bellinger, J; Benjamin, D; Beretvas, A; Bhatti, A; Bland, K R; Blumenfeld, B; Bocci, A; Bodek, A; Bortoletto, D; Boudreau, J; Boveia, A; Brigliadori, L; Bromberg, C; Brucken, E; Budagov, J; Budd, H S; Burkett, K; Busetto, G; Bussey, P; Butti, P; Buzatu, A; Calamba, A; Camarda, S; Campanelli, M; Canelli, F; Carls, B; Carlsmith, D; Carosi, R; Carrillo, S; Casal, B; Casarsa, M; Castro, A; Catastini, P; Cauz, D; Cavaliere, V; Cerri, A; Cerrito, L; Chen, Y C; Chertok, M; Chiarelli, G; Chlachidze, G; Cho, K; Chokheli, D; Clark, A; Clarke, C; Convery, M E; Conway, J; Corbo, M; Cordelli, M; Cox, C A; Cox, D J; Cremonesi, M; Cruz, D; Cuevas, J; Culbertson, R; d'Ascenzo, N; Datta, M; de Barbaro, P; Demortier, L; Deninno, M; D'Errico, M; Devoto, F; Di Canto, A; Di Ruzza, B; Dittmann, J R; Donati, S; D'Onofrio, M; Dorigo, M; Driutti, A; Ebina, K; Edgar, R; Elagin, A; Erbacher, R; Errede, S; Esham, B; Farrington, S; Fernández Ramos, J P; Field, R; Flanagan, G; Forrest, R; Franklin, M; Freeman, J C; Frisch, H; Funakoshi, Y; Galloni, C; Garfinkel, A F; Garosi, P; Gerberich, H; Gerchtein, E; Giagu, S; Giakoumopoulou, V; Gibson, K; Ginsburg, C M; Giokaris, N; Giromini, P; Glagolev, V; Glenzinski, D; Gold, M; Goldin, D; Golossanov, A; Gomez, G; Gomez-Ceballos, G; Goncharov, M; González López, O; Gorelov, I; Goshaw, A T; Goulianos, K; Gramellini, E; Grosso-Pilcher, C; Group, R C; Guimaraes da Costa, J; Hahn, S R; Han, J Y; Happacher, F; Hara, K; Hare, M; Harr, R F; Harrington-Taber, T; Hatakeyama, K; Hays, C; Heinrich, J; Herndon, M; Hirschbuehl, D; Hocker, A; Hong, Z; Hopkins, W; Hou, S; Hughes, R E; Husemann, U; Hussein, M; Huston, J; Introzzi, G; Iori, M; Ivanov, A; James, E; Jang, D; Jayatilaka, B; Jeon, E J; Jindariani, S; Jones, M; Joo, K K; Jun, S Y; Junk, T R; Kambeitz, M; Kamon, T; Karchin, P E; Kasmi, A; Kato, Y; Ketchum, W; Keung, J; Kilminster, B; Kim, D H; Kim, H S; Kim, J E; Kim, M J; Kim, S H; Kim, S B; Kim, Y J; Kim, Y K; Kimura, N; Kirby, M; Knoepfel, K; Kondo, K; Kong, D J; Konigsberg, J; Kotwal, A V; Kreps, M; Kroll, J; Kruse, M; Kuhr, T; Kurata, M; Laasanen, A T; Lammel, S; Lancaster, M; Lannon, K; Latino, G; Lee, H S; Lee, J S; Leo, S; Leone, S; Lewis, J D; Limosani, A; Lipeles, E; Lister, A; Liu, H; Liu, Q; Liu, T; Lockwitz, S; Loginov, A; Lucchesi, D; Lucà, A; Lueck, J; Lujan, P; Lukens, P; Lungu, G; Lys, J; Lysak, R; Madrak, R; Maestro, P; Malik, S; Manca, G; Manousakis-Katsikakis, A; Marchese, L; Margaroli, F; Marino, P; Matera, K; Mattson, M E; Mazzacane, A; Mazzanti, P; McNulty, R; Mehta, A; Mehtala, P; Mesropian, C; Miao, T; Mietlicki, D; Mitra, A; Miyake, H; Moed, S; Moggi, N; Moon, C S; Moore, R; Morello, M J; Mukherjee, A; Muller, Th; Murat, P; Mussini, M; Nachtman, J; Nagai, Y; Naganoma, J; Nakano, I; Napier, A; Nett, J; Neu, C; Nigmanov, T; Nodulman, L; Noh, S Y; Norniella, O; Oakes, L; Oh, S H; Oh, Y D; Oksuzian, I; Okusawa, T; Orava, R; Ortolan, L; Pagliarone, C; Palencia, E; Palni, P; Papadimitriou, V; Parker, W; Pauletta, G; Paulini, M; Paus, C; Phillips, T J; Pianori, E; Pilot, J; Pitts, K; Plager, C; Pondrom, L; Poprocki, S; Potamianos, K; Pranko, A; Prokoshin, F; Ptohos, F; Punzi, G; Redondo Fernández, I; Renton, P; Rescigno, M; Rimondi, F; Ristori, L; Robson, A; Rodriguez, T; Rolli, S; Ronzani, M; Roser, R; Rosner, J L; Ruffini, F; Ruiz, A; Russ, J; Rusu, V; Sakumoto, W K; Sakurai, Y; Santi, L; Sato, K; Saveliev, V; Savoy-Navarro, A; Schlabach, P; Schmidt, E E; Schwarz, T; Scodellaro, L; Scuri, F; Seidel, S; Seiya, Y; Semenov, A; Sforza, F; Shalhout, S Z; Shears, T; Shepard, P F; Shimojima, M; Shochet, M; Shreyber-Tecker, I; Simonenko, A; Sliwa, K; Smith, J R; Snider, F D; Song, H; Sorin, V; St Denis, R; Stancari, M; Stentz, D; Strologas, J; Sudo, Y; Sukhanov, A; Suslov, I; Takemasa, K; Takeuchi, Y; Tang, J; Tecchio, M; Teng, P K; Thom, J; Thomson, E; Thukral, V; Toback, D; Tokar, S; Tollefson, K; Tomura, T; Tonelli, D; Torre, S; Torretta, D; Totaro, P; Trovato, M; Ukegawa, F; Uozumi, S; Vázquez, F; Velev, G; Vellidis, C; Vernieri, C; Vidal, M; Vilar, R; Vizán, J; Vogel, M; Volpi, G; Wagner, P; Wallny, R; Wang, S M; Waters, D; Wester, W C; Whiteson, D; Wicklund, A B; Wilbur, S; Williams, H H; Wilson, J S; Wilson, P; Winer, B L; Wittich, P; Wolbers, S; Wolfe, H; Wright, T; Wu, X; Wu, Z; Yamamoto, K; Yamato, D; Yang, T; Yang, U K; Yang, Y C; Yao, W-M; Yeh, G P; Yi, K; Yoh, J; Yorita, K; Yoshida, T; Yu, G B; Yu, I; Zanetti, A M; Zeng, Y; Zhou, C; Zucchelli, S

    2014-12-31

    We report a measurement of single top quark production in proton-antiproton collisions at a center-of-mass energy of sqrt[s]=1.96  TeV using a data set corresponding to 7.5  fb(-1) of integrated luminosity collected by the Collider Detector at Fermilab. We select events consistent with the single top quark decay process t→Wb→ℓνb by requiring the presence of an electron or muon, a large imbalance of transverse momentum indicating the presence of a neutrino, and two or three jets including at least one originating from a bottom quark. An artificial neural network is used to discriminate the signal from backgrounds. We measure a single top quark production cross section of 3.04(-0.53)(+0.57)  pb and set a lower limit on the magnitude of the coupling between the top quark and bottom quark |Vtb|>0.78 at the 95% credibility level.

  7. The role of radiative de-excitation in the neutralization process of highly charged ions interacting with a single layer of graphene

    Science.gov (United States)

    Schwestka, J.; Wilhelm, R. A.; Gruber, E.; Heller, R.; Kozubek, R.; Schleberger, M.; Facsko, S.; Aumayr, F.

    2018-05-01

    X-ray emission of slow (graphene. To discriminate against X-ray emission originating from the graphene's support grid a coincidence technique is used. X-ray emission of 75 keV Ar17+ and Ar18+ ions with either one or two K-shell vacancies is recorded. Using a windowless Bruker XFlash detector allows us to measure additionally Ar KLL and KLM Auger electrons and determine the branching ratio of radiative vs. non-radiative decay of Ar K-shell holes. Furthermore, X-ray spectra for 100 keV Xe22+-Xe35+ ions are compared, showing a broad M-line peak for all cases, where M-shell vacancies are present. All these peaks are accompanied by emission lines at still higher energies indicating the presence of a hollow atom during X-ray decay. We report a linear shift of the main M-line peak to higher energies for increasing incident charge state, i.e. increasing number of M-shell holes.

  8. The chemistry of nicotinamide adenine dinucleotide (NAD) analogues containing C-nucleosides related to nicotinamide riboside.

    Science.gov (United States)

    Pankiewicz, Krzysztof W; Watanabe, Kyoichi A; Lesiak-Watanabe, Krystyna; Goldstein, Barry M; Jayaram, Hiremagalur N

    2002-04-01

    Oncolytic C-nucleosides, tiazofurin (2-beta-D-ribofuranosylthiazole-4-carboxamide) and benzamide riboside (3-beta-D-ribofuranosylbenzamide) are converted in cell into active metabolites thiazole-4-carboxamide- and benzamide adenine dinucleotide, TAD and BAD, respectively. TAD and BAD as NAD analogues were found to bind at the nicotinamide adenine dinucleotide (cofactor NAD) site of inosine monophosphate dehydrogenase (IMPDH), an important target in cancer treatment. The synthesis and evaluation of anticancer activity of a number of C-nucleosides related to tiazofurin and nicotinamide riboside then followed and are reviewed herein. Interestingly, pyridine C-nucleosides (such as C-nicotinamide riboside) are not metabolized into the corresponding NAD analogues in cell. Their conversion by chemical methods is described. As dinucleotides these compounds show inhibition of IMPDH in low micromolar level. Also, the synthesis of BAD in metabolically stable bis(phosphonate) form is discussed indicating the usefulness of such preformed inhibitors in drug development. Among tiazofurin analogues, Franchetti and Grifantini found, that the replacement of the sulfur by oxygen (as in oxazafurin) but not the removal of nitrogen (tiophenfurin) of the thiazole ring resulted in inactive compounds. The anti cancer activity of their synthetic dinucleotide analogues indicate that inactive compounds are not only poorly metabolized in cell but also are weak inhibitors of IMPDH as dinucleotides.

  9. Direct Visualization of Asymmetric Adenine Nucleotide-Induced Conformational Changes in MutLα

    Science.gov (United States)

    Sacho, Elizabeth J; Kadyrov, Farid A; Modrich, Paul; Kunkel, Thomas A; Erie, Dorothy A

    2010-01-01

    Summary MutLα, the heterodimeric eukaryotic MutL homolog, is required for DNA mismatch repair (MMR) in vivo. It has been suggested that conformational changes, modulated by adenine nucleotides, mediate the interactions of MutLα with other proteins in the MMR pathway, coordinating the recognition of DNA mismatches by MutSα and the activation of MutLα with the downstream events that lead to repair. Thus far, the only evidence for these conformational changes has come from x-ray crystallography of isolated domains, indirect biochemical analyses, and comparison to other members of the GHL ATPase family to which MutLα belongs. Using atomic force microscopy (AFM), coupled with biochemical techniques, we demonstrate that adenine nucleotides induce large asymmetric conformational changes in full-length yeast and human MutLα, and that these changes are associated with significant increases in secondary structure. These data reveal an ATPase cycle where sequential nucleotide binding, hydrolysis, and release modulate the conformational states of MutLα. PMID:18206974

  10. Role of Hydrogen Bonding in the Formation of Adenine Chains on Cu(110 Surfaces

    Directory of Open Access Journals (Sweden)

    Lanxia Cheng

    2016-12-01

    Full Text Available Understanding the adsorption properties of DNA bases on metal surfaces is fundamental for the rational control of surface functionalization leading to the realisation of biocompatible devices for biosensing applications, such as monitoring of particular parameters within bio-organic environments and drug delivery. In this study, the effects of deposition rate and substrate temperature on the adsorption behavior of adenine on Cu(110 surfaces have been investigated using scanning tunneling microscopy (STM and density functional theory (DFT modeling, with a focus on the characterization of the morphology of the adsorbed layers. STM results revealed the formation of one-dimensional linear chains and ladder-like chains parallel to the [110] direction, when dosing at a low deposition rate at room temperature, followed by annealing to 490 K. Two mirror related, well-ordered chiral domains oriented at ±55° with respect to the [110] direction are formed upon deposition on a substrate kept at 490 K. The molecular structures observed via STM are rationalized and qualitatively described on the basis of the DFT modeling. The observation of a variety of ad-layer structures influenced by deposition rate and substrate temperature indicates that dynamic processes and hydrogen bonding play an important role in the self-assembly of adenine on the Cu(110 surface.

  11. Microwave-assisted stereospecific synthesis of novel tetrahydropyran adenine isonucleosides and crystal structures determination

    Science.gov (United States)

    Silva, Fábio P. L.; Cirqueira, Marilia L.; Martins, Felipe T.; Vasconcellos, Mário L. A. A.

    2013-11-01

    We describe in this article stereospecific syntheses for new isonucleosides analogs of adenine 5-7 from tosyl derivatives 2-4 accessing by microwave irradiations (50-80%). The adenine reacts entirely at the N(9) position. Compounds 2-4 were prepared in two steps from the corresponding alcohols 1, 8 and 9 (81-92%). These tetrahydropyrans alcohols 1, 8 and 9 are achiral (Meso compounds) and were prepared in two steps with complete control of 2,4,6-cis relative configuration by Prins cyclization reaction (60-63%) preceded by the Barbier reaction between allyl bromide with benzaldehyde, 4-fluorobenzaldehyde and 2-naphthaldehyde respectively under Lewis acid conditions (96-98%). The configurations and preferential conformations of 5-7 were determined by crystal structure of 6. These novel isonucleosides 5-7 present in silico potentiality to act as GPCR ligand, kinase inhibitor and enzyme inhibitor, evaluated by Molinspiration program, consistent with the expected antiviral and anticancer bioactivities.

  12. DNA adenine methylation modulates pathogenicity of Klebsiella pneumoniae genotype K1.

    Science.gov (United States)

    Fang, Chi-Tai; Yi, Wen-Ching; Shun, Chia-Tung; Tsai, Shih-Feng

    2017-08-01

    Klebsiella pneumoniae genotype K1 is a highly virulent pathogen that causes liver abscess and metastatic endophthalmitis/meningitis. Whether its pathogenicity is controlled by DNA adenine methylase (Dam), an epigenetic regulator of bacterial virulence gene expression, is yet unknown. We aimed to study the role of DNA adenine methylation in the pathogenicity of K. pneumoniae genotype K1. We identified the dam gene in the prototype tissue-invasive strain (NTUH-K2044) of K. pneumoniae genotype K1, using the strain's complete genome sequence in GenBank. We constructed a dam - mutant and compared it with the wild type, in terms of in vitro serum resistance and in vivo BALB/cByl mice inoculation. Loss of Dam activity in the mutant was verified by MboI restriction digestion of the genomic DNA and a 1000-fold increase in spontaneous mutation rate. The dam mutant lost at least 68% of serum resistance when compared with the wild type (survival ratio at 1 hour: 2.6 ± 0.4 vs. 8.2 ± 1.9; at 2 hours: 3.9 ± 1.6 vs. 17.4 ± 3.6; p values pneumoniae genotype K1. The incomplete attenuation indicates the existence of other regulatory factors. Copyright © 2015. Published by Elsevier B.V.

  13. Influence of the Resonant Electronic Transition on the Intensity of the Raman Radial Breathing Mode of Single Walled Carbon Nanotubes during Electrochemical Charging

    Czech Academy of Sciences Publication Activity Database

    Kalbáč, Martin; Kavan, Ladislav

    2009-01-01

    Roč. 113, č. 37 (2009), s. 16408-16413 ISSN 1932-7447 R&D Projects: GA ČR GC203/07/J067; GA AV ČR IAA400400911; GA AV ČR IAA400400804; GA AV ČR KAN200100801; GA MŠk LC510 Institutional research plan: CEZ:AV0Z40400503 Keywords : single-walled carbon nanotubes * radial breathing mode * electrochemistry Subject RIV: CG - Electrochemistry Impact factor: 4.224, year: 2009

  14. Azimuthal transverse single-spin asymmetries of inclusive jets and charged pions within jets from polarized-proton collisions at √{s }=500 GeV

    Science.gov (United States)

    Adamczyk, L.; Adams, J. R.; Adkins, J. K.; Agakishiev, G.; Aggarwal, M. M.; Ahammed, Z.; Ajitanand, N. N.; Alekseev, I.; Anderson, D. M.; Aoyama, R.; Aparin, A.; Arkhipkin, D.; Aschenauer, E. C.; Ashraf, M. U.; Attri, A.; Averichev, G. S.; Bai, X.; Bairathi, V.; Barish, K.; Behera, A.; Bellwied, R.; Bhasin, A.; Bhati, A. K.; Bhattarai, P.; Bielcik, J.; Bielcikova, J.; Bland, L. C.; Bordyuzhin, I. G.; Bouchet, J.; Brandenburg, J. D.; Brandin, A. V.; Brown, D.; Bryslawskyj, J.; Bunzarov, I.; Butterworth, J.; Caines, H.; Calderón de la Barca Sánchez, M.; Campbell, J. M.; Cebra, D.; Chakaberia, I.; Chaloupka, P.; Chang, Z.; Chankova-Bunzarova, N.; Chatterjee, A.; Chattopadhyay, S.; Chen, X.; Chen, X.; Chen, J. H.; Cheng, J.; Cherney, M.; Christie, W.; Contin, G.; Crawford, H. J.; Das, S.; Dedovich, T. G.; Deng, J.; Deppner, I. M.; Derevschikov, A. A.; Didenko, L.; Dilks, C.; Dong, X.; Drachenberg, J. L.; Draper, J. E.; Dunlop, J. C.; Efimov, L. G.; Elsey, N.; Engelage, J.; Eppley, G.; Esha, R.; Esumi, S.; Evdokimov, O.; Ewigleben, J.; Eyser, O.; Fatemi, R.; Fazio, S.; Federic, P.; Federicova, P.; Fedorisin, J.; Feng, Z.; Filip, P.; Finch, E.; Fisyak, Y.; Flores, C. E.; Fujita, J.; Fulek, L.; Gagliardi, C. A.; Geurts, F.; Gibson, A.; Girard, M.; Grosnick, D.; Gunarathne, D. S.; Guo, Y.; Gupta, A.; Guryn, W.; Hamad, A. I.; Hamed, A.; Harlenderova, A.; Harris, J. W.; He, L.; Heppelmann, S.; Heppelmann, S.; Herrmann, N.; Hirsch, A.; Horvat, S.; Huang, B.; Huang, T.; Huang, X.; Huang, H. Z.; Humanic, T. J.; Huo, P.; Igo, G.; Jacobs, W. W.; Jentsch, A.; Jia, J.; Jiang, K.; Jowzaee, S.; Judd, E. G.; Kabana, S.; Kalinkin, D.; Kang, K.; Kapukchyan, D.; Kauder, K.; Ke, H. W.; Keane, D.; Kechechyan, A.; Khan, Z.; Kikoła, D. P.; Kim, C.; Kisel, I.; Kisiel, A.; Kochenda, L.; Kocmanek, M.; Kollegger, T.; Kosarzewski, L. K.; Kraishan, A. F.; Krauth, L.; Kravtsov, P.; Krueger, K.; Kulathunga, N.; Kumar, L.; Kvapil, J.; Kwasizur, J. H.; Lacey, R.; Landgraf, J. M.; Landry, K. D.; Lauret, J.; Lebedev, A.; Lednicky, R.; Lee, J. H.; Li, X.; Li, W.; Li, Y.; Li, C.; Lidrych, J.; Lin, T.; Lisa, M. A.; Liu, F.; Liu, P.; Liu, Y.; Liu, H.; Ljubicic, T.; Llope, W. J.; Lomnitz, M.; Longacre, R. S.; Luo, X.; Luo, S.; Ma, G. L.; Ma, L.; Ma, R.; Ma, Y. G.; Magdy, N.; Majka, R.; Mallick, D.; Margetis, S.; Markert, C.; Matis, H. S.; Mayes, D.; Meehan, K.; Mei, J. C.; Miller, Z. W.; Minaev, N. G.; Mioduszewski, S.; Mishra, D.; Mizuno, S.; Mohanty, B.; Mondal, M. M.; Morozov, D. A.; Mustafa, M. K.; Nasim, Md.; Nayak, T. K.; Nelson, J. M.; Nemes, D. B.; Nie, M.; Nigmatkulov, G.; Niida, T.; Nogach, L. V.; Nonaka, T.; Nurushev, S. B.; Odyniec, G.; Ogawa, A.; Oh, K.; Okorokov, V. A.; Olvitt, D.; Page, B. S.; Pak, R.; Pandit, Y.; Panebratsev, Y.; Pawlik, B.; Pei, H.; Perkins, C.; Pluta, J.; Poniatowska, K.; Porter, J.; Posik, M.; Pruthi, N. K.; Przybycien, M.; Putschke, J.; Quintero, A.; Ramachandran, S.; Ray, R. L.; Reed, R.; Rehbein, M. J.; Ritter, H. G.; Roberts, J. B.; Rogachevskiy, O. V.; Romero, J. L.; Roth, J. D.; Ruan, L.; Rusnak, J.; Rusnakova, O.; Sahoo, N. R.; Sahu, P. K.; Salur, S.; Sandweiss, J.; Saur, M.; Schambach, J.; Schmah, A. M.; Schmidke, W. B.; Schmitz, N.; Schweid, B. R.; Seger, J.; Sergeeva, M.; Seto, R.; Seyboth, P.; Shah, N.; Shahaliev, E.; Shanmuganathan, P. V.; Shao, M.; Shen, W. Q.; Shi, S. S.; Shi, Z.; Shou, Q. Y.; Sichtermann, E. P.; Sikora, R.; Simko, M.; Singha, S.; Skoby, M. J.; Smirnov, N.; Smirnov, D.; Solyst, W.; Sorensen, P.; Spinka, H. M.; Srivastava, B.; Stanislaus, T. D. S.; Stewart, D. J.; Strikhanov, M.; Stringfellow, B.; Suaide, A. A. P.; Sugiura, T.; Sumbera, M.; Summa, B.; Sun, Y.; Sun, X.; Sun, X. M.; Surrow, B.; Svirida, D. N.; Tang, A. H.; Tang, Z.; Taranenko, A.; Tarnowsky, T.; Tawfik, A.; Thäder, J.; Thomas, J. H.; Timmins, A. R.; Tlusty, D.; Todoroki, T.; Tokarev, M.; Trentalange, S.; Tribble, R. E.; Tribedy, P.; Tripathy, S. K.; Trzeciak, B. A.; Tsai, O. D.; Ullrich, T.; Underwood, D. G.; Upsal, I.; Van Buren, G.; van Nieuwenhuizen, G.; Vasiliev, A. N.; Videbæk, F.; Vokal, S.; Voloshin, S. A.; Vossen, A.; Wang, G.; Wang, Y.; Wang, F.; Wang, Y.; Webb, G.; Webb, J. C.; Wen, L.; Westfall, G. D.; Wieman, H.; Wissink, S. W.; Witt, R.; Wu, Y.; Xiao, Z. G.; Xie, G.; Xie, W.; Xu, Y. F.; Xu, J.; Xu, Q. H.; Xu, N.; Xu, Z.; Yang, S.; Yang, Y.; Yang, C.; Yang, Q.; Ye, Z.; Ye, Z.; Yi, L.; Yip, K.; Yoo, I.-K.; Yu, N.; Zbroszczyk, H.; Zha, W.; Zhang, Z.; Zhang, J.; Zhang, S.; Zhang, S.; Zhang, J.; Zhang, Y.; Zhang, X. P.; Zhang, J. B.; Zhao, J.; Zhong, C.; Zhou, L.; Zhou, C.; Zhu, X.; Zhu, Z.; Zyzak, M.; STAR Collaboration

    2018-02-01

    We report the first measurements of transverse single-spin asymmetries for inclusive jet and jet+π± production at midrapidity from transversely polarized proton-proton collisions at √{s }=500 GeV . The data were collected in 2011 with the STAR detector sampled from 23 pb-1 integrated luminosity with an average beam polarization of 53%. Asymmetries are reported for jets with transverse momenta 6 single-spin asymmetry, sensitive to twist-3 initial-state quark-gluon correlators; the Collins asymmetry, sensitive to quark transversity coupled to the polarized Collins fragmentation function; and the first measurement of the "Collins-like" asymmetry, sensitive to linearly polarized gluons. Within the present statistical precision, inclusive-jet and Collins-like asymmetries are small, with the latter allowing the first experimental constraints on gluon linear polarization in a polarized proton. At higher values of jet transverse momenta, we observe the first nonzero Collins asymmetries in polarized-proton collisions, with a statistical significance of greater than 5 σ . The results span a range of x similar to results from semi-inclusive deep-inelastic scattering but at much higher Q2. The Collins results enable tests of universality and factorization breaking in the transverse momentum-dependent formulation of perturbative quantum chromodynamics.

  15. On the existence of the H3 tautomer of adenine in aqueous solution. Rationalizations based on hybrid quantum mechanics/molecular mechanics predictions

    DEFF Research Database (Denmark)

    Aidas, Kestutis; Mikkelsen, Kurt V; Kongsted, Jacob

    2010-01-01

    The (15)N NMR spectrum of adenine in aqueous solution has been modeled using high-level combined density functional theory/molecular mechanics techniques coupled to a dynamical averaging scheme. The explicit consideration of the three lowest-energy tautomers of adenine-H9, H7 and H3-allows for a ...

  16. Modeling the high-energy electronic state manifold of adenine: Calibration for nonlinear electronic spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Nenov, Artur, E-mail: Artur.Nenov@unibo.it; Giussani, Angelo; Segarra-Martí, Javier; Jaiswal, Vishal K. [Dipartimento di Chimica “G. Ciamician,” Università di Bologna, Via Selmi 2, IT-40126 Bologna (Italy); Rivalta, Ivan [Université de Lyon, CNRS, Institut de Chimie de Lyon, École Normale Supérieure de Lyon, 46 Allée d’Italie, F-69364 Lyon Cedex 07 (France); Cerullo, Giulio [Dipartimento di Fisica, Politecnico di Milano, IFN-CNR, Piazza Leonardo Da Vinci 32, IT-20133 Milano (Italy); Mukamel, Shaul [Department of Chemistry, University of California, Irvine, California 92697-2025 (United States); Garavelli, Marco, E-mail: marco.garavelli@unibo.it, E-mail: marco.garavelli@ens-lyon.fr [Dipartimento di Chimica “G. Ciamician,” Università di Bologna, Via Selmi 2, IT-40126 Bologna (Italy); Université de Lyon, CNRS, Institut de Chimie de Lyon, École Normale Supérieure de Lyon, 46 Allée d’Italie, F-69364 Lyon Cedex 07 (France)

    2015-06-07

    Pump-probe electronic spectroscopy using femtosecond laser pulses has evolved into a standard tool for tracking ultrafast excited state dynamics. Its two-dimensional (2D) counterpart is becoming an increasingly available and promising technique for resolving many of the limitations of pump-probe caused by spectral congestion. The ability to simulate pump-probe and 2D spectra from ab initio computations would allow one to link mechanistic observables like molecular motions and the making/breaking of chemical bonds to experimental observables like excited state lifetimes and quantum yields. From a theoretical standpoint, the characterization of the electronic transitions in the visible (Vis)/ultraviolet (UV), which are excited via the interaction of a molecular system with the incoming pump/probe pulses, translates into the determination of a computationally challenging number of excited states (going over 100) even for small/medium sized systems. A protocol is therefore required to evaluate the fluctuations of spectral properties like transition energies and dipole moments as a function of the computational parameters and to estimate the effect of these fluctuations on the transient spectral appearance. In the present contribution such a protocol is presented within the framework of complete and restricted active space self-consistent field theory and its second-order perturbation theory extensions. The electronic excited states of adenine have been carefully characterized through a previously presented computational recipe [Nenov et al., Comput. Theor. Chem. 1040–1041, 295-303 (2014)]. A wise reduction of the level of theory has then been performed in order to obtain a computationally less demanding approach that is still able to reproduce the characteristic features of the reference data. Foreseeing the potentiality of 2D electronic spectroscopy to track polynucleotide ground and excited state dynamics, and in particular its expected ability to provide

  17. Modeling the high-energy electronic state manifold of adenine: Calibration for nonlinear electronic spectroscopy

    Science.gov (United States)

    Nenov, Artur; Giussani, Angelo; Segarra-Martí, Javier; Jaiswal, Vishal K.; Rivalta, Ivan; Cerullo, Giulio; Mukamel, Shaul; Garavelli, Marco

    2015-06-01

    Pump-probe electronic spectroscopy using femtosecond laser pulses has evolved into a standard tool for tracking ultrafast excited state dynamics. Its two-dimensional (2D) counterpart is becoming an increasingly available and promising technique for resolving many of the limitations of pump-probe caused by spectral congestion. The ability to simulate pump-probe and 2D spectra from ab initio computations would allow one to link mechanistic observables like molecular motions and the making/breaking of chemical bonds to experimental observables like excited state lifetimes and quantum yields. From a theoretical standpoint, the characterization of the electronic transitions in the visible (Vis)/ultraviolet (UV), which are excited via the interaction of a molecular system with the incoming pump/probe pulses, translates into the determination of a computationally challenging number of excited states (going over 100) even for small/medium sized systems. A protocol is therefore required to evaluate the fluctuations of spectral properties like transition energies and dipole moments as a function of the computational parameters and to estimate the effect of these fluctuations on the transient spectral appearance. In the present contribution such a protocol is presented within the framework of complete and restricted active space self-consistent field theory and its second-order perturbation theory extensions. The electronic excited states of adenine have been carefully characterized through a previously presented computational recipe [Nenov et al., Comput. Theor. Chem. 1040-1041, 295-303 (2014)]. A wise reduction of the level of theory has then been performed in order to obtain a computationally less demanding approach that is still able to reproduce the characteristic features of the reference data. Foreseeing the potentiality of 2D electronic spectroscopy to track polynucleotide ground and excited state dynamics, and in particular its expected ability to provide

  18. Molecular dynamics simulations to examine structure, energetics, and evaporation/condensation dynamics in small charged clusters of water or methanol containing a single monatomic ion.

    Science.gov (United States)

    Daub, Christopher D; Cann, Natalie M

    2012-11-01

    We study small clusters of water or methanol containing a single Ca(2+), Na(+), or Cl(-) ion with classical molecular dynamics simulations, using models that incorporate polarizability via the Drude oscillator framework. Evaporation and condensation of solvent from these clusters is examined in two systems, (1) for isolated clusters initially prepared at different temperatures and (2) those with a surrounding inert (Ar) gas of varying temperature. We examine these clusters over a range of sizes, from almost bare ions up to 40 solvent molecules. We report data on the evaporation and condensation of solvent from the clusters and argue that the observed temperature dependence of evaporation in the smallest clusters demonstrates that the presence of heated gas alone cannot, in most cases, solely account for bare ion production in electrospray ionization (ESI), neglecting the key contribution of the electric field. We also present our findings on the structure and energetics of the clusters as a function of size. Our data agree well with the abundant literature on hydrated ion clusters and offer some novel insight into the structure of methanol and ion clusters, especially those with a Cl(-) anion, where we observe the presence of chain-like structures of methanol molecules. Finally, we provide some data on the reparameterizations necessary to simulate ions in methanol using the separately developed Drude oscillator models for methanol and for ions in water.

  19. Inner-shell spectroscopy and exchange interaction of Rydberg electrons bound by singly and doubly charged Kr and Xe atoms in small clusters

    Energy Technology Data Exchange (ETDEWEB)

    Nagasaka, Masanari; Hatsui, Takaki; Setoyama, Hiroyuki; Ruehl, Eckart [Institute for Molecular Science, Myodaiji, Okazaki 444-8585 (Japan); Kosugi, Nobuhiro, E-mail: kosugi@ims.ac.j [Institute for Molecular Science, Myodaiji, Okazaki 444-8585 (Japan)

    2011-01-15

    Surface-site resolved Kr 3d{sub 5/2}{sup -1}5p and 3d{sub 5/2}{sup -1}6p and Xe 4d{sub 5/2}{sup -1}6p and 4d{sub 5/2}{sup -1}7p Rydberg excited states in small van der Waals Kr and Xe clusters with a mean size of = 15 are investigated by X-ray absorption spectroscopy. Furthermore, surface-site resolved Kr 4s{sup -2}5p, 4s{sup -2}6p, and 4s{sup -1}4p{sup -1}5p shakeup-like Rydberg states in small Kr clusters are investigated by resonant Auger electron spectroscopy. The exchange interaction of the Rydberg electron with the surrounding atoms and the induced polarization of the surrounding atoms in the singly and doubly ionized atoms are deduced from the experimental spectra to analyze different surface-site contributions in small clusters, assuming that the corner, edge, face, and bulk sites have 3, 5-6, 8, and 12 nearest neighbor atoms. These energies are almost proportional to the number of the nearest neighbor atoms. The present analysis indicates that small Kr and Xe clusters with = 15 have an average or mixture structure between the fcc-like cubic and icosahedron-like spherical structures.

  20. Intramolecular stacking interactions in ternary copper(II) complexes formed by a heteroaromatic amine and 9-[2-(2-phosphonoethoxy)ethyl]adenine, a relative of the antiviral nucleotide analogue 9-[2-(phosphonomethoxy)ethyl]adenine

    Czech Academy of Sciences Publication Activity Database

    Fernández-Botello, A.; Holý, Antonín; Moreno, V.; Sigel, H.

    2004-01-01

    Roč. 98, - (2004), s. 2114-2124 ISSN 0162-0134 R&D Projects: GA MŠk OC D20.002 Institutional research plan: CEZ:AV0Z4055905 Keywords : adenine nucleotide analogues * intramolecular equilibria * isomeric complexes Subject RIV: CC - Organic Chemistry Impact factor: 2.225, year: 2004

  1. Animal models of pediatric chronic kidney disease. Is adenine intake an appropriate model?

    Directory of Open Access Journals (Sweden)

    Débora Claramunt

    2015-11-01

    Full Text Available Pediatric chronic kidney disease (CKD has peculiar features. In particular, growth impairment is a major clinical manifestation of CKD that debuts in pediatric age because it presents in a large proportion of infants and children with CKD and has a profound impact on the self-esteem and social integration of the stunted patients. Several factors associated with CKD may lead to growth retardation by interfering with the normal physiology of growth plate, the organ where longitudinal growth rate takes place. The study of growth plate is hardly possible in humans and justifies the use of animal models. Young rats made uremic by 5/6 nephrectomy have been widely used as a model to investigate growth retardation in CKD. This article examines the characteristics of this model and analyzes the utilization of CKD induced by high adenine diet as an alternative research protocol.

  2. Structural study and investigation of NMR tensors in interaction of dopamine with Adenine and guanine

    Directory of Open Access Journals (Sweden)

    Lingjia Xu

    2007-04-01

    Full Text Available The interaction of dopamine with adenine and guanine were studied at the Hartree-Fock level theory. The structural and vibrational properties of dopamine-4-N7GUA and dopamine-4-N3ADE were studied at level of HF/6-31G*. Interaction energies (ΔE were calculated to be -11.49 and -11.92 kcal/mol, respectively. Some of bond lengths, angels and tortions are compared. NBO studies were performed to the second-order and perturbative estimates of donor-acceptor interaction have been done. The procedures of gauge-invariant atomic orbital (GIAO and continuous-set-of-gauge-transformation (CSGT were employed to calculate isotropic shielding, chemical shifts anisotropy and chemical shifts anisotropy asymmetry and effective anisotropy using 6-31G* basis set. These calculations yielded molecular geometries in good agreement with available experimental data.

  3. Metal-adeninate vertices for the construction of an exceptionally porous metal-organic framework.

    Science.gov (United States)

    An, Jihyun; Farha, Omar K; Hupp, Joseph T; Pohl, Ehmke; Yeh, Joanne I; Rosi, Nathaniel L

    2012-01-03

    Metal-organic frameworks comprising metal-carboxylate cluster vertices and long, branched organic linkers are the most porous materials known, and therefore have attracted tremendous attention for many applications, including gas storage, separations, catalysis and drug delivery. To increase metal-organic framework porosity, the size and complexity of linkers has increased. Here we present a promising alternative strategy for constructing mesoporous metal-organic frameworks that addresses the size of the vertex rather than the length of the organic linker. This approach uses large metal-biomolecule clusters, in particular zinc-adeninate building units, as vertices to construct bio-MOF-100, an exclusively mesoporous metal-organic framework. Bio-MOF-100 exhibits a high surface area (4,300 m(2) g(-1)), one of the lowest crystal densities (0.302 g cm(-3)) and the largest metal-organic framework pore volume reported to date (4.3 cm(3) g(-1)).

  4. Synthesis and enzymatic incorporation of α-L-threofuranosyl adenine triphosphate (tATP).

    Science.gov (United States)

    Zhang, Su; Chaput, John C

    2013-03-01

    Threose nucleic acid (TNA) is an artificial genetic polymer in which the natural ribose sugar found in RNA has been replaced with an unnatural threose sugar. TNA can be synthesized enzymatically using Therminator DNA polymerase to copy DNA templates into TNA. Here, we expand the substrate repertoire of Therminator DNA polymerase to include threofuranosyl adenine 3'-triphsophate (tATP). We chemically synthesized tATP by two different methods from the 2'-O-acetyl derivative. Enzyme-mediated polymerization reveals that tATP functions as an efficient substrate for Therminator DNA polymerase, indicating that tATP can replace the diaminopurine analogue (tDTP) in TNA transcription reactions. Copyright © 2012 Elsevier Ltd. All rights reserved.

  5. Conducting polymer and its composite materials based electrochemical sensor for Nicotinamide Adenine Dinucleotide (NADH).

    Science.gov (United States)

    Omar, Fatin Saiha; Duraisamy, Navaneethan; Ramesh, K; Ramesh, S

    2016-05-15

    Nicotinamide Adenine Dinucleotide (NADH) is an important coenzyme in the human body that participates in many metabolic reactions. The impact of abnormal concentrations of NADH significantly causes different diseases in human body. Electrochemical detection of NADH using bare electrode is a challenging task especially in the presence of main electroactive interferences such as ascorbic acid (AA), uric acid (UA) and dopamine (DA). Modified electrodes have been widely explored to overcome the problems of poor sensitivity and selectivity occurred from bare electrodes. This review gives an overview on the progress of using conducting polymers, polyelectrolyte and its composites (co-polymer, carbonaceous, metal, metal oxide and clay) based modified electrodes for the sensing of NADH. In addition, developments on the fabrication of numerous conducting polymer composites based modified electrodes are clearly described. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. Isotope effect studies of the chemical mechanism of nicotinamide adenine dinucleotide malic enzyme from Crassula

    International Nuclear Information System (INIS)

    Grissom, C.B.; Willeford, O.; Wedding, R.T.

    1987-01-01

    The 13 C primary kinetic isotope effect on the decarboxylation of malate by nicotinamide adenine dinucleotide malic enzyme from Crassula argentea is 1.0199 +/- 0.0006 with proteo L-malate-2-H and 1.0162 +/- 0.0003 with malate-2-d. The primary deuterium isotope effect is 1.45 +/- 0.10 on V/K and 1.93 +/- 0.13 on V/sub max/. This indicates a stepwise conversion of malate to pyruvate and CO 2 with hydride transfer preceding decarboxylation, thereby suggesting a discrete oxaloacetate intermediate. This is in agreement with the stepwise nature of the chemical mechanism of other malic enzymes despite the Crassula enzyme's inability to reduce or decarboxylate oxaloacetate. Differences in morphology and allosteric regulation between enzymes suggest specialization of the Crassula malic enzyme for the physiology of crassulacean and acid metabolism while maintaining the catalytic events founds in malic enzymes from animal sources

  7. Environmental charges in airline markets

    Energy Technology Data Exchange (ETDEWEB)

    Carlsson, Fredrik [Goeteborg Univ., Dept. of Economics, Goeteborg (Sweden)

    2002-07-01

    Over the last two decades many airline markets have been deregulated, resulting in increased competition and use of different types of networks. At the same time there has been an intense discussion on environmental taxation of airline traffic. It is likely that an optimal environmental charge and the effects of a charge differ between different types of aviation markets. In this paper, we derive optimal flight (environmental) charges for different types of airline markets. The first type of market is a multiproduct monopoly airline operating either a point-to-point network or a hub-and-spoke network. The optimal charge is shown to be similar in construction to an optimal charge for a monopolist. We also compare the environmental impact of the two types of networks. Given no differences in marginal damages between airports we find that an airline will always choose the network with the highest environmental damages. The second type of market we investigate is a multiproduct duopoly, where two airlines compete in both passengers and flights. The formulation of the optimal charge is similar to the optimal charge of a single product oligopoly. However, we also show that it is, because of strategic effects, difficult to determine the effects of the charge on the number of flights. (Author)

  8. Effect of adenine on bacterial translocation using technetium-99m labeled E. coli in an intestinal obstruction model in rats

    International Nuclear Information System (INIS)

    Ugur Oflaz; Fatma Yurt Lambrecht; Osman Yilmaz; Cetin Pekcetin

    2013-01-01

    This study aims to investigate effects of adenine on bacterial translocation (BT) using 99m Tc-labeled E. coli in an intestinal obstruction rat model. In the study twenty-one rats were used. The rats were divided into three groups according to different feeding patterns. The control group (CG) was fed with a standard chow diet for 7 days. Group A1 and group A2 were fed with adenine supplemented chow diet for 7 days. At the end of the feeding period, after all groups was submitted intestinal obstruction. 99m Tc-E. coli was injected into the rats' terminal ileum under anesthetic. The rats were sacrificed under aseptic conditions at 24th h after the surgery. The uptake of 99m Tc-E. coli was determined in organs such as the liver, mesenteric lymph nodes, spleen and ileum. Group A1 and group A2 results show that the uptake of 99m Tc-E. coli decreased in the blood and organs comparing to the CG. As a result, it was observed that adenine reduced the level of BT when compared with CG. The beneficial effect of adenine on BT in intestinal obstruction was observed. However, further studies are needed to more clearly assess how this benefit can be achieved. (author)

  9. The incorporation of 14C-adenine into the oocytes of Asellus aquaticus as studied by autoradiography

    NARCIS (Netherlands)

    Broek, C.J.H. van den; Tates, A.D.

    Asellus aquaticus females were injected with 8-14C-adenine, fixed after 3 hours and sectioned. In coated autoradiographs, the number of β-tracks from 14C were counted over nucleolus, nucleus and cytoplasm of the oocytes at various stages of their development. Incorporation into nucleolar RNA, being

  10. Nicotinamide adenine dinucleotide assisted shape-controlled synthesis of catalytically active raspberry-like gold nanostructures

    International Nuclear Information System (INIS)

    Das, Ashok Kumar; Layek, Rama K.; Kim, Nam Hoon; Samdani, Jitendra; Kang, Myung Chul; Lee, Joong Hee

    2015-01-01

    Graphical abstract: A facile method was developed for the synthesis of raspberry-like Au nanostructure and it was used as an electrocatalyst for the oxidation of methanol and reduction of oxygen. - Highlights: • Raspberry-like gold nanostructures have been synthesized. • Nicotinamide adenine dinucleotide plays an important role in the synthesis. • Raspberry-like Au nanostructure has an excellent electrocatalytic activity in methanol oxidation and oxygen reduction. - Abstract: We describe the shape-controlled growth of raspberry-like gold (Au) nanostructures and their application in the electrochemical oxidation of methanol and reduction of oxygen. Nicotinamide adenine dinucleotide (NAD + ) plays a vital role in the growth of raspberry-like Au nanostructures. The preferential adsorption of NAD + onto the (011) facets of Au favors the growth of raspberry-like morphology. In the absence of NAD + , icosahedral Au nanostructures were obtained. The raspberry-like Au nanostructures have been characterized by UV-visible spectroscopy, X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and electrochemical measurements. The FESEM image shows that the raspberry-like morphology has an average size of 170 nm. The spectral profile shows a broad band between 650 and 795 nm. Compared to Au nanoseeds and icosahedral Au nanostructures that were grown in the absence of NAD + , the raspberry-like morphology has excellent catalytic activity towards the electrochemical oxidation of methanol and reduction of oxygen. On the raspberry-like nanoparticle-based electrode, the oxidation of methanol was observed at 0.35 V in alkaline pH, and the reduction of oxygen was observed at -0.06 and -0.4 V in 0.1 M PBS. The electrochemical reduction of oxygen occurs in two steps: (i) reduction of oxygen to H 2 O 2 and (ii) further reduction of electrogenerated H 2 O 2 to water. The electrochemical performance of the raspberry-like nanostructure-based electrode is highly

  11. Lack of hepcidin ameliorates anemia and improves growth in an adenine-induced mouse model of chronic kidney disease.

    Science.gov (United States)

    Akchurin, Oleh; Sureshbabu, Angara; Doty, Steve B; Zhu, Yuan-Shan; Patino, Edwin; Cunningham-Rundles, Susanna; Choi, Mary E; Boskey, Adele; Rivella, Stefano

    2016-11-01

    Growth delay is common in children with chronic kidney disease (CKD), often associated with poor quality of life. The role of anemia in uremic growth delay is poorly understood. Here we describe an induction of uremic growth retardation by a 0.2% adenine diet in wild-type (WT) and hepcidin gene (Hamp) knockout (KO) mice, compared with their respective littermates fed a regular diet. Experiments were started at weaning (3 wk). After 8 wk, blood was collected and mice were euthanized. Adenine-fed WT mice developed CKD (blood urea nitrogen 82.8 ± 11.6 mg/dl and creatinine 0.57 ± 0.07 mg/dl) and were 2.1 cm shorter compared with WT controls. WT adenine-fed mice were anemic and had low serum iron, elevated Hamp, and elevated IL6 and TNF-α. WT adenine-fed mice had advanced mineral bone disease (serum phosphorus 16.9 ± 3.1 mg/dl and FGF23 204.0 ± 115.0 ng/ml) with loss of cortical and trabecular bone volume seen on microcomputed tomography. Hamp disruption rescued the anemia phenotype resulting in improved growth rate in mice with CKD, thus providing direct experimental evidence of the relationship between Hamp pathway and growth impairment in CKD. Hamp disruption ameliorated CKD-induced growth hormone-insulin-like growth factor 1 axis derangements and growth plate alterations. Disruption of Hamp did not mitigate the development of uremia, inflammation, and mineral and bone disease in this model. Taken together, these results indicate that an adenine diet can be successfully used to study growth in mice with CKD. Hepcidin appears to be related to pathways of growth retardation in CKD suggesting that investigation of hepcidin-lowering therapies in juvenile CKD is warranted. Copyright © 2016 the American Physiological Society.

  12. CHARGE Association

    Directory of Open Access Journals (Sweden)

    Semanti Chakraborty

    2012-01-01

    Full Text Available We present here a case of 17-year-old boy from Kolkata presenting with obesity, bilateral gynecomastia, mental retardation, and hypogonadotrophic hypogonadism. The patient weighed 70 kg and was of 153 cm height. Facial asymmetry (unilateral facial palsy, gynecomastia, decreased pubic and axillary hair, small penis, decreased right testicular volume, non-palpable left testis, and right-sided congenital inguinal hernia was present. The patient also had disc coloboma, convergent squint, microcornea, microphthalmia, pseudohypertelorism, low set ears, short neck, and choanalatresia. He had h/o VSD repaired with patch. Laboratory examination revealed haemoglobin 9.9 mg/dl, urea 24 mg/dl, creatinine 0.68 mg/dl. IGF1 77.80 ng/ml (decreased for age, GH <0.05 ng/ml, testosterone 0.25 ng/ml, FSH-0.95 ΅IU/ml, LH 0.60 ΅IU/ml. ACTH, 8:00 A.M cortisol, FT3, FT4, TSH, estradiol, DHEA-S, lipid profile, and LFT was within normal limits. Prolactin was elevated at 38.50 ng/ml. The patient′s karyotype was 46XY. Echocardiography revealed ventricularseptal defect closed with patch, grade 1 aortic regurgitation, and ejection fraction 67%. Ultrasound testis showed small right testis within scrotal sac and undescended left testis within left inguinal canal. CT scan paranasal sinuses revealed choanalatresia and deviation of nasal septum to the right. Sonomammography revealed bilateral proliferation of fibroglandular elements predominantly in subareoalar region of breasts. MRI of brain and pituitary region revealed markedly atrophic pituitary gland parenchyma with preserved infundibulum and hypothalamus and widened suprasellar cistern. The CHARGE association is an increasingly recognized non-random pattern of congenital anomalies comprising of coloboma, heart defect, choanal atresia, retarded growth and development, genital hypoplasia, ear abnormalities, and/or deafness. [1] These anomalies have a higher probability of occurring together. In this report, we have

  13. Study of CP -violating charge asymmetries of single muons and like-sign dimuons in pp¯ collisions

    Energy Technology Data Exchange (ETDEWEB)

    Abazov, V. M.; Abbott, B.; Acharya, B. S.; Adams, M.; Adams, T.; Agnew, J. P.; Alexeev, G. D.; Alkhazov, G.; Alton, A.; Askew, A.; Atkins, S.; Augsten, K.; Avila, C.; Badaud, F.; Bagby, L.; Baldin, B.; Bandurin, D. V.; Banerjee, S.; Barberis, E.; Baringer, P.; Bartlett, J. F.; Bassler, U.; Bazterra, V.; Bean, A.; Begalli, M.; Bellantoni, L.; Beri, S. B.; Bernardi, G.; Bernhard, R.; Bertram, I.; Besançon, M.; Beuselinck, R.; Bhat, P. C.; Bhatia, S.; Bhatnagar, V.; Blazey, G.; Blessing, S.; Bloom, K.; Boehnlein, A.; Boline, D.; Boos, E. E.; Borissov, G.; Brandt, A.; Brandt, O.; Brock, R.; Bross, A.; Brown, D.; Bu, X. B.; Buehler, M.; Buescher, V.; Bunichev, V.; Burdin, S.; Buszello, C. P.; Camacho-Pérez, E.; Casey, B. C. K.; Castilla-Valdez, H.; Caughron, S.; Chakrabarti, S.; Chan, K. M.; Chandra, A.; Chapon, E.; Chen, G.; Cho, S. W.; Choi, S.; Choudhary, B.; Cihangir, S.; Claes, D.; Clutter, J.; Cooke, M.; Cooper, W. E.; Corcoran, M.; Couderc, F.; Cousinou, M. -C.; Cutts, D.; Das, A.; Davies, G.; de Jong, S. J.; De La Cruz-Burelo, E.; Déliot, F.; Demina, R.; Denisov, D.; Denisov, S. P.; Desai, S.; Deterre, C.; DeVaughan, K.; Diehl, H. T.; Diesburg, M.; Ding, P. F.; Dominguez, A.; Dubey, A.; Dudko, L. V.; Duperrin, A.; Dutt, S.; Eads, M.; Edmunds, D.; Ellison, J.; Elvira, V. D.; Enari, Y.; Evans, H.; Evdokimov, V. N.; Feng, L.; Ferbel, T.; Fiedler, F.; Filthaut, F.; Fisher, W.; Fisk, H. E.; Fortner, M.; Fox, H.; Fuess, S.; Garbincius, P. H.; Garcia-Bellido, A.; García-González, J. A.; Gavrilov, V.; Geng, W.; Gerber, C. E.; Gershtein, Y.; Ginther, G.; Golovanov, G.; Grannis, P. D.; Greder, S.; Greenlee, H.; Grenier, G.; Gris, Ph.; Grivaz, J. -F.; Grohsjean, A.; Grünendahl, S.; Grünewald, M. W.; Guillemin, T.; Gutierrez, G.; Gutierrez, P.; Haley, J.; Han, L.; Harder, K.; Harel, A.; Hauptman, J. M.; Hays, J.; Head, T.; Hebbeker, T.; Hedin, D.; Hegab, H.; Heinson, A. P.; Heintz, U.; Hensel, C.; Heredia-De La Cruz, I.; Herner, K.; Hesketh, G.; Hildreth, M. D.; Hirosky, R.; Hoang, T.; Hobbs, J. D.; Hoeneisen, B.; Hogan, J.; Hohlfeld, M.; Holzbauer, J. L.; Howley, I.; Hubacek, Z.; Hynek, V.; Iashvili, I.; Ilchenko, Y.; Illingworth, R.; Ito, A. S.; Jabeen, S.; Jaffré, M.; Jayasinghe, A.; Jeong, M. S.; Jesik, R.; Jiang, P.; Johns, K.; Johnson, E.; Johnson, M.; Jonckheere, A.; Jonsson, P.; Joshi, J.; Jung, A. W.; Juste, A.; Kajfasz, E.; Karmanov, D.; Katsanos, I.; Kehoe, R.; Kermiche, S.; Khalatyan, N.; Khanov, A.; Kharchilava, A.; Kharzheev, Y. N.; Kiselevich, I.; Kohli, J. M.; Kozelov, A. V.; Kraus, J.; Kumar, A.; Kupco, A.; Kurča, T.; Kuzmin, V. A.; Lammers, S.; Lebrun, P.; Lee, H. S.; Lee, S. W.; Lee, W. M.; Lei, X.; Lellouch, J.; Li, D.; Li, H.; Li, L.; Li, Q. Z.; Lim, J. K.; Lincoln, D.; Linnemann, J.; Lipaev, V. V.; Lipton, R.; Liu, H.; Liu, Y.; Lobodenko, A.; Lokajicek, M.; Lopes de Sa, R.; Luna-Garcia, R.; Lyon, A. L.; Maciel, A. K. A.; Madar, R.; Magaña-Villalba, R.; Malik, S.; Malyshev, V. L.; Mansour, J.; Martínez-Ortega, J.; McCarthy, R.; McGivern, C. L.; Meijer, M. M.; Melnitchouk, A.; Menezes, D.; Mercadante, P. G.; Merkin, M.; Meyer, A.; Meyer, J.; Miconi, F.; Mondal, N. K.; Mulhearn, M.; Nagy, E.; Narain, M.; Nayyar, R.; Neal, H. A.; Negret, J. P.; Neustroev, P.; Nguyen, H. T.; Nunnemann, T.; Orduna, J.; Osman, N.; Osta, J.; Pal, A.; Parashar, N.; Parihar, V.; Park, S. K.; Partridge, R.; Parua, N.; Patwa, A.; Penning, B.; Perfilov, M.; Peters, Y.; Petridis, K.; Petrillo, G.; Pétroff, P.; Pleier, M. -A.; Podstavkov, V. M.; Popov, A. V.; Prewitt, M.; Price, D.; Prokopenko, N.; Qian, J.; Quadt, A.; Quinn, B.; Ratoff, P. N.; Razumov, I.; Ripp-Baudot, I.; Rizatdinova, F.; Rominsky, M.; Ross, A.; Royon, C.; Rubinov, P.; Ruchti, R.; Sajot, G.; Sánchez-Hernández, A.; Sanders, M. P.; Santos, A. S.; Savage, G.; Sawyer, L.; Scanlon, T.; Schamberger, R. D.; Scheglov, Y.; Schellman, H.; Schwanenberger, C.; Schwienhorst, R.; Sekaric, J.; Severini, H.; Shabalina, E.; Shary, V.; Shaw, S.; Shchukin, A. A.; Simak, V.; Skubic, P.; Slattery, P.; Smirnov, D.; Snow, G. R.; Snow, J.; Snyder, S.; Söldner-Rembold, S.; Sonnenschein, L.; Soustruznik, K.; Stark, J.; Stoyanova, D. A.; Strauss, M.; Suter, L.; Svoisky, P.; Titov, M.; Tokmenin, V. V.; Tsai, Y. -T.; Tsybychev, D.; Tuchming, B.; Tully, C.; Uvarov, L.; Uvarov, S.; Uzunyan, S.; Van Kooten, R.; van Leeuwen, W. M.; Varelas, N.; Varnes, E. W.; Vasilyev, I. A.; Verkheev, A. Y.; Vertogradov, L. S.; Verzocchi, M.; Vesterinen, M.; Vilanova, D.; Vokac, P.; Wahl, H. D.; Wang, M. H. L. S.; Warchol, J.; Watts, G.; Wayne, M.; Weichert, J.; Welty-Rieger, L.; Williams, M. R. J.; Wilson, G. W.; Wobisch, M.; Wood, D. R.; Wyatt, T. R.; Xie, Y.; Yamada, R.; Yang, S.; Yasuda, T.; Yatsunenko, Y. A.; Ye, W.; Ye, Z.; Yin, H.; Yip, K.; Youn, S. W.; Yu, J. M.; Zennamo, J.; Zhao, T. G.; Zhou, B.; Zhu, J.; Zielinski, M.; Zieminska, D.; Zivkovic, L.

    2014-01-01

    We measure the inclusive single muon charge asymmetry and the like-sign dimuon charge asymmetry in $p \\bar{p}$ collisions using the full data set of 10.4 fb$^{-1}$ collected with the D0 detector at the Fermilab Tevatron. The standard model predictions of the charge asymmetries induced by CP violation are small in magnitude compared to the current experimental precision, so non-zero measurements could indicate new sources of CP violation. The measurements differ from the standard model predictions of CP violation in these asymmetries with a significance of 3.6 standard deviations. These results are interpreted in a framework of $B$ meson mixing within the CKM formalism to measure the relative width difference $\\dgg$ between the mass eigenstates of the $\\Bd$ meson system, and the semileptonic charge asymmetries $\\asld$ and $\\asls$ of $\\Bd$ and $\\Bs$ mesons respectively.

  14. Nicotinamide Adenine Dinucleotide Phosphate Oxidase 2 Regulates LPS-Induced Inflammation and Alveolar Remodeling in the Developing Lung

    Science.gov (United States)

    Menden, Heather L.; Xia, Sheng; Mabry, Sherry M.; Navarro, Angels; Nyp, Michael F.

    2016-01-01

    In premature infants, sepsis is associated with alveolar simplification manifesting as bronchopulmonary dysplasia. The redox-dependent mechanisms underlying sepsis-induced inflammation and alveolar remodeling in the immature lung remain unclear. We developed a neonatal mouse model of sepsis-induced lung injury to investigate whether nicotinamide adenine dinucleotide phosphate oxidase 2 (NOX2) regulates Toll-like receptor (TLR)–mediated inflammation and alveolar remodeling. Six-day-old NOX2+/+ and NOX2−/− mice were injected with intraperitoneal LPS to induce sepsis. Lung inflammation and canonical TLR signaling were assessed 24 hours after LPS. Alveolar development was examined in 15-day-old mice after LPS on Day 6. The in vivo efficacy of a NOX2 inhibitor (NOX2-I) on NOX2 complex assembly and sepsis-induced lung inflammation were examined. Lung cytokine expression and neutrophil influx induced with sepsis in NOX2+/+ mice was decreased by >50% in NOX2−/− mice. LPS-induced TLR4 signaling evident by inhibitor of NF-κB kinase-β and mitogen-activated protein kinase phosphorylation, and nuclear factor-κB/AP-1 translocation were attenuated in NOX2−/− mice. LPS increased matrix metalloproteinase 9 while decreasing elastin and keratinocyte growth factor levels in NOX2+/+ mice. An LPS-induced increase in matrix metalloproteinase 9 and decrease in fibroblast growth factor 7 and elastin were not evident in NOX2−/− mice. An LPS-induced reduction in radial alveolar counts and increased mean linear intercepts were attenuated in NOX2−/− mice. LPS-induced NOX2 assembly evident by p67phox/gp91phox coimmunoprecipitation was disrupted with NOX2-I. NOX2-I also mitigated LPS-induced cytokine expression, TLR pathway signaling, and alveolar simplification. In a mouse model of neonatal sepsis, NOX2 regulates proinflammatory TLR signaling and alveolar remodeling induced by a single dose of LPS. Our results provide mechanistic insight into the regulation of sepsis

  15. Rigid Adenine Nucleoside Derivatives as Novel Modulators of the Human Sodium Symporters for Dopamine and Norepinephrine

    Science.gov (United States)

    Tosh, Dilip K.; Eshleman, Amy J.; Jacobson, Kenneth A.

    2016-01-01

    Thirty-two congeneric rigid adenine nucleoside derivatives containing a North (N)-methanocarba ribose substitution and a 2-arylethynyl group either enhanced (up to 760% of control) or inhibited [125I] methyl (1R,2S,3S)-3-(4-iodophenyl)-8-methyl-8-azabicyclo[3.2.1]octane-2-carboxylate (RTI-55) binding at the human dopamine (DA) transporter (DAT) and inhibited DA uptake. Several nucleosides also enhanced [3H]mazindol [(±)-5-(4-chlorophenyl)-3,5-dihydro-2H-imidazo[2,1-a]isoindol-5-ol] binding to the DAT. The combination of binding enhancement and functional inhibition suggests possible allosteric interaction with the tropanes. The structure-activity relationship of this novel class of DAT ligands was explored: small N6-substition (methyl or ethyl) was favored, while the N1 of the adenine ring was essential. Effective terminal aryl groups include thien-2-yl (compounds 9 and 16), with EC50 values of 35.1 and 9.1 nM, respectively, in [125I]RTI-55 binding enhancement, and 3,4-difluorophenyl as in the most potent DA uptake inhibitor (compound 6) with an IC50 value of 92 nM (3-fold more potent than cocaine), but not nitrogen heterocycles. Several compounds inhibited or enhanced binding at the norepinephrine transporter (NET) and serotonin transporter (SERT) and inhibited function in the micromolar range; truncation at the 4′-position in compound 23 allowed for weak inhibition of the SERT. We have not yet eliminated adenosine receptor affinity from this class of DAT modulators, but we identified modifications that remove DAT inhibition as an off-target effect of potent adenosine receptor agonists. Thus, we have identified a new class of allosteric DAT ligands, rigidified adenosine derivatives, and explored their initial structural requirements. They display a very atypical pharmacological profile, i.e., either enhancement by increasing affinity or inhibition of radioligand binding at the DAT, and in some cases the NET and SERT, and inhibition of neurotransmitter uptake

  16. The C-terminal domain of the adenine-DNA glycosylase MutY confers specificity for 8-oxoguanine.adenine mispairs and may have evolved from MutT, an 8-oxo-dGTPase.

    Science.gov (United States)

    Noll, D M; Gogos, A; Granek, J A; Clarke, N D

    1999-05-18

    MutY is an adenine-DNA glycosylase with specificity for mismatches involving 8-oxoguanine (oG.A) or guanine (G.A). In addition to a 25 kDa catalytic domain common to all members of its DNA glycosylase superfamily, MutY has a 14 kDa C-terminal domain. Sequence analyses suggest that this C-terminal domain is distantly related to MutT, a pyrophosphohydrolase specific for 2'-deoxy-8-oxoguanosine triphosphate (doGTP). Here we present biochemical evidence that the MutT-like domain of MutY is the principal determinant of oG specificity. First, MutY dissociates approximately 1500-fold more slowly from oG-containing product DNA than from G-containing product, but a truncated protein lacking the C-terminal domain dissociates as rapidly from oG-DNA as the full-length protein dissociates from G-DNA. Second, MutY removes adenine from oG.A mismatches almost 30-fold faster than from G.A mismatches in a pre-steady-state assay, but deletion of the C-terminal domain reduces this specificity for oG.A to less than 4-fold. The kinetic data are consistent with a model in which binding of oG to the C-terminal domain of MutY accelerates the pre-steady-state glycosylase reaction by facilitating adenine base flipping. The observation that oG specificity derives almost exclusively from the C-terminal domain of MutY adds credence to the sequence analyses and suggests that specificity for oG.A mismatches was acquired by fusion of a MutT-like protein onto the core catalytic domain of an adenine-DNA glycosylase.

  17. Workplace Charging. Charging Up University Campuses

    Energy Technology Data Exchange (ETDEWEB)

    Giles, Carrie [ICF International, Fairfax, VA (United States); Ryder, Carrie [ICF International, Fairfax, VA (United States); Lommele, Stephen [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2016-03-01

    This case study features the experiences of university partners in the U.S. Department of Energy's (DOE) Workplace Charging Challenge with the installation and management of plug-in electric vehicle (PEV) charging stations.

  18. Macrocluster desorption effect caused by single MCI: charges of gold clusters (2-20 nm) desorbed due to electronic processes induced by fission fragment bombardment in nanodispersed gold targets

    International Nuclear Information System (INIS)

    Baranov, I.; Jarmiychuk, S.; Kirillov, S.; Novikov, A.; Obnorskii, V.; Pchelintsev, A.; Wien, K.; Reimann, C.

    1999-01-01

    In this work the charge state of the negatively charged gold nanocluster ions (2-20 nm) that were desorbed from nanodispersed gold islet targets by 252 Cf fission fragments via electronic processes is studied. Mean cluster charge was calculated as a ratio of mean cluster mass to mean mass-to-charge ratio . Cluster masses were measured by means of a collector technique employing transmission electron microscopy and scanning force microscopy, while m/q was measured by means of a tandem TOF-spectrometer. It is shown that the nanocluster ions are mostly multiply charged (2-16e) and the charge increases non-linearly with the cluster size. The results are discussed

  19. Surface Hopping Dynamics with Correlated Single-Reference Methods: 9H-Adenine as a Case Study

    Czech Academy of Sciences Publication Activity Database

    Plasser, F.; Crespo-Otero, R.; Pederzoli, Marek; Pittner, Jiří; Lischka, H.; Barbatti, M.

    2014-01-01

    Roč. 10, č. 4 (2014), s. 1395-1405 ISSN 1549-9618 R&D Projects: GA ČR(CZ) GAP208/12/0559 Institutional support: RVO:61388955 Keywords : density-functional theory * resolved photoelectron spectroscopy * nonadiabatic molecular dynamics Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 5.498, year: 2014

  20. Application of a new method for detecting streptococcal nicotinamide adenine dinucleotide glycohydrolase to various M types of Streptoccus pyogenes.

    Science.gov (United States)

    Lütticken, R; Lütticken, D; Johnson, D R; Wannamaker, L W

    1976-05-01

    The production of extracellular nicotinamide adenine dinucleotide glycohydrolase (NADase) by Streptococcus pyogenes can easily be demonstrated using the fluorescence of nicotinamide adenine dinucleotide in ultraviolet light occurring on addition of strong alkali. The new method described here uses microtiter plates and can be read with the naked eye. It permits the screening of large numbers of strains in a short time and with minimal amounts of reagents. The sensitivity of the new method proved to be good in comparison with the bisulfite spectrophotometric method. Culture supernatants of 177 group A streptococci were tested for NADase production by the microtiter fluorescence method. We could confirm former findings that strains within a certain M type of S. pyogenes are usually either producers or nonproducers of the enzyme. The usefulness of the test for screening of streptococcal NADase production is discussed.

  1. High-NaCl diet impairs dynamic renal blood flow autoregulation in rats with adenine-induced chronic renal failure

    DEFF Research Database (Denmark)

    Saeed, Aso; DiBona, Gerald F; Grimberg, Elisabeth

    2014-01-01

    This study examined the effects of 2 wk of high-NaCl diet on kidney function and dynamic renal blood flow autoregulation (RBFA) in rats with adenine-induced chronic renal failure (ACRF). Male Sprague-Dawley rats received either chow containing adenine or were pair-fed an identical diet without...... arterial pressure variability (SAPV), and heart rate variability were assessed by spectral analytical techniques. Rats with ACRF showed marked reductions in glomerular filtration rate and renal blood flow (RBF), whereas mean arterial pressure and SAPV were significantly elevated. In addition, spontaneous...... BRS was reduced by ∼50% in ACRF animals. High-NaCl diet significantly increased transfer function fractional gain values between arterial pressure and RBF in the frequency range of the myogenic response (0.06-0.09 Hz) only in ACRF animals (0.3 ± 4.0 vs. -4.4 ± 3.8 dB; P

  2. Synthesis of adenine, guanine, cytosine, and other nitrogen organic compounds by a Fischer-Tropsch-like process.

    Science.gov (United States)

    Yang, C. C.; Oro, J.

    1971-01-01

    Study of the formation of purines, pyrimidines, and other bases from CO, H2, and NH3 under conditions similar to those used in the Fischer-Tropsch process. It is found that industrial nickel/iron alloy catalyzes the synthesis of adenine, guanine, cytosine, and other nitrogenous compounds from mixtures of CO, H2, and NH3 at temperatures of about 600 C. Sufficient sample was accumulated to isolate as solid products adenine, guanine, and cytosine, which were identified by infrared spectrophotometry. In the absence of nickel/iron catalyst, at 650 C, or in the presence of this catalyst, at 450 C, no purines or pyrimidines were synthesized. These results confirm and extend some of the work reported by Kayatsu et al. (1968).

  3. The metabolism of N6(Δ2-isosopentenyl) [3H]adenine by different stem sections of Pisum sativum

    International Nuclear Information System (INIS)

    King, R.A.; Staden, J. van

    1990-01-01

    Serial segments of internodal stem tissue were isolated from Pisum sativum L. shoots and incubated in a medium containing N 6 (Δ 2 -isosopentenyl) [ 3 H]adenine. The recovery of radioactive derivatives separated using HPLC indicated a gradient of cytokinin metabolic activity in the stem. This gradient of activity was found to be greatest at the basal node in young seedlings but was high both at upper and lower nodes in older plants. An attempt to correlate this phenomenon with the basipetally decreasing concentration of indole-3-acetic acid in the stem led to an experiment in which stem segments were pretreated in indole-3-acetic acid solutions before incubating in a medium containing N 6 (Δ 2 -isosopentenyl) [ 3 H]adenine. Indole-3-acetic acid was found to have a marked effect on cytokinin metabolism in isolated stem segments. These results are discussed in relation to apical dominance in the shoot. (author)

  4. Detection of Guanine and Adenine Using an Aminated Reduced Graphene Oxide Functional Membrane-Modified Glassy Carbon Electrode

    Directory of Open Access Journals (Sweden)

    Di Li

    2017-07-01

    Full Text Available A new electrochemical sensor based on a Nafion, aminated reduced graphene oxide and chitosan functional membrane-modified glassy carbon electrode was proposed for the simultaneous detection of adenine and guanine. Fourier transform-infrared spectrometry (FTIR, transmission electron microscopy (TEM, and electrochemical methods were utilized for the additional characterization of the membrane materials. The prepared electrode was utilized for the detection of guanine (G and adenine (A. The anodic peak currents to G and A were linear in the concentrations ranging from 0.1 to 120 μM and 0.2 to 110 μM, respectively. The detection limits were found to be 0.1 μM and 0.2 μM, respectively. Moreover, the modified electrode could also be used to determine G and A in calf thymus DNA.

  5. First principle study of the electronic structure, Fermi surface, electronic charge density and optical properties of ThCu{sub 5}In and ThCu{sub 5}Sn single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Reshak, A.H. [Institute of complex systems, FFPW, CENAKVA-University of South Bohemia in CB, Nove Hrady 37333 (Czech Republic); Center of Excellence Geopolymer and Green Technology, School of Material Engineering, University Malaysia Perlis, 01007 Kangar, Perlis (Malaysia); Azam, Sikander, E-mail: sikander.physicst@gmail.com [Institute of complex systems, FFPW, CENAKVA-University of South Bohemia in CB, Nove Hrady 37333 (Czech Republic)

    2014-02-15

    The electronic structure, Fermi surface, electronic charge density and optical properties of ThCu{sub 5}In and ThCu{sub 5}Sn single crystals are studied. The calculations are based on the full potential-linearized augmented plane wave (FPLAPW) method. The exchange and correlation potential is treated by the local density approximation (LDA) and generalized-gradient approximation (GGA), in addition the Engel–Vosko (EV-GGA) formalism was also applied. The DFT calculations show that these compounds have metallic origin. The contribution of different bands was analyzed from total and partial density of states curves. The values of the density of states at Fermi energy (N(E{sub F})) for ThCu{sub 5}In (ThCu{sub 5}Sn) is 1.75 (1.63) states/eV unit cell. The bare electronic specific heat coefficient (γ) is found to be equal to 0.30 and 0.28 mJ/mol-K{sup 2} for ThCu{sub 5}In and ThCu{sub 5}Sn, respectively. The Fermi surface of ThCu{sub 5}In/ThCu{sub 5}Sn is composed of three/four bands crossing along the R–Γ direction. The bonding features are analyzed by using the electronic charge density contour in the (101) crystallographic plane and it shows the covalent character of Cu–Cu and Sn/In–Cu bonds. The optical properties were also calculated and analyzed. - Highlights: • The DFT-FPLAPW method used for calculating the properties of ThCu{sub 5}In and ThCu{sub 5}Sn compounds. • This study shows that the nature of the two compounds is metallic. • Crystallographic plane and it shows the covalent character of Cu–Cu and Sn/In–Cu bonds. • The optical properties were also calculated and analyzed. • The Fermi surface of ThCu{sub 5}In/ThCu{sub 5}Sn is composed of three/four bands crossing along the R–Γ direction.

  6. Stimulation of nicotinamide adenine dinucleotide biosynthetic pathways delays axonal degeneration after axotomy.

    Science.gov (United States)

    Sasaki, Yo; Araki, Toshiyuki; Milbrandt, Jeffrey

    2006-08-16

    Axonal degeneration occurs in many neurodegenerative diseases and after traumatic injury and is a self-destructive program independent from programmed cell death. Previous studies demonstrated that overexpression of nicotinamide mononucleotide adenylyltransferase 1 (Nmnat1) or exogenous application of nicotinamide adenine dinucleotide (NAD) can protect axons of cultured dorsal root ganglion (DRG) neurons from degeneration caused by mechanical or neurotoxic injury. In mammalian cells, NAD can be synthesized from multiple precursors, including tryptophan, nicotinic acid, nicotinamide, and nicotinamide riboside (NmR), via multiple enzymatic steps. To determine whether other components of these NAD biosynthetic pathways are capable of delaying axonal degeneration, we overexpressed each of the enzymes involved in each pathway and/or exogenously administered their respective substrates in DRG cultures and assessed their capacity to protect axons after axotomy. Among the enzymes tested, Nmnat1 had the strongest protective effects, whereas nicotinamide phosphoribosyl transferase and nicotinic acid phosphoribosyl transferase showed moderate protective activity in the presence of their substrates. Strong axonal protection was also provided by Nmnat3, which is predominantly located in mitochondria, and an Nmnat1 mutant localized to the cytoplasm, indicating that the subcellular location of NAD production is not crucial for protective activity. In addition, we showed that exogenous application of the NAD precursors that are the substrates of these enzymes, including nicotinic acid mononucleotide, nicotinamide mononucleotide, and NmR, can also delay axonal degeneration. These results indicate that stimulation of NAD biosynthetic pathways via a variety of interventions may be useful in preventing or delaying axonal degeneration.

  7. Human Adenine Nucleotide Translocase (ANT) Modulators Identified by High-Throughput Screening of Transgenic Yeast.

    Science.gov (United States)

    Zhang, Yujian; Tian, Defeng; Matsuyama, Hironori; Hamazaki, Takashi; Shiratsuchi, Takayuki; Terada, Naohiro; Hook, Derek J; Walters, Michael A; Georg, Gunda I; Hawkinson, Jon E

    2016-04-01

    Transport of ADP and ATP across mitochondria is one of the primary points of regulation to maintain cellular energy homeostasis. This process is mainly mediated by adenine nucleotide translocase (ANT) located on the mitochondrial inner membrane. There are four human ANT isoforms, each having a unique tissue-specific expression pattern and biological function, highlighting their potential as drug targets for diverse clinical indications, including male contraception and cancer. In this study, we present a novel yeast-based high-throughput screening (HTS) strategy to identify compounds inhibiting the function of ANT. Yeast strains generated by deletion of endogenous proteins with ANT activity followed by insertion of individual human ANT isoforms are sensitive to cell-permeable ANT inhibitors, which reduce proliferation. Screening hits identified in the yeast proliferation assay were characterized in ADP/ATP exchange assays employing recombinant ANT isoforms expressed in isolated yeast mitochondria and Lactococcus lactis as well as by oxygen consumption rate in mammalian cells. Using this approach, closantel and CD437 were identified as broad-spectrum ANT inhibitors, whereas leelamine was found to be a modulator of ANT function. This yeast "knock-out/knock-in" screening strategy is applicable to a broad range of essential molecular targets that are required for yeast survival. © 2016 Society for Laboratory Automation and Screening.

  8. DNA adenine methylation is required to replicate both Vibrio cholerae chromosomes once per cell cycle.

    Directory of Open Access Journals (Sweden)

    Gaëlle Demarre

    2010-05-01

    Full Text Available DNA adenine methylation is widely used to control many DNA transactions, including replication. In Escherichia coli, methylation serves to silence newly synthesized (hemimethylated sister origins. SeqA, a protein that binds to hemimethylated DNA, mediates the silencing, and this is necessary to restrict replication to once per cell cycle. The methylation, however, is not essential for replication initiation per se but appeared so when the origins (oriI and oriII of the two Vibrio cholerae chromosomes were used to drive plasmid replication in E. coli. Here we show that, as in the case of E. coli, methylation is not essential for oriI when it drives chromosomal replication and is needed for once-per-cell-cycle replication in a SeqA-dependent fashion. We found that oriII also needs SeqA for once-per-cell-cycle replication and, additionally, full methylation for efficient initiator binding. The requirement for initiator binding might suffice to make methylation an essential function in V. cholerae. The structure of oriII suggests that it originated from a plasmid, but unlike plasmids, oriII makes use of methylation for once-per-cell-cycle replication, the norm for chromosomal but not plasmid replication.

  9. Functional expression of human adenine nucleotide translocase 4 in Saccharomyces cerevisiae.

    Directory of Open Access Journals (Sweden)

    Takashi Hamazaki

    2011-04-01

    Full Text Available The adenine nucleotide translocase (ANT mediates the exchange of ADP and ATP across the inner mitochondrial membrane. The human genome encodes multiple ANT isoforms that are expressed in a tissue-specific manner. Recently a novel germ cell-specific member of the ANT family, ANT4 (SLC25A31 was identified. Although it is known that targeted depletion of ANT4 in mice resulted in male infertility, the functional biochemical differences between ANT4 and other somatic ANT isoforms remain undetermined. To gain insight into ANT4, we expressed human ANT4 (hANT4 in yeast mitochondria. Unlike the somatic ANT proteins, expression of hANT4 failed to complement an AAC-deficient yeast strain for growth on media requiring mitochondrial respiration. Moreover, overexpression of hANT4 from a multi-copy plasmid interfered with optimal yeast growth. However, mutation of specific amino acids of hANT4 improved yeast mitochondrial expression and supported growth of the AAC-deficient yeast on non-fermentable carbon sources. The mutations affected amino acids predicted to interact with phospholipids, suggesting the importance of lipid interactions for function of this protein. Each mutant hANT4 and the somatic hANTs exhibited similar ADP/ATP exchange kinetics. These data define common and distinct biochemical characteristics of ANT4 in comparison to ANT1, 2 and 3 providing a basis for study of its unique adaptation to germ cells.

  10. Functional expression of human adenine nucleotide translocase 4 in Saccharomyces cerevisiae.

    Science.gov (United States)

    Hamazaki, Takashi; Leung, Wai-Yee; Cain, Brian D; Ostrov, David A; Thorsness, Peter E; Terada, Naohiro

    2011-04-21

    The adenine nucleotide translocase (ANT) mediates the exchange of ADP and ATP across the inner mitochondrial membrane. The human genome encodes multiple ANT isoforms that are expressed in a tissue-specific manner. Recently a novel germ cell-specific member of the ANT family, ANT4 (SLC25A31) was identified. Although it is known that targeted depletion of ANT4 in mice resulted in male infertility, the functional biochemical differences between ANT4 and other somatic ANT isoforms remain undetermined. To gain insight into ANT4, we expressed human ANT4 (hANT4) in yeast mitochondria. Unlike the somatic ANT proteins, expression of hANT4 failed to complement an AAC-deficient yeast strain for growth on media requiring mitochondrial respiration. Moreover, overexpression of hANT4 from a multi-copy plasmid interfered with optimal yeast growth. However, mutation of specific amino acids of hANT4 improved yeast mitochondrial expression and supported growth of the AAC-deficient yeast on non-fermentable carbon sources. The mutations affected amino acids predicted to interact with phospholipids, suggesting the importance of lipid interactions for function of this protein. Each mutant hANT4 and the somatic hANTs exhibited similar ADP/ATP exchange kinetics. These data define common and distinct biochemical characteristics of ANT4 in comparison to ANT1, 2 and 3 providing a basis for study of its unique adaptation to germ cells.

  11. Magnitude of malate-aspartate reduced nicotinamide adenine dinucleotide shuttle activity in intact respiring tumor cells.

    Science.gov (United States)

    Greenhouse, W V; Lehninger, A L

    1977-11-01

    Measurements of respiration, CO2 and lactate production, and changes in the levels of various key metabolites of the glycolytic sequence and tricarboxylic acid cycle were made on five lines of rodent ascites tumor cells (two strains of Ehrlich ascites tumor cells, Krebs II carcinoma, AS-30D carcinoma, and L1210 cells) incubated aerobically in the presence of uniformly labeled D-[14C]glucose. From these data, as well as earlier evidence demonstrating that the reduced nicotinamide adenine dinucleotide (NADH) shuttle in these cells requires a transaminase step and is thus identified as the malate-aspartate shuttle (W.V.V. Greenhouse and A.L. Lehninger, Cancer Res., 36: 1392-1396, 1976), metabolic flux diagrams were constructed for the five cell lines. These diagrams show the relative rates of glycolysis, the tricarboxylic acid cycle, electron transport, and the malate-aspartate shuttle in these tumors. Large amounts of cytosolic NADH were oxidized by the mitochondrial respiratory chain via the NADH shuttle, comprising anywhere from about 20 to 80% of the total flow of reducing equivalents to oxygen in these tumors. Calculations of the sources of energy for adenosine triphosphate synthesis indicated that on the average about one-third of the respiratory adenosine triphosphate is generated by electron flow originating from cytosolic NADH via the malate-aspartate shuttle.

  12. Studies of yeast cell oxygenation and energetics by laser fluorometry of reduced nicotinamide adenine dinucleotide

    Science.gov (United States)

    Pan, Fu-shih; Chen, Stephen; Mintzer, Robert A.; Chen, Chin-Tu; Schumacker, Paul

    1991-03-01

    It is of fundamental importance for biological scientists to assess cellular energetics. Under aerobic conditions, the tricarboxylic acid cycle (TCA cycle) is coupled with the mitochondrial electron cascade pathway to provide the cell with energy. The nicotinamide adenine dinucleotide-conjugated pair (NAD and NADH) is the coenzyme in numerous important biomedical reactions which include several important dehydrogenase reactions in the TCA cycle. Based on Le Chatelier's principle, NADH will accumulate when this energy production mechanism is impaired. The relative amounts of NAD and NADH in a cell are defined as the redox state of the cell (Williamson et.al. 1967) which provides a valuable index of cellular energetics. The sum of the amounts of NAD and NADH in a cell may be assumed to be constant during a finite time; therefore, a reliable means of measuring the NADH concentration would provide us with a useful indicator of tissue viability. Traditionally, the quantities of NADH and NAD may be measured by chemical assay methods. We can avoid these tediois analyses by exploiting the significant difference between the ultraviolet absorption spectra of this redox pair. However, because of the opacity of biological samples and the interference of other biochemicals that also absorb ultraviolet radiation, measurement of NADH and NAD+ concentrations in vivo by absorption spectroscopy is not feasible.

  13. Divalent phosphate is a counterion for carboxyatractyloside-insensitive adenine nucleotide transport in rat liver mitochondria

    International Nuclear Information System (INIS)

    Nosek, M.T.; Aprille, J.R.

    1986-01-01

    Unidirectional, carboxyatractyloside(CAT)-insensitive adenine nucleotide (AdN) fluxes have been studied in isolated rat liver mitochondria (mito). Previous work has shown that ATP x Mg transport in one direction is coupled to ATP x Mg or P/sub i/ transport in the opposite direction. The purpose of this study was to determine whether divalent HPO 4 2- or monovalent H 2 PO 4 - is the transported phosphate species. The authors used the monofluorophosphate (PO 3 F 2- ) and difluorophosphate (PO 2 F 2 - ) analogues as potential counterions forAdN efflux. After a preincubation on ice with 14 C-ADP to label the matrix AdN, efflux was measured at 30 0 C, pH 7.4, in 225mM sucrose, 10mM KCl, 5mM MgCl 2 , 5mM glutamate, 5mM malate, 10mM Tris, 0.5mM P/sub i/, 1mM ATP, and 5μM CAT. With no other additions efflux was -0.62 +/- 0.20 nmole/minute/mg protein. The data supports the hypothesis that divalent but not monovalent phosphate can act as a counterion for ATPx Mg transport over this CAT-insensitive carrier

  14. Gas-phase spectroscopy of protonated adenine, adenosine 5′-monophosphate and monohydrated ions

    DEFF Research Database (Denmark)

    Pedersen, S.O.; Støchkel, K.; Byskov, C.S.

    2013-01-01

    . The yields of these were measured as a function of the wavelength of the light from 210 nm to 300 nm, and they were combined to obtain the total photoinduced dissociation at each wavelength (i.e., action spectrum). A broad band between 230 nm and 290 nm and the tail of a band with maximum below 210 nm (high......-energy band) are seen. In the case of AdeH+(H2O), the dominant dissociation channel after photoexcitation in the low-energy band was simply loss of H2O while photodissociation of protonated AMP revealed two dominant dissociation channels associated with the formation of either AdeH+ or loss of H3PO4....... The action spectra of AdeH+, AdeH+(H2O), and AMPH+ are almost identical in the 230–290 nm region, and they resemble the absorption spectrum of protonated adenine in aqueous solution recorded at low pH. Hence from our work it is firmly established that the lowest-energy transitions are independent...

  15. Towards a better understanding of the unusual conformations of the alternating guanine-adenine repeat strands of DNA

    Czech Academy of Sciences Publication Activity Database

    Kejnovská, Iva; Kypr, Jaroslav; Vondrušková, Jitka; Vorlíčková, Michaela

    2007-01-01

    Roč. 85, č. 1 (2007), s. 19-27 ISSN 0006-3525 R&D Projects: GA AV ČR(CZ) IAA4004201; GA AV ČR(CZ) IAA5004802 Institutional research plan: CEZ:AV0Z50040702 Keywords : CD spectroscopy * alternating guanine-adenine microsatellite * guanine quadruplex Subject RIV: BO - Biophysics Impact factor: 2.389, year: 2007

  16. Kinetics and thermodynamics of the reaction between the •OH radical and adenine – a theoretical investigation

    DEFF Research Database (Denmark)

    Milhøj, Birgitte Olai; Sauer, Stephan P. A.

    2015-01-01

    The accessibility of all possible reaction paths for the reaction between the nucleobase adenine and the •OH radical is investigated through quantum chemical calculations of barrier heights and rate constants at the wB97X-D/6-311++G(2df,2pd) level with Eckart tunneling corrections. First the comp......The accessibility of all possible reaction paths for the reaction between the nucleobase adenine and the •OH radical is investigated through quantum chemical calculations of barrier heights and rate constants at the wB97X-D/6-311++G(2df,2pd) level with Eckart tunneling corrections. First...... and with the Wigner, Bell and Eckart corrections. Compared to CCSD(T)//BHandHLYP/aug-cc-pVTZ reference results, the wB97XD/6-311++G(2df,2pd) method combined with Eckart tunneling corrections provides a sensible compromise between accuracy and time. Using this method all sub-reactions of the reaction between adenine...

  17. DNA synthesis and cell survival after X-irradiation of mammalian cells treated with caffeine or adenine

    International Nuclear Information System (INIS)

    Griffiths, T.D.; Carpenter, J.G.; Dahle, D.B.

    1978-01-01

    The expression of the transient depression in the rate of DNA synthesis normally observed after exposure of randomly-dividing Chinese hamster V-79 or Chinese hamster CHO cells to ionizing radiation could be postponed by a post-irradiation treatment with 1.0 to 2.0 mM adenine or 1.5 mM caffeine. Caffeine may exert its effect by creating additional sites for replication in irradiated cells. Cells treated with caffeine or adenine for 2 or 4 hours after exposure to 3000 rad of 300 kVp X-rays exhibited depressed synthesis only after the removal of caffeine or adenine. These alterations in the timing of the X-ray-induced depression of the rate of DNA synthesis had no effect on X-ray-induced cell killing. Although a 4 hour post-irradiation treatment of randomly-dividing Chinese hamster V-79 cells with 1.0 or 2.0 mM caffeine potentiated X-ray-induced cell killing, this reduction in survival was due primarily to effects on cells not in S-phase. (author)

  18. Enabling fast charging - Vehicle considerations

    Science.gov (United States)

    Meintz, Andrew; Zhang, Jiucai; Vijayagopal, Ram; Kreutzer, Cory; Ahmed, Shabbir; Bloom, Ira; Burnham, Andrew; Carlson, Richard B.; Dias, Fernando; Dufek, Eric J.; Francfort, James; Hardy, Keith; Jansen, Andrew N.; Keyser, Matthew; Markel, Anthony; Michelbacher, Christopher; Mohanpurkar, Manish; Pesaran, Ahmad; Scoffield, Don; Shirk, Matthew; Stephens, Thomas; Tanim, Tanvir

    2017-11-01

    To achieve a successful increase in the plug-in battery electric vehicle (BEV) market, it is anticipated that a significant improvement in battery performance is required to increase the range that BEVs can travel and the rate at which they can be recharged. While the range that BEVs can travel on a single recharge is improving, the recharge rate is still much slower than the refueling rate of conventional internal combustion engine vehicles. To achieve comparable recharge times, we explore the vehicle considerations of charge rates of at least 400 kW. Faster recharge is expected to significantly mitigate the perceived deficiencies for long-distance transportation, to provide alternative charging in densely populated areas where overnight charging at home may not be possible, and to reduce range anxiety for travel within a city when unplanned charging may be required. This substantial increase in charging rate is expected to create technical issues in the design of the battery system and the vehicle's electrical architecture that must be resolved. This work focuses on vehicle system design and total recharge time to meet the goals of implementing improved charge rates and the impacts of these expected increases on system voltage and vehicle components.

  19. Activity of nicotinic acid substituted nicotinic acid adenine dinucleotide phosphate (NAADP) analogs in a human cell line: difference in specificity between human and sea urchin NAADP receptors.

    Science.gov (United States)

    Ali, Ramadan A; Zhelay, Tetyana; Trabbic, Christopher J; Walseth, Timothy F; Slama, James T; Giovannucci, David R; Wall, Katherine A

    2014-02-01

    Nicotinic acid adenine dinucleotide phosphate (NAADP) is the most potent Ca2+ mobilizing second messenger that has been identified. We have previously shown that NAADP analogs substituted at the 5-position of nicotinic acid were recognized by the sea urchin receptor at low concentration, whereas the 4- substituted analogs were not as potent. However, to date the structure-activity relationship (SAR) of these analogs has not been addressed in mammalian systems. Thus, we asked whether these structurally modified analogs behave similarly in an NAADP-responsive mammalian cell line (SKBR3) using microinjection and single cell fluorescent imaging methods. Novel "caged" 4- and 5-substituted NAADP analogs that were activated inside the cell by flash photolysis resulted in Ca2+ mobilizing activity in SKBR3 cells in a concentration dependent manner, but with reduced effectiveness compared to unmodified NAADP. The SAR in mammalian SKBR3 cells was quite different from that of sea urchin and may suggest that there are differences between NAADP receptors in different species or tissues. Importantly, these data indicate that modifications at the 4- and 5-position of the nicotinic acid ring may lead to the development of functional photoaffinity labels that could be used for receptor localization and isolation in mammalian systems. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Isolation and characterization of Avibacterium paragallinarum with different nicotinamide adenine dinucleotide requirements.

    Science.gov (United States)

    Jeong, Ok-Mi; Kang, Min-Su; Jeon, Byung-Woo; Choi, Byung-Kook; Kwon, Yong-Kuk; Yoon, So-Youn; Blackall, Patrick J; Lee, Hee-Soo; Jung, Suk-Chan; Kim, Jae-Hong

    2017-06-01

    Twenty field isolates of Avibacterium paragallinarum were obtained from chickens in South Korea during 2011-2015. The isolates were identified by a HPG-2 PCR assay specific for A. paragallinarum and by biochemical tests. Growth requirements, Page serovars, carbohydrate fermentation patterns, and antimicrobial susceptibility were also examined. Most isolates (16/20) showed the typical requirement for nicotinamide adenine dinucleotide (NAD) and an enriched CO 2 atmosphere for growth. One isolate needed increased levels of NAD and serum for good growth. Three isolates showed NAD-independent growth on blood agar under aerobic conditions. In terms of carbohydrate fermentation patterns, three biochemical biovars were recognized; these varied with respect to acid production from maltose and D-xylose. The 16 typical NAD-dependent isolates were serovar A while the variants, both NAD-independent isolates and the isolate with increased NAD dependency were non-typeable. All isolates were sensitive to amoxicillin-clavulanic acid, ceftiofur, gentamicin, and spectinomycin. High rates of resistance, including intermediate resistance, to lincomycin (100%), cloxacillin (75%), and erythromycin (70%) were observed. The four variant strains (the three NAD-independent isolates and the isolate showing unusual growth requirements) were more resistant to antibiotics than the typical NAD-dependent strains. The finding of NAD-independent forms of A. paragallinarum extends the known distribution of this form, previously only reported in South Africa, Mexico and Peru. There is clearly a need for increased caution in the diagnosis and, possibly, the control of infectious coryza. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Transcriptome and Functional Genomics Reveal the Participation of Adenine Phosphoribosyltransferase in Trypanosoma cruzi Resistance to Benznidazole.

    Science.gov (United States)

    García-Huertas, Paola; Mejía-Jaramillo, Ana María; González, Laura; Triana-Chávez, Omar

    2017-07-01

    Currently, the only available treatments for Trypanosoma cruzi are benznidazole (Bz) and nifurtimox (Nfx). The mechanisms of action and resistance to these drugs in this parasite are not complete known. In order to identify differentially expressed transcripts between sensitive and resistant parasites, a massive pyrosequencing of the T. cruzi transcriptome was carried out. Additionally, the 2D gel electrophoresis profile of sensitive and resistant parasites was analyzed and the data were supported with functional genomics. The results showed 133 differentially expressed genes in resistant parasites. The transcriptome analysis revealed the regulation of different genes with several functions and metabolic pathways, which could suggest that resistance in T. cruzi is a multigenic process. Additionally, using transcriptomics, one gene, adenine phosphoribosyltransferase (APRT), was found to be down-regulated in the resistant parasites and its expression profile was confirmed by 2D electrophoresis analysis. The role of this gene in the resistance to Bz was confirmed overexpressing it in sensitive and resistant parasites. Interestingly, both parasites became more sensitive to Bz and H 2 O 2 . This is the first RNA-seq study to identify regulated genes in T. cruzi associated with Bz resistance and to show the role of APRT in T. cruzi resistance. Although T. cruzi regulation is mainly post-transcriptional, the transcriptome analysis, supported by 2D gel analysis and functional genomic, provides an overall idea of the expression profiles of genes under resistance conditions. These results contribute essential information to further the understanding of the mechanisms of action and resistance to Bz in T. cruzi. J. Cell. Biochem. 118: 1936-1945, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  2. Improving quality indices of Rosa ‘Yellow Finesse’ using methyl jasmonate and benzyl adenine

    Directory of Open Access Journals (Sweden)

    Omid Askari-Khorasgani

    2016-06-01

    Full Text Available Plant growth regulators (PGRs play a key role in regulating physiological and morphological development of plant species. Application of these PGRs can improve pre- and post-harvest quality and quantity of ornamental flowers and lessen the harmful effects of injury incurred at harvesting time. The objective of this study was to determine the appropriate spraying solution for improving pre- and postharvest quality indices of Rosa hybrida L. cv. ‘Yellow Finesse’. So, the effect of methyl jasmonate (MeJA at 0, 50, 100, or 150 mg*l-1 alone or in combination with benzyl adenine (BA at 0, 10, or 20 mg*l-1 was investigated. Plants were sprayed at a 15-day interval for two months and then harvested at a mature bud stage. The results showed that flower head diameter and leaf chlorophyll content were improved by applying 100 mg*l-1 MeJA + 20 mg*l-1 BA. The application of 100 mg*l-1 MeJA + 10 mg*l-1 BA or 10 mg*l-1 BA resulted in improving its petal carotenoid content. The plants treated with 150 mg*l-1 MeJA had the longest shelf life. The findings demonstrated that while 100 mg*l-1 MeJA + 20 mg*l-1 BA and 100 mg*l-1 MeJA + 10 mg*l-1 BA were the best preharvest spraying solutions due to the highest carotenoid content and largest flower head diameter. Particularly, 150 mg*l-1 MeJA was the best spraying solution for extending cut flower shelf life and had the potential to function as a postharvest treatment.

  3. Adenine nucleotide translocase 4 is expressed within embryonic ovaries and dispensable during oogenesis.

    Science.gov (United States)

    Lim, Chae Ho; Brower, Jeffrey V; Resnick, James L; Oh, S Paul; Terada, Naohiro

    2015-02-01

    Adenine nucleotide translocase (Ant) facilitates the exchange of adenosine triphosphate across the mitochondrial inner membrane and plays a critical role for bioenergetics in eukaryotes. Mice have 3 Ant paralogs, Ant1 (Slc25a4), Ant2 (Slc25a5), and Ant4 (Slc25a31), which are expressed in a tissue-dependent manner. We previously identified that Ant4 was expressed exclusively in testicular germ cells in adult mice and essential for spermatogenesis and subsequently male fertility. Further investigation into the process of spermatogenesis revealed that Ant4 was particularly highly expressed during meiotic prophase I and indispensable for normal progression of leptotene spermatocytes to the stages thereafter. In contrast, the expression and roles of Ant4 in female germ cells have not previously been elucidated. Here, we demonstrate that the Ant4 gene is expressed during embryonic ovarian development during which meiotic prophase I occurs. We confirmed embryonic ovary-specific Ant4 expression using a bacterial artificial chromosome transgene. In contrast to male, however, Ant4 null female mice were fertile although the litter size was slightly decreased. They showed apparently normal ovarian development which was morphologically indistinguishable from the control animals. These data indicate that Ant4 is a meiosis-specific gene expressed during both male and female gametogenesis however indispensable only during spermatogenesis and not oogenesis. The differential effects of Ant4 depletion within the processes of male and female gametogenesis may be explained by meiosis-specific inactivation of the X-linked Ant2 gene in male, a somatic paralog of the Ant4 gene. © The Author(s) 2014.

  4. Salt Specificity of a Reduced Nicotinamide Adenine Dinucleotide Oxidase Prepared from a Halophilic Bacterium1

    Science.gov (United States)

    Hochstein, L. I.; Dalton, B. P.

    1968-01-01

    Extracts prepared from a halophilic bacterium contained a reduced nicotinamide adenine dinucleotide (NADH2) oxidase active at high solute concentrations. The cation requirement was nonspecific, since KCl, RbCl, and CsCl replaced NaCl with little or no loss of activity, and NH4Cl was only partially effective. Only LiCl failed to replace NaCl. No specific chloride requirement was observed although not all anions replaced chloride. Bromide, nitrate, and iodide were essentially ineffective, whereas acetate, formate, citrate, and sulfate proved suitable. The presence of sulfate affected the ability of a cation to satisfy the solute requirement. Sulfate enhanced the rate of NADH2 oxidation when compared with the rate observed in the presence of chloride. Cations which were inactive as chlorides (LiCl and MgCl2 at high concentrations) satisfied the cation requirement when added as sulfate salts. Although magnesium satisfied the cation requirement, a concentration effect, as well as an anion effect, was observed. In the presence of MgCl2, little NADH2 oxidation was observed at concentrations greater than 1 m. At lower concentrations, the rate of oxidation increased, reaching a maximal value at 0.1 m and remaining constant up to a concentration of 0.05 m MgCl2. Magnesium acetate and MgSO4 also replaced NaCl, and the maximal rate of oxidation occurred at 0.05 m with respect to magnesium. There was no change in the rate of oxidation at high magnesium acetate concentrations, whereas the rate of NADH2 oxidation increased at higher concentrations of MgSO4. PMID:5636829

  5. Electrochemical oxidation of dihydronicotinamide adenine dinucleotide at nitrogen-doped carbon nanotube electrodes.

    Science.gov (United States)

    Goran, Jacob M; Favela, Carlos A; Stevenson, Keith J

    2013-10-01

    Nitrogen-doped carbon nanotubes (N-CNTs) substantially lower the overpotential necessary for dihydronicotinamide adenine dinucleotide (NADH) oxidation compared to nondoped CNTs or traditional carbon electrodes such as glassy carbon (GC). We observe a 370 mV shift in the peak potential (Ep) from GC to CNTs and another 170 mV shift from CNTs to 7.4 atom % N-CNTs in a sodium phosphate buffer solution (pH 7.0) with 2.0 mM NADH (scan rate 10 mV/s). The sensitivity of 7.4 atom % N-CNTs to NADH was measured at 0.30 ± 0.04 A M(-1) cm(-2), with a limit of detection at 1.1 ± 0.3 μM and a linear range of 70 ± 10 μM poised at a low potential of -0.32 V (vs Hg/Hg2SO4). NADH fouling, known to occur to the electrode surface during NADH oxidation, was investigated by measuring both the change in Ep and the resulting loss of electrode sensitivity. NADH degradation, known to occur in phosphate buffer, was characterized by absorbance at 340 nm and correlated with the loss of NADH electroactivity. N-CNTs are further demonstrated to be an effective platform for dehydrogenase-based biosensing by allowing glucose dehydrogenase to spontaneously adsorb onto the N-CNT surface and measuring the resulting electrode's sensitivity to glucose. The glucose biosensor had a sensitivity of 0.032 ± 0.003 A M(-1) cm(-2), a limit of detection at 6 ± 1 μM, and a linear range of 440 ± 50 μM.

  6. An alternative membrane transport pathway for phosphate and adenine nucleotides in mitochondria and its possible function

    Science.gov (United States)

    Reynafarje, Baltazar; Lehninger, Albert L.

    1978-01-01

    This paper describes the properties and a possible biological role of a transport process across the inner membrane of rat liver mitochondria resulting in the exchange of ATP4- (out) for ADP3- (in) + 0.5 phosphate2- (in). This transmembrane exchange reaction, designated as the ATP-ADP-phosphate exchange, is specific for the ligands shown, electroneutral, insensitive to N-ethylmaleimide or mersalyl, inhibited by atractyloside, and appears to occur only in the direction as written. It is thus distinct from the well-known phosphate-hydroxide and phosphate-dicarboxylate exchange systems, which are inhibited by mersalyl, and from the ATP-ADP exchanger, which does not transport phosphate. During ATP hydrolysis by mitochondria, half of the phosphate formed from ATP passes from the matrix to the medium by the mersalyl-insensitive ATP-ADP-phosphate exchange and the other half by the well-known mersalyl-sensitive phosphate-hydroxide exchange. These and other considerations have led to a hypothesis for the pathway and stoichiometry of ATP-dependent reverse electron transport, characterized by a requirement of 1.33 molecules of ATP per pair of electrons reversed and by the utilization of a different membrane transport pathway for phosphate and adenine nucleotides than is taken in forward electron flow and oxidative phosphorylation. The possible occurrence of independent pathways for ATP-forming forward electron flow and ATP-consuming reverse electron flow is consonant with the fact that the opposing degradative and synthetic pathways in the central routes of cell metabolism generally have different pathways that are independently regulated. PMID:283393

  7. Transgenic overexpression of adenine nucleotide translocase 1 protects ischemic hearts against oxidative stress.

    Science.gov (United States)

    Klumpe, Inga; Savvatis, Konstantinos; Westermann, Dirk; Tschöpe, Carsten; Rauch, Ursula; Landmesser, Ulf; Schultheiss, Heinz-Peter; Dörner, Andrea

    2016-06-01

    Ischemia impairs the adenine nucleotide translocase (ANT), which transports ADP and ATP across the inner mitochondrial membrane. We investigated whether ANT1 overexpression has protective effects on ischemic hearts. Myocardial infarction was induced in wild-type (WT) and heart-specific ANT1-transgenic (ANT1-TG) rats, and hypoxia was set in isolated cardiomyocytes. ANT1 overexpression reduced the myocardial infarct area and increased the survival rate of infarcted rats. Reduced ANT1 expression and increased 4-hydroxynonenal modification of ANT paralleled to impaired ANT function in infarcted WT hearts. ANT1 overexpression improved ANT expression and function. This was accompanied by reduced mitochondrial cytochrome C release and caspase-3 activation. ANT1-TG hearts suffered less from oxidative stress, as shown by lower protein carbonylation and 4-hydroxynonenal modification of ANT. ANT1 overexpression also increased cell survival of hypoxic cardiomyocytes and attenuated reactive oxygen species (ROS) production. This was linked to higher stability of mitochondrial membrane potential and lower activity of ROS detoxifying catalase. ANT1-TG cardiomyocytes also showed higher resistance against H2O2 treatment, which was independent of catalase activity. In conclusion, ANT1 overexpression compensates impaired ANT activity under oxygen-restricted conditions. It reduces ROS production and oxidative stress, stabilizes mitochondrial integrity, and increases survival, making ANT1 a component in ROS management and heart protection during ischemia. ANT1 overexpression reduces infarct size and increases survival after infarction. ANT1 overexpression compensates restricted ANT expression and function in infarcted hearts. Increased ANT1 expression enhances mitochondrial integrity. ANT1-overexpressing hearts reduce oxidative stress by decreasing ROS generation. ANT1 is a component in ROS management and heart protection.

  8. Single electron-ics with carbon nanotubes

    NARCIS (Netherlands)

    Götz, G.T.J.

    2010-01-01

    We experimentally investigate Quantum Dots, formed in Carbon Nanotubes. The first part of this thesis deals with charge sensing on such quantum dots. The charge sensor is a metallic Single-electron-transistor, sensitive to the charge of a single electron on the quantum dot. We use this technique for

  9. Improving the discovery potential of charged Higgs bosons at the ...

    Indian Academy of Sciences (India)

    The detection of charged Higgs bosons (H ¦) at Tevatron or the LHC would unequivocally imply the existence of physics beyond the standard model (SM), since spin-less charged scalar states do not belong to its particle spectrum. Singly charged Higgs bosons appear in any two-Higgs doublet model (2HDM), including a ...

  10. Migration and fate of charges initially produced in irradiated DNA: a review

    International Nuclear Information System (INIS)

    Faraggi, M.; Ferradini, C.; Jay-Gerin, J.P.

    1995-01-01

    It has been shown that the charges, electrons and 'holes', generated by the action of ionizing radiation on DNA, in the solid phase as well as in aqueous solution, can migrate along the DNA chain before being trapped. Electron migration distances are of the order of 100 base pairs (the inter-base pair distance being 3.4 A) in the first case, and about one order of magnitude smaller in the second case. Short-range hole migration processes seem to occur from the initial cation radicals to sites located predominantly at the purine bases [adenine (A) and guanine (G)], with guanine being the most favorable hole trapping center. This radical cation G +. may undergo charge recombination or lead to a reaction sequence susceptible to induce single-strand breaks. The electrons produced during the ionization processes seem to react preferentially with the pyrimidine bases [cytosine (C) and thymine (T)], with the formation of two anionic primary radicals, T -. . Based on thermodynamic and kinetic considerations about T -. , it seems that this latter is responsible for inducing single-strand breaks. When the electron is initially trapped by cytosine, a proton is transferred to C -. from the complementary guanine. The deprotonation of this guanine leads to a reduction potential decrease of 200 mV, creating an electron donor site G(-H) - . This site is susceptible to transfer an electron to a radical cation, or to its subsequent intermediates, located at a distance equal to, or less than the characteristic electron migration distance. A pair of coupled free radicals, derived from cytosine and guanine, namely, C(H) . and g(-H) . , may thus be produced. The possible reactions between these two radicals could lead to: (i) the reformation of C and G by recombination, (ii) the reaction of an interstrand covalent bond, and (iii) the induction of a double-strand break. These two latter processes may result in permanent damages of the DNA molecule. (authors). 97 refs., 6 figs., 3 tabs

  11. High-spin ferric ions in Saccharomyces cerevisiae vacuoles are reduced to the ferrous state during adenine-precursor detoxification.

    Science.gov (United States)

    Park, Jinkyu; McCormick, Sean P; Cockrell, Allison L; Chakrabarti, Mrinmoy; Lindahl, Paul A

    2014-06-24

    The majority of Fe in Fe-replete yeast cells is located in vacuoles. These acidic organelles store Fe for use under Fe-deficient conditions and they sequester it from other parts of the cell to avoid Fe-associated toxicity. Vacuolar Fe is predominantly in the form of one or more magnetically isolated nonheme high-spin (NHHS) Fe(III) complexes with polyphosphate-related ligands. Some Fe(III) oxyhydroxide nanoparticles may also be present in these organelles, perhaps in equilibrium with the NHHS Fe(III). Little is known regarding the chemical properties of vacuolar Fe. When grown on adenine-deficient medium (A↓), ADE2Δ strains of yeast such as W303 produce a toxic intermediate in the adenine biosynthetic pathway. This intermediate is conjugated with glutathione and shuttled into the vacuole for detoxification. The iron content of A↓ W303 cells was determined by Mössbauer and EPR spectroscopies. As they transitioned from exponential growth to stationary state, A↓ cells (supplemented with 40 μM Fe(III) citrate) accumulated two major NHHS Fe(II) species as the vacuolar NHHS Fe(III) species declined. This is evidence that vacuoles in A↓ cells are more reducing than those in adenine-sufficient cells. A↓ cells suffered less oxidative stress despite the abundance of NHHS Fe(II) complexes; such species typically promote Fenton chemistry. Most Fe in cells grown for 5 days with extra yeast-nitrogen-base, amino acids and bases in minimal medium was HS Fe(III) with insignificant amounts of nanoparticles. The vacuoles of these cells might be more acidic than normal and can accommodate high concentrations of HS Fe(III) species. Glucose levels and rapamycin (affecting the TOR system) affected cellular Fe content. This study illustrates the sensitivity of cellular Fe to changes in metabolism, redox state and pH. Such effects broaden our understanding of how Fe and overall cellular metabolism are integrated.

  12. Analyzing Nicotinamide Adenine Dinucleotide Phosphate Oxidase Activation in Aging and Vascular Amyloid Pathology

    Directory of Open Access Journals (Sweden)

    Helena Radbruch

    2017-07-01

    Full Text Available In aging individuals, both protective as well as regulatory immune functions are declining, resulting in an increased susceptibility to infections as well as to autoimmunity. Nicotinamide adenine dinucleotide phosphate (NADPH oxidase 2-deficiency in immune cell subsets has been shown to be associated with aging. Using intravital marker-free NAD(PH-fluorescence lifetime imaging, we have previously identified microglia/myeloid cells and astrocytes as main cellular sources of NADPH oxidase (NOX activity in the CNS during neuroinflammation, due to an overactivation of NOX. The overactivated NOX enzymes catalyze the massive production of the highly reactive O2−, which initiates in a chain reaction the overproduction of diverse reactive oxygen species (ROS. Age-dependent oxidative distress levels in the brain and their cellular sources are not known. Furthermore, it is unclear whether in age-dependent diseases oxidative distress is initiated by overproduction of ROS or by a decrease in antioxidant capacity, subsequently leading to neurodegeneration in the CNS. Here, we compare the activation level of NOX enzymes in the cerebral cortex of young and aged mice as well as in a model of vascular amyloid pathology. Despite the fact that a striking change in the morphology of microglia can be detected between young and aged individuals, we find comparable low-level NOX activation both in young and old mice. In contrast, aged mice with the human APPE693Q mutation, a model for cerebral amyloid angiopathy (CAA, displayed increased focal NOX overactivation in the brain cortex, especially in tissue areas around the vessels. Despite activated morphology in microglia, NOX overactivation was detected only in a small fraction of these cells, in contrast to other pathologies with overt inflammation as experimental autoimmune encephalomyelitis (EAE or glioblastoma. Similar to these pathologies, the astrocytes majorly contribute to the NOX overactivation in the brain

  13. Alkaline Phosphatase, Soluble Extracellular Adenine Nucleotides, and Adenosine Production after Infant Cardiopulmonary Bypass.

    Science.gov (United States)

    Davidson, Jesse A; Urban, Tracy; Tong, Suhong; Twite, Mark; Woodruff, Alan; Wischmeyer, Paul E; Klawitter, Jelena

    2016-01-01

    Decreased alkaline phosphatase activity after infant cardiac surgery is associated with increased post-operative cardiovascular support requirements. In adults undergoing coronary artery bypass grafting, alkaline phosphatase infusion may reduce inflammation. Mechanisms underlying these effects have not been explored but may include decreased conversion of extracellular adenine nucleotides to adenosine. 1) Evaluate the association between alkaline phosphatase activity and serum conversion of adenosine monophosphate to adenosine after infant cardiac surgery; 2) assess if inhibition/supplementation of serum alkaline phosphatase modulates this conversion. Pre/post-bypass serum samples were obtained from 75 infants alkaline phosphatase and CD73. Low and high concentration 13C5-adenosine monophosphate (simulating normal/stress concentrations) were used. Effects of alkaline phosphatase supplementation on adenosine monophosphate clearance were also assessed. Changes in serum alkaline phosphatase activity were strongly correlated with changes in 13C5-adenosine production with or without CD73 inhibition (r = 0.83; palkaline phosphatase activity (≤80 U/L) generated significantly less 13C5-adenosine, particularly in the presence of high concentration 13C5-adenosine monophosphate (10.4μmol/L vs 12.9μmol/L; p = 0.0004). Inhibition of alkaline phosphatase led to a marked decrease in 13C5-adenosine production (11.9μmol/L vs 2.7μmol/L; palkaline phosphatase or high dose bovine intestinal alkaline phosphatase doubled 13C5-adenosine monophosphate conversion to 13C5-adenosine (pAlkaline phosphatase represents the primary serum ectonucleotidase after infant cardiac surgery and low post-operative alkaline phosphatase activity leads to impaired capacity to clear adenosine monophosphate. AP supplementation improves serum clearance of adenosine monophosphate to adenosine. These findings represent a potential therapeutic mechanism for alkaline phosphatase infusion during cardiac

  14. Photorelaxation of imidazole and adenine via electron-driven proton transfer along H2O wires

    Czech Academy of Sciences Publication Activity Database

    Szabla, Rafal; Gora, R.W.; Janicki, M.; Šponer, Jiří

    2016-01-01

    Roč. 195, č. 2016 (2016), s. 237-251 E-ISSN 1364-5498 R&D Projects: GA ČR(CZ) GA14-12010S Institutional support: RVO:68081707 Keywords : excited-state deactivation * induced charge-transfer Subject RIV: BO - Biophysics

  15. DNA Bases Thymine and Adenine in Bio-Organic Light Emitting Diodes

    Science.gov (United States)

    2014-11-24

    nm also decreased performance, as a surplus of holes can be injected creating a charge imbalance and a reduction in current emission efficiency. The...application as high energy density capacitors . J. Appl. Phys. 115, 114108, doi:10.1063/1.4868339 (2014). 22.Heckman, E.M.,Hagen, J. A., Yaney, P. P., Grote, J

  16. Pengaruh Berbagai Konsentrasi Benzil Adenin dan Asam Naftalen Asetat pada Kultur In Vitro Singkong (Manihot Esculenta Crantz.)

    OpenAIRE

    Ardian, Ardian; Kresna, Kresna; Agustiansyah, Agustiansyah

    2012-01-01

    Propagation of cassava through in vitro culture is needed by farmers and agro industries to fulfill the need of the best and the newest clone as soon as after it is released by government. The objective of this research was to know the effects of the application of some concentrations of benzyl adenine and naphthalene acetic acid on in vitro growth and multiplication of micro-shoot of cassava. Explants used were one-node green cuttings of cassava, which were derived from cutting seedling. Thi...

  17. In vitro plant regeneration system for common bean (Phaseolus vulgaris): effect of N6-benzylaminopurine and adenine sulphate

    OpenAIRE

    Gatica Arias,Andrés M; Muñoz Valverde,Jenny; Ramírez Fonseca,Pilar; Valdez Melara,Marta

    2010-01-01

    A method for regeneration of the commercially important common bean (Phaseolus vulgaris ) using N6-benzylaminopurine(BAP) and adenine sulphate (AS) was established. Embryogenic axes of the Costa Rican common bean cultivars Bribrí, Brunca, Guaymí, Huetar and Telire were cultured on Murashige and Skoog medium supplemented with 100 mgl-1 myo-inositol, 1 mgl-1 thiamine, 30 gl-1 sucrose, BAP (0, 5 and 10 mgl-1), AS (0, 20 and 40 mgl-1) and 8 gl-1 agar. Regardless of the concentration of BAP and AS...

  18. Identification of malic enzyme mutants depending on 1,2,3-triazole moiety-containing nicotinamide adenine dinucleotide analogs.

    Science.gov (United States)

    Hou, Shuhua; Ji, Debin; Liu, Wujun; Wang, Lei; Zhao, Zongbao Kent

    2014-03-01

    An activity screening between 1,2,3-triazole moiety-containing nicotinamide adenine dinucleotide (NAD) analogs and malic enzyme (ME) mutants identified some mutants capable of taking NAD analogs as the cofactor. One particular pair, ME-L310K/L404S and the analog B-8 had good catalytic efficiency and cofactor specificity. The new system gained about 1200-fold cofactor specificity shift from NAD toward B-8 in terms of oxidative decarboxylation of l-malate. Our results provided insightful information for the development of orthogonal redox system that is of particular important to precisely control engineered metabolic pathways. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. Electronic Transport in Single-Stranded DNA Molecule Related to Huntington's Disease

    Science.gov (United States)

    Sarmento, R. G.; Silva, R. N. O.; Madeira, M. P.; Frazão, N. F.; Sousa, J. O.; Macedo-Filho, A.

    2018-04-01

    We report a numerical analysis of the electronic transport in single chain DNA molecule consisting of 182 nucleotides. The DNA chains studied were extracted from a segment of the human chromosome 4p16.3, which were modified by expansion of CAG (cytosine-adenine-guanine) triplet repeats to mimics Huntington's disease. The mutated DNA chains were connected between two platinum electrodes to analyze the relationship between charge propagation in the molecule and Huntington's disease. The computations were performed within a tight-binding model, together with a transfer matrix technique, to investigate the current-voltage (I-V) of 23 types of DNA sequence and compare them with the distributions of the related CAG repeat numbers with the disease. All DNA sequences studied have a characteristic behavior of a semiconductor. In addition, the results showed a direct correlation between the current-voltage curves and the distributions of the CAG repeat numbers, suggesting possible applications in the development of DNA-based biosensors for molecular diagnostics.

  20. Electronic Transport in Single-Stranded DNA Molecule Related to Huntington's Disease

    Science.gov (United States)

    Sarmento, R. G.; Silva, R. N. O.; Madeira, M. P.; Frazão, N. F.; Sousa, J. O.; Macedo-Filho, A.

    2018-02-01

    We report a numerical analysis of the electronic transport in single chain DNA molecule consisting of 182 nucleotides. The DNA chains studied were extracted from a segment of the human chromosome 4p16.3, which were modified by expansion of CAG (cytosine-adenine-guanine) triplet repeats to mimics Huntington's disease. The mutated DNA chains were connected between two platinum electrodes to analyze the relationship between charge propagation in the molecule and Huntington's disease. The computations were performed within a tight-binding model, together with a transfer matrix technique, to investigate the current-voltage (I-V) of 23 types of DNA sequence and compare them with the distributions of the related CAG repeat numbers with the disease. All DNA sequences studied have a characteristic behavior of a semiconductor. In addition, the results showed a direct correlation between the current-voltage curves and the distributions of the CAG repeat numbers, suggesting possible applications in the development of DNA-based biosensors for molecular diagnostics.

  1. Production, transport and charge capture measurements of highly charged recoil ions

    International Nuclear Information System (INIS)

    Trebus, U.E.

    1989-01-01

    An experiment is described to study highly charged recoil ions on-line to the heavy accelerator UNILAC at GSI. The highly charged recoil ions are produced by heavy-ion bombardment of a gas target. Subsequently the slow highly charged recoil ions are extracted from the ionization volume, and guided through a beam transport line to a Wien filter for charge state selection and to a collision region to study charge transfer processes. Several experiments were carried out to show the efficient charge state separation. Charge states up to q = 15 were observed. When using a retarding field analyzer cross sections for single electron capture were determined for different charge states of Xe q+ for q = 4 to 11 and He gas. The experiments demonstrated increasing charge transfer cross sections with increasing charge state q and indicated the effect of near resonant charge capture for q = 6. The flexible data acquisition system used, is described and other future experiments, such as for instance in flight ion-trapping are indicated in the appendix

  2. Linear shaped charge

    Energy Technology Data Exchange (ETDEWEB)

    Peterson, David; Stofleth, Jerome H.; Saul, Venner W.

    2017-07-11

    Linear shaped charges are described herein. In a general embodiment, the linear shaped charge has an explosive with an elongated arrowhead-shaped profile. The linear shaped charge also has and an elongated v-shaped liner that is inset into a recess of the explosive. Another linear shaped charge includes an explosive that is shaped as a star-shaped prism. Liners are inset into crevices of the explosive, where the explosive acts as a tamper.

  3. Charge Transport in Electrostatic Radiography.

    Science.gov (United States)

    Fallone, B. Gino

    A new analytical hyperbolic expression is presented to describe the full saturation curve of parallel-plate ionization chambers filled with air or with high atomic number gases at elevated pressures. It is shown that all parameters of the saturation curve expression can be calculated from one single measurement of ionization current at a given electric field and air gap thickness. Isothermal charge deposition on polymers to form stable foil electrets by using an apparatus resembling parallel-plate ionization chambers is reported. Charge carriers produced by irradiation of the sensitive air volume drift in the externally applied electric field and get trapped on the polymer surface to form electrets. The time dependence of the polarization and depolarization current densities, the effective electric field in the electret chamber, and the electret surface charge densities are presented for the radiation-induced foil electret and an excellent agreement is obtained with the measured electret data. The theory of linear systems is used to derive the electric field and potential in distance space in the electret chamber. The charging characteristics of ionographi latent images are discussed in terms of saturation characteristics of ionographic chambers. The minimum applied electric field needed for an optimized charge collection in the ionographic chamber is presented in terms of both the electret characteristic polarization time and the electret relaxation time. The feasibility of radiographic image subtraction based on electrostatic imaging techniques is demonstrated. Latent image charging at one polarity corresponding to the production of the primary image, and latent image discharging with the opposite chamber polarity, are used to create the final image representing the region of interest.

  4. Spacecraft Charging Technology, 1980

    Science.gov (United States)

    1981-01-01

    The third Spacecraft Charging Technology Conference proceedings contain 66 papers on the geosynchronous plasma environment, spacecraft modeling, charged particle environment interactions with spacecraft, spacecraft materials characterization, and satellite design and testing. The proceedings is a compilation of the state of the art of spacecraft charging and environmental interaction phenomena.

  5. Effects of High Levels of DNA Adenine Methylation on Methyl-Directed Mismatch Repair in ESCHERICHIA COLI

    Science.gov (United States)

    Pukkila, Patricia J.; Peterson, Janet; Herman, Gail; Modrich, Paul; Meselson, Matthew

    1983-01-01

    Two methods were used in an attempt to increase the efficiency and strand selectivity of methyl-directed mismatch repair of bacteriophage λ heteroduplexes in E. coli. Previous studies of such repair used λ DNA that was only partially methylated as the source of methylated chains. Also, transfection was carried out in methylating strains. Either of these factors might have been responsible for the incompleteness of the strand selectivity observed previously. In the first approach to increasing strand selectivity, heteroduplexes were transfected into a host deficient in methylation, but no changes in repair frequencies were observed. In the second approach, heteroduplexes were prepared using DNA that had been highly methylated in vitro with purified DNA adenine methylase as the source of methylated chains. In heteroduplexes having a repairable cI/+ mismatch, strand selectivity was indeed enhanced. In heteroduplexes with one chain highly methylated and the complementary chain unmethylated, the frequency of repair on the unmethylated chain increased to nearly 100%. Heteroduplexes with both chains highly methylated were not repaired at a detectable frequency. Thus, chains highly methylated by DNA adenine methylase were refractory to mismatch repair by this system, regardless of the methylation of the complementary chain. These results support the hypothesis that methyl-directed mismatch repair acts to correct errors of replication, thus lowering the mutation rate. PMID:6225697

  6. Kinetic and thermodynamic study of the reaction catalyzed by glucose-6-phosphate dehydrogenase with nicotinamide adenine dinucleotide

    International Nuclear Information System (INIS)

    Martin del Campo, Julia S.; Patino, Rodrigo

    2011-01-01

    Research highlights: → The reaction catalyzed by one enzyme of the pentose phosphate pathway was studied. → A spectrophotometric method is proposed for kinetic and thermodynamic analysis. → The pH and the temperature influences are reported on physical chemical properties. → Relative concentrations of substrates are also important in the catalytic process. - Abstract: The enzyme glucose-6-phosphate dehydrogenase (G6PD, EC 1.1.1.49) from Leuconostoc mesenteroides has a dual coenzyme specificity with oxidized nicotinamide adenine dinucleotide (NAD ox ) and oxidized nicotinamide adenine dinucleotide phosphate as electron acceptors. The G6PD coenzyme selection is determined by the metabolic cellular prevailing conditions. In this study a kinetic and thermodynamic analysis is presented for the reaction catalyzed by G6PD from L. mesenteroides with NAD ox as coenzyme in phosphate buffer. For this work, an in situ spectrophotometric technique was employed based on the detection of one product of the reaction. Substrate and coenzyme concentrations as well as temperature and pH effects were evaluated. The apparent equilibrium constant, the Michaelis constant, and the turnover number were determined as a function of each experimental condition. The standard transformed Gibbs energy of reaction was determined from equilibrium constants at different initial conditions. For the product 6-phospho-D-glucono-1,5-lactone, a value of the standard Gibbs energy of formation is proposed, Δ f G o = -1784 ± 5 kJ mol -1 .

  7. Evaluation of Porin Interaction with Adenine Nucleotide Translocase and Cyclophilin-D Proteins after Brain Ischemia and Reperfusion

    Directory of Open Access Journals (Sweden)

    Mohammad Ali Atlasi

    2011-01-01

    Full Text Available Objective (s Porin is a mitochondrial outer membrane channel, which usually functions as the pathway for the movement of various substances in and out of the mitochondria and is considered to be a component of the permeability transition (PT pore complex that plays a role in the PT. We addressed the hypothesis that porin interacts with other mitochondrial proteins after ischemic injury.Materials and MethodsFor this purpose, we used in vivo 4-vessel occlusion model of rat brain and porin purification method by hydroxyapatite column. After SDS gel electrophoresis and silver nitrate staining, Western blotting was done for porin, adenine nucleotide translocase and cyclophilin-D proteins.Results Porin was purified from mitochondrial mixture in ischemic brain and control groups. Investigation of interaction of adenine nucleotide transposes (ANT and cyclophilin-D with porin by Western blotting showed no proteins co-purified with porin from injured tissues.Conclusion The present study implies that there may not be interaction between porin, and ANT or cyclophilin-D, and if there is any, it is not maintained during the purification procedure.

  8. Characterization of a DNA Adenine Methyltransferase Gene of Borrelia hermsii and Its Dispensability for Murine Infection and Persistence.

    Science.gov (United States)

    James, Allison E; Rogovskyy, Artem S; Crowley, Michael A; Bankhead, Troy

    2016-01-01

    DNA methyltransferases have been implicated in the regulation of virulence genes in a number of pathogens. Relapsing fever Borrelia species harbor a conserved, putative DNA methyltransferase gene on their chromosome, while no such ortholog can be found in the annotated genome of the Lyme disease agent, Borrelia burgdorferi. In the relapsing fever species Borrelia hermsii, the locus bh0463A encodes this putative DNA adenine methyltransferase (dam). To verify the function of the BH0463A protein product as a Dam, the gene was cloned into a Dam-deficient strain of Escherichia coli. Restriction fragment analysis subsequently demonstrated that complementation of this E. coli mutant with bh0463A restored adenine methylation, verifying bh0463A as a Dam. The requirement of bh0463A for B. hermsii viability, infectivity, and persistence was then investigated by genetically disrupting the gene. The dam- mutant was capable of infecting immunocompetent mice, and the mean level of spirochetemia in immunocompetent mice was not significantly different from wild type B. hermsii. Collectively, the data indicate that dam is dispensable for B. hermsii viability, infectivity, and persistence.

  9. Charged particle detector

    International Nuclear Information System (INIS)

    Hagen, R.D.

    1975-01-01

    A device for detecting the emission of charged particles from a specimen is described. The specimen is placed within an accumulator means which statically accumulates any charged particles emitted from the specimen. The accumulator means is pivotally positioned between a first capacitor plate having a positive electrical charge and a second capacitor plate having a negative electrical charge. The accumulator means is attracted to one capacitor plate and repelled from the other capacitor plate by an amount proportional to the amount and intensity of charged particles emitted by the specimen. (auth)

  10. Space Charge Effects

    CERN Document Server

    Ferrario, M.; Palumbo, L.

    2014-12-19

    The space charge forces are those generated directly by the charge distribution, with the inclusion of the image charges and currents due to the interaction of the beam with a perfectly conducting smooth pipe. Space charge forces are responsible for several unwanted phenomena related to beam dynamics, such as energy loss, shift of the synchronous phase and frequency , shift of the betatron frequencies, and instabilities. We will discuss in this lecture the main feature of space charge effects in high-energy storage rings as well as in low-energy linacs and transport lines.

  11. Adenine sulfate effect on shoot formation of Phaseolus vulgaris L. cultivar `CIAP7247F' via indirect organogenesis

    OpenAIRE

    Novisel Veitía; Lourdes R García; Amanda Martirena Ramírez; Idalmis Bermúdez Caraballoso; Raúl Collado; Damaris Torres; Carlos Romero

    2015-01-01

    This study aimed to determine the effect of adenine sulfate in plant regeneration from callus of Phaseolus vulgaris L. cultivar `CIAP 7247F'. To this, it was added two concentrations (20 and 40 mg l-1) adenine sulfate to the regeneration culture medium and it was included a control to form a total of three treatments. The number of formed shoots was quantified by treatment in the regeneration culture medium and the height of shoot was measured in elongation medium. It was determined that the ...

  12. Genotype-dependent variability in flow cytometric evaluation of reduced nicotinamide adenine dinucleotide phosphate oxidase function in patients with chronic granulomatous disease.

    Science.gov (United States)

    Vowells, S J; Fleisher, T A; Sekhsaria, S; Alling, D W; Maguire, T E; Malech, H L

    1996-01-01

    We studied phagocyte reduced nicotinamide adenine dinucleotide phosphate function to evaluate production of reactive oxygen species in both X-linked and autosomal forms of chronic granulomatous disease. We found a consistent and significant difference between the activated granulocyte response of the X-linked (gp91-phagocyte oxidase) form of chronic granulomatous disease (n = 18) and that of the most common autosomal recessive (p47-phagocyte oxidase) form of the disease (n = 17). The data indicate that mutations in the p47-phagocyte oxidase component of the reduced nicotinamide adenine dinucleotide phosphate oxidase component do not completely prevent oxidation despite severe defects in superoxide generation.

  13. ABC's of pion charge exchange

    International Nuclear Information System (INIS)

    Gibbs, W.R.; Kaufmann, W.B.; Siegel, P.B.

    1985-01-01

    Calculations of pion single charge exchange using the PWIA and DWIA are presented. Emphasis is given to the effects of absorbtion and blocking. A microscopic calculation of the 0 0 excitation and low energy angular distribution is in excellent agreement with the data. A fixed nucleon multiple scattering calculation of the pion double charge exchange reaction is presented. Various valence neutron wave functions are used, and the contributions of different spatial orientations of the last two neutrons to the reaction are examined. The DCX cross section is found to be very sensitive to the inclusion of correlations in the two-neutron wave function. Satisfactory agreement with DCX data on 14 C can be obtained using a nucleonic picture of the nucleus

  14. A method for charging a test carrier and a test carrier

    DEFF Research Database (Denmark)

    2014-01-01

    A method of charging a substrate with a plurality of through-going bores and a charged substrate, where the substrate is charged with a liquid comprising particles in a concentration resulting in a high percentage of bores charged with liquid with only a single particle therein....

  15. Contractor Software Charges

    National Research Council Canada - National Science Library

    Granetto, Paul

    1994-01-01

    .... Examples of computer software costs that contractors charge through indirect rates are material management systems, security systems, labor accounting systems, and computer-aided design and manufacturing...

  16. A Search for Free Fractional Electric Charge Elementary Particles

    Energy Technology Data Exchange (ETDEWEB)

    Halyo, Valerie

    2000-12-04

    A direct search was carried out in bulk matter for free fractional electric charge elementary particles using the largest mass single sample ever studied--about 17.4 mg of silicone oil. The search used an improved and highly automated Millikan oil drop technique. No evidence for fractional charge particles was found. The concentration of particles with fractional charge more than 0.16 e (e being the magnitude of the electron charge) from the nearest integer charge is less than 4.71 x 10{sup -22} particles per nucleon with 95% confidence.

  17. A Search for Free Fractional Electric Charge Elementary Particles

    Energy Technology Data Exchange (ETDEWEB)

    Halyo, Valerie

    2000-12-04

    A direct search was carried out in bulk matter for free fractional electric charge elementary particles using the largest mass single sample ever studied| about 17.4 mg of silicone oil. The search used an improved and highly automated Millikan oil drop technique. No evidence for fractional charge particles was found. The concentration of particles with fractional charge more than 0.16 e (e being the magnitude of the electron charge) from the nearest integer charge is less than 4.71 x 10{sup -22} particles per nucleon with 95% confidence.

  18. Evidence of Space-Charge Effects in Thermal Poling

    DEFF Research Database (Denmark)

    Wu, X.; Arentoft, Jesper; Wong, D.

    1999-01-01

    The in situ thermal poling processes in germanosilicate fibers for positive and negative poling voltages are significantly different. Thermal poling of silica fibers consists of two processes: the faster linear process of charge migration and the subsequent single exponential process of charge...... ionization. Both the shielding electrical field due to charge migration and the ionization electrical field due to charge ionization are able to be frozen-in at room temperature acid lead to the residual linear electrooptic effects, The observations support that the mechanism of the induced electrooptic...... effects is based on space charge electrical fields instead of dipole/bond orientation....

  19. Isolation of adenine salts in the gas phase from a liquid beam of aqueous solutions by IR laser irradiation

    Science.gov (United States)

    Kohno, J.-Y.; Mafuné, F.; Kondow, T.

    2002-09-01

    A continuous liquid flow in a vacuum (a liquid beam) of an aqueous solution of adenine salt containing hydrochloric acid or sodium hydroxide was irradiated with an intense pulsed IR laser at 3 μm, which is resonant to a vibrational mode related to the OH stretch vibration of H2O. Neutral species isolated into the vacuum were ionized by a pulsed UV laser at 270 nm, and the product ions were mass-analyzed by a time-of-flight mass spectrometer. It is found that AH2^{2+}{\\cdot}2Cl^- and [ A iH] ^{i-}{\\cdot} iNa^+ (i=1 3) are isolated in the vacuum from the aqueous acidic and alkaline solutions, respectively, under irradiation of the IR laser, and undergo four-photon ionization involving decomposition and proton transfer of the intermediate species under irradiation of the UV laser.

  20. Effect of gamma radiation on levels of adenine nucleotides in erythrocytes of healthy individuals after submaximum physical exertion

    International Nuclear Information System (INIS)

    Zagorski, T.; Dudek, I.; Mazurek, M.; Berkan, L.; Chmielewski, H.; Kedziora, J.

    1994-01-01

    The authors studied the effect of gamma radiation and submaximum physical exercise on adenosine-5'-triphosphate (ATP), adenosine-5'-diphosphate (ADP) and adenosine-5'-monophosphate (AMP) contents in erythrocytes of healthy males. Twenty one men aged 20-22 years were examined. They underwent physical exercise at doses of 2 w/kg body weight for 15 min. Erythrocytes were exposed to gamma radiation (500 Gy doses) from 60 Co source. The concentration of adenine nucleotides in erythrocytes was measured by the Boehringer Mannheim tests. The submaximum physical exercise was found to decrease ATP content and to increase ADP and AMP in erythrocytes. Gamma radiation at 500 Gy dose was found to decrease ATP concentration in erythrocytes both at rest and after submaximum exercise and to increase AD content. It was revealed that AMP content increased at rest and decreased after submaximum exercise in irradiated erythrocytes. (author). 20 refs, 1 tab

  1. Function of Ubiquinone in Electron Transport from Reduced Nicotinamide Adenine Dinucleotide to Nitrate and Oxygen in Aerobacter aerogenes

    Science.gov (United States)

    Knook, D. L.; Planta, R. J.

    1971-01-01

    The possible role of quinones in the electron transport system of Aerobacter aerogenes was investigated. The only quinone found in measurable amounts in bacteria grown in minimal media under both aerobic and anaerobic conditions was ubiquinone-8. Membrane-bound ubiquinone-8 could be removed by extraction with pentane, or destroyed by ultraviolet irradiation, with a concomitant loss of both reduced nicotinamide adenine dinucleotide (NADH) oxidase and NADH-linked respiratory nitrate reductase activity. In the extracted membrane preparations, these enzymatic activities could be restored, both to the same degree, by incorporation of ubiquinone-6, -8, or -10, but not by incorporation of menaquinones. The NADH oxidation and the nitrate reduction were sensitive to the respiratory inhibitors dicoumarol, lapachol, and cyanide. The results obtained indicate that ubiquinone-8 mediates the electron transport between NADH and oxygen as well as between NADH and nitrate. Branching of the electron transport chain to oxygen and nitrate occurs after an initial common pathway. PMID:4100202

  2. Simultaneous quantitation of nicotinamide riboside, nicotinamide mononucleotide and nicotinamide adenine dinucleotide in milk by a novel enzyme-coupled assay.

    Science.gov (United States)

    Ummarino, Simone; Mozzon, Massimo; Zamporlini, Federica; Amici, Adolfo; Mazzola, Francesca; Orsomando, Giuseppe; Ruggieri, Silverio; Raffaelli, Nadia

    2017-04-15

    Nicotinamide riboside, the most recently discovered form of vitamin B3, and its phosphorylated form nicotinamide mononucleotide, have been shown to be potent supplements boosting intracellular nicotinamide adenine dinucleotide (NAD) levels, thus preventing or ameliorating metabolic and mitochondrial diseases in mouse models. Here we report for the first time on the simultaneous quantitation of nicotinamide riboside, nicotinamide mononucleotide and NAD in milk by means of a fluorometric, enzyme-coupled assay. Application of this assay to milk from different species revealed that the three vitamers were present in human and donkey milk, while being selectively distributed in the other milks. Human milk was the richest source of nicotinamide mononucleotide. Overall, the three vitamers accounted for a significant fraction of total vitamin B3 content. Pasteurization did not affect the bovine milk content of nicotinamide riboside, whereas UHT processing fully destroyed the vitamin. In human milk, NAD levels were significantly affected by the lactation time. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Effects of low-molecular-weight-chitosan on the adenine-induced chronic renal failure rats in vitro and in vivo

    Science.gov (United States)

    Zhi, Xuan; Han, Baoqin; Sui, Xianxian; Hu, Rui; Liu, Wanshun

    2015-02-01

    The effects of low-molecular-weight-chitosan (LMWC) on chronic renal failure (CRF) rats induced by adenine were investigated in vivo and in vitro. Chitosan were hydrolyzed using chitosanase at pH 6-7 and 37° for 24 h to obtain LMWC. In vitro, the effect of LMWC on the proliferation of renal tubular epithelial cells (RTEC) showed that it had no cytotoxic effect and could promote cell growth. For the in vivo experiment, chronic renal failure rats induced by adenine were randomly divided into control group, Niaoduqing group, and high-, medium- and low-dose LMWC groups. For each group, we detected serum creatinine (SCR), blood urea nitrogen (BUN), and total superoxide dismutase (T-SOD), glutathione oxidase (GSH-Px) activities of renal tissue, and obtained the ratio of kidney weight/body weight, pathological changes of kidney. The levels of serum SCR, BUN were higher in the adenine-induced rats than those in the control group, indicating that the rat chronic renal failure model worked successfully. The results after treatment showed that LMWC could reduce the SCR and BUN levels and enhance the activities/levels of T-SOD and GSH-PX in kidney compared to control group. Histopathological examination revealed that adenine-induced renal alterations were restored by LMWC at three tested dosages, especially at the low dosage of 100 mg kg-1 d-1.

  4. Effect of aqueous extract and anthocyanins of calyces of Hibiscus sabdariffa (Malvaceae) in rats with adenine-induced chronic kidney disease.

    Science.gov (United States)

    Ali, Badreldin H; Cahliková, Lucie; Opletal, Lubomir; Karaca, Turan; Manoj, Priyadarsini; Ramkumar, Aishwarya; Al Suleimani, Yousuf M; Al Za'abi, Mohammed; Nemmar, Abderrahim; Chocholousova-Havlikova, Lucie; Locarek, Miroslav; Siatka, Tomas; Blunden, Gerald

    2017-09-01

    The aim of this work was to assess the possible beneficial effects of aqueous extracts of Hibiscus sabdariffa L. calyces and anthocyanins isolated therefrom in an adenine-induced chronic kidney disease (CKD) model. Rats were orally given, for 28 consecutive days, either adenine alone or together with either aqueous extract of H. sabdariffa calyces (5 and 10%) or anthocyanins (50, 100 and 200 mg/kg of anthocyanin concentrate). For comparative purposes, two groups of rats were given lisinopril (10 mg/kg). When either H. sabdariffa aqueous extract or the anthocyanins isolated from it was administered along with adenine, the adverse effects of adenine-induced CKD were significantly lessened, mostly in a dose-dependent manner. The positive effects were similar to those obtained by administration of lisinopril. The results obtained show that both H. sabdariffa and its anthocyanins could be considered as possible promising safe dietary agents that could be used to attenuate the progression of human CKD. This could have added significance as H. sabdariffa tea is widely consumed in many parts of Africa and Asia and is thus readily available. © 2017 Royal Pharmaceutical Society.

  5. Application of elimination voltammetry to the resolution of adenine and cytosine signals in oligonucleotides. I. Homooligodeoxynucleotides dA9 and dC9

    Czech Academy of Sciences Publication Activity Database

    Trnková, L.; Jelen, František; Postbieglová, Irena

    2003-01-01

    Roč. 15, č. 19 (2003), s. 1529-1535 ISSN 1040-0397 R&D Projects: GA AV ČR IAA1163201; GA ČR GA203/02/0422 Institutional research plan: CEZ:AV0Z5004920 Keywords : adenine * cytosine * oligonucleotides Subject RIV: BO - Biophysics Impact factor: 1.811, year: 2003

  6. Charge Screening in a Charged Condensate

    International Nuclear Information System (INIS)

    Gabadadze, Gregory; Rosen, Rachel A.

    2009-01-01

    We consider a highly dense system of helium-4 nuclei and electrons in which the helium-4 nuclei have condensed. We present the condensation mechanism in the framework of low energy effective field theory and discuss the screening of electric charge in the condensate.

  7. Surface Charging and Points of Zero Charge

    CERN Document Server

    Kosmulski, Marek

    2009-01-01

    Presents Points of Zero Charge data on well-defined specimen of materials sorted by trademark, manufacturer, and location. This text emphasizes the comparison between particular results obtained for different portions of the same or very similar material and synthesizes the information published in research reports over the past few decades

  8. Slow charge movement in mammalian skeletal muscle.

    Science.gov (United States)

    Simon, B J; Beam, K G

    1985-01-01

    Voltage-dependent charge movements were measured in the rat omohyoid muscle with the three-microelectrode voltage-clamp technique. Contraction was abolished with hypertonic sucrose. The standard (ON-OFF) protocol for eliciting charge movements was to depolarize the fiber from -90 mV to a variable test potential (V) and then repolarize the fiber to -90 mV. The quantity of charge moved saturated at test potentials of approximately 0 mV. The steady state dependence of the amount of charge that moves as a function of test potential could be well fitted by the Boltzmann relation: Q = Qmax/(1 + exp[-(V - V)/k]), where Qmax is the maximum charge that can be moved, V is the potential at which half the charge moves, and k is a constant. At 15 degrees C, these values were Qmax = 28.5 nC/microF, V = -34.2 mV, and k = 8.7 mV. Qmax, k, and V exhibited little temperature dependence over the range 7-25 degrees C. "Stepped OFF" charge movements were elicited by depolarizing the fiber from -90 mV to a fixed conditioning level that moved nearly all the mobile charge (0 mV), and then repolarizing the fiber to varying test potentials. The sum of the charge that moved when the fiber was depolarized directly from -90 mV to a given test potential and the stepped OFF charge that moved when the fiber was repolarized to the same test potential had at all test potentials a value close to Qmax for that fiber. In nearly all cases, the decay phase of ON, OFF, and stepped OFF charge movements could be well fitted with a single exponential. The time constant, tau decay, for an ON charge movement at a given test potential was comparable to tau decay for a stepped OFF charge movement at the same test potential. Tau decay had a bell-shaped dependence on membrane potential: it was slowest at a potential near V (the midpoint of the steady state charge distribution) and became symmetrically faster on either side of this potential. Raising the temperature from 7 to 15 degrees C caused tau decay to

  9. Unilateral CHARGE association

    NARCIS (Netherlands)

    Trip, J; van Stuijvenberg, M; Dikkers, FG; Pijnenburg, MWH

    A case with a predominantly unilateral CHARGE association is reported. The CHARGE association refers to a combination of congenital malformations. This boy had left-sided anomalies consisting of choanal atresia. coloboma and peripheral facial palsy. The infant had a frontal encephalocele. an anomaly

  10. {8-14C}-Adenine and {1-14C}-isopentenyl pyrophosphate - precursors for root-produced cytokinins in the tomato (Lycopersicon esculentum mill.)

    International Nuclear Information System (INIS)

    Dickinson, J.R.

    1985-01-01

    Following the detection of reasonable levels of biologically active cytokinin-like compounds in one-month-old tomato plants, the possible involvement of {8- 14 C}-adenine and {1- 14 C}-isopentenyl pyrophosphate in the biosynthetic pathway leading to an accumulation of free zeatin derivatives, was studied. Intact tomato plants were used for a time-course study involving the uptake of {8- 14 C}-adenine and the tentative identification of compounds into which the 14 C became incorporated. Using high performance liquid chromatography, radioactive trans-zeatin was identified as being present in the Dowex 50 root extract. The 12-hour time interval was used and the roots of the tomato plants were immersed in a more heavily radiolabelled medium. Modified separation techniques were used to achieve enhanced radioactivity recovery rates. This experiment demonstrated the presence of relatively high levels of tentatively identified radioactive zeatin in the Dowex 50 root and stem extracts. Radioactivity in the aqueous extracts was found not to be contributed by cytokinin nucleotides. A final experiment was carried out using decapitated root systems to determine if the root tissue alone could be implicated in the synthesis of cytokinins. Decapitated tomato root systems were supplied with either {8- 14 C}-adenine or {1- 14 C}-isopentenyl pyrophosphate. The ratio of incorporation of {1- 14 C}-isopentenyl pyrophosphate into identified cytokinins was higher than for {8- 14 C}-adenine. It was concluded that both adenine and isopentenyl pyrophosphate are involved in the biosynthetic pathway leading to an accumulation of free zeatin derivatives in tomato roots

  11. Hole hopping rates in single strand oligonucleotides

    Energy Technology Data Exchange (ETDEWEB)

    Borrelli, Raffaele [Dipartimento di Scienze Agrarie, Forestali e Alimentari, Università di Torino, Largo Paolo Braccini 2, I-10095 Grugliasco, TO (Italy); Capobianco, Amedeo [Dipartimento di Chimica e Biologia, Università di Salerno, Via Giovanni Paolo II, I-84084 Fisciano, SA (Italy); Peluso, Andrea, E-mail: apeluso@unisa.it [Dipartimento di Chimica e Biologia, Università di Salerno, Via Giovanni Paolo II, I-84084 Fisciano, SA (Italy)

    2014-08-31

    Highlights: • DNA hole transfer rates have been computed. • Delocalized adenine domains significantly affect hole transfer rates in DNA. • Franck–Condon weighted density of state from DFT normal modes. • DNA application in molecular electronics. - Abstract: The rates of hole transfer between guanine and adenine in single strand DNA have been evaluated by using Fermi’s golden rule and Kubo’s generating function approach for the Franck–Condon weighted density of states. The whole sets of the normal modes and vibrational frequencies of the two nucleobases, obtained at DFT/B3LYP level of calculation, have been considered in computations. The results show that in single strand the pyramidalization/planarization mode of the amino groups of both nucleobases plays the major role. At room temperature, the Franck–Condon density of states extends over a wide range of hole site energy difference, 0–1 eV, giving some hints about the design of oligonucleotides of potential technological interest.

  12. Charging a Capacitor with a Photovoltaic Module

    Science.gov (United States)

    Aguilar, Horacio Munguía; Maldonado, Rigoberto Franco; Navarro, Luis Barba

    2017-01-01

    Charging a capacitor with a photovoltaic module is an experiment which reveals a lot about the modules characteristics. It is customary to represent these characteristics with an equivalent circuit whose elements represent its physical parameters. The behavior of a photovoltaic module is very similar to that of a single cell but the electric…

  13. Selective Coherent Excitation of Charged Density Waves

    NARCIS (Netherlands)

    Tsvetkov, A.A.; Sagar, D.M.; Loosdrecht, P.H.M. van; Marel, D. van der

    2003-01-01

    Real time femtosecond pump-probe spectroscopy is used to study collective and single particle excitations in the charge density wave state of the quasi-1D metal, blue bronze. Along with the previously observed collective amplitudon excitation, the spectra show several additional coherent features.

  14. Charge Storage, Conductivity and Charge Profiles of Insulators As Related to Spacecraft Charging

    OpenAIRE

    Dennison, JR; Frederickson, A. R.; Swaminathan, Prasanna

    2003-01-01

    Dissipation of charges built up near the surface of insulators due to space environment interaction is central to understanding spacecraft charging. Conductivity of insulating materials is key to determine how accumulated charge will distribute across the spacecraft and how rapidly charge imbalance will dissipate. To understand these processes requires knowledge of how charge is deposited within the insulator, the mechanisms for charge trapping and charge transport within the insulator, and h...

  15. Disorder- and correlation-induced charge carriers localization in oxyborate MgFeBO{sub 4}, Mg{sub 0.5}Co{sub 0.5}FeBO{sub 4}, CoFeBO{sub 4} single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Knyazev, Yu.V. [Siberian Federal University, 660074 Krasnoyarsk (Russian Federation); Kazak, N.V., E-mail: nat@iph.krasn.ru [Kirensky Institute of Physics, 660036 Krasnoyarsk (Russian Federation); Platunov, M.S. [Kirensky Institute of Physics, 660036 Krasnoyarsk (Russian Federation); Ivanova, N.B. [Siberian Federal University, 660074 Krasnoyarsk (Russian Federation); Bezmaternykh, L.N. [Kirensky Institute of Physics, 660036 Krasnoyarsk (Russian Federation); Arauzo, A. [Servicio de Medidas Físicas, Universidad de Zaragoza, 50009 Zaragoza (Spain); Bartolomé, J. [Instituto de Ciencia de Materiales de Aragón, CSIC-Universidad de Zaragoza and Departamento de Física de la Materia Condensada, 50009 Zaragoza (Spain); Ovchinnikov, S.G. [Siberian Federal University, 660074 Krasnoyarsk (Russian Federation); Kirensky Institute of Physics, 660036 Krasnoyarsk (Russian Federation); Siberian State Aerospace University, 660014 Krasnoyarsk (Russian Federation)

    2015-09-05

    Highlights: • The electrical resistance of the single crystalline warwickites has been measured. • The temperature-induced changes in the charge transfer mechanisms have been found. • The microscopic parameters of the electronic structure have been determined. • The studied warwickites have been classified as disordered correlated systems. • The Co substitution was found to lead to the weakening of the localization. - Abstract: The temperature dependence of the resistivity of single crystalline Mg{sub 1−x}Co{sub x}FeBO{sub 4} samples with x = 0.0, 0.5, 1.0 is investigated for the temperature range (210–400 K). The conduction was found to be governed by Mott variable-range hopping (VRH) in the low-temperature range (T = 210–270 K) and by thermo-activation mechanism in the high-temperature range (T = 280–400 K). Microscopic electronic parameters, such as the density of the localized states near the Fermi level, localization length, the hopping length, and the activation energy have been obtained. The change of the activation energy observed at high-temperature range was attributed to local structure distortions around Fe and Co atoms. The complicated behavior of charge transfer mechanisms is discussed based on two approaches: atomic disorder and electron correlations.

  16. Charge diffusion and the butterfly effect in striped holographic matter

    Energy Technology Data Exchange (ETDEWEB)

    Lucas, Andrew [Department of Physics, Harvard University,Cambridge, MA 02138 (United States); Department of Physics, Stanford University,Stanford, CA 94305 (United States); Steinberg, Julia [Department of Physics, Harvard University,Cambridge, MA 02138 (United States)

    2016-10-26

    Recently, it has been proposed that the butterfly velocity — a speed at which quantum information propagates — may provide a fundamental bound on diffusion constants in dirty incoherent metals. We analytically compute the charge diffusion constant and the butterfly velocity in charge-neutral holographic matter with long wavelength “hydrodynamic' disorder in a single spatial direction. In this limit, we find that the butterfly velocity does not set a sharp lower bound for the charge diffusion constant.

  17. Inclusive cross sections for pairs of identified light charged hadrons and for single protons in e+e at s=10.58GeV

    Energy Technology Data Exchange (ETDEWEB)

    Seidl, R.; Abdesselam, A.; Adachi, I.; Aihara, H.; Al Said, S.; Asner, D. M.; Aushev, T.; Ayad, R.; Babu, V.; Badhrees, I.; Bakich, A. M.; Barberio, E.; Bhardwaj, V.; Bhuyan, B.; Biswal, J.; Bozek, A.; Bračko, M.; Browder, T. E.; Červenkov, D.; Chekelian, V.; Chen, A.; Cheon, B. G.; Chilikin, K.; Cho, K.; Chobanova, V.; Choi, Y.; Cinabro, D.; Dalseno, J.; Dash, N.; Dingfelder, J.; Doležal, Z.; Drásal, Z.; Dutta, D.; Eidelman, S.; Farhat, H.; Fast, J. E.; Ferber, T.; Fulsom, B. G.; Gaur, V.; Gabyshev, N.; Garmash, A.; Gillard, R.; Giordano, F.; Goh, Y. M.; Goldenzweig, P.; Golob, B.; Haba, J.; Hara, T.; Hayasaka, K.; Hayashii, H.; He, X. H.; Hou, W. -S.; Hsu, C. -L.; Iijima, T.; Inami, K.; Ishikawa, A.; Itoh, R.; Iwasaki, Y.; Jacobs, W. W.; Jaegle, I.; Joffe, D.; Joo, K. K.; Kang, K. H.; Kato, E.; Katrenko, P.; Kawasaki, T.; Kim, D. Y.; Kim, H. J.; Kim, J. B.; Kim, J. H.; Kim, K. T.; Kim, M. J.; Kim, S. H.; Kim, Y. J.; Kodyš, P.; Korpar, S.; Križan, P.; Krokovny, P.; Kuzmin, A.; Kwon, Y. -J.; Lange, J. S.; Lee, D. H.; Li, L.; Li Gioi, L.; Libby, J.; Liu, Y.; Liventsev, D.; Lukin, P.; Masuda, M.; Matvienko, D.; Miyabayashi, K.; Miyake, H.; Miyata, H.; Mizuk, R.; Mohanty, S.; Moll, A.; Moon, H. K.; Mori, T.; Mussa, R.; Nakano, E.; Nakao, M.; Nanut, T.; Natkaniec, Z.; Nayak, M.; Niiyama, M.; Nisar, N. K.; Nishida, S.; Ogawa, S.; Okuno, S.; Oswald, C.; Pakhlov, P.; Pakhlova, G.; Pal, B.; Park, C. W.; Park, H.; Pedlar, T. K.; Pestotnik, R.; Petrič, M.; Piilonen, L. E.; Ribežl, E.; Ritter, M.; Rostomyan, A.; Ryu, S.; Sahoo, H.; Sakai, K.; Sakai, Y.; Sandilya, S.; Santelj, L.; Sanuki, T.; Savinov, V.; Schneider, O.; Schnell, G.; Schwanda, C.; Seino, Y.; Senyo, K.; Seon, O.; Sevior, M. E.; Shebalin, V.; Shibata, T. -A.; Shiu, J. -G.; Simon, F.; Sohn, Y. -S.; Sokolov, A.; Solovieva, E.; Starič, M.; Sumihama, M.; Sumisawa, K.; Sumiyoshi, T.; Tamponi, U.; Teramoto, Y.; Trusov, V.; Uchida, M.; Uglov, T.; Unno, Y.; Uno, S.; Usov, Y.; Van Hulse, C.; Vanhoefer, P.; Varner, G.; Vorobyev, V.; Vossen, A.; Wagner, M. N.; Wang, C. H.; Wang, M. -Z.; Wang, P.; Watanabe, M.; Watanabe, Y.; Williams, K. M.; Won, E.; Yamaoka, J.; Yashchenko, S.; Yelton, J.; Yusa, Y.; Zhang, Z. P.; Zhilich, V.; Zhulanov, V.

    2015-11-01

    We report the first double differential cross sections of two charged pions and kaons (e+e- ->hhX) in electron-positron annihilation as a function of the fractional energies of the two hadrons for any charge and hadron combination. The dependence of these di-hadron cross sections on the topology (same, opposite-hemisphere or anywhere) is also studied with the help of the event shape variable combinations directly shed light on the contributing fragmentation functions. For example, we find energies where disfavored fragmentation is expected to be suppressed. These di-hadron results are the KEKB asymmetric-energy e+e- collider. Extending the previously published single-pion and single-kaon cross sections, single-proton (e+e- -> pX) cross sections are extracted from a 159 fb^-1 data sub-sample.

  18. Role of protein surface charge in monellin sweetness.

    Science.gov (United States)

    Xue, Wei-Feng; Szczepankiewicz, Olga; Thulin, Eva; Linse, Sara; Carey, Jannette

    2009-03-01

    A small number of proteins have the unusual property of tasting intensely sweet. Despite many studies aimed at identifying their sweet taste determinants, the molecular basis of protein sweetness is not fully understood. Recent mutational studies of monellin have implicated positively charged residues in sweetness. In the present work, the effect of overall net charge was investigated using the complementary approach of negative charge alterations. Multiple substitutions of Asp/Asn and Glu/Gln residues radically altered the surface charge of single-chain monellin by removing six negative charges or adding four negative charges. Biophysical characterization using circular dichroism, fluorescence, and two-dimensional NMR demonstrates that the native fold of monellin is preserved in the variant proteins under physiological solution conditions although their stability toward chemical denaturation is altered. A human taste test was employed to determine the sweetness detection threshold of the variants. Removal of negative charges preserves monellin sweetness, whereas added negative charge has a large negative impact on sweetness. Meta-analysis of published charge variants of monellin and other sweet proteins reveals a general trend toward increasing sweetness with increasing positive net charge. Structural mapping of monellin variants identifies a hydrophobic surface predicted to face the receptor where introduced positive or negative charge reduces sweetness, and a polar surface where charges modulate long-range electrostatic complementarity.

  19. Charge gradient microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Roelofs, Andreas; Hong, Seungbum

    2018-02-06

    A method for rapid imaging of a material specimen includes positioning a tip to contact the material specimen, and applying a force to a surface of the material specimen via the tip. In addition, the method includes moving the tip across the surface of the material specimen while removing electrical charge therefrom, generating a signal produced by contact between the tip and the surface, and detecting, based on the data, the removed electrical charge induced through the tip during movement of the tip across the surface. The method further includes measuring the detected electrical charge.

  20. Charge equilibrium processes of energetic incident ions and their range

    International Nuclear Information System (INIS)

    Kawagoshi, Hiroshi; Karashima, Shosuke; Watanabe, Tsutomu.

    1984-01-01

    The charge state of energetic ions passing through a certain matter is varied by charge-exchange processes. A rate equation for charge fraction is given by using electron loss and capture cross sections in collision with a target atom under idealized condition. We solved the rate equation of the charge-exchange process of a single electron in a form of linear coupled differential equation. Our calcuiation for the range of ion were carried out for He, Ne and Ar ions passing through an atomic hydrogen gas target. We discuss the charge states of the projectile in relation to a local charge balance consituting a state of charge equilibrium in the target. (author)

  1. Charges for plastic bags : Motivational and behavioral effects

    NARCIS (Netherlands)

    Jakovcevic, Adriana; Steg, Linda; Mazzeo, Nadia; Caballero, Romina; Franco, Paul; Putrino, Natalia; Favara, Jesica

    2014-01-01

    Two field studies tested the effects of a charge for single-use plastic bags recently implemented in Buenos Aires City, Argentina. Study 1 showed a greater increase in consumers' own bag use after the charge was introduced in supermarkets where the policy was introduced, in comparison to control

  2. Analysis of electrostatic powder charging for fractionation of foods

    NARCIS (Netherlands)

    Wang, J.; Wit, de M.; Schutyser, M.A.I.; Boom, R.M.

    2014-01-01

    Electrostatic separation based on different tribo-electric charging behaviours of components has emerged as a novel, sustainable dry fractionation process. This study aims to characterise charging behaviour of single-component particles in nitrogen gas flowing through aluminium tubes. Experiments

  3. Electronic shell structure in multiply charged silver clusters

    International Nuclear Information System (INIS)

    Kandler, O.; Athanassenas, K.; Echt, O.; Kreisle, D.; Leisner, T.; Recknagel, E.

    1991-01-01

    Silver clusters are generated by standard laser vaporization technique and ionized via multiphoton ionization. Time-of-flight mass spectrometry reveals singly, doubly and triply charged clusters, Ag n z+ (z=1, 2, 3). The spectra show, for all charge states, intensity variations, indicating enhanced stabilities for cluster sizes with closed electronic configurations in accord with the spherical jellium model. (orig.)

  4. Cost Monotonic "Cost and Charge" Rules for Connection Situations

    NARCIS (Netherlands)

    Moretti, S.; Tijs, S.H.; Brânzei, R.; Norde, H.W.

    2005-01-01

    The special class of conservative charge systems for minimum cost spanning tree (mcst) situations is introduced.These conservative charge systems lead to single-valued rules for mcst situations, which can also be described with the aid of obligation functions and are, consequently, cost monotonic.A

  5. Radiation by moving charges

    International Nuclear Information System (INIS)

    Geloni, Gianluca; Kocharyan, Vitali; Saldin, Evgeni

    2017-04-01

    It is generally accepted that in order to describe the dynamics of relativistic particles in the laboratory (lab) frame it is sufficient to take into account the relativistic dependence of the particle momenta on the velocity. This solution of the dynamics problem in the lab frame makes no reference to Lorentz transformations. For this reason they are not discussed in particle tracking calculations in accelerator and plasma physics. It is generally believed that the electrodynamics problem can be treated within the same ''single inertial frame'' description without reference to Lorentz transformations. In particular, in order to evaluate radiation fields arising from charged particles in motion we need to know their velocities and positions as a function of the lab frame time t. The relativistic motion of a particle in the lab frame is described by Newton's second law ''corrected'' for the relativistic dependence of momentum on velocity. It is assumed in all standard derivations that one can perform identification of the trajectories in the source part of the usual Maxwell's equations with the trajectories vector x(t) measured (or calculated by using the corrected Newton's second law) in the lab frame. This way of coupling fields and particles is considered since more than a century as the relativistically correct procedure.We argue that this procedure needs to be changed, and we demonstrate the following, completely counterintuitive statement: the results of conventional theory of radiation by relativistically moving charges are not consistent with the principle of relativity. In order to find the trajectory of a particle in the lab frame consistent with the usual Maxwell's equations, one needs to solve the dynamic equation inmanifestly covariant form by using the coordinate-independent proper time τ to parameterize the particle world-line in space-time. We show that there is a difference between &apos

  6. Water Quality Protection Charges

    Data.gov (United States)

    Montgomery County of Maryland — The Water Quality Protection Charge (WQPC) is a line item on your property tax bill. WQPC funds many of the County's clean water initiatives including: • Restoration...

  7. Space-Charge Effect

    CERN Document Server

    Chauvin, N.

    2013-12-16

    First, this chapter introduces the expressions for the electric and magnetic space-charge internal fields and forces induced by high-intensity beams. Then, the root-mean-square equation with space charge is derived and discussed. In the third section, the one-dimensional Child-Langmuir law, which gives the maximum current density that can be extracted from an ion source, is exposed. Space-charge compensation can occur in the low-energy beam transport lines (located after the ion source). This phenomenon, which counteracts the spacecharge defocusing effect, is explained and its main parameters are presented. The fifth section presents an overview of the principal methods to perform beam dynamics numerical simulations. An example of a particles-in-cells code, SolMaxP, which takes into account space-charge compensation, is given. Finally, beam dynamics simulation results obtained with this code in the case of the IFMIF injector are presented.

  8. Electric charge quantization

    International Nuclear Information System (INIS)

    Foot, R.; Lew, H.; Volkas, R.R.

    1992-06-01

    Experimentally it has been known for a long time that the electric charges of the observed particles appear to be quantized. An approach to understanding electric charge quantization that can be used for gauge theories with explicit U(1) factors - such as the standard model and its variants - is pedagogically reviewed and discussed in this article. This approach used the allowed invariances of the Lagrangian and their associated anomaly cancellation equations. It is demonstrated that charge may be de-quantized in the three-generation standard model with massless neutrinos, because differences in family-lepton-numbers are anomaly-free. The relevant experimental limits are also reviewed. This approach to charge quantization suggests that the minimal standard model should be extended so that family-lepton-number differences are explicitly broken. Some candidate extensions such as the minimal standard model augmented by Majorana right-handed neutrinos are also briefly discussed. 30 refs

  9. EV Charging Infrastructure Roadmap

    Energy Technology Data Exchange (ETDEWEB)

    Karner, Donald [Electric Transportation Inc., Rogers, AR (United States); Garetson, Thomas [Electric Transportation Inc., Rogers, AR (United States); Francfort, Jim [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2016-08-01

    As highlighted in the U.S. Department of Energy’s EV Everywhere Grand Challenge, vehicle technology is advancing toward an objective to “… produce plug-in electric vehicles that are as affordable and convenient for the average American family as today’s gasoline-powered vehicles …” [1] by developing more efficient drivetrains, greater battery energy storage per dollar, and lighter-weight vehicle components and construction. With this technology advancement and improved vehicle performance, the objective for charging infrastructure is to promote vehicle adoption and maximize the number of electric miles driven. The EV Everywhere Charging Infrastructure Roadmap (hereafter referred to as Roadmap) looks forward and assumes that the technical challenges and vehicle performance improvements set forth in the EV Everywhere Grand Challenge will be met. The Roadmap identifies and prioritizes deployment of charging infrastructure in support of this charging infrastructure objective for the EV Everywhere Grand Challenge

  10. Visualization of Nicotine Adenine Dinucleotide Redox Homeostasis with Genetically Encoded Fluorescent Sensors.

    Science.gov (United States)

    Zhao, Yuzheng; Zhang, Zhuo; Zou, Yejun; Yang, Yi

    2018-01-20

    Beyond their roles as redox currency in living organisms, pyridine dinucleotides (NAD + /NADH and NADP + /NADPH) are also precursors or cosubstrates of great significance in various physiologic and pathologic processes. Recent Advances: For many years, it was challenging to develop methodologies for monitoring pyridine dinucleotides in situ or in vivo. Recent advances in fluorescent protein-based sensors provide a rapid, sensitive, specific, and real-time readout of pyridine dinucleotide dynamics in single cells or in vivo, thereby opening a new era of pyridine dinucleotide bioimaging. In this article, we summarize the developments in genetically encoded fluorescent sensors for NAD + /NADH and NADP + /NADPH redox states, as well as their applications in life sciences and drug discovery. The strengths and weaknesses of individual sensors are also discussed. These sensors have the advantages of being specific and organelle targetable, enabling real-time monitoring and subcellular-level quantification of targeted molecules in living cells and in vivo. NAD + /NADH and NADP + /NADPH have distinct functions in metabolic and redox regulation, and thus, a comprehensive evaluation of metabolic and redox states must be multiplexed with a combination of various metabolite sensors in a single cell. Antioxid. Redox Signal. 28, 213-229.

  11. Electric Vehicle Charging Modeling

    OpenAIRE

    Grahn, Pia

    2014-01-01

    With an electrified passenger transportation fleet, carbon dioxide emissions could be reduced significantly depending on the electric power production mix. Increased electric power consumption due to electric vehicle charging demands of electric vehicle fleets may be met by increased amount of renewable power production in the electrical systems. With electric vehicle fleets in the transportation system there is a need for establishing an electric vehicle charging infrastructure that distribu...

  12. Recognition and repair of the CC-1065-(N3-Adenine)-DNA adduct by the UVRABC nuclease

    International Nuclear Information System (INIS)

    Tang, M.; Lee, C.S.; Doisy, R.; Ross, L.; Needham-VanDevanter, D.R.; Hurley, L.H.

    1988-01-01

    The recognition and repair of the helix-stabilizing and relatively nondistortive CC-1065-(N3-adenine)-DNA adduct by UVRABC nuclease has been investigated both in vivo with phi X174RFI DNA by a transfection assay and in vitro by a site-directed adduct in a 117 base pair fragment from M13mp1. CC-1065 is a potent antitumor antibiotic produced by Streptomyces zelensis which binds within the minor groove of DNA through N3 of adenine. In contrast to the helix-destabilizing and distortive modifications of DNA caused by ultraviolet light or N-acetoxy-2-(acetylamino)fluorene, CC-1065 increases the melting point of DNA and decreases the S1 nuclease activity. Using a viral DNA-Escherichia coli transfection system, the authors have found that the uvrA, uvrB, and uvrC genes, which code for the major excision repair proteins for UV- and NAAAF-induced DNA damage, are also involved in the repair of CC-1065-DNA adducts. In contrast, the uvrD gene product, which has been found to be involved in the repair of UV damage, has no effect in repairing CC-1065-DNA adducts. Purified UVRA, UVRB, and UVRC proteins must work in concert to incise the drug-modified phi X174RFI DNA. Using a site-directed and multiple CC-1065 modified (MspI-BstNI) 117 base pair fragment from M13mp1, they have found that UVRABC nuclease incises at the eight phosphodiester bond on the 5' side of the CC-1065-DNA adduct on the drug-modified strand. The enzymes do not cut the noncovalently modified strand. The DNA sequence and/or helix-stabilizing effect of multiple adducts may determine the recognition and/or incision of the drug-DNA adduct by UVRABC nuclease. These results are discussed in relation to the structure of the CC-1065-DNA adduct and the effect of drug binding on local DNA structure

  13. Pharmacokinetic and antiretroviral activity in mice of oral [P(1),P(2)-bis[2-(adenin-9-yl)ethoxymethyl]phosphonate], a prodrug of 9-(2-phosphonylmethoxyethyl)adenine.

    Science.gov (United States)

    Rossi, Luigia; Dominici, Sabrina; Serafini, Sonja; Casabianca, Anna; Cerasi, Aurora; Chiarantini, Laura; Celeste, Angela Gabriela; Cappellacci, Loredana; Franchetti, Palmarisa; Grifantini, Mario; Magnani, Mauro

    2002-09-01

    9-(2-Phosphonylmethoxyethyl)adenine (PMEA) is an antiviral drug with activity against herpes viruses, Epstein-Barr virus and retroviruses, including the human immunodeficiency virus. Unfortunately, oral PMEA administration, as required for long-term therapy, is hindered by its low bioavailability. In the present study, the synthesis, oral bioavailability and antiretroviral activity of a new prodrug of PMEA, consisting of two molecules of PMEA bound together by a P-O-P bond (Bis-PMEA), are reported. Pharmacokinetic experiments in mice showed that the oral bioavailabilities of PMEA following oral gavage of Bis-PMEA or PMEA (at a dose equivalent to 28 mg of PMEA/kg) were 50.8 and 13.5%, respectively. These results correlate with the antiviral efficacy of Bis-PMEA administered orally at a dose equivalent to 50 mg/kg of PMEA in C57 BL/6 mice infected with the retroviral complex LP-BM5. Oral treatment with Bis-PMEA proved to be more effective than oral treatment with PMEA given at equimolar doses. Moreover, oral Bis-PMEA was more effective than intraperitoneal PMEA (50 mg/kg) in reducing lymphoadenopathy, hypergammaglobulinaemia and lymph node proviral DNA content, overall in the first weeks post virus inoculation. Bis-PMEA thus appears to be an efficient oral prodrug of PMEA without significant toxicity, at least in this mouse model.

  14. Enabling fast charging – Vehicle considerations

    Energy Technology Data Exchange (ETDEWEB)

    Meintz, Andrew; Zhang, Jiucai; Vijayagopal, Ram; Kreutzer, Cory; Ahmed, Shabbir; Bloom, Ira; Burnham, Andrew; Carlson, Richard B.; Dias, Fernando; Dufek, Eric J.; Francfort, James; Hardy, Keith; Jansen, Andrew N.; Keyser, Matthew; Markel, Anthony; Michelbacher, Christopher; Mohanpurkar, Manish; Pesaran, Ahmad; Scoffield, Don; Shirk, Matthew; Stephens, Thomas; Tanim, Tanvir

    2017-11-01

    To achieve a successful increase in the plug-in battery electric vehicle (BEV) market, it is anticipated that a significant improvement in battery performance is required to improve the range that BEVs can travel and the rate at which they can be recharged. While the range that BEVs can travel on a single recharge is improving, the recharging rate is still much slower than the refueling rate of conventional internal combustion engine vehicles. To achieve comparable recharge times, we explore the vehicle considerations of charge rates of at least 400 kW. Faster recharge is expected to significantly mitigate the perceived deficiencies for long-distance transportation, to provide alternative charging in densely populated areas where overnight charging at home may not be possible, and to reduce range anxiety for travel within a city when unplanned charging may be required. This substantial increase in charging rate is expected to create technical issues in the design of the battery system and vehicle’s electrical architecture that must be resolved. This work focuses on battery system thermal design and total recharge time to meet the goals of implementing higher charge rates and the impacts of the expected increase in system voltage on the components of the vehicle.

  15. Asymptotic analysis of ultra-relativistic charge

    International Nuclear Information System (INIS)

    Burton, D.A.; Gratus, J.; Tucker, R.W.

    2007-01-01

    This article offers a new approach for analysing the dynamic behaviour of distributions of charged particles in an electromagnetic field. After discussing the limitations inherent in the Lorentz-Dirac equation for a single point particle a simple model is proposed for a charged continuum interacting self-consistently with the Maxwell field in vacuo. The model is developed using intrinsic tensor field theory and exploits to the full the symmetry and light-cone structure of Minkowski spacetime. This permits the construction of a regular stress-energy tensor whose vanishing divergence determines a system of non-linear partial differential equations for the velocity and self-fields of accelerated charge. Within this covariant framework a particular perturbation scheme is motivated by an exact class of solutions to this system describing the evolution of a charged fluid under the combined effects of both self and external electromagnetic fields. The scheme yields an asymptotic approximation in terms of inhomogeneous linear equations for the self-consistent Maxwell field, charge current and time-like velocity field of the charged fluid and is defined as an ultra-relativistic configuration. To facilitate comparisons with existing accounts of beam dynamics an appendix translates the tensor formulation of the perturbation scheme into the language involving electric and magnetic fields observed in a laboratory (inertial) frame

  16. Regulation of PutA-membrane associations by flavin adenine dinucleotide reduction.

    Science.gov (United States)

    Zhang, Weimin; Zhou, Yuzhen; Becker, Donald F

    2004-10-19

    Proline utilization A (PutA) from Escherichia coli is a multifunctional flavoprotein that is both a transcriptional repressor of the proline utilization (put) genes and a membrane-associated enzyme which catalyzes the 4-electron oxidation of proline to glutamate. Previously, proline was shown to induce PutA-membrane binding and alter the intracellular location and function of PutA. To distinguish the roles of substrate binding and FAD reduction in the mechanism of how PutA changes from a DNA-binding protein to a membrane-bound enzyme, the kinetic parameters of PutA-membrane binding were measured under different conditions using model lipid bilayers and surface plasmon resonance (SPR). The effects of proline, FAD reduction, and proline analogues on PutA-membrane associations were determined. Oxidized PutA shows no binding to E. coli polar lipid vesicles. In contrast, proline and sodium dithionite induce tight binding of PutA to the lipid bilayer with indistinguishable kinetic parameters and an estimated dissociation constant (K(D)) of PutA-lipid complex. Proline analogues such as L-THFA and DL-P5C also stimulate PutA binding to E. coli polar lipid vesicles with K(D) values ranging from approximately 3.6 to 34 nM (pH 7.4) for the PutA-lipid complex. The greater PutA-membrane binding affinity (>300-fold) generated by FAD reduction relative to the nonreducing ligands demonstrates that FAD reduction controls PutA-membrane associations. On the basis of SPR kinetic analysis with differently charged lipid bilayers, the driving force for PutA-membrane binding is primarily hydrophobic. In the SPR experiments membrane-bound PutA did not bind put control DNA, confirming that the membrane-binding and DNA-binding activities of PutA are mutually exclusive. A model for the regulation of PutA is described in which the overall translocation of PutA from the cytoplasm to the membrane is driven by FAD reduction and the subsequent energy difference ( approximately 24 kJ/mol) between

  17. Time resolved ion beam induced charge collection

    International Nuclear Information System (INIS)

    Sexton W, Frederick; Walsh S, David; Doyle L, Barney; Dodd E, Paul

    2000-01-01

    Under this effort, a new method for studying the single event upset (SEU) in microelectronics has been developed and demonstrated. Called TRIBICC, for Time Resolved Ion Beam Induced Charge Collection, this technique measures the transient charge-collection waveform from a single heavy-ion strike with a -.03db bandwidth of 5 GHz. Bandwidth can be expanded up to 15 GHz (with 5 ps sampling windows) by using an FFT-based off-line waveform renormalization technique developed at Sandia. The theoretical time resolution of the digitized waveform is 24 ps with data re-normalization and 70 ps without re-normalization. To preserve the high bandwidth from IC to the digitizing oscilloscope, individual test structures are assembled in custom high-frequency fixtures. A leading-edge digitized waveform is stored with the corresponding ion beam position at each point in a two-dimensional raster scan. The resulting data cube contains a spatial charge distribution map of up to 4,096 traces of charge (Q) collected as a function of time. These two dimensional traces of Q(t) can cover a period as short as 5 ns with up to 1,024 points per trace. This tool overcomes limitations observed in previous multi-shot techniques due to the displacement damage effects of multiple ion strikes that changed the signal of interest during its measurement. This system is the first demonstration of a single-ion transient measurement capability coupled with spatial mapping of fast transients

  18. Magnetotransport and charge transfer studies on delta-modulation-doped In sub x Ga sub 1 sub - sub x As/Al sub y Ga sub 1 sub - sub y As strained single quantum wells

    CERN Document Server

    Jung, M; Kim, T W; Yoo, K H; Kim, M D; Park, H S; Kim, D L

    1999-01-01

    Shubnikov-de Haas (S-dH) and Van der Pauw Hall-effect measurements on a In sub 0 sub . sub 1 sub 8 Ga sub 0 sub . sub 8 sub 2 As/Al sub 0 sub . sub 2 sub 5 Ga sub 0 sub . sub 7 sub 5 As strained single quantum well grown by molecular beam epitaxy have been performed to investigate the existence of the two-dimensional electron gas (2DEG) in the In sub 0 sub . sub 1 sub 8 Ga sub 0 sub . sub 8 sub 2 As single quantum well. The fast Fourier transform for the S-dH data and the observation of the quantum Hall effect clearly indicate 2DEG occupation of a subband in the In sub 0 sub . sub 1 sub 8 Ga sub 0 sub . sub 8 sub 2 As single quantum well. Electronic subband energy and the corresponding wavefunction in the In sub 0 sub . sub 1 sub 8 Ga sub 0 sub . sub 8 sub 2 As quantum well were calculated by a self-consistent method taking into account exchange-correlation effects together with strain and nonparabolicity effects.

  19. Charge transport by holographic Fermi surfaces

    CERN Document Server

    Faulkner, Thomas; Liu, Hong; McGreevy, John; Vegh, David

    2013-01-01

    We compute the contribution to the conductivity from holographic Fermi surfaces obtained from probe fermions in an AdS charged black hole. This requires calculating a certain part of the one-loop correction to a vector propagator on the charged black hole geometry. We find that the current dissipation is as efficient as possible and the transport lifetime coincides with the single-particle lifetime. In particular, in the case where the spectral density is that of a marginal Fermi liquid, the resistivity is linear in temperature.

  20. New Method for Double-Resonance Spectroscopy in a Cold Quadrupole Ion Trap and Its Application to UV-UV Hole-Burning Spectroscopy of Protonated Adenine Dimer.

    Science.gov (United States)

    Kang, Hyuk; Féraud, Géraldine; Dedonder-Lardeux, Claude; Jouvet, Christophe

    2014-08-07

    A novel method for double-resonance spectroscopy in a cold quadrupole ion trap is presented, which utilizes dipolar resonant excitation of fragment ions in the quadrupole ion trap. Photofragments by a burn laser are removed by applying an auxiliary RF to the trap, and a probe laser detects the depletion of photofragments by the burn laser. By scanning the wavelength of the burn laser, conformation-specific UV spectrum of a cold ion is obtained. This simple and powerful method is applicable to any type of double-resonance spectroscopy in a cold quadrupole ion trap and was applied to UV-UV hole-burning spectroscopy of protonated adenine dimer. It was found that protonated adenine dimer has multiple conformers/tautomers, each with multiple excited states with drastically different excited state dynamics.

  1. Effect of UV-irradiation in vitro on adenin nucleotides metabolism, Na+ and K+ concentration, osmotic properties and submicroscopic structure of pigeon red blood cells

    International Nuclear Information System (INIS)

    Kabat, I.A.; Sysa, J.; Leyko, W.; Kwiatkowski, B.; Sysa, A.; Zakrzewska, I.; Hlynczak, A.; Lodz Univ.; Akademia Medyczna, Lodz; Akademia Medyczna, Gdansk

    1975-01-01

    Effect of UV-irradiation in vitro on metabolism of adenine nucleotides: ADP, ATP and AXP, osmotic properties and submicroscopic structure of nucleated pigeon red blood cell was investigated. Irradiation was carried out for 60, 120, 180, 240 and 300 minutes. Hanau S-500 lamp with efficiency 4.34 x 10 8 erg/sec was used. A decrease of ATP content with a simultaneous increase of ADP and AXP contents and a rather constant level of the sum of adenine compounds was observed. UV-irradiation caused a decrease of reversal of hemolysis and osmotic resistance to hypotonic NaCl solutions. An equivalent exchange of Na + and K + ions and an increase of hematocrit value, following UV-irradiation was observed. Electron microscope studies demonstrated changes of ultrastructure concerning both cell nucleus and thickness and granulation of cell membrane. (orig.) [de

  2. Electron-transfer studies with a new flavin adenine dinucleotide dependent glucose dehydrogenase and osmium polymers of different redox potentials.

    Science.gov (United States)

    Zafar, Muhammad Nadeem; Wang, Xiaoju; Sygmund, Christoph; Ludwig, Roland; Leech, Dónal; Gorton, Lo

    2012-01-03

    A new extracellular flavin adenine dinucleotide (FAD)-dependent glucose dehydrogenase from Glomerella cingulata (GcGDH) was electrochemically studied as a recognition element in glucose biosensors. The redox enzyme was recombinantly produced in Pichia pastoris and homogeneously purified, and its glucose-oxidizing properties on spectrographic graphite electrodes were investigated. Six different Os polymers, the redox potentials of which ranged in a broad potential window between +15 and +489 mV versus the normal hydrogen electrode (NHE), were used to immobilize and "wire" GcGDH to the spectrographic graphite electrode's surface. The GcGDH/Os polymer modified electrodes were evaluated by chronoamperometry using flow injection analysis. The current response was investigated using a stepwisely increased applied potential. It was observed that the ratio of GcGDH/Os polymer and the overall loading of the enzyme electrode significantly affect the performance of the enzyme electrode for glucose oxidation. The best-suited Os polymer [Os(4,4'-dimethyl-2,2'-bipyridine)(2)(PVI)Cl](+) had a potential of +309 mV versus NHE, and the optimum GcGDH/Os polymer ratio was 1:2 yielding a maximum current density of 493 μA·cm(-2) at a 30 mM glucose concentration. © 2011 American Chemical Society

  3. Purification and characterization of the enzymes involved in nicotinamide adenine dinucleotide degradation by Penicillium brevicompactum NRC 829.

    Science.gov (United States)

    Ali, Thanaa Hamed; El-Ghonemy, Dina Helmy

    2016-06-01

    The present study was conducted to investigate a new pathway for the degradation of nicotinamide adenine dinucleotide (NAD) by Penicillium brevicompactum NRC 829 extracts. Enzymes involved in the hydrolysis of NAD, i.e. alkaline phosphatase, aminohydrolase and glycohydrolase were determined. Alkaline phosphatase was found to catalyse the sequential hydrolysis of two phosphate moieties of NAD molecule to nicotinamide riboside plus adenosine. Adenosine was then deaminated by aminohydrolase to inosine and ammonia. While glycohydrolase catalyzed the hydrolysis of the nicotinamide-ribosidic bond of NAD+ to produce nicotinamide and ADP-ribose in equimolar amounts, enzyme purification through a 3-step purification procedure revealed the existence of two peaks of alkaline phosphatases, and one peak contained deaminase and glycohydrolase activities. NAD deaminase was purified to homogeneity as estimated by sodium dodecyl sulphate-polyacrylamide gel electrophoresis with an apparent molecular mass of 91 kDa. Characterization and determination of some of NAD aminohydrolase kinetic properties were conducted due to its biological role in the regulation of cellular NAD level. The results also revealed that NAD did not exert its feedback control on nicotinamide amidase produced by P. brevicompactum.

  4. Genetic mapping of human heart-skeletal muscle adenine nucleotide translocator and its relationship to the facioscapulohumeral muscular dystrophy locus

    Energy Technology Data Exchange (ETDEWEB)

    Haraguchi, Y.; Chung, A.B.; Torroni, A.; Stepien, G.; Shoffner, J.M.; Costigan, D.A.; Polak, M. [Emory Univ. School of Medicine, Atlanta, GA (United States); Wasmuth, J.J.; Altherr, M.R.; Winokur, S.T. [Univ. of California, Irvine, CA (United States)] [and others

    1993-05-01

    The mitochondrial heart-skeletal muscle adenine nucleotide translocator (ANT1) was regionally mapped to 4q35-qter using somatic cell hybrids containing deleted chromosome 4. The regional location was further refined through family studies using ANT1 intron and promoter nucleotide polymorphisms recognized by the restriction endonucleases MboII, NdeI, and HaeIII. Two alleles were found, each at a frequency of 0.5. The ANT1 locus was found to be closely linked to D4S139, D4S171, and the dominant skeletal muscle disease locus facioscapulohumeral muscular dystrophy (FSHD). A crossover that separated D4S171 and ANT1 from D4S139 was found. Since previous studies have established the chromosome 4 map order as centromere-D4S171-D4S139-FSHD, it was concluded that ANT1 is located on the side of D4S139, that is opposite from FSHD. This conclusion was confirmed by sequencing the exons and analyzing the transcripts of ANT1 from several FSHD patients and finding no evidence of aberration. 35 refs., 5 figs., 1 tab.

  5. Photosensitized oxidation of nicotinamide adenine dinucleotide by diethoxyphosphorus(V)tetraphenylporphyrin and its fluorinated derivative: Possibility of chain reaction

    Science.gov (United States)

    Hirakawa, Kazutaka; Murata, Atsushi

    2018-01-01

    Water-soluble porphyrins, diethoxyphosphorus(V)tetraphenylporphyrin (EtP(V)TPP) and its fluorinated analogue (FEtP(V)TPP), decreased the typical absorption around 340 nm of nicotinamide adenine dinucleotide (NADH) under visible light irradiation, indicating oxidative decomposition. A singlet oxygen quencher, sodium azide, and a triplet quencher, potassium iodide, slightly inhibited photosensitized NADH oxidation. However, these inhibitory effects were very small. Furthermore, the fluorescence lifetime of these P(V)porphyrins was decreased by NADH, suggesting the contribution of electron transfer to the singlet excited (S1) state of P(V)porphyrin. The redox potential measurement supports the electron transfer-mediated oxidation of NADH. The quantum yields of NADH photodecomposition by P(V)porphyrins could be estimated from the kinetic data and the effect of these quenchers on NADH oxidation. The obtained values suggest that the electron accepting by the S1 states of P(V)porphyrins triggers a chain reaction of NADH oxidation. This photosensitized reaction may play an important role in the photocytotoxicity of P(V)porphyrins. The axial ligand fluorination of P(V)porphyrins improved electron accepting ability. However, fluorination slightly suppressed static interaction with NADH, resulting in decreased oxidation quantum yield.

  6. Mitochondrial nicotinamide adenine dinucleotide reduced (NADH) oxidation links the tricarboxylic acid (TCA) cycle with methionine metabolism and nuclear DNA methylation.

    Science.gov (United States)

    Lozoya, Oswaldo A; Martinez-Reyes, Inmaculada; Wang, Tianyuan; Grenet, Dagoberto; Bushel, Pierre; Li, Jianying; Chandel, Navdeep; Woychik, Richard P; Santos, Janine H

    2018-04-18

    Mitochondrial function affects many aspects of cellular physiology, and, most recently, its role in epigenetics has been reported. Mechanistically, how mitochondrial function alters DNA methylation patterns in the nucleus remains ill defined. Using a cell culture model of induced mitochondrial DNA (mtDNA) depletion, in this study we show that progressive mitochondrial dysfunction leads to an early transcriptional and metabolic program centered on the metabolism of various amino acids, including those involved in the methionine cycle. We find that this program also increases DNA methylation, which occurs primarily in the genes that are differentially expressed. Maintenance of mitochondrial nicotinamide adenine dinucleotide reduced (NADH) oxidation in the context of mtDNA loss rescues methionine salvage and polyamine synthesis and prevents changes in DNA methylation and gene expression but does not affect serine/folate metabolism or transsulfuration. This work provides a novel mechanistic link between mitochondrial function and epigenetic regulation of gene expression that involves polyamine and methionine metabolism responding to changes in the tricarboxylic acid (TCA) cycle. Given the implications of these findings, future studies across different physiological contexts and in vivo are warranted.

  7. Regulation of the Salmonella enterica std fimbrial operon by DNA adenine methylation, SeqA, and HdfR.

    Science.gov (United States)

    Jakomin, Marcello; Chessa, Daniela; Bäumler, Andreas J; Casadesús, Josep

    2008-11-01

    DNA adenine methylase (dam) mutants of Salmonella enterica serovar Typhimurium grown under laboratory conditions express the std fimbrial operon, which is tightly repressed in the wild type. Here, we show that uncontrolled production of Std fimbriae in S. enterica serovar Typhimurium dam mutants contributes to attenuation in mice, as indicated by the observation that an stdA dam strain is more competitive than a dam strain upon oral infection. Dam methylation appears to regulate std transcription, rather than std mRNA stability or turnover. A genetic screen for std regulators showed that the GATC-binding protein SeqA directly or indirectly represses std expression, while the poorly characterized yifA gene product serves as an std activator. YifA encodes a putative LysR-like protein and has been renamed HdfR, like its Escherichia coli homolog. Activation of std expression by HdfR is observed only in dam and seqA backgrounds. These data suggest that HdfR directly or indirectly activates std transcription. Since SeqA is unable to bind nonmethylated DNA, it is possible that std operon derepression in dam and seqA mutants may result from unconstrained HdfR-mediated activation of std transcription. Derepression of std in dam and seqA mutants of S. enterica occurs in only a fraction of the bacterial population, suggesting the occurrence of either bistable expression or phase variation.

  8. The tumour metabolism inhibitors GSAO and PENAO react with cysteines 57 and 257 of mitochondrial adenine nucleotide translocase

    Directory of Open Access Journals (Sweden)

    Park Danielle

    2012-03-01

    Full Text Available Abstract Background GSAO (4-(N-(S-glutathionylacetylamino phenylarsonous acid and PENAO (4-(N-(S-penicillaminylacetylamino phenylarsonous acid are tumour metabolism inhibitors that target adenine nucleotide translocase (ANT of the inner-mitochondrial membrane. Both compounds are currently being trialled in patients with solid tumours. The trivalent arsenical moiety of GSAO and PENAO reacts with two matrix facing cysteine residues of ANT, inactivating the transporter. This leads to proliferation arrest and death of tumour and tumour-supporting cells. Results The two reactive ANT cysteine residues have been identified in this study by expressing cysteine mutants of human ANT1 in Saccharomyces cerevisiae and measuring interaction with the arsenical moiety of GSAO and PENAO. The arsenic atom of both compounds cross-links cysteine residues 57 and 257 of human ANT1. Conclusions The sulphur atoms of these two cysteines are 20 Å apart in the crystal structures of ANT and the optimal spacing of cysteine thiolates for reaction with As (III is 3-4 Å. This implies that a significant conformational change in ANT is required for the organoarsenicals to react with cysteines 57 and 257. This conformational change may relate to the selectivity of the compounds for proliferating cells.

  9. Synthesis, conformational analysis, and biological activity of new analogues of thiazole-4-carboxamide adenine dinucleotide (TAD) as IMP dehydrogenase inhibitors.

    Science.gov (United States)

    Franchetti, Palmarisa; Cappellacci, Loredana; Pasqualini, Michela; Petrelli, Riccardo; Jayaprakasan, Vetrichelvan; Jayaram, Hiremagalur N; Boyd, Donald B; Jain, Manojkumar D; Grifantini, Mario

    2005-03-15

    Thiazole-4-carboxamide adenine dinucleotide (TAD) analogues T-2'-MeAD (1) and T-3'-MeAD (2) containing, respectively, a methyl group at the ribose 2'-C-, and 3'-C-position of the adenosine moiety, were prepared as potential selective human inosine monophosphate dehydrogenase (IMPDH) type II inhibitors. The synthesis of heterodinucleotides was carried out by CDI-catalyzed coupling reaction of unprotected 2'-C-methyl- or 3'-C-methyl-adenosine 5'-monophosphate with 2',3'-O-isopropylidene-tiazofurin 5'-monophosphate, and then deisopropylidenation. Biological evaluation of dinucleotides 1 and 2 as inhibitors of recombinant human IMPDH type I and type II resulted in a good activity. Inhibition of both isoenzymes by T-2'-MeAD and T-3'-MeAD was noncompetitive with respect to NAD substrate. Binding of T-3'-MeAD was comparable to that of parent compound TAD, while T-2'-MeAD proved to be a weaker inhibitor. However, no significant difference was found in inhibition of the IMPDH isoenzymes. T-2'-MeAD and T-3'-MeAD were found to inhibit the growth of K562 cells (IC(50) 30.7 and 65.0muM, respectively).

  10. Blue light induced reactive oxygen species from flavin mononucleotide and flavin adenine dinucleotide on lethality of HeLa cells.

    Science.gov (United States)

    Yang, Ming-Yeh; Chang, Chih-Jui; Chen, Liang-Yü

    2017-08-01

    Photodynamic therapy (PDT) is a safe and non-invasive treatment for cancers and microbial infections. Various photosensitizers and light sources have been developed for clinical cancer therapies. Flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD) are the cofactor of enzymes and are used as photosensitizers in this study. Targeting hypoxia and light-triggering reactive oxygen species (ROS) are experimental strategies for poisoning tumor cells in vitro. HeLa cells are committed to apoptosis when treated with FMN or FAD and exposed to visible blue light (the maximum emitted wavelength of blue light is 462nm). Under blue light irradiation at 3.744J/cm 2 (=0.52mW/cm 2 irradiated for 2h), the minimal lethal dose is 3.125μM and the median lethal doses (LD 50 ) for FMN and FAD are 6.5μM and 7.2μM, respectively. Individual exposure to visible blue light irradiation or riboflavin photosensitizers does not produce cytotoxicity and no side effects are observed in this study. The western blotting results also show that an intrinsic apoptosis pathway is activated by the ROS during photolysis of riboflavin analogues. Blue light triggers the cytotoxicity of riboflavins on HeLa cells in vitro. Based on these results, this is a feasible and efficient of PDT with an intrinsic photosensitizer for cancer research. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Deficiency of the iron-sulfur clusters of mitochondrial reduced nicotinamide-adenine dinucleotide-ubiquinone oxidoreductase (complex I) in an infant with congenital lactic acidosis.

    OpenAIRE

    Moreadith, R W; Batshaw, M L; Ohnishi, T; Kerr, D; Knox, B; Jackson, D; Hruban, R; Olson, J; Reynafarje, B; Lehninger, A L

    1984-01-01

    We report the case of an infant with hypoglycemia, progressive lactic acidosis, an increased serum lactate/pyruvate ratio, and elevated plasma alanine, who had a moderate to profound decrease in the ability of mitochondria from four organs to oxidize pyruvate, malate plus glutamate, citrate, and other NAD+-linked respiratory substrates. The capacity to oxidize the flavin adenine dinucleotide-linked substrate, succinate, was normal. The most pronounced deficiency was in skeletal muscle, the le...

  12. Grafted Azure A modified electrodes as disposable β-nicotinamide adenine dinucleotide sensors.

    Science.gov (United States)

    Revenga-Parra, M; Gómez-Anquela, C; García-Mendiola, T; Gonzalez, E; Pariente, F; Lorenzo, E

    2012-10-17

    We report the in situ generation of aryl diazonium cations of Azure A, a redox-active phenothiazine dye, by reaction between the corresponding aromatic aminophenyl group and sodium nitrite in 0.1 M HCl. The subsequent electrochemical reduction of these dye diazonium salts gives rise to conductive electrografted films onto screen-printed carbon (SPC) electrodes. The resulting Azure A films have a very stable and reversible electrochemical response and exhibit potent and persistent electrocatalytic behavior toward NADH oxidation. We have optimized the electrografting conditions in order to obtain SPC modified electrodes with high and stable electrocatalytic response. The kinetic of the reaction between the NADH and the redox active centers in the Azure A film has been characterized using cyclic voltammetry and single step chronoamperometry. The catalytic currents were proportional to the concentration of NADH giving rise to linear calibration plots up to a concentration of 0.5 mM with a detection limit of 0.57±0.03 μM and a sensitivity of 9.48 A mol cm(-2) μM(-1). The precision of chronoamperometric determinations was found to be 2.3% for five replicate determinations of 3.95 μM NADH. The great stability of such modified electrodes makes them ideal for their application in the development of biosensing platforms based on dehydrogenases. Copyright © 2012 Elsevier B.V. All rights reserved.

  13. A New Manganese Dinuclear Complex with Phenolate Ligands and a Single Unsupported Oxo Bridge. Storage of Two Positive Charges within Less than 500 mV. Relevance to Photosynthesis.

    Science.gov (United States)

    Horner, Olivier; Anxolabéhère-Mallart, Elodie; Charlot, Marie-France; Tchertanov, Lyuba; Guilhem, Jean; Mattioli, Tony A.; Boussac, Alain; Girerd, Jean-Jacques

    1999-03-22

    The compound [Mn(III)(2)OL(2)](ClO(4))(2).2.23CHCl(3).0.65CH(2)Cl(2) where L(-) is the monoanionic N,N-bis(2-pyridylmethyl)-N'-salicyliden-1,2-diaminoethane ligand, has been synthesized. The complex dication [Mn(III)(2)OL(2)](2+) contains a linear Mn(III)-O-Mn(III) unit with a Mn-Mn distance of 3.516 Å. The pentadentate ligand L(-) wraps around the Mn(III) ion. Electrochemically, it is possible to prepare the one electron oxidized trication [Mn(2)OL(2)](3+) which crystallizes as [Mn(2)OL(2)](ClO(4))(2.37)(PF(6))(0.63).1.5CH(3)CN. The complex trication [Mn(2)OL(2)](3+) contains a Mn(III)-O-Mn(IV) unit with a Mn-Mn distance of 3.524 Å and a Mn-O-Mn angle of 178.7(2) degrees. The contraction of the coordination sphere around the Mn(IV) is clearly observed. The [Mn(2)OL(2)](2+) dication possesses a S = 0 electronic ground state with J = -216 cm(-)(1) (H = -JS(1)().S(2)()), whereas the [Mn(2)OL(2)](3+) trication shows a S = (1)/(2) ground state with J = -353 cm(-)(1). The UV-visible spectrum of [Mn(2)OL(2)](3+) exhibits an intense absorption band (epsilon = 3040 M(-)(1) cm(-)(1)) centered at 570 nm assigned to a phenolate --> Mn(IV) charge-transfer transition. The potentials of the redox couples determined by cyclic voltammetry are E degrees ([Mn(2)OL(2)](3+)/[Mn(2)OL(2)](2+)) = 0.54 V/saturated calomel electrode (SCE) and E degrees ([Mn(2)OL(2)](4+)/[Mn(2)OL(2)](3+)) = 0.99 V/SCE. Upon oxidation at 1.3 V/SCE, the band at 570 nm shifts to 710 nm (epsilon = 2500 M(-)(1) cm(-)(1)) and a well-defined band appears at 400 nm which suggests the formation of a phenoxyl radical. The [Mn(2)OL(2)](3+)( )()complex exhibits a 18-line X-band electron paramagnetic resonance (EPR) spectrum which has been simulated with rhombic tensors |A(1)(x)()| = 160 x 10(-)(4) cm(-)(1); |A(1)(y)()| = 130 x 10(-)(4) cm(-)(1); |A(1)(z)()| = 91 x 10(-)(4) cm(-)(1); |A(2)(x)()| = 62 x 10(-)(4) cm(-)(1); |A(2)(y)()| = 59 x 10(-)(4) cm(-)(1); |A(2)(z)()| = 62 x 10(-)(4) cm(-)(1) and g(x)() = 2.006; g

  14. High-NaCl Diet Aggravates Cardiac Injury in Rats with Adenine-Induced Chronic Renal Failure and Increases Serum Troponin T Levels

    DEFF Research Database (Denmark)

    Kashioulis, Pavlos; Hammarsten, Ola; Marcussen, Niels

    2016-01-01

    correlation between the degree of LV fibrosis and serum cTnT levels in ACRF rats (r = 0.81, p diet in rats with ACRF produces LV injury and aggravates increases in serum cTnT levels, presumably by causing hypertension-induced small artery lesions leading......AIMS: To examine the effects of 2 weeks of high-NaCl diet on left ventricular (LV) morphology and serum levels of cardiac troponin T (cTnT) in rats with adenine-induced chronic renal failure (ACRF). METHODS: Male Sprague-Dawley rats either received chow containing adenine or were pair......-fed an identical diet without adenine [controls (C)]. Approximately 10 weeks after the beginning of the study, the rats were randomized to either remain on a normal NaCl diet (NNa; 0.6%) or to be switched to high-NaCl chow (HNa; 4%) for 2 weeks, after which acute experiments were performed. RESULTS: Rats with ACRF...

  15. Binding of p-mercaptobenzoic acid and adenine to gold-coated electroless etched silicon nanowires studied by surface-enhanced Raman scattering.

    Science.gov (United States)

    Mohaček-Grošev, Vlasta; Gebavi, Hrvoje; Bonifacio, Alois; Sergo, Valter; Daković, Marko; Bajuk-Bogdanović, Danica

    2018-04-10

    Modern diagnostic tools ever aim to reduce the amount of analyte and the time needed for obtaining the result. Surface-enhanced Raman spectroscopy is a method that could satisfy both of these requirements, provided that for each analyte an adequate substrate is found. Here we demonstrate the ability of gold-sputtered silicon nanowires (SiNW) to bind p-mercaptobenzoic acid in 10 -3 , 10 -4 and 10 -5 M and adenine in 30 and 100μM concentrations. Based on the normal mode analysis, presented here for the first time, the binding of p-mercaptobenzoic acid is deduced. The intensity enhancement of the 1106cm -1 band is explained by involvement of the CS stretching deformation, and the appearance of the broad 300cm -1 band attributed to SAu stretching mode. Adenine SERS spectra demonstrate the existence of the 7H tautomer since the strongest band observed is at 736cm -1 . The adenine binding is likely to occur in several ways, because the number of observed bands in the 1200-1600cm -1 interval exceeds the number of observed bands in the normal Raman spectrum of the free molecule. Copyright © 2018 Elsevier B.V. All rights reserved.

  16. Crystallization and preliminary X-ray diffraction study of recombinant adenine phosphoribosyltransferase from the thermophilic bacterium Thermus thermophilus strain HB27

    Science.gov (United States)

    Sinitsyna, E. V.; Timofeev, V. I.; Tuzova, E. S.; Kostromina, M. A.; Murav'eva, T. I.; Esipov, R. S.; Kuranova, I. P.

    2017-07-01

    Adenine phosphoribosyltransferase (APRT) belongs to the type I phosphoribosyltransferase family and catalyzes the formation of adenosine monophosphate via transfer of the 5-phosphoribosyl group from phosphoribosyl pyrophosphate to the nitrogen atom N9 of the adenine base. Proteins of this family are involved in a salvage pathway of nucleotide synthesis, thus providing purine base utilization and maintaining the optimal level of purine bases in the body. Adenine phosphoribosyltransferase from the extremely thermophilic Thermus thermophilus strain HB27 was produced using a highly efficient E. coli producer strain and was then purified by affinity and gel-filtration chromatography. This enzyme was successfully employed as a catalyst for the cascade biosynthesis of biologically important nucleotides. The screening of crystallization conditions for recombinant APRT from T. thermophilus HB27 was performed in order to determine the enzyme structure by X-ray diffraction. The crystallization conditions, which were found by the vapor-diffusion technique, were then optimized to apply the counter-diffusion technique. The crystals of the enzyme were grown by the capillary counter-diffusion method. The crystals belong to sp. gr. P1211 and have the following unitcell parameters: a = 69.86 Å, b = 82.16 Å, c = 91.39 Å, α = γ = 90°, β = 102.58°. The X-ray diffraction data set suitable for the determination of the APRT structure at 2.6 Å resolution was collected from the crystals at the SPring-8 synchrotron facility (Japan).

  17. Possible links between glucose-induced changes in the energy state of pancreatic B cells and insulin release. Unmasking by decreasing a stable pool of adenine nucleotides in mouse islets.

    OpenAIRE

    Detimary, P; Jonas, J C; Henquin, J C

    1995-01-01

    Whether adenine nucleotides in pancreatic B cells serve as second messengers during glucose stimulation of insulin secretion remains disputed. Our hypothesis was that the actual changes in ATP and ADP are obscured by the large pool of adenine nucleotides (ATP/ADP ratio close to 1) in insulin granules. Therefore, mouse islets were degranulated acutely with a cocktail of glucose, KCl, forskolin, and phorbol ester or during overnight culture in RPMI-1640 medium containing 10 mM glucose. When the...

  18. Study of the interaction of multiply charged ions and complex systems of biological interest: effects of the molecular environment

    International Nuclear Information System (INIS)

    Capron, Michael

    2011-01-01

    This PhD thesis describes the experimental study of the interaction between slow multiply charged ions (tens of keV) and molecular systems of biological interest (amino acids and nucleobases). It is the aim to identify and to better understand the effect of a molecular environment on different collision induced phenomena. To do so, the time of flight spectra of cationic products emerging from collisions with isolated molecules as well as clusters are compared. It is shown that the molecular environment protects the molecule as it allows to distribute the transferred energies and charges over the whole system (global decrease of the fragmentation and quenching of some fragmentation channels). Furthermore, in the case of adenine clusters, the molecular environment weakens some intramolecular bonds. Moreover, products of chemical reactions are observed concerning proton transfer processes in hydrated cluster of adenine and the formation of peptides bonds between beta-alanine molecules in a cluster. The latter finding is studied as a function of the cluster size and type of the projectile. Some criteria for peptide bond formation, such as flexibility and geometry of the molecule, are investigated for different amino acids. (author)

  19. Charge transfer in astrophysical nebulae

    International Nuclear Information System (INIS)

    Shields, G.A.

    1990-01-01

    Charge transfer has become a standard ingredient in models of ionized nebulae, supernovae remnants and active galactic nuclei. Charge transfer rate coefficients and the physics of ionized nebulae are considered. Charge transfer is applied to the ionization structure and line emission of ionized nebulae. Photoionized nebulae observations are used to test theoretical predictions of charge transfer rates. (author)

  20. Electric vehicle battery charging controller

    DEFF Research Database (Denmark)

    2016-01-01

    to a battery management system in the electric vehicle to charge a battery therein, a first communication unit for receiving a charging message via a communication network, and a control unit for controlling a charging current provided from the charge source to the electric vehicle, the controlling at least...

  1. Dispersion and space charge

    International Nuclear Information System (INIS)

    Venturini, M.; Kishek, R.A.; Reiser, M.

    1998-01-01

    The presence of space charge affects the value of the dispersion function. On the other hand dispersion has a role in shaping the beam distribution and therefore in determining the resulting forces due to space charge. In this paper we present a framework where the interplay between space charge and dispersion for a continuous beam can be simultaneously treated. We revise the derivation of a new set of rms envelope-dispersion equations we have recently proposed in [1]. The new equations generalize the standard rms envelope equations currently used for matching to the case where bends and a longitudinal momentum spread are present. We report a comparison between the solutions of the rms envelope-dispersion equations and the results obtained using WARP, a Particle in Cell (PIC) code, in the modeling of the Maryland Electron Ring. copyright 1998 American Institute of Physics

  2. Dispersion and space charge

    Energy Technology Data Exchange (ETDEWEB)

    Venturini, M. [Department of Physics and Institute for Plasma Research, University of Maryland, College Park, Maryland 20742 (United States); Kishek, R.A.; Reiser, M. [Department of Electrical Engeneering and Institute for Plasma Research, University of Maryland, College Park, Maryland 20742 (United States)

    1998-11-01

    The presence of space charge affects the value of the dispersion function. On the other hand dispersion has a role in shaping the beam distribution and therefore in determining the resulting forces due to space charge. In this paper we present a framework where the interplay between space charge and dispersion for a continuous beam can be simultaneously treated. We revise the derivation of a new set of rms envelope-dispersion equations we have recently proposed in [1]. The new equations generalize the standard rms envelope equations currently used for matching to the case where bends and a longitudinal momentum spread are present. We report a comparison between the solutions of the rms envelope-dispersion equations and the results obtained using WARP, a Particle in Cell (PIC) code, in the modeling of the Maryland Electron Ring. {copyright} {ital 1998 American Institute of Physics.}

  3. Dispersion and space charge

    International Nuclear Information System (INIS)

    Venturini, Marco; Kishek, Rami A.; Reiser, Martin

    1998-01-01

    The presence of space charge affects the value of the dispersion function. On the other hand dispersion has a role in shaping the beam distribution and therefore in determining the resulting forces due to space charge. In this paper we present a framework where the interplay between space charge and dispersion for a continuous beam can be simultaneously treated. We revise the derivation of a new set of rms envelope-dispersion equations we have recently proposed. The new equations generalize the standard rms envelope equations currently used for matching to the case where bends and a longitudinal momentum spread are present. We report a comparison between the solutions of the rms envelope-dispersion equations and the results obtained using WARP, a Particle in Cell (PIC) code, in the modeling of the Maryland Electron Ring

  4. Charged black holes with scalar hair

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Zhong-Ying; Lü, H. [Center for Advanced Quantum Studies, Department of Physics,Beijing Normal University, Beijing 100875 (China)

    2015-09-10

    We consider a class of Einstein-Maxwell-Dilaton theories, in which the dilaton coupling to the Maxwell field is not the usual single exponential function, but one with a stationary point. The theories admit two charged black holes: one is the Reissner-Nordstrøm (RN) black hole and the other has a varying dilaton. For a given charge, the new black hole in the extremal limit has the same AdS{sub 2}×Sphere near-horizon geometry as the RN black hole, but it carries larger mass. We then introduce some scalar potentials and obtain exact charged AdS black holes. We also generalize the results to black p-branes with scalar hair.

  5. Sources for charged particles

    International Nuclear Information System (INIS)

    Arianer, J.

    1997-01-01

    This document is a basic course on charged particle sources for post-graduate students and thematic schools on large facilities and accelerator physics. A simple but precise description of the creation and the emission of charged particles is presented. This course relies on every year upgraded reference documents. Following relevant topics are considered: electronic emission processes, technological and practical considerations on electron guns, positron sources, production of neutral atoms, ionization, plasma and discharge, different types of positive and negative ion sources, polarized particle sources, materials for the construction of ion sources, low energy beam production and transport. (N.T.)

  6. Charged conformal Killing spinors

    Energy Technology Data Exchange (ETDEWEB)

    Lischewski, Andree, E-mail: lischews@mathematik.hu-berlin.de [Humboldt-Universität zu Berlin, Institut für Mathematik, Rudower Chaussee 25, Room 1.310, D12489 Berlin (Germany)

    2015-01-15

    We study the twistor equation on pseudo-Riemannian Spin{sup c}-manifolds whose solutions we call charged conformal Killing spinors (CCKSs). We derive several integrability conditions for the existence of CCKS and study their relations to spinor bilinears. A construction principle for Lorentzian manifolds admitting CCKS with nontrivial charge starting from CR-geometry is presented. We obtain a partial classification result in the Lorentzian case under the additional assumption that the associated Dirac current is normal conformal and complete the classification of manifolds admitting CCKS in all dimensions and signatures ≤5 which has recently been initiated in the study of supersymmetric field theories on curved space.

  7. Charge transfer in TATB and HMX under extreme conditions.

    Science.gov (United States)

    Zhang, Chaoyang; Ma, Yu; Jiang, Daojian

    2012-11-01

    Charge transfer is usually accompanied by structural changes in materials under different conditions. However, the charge transfer in energetic materials that are subjected to extreme conditions has seldom been explored by researchers. In the work described here, the charge transfer in single molecules and unit cells of the explosives TATB and HMX under high temperatures and high pressures was investigated by performing static and dynamic calculations using three DFT methods, including the PWC functional of LDA, and the BLYP and PBE functionals of GGA. The results showed that negative charge is transferred from the nitro groups of molecular or crystalline TATB and HMX when they are heated. All DFT calculations for the compressed TATB unit cell indicate that, generally, negative charge transfer occurs to its nitro groups as the compression increases. PWC and PBE calculations for crystalline HMX show that negative charge is first transferred to the nitro groups but, as the compression increases, the negative charge is transferred from the nitro groups. However, the BLYP calculations indicated that there was gradual negative charge transfer to the nitro groups of HMX, similar to the case for TATB. The unrelaxed state of the uniformly compressed TATB causes negative charge to be transferred from its nitro groups, in contrast to what is seen in the relaxed state. Charge transfer in TATB is predicted to occur much more easily than in HMX.

  8. Salmonella Taking Charge

    OpenAIRE

    Weigele, Bethany A.; Alto, Neal M.

    2010-01-01

    Pathogens develop creative ways to undermine host defenses. In this issue of Cell Host & Microbe, Bakowski et al. (2010) have unveiled a mechanism by which Salmonella evades lysosomal fusion by using a bacterial protein, SopB, that depletes the phagosomal membrane of negative charge.

  9. Charged Particle Optics Theory

    Czech Academy of Sciences Publication Activity Database

    Hawkes, P. W.; Lencová, Bohumila

    -, č. 6 (2006), s. 6-8 Grant - others:EC 5RP(XE) G5RD-CT-2000-00344 Institutional research plan: CEZ:AV0Z20650511 Keywords : optics of charged particles * design of ion lithography system * spot profile * the finite element method Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering www.phantomsnet.net

  10. Charged particle beams

    CERN Document Server

    Humphries, Stanley

    2013-01-01

    Detailed enough for a text and sufficiently comprehensive for a reference, this volume addresses topics vital to understanding high-power accelerators and high-brightness-charged particle beams. Subjects include stochastic cooling, high-brightness injectors, and the free electron laser. Humphries provides students with the critical skills necessary for the problem-solving insights unique to collective physics problems. 1990 edition.

  11. Charge oscillations in orbitrons

    International Nuclear Information System (INIS)

    Porto, M.; Gomes, L.C.

    1981-01-01

    A statistical model for the electron distribution in orbitrons is constructed where the effect of the end plates is considered. A comparison is made with the measured density of charge. The electromagnetic oscillations generated by orbitrons are calculated as pressure waves and the results obtained are compared with the data. (Author) [pt

  12. Charge Transport Processes in Molecular Junctions

    Science.gov (United States)

    Smith, Christopher Eugene

    Molecular electronics (ME) has evolved into a rich area of exploration that combines the fields of chemistry, materials, electronic engineering and computational modeling to explore the physics behind electronic conduction at the molecular level. Through studying charge transport properties of single molecules and nanoscale molecular materials the field has gained the potential to bring about new avenues for the miniaturization of electrical components where quantum phenomena are utilized to achieve solid state molecular device functionality. Molecular junctions are platforms that enable these studies and consist of a single molecule or a small group of molecules directly connected to electrodes. The work presented in this thesis has built upon the current understanding of the mechanisms of charge transport in ordered junctions using self-assembled monolayer (SAM) molecular thin films. Donor and acceptor compounds were synthesized and incorporated into SAMs grown on metal substrates then the transport properties were measured with conducting probe atomic force microscopy (CP-AFM). In addition to experimentally measured current-voltage (I-V) curves, the transport properties were addressed computationally and modeled theoretically. The key objectives of this project were to 1) investigate the impact of molecular structure on hole and electron charge transport, 2) understand the nature of the charge carriers and their structure-transport properties through long (films, and open opportunities to engineer improved electronic functionality into molecular devices.

  13. Charge reconstruction in large-area photomultipliers

    Science.gov (United States)

    Grassi, M.; Montuschi, M.; Baldoncini, M.; Mantovani, F.; Ricci, B.; Andronico, G.; Antonelli, V.; Bellato, M.; Bernieri, E.; Brigatti, A.; Brugnera, R.; Budano, A.; Buscemi, M.; Bussino, S.; Caruso, R.; Chiesa, D.; Corti, D.; Dal Corso, F.; Ding, X. F.; Dusini, S.; Fabbri, A.; Fiorentini, G.; Ford, R.; Formozov, A.; Galet, G.; Garfagnini, A.; Giammarchi, M.; Giaz, A.; Insolia, A.; Isocrate, R.; Lippi, I.; Longhitano, F.; Lo Presti, D.; Lombardi, P.; Marini, F.; Mari, S. M.; Martellini, C.; Meroni, E.; Mezzetto, M.; Miramonti, L.; Monforte, S.; Nastasi, M.; Ortica, F.; Paoloni, A.; Parmeggiano, S.; Pedretti, D.; Pelliccia, N.; Pompilio, R.; Previtali, E.; Ranucci, G.; Re, A. C.; Romani, A.; Saggese, P.; Salamanna, G.; Sawy, F. H.; Settanta, G.; Sisti, M.; Sirignano, C.; Spinetti, M.; Stanco, L.; Strati, V.; Verde, G.; Votano, L.

    2018-02-01

    Large-area PhotoMultiplier Tubes (PMT) allow to efficiently instrument Liquid Scintillator (LS) neutrino detectors, where large target masses are pivotal to compensate for neutrinos' extremely elusive nature. Depending on the detector light yield, several scintillation photons stemming from the same neutrino interaction are likely to hit a single PMT in a few tens/hundreds of nanoseconds, resulting in several photoelectrons (PEs) to pile-up at the PMT anode. In such scenario, the signal generated by each PE is entangled to the others, and an accurate PMT charge reconstruction becomes challenging. This manuscript describes an experimental method able to address the PMT charge reconstruction in the case of large PE pile-up, providing an unbiased charge estimator at the permille level up to 15 detected PEs. The method is based on a signal filtering technique (Wiener filter) which suppresses the noise due to both PMT and readout electronics, and on a Fourier-based deconvolution able to minimize the influence of signal distortions—such as an overshoot. The analysis of simulated PMT waveforms shows that the slope of a linear regression modeling the relation between reconstructed and true charge values improves from 0.769 ± 0.001 (without deconvolution) to 0.989 ± 0.001 (with deconvolution), where unitary slope implies perfect reconstruction. A C++ implementation of the charge reconstruction algorithm is available online at [1].

  14. Eliciting the mitochondrial unfolded protein response by nicotinamide adenine dinucleotide repletion reverses fatty liver disease in mice.

    Science.gov (United States)

    Gariani, Karim; Menzies, Keir J; Ryu, Dongryeol; Wegner, Casey J; Wang, Xu; Ropelle, Eduardo R; Moullan, Norman; Zhang, Hongbo; Perino, Alessia; Lemos, Vera; Kim, Bohkyung; Park, Young-Ki; Piersigilli, Alessandra; Pham, Tho X; Yang, Yue; Ku, Chai Siah; Koo, Sung I; Fomitchova, Anna; Cantó, Carlos; Schoonjans, Kristina; Sauve, Anthony A; Lee, Ji-Young; Auwerx, Johan

    2016-04-01

    With no approved pharmacological treatment, nonalcoholic fatty liver disease (NAFLD) is now the most common cause of chronic liver disease in Western countries and its worldwide prevalence continues to increase along with the growing obesity epidemic. Here, we show that a high-fat high-sucrose (HFHS) diet, eliciting chronic hepatosteatosis resembling human fatty liver, lowers hepatic nicotinamide adenine dinucleotide (NAD(+) ) levels driving reductions in hepatic mitochondrial content, function, and adenosine triphosphate (ATP) levels, in conjunction with robust increases in hepatic weight, lipid content, and peroxidation in C57BL/6J mice. To assess the effect of NAD(+) repletion on the development of steatosis in mice, nicotinamide riboside, a precursor of NAD(+) biosynthesis, was added to the HFHS diet, either as a preventive strategy or as a therapeutic intervention. We demonstrate that NR prevents and reverts NAFLD by inducing a sirtuin (SIRT)1- and SIRT3-dependent mitochondrial unfolded protein response, triggering an adaptive mitohormetic pathway to increase hepatic β-oxidation and mitochondrial complex content and activity. The cell-autonomous beneficial component of NR treatment was revealed in liver-specific Sirt1 knockout mice (Sirt1(hep-/-) ), whereas apolipoprotein E-deficient mice (Apoe(-/-) ) challenged with a high-fat high-cholesterol diet affirmed the use of NR in other independent models of NAFLD. Our data warrant the future evaluation of NAD(+) boosting strategies to manage the development or progression of NAFLD. © 2015 The Authors. Hepatology published by Wiley Periodicals, Inc., on behalf of the American Association for the Study of Liver Diseases.

  15. Hypothesis on skeletal muscle aging : mitochondrial adenine nucleotide translocator decreases reactive oxygen species production while preserving coupling efficiency

    Directory of Open Access Journals (Sweden)

    Philippe eDIOLEZ

    2015-12-01

    Full Text Available Mitochondrial membrane potential is the major regulator of mitochondrial functions, including coupling efficiency and production of reactive oxygen species (ROS. Both functions are crucial for cell bioenergetics. We previously presented evidences for a specific modulation of adenine nucleotide translocase (ANT appearing during aging that results in a decrease in membrane potential - and therefore ROS production – but surprisingly increases coupling efficiency under conditions of low ATP turnover. Careful study of the bioenergetic parameters (oxidation and phosphorylation rates, membrane potential of isolated mitochondria from skeletal muscles (gastrocnemius of aged and young rats revealed a remodeling at the level of the phosphorylation system, in the absence of alteration of the inner mitochondrial membrane (uncoupling or respiratory chain complexes regulation. We further observed a decrease in mitochondrial affinity for ADP in aged isolated mitochondria, and higher sensitivity of ANT to its specific inhibitor atractyloside. This age-induced modification of ANT results in an increase in the ADP concentration required to sustain the same ATP turnover as compared to young muscle, and therefore in a lower membrane potential under phosphorylating - in vivo - conditions. Thus, for equivalent ATP turnover (cellular ATP demand, coupling efficiency is even higher in aged muscle mitochondria, due to the down-regulation of inner membrane proton leak caused by the decrease in membrane potential. In the framework of the radical theory of aging, these modifications in ANT function may be the result of oxidative damage caused by intra mitochondrial ROS and may appear like a virtuous circle where ROS induce a mechanism that reduces their production, without causing uncoupling, and even leading in improved efficiency. Because of the importance of ROS as therapeutic targets, this new mechanism deserves further studies.

  16. Auxotrophic Actinobacillus pleurpneumoniae grows in multispecies biofilms without the need for nicotinamide-adenine dinucleotide (NAD) supplementation.

    Science.gov (United States)

    Loera-Muro, Abraham; Jacques, Mario; Avelar-González, Francisco J; Labrie, Josée; Tremblay, Yannick D N; Oropeza-Navarro, Ricardo; Guerrero-Barrera, Alma L

    2016-06-27

    Actinobacillus pleuropneumoniae is the etiologic agent of porcine contagious pleuropneumonia, which causes important worldwide economic losses in the swine industry. Several respiratory tract infections are associated with biofilm formation, and A. pleuropneumoniae has the ability to form biofilms in vitro. Biofilms are structured communities of bacterial cells enclosed in a self-produced polymer matrix that are attached to an abiotic or biotic surface. Virtually all bacteria can grow as a biofilm, and multi-species biofilms are the most common form of microbial growth in nature. The goal of this study was to determine the ability of A. pleuropneumoniae to form multi-species biofilms with other bacteria frequently founded in pig farms, in the absence of pyridine compounds (nicotinamide mononucleotide [NMN], nicotinamide riboside [NR] or nicotinamide adenine dinucleotide [NAD]) that are essential for the growth of A. pleuropneumoniae. For the biofilm assay, strain 719, a field isolate of A. pleuropneumoniae serovar 1, was mixed with swine isolates of Streptococcus suis, Bordetella bronchiseptica, Pasteurella multocida, Staphylococcus aureus or Escherichia coli, and deposited in 96-well microtiter plates. Based on the CFU results, A. pleuropneumoniae was able to grow with every species tested in the absence of pyridine compounds in the culture media. Interestingly, A. pleuropneumoniae was also able to form strong biofilms when mixed with S. suis, B. bronchiseptica or S. aureus. In the presence of E. coli, A. pleuropneumoniae only formed a weak biofilm. The live and dead populations, and the matrix composition of multi-species biofilms were also characterized using fluorescent markers and enzyme treatments. The results indicated that poly-N-acetyl-glucosamine remains the primary component responsible for the biofilm structure. In conclusion, A. pleuropneumoniae apparently is able to satisfy the requirement of pyridine compounds through of other swine pathogens by

  17. Adenine Enrichment at the Fourth CDS Residue in Bacterial Genes Is Consistent with Error Proofing for +1 Frameshifts.

    Science.gov (United States)

    Abrahams, Liam; Hurst, Laurence D

    2017-12-01

    Beyond selection for optimal protein functioning, coding sequences (CDSs) are under selection at the RNA and DNA levels. Here, we identify a possible signature of "dual-coding," namely extensive adenine (A) enrichment at bacterial CDS fourth sites. In 99.07% of studied bacterial genomes, fourth site A use is greater than expected given genomic A-starting codon use. Arguing for nucleotide level selection, A-starting serine and arginine second codons are heavily utilized when compared with their non-A starting synonyms. Several models have the ability to explain some of this trend. In part, A-enrichment likely reduces 5' mRNA stability, promoting translation initiation. However T/U, which may also reduce stability, is avoided. Further, +1 frameshifts on the initiating ATG encode a stop codon (TGA) provided A is the fourth residue, acting either as a frameshift "catch and destroy" or a frameshift stop and adjust mechanism and hence implicated in translation initiation. Consistent with both, genomes lacking TGA stop codons exhibit weaker fourth site A-enrichment. Sequences lacking a Shine-Dalgarno sequence and those without upstream leader genes, that may be more error prone during initiation, have greater utilization of A, again suggesting a role in initiation. The frameshift correction model is consistent with the notion that many genomic features are error-mitigation factors and provides the first evidence for site-specific out of frame stop codon selection. We conjecture that the NTG universal start codon may have evolved as a consequence of TGA being a stop codon and the ability of NTGA to rapidly terminate or adjust a ribosome. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  18. Differential effects of adenine nucleotide analogues on shape change and aggregation induced by adnosine 5-diphosphate (ADP) in human platelets.

    Science.gov (United States)

    Park, H S; Hourani, S M

    1999-07-01

    Adenosine 5'-diphosphate (ADP) induces human blood platelets to aggregate and change shape, and it has been suggested that these two responses are mediated by more than one subtype of ADP receptor. The structure-activity relationships for several analogues of adenine nucleotides in causing aggregation and shape change were measured and compared in washed platelets using an aggregometer. ADP and its analogues 2-methylthioadenosine 5'-diphosphate (2-methylthio-ADP), adenosine 5'(alpha,beta-methylene)diphosphonate (AMPCP), S(P)-adenosine 5'-O-(1-thiodiphosphate) (AD-P alphaS) and adenosine 5'-O-(2-thiodiphosphate) (ADPbetaS) were used as agonists. Adenosine 5'-triphosphate (ATP) and its analogues, P1, P5-diadenosine pentaphosphate (ApsA), adenosine (5'-(alpha,beta-methylene)triphosphonate (AMPCPP), 2-methylthioadenosine 5'-triphosphate (2-methylthio-ATP) and uridine 5'-triphosphate (UTP), as well as the trypanocidal drug suramin, were used as antagonists. In general, the structure-activity relationships for both responses were similar, but for some analogues differences were observed. ADPalphaS and ADPbetaS were much more potent agonists relative to ADP for shape change than for aggregation and indeed ADPalphaS antagonized ADP-induced aggregation with an apparent pK(B) value of 5.5+/-0.1. 2-Methylthio-ATP also had different effects in aggregation and shape change, being a much higher affinity antagonist of aggregation than of shape change with an apparent pK(B) value of 7.0+/-0.2 for aggregation and 5.2+/-0.2 for shape change. These results support the suggestion that these two responses are mediated by multiple ADP receptors on human platelets, and are consistent with shape change being mediated via one receptor (the P2Y1 receptor) with aggregation requiring the activation of two receptors (the P2Y1 and another P2Y receptor).

  19. Signal-enhanced electrochemiluminescence immunosensor based on synergistic catalysis of nicotinamide adenine dinucleotide hydride and silver nanoparticles.

    Science.gov (United States)

    Wang, Guangjie; Jin, Feng; Dai, Nan; Zhong, Zhaoyang; Qing, Yi; Li, Mengxia; Yuan, Ruo; Wang, Dong

    2012-03-01

    A new metal-organic nanocomposite with synergistic catalysis function was prepared and developed to construct an electrochemiluminescence (ECL) immunosensor for ultrasensitive detection of tumor biomarker CA125. Silver nanoparticles (AgNPs) and nicotinamide adenine dinucleotide hydride (NADH) that can participate and catalyze the ECL reaction of Ru(bpy)(3)(2+) were employed as the metal component and the organic component to synthesize the metal-organic nanocomposite of NADH-AgNPs (NA). The novel ECL immunosensor was assembled via Ru(bpy)(3)(2+)-doped silica nanoparticles (Ru-SiO(2)) modified electrode with the NA as immune labels. First, the chitosan-suspended Ru-SiO(2) nanoparticles were cast on the gold electrode surface to immobilize the ECL probes of Ru(bpy)(3)(2+) and link gold nanoparticles. Then, the primary antibodies were loaded onto the modified electrode via the gold sulfhydryl covalent binding. After immunobinding the analytes of antigen, NA-attached secondary antibodies could be captured as a sandwich type on the electrode. Finally, based on the circularly synergistic catalysis by the silver and NADH for the solid-phase ECL of Ru(bpy)(3)(2+), the proposed immunosensor sensed the concentration of antigen. The synergistic ECL catalysis of metal-organic nanocomposite amplified response signal and pushed the detection limit down to 0.03 U ml(-1), which initiated a new ECL labeling field and has great significance for ECL immunoassays. Copyright © 2012 Elsevier Inc. All rights reserved.

  20. Relative abundances of primary ion radicals in γ-irradiated DNA: Cytosine vs thymine anions and guanine vs adenine cations

    International Nuclear Information System (INIS)

    Sevilla, M.D.; Becker, D.; Yan, Mengyao; Summerfield, S.R.

    1991-01-01

    An ESR study of the relative distribution of ion radicals formed in DNA equilibrated with D 2 O and γ-irradiated at 77 K is presented. The ESR spectra of irradiated DNA and polynucleotides (poly[dG]·poly[dC] and poly[dAdT]·poly[dAdT]) were obtained and employed in a computer-assisted analysis for the individual ion-radical distribution. Analysis of spectra as a function of power allowed the separation of the spectra of the pyrimidine anions (T sm-bullet- , C sm-bullet- ) from the spectra of the purine cations (G sm-bullet+ , A sm-bullet+ ). The spectra of the mononucleotide ion radicals, dCMP sm-bullet- , dTMP sm-bullet- , dGMP sm-bullet+ , and dAMP sm-bullet+ , were produced in 8 M LiCl glasses. In addition, the spectra of the ion radicals of all of the mononucleotide ion radicals except dAMP + were simulated by using hyperfine and g tensors from the literature. Basis spectra derived from (1) power saturation experiments, (2) polynucleotide and mononucleotide spectra, (3) spectra of mononucleotides alone, and (4) anisotropic simulations were used to fit the spectra of DNA by use of a linear least-squares analysis. Each of the four separate analyses confirms that the cytosine anion dominates the spectra of DNA at 100 K. Three analyses included the cationic composition, and they strongly favor the guanine cation over the adenine cation. An average of the authors results gives the DNA ion radicals' relative to abundances as ca. 77% C sm-bullet- , 23% T sm-bullet- for the anions and >90% G sm-bullet+ for the cations about equal amounts of anions and cations are present. No difference in results is found for DNA irradiated in frozen D 2 O solutions or simply exchanged at 100% D 2 O humidity

  1. Morphological features, distribution and compartmental organization of the nicotinamide adenine dinucleotide phosphate reduced-diaphorase interneurons in the human striatum.

    Science.gov (United States)

    Bernácer, Javier; Prensa, Lucía; Giménez-Amaya, José Manuel

    2005-08-29

    Striatal nicotinamide adenine dinucleotide phosphate reduced-diaphorase (NADPH-d)-positive (+) cells are one of the major classes of striatal interneurons. The present study analyzes their somatodendritic morphology, distribution pattern, and compartmental organization in the caudate nucleus (CN) and putamen (Put) of nine normal human brains. The following striatal territories are examined: 1) the precommissural head of the CN; 2) the postcommissural head of the CN; 3) the body of the CN; 4) the gyrus of the CN; 5) the tail of the CN; 6) the precommissural Put; and 7) the postcommissural Put. Three morphologically distinct types of NADPH-d+ neurons were found in each of these territories. The two most common NADPH-d+ neurons displayed an ovoid or triangular perikaryon from which several thick primary dendrites emerged, although much less numerous, bipolar-shaped NADPH-d+ cells were also observed. The highest density of NADPH-d+ neurons was found in the gyrus of the CN, followed by the body of the CN, tail of the CN, postcommissural head of the CN, postcommissural Put, precommissural head of the CN, and precommissural Put. The matrix was the striatal compartment with the densest NADPH-d+ neuronal population. Some of these cells also occurred in the center and peripheral regions of the striosomes located in the head of the CN and in the Put. In the body and gyrus of the CN, the striosomes were largely devoid of these striatal interneurons. Knowledge of the density and distribution of these interneurons should advance our understanding of the organization of the normal human striatum and help to evaluate the effects of neurodegenerative processes on cell density. (c) 2005 Wiley-Liss, Inc.

  2. Cellular properties of human erythrocytes preserved in saline-adenine-glucose-mannitol in the presence of L-carnitine.

    Science.gov (United States)

    Arduini, Arduino; Minetti, Giampaolo; Ciana, Annarita; Seppi, Claudio; Brovelli, Augusta; Profumo, Antonella; Vercellati, Cristina; Zappa, Manuela; Zanella, Alberto; Dottori, Secondo; Bonomini, Mario

    2007-01-01

    L-Carnitine (LC) in the preservation medium during storage of red blood cells (RBC) can improve the mean 24-hr percent recovery in vivo and increase RBC life-span after reinfusion. The purpose of the study was to investigate the differences in the biochemical properties of RBCs stored in the presence or absence of LC, and the cell-age related responses to storage conditions and to LC. RBC concentrates in saline-adenine-glucose-mannitol (SAG-M) were stored in the presence or absence of 5 mM LC at 4 degrees C for up to 8 weeks. RBC subpopulations of different densities were prepared by centrifugation on Stractan density gradient. Cells were sampled at 0, 3, 6, and 8 weeks, and hematological and cellular properties analyzed (MCV, MCHC, 4.1a/4.1b ratio as a cell age parameter, intracellular Na(+) and K(+)). After 6 weeks, MCV of RBC stored in the presence of LC was lower than that of controls (6 weeks MCV: controls 95.4 +/- 1.8 fl; LC 91.5 +/- 2.0 fl; n = 6; P < 0.005). This was due to swelling of control cells, and affected mainly older RBCs. LC appeared to reduce or retard cell swelling. Among the osmotically active substances whose changes during storage could contribute to cell swelling, only intracellular Na(+) and K(+) differed between stored control RBCs and LC-treated cells. LC reduces the swelling of older cells during storage at 4 degrees C in SAG-M, possibly by acting on the permeability of cell membrane to monovalent cations.

  3. Effect of charged line defects on conductivity in graphene: Numerical Kubo and analytical Boltzmann approaches

    DEFF Research Database (Denmark)

    Radchenko, T. M.; Shylau, A. A.; Zozoulenko, I. V.

    2013-01-01

    Charge carrier transport in single-layer graphene with one-dimensional charged defects is studied theoretically. Extended charged defects, considered an important factor for mobility degradation in chemically vapor-deposited graphene, are described by a self-consistent Thomas-Fermi potential...

  4. Intramembrane charge movement in frog skeletal muscle fibres. Properties of charge 2.

    Science.gov (United States)

    Brum, G; Rios, E

    1987-06-01

    1. Membrane currents were measured in cut skeletal muscle fibres voltage-clamped in a double Vaseline gap in solutions that had impermeant ions substituted for Na+, K+ and Cl-. The fibres were maintained at a holding potential of 0 mV. Pulses to positive voltages elicited outward currents that were proportional to voltage at all times; these were used to estimate linear capacitive currents, which in turn were used in the construction of non-linear current transients. 2. Large negative-going pulses elicited proportionally larger inward currents that decayed during the pulse with voltage-dependent kinetics. A portion of the non-linear current could be eliminated by solutions containing EGTA, as well as by large negative conditioning pulses of 200 ms or more. This portion was probably an inward Ca2+ current. 3. The non-linear current remaining in EGTA-containing solutions had characteristics of intramembrane charge movement ('charge 2'). This charge depended on voltage according to a two-state Boltzmann function of average parameters Qmax = 47.7 nC/microF, V = -115 mV, K = 21.5 mV (seven fibres). 4. The charge movement current transients were single-exponential decays (after a short rising phase) with time constants (tau) that depended on voltage (V). A single-barrier Eyring rate model described well the dependence of time constant on voltage. This fit permitted an independent estimate of a transition voltage, V, and a slope parameter K related to apparent valence of the mobile particle. The values of V and K that best fitted the kinetic data were close to the corresponding values estimated from the charge vs. voltage distribution. 5. Effective capacitance was measured by the transfer of capacitive charge by a small pulse superimposed on a variable pre-pulse. The capacitance was found to depend on pre-pulse voltage. The voltage dependence of the capacitance was as expected from the properties of charge 2 measured independently in the same fibres. 6. The presence of

  5. Charged particle confinement in magnetic mirror

    International Nuclear Information System (INIS)

    Bora, D.; John, P.I.; Saxena, Y.C.; Varma, R.K.

    1982-01-01

    The behaviour of single charged particle trapped in a magnetic mirror has been investigated experimentally. The particle injected off axis and trapped in a magnetic mirror, leak out of the mirror with the leakage characterized by multiple decay times. The observed decay times are in good agreement with predictions of a ''wave mechanical like'' model by Varma, over a large range of relevant parameters. (author)

  6. Versatile charge transfer through anthraquinone films for electrochemical sensing applications

    Energy Technology Data Exchange (ETDEWEB)

    Venarusso, Luna B. [Department of Chemistry, Universidade Federal de Mato Grosso do Sul, Caixa Postal 549, Campo Grande, MS 79070-900 (Brazil); Tammeveski, Kaido [Institute of Chemistry, University of Tartu, Ravila 14a, 50411 Tartu (Estonia); Maia, Gilberto, E-mail: gilberto.maia@ufms.br [Department of Chemistry, Universidade Federal de Mato Grosso do Sul, Caixa Postal 549, Campo Grande, MS 79070-900 (Brazil)

    2011-10-01

    Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were employed to study the effect of anthraquinone (AQ) films on the charge transfer rate of {beta}-nicotinamide adenine dinucleotide (NAD{sup +}), dopamine (DA), and ferricyanide on glassy carbon (GC) electrodes in solutions of different pH. Maximum blocking action on the Fe(CN){sub 6}{sup 3-} redox probe was observed at pH 7 and open-circuit potential (OCP). However, maximum electron hopping effect was observed at pH 9 at both -0.58 V and -0.85 V for Fe(CN){sub 6}{sup 3-}, pH 7 at -0.58 V for NAD{sup +}, and pH 9 at -0.58 V for DA, suggesting that electron hopping in AQ films on a GC surface is dependent on both pH and electrode potential. These findings lend support for the application of these films in the detection of soluble redox probes such as NAD{sup +} and DA at biological pH values (from 7 to 9).

  7. Versatile charge transfer through anthraquinone films for electrochemical sensing applications

    International Nuclear Information System (INIS)

    Venarusso, Luna B.; Tammeveski, Kaido; Maia, Gilberto

    2011-01-01

    Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were employed to study the effect of anthraquinone (AQ) films on the charge transfer rate of β-nicotinamide adenine dinucleotide (NAD + ), dopamine (DA), and ferricyanide on glassy carbon (GC) electrodes in solutions of different pH. Maximum blocking action on the Fe(CN) 6 3- redox probe was observed at pH 7 and open-circuit potential (OCP). However, maximum electron hopping effect was observed at pH 9 at both -0.58 V and -0.85 V for Fe(CN) 6 3- , pH 7 at -0.58 V for NAD + , and pH 9 at -0.58 V for DA, suggesting that electron hopping in AQ films on a GC surface is dependent on both pH and electrode potential. These findings lend support for the application of these films in the detection of soluble redox probes such as NAD + and DA at biological pH values (from 7 to 9).

  8. Accurate Charge Densities from Powder Diffraction

    DEFF Research Database (Denmark)

    Bindzus, Niels; Wahlberg, Nanna; Becker, Jacob

    Synchrotron powder X-ray diffraction has in recent years advanced to a level, where it has become realistic to probe extremely subtle electronic features. Compared to single-crystal diffraction, it may be superior for simple, high-symmetry crystals owing to negligible extinction effects and minimal...... peak overlap. Additionally, it offers the opportunity for collecting data on a single scale. For charge densities studies, the critical task is to recover accurate and bias-free structure factors from the diffraction pattern. This is the focal point of the present study, scrutinizing the performance...

  9. Comprehensive decay law for emission of charged particles and ...

    Indian Academy of Sciences (India)

    2014-04-07

    Apr 7, 2014 ... the case of alpha, cluster and proton decays are presented together. It is seen that, all of them fall in a single straight line with a common value for slope and intercept. This shows how the decays of charged particles of any Z values from heavy nuclei are governed by a single rule of law, namely, the linear ...

  10. Simulations of charge transport in organic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Vehoff, Thorsten

    2010-05-05

    We study the charge transport properties of organic liquid crystals, i.e. hexabenzocoronene and carbazole macrocycle, and single crystals, i.e. rubrene, indolocarbazole and benzothiophene derivatives (BTBT, BBBT). The aim is to find structure-property relationships linking the chemical structure as well as the morphology with the bulk charge carrier mobility of the compounds. To this end, molecular dynamics (MD) simulations are performed yielding realistic equilibrated morphologies. Partial charges and molecular orbitals are calculated based on single molecules in vacuum using quantum chemical methods. The molecular orbitals are then mapped onto the molecular positions and orientations, which allows calculation of the transfer integrals between nearest neighbors using the molecular orbital overlap method. Thus we obtain realistic transfer integral distributions and their autocorrelations. In case of organic crystals the differences between two descriptions of charge transport, namely semi-classical dynamics (SCD) in the small polaron limit and kinetic Monte Carlo (KMC) based on Marcus rates, are studied. The liquid crystals are investigated solely in the hopping limit. To simulate the charge dynamics using KMC, the centers of mass of the molecules are mapped onto lattice sites and the transfer integrals are used to compute the hopping rates. In the small polaron limit, where the electronic wave function is spread over a limited number of neighboring molecules, the Schroedinger equation is solved numerically using a semi-classical approach. The carbazole macrocycles form columnar structures arranged on a hexagonal lattice with side chains facing inwards, so columns can closely approach each other allowing inter-columnar and thus three-dimensional transport. We are able to show that, on the time-scales of charge transport, static disorder due to slow side chain motions is the main factor determining the mobility. The high mobility of rubrene is explained by two main

  11. Measurement of Neutrino Induced, Charged Current, Charged Pion Production

    Energy Technology Data Exchange (ETDEWEB)

    Wilking, Michael Joseph [Univ. of Colorado, Boulder, CO (United States)

    2009-05-01

    Neutrinos are among the least understood particles in the standard model of particle physics. At neutrino energies in the 1 GeV range, neutrino properties are typically determined by observing the outgoing charged lepton produced in a charged current quasi-elastic interactions. The largest charged current background to these measurements comes from charged current pion production interactions, for which there is very little available data.

  12. The quasilocalized charge approximation

    International Nuclear Information System (INIS)

    Kalman, G J; Golden, K I; Donko, Z; Hartmann, P

    2005-01-01

    The quasilocalized charge approximation (QLCA) has been used for some time as a formalism for the calculation of the dielectric response and for determining the collective mode dispersion in strongly coupled Coulomb and Yukawa liquids. The approach is based on a microscopic model in which the charges are quasilocalized on a short-time scale in local potential fluctuations. We review the conceptual basis and theoretical structure of the QLC approach and together with recent results from molecular dynamics simulations that corroborate and quantify the theoretical concepts. We also summarize the major applications of the QLCA to various physical systems, combined with the corresponding results of the molecular dynamics simulations and point out the general agreement and instances of disagreement between the two

  13. High Voltage Charge Pump

    KAUST Repository

    Emira, Ahmed A.

    2014-10-09

    Various embodiments of a high voltage charge pump are described. One embodiment is a charge pump circuit that comprises a plurality of switching stages each including a clock input, a clock input inverse, a clock output, and a clock output inverse. The circuit further comprises a plurality of pumping capacitors, wherein one or more pumping capacitors are coupled to a corresponding switching stage. The circuit also comprises a maximum selection circuit coupled to a last switching stage among the plurality of switching stages, the maximum selection circuit configured to filter noise on the output clock and the output clock inverse of the last switching stage, the maximum selection circuit further configured to generate a DC output voltage based on the output clock and the output clock inverse of the last switching stage.

  14. Interaction between heterogeneously charged surfaces: surface patches and charge modulation.

    Science.gov (United States)

    Ben-Yaakov, Dan; Andelman, David; Diamant, Haim

    2013-02-01

    When solid surfaces are immersed in aqueous solutions, some of their charges can dissociate and leave behind charged patches on the surface. Although the charges are distributed heterogeneously on the surface, most of the theoretical models treat them as homogeneous. For overall non-neutral surfaces, the assumption of surface charge homogeneity is rather reasonable since the leading terms of two such interacting surfaces depend on the nonzero average charge. However, for overall neutral surfaces the nature of the surface charge distribution is crucial in determining the intersurface interaction. In the present work we study the interaction between two charged surfaces across an aqueous solution for several charge distributions. The analysis is preformed within the framework of the linearized Poisson-Boltzmann theory. For periodic charge distributions the interaction is found to be repulsive at small separations, unless the two surface distributions are completely out-of-phase with respect to each other. For quenched random charge distributions we find that due to the presence of the ionic solution in between the surfaces, the intersurface repulsion dominates over the attraction in the linear regime of the Poisson-Boltzmann theory. The effect of quenched charge heterogeneity is found to be particularly substantial in the case of large charged domains.

  15. Charged particle analyzer PLAZMAG

    International Nuclear Information System (INIS)

    Apathy, Istvan; Endroeczy, Gabor; Szemerey, Istvan; Szendroe, Sandor

    1985-01-01

    The scientific task of the charged particle analyzer PLAZMAG, a part of the VEGA space probe, and the physical background of the measurements are described. The sensor of the device face the Sun and the comet Halley measuring the energy and mass spectrum of ion and electron components of energies lower than 25 keV. The tasks of the individual electronic parts, the design aspects and the modes of operation in different phases of the flight are dealt with. (author)

  16. Hidden charged dark matter

    International Nuclear Information System (INIS)

    Feng, Jonathan L.; Kaplinghat, Manoj; Tu, Huitzu; Yu, Hai-Bo

    2009-01-01

    Can dark matter be stabilized by charge conservation, just as the electron is in the standard model? We examine the possibility that dark matter is hidden, that is, neutral under all standard model gauge interactions, but charged under an exact (\\rm U)(1) gauge symmetry of the hidden sector. Such candidates are predicted in WIMPless models, supersymmetric models in which hidden dark matter has the desired thermal relic density for a wide range of masses. Hidden charged dark matter has many novel properties not shared by neutral dark matter: (1) bound state formation and Sommerfeld-enhanced annihilation after chemical freeze out may reduce its relic density, (2) similar effects greatly enhance dark matter annihilation in protohalos at redshifts of z ∼ 30, (3) Compton scattering off hidden photons delays kinetic decoupling, suppressing small scale structure, and (4) Rutherford scattering makes such dark matter self-interacting and collisional, potentially impacting properties of the Bullet Cluster and the observed morphology of galactic halos. We analyze all of these effects in a WIMPless model in which the hidden sector is a simplified version of the minimal supersymmetric standard model and the dark matter is a hidden sector stau. We find that charged hidden dark matter is viable and consistent with the correct relic density for reasonable model parameters and dark matter masses in the range 1 GeV ∼ X ∼< 10 TeV. At the same time, in the preferred range of parameters, this model predicts cores in the dark matter halos of small galaxies and other halo properties that may be within the reach of future observations. These models therefore provide a viable and well-motivated framework for collisional dark matter with Sommerfeld enhancement, with novel implications for astrophysics and dark matter searches

  17. Adsorption of DNA/RNA nucleobases onto single-layer MoS2 and Li-Doped MoS2: A dispersion-corrected DFT study

    Science.gov (United States)

    Sadeghi, Meisam; Jahanshahi, Mohsen; Ghorbanzadeh, Morteza; Najafpour, Ghasem

    2018-03-01

    The kind of sensing platform in nano biosensor plays an important role in nucleic acid sequence detection. It has been demonstrated that graphene does not have an intrinsic band gap; therefore, transition metal dichalcogenides (TMDs) are desirable materials for electronic base detection. In the present work, a comparative study of the adsorption of the DNA/RNA nucleobases [Adenine (A), Cytosine (C) Guanine (G), Thymine (T) and Uracil (U)] onto the single-layer molybdenum disulfide (MoS2) and Li-doped MoS2 (Li-MoS2) as a sensing surfaces was investigated by using Dispersion-corrected Density Functional Theory (D-DFT) calculations and different measure of equilibrium distances, charge transfers and binding energies for the various nucleobases were calculated. The results revealed that the interactions between the nucleobases and the MoS2 can be strongly enhanced by introducing metal atom, due to significant charge transfer from the Li atom to the MoS2 when Lithium is placed on top of the MoS2. Furthermore, the binding energies of the five nucleobases were in the range of -0.734 to -0.816 eV for MoS2 and -1.47 to -1.80 eV for the Li-MoS2. Also, nucleobases were adsorbed onto MoS2 sheets via the van der Waals (vdW) force. This high affinity and the renewable properties of the biosensing platform demonstrated that Li-MoS2 nanosheet is biocompatible and suitable for nucleic acid analysis.

  18. Search for fractional charge

    International Nuclear Information System (INIS)

    Turner, R.E.

    1984-01-01

    A search was made for fractional charges of the form Z plus two-thirds e, where Z is an integer. It was assumed that the charges exist in natural form bound with other fractional charges in neutral molecules. It was further assumed that these neutral molecules are present in air. Two concentration schemes were employed. One sample was derived from the waste gases from a xenon distillation plant. This assumes that high mass, low vapor pressure components of air are concentrated along with the xenon. The second sample involved ionizing air, allowing a brief recombination period, and then collecting residual ions on the surface of titanium discs. Both samples were analyzed at the University of Rochester in a system using a tandem Van de Graff to accelerate particles through an essentially electrostatic beam handling system. The detector system employed both a Time of Flight and an energy-sensitive gas ionization detector. In the most sensitive mode of analysis, a gas absorber was inserted in the beam path to block the intense background. The presence of an absorber limited the search to highly penetrating particles. Effectively, this limited the search to particles with low Z and masses greater than roughly fifty GeV. The final sensitivities attained were on the order of 1 x 10 -20 for the ionized air sample and 1 x 10 -21 for the gas sample. A discussion of the caveats that could reduce the actual level of sensitivity is included

  19. Proximity effect and charging in mesoscopic normal metal-superconductor junction systems

    International Nuclear Information System (INIS)

    Bruder, C.; Fazio, R.; Schoen, G.

    1994-01-01

    The proximity effect influences the transport properties of normal metal-superconductor heterostructures. If these systems are small they exhibit pronounced charging effects. We show that charging suppresses the proximity effect. The effect can be made visible since the charging energy and hence the proximity effect can be modulated by gate voltages. We derive these results in a unified formulation which also describes single electron tunneling, Andreev reflection and the supercurrent through normal-superconductor systems in the presence of charging effects. (orig.)

  20. Genetics Home Reference: CHARGE syndrome

    Science.gov (United States)

    ... combination of major and minor characteristics. The major characteristics of CHARGE syndrome are common in this disorder and occur less ... and unusually shaped external ears. While the minor characteristics of CHARGE syndrome are common in this disorder, they are also ...

  1. Pion double charge exchange in the Δ33 resonance region

    International Nuclear Information System (INIS)

    Wirzba, A.; Toki, H.; Siciliano, E.R.; Johnson, M.B.; Gilman, R.

    1989-01-01

    We examine the model dependence and nuclear-structure sensitivity of several Δ 33 -dominated processes contributing to pion double charge exchange on nuclei in the region of the Δ 33 resonance. These processes include the Δ 33 -nucleon interaction V NΔ and sequential scattering, in which the pion undergoes single charge exchange on two different nucleons. In all cases, the scattering takes place through the exchange of an intermediate π and ρ meson. Sequential-mediated double charge exchange is found to be only moderately sensitive to short-range correlations, meson-nucleon form factors, and the rho meson, whereas V NΔ -mediated double charge exchange is very sensitive to all these effects. Results are given for double charge exchange on 18 O (double isobaric analog transitions) and 16 O (nonanalog transitions). Sequential double charge exchange is shown to favor non-spin-flip matrix elements of the transition operator whereas V NΔ -mediated double charge exchange favors spin-flip matrix elements. The energy dependence of the zero-degree cross sections for V NΔ and sequential scattering are also different: Sequential tends to increase monotonically from 100 to 300 MeV, whereas V NΔ peaks at about 150 MeV. The delta-nucleon interaction is found likely to dominate over sequential scattering in nonanalog double charge exchange. The V NΔ is also large in analog double charge exchange, but it does not enable us to explain the anomalous behavior of the 18 O differential cross sections

  2. Improving Charging-Breeding Simulations with Space-Charge Effects

    Science.gov (United States)

    Bilek, Ryan; Kwiatkowski, Ania; Steinbrügge, René

    2016-09-01

    Rare-isotope-beam facilities use Highly Charged Ions (HCI) for accelerators accelerating heavy ions and to improve measurement precision and resolving power of certain experiments. An Electron Beam Ion Trap (EBIT) is able to create HCI through successive electron impact, charge breeding trapped ions into higher charge states. CBSIM was created to calculate successive charge breeding with an EBIT. It was augmented by transferring it into an object-oriented programming language, including additional elements, improving ion-ion collision factors, and exploring the overlap of the electron beam with the ions. The calculation is enhanced with the effects of residual background gas by computing the space charge due to charge breeding. The program assimilates background species, ionizes and charge breeds them alongside the element being studied, and allows them to interact with the desired species through charge exchange, giving fairer overview of realistic charge breeding. Calculations of charge breeding will be shown for realistic experimental conditions. We reexamined the implementation of ionization energies, cross sections, and ion-ion interactions when charge breeding.

  3. Charge orders in organic charge-transfer salts

    Science.gov (United States)

    Kaneko, Ryui; Tocchio, Luca F.; Valentí, Roser; Becca, Federico

    2017-10-01

    Motivated by recent experimental suggestions of charge-order-driven ferroelectricity in organic charge-transfer salts, such as κ-(BEDT-TTF)2Cu[N(CN)2]Cl, we investigate magnetic and charge-ordered phases that emerge in an extended two-orbital Hubbard model on the anisotropic triangular lattice at 3/4 filling. This model takes into account the presence of two organic BEDT-TTF molecules, which form a dimer on each site of the lattice, and includes short-range intramolecular and intermolecular interactions and hoppings. By using variational wave functions and quantum Monte Carlo techniques, we find two polar states with charge disproportionation inside the dimer, hinting to ferroelectricity. These charge-ordered insulating phases are stabilized in the strongly correlated limit and their actual charge pattern is determined by the relative strength of intradimer to interdimer couplings. Our results suggest that ferroelectricity is not driven by magnetism, since these polar phases can be stabilized also without antiferromagnetic order and provide a possible microscopic explanation of the experimental observations. In addition, a conventional dimer-Mott state (with uniform density and antiferromagnetic order) and a nonpolar charge-ordered state (with charge-rich and charge-poor dimers forming a checkerboard pattern) can be stabilized in the strong-coupling regime. Finally, when electron–electron interactions are weak, metallic states appear, with either uniform charge distribution or a peculiar 12-site periodicity that generates honeycomb-like charge order.

  4. Molecular recognition of AT-DNA sequences by the induced CD pattern of dibenzotetraaza[14]annulene (DBTAA)–adenine derivatives

    OpenAIRE

    Stojković, Marijana Radić; Škugor, Marko; Dudek, Łukasz; Grolik, Jarosław; Eilmes, Julita; Piantanida, Ivo

    2014-01-01

    Summary An investigation of the interactions of two novel and several known DBTAA–adenine conjugates with double-stranded DNA and RNA has revealed the DNA/RNA groove as the dominant binding site, which is in contrast to the majority of previously studied DBTAA analogues (DNA/RNA intercalators). Only DBTAA–propyladenine conjugates revealed the molecular recognition of AT-DNA by an ICD band pattern > 300 nm, whereas significant ICD bands did not appear for other ds-DNA/RNA. A structure–activity...

  5. Detecting monopole charge in Weyl semimetals via quantum interference transport

    Science.gov (United States)

    Dai, Xin; Lu, Hai-Zhou; Shen, Shun-Qing; Yao, Hong

    2016-04-01

    Topological Weyl semimetals can host Weyl nodes with monopole charges in momentum space. How to detect the signature of the monopole charges in quantum transport remains a challenging topic. Here, we reveal the connection between the parity of monopole charge in topological semimetals and the quantum interference corrections to the conductivity. We show that the parity of monopole charge determines the sign of the quantum interference correction, with odd and even parity yielding the weak antilocalization and weak localization effects, respectively. This is attributed to the Berry phase difference between time-reversed trajectories circulating the Fermi sphere that encloses the monopole charges. From standard Feynman diagram calculations, we further show that the weak-field magnetoconductivity at low temperatures is proportional to +√{B } in double-Weyl semimetals and -√{B } in single-Weyl semimetals, respectively, which could be verified experimentally.

  6. Transition density of charge-exchange processes

    International Nuclear Information System (INIS)

    Lovas, R.G.

    1983-01-01

    The transition density between parent and analogue states is studied with special reference to its role in charge-exchange nuclear reactions. The structure of the target nucleus is described in a perturbative approach, in which the Coulomb and asymmetry potentials mix the eigenstates of a charge-independent single-particle Hamiltonian. In this model formulae are derived for the transition density, the Coulomb displacement energy and the neutron-proton density difference, and their relationship is used to estimate the transition density. This estimate shows that: the largest contribution comes from the density of the excess neutrons; the weight of the Coulomb-mixing effect is small up to excess neutron number 10, and grows rapidly beyond; the weight of the core polarization term induced by the excess neutrons is modest and is the same for all nuclei. It is indicated that the Coulomb effect may explain the departure from the Lane model of nucleon charge-exchange scattering found for heavy nuclei, whereas the core polarization may account for the observed anomalous dependence of the deg 0 pion charge-exchange cross section on the number of excess neutrons. (author)

  7. Theory of charged impurity scattering in two dimensional graphene

    OpenAIRE

    Adam, S.; Hwang, E. H.; Rossi, E.; Sarma, S. Das

    2008-01-01

    We review the physics of charged impurities in the vicinity of graphene. The long-range nature of Coulomb impurities affects both the nature of the ground state density profile as well as graphene's transport properties. We discuss the screening of a single Coulomb impurity and the ensemble averaged density profile of graphene in the presence of many randomly distributed impurities. Finally, we discuss graphene's transport properties due to scattering off charged impurities both at low and hi...

  8. Multiferroicity of carbon-based charge-transfer magnets.

    Science.gov (United States)

    Qin, Wei; Gong, Maogang; Chen, Xiaomin; Shastry, Tejas A; Sakidja, Ridwan; Yuan, Guoliang; Hersam, Mark C; Wuttig, Manfred; Ren, Shenqiang

    2015-01-27

    A new type of carbon charge-transfer magnet, consisting of a fullerene acceptor and single-walled carbon nanotube donor, is demonstrated, which exhibits room temperature ferromagnetism and magnetoelectric (ME) coupling. In addition, external stimuli (electric/magnetic/elastic field) and the concentration of a nanocarbon complex enable the tunabilities of the magnetization and ME coupling due to the control of the charge transfer. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Quantum theory of space charge limited current in solids

    Energy Technology Data Exchange (ETDEWEB)

    González, Gabriel, E-mail: gabriel.gonzalez@uaslp.mx [Cátedras Conacyt, Universidad Autónoma de San Luis Potosí, San Luis Potosí 78000, Mexico and Coordinación para la Innovación y la Aplicación de la Ciencia y la Tecnología, Universidad Autónoma de San Luis Potosí, San Luis Potosí 78000 (Mexico)

    2015-02-28

    We present a quantum model of space charge limited current transport inside trap-free solids with planar geometry in the mean field approximation. We use a simple transformation which allows us to find the exact analytical solution for the steady state current case. We use our approach to find a Mott-Gurney like behavior and the mobility for single charge carriers in the quantum regime in solids.

  10. Antiproton charge radius

    Science.gov (United States)

    Crivelli, P.; Cooke, D.; Heiss, M. W.

    2016-09-01

    The upcoming operation of the extra low energy antiprotons ring at CERN, the upgrade of the antiproton decelerator (AD), and the installation in the AD hall of an intense slow positron beam with an expected flux of 1 08 e+ /s will open the possibility for new experiments with antihydrogen (H ¯). Here we propose a scheme to measure the Lamb shift of H ¯. For four months of data taking, we anticipate an uncertainty of 100 ppm. This will provide a test of C P T and the first determination of the antiproton charge radius at the level of 10%.

  11. Charging C60 islands with the AFM tip

    Science.gov (United States)

    Hoff, Brice; Henry, Claude R.; Barth, Clemens

    2015-12-01

    We show that electrons can be transferred on demand from an AFM tip into single bulk-like C60 islands, which are supported on the insulating NaCl(001) surface. We exemplify this by controlled charge-manipulation experiments conducted in ultrahigh vacuum by noncontact AFM (nc-AFM), electrostatic force microscopy (EFM) and Kelvin probe force microscopy (KPFM). KPFM shows a homogeneous contrast at the islands, which is a signature for an equal distribution of the electrons in the T1u band. The charge dissipates during half a day due to an interaction of the charged C60 islands with defects in the near surface region of NaCl. Our results open the perspective in photo-voltaics to study charge attachment, stability and charge exchange with the environment of any C60 bulk-like system.We show that electrons can be transferred on demand from an AFM tip into single bulk-like C60 islands, which are supported on the insulating NaCl(001) surface. We exemplify this by controlled charge-manipulation experiments conducted in ultrahigh vacuum by noncontact AFM (nc-AFM), electrostatic force microscopy (EFM) and Kelvin probe force microscopy (KPFM). KPFM shows a homogeneous contrast at the islands, which is a signature for an equal distribution of the electrons in the T1u band. The charge dissipates during half a day due to an interaction of the charged C60 islands with defects in the near surface region of NaCl. Our results open the perspective in photo-voltaics to study charge attachment, stability and charge exchange with the environment of any C60 bulk-like system. Electronic supplementary information (ESI) available. See DOI: 10.1039/C5NR04541J

  12. O--H charge exchange in cold, dense, hydrogen plasmas

    International Nuclear Information System (INIS)

    Cohen, S.A.; Dylla, H.F.

    1977-05-01

    It is pointed out that the accidentally resonant charge exchange reaction, O + + H 0 reverse arrows O 0 + H + , is an important mechanism for causing the loss of singly charged oxygen ions from oxygen contaminated hydrogen plasmas. Results of a Monte Carlo simulation are presented which show that the fraction of oxygen lost because of charge exchange exceeds 1 / 3 when the parameters n/sub e/ approx. 10 13 cm -3 , n/sub H//sup o/ approx. 10 11 cm -3 and T/sub e/ approx. 3 eV are attained

  13. Charged Galileon black holes

    International Nuclear Information System (INIS)

    Babichev, Eugeny; Charmousis, Christos; Hassaine, Mokhtar

    2015-01-01

    We consider an Abelian gauge field coupled to a particular truncation of Horndeski theory. The Galileon field has translation symmetry and couples non minimally both to the metric and the gauge field. When the gauge-scalar coupling is zero the gauge field reduces to a standard Maxwell field. By taking into account the symmetries of the action, we construct charged black hole solutions. Allowing the scalar field to softly break symmetries of spacetime we construct black holes where the scalar field is regular on the black hole event horizon. Some of these solutions can be interpreted as the equivalent of Reissner-Nordstrom black holes of scalar tensor theories with a non trivial scalar field. A self tuning black hole solution found previously is extended to the presence of dyonic charge without affecting whatsoever the self tuning of a large positive cosmological constant. Finally, for a general shift invariant scalar tensor theory we demonstrate that the scalar field Ansatz and method we employ are mathematically compatible with the field equations. This opens up the possibility for novel searches of hairy black holes in a far more general setting of Horndeski theory

  14. Charged boson stars

    Science.gov (United States)

    Pugliese, Daniela; Quevedo, Hernando; Rueda H., Jorge A.; Ruffini, Remo

    2013-07-01

    We study time-independent, spherically symmetric, self-gravitating systems minimally coupled to a scalar field with U(1) gauge symmetry: charged boson stars. We find numerical solutions to the Einstein-Maxwell equations coupled to the relativistic Klein-Gordon equation. It is shown that bound stable configurations exist only for values of the coupling constant less than or equal to a certain critical value. The metric coefficients and the relevant physical quantities, such as the total mass and charge, turn out to be, in general, bound functions of the radial coordinate, reaching their maximum values at a critical value of the scalar field at the origin. We discuss the stability problem from both the quantitative and qualitative point of view. We take into account the electromagnetic contribution to the total mass and investigate the stability issue considering the binding energy per particle. We verify the existence of configurations with positive binding energy in which objects that are apparently bound can be unstable against small perturbations, in full analogy with the effect observed in the mass-radius relation of neutron stars.

  15. Battery charging control methods, electric vehicle charging methods, battery charging apparatuses and rechargeable battery systems

    Science.gov (United States)

    Tuffner, Francis K [Richland, WA; Kintner-Meyer, Michael C. W. [Richland, WA; Hammerstrom, Donald J [West Richland, WA; Pratt, Richard M [Richland, WA

    2012-05-22

    Battery charging control methods, electric vehicle charging methods, battery charging apparatuses and rechargeable battery systems. According to one aspect, a battery charging control method includes accessing information regarding a presence of at least one of a surplus and a deficiency of electrical energy upon an electrical power distribution system at a plurality of different moments in time, and using the information, controlling an adjustment of an amount of the electrical energy provided from the electrical power distribution system to a rechargeable battery to charge the rechargeable battery.

  16. Real-time monitoring and manipulation of single bio-molecules in free solution

    Energy Technology Data Exchange (ETDEWEB)

    Li, Hung-Wing [Iowa State Univ., Ames, IA (United States)

    2005-01-01

    The observation and manipulation of single biomolecules allow their dynamic behaviors to be studied to provide insight into molecular genetics, biochip assembly, biosensor design, DNA biophysics. In a PDMS/glass microchannel, a nonuniform electroosmotic flow (EOF) was created. By using a scanning confocal fluorescence microscope and total internal-reflection fluorescence microscope (TIRFM), we demonstrated that negatively charged DNA molecules were focused by the nonuniform EOF into a thin layer at the glass surface. This phenomenon was applied to selectively detect target DNA molecules without requiring the separation of excessive probes and can be applied continuously to achieve high throughput. A variable-angle-TIRFM was constructed for imaging single DNA molecule dynamics at a solid/liquid interface. Implications we have are that the measured intensities cannot be used directly to determine the distances of molecules from the surface and the experimental counting results depict the distance-dependent dynamics of molecules near the surface; Molecules at low ionic strengths experience electrostatic repulsion at distances much further away from the surface than the calculated thickness of the electrical double layer. {delta}-DNA was employed as a nanoprobe for different functionalized surfaces to elucidate adsorption in chromatography. The 12-base unpaired ends of this DNA provide exposed purine and pyrimidine groups for adsorption. Patterns of self-assembled monolayers (SAMs) and patterns of metal oxides are generated. By recording the real-time dynamic motion of DNA molecules at the SAMs/aqueous interface, the various parameters governing the retention of an analyte during chromatographic separation can be studied. Even subtle differences among adsorptive forces can be revealed. Dynamic conformational changes of the prosthetic group, flavin adenine dinucleotide (FAD), in flavoprotein NADH peroxidase, in thioredoxin reductase, and in free solution were monitored

  17. Non-linear quantitative structure-activity relationship for adenine derivatives as competitive inhibitors of adenosine deaminase

    International Nuclear Information System (INIS)

    Sadat Hayatshahi, Sayyed Hamed; Abdolmaleki, Parviz; Safarian, Shahrokh; Khajeh, Khosro

    2005-01-01

    Logistic regression and artificial neural networks have been developed as two non-linear models to establish quantitative structure-activity relationships between structural descriptors and biochemical activity of adenosine based competitive inhibitors, toward adenosine deaminase. The training set included 24 compounds with known k i values. The models were trained to solve two-class problems. Unlike the previous work in which multiple linear regression was used, the highest of positive charge on the molecules was recognized to be in close relation with their inhibition activity, while the electric charge on atom N1 of adenosine was found to be a poor descriptor. Consequently, the previously developed equation was improved and the newly formed one could predict the class of 91.66% of compounds correctly. Also optimized 2-3-1 and 3-4-1 neural networks could increase this rate to 95.83%

  18. Isosteric analogues of nicotinamide adenine dinucleotide derived from furanfurin, thiophenfurin, and selenophenfurin as mammalian inosine monophosphate dehydrogenase (type I and II) inhibitors.

    Science.gov (United States)

    Franchetti, P; Cappellacci, L; Perlini, P; Jayaram, H N; Butler, A; Schneider, B P; Collart, F R; Huberman, E; Grifantini, M

    1998-05-07

    Dinucleotides TFAD (6), FFAD (7), and SFAD (8), isosteric NAD analogues derived, respectively, from C-nucleosides 5-beta-d-ribofuranosylthiophene-3-carboxamide (thiophenfurin, 1), 5-beta-d-ribofuranosylfuran-3-carboxamide (furanfurin, 2), and 5-beta-d-ribofuranosylselenophene-3-carboxamide (selenophenfurin, 5), were synthesized as human inosine monophosphate dehydrogenase (IMPDH) type I and II inhibitors. The synthesis was carried out by imidazole-catalyzed coupling of the 5'-monophosphate of 1, 2, and 5 with AMP. These dinucleotides, which are also analogues of thiazole-4-carboxamide adenine dinucleotide (TAD) and selenazole-4-carboxamide adenine dinucleotide (SAD), the active metabolites of the oncolytic C-nucleosides 2-beta-D-ribofuranosylthiazole-4-carboxamide (tiazofurin) and 2-beta-D-ribofuranosylselenazole-4-carboxamide (selenazofurin), were evaluated for their inhibitory potency against recombinant human IMPDH type I and II. The order of inhibitory potency found was SAD > SFAD = TFAD = TAD > FFAD for both enzyme isoforms. No significant difference was found in inhibition of IMPDH type I and II.

  19. Synthesis and antiviral properties of novel 7-heterocyclic substituted 7-deaza-adenine nucleoside inhibitors of Hepatitis C NS5B polymerase.

    Science.gov (United States)

    Di Francesco, M Emilia; Avolio, Salvatore; Pompei, Marco; Pesci, Silvia; Monteagudo, Edith; Pucci, Vincenzo; Giuliano, Claudio; Fiore, Fabrizio; Rowley, Michael; Summa, Vincenzo

    2012-08-01

    Previous investigations in our laboratories resulted in the discovery of a novel series of potent nucleoside inhibitors of Hepatitis C virus (HCV) NS5B polymerase bearing tetracyclic 7-substituted 7-deaza-adenine nucleobases. The planarity of such modified systems was suggested to play a role in the high inhibitory potency observed. This paper describes how we envisaged to maintain the desired planarity of the modified nucleobase by means of an intra-molecular H-bond, engaging a H-bond donor atom on an appropriately substituted 7-heterocyclic residue with the adjacent amino group of the nucleobase. The success of this strategy is reflected by the identification of several novel potent nucleoside inhibitors of HCV NS5B bearing a 7-heterocyclic substituted 7-deaza-adenine nucleobase. Amongst these, the 1,2,4-oxadiazole analog 11 showed high antiviral potency against HCV replication in replicon cells and efficient conversion to the corresponding NTP in vivo, with high and sustained levels of NTP measured in rat liver following intravenous and oral administration. Copyright © 2012 Elsevier Ltd. All rights reserved.

  20. Pattern of OH radical reaction with adenine and its nucleosides and nucleotides. Characterization of two types of isomeric OH adduct and their unimolecular transformation reactions

    International Nuclear Information System (INIS)

    Vieira, A.J.S.C.; Steenken, S.

    1990-01-01

    The sm-bullet OH radical reacts in aqueous solution with adenine, 9-methyladenine, adenosine and its 3'- and 5'-mono- and 3',5'-diphosphates, and with the corresponding 2'-deoxyadenosines by addition to C4 and to C8 of the purine system. The resulting hydroxycyclohexa- or penta(aza)dienyl-type radicals A4OH sm-bullet (formed by sm-bullet OH addition at C4) and A8OH sm-bullet (by addition at C8) undergo a dehydration and a ring-opening reaction, respectively, for which the activation parameters and pH dependencies have been determined. Dehydration of A4OH sm-bullet , which yields an oxidizing N 6 -centered neutral radical, is inhibited by H + , whereas the ring opening of A8OH sm-bullet is accelerated by H + (and also by OH - ). Product analysis data on adenine concerning the effect of additives on the yield of its depletion and of formation of 8-hydroxyadenine indicate that the N 6 -centered radical is repaired by reduction by radicals derived from A8OH sm-bullet