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Sample records for molecules including nuclear

  1. High-order harmonic generation from polyatomic molecules including nuclear motion and a nuclear modes analysis

    SciTech Connect

    Madsen, C. B.; Abu-samha, M.; Madsen, L. B.

    2010-04-15

    We present a generic approach for treating the effect of nuclear motion in high-order harmonic generation from polyatomic molecules. Our procedure relies on a separation of nuclear and electron dynamics where we account for the electronic part using the Lewenstein model and nuclear motion enters as a nuclear correlation function. We express the nuclear correlation function in terms of Franck-Condon factors, which allows us to decompose nuclear motion into modes and identify the modes that are dominant in the high-order harmonic generation process. We show results for the isotopes CH{sub 4} and CD{sub 4} and thereby provide direct theoretical support for a recent experiment [S. Baker et al., Science 312, 424 (2006)] that uses high-order harmonic generation to probe the ultrafast structural nuclear rearrangement of ionized methane.

  2. Dynamical Green's function and an exact optical potential for electron-molecule scattering including nuclear dynamics

    NASA Astrophysics Data System (ADS)

    Brand, Joachim; Cederbaum, Lorenz S.; Meyer, Hans-Dieter

    1999-10-01

    We derive a rigorous optical potential for electron-molecule scattering including the effects of nuclear dynamics by extending the common many-body Green's function approach to optical potentials beyond the fixed-nuclei limit for molecular targets. Our formalism treats the projectile electron and the nuclear motion of the target molecule on the same footing whereby the dynamical optical potential rigorously accounts for the complex many-body nature of the scattering target. One central result of the present work is that the common fixed-nuclei optical potential is a valid adiabatic approximation to the dynamical optical potential even when projectile and nuclear motion are (nonadiabatically) coupled as long as the scattering energy is well below the electronic excitation thresholds of the target. For extremely low projectile velocities, however, when the cross sections are most sensitive to the scattering potential, we expect the influences of the nuclear dynamics on the optical potential to become relevant. For these cases, a systematic way to improve the adiabatic approximation to the dynamical optical potential is presented that yields nonlocal operators with respect to the nuclear coordinates.

  3. Nuclear Chemistry: Include It in Your Curriculum.

    ERIC Educational Resources Information Center

    Atwood, Charles H.; Sheline, R. K.

    1989-01-01

    Some of the topics that might be included in a nuclear chemistry section are explored. Offers radioactivity, closed shells in nuclei, energy of nuclear processes, nuclear reactions, and fission and fusion as topics of interest. Provided are ideas and examples for each. (MVL)

  4. Nuclear Chemistry: Include It in Your Curriculum.

    ERIC Educational Resources Information Center

    Atwood, Charles H.; Sheline, R. K.

    1989-01-01

    Some of the topics that might be included in a nuclear chemistry section are explored. Offers radioactivity, closed shells in nuclei, energy of nuclear processes, nuclear reactions, and fission and fusion as topics of interest. Provided are ideas and examples for each. (MVL)

  5. Nuclear reactor shield including magnesium oxide

    DOEpatents

    Rouse, Carl A.; Simnad, Massoud T.

    1981-01-01

    An improvement in nuclear reactor shielding of a type used in reactor applications involving significant amounts of fast neutron flux, the reactor shielding including means providing structural support, neutron moderator material, neutron absorber material and other components as described below, wherein at least a portion of the neutron moderator material is magnesium in the form of magnesium oxide either alone or in combination with other moderator materials such as graphite and iron.

  6. Single-Molecule Imaging of Nuclear Transport

    PubMed Central

    Goryaynov, Alexander; Sarma, Ashapurna; Ma, Jiong; Yang, Weidong

    2010-01-01

    The utility of single molecule fluorescence microscopy approaches has been proven to be of a great avail in understanding biological reactions over the last decade. The investigation of molecular interactions with high temporal and spatial resolutions deep within cells has remained challenging due to the inherently weak signals arising from individual molecules. Recent works by Yang et al. demonstrated that narrow-field epifluorescence microscopy allows visualization of nucleocytoplasmic transport at the single molecule level. By the single molecule approach, important kinetics, such as nuclear transport time and efficiency, for signal-dependent and independent cargo molecules have been obtained. Here we described a protocol for the methodological approach with an improved spatiotemporal resolution of 0.4 ms and 12 nm. The improved resolution enabled us to capture transient active transport and passive diffusion events through the nuclear pore complexes (NPC) in semi-intact cells. We expect this method to be used in elucidating other binding and trafficking events within cells. PMID:20548283

  7. Aerosol simulation including chemical and nuclear reactions

    SciTech Connect

    Marwil, E.S.; Lemmon, E.C.

    1985-01-01

    The numerical simulation of aerosol transport, including the effects of chemical and nuclear reactions presents a challenging dynamic accounting problem. Particles of different sizes agglomerate and settle out due to various mechanisms, such as diffusion, diffusiophoresis, thermophoresis, gravitational settling, turbulent acceleration, and centrifugal acceleration. Particles also change size, due to the condensation and evaporation of materials on the particle. Heterogeneous chemical reactions occur at the interface between a particle and the suspending medium, or a surface and the gas in the aerosol. Homogeneous chemical reactions occur within the aersol suspending medium, within a particle, and on a surface. These reactions may include a phase change. Nuclear reactions occur in all locations. These spontaneous transmutations from one element form to another occur at greatly varying rates and may result in phase or chemical changes which complicate the accounting process. This paper presents an approach for inclusion of these effects on the transport of aerosols. The accounting system is very complex and results in a large set of stiff ordinary differential equations (ODEs). The techniques for numerical solution of these ODEs require special attention to achieve their solution in an efficient and affordable manner. 4 refs.

  8. Nuclear Magnetic Shieldings of Stacked Aromatic and Antiaromatic Molecules.

    PubMed

    Sundholm, Dage; Rauhalahti, Markus; Özcan, Nergiz; Mera-Adasme, Raúl; Kussmann, Jörg; Luenser, Arne; Ochsenfeld, Christian

    2017-04-04

    Nuclear magnetic shieldings have been calculated at the density functional theory (DFT) level for stacks of benzene, hexadehydro[12]annulene, dodecadehydro[18]annulene, and hexabenzocoronene. The magnetic shieldings due to the ring currents in the adjacent molecules have been estimated by calculating nucleus independent molecular shieldings for the monomer in the atomic positions of neighbor molecules. The calculations show that the independent shielding model works reasonably well for the (1)H NMR shieldings of benzene and hexadehydro[12]annulene, whereas for the larger molecules and for the (13)C NMR shieldings the interaction between the molecules leads to shielding effects that are at least of the same size as the ring current contributions from the adjacent molecules. A better agreement is obtained when the nearest neighbors are also considered at full quantum mechanical (QM) level. The calculations suggest that the nearest solvent molecules must be included in the quantum mechanical system, at least when estimating solvent shifts at the molecular mechanics (MM) level. Current density calculations show that the stacking does not significantly affect the ring current strengths of the individual molecules, whereas the shape of the ring current for a single molecule differs from that of the stacked molecules.

  9. Attosecond electronic and nuclear quantum photodynamics of the ozone molecule

    SciTech Connect

    Halász, G. J.; Perveaux, A.; Lasorne, B.; Gatti, F.; Robb, M. A.; Vibók, Á.

    2013-11-13

    Coupled electron-nuclear dynamics simulations are investigated for the ozone molecule on the attosecond time scale. The initial wavepacket is pumped as a coherent superposition of two or three electronic states.

  10. Nuclear spin-induced Cotton-Mouton effect in molecules.

    PubMed

    Fu, Li-juan; Vaara, Juha

    2013-05-28

    In nuclear magneto-optic spectroscopy, effects of nuclear magnetization are detected in light passing through a sample containing spin-polarized nuclei. An optical analogue of nuclear magnetic resonance (NMR) chemical shift has been predicted and observed in the nuclear spin optical rotation of linearly polarized light propagating parallel to the nuclear magnetization. A recently proposed magneto-optic analogue of the NMR spin-spin coupling, the nuclear spin-induced Cotton-Mouton (NSCM) effect entails an ellipticity induced to linearly polarized light when passing through a medium with the nuclear spins polarized in a direction perpendicular to the light beam. Here we present a first-principles electronic structure formulation of NSCM in terms of response theory as well as ab initio and density-functional theory calculations for small molecules. The roles of basis set (we use completeness-optimized sets), electron correlation, and relativistic effects are discussed. It is found that the explicitly temperature-dependent contribution to NSCM, arising from the partial orientation of the molecules due to the nuclear magnetization, typically dominates the effect. This part of NSCM is proportional to the tensor product of molecular polarizability and the NMR direct dipolar coupling tensor. Hence, NSCM provides a means of investigating the dipolar coupling and, thus, molecular structure in a formally isotropic medium. Overall ellipticities of the order of magnitude of 10(-8)...10(-7) rad/(M cm) are predicted for fully polarized nuclei. These should be detectable with modern instrumentation in the Voigt setup.

  11. Schematic model for nuclear molecules as doorway states for fusion

    SciTech Connect

    Hess, P.O. ); Pereyra, P. )

    1990-10-01

    An elementary simple model for nuclear molecules is used to describe the molecular spectrum of the {sup 12}C-{sup 12}C system. Through that model the molecular potential is determined. Without further parameters the total fusion cross section around and below the barrier is calculated with good results indicating a correlation between the molecular spectrum and fusion. It is concluded that nuclear molecules may possibly be the doorway states for fusion. The simplicity of the model used allows a deeper schematic insight of the mechanism of fusion.

  12. Observation of rotating nuclear molecules and determination of their lifetimes

    NASA Astrophysics Data System (ADS)

    Comas, V.; Heinz, S.; Hofmann, S.; Ackermann, D.; Heredia, J.; Heßberger, F. P.; Khuyagbaatar, J.; Kindler, B.; Lommel, B.; Mann, R.

    2012-12-01

    Long-living rotating nuclear molecules (or "dinuclear systems") have been observed at the velocity filter SHIP at GSI in reactions of 64Ni + 207Pb at Coulomb barrier energies. The rotation was directly revealed by the velocity spectra of deep inelastic target-like transfer products which are formed during the lifetime of the nuclear molecule and emitted after its breakup. The corresponding rotation angles were about 180 degree pointing to long nuclear interaction times or lifetimes of the system, respectively. We deduced the lifetimes from the lines in the velocity spectra originating from two different rotation angles. Further, the unambiguous correlation of a certain transfer product with its individual velocity spectrum allowed us to study the lifetimes as a function of the number of transferred protons.

  13. Nuclear spin-induced Cotton-Mouton effect in molecules

    NASA Astrophysics Data System (ADS)

    Fu, Li-juan; Vaara, Juha

    2013-05-01

    In nuclear magneto-optic spectroscopy, effects of nuclear magnetization are detected in light passing through a sample containing spin-polarized nuclei. An optical analogue of nuclear magnetic resonance (NMR) chemical shift has been predicted and observed in the nuclear spin optical rotation of linearly polarized light propagating parallel to the nuclear magnetization. A recently proposed magneto-optic analogue of the NMR spin-spin coupling, the nuclear spin-induced Cotton-Mouton (NSCM) effect entails an ellipticity induced to linearly polarized light when passing through a medium with the nuclear spins polarized in a direction perpendicular to the light beam. Here we present a first-principles electronic structure formulation of NSCM in terms of response theory as well as ab initio and density-functional theory calculations for small molecules. The roles of basis set (we use completeness-optimized sets), electron correlation, and relativistic effects are discussed. It is found that the explicitly temperature-dependent contribution to NSCM, arising from the partial orientation of the molecules due to the nuclear magnetization, typically dominates the effect. This part of NSCM is proportional to the tensor product of molecular polarizability and the NMR direct dipolar coupling tensor. Hence, NSCM provides a means of investigating the dipolar coupling and, thus, molecular structure in a formally isotropic medium. Overall ellipticities of the order of magnitude of 10-8…10-7 rad/(M cm) are predicted for fully polarized nuclei. These should be detectable with modern instrumentation in the Voigt setup.

  14. Diffractive Imaging of Coherent Nuclear Motion in Isolated Molecules

    NASA Astrophysics Data System (ADS)

    Yang, Jie; Guehr, Markus; Shen, Xiaozhe; Li, Renkai; Vecchione, Theodore; Coffee, Ryan; Corbett, Jeff; Fry, Alan; Hartmann, Nick; Hast, Carsten; Hegazy, Kareem; Jobe, Keith; Makasyuk, Igor; Robinson, Joseph; Robinson, Matthew S.; Vetter, Sharon; Weathersby, Stephen; Yoneda, Charles; Wang, Xijie; Centurion, Martin

    2016-10-01

    Observing the motion of the nuclear wave packets during a molecular reaction, in both space and time, is crucial for understanding and controlling the outcome of photoinduced chemical reactions. We have imaged the motion of a vibrational wave packet in isolated iodine molecules using ultrafast electron diffraction with relativistic electrons. The time-varying interatomic distance was measured with a precision 0.07 Å and temporal resolution of 230 fs full width at half maximum. The method is not only sensitive to the position but also the shape of the nuclear wave packet.

  15. Diffractive imaging of coherent nuclear motion in isolated molecules

    DOE PAGES

    Yang, Jie; Guehr, Markus; Shen, Xiaozhe; ...

    2016-10-03

    Observing the motion of the nuclear wave packets during a molecular reaction, in both space and time, is crucial for understanding and controlling the outcome of photoinduced chemical reactions. We have imaged the motion of a vibrational wave packet in isolated iodine molecules using ultrafast electron diffraction with relativistic electrons. The time-varying interatomic distance was measured with a precision 0.07 Å and temporal resolution of 230 fs full width at half maximum. Lastly, the method is not only sensitive to the position but also the shape of the nuclear wave packet.

  16. Diffractive imaging of coherent nuclear motion in isolated molecules

    SciTech Connect

    Yang, Jie; Guehr, Markus; Shen, Xiaozhe; Li, Renkai; Vecchione, Theodore; Coffee, Ryan; Corbett, Jeff; Fry, Alan; Hartmann, Nick; Hast, Carsten; Hegazy, Kareem; Jobe, Keith; Makasyuk, Igor; Robinson, Joseph; Robinson, Matthew S.; Vetter, Sharon; Weathersby, Stephen; Yoneda, Charles; Wang, Xijie; Centurion, Martin

    2016-10-03

    Observing the motion of the nuclear wave packets during a molecular reaction, in both space and time, is crucial for understanding and controlling the outcome of photoinduced chemical reactions. We have imaged the motion of a vibrational wave packet in isolated iodine molecules using ultrafast electron diffraction with relativistic electrons. The time-varying interatomic distance was measured with a precision 0.07 Å and temporal resolution of 230 fs full width at half maximum. Lastly, the method is not only sensitive to the position but also the shape of the nuclear wave packet.

  17. Diffractive Imaging of Coherent Nuclear Motion in Isolated Molecules

    SciTech Connect

    Yang, Jie; Guehr, Markus; Shen, Xiaozhe; Li, Renkai; Vecchione, Theodore; Coffee, Ryan; Corbett, Jeff; Fry, Alan; Hartmann, Nick; Hast, Carsten; Hegazy, Kareem; Jobe, Keith; Makasyuk, Igor; Robinson, Joseph; Robinson, Matthew S.; Vetter, Sharon; Weathersby, Stephen; Yoneda, Charles; Wang, Xijie; Centurion, Martin

    2016-10-03

    Observing the motion of the nuclear wave packets during a molecular reaction, in both space and time, is crucial for understanding and controlling the outcome of photoinduced chemical reactions. We have imaged the motion of a vibrational wave packet in isolated iodine molecules using ultrafast electron diffraction with relativistic electrons. The time-varying interatomic distance was measured with a precision 0.07 Å and temporal resolution of 230 fs full width at half maximum. The method is not only sensitive to the position but also the shape of the nuclear wave packet.

  18. Nuclear Fusion Rate Study of a Muonic Molecule via Nuclear Threshold Resonances

    NASA Astrophysics Data System (ADS)

    Faghihi, F.; Eskandari, M. R.

    This work follows our previous calculations of the ground state binding energy, size, and the effective nuclear charge of the muonic T3 molecule, using the Born-Oppenheimer adiabatic approximation. In our past articles, we showed that the system possesses two minimum positions, the first one at the muonic distance and the second at the atomic distance. Also, the symmetric planner vibrational model assumed between the two minima and the approximated potential were calculated. Following from the previous studies, we now calculate the fusion rate of the T3 muonic molecule according to the overlap integral of the resonance nuclear compound nucleus and the molecular wave functions.

  19. Electron flux in molecules induced by nuclear motion

    NASA Astrophysics Data System (ADS)

    Okuyama, Michihiro; Takatsuka, Kazuo

    2009-07-01

    As a general tool for analysis of chemical reactions from the view point of electron wavepacket dynamics, electron flux within a molecule is numerically realized in terms of physically time-dependent electronic wavefunctions given by the semiclassical Ehrenfest theory. These wavefunctions are synchronized with real time motion of molecular nuclei through the nuclear kinematic coupling (nonadiabatic elements). Since the standard quantum flux gives only a null field for a real-valued electronic eigenfunction, we extend the definition of flux such that the essential information of dynamical flow of electrons can be retrieved even from adiabatic electronic wavefunctions calculated in the scheme of the so-called ab initio molecular dynamics.

  20. Nuclear dynamics during the resonant Auger decay of water molecules.

    PubMed

    Eroms, Matthis; Vendrell, Oriol; Jungen, Martin; Meyer, Hans-Dieter; Cederbaum, Lorenz S

    2009-04-21

    The resonant Auger decay of water molecules is investigated. Here, the excitation process, the motion of the nuclei, and the decay of the resonantly excited state take place on the same (femtosecond) time scale. Therefore, a multistep picture is not suitable. Instead, the nuclear wave packet at each instant of time is a result of several competing and interfering contributions. The resonant Auger decay of water is simulated and its dynamics is studied in detail. An analysis of the final vibrational distribution is given. The multiconfiguration time-dependent Hartree method is used to study the intricate multidimensional dynamics. The potential energy surfaces have been calculated using a multireference configuration interaction method.

  1. Nuclear Magnetic Resonance Coupling Constants and Electronic Structure in Molecules.

    ERIC Educational Resources Information Center

    Venanzi, Thomas J.

    1982-01-01

    Theory of nuclear magnetic resonance spin-spin coupling constants and nature of the three types of coupling mechanisms contributing to the overall spin-spin coupling constant are reviewed, including carbon-carbon coupling (neither containing a lone pair of electrons) and carbon-nitrogen coupling (one containing a lone pair of electrons).…

  2. Nuclear Magnetic Resonance Coupling Constants and Electronic Structure in Molecules.

    ERIC Educational Resources Information Center

    Venanzi, Thomas J.

    1982-01-01

    Theory of nuclear magnetic resonance spin-spin coupling constants and nature of the three types of coupling mechanisms contributing to the overall spin-spin coupling constant are reviewed, including carbon-carbon coupling (neither containing a lone pair of electrons) and carbon-nitrogen coupling (one containing a lone pair of electrons).…

  3. Nuclear magnetic resonance of laser-polarized noble gases in molecules, materials and organisms

    SciTech Connect

    Goodson, Boyd McLean

    1999-12-01

    Conventional nuclear magnetic resonance (NMR) spectroscopy and magnetic resonance imaging (MRI) are fundamentally challenged by the insensitivity that stems from the ordinarily low spin polarization achievable in even the strongest NMR magnets. However, by transferring angular momentum from laser light to electronic and nuclear spins, optical pumping methods can increase the nuclear spin polarization of noble gases by several orders of magnitude, thereby greatly enhancing their NMR sensitivity. This dissertation is primarily concerned with the principles and practice of optically pumped nuclear magnetic resonance (OPNMR). The enormous sensitivity enhancement afforded by optical pumping noble gases can be exploited to permit a variety of novel NMR experiments across many disciplines. Many such experiments are reviewed, including the void-space imaging of organisms and materials, NMR and MRI of living tissues, probing structure and dynamics of molecules in solution and on surfaces, and zero-field NMR and MRI.

  4. Nuclear data evaluation methodology including estimates of covariances

    NASA Astrophysics Data System (ADS)

    Capote, R.; Smith, D. L.; Trkov, A.

    2010-10-01

    Evaluated nuclear data rather than raw experimental and theoretical information are employed in nuclear applications such as the design of nuclear energy systems. Therefore, the process by which such information is produced and ultimately used is of critical interest to the nuclear science community. This paper provides an overview of various contemporary methods employed to generate evaluated cross sections and related physical quantities such as particle emission angular distributions and energy spectra. The emphasis here is on data associated with neutron induced reaction processes, with consideration of the uncertainties in these data, and on the more recent evaluation methods, e.g., those that are based on stochastic (Monte Carlo) techniques. There is no unique way to perform such evaluations, nor are nuclear data evaluators united in their opinions as to which methods are superior to the others in various circumstances. In some cases it is not critical which approaches are used as long as there is consistency and proper use is made of the available physical information. However, in other instances there are definite advantages to using particular methods as opposed to other options. Some of these distinctions are discussed in this paper and suggestions are offered regarding fruitful areas for future research in the development of evaluation methodology.

  5. Electronic and nuclear flux densities in the H2 molecule

    NASA Astrophysics Data System (ADS)

    Hermann, G.; Paulus, B.; Pérez-Torres, J. F.; Pohl, V.

    2014-05-01

    We present a theoretical study of the electronic and nuclear flux densities of a vibrating H2 molecule after an electronic excitation by a short femtosecond laser pulse. The final state, a coherent superposition of the electronic ground state X1Σg+ and the electronic excited state B1Σu+, evolves freely and permits the partition of the electronic flux density into two competing fluxes: the adiabatic and the transition flux density. The nature of the two fluxes allows us to identify two alternating dynamics of the electronic motion, occurring on the attosecond and the femtosecond time scales. In contradistinction to the adiabatic electronic flux density, the transition electronic flux density shows a dependence on the carrier-envelope phase of the laser field, encoding information of the interaction of the electrons with the electric field. Furthermore, the nuclear flux density displays multiple reversals, a quantum effect recently discovered by Manz et al. [J. Manz, J. F. Pérez-Torres, and Y. Yang, Phys. Rev. Lett. 111, 153004 (2013), 10.1103/PhysRevLett.111.153004], calling for investigation of the electronic flux density.

  6. Novel nuclear magnetic resonance techniques for studying biological molecules

    SciTech Connect

    Laws, David Douglas

    2000-06-01

    Over the fifty-five year history of Nuclear Magnetic Resonance (NMR), considerable progress has been made in the development of techniques for studying the structure, function, and dynamics of biological molecules. The majority of this research has involved the development of multi-dimensional NMR experiments for studying molecules in solution, although in recent years a number of groups have begun to explore NMR methods for studying biological systems in the solid-state. Despite this new effort, a need still exists for the development of techniques that improve sensitivity, maximize information, and take advantage of all the NMR interactions available in biological molecules. In this dissertation, a variety of novel NMR techniques for studying biomolecules are discussed. A method for determining backbone (Φ/Ψ) dihedral angles by comparing experimentally determined 13Ca, chemical-shift anisotropies with theoretical calculations is presented, along with a brief description of the theory behind chemical-shift computation in proteins and peptides. The utility of the Spin-Polarization Induced Nuclear Overhauser Effect (SPINOE) to selectively enhance NMR signals in solution is examined in a variety of systems, as are methods for extracting structural information from cross-relaxation rates that can be measured in SPINOE experiments. Techniques for the production of supercritical and liquid laser-polarized xenon are discussed, as well as the prospects for using optically pumped xenon as a polarizing solvent. In addition, a detailed study of the structure of PrP 89-143 is presented. PrP 89-143 is a 54 residue fragment of the prion proteins which, upon mutation and aggregation, can induce prion diseases in transgenic mice. Whereas the structure of the wild-type PrP 89-143 is a generally unstructured mixture of α-helical and β-sheet conformers in the solid state, the aggregates formed from the PrP 89-143 mutants appear to be mostly β-sheet.

  7. Zirconium-based alloys, nuclear fuel rods and nuclear reactors including such alloys, and related methods

    DOEpatents

    Mariani, Robert Dominick

    2014-09-09

    Zirconium-based metal alloy compositions comprise zirconium, a first additive in which the permeability of hydrogen decreases with increasing temperatures at least over a temperature range extending from 350.degree. C. to 750.degree. C., and a second additive having a solubility in zirconium over the temperature range extending from 350.degree. C. to 750.degree. C. At least one of a solubility of the first additive in the second additive over the temperature range extending from 350.degree. C. to 750.degree. C. and a solubility of the second additive in the first additive over the temperature range extending from 350.degree. C. to 750.degree. C. is higher than the solubility of the second additive in zirconium over the temperature range extending from 350.degree. C. to 750.degree. C. Nuclear fuel rods include a cladding material comprising such metal alloy compositions, and nuclear reactors include such fuel rods. Methods are used to fabricate such zirconium-based metal alloy compositions.

  8. Maria Goeppert Mayer: atoms, molecules and nuclear shells

    SciTech Connect

    Johnson, K.E.

    1986-09-01

    The mathematical physicist's early work in atomic and molecular physics, and her unfamiliarity with the ''fashions'' in nuclear physics, gave her the ideal preparation for solving the puzzle of the nuclear ''magic numbers.''

  9. Incorporating nuclear vibrational energies into the "atom in molecules" analysis: An analytical study

    NASA Astrophysics Data System (ADS)

    Gharabaghi, Masumeh; Shahbazian, Shant

    2017-04-01

    The quantum theory of atoms in molecules (QTAIM) is based on the clamped nucleus paradigm and solely working with the electronic wavefunctions, so does not include nuclear vibrations in the AIM analysis. On the other hand, the recently extended version of the QTAIM, called the multi-component QTAIM (MC-QTAIM), incorporates both electrons and quantum nuclei, i.e., those nuclei treated as quantum waves instead of clamped point charges, into the AIM analysis using non-adiabatic wavefunctions. Thus, the MC-QTAIM is the natural framework to incorporate the role of nuclear vibrations into the AIM analysis. In this study, within the context of the MC-QTAIM, the formalism of including nuclear vibrational energy in the atomic basin energy is developed in detail and its contribution is derived analytically using the recently proposed non-adiabatic Hartree product nuclear wavefunction. It is demonstrated that within the context of this wavefunction, the quantum nuclei may be conceived pseudo-adiabatically as quantum oscillators and both isotropic harmonic and anisotropic anharmonic oscillator models are used to compute the zero-point nuclear vibrational energy contribution to the basin energies explicitly. Inspired by the results gained within the context of the MC-QTAIM analysis, a heuristic approach is proposed within the context of the QTAIM to include nuclear vibrational energy in the basin energy from the vibrational wavefunction derived adiabatically. The explicit calculation of the basin contribution of the zero-point vibrational energy using the uncoupled harmonic oscillator model leads to results consistent with those derived from the MC-QTAIM.

  10. Incorporating nuclear vibrational energies into the "atom in molecules" analysis: An analytical study.

    PubMed

    Gharabaghi, Masumeh; Shahbazian, Shant

    2017-04-21

    The quantum theory of atoms in molecules (QTAIM) is based on the clamped nucleus paradigm and solely working with the electronic wavefunctions, so does not include nuclear vibrations in the AIM analysis. On the other hand, the recently extended version of the QTAIM, called the multi-component QTAIM (MC-QTAIM), incorporates both electrons and quantum nuclei, i.e., those nuclei treated as quantum waves instead of clamped point charges, into the AIM analysis using non-adiabatic wavefunctions. Thus, the MC-QTAIM is the natural framework to incorporate the role of nuclear vibrations into the AIM analysis. In this study, within the context of the MC-QTAIM, the formalism of including nuclear vibrational energy in the atomic basin energy is developed in detail and its contribution is derived analytically using the recently proposed non-adiabatic Hartree product nuclear wavefunction. It is demonstrated that within the context of this wavefunction, the quantum nuclei may be conceived pseudo-adiabatically as quantum oscillators and both isotropic harmonic and anisotropic anharmonic oscillator models are used to compute the zero-point nuclear vibrational energy contribution to the basin energies explicitly. Inspired by the results gained within the context of the MC-QTAIM analysis, a heuristic approach is proposed within the context of the QTAIM to include nuclear vibrational energy in the basin energy from the vibrational wavefunction derived adiabatically. The explicit calculation of the basin contribution of the zero-point vibrational energy using the uncoupled harmonic oscillator model leads to results consistent with those derived from the MC-QTAIM.

  11. Monitoring Nonadiabatic Electron-Nuclear Dynamics in Molecules by Attosecond Streaking of Photoelectrons

    NASA Astrophysics Data System (ADS)

    Kowalewski, Markus; Bennett, Kochise; Rouxel, Jérémy R.; Mukamel, Shaul

    2016-07-01

    Streaking of photoelectrons has long been used for the temporal characterization of attosecond extreme ultraviolet pulses. When the time-resolved photoelectrons originate from a coherent superposition of electronic states, they carry additional phase information, which can be retrieved by the streaking technique. In this contribution we extend the streaking formalism to include coupled electron and nuclear dynamics in molecules as well as initial coherences. We demonstrate how streaked photoelectrons offer a novel tool for monitoring nonadiabatic dynamics as it occurs in the vicinity of conical intersections and avoided crossings. Streaking can provide high time resolution direct signatures of electronic coherences, which affect many primary photochemical and biological events.

  12. Relativistic study of nuclear-anapole-moment effects in diatomic molecules

    NASA Astrophysics Data System (ADS)

    Borschevsky, A.; Iliaš, M.; Dzuba, V. A.; Flambaum, V. V.; Schwerdtfeger, P.

    2013-08-01

    Nuclear-spin-dependent (NSD) parity violating effects are studied for a number of diatomic molecules using relativistic Hartree-Fock and density-functional theory and accounting for core polarization effects. Heavy diatomic molecules are good candidates for the successful measurement of the nuclear anapole moment, which is the dominant NSD parity violation term in heavy elements. Improved results for the molecules studied in our previous publication [Borschevsky , Phys. Rev. APLRAAN1050-294710.1103/PhysRevA.85.052509 85, 052509 (2012)] are presented along with the calculations for a number of other promising candidates for the nuclear anapole measurements.

  13. Correlated electron-nuclear dynamics in above-threshold multiphoton ionization of asymmetric molecule

    PubMed Central

    Wang, Zhuo; Li, Min; Zhou, Yueming; Lan, Pengfei; Lu, Peixiang

    2017-01-01

    The partition of the photon energy into the subsystems of molecules determines many photon-induced chemical and physical dynamics in laser-molecule interactions. The electron-nuclear energy sharing from multiphoton ionization of molecules has been used to uncover the correlated dynamics of the electron and fragments. However, most previous studies focus on symmetric molecules. Here we study the electron-nuclear energy sharing in strong-field photoionization of HeH2+ by solving the one-dimensional time-dependent Schrödinger equation (TDSE). Compared with symmetric molecules, the joint electron-nuclear energy spectrum (JES) of HeH2+ reveals an anomalous energy shift at certain nuclear energies, while it disappears at higher and lower nuclear energies. Through tracing the time evolution of the wavepacket of bound states, we identify that this energy shift originates from the joint effect of the Stark shift, associated with the permanent dipole, and the Autler-Townes effect due to the coupling of the 2pσ and 2sσ states in strong fields. The energy shift in the JES appears at certain nuclear distances only when both Stark effect and Autler-Townes effect play important roles. We further demonstrate that the electron-nuclei energy sharing can be controlled by varying laser intensity for asymmetric molecules, providing alternative approaches to manipulate photochemical reactions for more complex molecules. PMID:28218294

  14. Correlated electron-nuclear dynamics in above-threshold multiphoton ionization of asymmetric molecule.

    PubMed

    Wang, Zhuo; Li, Min; Zhou, Yueming; Lan, Pengfei; Lu, Peixiang

    2017-02-20

    The partition of the photon energy into the subsystems of molecules determines many photon-induced chemical and physical dynamics in laser-molecule interactions. The electron-nuclear energy sharing from multiphoton ionization of molecules has been used to uncover the correlated dynamics of the electron and fragments. However, most previous studies focus on symmetric molecules. Here we study the electron-nuclear energy sharing in strong-field photoionization of HeH(2+) by solving the one-dimensional time-dependent Schrödinger equation (TDSE). Compared with symmetric molecules, the joint electron-nuclear energy spectrum (JES) of HeH(2+) reveals an anomalous energy shift at certain nuclear energies, while it disappears at higher and lower nuclear energies. Through tracing the time evolution of the wavepacket of bound states, we identify that this energy shift originates from the joint effect of the Stark shift, associated with the permanent dipole, and the Autler-Townes effect due to the coupling of the 2pσ and 2sσ states in strong fields. The energy shift in the JES appears at certain nuclear distances only when both Stark effect and Autler-Townes effect play important roles. We further demonstrate that the electron-nuclei energy sharing can be controlled by varying laser intensity for asymmetric molecules, providing alternative approaches to manipulate photochemical reactions for more complex molecules.

  15. Correlated electron-nuclear dynamics in above-threshold multiphoton ionization of asymmetric molecule

    NASA Astrophysics Data System (ADS)

    Wang, Zhuo; Li, Min; Zhou, Yueming; Lan, Pengfei; Lu, Peixiang

    2017-02-01

    The partition of the photon energy into the subsystems of molecules determines many photon-induced chemical and physical dynamics in laser-molecule interactions. The electron-nuclear energy sharing from multiphoton ionization of molecules has been used to uncover the correlated dynamics of the electron and fragments. However, most previous studies focus on symmetric molecules. Here we study the electron-nuclear energy sharing in strong-field photoionization of HeH2+ by solving the one-dimensional time-dependent Schrödinger equation (TDSE). Compared with symmetric molecules, the joint electron-nuclear energy spectrum (JES) of HeH2+ reveals an anomalous energy shift at certain nuclear energies, while it disappears at higher and lower nuclear energies. Through tracing the time evolution of the wavepacket of bound states, we identify that this energy shift originates from the joint effect of the Stark shift, associated with the permanent dipole, and the Autler-Townes effect due to the coupling of the 2pσ and 2sσ states in strong fields. The energy shift in the JES appears at certain nuclear distances only when both Stark effect and Autler-Townes effect play important roles. We further demonstrate that the electron-nuclei energy sharing can be controlled by varying laser intensity for asymmetric molecules, providing alternative approaches to manipulate photochemical reactions for more complex molecules.

  16. Nanocoating of titanium implant surfaces with organic molecules. Polysaccharides including glycosaminoglycans.

    PubMed

    Gurzawska, Katarzyna; Svava, Rikke; Jørgensen, Niklas Rye; Gotfredsen, Klaus

    2012-12-01

    Long-term stability of titanium implants are dependent on a variety of factors. Nanocoating with organic molecules is one of the method used to improve osseointegration. Nanoscale modification of titanium implants affects surface properties, such as hydrophilicity, biochemical bonding capacity and roughness. This influences cell behaviour on the surface such as adhesion, proliferation and differentiation of cells as well as the mineralization of the extracellular matrix at the implant surfaces. The aim of the present systematic review was to describe organic molecules used for surface nanocoating with focus on polysaccharides including glycosaminoglycans, and how these molecules change surface properties, cell reactions and affect on osseointegartion. The included in vitro studies demonstrated increased cell adhesion, proliferation and mineralization of a number of the tested polysaccharide nanocoatings. The included in vivo studies, showed improvement of bone interface reactions measured as increased Bone-to-Implant Contact length and Bone Mineral Density adjacent to the polysaccharide coated surfaces. Based on existing literature, surface modification with polysaccharide and glycosaminoglycans appears to be an effective way to stimulate bone regeneration on bone-implant interface.

  17. Nuclear actin activates human transcription factor genes including the OCT4 gene.

    PubMed

    Yamazaki, Shota; Yamamoto, Koji; Tokunaga, Makio; Sakata-Sogawa, Kumiko; Harata, Masahiko

    2015-01-01

    RNA microarray analyses revealed that nuclear actin activated many human transcription factor genes including OCT4, which is required for gene reprogramming. Oct4 is known to be activated by nuclear actin in Xenopus oocytes. Our findings imply that this process of OCT4 activation is conserved in vertebrates and among cell types and could be used for gene reprogramming of human cells.

  18. Non-nuclear Electron Transport Channels in Hollow Molecules

    SciTech Connect

    Zhao, Jin; Petek, Hrvoje

    2014-08-15

    Electron transport in inorganic semiconductors and metals occurs through delocalized bands formed by overlapping electron orbitals. Strong correlation of electronic wave functions with the ionic cores couples the electron and lattice motions, leading to efficient interaction and scattering that degrades coherent charge transport. By contrast, unoccupied electronic states at energies near the vacuum level with diffuse molecular orbitals may form nearly-free-electron bands with density maxima in non-nuclear interstitial voids, which are subject to weaker electron-phonon interaction. The position of such bands typically above the frontier orbitals, however, renders them unstable with respect to electronic interband relaxation and therefore unsuitable for charge transport. Through electronic-structure calculations, we engineer stable, non-nuclear, nearly-free-electron conduction channels in low-dimensional molecular materials by tailoring their electrostatic and polarization potentials. We propose quantum structures of graphane-derived Janus molecular sheets with spatially isolated conducting and insulating regions that potentially exhibit emergent electronic properties, as a paradigm for molecular-scale non-nuclear charge conductors; we also describe tuning of their electronic properties by application of external fields and calculate their electron–acoustic-phonon interaction.

  19. Non-nuclear electron transport channels in hollow molecules

    NASA Astrophysics Data System (ADS)

    Zhao, Jin; Petek, Hrvoje

    2014-08-01

    Electron transport in inorganic semiconductors and metals occurs through delocalized bands formed by overlapping electron orbitals. Strong correlation of electronic wave functions with the ionic cores couples the electron and lattice motions, leading to efficient interaction and scattering that degrades coherent charge transport. By contrast, unoccupied electronic states at energies near the vacuum level with diffuse molecular orbitals may form nearly-free-electron bands with density maxima in non-nuclear interstitial voids, which are subject to weaker electron-phonon interaction. The position of such bands typically above the frontier orbitals, however, renders them unstable with respect to electronic interband relaxation and therefore unsuitable for charge transport. Through electronic-structure calculations, we engineer stable, non-nuclear, nearly-free-electron conduction channels in low-dimensional molecular materials by tailoring their electrostatic and polarization potentials. We propose quantum structures of graphane-derived Janus molecular sheets with spatially isolated conducting and insulating regions that potentially exhibit emergent electronic properties, as a paradigm for molecular-scale non-nuclear charge conductors; we also describe tuning of their electronic properties by application of external fields and calculate their electron-acoustic-phonon interaction.

  20. Time-Reversal Symmetry Violation in Molecules Induced by Nuclear Magnetic Quadrupole Moments

    NASA Astrophysics Data System (ADS)

    Flambaum, V. V.; DeMille, D.; Kozlov, M. G.

    2014-09-01

    Recent measurements in paramagnetic molecules improved the limit on the electron electric dipole moment (EDM) by an order of magnitude. Time-reversal (T) and parity (P) symmetry violation in molecules may also come from their nuclei. We point out that nuclear T, P-odd effects are amplified in paramagnetic molecules containing deformed nuclei, where the primary effects arise from the T, P-odd nuclear magnetic quadrupole moment (MQM). We perform calculations of T, P-odd effects in the molecules TaN, ThO, ThF+, HfF+, YbF, HgF, and BaF induced by MQMs. We compare our results with those for the diamagnetic TlF molecule, where the T, P-odd effects are produced by the nuclear Schiff moment. We argue that measurements in molecules with MQMs may provide improved limits on the strength of T, P-odd nuclear forces, on the proton, neutron, and quark EDMs, on quark chromo-EDMs, and on the QCD θ term and CP-violating quark interactions.

  1. Electron-nuclear correlation in above-threshold double ionization of molecules

    NASA Astrophysics Data System (ADS)

    Lu, Peifen; Zhang, Wenbin; Gong, Xiaochun; Song, Qiying; Lin, Kang; Ji, Qinying; Ma, Junyang; He, Feng; Zeng, Heping; Wu, Jian

    2017-03-01

    We report on the experimental observation of photon energy sharing among two electrons and two ions ejected from a doubly ionized molecule exposed to an intense ultraviolet femtosecond laser pulse. Although two electrons are successively released one after the other, bridged by the nuclear motion via their interactions, photon energy sharing among four particles is observed as multiple energy conservation lines in their joint energy spectrum. For sequential double ionization of H2, the electron-nuclear joint energy spectrum allows us to identify three pathways towards the charge-resonance enhanced ionization of the stretching H2+ in strong laser fields. By counting the photon number absorbed by the molecule, we trace the accessibility, enhancement, and suppression of various pathways. The correlated electron-nuclear motion provides profound insights of the complicated strong-field dynamics of molecules.

  2. Measurement of the nuclear polarization of hydrogen and deuterium molecules using a Lamb-shift polarimeter.

    PubMed

    Engels, Ralf; Gorski, Robert; Grigoryev, Kiril; Mikirtychyants, Maxim; Rathmann, Frank; Seyfarth, Hellmut; Ströher, Hans; Weiss, Philipp; Kochenda, Leonid; Kravtsov, Peter; Trofimov, Viktor; Tschernov, Nikolay; Vasilyev, Alexander; Vznuzdaev, Marat; Paetz gen Schieck, Hans

    2014-10-01

    Lamb-shift polarimeters are used to measure the nuclear polarization of protons and deuterons at energies of a few keV. In combination with an ionizer, the polarization of hydrogen and deuterium atoms was determined after taking into account the loss of polarization during the ionization process. The present work shows that the nuclear polarization of hydrogen or deuterium molecules can be measured as well, by ionizing the molecules and injecting the H2(+) (or D2(+)) ions into the Lamb-shift polarimeter.

  3. Measurement of the nuclear polarization of hydrogen and deuterium molecules using a Lamb-shift polarimeter

    SciTech Connect

    Engels, Ralf Gorski, Robert; Grigoryev, Kiril; Mikirtychyants, Maxim; Rathmann, Frank; Seyfarth, Hellmut; Ströher, Hans; Weiss, Philipp; Kochenda, Leonid; Kravtsov, Peter; Trofimov, Viktor; Tschernov, Nikolay; Vasilyev, Alexander; Vznuzdaev, Marat; Schieck, Hans Paetz gen.

    2014-10-15

    Lamb-shift polarimeters are used to measure the nuclear polarization of protons and deuterons at energies of a few keV. In combination with an ionizer, the polarization of hydrogen and deuterium atoms was determined after taking into account the loss of polarization during the ionization process. The present work shows that the nuclear polarization of hydrogen or deuterium molecules can be measured as well, by ionizing the molecules and injecting the H{sub 2}{sup +} (or D{sub 2}{sup +}) ions into the Lamb-shift polarimeter.

  4. Extensive theoretical study on the excited states of the PCl+ molecule including spin-orbit coupling

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaomei; Zhai, Hongsheng; Liu, Siyuan; Liu, Yufang

    2017-07-01

    The entire 23 Λ-S states of the PCl+ molecule have been studied by using the high-level relativistic MRCI+Q method with full-electron aug-cc-pCVQZ-DK basis set. The potential energy curves(PECs) and wavefunctions of the states have been calculated. From the PECs, the spectroscopic constants of the bound states are also determined, and the good agreements could be found with the experiments. The high density region of states exhibits many PECs' crossings, which lead to complicated interaction of the states. Here, the interactions arising from the dipolar interaction and spin-orbit coupling (SOC) effect have been discussed in detail. Under the influence of the SOC effect, the A2Π state is perturbed by the 14Σ- state. Considering the SOC effect, total 45 Ω states are generated from the original 23 Λ-S states. The transition properties are also predicted, including the transition dipole moments, Franck-Condon factors, and radiative lifetimes. The lifetimes of the transitions A2Π1/2-X2Π1/2 and A2Π3/2-X2Π3/2 are determined to be 478.9 ns and 487.0 ns(v'=0), respectively.

  5. Single-point single-molecule FRAP distinguishes inner and outer nuclear membrane protein distribution

    PubMed Central

    Mudumbi, Krishna C; Schirmer, Eric C; Yang, Weidong

    2016-01-01

    The normal distribution of nuclear envelope transmembrane proteins (NETs) is disrupted in several human diseases. NETs are synthesized on the endoplasmic reticulum and then transported from the outer nuclear membrane (ONM) to the inner nuclear membrane (INM). Quantitative determination of the distribution of NETs on the ONM and INM is limited in available approaches, which moreover provide no information about translocation rates in the two membranes. Here we demonstrate a single-point single-molecule FRAP microscopy technique that enables determination of distribution and translocation rates for NETs in vivo. PMID:27558844

  6. Electron Dynamics upon Ionization of Polyatomic Molecules: Coupling to Quantum Nuclear Motion and Decoherence

    NASA Astrophysics Data System (ADS)

    Vacher, Morgane; Bearpark, Michael J.; Robb, Michael A.; Malhado, João Pedro

    2017-02-01

    Knowledge about the electronic motion in molecules is essential for our understanding of chemical reactions and biological processes. The advent of attosecond techniques opens up the possibility to induce electronic motion, observe it in real time, and potentially steer it. A fundamental question remains the factors influencing electronic decoherence and the role played by nuclear motion in this process. Here, we simulate the dynamics upon ionization of the polyatomic molecules paraxylene and modified bismethylene-adamantane, with a quantum mechanical treatment of both electron and nuclear dynamics using the direct dynamics variational multiconfigurational Gaussian method. Our simulations give new important physical insights about the expected decoherence process. We have shown that the decoherence of electron dynamics happens on the time scale of a few femtoseconds, with the interplay of different mechanisms: the dephasing is responsible for the fast decoherence while the nuclear overlap decay may actually help maintain it and is responsible for small revivals.

  7. An independent-atom-model description of ion-molecule collisions including geometric screening corrections

    NASA Astrophysics Data System (ADS)

    Lüdde, Hans Jürgen; Achenbach, Alexander; Kalkbrenner, Thilo; Jankowiak, Hans-Christian; Kirchner, Tom

    2016-04-01

    A new model to account for geometric screening corrections in an independent-atom-model description of ion-molecule collisions is introduced. The ion-molecule cross sections for net capture and net ionization are represented as weighted sums of atomic cross sections with weight factors that are determined from a geometric model of overlapping cross section areas. Results are presented for proton collisions with targets ranging from diatomic to complex polyatomic molecules. Significant improvement compared to simple additivity rule results and in general good agreement with experimental data are found. The flexibility of the approach opens up the possibility to study more detailed observables such as orientation-dependent and charge-state-correlated cross sections for a large class of complex targets ranging from biomolecules to atomic clusters.

  8. Energy-Level Related Nuclear-Spin Effects and Super-Hyperfine Spectral Patterns: how Molecules do Self-Nmr

    NASA Astrophysics Data System (ADS)

    Harter, William; Mitchell, Justin

    2009-06-01

    At several points in his defining works on molecular spectroscopy, Herzberg notes that ``because nuclear moments ldots are so very slight ldots transitions between species ldots are very strictly forbiddenldots '' Herzberg's most recent statement of such selection rules pertained to spherical top spin-species. It has since been shown that spherical top species (as well as those of lower symmetry molecules) converge exponentially with momentum quanta J and K to degenerate level clusters wherein even ``very slight'' nuclear fields and moments cause pervasive resonance and total spin species mixing. Ultra-high resolution spectra of Borde, et .al and Pfister et .al shows how SF_6 and SiF_4 Fluorine nuclear spin levels rearrange from total-spin multiplets to NMR-like patterns as their superfine structure converges. Similar super-hyperfine effects are anticipated for lower symmetry molecules exhibiting converging superfine level-clusters. Examples include PH_3 molecules and asymmetric tops. Following this we consider models that treat nuclear spins as coupled rotors undergoing generalized Hund-case transitions from spin-lab-momentum coupling to various spin-rotor correlations. G. A. Herzberg, Electronic Spectra of Polyatomic Molecules, (Von Norstrand Rheinhold 1966) p. 246. W G. Harter and C. W Patterson, Phys. Rev. A 19, 2277 (1979) W. G. Harter, Phys. Rev. A 24, 192 (1981). Ch. J. Borde, J. Borde, Ch. Breant, Ch. Chardonnet, A. Van Lerberghe, and Ch. Salomon, in Laser Spectroscopy VII, T. W Hensch and Y. R. Shen, eds. (Springer-Verlag, Berlin, 1985). O. Pfister, F. Guernet, G. Charton, Ch. Chardonnet, F. Herlemont, and J. Legrand, J. Opt. Soc. Am. B 10, 1521 (1993). O. Pfister, Ch. Chardonnet, and Ch. J. Bordè, Phys. Rev. Lett. 76, 4516 (1996) S. N. Yurchenko, W. Thiel, S. Patchkovskii, and P. Jensen, Phys. Chem. Chem. Phys.7, 573 (2005)

  9. Small molecule peptidomimetic inhibitors of importin α/β mediated nuclear transport

    PubMed Central

    Ambrus, Géza; Whitby, Landon R.; Singer, Eric L.; Trott, Oleg; Choi, Euna; Olson, Arthur J.; Boger, Dale L.; Gerace, Larry

    2010-01-01

    Nucleocytoplasmic transport of macromolecules is a fundamental process of eukaryotic cells. Translocation of proteins and many RNAs between the nucleus and cytoplasm is carried out by shuttling receptors of the β-karyopherin family, also called importins and exportins. Leptomycin B, a small molecule inhibitor of the exportin CRM1, has proved to be an invaluable tool for cell biologists, but up to now no small molecule inhibitors of nuclear import have been described. We devised a microtiter plate based permeabilized cell screen for small molecule inhibitors of the importin α/β pathway. By analyzing peptidomimetic libraries, we identified β-turn and α-helix peptidomimetic compounds that selectively inhibit nuclear import by importin α/β but not by transportin. Structure-activity relationship analysis showed that large aromatic residues and/or a histidine side chain are required for effective import inhibition by these compounds. Our validated inhibitors can be useful for in vitro studies of nuclear import, and can also provide a framework for synthesis of higher potency nuclear import inhibitors. PMID:20869252

  10. Two-center interferences and nuclear wave packet imaging in dissociating H2+ molecule

    NASA Astrophysics Data System (ADS)

    Picon, Antonio; Bahabad, Alon; Kapteyn, Henry C.; Murnane, Margaret M.; Becker, Andreas

    2011-05-01

    Double-slit like interferences similar to those observed by Young in his experiment with light appear also in the photoionization of diatomic molecules. The partial electron waves ejected from the two atomic centers of the molecule take the role of the coherent light waves emerging from the two holes in Youngs experiment. We analyze theoretically and numerically a pump-probe scenario with two attosecond pulses in the hydrogen molecular ion. The first attosecond pulse induces the dissociation of the molecule, the second attosecond pulse is ionizing the molecule. By varying the delay between the pump and probe pulses we show how the two-center interferences allow to image main features of the nuclear wave packet, namely its velocity, internuclear distance, and spreading. Supported by Postdoctoral Program of the Spanish Government and NSF.

  11. Electronic friction near metal surfaces: A case where molecule-metal couplings depend on nuclear coordinates

    NASA Astrophysics Data System (ADS)

    Dou, Wenjie; Subotnik, Joseph E.

    2017-03-01

    We derive an explicit form for the electronic friction as felt by a molecule near a metal surface for the general case that molecule-metal couplings depend on nuclear coordinates. Our work generalizes a previous study by von Oppen et al. [Beilstein J. Nanotechnol. 3, 144 (2012)], where we now go beyond the Condon approximation (i.e., molecule-metal couplings are not held constant). Using a non-equilibrium Green's function formalism in the adiabatic limit, we show that fluctuating metal-molecule couplings lead to new frictional damping terms and random forces, plus a correction to the potential of mean force. Numerical tests are performed and compared with a modified classical master equation; our results indicate that violating the Condon approximation can have a large effect on dynamics.

  12. Monte Carlo calculations of diatomic molecule gas flows including rotational mode excitation

    NASA Technical Reports Server (NTRS)

    Yoshikawa, K. K.; Itikawa, Y.

    1976-01-01

    The direct simulation Monte Carlo method was used to solve the Boltzmann equation for flows of an internally excited nonequilibrium gas, namely, of rotationally excited homonuclear diatomic nitrogen. The semi-classical transition probability model of Itikawa was investigated for its ability to simulate flow fields far from equilibrium. The behavior of diatomic nitrogen was examined for several different nonequilibrium initial states that are subjected to uniform mean flow without boundary interactions. A sample of 1000 model molecules was observed as the gas relaxed to a steady state starting from three specified initial states. The initial states considered are: (1) complete equilibrium, (2) nonequilibrium, equipartition (all rotational energy states are assigned the mean energy level obtained at equilibrium with a Boltzmann distribution at the translational temperature), and (3) nonequipartition (the mean rotational energy is different from the equilibrium mean value with respect to the translational energy states). In all cases investigated the present model satisfactorily simulated the principal features of the relaxation effects in nonequilibrium flow of diatomic molecules.

  13. Nuclear export of single native mRNA molecules observed by light sheet fluorescence microscopy.

    PubMed

    Siebrasse, Jan Peter; Kaminski, Tim; Kubitscheck, Ulrich

    2012-06-12

    Nuclear export of mRNA is a key transport process in eukaryotic cells. To investigate it, we labeled native mRNP particles in living Chironomus tentans salivary gland cells with fluorescent hrp36, the hnRNP A1 homolog, and the nuclear envelope by fluorescent NTF2. Using light sheet microscopy, we traced single native mRNA particles across the nuclear envelope. The particles were observed to often probe nuclear pore complexes (NPC) at their nuclear face, and in only 25% of the cases yielded actual export. The complete export process took between 65 ms up to several seconds. A rate-limiting step was observed, which could be assigned to the nuclear basket of the pore and might correspond to a repositioning and unfolding of mRNPs before the actual translocation. Analysis of single fluorescent Dbp5 molecules, the RNA helicase essential for mRNA export, revealed that Dbp5 most often approached the cytoplasmic face of the NPC, and exhibited a binding duration of approximately 55 ms. Our results have allowed a refinement of the current models for mRNA export.

  14. Relationship of sea level muon charge ratio to primary composition including nuclear target effects

    NASA Technical Reports Server (NTRS)

    Goned, A.; Shalaby, M.; Salem, A. M.; Roushdy, M.

    1985-01-01

    The discrepancy between the muon charge ratio observed at low energies and that calculated using pp data is removed by including nuclear target effects. Calculations at high energies show that the primary iron spectrum is expected to change slope from 2 to 2.2 to 2.4 to 2.5 for energies approx. 4 x 10 to the 3 GeV/nucleon if scaling features continue to the highest energies.

  15. The kinetic energy operator for distance-dependent effective nuclear masses: Derivation for a triatomic molecule.

    PubMed

    Khoma, Mykhaylo; Jaquet, Ralph

    2017-09-21

    The kinetic energy operator for triatomic molecules with coordinate or distance-dependent nuclear masses has been derived. By combination of the chain rule method and the analysis of infinitesimal variations of molecular coordinates, a simple and general technique for the construction of the kinetic energy operator has been proposed. The asymptotic properties of the Hamiltonian have been investigated with respect to the ratio of the electron and proton mass. We have demonstrated that an ad hoc introduction of distance (and direction) dependent nuclear masses in Cartesian coordinates preserves the total rotational invariance of the problem. With the help of Wigner rotation functions, an effective Hamiltonian for nuclear motion can be derived. In the derivation, we have focused on the effective trinuclear Hamiltonian. All necessary matrix elements are given in closed analytical form. Preliminary results for the influence of non-adiabaticity on vibrational band origins are presented for H3(+).

  16. The kinetic energy operator for distance-dependent effective nuclear masses: Derivation for a triatomic molecule

    NASA Astrophysics Data System (ADS)

    Khoma, Mykhaylo; Jaquet, Ralph

    2017-09-01

    The kinetic energy operator for triatomic molecules with coordinate or distance-dependent nuclear masses has been derived. By combination of the chain rule method and the analysis of infinitesimal variations of molecular coordinates, a simple and general technique for the construction of the kinetic energy operator has been proposed. The asymptotic properties of the Hamiltonian have been investigated with respect to the ratio of the electron and proton mass. We have demonstrated that an ad hoc introduction of distance (and direction) dependent nuclear masses in Cartesian coordinates preserves the total rotational invariance of the problem. With the help of Wigner rotation functions, an effective Hamiltonian for nuclear motion can be derived. In the derivation, we have focused on the effective trinuclear Hamiltonian. All necessary matrix elements are given in closed analytical form. Preliminary results for the influence of non-adiabaticity on vibrational band origins are presented for H3+.

  17. Plant nuclear hormone receptors: a role for small molecules in protein-protein interactions.

    PubMed

    Lumba, Shelley; Cutler, Sean; McCourt, Peter

    2010-01-01

    Plant hormones are a group of chemically diverse small molecules that direct processes ranging from growth and development to biotic and abiotic stress responses. Surprisingly, genome analyses suggest that classic animal nuclear hormone receptor homologs do not exist in plants. It now appears that plants have co-opted several protein families to perceive hormones within the nucleus. In one solution to the problem, the hormones auxin and jasmonate (JA) act as “molecular glue” that promotes protein-protein interactions between receptor F-boxes and downstream corepressor targets. In another solution, gibberellins (GAs) bind and elicit a conformational change in a novel soluble receptor family related to hormone-sensitive lipases. Abscisic acid (ABA), like GA, also acts through an allosteric mechanism involving a START-domain protein. The molecular identification of plant nuclear hormone receptors will allow comparisons with animal nuclear receptors and testing of fundamental questions about hormone function in plant development and evolution.

  18. Second-scale nuclear spin coherence time of ultracold 23Na40K molecules

    NASA Astrophysics Data System (ADS)

    Park, Jee Woo; Yan, Zoe Z.; Loh, Huanqian; Will, Sebastian A.; Zwierlein, Martin W.

    2017-07-01

    Coherence, the stability of the relative phase between quantum states, is central to quantum mechanics and its applications. For ultracold dipolar molecules at sub-microkelvin temperatures, internal states with robust coherence are predicted to offer rich prospects for quantum many-body physics and quantum information processing. We report the observation of stable coherence between nuclear spin states of ultracold fermionic sodium-potassium (NaK) molecules in the singlet rovibrational ground state. Ramsey spectroscopy reveals coherence times on the scale of 1 second; this enables high-resolution spectroscopy of the molecular gas. Collisional shifts are shown to be absent down to the 100-millihertz level. This work opens the door to the use of molecules as a versatile quantum memory and for precision measurements on dipolar quantum matter.

  19. Fully relativistic ab initio calculations of the energies of chiral molecules including parity-violating weak interactions

    NASA Astrophysics Data System (ADS)

    Laerdahl, Jon K.; Schwerdtfeger, Peter

    1999-12-01

    The parity-odd perturbation operator for the inelastic electron-nucleon scattering by weak neutral currents (exchange of virtual Z0 bosons) has been implemented into a fully relativistic four-component Dirac-Hartree-Fock scheme. Dirac-Hartree-Fock electronic structure calculations on H2O2, H2S2, H2Se2, H2Te2, and H2Po2 provides a demonstration of the higher than Z5 scaling of the parity-violating energy shift (Z is the nuclear charge) in chiral molecules. To our knowledge, the calculations for H2Te2 and H2Po2 are the first for molecules containing heavy elements from period 5 or 6 of the Periodic Table, and the parity-violating energy shifts are some of the highest reported in any ab initio study. It has been shown that special care is needed in the basis set expansion of the wave function because of the coupling between the large and small components of the Dirac wave function through the γ5 matrix. Estimates of the remaining errors in the calculations have been given. A comparison with the calculated parity-violating energy shift of H2TeO have confirmed the importance of the single-center theorem, which states that the parity-violating energy shift is suppressed in molecules containing only a single heavy atomic center. Due to the close correspondence between parity-violating energy shifts and observable parity-odd properties, our results have important consequences for the current search for an experimental confirmation of parity-odd effects in molecular physics: (i) The experiments should be performed on molecules containing heavy (period 5 or 6) elements. (ii) Molecules with more than one heavy atomic center will be extremely favorable due to the single-center theorem.

  20. Relativistic calculation of the pion loop correlation energy in nuclear matter in a theory including confinement

    SciTech Connect

    Massot, E.; Chanfray, G.

    2009-07-15

    We present a relativistic calculation of the saturation properties of nuclear matter which contains the correlation energy. Pion loops are incorporated on top of a relativistic Hartree-Fock (RHF) approach based on a chiral theory. It includes the effect of nucleon structure through its response to the background chiral invariant scalar field. All the parameters which enter the RHF calculation are fixed or strongly constrained by hadron phenomenology or lattice data. The new input for the correlation energy is the Landau-Migdal parameter g{sup '} governing the short-range part of the spin-isospin interaction. We find that the inclusion of the correlation energy improves the description of the saturation properties of nuclear matter.

  1. Widespread occurrence of organelle genome-encoded 5S rRNAs including permuted molecules

    PubMed Central

    Valach, Matus; Burger, Gertraud; Gray, Michael W.; Lang, B. Franz

    2014-01-01

    5S Ribosomal RNA (5S rRNA) is a universal component of ribosomes, and the corresponding gene is easily identified in archaeal, bacterial and nuclear genome sequences. However, organelle gene homologs (rrn5) appear to be absent from most mitochondrial and several chloroplast genomes. Here, we re-examine the distribution of organelle rrn5 by building mitochondrion- and plastid-specific covariance models (CMs) with which we screened organelle genome sequences. We not only recover all organelle rrn5 genes annotated in GenBank records, but also identify more than 50 previously unrecognized homologs in mitochondrial genomes of various stramenopiles, red algae, cryptomonads, malawimonads and apusozoans, and surprisingly, in the apicoplast (highly derived plastid) genomes of the coccidian pathogens Toxoplasma gondii and Eimeria tenella. Comparative modeling of RNA secondary structure reveals that mitochondrial 5S rRNAs from brown algae adopt a permuted triskelion shape that has not been seen elsewhere. Expression of the newly predicted rrn5 genes is confirmed experimentally in 10 instances, based on our own and published RNA-Seq data. This study establishes that particularly mitochondrial 5S rRNA has a much broader taxonomic distribution and a much larger structural variability than previously thought. The newly developed CMs will be made available via the Rfam database and the MFannot organelle genome annotator. PMID:25429974

  2. Widespread occurrence of organelle genome-encoded 5S rRNAs including permuted molecules.

    PubMed

    Valach, Matus; Burger, Gertraud; Gray, Michael W; Lang, B Franz

    2014-12-16

    5S Ribosomal RNA (5S rRNA) is a universal component of ribosomes, and the corresponding gene is easily identified in archaeal, bacterial and nuclear genome sequences. However, organelle gene homologs (rrn5) appear to be absent from most mitochondrial and several chloroplast genomes. Here, we re-examine the distribution of organelle rrn5 by building mitochondrion- and plastid-specific covariance models (CMs) with which we screened organelle genome sequences. We not only recover all organelle rrn5 genes annotated in GenBank records, but also identify more than 50 previously unrecognized homologs in mitochondrial genomes of various stramenopiles, red algae, cryptomonads, malawimonads and apusozoans, and surprisingly, in the apicoplast (highly derived plastid) genomes of the coccidian pathogens Toxoplasma gondii and Eimeria tenella. Comparative modeling of RNA secondary structure reveals that mitochondrial 5S rRNAs from brown algae adopt a permuted triskelion shape that has not been seen elsewhere. Expression of the newly predicted rrn5 genes is confirmed experimentally in 10 instances, based on our own and published RNA-Seq data. This study establishes that particularly mitochondrial 5S rRNA has a much broader taxonomic distribution and a much larger structural variability than previously thought. The newly developed CMs will be made available via the Rfam database and the MFannot organelle genome annotator. © The Author(s) 2014. Published by Oxford University Press on behalf of Nucleic Acids Research.

  3. Single-molecule conductance measurements of biomolecule translocation across biomimetic nuclear pores

    NASA Astrophysics Data System (ADS)

    Dekker, Cees

    2012-02-01

    After a brief overview of our recent work on solid-state nanopores, I will present single-molecule transport data across biomimetic nanopores that contain the key regulating parts of the nuclear pore complex (NPC). The mechanism for the remarkable selectivity of NPCs has remained unclear in a large part due to difficulties in designing experiments that can probe the transport at the relevant length and time scales. Building and measuring on biomimetic NPCs provides new opportunities to address this long-standing problem. covalently tether the natively unfolded Phe-Gly rich domains (FG-domains) of human nuclear binding proteins to a solid-state nanopore (a 10-100 nm sized hole in a SiN membrane). Ionic current measurements provide a probe to monitor single molecules that traverse the pore. Translocation events are observed for transport receptors (Impβ), whereas transport of passive molecules (BSA) is found to be blocked. Interestingly, a single type of nuclear pore proteins appears already sufficient to form a selective barrier for transport. A translocation time of about 2.5 ms is measured for Impβ. This time is found to be similar for transport across Nup153 and Nup98 coated pores, although the observed ionic conductance differs between these two types of pores. We compare two simple models for the pore conductance and find, for both Nups, that the data fits best to a model with an open central channel and a condensed layer along the outer circumference of the pore. reproducing the key features of the NPC, our biomimetic approach opens the way to study a wide variety of nucleo-cytoplasmic transport processes at the single-molecule level in vitro.

  4. [Development of asymmetric synthesis of optically active compounds including fluoroorganic molecules].

    PubMed

    Iseki, K

    1999-11-01

    The synthesis of chiral fluorinated molecules is important in the biological and medicinal chemistry fields in view of the influence of fluorine's unique properties on biological activity. In recent years, we have studied asymmetric synthesis focussing on such optically active compounds. This review describes 1) diastereoselective trifluoromethylation of chiral N-acyloxazolidinones, 2) catalytic enantioselective aldol reactions of fluorine-substituted ketene silyl acetals, and 3) catalytic enantioselective allylation of aldehydes mediated by chiral Lewis bases. The trifluoromethylation of lithium enolates of N-acyloxazolidinones with iodotrifluoromethane is mediated by triethylborane to give the corresponding trifluoromethylated products with up to 86% diastereomeric excess. The stereoselective reaction is considered to proceed through the attack of the trifluoromethyl radical on the less hindered face of the lithium imide. Difluoroketene and bromofluoroketene trimethylsilyl ethyl acetals react with various aldehydes in the presence of chiral Lewis acids to afford the corresponding desired aldols with up to 99% enantiomeric excess (ee). It is noteworthy that the aldol reactions of the fluorine-substituted acetals at -78 degrees C and at higher temperatures (-45 or -20 degrees C) provide the (+)- and (-)-aldols, respectively, with excellent-to-good enantioselectivity. Chiral phosphoramides newly prepared from (S)-proline were found to catalyze the allylation and crotylation of aromatic aldehydes with allylic trichlorosilanes in good enantioselective yields (up to 90% ee). (S,S)-Bis(alpha-methylbenzyl)formamide developed as an efficient catalyst for the allylation and crotylation of aliphatic aldehydes mediates the enantioselective addition with the assistance of hexamethylphosphoramide (HMPA) to afford the corresponding homoallylic alcohols in up to 98% ee.

  5. Nonseparable exchange–correlation functional for molecules, including homogeneous catalysis involving transition metals

    SciTech Connect

    Yu, Haoyu S.; Zhang, Wenjing; Verma, Pragya; He, Xiao; Truhlar, Donald G.

    2015-01-01

    The goal of this work is to develop a gradient approximation to the exchange–correlation functional of Kohn–Sham density functional theory for treating molecular problems with a special emphasis on the prediction of quantities important for homogeneous catalysis and other molecular energetics. Our training and validation of exchange–correlation functionals is organized in terms of databases and subdatabases. The key properties required for homogeneous catalysis are main group bond energies (database MGBE137), transition metal bond energies (database TMBE32), reaction barrier heights (database BH76), and molecular structures (database MS10). We also consider 26 other databases, most of which are subdatabases of a newly extended broad database called Database 2015, which is presented in the present article and in its ESI. Based on the mathematical form of a nonseparable gradient approximation (NGA), as first employed in the N12 functional, we design a new functional by using Database 2015 and by adding smoothness constraints to the optimization of the functional. The resulting functional is called the gradient approximation for molecules, or GAM. The GAM functional gives better results for MGBE137, TMBE32, and BH76 than any available generalized gradient approximation (GGA) or than N12. The GAM functional also gives reasonable results for MS10 with an MUE of 0.018 Å. The GAM functional provides good results both within the training sets and outside the training sets. The convergence tests and the smooth curves of exchange–correlation enhancement factor as a function of the reduced density gradient show that the GAM functional is a smooth functional that should not lead to extra expense or instability in optimizations. NGAs, like GGAs, have the advantage over meta-GGAs and hybrid GGAs of respectively smaller grid-size requirements for integrations and lower costs for extended systems. These computational advantages combined with the relatively high accuracy

  6. Nonseparable exchange-correlation functional for molecules, including homogeneous catalysis involving transition metals.

    PubMed

    Yu, Haoyu S; Zhang, Wenjing; Verma, Pragya; He, Xiao; Truhlar, Donald G

    2015-05-14

    The goal of this work is to develop a gradient approximation to the exchange-correlation functional of Kohn-Sham density functional theory for treating molecular problems with a special emphasis on the prediction of quantities important for homogeneous catalysis and other molecular energetics. Our training and validation of exchange-correlation functionals is organized in terms of databases and subdatabases. The key properties required for homogeneous catalysis are main group bond energies (database MGBE137), transition metal bond energies (database TMBE32), reaction barrier heights (database BH76), and molecular structures (database MS10). We also consider 26 other databases, most of which are subdatabases of a newly extended broad database called Database 2015, which is presented in the present article and in its ESI. Based on the mathematical form of a nonseparable gradient approximation (NGA), as first employed in the N12 functional, we design a new functional by using Database 2015 and by adding smoothness constraints to the optimization of the functional. The resulting functional is called the gradient approximation for molecules, or GAM. The GAM functional gives better results for MGBE137, TMBE32, and BH76 than any available generalized gradient approximation (GGA) or than N12. The GAM functional also gives reasonable results for MS10 with an MUE of 0.018 Å. The GAM functional provides good results both within the training sets and outside the training sets. The convergence tests and the smooth curves of exchange-correlation enhancement factor as a function of the reduced density gradient show that the GAM functional is a smooth functional that should not lead to extra expense or instability in optimizations. NGAs, like GGAs, have the advantage over meta-GGAs and hybrid GGAs of respectively smaller grid-size requirements for integrations and lower costs for extended systems. These computational advantages combined with the relatively high accuracy for all

  7. A molecular dynamics study of nuclear quantum effect on diffusivity of hydrogen molecule

    NASA Astrophysics Data System (ADS)

    Nagashima, H.; Tsuda, S.; Tsuboi, N.; Hayashi, A. K.; Tokumasu, T.

    2017-07-01

    In this paper, the nuclear quantum effect of the hydrogen molecule on its diffusivity was analyzed using the molecular dynamics (MD) method. The centroid MD (CMD) method was applied to reproduce the time evolution of the molecules. The diffusion coefficient of hydrogen was calculated using the Green-Kubo method over a wide temperature region, and the temperature dependence of the quantum effect of the hydrogen molecule on its diffusivity was addressed. The calculated results were compared with classical MD results based on the principle of corresponding state (PCS). It was confirmed that the difference in the diffusion coefficient calculated in the CMD and classical MD methods was small, and the PCS appears to be satisfied on the temperature dependence of the diffusion coefficient, even though the quantum effect of the hydrogen molecules was taken into account. It was clarified that this result did not suggest that the quantum effect on the diffusivity of the hydrogen molecule was small but that the two changes in the intermolecular interaction of hydrogen due to the quantum effect offset each other. Moreover, it was found that this tendency was related to the temperature dependence of the ratio of the kinetic energy of the quantum fluctuational motion to the classical kinetic energy.

  8. PPAR δ agonist GW0742 interacts weakly with multiple nuclear receptors including the vitamin D receptor

    PubMed Central

    Nandhikonda, Premchendar; Yasgar, Adam; Baranowski, Athena M.; Sidhu, Preetpal S.; McCallum, Megan M.; Pawlak, Alan J.; Teske, Kelly; Feleke, Belaynesh; Yuan, Nina Y.; Kevin, Chinedum; Bikle, Daniel D.; Ayers, Steven D.; Webb, Paul; Rai, Ganesha; Simeonov, Anton; Jadhav, Ajit; Maloney, David; Arnold, Leggy A.

    2013-01-01

    A high throughput screening campaign was conducted to identify small molecules with the ability to inhibit the interaction between the vitamin D receptor (VDR) and steroid receptor coactivator 2. These inhibitors represent novel molecular probes to modulate gene regulation mediated by VDR. The peroxisome proliferator-activated receptor δ (PPARδ) agonist GW0742 was among the identified VDR-coactivator inhibitors and has been characterized herein as a pan nuclear receptor antagonist at concentrations higher than 12.1 µM. The highest antagonist activity for GW0742 was found for VDR and the androgen receptor (AR). Surprisingly, GW0742 behaved as PPAR agonist/antagonist activating transcription at lower concentration and inhibiting this effect at higher concentrations. A unique spectroscopic property of GW0742 was identified as well. In the presence of rhodamine-derived molecules, GW0742+ increased fluorescence intensity and fluorescence polarization at an excitation wavelength of 595 nm and emission wavelength of 615 nm in a dose dependent manner. The GW0742-inhibited NR-coactivator binding resulted in a reduced expression of five different NR target genes in LNCaP cells in the presence of agonist. Especially VDR target genes CYP24A1, IGFBP-3 and TRPV6 were negatively regulated by GW0742. GW0742 is the first VDR ligand inhibitor lacking the secosteroid structure of VDR ligand antagonists. Nevertheless, the VDR-meditated downstream process of cell differentiation was antagonized by GW0742 in HL-60 cells that were pretreated with the endogenous VDR agonist 1,25-dihydroxyvitamin D3. PMID:23713684

  9. Neutron monitoring systems including gamma thermometers and methods of calibrating nuclear instruments using gamma thermometers

    DOEpatents

    Moen, Stephan Craig; Meyers, Craig Glenn; Petzen, John Alexander; Foard, Adam Muhling

    2012-08-07

    A method of calibrating a nuclear instrument using a gamma thermometer may include: measuring, in the instrument, local neutron flux; generating, from the instrument, a first signal proportional to the neutron flux; measuring, in the gamma thermometer, local gamma flux; generating, from the gamma thermometer, a second signal proportional to the gamma flux; compensating the second signal; and calibrating a gain of the instrument based on the compensated second signal. Compensating the second signal may include: calculating selected yield fractions for specific groups of delayed gamma sources; calculating time constants for the specific groups; calculating a third signal that corresponds to delayed local gamma flux based on the selected yield fractions and time constants; and calculating the compensated second signal by subtracting the third signal from the second signal. The specific groups may have decay time constants greater than 5.times.10.sup.-1 seconds and less than 5.times.10.sup.5 seconds.

  10. Photo Library of the Nevada Site Office (Includes historical archive of nuclear testing images)

    DOE Data Explorer

    The Nevada Site Office makes available publicly released photos from their archive that includes photos from both current programs and historical activities. The historical collections include atmospheric and underground nuclear testing photos and photos of other events and people related to the Nevada Test Site. Current collections are focused on homeland security, stockpile stewardship, and environmental management and restoration. See also the Historical Film Library at http://www.nv.doe.gov/library/films/testfilms.aspx and the Current Film Library at http://www.nv.doe.gov/library/films/current.aspx. Current films can be viewed online, but only short clips of the historical films are viewable. They can be ordered via an online request form for a very small shipping and handling fee.

  11. Rapid multipoint linkage analysis of recessive traits in nuclear families, including homozygosity mapping

    SciTech Connect

    Kruglyak, L.; Daly, M.J.; Lander, E.S. |

    1995-02-01

    Homozygosity mapping is a powerful strategy for mapping rare recessive traits in children of consanguineous marriages. Practical applications of this strategy are currently limited by the inability of conventional linkage analysis software to compute, in reasonable time, multipoint LOD scores for pedigrees with inbreeding loops. We have developed a new algorithm for rapid multipoint likelihood calculations in small pedigrees, including those with inbreeding loops. The running time of the algorithm grows, at most, linearly with the number of loci considered simultaneously. The running time is not sensitive to the presence of inbreeding loops, missing genotype information, and highly polymorphic loci. We have incorporated this algorithm into a software package, MAPMAKER/HOMOZ, that allows very rapid multipoint mapping of disease genes in nuclear families, including homozygosity mapping. Multipoint analysis with dozens of markers can be carried out in minutes on a personal workstation. 23 refs., 4 figs., 1 tab.

  12. Searches for new interstellar molecules, including a tentative detection of aziridine and a possible detection of propenal

    NASA Astrophysics Data System (ADS)

    Dickens, J. E.; Irvine, W. M.; Nummelin, A.; Møllendal, H.; Saito, S.; Thorwirth, S.; Hjalmarson, Å.; Ohishi, M.

    2001-03-01

    Rotational spectroscopy at millimeter wavelengths is a powerful means of investigating the chemistry of dense interstellar clouds. These regions can exhibit an interesting complement of gas phase molecules, including relatively complex organics. Here we report the tentative first astronomical detection of aziridine (ethylenimine), the possible detection of propenal (acrolein), and upper limits on the abundances of cyclopropenone, furan, hydroxyethanal (glycolaldehyde), thiohydroxylamine (NH 2SH), and ethenol (vinyl alcohol) in various interstellar clouds.

  13. Searches for new interstellar molecules, including a tentative detection of aziridine and a possible detection of propenal

    NASA Technical Reports Server (NTRS)

    Dickens, J. E.; Irvine, W. M.; Nummelin, A.; Mollendal, H.; Saito, S.; Thorwirth, S.; Hjalmarson, A.; Ohishi, M.

    2001-01-01

    Rotational spectroscopy at millimeter wavelengths is a powerful means of investigating the chemistry of dense interstellar clouds. These regions can exhibit an interesting complement of gas phase molecules, including relatively complex organics. Here we report the tentative first astronomical detection of aziridine (ethylenimine), the possible detection of propenal (acrolein), and upper limits on the abundances of cyclopropenone, furan, hydroxyethanal (glycolaldehyde), thiohydroxylamine (NH2SH), and ethenol (vinyl alcohol) in various interstellar clouds.

  14. Searches for new interstellar molecules, including a tentative detection of aziridine and a possible detection of propenal

    NASA Technical Reports Server (NTRS)

    Dickens, J. E.; Irvine, W. M.; Nummelin, A.; Mollendal, H.; Saito, S.; Thorwirth, S.; Hjalmarson, A.; Ohishi, M.

    2001-01-01

    Rotational spectroscopy at millimeter wavelengths is a powerful means of investigating the chemistry of dense interstellar clouds. These regions can exhibit an interesting complement of gas phase molecules, including relatively complex organics. Here we report the tentative first astronomical detection of aziridine (ethylenimine), the possible detection of propenal (acrolein), and upper limits on the abundances of cyclopropenone, furan, hydroxyethanal (glycolaldehyde), thiohydroxylamine (NH2SH), and ethenol (vinyl alcohol) in various interstellar clouds.

  15. Theoretical methods for attosecond electron and nuclear dynamics: applications to the H2 molecule

    NASA Astrophysics Data System (ADS)

    Palacios, Alicia; Sanz-Vicario, José Luis; Martín, Fernando

    2015-12-01

    Attosecond science, born at the beginning of this century with the generation of the first bursts of light with durations shorter than a femtosecond, has opened the way to look at electron dynamics in atoms and molecules at its natural timescale. Thus controlling chemical reactions at the electronic level or obtaining time-resolved images of the electronic motion has become a goal for many physics and chemistry laboratories all over the world. The new experimental capabilities have spurred the development of sophisticated theoretical methods that can accurately predict phenomena occurring in the sub-fs timescale. This review provides an overview of the capabilities of existing theoretical tools to describe electron and nuclear dynamics resulting from the interaction of femto- and attosecond UV/XUV radiation with simple molecular targets. We describe one of these methods in more detail, the time-dependent Feshbach close-coupling (TDFCC) formalism, which has been used successfully over the years to investigate various attosecond phenomena in the hydrogen molecule and can easily be extended to other diatomics. In addition to describing the details of the method and discussing its advantages and limitations, we also provide examples of the new physics that one can learn by applying it to different problems: from the study of the autoionization decay that follows attosecond UV excitation to the imaging of the coupled electron and nuclear dynamics in H2 using different UV-pump/IR-probe and UV-pump/UV-probe schemes.

  16. Nuclear molecule formation and time delay in collisions of nuclei with Z1 + Z2 ≥ 110

    NASA Astrophysics Data System (ADS)

    Heinz, S.; Beliuskina, O.; Comas, V.; Devaraja, H. M.; Heinz, C.; Hofmann, S.; Kozulin, E.; Morherr, F.; Münzenberg, G.; Ackermann, D.; Heßberger, F. P.; Kindler, B.; Lommel, B.; Mann, R.; Maurer, J.

    2015-11-01

    We investigated the formation of nuclear molecules and the occurrence of time delays in reactions of the superheavy systems 64Ni + 207Pb ( Z1+Z2=110), 132Xe + 208Pb ( Z1+Z2=136) and 238U + 238U ( Z1+Z2=184. In deep inelastic binary reactions of Ni + Pb and Xe + Pb we observed clear signatures for the formation of long-living molecule-like nuclear systems which rotate by large angles of 180 degree. The evolution of the nuclear molecules was accompanied by large energy dissipation and a strong deformation of the nuclear system. The results from the giant system U + U revealed striking similarities to the ones from Ni + Pb and Xe + Pb , showing that significant time delays still occur in the heaviest accessible systems. The experiments were performed at the velocity filter SHIP at GSI and at the VAMOS spectrometer at GANIL.

  17. Ionization potential of {sup 9}Be calculated including nuclear motion and relativistic corrections

    SciTech Connect

    Stanke, Monika; Kedziera, Dariusz; Bubin, Sergiy; Adamowicz, Ludwik

    2007-05-15

    Variational calculations employing explicitly correlated Gaussian functions have been performed for the ground states of {sup 9}Be and {sup 9}Be{sup +} including the nuclear motion [i.e., without assuming the Born-Oppenheimer (BO) approximation]. An approach based on the analytical energy gradient calculated with respect to the Gaussian exponential parameters was employed, leading to energies of the two systems noticeably improved over those found in the recent paper of Pachucki and Komasa [Phys. Rev. A 73, 052502 (2006)]. The non-BO wave functions were used to calculate the {alpha}{sup 2} relativistic corrections ({alpha}=e{sup 2}/({Dirac_h}/2{pi})c). With those corrections and the {alpha}{sup 3} and {alpha}{sup 4} corrections taken from Pachucki and Komasa, a new value of the ionization potential (IP) of {sup 9}Be was determined. It agrees very well with the most recent experimental IP.

  18. Molecular mechanisms of action of the soy isoflavones includes activation of promiscuous nuclear receptors. A review.

    PubMed

    Ricketts, Marie-Louise; Moore, David D; Banz, William J; Mezei, Orsolya; Shay, Neil F

    2005-06-01

    Consumption of soy has been demonstrated to reduce circulating cholesterol levels, most notably reducing low-density lipoprotein (LDL) cholesterol levels in hypercholesterolemic individuals. The component or components that might be responsible for this effect is still a matter of debate or controversy among many researchers. Candidate agents include an activity of soy protein itself, bioactive peptides produced during the digestive process, or the soy isoflavones. Although soy intake may provide other health benefits including preventative or remediative effects on cancer, osteoporosis and symptoms of menopause, this review will focus on isoflavones as agents affecting lipid metabolism. Isoflavones were first discovered as a bioactive agent disrupting estrogen action in female sheep, thereby earning the often-used term 'phytoestrogens'. Subsequent work confirmed the ability of isoflavones to bind to estrogen receptors. Along with the cholesterol-lowering effect of soy intake, research that is more recent has pointed to a beneficial antidiabetic effect of soy intake, perhaps mediated by soy isoflavones. The two common categories of antidiabetic drugs acting on nuclear receptors known as peroxisome proliferator activated receptors (PPARs) are the fibrates and glitazones. We and others have recently asked the research question 'do the soy isoflavones have activities as either "phytofibrates" or "phytoglitazones"?' Such an activity should be able to be confirmed both in vivo and in vitro. In both the in vivo and in vitro cases, this action has indeed been confirmed. Further work suggests a possible action of isoflavones similar to the nonestrogenic ligands that bind the estrogen-related receptors (ERRs). Recently, these receptors have been demonstrated to contribute to lipolytic processes. Finally, evaluation of receptor activation studies suggests that thyroid receptor activation may provide additional clues explaining the metabolic action of isoflavones. The recent

  19. A general nuclear magnetic resonance analysis of hetero-association of aromatic molecules in aqueous solution

    NASA Astrophysics Data System (ADS)

    Veselkov, Alexei N.; Evstigneev, Maxim P.; Veselkov, Dennis A.; Davies, David B.

    2001-08-01

    A general nuclear magnetic resonance analysis of a statistical-thermodynamical model of hetero-association of aromatic molecules in solution has been developed to take "edge effects" into consideration, i.e., the dependence of proton chemical shifts on the position of the molecule situated inside or at the edge of the aggregate. This generalized approach is compared with a previously published model, where an average contribution to proton shielding is considered irrespective of the position of the molecule in the stack. Association parameters have been determined from experimental concentration and temperature dependences of 500 MHz proton chemical shifts of the hetero-association of the acridine dye, proflavine, and the phenanthridinium dye, ethidium bromide, in aqueous solution. Differences in the parameters in the range 10%-30% calculated using the basic and generalized approaches have been found to depend substantially on the magnitude of the equilibrium hetero-association constant Khet—the larger the value of Khet, the higher the discrepancy between the two methods.

  20. Improved best estimate plus uncertainty methodology including advanced validation concepts to license evolving nuclear reactors

    SciTech Connect

    Unal, Cetin; Williams, Brian; Mc Clure, Patrick; Nelson, Ralph A

    2010-01-01

    Many evolving nuclear energy programs plan to use advanced predictive multi-scale multi-physics simulation and modeling capabilities to reduce cost and time from design through licensing. Historically, the role of experiments was primary tool for design and understanding of nuclear system behavior while modeling and simulation played the subordinate role of supporting experiments. In the new era of multi-scale multi-physics computational based technology development, the experiments will still be needed but they will be performed at different scales to calibrate and validate models leading predictive simulations. Cost saving goals of programs will require us to minimize the required number of validation experiments. Utilization of more multi-scale multi-physics models introduces complexities in the validation of predictive tools. Traditional methodologies will have to be modified to address these arising issues. This paper lays out the basic aspects of a methodology that can be potentially used to address these new challenges in design and licensing of evolving nuclear technology programs. The main components of the proposed methodology are verification, validation, calibration, and uncertainty quantification. An enhanced calibration concept is introduced and is accomplished through data assimilation. The goal is to enable best-estimate prediction of system behaviors in both normal and safety related environments. To achieve this goal requires the additional steps of estimating the domain of validation and quantification of uncertainties that allow for extension of results to areas of the validation domain that are not directly tested with experiments, which might include extension of the modeling and simulation (M&S) capabilities for application to full-scale systems. The new methodology suggests a formalism to quantify an adequate level of validation (predictive maturity) with respect to required selective data so that required testing can be minimized for cost

  1. Angstrom-Resolution Magnetic Resonance Imaging of Single Molecules via Wave-Function Fingerprints of Nuclear Spins

    NASA Astrophysics Data System (ADS)

    Ma, Wen-Long; Liu, Ren-Bao

    2016-08-01

    Single-molecule sensitivity of nuclear magnetic resonance (NMR) and angstrom resolution of magnetic resonance imaging (MRI) are the highest challenges in magnetic microscopy. Recent development in dynamical-decoupling- (DD) enhanced diamond quantum sensing has enabled single-nucleus NMR and nanoscale NMR. Similar to conventional NMR and MRI, current DD-based quantum sensing utilizes the "frequency fingerprints" of target nuclear spins. The frequency fingerprints by their nature cannot resolve different nuclear spins that have the same noise frequency or differentiate different types of correlations in nuclear-spin clusters, which limit the resolution of single-molecule MRI. Here we show that this limitation can be overcome by using "wave-function fingerprints" of target nuclear spins, which is much more sensitive than the frequency fingerprints to the weak hyperfine interaction between the targets and a sensor under resonant DD control. We demonstrate a scheme of angstrom-resolution MRI that is capable of counting and individually localizing single nuclear spins of the same frequency and characterizing the correlations in nuclear-spin clusters. A nitrogen-vacancy-center spin sensor near a diamond surface, provided that the coherence time is improved by surface engineering in the near future, may be employed to determine with angstrom resolution the positions and conformation of single molecules that are isotope labeled. The scheme in this work offers an approach to breaking the resolution limit set by the "frequency gradients" in conventional MRI and to reaching the angstrom-scale resolution.

  2. Cytoplasmic-Nuclear Trafficking of G1/S Cell Cycle Molecules and Adult Human β-Cell Replication

    PubMed Central

    Fiaschi-Taesch, Nathalie M.; Kleinberger, Jeffrey W.; Salim, Fatimah G.; Troxell, Ronnie; Wills, Rachel; Tanwir, Mansoor; Casinelli, Gabriella; Cox, Amy E.; Takane, Karen K.; Srinivas, Harish; Scott, Donald K.; Stewart, Andrew F.

    2013-01-01

    Harnessing control of human β-cell proliferation has proven frustratingly difficult. Most G1/S control molecules, generally presumed to be nuclear proteins in the human β-cell, are in fact constrained to the cytoplasm. Here, we asked whether G1/S molecules might traffic into and out of the cytoplasmic compartment in association with activation of cell cycle progression. Cdk6 and cyclin D3 were used to drive human β-cell proliferation and promptly translocated into the nucleus in association with proliferation. In contrast, the cell cycle inhibitors p15, p18, and p19 did not alter their location, remaining cytoplasmic. Conversely, p16, p21, and p27 increased their nuclear frequency. In contrast once again, p57 decreased its nuclear frequency. Whereas proliferating β-cells contained nuclear cyclin D3 and cdk6, proliferation generally did not occur in β-cells that contained nuclear cell cycle inhibitors, except p21. Dynamic cytoplasmic-nuclear trafficking of cdk6 was confirmed using green fluorescent protein–tagged cdk6 and live cell imaging. Thus, we provide novel working models describing the control of cell cycle progression in the human β-cell. In addition to known obstacles to β-cell proliferation, cytoplasmic-to-nuclear trafficking of G1/S molecules may represent an obstacle as well as a therapeutic opportunity for human β-cell expansion. PMID:23493571

  3. Electron and nuclear dynamics in many-electron atoms, molecules and chlorophyll-protein complexes: a review.

    PubMed

    Shuvalov, Vladimir A

    2007-06-01

    It has been shown [V.A. Shuvalov, Quantum dynamics of electrons in many-electron atoms of biologically important compounds, Biochemistry (Mosc.) 68 (2003) 1333-1354; V.A. Shuvalov, Quantum dynamics of electrons in atoms of biologically important molecules, Uspekhi biologicheskoi khimii, (Pushchino) 44 (2004) 79-108] that the orbit angular momentum L of each electron in many-electron atoms is L=mVr=nPlanck's and similar to L for one-electron atom suggested by N. Bohr. It has been found that for an atom with N electrons the total electron energy equation E=-(Z(eff))(2)e(4)m/(2n(2)Planck's(2)N) is more appropriate for energy calculation than standard quantum mechanical expressions. It means that the value of L of each electron is independent of the presence of other electrons in an atom and correlates well to the properties of virtual photons emitted by the nucleus and creating a trap for electrons. The energies for elements of the 1st up to the 5th rows and their ions (total amount 240) of Mendeleev' Periodical table were calculated consistent with the experimental data (deviations in average were 5 x 10(-3)). The obtained equations can be used for electron dynamics calculations in molecules. For H(2) and H(2)(+) the interference of electron-photon orbits between the atoms determines the distances between the nuclei which are in agreement with the experimental values. The formation of resonance electron-photon orbit in molecules with the conjugated bonds, including chlorophyll-like molecules, appears to form a resonance trap for an electron with E values close to experimental data. Two mechanisms were suggested for non-barrier primary charge separation in reaction centers (RCs) of photosynthetic bacteria and green plants by using the idea of electron-photon orbit interference between the two molecules. Both mechanisms are connected to formation of the exciplexes of chlorophyll-like molecules. The first one includes some nuclear motion before exciplex formation, the

  4. Ribosome-dependent conversion of polyA-containing heterogenous nuclear RNA into smaller RNA molecules.

    PubMed Central

    Grozdanovic, J; Hradec, J

    1975-01-01

    The polyA-containing heterogenous nuclear RNA fraction separated from total rat liver nRNA by gel filtration on Sepharose 4B followed by affinity chromatography on polyU-Sepharose and containing predominantly the 45S components becomes enzymatically bound to homologous 80S ribosomes and polyribosomes at 0 degree C. If 80S ribosomes or polyribosomes with bound poly-a-containing HnRNA are subjected to a further incubation at 37 degree C, the original 45S RNA is gradually converted into smaller RNA species of 10- 35S which remain bound to the particle. This ribosome-dependent cleavage of larger HnRNA species into smaller RNA molecules may represent the ultimate step of mRNA maturation. PMID:1144064

  5. Mimetics of caloric restriction include agonists of lipid-activated nuclear receptors.

    PubMed

    Corton, J Christopher; Apte, Udayan; Anderson, Steven P; Limaye, Pallavi; Yoon, Lawrence; Latendresse, John; Dunn, Corrie; Everitt, Jeffrey I; Voss, Kenneth A; Swanson, Cynthia; Kimbrough, Carie; Wong, Jean S; Gill, Sarjeet S; Chandraratna, Roshantha A S; Kwak, Mi-Kyoung; Kensler, Thomas W; Stulnig, Thomas M; Steffensen, Knut R; Gustafsson, Jan-Ake; Mehendale, Harihara M

    2004-10-29

    The obesity epidemic in industrialized countries is associated with increases in cardiovascular disease (CVD) and certain types of cancer. In animal models, caloric restriction (CR) suppresses these diseases as well as chemical-induced tissue damage. These beneficial effects of CR overlap with those altered by agonists of nuclear receptors (NR) under control of the fasting-responsive transcriptional co-activator, peroxisome proliferator-activated co-activator 1alpha (PGC-1alpha). In a screen for compounds that mimic CR effects in the liver, we found statistically significant overlaps between the CR transcript profile in wild-type mice and the profiles altered by agonists of lipid-activated NR, including peroxisome proliferator-activated receptor alpha (PPARalpha), liver X receptor, and their obligate heterodimer partner, retinoid X receptor. The overlapping genes included those involved in CVD (lipid metabolism and inflammation) and cancer (cell fate). Based on this overlap, we hypothesized that some effects of CR are mediated by PPARalpha. As determined by transcript profiling, 19% of all gene expression changes in wild-type mice were dependent on PPARalpha, including Cyp4a10 and Cyp4a14, involved in fatty acid omega-oxidation, acute phase response genes, and epidermal growth factor receptor but not increases in PGC-1alpha. CR protected the livers of wild-type mice from damage induced by thioacetamide, a liver toxicant and hepatocarcinogen. CR protection was lost in PPARalpha-null mice due to inadequate tissue repair. These results demonstrate that PPARalpha mediates some of the effects of CR and indicate that a pharmacological approach to mimicking many of the beneficial effects of CR may be possible.

  6. A comparative assessment of the economics of plutonium disposition including comparison with other nuclear fuel cycles

    SciTech Connect

    Williams, K.A.; Miller, J.W.; Reid, R.L.

    1997-05-01

    DOE has been evaluating three technologies for the disposition of approximately 50 metric tons of surplus plutonium from defense-related programs: reactors, immobilization, and deep boreholes. As part of the process supporting an early CY 1997 Record of Decision (ROD), a comprehensive assessment of technical viability, cost, and schedule has been conducted. Oak Ridge National Laboratory has managed and coordinated the life-cycle cost (LCC) assessment effort for this program. This paper discusses the economic analysis methodology and the results prior to ROD. Other objectives of the paper are to discuss major technical and economic issues that impact plutonium disposition cost and schedule. Also to compare the economics of a once-through weapons-derived MOX nuclear fuel cycle to other fuel cycles, such as those utilizing spent fuel reprocessing. To evaluate the economics of these technologies on an equitable basis, a set of cost estimating guidelines and a common cost-estimating format were utilized by all three technology teams. This paper also includes the major economic analysis assumptions and the comparative constant-dollar and discounted-dollar LCCs.

  7. Four-component relativistic theory for nuclear magnetic shielding: magnetically balanced gauge-including atomic orbitals.

    PubMed

    Cheng, Lan; Xiao, Yunlong; Liu, Wenjian

    2009-12-28

    It is recognized only recently that the incorporation of the magnetic balance condition is absolutely essential for four-component relativistic theories of magnetic properties. Another important issue to be handled is the so-called gauge problem in calculations of, e.g., molecular magnetic shielding tensors with finite bases. It is shown here that the magnetic balance can be adapted to distributed gauge origins, leading to, e.g., magnetically balanced gauge-including atomic orbitals (MB-GIAOs) in which each magnetically balanced atomic orbital has its own local gauge origin placed on its center. Such a MB-GIAO scheme can be combined with any level of theory for electron correlation. The first implementation is done here at the coupled-perturbed Dirac-Kohn-Sham level. The calculated molecular magnetic shielding tensors are not only independent of the choice of gauge origin but also converge rapidly to the basis set limit. Close inspections reveal that (zeroth order) negative energy states are only important for the expansion of first order electronic core orbitals. Their contributions to the paramagnetism are therefore transferable from atoms to molecule and are essentially canceled out for chemical shifts. This allows for simplifications of the coupled-perturbed equations.

  8. Systematic theoretical study of non-nuclear electron density maxima in some diatomic molecules.

    PubMed

    Terrabuio, Luiz A; Teodoro, Tiago Q; Rachid, Marina G; Haiduke, Roberto L A

    2013-10-10

    First, exploratory calculations were performed to investigate the presence of non-nuclear maxima (NNMs) in ground-state electron densities of homonuclear diatomic molecules from hydrogen up to calcium at their equilibrium geometries. In a second stage, only for the cases in which these features were previously detected, a rigorous analysis was carried out by several combinations of theoretical methods and basis sets in order to ensure that they are not only calculation artifacts. Our best results support that Li2, B2, C2, and P2 are molecules that possess true NNMs. A NNM was found in values obtained from the largest basis sets for Na2, but it disappeared at the experimental geometry because optimized bond lengths are significantly inaccurate for this case (deviations of 0.10 Å). Two of these maxima are also observed in Si2 with CCSD and large basis sets, but they are no longer detected as core-valence correlation or multiconfigurational wave functions are taken into account. Therefore, the NNMs in Si2 can be considered unphysical features due to an incomplete treatment of electron correlation. Finally, we show that a NNM is encountered in LiNa, representing the first discovery of such electron density maxima in a heteronuclear diatomic system at its equilibrium geometry, to our knowledge. Some results for LiNa, found in variations in internuclear distances, suggest that molecular electric moments, such as dipole and quadrupole, are sensitive to the presence of NNMs.

  9. Detection of molecules and cells using nuclear magnetic resonance with magnetic nanoparticles

    NASA Astrophysics Data System (ADS)

    Rümenapp, Christine; Gleich, Bernhard; Mannherz, Hans Georg; Haase, Axel

    2015-04-01

    For the detection of small molecules, proteins or even cells in vitro, functionalised magnetic nanoparticles and nuclear magnetic resonance measurements can be applied. In this work, magnetic nanoparticles with the size of 5-7 nm were functionalised with antibodies to detect two model systems of different sizes, the protein avidin and Saccharomyces cerevisiae as the model organism. The synthesised magnetic nanoparticles showed a narrow size distribution, which was determined using transmission electron microscopy and dynamic light scattering. The magnetic nanoparticles were functionalised with the according antibodies via EDC/NHS chemistry. The binding of the antigen to magnetic nanoparticles was detected through the change in the NMR T2 relaxation time at 0.5 T (≈21.7 MHz). In case of a specific binding the particles cluster and the T2 relaxation time of the sample changes. The detection limit in buffer for FITC-avidin was determined to be 1.35 nM and 107 cells/ml for S. cerevisiae. For fluorescent microscopy the avidin molecules were labelled with FITC and for the detection of S. cerevisiae the magnetic nanoparticles were additionally functionalised with rhodamine. The binding of the particles to S. cerevisiae and the resulting clustering was also seen by transmission electron microscopy.

  10. Nuclear Reactor/Hydrogen Process Interface Including the HyPEP Model

    SciTech Connect

    Steven R. Sherman

    2007-05-01

    The Nuclear Reactor/Hydrogen Plant interface is the intermediate heat transport loop that will connect a very high temperature gas-cooled nuclear reactor (VHTR) to a thermochemical, high-temperature electrolysis, or hybrid hydrogen production plant. A prototype plant called the Next Generation Nuclear Plant (NGNP) is planned for construction and operation at the Idaho National Laboratory in the 2018-2021 timeframe, and will involve a VHTR, a high-temperature interface, and a hydrogen production plant. The interface is responsible for transporting high-temperature thermal energy from the nuclear reactor to the hydrogen production plant while protecting the nuclear plant from operational disturbances at the hydrogen plant. Development of the interface is occurring under the DOE Nuclear Hydrogen Initiative (NHI) and involves the study, design, and development of high-temperature heat exchangers, heat transport systems, materials, safety, and integrated system models. Research and development work on the system interface began in 2004 and is expected to continue at least until the start of construction of an engineering-scale demonstration plant.

  11. Nonlocal Nuclear Spin Quieting in Quantum Dot Molecules: Optically Induced Extended Two-Electron Spin Coherence Time

    NASA Astrophysics Data System (ADS)

    Chow, Colin M.; Ross, Aaron M.; Kim, Danny; Gammon, Daniel; Bracker, Allan S.; Sham, L. J.; Steel, Duncan G.

    2016-08-01

    We demonstrate the extension of coherence between all four two-electron spin ground states of an InAs quantum dot molecule (QDM) via nonlocal suppression of nuclear spin fluctuations in two vertically stacked quantum dots (QDs), while optically addressing only the top QD transitions. Long coherence times are revealed through dark-state spectroscopy as resulting from nuclear spin locking mediated by the exchange interaction between the QDs. Line shape analysis provides the first measurement of the quieting of the Overhauser field distribution correlating with reduced nuclear spin fluctuations.

  12. Determination of Membrane Protein Distribution on the Nuclear Envelope by Single-Point Single-Molecule FRAP.

    PubMed

    Mudumbi, Krishna C; Yang, Weidong

    2017-09-01

    Nuclear envelope transmembrane proteins (NETs) are synthesized on the endoplasmic reticulum and then transported from the outer nuclear membrane (ONM) to the inner nuclear membrane (INM) in eukaryotic cells. The abnormal distribution of NETs has been associated with many human diseases. However, quantitative determination of the spatial distribution and translocation dynamics of NETs on the ONM and INM is still very limited in currently existing approaches. Here we demonstrate a single-point single-molecule fluorescence recovery after photobleaching (FRAP) microscopy technique that enables quick determination of distribution and translocation rates for NETs in vivo. © 2017 by John Wiley & Sons, Inc. Copyright © 2017 John Wiley & Sons, Inc.

  13. Calculation of Ground State Rotational Populations for Kinetic Gas Homonuclear Diatomic Molecules including Electron-Impact Excitation and Wall Collisions

    SciTech Connect

    David R. Farley

    2010-08-19

    A model has been developed to calculate the ground-state rotational populations of homonuclear diatomic molecules in kinetic gases, including the effects of electron-impact excitation, wall collisions, and gas feed rate. The equations are exact within the accuracy of the cross sections used and of the assumed equilibrating effect of wall collisions. It is found that the inflow of feed gas and equilibrating wall collisions can significantly affect the rotational distribution in competition with non-equilibrating electron-impact effects. The resulting steady-state rotational distributions are generally Boltzmann for N≥3, with a rotational temperature between the wall and feed gas temperatures. The N=0,1,2 rotational level populations depend sensitively on the relative rates of electron-impact excitation versus wall collision and gas feed rates.

  14. Stable, non-destructive immobilization of native nuclear membranes to micro-structured PDMS for single-molecule force spectroscopy.

    PubMed

    Rangl, Martina; Nevo, Reinat; Liashkovich, Ivan; Shahin, Victor; Reich, Ziv; Ebner, Andreas; Hinterdorfer, Peter

    2009-07-13

    In eukaryotic cells the nucleus is separated from the cytoplasm by a double-membraned nuclear envelope (NE). Exchange of molecules between the two compartments is mediated by nuclear pore complexes (NPCs) that are embedded in the NE membranes. The translocation of molecules such as proteins and RNAs through the nuclear membrane is executed by transport shuttling factors (karyopherines). They thereby dock to particular binding sites located all over the NPC, the so-called phenylalanine-glycin nucleoporines (FG Nups). Molecular recognition force spectroscopy (MRFS) allows investigations of the binding at the single-molecule level. Therefore the AFM tip carries a ligand for example, a particular karyopherin whereas the nuclear membrane with its receptors is mounted on a surface. Hence, one of the first requirements to study the nucleocytoplasmatic transport mechanism using MRFS is the development of an optimized membrane preparation that preserves structure and function of the NPCs. In this study we present a stable non-destructive preparation method of Xenopus laevis nuclear envelopes. We use micro-structured polydimethylsiloxane (PDMS) that provides an ideal platform for immobilization and biological integrity due to its elastic, chemical and mechanical properties. It is a solid basis for studying molecular recognition, transport interactions, and translocation processes through the NPC. As a first recognition system we investigate the interaction between an important transport shuttling factor, importin beta, and its binding sites on the NPC, the FG-domains.

  15. Small molecule and peptide-mediated inhibition of Epstein-Barr virus nuclear antigen 1 dimerization

    SciTech Connect

    Kim, Sun Young; Song, Kyung-A; Kieff, Elliott; Kang, Myung-Soo

    2012-07-27

    Highlights: Black-Right-Pointing-Pointer Evidence that targeting EBNA1 dimer, an EBV onco-antigen, can be achievable. Black-Right-Pointing-Pointer A small molecule and a peptide as EBNA1 dimerization inhibitors identified. Black-Right-Pointing-Pointer Both inhibitors associated with EBNA1 and blocked EBNA1 DNA binding activity. Black-Right-Pointing-Pointer Also, prevented its dimerization, and repressed viral gene transcription. -- Abstract: Latent Epstein-Barr virus (EBV) infection is associated with human B cell lymphomas and certain carcinomas. EBV episome persistence, replication, and gene expression are dependent on EBV-encoded nuclear antigen 1 (EBNA1)'s DNA binding domain (DBD)/dimerization domain (DD)-mediated sequence-specific DNA binding activity. Homodimerization of EBNA1 is essential for EBNA1 DNA binding and transactivation. In this study, we characterized a novel small molecule EBNA1 inhibitor EiK1, screened from the previous high throughput screening (HTS). The EiK1 compound specifically inhibited the EBNA1-dependent, OriP-enhanced transcription, but not EBNA1-independent transcription. A Surface Plasmon Resonance Biacore assay revealed that EiK1 associates with EBNA1 amino acid 459-607 DBD/DD. Consistent with the SPR data, in vitro gel shift assays showed that EiK1 suppressed the activity of EBNA1 binding to the cognate familial repeats (FR) sequence, but not control RBP-J{kappa} binding to the J{kappa} site. Subsequently, a cross-linker-mediated in vitro multimerization assay and EBNA1 homodimerization-dependent yeast two-hybrid assay showed that EiK1 significantly inhibited EBNA1 dimerization. In an attempt to identify more highly specific peptide inhibitors, small peptides encompassing the EBNA1 DBD/DD were screened for inhibition of EBNA1 DBD-mediated DNA binding function. The small peptide P85, covering EBNA1 a.a. 560-574, significantly blocked EBNA1 DNA binding activity in vitro, prevented dimerization in vitro and in vivo, associated with

  16. MSTor: A program for calculating partition functions, free energies, enthalpies, entropies, and heat capacities of complex molecules including torsional anharmonicity

    NASA Astrophysics Data System (ADS)

    Zheng, Jingjing; Mielke, Steven L.; Clarkson, Kenneth L.; Truhlar, Donald G.

    2012-08-01

    We present a Fortran program package, MSTor, which calculates partition functions and thermodynamic functions of complex molecules involving multiple torsional motions by the recently proposed MS-T method. This method interpolates between the local harmonic approximation in the low-temperature limit, and the limit of free internal rotation of all torsions at high temperature. The program can also carry out calculations in the multiple-structure local harmonic approximation. The program package also includes six utility codes that can be used as stand-alone programs to calculate reduced moment of inertia matrices by the method of Kilpatrick and Pitzer, to generate conformational structures, to calculate, either analytically or by Monte Carlo sampling, volumes for torsional subdomains defined by Voronoi tessellation of the conformational subspace, to generate template input files, and to calculate one-dimensional torsional partition functions using the torsional eigenvalue summation method. Catalogue identifier: AEMF_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEMF_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 77 434 No. of bytes in distributed program, including test data, etc.: 3 264 737 Distribution format: tar.gz Programming language: Fortran 90, C, and Perl Computer: Itasca (HP Linux cluster, each node has two-socket, quad-core 2.8 GHz Intel Xeon X5560 “Nehalem EP” processors), Calhoun (SGI Altix XE 1300 cluster, each node containing two quad-core 2.66 GHz Intel Xeon “Clovertown”-class processors sharing 16 GB of main memory), Koronis (Altix UV 1000 server with 190 6-core Intel Xeon X7542 “Westmere” processors at 2.66 GHz), Elmo (Sun Fire X4600 Linux cluster with AMD Opteron cores), and Mac Pro (two 2.8 GHz Quad-core Intel Xeon

  17. Nuclear Rocket Test Facility Decommissioning Including Controlled Explosive Demolition of a Neutron-Activated Shield Wall

    SciTech Connect

    Michael Kruzic

    2007-09-01

    Located in Area 25 of the Nevada Test Site, the Test Cell A Facility was used in the 1960s for the testing of nuclear rocket engines, as part of the Nuclear Rocket Development Program. The facility was decontaminated and decommissioned (D&D) in 2005 using the Streamlined Approach For Environmental Restoration (SAFER) process, under the Federal Facilities Agreement and Consent Order (FFACO). Utilities and process piping were verified void of contents, hazardous materials were removed, concrete with removable contamination decontaminated, large sections mechanically demolished, and the remaining five-foot, five-inch thick radiologically-activated reinforced concrete shield wall demolished using open-air controlled explosive demolition (CED). CED of the shield wall was closely monitored and resulted in no radiological exposure or atmospheric release.

  18. Tabulated equation of state for supernova matter including full nuclear ensemble

    SciTech Connect

    Buyukcizmeci, N.; Botvina, A. S.; Mishustin, I. N.

    2014-07-01

    This is an introduction to the tabulated database of stellar matter properties calculated within the framework of the Statistical Model for Supernova Matter (SMSM). The tables present thermodynamical characteristics and nuclear abundances for 31 values of baryon density (10{sup –8} < ρ/ρ{sub 0} < 0.32, ρ{sub 0} = 0.15 fm{sup –3} is the normal nuclear matter density), 35 values of temperature (0.2 MeV < T < 25 MeV), and 28 values of electron-to-baryon ratio (0.02 < Y{sub e} < 0.56). The properties of stellar matter in β equilibrium are also considered. The main ingredients of the SMSM are briefly outlined, and the data structure and content of the tables are explained.

  19. Nuclear winter - Three-dimensional simulations including interactive transport, scavenging, and solar heating of smoke

    NASA Technical Reports Server (NTRS)

    Malone, R. C.; Auer, L. H.; Glatzmaier, G. A.; Wood, M. C.; Toon, O. B.

    1986-01-01

    A reexamination is conducted of the 'nuclear winter' hypothesis with a three-dimensional global model modified to allow for localized injection of smoke, its transport by the simulated winds, its absorption of sunlight, and its removal by model-simulated precipitation. Smoke injected into the troposphere is driven upward by solar heating. The tropopause, initially above the smoke, reforms below the heat smoke layer and separates it from precipitation below. Although much smoke is scavenged while the thermal structure is being altered, the residence time of the remaining smoke is greatly increased. Particularly for July conditions, a longer-lasting 'nuclear winter' effect is observed than was found in earlier modeling studies in which normal tropospheric residence times were assumed. In January the smaller solar flux in the northern hemisphere allows faster removal of smoke than in July. Significant cooling of the northern hemisphere continents is predicted; its dependence on season and injected smoke mass is described.

  20. Supernova equations of state including full nuclear ensemble with in-medium effects

    NASA Astrophysics Data System (ADS)

    Furusawa, Shun; Sumiyoshi, Kohsuke; Yamada, Shoichi; Suzuki, Hideyuki

    2017-01-01

    We construct new equations of state for baryons at sub-nuclear densities for the use in core-collapse supernova simulations. The abundance of various nuclei is obtained together with thermodynamic quantities. The formulation is an extension of the previous model, in which we adopted the relativistic mean field theory with the TM1 parameter set for nucleons, the quantum approach for d, t, h and α as well as the liquid drop model for the other nuclei under the nuclear statistical equilibrium. We reformulate the model of the light nuclei other than d, t, h and α based on the quasi-particle description. Furthermore, we modify the model so that the temperature dependences of surface and shell energies of heavy nuclei could be taken into account. The pasta phases for heavy nuclei and the Pauli- and self-energy shifts for d, t, h and α are taken into account in the same way as in the previous model. We find that nuclear composition is considerably affected by the modifications in this work, whereas thermodynamical quantities are not changed much. In particular, the washout of shell effect has a great impact on the mass distribution above T ∼ 1 MeV. This improvement may have an important effect on the rates of electron captures and coherent neutrino scatterings on nuclei in supernova cores.

  1. Multicomponent Molecular Orbital-Climbing Image-Nudged Elastic Band Method to Analyze Chemical Reactions Including Nuclear Quantum Effect.

    PubMed

    Udagawa, Taro; Suzuki, Kimichi; Tachikawa, Masanori

    2015-10-26

    To analyze the H/D isotope effects on hydrogen transfer reactions in XHCHCHCHY↔XCHCHCHYH (X, Y=O, NH, or CH2 ) including the nuclear quantum effect of proton and deuteron, we propose a multicomponent molecular orbital-climbing image-nudged elastic band (MC_MO-CI-NEB) method. We obtain not only transition state structures but also minimum-energy paths (MEPs) on the MC_MO effective potential energy surface by using MC_MO-CI-NEB method. We find that nuclear quantum effect affects not only stationary-point geometries but also MEPs and electronic structures in the reactions. We clearly demonstrate the importance of including nuclear quantum effects for H/D isotope effect on rate constants (kH /kD ). © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Inhibition of Androgen Receptor Nuclear Localization and Castration-Resistant Prostate Tumor Growth by Pyrroloimidazole-based Small Molecules.

    PubMed

    Masoodi, Khalid Z; Xu, Yadong; Dar, Javid A; Eisermann, Kurtis; Pascal, Laura E; Parrinello, Erica; Ai, Junkui; Johnston, Paul A; Nelson, Joel B; Wipf, Peter; Wang, Zhou

    2017-10-01

    The androgen receptor (AR) is a ligand-dependent transcription factor that controls the expression of androgen-responsive genes. A key step in androgen action, which is amplified in castration-resistant prostate cancer (CRPC), is AR nuclear translocation. Small molecules capable of inhibiting AR nuclear localization could be developed as novel therapeutics for CRPC. We developed a high-throughput screen and identified two structurally-related pyrroloimidazoles that could block AR nuclear localization in CRPC cells. We show that these two small molecules, 3-(4-ethoxyphenyl)-6,7-dihydro-5H-pyrrolo[1,2-a]imidazole (EPPI) and 3-(4-chlorophenyl)-6,7-dihydro-5H-pyrrolo[1,2-a]imidazole (CPPI) can inhibit the nuclear localization and transcriptional activity of AR and reduce the proliferation of AR-positive but not AR-negative prostate cancer cell lines. EPPI and CPPI did not inhibit nuclear localization of the glucocorticoid receptor or the estrogen receptor, suggesting they selectively target AR. In LNCaP tumor xenografts, CPPI inhibited the proliferation of relapsed LNCaP tumors. These findings suggest that EPPI and CPPI could serve as lead structures for the development of therapeutic agents for CRPC. Mol Cancer Ther; 16(10); 2120-9. ©2017 AACR. ©2017 American Association for Cancer Research.

  3. Discovery of a Novel, Isothiazolonaphthoquinone-Based Small Molecule Activator of FOXO Nuclear-Cytoplasmic Shuttling

    PubMed Central

    Cautain, Bastien; Castillo, Francisco; Musso, Loana; Ferreira, Bibiana I.; de Pedro, Nuria; Rodriguez Quesada, Lorena; Machado, Susana; Vicente, Francisca; Dallavalle, Sabrina

    2016-01-01

    FOXO factors are tumour suppressor proteins commonly inactivated in human tumours by posttranslational modifications. Furthermore, genetic variation within the FOXO3a gene is consistently associated with human longevity. Therefore, the pharmacological activation of FOXO proteins is considered as an attractive therapeutic approach to treat cancer and age-related diseases. In order to identify agents capable of activating FOXOs, we tested a collection of small chemical compounds using image-based high content screening technology. Here, we report the discovery of LOM612 (compound 1a), a newly synthesized isothiazolonaphthoquinone as a potent FOXO relocator. Compound 1a induces nuclear translocation of a FOXO3a reporter protein as well as endogenous FOXO3a and FOXO1 in U2OS cells in a dose-dependent manner. This activity does not affect the subcellular localization of other cellular proteins including NFkB or inhibit CRM1-mediated nuclear export. Furthermore, compound 1a shows a potent antiproliferative effect in human cancer cell lines. PMID:27936162

  4. Dynamic two-center interference in high-order harmonic generation from molecules with attosecond nuclear motion.

    PubMed

    Baker, S; Robinson, J S; Lein, M; Chirilă, C C; Torres, R; Bandulet, H C; Comtois, D; Kieffer, J C; Villeneuve, D M; Tisch, J W G; Marangos, J P

    2008-08-01

    We report a new dynamic two-center interference effect in high-harmonic generation from H2, in which the attosecond nuclear motion of H2+ initiated at ionization causes interference to be observed at lower harmonic orders than would be the case for static nuclei. To enable this measurement we utilize a recently developed technique for probing the attosecond nuclear dynamics of small molecules. The experimental results are reproduced by a theoretical analysis based upon the strong-field approximation which incorporates the temporally dependent two-center interference term.

  5. A new equation of state for core-collapse supernovae based on realistic nuclear forces and including a full nuclear ensemble

    NASA Astrophysics Data System (ADS)

    Furusawa, S.; Togashi, H.; Nagakura, H.; Sumiyoshi, K.; Yamada, S.; Suzuki, H.; Takano, M.

    2017-09-01

    We have constructed a nuclear equation of state (EOS) that includes a full nuclear ensemble for use in core-collapse supernova simulations. It is based on the EOS for uniform nuclear matter that two of the authors derived recently, applying a variational method to realistic two- and three-body nuclear forces. We have extended the liquid drop model of heavy nuclei, utilizing the mass formula that accounts for the dependences of bulk, surface, Coulomb and shell energies on density and/or temperature. As for light nuclei, we employ a quantum-theoretical mass evaluation, which incorporates the Pauli- and self-energy shifts. In addition to realistic nuclear forces, the inclusion of in-medium effects on the full ensemble of nuclei makes the new EOS one of the most realistic EOSs, which covers a wide range of density, temperature and proton fraction that supernova simulations normally encounter. We make comparisons with the FYSS EOS, which is based on the same formulation for the nuclear ensemble but adopts the relativistic mean field theory with the TM1 parameter set for uniform nuclear matter. The new EOS is softer than the FYSS EOS around and above nuclear saturation densities. We find that neutron-rich nuclei with small mass numbers are more abundant in the new EOS than in the FYSS EOS because of the larger saturation densities and smaller symmetry energy of nuclei in the former. We apply the two EOSs to 1D supernova simulations and find that the new EOS gives lower electron fractions and higher temperatures in the collapse phase owing to the smaller symmetry energy. As a result, the inner core has smaller masses for the new EOS. It is more compact, on the other hand, due to the softness of the new EOS and bounces at higher densities. It turns out that the shock wave generated by core bounce is a bit stronger initially in the simulation with the new EOS. The ensuing outward propagations of the shock wave in the outer core are very similar in the two simulations, which

  6. Nuclear-wave-packet dynamics mapped out by two-center interference in the HeH2+ molecule

    NASA Astrophysics Data System (ADS)

    Schüler, M.; Pavlyukh, Y.; Berakdar, J.

    2014-06-01

    Photoemission from diatomic molecules closely resembles the Young-type double-slit experiment where each of the two atomic sites represents a coherent emission source. When the photoelectron wavelength becomes commensurate with the effective interatomic distance, the resulting spatial interference gives rise to oscillations in the photoionization total and differential cross sections. This phenomenon provides detailed information on the molecular geometry, a fact that can be utilized for probing the nuclear dynamics triggered by the interaction with a laser field. We demonstrate how this coherent wave-packet evolution can be traced by observing the photoelectron angular distribution. Based on ab initio scattering calculations we perform a proof-of-principle reconstruction of the nuclear-wave-packet evolution in the HeH2+ molecule.

  7. Hybrid approach for including electronic and nuclear quantum effects in molecular dynamics simulations of hydrogen transfer reactions in enzymes

    NASA Astrophysics Data System (ADS)

    Billeter, Salomon R.; Webb, Simon P.; Iordanov, Tzvetelin; Agarwal, Pratul K.; Hammes-Schiffer, Sharon

    2001-04-01

    A hybrid approach for simulating proton and hydride transfer reactions in enzymes is presented. The electronic quantum effects are incorporated with an empirical valence bond approach. The nuclear quantum effects of the transferring hydrogen are included with a mixed quantum/classical molecular dynamics method in which the hydrogen nucleus is described as a multidimensional vibrational wave function. The free energy profiles are obtained as functions of a collective reaction coordinate. A perturbation formula is derived to incorporate the vibrationally adiabatic nuclear quantum effects into the free energy profiles. The dynamical effects are studied with the molecular dynamics with quantum transitions (MDQT) surface hopping method, which incorporates nonadiabatic transitions among the adiabatic hydrogen vibrational states. The MDQT method is combined with a reactive flux approach to calculate the transmission coefficient and to investigate the real-time dynamics of reactive trajectories. This hybrid approach includes nuclear quantum effects such as zero point energy, hydrogen tunneling, and excited vibrational states, as well as the dynamics of the complete enzyme and solvent. The nuclear quantum effects are incorporated during the generation of the free energy profiles and dynamical trajectories rather than subsequently added as corrections. Moreover, this methodology provides detailed mechanistic information at the molecular level and allows the calculation of rates and kinetic isotope effects. An initial application of this approach to the enzyme liver alcohol dehydrogenase is also presented.

  8. The development of a single molecule fluorescence standard and its application in estimating the stoichiometry of the nuclear pore complex.

    PubMed

    Tie, Hieng Chiong; Madugula, Viswanadh; Lu, Lei

    2016-09-30

    We report here an image-based method to quantify the stoichiometry of diffraction-limited sub-cellular protein complexes in vivo under spinning disk confocal microscopy. A GFP single molecule fluorescence standard was first established by immobilizing His-tagged GFP molecules onto the glass surface via nickel nitrilotriacetic acid functionalized polyethylene glycol. When endogenous nucleoporins were knocked down and replaced by the exogenously expressed and knockdown-resistant GFP-nucleoporins, the stoichiometry of the nucleoporin was estimated by the ratio of its fluorescence intensity to that of the GFP single molecules. Our measured stoichiometry of Nup35, Nup93, Nup133 and Nup88 is 23, 18, 14 and 9 and there are possibly16 copies of Nup107-160 complex per nuclear pore complex.

  9. Modeling the Emission Spectra of Organic Molecules: A Competition between Franck-Condon and Nuclear Ensemble Methods.

    PubMed

    de Sousa, Leonardo Evaristo; Ribeiro, Luiz Antonio; Fonseca, Antonio Luciano de Almeida; da Silva Filho, Demétrio Antonio

    2016-07-14

    The emission spectra of flexible and rigid organic molecules are theoretically investigated in the framework of the Franck-Condon (FC) and nuclear ensemble (NE) approaches, both of which rely on results from density functional theory but differ in the way vibrational contributions are taken into account. Our findings show that the emission spectra obtained using the NE approach are in better agreement with experiment than the ones produced by FC calculations considering both rigid and flexible molecules. Surprisingly, the description of a suitable balance between the vibronic progression and the emission spectra envelope shows dependency on the initial sampling for the NE calculations which must be judiciously selected. Our results intend to provide guidance for a better theoretical description of light emission properties of organic molecules with applications in organic electronic devices.

  10. Differential two-body compound nuclear cross section, including the width-fluctuation corrections

    SciTech Connect

    Brown, D.; Herman, M.

    2014-09-02

    We figure out the compound angular differential cross sections, following mainly Fröbrich and Lipperheide, but with the angular momentum couplings that make sense for optical model work. We include the width-fluctuation correction along with calculations.

  11. Network of nuclear receptor ligands in multiple sclerosis: Common pathways and interactions of sex-steroids, corticosteroids and vitamin D3-derived molecules.

    PubMed

    Rolf, Linda; Damoiseaux, Jan; Hupperts, Raymond; Huitinga, Inge; Smolders, Joost

    2016-09-01

    Sex-steroids, corticosteroids and vitamin D3-derived molecules have all been subject to experimental studies and clinical trials in a plethora of autoimmune diseases. These molecules are all derived from cholesterol metabolites and are ligands for nuclear receptors. Ligation of these receptors results in direct regulation of multiple gene transcription involved in general homeostatic and adaptation networks, including the immune system. Indeed, the distinct ligands affect the function of both myeloid and lymphoid cells, eventually resulting in a less pro-inflammatory immune response which is considered beneficial in autoimmune diseases. Next to the immune system, also the central nervous system is prone to regulation by these nuclear receptor ligands. Understanding of the intricate interactions between sex-steroids, corticosteroids and vitamin D3 metabolites, on the one hand, and the immune and central nervous system, on the other hand, may reveal novel approaches to utilize these nuclear receptor ligands to full extent as putative treatments in multiple sclerosis, the prototypic immune-driven disease of the central nervous system. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Estimation of full moment tensors, including uncertainties, for earthquakes, volcanic events, and nuclear explosions

    NASA Astrophysics Data System (ADS)

    Alvizuri, Celso R.

    rather the confidence, is then given by the 'confidence curve' P( V), where P(V) is the probability that the true moment tensor for the event lies within the neighborhood of M that has fractional volume V. The area under the confidence curve provides a single, abbreviated 'confidence parameter' for M0. We apply the method to data from events in different regions and tectonic settings: 63 small (M w 4) earthquakes in the southern Alaska subduction zone, and 12 earthquakes and 17 nuclear explosions at the Nevada Test Site. Characterization of moment tensor uncertainties puts us in better position to discriminate among moment tensor source types and to assign physical processes to the events.

  13. An independent atom model description of ion-molecule collisions including geometric screening corrections: application to biomolecules

    NASA Astrophysics Data System (ADS)

    Lüdde, H. J.; Achenbach, A.; Kalkbrenner, T.; Jankowiak, H. C.; Kirchner, T.

    2016-09-01

    Recently, we proposed to calculate electron removal cross sections for ion-molecule collisions in an independent atom model that accounts for geometric screening corrections. The correction coefficients are obtained from using a pixel counting method (PCM) for the exact calculation of the effective cross sectional area that emerges when the molecular cross section is pictured as a structure of (overlapping) atomic cross sections. This structure varies with the relative orientation of the molecule with respect to the projectile beam direction and, accordingly, orientation-independent total cross sections are obtained from averaging the pixel count over many orientations. In this contribution, we apply the PCM to proton collisions from amino acids and DNA and RNA nucleobases. The strength of the screening effect is analyzed by comparing the PCM results with Bragg additivity rule cross sections and with experimental data where available. Work supported by NSERC, Canada.

  14. Release and recovery of guest molecules during the reversible borate gel formation of guest-included macrocyclic boronic esters.

    PubMed

    Ito, Suguru; Takata, Hisatsugu; Ono, Kosuke; Iwasawa, Nobuharu

    2013-10-11

    Borate gel formation from guest-encapsulated macrocyclic boronic esters was realized by the addition of a diamine to the suspension of the boronic esters in various organic solvents, which triggered the release of the guest compounds. The guest molecules could be recovered from the borate gel by addition of an acid to remove the diamine, which facilitated the reconstruction of the initial guest-encapsulated macrocyclic boronic esters.

  15. An expanded Metrosideros (Myrtaceae) to include Carpolepis and Tepualia based on nuclear genes

    USDA-ARS?s Scientific Manuscript database

    The genus Metrosideros (Myrtaceae) comprises 50-60 species, found largely across the Pacific Islands. The relationships within this genus, including the circumscriptions of the subgenera Mearnsia and Metrosideros and their relationships with the other members of the tribe Metrosidereae, namely the N...

  16. An Intramolecular Silylene Borane Capable of Facile Activation of Small Molecules, Including Metal-Free Dehydrogenation of Water.

    PubMed

    Mo, Zhenbo; Szilvási, Tibor; Zhou, Yu-Peng; Yao, Shenglai; Driess, Matthias

    2017-02-27

    The first single-component N-heterocyclic silylene borane 1 (LSi-R-BMes2 ; L=PhC(N(t) Bu)2 ; R=1,12-xanthendiyl spacer; Mes=2,4,6-Me3 C6 H2 ), acting as a frustrated Lewis pair (FLP) in small-molecule activation, can be synthesized in 65 % yields. Its HOMO is largely localized at the silicon(II) atom and the LUMO has mainly boron 2p character. In small-molecule activation 1 allows access to the intramolecular silanone-borane 3 featuring a Si=O→B interaction through reaction with O2 , N2 O, or CO2 , and formation of silanethione borane 4 from reaction with S8 . The Si(II) center in 1 undergoes immediate hydrogenation if exposed to H2 at 1 atm pressure in benzene, affording the silane borane 5-H2 , L(H2 )Si-R-BMes2 . Remarkably, no H2 activation occurs if the single silylene LSiPh and Mes3 B intermolecularly separated are exposed to dihydrogen. Unexpectedly, the pre-organized Si-B separation in 1 enables a metal-free dehydrogenation of H2 O to give the silanone-borane 3 as reactive intermediate.

  17. Ultrafast x-ray-induced nuclear dynamics in diatomic molecules using femtosecond x-ray-pump-x-ray-probe spectroscopy

    NASA Astrophysics Data System (ADS)

    Lehmann, C. S.; Picón, A.; Bostedt, C.; Rudenko, A.; Marinelli, A.; Moonshiram, D.; Osipov, T.; Rolles, D.; Berrah, N.; Bomme, C.; Bucher, M.; Doumy, G.; Erk, B.; Ferguson, K. R.; Gorkhover, T.; Ho, P. J.; Kanter, E. P.; Krässig, B.; Krzywinski, J.; Lutman, A. A.; March, A. M.; Ray, D.; Young, L.; Pratt, S. T.; Southworth, S. H.

    2016-07-01

    The capability of generating two intense, femtosecond x-ray pulses with a controlled time delay opens the possibility of performing time-resolved experiments for x-ray-induced phenomena. We have applied this capability to study the photoinduced dynamics in diatomic molecules. In molecules composed of low-Z elements, K -shell ionization creates a core-hole state in which the main decay mode is an Auger process involving two electrons in the valence shell. After Auger decay, the nuclear wave packets of the transient two-valence-hole states continue evolving on the femtosecond time scale, leading either to separated atomic ions or long-lived quasibound states. By using an x-ray pump and an x-ray probe pulse tuned above the K -shell ionization threshold of the nitrogen molecule, we are able to observe ion dissociation in progress by measuring the time-dependent kinetic energy releases of different breakup channels. We simulated the measurements on N2 with a molecular dynamics model that accounts for K -shell ionization, Auger decay, and the time evolution of the nuclear wave packets. In addition to explaining the time-dependent feature in the measured kinetic energy release distributions from the dissociative states, the simulation also reveals the contributions of quasibound states.

  18. Unravelling the molecular structure and packing of a planar molecule by combining nuclear magnetic resonance and scanning tunneling microscopy.

    PubMed

    Sáfar, Gustavo A M; Malachias, Angelo; Magalhães-Paniago, Rogério; Martins, Dayse C S; Idemori, Ynara M

    2013-12-21

    The determination of the molecular structure of a porphyrin is achieved by using nuclear magnetic resonance (NMR) and scanning tunneling microscopy (STM) techniques. Since macroscopic crystals cannot be obtained in this system, this combination of techniques is crucial to solve the molecular structure without the need for X-ray crystallography. For this purpose, previous knowledge of the flatness of the reagent molecules (a porphyrin and its functionalizing group, a naphthalimide) and the resulting molecular structure obtained by a force-field simulation are used. The exponents of the I-V curves obtained by scanning tunneling spectroscopy (STS) allow us to check whether the thickness of the film of molecules is greater than a monolayer, even when there is no direct access to the exposed surface of the metal substrate. Photoluminescence (PL), optical absorption, infrared (IR) reflectance and solubility tests are used to confirm the results obtained here with this NMR/STM/STS combination.

  19. Nuclear Receptors: Small Molecule Sensors that Coordinate Growth, Metabolism and Reproduction.

    PubMed

    Pardee, Keith; Necakov, Aleksandar S; Krause, Henry

    2011-01-01

    One of the largest groups of metazoan transcription factors (TFs), the Nuclear Receptor superfamily, regulates genes required for virtually all aspects of development, reproduction and metabolism. Together, these master regulators can be thought of as a fundamental operating system for metazoan life. Their most distinguishing feature is a structurally conserved domain that acts as a switch, powered by the presence of small diffusible ligands. This ligand-responsive regulation has allowed the Nuclear Receptors to help their hosts adapt to a wide variety of physiological niches and roles, making them one of the most evolutionarily successful TF families. Originally discovered as receptors for steroid hormones, the Nuclear Receptor field has grown to encompass much more than traditional endocrinology. For example, recent work has highlighted the role of Nuclear Receptors as major regulators of metabolism and biological clocks. By monitoring endogenous metabolites and absorbed xenobiotics, these receptors also coordinate rapid, system-wide responses to changing metabolic and environmental states. While many new Nuclear Receptor ligands have been discovered in the past couple of decades, approximately half of the 48 human receptors are still orphans, with a significantly higher percentage of orphans in other organisms. The discovery of new ligands has led to the elucidation of new regulatory mechanisms, target genes, pathways and functions. This review will highlight both the common as well as newly emerging traits and functions that characterize this particularly unique and important TF family.

  20. Parity nonconservation contribution to the nuclear magnetic resonance shielding constants of chiral molecules: a four-component relativistic study.

    PubMed

    Bast, Radovan; Schwerdtfeger, Peter; Saue, Trond

    2006-08-14

    A systematic four-component relativistic study of the parity nonconservation (PNC) contribution to the (isotropic) NMR shielding constants of chiral molecules is presented for the P enantiomers of the series H(2)X(2) (X=(17)O,(33)S,(77)Se,(125)Te,(209)Po). The PNC contributions are obtained within a linear response approach at the Hartree-Fock level. A careful design of the basis sets is necessary. The four-component relativistic results based on the Dirac-Coulomb Hamiltonian are compared with the nonrelativistic Levy-Leblond results and those obtained by the spin-free modified Dirac Hamiltonian. The calculations confirm the nonrelativistic scaling law Z(2.4) of the PNC contribution with respect to nuclear charge Z. However, the calculations also show that the overall scaling is significantly modified by relativistic effects. The scalar relativistic effect scales as Z(4.7) for the selected set of molecules, whereas the spin-orbit effect, of opposite sign, scales better than Z(6) and completely dominates the PNC contribution for the heaviest elements. This opens up the intriguing possibility of the experimental observation of PNC effects on NMR parameters of molecules containing heavy atoms. The presented formalism is expected to be valuable in assisting the search for suitable candidate molecules.

  1. Molecular and structural characterization of dissolved organic matter from the deep ocean by FTICR-MS, including hydrophilic nitrogenous organic molecules

    USGS Publications Warehouse

    Reemtsma, T.; These, A.; Linscheid, M.; Leenheer, J.; Spitzy, A.

    2008-01-01

    Dissolved organic matter isolated from the deep Atlantic Ocean and fractionated into a so-called hydrophobic (HPO) fraction and a very hydrophilic (HPI) fraction was analyzed for the first time by Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS) to resolve the molecular species, to determine their exact masses, and to calculate their molecular formulas. The elemental composition of about 300 molecules was identified. Those in the HPO fraction (14C age of 5100 year) are very similar to much younger freshwater fulvic acids, but less aromatic and more oxygenated molecules are more frequent. This trend continues toward the HPI fraction and may indicate biotic and abiotic aging processes that this material experienced since its primary production thousands of years ago. In the HPI fraction series of nitrogenous molecules containing one, two, or three nitrogens were identified by FTICR-MS. Product ion spectra of the nitrogenous molecules suggest that the nitrogen atoms in these molecules are included in the (alicyclic) backbone of these molecules, possibly in reduced form. These mass spectrometric data suggest that a large set of stable fulvic acids is ubiquitous in all aquatic compartments. Although sources may differ, their actual composition and structure appears to be quite similar and largely independent from their source, because they are the remainder of intensive oxidative degradation processes. ?? 2008 American Chemical Society.

  2. Microhydration of caesium compounds: Cs, CsOH, CsI and Cs₂I₂ complexes with one to three H₂O molecules of nuclear safety interest.

    PubMed

    Sudolská, Mária; Cantrel, Laurent; Cernušák, Ivan

    2014-04-01

    Structure and thermodynamic properties (standard enthalpies of formation and Gibbs free energies) of hydrated caesium species of nuclear safety interest, Cs, CsOH, CsI and its dimer Cs₂I₂, with one up to three water molecules, are calculated to assess their possible existence in severe accident occurring to a pressurized water reactor. The calculations were performed using the coupled cluster theory including single, double and non-iterative triple substitutions (CCSD(T)) in conjunction with the basis sets (ANO-RCC) developed for scalar relativistic calculations. The second-order spin-free Douglas-Kroll-Hess Hamiltonian was used to account for the scalar relativistic effects. Thermodynamic properties obtained by these correlated ab initio calculations (entropies and thermal capacities at constant pressure as a function of temperature) are used in nuclear accident simulations using ASTEC/SOPHAEROS software. Interaction energies, standard enthalpies and Gibbs free energies of successive water molecules addition determine the ordering of the complexes. CsOH forms the most hydrated stable complexes followed by CsI, Cs₂I₂, and Cs. CsOH still exists in steam atmosphere even at quite high temperature, up to around 1100 K.

  3. Nuclear lamina genetic variants, including a truncated LAP2, in twins and siblings with nonalcoholic fatty liver disease.

    PubMed

    Brady, Graham F; Kwan, Raymond; Ulintz, Peter J; Nguyen, Phirum; Bassirian, Shirin; Basrur, Venkatesha; Nesvizhskii, Alexey I; Loomba, Rohit; Omary, M Bishr

    2017-09-13

    Nonalcoholic fatty liver disease (NAFLD) is becoming the major chronic liver disease in many countries. Its pathogenesis is multifactorial but twin and familial studies indicate significant heritability, which is not fully explained by currently-known genetic susceptibility loci. Notably, mutations in genes encoding nuclear lamina proteins, including lamins, cause lipodystrophy syndromes that include NAFLD. We hypothesized that variants in lamina-associated proteins predispose to NAFLD and used a candidate gene-sequencing approach to test for variants in 10 nuclear lamina-related genes in a cohort of 37 twin and sibling pairs: 21 individuals with, and 53 without, NAFLD. Twelve heterozygous sequence variants were identified in four lamina-related genes (ZMPSTE24/TMPO/SREBF1/SREBF2). The majority of NAFLD patients (>90%) had at least one variant, compared to <40% of controls (P<0.0001). When only insertions/deletions and changes in conserved residues were considered, the difference between the groups was similarly striking (>80% versus <25%; P<0.0001). Presence of a lamina variant segregated with NAFLD independent of the PNPLA3 I148M polymorphism. Several variants were found in TMPO, which encodes the lamina-associated polypeptide-2 (LAP2) that has not previously been associated with liver disease. One of these, a frameshift insertion that generates truncated LAP2, abrogated lamin-LAP2 binding, caused LAP2 mislocalization, altered endogenous lamin distribution, increased lipid droplet accumulation after oleic acid treatment in transfected cells, and led to cytoplasmic association with the ubiquitin-binding protein p62/SQSTM1. Novel variants in nuclear lamina-related genes were identified in a cohort of twins and siblings with NAFLD. One novel variant, which results in a truncated LAP2 protein and a dramatic phenotype in cell culture, represents the first association of TMPO/LAP2 variants with NAFLD and underscores the potential importance of the nuclear lamina in

  4. Enzymatic repair of selected cross-linked homoduplex molecules enhances nuclear gene rescue from Pompeii and Herculaneum remains

    PubMed Central

    Di Bernardo, Giovanni; Del Gaudio, Stefania; Cammarota, Marcella; Galderisi, Umberto; Cascino, Antonino; Cipollaro, Marilena

    2002-01-01

    Ancient DNA (aDNA) samples extracted from the bone remains of six equids buried by the Vesuvius eruption in 79 AD were investigated to test pre-amplification and enzymatic repair procedures designed to enhance the rescue of nuclear genes. The extracts, which proved all positive for Equidae mtDNA amplification, proved positive only four times out of 18 when tested for single-copy Equidae nuclear genes (ɛ globin, p53 and γ interferon). Pre-amplification did not change the number of retrieved aDNA sequences but 10 times out of 14 enzymatic repair restored the amplifiability of the genes analysed, proving that repair increases the rate of successful rescue from 22 to αλµοστ 80%. These findings support the hypothesis that some of these cross-linked aDNA molecules, which are not completely separated when DNA is extracted under denaturing conditions, become homoduplex substrates for Pol I and/or T4 ligase action upon renaturation. aDNA authenticity is proved by the homology of the nucleotide sequences of loci tested to the corresponding modern Equidae sequences. Data also indicate that cross-linked homoduplex molecules selected by denaturation of the extract are repaired without any chimera formation. The general features of aDNA amplification with and without denaturation and enzymatic repair are discussed. PMID:11842122

  5. Enzymatic repair of selected cross-linked homoduplex molecules enhances nuclear gene rescue from Pompeii and Herculaneum remains.

    PubMed

    Di Bernardo, Giovanni; Del Gaudio, Stefania; Cammarota, Marcella; Galderisi, Umberto; Cascino, Antonino; Cipollaro, Marilena

    2002-02-15

    Ancient DNA (aDNA) samples extracted from the bone remains of six equids buried by the Vesuvius eruption in 79 AD were investigated to test pre-amplification and enzymatic repair procedures designed to enhance the rescue of nuclear genes. The extracts, which proved all positive for Equidae mtDNA amplification, proved positive only four times out of 18 when tested for single-copy Equidae nuclear genes (epsilon globin, p53 and gamma interferon). Pre-amplification did not change the number of retrieved aDNA sequences but 10 times out of 14 enzymatic repair restored the amplifiability of the genes analysed, proving that repair increases the rate of successful rescue from 22 to alpha(lambda)mu(omicron)sigma(tau) 80%. These findings support the hypothesis that some of these cross-linked aDNA molecules, which are not completely separated when DNA is extracted under denaturing conditions, become homoduplex substrates for Pol I and/or T4 ligase action upon renaturation. aDNA authenticity is proved by the homology of the nucleotide sequences of loci tested to the corresponding modern Equidae sequences. Data also indicate that cross-linked homoduplex molecules selected by denaturation of the extract are repaired without any chimera formation. The general features of aDNA amplification with and without denaturation and enzymatic repair are discussed.

  6. Nuclear quadrupole moment-induced Cotton-Mouton effect in molecules

    SciTech Connect

    Fu, Li-juan E-mail: juha.vaara@iki.fi; Vaara, Juha E-mail: juha.vaara@iki.fi

    2014-01-14

    Nuclear magneto-optic effects could make important contributions to novel, high-sensitivity, and high-resolution spectroscopic and imaging methods that provide nuclear site-specific structural and dynamic information on molecular and materials systems. Here we present a first-principles electronic structure formulation of nuclear quadrupole moment-induced Cotton-Mouton effect in terms of response theory, as well as ab initio and density-functional theory calculations of this phenomenon for a series of molecular liquids: H{sub 2}O, CH{sub 3}NO{sub 2}, CH{sub 3}CH{sub 2}OH, C{sub 6}H{sub 6}, C{sub 6}H{sub 12} (cyclohexane), HI, XeF{sub 2}, WF{sub 5}Cl, and Pt(C{sub 2}dtp){sub 2}. The roles of basis-set convergence, electron correlation, and relativistic effects are discussed. The estimated order of magnitude of the overall ellipticities induced to linearly polarized light is 10{sup −3}–10{sup −7} rad/(M cm) for fully spin polarized nuclei. The cases with the largest presently obtained ellipticities should be detectable with modern instrumentation in the Voigt magneto-optic setup, particularly for the heavy nuclei.

  7. Nuclear Spin Locking and Extended Two-Electron Spin Decoherence Time in an InAs Quantum Dot Molecule

    NASA Astrophysics Data System (ADS)

    Chow, Colin; Ross, Aaron; Steel, Duncan; Sham, L. J.; Bracker, Allan; Gammon, Daniel

    2015-03-01

    The spin eigenstates for two electrons confined in a self-assembled InAs quantum dot molecule (QDM) consist of the spin singlet state, S, with J = 0 and the triplet states T-, T0 and T+, with J = 1. When a transverse magnetic field (Voigt geometry) is applied, the two-electron system can be initialized to the different states with appropriate laser excitation. Under the excitation of a weak probe laser, non-Lorentzian lineshapes are obtained when the system is initialized to either T- or T+, where T- results in a ``resonance locking'' lineshape while T+ gives a ``resonance avoiding '' lineshape: two different manifestations of hysteresis showing the importance of memory in the system. These observations signify dynamic nuclear spin polarization (DNSP) arising from a feedback mechanism involving hyperfine interaction between lattice nuclei and delocalized electron spins, and Overhauser shift due to nuclear spin polarization. Using pump configurations that generate coherent population trapping, the isolation of the electron spin from the optical excitation shows the stabilization of the nuclear spin ensemble. The dark-state lineshape measures the lengthened electron spin decoherence time, from 1 ns to 1 μs. Our detailed spectra highlight the potential of QDM for realizing a two-qubit gate. This work is supported by NSF, ARO, AFOSR, DARPA, and ONR.

  8. Probing strong-field electron-nuclear dynamics of polyatomic molecules using proton motion

    SciTech Connect

    Markevitch, Alexei N.; Smith, Stanley M.; Levis, Robert J.; Romanov, Dmitri A.

    2007-05-15

    Proton ejection during Coulomb explosion is studied for several structure-related organic molecules (anthracene, anthraquinone, and octahydroanthracene) subjected to 800 nm, 60 fs laser pulses at intensities from 0.50 to 4.0x10{sup 14} W cm{sup -2}. The proton kinetic energy distributions are found to be markedly structure specific. The distributions are bimodal for anthracene and octahydroanthracene and trimodal for anthraquinone. Maximum (cutoff) energies of the distributions range from 50 eV for anthracene to 83 eV for anthraquinone. The low-energy mode ({approx}10 eV) is most pronounced in octahydroanthracene. The dependence of the characteristic features of the distributions on the laser intensity provides insights into molecular specificity of such strong-field phenomena as (i) nonadiabatic charge localization and (ii) field-mediated restructuring of polyatomic molecules polarized by a strong laser field.

  9. Electron-Nuclear Coupling through Autoionizing States after Strong-Field Excitation of H2 Molecules

    NASA Astrophysics Data System (ADS)

    Mi, Yonghao; Camus, Nicolas; Fechner, Lutz; Laux, Martin; Moshammer, Robert; Pfeifer, Thomas

    2017-05-01

    Channel-selective electron emission from strong-field photoionization of H2 molecules is experimentally investigated by using ultrashort laser pulses and a reaction microscope. The electron momenta and energy spectra in coincidence with bound and dissociative ionization channels are compared. Surprisingly, we observed an enhancement of the photoelectron yield in the low-energy region for the bound ionization channel. By further investigation of asymmetrical electron emission using two-color laser pulses, this enhancement is understood as the population of the autoionizing states of H2 molecules in which vibrational energy is transferred to electronic energy. This general mechanism provides access to the vibrational-state distribution of molecular ions produced in a strong-field interaction.

  10. Electron-Nuclear Coupling through Autoionizing States after Strong-Field Excitation of H_{2} Molecules.

    PubMed

    Mi, Yonghao; Camus, Nicolas; Fechner, Lutz; Laux, Martin; Moshammer, Robert; Pfeifer, Thomas

    2017-05-05

    Channel-selective electron emission from strong-field photoionization of H_{2} molecules is experimentally investigated by using ultrashort laser pulses and a reaction microscope. The electron momenta and energy spectra in coincidence with bound and dissociative ionization channels are compared. Surprisingly, we observed an enhancement of the photoelectron yield in the low-energy region for the bound ionization channel. By further investigation of asymmetrical electron emission using two-color laser pulses, this enhancement is understood as the population of the autoionizing states of H_{2} molecules in which vibrational energy is transferred to electronic energy. This general mechanism provides access to the vibrational-state distribution of molecular ions produced in a strong-field interaction.

  11. Nuclear Overhauser effect as a probe of molecular structure, dynamics and order of axially reorienting molecules in membranes.

    PubMed

    Davis, James H; Komljenović, Ivana

    2016-02-01

    The location, orientation, order and dynamics of cholesterol in model membranes have been well characterized, therefore cholesterol is an ideal molecule for developing new methods for studying structured molecules undergoing rapid axially symmetric reorientation. The use of (13)C filtering via short contact cross polarization transfer to (1)H allows the recovery of the weak cholesterol (1)H magic angle spinning NMR signals from beneath the strong phospholipid background in bicelles composed of chain perdeuterated dimyristoyl phosphatidylcholine/dicaproyl phosphatidylcholine/[3,4-(13)C]-cholesterol. Measurements of the nuclear Overhauser enhancement for (1)H nuclei located in the first ring of cholesterol are interpreted in terms of a simple two motion model consisting of axial reorientation, with a correlation time τ∥, and a slower reorientation of the diffusion axis relative to the bilayer normal, with correlation time τ⊥. This approach can be extended to other molecules which undergo rapid axial reorientation such as small membrane associated peptides. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. Ultrafast Charge Rearrangement and Nuclear Dynamics upon Inner-Shell Multiple Ionization of Small Polyatomic Molecules

    NASA Astrophysics Data System (ADS)

    Erk, B.; Rolles, D.; Foucar, L.; Rudek, B.; Epp, S. W.; Cryle, M.; Bostedt, C.; Schorb, S.; Bozek, J.; Rouzee, A.; Hundertmark, A.; Marchenko, T.; Simon, M.; Filsinger, F.; Christensen, L.; De, S.; Trippel, S.; Küpper, J.; Stapelfeldt, H.; Wada, S.; Ueda, K.; Swiggers, M.; Messerschmidt, M.; Schröter, C. D.; Moshammer, R.; Schlichting, I.; Ullrich, J.; Rudenko, A.

    2013-02-01

    Ionization and fragmentation of methylselenol (CH3SeH) molecules by intense (>1017W/cm2) 5 fs x-ray pulses (ℏω=2keV) are studied by coincident ion momentum spectroscopy. We contrast the measured charge state distribution with data on atomic Kr, determine kinetic energies of resulting ionic fragments, and compare them to the outcome of a Coulomb explosion model. We find signatures of ultrafast charge redistribution from the inner-shell ionized Se atom to its molecular partners, and observe significant displacement of the atomic constituents in the course of multiple ionization.

  13. Ultrafast charge rearrangement and nuclear dynamics upon inner-shell multiple ionization of small polyatomic molecules.

    PubMed

    Erk, B; Rolles, D; Foucar, L; Rudek, B; Epp, S W; Cryle, M; Bostedt, C; Schorb, S; Bozek, J; Rouzee, A; Hundertmark, A; Marchenko, T; Simon, M; Filsinger, F; Christensen, L; De, S; Trippel, S; Küpper, J; Stapelfeldt, H; Wada, S; Ueda, K; Swiggers, M; Messerschmidt, M; Schröter, C D; Moshammer, R; Schlichting, I; Ullrich, J; Rudenko, A

    2013-02-01

    Ionization and fragmentation of methylselenol (CH(3)SeH) molecules by intense (>10(17) W/cm(2)) 5 fs x-ray pulses (ħω=2 keV) are studied by coincident ion momentum spectroscopy. We contrast the measured charge state distribution with data on atomic Kr, determine kinetic energies of resulting ionic fragments, and compare them to the outcome of a Coulomb explosion model. We find signatures of ultrafast charge redistribution from the inner-shell ionized Se atom to its molecular partners, and observe significant displacement of the atomic constituents in the course of multiple ionization.

  14. Improved docking, screening and selectivity prediction for small molecule nuclear receptor modulators using conformational ensembles

    NASA Astrophysics Data System (ADS)

    Park, So-Jung; Kufareva, Irina; Abagyan, Ruben

    2010-05-01

    Nuclear receptors (NRs) are ligand dependent transcriptional factors and play a key role in reproduction, development, and homeostasis of organism. NRs are potential targets for treatment of cancer and other diseases such as inflammatory diseases, and diabetes. In this study, we present a comprehensive library of pocket conformational ensembles of thirteen human nuclear receptors (NRs), and test the ability of these ensembles to recognize their ligands in virtual screening, as well as predict their binding geometry, functional type, and relative binding affinity. 157 known NR modulators and 66 structures were used as a benchmark. Our pocket ensemble library correctly predicted the ligand binding poses in 94% of the cases. The models were also highly selective for the active ligands in virtual screening, with the areas under the ROC curves ranging from 82 to a remarkable 99%. Using the computationally determined receptor-specific binding energy offsets, we showed that the ensembles can be used for predicting selectivity profiles of NR ligands. Our results evaluate and demonstrate the advantages of using receptor ensembles for compound docking, screening, and profiling.

  15. Molecular phylogenetics of subfamily Ornithogaloideae (Hyacinthaceae) based on nuclear and plastid DNA regions, including a new taxonomic arrangement

    PubMed Central

    Martínez-Azorín, Mario; Crespo, Manuel B.; Juan, Ana; Fay, Michael F.

    2011-01-01

    Background and Aims The taxonomic arrangement within subfamily Ornithogaloideae (Hyacinthaceae) has been a matter of controversy in recent decades: several new taxonomic treatments have been proposed, based exclusively on plastid DNA sequences, and these have resulted in classifications which are to a great extent contradictory. Some authors have recognized only a single genus Ornithogalum for the whole subfamily, including 250–300 species of variable morphology, whereas others have recognized many genera. In the latter case, the genera are inevitably much smaller and they are better defined morphologically. However, some are not monophyletic as circumscribed. Methods Phylogenetic analyses of Ornithogaloideae were based on nucleotide sequences of four plastid regions (trnL intron, trnL-F spacer, rbcL and matK) and a nuclear region (ITS). Eighty species covering all relevant taxonomic groups previously recognized in the subfamily were sampled. Parsimony and Bayesian analyses were performed. The molecular data were compared with a matrix of 34 morphological characters. Key Results Combinations of plastid and nuclear data yielded phylogenetic trees which are better resolved than those obtained with any plastid region alone or plastid regions in combination. Three main clades are found, corresponding to the previously recognized tribes Albuceae, Dipcadieae and Ornithogaleae. In these, up to 19 clades are described which are definable by morphology and biogeography. These mostly correspond to previously described taxa, though some need recircumscription. Morphological characters are assessed for their diagnostic value for taxonomy in the subfamily. Conclusions On the basis of the phylogenetic analyses, 19 monophyletic genera are accepted within Ornithogaloideae: Albuca, Avonsera, Battandiera, Cathissa, Coilonox, Dipcadi, Eliokarmos, Elsiea, Ethesia, Galtonia, Honorius, Loncomelos, Melomphis, Neopatersonia, Nicipe, Ornithogalum, Pseudogaltonia, Stellarioides and

  16. LETTER TO THE EDITOR: Collective modes of tri-nuclear molecules of the type 96Sr+ 10Be+ 146Ba

    NASA Astrophysics Data System (ADS)

    Hess, P. O.; Scheid, W.; Greiner, W.; Hamilton, J. H.

    1999-12-01

    The collective modes of the tri-nuclear molecule 96Sr+ 10Be+ 146Ba, observed in recent cold fission decay of 252Cf into three clusters, are theoretically investigated. The main excitations are rotations, the butterfly and belly-dancer modes and icons/Journals/Common/beta" ALT="beta" ALIGN="TOP"/>- and icons/Journals/Common/gamma" ALT="gamma" ALIGN="TOP"/>-vibrations. Due to the presence of the Be nucleus, butterfly excitation energies are shifted up to 2 MeV. There are only a few collective states below 1 MeV which are not rotational. The first rotational level of spin 2+ lies at an energy of about 6 keV. Proposals of how these collective modes may be measured are suggested.

  17. Nuclear dynamics and spectator effects in resonant inelastic soft x-ray scattering of gas-phase water molecules

    SciTech Connect

    Weinhardt, Lothar; Benkert, Andreas; Meyer, Frank; Blum, Monika; Wilks, Regan G.; Yang, Wanli; Baer, Marcus; Reinert, Friedrich; and others

    2012-04-14

    The electronic structure of gas-phase H{sub 2}O and D{sub 2}O molecules has been investigated using resonant inelastic soft x-ray scattering (RIXS). We observe spectator shifts for all valence orbitals when exciting into the lowest three absorption resonances. Strong changes of the relative valence orbital emission intensities are found when exciting into the different absorption resonances, which can be related to the angular anisotropy of the RIXS process. Furthermore, excitation into the 4a{sub 1} resonance leads to nuclear dynamics on the time scale of the RIXS process; we find evidence for vibrational coupling and molecular dissociation in both, the spectator and the participant emission.

  18. RelB nuclear translocation regulates B cell MHC molecule, CD40 expression, and antigen-presenting cell function

    PubMed Central

    O'Sullivan, Brendan J.; MacDonald, Kelli P. A.; Pettit, Allison R.; Thomas, Ranjeny

    2000-01-01

    Mice with targeted RelB mutations demonstrated an essential role for RelB in immune responses and in myeloid dendritic cell differentiation. Human studies suggested a more global transcriptional role in antigen presentation. Burkitt lymphoma cell lines were used as a model to examine the role of RelB in antigen presentation. After transient transfection of BJAB with RelB, strong nuclear expression of RelB-p50 heterodimers was associated with increased APC function and expression of CD40 and MHC class I. Antisense RelB in DG75 reduced antigen-presenting capacity and CD40-mediated up-regulation of MHC molecules. The data indicate that RelB transcriptional activity directly affects antigen presentation and CD40 synthesis. Stimulation of RelB transcriptional activity may provide a positive feedback loop for facilitating productive APC/T cell interactions. PMID:11027342

  19. Enhanced effect of C P -violating nuclear magnetic quadrupole moment in a HfF+ molecule

    NASA Astrophysics Data System (ADS)

    Skripnikov, L. V.; Titov, A. V.; Flambaum, V. V.

    2017-02-01

    The HfF+ cation is a very promising system to use in the search for the electron electric dipole moment (EDM), and a corresponding experiment is carried out by JILA group [H. Loh, K. C. Cossel, M. C. Grau, K.-K. Ni, E. R. Meyer, J. L. Bohn, J. Ye, and E. A. Cornell, Science 342, 1220 (2013), 10.1126/science.1243683; K.-K. Ni, H. Loh, M. Grau, K. C. Cossel, J. Ye, and E. A. Cornell, J. Mol. Spectrosc. 300, 12 (2014), 10.1016/j.jms.2014.02.001. Here we theoretically investigate the cation to search for another effect which violates time-reversal (T ) and spatial parity (P ) symmetries—the nuclear magnetic quadrupole moment (MQM) interaction with electrons. We report an accurate ab initio relativistic electronic structure calculations of the molecular parameter WM=0.494 10/33Hz e cm2 that is required to interpret the experimental data in terms of the MQM of the Hf nucleus. For this we have implemented and applied the combined Dirac-Coulomb(-Gaunt) and relativistic effective core potential approaches to treat electron correlation effects from all of the electrons and to take into account high-order correlation effects using the coupled cluster method with single, double, triple and noniterative quadruple cluster amplitudes. We discuss interpretation of the MQM effect in terms of the strength constants of T ,P -odd nuclear forces, proton and neutron EDMs, the QCD parameter θ , and quark chromo-EDMs.

  20. Nuclear Magnetic Resonance of Hydrogen Molecules Trapped inside C70 Fullerene Cages

    PubMed Central

    Mamone, Salvatore; Concistrè, Maria; Heinmaa, Ivo; Carravetta, Marina; Kuprov, Ilya; Wall, Gary; Denning, Mark; Lei, Xuegong; Chen, Judy Y-C; Li, Yongjun; Murata, Yasujiro; Turro, Nicholas J; Levitt, Malcolm H

    2013-01-01

    We present a solid-state NMR study of H2 molecules confined inside the cavity of C70 fullerene cages over a wide range of temperatures (300 K to 4 K). The proton NMR spectra are consistent with a model in which the dipole–dipole coupling between the ortho-H2 protons is averaged over the rotational/translational states of the confined quantum rotor, with an additional chemical shift anisotropy δHCSA=10.1 ppm induced by the carbon cage. The magnitude of the chemical shift anisotropy is consistent with DFT estimates of the chemical shielding tensor field within the cage. The experimental NMR data indicate that the ground state of endohedral ortho-H2 in C70 is doubly degenerate and polarized transverse to the principal axis of the cage. The NMR spectra indicate significant magnetic alignment of the C70 long axes along the magnetic field, at temperatures below ∼10 K. PMID:23788291

  1. Identification of Novel Small Molecule Activators of Nuclear Factor-κB With Neuroprotective Action Via High-Throughput Screening

    PubMed Central

    Manuvakhova, Marina S.; Johnson, Guyla G.; White, Misti C.; Ananthan, Subramaniam; Sosa, Melinda; Maddox, Clinton; McKellip, Sara; Rasmussen, Lynn; Wennerberg, Krister; Hobrath, Judith V.; White, E. Lucile; Maddry, Joseph A.; Grimaldi, Maurizio

    2012-01-01

    Neuronal noncytokine-dependent p50/p65 nuclear factor-κB (the primary NF-κB complex in the brain) activation has been shown to exert neuroprotective actions. Thus neuronal activation of NF-κB could represent a viable neuroprotective target. We have developed a cell-based assay able to detect NF-κB expression enhancement, and through its use we have identified small molecules able to up-regulate NF-κB expression and hence trigger its activation in neurons. We have successfully screened approximately 300,000 compounds and identified 1,647 active compounds. Cluster analysis of the structures within the hit population yielded 14 enriched chemical scaffolds. One high-potency and chemically attractive representative of each of these 14 scaffolds and four singleton structures were selected for follow-up. The experiments described here highlighted that seven compounds caused noncanonical long-lasting NF-κB activation in primary astrocytes. Molecular NF-κB docking experiments indicate that compounds could be modulating NF-κB-induced NF-κB expression via enhancement of NF-κB binding to its own promoter. Prototype compounds increased p65 expression in neurons and caused its nuclear translocation without affecting the inhibitor of NF-κB (I-κB). One of the prototypical compounds caused a large reduction of glutamate-induced neuronal death. In conclusion, we have provided evidence that we can use small molecules to activate p65 NF-κB expression in neurons in a cytokine receptor-independent manner, which results in both long-lasting p65 NF-κB translocation/activation and decreased glutamate neurotoxicity. PMID:21046675

  2. Fully automated quantum chemistry based computation of spin-spin coupled nuclear magnetic resonance spectra for molecules.

    PubMed

    Grimme, Stefan; Bannwarth, Christoph; Dohm, Sebastian; Hansen, Andreas; Pisarek, Jana; Pracht, Philipp; Seibert, Jakob; Neese, Frank

    2017-09-14

    We present a composite procedure for the quantum chemical computation of spin-spin coupled 1H-NMR spectra for general, flexible molecules in solution. It is based on four main steps, namely, conformer/rotamer ensemble (CRE) generation by the fast tight-binding method GFN-xTB and a newly developed search algorithm, relative free energy and NMR parameter computation, and solution of the spin-Hamiltonian. In this way the NMR-specific nuclear permutation problem is solved and the correct spin-symmetries are obtained. Energies, shieldings, and spin-spin couplings are computed at state-of-the-art DFT levels employing continuum solvation. A few (in)organic and transition metal complexes are presented and very good, unprecedented agreement between theoretical and experimental spectra is achieved. The approach is routinely applicable to systems with up to 100-150 atoms and may open new avenues for a detailed (conformational) structure elucidation of e.g. natural products or drug molecules. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Zearalenone Mycotoxin Affects Immune Mediators, MAPK Signalling Molecules, Nuclear Receptors and Genome-Wide Gene Expression in Pig Spleen

    PubMed Central

    Pistol, Gina Cecilia; Braicu, Cornelia; Motiu, Monica; Gras, Mihail Alexandru; Marin, Daniela Eliza; Stancu, Mariana; Calin, Loredana; Israel-Roming, Florentina; Berindan-Neagoe, Ioana; Taranu, Ionelia

    2015-01-01

    The toxicity of zearalenone (ZEA) was evaluated in swine spleen, a key organ for the innate and adaptative immune response. Weaned pigs were fed for 18 days with a control or a ZEA contaminated diet. The effect of ZEA was assessed on wide genome expression, pro- (TNF-α, IL-8, IL-6, IL-1β, IFN-γ) and anti-inflammatory (IL-10, IL-4) cytokines, other molecules involved in inflammatory processes (MMPs/TIMPs), as well as signaling molecules, (p38/JNK1/JNK2-MAPKs) and nuclear receptors (PPARγ/NFkB/AP-1/STAT3/c-JUN). Microarray analysis showed that 46% of total number of differentially expressed genes was involved in cellular signaling pathway, 13% in cytokine network and 10% in the inflammatory response. ZEA increased expression and synthesis of pro- inflammatory (TNF-α, IL-8, IL-6, IL-1β) and had no effect on IFN-γ, IL-4 and IL-10 cytokines in spleen. The inflammatory stimulation might be a consequence of JNK pathway activation rather than of p-38MAPK and NF-kB involvement whose gene and protein expression were suppressed by ZEA action. In summary, our findings indicated the role of ZEA as an immune disruptor at spleen level. PMID:26011631

  4. Configuration interaction study including the effects of spin-orbit coupling for the electronic states of the LiX molecules (X = C, Si, Ge, Sn)

    NASA Astrophysics Data System (ADS)

    Rai-Constapel, Vidisha; Liebermann, Heinz-Peter; Alekseyev, Aleksey B.; Buenker, Robert J.

    2011-03-01

    Ab initio multireference configuration interaction calculations including spin-orbit coupling effects have been carried out for four LiX molecules (X = C, Si, Ge and Sn). Potential energy curves of the ground and low-lying excited states have been obtained in each case as well as the corresponding spectroscopic constants. Transition moments have also been computed in order to give estimates of the radiative lifetimes of the excited states for each system. Trends in a variety of quantities such as T e values, spin-orbit splittings, equilibrium bond lengths and vibrational frequencies for this series of molecules are discussed in detail and comparison with the corresponding data reported earlier for the PbLi system is also made.

  5. Nuclear c-Abl-mediated tyrosine phosphorylation induces chromatin structural changes through histone modifications that include H4K16 hypoacetylation

    SciTech Connect

    Aoyama, Kazumasa; Fukumoto, Yasunori; Ishibashi, Kenichi; Kubota, Sho; Morinaga, Takao; Horiike, Yasuyoshi; Yuki, Ryuzaburo; Takahashi, Akinori; Nakayama, Yuji; Yamaguchi, Naoto

    2011-12-10

    c-Abl tyrosine kinase, which is ubiquitously expressed, has three nuclear localization signals and one nuclear export signal and can shuttle between the nucleus and the cytoplasm. c-Abl plays important roles in cell proliferation, adhesion, migration, and apoptosis. Recently, we developed a pixel imaging method for quantitating the level of chromatin structural changes and showed that nuclear Src-family tyrosine kinases are involved in chromatin structural changes upon growth factor stimulation. Using this method, we show here that nuclear c-Abl induces chromatin structural changes in a manner dependent on the tyrosine kinase activity. Expression of nuclear-targeted c-Abl drastically increases the levels of chromatin structural changes, compared with that of c-Abl. Intriguingly, nuclear-targeted c-Abl induces heterochromatic profiles of histone methylation and acetylation, including hypoacetylation of histone H4 acetylated on lysine 16 (H4K16Ac). The level of heterochromatic histone modifications correlates with that of chromatin structural changes. Adriamycin-induced DNA damage stimulates translocation of c-Abl into the nucleus and induces chromatin structural changes together with H4K16 hypoacetylation. Treatment with trichostatin A, a histone deacetylase inhibitor, blocks chromatin structural changes but not nuclear tyrosine phosphorylation by c-Abl. These results suggest that nuclear c-Abl plays an important role in chromatin dynamics through nuclear tyrosine phosphorylation-induced heterochromatic histone modifications.

  6. Simple expressions of the nuclear relaxation rate enhancement due to quadrupole nuclei in slowly tumbling molecules

    SciTech Connect

    Fries, Pascal H.; Belorizky, Elie

    2015-07-28

    For slowly tumbling entities or quasi-rigid lattices, we derive very simple analytical expressions of the quadrupole relaxation enhancement (QRE) of the longitudinal relaxation rate R{sub 1} of nuclear spins I due to their intramolecular magnetic dipolar coupling with quadrupole nuclei of arbitrary spins S ≥ 1. These expressions are obtained by using the adiabatic approximation for evaluating the time evolution operator of the quantum states of the quadrupole nuclei S. They are valid when the gyromagnetic ratio of the spin S is much smaller than that of the spin I. The theory predicts quadrupole resonant peaks in the dispersion curve of R{sub 1} vs magnetic field. The number, positions, relative intensities, Lorentzian shapes, and widths of these peaks are explained in terms of the following properties: the magnitude of the quadrupole Hamiltonian and the asymmetry parameter of the electric field gradient (EFG) acting on the spin S, the S-I inter-spin orientation with respect to the EFG principal axes, the rotational correlation time of the entity carrying the S–I pair, and/or the proper relaxation time of the spin S. The theory is first applied to protein amide protons undergoing dipolar coupling with fast-relaxing quadrupole {sup 14}N nuclei and mediating the QRE to the observed bulk water protons. The theoretical QRE agrees well with its experimental counterpart for various systems such as bovine pancreatic trypsin inhibitor and cartilages. The anomalous behaviour of the relaxation rate of protons in synthetic aluminium silicate imogolite nano-tubes due to the QRE of {sup 27}Al (S = 5/2) nuclei is also explained.

  7. Simple expressions of the nuclear relaxation rate enhancement due to quadrupole nuclei in slowly tumbling molecules

    NASA Astrophysics Data System (ADS)

    Fries, Pascal H.; Belorizky, Elie

    2015-07-01

    For slowly tumbling entities or quasi-rigid lattices, we derive very simple analytical expressions of the quadrupole relaxation enhancement (QRE) of the longitudinal relaxation rate R1 of nuclear spins I due to their intramolecular magnetic dipolar coupling with quadrupole nuclei of arbitrary spins S ≥ 1. These expressions are obtained by using the adiabatic approximation for evaluating the time evolution operator of the quantum states of the quadrupole nuclei S. They are valid when the gyromagnetic ratio of the spin S is much smaller than that of the spin I. The theory predicts quadrupole resonant peaks in the dispersion curve of R1 vs magnetic field. The number, positions, relative intensities, Lorentzian shapes, and widths of these peaks are explained in terms of the following properties: the magnitude of the quadrupole Hamiltonian and the asymmetry parameter of the electric field gradient (EFG) acting on the spin S, the S-I inter-spin orientation with respect to the EFG principal axes, the rotational correlation time of the entity carrying the S-I pair, and/or the proper relaxation time of the spin S. The theory is first applied to protein amide protons undergoing dipolar coupling with fast-relaxing quadrupole 14N nuclei and mediating the QRE to the observed bulk water protons. The theoretical QRE agrees well with its experimental counterpart for various systems such as bovine pancreatic trypsin inhibitor and cartilages. The anomalous behaviour of the relaxation rate of protons in synthetic aluminium silicate imogolite nano-tubes due to the QRE of 27Al (S = 5/2) nuclei is also explained.

  8. Effective method for the computation of optical spectra of large molecules at finite temperature including the Duschinsky and Herzberg-Teller effect: The Qx band of porphyrin as a case study

    NASA Astrophysics Data System (ADS)

    Santoro, Fabrizio; Lami, Alessandro; Improta, Roberto; Bloino, Julien; Barone, Vincenzo

    2008-06-01

    The authors extend their recent method for the computation of vibrationally resolved optical spectra of large molecules, including both the Duschinsky rotation and the effect of finite temperature in the framework of the Franck-Condon (FC) approximation, to deal with the more general case of the Herzberg-Teller (HT) model, where also the linear dependence of the transition dipole moment on the nuclear coordinates is taken into account. This generalization allows us to investigate weak and vibronically allowed transitions by far extending the range of application of the method. The calculation of the spectra of sizable molecules is computationally demanding because of the huge number of final vibrational states that must be taken into account, and the inclusion of HT terms further increases the computational burden. The method presented here automatically selects the relevant vibronic contributions to the spectrum, independent of their frequency, and it is able to provide fully converged spectra with a modest computational requirement. The effectiveness of the method is illustrated by computing the HT absorption and fluorescence Qx spectra of free-base porphyrin both at T=0 K and at room temperature, performing for the first time an exact treatment of vibrations in harmonic approximation. Qx spectra are compared to experiments and FC/HT interferences are analyzed in detail.

  9. Unilateral vestibular deafferentation-induced changes in calcium signaling-related molecules in the rat vestibular nuclear complex.

    PubMed

    Masumura, Chisako; Horii, Arata; Mitani, Kenji; Kitahara, Tadashi; Uno, Atsuhiko; Kubo, Takeshi

    2007-03-23

    Inquiries into the neurochemical mechanisms of vestibular compensation, a model of lesion-induced neuronal plasticity, reveal the involvement of both voltage-gated Ca(2+) channels (VGCC) and intracellular Ca(2+) signaling. Indeed, our previous microarray analysis showed an up-regulation of some calcium signaling-related genes such as the alpha2 subunit of L-type calcium channels, calcineurin, and plasma membrane Ca(2+) ATPase 1 (PMCA1) in the ipsilateral vestibular nuclear complex (VNC) following unilateral vestibular deafferentation (UVD). To further elucidate the role of calcium signaling-related molecules in vestibular compensation, we used a quantitative real-time polymerase chain reaction (PCR) method to confirm the microarray results and investigated changes in expression of these molecules at various stages of compensation (6 h to 2 weeks after UVD). We also investigated the changes in gene expression during Bechterew's phenomenon and the effects of a calcineurin inhibitor on vestibular compensation. Real-time PCR showed that genes for the alpha2 subunit of VGCC, PMCA2, and calcineurin were transiently up-regulated 6 h after UVD in ipsilateral VNC. A subsequent UVD, which induced Bechterew's phenomenon, reproduced a complete mirror image of the changes in gene expressions of PMCA2 and calcineurin seen in the initial UVD, while the alpha2 subunit of VGCC gene had a trend to increase in VNC ipsilateral to the second lesion. Pre-treatment by FK506, a calcineurin inhibitor, decelerated the vestibular compensation in a dose-dependent manner. Although it is still uncertain whether these changes in gene expression are causally related to the molecular mechanisms of vestibular compensation, this observation suggests that after increasing the Ca(2+) influx into the ipsilateral VNC neurons via up-regulated VGCC, calcineurin may be involved in their synaptic plasticity. Conversely, an up-regulation of PMCA2, a brain-specific Ca(2+) pump, would increase an efflux of Ca

  10. Identification of a small molecule inhibitor of importin beta mediated nuclear import by confocal on-bead screening of tagged one-bead one-compound libraries

    PubMed Central

    Hintersteiner, Martin; Ambrus, Géza; Bednenko, Janna; Schmied, Mario; Knox, Andrew J.S.; Gstach, Hubert; Seifert, Jan-Marcus; Singer, Eric L.; Gerace, Larry; Auer, Manfred

    2010-01-01

    In eukaryotic cells, proteins and RNA are transported between the nucleus and the cytoplasm by nuclear import and export receptors. Over the past decade, small molecules that inhibit the nuclear export receptor CRM1 have been identified, most notably leptomycin B. However, up to now no small molecule inhibitors of nuclear import have been described. Here we have used our automated Confocal Nanoscanning and bead picking method (CONA) for on-bead screening of a one bead/one compound library to identify the first such import inhibitor, karyostatin 1A. Karyostatin 1A binds importin β with high nanomolar affinity and specifically inhibits importin α/β mediated nuclear import at low micromolar concentrations in vitro and in living cells, without perturbing transportin mediated nuclear import or CRM1 mediated nuclear export. Surface plasmon resonance binding experiments suggest that karyostatin 1A acts by disrupting the interaction between importin β and the GTPase Ran. As a selective inhibitor of the importin α/β import pathway, karyostatin 1A will provide a valuable tool for future studies of nucleocytoplasmic trafficking. PMID:20677820

  11. Electron-nuclear dynamics of the one-electron nonlinear polyatomic molecule H32+ in ultrashort intense laser pulses

    NASA Astrophysics Data System (ADS)

    Lefebvre, C.; Lu, H. Z.; Chelkowski, S.; Bandrauk, A. D.

    2014-02-01

    A quantum description of the one-electron triangular H32+ molecular ion, beyond the Born-Oppenheimer approximation, is used to study the full influence of the nuclear motion on the high-intensity photoionization and harmonic generation processes. A detailed analysis of electron and proton motions and their time-dependent acceleration allows for identification of the main electron recollision events as a function of time-dependent configuration of the protons. High-order-harmonic generation photons are shown to be produced by single-electron recollision in the second half of the pulse envelope, which also induces a redshift in the harmonics, due to the rapid few-femtosecond motions of protons. Perpendicular harmonics are produced, in general, with a linearly polarized laser pulse parallel to a bond of the triangular molecule, and, in particular, the harmonics in the cutoff region are elliptically polarized. When the laser-pulse polarization is parallel to a symmetry axis of the triangular molecular ion, creation and destruction of the chemical bond perpendicular to the polarization is predicted on a near-femtosecond time scale.

  12. Quantum wavepacket ab initio molecular dynamics: an approach for computing dynamically averaged vibrational spectra including critical nuclear quantum effects.

    PubMed

    Sumner, Isaiah; Iyengar, Srinivasan S

    2007-10-18

    We have introduced a computational methodology to study vibrational spectroscopy in clusters inclusive of critical nuclear quantum effects. This approach is based on the recently developed quantum wavepacket ab initio molecular dynamics method that combines quantum wavepacket dynamics with ab initio molecular dynamics. The computational efficiency of the dynamical procedure is drastically improved (by several orders of magnitude) through the utilization of wavelet-based techniques combined with the previously introduced time-dependent deterministic sampling procedure measure to achieve stable, picosecond length, quantum-classical dynamics of electrons and nuclei in clusters. The dynamical information is employed to construct a novel cumulative flux/velocity correlation function, where the wavepacket flux from the quantized particle is combined with classical nuclear velocities to obtain the vibrational density of states. The approach is demonstrated by computing the vibrational density of states of [Cl-H-Cl]-, inclusive of critical quantum nuclear effects, and our results are in good agreement with experiment. A general hierarchical procedure is also provided, based on electronic structure harmonic frequencies, classical ab initio molecular dynamics, computation of nuclear quantum-mechanical eigenstates, and employing quantum wavepacket ab initio dynamics to understand vibrational spectroscopy in hydrogen-bonded clusters that display large degrees of anharmonicities.

  13. Torsion-inversion tunneling patterns in the CH-stretch vibrationally excited states of the G12 family of molecules including methylamine.

    PubMed

    Dawadi, Mahesh B; Bhatta, Ram S; Perry, David S

    2013-12-19

    Two torsion-inversion tunneling models (models I and II) are reported for the CH-stretch vibrationally excited states in the G12 family of molecules. The torsion and inversion tunneling parameters, h(2v) and h(3v), respectively, are combined with low-order coupling terms involving the CH-stretch vibrations. Model I is a group theoretical treatment starting from the symmetric rotor methyl CH-stretch vibrations; model II is an internal coordinate model including the local-local CH-stretch coupling. Each model yields predicted torsion-inversion tunneling patterns of the four symmetry species, A, B, E1, and E2, in the CH-stretch excited states. Although the predicted tunneling patterns for the symmetric CH-stretch excited state are the same as for the ground state, inverted tunneling patterns are predicted for the asymmetric CH-stretches. The qualitative tunneling patterns predicted are independent of the model type and of the particular coupling terms considered. In model I, the magnitudes of the tunneling splittings in the two asymmetric CH-stretch excited states are equal to half of that in the ground state, but in model II, they differ when the tunneling rate is fast. The model predictions are compared across the series of molecules methanol, methylamine, 2-methylmalonaldehyde, and 5-methyltropolone and to the available experimental data.

  14. Expansion Hamiltonian model for a diatomic molecule adsorbed on a surface: Vibrational states of the CO/Cu(100) system including surface vibrations

    NASA Astrophysics Data System (ADS)

    Meng, Qingyong; Meyer, Hans-Dieter

    2015-10-01

    Molecular-surface studies are often done by assuming a corrugated, static (i.e., rigid) surface. To be able to investigate the effects that vibrations of surface atoms may have on spectra and cross sections, an expansion Hamiltonian model is proposed on the basis of the recently reported [R. Marquardt et al., J. Chem. Phys. 132, 074108 (2010)] SAP potential energy surface (PES), which was built for the CO/Cu(100) system with a rigid surface. In contrast to other molecule-surface coupling models, such as the modified surface oscillator model, the coupling between the adsorbed molecule and the surface atoms is already included in the present expansion SAP-PES model, in which a Taylor expansion around the equilibrium positions of the surface atoms is performed. To test the quality of the Taylor expansion, a direct model, that is avoiding the expansion, is also studied. The latter, however, requests that there is only one movable surface atom included. On the basis of the present expansion and direct models, the effects of a moving top copper atom (the one to which CO is bound) on the energy levels of a bound CO/Cu(100) system are studied. For this purpose, the multiconfiguration time-dependent Hartree calculations are carried out to obtain the vibrational fundamentals and overtones of the CO/Cu(100) system including a movable top copper atom. In order to interpret the results, a simple model consisting of two coupled harmonic oscillators is introduced. From these calculations, the vibrational levels of the CO/Cu(100) system as function of the frequency of the top copper atom are discussed.

  15. Expansion Hamiltonian model for a diatomic molecule adsorbed on a surface: Vibrational states of the CO/Cu(100) system including surface vibrations

    SciTech Connect

    Meng, Qingyong; Meyer, Hans-Dieter

    2015-10-28

    Molecular-surface studies are often done by assuming a corrugated, static (i.e., rigid) surface. To be able to investigate the effects that vibrations of surface atoms may have on spectra and cross sections, an expansion Hamiltonian model is proposed on the basis of the recently reported [R. Marquardt et al., J. Chem. Phys. 132, 074108 (2010)] SAP potential energy surface (PES), which was built for the CO/Cu(100) system with a rigid surface. In contrast to other molecule-surface coupling models, such as the modified surface oscillator model, the coupling between the adsorbed molecule and the surface atoms is already included in the present expansion SAP-PES model, in which a Taylor expansion around the equilibrium positions of the surface atoms is performed. To test the quality of the Taylor expansion, a direct model, that is avoiding the expansion, is also studied. The latter, however, requests that there is only one movable surface atom included. On the basis of the present expansion and direct models, the effects of a moving top copper atom (the one to which CO is bound) on the energy levels of a bound CO/Cu(100) system are studied. For this purpose, the multiconfiguration time-dependent Hartree calculations are carried out to obtain the vibrational fundamentals and overtones of the CO/Cu(100) system including a movable top copper atom. In order to interpret the results, a simple model consisting of two coupled harmonic oscillators is introduced. From these calculations, the vibrational levels of the CO/Cu(100) system as function of the frequency of the top copper atom are discussed.

  16. Nuclear domain 'knock-in' screen for the evaluation and identification of small molecule enhancers of CRISPR-based genome editing.

    PubMed

    Pinder, Jordan; Salsman, Jayme; Dellaire, Graham

    2015-10-30

    CRISPR is a genome-editing platform that makes use of the bacterially-derived endonuclease Cas9 to introduce DNA double-strand breaks at precise locations in the genome using complementary guide RNAs. We developed a nuclear domain knock-in screen, whereby the insertion of a gene encoding the green fluorescent protein variant Clover is inserted by Cas9-mediated homology directed repair (HDR) within the first exon of genes that are required for the structural integrity of subnuclear domains such as the nuclear lamina and promyelocytic leukemia nuclear bodies (PML NBs). Using this approach, we compared strategies for enhancing CRISPR-mediated HDR, focusing on known genes and small molecules that impact non-homologous end joining (NHEJ) and homologous recombination (HR). Ultimately, we identified the small molecule RS-1 as a potent enhancer of CRISPR-based genome editing, enhancing HDR 3- to 6-fold depending on the locus and transfection method. We also characterized U2OS human osteosarcoma cells expressing Clover-tagged PML and demonstrate that this strategy generates cell lines with PML NBs that are structurally and functionally similar to bodies in the parental cell line. Thus, the nuclear domain knock-in screen that we describe provides a simple means of rapidly evaluating methods and small molecules that have the potential to enhance Cas9-mediated HDR.

  17. Nuclear domain ‘knock-in’ screen for the evaluation and identification of small molecule enhancers of CRISPR-based genome editing

    PubMed Central

    Pinder, Jordan; Salsman, Jayme; Dellaire, Graham

    2015-01-01

    CRISPR is a genome-editing platform that makes use of the bacterially-derived endonuclease Cas9 to introduce DNA double-strand breaks at precise locations in the genome using complementary guide RNAs. We developed a nuclear domain knock-in screen, whereby the insertion of a gene encoding the green fluorescent protein variant Clover is inserted by Cas9-mediated homology directed repair (HDR) within the first exon of genes that are required for the structural integrity of subnuclear domains such as the nuclear lamina and promyelocytic leukemia nuclear bodies (PML NBs). Using this approach, we compared strategies for enhancing CRISPR-mediated HDR, focusing on known genes and small molecules that impact non-homologous end joining (NHEJ) and homologous recombination (HR). Ultimately, we identified the small molecule RS-1 as a potent enhancer of CRISPR-based genome editing, enhancing HDR 3- to 6-fold depending on the locus and transfection method. We also characterized U2OS human osteosarcoma cells expressing Clover-tagged PML and demonstrate that this strategy generates cell lines with PML NBs that are structurally and functionally similar to bodies in the parental cell line. Thus, the nuclear domain knock-in screen that we describe provides a simple means of rapidly evaluating methods and small molecules that have the potential to enhance Cas9-mediated HDR. PMID:26429972

  18. Nuclear pore complex contains a family of glycoproteins that includes p62: glycosylation through a previously unidentified cellular pathway

    SciTech Connect

    Davis, L.I.; Blobel, G.

    1987-11-01

    Using a monoclonal antibody (mAb 414), the authors previously identified a protein of 62 kDa (p62) that was localized to the nuclear pore complex by immunoelectron microscopy. They also showed that p62 binds specifically to wheat germ agglutinin. Therefore, they proposed that this nuclear pore complex protein might be a member of a recently characterized family of glycoproteins that are labeled by in vitro galactosylation of rat liver nuclei and contain O-linked monosaccharidic GlcNAc residues. In support of this, they now show that incubation with N-acetylglucosaminidase reduces the molecular mass of p62 by approx. = 3 kDa because of the removal of terminal GlcNAc residues. Moreover, p62 can be galactosylated in vitro by using UDP-(/sup 3/H)galactose and galactosyltransferase. They also show that most of the GlcNAc residues are added within 5 min of synthesis, when p62 is soluble and cytosolic. Thus, the addition of GlcNAc is carried out in the cytoplasm and is clearly distinct from the N- and O-linked glycosylation pathways of the endoplasmic reticulum and Golgi complex. Using another mAb with a broad specificity for nuclear GlcNAc-containing proteins, they show by immunofluorescence and protein blotting of subnuclear fractions that some of these proteins are in the interior of the nucleus, and others are most likely located in the pore complex.

  19. A novel anticancer effect of thalidomide: inhibition of intercellular adhesion molecule-1-mediated cell invasion and metastasis through suppression of nuclear factor-kappaB.

    PubMed

    Lin, Yi-Chu; Shun, Chia-Tung; Wu, Ming-Shiang; Chen, Ching-Chow

    2006-12-01

    Thalidomide has been reported to have antiangiogenic and antimetastatic effects. Intercellular adhesion molecule-1 (ICAM-1) was shown to be involved in monocyte adherence to epithelial cells and cancer cell invasion. In this study, we further investigated the role of ICAM-1 in tumorigenesis, including tumor formation and metastasis. ICAM-1 as a molecular target for cancer and the anticancer effect of thalidomide were investigated. Expression of ICAM-1 protein in human lung cancer specimens was assessed by immunohistochemistry. ICAM-1 overexpressing A549 cells (A549/ICAM-1) were established to investigate the direct effect of ICAM-1 on in vitro cell invasion and in vivo tumor metastasis. Transient transfection and luciferase assay, electrophoretic mobility shift assay, and chromatin immunoprecipitation were done to assess the activity and binding of nuclear factor-kappaB to the ICAM-1 promoter. A xenograft model in nude mice was conducted to evaluate the anticancer effect of thalidomide. High expression of ICAM-1 in human lung cancer specimens was correlated with a greater risk of advanced cancers (stages III and IV). A549/ICAM-1 cells were shown to induce in vitro cell invasion and in vivo tumor metastasis. Anti-ICAM-1 antibody and thalidomide had inhibitory effect on these events. Thalidomide also suppressed tumor necrosis factor-alpha-induced ICAM-1 expression through inhibition of nuclear factor-kappaB binding to the ICAM-1 promoter. The in vivo xenograft model showed the effectiveness of thalidomide on tumor formation. These studies provide a framework for targeting ICAM-1 as a biologically based therapy for cancer, and thalidomide might be effective in human lung cancer.

  20. Including screening in van der Waals corrected density functional theory calculations: The case of atoms and small molecules physisorbed on graphene

    SciTech Connect

    Silvestrelli, Pier Luigi; Ambrosetti, Alberto

    2014-03-28

    The Density Functional Theory (DFT)/van der Waals-Quantum Harmonic Oscillator-Wannier function (vdW-QHO-WF) method, recently developed to include the vdW interactions in approximated DFT by combining the quantum harmonic oscillator model with the maximally localized Wannier function technique, is applied to the cases of atoms and small molecules (X=Ar, CO, H{sub 2}, H{sub 2}O) weakly interacting with benzene and with the ideal planar graphene surface. Comparison is also presented with the results obtained by other DFT vdW-corrected schemes, including PBE+D, vdW-DF, vdW-DF2, rVV10, and by the simpler Local Density Approximation (LDA) and semilocal generalized gradient approximation approaches. While for the X-benzene systems all the considered vdW-corrected schemes perform reasonably well, it turns out that an accurate description of the X-graphene interaction requires a proper treatment of many-body contributions and of short-range screening effects, as demonstrated by adopting an improved version of the DFT/vdW-QHO-WF method. We also comment on the widespread attitude of relying on LDA to get a rough description of weakly interacting systems.

  1. End of FY2014 Report - Filter Measurement System for Nuclear Material Storage Canisters (Including Altitude Correction for Filter Pressure Drop)

    SciTech Connect

    Moore, Murray E.; Reeves, Kirk Patrick

    2015-02-24

    Two LANL FTS (Filter Test System ) devices for nuclear material storage canisters are fully operational. One is located in PF-4 ( i.e. the TA-55 FTS) while the other is located at the Radiation Protection Division’s Aerosol Engineering Facility ( i.e. the TA-3 FTS). The systems are functionally equivalent , with the TA-3 FTS being the test-bed for new additions and for resolving any issues found in the TA-55 FTS. There is currently one unresolved issue regarding the TA-55 FTS device. The canister lid clamp does not give a leak tight seal when testing the 1 QT (quart) or 2 QT SAVY lids. An adapter plate is being developed that will ensure a correct test configuration when the 1 or 2 QT SAVY lid s are being tested .

  2. Alternative wavefunction ansatz for including explicit electron-proton correlation in the nuclear-electronic orbital approach

    NASA Astrophysics Data System (ADS)

    Ko, Chaehyuk; Pak, Michael V.; Swalina, Chet; Hammes-Schiffer, Sharon

    2011-08-01

    The nuclear-electronic orbital (NEO) approach treats specified nuclei quantum mechanically on the same level as the electrons with molecular orbital techniques. The explicitly correlated Hartree-Fock (NEO-XCHF) approach was developed to incorporate electron-nucleus dynamical correlation directly into the variational optimization of the nuclear-electronic wavefunction. In the original version of this approach, the Hartree-Fock wavefunction is multiplied by (1 + hat G), where hat G is a geminal operator expressed as a sum of Gaussian type geminal functions that depend on the electron-proton distance. Herein, a new wavefunction ansatz is proposed to avoid the computation of five- and six-particle integrals and to simplify the computation of the lower dimensional integrals involving the geminal functions. In the new ansatz, denoted NEO-XCHF2, the Hartree-Fock wavefunction is multiplied by √ {1 + hat G} rather than (1 + hat G). Although the NEO-XCHF2 ansatz eliminates the integrals that are quadratic in the geminal functions, it introduces terms in the kinetic energy integrals with no known analytical solution. A truncated expansion scheme is devised to approximate these problematic terms. An alternative hybrid approach, in which the kinetic energy terms are calculated with the original NEO-XCHF ansatz and the potential energy terms are calculated with the NEO-XCHF2 ansatz, is also implemented. Applications to a series of model systems with up to four electrons provide validation for the NEO-XCHF2 approach and the treatments of the kinetic energy terms.

  3. Local vibrations in disordered solids studied via single-molecule spectroscopy: Comparison with neutron, nuclear, Raman scattering, and photon echo data

    NASA Astrophysics Data System (ADS)

    Vainer, Yu. G.; Naumov, A. V.; Kador, L.

    2008-06-01

    The energy spectrum of low-frequency vibrational modes (LFMs) in three disordered organic solids—amorphous polyisobutylene (PIB), toluene and deuterated toluene glasses, weakly doped with fluorescent chromophore molecules of tetra-tert-butylterrylene (TBT) has been measured via single-molecule (SM) spectroscopy. Analysis of the individual temperature dependences of linewidths of single TBT molecules allowed us to determine the values of the vibrational mode frequencies and the SM-LFM coupling constants for vibrations in the local environment of the molecules. The measured LFM spectra were compared with the “Boson peak” as measured in pure PIB by inelastic neutron scattering, in pure toluene glass by low-frequency Raman scattering, in doped toluene glass by nuclear inelastic scattering, and with photon echo data. The comparative analysis revealed close agreement between the spectra of the local vibrations as measured in the present study and the literature data of the Boson peak in PIB and toluene. The analysis has also the important result that weak doping of the disordered matrices with nonpolar probe molecules whose chemical composition is similar to that of the matrix molecules does not influence the observed vibrational dynamics markedly. The experimental data displaying temporal stability on the time scale of a few hours of vibrational excitation parameters in local surroundings was obtained for the first time both for polymer and molecular glass.

  4. A small molecule induces integrin β4 nuclear translocation and apoptosis selectively in cancer cells with high expression of integrin β4

    PubMed Central

    Liu, ShuYan; Ge, Di; Chen, LiNa; Zhao, Jing; Su, Le; Zhang, ShangLi; Miao, JunYing; Zhao, BaoXiang

    2016-01-01

    Increased integrin β4 (ITGB4) level is accompanied by malignant progression of multiple carcinomas. However, selective therapeutic strategies against cancer cells expressing a high level of ITGB4 have not been reported. Here, for the first time, we report that a chiral small molecule, SEC, selectively promotes apoptosis in cancer cells expressing a high level of ITGB4 by inducing ITGB4 nuclear translocation. Nuclear ITGB4 can bind to the ATF3 promoter region and activate the expression of ATF3, then upregulate the downstream pro-apoptosis genes. Furthermore, SEC promoted the binding of annexin A7 (ANXA7) to ITGB4 and increased ANXA7 GTPase activity. Activated ANXA7 promoted ITGB4 nuclear translocation by triggering ITGB4 phosphorylation at Y1494. SEC also inhibited the growth of xenograft tumors in the avian embryo model. We identified a small molecule, SEC, with selective pro-apoptosis effects on cancer cells with high expression of ITGB4, both in vitro and in vivo, by triggering the binding of ITGB4 and ANXA7, ITGB4 nuclear trafficking, and pro-apoptosis gene expression. PMID:26918348

  5. Observation of zero-point quantum fluctuations of a single-molecule magnet through the relaxation of its nuclear spin bath.

    PubMed

    Morello, A; Millán, A; de Jongh, L J

    2014-03-21

    A single-molecule magnet placed in a magnetic field perpendicular to its anisotropy axis can be truncated to an effective two-level system, with easily tunable energy splitting. The quantum coherence of the molecular spin is largely determined by the dynamics of the surrounding nuclear spin bath. Here we report the measurement of the nuclear spin-lattice relaxation rate 1/T1n in a single crystal of the single-molecule magnet Mn12-ac, at T ≈ 30 mK in perpendicular fields B⊥ up to 9 T. The relaxation channel at B ≈ 0 is dominated by incoherent quantum tunneling of the Mn12-ac spin S, aided by the nuclear bath itself. However for B⊥>5 T we observe an increase of 1/T1n by several orders of magnitude up to the highest field, despite the fact that the molecular spin is in its quantum mechanical ground state. This striking observation is a consequence of the zero-point quantum fluctuations of S, which allow it to mediate the transfer of energy from the excited nuclear spin bath to the crystal lattice at much higher rates. Our experiment highlights the importance of quantum fluctuations in the interaction between an "effective two-level system" and its surrounding spin bath.

  6. The importance of suppressing spin diffusion effects in the accurate determination of the spatial structure of a flexible molecule by nuclear Overhauser effect spectroscopy

    NASA Astrophysics Data System (ADS)

    Khodov, I. A.; Efimov, S. V.; Klochkov, V. V.; Batista de Carvalho, L. A. E.; Kiselev, M. G.

    2016-02-01

    Two-dimensional nuclear Overhauser effect spectroscopy is applied to the elucidation of conformation distribution of small molecules in solution. An essential influence of the nonlinear multistep magnetization transfer (spin diffusion) on the NMR-based analysis of conformers distribution for small druglike molecules in solution was revealed. Therefore, the spin diffusion should be eliminated from the obtained NMR data in order to obtain accurate results. Efficiency of QUIET-NOESY spectroscopy in solving the problem of accurate determination of inter-proton distances in a small molecule was shown in a study of ibuprofen. Although it requires much experimental time, this technique was found to be helpful to solve the spin diffusion problem.

  7. Electric properties of the 3-methyl-4-nitropyridine-1-oxyde (POM) molecules in solid phase: A theoretical study including environment polarization effect

    NASA Astrophysics Data System (ADS)

    Santos, O. L.; Sabino, J. R.; Georg, H. C.; Fonseca, T. L.; Castro, M. A.

    2017-02-01

    The dipole moment, linear polarizability and first hyperpolarizability of the 3-methyl-4-nitropyridine-1-oxyde (POM) molecules in solid phase were determined by applying iteratively a supermolecule approach in combination with an electrostatic embedding scheme, in which the surrounding molecules are represented by point charges. It is found that the electrostatic interactions with the surrounding molecules lead to a quasi-vanishing molecular dipole moment for the unit cell, in concordance with the experiment. The environment polarization effect is mild for the linear polarizability but it can be marked for the first hyperpolarizability.

  8. 5,7-Dihydroxy-3,4,6-trimethoxyflavone inhibits intercellular adhesion molecule 1 and vascular cell adhesion molecule 1 via the Akt and nuclear factor-κB-dependent pathway, leading to suppression of adhesion of monocytes and eosinophils to bronchial epithelial cells

    PubMed Central

    Jung, Jireh; Ko, Su H; Yoo, Do Y; Lee, Jin Y; Kim, Yeong-Jeon; Choi, Seul M; Kang, Kyung K; Yoon, Ho J; Kim, Hyeyoung; Youn, Jeehee; Kim, Jung M

    2012-01-01

    5,7-Dihydroxy-3′,4′,6′-trimethoxyflavone (eupatilin), the active pharmacological ingredient from Artemisia asiatica Nakai (Asteraceae), is reported to have a variety of anti-inflammatory properties in intestinal epithelial cells. However, little information is known about the molecular mechanism of eupatilin-induced attenuation of bronchial epithelial inflammation. This study investigates the role of eupatilin in the adhesion of inflammatory cells such as monocytes and eosinophils to bronchial epithelial cells. Stimulation of a human bronchial epithelial cell line (BEAS-2B) with tumour necrosis factor-α (TNF-α) increased the expression of surface adhesion molecules, including intercellular adhesion molecule 1 (ICAM-1) and vascular cell adhesion molecule 1 (VCAM-1), in which eupatilin significantly inhibited the expression of those adhesion molecules in a dose-dependent manner. Eupatilin suppressed the TNF-α-induced activation of IκBα and nuclear factor-κB (NF-κB) signals in BEAS-2B cells. The IκB kinase (IKK) activation was also significantly reduced in eupatilin-pre-treated BEAS-2B and primary normal human bronchial epithelial (NHBE) cells. However, eupatilin did not influence AP-1 activity in TNF-α-stimulated cells. Suppression of NF-κB signalling induced by eupatilin resulted in the inhibition of the expression of adhesion molecules and the adhesion of monocytes and eosinophils to BEAS-2B cells. Furthermore, eupatilin suppressed the phosphorylation of Akt in TNF-α-stimulated BEAS-2B and NHBE cells, leading to down-regulation of NF-κB activation and adhesion molecule expression and finally to suppression of the inflammatory cell adhesion to epithelial cells. These results suggest that eupatilin can inhibit the adhesion of inflammatory cells to bronchial epithelial cells via a signalling pathway, including activation of Akt and NF-κB, as well as expression of adhesion molecules. PMID:22862554

  9. 5,7-Dihydroxy-3,4,6-trimethoxyflavone inhibits intercellular adhesion molecule 1 and vascular cell adhesion molecule 1 via the Akt and nuclear factor-κB-dependent pathway, leading to suppression of adhesion of monocytes and eosinophils to bronchial epithelial cells.

    PubMed

    Jung, Jireh; Ko, Su H; Yoo, Do Y; Lee, Jin Y; Kim, Yeong-Jeon; Choi, Seul M; Kang, Kyung K; Yoon, Ho J; Kim, Hyeyoung; Youn, Jeehee; Kim, Jung M

    2012-09-01

    5,7-Dihydroxy-3',4',6'-trimethoxyflavone (eupatilin), the active pharmacological ingredient from Artemisia asiatica Nakai (Asteraceae), is reported to have a variety of anti-inflammatory properties in intestinal epithelial cells. However, little information is known about the molecular mechanism of eupatilin-induced attenuation of bronchial epithelial inflammation. This study investigates the role of eupatilin in the adhesion of inflammatory cells such as monocytes and eosinophils to bronchial epithelial cells. Stimulation of a human bronchial epithelial cell line (BEAS-2B) with tumour necrosis factor-α (TNF-α) increased the expression of surface adhesion molecules, including intercellular adhesion molecule 1 (ICAM-1) and vascular cell adhesion molecule 1 (VCAM-1), in which eupatilin significantly inhibited the expression of those adhesion molecules in a dose-dependent manner. Eupatilin suppressed the TNF-α-induced activation of IκBα and nuclear factor-κB (NF-κB) signals in BEAS-2B cells. The IκB kinase (IKK) activation was also significantly reduced in eupatilin-pre-treated BEAS-2B and primary normal human bronchial epithelial (NHBE) cells. However, eupatilin did not influence AP-1 activity in TNF-α-stimulated cells. Suppression of NF-κB signalling induced by eupatilin resulted in the inhibition of the expression of adhesion molecules and the adhesion of monocytes and eosinophils to BEAS-2B cells. Furthermore, eupatilin suppressed the phosphorylation of Akt in TNF-α-stimulated BEAS-2B and NHBE cells, leading to down-regulation of NF-κB activation and adhesion molecule expression and finally to suppression of the inflammatory cell adhesion to epithelial cells. These results suggest that eupatilin can inhibit the adhesion of inflammatory cells to bronchial epithelial cells via a signalling pathway, including activation of Akt and NF-κB, as well as expression of adhesion molecules.

  10. The Evaluation of Lithium Hydride for Use in a Space Nuclear Reactor Shield, Including a Historical Perspective

    SciTech Connect

    D. Poeth

    2005-12-09

    LiH was one of the five primary shield materials the NRPCT intended to develop (along with beryllium, boron carbide, tungsten, and water) for potential Prometheus application. It was also anticipated that {sup 10}B metal would be investigated for feasibility at a low level of effort. LiH historically has been selected as a low mass, neutron absorption material for space shields (Systems for Nuclear Auxiliary Power (SNAP), Topaz, SP-100). Initial NRPCT investigations did not produce convincing evidence that LiH was desirable or feasible for a Prometheus mission due to material property issues (primarily swelling and hydrogen cover gas containment), and related thermal design complexity. Furthermore, if mass limits allowed, an option to avoid use of LiH was being contemplated to lower development costs and associated risks. However, LiH remains theoretically the most efficient neutron shield material per unit mass, and, with sufficient testing and development, could be an optimal material choice for future flights.

  11. Molecule nanoweaver

    DOEpatents

    Gerald, II; Rex, E [Brookfield, IL; Klingler, Robert J [Glenview, IL; Rathke, Jerome W [Homer Glen, IL; Diaz, Rocio [Chicago, IL; Vukovic, Lela [Westchester, IL

    2009-03-10

    A method, apparatus, and system for constructing uniform macroscopic films with tailored geometric assemblies of molecules on the nanometer scale. The method, apparatus, and system include providing starting molecules of selected character, applying one or more force fields to the molecules to cause them to order and condense with NMR spectra and images being used to monitor progress in creating the desired geometrical assembly and functionality of molecules that comprise the films.

  12. Time-resolved Coulomb-explosion imaging of nuclear wave-packet dynamics induced in diatomic molecules by intense few-cycle laser pulses

    SciTech Connect

    Bocharova, I. A.; Thumm, U.; Ray, D.; Cocke, C. L.; Alnaser, A. S.; Niederhausen, T.; Litvinyuk, I. V.

    2011-01-15

    We studied the nuclear dynamics in diatomic molecules (N{sub 2}, O{sub 2}, and CO) following their interaction with intense near-IR few-cycle laser pulses. Using Coulomb-explosion imaging in combination with the pump-probe approach, we mapped dissociation pathways of those molecules and their molecular ions. We identified all symmetric and asymmetric breakup channels for molecular ions up to N{sub 2}{sup 5+}, O{sub 2}{sup 4+}, and CO{sup 4+}. For each of those channels we measured the kinetic energy release (KER) spectra as a function of delay between the pump and probe pulses. For both N{sub 2} and O{sub 2} the asymmetric (3,1) channel is only observed for short (<20 fs) delays and completely disappears after that. We interpret this observation as a signature of electron localization taking place in dissociating molecular tri-cations when their internuclear separation reaches about 2.5 times the equilibrium bond length. This is a direct confirmation that electron localization plays an essential role in the universal mechanism of enhanced ionization in homonuclear diatomic molecules. Using classical and quantum mechanical simulations of the time-dependent KER spectra, we identify the pathways and intermediate states involved in the laser-induced dissociation of those molecules.

  13. Laser cooling of CaBr molecules and production of ultracold Br atoms: A theoretical study including spin-orbit coupling.

    PubMed

    Fu, Mingkai; Ma, Haitao; Cao, Jianwei; Bian, Wensheng

    2017-04-07

    Owing to the exciting potential applications of ultracold atoms and molecules in many fields, developing new cooling schemes has attracted great interests in recent years. Here, we investigate laser cooling of CaBr molecules and design a photonic scheme for the production of ultracold Br atoms using the highly accurate ab initio and dynamical methods. We find that the AΠ1/22(ν(')=0)→X(2)Σ1/2(+)(ν=0) transition for CaBr features a large vibrational branching ratio, a significant photon-scattering rate, and no intermediate electronic-state interference, indicating that the ultracold CaBr could be produced through a three-laser cooling scheme. Moreover, an efficient four-pulse excitation scheme from the ground rovibrational level of the cooled CaBr molecules is proposed to yield ultracold Br atoms, in which a few spin-orbit excited states are utilized as the intermediate states. The importance of the spin-orbit coupling is underscored in this work.

  14. Charge and Nuclear Dynamics Induced by Deep Inner-Shell Multiphoton Ionization of CH3I Molecules by Intense X-ray Free-Electron Laser Pulses.

    PubMed

    Motomura, Koji; Kukk, Edwin; Fukuzawa, Hironobu; Wada, Shin-ichi; Nagaya, Kiyonobu; Ohmura, Satoshi; Mondal, Subhendu; Tachibana, Tetsuya; Ito, Yuta; Koga, Ryosuke; Sakai, Tsukasa; Matsunami, Kenji; Rudenko, Artem; Nicolas, Christophe; Liu, Xiao-Jing; Miron, Catalin; Zhang, Yizhu; Jiang, Yuhai; Chen, Jianhui; Anand, Mailam; Kim, Dong Eon; Tono, Kensuke; Yabashi, Makina; Yao, Makoto; Ueda, Kiyoshi

    2015-08-06

    In recent years, free-electron lasers operating in the true X-ray regime have opened up access to the femtosecond-scale dynamics induced by deep inner-shell ionization. We have investigated charge creation and transfer dynamics in the context of molecular Coulomb explosion of a single molecule, exposed to sequential deep inner-shell ionization within an ultrashort (10 fs) X-ray pulse. The target molecule was CH3I, methane sensitized to X-rays by halogenization with a heavy element, iodine. Time-of-flight ion spectroscopy and coincident ion analysis was employed to investigate, via the properties of the atomic fragments, single-molecule charge states of up to +22. Experimental findings have been compared with a parametric model of simultaneous Coulomb explosion and charge transfer in the molecule. The study demonstrates that including realistic charge dynamics is imperative when molecular Coulomb explosion experiments using short-pulse facilities are performed.

  15. Theoretical Evaluation of [V(IV)(α-C3S5)3](2-) as Nuclear-Spin-Sensitive Single-Molecule Spin Transistor.

    PubMed

    Cardona-Serra, S; Gaita-Ariño, A; Stamenova, M; Sanvito, S

    2017-07-06

    In a straightforward application of molecular nanospintronics to quantum computing, single-molecule spin transistors can be used to measure nuclear spin qubits. Conductance jumps accompany electronic spin flips at the so-called anticrossings between energy levels, which take place only at specific magnetic fields determined by the nuclear spin state. To date, the only molecular hardware employed for this technique has been the terbium(III) bis(phthalocyaninato) complex. Here we explore theoretically whether a similar behavior is expected for a highly stable molecular spin qubit, the vanadium tris-dithiolate complex [V(IV)(α-C3S5)3](2-). We consider such a molecule between two gold electrodes and determine the spin-dependent conductance. We verify that the transport channel in experimental conditions does not overlap with the occupied spin orbitals, indicating that the spin states may survive in the conduction regime. We validate the robustness of the theoretical methodology by studying two chemically related vanadium complexes and offer some criteria to guide the experiments.

  16. Ultrafast x-ray-induced nuclear dynamics in diatomic molecules using femtosecond x-ray / x-ray pump-probe spectroscopy

    SciTech Connect

    Lehmann, C. S.; Picon, A.; Bostedy, C.; Rudenko, A; Marinelli, A.; Moonshiram, D.; Osipov, T; Rolles, D; Berrah, N; Bomme, C; Bucher, M.; Doumy, G.; Ho, P. J.; Kanter, E.P.; Krassig, B.; March, A. M.; Young, L.; Pratt, S. T.; Southworth, S.H.

    2016-07-26

    The availability at x-ray free electron lasers of generating two intense, femtosecond x-ray pulses with controlled time delay opens the possibility of performing time-resolved experiments for x-ray induced phenomena. We have applied this capability to molecular dynamics. In diatomic molecules composed of low-Z elements, K-shell ionization creates a core-hole state in which the main decay is an Auger process involving two electrons in the valence shell. After Auger decay, the nuclear wavepackets of the transient two-valence-hole states continue evolving on the femtosecond timescale, leading either to separated atomic ions or long-lived quasi-bound states. By using an x-ray pump and an x-ray probe pulse tuned above the K-shell ionization threshold of the nitrogen molecule, we are able to observe ion dissociation in progress by measuring the time-dependent kinetic energy releases of different breakup channels. We simulated the measurements on N2 with a molecular dynamics model that accounts for K-shell ionization, Auger decay, and time evolution of the nuclear wavepackets. In addition to explaining the time-dependent feature in the measured kinetic energy release distributions from the dissociative states, the simulation also reveals the contributions of quasi-bound states.

  17. Nonadiabatic Evolution of Electronic States by Electron Nuclear Dynamics Theory: Application to Atom-Molecule Scattering Problems.

    NASA Astrophysics Data System (ADS)

    Hagelberg, Frank

    2004-03-01

    In this contribution, we address the problem how to determine accurately the nonadiabatic content of any given dynamic process involving molecular motion. More specifically, we generate a dynamic electronic wave function using Electron Nuclear Dynamics (END) theory^2 and cast this wave function into the language of electronic excitations. This is achieved by adiabatic transport of an electronic basis along the classical nuclear trajectories of the studied molecular system. This basis is chosen as the static UHF molecular ground state determinant of the system in conjunction with all determinants that arise from the ground state by single, double and triple substitutions. Projecting the dynamic wave function into this basis, we arrive at a natural distinction between adiabatic and nonadiabatic components of the motion considered. We will discuss this concept by the examples of various scattering problems, among them the interaction of proton projectiles with methylene targets. ^2E. Deumens et al., Rev. Mod. Phys. 1994, 66, 917.

  18. Alpha clustering and nuclear molecules in8Be, 12C, 16O, 20Ne, 24Mg, and32S

    NASA Astrophysics Data System (ADS)

    Royer, G.; Eudes, P.

    2017-06-01

    Within a liquid drop model the energy of the12C,16O,20Ne,24Mg and32S 4n-nuclei has been calculated within different configurations of α-molecules : linear chain, triangle, square, tetrahedron, pentagon, trigonal bipyramid, square pyramid, hexagon, octahedron, octagon and cube. The potential barriers governing the decay and entrance channels via α emission or absorption as well as the potential barriers of other possible binary and ternary reactions have been compared. The rms radii of the linear chains do not correspond to the experimental rms radii of the ground states. The binding energies of the three-dimensional molecules at the nascent point of the fragments are higher than the ones of the planar configurations. The A-4 daughter plus α particle configurations have always the lowest potential energy.

  19. Structural characterization of new defective molecules in poly(amidoamide) dendrimers by combining mass spectrometry and nuclear magnetic resonance.

    PubMed

    Tintaru, Aura; Ungaro, Rémi; Liu, Xiaoxiuan; Chen, Chao; Giordano, Laurent; Peng, Ling; Charles, Laurence

    2015-01-01

    A new side-reaction occurring during divergent synthesis of PAMAM dendrimers (generations G0-G2) was revealed by mass spectrometric detection of defective molecules with a net gain of a single carbon atom as compared to expected compounds. Combining MS/MS experiments performed on different electrosprayed precursor ions (protonated molecules and lithiated adducts) with NMR analyses allowed the origin of these by-products to be elucidated. Modification of one ethylenediamine end-group of perfect dendrimers into a cyclic imidazolidine moiety was induced by formaldehyde present at trace level in the methanol solvent used as the synthesis medium. Dendrimers studied here were purposely constructed from a triethanolamine core to make them more flexible, as compared to NH3- or ethylenediamine-core PAMAM, and hence improve their interaction with DNA. Occurrence of this side-reaction would be favored by the particular flexibility of the dendrimer branches.

  20. WNT-C59, a Small-Molecule WNT Inhibitor, Efficiently Induces Anterior Cortex That Includes Cortical Motor Neurons From Human Pluripotent Stem Cells.

    PubMed

    Motono, Makoto; Ioroi, Yoshihiko; Ogura, Takenori; Takahashi, Jun

    2016-04-01

    The recapitulation of human neural development in a controlled, defined manner from pluripotent stem cells (PSCs) has considerable potential for studies of human neural development, circuit formation and function, and the construction of in vitro models of neurological diseases. The inhibition of Wnt signaling, often by the recombinant protein DKK1, is important for the induction of cortical neurons. Here, we report a novel differentiation method using a small-molecule WNT inhibitor, WNT-C59 (C59), to efficiently induce human anterior cortex. We compared two types of small molecules, C59 and XAV939 (XAV), as substitutes for DKK1 to induce cortical neurons from PSCs in serum-free embryoid body-like aggregate culture. DKK1 and XAV inhibited only the canonical pathway of Wnt signaling, whereas C59 inhibited both the canonical and noncanonical pathways. C59 efficiently induced CTIP2+/COUP-TF1- cells, which are characteristic of the cells found in the anterior cortex. In addition, when grafted into the cortex of adult mice, the C59-induced cells showed abundant axonal fiber extension toward the spinal cord. These results raise the possibility of C59 contributing to cell replacement therapy for motor neuron diseases or insults. For a cell therapy against damaged corticospinal tract caused by neurodegenerative diseases or insults, cortical motor neurons are needed. Currently, their induction from pluripotent stem cells is considered very promising; however, an efficient protocol to induce motor neurons is not available. For efficient induction of anterior cortex, where motor neurons are located, various WNT inhibitors were investigated. It was found that one of them could induce anterior cortical cells efficiently. In addition, when grafted into the cortex of adult mice, the induced cells showed more abundant axonal fiber extension toward spinal cord. These results raise the possibility that this inhibitor contributes to a cell-replacement therapy for motor neuron

  1. Attempts at Using Iamcalc to Analyze Low Frequency Rotational Spectra of Molecules with Internal Rotation and Nuclear Spins

    NASA Astrophysics Data System (ADS)

    Dewberry, Christopher T.; Cooke, Stephen A.

    2010-06-01

    Recent progress in the fitting and analyses of simple methyl rotors to simultaneously account for internal rotation and nuclear hyperfine terms will be presented. The analyses have been attempted using Herb Pickett's IAMCALC program which acts as a ``front end" for the powerful SPFIT/SPCAT software. Progress has been made by simply appending hyperfine parameters to an IAMCALC-prepared SPFIT input file. This work has been prompted by our recent high resolution spectral measurements in the 1 - 21 GHz region on species such as methanol and methyl nitrite. Data will be presented together with comments on the validity of the fitting approach.

  2. Interstellar molecules

    NASA Technical Reports Server (NTRS)

    Townes, C. H.

    1976-01-01

    Progress in the discovery and study of interstellar molecules is summarized. The 36 molecular species thus far identified in interstellar space are listed in several groups which include simple hydrides, oxides, and sulfides, various derivatives of ammonia, molecules involving linear carbon chains, cyanides, and molecules related in structure to formaldehyde, alcohols, or ethers. Several free radicals are described, the discovery of molecules in external galaxies is discussed, and possible mechanisms for molecular formation are noted. Methods for examining relative isotopic abundances by measuring molecules in interstellar clouds are outlined, mechanisms for the excitation of interstellar molecules are reviewed, and values are presented for the C-12/C-13 abundance ratio in a number of interstellar clouds. The detection of interstellar masers is discussed along with pumping mechanisms and masing transitions in H2CO, CH, OH, and SiO. The nature of dense interstellar clouds is examined in terms of several simple and complex cloud models, with emphasis on multiple condensation models.

  3. Relativistic calculation of nuclear magnetic shielding tensor using the regular approximation to the normalized elimination of the small component. III. Introduction of gauge-including atomic orbitals and a finite-size nuclear model

    NASA Astrophysics Data System (ADS)

    Hamaya, S.; Maeda, H.; Funaki, M.; Fukui, H.

    2008-12-01

    The relativistic calculation of nuclear magnetic shielding tensors in hydrogen halides is performed using the second-order regular approximation to the normalized elimination of the small component (SORA-NESC) method with the inclusion of the perturbation terms from the metric operator. This computational scheme is denoted as SORA-Met. The SORA-Met calculation yields anisotropies, Δσ =σ∥-σ⊥, for the halogen nuclei in hydrogen halides that are too small. In the NESC theory, the small component of the spinor is combined to the large component via the operator σ⃗ṡπ⃗U/2c, in which π⃗=p⃗+A⃗, U is a nonunitary transformation operator, and c ≅137.036 a.u. is the velocity of light. The operator U depends on the vector potential A⃗ (i.e., the magnetic perturbations in the system) with the leading order c-2 and the magnetic perturbation terms of U contribute to the Hamiltonian and metric operators of the system in the leading order c-4. It is shown that the small Δσ for halogen nuclei found in our previous studies is related to the neglect of the U(0,1) perturbation operator of U, which is independent of the external magnetic field and of the first order with respect to the nuclear magnetic dipole moment. Introduction of gauge-including atomic orbitals and a finite-size nuclear model is also discussed.

  4. Relativistic calculation of nuclear magnetic shielding tensor using the regular approximation to the normalized elimination of the small component. III. Introduction of gauge-including atomic orbitals and a finite-size nuclear model.

    PubMed

    Hamaya, S; Maeda, H; Funaki, M; Fukui, H

    2008-12-14

    The relativistic calculation of nuclear magnetic shielding tensors in hydrogen halides is performed using the second-order regular approximation to the normalized elimination of the small component (SORA-NESC) method with the inclusion of the perturbation terms from the metric operator. This computational scheme is denoted as SORA-Met. The SORA-Met calculation yields anisotropies, Delta sigma = sigma(parallel) - sigma(perpendicular), for the halogen nuclei in hydrogen halides that are too small. In the NESC theory, the small component of the spinor is combined to the large component via the operator sigma x piU/2c, in which pi = p + A, U is a nonunitary transformation operator, and c approximately = 137.036 a.u. is the velocity of light. The operator U depends on the vector potential A (i.e., the magnetic perturbations in the system) with the leading order c(-2) and the magnetic perturbation terms of U contribute to the Hamiltonian and metric operators of the system in the leading order c(-4). It is shown that the small Delta sigma for halogen nuclei found in our previous studies is related to the neglect of the U(0,1) perturbation operator of U, which is independent of the external magnetic field and of the first order with respect to the nuclear magnetic dipole moment. Introduction of gauge-including atomic orbitals and a finite-size nuclear model is also discussed.

  5. Complexation of the vulcanization accelerator tetramethylthiuram disulfide and related molecules with zinc compounds including zinc oxide clusters (Zn4O4).

    PubMed

    Steudel, Ralf; Steudel, Yana; Wong, Ming Wah

    2008-01-01

    Zinc chemicals are used as activators in the vulcanization of organic polymers with sulfur to produce elastic rubbers. In this work, the reactions of Zn(2+), ZnMe(2), Zn(OMe)(2), Zn(OOCMe)(2), and the heterocubane cluster Zn(4)O(4) with the vulcanization accelerator tetramethylthiuram disulfide (TMTD) and with the related radicals and anions Me(2)NCS(2)(*), Me(2)NCS(3)(*), Me(2)NCS(2)(-), and Me(2)NCS(3)(-) have been studied by quantum chemical methods at the MP2/6-31+G(2df,p)//B3LYP/6-31+G* level of theory. More than 35 zinc complexes have been structurally characterized and the energies of formation from their components calculated for the first time. The binding energy of TMTD as a bidendate ligand increases in the order ZnMe(2)molecule at the S-S bond on reaction with the Zn(4)O(4) cluster is predicted to be strongly exothermic, in sharp contrast to the endothermic S-S bond dissociation of the free molecule. The same holds for tetramethylthiuram trisulfide (TMTT). Surprisingly, the resulting complexes contain Zn-S as well as S-O bonds. The Zn(4)O(4) nanocluster serves here as a model for bulk zinc oxide used as an activator in rubber vulcanization by sulfur. The further uptake of sulfur atoms by the various complexes from S(8) or TMTD with formation of species derived from the radical Me(2)NCS(3)(*) or the trithiocarbamate anion Me(2)NCS(3)(-) is endothermic for mono- and dinuclear zinc dithiocarbamate (dtc) complexes such as [Zn(dtc)(2)] and [Zn(2)(dtc)(4)], but exothermic in the case of polynuclear zinc oxide species containing bridging ligands as in [Zn(4)O(4)(mu-S(2)CNMe(2))] and [Zn(4)O(4)(mu-dtc)]. Therefore, zinc oxide as a polynuclear species is predicted to promote the formation of trisulfido complexes, which are generally assumed to serve as catalysts for the transfer of

  6. Activation of nuclear factor-kappa B and cell adhesion molecule mRNA expression in duodenal mucosa of dogs with lymphocytic-plasmacytic enteritis.

    PubMed

    Okanishi, Hiroki; Kabeya, Hidenori; Maruyama, Soichi; Kagawa, Yumiko; Watari, Toshihiro

    2013-08-15

    Lymphocytic-plasmacytic enteritis (LPE) is the most common form of inflammatory bowel disease (IBD) affecting the canine small intestine; however, the molecular basis of the pathogenesis remains unclear. It has recently been hypothesized that the primary defect is impaired innate immune function, as is the case for human IBD. Nuclear factor-kappa B (NFkappaB) plays a central role in innate immunity, and is a major transcriptional regulator of several proinflammatory cytokines, pattern recognition receptors (PRRs) such as toll-like receptors (TLRs), nucleotide-binding oligomerization domain-like receptors and cell adhesion molecules (CAMs). The purpose of this study was to evaluate, in the duodenal mucosa of 21 dogs with LPE and 8 control dogs, the degree of NFkappaB activity and the mRNA expression of two selected cytokines, nucleotide oligomerization domain two (NOD2) receptor and three selected CAMs, all of which are regulated by NFkappaB, using the electrophoretic mobility shift assay and real-time reverse transcription PCR. NFkappaB binding activity was significantly higher in the inflamed duodenal mucosa of the LPE dogs as compared to healthy controls. Furthermore, expression of mRNA for intercellular cell adhesion molecule 1 (ICAM-1) and mucosal addressin cell adhesion molecule 1 (MAdCAM-1) was significantly higher and vascular cell adhesion molecule 1 (VCAM-1) mRNA significantly lower in LPE dogs than in healthy controls. However, there was no significant difference in the mRNA levels for TNFα, IL1β and NOD2 between the two groups. These results suggest that NFkappaB and CAMs may play important roles in the pathogenesis of canine LPE. Copyright © 2013 Elsevier B.V. All rights reserved.

  7. Ab initio study of the positronation of the CaO and SrO molecules including calculation of annihilation rates.

    PubMed

    Buenker, Robert J; Liebermann, Heinz-Peter

    2012-07-15

    Ab initio multireference single- and double-excitation configuration interaction calculations have been performed to compute potential curves for ground and excited states of the CaO and SrO molecules and their positronic complexes, e(+)CaO, and e(+)SrO. The adiabatic dissociation limit for the (2)Σ(+) lowest states of the latter systems consists of the positive metal ion ground state (M(+)) and the OPs complex (e(+)O(-)), although the lowest energy limit is thought to be e(+)M + O. Good agreement is found between the calculated and experimental spectroscopic constants for the neutral diatomics wherever available. The positron affinity of the closed-shell X (1)Σ(+) ground states of both systems is found to lie in the 0.16-0.19 eV range, less than half the corresponding values for the lighter members of the alkaline earth monoxide series, BeO and MgO. Annihilation rates (ARs) have been calculated for all four positronated systems for the first time. The variation with bond distance is generally similar to what has been found earlier for the alkali monoxide series of positronic complexes, falling off gradually from the OPs AR value at their respective dissociation limits. The e(+)SrO system shows some exceptional behavior, however, with its AR value reaching a minimum at a relatively large bond distance and then rising to more than twice the OPs value close to its equilibrium distance.

  8. Organic–inorganic binary mixture matrix for comprehensive laser-desorption ionization mass spectrometric analysis and imaging of medium-size molecules including phospholipids, glycerolipids, and oligosaccharides

    SciTech Connect

    Feenstra, Adam D.; O'Neill, Kelly C.; Yagnik, Gargey B.; Lee, Young Jin

    2016-10-13

    Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) is a widely adopted, versatile technique, especially in high-throughput analysis and imaging. However, matrix-dependent selectivity of analytes is often a severe limitation. In this work, a mixture of organic 2,5-dihydroxybenzoic acid and inorganic Fe3O4 nanoparticles is developed as a binary MALDI matrix to alleviate the well-known issue of triacylglycerol (TG) ion suppression by phosphatidylcholine (PC). In application to lipid standards and maize seed cross-sections, the binary matrix not only dramatically reduced the ion suppression of TG, but also efficiently desorbed and ionized a wide variety of lipids such as cationic PC, anionic phosphatidylethanolamine (PE) and phosphatidylinositol (PI), and neutral digalactosyldiacylglycerol (DGDG). The binary matrix was also very efficient for large polysaccharides, which were not detected by either of the individual matrices. As a result, the usefulness of the binary matrix is demonstrated in MS imaging of maize seed sections, successfully visualizing diverse medium-size molecules and acquiring high-quality MS/MS spectra for these compounds.

  9. Hyaluronic Acid--an "Old" Molecule with "New" Functions: Biosynthesis and Depolymerization of Hyaluronic Acid in Bacteria and Vertebrate Tissues Including during Carcinogenesis.

    PubMed

    Tsepilov, R N; Beloded, A V

    2015-09-01

    Hyaluronic acid is an evolutionarily ancient molecule commonly found in vertebrate tissues and capsules of some bacteria. Here we review modern data regarding structure, properties, and biological functions of hyaluronic acid in mammals and Streptococcus spp. bacteria. Various aspects of biogenesis and degradation of hyaluronic acid are discussed, biosynthesis and degradation metabolic pathways for glycosaminoglycan together with involved enzymes are described, and vertebrate and bacterial hyaluronan synthase genes are characterized. Special attention is given to the mechanisms underlying the biological action of hyaluronic acid as well as the interaction between polysaccharide and various proteins. In addition, all known signaling pathways involving hyaluronic acid are outlined. Impaired hyaluronic acid metabolism, changes in biopolymer molecular weight, hyaluronidase activity, and enzyme isoforms often accompany carcinogenesis. The interaction between cells and hyaluronic acid from extracellular matrix that may be important during malignant change is discussed. An expected role for high molecular weight hyaluronic acid in resistance of naked mole rat to oncologic diseases and the protective role of hyaluronic acid in bacteria are discussed.

  10. Diversity of Dicotyledenous-Infecting Geminiviruses and Their Associated DNA Molecules in Southern Africa, Including the South-West Indian Ocean Islands

    PubMed Central

    Rey, Marie E. C.; Ndunguru, Joseph; Berrie, Leigh C.; Paximadis, Maria; Berry, Shaun; Cossa, Nurbibi; Nuaila, Valter N.; Mabasa, Ken G.; Abraham, Natasha; Rybicki, Edward P.; Martin, Darren; Pietersen, Gerhard; Esterhuizen, Lindy L.

    2012-01-01

    The family Geminiviridae comprises a group of plant-infecting circular ssDNA viruses that severely constrain agricultural production throughout the temperate regions of the world, and are a particularly serious threat to food security in sub-Saharan Africa. While geminiviruses exhibit considerable diversity in terms of their nucleotide sequences, genome structures, host ranges and insect vectors, the best characterised and economically most important of these viruses are those in the genus Begomovirus. Whereas begomoviruses are generally considered to be either monopartite (one ssDNA component) or bipartite (two circular ssDNA components called DNA-A and DNA-B), many apparently monopartite begomoviruses are associated with additional subviral ssDNA satellite components, called alpha- (DNA-αs) or betasatellites (DNA-βs). Additionally, subgenomic molecules, also known as defective interfering (DIs) DNAs that are usually derived from the parent helper virus through deletions of parts of its genome, are also associated with bipartite and monopartite begomoviruses. The past three decades have witnessed the emergence and diversification of various new begomoviral species and associated DI DNAs, in southern Africa, East Africa, and proximal Indian Ocean islands, which today threaten important vegetable and commercial crops such as, tobacco, cassava, tomato, sweet potato, and beans. This review aims to describe what is known about these viruses and their impacts on sustainable production in this sensitive region of the world. PMID:23170182

  11. Diversity of dicotyledenous-infecting geminiviruses and their associated DNA molecules in southern Africa, including the South-west Indian ocean islands.

    PubMed

    Rey, Marie E C; Ndunguru, Joseph; Berrie, Leigh C; Paximadis, Maria; Berry, Shaun; Cossa, Nurbibi; Nuaila, Valter N; Mabasa, Ken G; Abraham, Natasha; Rybicki, Edward P; Martin, Darren; Pietersen, Gerhard; Esterhuizen, Lindy L

    2012-09-01

    The family Geminiviridae comprises a group of plant-infecting circular ssDNA viruses that severely constrain agricultural production throughout the temperate regions of the world, and are a particularly serious threat to food security in sub-Saharan Africa. While geminiviruses exhibit considerable diversity in terms of their nucleotide sequences, genome structures, host ranges and insect vectors, the best characterised and economically most important of these viruses are those in the genus Begomovirus. Whereas begomoviruses are generally considered to be either monopartite (one ssDNA component) or bipartite (two circular ssDNA components called DNA-A and DNA-B), many apparently monopartite begomoviruses are associated with additional subviral ssDNA satellite components, called alpha- (DNA-αs) or betasatellites (DNA-βs). Additionally, subgenomic molecules, also known as defective interfering (DIs) DNAs that are usually derived from the parent helper virus through deletions of parts of its genome, are also associated with bipartite and monopartite begomoviruses. The past three decades have witnessed the emergence and diversification of various new begomoviral species and associated DI DNAs, in southern Africa, East Africa, and proximal Indian Ocean islands, which today threaten important vegetable and commercial crops such as, tobacco, cassava, tomato, sweet potato, and beans. This review aims to describe what is known about these viruses and their impacts on sustainable production in this sensitive region of the world.

  12. Organic–inorganic binary mixture matrix for comprehensive laser-desorption ionization mass spectrometric analysis and imaging of medium-size molecules including phospholipids, glycerolipids, and oligosaccharides

    DOE PAGES

    Feenstra, Adam D.; Ames Lab., Ames, IA; O'Neill, Kelly C.; ...

    2016-10-13

    Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) is a widely adopted, versatile technique, especially in high-throughput analysis and imaging. However, matrix-dependent selectivity of analytes is often a severe limitation. In this work, a mixture of organic 2,5-dihydroxybenzoic acid and inorganic Fe3O4 nanoparticles is developed as a binary MALDI matrix to alleviate the well-known issue of triacylglycerol (TG) ion suppression by phosphatidylcholine (PC). In application to lipid standards and maize seed cross-sections, the binary matrix not only dramatically reduced the ion suppression of TG, but also efficiently desorbed and ionized a wide variety of lipids such as cationic PC, anionic phosphatidylethanolamine (PE)more » and phosphatidylinositol (PI), and neutral digalactosyldiacylglycerol (DGDG). The binary matrix was also very efficient for large polysaccharides, which were not detected by either of the individual matrices. As a result, the usefulness of the binary matrix is demonstrated in MS imaging of maize seed sections, successfully visualizing diverse medium-size molecules and acquiring high-quality MS/MS spectra for these compounds.« less

  13. Intra-nuclear mobility and target search mechanisms of transcription factors: a single-molecule perspective on gene expression.

    PubMed

    Normanno, Davide; Dahan, Maxime; Darzacq, Xavier

    2012-06-01

    Precise expression of specific genes in time and space is at the basis of cellular viability as well as correct development of organisms. Understanding the mechanisms of gene regulation is fundamental and still one of the great challenges for biology. Gene expression is regulated also by specific transcription factors that recognize and bind to specific DNA sequences. Transcription factors dynamics, and especially the way they sample the nucleoplasmic space during the search for their specific target in the genome, are a key aspect for regulation and it has been puzzling researchers for forty years. The scope of this review is to give a state-of-the-art perspective over the intra-nuclear mobility and the target search mechanisms of specific transcription factors at the molecular level. Going through the seminal biochemical experiments that have raised the first questions about target localization and the theoretical grounds concerning target search processes, we describe the most recent experimental achievements and current challenges in understanding transcription factors dynamics and interactions with DNA using in vitro assays as well as in live prokaryotic and eukaryotic cells. This article is part of a Special Issue entitled: Nuclear Transport and RNA Processing. Copyright © 2012 Elsevier B.V. All rights reserved.

  14. Cytoplasmic-nuclear trafficking of G1/S cell cycle molecules and adult human β-cell replication: a revised model of human β-cell G1/S control.

    PubMed

    Fiaschi-Taesch, Nathalie M; Kleinberger, Jeffrey W; Salim, Fatimah G; Troxell, Ronnie; Wills, Rachel; Tanwir, Mansoor; Casinelli, Gabriella; Cox, Amy E; Takane, Karen K; Srinivas, Harish; Scott, Donald K; Stewart, Andrew F

    2013-07-01

    Harnessing control of human β-cell proliferation has proven frustratingly difficult. Most G1/S control molecules, generally presumed to be nuclear proteins in the human β-cell, are in fact constrained to the cytoplasm. Here, we asked whether G1/S molecules might traffic into and out of the cytoplasmic compartment in association with activation of cell cycle progression. Cdk6 and cyclin D3 were used to drive human β-cell proliferation and promptly translocated into the nucleus in association with proliferation. In contrast, the cell cycle inhibitors p15, p18, and p19 did not alter their location, remaining cytoplasmic. Conversely, p16, p21, and p27 increased their nuclear frequency. In contrast once again, p57 decreased its nuclear frequency. Whereas proliferating β-cells contained nuclear cyclin D3 and cdk6, proliferation generally did not occur in β-cells that contained nuclear cell cycle inhibitors, except p21. Dynamic cytoplasmic-nuclear trafficking of cdk6 was confirmed using green fluorescent protein-tagged cdk6 and live cell imaging. Thus, we provide novel working models describing the control of cell cycle progression in the human β-cell. In addition to known obstacles to β-cell proliferation, cytoplasmic-to-nuclear trafficking of G1/S molecules may represent an obstacle as well as a therapeutic opportunity for human β-cell expansion.

  15. Crystal structures of tiotropium bromide and its monohydrate in view of combined solid-state nuclear magnetic resonance and gauge-including projector-augmented wave studies.

    PubMed

    Pindelska, Edyta; Szeleszczuk, Lukasz; Pisklak, Dariusz Maciej; Majka, Zbigniew; Kolodziejski, Waclaw

    2015-07-01

    Tiotropium bromide is an anticholinergic bronchodilator used in the management of chronic obstructive pulmonary disease. The crystal structures of this compound and its monohydrate have been previously solved and published. However, in this paper, we showed that those structures contain some major errors. Our methodology based on combination of the solid-state nuclear magnetic resonance (NMR) spectroscopy and quantum mechanical gauge-including projector-augmented wave (GIPAW) calculations of NMR shielding constants enabled us to correct those errors and obtain reliable structures of the studied compounds. It has been proved that such approach can be used not only to perform the structural analysis of a drug substance and to identify its polymorphs, but also to verify and optimize already existing crystal structures.

  16. A study of the water molecule using frequency control over nuclear dynamics in resonant X-ray scattering.

    PubMed

    Vaz da Cruz, Vinícius; Ertan, Emelie; Couto, Rafael C; Eckert, Sebastian; Fondell, Mattis; Dantz, Marcus; Kennedy, Brian; Schmitt, Thorsten; Pietzsch, Annette; Guimarães, Freddy F; Ågren, Hans; Gel'mukhanov, Faris; Odelius, Michael; Föhlisch, Alexander; Kimberg, Victor

    2017-03-29

    In this combined theoretical and experimental study we report a full analysis of the resonant inelastic X-ray scattering (RIXS) spectra of H2O, D2O and HDO. We demonstrate that electronically-elastic RIXS has an inherent capability to map the potential energy surface and to perform vibrational analysis of the electronic ground state in multimode systems. We show that the control and selection of vibrational excitation can be performed by tuning the X-ray frequency across core-excited molecular bands and that this is clearly reflected in the RIXS spectra. Using high level ab initio electronic structure and quantum nuclear wave packet calculations together with high resolution RIXS measurements, we discuss in detail the mode coupling, mode localization and anharmonicity in the studied systems.

  17. Synthesis and Exploratory Catalysis of 3d Metals: Group-Transfer Reactions, and the Activation and Functionalization of Small Molecules Including Greenhouse Gases

    SciTech Connect

    Mindiola, Daniel J.

    2014-05-07

    Our work over the past three years has resulted in the development of electron rich and low-coordinate vanadium fragments, molecular nitrides of vanadium and parent imide systems of titanium, and the synthesis of phosphorus containing molecules of the 3d transition metal series. Likewise, with financial support from BES Division in DOE (DE-FG02-07ER15893), we now completed the full characterization of the first single molecular magnet (SMM) of Fe(III). We demonstrated that this monomeric form of Fe(III) has an unusual slow relaxation of the magnetization under zero applied field. To make matters more interesting, this system also undergoes a rare example of an intermediate to high-spin transition (an S = 3/2 to S = 5/2 transition). In 2010 we reported the synthesis of the first neutral and low-coordinate vanadium complexes having the terminal nitride functionality. We have now completed a full study to understand formation of the nitride ligand from the metastable azide precursor, and have also explored the reactivity of the nitride ligand in the context of incomplete and complete N-atom transfer. During the 2010-2013 period we also discovered a facile approach to assemble low-coordinate and low-valent vanadium(II) complexes and exploit their multielectron chemistry ranging from 1-3 electrons. Consequently, we can now access 3d ligand frameworks such as cyclo-P3 (and its corresponding radical anion), nitride radical anions and cations, low-coordinate vanadium oxo’s, and the first example of a vanadium thionitrosyl complex. A cis-divacant iron(IV) imido having some ligand centered radical has been also discovered, and we are in the process of elucidating its electronic structure (in particular the sign of zero field splitting and the origin of its magnitude), bonding and reactivity. We have also revisited some paramagnetic and classic metallocene compounds with S >1/2 ground states in order to understand their reactivity patterns and electronic structure. Lastly

  18. Enneanuclear [Ni6Ln3] Cages: [Ln(III)3] Triangles Capping [Ni(II)6] Trigonal Prisms Including a [Ni6Dy3] Single-Molecule Magnet.

    PubMed

    Canaj, Angelos B; Tzimopoulos, Demetrios I; Siczek, Milosz; Lis, Tadeusz; Inglis, Ross; Milios, Constantinos J

    2015-07-20

    The use of (2-(β-naphthalideneamino)-2-hydroxymethyl-1-propanol) ligand, H3L, in Ni/Ln chemistry has led to the isolation of three new isostructural [Ni(II)6Ln(III)3] metallic cages. More specifically, the reaction of Ni(ClO4)2·6H2O, the corresponding lanthanide nitrate salt, and H3L in MeCN, under solvothermal conditions in the presence of NEt3, led to the isolation of three complexes with the formulas [Ni6Gd3(OH)6(HL)6(NO3)3]·5.75MeCN·2Et2O·1.5H2O (1·5.75MeCN·2Et2O·1.5H2O), [Ni6Dy3(OH)6(HL)6(NO3)3]·2MeCN·2.7Et2O·2.4H2O (2·2MeCN·2.7Et2O·2.4H2O), and [Ni6Er3(OH)6(HL)6(NO3)3]·5.75MeCN·2Et2O·1.5H2O (3·5.75MeCN·2Et2O·1.5H2O). The structure of all three clusters describes a [Ln(III)3] triangle capping a [Ni(II)6] trigonal prism. Direct current magnetic susceptibility studies in the 5-300 K range for complexes 1-3 reveal the different nature of the magnetic interactions within the clusters: dominant antiferromagnetic exchange interactions for the Dy(III) and Er(III) analogues and dominant ferromagnetic interactions for the Gd(III) example. Alternating current magnetic susceptibility measurements under zero external dc field displayed fully formed temperature- and frequency-dependent out-of-phase peaks for the [Ni(II)6Dy(III)3] analogue, establishing its single molecule magnetism behavior with Ueff = 24 K.

  19. Benchmark calculations on the nuclear quadrupole-coupling parameters for open-shell molecules using non-relativistic and scalar-relativistic coupled-cluster methods

    SciTech Connect

    Cheng, Lan

    2015-08-14

    Quantum-chemical computations of nuclear quadrupole-coupling parameters for 24 open-shell states of small molecules based on non-relativistic and spin-free exact two-component (SFX2C) relativistic equation-of-motion coupled-cluster (EOM-CC) as well as spin-orbital-based restricted open-shell Hartree-Fock coupled-cluster (ROHF-CC) methods are reported. Relativistic effects, the performance of the EOM-CC and ROHF-CC methods for treating electron correlation, as well as basis-set convergence have been carefully analyzed. Consideration of relativistic effects is necessary for accurate calculations on systems containing third-row (K-Kr) and heavier elements, as expected, and the SFX2C approach is shown to be a useful cost-effective option here. Further, it is demonstrated that the EOM-CC methods constitute flexible and accurate alternatives to the ROHF-CC methods in the calculations of nuclear quadrupole-coupling parameters for open-shell states.

  20. Characterization of the Mobility and Reactivity of Water Molecules on TiO2 Nanoparticles by 1H Solid-State Nuclear Magnetic Resonance

    NASA Astrophysics Data System (ADS)

    Wang, Xiaoliang; Zhu, Lili; Sun, Pingchuan; Zhou, Dongshan; Xue, Gi

    2015-03-01

    Understanding interfacial water behavior is essential to improving our understanding of the surface chemistry and interfacial properties of nanomaterials. Here using 1H solid-state nuclear magnetic resonance (1H SSNMR), we successfully monitored ligand exchange reaction between oleylamine (OLA) and adsorbed water on titanium dioxide nanoparticles (TiO2 NPs). Three different types of interfacial waters with different reactivities were distinguished. The mobility of the adsorbed water molecules was characterized by dipolar filtered 1H SSNMR. Our experimental results demonstrate that the adsorbed water can be categorized into three different layers: rigid water species with restricted mobility closest to the surface of TiO2 NPs; less mobile water species weakly confined on TiO2 NPs; and water molecules with high mobility. Water in the third layer could be replaced by OLA, while water in the first and second layers remained intact. The finding that the interfacial water with the highest mobility has the strongest reactivity has guiding significance for tailoring the hydrophilic and hydrophobic properties of TiO2 NPs. We gratefully acknowledge support from the National Natural Science Foundation of China (No. 21174062).

  1. Intercellular adhesion molecule 1 is a sensitive and diagnostically useful immunohistochemical marker of papillary thyroid cancer (PTC) and of PTC-like nuclear alterations in Hashimoto's thyroiditis

    PubMed Central

    ZHANG, KE; GE, SHU-JIAN; LIN, XIAO-YAN; LV, BEI-BEI; CAO, ZHI-XIN; LI, JIA-MEI; XU, JIA-WEN; WANG, QIANG-XIU

    2016-01-01

    Intercellular adhesion molecule 1 (ICAM-1) is important in the progression of inflammatory responses. Recently, increased levels of ICAM-1 have been reported in a number of types of malignancy. The present study aimed to investigate ICAM-1 expression in papillary thyroid cancer (PTC) and in Hashimoto's thyroiditis (HT) with PTC-like nuclear alterations, and to assess the predictive value of ICAM-1 in thyroid lesions. ICAM-1 expression was retrospectively investigated in 132 consecutive cases of PTC, 72 cases of HT, 10 of follicular cancer, 15 of follicular adenoma, 16 of nodular goiter and 8 samples of normal thyroid tissue using immunohistochemical analyses, and in 42 PTC patients using western blotting. ICAM-1 expression was not detected in normal follicular cells, follicular lesions (adenoma and cancer) and benign nodular hyperplasia, but was frequently overexpressed in PTC cells. ICAM-1 overexpression was associated with extra-thyroidal invasion and lymph node metastasis; no association was found with age, gender, tumor size, multifocality, pathological stage, recurrence or distant metastasis. ICAM-1 expression in HT patients with PTC-like nuclear alterations was significantly higher than that in HT cases with non-PTC-like features. Compared with antibodies against cytokeratin 19, galectin-3 and Hector Battifora mesothelial-1, ICAM-1 was the most sensitive marker for the detection of PTC-like features in HT. These findings demonstrate that ICAM-1 expression is upregulated in PTC and in HT with PTC-like nuclear alterations. This feature may be an important factor in the progression of cancer of the thyroid gland. PMID:26998068

  2. Path-Integral Calculations of Nuclear Quantum Effects in Model Systems, Small Molecules, and Enzymes via Gradient-Based Forward Corrector Algorithms.

    PubMed

    Azuri, Asaf; Engel, Hamutal; Doron, Dvir; Major, Dan Thomas

    2011-05-10

    A practical approach to treat nuclear quantum mechanical (QM) effects in simulations of condensed phases, such as enzymes, is via Feynman path integral (PI) formulations. Typically, the standard primitive approximation (PA) is employed in enzymatic PI simulations. Nonetheless, these PI simulations are computationally demanding due to the large number of discretizations, or beads, required to obtain converged results. The efficiency of PI simulations may be greatly improved if higher order factorizations of the density matrix operator are employed. Herein, we compare the results of model calculations obtained employing the standard PA, the improved operator of Takahashi and Imada (TI), and several gradient-based forward corrector algorithms due to Chin (CH). The quantum partition function is computed for the harmonic oscillator, Morse, symmetric, and asymmetric double well potentials. These potentials are simple models for nuclear quantum effects, such as zero-point energy and tunneling. It is shown that a unique set of CH parameters may be employed for a variety of systems. Additionally, the nuclear QM effects of a water molecule, treated with density functional theory, are computed. Finally, we derive a practical perturbation expression for efficient computation of isotope effects in chemical systems using the staging algorithm. This new isotope effect approach is tested in conjunction with the PA, TI, and CH methods to compute the equilibrium isotope effect in the Schiff base-oxyanion keto-enol tautomerism in the cofactor pyridoxal-5'-phosphate in the enzyme alanine racemase. The study of the different factorization methods reveals that the higher-order actions converge substantially faster than the PA approach, at a moderate computational cost.

  3. Interactions of Histone Acetyltransferase p300 with the Nuclear Proteins Histone and HMGB1, As Revealed by Single Molecule Atomic Force Spectroscopy.

    PubMed

    Banerjee, S; Rakshit, T; Sett, S; Mukhopadhyay, R

    2015-10-22

    One of the important properties of the transcriptional coactivator p300 is histone acetyltransferase (HAT) activity that enables p300 to influence chromatin action via histone modulation. p300 can exert its HAT action upon the other nuclear proteins too--one notable example being the transcription-factor-like protein HMGB1, which functions also as a cytokine, and whose accumulation in the cytoplasm, as a response to tissue damage, is triggered by its acetylation. Hitherto, no information on the structure and stability of the complexes between full-length p300 (p300FL) (300 kDa) and the histone/HMGB1 proteins are available, probably due to the presence of unstructured regions within p300FL that makes it difficult to be crystallized. Herein, we have adopted the high-resolution atomic force microscopy (AFM) approach, which allows molecularly resolved three-dimensional contour mapping of a protein molecule of any size and structure. From the off-rate and activation barrier values, obtained using single molecule dynamic force spectroscopy, the biochemical proposition of preferential binding of p300FL to histone H3, compared to the octameric histone, can be validated. Importantly, from the energy landscape of the dissociation events, a model for the p300-histone and the p300-HMGB1 dynamic complexes that HAT forms, can be proposed. The lower unbinding forces of the complexes observed in acetylating conditions, compared to those observed in non-acetylating conditions, indicate that upon acetylation, p300 tends to weakly associate, probably as an outcome of charge alterations on the histone/HMGB1 surface and/or acetylation-induced conformational changes. To our knowledge, for the first time, a single molecule level treatment of the interactions of HAT, where the full-length protein is considered, is being reported.

  4. Espin actin-cytoskeletal proteins are in rat type I spiral ganglion neurons and include splice-isoforms with a functional nuclear localization signal.

    PubMed

    Sekerková, Gabriella; Zheng, Lili; Mugnaini, Enrico; Bartles, James R

    2008-08-20

    The espins are Ca(2+)-resistant actin-bundling proteins that are enriched in hair cell stereocilia and sensory cell microvilli. Here, we report a novel localization of espins to a large proportion of rat type I spiral ganglion neurons (SGNs) and their projections to the cochlear nucleus (CN). Moreover, we show that a fraction of these espins is in the nucleus of SGNs owing to the presence of splice-isoforms that contain a functional nuclear localization signal (NLS). Espin antibody labeled approximately 83% of type I SGNs, and the labeling intensity increased dramatically during early postnatal development. Type II SGNs and vestibular ganglion neurons were unlabeled. In the CN, espin-positive auditory nerve fibers showed a projection pattern typical of type I SGNs, with intense labeling in the nerve root region and posteroventral CN (PVCN). The anteroventral CN (AVCN) showed moderate labeling, whereas the dorsal CN showed weak labeling that was restricted to the deep layer. Espin-positive synaptic terminals were enriched around nerve root neurons and octopus cells in the PVCN and were also found on globular bushy cells and multipolar neurons in the PVCN and AVCN. SGNs expressed multiple espin transcripts and proteins, including splice-isoforms that contain a nonapeptide, which is rich in positively charged amino acids and creates a bipartite NLS. The nonapeptide was necessary to target espin isoforms to the nucleus and was sufficient to target an unrelated protein to the nucleus when joined with the upstream di-arginine-containing octapeptide. The presence of cytoplasmic and nuclear espins in SGNs suggests additional roles for espins in auditory neuroscience.

  5. Loss of Drosophila A-type lamin C initially causes tendon abnormality including disintegration of cytoskeleton and nuclear lamina in muscular defects.

    PubMed

    Uchino, Ryo; Nonaka, Yu-Ki; Horigome, Tuneyoshi; Sugiyama, Shin; Furukawa, Kazuhiro

    2013-01-01

    Lamins are the major components of nuclear envelope architecture, being required for both the structural and informational roles of the nuclei. Mutations of lamins cause a spectrum of diseases in humans, including muscular dystrophy. We report here that the loss of the A-type lamin gene, lamin C in Drosophila resulted in pupal metamorphic lethality caused by tendon defects, matching the characteristics of human A-type lamin revealed by Emery-Dreifuss muscular dystrophy (EDMD). In tendon cells lacking lamin C activity, overall cell morphology was affected and organization of the spectraplakin family cytoskeletal protein Shortstop which is prominently expressed in tendon cells gradually disintegrated, notably around the nucleus and in a manner correlating well with the degradation of musculature. Furthermore, lamin C null mutants were efficiently rescued by restoring lamin C expression to shortstop-expressing cells, which include tendon cells but exclude skeletal muscle cells. Thus the critical function of A-type lamin C proteins in Drosophila musculature is to maintain proper function and morphology of tendon cells.

  6. High nuclearity single-molecule magnets: a mixed-valence Mn26 cluster containing the di-2-pyridylketone diolate dianion.

    PubMed

    Stamatatos, Theocharis C; Nastopoulos, Vassilios; Tasiopoulos, Anastasios J; Moushi, Eleni E; Wernsdorfer, Wolfgang; Christou, George; Perlepes, Spyros P

    2008-11-03

    The employment of the dianion (dpkd(2-)) of the gem-diol form of di-2-pyridylketone (dpk) as a tetradentate chelate in manganese chemistry is reported, and the synthesis, crystal structure, and magnetochemical characterization of [Mn26O16(OMe)12(dpkd)12(MeOH)6](OH)6 x solv (3 x solv) are described. The reaction of Mn(ClO4)2 x 6 H2O, dpk, NaOMe, and NEt3 (2:1:4:2) in MeCN/MeOH affords complex 3, which possesses a rare metal topology and is mixed-valence (4 Mn(II), 22 Mn(III)). The complicated [Mn26(mu4-O)10(mu3-O)6(mu3-OMe)12(mu-OR)12](18+) core of 3 consists of an internal Mn(III)16 cage of adjacent Mn4 tetrahedra surrounded by an external Mn(II)4Mn(III)6 shell. The latter is held together by the alkoxide arms of twelve eta(1):eta(2):eta(1):eta(1):mu3 dpkd(2-) groups. Variable-temperature, solid-state direct current (dc), and alternating current (ac) magnetization studies were carried out on 3 in the 1.8-300 K range. Complex 3 is predominantly antiferromagnetically coupled with a resulting S = 6 ground state, a conclusion confirmed by the in-phase (chi'(M)) ac susceptibility data. The observation of out-of-phase (chi''(M)) ac susceptibility signals suggested that 3 might be a single-molecule magnet, and this was confirmed by single-crystal magnetization vs dc field sweeps that exhibited hysteresis, the diagnostic property of a magnet. Combined ac chi''(M) and magnetization decay vs time data collected below 1.1 K were used to construct an Arrhenius plot; the fit of the thermally activated region above approximately 0.1 K gave U(eff) = 30 K, where U(eff) is the effective relaxation barrier. At lower temperatures, the complex exhibits temperature-independent relaxation, characteristic of ground-state quantum tunneling of magnetization between the lowest-lying M(s) = +/-6 levels. The combined work demonstrates the ligating flexibility of dipyridyl-diolate chelates and their usefulness in the synthesis of polynuclear Mn(x) clusters with interesting magnetic properties

  7. Berberine inhibits tumor necrosis factor-α-induced expression of inflammatory molecules and activation of nuclear factor-κB via the activation of AMPK in vascular endothelial cells.

    PubMed

    Liu, Su-Jian; Yin, Cai-Xia; Ding, Ming-Chao; Wang, Yi-Zhong; Wang, Hong

    2015-10-01

    Berberine, which is a well‑known drug used in traditional medicine, has been demonstrated to exert diverse pharmacological effects, including anti‑inflammatory effects. However, whether berberine can affect the production of inflammatory molecules in vascular endothelial cells remains to be elucidated. Therefore, the present study aimed to determine the effects of berberine, and the underlying molecular mechanisms of these effects. The effect of berberine on tumor necrosis factor (TNF)‑α‑induced inflammatory molecule expression was examined in cultured human aortic endothelial cells (HAECs). The HAECs were stimulated with TNF‑α and incubated with or without berberine. The activation of nuclear factor (NF)‑κB and adenosine monophosphate‑activated protein kinase (AMPK) were analyzed using western blotting, and the protein secretion of intercellular adhesion molecule (ICAM)‑1 and monocyte chemoattractant protein (MCP)‑1 was measured using ELISA kits. The mRNA expression levels of ICAM‑1 and MCP‑1 were analyzed using reverse transcription‑quantitative polymerase chain reaction. The results of the present study demonstrated that berberine significantly inhibited the TNF‑α‑induced expression of ICAM‑1 and MCP‑1, as well as the activation of NF‑κB in the HAECs. These effects were attenuated following co‑treatment with AMPK inhibitor compound C, or specific small interfering RNAs. In conclusion, the results of the present study indicated that berberine inhibits the TNF‑α‑induced expression of ICAM‑1 and MCP‑1, and the activation of NF‑κB in HAECs in vitro, possibly through the AMPK‑dependent pathway.

  8. Increased expression of CD54, CD18, MHC class II molecules, and proliferating cell nuclear antigen in acute puromycin aminonucleoside nephrosis.

    PubMed

    Fernandez, Lucas; Romero, Maritza; Rincón, Jaimar; Mosquera, Jesús

    2003-01-01

    Cellular infiltration to renal tissues is an important feature during acute puromycin aminonucleoside nephrosis (PAN) in rats. The mechanisms responsible for this infiltration are poorly understood. To elucidate the participation of adhesion molecules in PAN, nephrosis was induced in rats by intraperitoneal puromycin aminonucleoside injection. Controls represent animals injected with a 0.9% saline solution. ICAM-1 (intercellular adhesion molecule 1), CD18 (beta chain of lymphocyte-function-associated antigen), LCA (leukocyte common antigen), ED1 (monocyte/macrophage marker), and proliferating cell nuclear antigen expressions were evaluated in renal tissues 1, 2, and 7 weeks after injection. Frozen sections from PAN rat kidneys showed increased expressions of ICAM-1 and its ligand, and these findings were associated with increased levels of LCA+ and ED1+ cells in glomerulus and interstitium. The kinetics of leukocyte infiltration was similar to the kinetics of ICAM-1 expression: high values at week 2 which returned to normal values at week 7. Increased glomerular and interstitial proliferative activities (proliferating cell nulear antigen positive cells) were also found at week 2 of nephrosis. There was a correlation between ICAM-1 expression and numbers of LCA+ and ED1+ cells and between numbers of LCA+ cells and proliferating cells in glomerulus and interstitium. Correlations between glomerular and tubular ICAM-1 expression, interstitial leukocyte infiltration, and glomerular, interstitial, and tubular proliferative activities with the proteinuria were also observed during the nephrotic phase. In addition, increased lymphocyte binding to PAN renal tissues was observed, and this binding was diminished by anti-LFA-1beta monoclonal antibody pretreatment of lymphocytes. A similar result was found with anti-ICAM-1 monoclonal antibody pretreatment of renal tissues. Our results suggest that increased expression of ICAM-1 and proliferative activity could be important

  9. The effect of an iodine restricted including no sea foods diet, on technetium-99m thyroid scintigraphy: a neglected issue in nuclear medicine practice.

    PubMed

    Javadi, Hamid; Neshandarasli, Isa; Mogharrabi, Mehdi; Jalallat, Sara; Nabipour, Iraj; Assadi, Majid

    2012-01-01

    Although it is recommended to patients to avoid sea food and iodine-containing medications prior to iodine-131 (¹³¹I) scanning, the efficacy of this diet as for technetium-99m pertechnetate ((99m)Tc-P) thyroid scintigraphy is not well addressed in the literature. We evaluated a self-managed, outpatients, iodine restricted diet (IRD) designed to reduce total body iodine in preparation for such a scan. We have studied 39 patients who referred to our Department for multinodular goiter, 30 females and 9 males, aged:14-54 years and their (99m)Tc-P thyroid scintigraphy showed poor visualization of the thyroid gland. These patiens were living in regions with high consumption of sea foods went underwent a two-weeks iodine restriction including restriction of sea food diet for the reduction of iodine body content. These patients were called for a repeated scan after going on a IRD for at least two weeks. The two scans were compared visually, and by semiquantitative analysis. Semiquantitative analysis was applied in 8 regions of interest (ROI) by using Wilcoxon signed rank test. Thirty-six subjects had better quality scintigraphy images in the post IRD thyroid scan, as was visually assessed by two nuclear medicine physicians. Semiquantitatetively, there was a significant difference in the mean counts of ROI of the right and the left thyroid lobes in favor of the post IRD scans (P<0.05). In conclusion, this study suggests that in patients with multinodular goiter, living in regions with high consumption of sea foods a two-weeks diet for the reduction of iodine body content induces in most of the cases a slightly better diagnostic thyroid (99m)Tc-P scan.

  10. Small Molecule Inhibition of Epstein - Barr Virus Nuclear Antigen-1 DNA Binding Activity Interferes with Replication and Persistence of the Viral Genome

    PubMed Central

    Noh, Ka-Won; Joo, Eun Hye; Zhao, Bo; Kieff, Elliott; Kang, Myung-Soo

    2014-01-01

    The replication and persistence of extra chromosomal Epstein-Barr virus (EBV) episome in latently infected cells are primarily dependent on the binding of EBV-encoded nuclear antigen 1 (EBNA1) to the cognate EBV oriP element. In continuation of the previous study, herein we characterized EBNA1 small molecule inhibitors (H20, H31) and their underlying inhibitory mechanisms. In silico docking analyses predicted that H20 fits into a pocket in the EBNA1 DNA binding domain (DBD). However, H20 did not significantly affect EBNA1 binding to its cognate sequence. A limited structure-relationship study of H20 identified a hydrophobic compound H31, as an EBNA1 inhibitor. An in vitro EBNA1 EMSA and in vivo EGFP-EBNA1 confocal microscopy analysis showed that H31 inhibited EBNA1-dependent oriP sequence-specific DNA binding activity, but not sequence-nonspecific chromosomal association. Consistent with this, H31 repressed the EBNA1-dependent transcription, replication, and persistence of an EBV oriP plasmid. Furthermore, H31 induced progressive loss of EBV episome. In addition, H31 selectively retarded the growth of EBV-infected LCL or Burkitt’s lymphoma cells. These data indicate that H31 inhibition of EBNA1-dependent DNA binding decreases transcription from and persistence of EBV episome in EBV-infected cells. These new compounds might be useful probes for dissecting EBNA1 functions in vitro and in vivo. PMID:24486954

  11. Identification of Small Molecule Proliferating Cell Nuclear Antigen (PCNA) Inhibitor That Disrupts Interactions with PIP-box Proteins and Inhibits DNA Replication*

    PubMed Central

    Punchihewa, Chandanamali; Inoue, Akira; Hishiki, Asami; Fujikawa, Yoshihiro; Connelly, Michele; Evison, Benjamin; Shao, Youming; Heath, Richard; Kuraoka, Isao; Rodrigues, Patrick; Hashimoto, Hiroshi; Kawanishi, Masanobu; Sato, Mamoru; Yagi, Takashi; Fujii, Naoaki

    2012-01-01

    We have discovered that 3,3′,5-triiodothyronine (T3) inhibits binding of a PIP-box sequence peptide to proliferating cell nuclear antigen (PCNA) protein by competing for the same binding site, as evidenced by the co-crystal structure of the PCNA-T3 complex at 2.1 Å resolution. Based on this observation, we have designed a novel, non-peptide small molecule PCNA inhibitor, T2 amino alcohol (T2AA), a T3 derivative that lacks thyroid hormone activity. T2AA inhibited interaction of PCNA/PIP-box peptide with an IC50 of ∼1 μm and also PCNA and full-length p21 protein, the tightest PCNA ligand protein known to date. T2AA abolished interaction of PCNA and DNA polymerase δ in cellular chromatin. De novo DNA synthesis was inhibited by T2AA, and the cells were arrested in S-phase. T2AA inhibited growth of cancer cells with induction of early apoptosis. Concurrently, Chk1 and RPA32 in the chromatin are phosphorylated, suggesting that T2AA causes DNA replication stress by stalling DNA replication forks. T2AA significantly inhibited translesion DNA synthesis on a cisplatin-cross-linked template in cells. When cells were treated with a combination of cisplatin and T2AA, a significant increase in phospho(Ser139)histone H2AX induction and cell growth inhibition was observed. PMID:22383522

  12. Stable transfection of Epstein-Barr virus (EBV) nuclear antigen 2 in lymphoma cells containing the EBV P3HR1 genome induces expression of B-cell activation molecules CD21 and CD23.

    PubMed Central

    Cordier, M; Calender, A; Billaud, M; Zimber, U; Rousselet, G; Pavlish, O; Banchereau, J; Tursz, T; Bornkamm, G; Lenoir, G M

    1990-01-01

    A set of B-cell activation molecules, including the Epstein-Barr virus (EBV) receptor CR2 (CD21) and the B-cell activation antigen CD23 (Blast2/Fc epsilon RII), is turned on by infecting EBV-negative B-lymphoma cell lines with immortalizing strains of the viruslike B95-8 (BL/B95 cells). This up regulation may represent one of the mechanisms involved in EBV-mediated B-cell immortalization. The P3HR1 nonimmortalizing strain of the virus, which is deleted for the entire Epstein-Barr nuclear antigen 2 (EBNA2) protein open reading frame, is incapable of inducing the expression of CR2 and CD23, suggesting a crucial role for EBNA2 in the activation of these molecules. In addition, lymphoma cells containing the P3HR1 genome (BL/P3HR1 cells) do not express the viral latent membrane protein (LMP), which is regularly expressed in cells infected with immortalizing viral strains. Using electroporation, we have transfected the EBNA2 gene cloned in an episomal vector into BL/P3HR1 cells and have obtained cell clones that stably express the EBNA2 protein. In these clones, EBNA2 expression was associated with an increased amount of CR2 and CD23 steady-state RNAs. Of the three species of CD23 mRNAs described, the Fc epsilon RIIa species was preferentially expressed in these EBNA2-expressing clones. An increased cell surface expression of CR2 but not of CD23 was observed, and the soluble form of CD23 molecule (SCD23) was released. We were, however, not able to detect any expression of LMP in these cell clones. These data demonstrate that EBNA2 gene is able to complement P3HR1 virus latent functions to induce the activation of CR2 and CD23 expression, and they emphasize the role of EBNA2 protein in the modulation of cellular gene implicated in B-cell proliferation and hence in EBV-mediated B-cell immortalization. Nevertheless, EBNA2 expression in BL/P3HR1 cells is not able to restore the level of CR2 and CD23 expression observed in BL/B95 cells, suggesting that other cellular or viral

  13. Phenolic promiscuity in the cell nucleus--epigallocatechingallate (EGCG) and theaflavin-3,3'-digallate from green and black tea bind to model cell nuclear structures including histone proteins, double stranded DNA and telomeric quadruplex DNA.

    PubMed

    Mikutis, Gediminas; Karaköse, Hande; Jaiswal, Rakesh; LeGresley, Adam; Islam, Tuhidul; Fernandez-Lahore, Marcelo; Kuhnert, Nikolai

    2013-02-01

    Flavanols from tea have been reported to accumulate in the cell nucleus in considerable concentrations. The nature of this phenomenon, which could provide novel approaches in understanding the well-known beneficial health effects of tea phenols, is investigated in this contribution. The interaction between epigallocatechin gallate (EGCG) from green tea and a selection of theaflavins from black tea with selected cell nuclear structures such as model histone proteins, double stranded DNA and quadruplex DNA was investigated using mass spectrometry, Circular Dichroism spectroscopy and fluorescent assays. The selected polyphenols were shown to display affinity to all of the selected cell nuclear structures, thereby demonstrating a degree of unexpected molecular promiscuity. Most interestingly theaflavin-digallate was shown to display the highest affinity to quadruplex DNA reported for any naturally occurring molecule reported so far. This finding has immediate implications in rationalising the chemopreventive effect of the tea beverage against cancer and possibly the role of tea phenolics as "life span essentials".

  14. Nuclear Trafficking in Health and Disease

    PubMed Central

    Mor, Amir; White, Michael A.; Fontoura, Beatriz M.A.

    2014-01-01

    In eukaryotic cells, the cytoplasm and the nucleus are separated by a double-membraned nuclear envelope (NE). Thus, transport of molecules between the nucleus and the cytoplasm occurs via gateways termed the nuclear pore complexes (NPCs), which are the largest intracellular channels in nature. While small molecules can passively translocate through the NPC, large molecules are actively imported into the nucleus by interacting with receptors that bind nuclear pore complex proteins (Nups). Regulatory factors then function in assembly and disassembly of transport complexes. Signaling pathways, cell cycle, pathogens, and other physiopathological conditions regulate various constituents of the nuclear transport machinery. Here, we will discuss several findings related to modulation of nuclear transport during physiological and pathological conditions, including tumorigenesis, viral infection, and congenital syndrome. We will also explore chemical biological approaches that are being used as probes to reveal new mechanisms that regulate nucleocytoplasmic trafficking and that are serving as starting points for drug development. PMID:24530809

  15. Stimulation of nuclear receptor REV-ERBs regulates tumor necrosis factor-induced expression of proinflammatory molecules in C6 astroglial cells

    SciTech Connect

    Morioka, Norimitsu Tomori, Mizuki; Zhang, Fang Fang; Saeki, Munenori; Hisaoka-Nakashima, Kazue; Nakata, Yoshihiro

    2016-01-08

    Under physiological conditions, astrocytes maintain homeostasis in the CNS. Following inflammation and injury to the CNS, however, activated astrocytes produce neurotoxic molecules such as cytokines and chemokines, amplifying the initial molecular-cellular events evoked by inflammation and injury. Nuclear receptors REV-ERBα and REV-ERBβ (REV-ERBs) are crucial in the regulation of inflammation- and metabolism-related gene transcription. The current study sought to elucidate a role of REV-ERBs in rat C6 astroglial cells on the expression of inflammatory molecules following stimulation with the neuroinflammatory cytokine tumor necrosis factor (TNF). Stimulation of C6 cells with TNF (10 ng/ml) significantly increased the mRNA expression of CCL2, interleukin-6 (IL-6), inducible nitric oxide synthase (iNOS), and matrix metalloprotease (MMP)-9, but not fibroblast growth factor-2 (FGF-2), cyclooxygenase-2 (COX-2) and MMP-2. Treatment with either REV-ERB agonists GSK4112 or SR9009 significantly blocked TNF-induced upregulation of CCL2 mRNA and MMP-9 mRNA, but not IL-6 mRNA and iNOS mRNA expression. Furthermore, treatment with RGFP966, a selective histone deacetylase 3 (HDAC3) inhibitor, potently reversed the inhibitory effects of GSK4112 on TNF-induced expression of MMP-9 mRNA, but not CCL2 mRNA. Expression of Rev-erbs mRNA in C6 astroglial cells, primary cultured rat cortical and spinal astrocytes was confirmed by reverse transcription polymerase chain reaction. Together, the findings demonstrate an anti-inflammatory effect, downregulating of MMP-9 and CCL2 transcription, of astroglial REV-ERBs activation through HDAC3-dependent and HDAC3-independent mechanisms. - Highlights: • Rev-erbα mRNA and Rev-erbβ mRNA are expressed in C6 astroglial cells. • TNF increases the expression of CCL2, IL-6, MMP-9 and iNOS mRNA. • REV-ERB activation inhibits CCL2 mRNA and MMP-9 mRNA expression. • HDAC3 activity is involved in the inhibitory effect of REV-ERB on MMP-9 induction.

  16. Effect of Hyperketonemia (Acetoacetate) on Nuclear Factor-κB and p38 Mitogen-Activated Protein Kinase Activation Mediated Intercellular Adhesion Molecule 1 Upregulation in Endothelial Cells

    PubMed Central

    Rains, Justin L.

    2015-01-01

    Abstract Background: Hyperketonemia is a pathological condition observed in patients with type 1 diabetes and ketosis-prone diabetes (KPD), which results in increased blood levels of acetoacetate (AA) and β-hydroxybutyrate (BHB). Frequent episodes of hyperketonemia are associated with a higher incidence of vascular disease. We examined the hypothesis that hyperketonemia activates the nuclear factor-κB (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways that regulate intercellular adhesion molecule 1 (ICAM-1) expression in endothelial cells. Methods: Human umbilical vein endothelial cells (HUVECs) were cultured with AA (0–8 mM) or BHB (0–10 mM) for 0–24 hr. Western blotting was used to determine NF-κB activation in whole-cell lysates. ICAM-1 expression was measured using flow cytometry. Results: Results show a 2.4-fold increase in NF-κB activation in cells treated with 8 mM AA compared to the control. BHB had little or no effect on NF-κB activation. Pretreatment with a reactive oxygen species (ROS) inhibitor [N-acetyl-l-cysteine (NAC)] reduced NF-κB to near-control levels. The expression of AA-induced ICAM-1 was significantly reduced when cells were pretreated with either NAC or p38 MAPK inhibitor. Conclusions: These results suggest that NF-κB and p38 MAPK mediate upregulation of ICAM-1 expression in endothelial cells exposed to elevated levels of AA, which may contribute to the development of vascular disease in diabetes. PMID:25489974

  17. Differential suppression of the aryl hydrocarbon receptor nuclear translocator-dependent function by an aryl hydrocarbon receptor PAS-A-derived inhibitory molecule.

    PubMed

    Xie, Jinghang; Huang, Xin; Park, Miki S; Pham, Hang M; Chan, William K

    2014-03-15

    The aryl hydrocarbon receptor (AhR) heterodimerizes with the aryl hydrocarbon receptor nuclear translocator (Arnt) for transcriptional regulation. We generated three N-terminal deletion constructs of the human AhR of 12-24 kDa in size--namely D1, D2, and D3--to suppress the Arnt function. We observed that all three deletions interact with the human Arnt with similar affinities. D2, which contains part of the AhR PAS-A domain and interacts with the PAS-A domain of Arnt, inhibits the formation of the AhR gel shift complex. D2 suppresses the 3-methylcholanthrene-induced, dioxin response element (DRE)-driven luciferase activity in Hep3B cells and exogenous Arnt reverses this D2 suppression. D2 suppresses the induction of CYP1A1 at both the message and protein levels in Hep3B cells; however, the CYP1B1 induction is not affected. D2 suppresses the recruitment of Arnt to the cyp1a1 promoter but not to the cyp1b1 promoter, partly because the AhR/Arnt heterodimer binds better to the cyp1b1 DRE than to the cyp1a1 DRE. Interestingly, D2 has no effect on the cobalt chloride-induced, hypoxia inducible factor-1 (HIF-1)-dependent expression of vegf, aldolase c, and ldh-a messages. Our data reveal that the flanking sequences of the DRE contribute to the binding affinity of the AhR/Arnt heterodimer to its endogenous enhancers and the function of AhR and HIF-1 can be differentially suppressed by the D2 inhibitory molecule. Copyright © 2014 Elsevier Inc. All rights reserved.

  18. Role of nuclear factor-kappa B in the regulation of intercellular adhesion molecule 1 after infection of human bronchial epithelial cells by Bordetella pertussis.

    PubMed

    Ishibashi, Yoshio; Nishikawa, Akemi

    2003-10-01

    Previous work has demonstrated that infection of human bronchial epithelial cells by Bordetella pertussis up-regulates intercellular adhesion molecule-1 (ICAM-1) gene and protein expression. It has also been shown that interaction of the Arg-Gly-Asp (RGD) site of filamentous hemagglutinin (FHA) with host cell very late antigen (VLA)-5 (alpha 5 beta 1 integrin) is required for the up-regulation of epithelial ICAM-1 expression, and that pertussis toxin (PT) impairs this response. We therefore examined the molecular mechanisms leading to B. pertussis-induced ICAM-1 up-regulation in BEAS-2B human bronchial epithelial cells. A colorimetric nuclear factor kappa B (NF-kappa B) activation assay demonstrated that NF-kappa B was activated in response to infection of these cells with B. pertussis. This activation occurred in an FHA(RGD)-dependent manner, and was blocked by an antibody against VLA-5, implying that binding of the RGD to VLA-5 integrin is involved in NF-kappa B activation. Western blot analysis revealed that the activation of NF-kappa B by B. pertussis was preceded by degradation of I kappa B alpha, a major cytoplasmic inhibitor of NF-kappa B. Pretreatment of the BEAS-2B cells with the NF-kappa B inhibitors pyrrolidine dithiocarbamate (PDTC), MG-132, and SN50 resulted in a marked decrease in B. pertussis-induced ICAM-1 expression, implying the involvement of NF-kappa B in ICAM-1 expression. Purified PT abrogated both NF-kappa B activation and I kappa B alpha degradation. These results suggest that ligation of VLA-5 integrin by FHA induces RGD-dependent NF-kappa B activation, thus leading to the up-regulation of epithelial ICAM-1 expression, and that a PT-sensitive G protein may be involved in this signaling pathway.

  19. Target-specific cytotoxic effects on HER2-expressing cells by the tripartite fusion toxin ZHER2:2891-ABD-PE38X8, including a targeting affibody molecule and a half-life extension domain.

    PubMed

    Liu, Hao; Seijsing, Johan; Frejd, Fredrik Y; Tolmachev, Vladimir; Gräslund, Torbjörn

    2015-08-01

    Development of cancer treatment regimens including immunotoxins is partly hampered by their immunogenicity. Recently, deimmunized versions of toxins have been described, potentially being better suited for translation to the clinic. In this study, a recombinant tripartite fusion toxin consisting of a deimmunized version of exotoxin A from Pseudomonas aeruginosa (PE38) genetically fused to an affibody molecule specifically interacting with the human epidermal growth factor receptor 2 (HER2), and also an albumin binding domain (ABD) for half-life extension, has been produced and characterized in terms of functionality of the three moieties. Biosensor based assays showed that the fusion toxin was able to interact with human and mouse serum albumin, but not with bovine serum albumin and that it interacted with HER2 (KD=5 nM). Interestingly, a complex of the fusion toxin and human serum albumin also interacted with HER2 but with a somewhat weaker affinity (KD=12 nM). The IC50-values of the fusion toxin ranged from 6 to 300 pM on SKOV-3, SKBR-3 and A549 cells and was lower for cells with higher surface densities of HER2. The fusion toxin was found specific for HER2 as shown by blocking available HER2 receptors with free affibody molecule before subjecting the cells to the toxin. Analysis of contact time showed that 10 min was sufficient to kill 50% of the cells. In conclusion, all three regions of the fusion toxin were found to be functional.

  20. Quantum ring-polymer contraction method: Including nuclear quantum effects at no additional computational cost in comparison to ab initio molecular dynamics

    NASA Astrophysics Data System (ADS)

    John, Christopher; Spura, Thomas; Habershon, Scott; Kühne, Thomas D.

    2016-04-01

    We present a simple and accurate computational method which facilitates ab initio path-integral molecular dynamics simulations, where the quantum-mechanical nature of the nuclei is explicitly taken into account, at essentially no additional computational cost in comparison to the corresponding calculation using classical nuclei. The predictive power of the proposed quantum ring-polymer contraction method is demonstrated by computing various static and dynamic properties of liquid water at ambient conditions using density functional theory. This development will enable routine inclusion of nuclear quantum effects in ab initio molecular dynamics simulations of condensed-phase systems.

  1. FBI-1 can stimulate HIV-1 Tat activity and is targeted to a novel subnuclear domain that includes the Tat-P-TEFb-containing nuclear speckles.

    PubMed

    Pendergrast, P Shannon; Wang, Chen; Hernandez, Nouria; Huang, Sui

    2002-03-01

    FBI-1 is a cellular POZ-domain-containing protein that binds to the HIV-1 LTR and associates with the HIV-1 transactivator protein Tat. Here we show that elevated levels of FBI-1 specifically stimulate Tat activity and that this effect is dependent on the same domain of FBI-1 that mediates Tat-FBI-1 association in vivo. FBI-1 also partially colocalizes with Tat and Tat's cellular cofactor, P-TEFb (Cdk9 and cyclin T1), at the splicing-factor-rich nuclear speckle domain. Further, a less-soluble population of FBI-1 distributes in a novel peripheral-speckle pattern of localization as well as in other nuclear regions. This distribution pattern is dependent on the FBI-1 DNA binding domain, on the presence of cellular DNA, and on active transcription. Taken together, these results suggest that FBI-1 is a cellular factor that preferentially associates with active chromatin and that can specifically stimulate Tat-activated HIV-1 transcription.

  2. Nuclear Scans

    MedlinePlus

    Nuclear scans use radioactive substances to see structures and functions inside your body. They use a special ... images. Most scans take 20 to 45 minutes. Nuclear scans can help doctors diagnose many conditions, including ...

  3. Correlation between Asian Dust and Specific Radioactivities of Fission Products Included in Airborne Samples in Tokushima, Shikoku Island, Japan, Due to the Fukushima Nuclear Accident

    SciTech Connect

    Sakama, M.; Nagano, Y.; Kitade, T.; Shikino, O.; Nakayama, S.

    2014-06-15

    Radioactive fission product {sup 131}I released from the Fukushima Daiichi Nuclear Power Plants (FD-NPP) was first detected on March 23, 2011 in an airborne aerosol sample collected at Tokushima, Shikoku Island, located in western Japan. Two other radioactive fission products, {sup 134}Cs and {sup 137}Cs were also observed in a sample collected from April 2 to 4, 2011. The maximum specific radioactivities observed in this work were about 2.5 to 3.5 mBq×m{sup -3} in a airborne aerosol sample collected on April 6. During the course of the continuous monitoring, we also made our first observation of seasonal Asian Dust and those fission products associated with the FDNPP accident concurrently from May 2 to 5, 2011. We found that the specific radioactivities of {sup 134}Cs and {sup 137}Cs decreased drastically only during the period of Asian Dust. And also, it was found that this trend was very similar to the atmospheric elemental concentration (ng×m{sup -3}) variation of stable cesium ({sup 133}Cs) quantified by elemental analyses using our developed ICP-DRC-MS instrument.

  4. Linear-scaling method for calculating nuclear magnetic resonance chemical shifts using gauge-including atomic orbitals within Hartree-Fock and density-functional theory.

    PubMed

    Kussmann, Jörg; Ochsenfeld, Christian

    2007-08-07

    Details of a new density matrix-based formulation for calculating nuclear magnetic resonance chemical shifts at both Hartree-Fock and density functional theory levels are presented. For systems with a nonvanishing highest occupied molecular orbital-lowest unoccupied molecular orbital gap, the method allows us to reduce the asymptotic scaling order of the computational effort from cubic to linear, so that molecular systems with 1000 and more atoms can be tackled with today's computers. The key feature is a reformulation of the coupled-perturbed self-consistent field (CPSCF) theory in terms of the one-particle density matrix (D-CPSCF), which avoids entirely the use of canonical MOs. By means of a direct solution for the required perturbed density matrices and the adaptation of linear-scaling integral contraction schemes, the overall scaling of the computational effort is reduced to linear. A particular focus of our formulation is to ensure numerical stability when sparse-algebra routines are used to obtain an overall linear-scaling behavior.

  5. Diet-dependent retinoid effects on liver gene expression include stellate and inflammation markers and parallel effects of the nuclear repressor Shp.

    PubMed

    Maguire, Meghan; Bushkofsky, Justin R; Larsen, Michele Campaigne; Foong, Yee Hoon; Tanumihardjo, Sherry A; Jefcoate, Colin R

    2017-09-01

    For mice, a maternal vitamin A (VA)-deficient diet initiated from midgestation (GVAD) produces serum retinol deficiency in mature offspring. We hypothesize that the effects of GVAD arise from preweaning developmental changes. We compare the effect of this GVAD protocol in combination with a postweaning high-fat diet (HFD) or high-carbohydrate diet (LF12). Each is compared to an equivalent VA-sufficient combination. GVAD extensively decreased serum retinol and liver retinol, retinyl esters, and retinoid homeostasis genes (Lrat, Cyp26b1 and Cyp26a1). These suppressions were each more effective with LF12 than with HFD. Postweaning initiation of VA deficiency with LF12 depleted liver retinoids, but serum retinol was unaffected. Liver retinoid depletion, therefore, precedes serum attenuation. Maternal LF12 decreased the obesity response to the HFD, which was further decreased by GVAD. LF12 fed to the mother and offspring extensively stimulated genes marking stellate activation (Col1a1, Timp2 and Cyp1b1) and novel inflammation markers (Ly6d, Trem2 and Nupr1). The GVAD with LF12 diet combination suppressed these responses. GVAD in combination with the HFD increased these same clusters. A further set of expression differences on the HFD when compared to a high-carbohydrate diet was prevented when GVAD was combined with HFD. Most of these GVAD gene changes match published effects from deletion of Nr0b2/Shp, a retinoid-responsive, nuclear co-repressor that modulates metabolic homeostasis. The stellate and inflammatory increases seen with the high-carbohydrate LF12 diet may represent postprandial responses. They depend on retinol and Shp, but the regulation reverses with an HFD. Copyright © 2017. Published by Elsevier Inc.

  6. Nuclear Fuels.

    ERIC Educational Resources Information Center

    Nash, J. Thomas

    1983-01-01

    Trends in and factors related to the nuclear industry and nuclear fuel production are discussed. Topics addressed include nuclear reactors, survival of the U.S. uranium industry, production costs, budget cuts by the Department of Energy and U.S. Geological survey for resource studies, mining, and research/development activities. (JN)

  7. Nuclear Fuels.

    ERIC Educational Resources Information Center

    Nash, J. Thomas

    1983-01-01

    Trends in and factors related to the nuclear industry and nuclear fuel production are discussed. Topics addressed include nuclear reactors, survival of the U.S. uranium industry, production costs, budget cuts by the Department of Energy and U.S. Geological survey for resource studies, mining, and research/development activities. (JN)

  8. Oscillator strengths for 1s2 1S0-1s2p 3P1,2 transitions in helium-like carbon, nitrogen and oxygen including the effects of a finite nuclear mass

    NASA Astrophysics Data System (ADS)

    Morton, Donald C.; Drake, G. W. F.

    2016-12-01

    We have calculated the electric dipole (E1) and magnetic quadrupole (M2) oscillator strengths and spontaneous decay rates for the 1{{{s}}}2{}1{{{S}}}0{--}1{{s}}2{{p}}{}3{{{P}}}{1,2} spin-changing transitions of helium-like C v, N vi and O vii. We added the effects of the finite nuclear mass and the anomalous magnetic moment of the electron including an extra term derived by Pachucki. For the E1 calculations we used the Breit approximation and pseudostate expansions to perform the perturbation sums over intermediate states in both the length and velocity gauge as a check on numerical accuracy and the validity of the transition operators. There is some cancellation in the corrections for the nuclear mass and the electron anomaly so that if one is included the other should not be ignored

  9. Research in Biological and Medical Sciences Including Biochemistry, Communicable Disease and Immunology, Internal Medicine, Nuclear Medicine, Physiology, Psychiatry, Surgery, and Veterinary Medicine. Volume 2

    DTIC Science & Technology

    1974-06-30

    an enamel pan and much of the debris removed by a series of filtration steps. The glands were then concen- trated by centrlfugation. At present...12600 Phamacoloß- 01PQ00 Physiolopy ■> pan Dm 73 07 CONT H »tA^MIAMCIMTMOB C, In-House I» VtMOHl« AfttMCV DA CONTRACT «AAMT 0...barbiturates on neurotransmitter chemicals in brain and cerebro - spinal fluid. Research methods employed include neurochemistry, neuroanatomy, pharmacology

  10. Research in Biological and Medical Sciences, Including Biochemistry, Communicable Disease and Immunology, Internal Medicine, Nuclear Medicine, Physiology, Psychiatry, Surgery, and Veterinary Medicine. Volume 1

    DTIC Science & Technology

    1975-07-01

    to zero time and Ab, controls run in every experiment included test media, baby bunny complement (c’). Ab + c’ and cells alone. Significance of...been determined that the gonococcl phagocytlzed by baby hamster kidney (BHK) cells remain viable and are protected while intracellular from the...its ill patients to the Ward 7 well- baby nursery. Discussion. The association of certain strains of E. coll with infantile diarrhea was made over

  11. Nuclear magnetic resonance blood flowmeter

    SciTech Connect

    Battocletti, J.H.; Halbach, R.E.; Antonich, F.J.; Sances, A. Jr.; Knox, T.A.

    1986-09-23

    An improved nuclear magnetic resonance blood flowmeter is described for non-invasively measuring blood flow in a human limb comprising; polarizing magnet means for generating a substantially uniform magnetic field; a limb receiving lumen for supporting a human limb within the field generated by the polarizing magnet means so that blood molecules within the limb are magnetically polarized thereby; transmitter means located adjacent the lumen for inducing a nuclear magnetic resonance response in the blood molecules of the human limb disposed within the lumen; scanning means including: first means for generating a first pair of opposing magnetic fields within the lumen for cancelling the nuclear magnetic resonance response induced by the transmitter means everywhere except within a first null plane along which the first opposing magnetic fields cancel each other; second means for generating a second pair of opposing magnetic fields; and control means coupled to the first and second means for generating the first and second pair of opposing magnetic fields.

  12. Raf Kinase Inhibitor Protein (RKIP) Inhibits Tumor Necrosis Factor-α (TNF-α) Induced Adhesion Molecules Expression in Vascular Smooth Muscle Bells by Suppressing (Nuclear Transcription Factor-κB (NF-kappaB) Pathway.

    PubMed

    Jing, Shen-Hong; Gao, Xuan; Yu, Bo; Qiao, Hong

    2017-10-06

    BACKGROUND Raf kinase inhibitor protein (RKIP) regulates growth and differentiation and plays a role in key signal transduction cascades in mammalian cells. Nevertheless, the underlying mechanism for which RKIP regulates cell-cell adhesion remains unknown. Our study investigated the function of the RKIP overexpression on adhesion molecules expression induced by tumor necrosis factor (TNF)-α in cultured mouse vascular smooth muscle cells (MOVACs). MATERIAL AND METHODS The expression levels of vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1) were detected by ELISA kit, reverse transcription-PCR, and western blot assays. The protein expression of RKIP, p65, and inhibitor of nuclear factor (NF)-κBα (IκBα) were detected by western blot analysis. The activity of NF-kappaB was determined using a Dual-Luciferase Reporter assay. RESULTS The results showed that MOVACs transfected with pCMV5-HA-RKIP significantly inhibited TNF-α induced mRNA and protein expression of ICAM-1 and VCAM-1. The adhesion of THP-1 cells was also detected and inhibited by pCMV5-HA-RKIP in TNF-α-treated MOVACs. RKIP also suppressed the TNF-α-induced activation of NF-kappaB and the protein expression of phosphorylated IκB-α, and promoted the protein expression of IkB-α and nuclear translocation of p65 NF-kappaB. Furthermore, RKIP and the inhibitor of NF-kappaB (BAY11-7082) reduced the upregulation of ICAM-1 and VACM-1 induced by TNF-α. CONCLUSIONS Taken together, these results suggested that RKIP may inhibit the TNF-α-induced expression of adhesion molecules in MOVACs through inactivation of the NF-kappaB pathway.

  13. Overview of Non-nuclear Testing of the Safe, Affordable 30-kW Fission Engine, Including End-to-End Demonstrator Testing

    NASA Technical Reports Server (NTRS)

    VanDyke, M. K.; Martin, J. J.; Houts, M. G.

    2003-01-01

    Successful development of space fission systems will require an extensive program of affordable and realistic testing. In addition to tests related to design/development of the fission system, realistic testing of the actual flight unit must also be performed. At the power levels under consideration (3-300 kW electric power), almost all technical issues are thermal or stress related and will not be strongly affected by the radiation environment. These issues can be resolved more thoroughly, less expensively, and in a more timely fashing with nonnuclear testing, provided it is prototypic of the system in question. This approach was used for the safe, affordable fission engine test article development program and accomplished viz cooperative efforts with Department of Energy labs, industry, universiites, and other NASA centers. This Technical Memorandum covers the analysis, testing, and data reduction of a 30-kW simulated reactor as well as an end-to-end demonstrator, including a power conversion system and an electric propulsion engine, the first of its kind in the United States.

  14. Efficiency gains in tracer identification for nuclear imaging: can in vivo LC-MS/MS evaluation of small molecules screen for successful PET tracers?

    PubMed

    Joshi, Elizabeth M; Need, Anne; Schaus, John; Chen, Zhaogen; Benesh, Dana; Mitch, Charles; Morton, Stuart; Raub, Thomas J; Phebus, Lee; Barth, Vanessa

    2014-12-17

    Positron emission tomography (PET) imaging has become a useful noninvasive technique to explore molecular biology within living systems; however, the utility of this method is limited by the availability of suitable radiotracers to probe specific targets and disease biology. Methods to identify potential areas of improvement in the ability to predict small molecule performance as tracers prior to radiolabeling would speed the discovery of novel tracers. In this retrospective analysis, we characterized the brain penetration or peak SUV (standardized uptake value), binding potential (BP), and brain exposure kinetics across a series of known, nonradiolabeled PET ligands using in vivo LC-MS/MS (liquid chromatography coupled to mass spectrometry) and correlated these parameters with the reported PET ligand performance in nonhuman primates and humans available in the literature. The PET tracers studied included those reported to label G protein-coupled receptors (GPCRs), intracellular enzymes, and transporters. Additionally, data for each tracer was obtained from a mouse brain uptake assay (MBUA), previously published, where blood-brain barrier (BBB) penetration and clearance parameters were assessed and compared against similar data collected on a broad compound set of central nervous system (CNS) therapeutic compounds. The BP and SUV identified via nonradiolabeled LC-MS/MS, while different from the published values observed in the literature PET tracer data, allowed for an identification of initial criteria values we sought to facilitate increased potential for success from our early discovery screening paradigm. Our analysis showed that successful, as well as novel, clinical PET tracers exhibited BP of greater than 1.5 and peak SUVs greater than approximately 150% at 5 min post dose in rodents. The brain kinetics appeared similar between both techniques despite differences in tracer dose, suggesting linearity across these dose ranges. The assessment of tracers in a

  15. Source of polarized hydrogen molecules

    NASA Astrophysics Data System (ADS)

    Toporkov, D. K.; Gramolin, A. V.; Nikolenko, D. M.; Rachek, I. A.; Sadykov, R. Sh.; Shestakov, Yu. V.; Yurchenko, A. V.; Zevakov, S. A.

    2017-10-01

    A novel source of polarized hydrogen and deuterium molecules has been tested. The use of sextupole superconducting magnets allows us to select molecules with the nuclear spin projection -1 for hydrogen and -2 for deuterium. The measured beam intensity of polarized hydrogen molecules for the nozzle temperature range of 6.5-30 K and a gas flow rate up to 5 ṡ 10-2 Torr ṡ l / s is presented. The measured flux of polarized hydrogen molecules of ≈ 3 ṡ 1012 mol / s is in reasonable agreement with estimations. The obtained results can be used as a basis for the development of a high-intensity source of polarized molecules.

  16. Nuclear Quadrupole Coupling Tensors of 2H in the a-Alum RbAl(SO4)2 · 12D2O and the Dynamical Behaviour of the D2O Molecules. An Investigation by NMR and IR

    NASA Astrophysics Data System (ADS)

    Ramakrishna, J.; Weiden, Norbert; Weiss, Alarich

    1990-04-01

    By single crystal NMR the nuclear quadrupole coupling constants eQΦzz h-1 (2H), the asymmetry parameters η(2H) and the direction cosines of the principal axes of the electric field gradient tensors of the 2H atoms of the two kinds of D2O molecules have been determined at 295 K in RbAl(SO4)2 · 12D2O. The results show that the D2O molecules surrounding the ion Al3+ are "static" within the time scale of the 2H nuclear quadrupole interaction while the D2O belonging to the octahedron around the Rb+ undergoes fast reorientations around the twofold molecular axis. For the two kinds of D2O in the alum we found: eQΦzz(1)h-1 (2H) = 186.5 kHz, η(1),(2H) = 0.1234; eQΦzz(2)h-1 (2H) = 169.7 kHz,η (2)(2H) = 0.1297; eQΦzz(3)h-1(2H) = 122.1 kHz, (2H) = 0.8087. eQΦzz(1) and eQΦzz(2) belong to the "static" D2O molecules and an assignment to the two different 2H atoms has been performed. The IR spectra of RbAl(SO4)2 · 12(H1-xDx)2O have been investigated, and for the O - D stretching frequencies values of 2145 cm-1 , 2235 cm-1 , 2470 cm-1 and 2525 cm -1 have been obtained. They agree well with the relations between ṽOD and eQΦzz h-1(2H) given in the literature.

  17. C-reactive protein activates the nuclear factor-kappaB pathway and induces vascular cell adhesion molecule-1 expression through CD32 in human umbilical vein endothelial cells and aortic endothelial cells.

    PubMed

    Liang, Yao-Jen; Shyu, Kou-Gi; Wang, Bao-Wei; Lai, Ling-Ping

    2006-03-01

    C-reactive protein (CRP) contributes to the process of atherosclerosis by inducing pro-inflammatory changes in endothelial cells. However, the exact receptor involved in CRP-induced endothelial changes remains unclear. Human umbilical vein endothelial cells (HUVECs) and human aortic endothelial cells (HAECs) were used for the experiments. After incubation with CRP, immunoblotting showed a significant decrease of IkappaB protein and electrophoretic mobility shift assay showed a significant increase of nuclear NF-kappaB binding capacity. These changes were associated with a significant increase of vascular cell adhesion molecule-1 (VCAM-1) expression. The mRNA level of CD32, the major binding protein for CRP in endothelial cells, increased significantly as measured by Northern blot and Western blot. When these cells were transfected with siRNA directed against CD32, the mRNA of CD32 decreased significantly. The IkappaB degradation, NF-kappaB nuclear translocation and VCAM-1 up-regulation induced by CRP were all inhibited by treatment with siRNA against CD32. SB203580, a P38 inhibitor, significantly attenuated the CRP-induced responses while SP600125 (c-jun kinase inhibitor) did not. In conclusion, CRP-induced IkappaB degradation, NF-kappaB nuclear translocation and VCAM-1 protein expression in HUVECs and HAECs. CRP also increased the expression of CD32, which might serve as the receptor for CRP in endothelial cells and mediated the effects of CRP.

  18. Connection between energy relations of solids and molecules

    NASA Technical Reports Server (NTRS)

    Smith, John R.; Schlosser, Herbert; Leaf, William; Ferrante, John; Rose, James H.

    1989-01-01

    The universal energy relation, discovered for metallic and covalent solids as well as nuclear matter, is tested for diatomic molecules. It is found that it applies well to covalent diatomic bonds, but that ionic diatomic bonds are in a distinct class. A simple extension of the universal binding energy relation that includes the effects of ionicity ensues. It yields accurate prediction of spectroscopic data for both ionic and covalent bonds in 150 molecules. The form of the covalent part is given by the universal relation, suggesting an intimate relationship between the energetics of solids and diatomic molecules.

  19. Connection between energy relations of solids and molecules

    NASA Technical Reports Server (NTRS)

    Smith, John R.; Schlosser, Herbert; Leaf, William; Ferrante, John; Rose, James H.

    1989-01-01

    The universal energy relation, discovered for metallic and covalent solids as well as nuclear matter, is tested for diatomic molecules. It is found that it applies well to covalent diatomic bonds, but that ionic diatomic bonds are in a distinct class. A simple extension of the universal binding energy relation that includes the effects of ionicity ensues. It yields accurate prediction of spectroscopic data for both ionic and covalent bonds in 150 molecules. The form of the covalent part is given by the universal relation, suggesting an intimate relationship between the energetics of solids and diatomic molecules.

  20. Contributions of tryptophan 24 and glutamate 30 to binding long-lived water molecules in the ternary complex of human dihydrofolate reductase with methotrexate and NADPH studied by site-directed mutagenesis and nuclear magnetic resonance spectroscopy.

    PubMed

    Meiering, E M; Li, H; Delcamp, T J; Freisheim, J H; Wagner, G

    1995-03-24

    Previous NMR studies on the ternary complex of human dihydrofolate reductase (hDHFR) with methotrexate (MTX) and NADPH detected six long-lived bound water molecules. Two of the water molecules, WatA and WatB, stabilize the structure of the protein while the other four, WatC, WatD, WatE and WatF, are involved in substrate binding and specificity. WatE may also act as a proton shuttle during catalysis. Here, the contributions of individual residues to the binding of these water molecules are investigated by performing NMR experiments on ternary complexes of mutant enzymes, W24F, E30A and E30Q. W24 and E30 are conserved residues that form hydrogen bonds with WatE in crystal structures of DHFR. Nuclear Overhauser effects (NOEs) are detected between WatE and the protein in all the mutant complexes, hence WatE still has a long lifetime bound to the complex when one of its hydrogen-bonding partners is deleted or altered by mutagenesis. The NOEs for WatE are much weaker, however, in the mutants than in wild-type. The NOEs for the other water molecules in and near the active site, WatA, WatC, WatD and WatF, also tend to be weaker in the mutant complexes. Little or no change is apparent in the NOEs for WatB, which is located outside the active site, farthest from the mutated residues. The decreased NOE intensities for the bound water molecules could be caused by changes in the positions and/or lifetimes of the water molecules. Chemical shift and NOE data indicate that the mutants have structures very similar to that of wild-type hDHFR, with possible conformational changes occurring only near the mutated residues. Based on the lack of structural change in the protein and evidence for increased structural fluctuations in the active sites of the mutant enzymes, it is likely that the NOE changes are caused, at least in part, by decreases in the lifetimes of the bound water molecules.

  1. Applications of nuclear physics

    DOE PAGES

    Hayes-Sterbenz, Anna Catherine

    2017-01-10

    Today the applications of nuclear physics span a very broad range of topics and fields. This review discusses a number of aspects of these applications, including selected topics and concepts in nuclear reactor physics, nuclear fusion, nuclear non-proliferation, nuclear-geophysics, and nuclear medicine. The review begins with a historic summary of the early years in applied nuclear physics, with an emphasis on the huge developments that took place around the time of World War II, and that underlie the physics involved in designs of nuclear explosions, controlled nuclear energy, and nuclear fusion. The review then moves to focus on modern applicationsmore » of these concepts, including the basic concepts and diagnostics developed for the forensics of nuclear explosions, the nuclear diagnostics at the National Ignition Facility, nuclear reactor safeguards, and the detection of nuclear material production and trafficking. The review also summarizes recent developments in nuclear geophysics and nuclear medicine. The nuclear geophysics areas discussed include geo-chronology, nuclear logging for industry, the Oklo reactor, and geo-neutrinos. The section on nuclear medicine summarizes the critical advances in nuclear imaging, including PET and SPECT imaging, targeted radionuclide therapy, and the nuclear physics of medical isotope production. Lastly, each subfield discussed requires a review article unto itself, which is not the intention of the current review; rather, the current review is intended for readers who wish to get a broad understanding of applied nuclear physics.« less

  2. Applications of nuclear physics.

    PubMed

    Hayes, A C

    2017-02-01

    Today the applications of nuclear physics span a very broad range of topics and fields. This review discusses a number of aspects of these applications, including selected topics and concepts in nuclear reactor physics, nuclear fusion, nuclear non-proliferation, nuclear-geophysics, and nuclear medicine. The review begins with a historic summary of the early years in applied nuclear physics, with an emphasis on the huge developments that took place around the time of World War II, and that underlie the physics involved in designs of nuclear explosions, controlled nuclear energy, and nuclear fusion. The review then moves to focus on modern applications of these concepts, including the basic concepts and diagnostics developed for the forensics of nuclear explosions, the nuclear diagnostics at the National Ignition Facility, nuclear reactor safeguards, and the detection of nuclear material production and trafficking. The review also summarizes recent developments in nuclear geophysics and nuclear medicine. The nuclear geophysics areas discussed include geo-chronology, nuclear logging for industry, the Oklo reactor, and geo-neutrinos. The section on nuclear medicine summarizes the critical advances in nuclear imaging, including PET and SPECT imaging, targeted radionuclide therapy, and the nuclear physics of medical isotope production. Each subfield discussed requires a review article unto itself, which is not the intention of the current review; rather, the current review is intended for readers who wish to get a broad understanding of applied nuclear physics.

  3. Applications of nuclear physics

    NASA Astrophysics Data System (ADS)

    Hayes, A. C.

    2017-02-01

    Today the applications of nuclear physics span a very broad range of topics and fields. This review discusses a number of aspects of these applications, including selected topics and concepts in nuclear reactor physics, nuclear fusion, nuclear non-proliferation, nuclear-geophysics, and nuclear medicine. The review begins with a historic summary of the early years in applied nuclear physics, with an emphasis on the huge developments that took place around the time of World War II, and that underlie the physics involved in designs of nuclear explosions, controlled nuclear energy, and nuclear fusion. The review then moves to focus on modern applications of these concepts, including the basic concepts and diagnostics developed for the forensics of nuclear explosions, the nuclear diagnostics at the National Ignition Facility, nuclear reactor safeguards, and the detection of nuclear material production and trafficking. The review also summarizes recent developments in nuclear geophysics and nuclear medicine. The nuclear geophysics areas discussed include geo-chronology, nuclear logging for industry, the Oklo reactor, and geo-neutrinos. The section on nuclear medicine summarizes the critical advances in nuclear imaging, including PET and SPECT imaging, targeted radionuclide therapy, and the nuclear physics of medical isotope production. Each subfield discussed requires a review article unto itself, which is not the intention of the current review; rather, the current review is intended for readers who wish to get a broad understanding of applied nuclear physics.

  4. Nuclear Safety

    SciTech Connect

    Silver, E G

    1989-01-01

    This document is a review journal that covers significant developments in the field of nuclear safety. Its scope includes the analysis and control of hazards associated with nuclear energy, operations involving fissionable materials, and the products of nuclear fission and their effects on the environment. Primary emphasis is on safety in reactor design, construction, and operation; however, the safety aspects of the entire fuel cycle, including fuel fabrication, spent-fuel processing, nuclear waste disposal, handling of radioisotopes, and environmental effects of these operations, are also treated.

  5. Nuclear astrophysics

    SciTech Connect

    Haxton, W.C.

    1992-01-01

    The problem of core-collapse supernovae is used to illustrate the many connections between nuclear astrophysics and the problems nuclear physicists study in terrestrial laboratories. Efforts to better understand the collapse and mantle ejection are also motivated by a variety of interdisciplinary issues in nuclear, particle, and astrophysics, including galactic chemical evolution, neutrino masses and mixing, and stellar cooling by the emission of new particles. The current status of theory and observations is summarized.

  6. Nuclear astrophysics

    SciTech Connect

    Haxton, W.C.

    1992-12-31

    The problem of core-collapse supernovae is used to illustrate the many connections between nuclear astrophysics and the problems nuclear physicists study in terrestrial laboratories. Efforts to better understand the collapse and mantle ejection are also motivated by a variety of interdisciplinary issues in nuclear, particle, and astrophysics, including galactic chemical evolution, neutrino masses and mixing, and stellar cooling by the emission of new particles. The current status of theory and observations is summarized.

  7. Dissociative electron attachment to the H2O molecule. II. Nuclear dynamics on coupled electronic surfaces within the local complex potential model

    NASA Astrophysics Data System (ADS)

    Haxton, Daniel J.; Rescigno, T. N.; McCurdy, C. W.

    2007-01-01

    We report the results of a first-principles study of dissociative electron attachment to H2O . The cross sections were obtained from nuclear dynamics calculations carried out in full dimensionality within the local complex potential model by using the multiconfiguration time-dependent Hartree method. The calculations employ our previously obtained global, complex-valued, potential-energy surfaces for the three ( B12 , A12 , and B22 ) electronic Feshbach resonances involved in this process. These three metastable states of H2O- undergo several degeneracies, and we incorporate both the Renner-Teller coupling between the B12 and A12 states as well as the conical intersection between the A12 and B22 states into our treatment. The nuclear dynamics are inherently multidimensional and involve branching between different final product arrangements as well as extensive excitation of the diatomic fragment. Our results successfully mirror the qualitative features of the major fragment channels observed, but are less successful in reproducing the available results for some of the minor channels. We comment on the applicability of the local complex potential model to such a complicated resonant system.

  8. Nuclear war: Opposing viewpoints

    SciTech Connect

    Szumski, B.

    1985-01-01

    This book presents opposing viewpoints on nuclear war. Topics discussed include: how nuclear would begin; would humanity survive; would civil defense work; will an arms agreement work; and can space weapons reduce the risk of nuclear war.

  9. Light, Including Ultraviolet

    PubMed Central

    Maverakis, Emanual; Miyamura, Yoshinori; Bowen, Michael P.; Correa, Genevieve; Ono, Yoko; Goodarzi, Heidi

    2009-01-01

    Ultraviolet (UV) light is intricately linked to the functional status of the cutaneous immune system. In susceptible individuals, UV radiation can ignite pathogenic inflammatory pathways leading to allergy or autoimmunity. In others, this same UV radiation can be used as a phototherapy to suppress pathogenic cutaneous immune responses. These vastly different properties are a direct result of UV light’s ability to ionize molecules in the skin and thereby chemically alter them. Sometimes these UV-induced chemical reactions are essential, the formation of pre-vitamin D3 from 7-dehydrocholesterol, for example. In other instances they can be potentially detrimental. UV radiation can ionize a cell’s DNA causing adjacent pyrimidine bases to chemically bond to each other. To prevent malignant transformation, a cell may respond to this UV-induced DNA damage by undergoing apoptosis. Although this pathway prevents skin cancer it also has the potential of inducing or exacerbating autoreactive immune responses by exposing the cell’s nuclear antigens. Ultaviolet-induced chemical reactions can activate the immune system by a variety of other mechanisms as well. In response to UV irradiation keratinocytes secrete cytokines and chemokines, which activate and recruit leukocytes to the skin. In some individuals UV-induced chemical reactions can synthesize novel antigens resulting in a photoallergy. Alternatively, photosensitizing molecules can damage cells by initiating sunburn-like phototoxic reactions. Herein we review all types of UV-induced skin reactions, especially those involving the immune system. PMID:20018479

  10. Light, including ultraviolet.

    PubMed

    Maverakis, Emanual; Miyamura, Yoshinori; Bowen, Michael P; Correa, Genevieve; Ono, Yoko; Goodarzi, Heidi

    2010-05-01

    Ultraviolet (UV) light is intricately linked to the functional status of the cutaneous immune system. In susceptible individuals, UV radiation can ignite pathogenic inflammatory pathways leading to allergy or autoimmunity. In others, this same UV radiation can be used as a phototherapy to suppress pathogenic cutaneous immune responses. These vastly different properties are a direct result of UV light's ability to ionize molecules in the skin and thereby chemically alter them. Sometimes these UV-induced chemical reactions are essential, the formation of pre-vitamin D(3) from 7-dehydrocholesterol, for example. In other instances they can be potentially detrimental. UV radiation can ionize a cell's DNA causing adjacent pyrimidine bases to chemically bond to each other. To prevent malignant transformation, a cell may respond to this UV-induced DNA damage by undergoing apoptosis. Although this pathway prevents skin cancer it also has the potential of inducing or exacerbating autoreactive immune responses by exposing the cell's nuclear antigens. Ultraviolet-induced chemical reactions can activate the immune system by a variety of other mechanisms as well. In response to UV irradiation keratinocytes secrete cytokines and chemokines, which activate and recruit leukocytes to the skin. In some individuals UV-induced chemical reactions can synthesize novel antigens resulting in a photoallergy. Alternatively, photosensitizing molecules can damage cells by initiating sunburn-like phototoxic reactions. Herein we review all types of UV-induced skin reactions, especially those involving the immune system. Published by Elsevier Ltd.

  11. Nuclear Education Update.

    ERIC Educational Resources Information Center

    Winter, Metta L.

    1986-01-01

    Addresses the controversial issue of nuclear education in public schools. Highlights include resolutions passed by the National Congress of Parent Teacher Associations, what nuclear education is, distinction between nuclear education and education in the nuclear age, educational materials, a review of teaching materials, nuclear literacy, and…

  12. Nuclear Education Update.

    ERIC Educational Resources Information Center

    Winter, Metta L.

    1986-01-01

    Addresses the controversial issue of nuclear education in public schools. Highlights include resolutions passed by the National Congress of Parent Teacher Associations, what nuclear education is, distinction between nuclear education and education in the nuclear age, educational materials, a review of teaching materials, nuclear literacy, and…

  13. Nuclear safety

    NASA Technical Reports Server (NTRS)

    Buden, D.

    1991-01-01

    Topics dealing with nuclear safety are addressed which include the following: general safety requirements; safety design requirements; terrestrial safety; SP-100 Flight System key safety requirements; potential mission accidents and hazards; key safety features; ground operations; launch operations; flight operations; disposal; safety concerns; licensing; the nuclear engine for rocket vehicle application (NERVA) design philosophy; the NERVA flight safety program; and the NERVA safety plan.

  14. Enzymatic DNA molecules

    NASA Technical Reports Server (NTRS)

    Joyce, Gerald F. (Inventor); Breaker, Ronald R. (Inventor)

    1998-01-01

    The present invention discloses deoxyribonucleic acid enzymes--catalytic or enzymatic DNA molecules--capable of cleaving nucleic acid sequences or molecules, particularly RNA, in a site-specific manner, as well as compositions including same. Methods of making and using the disclosed enzymes and compositions are also disclosed.

  15. 2-Methyl-pyran-4-one-3-O-β-D-glucopyranoside isolated from leaves of Punica granatum inhibits the TNFα-induced cell adhesion molecules expression by blocking nuclear transcription factor-κB (NF-κB).

    PubMed

    Balwani, Sakshi; Nandi, Debkumar; Jaisankar, Parasuraman; Ghosh, Balaram

    2011-05-01

    Here, we report bioactivity-guided isolation, purification and characterization of a novel compound, 2-methyl-pyran-4-one-3-O-β-d-glucopyranoside (MPG) from the leaves of Punica granatum. The structure of MPG was established on the basis of its detailed spectral analyses. We demonstrated that MPG not only inhibited the expression of cell adhesion molecules but also significantly blocked its functional consequence, that is, the adhesion of neutrophils on human endothelial cells monolayer. To elucidate the molecular mechanism of action of MPG, we showed that MPG decreased the transcript levels of ICAM-1, VCAM-1 and E-selectin genes. Using electrophoretic mobility shift assay (EMSA) and western blot analyses, we demonstrated that MPG significantly blocked both the TNFα-induced translocation and activation of nuclear transcription factor-κB (NF-κB). Thus, MPG could be useful as a novel lead molecule for developing future anti-inflammatory agents. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

  16. Di- and octa-nuclear dysprosium clusters derived from pyridyl-triazole based ligand: {Dy2} showing single molecule magnetic behaviour.

    PubMed

    Akhtar, Muhammad Nadeem; Liao, Xiao-Fen; Chen, Yan-Cong; Liu, Jun-Liang; Tong, Ming-Liang

    2017-02-28

    Two dysprosium aggregates, formulated as [Dy2(μ-OH)2(H2bpte)2Cl2(MeOH)2]Cl2 (1), and [Dy8(μ-OH)8(bpte)8]·24H2O (2) (H2bpte = 1,2-bis(3-(pyridin-2-yl)-1H-1,2,4-triazol-5-yl)ethane), were obtained using solvothermal reactions. Upon changing the metal salt and synthetic reaction conditions, an eight-member {Dy8} (2) ring was isolated. Complex 1 is centrosymmetric in which two {Dy2} clusters are connecting to each other through the hydrogen bonding. Complex 2 forms an eight-member Dy(III) ring with an inner diameter of 4.5 Å and is the first reported {Dy8(μ-OH)8} core in lanthanide-hydroxo clusters. The H2bpte ligand displays trans,trans- and cis,cis-coordination modes in 1 and 2, respectively. Alternating current (ac) magnetic measurements of both complexes were carried out. In 1, the out-of-phase susceptibilities (χ''M) below 9 K confirm the slow relaxation of magnetization, which is a typical characteristic of single-molecule magnets (SMMs).

  17. Solvatochromic shifts of polar and non-polar molecules in ambient and supercritical water: a sequential quantum mechanics/molecular mechanics study including solute-solvent electron exchange-correlation.

    PubMed

    Ma, Haibo; Ma, Yingjin

    2012-12-07

    Polar and non-polar solutes (acetone and benzene) dissolved in ambient water and supercritical water are investigated theoretically using a sequential quantum mechanics (QM)/molecular mechanics (MM) method which combines classical molecular dynamics simulations and QM/MM calculations. From the detailed analysis of the dependence of the QM region size and point charge background region size as well as the different functionals, it is found that the inclusion of the solvent molecules within the first solvation shell into the QM region to account for the exchange-correlation between a solute and neighboring solvent molecules is important for the highly accurate spectral shift calculations, especially vital for the non-polar solutes whose interactions with the solvents are dominated by the quantum dispersions. At the same time, sufficiently large surrounding partial charge region (r(cutoff) ≥15 Å) as well as the functional corrections to describe the long-range dispersion-corrections are also essential for the study of the electronic excited states in condensed phase. Our calculated solvatochromic shift values and their density dependencies at ambient and high temperature conditions are found to be in good agreements with experimental observations. This indicates that sound theoretical studies of solvatochromic shift can be achieved provided that a reasonable computational scheme with sufficiently large N(water) (QM) and r(cutoff) values is implemented. We also find both of aqueous acetone and aqueous benzene under high temperatures present three distinctive regions: low-density gas-like region, supercritical region, and high-density liquid-like region. The plateau behavior of solvatochromic shift in the supercritical region can be ascribed to the solvent clustering around the solute, which is a fundamental phenomenon of supercritical fluids (SCFs). The density dependence of our calculated coordination number of the first solvation shell nicely reproduces the trend

  18. The Orthologue of Sjögren's Syndrome Nuclear Autoantigen 1 (SSNA1) in Trypanosoma brucei Is an Immunogenic Self-Assembling Molecule

    PubMed Central

    Price, Helen P.; Hodgkinson, Michael R.; Curwen, Rachel S.; MacLean, Lorna M.; Brannigan, James A.; Carrington, Mark; Smith, Barbara A.; Ashford, David A.; Stark, Meg; Smith, Deborah F.

    2012-01-01

    Primary Sjögren's Syndrome (PSS) is a highly prevalent autoimmune disease, typically manifesting as lymphocytic infiltration of the exocrine glands leading to chronically impaired lacrimal and salivary secretion. Sjögren's Syndrome nuclear autoantigen 1 (SSNA1 or NA14) is a major specific target for autoantibodies in PSS but the precise function and clinical relevance of this protein are largely unknown. Orthologues of the gene are absent from many of the commonly used model organisms but are present in Chlamyodomonas reinhardtii (in which it has been termed DIP13) and most protozoa. We report the functional characterisation of the orthologue of SSNA1 in the kinetoplastid parasite, Trypanosoma brucei. Both TbDIP13 and human SSNA1 are small coiled-coil proteins which are predicted to be remote homologues of the actin-binding protein tropomyosin. We use comparative proteomic methods to identify potential interacting partners of TbDIP13. We also show evidence that TbDIP13 is able to self-assemble into fibril-like structures both in vitro and in vivo, a property which may contribute to its immunogenicity. Endogenous TbDIP13 partially co-localises with acetylated α-tubulin in the insect procyclic stage of the parasite. However, deletion of the DIP13 gene in cultured bloodstream and procyclic stages of T. brucei has little effect on parasite growth or morphology, indicating either a degree of functional redundancy or a function in an alternative stage of the parasite life cycle. PMID:22363749

  19. Nuclear Disarmament.

    ERIC Educational Resources Information Center

    Johnson, Christopher

    1982-01-01

    Material about nuclear disarmament and the arms race should be included in secondary school curricula. Teachers can present this technical, controversial, and frightening material in a balanced and comprehensible way. Resources for instructional materials are listed. (PP)

  20. Mobius Molecules

    ERIC Educational Resources Information Center

    Eckert, J. M.

    1973-01-01

    Discusses formation of chemical molecules via Mobius strip intermediates, and concludes that many special physics-chemical properties of the fully closed circular form (1) of polyoma DNA are explainable by this topological feature. (CC)

  1. Interstellar Molecules

    ERIC Educational Resources Information Center

    Solomon, Philip M.

    1973-01-01

    Radioastronomy reveals that clouds between the stars, once believed to consist of simple atoms, contain molecules as complex as seven atoms and may be the most massive objects in our Galaxy. (Author/DF)

  2. Modeling Molecules

    NASA Technical Reports Server (NTRS)

    2000-01-01

    The molecule modeling method known as Multibody Order (N) Dynamics, or MBO(N)D, was developed by Moldyn, Inc. at Goddard Space Flight Center through funding provided by the SBIR program. The software can model the dynamics of molecules through technology which stimulates low-frequency molecular motions and properties, such as movements among a molecule's constituent parts. With MBO(N)D, a molecule is substructured into a set of interconnected rigid and flexible bodies. These bodies replace the computation burden of mapping individual atoms. Moldyn's technology cuts computation time while increasing accuracy. The MBO(N)D technology is available as Insight II 97.0 from Molecular Simulations, Inc. Currently the technology is used to account for forces on spacecraft parts and to perform molecular analyses for pharmaceutical purposes. It permits the solution of molecular dynamics problems on a moderate workstation, as opposed to on a supercomputer.

  3. Interstellar Molecules

    ERIC Educational Resources Information Center

    Solomon, Philip M.

    1973-01-01

    Radioastronomy reveals that clouds between the stars, once believed to consist of simple atoms, contain molecules as complex as seven atoms and may be the most massive objects in our Galaxy. (Author/DF)

  4. Mobius Molecules

    ERIC Educational Resources Information Center

    Eckert, J. M.

    1973-01-01

    Discusses formation of chemical molecules via Mobius strip intermediates, and concludes that many special physics-chemical properties of the fully closed circular form (1) of polyoma DNA are explainable by this topological feature. (CC)

  5. Single-Molecule Tracking in Living Cells Using Single Quantum Dot Applications

    PubMed Central

    Baba, Koichi; Nishida, Kohji

    2012-01-01

    Revealing the behavior of single molecules in living cells is very useful for understanding cellular events. Quantum dot probes are particularly promising tools for revealing how biological events occur at the single molecule level both in vitro and in vivo. In this review, we will introduce how single quantum dot applications are used for single molecule tracking. We will discuss how single quantum dot tracking has been used in several examples of complex biological processes, including membrane dynamics, neuronal function, selective transport mechanisms of the nuclear pore complex, and in vivo real-time observation. We also briefly discuss the prospects for single molecule tracking using advanced probes. PMID:22896768

  6. Enumerating molecules.

    SciTech Connect

    Visco, Donald Patrick, Jr.; Faulon, Jean-Loup Michel; Roe, Diana C.

    2004-04-01

    This report is a comprehensive review of the field of molecular enumeration from early isomer counting theories to evolutionary algorithms that design molecules in silico. The core of the review is a detail account on how molecules are counted, enumerated, and sampled. The practical applications of molecular enumeration are also reviewed for chemical information, structure elucidation, molecular design, and combinatorial library design purposes. This review is to appear as a chapter in Reviews in Computational Chemistry volume 21 edited by Kenny B. Lipkowitz.

  7. Direct laser cooling of the BH molecule

    NASA Astrophysics Data System (ADS)

    Holland, Darren; Truppe, Stefan; Hendricks, Richard; Sauer, Ben; Tarbutt, Michael

    2015-03-01

    Ultracold polar molecules are of interest for a variety of applications, including tests of fundamental physics, ultracold chemistry, and simulation of many-body quantum systems. The laser cooling techniques that have been so successful in producing ultracold atoms are difficult to apply to molecules. Recently however, laser cooling has been applied successfully to a few molecular species, and a magneto-optical trap of SrF molecules has now been demonstrated. We have investigated the BH molecule as a candidate for laser cooling. We have produced a molecular beam of BH and have measured the branching ratios for the excited electronic state, A1 Π (v' = 0) , to decay to the various vibrational states of the ground electronic state, X1 Σ . We verify that the branching ratio for the spin-forbidden transition to an intermediate triplet state is inconsequentially small. We measure the frequency of the lowest rotational transition of the X state, and the hyperfine structure in the relevant levels of both the X and A states, and determine the nuclear electric quadrupole and magnetic dipole coupling constants. Our results show that a relatively simple laser cooling scheme can be used to cool, slow and trap BH molecules.

  8. Nuclear analytical chemistry

    SciTech Connect

    Brune, D.; Forkman, B.; Persson, B.

    1984-01-01

    This book covers the general theories and techniques of nuclear chemical analysis, directed at applications in analytical chemistry, nuclear medicine, radiophysics, agriculture, environmental sciences, geological exploration, industrial process control, etc. The main principles of nuclear physics and nuclear detection on which the analysis is based are briefly outlined. An attempt is made to emphasise the fundamentals of activation analysis, detection and activation methods, as well as their applications. The book provides guidance in analytical chemistry, agriculture, environmental and biomedical sciences, etc. The contents include: the nuclear periodic system; nuclear decay; nuclear reactions; nuclear radiation sources; interaction of radiation with matter; principles of radiation detectors; nuclear electronics; statistical methods and spectral analysis; methods of radiation detection; neutron activation analysis; charged particle activation analysis; photon activation analysis; sample preparation and chemical separation; nuclear chemical analysis in biological and medical research; the use of nuclear chemical analysis in the field of criminology; nuclear chemical analysis in environmental sciences, geology and mineral exploration; and radiation protection.

  9. Relativistic Double Group Spinor Representations of Non-rigid Molecules

    SciTech Connect

    Balasubramanian, K

    2003-12-22

    The character theory of relativistic double group spinor representations is developed in order to represent the total rovibronic states of non-rigid molecules. It is shown that the double groups can be represented in terms of wreath products and powerful matrix cycle type generators that are used to construct their character tables. It is shown that these tables are of use when spin-orbit coupling is included in the hamiltonian even for molecules containing lighter atoms. Applications to non-rigid molecules such as Tl{sub 2}H{sub 4} /Tl{sub 2}H{sub 4}{sup +} are considered. It is shown that the tunneling splittings and the nuclear spin statistical weights can be obtained for such species using the character tables thus constructed. The spinor double groups of several other molecules such as hexamethyl dilead and heavy weakly bound clusters such as (PoH{sub 2}){sub 4} are also considered.

  10. Nuclear Speckles

    PubMed Central

    Spector, David L.; Lamond, Angus I.

    2011-01-01

    Nuclear speckles, also known as interchromatin granule clusters, are nuclear domains enriched in pre-mRNA splicing factors, located in the interchromatin regions of the nucleoplasm of mammalian cells. When observed by immunofluorescence microscopy, they usually appear as 20–50 irregularly shaped structures that vary in size. Speckles are dynamic structures, and their constituents can exchange continuously with the nucleoplasm and other nuclear locations, including active transcription sites. Studies on the composition, structure, and dynamics of speckles have provided an important paradigm for understanding the functional organization of the nucleus and the dynamics of the gene expression machinery. PMID:20926517

  11. Genetic Analysis Workshop 15: simulation of a complex genetic model for rheumatoid arthritis in nuclear families including a dense SNP map with linkage disequilibrium between marker loci and trait loci

    PubMed Central

    Miller, Michael B; Lind, Gregg R; Li, Na; Jang, Soon-Young

    2007-01-01

    Data for Problem 3 of the Genetic Analysis Workshop 15 were generated by computer simulation in an attempt to mimic some of the genetic and epidemiological features of rheumatoid arthritis (RA) such as its population prevalence, sex ratio, risk to siblings of affected individuals, association with cigarette smoking, the strong effect of genotype in the HLA region and other genetic effects. A complex genetic model including epistasis and genotype-by-environment interaction was applied to a population of 1.9 million nuclear families of size four from which we selected 1500 families with both offspring affected and 2000 unrelated, unaffected individuals all of whose first-degree relatives were unaffected. This process was repeated to produce 100 replicate data sets. In addition, we generated marker data for 22 autosomes consisting of a genome-wide set of 730 simulated STRP markers, 9187 SNP markers and an additional 17,820 SNP markers on chromosome 6. Appropriate linkage disequilibrium between markers and between trait loci and markers was modelled using HapMap Phase 1 data . The code base for this project was written primarily in the Octave programming language, but it is being ported to the R language and developed into a larger project for general genetic simulation called GenetSim . All of the source code that was used to generate the GAW 15 Problem 3 data is freely available for download at . PMID:18466538

  12. Intelligent distributed control for nuclear power plants. Final (third annual) technical progress report, September 1991--June 1993 (September 1989--June 1993): Includes no-cost extension period from September 1992--June 1993

    SciTech Connect

    Klevans, E.H.

    1993-12-31

    This project was initiated in September 1989 as a three year project to develop and demonstrate Intelligent Distributed Control (IDC) for Nuclear Power Plants. There were two primary goals of this research project. The first goal was to combine diagnostics and control to achieve a highly automated power plant as described by M.A. Schultz. The second goal was to apply this research to develop a prototype demonstration on an actual power plant system, the EBR-2 steam plant. Described in this Final (Third Annual) Technical Progress Report is the accomplishment of the project`s final milestone, an in-plant intelligent control experiment conducted on April 1, 1993. The development of the experiment included: simulation validation, experiment formulation and final programming, procedure development and approval, and experimental results. Other third year developments summarized in this report are: (1) a theoretical foundation for Reconfigurable Hybrid Supervisory Control, (2) a steam plant diagnostic system, (3) control console design tools and (4) other advanced and intelligent control.

  13. Nuclear accidents

    SciTech Connect

    Mobley, J.A.

    1982-05-01

    A nuclear accident with radioactive contamination can happen anywhere in the world. Because expert nuclear emergency teams may take several hours to arrive at the scene, local authorities must have a plan of action for the hours immediately following an accident. The site should be left untouched except to remove casualties. Treatment of victims includes decontamination and meticulous wound debridement. Acute radiation syndrome may be an overwhelming sequela.

  14. The New Nuclear Nations.

    ERIC Educational Resources Information Center

    Spector, Leonard S.

    1990-01-01

    Explores the issue of nuclear proliferation, noting that the countries with nuclear capability now include Israel, South Africa, India, and Pakistan. Describes the role and problems of the United States in halting nuclearization. Supplies charts, maps, and information concerning the state of nuclear capability in each country. (NL)

  15. The New Nuclear Nations.

    ERIC Educational Resources Information Center

    Spector, Leonard S.

    1990-01-01

    Explores the issue of nuclear proliferation, noting that the countries with nuclear capability now include Israel, South Africa, India, and Pakistan. Describes the role and problems of the United States in halting nuclearization. Supplies charts, maps, and information concerning the state of nuclear capability in each country. (NL)

  16. Small GTPase Rho signaling is involved in {beta}1 integrin-mediated up-regulation of intercellular adhesion molecule 1 and receptor activator of nuclear factor {kappa}B ligand on osteoblasts and osteoclast maturation

    SciTech Connect

    Hirai, Fumihiko; Nakayamada, Shingo; Okada, Yosuke; Saito, Kazuyoshi; Kurose, Hitoshi; Mogami, Akira; Tanaka, Yoshiya . E-mail: tanaka@med.uoeh-u.ac.jp

    2007-04-27

    We assessed the characteristics of human osteoblasts, focusing on small GTPase Rho signaling. {beta}1 Integrin were highly expressed on osteoblasts. Engagement of {beta}1 integrins by type I collagen augmented expression of intercellular adhesion molecule 1 (ICAM-1) and receptor activator of nuclear factor {kappa}B ligand (RANKL) on osteoblasts. Rho was activated by {beta}1 stimulation in osteoblasts. {beta}1 Integrin-induced up-regulation of ICAM-1 and RANKL was inhibited by transfection with adenoviruses encoding C3 transferase or pretreated with Y-27632, specific Rho and Rho-kinase inhibitors. Engagement of {beta}1 integrin on osteoblasts induced formation of tartrate-resistant acid phosphatase (TRAP)-positive multinuclear cells (MNC) in a coculture system of osteoblasts and peripheral monocytes, but this action was completely abrogated by transfection of C3 transferase. Our results indicate the direct involvement of Rho-mediated signaling in {beta}1 integrin-induced up-regulation of ICAM-1 and RANKL and RANKL-dependent osteoclast maturation. Thus, Rho-mediated signaling in osteoblasts seems to introduce major biases to bone resorption.

  17. Atoms-in-molecules study of the genetically encoded amino acids. III. Bond and atomic properties and their correlations with experiment including mutation-induced changes in protein stability and genetic coding.

    PubMed

    Matta, Chérif F; Bader, Richard F W

    2003-08-15

    This article presents a study of the molecular charge distributions of the genetically encoded amino acids (AA), one that builds on the previous determination of their equilibrium geometries and the demonstrated transferability of their common geometrical parameters. The properties of the charge distributions are characterized and given quantitative expression in terms of the bond and atomic properties determined within the quantum theory of atoms-in-molecules (QTAIM) that defines atoms and bonds in terms of the observable charge density. The properties so defined are demonstrated to be remarkably transferable, a reflection of the underlying transferability of the charge distributions of the main chain and other groups common to the AA. The use of the atomic properties in obtaining an understanding of the biological functions of the AA, whether free or bound in a polypeptide, is demonstrated by the excellent statistical correlations they yield with experimental physicochemical properties. A property of the AA side chains of particular importance is the charge separation index (CSI), a quantity previously defined as the sum of the magnitudes of the atomic charges and which measures the degree of separation of positive and negative charges in the side chain of interest. The CSI values provide a correlation with the measured free energies of transfer of capped side chain analogues, from the vapor phase to aqueous solution, yielding a linear regression equation with r2 = 0.94. The atomic volume is defined by the van der Waals isodensity surface and it, together with the CSI, which accounts for the electrostriction of the solvent, yield a linear regression (r2 = 0.98) with the measured partial molar volumes of the AAs. The changes in free energies of transfer from octanol to water upon interchanging 153 pairs of AAs and from cyclohexane to water upon interchanging 190 pairs of AAs, were modeled using only three calculated parameters (representing electrostatic and

  18. Strategies on the nuclear-targeted delivery of genes

    PubMed Central

    Yao, Jing; Fan, Ying; Li, Yuanke; Huang, Leaf

    2016-01-01

    To improve the nuclear-targeted delivery of non-viral vectors, extensive effort has been carried out on the development of smart vectors which could overcome multiple barriers. The nuclear envelope presents a major barrier to transgene delivery. Viruses are capable of crossing the nuclear envelope to efficiently deliver their genome into the nucleus through the specialized protein components. However, non-viral vectors are preferred over viral ones because of the safety concerns associated with the latter. Non-viral delivery systems have been designed to include various types of components to enable nuclear translocation at the periphery of the nucleus. This review summarizes the progress of research regarding nuclear transport mechanisms. “Smart” non-viral vectors that have been modified by peptides and other small molecules are able to facilitate the nuclear translocation and enhance the efficacy of gene expression. The resulting technology may also enhance delivery of other macromolecules to the nucleus. PMID:23964565

  19. Nuclear Power in China

    NASA Astrophysics Data System (ADS)

    Zhou, Yun

    2012-02-01

    In response to the Fukushima accident, China is strengthening its nuclear safety at reactors in operation, under construction and in preparation, including efforts to improve nuclear safety regulations and guidelines based on lessons learned from the accident. Although China is one of the major contributors in the global nuclear expansion, China's nuclear power industry is relatively young. Its nuclear safety regulators are less experienced compared to those in other major nuclear power countries. To realize China's resolute commitment to rapid growth of safe nuclear energy, detailed analyses of its nuclear safety regulatory system are required. This talk explains China's nuclear energy program and policy at first. It also explores China's governmental activities and future nuclear development after Fukushima accidents. At last, an overview of China's nuclear safety regulations and practices are provided. Issues and challenges are also identified for police makers, regulators, and industry professionals.

  20. Thermodynamics of nuclear transport

    NASA Astrophysics Data System (ADS)

    Wang, Ching-Hao; Mehta, Pankaj; Elbaum, Michael

    Molecular transport across the nuclear envelope is important for eukaryotes for gene expression and signaling. Experimental studies have revealed that nuclear transport is inherently a nonequilibrium process and actively consumes energy. In this work we present a thermodynamics theory of nuclear transport for a major class of nuclear transporters that are mediated by the small GTPase Ran. We identify the molecular elements responsible for powering nuclear transport, which we term the ``Ran battery'' and find that the efficiency of transport, measured by the cargo nuclear localization ratio, is limited by competition between cargo molecules and RanGTP to bind transport receptors, as well as the amount of NTF2 (i.e. RanGDP carrier) available to circulate the energy flow. This picture complements our current understanding of nuclear transport by providing a comprehensive thermodynamics framework to decipher the underlying biochemical machinery. Pm and CHW were supported by a Simons Investigator in the Mathematical Modeling in Living Systems grant (to PM).

  1. Substituted trans-stilbenes, including analogues of the natural product resveratrol, inhibit the human tumor necrosis factor alpha-induced activation of transcription factor nuclear factor kappaB.

    PubMed

    Heynekamp, Justin J; Weber, Waylon M; Hunsaker, Lucy A; Gonzales, Amanda M; Orlando, Robert A; Deck, Lorraine M; Jagt, David L Vander

    2006-11-30

    The transcription factor nuclear factor kappaB (NF-kappaB), which regulates expression of numerous antiinflammatory genes as well as genes that promote development of the prosurvival, antiapoptotic state is up-regulated in many cancer cells. The natural product resveratrol, a polyphenolic trans-stilbene, has numerous biological activities and is a known inhibitor of activation of NF-kappaB, which may account for some of its biological activities. Resveratrol exhibits activity against a wide variety of cancer cells and has demonstrated activity as a cancer chemopreventive against all stages, i.e., initiation, promotion, and progression. The biological activities of resveratrol are often ascribed to its antioxidant activity. Both antioxidant activity and biological activities of analogues of resveratrol depend upon the number and location of the hydroxy groups. In the present study, phenolic analogues of resveratrol and a series of substituted trans-stilbenes without hydroxy groups were compared with resveratrol for their abilities to inhibit the human tumor necrosis factor alpha-induced (TNF-alpha) activation of NF-kappaB, using the Panomics NF-kappaB stable reporter cell line 293/NF-kappaB-luc. A series of 75 compounds was screened to identify substituted trans-stilbenes that were more active than resveratrol. Dose-response studies of the most active compounds were carried out to obtain IC50 values. Numerous compounds were identified that were more active than resveratrol, including compounds that were devoid of hydroxy groups and were 100-fold more potent than resveratrol. The substituted trans-stilbenes that were potent inhibitors of the activation of NFkappaB generally did not exhibit antioxidant activity. The results from screening were confirmed using BV-2 microglial cells where resveratrol and analogues were shown to inhibit LPS-induced COX-2 expression.

  2. The nuclear freeze controversy

    SciTech Connect

    Payne, K.B.; Gray, C.S.

    1984-01-01

    This book presents papers on nuclear arms control. Topics considered include the background and rationale behind the nuclear freeze proposal, nuclear deterrence, national defense, arms races, arms buildup, warfare, the moral aspects of nuclear deterrence, treaty verification, the federal budget, the economy, a historical perspective on Soviet policy toward the freeze, the other side of the Soviet peace offensive, and making sense of the nuclear freeze debate.

  3. Mechanistic Control of Carcinoembryonic Antigen-related Cell Adhesion Molecule-1 (CEACAM1) Splice Isoforms by the Heterogeneous Nuclear Ribonuclear Proteins hnRNP L, hnRNP A1, and hnRNP M*

    PubMed Central

    Dery, Kenneth J.; Gaur, Shikha; Gencheva, Marieta; Yen, Yun; Shively, John E.; Gaur, Rajesh K.

    2011-01-01

    Carcinoembryonic antigen-related cell adhesion molecule-1 (CEACAM1) is expressed in a variety of cell types and is implicated in carcinogenesis. Alternative splicing of CEACAM1 pre-mRNA generates two cytoplasmic domain splice variants characterized by the inclusion (L-isoform) or exclusion (S-isoform) of exon 7. Here we show that the alternative splicing of CEACAM1 pre-mRNA is regulated by novel cis elements residing in exon 7. We report the presence of three exon regulatory elements that lead to the inclusion or exclusion of exon 7 CEACAM1 mRNA in ZR75 breast cancer cells. Heterologous splicing reporter assays demonstrated that the maintenance of authentic alternative splicing mechanisms were independent of the CEACAM1 intron sequence context. We show that forced expression of these exon regulatory elements could alter CEACAM1 splicing in HEK-293 cells. Using RNA affinity chromatography, three members of the heterogeneous nuclear ribonucleoprotein family (hnRNP L, hnRNP A1, and hnRNP M) were identified. RNA immunoprecipitation of hnRNP L and hnRNP A1 revealed a binding motif located central and 3′ to exon 7, respectively. Depletion of hnRNP A1 or L by RNAi in HEK-293 cells promoted exon 7 inclusion, whereas overexpression led to exclusion of the variable exon. By contrast, overexpression of hnRNP M showed exon 7 inclusion and production of CEACAM1-L mRNA. Finally, stress-induced cytoplasmic accumulation of hnRNP A1 in MDA-MB-468 cells dynamically alters the CEACAM1-S:CEACAM1:L ratio in favor of the l-isoform. Thus, we have elucidated the molecular factors that control the mechanism of splice-site recognition in the alternative splicing regulation of CEACAM1. PMID:21398516

  4. Effects of Nuclear Weapons.

    ERIC Educational Resources Information Center

    Sartori, Leo

    1983-01-01

    Fundamental principles governing nuclear explosions and their effects are discussed, including three components of a nuclear explosion (thermal radiation, shock wave, nuclear radiation). Describes how effects of these components depend on the weapon's yield, its height of burst, and distance of detonation point. Includes effects of three…

  5. Effects of Nuclear Weapons.

    ERIC Educational Resources Information Center

    Sartori, Leo

    1983-01-01

    Fundamental principles governing nuclear explosions and their effects are discussed, including three components of a nuclear explosion (thermal radiation, shock wave, nuclear radiation). Describes how effects of these components depend on the weapon's yield, its height of burst, and distance of detonation point. Includes effects of three…

  6. Molecular targets for small-molecule modulators of circadian clocks

    PubMed Central

    He, Baokun; Chen, Zheng

    2016-01-01

    Background Circadian clocks are endogenous timing systems that regulate various aspects of mammalian metabolism, physiology and behavior. Traditional chronotherapy refers to the administration of drugs in a defined circadian time window to achieve optimal pharmacokinetic and therapeutic efficacies. In recent years, substantial efforts have been dedicated to developing novel small-molecule modulators of circadian clocks. Methods Here, we review the recent progress in the identification of molecular targets of small-molecule clock modulators and their efficacies in clock-related disorders. Specifically, we examine the clock components and regulatory factors as possible molecular targets of small molecules, and we review several key clock-related disorders as promising venues for testing the preventive/therapeutic efficacies of these small molecules. Finally, we also discuss circadian regulation of drug metabolism. Results Small molecules can modulate the period, phase and/or amplitude of the circadian cycle. Core clock proteins, nuclear hormone receptors, and clock-related kinases and other epigenetic regulators are promising molecular targets for small molecules. Through these targets small molecules exert protective effects against clock-related disorders including the metabolic syndrome, immune disorders, sleep disorders and cancer. Small molecules can also modulate circadian drug metabolism and response to existing therapeutics. Conclusion Small-molecule clock modulators target clock components or diverse cellular pathways that functionally impinge upon the clock. Target identification of new small-molecule modulators will deepen our understanding of key regulatory nodes in the circadian network. Studies of clock modulators will facilitate their therapeutic applications, alone or in combination, for clock-related diseases. PMID:26750111

  7. Irving Langmuir Prize in Chemical Physics Lecture: The Inner Machinery of Single Molecules: resolving the unresolved with the STM

    NASA Astrophysics Data System (ADS)

    Ho, Wilson

    2013-03-01

    The scanning tunneling microscope (STM) is a unique instrument that can probe and induce changes in a molecule with atomic scale resolution. Its operation is based on the current that flows between the tip and the substrate with the molecule sandwiched in between. Therefore, the STM can be used to understand the coupling of electrons to the different states and excitations in the molecule and to investigate the influence on them by its environment. From the spatial and energy dependences of the coupling to the charge, spin, and nuclear motions in the molecule, verification of and new insights into the quantum mechanical properties of molecules can be obtained, including the discovery of new conduction and energy transfer mechanisms. This understanding of electron-molecule interactions with the STM enables rational ways to control chemistry and the exploration of novel physical technologies based on molecules.

  8. The Alarmin Properties of DNA and DNA-associated Nuclear Proteins.

    PubMed

    Magna, Melinda; Pisetsky, David S

    2016-05-01

    The communication of cell injury and death is a critical element in host defense. Although immune cells can serve this function by elaborating cytokines and chemokines, somatic cells can repurpose nuclear macromolecules to function as damage-associated molecular patterns (DAMPs) or alarmins to exert similar activity. Among these molecules, DNA, high-mobility group box-1, and histone proteins can all act as DAMPs once they are in an extracellular location. This review describes current information on the role of the nuclear DAMPs, their translocation to the outside of cells, and pathways of activation after uptake into the inside of immune cells. MEDLINE and PubMed databases were searched for citations (1990-2016) in English related to the following terms: DAMPs, high-mobility group box-1, DNA, histones, cell death, danger, and immune activation. Selected articles with the most relevant studies were included for a more detailed consideration. Although nuclear molecules have important structural and genetic regulatory roles inside the cell nucleus, when released into the extracellular space during cell death, these molecules can acquire immune activity and serve as alarmins or DAMPs. Although apoptosis is generally considered the source of extracellular nuclear material, other cell death pathways such as necroptosis, NETosis, and pyroptosis can contribute to the release of nuclear molecules. Importantly, the release of nuclear DAMPs occurs with both soluble and particulate forms of these molecules. The activity of nuclear molecules may depend on posttranslational modifications, redox changes, and the binding of other molecules. Once in an extracellular location, nuclear DAMPs can engage the same pattern recognition receptors as do pathogen-associated molecular patterns. These interactions can activate immune cells and lead to cytokine and chemokine production. Among these receptors, internal receptors for DNA are key to the response to this molecule; the likely

  9. Nuclear pursuits

    SciTech Connect

    Not Available

    1993-05-01

    This table lists quantities of warheads (in stockpile, peak number per year, total number built, number of known test explosions), weapon development milestones (developers of the atomic bomb and hydrogen bomb, date of first operational ICBM, first nuclear-powered naval SSN in service, first MIRVed missile deployed), and testing milestones (first fission test, type of boosted fission weapon, multistage thermonuclear test, number of months from fission bomb to multistage thermonuclear bomb, etc.), and nuclear infrastructure (assembly plants, plutonium production reactors, uranium enrichment plants, etc.). Countries included in the tally are the United States, Soviet Union, Britain, France, and China.

  10. [Nuclear receptors PPAR as a drug target in metabolic disorders].

    PubMed

    Stolarczyk, Marta; Gutman, Wojciech; Derlacz, Rafał A

    2011-01-01

    Nuclear receptors regulate many basic cellular processes and their malfunction can lead to serious consequences including metabolic disorders, obesity and type 2 diabetes. Among many nuclear receptor families, the best known for their therapeutic use are the PPARs. These are key transcription factors determining, proper cellular metabolism of glucose and lipids, tissue sensitivity to insulin, appropriate immune responses including inflammatory processes and finally cell division and differentiation. Currently two types of PPAR activators are in medical use: in the therapy of type 2 diabetes--thiazolidinediones (TZDs), which act via PPARgamma receptors and in the treatment of dyslipidemia-fibrates, which act via PPARalpha receptors. The search for new drugs acting through PPAR mechanism consists in the design of new molecules with tissue specific proprieties, which would selectively bind and modulate the activity of appropriate receptors, thus reducing the number of adverse events typically observed with the use of full agonists. These molecules have been named selective nuclear receptor modulators (SNuRMs).

  11. Differential cross sections for muonic atom scattering from hydrogenic molecules

    SciTech Connect

    Adamczak, Andrzej

    2006-10-15

    The differential cross sections for low-energy muonic hydrogen atom scattering from hydrogenic molecules are directly expressed by the corresponding amplitudes for muonic atom scattering from hydrogen-isotope nuclei. The energy and angular dependence of these three-body amplitudes is thus taken naturally into account in scattering from molecules, without involving any pseudopotentials. Effects of the internal motion of nuclei inside the target molecules are included for every initial rotational-vibrational state. These effects are very significant as the considered three-body amplitudes often vary strongly within the energy interval < or approx. 0.1 eV. The differential cross sections, calculated using the presented method, have been successfully used for planning and interpreting many experiments in low-energy muon physics. Studies of {mu}{sup -} nuclear capture in p{mu} and the measurement of the Lamb shift in p{mu} atoms created in H{sub 2} gaseous targets are recent examples.

  12. Small-molecule control of protein function through Staudinger reduction

    NASA Astrophysics Data System (ADS)

    Luo, Ji; Liu, Qingyang; Morihiro, Kunihiko; Deiters, Alexander

    2016-11-01

    Using small molecules to control the function of proteins in live cells with complete specificity is highly desirable, but challenging. Here we report a small-molecule switch that can be used to control protein activity. The approach uses a phosphine-mediated Staudinger reduction to activate protein function. Genetic encoding of an ortho-azidobenzyloxycarbonyl amino acid using a pyrrolysyl transfer RNA synthetase/tRNACUA pair in mammalian cells enables the site-specific introduction of a small-molecule-removable protecting group into the protein of interest. Strategic placement of this group renders the protein inactive until deprotection through a bioorthogonal Staudinger reduction delivers the active wild-type protein. This developed methodology was applied to the conditional control of several cellular processes, including bioluminescence (luciferase), fluorescence (enhanced green fluorescent protein), protein translocation (nuclear localization sequence), DNA recombination (Cre) and gene editing (Cas9).

  13. Multivalent Small-Molecule Pan-RAS Inhibitors.

    PubMed

    Welsch, Matthew E; Kaplan, Anna; Chambers, Jennifer M; Stokes, Michael E; Bos, Pieter H; Zask, Arie; Zhang, Yan; Sanchez-Martin, Marta; Badgley, Michael A; Huang, Christine S; Tran, Timothy H; Akkiraju, Hemanth; Brown, Lewis M; Nandakumar, Renu; Cremers, Serge; Yang, Wan Seok; Tong, Liang; Olive, Kenneth P; Ferrando, Adolfo; Stockwell, Brent R

    2017-02-23

    Design of small molecules that disrupt protein-protein interactions, including the interaction of RAS proteins and their effectors, may provide chemical probes and therapeutic agents. We describe here the synthesis and testing of potential small-molecule pan-RAS ligands, which were designed to interact with adjacent sites on the surface of oncogenic KRAS. One compound, termed 3144, was found to bind to RAS proteins using microscale thermophoresis, nuclear magnetic resonance spectroscopy, and isothermal titration calorimetry and to exhibit lethality in cells partially dependent on expression of RAS proteins. This compound was metabolically stable in liver microsomes and displayed anti-tumor activity in xenograft mouse cancer models. These findings suggest that pan-RAS inhibition may be an effective therapeutic strategy for some cancers and that structure-based design of small molecules targeting multiple adjacent sites to create multivalent inhibitors may be effective for some proteins. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. Mind Molecules

    PubMed Central

    Snyder, Solomon H.

    2011-01-01

    Scientific styles vary tremendously. For me, research is largely about the unfettered pursuit of novel ideas and experiments that can test multiple ideas in a day, not a year, an approach that I learned from my mentor Julius “Julie” Axelrod. This focus on creative conceptualizations has been my métier since working in the summers during medical school at the National Institutes of Health, during my two years in the Axelrod laboratory, and throughout my forty-five years at Johns Hopkins University School of Medicine. Equally important has been the “high” that emerges from brainstorming with my students. Nothing can compare with the eureka moments when, together, we sense new insights and, better yet, when high-risk, high-payoff experiments succeed. Although I have studied many different questions over the years, a common theme emerges: simple biochemical approaches to understanding molecular messengers, usually small molecules. Equally important has been identifying, purifying, and cloning the messengers' relevant biosynthetic, degradative, or target proteins, at all times seeking potential therapeutic relevance in the form of drugs. In the interests of brevity, this Reflections article is highly selective, and, with a few exceptions, literature citations are only of findings of our laboratory that illustrate notable themes. PMID:21543333

  15. Positronium ions and molecules

    NASA Technical Reports Server (NTRS)

    Ho, Y. K.

    1990-01-01

    Recent theoretical studies on positronium ions and molecules are discussed. A positronium ion is a three particle system consisting of two electrons in singlet spin state, and a positron. Recent studies include calculations of its binding energy, positron annihilation rate, and investigations of its doubly excited resonant states. A positronium molecule is a four body system consisting of two positrons and two electrons in an overall singlet spin state. The recent calculations of its binding energy against the dissociation into two positronium atoms, and studies of auto-detaching states in positronium molecules are discussed. These auto-dissociating states, which are believed to be part of the Rydberg series as a result of a positron attaching to a negatively charged positronium ion, Ps-, would appear as resonances in Ps-Ps scattering.

  16. JPRS report: Nuclear developments, [October 6, 1989

    SciTech Connect

    1989-10-06

    Partial contents of this report include: Nuclear Weapons; Nuclear Development; Nuclear Power Plant; Uranium; Missiles; Space Firm Protested; Satellite; Rocket Launching; Nuclear Submarine; Environmental; Radioactivity; Radiation Accident; and Tritium Sparks.

  17. Mn8 and Mn16 clusters from the use of 2-(hydroxymethyl)pyridine, and comparison with the products from bulkier chelates: a new high nuclearity single-molecule magnet.

    PubMed

    Taguchi, Taketo; Wernsdorfer, Wolfgang; Abboud, Khalil A; Christou, George

    2010-11-15

    The synthesis, crystal structures, and magnetochemical characterization of two new Mn clusters [Mn(8)O(2)(O(2)CPh)(10)(hmp)(4)(MeOH)(2)] (1; 6Mn(II), 2Mn(III)) and [Mn(16)O(8)(OH)(2)(O(2)CPh)(12)(hmp)(10)(H(2)O)(2)](O(2)CPh)(2) (2; 6Mn(II), 10Mn(III)) are reported. They were obtained from the use of 2-(hydroxymethyl)pyridine (hmpH) under the same reaction conditions but differing in the presence or absence of added base. Thus, the reaction of hmpH with Mn(O(2)CPh)(2) in CH(2)Cl(2)/MeOH led to isolation of octanuclear complex 1, whereas the analogous reaction in the presence of NEt(3) gave hexadecanuclear complex 2. Complexes 1 and 2 possess either very rare or unprecedented core structures that are related to each other: that of 1 can be described as a linked pair of incomplete [Mn(4)O(3)] cubanes, while that of 2 consists of a linked pair of complete [Mn(4)O(4)] cubanes, on either side of which is attached a tetrahedral [Mn(4)(μ(4)-O)] unit. Solid-state direct current (dc) and alternating current (ac) magnetic susceptibility measurements on 1 and 2 establish that they possess S = 5 and 8 ground states, respectively. Complex 2 exhibits frequency-dependent out-of-phase (χ(M)") ac susceptibility signals at temperatures below 3 K suggestive of a single-molecule magnet (SMM). Magnetization versus applied dc field sweeps on single crystals of 2·10MeOH down to 0.04 K exhibited hysteresis, confirming 2 to be a new SMM. Comparison of the structure of 2 (Mn(16)) with Mn(12) or Mn(6) clusters previously obtained under the same reaction conditions but with two Me or two Ph groups, respectively, added next to the alkoxide O atom of hmp(-) indicate their influence on the nuclearity and structure of the products as being due to the overall bulk of the chelate plus the decreased ability of the O atom to bridge.

  18. Characterization of nuclear factor of activated T-cells-c3 (NFATc3) and gene expression of upstream-downstream signaling molecules in response to immunostimulants in Pacific red snapper cells.

    PubMed

    Angulo, Carlos; Alamillo, Erika; Ascencio, Felipe; Reyes-Becerril, Martha

    2017-10-03

    The nuclear factor of activated T cells (NFAT) proteins have crucial roles in the development and function of the immune system since they not only regulate activation of T cells but are also involved in the control of thymocyte development and T-cell differentiation. In this study, NFATc3 was characterized from the Pacific red snapper, Lutjanus peru. LpNFAtc3, which contains an open reading of 3300 bp frame coding for a protein of 1100 aa with a predicted molecular weight of 118.52 kDa. The predicted protein showed a conserved NFAT family structure with signature motifs and domains, sharing high identity (up to 76%) compared to other fish sequences. NFATc3 gene expression was analyzed by real time-PCR in head-kidney cells (leukocytes and lymphocytes) following yeast, zymosan and Vibrio parahaemolyticus stimulation along with the expression of upstream (ILF2, ILF3 and CaN) and downstream (CD3, TCRβ, IL-6 and IL-12) molecules. This study revealed a broad expression of NFATc3 with a relative strong expression in intestine and lymphocytes. The expression of NFATc3 was differentially up-regulated after stimulation with yeast in head-kidney leukocytes and after bacterial infection in lymphocytes at 24 h. Interestingly, the yeast and zymosan were able to activate ILF2, ILF3 and CaN mRNA gene expression in both kinds of cells. On the other hand, NFAT downstream genes such as CD3, TCRβ, IL-6 and IL-12 were significantly up-regulated in leukocytes stimulated with yeast or zymosan at 12 h; however in lymphocytes, this up-regulation was detected when cells reacted to V. parahaemolyticus stimuli at 24 h. Stimulating Pacific red snapper leukocytes with immunostimulants as yeast significantly up-regulated the expression of NFATc3, and up- and down-stream molecular genes and NFATc3 lymphocytes expression were potentially involved in responses to invasion of bacterial pathogens in an early immune response. Copyright © 2017. Published by Elsevier Ltd.

  19. NUCLEAR REACTOR CONTROL SYSTEM

    DOEpatents

    Epler, E.P.; Hanauer, S.H.; Oakes, L.C.

    1959-11-01

    A control system is described for a nuclear reactor using enriched uranium fuel of the type of the swimming pool and other heterogeneous nuclear reactors. Circuits are included for automatically removing and inserting the control rods during the course of normal operation. Appropriate safety circuits close down the nuclear reactor in the event of emergency.

  20. Revitalizing Nuclear Safety Research.

    ERIC Educational Resources Information Center

    National Academy of Sciences - National Research Council, Washington, DC.

    This report covers the general issues involved in nuclear safety research and points out the areas needing detailed consideration. Topics included are: (1) "Principles of Nuclear Safety Research" (examining who should fund, who should conduct, and who should set the agenda for nuclear safety research); (2) "Elements of a Future…

  1. Revitalizing Nuclear Safety Research.

    ERIC Educational Resources Information Center

    National Academy of Sciences - National Research Council, Washington, DC.

    This report covers the general issues involved in nuclear safety research and points out the areas needing detailed consideration. Topics included are: (1) "Principles of Nuclear Safety Research" (examining who should fund, who should conduct, and who should set the agenda for nuclear safety research); (2) "Elements of a Future…

  2. Nuclear War and Science Teaching.

    ERIC Educational Resources Information Center

    Hobson, Art

    1983-01-01

    Suggests that science-related material on nuclear war be included in introductory courses. Lists nuclear war topics for physics, psychology, sociology, biology/ecology, chemistry, geography, geology/meteorology, mathematics, and medical science. Also lists 11 lectures on nuclear physics which include nuclear war topics. (JN)

  3. Nuclear War and Science Teaching.

    ERIC Educational Resources Information Center

    Hobson, Art

    1983-01-01

    Suggests that science-related material on nuclear war be included in introductory courses. Lists nuclear war topics for physics, psychology, sociology, biology/ecology, chemistry, geography, geology/meteorology, mathematics, and medical science. Also lists 11 lectures on nuclear physics which include nuclear war topics. (JN)

  4. Vibrational autoionization in polyatomic molecules.

    PubMed

    Pratt, S T

    2005-01-01

    The vibrationally autoionizing Rydberg states of small polyatomic molecules provide a fascinating laboratory in which to study fundamental nonadiabatic processes. In this review, recent results on the vibrational mode dependence of vibrational autoionization are discussed. In general, autoionization rates depend strongly on the character of the normal mode driving the process and on the electronic character of the Rydberg electron. Although quantitative calculations based on multichannel quantum defect theory are available for some polyatomic molecules, including H3, only qualitative information exists for most molecules. This review shows how qualitative information, such as Walsh diagrams along different normal coordinates of the molecule, can provide insight into the vibrational autoionization rates.

  5. Nuclear power and nuclear weapons

    SciTech Connect

    Vaughen, V.C.A.

    1983-01-01

    The proliferation of nuclear weapons and the expanded use of nuclear energy for the production of electricity and other peaceful uses are compared. The difference in technologies associated with nuclear weapons and nuclear power plants are described.

  6. Behavior of atypical amphiphilic molecules

    NASA Astrophysics Data System (ADS)

    Ko, John

    1997-08-01

    The physical behavior of several atypical amphiphilic molecules was studied in various environments including micelles, model bilayer membranes, and emulsions. The molecules under investigation were nor-chenodeoxycholic acid (nor-CDCA), ursodeoxycholic acid (UDCA), sphingosine (Sp), sphingosine hydrochloride (SpċHCl), and tetrahydrolipstatin (THL). The bile acids, nor-CDCA and UDCA, were studied using 13C-Nuclear Magnetic Resonance ([13C) -NMR) in micelles of taurocholate and in bilayers of phosphatidylcholine. The pK a values of the bile acids in each environment were determined by [13C) -NMR and are as follows: 6.08 ±.03 for nor-CDCA and 6.27 ±.01 for UDCA in micelles, and 7.04 ± 12 for nor-CDCA and 6.89 ±.05 for UDCA in vesicles. Using line shape analysis, the transbilayer movement rate at 36oC for nor-CDCA and UDCA was calculated to be 580 sec--1 and 409 sec-1, respectively. [13C) -NMR titration of Sp gave pK a values of 9.09 ±.02 in micelles and 9.69 ±.21 in bilayers. Differential scanning calorimetry (DSC) and X-ray diffraction were used to establish the Spċwater and SpċHClċwater phase diagrams. Anhydrous and hydrated samples ranging from 5- 90% water were analyzed. The DSC thermograms traced out the transition temperatures of each molecule while the X- ray diffraction patterns revealed their chain and crystalline lattice packing structures. In general, sphingosine exists as a hydrated crystal with β packing phase below 43oC and melts into an Lα phase. Sphingosine hydrochloride, however, exists as a gel phase (L_beta or /beta/sp') below 42oC that swells to 61% hydration. At low water concentrations (0-64%), a lamellar liquid crystal phase (L_alpha) is formed above the chain melting transition of 42oC. At medium concentration (65%), a Hexagonal I phase is present, and at high water concentrations (66-90%), a micellar phase is present. THL, a specific inhibitor of lipases, was analyzed with [ 13C) -NMR to study its behavior in various environments

  7. Multicomponent Density Functional Theory: Impact of Nuclear Quantum Effects on Proton Affinities and Geometries.

    PubMed

    Brorsen, Kurt R; Yang, Yang; Hammes-Schiffer, Sharon

    2017-08-03

    Nuclear quantum effects such as zero point energy play a critical role in computational chemistry and often are included as energetic corrections following geometry optimizations. The nuclear-electronic orbital (NEO) multicomponent density functional theory (DFT) method treats select nuclei, typically protons, quantum mechanically on the same level as the electrons. Electron-proton correlation is highly significant, and inadequate treatments lead to highly overlocalized nuclear densities. A recently developed electron-proton correlation functional, epc17, has been shown to provide accurate nuclear densities for molecular systems. Herein, the NEO-DFT/epc17 method is used to compute the proton affinities for a set of molecules and to examine the role of nuclear quantum effects on the equilibrium geometry of FHF(-). The agreement of the computed results with experimental and benchmark values demonstrates the promise of this approach for including nuclear quantum effects in calculations of proton affinities, pKa's, optimized geometries, and reaction paths.

  8. Nuclear rights - nuclear wrongs

    SciTech Connect

    Paul, E.F.; Miller, F.D.; Paul, J.; Ahrens, J.

    1986-01-01

    This book contains 11 selections. The titles are: Three Ways to Kill Innocent Bystanders: Some Conundrums Concerning the Morality of War; The International Defense of Liberty; Two Concepts of Deterrence; Nuclear Deterrence and Arms Control; Ethical Issues for the 1980s; The Moral Status of Nuclear Deterrent Threats; Optimal Deterrence; Morality and Paradoxical Deterrence; Immoral Risks: A Deontological Critique of Nuclear Deterrence; No War Without Dictatorship, No Peace Without Democracy: Foreign Policy as Domestic Politics; Marxism-Leninism and its Strategic Implications for the United States; Tocqueveille War.

  9. Teaching Activities on Horizontal Nuclear Proliferation.

    ERIC Educational Resources Information Center

    Zola, John

    1990-01-01

    Provides learning activities concerning the horizontal proliferation of nuclear weapons. Includes step-by-step directions for four activities: (1) the life cycle of nuclear weapons; (2) nuclear nonproliferation: pros and cons; (3) the nuclear power/nuclear weapons connection; and (4) managing nuclear proliferation. (NL)

  10. Teaching Activities on Horizontal Nuclear Proliferation.

    ERIC Educational Resources Information Center

    Zola, John

    1990-01-01

    Provides learning activities concerning the horizontal proliferation of nuclear weapons. Includes step-by-step directions for four activities: (1) the life cycle of nuclear weapons; (2) nuclear nonproliferation: pros and cons; (3) the nuclear power/nuclear weapons connection; and (4) managing nuclear proliferation. (NL)

  11. Spent Nuclear Fuel Disposition

    SciTech Connect

    Wagner, John C.

    2016-05-22

    One interdisciplinary field devoted to achieving the end-state of used nuclear fuel (UNF) through reuse and/or permanent disposal. The reuse option aims to make use of the remaining energy content in UNF and reduce the amount of long-lived radioactive materials that require permanent disposal. The planned approach in the U.S., as well as in many other countries worldwide, is direct permanent disposal in a deep geologic repository. Used nuclear fuel is fuel that has been irradiated in a nuclear reactor to the point where it is no longer capable of sustaining operational objectives. The vast majority (by mass) of UNF is from electricity generation in commercial nuclear power reactors. Furthermore, the other main source of UNF in the U.S. is the Department of Energy’s (DOE) and other federal agencies’ operation of reactors in support of federal government missions, such as materials production, nuclear propulsion, research, testing, and training. Upon discharge from a reactor, UNF emits considerable heat from radioactive decay. Some period of active on-site cooling (e.g., 2 or more years) is typically required to facilitate efficient packaging and transportation to a disposition facility. Hence, the field of UNF disposition broadly includes storage, transportation and ultimate disposition. See also: Nuclear Fission (content/nuclear-fission/458400), Nuclear Fuels (/content/nuclear-fuels/458600), Nuclear Fuel Cycle (/content/nuclear-fuel-cycle/458500), Nuclear Fuels Reprocessing (/content/nuclear-fuels-reprocessing/458700), Nuclear Power (/content/nuclear-power/459600), Nuclear Reactor (/content/nuclear-reactor/460100), Radiation (/content/radiation/566300), and Radioactive Waste Management (/content/radioactive-waste-management/568900).

  12. Spent Nuclear Fuel Disposition

    DOE PAGES

    Wagner, John C.

    2016-05-22

    One interdisciplinary field devoted to achieving the end-state of used nuclear fuel (UNF) through reuse and/or permanent disposal. The reuse option aims to make use of the remaining energy content in UNF and reduce the amount of long-lived radioactive materials that require permanent disposal. The planned approach in the U.S., as well as in many other countries worldwide, is direct permanent disposal in a deep geologic repository. Used nuclear fuel is fuel that has been irradiated in a nuclear reactor to the point where it is no longer capable of sustaining operational objectives. The vast majority (by mass) of UNFmore » is from electricity generation in commercial nuclear power reactors. Furthermore, the other main source of UNF in the U.S. is the Department of Energy’s (DOE) and other federal agencies’ operation of reactors in support of federal government missions, such as materials production, nuclear propulsion, research, testing, and training. Upon discharge from a reactor, UNF emits considerable heat from radioactive decay. Some period of active on-site cooling (e.g., 2 or more years) is typically required to facilitate efficient packaging and transportation to a disposition facility. Hence, the field of UNF disposition broadly includes storage, transportation and ultimate disposition. See also: Nuclear Fission (content/nuclear-fission/458400), Nuclear Fuels (/content/nuclear-fuels/458600), Nuclear Fuel Cycle (/content/nuclear-fuel-cycle/458500), Nuclear Fuels Reprocessing (/content/nuclear-fuels-reprocessing/458700), Nuclear Power (/content/nuclear-power/459600), Nuclear Reactor (/content/nuclear-reactor/460100), Radiation (/content/radiation/566300), and Radioactive Waste Management (/content/radioactive-waste-management/568900).« less

  13. Quantum Controlled Nuclear Fusion

    NASA Astrophysics Data System (ADS)

    Gruebele, Martin

    2017-06-01

    Laser-assisted nuclear fusion is a potential means for providing short, well-controlled particle bursts in the lab, such as neutron or alpha particle pulses. I will discuss computational results of how coherent control by shaped, amplified 800 nm laser pulses can be used to enhance the nuclear fusion cross section of diatomic molecules such as BH or DT. Quantum dynamics simulations show that a strong laser pulse can simultaneously field-bind the diatomic molecule after electron ejection, and increase the amplitude of the vibrational wave function at small internuclear distances. When VUV shaped laser pulses become available, coherent laser control may also be extended to muonic molecules such as D-mu-T, held together by muons instead of electrons. Muonic fusion has been extensively investigated for many decades, but without coherent laser control it falls slightly short of the break-evne point.

  14. Biophysical characterization of DNA binding from single molecule force measurements

    PubMed Central

    Chaurasiya, Kathy R.; Paramanathan, Thayaparan; McCauley, Micah J.; Williams, Mark C.

    2010-01-01

    Single molecule force spectroscopy is a powerful method that uses the mechanical properties of DNA to explore DNA interactions. Here we describe how DNA stretching experiments quantitatively characterize the DNA binding of small molecules and proteins. Small molecules exhibit diverse DNA binding modes, including binding into the major and minor grooves and intercalation between base pairs of double-stranded DNA (dsDNA). Histones bind and package dsDNA, while other nuclear proteins such as high mobility group proteins bind to the backbone and bend dsDNA. Single-stranded DNA (ssDNA) binding proteins slide along dsDNA to locate and stabilize ssDNA during replication. Other proteins exhibit binding to both dsDNA and ssDNA. Nucleic acid chaperone proteins can switch rapidly between dsDNA and ssDNA binding modes, while DNA polymerases bind both forms of DNA with high affinity at distinct binding sites at the replication fork. Single molecule force measurements quantitatively characterize these DNA binding mechanisms, elucidating small molecule interactions and protein function. PMID:20576476

  15. Biophysical characterization of DNA binding from single molecule force measurements

    NASA Astrophysics Data System (ADS)

    Chaurasiya, Kathy R.; Paramanathan, Thayaparan; McCauley, Micah J.; Williams, Mark C.

    2010-09-01

    Single molecule force spectroscopy is a powerful method that uses the mechanical properties of DNA to explore DNA interactions. Here we describe how DNA stretching experiments quantitatively characterize the DNA binding of small molecules and proteins. Small molecules exhibit diverse DNA binding modes, including binding into the major and minor grooves and intercalation between base pairs of double-stranded DNA (dsDNA). Histones bind and package dsDNA, while other nuclear proteins such as high mobility group proteins bind to the backbone and bend dsDNA. Single-stranded DNA (ssDNA) binding proteins slide along dsDNA to locate and stabilize ssDNA during replication. Other proteins exhibit binding to both dsDNA and ssDNA. Nucleic acid chaperone proteins can switch rapidly between dsDNA and ssDNA binding modes, while DNA polymerases bind both forms of DNA with high affinity at distinct binding sites at the replication fork. Single molecule force measurements quantitatively characterize these DNA binding mechanisms, elucidating small molecule interactions and protein function.

  16. Crown ether alcohols. 1. Crystal and molecular structure of the complex between sym-hydroxydibenzo-14-crown-4- and water molecules ((C sub 18 H sub 20 O sub 5 )ter dot 1. 25(H sub 2 O)ter dot 0. 125(CH sub 3 OH)) including interesting water-methanol channels

    SciTech Connect

    Olsher, U.; Frolow, F.; Bartsch, R.A.; Pugia, M.J.; Shoham, G. Texas Tech Univ., Lubbock Hebrew Univ. of Jerusalem )

    1989-12-20

    The synthesis and crystal structure of the title compound are described. Single-crystal x-ray structure analysis indicates 8 formula units in the unit cell of parameters a = 16.024 (1) {angstrom} and c = 13.076 (1) {angstrom}. The space group is I{bar 4}. Direct methods yielded the structure, which was refined by least-squares techniques to a final R factor of 0.038 for 1533 independent observations. Unusual water-methanol channels are found in this structure. The crystal packing of the complex includes hydrophilic water-methanol channels which are surrounded by hydrophobic cylinders consisting mainly of benzo rings and methylene groups. The crystal structure provides a model for the encapsulation of water molecules by hydrophobic regions with potential application for the formation of hydrophilic pores in biological bilayers.

  17. Britain`s nuclear quandary

    SciTech Connect

    1994-07-01

    This article is review of energy policy in the United Kingdom, in particular, the British government`s review of the nuclear industry. Major topics of this review include: (1) The economic viability of new nuclear stations, (2) The privitization of the nuclear industry, (3) Nuclear waste disposal, and (4) Liabilities associated with decommissioning.

  18. Nuclear weapons and international law

    SciTech Connect

    Pogany, I.

    1987-01-01

    Using two different perspectives, this collection of essays addresses the central legal question of whether the manufacture, deployment, and potential use of nuclear weapons is lawful. In addition, individual chapters focus on a variety of topical issues, including nuclear weapon free zones, nuclear testing, international law and regulations, nuclear weapons and nonproliferation, anti-ballistic missile systems, and the Strategic Defense Initiative.

  19. Nuclear Medicine

    PubMed Central

    Streek, Penny Vande; Carretta, Robert; Weiland, Frederick L.

    1994-01-01

    The Council on Scientific Affairs of the California Medical Association presents the following epitomes of progress in nuclear medicine. Each item, in the judgment of a panel of knowledgeable physicians, has recently become reasonably firmly established, both as to scientific fact and clinical importance. The items are presented in simple epitome, and an authoritative reference, both to the item itself and to the subject as a whole, is generally given for those who may be unfamiliar with a particular item. The purpose is to assist busy practitioners, students, researchers, and scholars to stay abreast of progress in medicine, whether in their own field of special interest or another. The epitomes included here were selected by the Advisory Panel to the Section on Nuclear Medicine of the California Medical Association, and the summaries were prepared under the direction of Dr Lyons and the panel. PMID:7529452

  20. Nuclear Medicine.

    ERIC Educational Resources Information Center

    Badawi, Ramsey D.

    2001-01-01

    Describes the use of nuclear medicine techniques in diagnosis and therapy. Describes instrumentation in diagnostic nuclear medicine and predicts future trends in nuclear medicine imaging technology. (Author/MM)

  1. Nuclear ventriculography

    MedlinePlus

    ... ventriculography (RNV); Multiple gate acquisition scan (MUGA); Nuclear cardiology; Cardiomyopathy - nuclear ventriculography ... 56. Udelson JE, Dilsizian V, Bonow RO. Nuclear cardiology. In: Bonow RO, Mann DL, Zipes DP, Libby ...

  2. Nuclear Medicine.

    ERIC Educational Resources Information Center

    Badawi, Ramsey D.

    2001-01-01

    Describes the use of nuclear medicine techniques in diagnosis and therapy. Describes instrumentation in diagnostic nuclear medicine and predicts future trends in nuclear medicine imaging technology. (Author/MM)

  3. Nuclear data for nuclear transmutation

    SciTech Connect

    Harada, Hideo

    2009-05-04

    Current status on nuclear data for the study of nuclear transmutation of radioactive wastes is reviewed, mainly focusing on neutron capture reactions. It is stressed that the highest-precision frontier research in nuclear data measurements should be a key to satisfy the target accuracies on the nuclear data requested for realizing the nuclear transmutation.

  4. Nuclear data for nuclear transmutation

    NASA Astrophysics Data System (ADS)

    Harada, Hideo

    2009-05-01

    Current status on nuclear data for the study of nuclear transmutation of radioactive wastes is reviewed, mainly focusing on neutron capture reactions. It is stressed that the highest-precision frontier research in nuclear data measurements should be a key to satisfy the target accuracies on the nuclear data requested for realizing the nuclear transmutation.

  5. 34 CFR 303.15 - Include; including.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 34 Education 2 2010-07-01 2010-07-01 false Include; including. 303.15 Section 303.15 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF SPECIAL EDUCATION AND REHABILITATIVE SERVICES, DEPARTMENT OF EDUCATION EARLY INTERVENTION PROGRAM FOR INFANTS AND TODDLERS WITH...

  6. 34 CFR 303.15 - Include; including.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 34 Education 2 2011-07-01 2010-07-01 true Include; including. 303.15 Section 303.15 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF SPECIAL EDUCATION AND REHABILITATIVE SERVICES, DEPARTMENT OF EDUCATION EARLY INTERVENTION PROGRAM FOR INFANTS AND TODDLERS WITH...

  7. Introduction to nucleocytoplasmic transport: molecules and mechanisms.

    PubMed

    Peters, Reiner

    2006-01-01

    Nucleocytoplasmic transport, the exchange of matter between nucleus and cytoplasm, plays a fundamental role in human and other eukaryotic cells, affecting almost every aspect of health and disease. The only gate for the transport of small and large molecules as well as supramolecular complexes between nucleus and cytoplasm is the nuclear pore complex (NPC). The NPC is not a normal membrane transport protein (transporter). Composed of 500 to 1000 peptide chains, the NPC features a mysterious functional duality. For most molecules, it constitutes a molecular sieve with a blurred cutoff at approx 10 nm, but for molecules binding to phenylalanine-glycine (FG) motifs, the NPC appears to be a channel of approx 50 nm diameter, permitting bidirectional translocation at high speed. To achieve this, the NPC cooperates with soluble factors, the nuclear transport receptors, which shuttle between nuclear contents and cytoplasm. Here, we provide a short introduction to nucleocytoplasmic transport by describing first the structure and composition of the nuclear pore complex. Then, mechanisms of nucleocytoplasmic transport are discussed. Finally, the still essentially unresolved mechanisms by which nuclear transport receptors and transport complexes are translocated through the nuclear pore complex are considered, and a novel translocation model is suggested.

  8. Resonances in Positron-molecule Interactions

    NASA Astrophysics Data System (ADS)

    Surko, C. M.

    2006-05-01

    The development of cold, trap-based beams has enabled high-resolution, energy-resolved studies of positron scattering and annihilation processes [1]. This talk focuses on three topics in this area. For hydrocarbon molecules such as alkanes (CnH2n+2), giant enhancements in annihilation rates are observed due to vibrational Feshbach resonances. The dependence of the rates on positron energy provides evidence that positrons bind to these molecules and a measure of the binding energies [1]. Recent results include evidence for a second, ``positronically excited'' bound state and new data for the methane series, CH3X, where X is a halogen. Other ``resonance-like features'' are sharp increases in the near-threshold electronic excitation cross sections for CO and N2 [2], and in the vibrational excitation cross sections for CO, CO2 and CH4 [3, 4]. Outstanding questions and the relationship of these observations to available theoretical predictions will be discussed.1. C. M. Surko, G. F. Gribakin, and S. J. Buckman, J. Phys. B 38, R57 (2005).2. J. P. Marler and C. M. Surko, Phys. Rev. A 72, 062713 (2005).3. J. P. Marler and C. M. Surko, Phys. Rev. A 72, 062702 (2005).4. J. P. Marler, G. F. Gribakin and C. M. Surko, Nuclear Instrum. and Meth. B, in press (2006).

  9. Quantum transport through aromatic molecules

    SciTech Connect

    Ojeda, J. H.; Rey-González, R. R.; Laroze, D.

    2013-12-07

    In this paper, we study the electronic transport properties through aromatic molecules connected to two semi-infinite leads. The molecules are in different geometrical configurations including arrays. Using a nearest neighbor tight-binding approach, the transport properties are analyzed into a Green's function technique within a real-space renormalization scheme. We calculate the transmission probability and the Current-Voltage characteristics as a function of a molecule-leads coupling parameter. Our results show different transport regimes for these systems, exhibiting metal-semiconductor-insulator transitions and the possibility to employ them in molecular devices.

  10. Nuclear pore complexes and regulation of gene expression.

    PubMed

    Raices, Marcela; D'Angelo, Maximiliano A

    2017-01-11

    Nuclear pore complexes (NPCs), are large multiprotein channels that penetrate the nuclear envelope connecting the nucleus to the cytoplasm. Accumulating evidence shows that besides their main role in regulating the exchange of molecules between these two compartments, NPCs and their components also play important transport-independent roles, including gene expression regulation, chromatin organization, DNA repair, RNA processing and quality control, and cell cycle control. Here, we will describe the recent findings about the role of these structures in the regulation of gene expression.

  11. Xenopus laevis neuronal cell adhesion molecule (nrcam): plasticity of a CAM in the developing nervous system.

    PubMed

    Lokapally, Ashwin; Metikala, Sanjeeva; Hollemann, Thomas

    2017-01-01

    Neuron-glial-related cell adhesion molecule (NRCAM) is a neuronal cell adhesion molecule of the L1 immunoglobulin superfamily, which plays diverse roles during nervous system development including axon growth and guidance, synapse formation, and formation of the myelinated nerve. Perturbations in NRCAM function cause a wide variety of disorders, which can affect wiring and targeting of neurons, or cause psychiatric disorders as well as cancers through abnormal modulation of signaling events. In the present study, we characterize the Xenopus laevis homolog of nrcam. Expression of Xenopus nrcam is most abundant along the dorsal midline throughout the developing brain and in the outer nuclear layer of the retina.

  12. Two-dimensional NMR spectroscopy: correlated, homonuclear-correlated, and nuclear Overhauser spectroscopy. January 1975-December 1988 (Citations from the INSPEC: Information Services for the Physics and Engineering Communities data base). Report for January 1975-December 1988

    SciTech Connect

    Not Available

    1988-12-01

    This bibliography contains citations concerning the enhanced analytical techniques of two-dimensional nuclear magnetic resonance (2-D NMR). Applications to specific molecules, biomolecules, and compounds as well as comparisons of three 2-D NMR techniques: correlated spectroscopy (COSY), nuclear Overhauser (NOSEY), and homonuclear-correlated spectroscopy (HOMCOR). (Contains 190 citations fully indexed and including a title list.)

  13. History of Nuclear India

    NASA Astrophysics Data System (ADS)

    Chaturvedi, Ram

    2000-04-01

    India emerged as a free and democratic country in 1947, and entered into the nuclear age in 1948 by establishing the Atomic Energy Commission (AEC), with Homi Bhabha as the chairman. Later on the Department of Atomic Energy (DAE) was created under the Office of the Prime Minister Jawahar Lal Nehru. Initially the AEC and DAE received international cooperation, and by 1963 India had two research reactors and four nuclear power reactors. In spite of the humiliating defeat in the border war by China in 1962 and China's nuclear testing in 1964, India continued to adhere to the peaceful uses of nuclear energy. On May 18, 1974 India performed a 15 kt Peaceful Nuclear Explosion (PNE). The western powers considered it nuclear weapons proliferation and cut off all financial and technical help, even for the production of nuclear power. However, India used existing infrastructure to build nuclear power reactors and exploded both fission and fusion devices on May 11 and 13, 1998. The international community viewed the later activity as a serious road block for the Non-Proliferation Treaty and the Comprehensive Test Ban Treaty; both deemed essential to stop the spread of nuclear weapons. India considers these treaties favoring nuclear states and is prepared to sign if genuine nuclear disarmament is included as an integral part of these treaties.

  14. Physics of Molecules

    NASA Astrophysics Data System (ADS)

    Williams, D.; Murdin, P.

    2000-11-01

    Many varieties of molecule have been detected in the Milky Way and in other galaxies. The processes by which these molecules are formed and destroyed are now broadly understood (see INTERSTELLAR CHEMISTRY). These molecules are important components of galaxies in two ways. Firstly, radiation emitted by molecules enables us to trace the presence of diffuse gas, to infer its physical properties and ...

  15. Nuclear imaging in pediatrics

    SciTech Connect

    Siddiqui, A.R.

    1985-01-01

    The author's intent is to familiarize practicing radiologists with the technical aspects and interpretation of nuclear medicine procedures in children and to illustrate the indications for nuclear medicine procedures in pediatric problems. Pediatric doses, dosimetry, sedation, and injection techniques, organ systems, oncology and infection, testicular scanning and nuclear crystography, pediatric endocrine and skeletal systems, ventilation and perfusion imaging of both congenital and acquired pediatric disorders, cardiovascular problems, gastrointestinal, hepatobiliary, reticuloendothelial studies, and central nervous system are all topics which are included and discussed.

  16. Nuclear Terms: a glossary

    SciTech Connect

    Freiwald, David A.

    1981-05-31

    This booklet is a revision of Nuclear Terms: A Glossary, published in 1967 by the United States Atomic Energy Commission. New fields, such as laser fusion and laser isotope separation, are included and nuclear weapons terms are deleted. Thus, it is a glossary for nuclear fission and fusion science and for commercial applications. David A. Freiwald, Frank C. DiLuzio, and Leslie M. Redman prepared this revised glossary. Contributions were made by other members of the Los Alamos National Laboratory staff.

  17. Nuclear Security for Floating Nuclear Power Plants

    SciTech Connect

    Skiba, James M.; Scherer, Carolynn P.

    2015-10-13

    Recently there has been a lot of interest in small modular reactors. A specific type of these small modular reactors (SMR,) are marine based power plants called floating nuclear power plants (FNPP). These FNPPs are typically built by countries with extensive knowledge of nuclear energy, such as Russia, France, China and the US. These FNPPs are built in one country and then sent to countries in need of power and/or seawater desalination. Fifteen countries have expressed interest in acquiring such power stations. Some designs for such power stations are briefly summarized. Several different avenues for cooperation in FNPP technology are proposed, including IAEA nuclear security (i.e. safeguards), multilateral or bilateral agreements, and working with Russian design that incorporates nuclear safeguards for IAEA inspections in non-nuclear weapons states

  18. Polarized nuclear target based on parahydrogen induced polarization

    SciTech Connect

    D. Budker, M.P. Ledbetter, S. Appelt, L.S. Bouchard, B. Wojtsekhowski

    2012-12-01

    We discuss a novel concept of a polarized nuclear target for accelerator fixed-target scattering experiments, which is based on parahydrogen induced polarization (PHIP). One may be able to reach a 33% free-proton polarization in the ethane molecule. The potential advantages of such a target include operation at zero magnetic field, fast ({approx}100 HZ) polarization oscillation (akin to polarization reversal), and operation with large intensity of an electron beam.

  19. Report Card on Nuclear Power

    ERIC Educational Resources Information Center

    Novick, Sheldon

    1974-01-01

    Problems facing the nuclear power industry include skyrocketing construction costs, technical failures, fuel scarcity, power plant safety, and the disposal of nuclear wastes. Possible solutions include: reductions in nuclear power plant construction, a complete moratorium on new plant construction, the construction of fast breeder reactors and the…

  20. Report Card on Nuclear Power

    ERIC Educational Resources Information Center

    Novick, Sheldon

    1974-01-01

    Problems facing the nuclear power industry include skyrocketing construction costs, technical failures, fuel scarcity, power plant safety, and the disposal of nuclear wastes. Possible solutions include: reductions in nuclear power plant construction, a complete moratorium on new plant construction, the construction of fast breeder reactors and the…

  1. Uranium-mediated activation of small molecules.

    PubMed

    Arnold, Polly L

    2011-08-28

    Molecular complexes of uranium are capable of activating a range of industrially and economically important small molecules such as CO, CO(2), and N(2); new and often unexpected reactions provide insight into an element that needs to be well-understood if future clean-energy solutions are to involve nuclear power.

  2. Single Molecule Electronics and Devices

    PubMed Central

    Tsutsui, Makusu; Taniguchi, Masateru

    2012-01-01

    The manufacture of integrated circuits with single-molecule building blocks is a goal of molecular electronics. While research in the past has been limited to bulk experiments on self-assembled monolayers, advances in technology have now enabled us to fabricate single-molecule junctions. This has led to significant progress in understanding electron transport in molecular systems at the single-molecule level and the concomitant emergence of new device concepts. Here, we review recent developments in this field. We summarize the methods currently used to form metal-molecule-metal structures and some single-molecule techniques essential for characterizing molecular junctions such as inelastic electron tunnelling spectroscopy. We then highlight several important achievements, including demonstration of single-molecule diodes, transistors, and switches that make use of electrical, photo, and mechanical stimulation to control the electron transport. We also discuss intriguing issues to be addressed further in the future such as heat and thermoelectric transport in an individual molecule. PMID:22969345

  3. Nuclear glycogen and glycogen synthase kinase 3.

    PubMed

    Ragano-Caracciolo, M; Berlin, W K; Miller, M W; Hanover, J A

    1998-08-19

    Glycogen is the principal storage form of glucose in animal cells. It accumulates in electron-dense cytoplasmic granules and is synthesized by glycogen synthase (GS), the rate-limiting enzyme of glycogen deposition. Glycogen synthase kinase-3 (GSK-3) is a protein kinase that phosphorylates GS. Two nearly identical forms of GSK-3 exist: GSK-3 alpha and GSK-3 beta. Both are constitutively active in resting cells and their activity can be modulated by hormones and growth factors. GSK-3 is implicated in the regulation of many physiological responses in mammalian cells by phosphorylating substrates including neuronal cell adhesion molecule, neurofilaments, synapsin I, and tau. Recent observations point to functions for glycogen and glycogen metabolism in the nucleus. GSK-3 phosphorylates several transcription factors, and we have recently shown that it modifies the major nuclear pore protein p62. It also regulates PK1, a protein kinase required for maintaining the interphase state and for DNA replication in cycling Xenopus egg extracts. Recently, glycogen was shown to be required for nuclear reformation in vitro using ovulated Xenopus laevis egg lysates. Because neither glycogen nor GSK-3 has been localized to the nuclear envelope or intranuclear sites, glycogen and GSK-3 activites were measured in rat liver nuclei and nuclear reformation extracts. Significant quantities of glycogen-like material co-purified with the rat-liver nuclear envelope. GSK-3 is also highly enriched in the glycogen pellet of egg extracts of Xenopus that is required for nuclear assembly in vitro. Based on the finding that enzymes of glycogen metabolism copurify with glycogen, we propose that glycogen may serve a structural role as a scaffold for nuclear assembly and sequestration of critical kinases and phosphatases in the nucleus. Copyright 1998 Academic Press.

  4. Education and the Threat of Nuclear War.

    ERIC Educational Resources Information Center

    Markusen, Eric

    1982-01-01

    Discusses the role of education in preventing nuclear war. Includes information on projects and organizations involved in educating children and youth about nuclear war and profiles of organizations that have been promoting nuclear war education at colleges and universities. (JN)

  5. Education and the Threat of Nuclear War.

    ERIC Educational Resources Information Center

    Markusen, Eric

    1982-01-01

    Discusses the role of education in preventing nuclear war. Includes information on projects and organizations involved in educating children and youth about nuclear war and profiles of organizations that have been promoting nuclear war education at colleges and universities. (JN)

  6. Nonconventional applications of nuclear technology to space

    SciTech Connect

    Woodall, D.M.; Dolan, T.J. )

    1991-01-01

    The application of nuclear energy to power and propulsion to support President Bush's Space Exploration Initiative (SEI) has received considerable technical attention. This paper discusses the application of other nuclear technologies in space, including nuclear fusion, advanced accelerator research, antimatter research, nuclear technologies for exploration and mining, and nuclear astronomy.

  7. Comprehensive Nuclear Materials

    SciTech Connect

    Konings, Dr. Rudy J. M.; Allen, Todd R.; Stoller, Roger E; Yamanaka, Prof. Shinsuke

    2012-01-01

    This book encompasses a rich seam of current information on the vast and multidisciplinary field of nuclear materials employed in fission and prototype fusion systems. Discussion includes both historical and contemporary international research in nuclear materials, from Actinides to Zirconium alloys, from the worlds leading scientists and engineers. Synthesizes pertinent current science to support the selection, assessment, validation and engineering of materials in extreme nuclear environments. The work discusses the major classes of materials suitable for usage in nuclear fission, fusion reactors and high power accelerators, and for diverse functions in fuels, cladding, moderator and control materials, structural, functional, and waste materials.

  8. Living with Nuclear Weapons - Avoiding Nuclear War

    DTIC Science & Technology

    1989-06-01

    00 LIVING ’V1I4. NUCL EAR WEAPONS -AVOIDING NUCLEAR W~AR C. Pr~ston Niblack ..une -8 P-75-7 The RAND ",rporation Papers are issued by The RAND...necessarily shared by RAND or its research sponsors. The RAND Corporation. 1700 Main Street, P ) Bix 213t8, Santa Monica, CA 90406- � LIVING WITH NUCLEAR...is p"etty impressive. Still, nuclear weapons exist . and that alone is very womsome to many people. including to all of us here, because as long as they

  9. TRAINING NUCLEAR TECHNICIANS.

    ERIC Educational Resources Information Center

    KOVNER, EDGAR A.

    PROBLEMS CONFRONTED BY PLANNERS OF NUCLEAR PROGRAMS AT THE TECHNICIAN LEVEL INCLUDE (1) LACK OF PRECEDENT IN CURRICULUM, COURSE OUTLINES, AND GRADUATE PLACEMENT, (2) DIFFICULTY IN DETERMINING COSTS OF LABORATORY CONSTRUCTION, EQUIPMENT, AND OPERATION, AND (3) REQUIREMENT OF ATOMIC ENERGY COMMISSION LICENSES IN NUCLEAR OCCUPATIONS. A 92-SEMESTER…

  10. Clinical Nuclear Pharmacy Clerkship

    ERIC Educational Resources Information Center

    Dunson, George L.; Christopherson, William J., Jr.

    1977-01-01

    The School of Pharmacy, University of the Pacific, and the Pharmacy Service, Letterman Army Medical Center, initiated a 15-week clinical nuclear pharmacy clerkship in 1975. It includes basic nuclear medical science, technical competency, professional competency, and special interest emphasis. (LBH)

  11. Clinical Nuclear Pharmacy Clerkship

    ERIC Educational Resources Information Center

    Dunson, George L.; Christopherson, William J., Jr.

    1977-01-01

    The School of Pharmacy, University of the Pacific, and the Pharmacy Service, Letterman Army Medical Center, initiated a 15-week clinical nuclear pharmacy clerkship in 1975. It includes basic nuclear medical science, technical competency, professional competency, and special interest emphasis. (LBH)

  12. Nuclear Science References Database

    SciTech Connect

    Pritychenko, B.; Běták, E.; Singh, B.; Totans, J.

    2014-06-15

    The Nuclear Science References (NSR) database together with its associated Web interface, is the world's only comprehensive source of easily accessible low- and intermediate-energy nuclear physics bibliographic information for more than 210,000 articles since the beginning of nuclear science. The weekly-updated NSR database provides essential support for nuclear data evaluation, compilation and research activities. The principles of the database and Web application development and maintenance are described. Examples of nuclear structure, reaction and decay applications are specifically included. The complete NSR database is freely available at the websites of the National Nuclear Data Center (http://www.nndc.bnl.gov/nsr) and the International Atomic Energy Agency (http://www-nds.iaea.org/nsr)

  13. Watching single molecules dance

    NASA Astrophysics Data System (ADS)

    Mehta, Amit Dinesh

    Molecular motors convert chemical energy, from ATP hydrolysis or ion flow, into mechanical motion. A variety of increasingly precise mechanical probes have been developed to monitor and perturb these motors at the single molecule level. Several outstanding questions can be best approached at the single molecule level. These include: how far does a motor progress per energy quanta consumed? how does its reaction cycle respond to load? how many productive catalytic cycles can it undergo per diffusional encounter with its track? and what is the mechanical stiffness of a single molecule connection? A dual beam optical trap, in conjunction with in vitro ensemble motility assays, has been used to characterize two members of the myosin superfamily: muscle myosin II and chick brain myosin V. Both move the helical polymer actin, but myosin II acts in large ensembles to drive muscle contraction or cytokinesis, while myosin V acts in small numbers to transport vesicles. An optical trapping apparatus was rendered sufficiently precise to identify a myosin working stroke with 1nm or so, barring systematic errors such as those perhaps due to random protein orientations. This and other light microscopic motility assays were used to characterize myosin V: unlike myosin II this vesicle transport protein moves through many increments of travel while remaining strongly bound to a single actin filament. The step size, stall force, and travel distance of myosin V reveal a remarkably efficient motor capable of moving along a helical track for over a micrometer without significantly spiraling around it. Such properties are fully consistent with the putative role of an organelle transport motor, present in small numbers to maintain movement over long ranges relative to cellular size scales. The contrast between myosin II and myosin V resembles that between a human running on the moon and one walking on earth, where the former allows for faster motion when in larger ensembles but for less

  14. On the Mass of Atoms in Molecules: Beyond the Born-Oppenheimer Approximation

    NASA Astrophysics Data System (ADS)

    Scherrer, Arne; Agostini, Federica; Sebastiani, Daniel; Gross, E. K. U.; Vuilleumier, Rodolphe

    2017-07-01

    Describing the dynamics of nuclei in molecules requires a potential energy surface, which is traditionally provided by the Born-Oppenheimer or adiabatic approximation. However, we also need to assign masses to the nuclei. There, the Born-Oppenheimer picture does not account for the inertia of the electrons, and only bare nuclear masses are considered. Nowadays, experimental accuracy challenges the theoretical predictions of rotational and vibrational spectra and requires the participation of electrons in the internal motion of the molecule. More than 80 years after the original work of Born and Oppenheimer, this issue has still not been solved, in general. Here, we present a theoretical and numerical framework to address this problem in a general and rigorous way. Starting from the exact factorization of the electron-nuclear wave function, we include electronic effects beyond the Born-Oppenheimer regime in a perturbative way via position-dependent corrections to the bare nuclear masses. This maintains an adiabaticlike point of view: The nuclear degrees of freedom feel the presence of the electrons via a single potential energy surface, whereas the inertia of electrons is accounted for and the total mass of the system is recovered. This constitutes a general framework for describing the mass acquired by slow degrees of freedom due to the inertia of light, bounded particles; thus, it is applicable not only in electron-nuclear systems but in light-heavy nuclei or ions as well. We illustrate this idea with a model of proton transfer, where the light particle is the proton and the heavy particles are the oxygen atoms to which the proton is bounded. Inclusion of the light-particle inertia allows us to gain orders of magnitude in accuracy. The electron-nuclear perspective is adopted, instead, to calculate position-dependent mass corrections using density functional theory for a few polyatomic molecules at their equilibrium geometry. These data can serve as input for the

  15. Core-mass nonadiabatic corrections to molecules: H2, H2+, and isotopologues.

    PubMed

    Diniz, Leonardo G; Alijah, Alexander; Mohallem, José Rachid

    2012-10-28

    For high-precision calculations of rovibrational states of light molecules, it is essential to include non-adiabatic corrections. In the absence of crossings of potential energy surfaces, they can be incorporated in a single surface picture through coordinate-dependent vibrational and rotational reduced masses. We present a compact method for their evaluation and relate in particular the vibrational mass to a well defined nuclear core mass derived from a Mulliken analysis of the electronic density. For the rotational mass we propose a simple, but very effective parametrization. The use of these masses in the nuclear Schrödinger equation yields numerical data for the corrections of a much higher quality than can be obtained with optimized constant masses, typically better than 0.1 cm(-1). We demonstrate the method for H(2), H(2)(+), and singly deuterated isotopologues. Isotopic asymmetry does not present any particular difficulty. Generalization to polyatomic molecules is straightforward.

  16. Nuclear Chemistry.

    ERIC Educational Resources Information Center

    Chemical and Engineering News, 1979

    1979-01-01

    Provides a brief review of the latest developments in nuclear chemistry. Nuclear research today is directed toward increased activity in radiopharmaceuticals and formation of new isotopes by high-energy, heavy-ion collisions. (Author/BB)

  17. Nuclear Winter.

    ERIC Educational Resources Information Center

    Ehrlich, Anne

    1984-01-01

    "Nuclear Winter" was recently coined to describe the climatic and biological effects of a nuclear war. These effects are discussed based on models, simulations, scenarios, and projections. Effects on human populations are also considered. (JN)

  18. Nuclear Medicine

    MedlinePlus

    ... Home » Science Education » Science Topics » Nuclear Medicine SCIENCE EDUCATION SCIENCE EDUCATION Science Topics Resource Links for General Public Resource ... Related Documents: Nuclear Medicine Fact Sheet.pdf SCIENCE EDUCATION Science Topics Resource Links for General Public Resource ...

  19. Nuclear Chemistry.

    ERIC Educational Resources Information Center

    Chemical and Engineering News, 1979

    1979-01-01

    Provides a brief review of the latest developments in nuclear chemistry. Nuclear research today is directed toward increased activity in radiopharmaceuticals and formation of new isotopes by high-energy, heavy-ion collisions. (Author/BB)

  20. Nuclear Winter.

    ERIC Educational Resources Information Center

    Ehrlich, Anne

    1984-01-01

    "Nuclear Winter" was recently coined to describe the climatic and biological effects of a nuclear war. These effects are discussed based on models, simulations, scenarios, and projections. Effects on human populations are also considered. (JN)

  1. Utilizing Yeast Surface Human Proteome Display Libraries to Identify Small Molecule-Protein Interactions.

    PubMed

    Bidlingmaier, Scott; Liu, Bin

    2015-01-01

    The identification of proteins that interact with small bioactive molecules is a critical but often difficult and time-consuming step in understanding cellular signaling pathways or molecular mechanisms of drug action. Numerous methods for identifying small molecule-interacting proteins have been developed and utilized, including affinity-based purification followed by mass spectrometry analysis, protein microarrays, phage display, and three-hybrid approaches. Although all these methods have been used successfully, there remains a need for additional techniques for analyzing small molecule-protein interactions. A promising method for identifying small molecule-protein interactions is affinity-based selection of yeast surface-displayed human proteome libraries. Large and diverse libraries displaying human protein fragments on the surface of yeast cells have been constructed and subjected to FACS-based enrichment followed by comprehensive exon microarray-based output analysis to identify protein fragments with affinity for small molecule ligands. In a recent example, a proteome-wide search has been successfully carried out to identify cellular proteins binding to the signaling lipids PtdIns(4,5)P2 and PtdIns(3,4,5)P3. Known phosphatidylinositide-binding proteins such as pleckstrin homology domains were identified, as well as many novel interactions. Intriguingly, many novel nuclear phosphatidylinositide-binding proteins were discovered. Although the existence of an independent pool of nuclear phosphatidylinositides has been known about for some time, their functions and mechanism of action remain obscure. Thus, the identification and subsequent study of nuclear phosphatidylinositide-binding proteins is expected to bring new insights to this important biological question. Based on the success with phosphatidylinositides, it is expected that the screening of yeast surface-displayed human proteome libraries will be of general use for the discovery of novel small

  2. Development of novel small molecules for imaging and drug release

    NASA Astrophysics Data System (ADS)

    Cao, Yanting

    Small organic molecules, including small molecule based fluorescent probes, small molecule based drugs or prodrugs, and smart multifunctional fluorescent drug delivery systems play important roles in biological research, drug discovery, and clinical practices. Despite the significant progress made in these fields, the development of novel and diverse small molecules is needed to meet various demands for research and clinical applications. My Ph.D study focuses on the development of novel functional molecules for recognition, imaging and drug release. In the first part, a turn-on fluorescent probe is developed for the detection of intracellular adenosine-5'-triphosphate (ATP) levels based on multiplexing recognitions. Considering the unique and complicated structure of ATP molecules, a fluorescent probe has been implemented with improved sensitivity and selectivity due to two synergistic binding recognitions by incorporating of 2, 2'-dipicolylamine (Dpa)-Zn(II) for targeting of phospho anions and phenylboronic acid group for cis-diol moiety. The novel probe is able to detect intracellular ATP levels in SH-SY5Y cells. Meanwhile, the advantages of multiplexing recognition design concept have been demonstrated using two control molecules. In the second part, a prodrug system is developed to deliver multiple drugs within one small molecule entity. The prodrug is designed by using 1-(2-nitrophenyl)ethyl (NPE) as phototrigger, and biphenol biquaternary ammonium as the prodrug. With controlled photo activation, both DNA cross-linking agents mechlorethamine and o-quinone methide are delivered and released at the preferred site, leading to efficient DNA cross-links formation and cell death. The prodrug shows negligible cytotoxicity towards normal skin cells (Hekn cells) with and without UV activation, but displays potent activity towards cancer cells (HeLa cells) upon UV activation. The multiple drug release system may hold a great potential for practical application. In the

  3. Nuclear weapons, nuclear effects, nuclear war

    SciTech Connect

    Bing, G.F.

    1991-08-20

    This paper provides a brief and mostly non-technical description of the militarily important features of nuclear weapons, of the physical phenomena associated with individual explosions, and of the expected or possible results of the use of many weapons in a nuclear war. Most emphasis is on the effects of so-called ``strategic exchanges.``

  4. Safe use of atomic (Nuclear) power (Nuclear Safety)

    NASA Astrophysics Data System (ADS)

    Sidorenko, V. A.

    2013-12-01

    The established concept of ensuring safety for nuclear power sources is presented; the influence of severe accidents on nuclear power development is considered, including the accident at a Japan NPP in 2011, as well as the role of state regulation of nuclear safety.

  5. EDITORIAL: Focus on Cold and Ultracold Molecules FOCUS ON COLD AND ULTRACOLD MOLECULES

    NASA Astrophysics Data System (ADS)

    Carr, Lincoln D.; Ye, Jun

    2009-05-01

    Cold and ultracold molecules are the next wave of ultracold physics, giving rise to an exciting array of scientific opportunities, including many body physics for novel quantum phase transitions, new states of matter, and quantum information processing. Precision tests of fundamental physical laws benefit from the existence of molecular internal structure with exquisite control. The study of novel collision and reaction dynamics will open a new chapter of quantum chemistry. Cold molecules bring together researchers from a variety of fields, including atomic, molecular, and optical physics, chemistry and chemical physics, quantum information science and quantum simulations, condensed matter physics, nuclear physics, and astrophysics, a truly remarkable synergy of scientific explorations. For the past decade there have been steady advances in direct cooling techniques, from buffer-gas cooling to cold molecular beams to electro- and magneto-molecular decelerators. These techniques have allowed a large variety of molecules to be cooled for pioneering studies. Recent amazing advances in experimental techniques combining the ultracold and the ultraprecise have furthermore brought molecules to the point of quantum degeneracy. These latter indirect cooling techniques magnetically associate atoms from a Bose-Einstein condensate and/or a quantum degenerate Fermi gas, transferring at 90% efficiency highly excited Fano-Feshbach molecules, which are on the order of 10 000 Bohr radii in size, to absolute ground state molecules just a few Bohr across. It was this latter advance, together with significant breakthroughs in internal state manipulations, which inspired us to coordinate this focus issue now, and is the reason why we say the next wave of ultracold physics has now arrived. Whether directly or indirectly cooled, heteronuclear polar molecules offer distinct new features in comparison to cold atoms, while sharing all of their advantages (purity, high coherence

  6. Nuclear explosive safety study process

    SciTech Connect

    1997-01-01

    Nuclear explosives by their design and intended use require collocation of high explosives and fissile material. The design agencies are responsible for designing safety into the nuclear explosive and processes involving the nuclear explosive. The methodology for ensuring safety consists of independent review processes that include the national laboratories, Operations Offices, Headquarters, and responsible Area Offices and operating contractors with expertise in nuclear explosive safety. A NES Study is an evaluation of the adequacy of positive measures to minimize the possibility of an inadvertent or deliberate unauthorized nuclear detonation, high explosive detonation or deflagration, fire, or fissile material dispersal from the pit. The Nuclear Explosive Safety Study Group (NESSG) evaluates nuclear explosive operations against the Nuclear Explosive Safety Standards specified in DOE O 452.2 using systematic evaluation techniques. These Safety Standards must be satisfied for nuclear explosive operations.

  7. Visualization of large elongated DNA molecules.

    PubMed

    Lee, Jinyong; Kim, Yongkyun; Lee, Seonghyun; Jo, Kyubong

    2015-09-01

    Long and linear DNA molecules are the mainstream single-molecule analytes for a variety of biochemical analysis within microfluidic devices, including functionalized surfaces and nanostructures. However, for biochemical analysis, large DNA molecules have to be unraveled, elongated, and visualized to obtain biochemical and genomic information. To date, elongated DNA molecules have been exploited in the development of a number of genome analysis systems as well as for the study of polymer physics due to the advantage of direct visualization of single DNA molecule. Moreover, each single DNA molecule provides individual information, which makes it useful for stochastic event analysis. Therefore, numerous studies of enzymatic random motions have been performed on a large elongated DNA molecule. In this review, we introduce mechanisms to elongate DNA molecules using microfluidics and nanostructures in the beginning. Secondly, we discuss how elongated DNA molecules have been utilized to obtain biochemical and genomic information by direct visualization of DNA molecules. Finally, we reviewed the approaches used to study the interaction of proteins and large DNA molecules. Although DNA-protein interactions have been investigated for many decades, it is noticeable that there have been significant achievements for the last five years. Therefore, we focus mainly on recent developments for monitoring enzymatic activity on large elongated DNA molecules.

  8. Nuclear Fabrication Consortium

    SciTech Connect

    Levesque, Stephen

    2013-04-05

    This report summarizes the activities undertaken by EWI while under contract from the Department of Energy (DOE) Office of Nuclear Energy (NE) for the management and operation of the Nuclear Fabrication Consortium (NFC). The NFC was established by EWI to independently develop, evaluate, and deploy fabrication approaches and data that support the re-establishment of the U.S. nuclear industry: ensuring that the supply chain will be competitive on a global stage, enabling more cost-effective and reliable nuclear power in a carbon constrained environment. The NFC provided a forum for member original equipment manufactures (OEM), fabricators, manufacturers, and materials suppliers to effectively engage with each other and rebuild the capacity of this supply chain by : Identifying and removing impediments to the implementation of new construction and fabrication techniques and approaches for nuclear equipment, including system components and nuclear plants. Providing and facilitating detailed scientific-based studies on new approaches and technologies that will have positive impacts on the cost of building of nuclear plants. Analyzing and disseminating information about future nuclear fabrication technologies and how they could impact the North American and the International Nuclear Marketplace. Facilitating dialog and initiate alignment among fabricators, owners, trade associations, and government agencies. Supporting industry in helping to create a larger qualified nuclear supplier network. Acting as an unbiased technology resource to evaluate, develop, and demonstrate new manufacturing technologies. Creating welder and inspector training programs to help enable the necessary workforce for the upcoming construction work. Serving as a focal point for technology, policy, and politically interested parties to share ideas and concepts associated with fabrication across the nuclear industry. The report the objectives and summaries of the Nuclear Fabrication Consortium

  9. NMR study of small molecule adsorption in MOF-74-Mg

    NASA Astrophysics Data System (ADS)

    Lopez, M. G.; Canepa, Pieremanuele; Thonhauser, T.

    2013-04-01

    We calculate the carbon nuclear magnetic resonance (NMR) shielding for CO2 and the hydrogen shieldings for both H2 and H2O inside the metal organic framework MOF-74-Mg. Our ab initio calculations are at the density functional theory level using the van der Waals including density functional vdW-DF. The shieldings are obtained while placing the small molecules throughout the structure, including the calculated adsorption site for various loading scenarios. We then explore relationships between loading, rotational and positional characteristics, and the NMR shieldings for each adsorbate. Our NMR calculations show a change in the shielding depending on adsorbate, position, and loading in a range that is experimentally observable. We further provide a simple model for the energy and the NMR shieldings throughout the cavity of the MOF. By providing this mapping of shielding to position and loading for these adsorbates, we argue that NMR probes could be used to provide additional information about the position at which these small molecules bind within the MOF, as well as the loading of the adsorbed molecule.

  10. NMR study of small molecule adsorption in MOF-74-Mg.

    PubMed

    Lopez, M G; Canepa, Pieremanuele; Thonhauser, T

    2013-04-21

    We calculate the carbon nuclear magnetic resonance (NMR) shielding for CO2 and the hydrogen shieldings for both H2 and H2O inside the metal organic framework MOF-74-Mg. Our ab initio calculations are at the density functional theory level using the van der Waals including density functional vdW-DF. The shieldings are obtained while placing the small molecules throughout the structure, including the calculated adsorption site for various loading scenarios. We then explore relationships between loading, rotational and positional characteristics, and the NMR shieldings for each adsorbate. Our NMR calculations show a change in the shielding depending on adsorbate, position, and loading in a range that is experimentally observable. We further provide a simple model for the energy and the NMR shieldings throughout the cavity of the MOF. By providing this mapping of shielding to position and loading for these adsorbates, we argue that NMR probes could be used to provide additional information about the position at which these small molecules bind within the MOF, as well as the loading of the adsorbed molecule.

  11. Profiling of Short RNAs Using Helicos Single-Molecule Sequencing

    PubMed Central

    Kapranov, Philipp; Ozsolak, Fatih; Milos, Patrice M.

    2012-01-01

    The importance of short (<200 nt) RNAs in cell biogenesis has been well documented. These short RNAs include crucial classes of molecules such as transfer RNAs, small nuclear RNA, microRNAs, and many others (reviewed in Storz et al., Annu Rev Biochem 74:199–217, 2005; Ghildiyal and Zamore, Nat Rev Genet 10:94–108, 2009). Furthermore, the realm of functional RNAs that fall within this size range is growing to include less well-characterized RNAs such as short RNAs found at the promoters and 3′ termini of genes (Affymetrix ENCODE Transcriptome Project et al., Nature 457:1028–1032, 2009; Davis and Ares, Proc Natl Acad Sci USA 103:3262–3267, 2006; Kapranov et al., Science 316:1484–1488, 2007; Taft et al., Nat Genet 41:572–578, 2009; Kapranov et al., Nature 466:642–646, 2010), short RNAs involved in paramutation (Rassoulzadegan et al., Nature 441:469–474, 2006), and others (reviewed in Kawaji and Hayashizaki, PLoS Genet 4:e22, 2008). Discovery and accurate quantification of these RNA molecules, less than 200 bases in size, is thus an important and also challenging aspect of understanding the full repertoire of cellular and extracellular RNAs. Here, we describe the strategies and procedures we developed to profile short RNA species using single-molecule sequencing (SMS) and the advantages SMS offers. PMID:22144202

  12. Nuclear Pasta

    NASA Astrophysics Data System (ADS)

    da Silva Schneider, Andre; Horowitz, Charles; Berry, Don; Briggs, Christian

    2014-03-01

    For decades it has been theorized that just below nuclear saturation density matter undergoes a series of phase transitions. These phases, which are expected to exist in core-collapse supernovae and neutron stars, involve a range of exotic nuclear shapes collectively known as nuclear pasta. Recently, Jose Pons and collaborators suggested that ``the maximum period of isolated X-ray pulsars may be the first observational evidence for an amorphous inner crust, ..., possibly owing to the existence of a nuclear pasta phase.'' In this talk we present results of semi-classical molecular dynamics simulations of nuclear pasta and discuss how each phase might contribute to neutron star crust properties.

  13. Model Action Plan for Nuclear Forensics and Nuclear Attribution

    SciTech Connect

    Dudder, G B; Niemeyer, S; Smith, D K; Kristo, M J

    2004-03-01

    Nuclear forensics and nuclear attribution have become increasingly important tools in the fight against illegal trafficking in nuclear and radiological materials. This technical report documents the field of nuclear forensics and nuclear attribution in a comprehensive manner, summarizing tools and procedures that have heretofore been described independently in the scientific literature. This report also provides national policy-makers, decision-makers, and technical managers with guidance for responding to incidents involving the interdiction of nuclear and radiological materials. However, due to the significant capital costs of the equipment and the specialized expertise of the personnel, work in the field of nuclear forensics has been restricted so far to a handful of national and international laboratories. In fact, there are a limited number of specialists who have experience working with interdicted nuclear materials and affiliated evidence. Most of the laboratories that have the requisite equipment, personnel, and experience to perform nuclear forensic analysis are participants in the Nuclear Smuggling International Technical Working Group or ITWG (see Section 1.8). Consequently, there is a need to disseminate information on an appropriate response to incidents of nuclear smuggling, including a comprehensive approach to gathering evidence that meets appropriate legal standards and to developing insights into the source and routes of nuclear and radiological contraband. Appendix A presents a ''Menu of Options'' for other Member States to request assistance from the ITWG Nuclear Forensics Laboratories (INFL) on nuclear forensic cases.

  14. Crystal structure of 5-amino-5'-chloro-6-(4-chloro-benzo-yl)-8-nitro-2,3-di-hydro-1H-spiro-[imidazo[1,2-a]pyridine-7,3'-indolin]-2'-one including an unknown solvent mol-ecule.

    PubMed

    Nagalakshmi, R A; Suresh, J; Sivakumar, S; Kumar, R Ranjith; Lakshman, P L Nilantha

    2014-09-01

    The asymmetric unit of the title compound, C21H15Cl2N5O4, contains two independent mol-ecules (A and B) having similar conformations. The amine (NH2) group forms an intra-molecular hydrogen bond with the benzoyl group, giving an S(6) ring motif in both mol-ecules. The central six-membered rings adopt sofa conformations and the imidazole rings are planar (r.m.s deviations = 0.0150 and 0.0166 Å). The pyridine and imidazole rings are inclined to one another by 3.54 (1) and 3.03 (1)° in mol-ecules A and B, respectively. In the crystal, mol-ecules are linked by N-H⋯O hydrogen bonds, forming chains along the a axis which enclose R 2 (2)(16) ring motifs. The rings are linked by weak N-H⋯O and C-H⋯O hydrogen bonds and C-H⋯π inter-actions forming sheets lying parallel to (001). A region of disordered electron density, most probably disordered solvent mol-ecules, occupying voids of ca 753 Å(3) for an electron count of 260, was treated using the SQUEEZE routine in PLATON [Spek (2009 ▶). Acta Cryst. D65, 148-155]. Their formula mass and unit-cell characteristics were not taken into account during refinement.

  15. Nuclear orientation and nuclear structure

    SciTech Connect

    Krane, K.S.

    1988-01-01

    The present generation of on-line nuclear orientation facilities promises to revolutionize the gathering of nuclear structure information, especially for the hitherto poorly known and understood nuclei far from stability. Following a brief review of the technological developments that have facilitated these experiments, the nuclear spectroscopic information that can be obtained is summarized. Applications to understanding nuclear structure are reviewed, and challenges for future studies are discussed. 14 refs., 4 figs., 3 tabs.

  16. Nuclear Technology: Making Informed Decisions.

    ERIC Educational Resources Information Center

    Altshuler, Kenneth

    1989-01-01

    Discusses a unit on nuclear technology which is taught in a physics class. Explains the unit design, implementation process, demonstrations used, and topics of discussion that include light and optics, naturally and artificially produced sources of radioactivity, nuclear equations, isotopes and half-lives, and power-generating nuclear reactors.…

  17. Nuclear Technology: Making Informed Decisions.

    ERIC Educational Resources Information Center

    Altshuler, Kenneth

    1989-01-01

    Discusses a unit on nuclear technology which is taught in a physics class. Explains the unit design, implementation process, demonstrations used, and topics of discussion that include light and optics, naturally and artificially produced sources of radioactivity, nuclear equations, isotopes and half-lives, and power-generating nuclear reactors.…

  18. Molecules in the Spotlight

    SciTech Connect

    Cryan, James

    2010-01-26

    SLAC has just unveiled the world's first X-ray laser, the LCLS. This machine produces pulses of X-rays that are ten billion times brighter than those from conventional sources. One of the goals of this machine is to make movies of chemical reactions, including reactions necessary for life and reactions that might power new energy technologies. This public lecture will show the first results from the LCLS. As a first target, we have chosen nitrogen gas, the main component of the air we breathe. Using the unprecedented power of the LCLS X-rays as a blasting torch, we have created new forms of this molecule and with unique electronic arrangements. Please share with us the first insights from this new technology.

  19. Nuclear reactor

    DOEpatents

    Wade, Elman E.

    1979-01-01

    A nuclear reactor including two rotatable plugs and a positive top core holddown structure. The top core holddown structure is divided into two parts: a small core cover, and a large core cover. The small core cover, and the upper internals associated therewith, are attached to the small rotating plug, and the large core cover, with its associated upper internals, is attached to the large rotating plug. By so splitting the core holddown structures, under-the-plug refueling is accomplished without the necessity of enlarging the reactor pressure vessel to provide a storage space for the core holddown structure during refueling. Additionally, the small and large rotating plugs, and their associated core covers, are arranged such that the separation of the two core covers to permit rotation is accomplished without the installation of complex lifting mechanisms.

  20. Nuclear networking.

    PubMed

    Xie, Wei; Burke, Brian

    2017-07-04

    Nuclear lamins are intermediate filament proteins that represent important structural components of metazoan nuclear envelopes (NEs). By combining proteomics and superresolution microscopy, we recently reported that both A- and B-type nuclear lamins form spatially distinct filament networks at the nuclear periphery of mouse fibroblasts. In particular, A-type lamins exhibit differential association with nuclear pore complexes (NPCs). Our studies reveal that the nuclear lamina network in mammalian somatic cells is less ordered and more complex than that of amphibian oocytes, the only other system in which the lamina has been visualized at high resolution. In addition, the NPC component Tpr likely links NPCs to the A-type lamin network, an association that appears to be regulated by C-terminal modification of various A-type lamin isoforms. Many questions remain, however, concerning the structure and assembly of lamin filaments, as well as with their mode of association with other nuclear components such as peripheral chromatin.

  1. Nuclear energy law after Chernobyl

    SciTech Connect

    Cameron, P.; Harcher, L.

    1988-01-01

    This work examines the legal issues surrounding the possibility of accidents at nuclear installations in Europe. Contents include: Regulations and control by international organizations in the context of a nuclear accident; The role of Euratom; Border installations: the interaction of administrative, European community and public international law; and Border installations: the experience of Wackersdorf. Concepts of nuclear liability and the liability of suppliers to nuclear power plants are discussed.

  2. Nuclear structure and weak probes

    NASA Astrophysics Data System (ADS)

    Horoi, Mihai

    2017-06-01

    Weak interaction in nuclei represents a well-known venue for testing many of the fundamental symmetries of the Standard Model. Analysis of these processes requires nuclear structure information, including nuclear data, and some theoretical approaches to describe it. Here we make an introduction into basic nuclear structure concepts, using the existing nuclear data and some simple mean-field and shell model approaches. Some applications to beta decays and double beta decays are presented.

  3. Security culture for nuclear facilities

    NASA Astrophysics Data System (ADS)

    Gupta, Deeksha; Bajramovic, Edita

    2017-01-01

    Natural radioactive elements are part of our environment and radioactivity is a natural phenomenon. There are numerous beneficial applications of radioactive elements (radioisotopes) and radiation, starting from power generation to usages in medical, industrial and agriculture applications. But the risk of radiation exposure is always attached to operational workers, the public and the environment. Hence, this risk has to be assessed and controlled. The main goal of safety and security measures is to protect human life, health, and the environment. Currently, nuclear security considerations became essential along with nuclear safety as nuclear facilities are facing rapidly increase in cybersecurity risks. Therefore, prevention and adequate protection of nuclear facilities from cyberattacks is the major task. Historically, nuclear safety is well defined by IAEA guidelines while nuclear security is just gradually being addressed by some new guidance, especially the IAEA Nuclear Security Series (NSS), IEC 62645 and some national regulations. At the overall level, IAEA NSS 7 describes nuclear security as deterrence and detection of, and response to, theft, sabotage, unauthorized access, illegal transfer or other malicious acts involving nuclear, other radioactive substances and their associated facilities. Nuclear security should be included throughout nuclear facilities. Proper implementation of a nuclear security culture leads to staff vigilance and a high level of security posture. Nuclear security also depends on policy makers, regulators, managers, individual employees and members of public. Therefore, proper education and security awareness are essential in keeping nuclear facilities safe and secure.

  4. Advanced Nuclear Fuel Cycle Options

    SciTech Connect

    Roald Wigeland; Temitope Taiwo; Michael Todosow; William Halsey; Jess Gehin

    2010-06-01

    A systematic evaluation has been conducted of the potential for advanced nuclear fuel cycle strategies and options to address the issues ascribed to the use of nuclear power. Issues included nuclear waste management, proliferation risk, safety, security, economics and affordability, and sustainability. The two basic strategies, once-through and recycle, and the range of possibilities within each strategy, are considered for all aspects of the fuel cycle including options for nuclear material irradiation, separations if needed, and disposal. Options range from incremental changes to today’s implementation to revolutionary concepts that would require the development of advanced nuclear technologies.

  5. Pump apparatus including deconsolidator

    DOEpatents

    Sonwane, Chandrashekhar; Saunders, Timothy; Fitzsimmons, Mark Andrew

    2014-10-07

    A pump apparatus includes a particulate pump that defines a passage that extends from an inlet to an outlet. A duct is in flow communication with the outlet. The duct includes a deconsolidator configured to fragment particle agglomerates received from the passage.

  6. Just war theory in the nuclear age

    SciTech Connect

    Jones, J.D.; Griesbach, M.F.

    1985-01-01

    This book presents papers on nuclear deterrence. Topics considered include the morality of war, the normative alternatives to war, national defense in the nuclear age, the environment of nuclear deterrence (empirical factors and moral judgments), morality and nuclear weaponry, the morality of nuclear deterrence and national defense in a changing strategic environment, alternatives to nuclear deterrence, and strengthening broadcasting capabilities into the USSR (e.g., Radio Liberty and Voice of America).

  7. Nuclear Futures Analysis and Scenario Building

    SciTech Connect

    Arthur, E.D.; Beller, D.; Canavan, G.H.; Krakowski, R.A.; Peterson, P.; Wagner, R.L.

    1999-07-09

    This LDRD project created and used advanced analysis capabilities to postulate scenarios and identify issues, externalities, and technologies associated with future ''things nuclear''. ''Things nuclear'' include areas pertaining to nuclear weapons, nuclear materials, and nuclear energy, examined in the context of future domestic and international environments. Analysis tools development included adaptation and expansion of energy, environmental, and economics (E3) models to incorporate a robust description of the nuclear fuel cycle (both current and future technology pathways), creation of a beginning proliferation risk model (coupled to the (E3) model), and extension of traditional first strike stability models to conditions expected to exist in the future (smaller force sizes, multipolar engagement environments, inclusion of actual and latent nuclear weapons (capability)). Accomplishments include scenario development for regional and global nuclear energy, the creation of a beginning nuclear architecture designed to improve the proliferation resistance and environmental performance of the nuclear fuel cycle, and numerous results for future nuclear weapons scenarios.

  8. Formation of Ultracold Molecules

    SciTech Connect

    Cote, Robin

    2016-01-28

    Advances in our ability to slow down and cool atoms and molecules to ultracold temperatures have paved the way to a revolution in basic research on molecules. Ultracold molecules are sensitive of very weak interactions, even when separated by large distances, which allow studies of the effect of those interactions on the behavior of molecules. In this program, we have explored ways to form ultracold molecules starting from pairs of atoms that have already reached the ultracold regime. We devised methods that enhance the efficiency of ultracold molecule production, for example by tuning external magnetic fields and using appropriate laser excitations. We also investigates the properties of those ultracold molecules, especially their de-excitation into stable molecules. We studied the possibility of creating new classes of ultra-long range molecules, named macrodimers, thousand times more extended than regular molecules. Again, such objects are possible because ultra low temperatures prevent their breakup by collision. Finally, we carried out calculations on how chemical reactions are affected and modified at ultracold temperatures. Normally, reactions become less effective as the temperature decreases, but at ultracold temperatures, they can become very effective. We studied this counter-intuitive behavior for benchmark chemical reactions involving molecular hydrogen.

  9. The Molecule Cloud - compact visualization of large collections of molecules.

    PubMed

    Ertl, Peter; Rohde, Bernhard

    2012-07-06

    Analysis and visualization of large collections of molecules is one of the most frequent challenges cheminformatics experts in pharmaceutical industry are facing. Various sophisticated methods are available to perform this task, including clustering, dimensionality reduction or scaffold frequency analysis. In any case, however, viewing and analyzing large tables with molecular structures is necessary. We present a new visualization technique, providing basic information about the composition of molecular data sets at a single glance. A method is presented here allowing visual representation of the most common structural features of chemical databases in a form of a cloud diagram. The frequency of molecules containing particular substructure is indicated by the size of respective structural image. The method is useful to quickly perceive the most prominent structural features present in the data set. This approach was inspired by popular word cloud diagrams that are used to visualize textual information in a compact form. Therefore we call this approach "Molecule Cloud". The method also supports visualization of additional information, for example biological activity of molecules containing this scaffold or the protein target class typical for particular scaffolds, by color coding. Detailed description of the algorithm is provided, allowing easy implementation of the method by any cheminformatics toolkit. The layout algorithm is available as open source Java code. Visualization of large molecular data sets using the Molecule Cloud approach allows scientists to get information about the composition of molecular databases and their most frequent structural features easily. The method may be used in the areas where analysis of large molecular collections is needed, for example processing of high throughput screening results, virtual screening or compound purchasing. Several example visualizations of large data sets, including PubChem, ChEMBL and ZINC databases using

  10. Electron attachment to the SF{sub 6} molecule

    SciTech Connect

    Smirnov, B. M. Kosarim, A. V.

    2015-09-15

    Various models for transition between electron and nuclear subsystems are compared in the case of electron attachment to the SF{sub 6} molecule. Experimental data, including the cross section of electron attachment to this molecule as a function of the electron energy and vibrational temperature, the rate constants of this process in swarm experiments, and the rates of the chemionization process involving Rydberg atoms and the SF{sub 6} molecule, are collected and treated. Based on the data and on the resonant character of electron capture into an autodetachment ion state in accordance with the Breit–Wigner formula, we find that intersection of the molecule and negative ion electron terms proceeds above the potential well bottom of the molecule with the barrier height 0.05–0.1 eV, and the transition between these electron terms has both the tunnel and abovebarrier character. The limit of small electron energies e for the electron attachment cross section at room vibrational temperature takes place at ε ≪ 2 meV, while in the range 2 meV ≪ ε ≪ 80 meV, the cross section is inversely proportional to ε. In considering the attachment process as a result of the interaction between the electron and vibrational degrees of freedom, we find the coupling factor f between them to be f = aT at low vibrational temperatures T with a ≈ 3 × 10{sup −4} K{sup −1}. The coupling factor is independent of the temperature at T > 400 K.

  11. Optical modulator including grapene

    DOEpatents

    Liu, Ming; Yin, Xiaobo; Zhang, Xiang

    2016-06-07

    The present invention provides for a one or more layer graphene optical modulator. In a first exemplary embodiment the optical modulator includes an optical waveguide, a nanoscale oxide spacer adjacent to a working region of the waveguide, and a monolayer graphene sheet adjacent to the spacer. In a second exemplary embodiment, the optical modulator includes at least one pair of active media, where the pair includes an oxide spacer, a first monolayer graphene sheet adjacent to a first side of the spacer, and a second monolayer graphene sheet adjacent to a second side of the spacer, and at least one optical waveguide adjacent to the pair.

  12. A toy model for a diatomic molecule

    NASA Astrophysics Data System (ADS)

    Hecker Denschlag, Johannes

    2016-08-01

    We introduce a toy model for a diatomic molecule which is based on coupling electronic and nuclear spins to a rigid rotor. Despite its simplicity, the model can be used scientifically to analyze and understand complex molecular hyperfine spectra. In addition, the model has educational value as a number of fundamental symmetries and conservation laws of the molecule can be studied. Because of its simple structure, the model can be readily implemented as a computer program with comparatively short computing times on the order of a few seconds.

  13. Metabonomics by proton nuclear magnetic resonance in human pleural effusions: A route to discriminate between benign and malignant pleural effusions and to target small molecules as potential cancer biomarkers.

    PubMed

    Zennaro, Lucio; Vanzani, Paola; Nicolè, Lorenzo; Cappellesso, Rocco; Fassina, Ambrogio

    2017-05-01

    Cytopathology is a noninvasive and cost-effective method for detecting cancer cells in pleural effusions (PEs), although in many cases, the diagnostic performance is hindered by the paucity of significant cells or the lack of clear morphological criteria. This study presents the results of an omics approach to improving the diagnostic performance of PE cytology. Metabolic profiling with proton nuclear magnetic resonance ((1) H-NMR) was performed for 92 PEs (44 malignant cases of 8 different cancers and 48 benign cases of 7 nonneoplastic conditions). Light's criteria were used to further classify PEs as transudates or exudates, and (1) H-NMR spectroscopy was used to differentiate malignant pleural effusions (mPEs) from benign pleural effusions (bPEs). (1) H-NMR metabolic analysis showed clearly different spectra for mPEs and bPEs in the regions of the signals due to lipids, branched amino acids, and lactate, which were increased in mPEs. Transudates and exudates in bPEs were differentiated as well on the basis of the (1) H-NMR signals from lipids and lipoproteins, which were increased in exudates. Subject to validation in further larger studies, (1) H-NMR metabonomics could be an effective and reliable ancillary tool for PE investigations and diagnoses. Cancer Cytopathol 2017;125:341-348. © 2017 American Cancer Society. © 2017 American Cancer Society.

  14. Electrorheological crystallization of proteins and other molecules

    DOEpatents

    Craig, G.D.; Rupp, B.

    1996-06-11

    An electrorheological crystalline mass of a molecule is formed by dispersing the molecule in a dispersion fluid and subjecting the molecule dispersion to a uniform electrical field for a period of time during which time an electrorheological crystalline mass is formed. Molecules that may be used to form an electrorheological crystalline mass include any organic or inorganic molecule which has a permanent dipole and/or which is capable of becoming an induced dipole in the presence of an electric field. The molecules used to form the electrorheological crystalline mass are preferably macromolecules, such as biomolecules, such as proteins, nucleic acids, carbohydrates, lipoproteins and viruses. Molecules are crystallized by a method in which an electric field is maintained for a period of time after the electrorheological crystalline mass has formed during which time at least some of the molecules making up the electrorheological crystalline mass form a crystal lattice. The three dimensional structure of a molecule is determined by a method in which an electrorheological crystalline mass of the molecule is formed, an X-ray diffraction pattern of the electrorheological crystalline mass is obtained and the three dimensional structure of the molecule is calculated from the X-ray diffraction pattern. 4 figs.

  15. Electrorheological crystallization of proteins and other molecules

    DOEpatents

    Craig, George D.; Rupp, Bernhard

    1996-01-01

    An electrorheological crystalline mass of a molecule is formed by dispersing the molecule in a dispersion fluid and subjecting the molecule dispersion to a uniform electrical field for a period of time during which time an electrorheological crystalline mass is formed. Molecules that may be used to form an electrorheological crystalline mass include any organic or inorganic molecule which has a permanent dipole and/or which is capable of becoming an induced dipole in the presence of an electric field. The molecules used to form the electrorheological crystalline mass are preferably macromolecules, such as biomolecules, such as proteins, nucleic acids, carbohydrates, lipoproteins and viruses. Molecules are crystallized by a method in which an electric field is maintained for a period of time after the electrorheological crystalline mass has formed during which time at least some of the molecules making up the electrorheological crystalline mass form a crystal lattice. The three dimensional structure of a molecule is determined by a method in which an electrorheological crystalline mass of the molecule is formed, an x-ray diffraction pattern of the electrorheological crystalline mass is obtained and the three dimensional structure of the molecule is calculated from the x-ray diffraction pattern.

  16. Nuclear Halos

    SciTech Connect

    Vogt, Erich

    2010-07-27

    We show that extreme nuclear halos are caused only by pairs of s-wave neutrons (or single s-wave neutrons) and that such states occur much more frequently in the periodic table than previously believed. Besides lingering long near zero neutron separation energy such extreme halos have very remarkable properties: they can contribute significantly to the nuclear density at more than twice the normal nuclear radius and their spreading width can be very narrow. The properties of these states are primarily determined by the ''thickness'' of the nuclear surface in the mean-free nuclear potential and thus their importance increases greatly as we approach the neutron drip line. We discuss what such extreme halos are, where they occur, what their properties are and some of their impact on nuclear observations.

  17. Interstellar molecules and dense clouds.

    NASA Technical Reports Server (NTRS)

    Rank, D. M.; Townes, C. H.; Welch, W. J.

    1971-01-01

    Current knowledge of the interstellar medium is discussed on the basis of recent published studies. The subjects considered include optical identification of interstellar molecules, radio molecular lines, interstellar clouds, isotopic abundances, formation and disappearance of interstellar molecules, and interstellar probing techniques. Diagrams are plotted for the distribution of galactic sources exhibiting molecular lines, for hydrogen molecule, hydrogen atom and electron abundances due to ionization, for the densities, velocities and temperature of NH3 in the direction of Sagitarius B2, for the lower rotational energy levels of H2CO, and for temporal spectral variations in masing H2O clouds of the radio source W49. Future applications of the maser and of molecular microscopy in this field are visualized.

  18. Guidance molecules in lung cancer

    PubMed Central

    Nasarre, Patrick; Potiron, Vincent; Drabkin, Harry

    2010-01-01

    Guidance molecules were first described in the nervous system to control axon outgrowth direction. They are also widely expressed outside the nervous system where they control cell migration, tissue development and establishment of the vascular network. In addition, they are involved in cancer development, tumor angiogenesis and metastasis. This review is primarily focused on their functions in lung cancer and their involvement in lung development is also presented. Five guidance molecule families and their corresponding receptors are described, including the semaphorins/neuropilins/plexins, ephrins and Eph receptors, netrin/DCC/UNC5, Slit/Robo and Notch/Delta. In addition, the possibility to target these molecules as a therapeutic approach in cancer is discussed. PMID:20139699

  19. The status of molecules

    SciTech Connect

    Barnes, T. :

    1994-10-01

    This report summarizes the experimental and theoretical status of hadronic molecules, which are weakly-bound states of two or more hadrons. We begin with a brief history of the subject and discuss a few good candidates, and then abstract some signatures for molecules which may be of interest in the classification of possible molecule states. Next we argue that a more general understanding of 2 {yields} 2 hadron-hadron scattering amplitudes will be crucial for molecule searches, and discuss some of our recent work in this area. We conclude with a discussion of a few more recent molecule candidates (notably the f{sub o}(1710)) which are not well established as molecules but satisfy some of the expected signatures.

  20. UNcleProt (Universal Nuclear Protein database of barley): The first nuclear protein database that distinguishes proteins from different phases of the cell cycle.

    PubMed

    Blavet, Nicolas; Uřinovská, Jana; Jeřábková, Hana; Chamrád, Ivo; Vrána, Jan; Lenobel, René; Beinhauer, Jana; Šebela, Marek; Doležel, Jaroslav; Petrovská, Beáta

    2017-01-02

    Proteins are the most abundant component of the cell nucleus, where they perform a plethora of functions, including the assembly of long DNA molecules into condensed chromatin, DNA replication and repair, regulation of gene expression, synthesis of RNA molecules and their modification. Proteins are important components of nuclear bodies and are involved in the maintenance of the nuclear architecture, transport across the nuclear envelope and cell division. Given their importance, the current poor knowledge of plant nuclear proteins and their dynamics during the cell's life and division is striking. Several factors hamper the analysis of the plant nuclear proteome, but the most critical seems to be the contamination of nuclei by cytosolic material during their isolation. With the availability of an efficient protocol for the purification of plant nuclei, based on flow cytometric sorting, contamination by cytoplasmic remnants can be minimized. Moreover, flow cytometry allows the separation of nuclei in different stages of the cell cycle (G1, S, and G2). This strategy has led to the identification of large number of nuclear proteins from barley (Hordeum vulgare), thus triggering the creation of a dedicated database called UNcleProt, http://barley.gambrinus.ueb.cas.cz/ .

  1. UNcleProt (Universal Nuclear Protein database of barley): The first nuclear protein database that distinguishes proteins from different phases of the cell cycle

    PubMed Central

    Uřinovská, Jana; Jeřábková, Hana; Chamrád, Ivo; Lenobel, René; Beinhauer, Jana; Šebela, Marek

    2017-01-01

    ABSTRACT Proteins are the most abundant component of the cell nucleus, where they perform a plethora of functions, including the assembly of long DNA molecules into condensed chromatin, DNA replication and repair, regulation of gene expression, synthesis of RNA molecules and their modification. Proteins are important components of nuclear bodies and are involved in the maintenance of the nuclear architecture, transport across the nuclear envelope and cell division. Given their importance, the current poor knowledge of plant nuclear proteins and their dynamics during the cell's life and division is striking. Several factors hamper the analysis of the plant nuclear proteome, but the most critical seems to be the contamination of nuclei by cytosolic material during their isolation. With the availability of an efficient protocol for the purification of plant nuclei, based on flow cytometric sorting, contamination by cytoplasmic remnants can be minimized. Moreover, flow cytometry allows the separation of nuclei in different stages of the cell cycle (G1, S, and G2). This strategy has led to the identification of large number of nuclear proteins from barley (Hordeum vulgare), thus triggering the creation of a dedicated database called UNcleProt, http://barley.gambrinus.ueb.cas.cz/. PMID:27813701

  2. High energy nuclear structures

    SciTech Connect

    Boguta, J.; Kunz, J.

    1984-03-09

    In conventional nuclear physics the nucleus is described as a non-relativistic many-body system, which is governed by the Schroedinger equation. Nucleons interact in this framework via static two-body potentials, mesonic degrees of freedom are neglected. An alternative description of nuclear physics in terms of a relativistic field theory has been developed by Walecka. The model Lagrangian containing baryons, sigma-mesons and ..omega..-mesons was subsequently extended to include also ..pi..-mesons and rho-mesons. An essential feature of such a nuclear Lagrangian is its renormalizability. In addition to the description of known nuclear structure the field theoretical approach may reveal entirely new nuclear phenomena, based on the explicit treatment of mesonic degrees of freedom. The existence of such abnormal nuclear states was proposed by Lee and Wick employing the sigma-model Lagrangian. There the non-linearity of the meson field equations allows for soliton solutions in the presence of nucleons, in particular the sigma-field may exhibit a kink. Different types of soliton solutions occur in gauge theories with hidden symmetries. In the phenomenological Lagrangian the rho-meson is described by a non-abelian gauge field, that acquires its mass spontaneously due to the non-vanishing vacuum expectation value of a Higgs field. A general ansatz for soliton solutions of such a gauge theory was given by Dashen et al. A specific solution and its possible implications for nuclear physics like anomalous nuclear states were discussed by Boguta.

  3. Nuclear Fission

    NASA Astrophysics Data System (ADS)

    Denschlag, J. O.

    This chapter first gives a survey on the history of the discovery of nuclear fission. It briefly presents the liquid-drop and shell models and their application to the fission process. The most important quantities accessible to experimental determination such as mass yields, nuclear charge distribution, prompt neutron emission, kinetic energy distribution, ternary fragment yields, angular distributions, and properties of fission isomers are presented as well as the instrumentation and techniques used for their measurement. The contribution concentrates on the fundamental aspects of nuclear fission. The practical aspects of nuclear fission are discussed in http://dx.doi.org/10.1007/978-1-4419-0720-2_57 of Vol. 6.

  4. [Endothelial cell adhesion molecules].

    PubMed

    Ivanov, A N; Norkin, I A; Puchin'ian, D M; Shirokov, V Iu; Zhdanova, O Iu

    2014-01-01

    The review presents current data concerning the functional role of endothelial cell adhesion molecules belonging to different structural families: integrins, selectins, cadherins, and the immunoglobulin super-family. In this manuscript the regulatory mechanisms and factors of adhesion molecules expression and distribution on the surface of endothelial cells are discussed. The data presented reveal the importance of adhesion molecules in the regulation of structural and functional state of endothelial cells in normal conditions and in pathology. Particular attention is paid to the importance of these molecules in the processes of physiological and pathological angiogenesis, regulation of permeability of the endothelial barrier and cell transmigration.

  5. Answers to Questions: Nuclear Energy.

    ERIC Educational Resources Information Center

    Department of Energy, Washington, DC. Nuclear Energy Office.

    Electricity is an increasingly important part of our everyday lives. Its versatility allows one to heat, cool, and light homes; cook meals; watch television; listen to music; power computers; make medical diagnosis and treatment; explore the vastness of space; and study the tiniest molecules. Nuclear energy, second to coal, surpasses natural gas,…

  6. Psychoanalysis and the nuclear threat

    SciTech Connect

    Levine, H.B.; Jacobs, D.; Rubin, L.J.

    1988-01-01

    {ital Psychoanalysis and the Nuclear Threat} provides coverage of the dynamic and clinical considerations that follow from life in the nuclear age. Of special clinical interest are chapters dealing with the developmental consequences of the nuclear threat in childhood, adolescence, and adulthood, and those exploring the technical issues raised by the occurrence in analytic and psychotherapeutic hours of material related to the nuclear threat. Additional chapters bring a psychoanalytic perspective to bear on such issues as the need to have enemies, silence as the real crime, love, work, and survival in the nuclear age, the relationship of the nuclear threat to issues of mourning and melancholia, apocalyptic fantasies, the paranoid process, considerations of the possible impact of gender on the nuclear threat, and the application of psychoanalytic thinking to nuclear arms strategy. Finally, the volume includes the first case report in the English language---albeit a brief psychotherapy---involving the treatment of a Hiroshima survivor.

  7. International Nuclear Safeguards at Sandia

    SciTech Connect

    Sternat, Matthew R.

    2015-02-01

    As global nuclear energy expands, assuring peaceful uses of nuclear technology becomes increasingly important. In addition to complying with international nuclear safeguards, a responsible nuclear energy program promotes a corresponding safeguards culture. Establishment of transparent peaceful uses of nuclear technologies starts with cooperative international engagements and safeguards systems. Developing states investing in nuclear energy must assure the international community of their longterm commitment to safeguards, safety, and security (3S) of nuclear materials and technologies. Cultivating a safeguards culture starts in the initial phases of infrastructure planning and must be integrated into the process of developing a responsible nuclear energy program. Sandia National Laboratories supports the implementation of safeguards culture through a variety of activities, including infrastructure development.

  8. Omega 3 (n-3) fatty acids down-regulate nuclear factor-kappa B (NF-κB) gene and blood cell adhesion molecule expression in patients with homozygous sickle cell disease.

    PubMed

    Daak, Ahmed A; Elderdery, Abozer Y; Elbashir, Leana M; Mariniello, Katia; Mills, Jeremy; Scarlett, Garry; Elbashir, Mustafa I; Ghebremeskel, Kebreab

    2015-06-01

    Chronic inflammation and reduced blood levels of omega-3 fatty acids (n-3) are known characteristics of sickle cell disease (SCD).The anti-inflammatory properties of n-3 fatty acids are well recognized. Omega-3 treated (n = 24), hydroxyurea (HU) treated (n = 18), and n-3 untreated (n=21) homozygous SCD patients (HbSS) and healthy (HbAA) controls (n = 25) matched for age (5-16 years), gender and socioeconomic status were studied. According to age (5-10) or (11-16) years, two or three capsules containing 277.8 mg docosahexaenoic (DHA) and 39.0mg eicosapentaenoic (EPA) or high oleic acid placebo (41%) were assigned to n-3 treated and n-3 untreated groups, respectively. Hydroxyurea treated group was on dosage more than 20 mg/kg/day. The effect of supplementation on systemic and blood cell markers of inflammation was investigated. The n-3 treated group had higher levels of DHA and EPA (p < 0.001) and lower white blood cell count and monocyte integrin (p < 0.05) compared with the n-3 untreated. No difference was detected between the two groups regarding C-reactive protein, granulocytes integrin and selectin, plasma tumour necrosis factor-α and interleukin-10. The n-3 treated group had lowered nuclear factor-kappa B (NF-κB) gene expression compared to n-3 untreated and HU treated groups (p < 0.05). This study provides evidence that supplementation with n-3 fatty acids may ameliorate inflammation and blood cell adhesion in patients with SCD.

  9. Special Issue: "Molecules against Alzheimer".

    PubMed

    Decker, Michael; Muñoz-Torrero, Diego

    2016-12-16

    This Special Issue, entitled "Molecules against Alzheimer", gathers a number of original articles, short communications, and review articles on recent research efforts toward the development of novel drug candidates, diagnostic agents and therapeutic approaches for Alzheimer's disease (AD), the most prevalent neurodegenerative disorder and a leading cause of death worldwide. This Special Issue contains many interesting examples describing the design, synthesis, and pharmacological profiling of novel compounds that hit one or several key biological targets, such as cholinesterases, β-amyloid formation or aggregation, monoamine oxidase B, oxidative stress, biometal dyshomeostasis, mitochondrial dysfunction, serotonin and/or melatonin systems, the Wnt/β-catenin pathway, sigma receptors, nicotinamide phosphoribosyltransferase, or nuclear erythroid 2-related factor. The development of novel AD diagnostic agents based on tau protein imaging and the use of lithium or intranasal insulin for the prevention or the symptomatic treatment of AD is also covered in some articles of the Special Issue.

  10. Evaluated Nuclear Data

    SciTech Connect

    Oblozinsky, P.; Oblozinsky,P.; Herman,M.; Mughabghab,S.F.

    2010-10-01

    This chapter describes the current status of evaluated nuclear data for nuclear technology applications. We start with evaluation procedures for neutron-induced reactions focusing on incident energies from the thermal energy up to 20 MeV, though higher energies are also mentioned. This is followed by examining the status of evaluated neutron data for actinides that play dominant role in most of the applications, followed by coolants/moderators, structural materials and fission products. We then discuss neutron covariance data that characterize uncertainties and correlations. We explain how modern nuclear evaluated data libraries are validated against an extensive set of integral benchmark experiments. Afterwards, we briefly examine other data of importance for nuclear technology, including fission yields, thermal neutron scattering and decay data. A description of three major evaluated nuclear data libraries is provided, including the latest version of the US library ENDF/B-VII.0, European JEFF-3.1 and Japanese JENDL-3.3. A brief introduction is made to current web retrieval systems that allow easy access to a vast amount of up-to-date evaluated nuclear data for nuclear technology applications.

  11. Ethics and nuclear arms: European and American perspectives

    SciTech Connect

    English, R.

    1985-01-01

    This book presents papers on the ethical and moral aspects of nuclear weapons. Topics considered include the development of a nuclear policy, war and peace in the nuclear age, the viewpoint of the German churches, the US Catholic bishops and nuclear arms, nuclear pacifism, NATO and ''first use,'' and Christian morality with regard to nuclear arms.

  12. Resource Letter FNP-1: Frontiers of nuclear physics

    NASA Astrophysics Data System (ADS)

    Bertsch, G. F.

    2004-08-01

    This Resource Letter provides a bibliography of the current research activities in nuclear physics and also a guide for finding useful nuclear data. The major areas included are nuclear structure and reactions, symmetry tests, nuclear astrophysics, nuclear theory, high-density matter, and nuclear instrumentation.

  13. Transactions of the fifth symposium on space nuclear power systems

    SciTech Connect

    El-Genk, M.S.; Hoover, M.D.

    1988-01-01

    This paper contains the presented papers at the fourth symposium on space nuclear power systems. Topics of these paper include: space nuclear missions and applications, reactors and shielding, nuclear electric and nuclear propulsion, high-temperature materials, instrumentation and control, energy conversion and storage, space nuclear fuels, thermal management, nuclear safety, simulation and modeling, and multimegawatt system concepts. (LSP)

  14. Transactions of the fourth symposium on space nuclear power systems

    SciTech Connect

    El-Genk, M.S.; Hoover, M.D.

    1987-01-01

    This paper contains the presented papers at the fourth symposium on space nuclear power systems. Topics of these papers include: space nuclear missions and applications, reactors and shielding, nuclear electric and nuclear propulsion, refractory alloys and high-temperature materials, instrumentation and control, energy conversion and storage, space nuclear fuels, thermal management, nuclear safety, simulation and modeling, and multimegawatt system concepts. (LSP)

  15. Nuclear Regulatory Commission issuances

    SciTech Connect

    1996-03-01

    This document is the March 1996 listing of NRC issuances. Included are: (1) NRC orders granting Cleveland Electric Illuminating Company`s petition for review of the ASLB order LBP-95-17, (2) NRC orders relating to the potential disqualification of two commissioners in the matter of the decommissioning of Yankee Nuclear Power Station, (3) ASLB orders pertaining to the Oncology Services Corporation, (4) ASLB orders pertaining to the Radiation Oncology Center, (5) ASLB orders pertaining to the Yankee Nuclear Power Station, and (6) Director`s decision pertaining to the Yankee Nuclear Power Station.

  16. Nuclear Medicine Annual, 1989

    SciTech Connect

    Freeman, L.M.; Weissmann, H.S.

    1989-01-01

    Among the highlights of Nuclear Medicine Annual, 1989 are a status report on the thyroid scan in clinical practice, a review of functional and structural brain imaging in dementia, an update on radionuclide renal imaging in children, and an article outlining a quality assurance program for SPECT instrumentation. Also included are discussions on current concepts in osseous sports and stress injury scintigraphy and on correlative magnetic resonance and radionuclide imaging of bone. Other contributors assess the role of nuclear medicine in clinical decision making and examine medicolegal and regulatory aspects of nuclear medicine.

  17. Including Jews in Multiculturalism.

    ERIC Educational Resources Information Center

    Langman, Peter F.

    1995-01-01

    Discusses reasons for the lack of attention to Jews as an ethnic minority within multiculturalism both by Jews and non-Jews; why Jews and Jewish issues need to be included; and addresses some of the issues involved in the ethical treatment of Jewish clients. (Author)

  18. Unifying the rotational and permutation symmetry of nuclear spin states: Schur-Weyl duality in molecular physics.

    PubMed

    Schmiedt, Hanno; Jensen, Per; Schlemmer, Stephan

    2016-08-21

    In modern physics and chemistry concerned with many-body systems, one of the mainstays is identical-particle-permutation symmetry. In particular, both the intra-molecular dynamics of a single molecule and the inter-molecular dynamics associated, for example, with reactive molecular collisions are strongly affected by selection rules originating in nuclear-permutation symmetry operations being applied to the total internal wavefunctions, including nuclear spin, of the molecules involved. We propose here a general tool to determine coherently the permutation symmetry and the rotational symmetry (associated with the group of arbitrary rotations of the entire molecule in space) of molecular wavefunctions, in particular the nuclear-spin functions. Thus far, these two symmetries were believed to be mutually independent and it has even been argued that under certain circumstances, it is impossible to establish a one-to-one correspondence between them. However, using the Schur-Weyl duality theorem we show that the two types of symmetry are inherently coupled. In addition, we use the ingenious representation-theory technique of Young tableaus to represent the molecular nuclear-spin degrees of freedom in terms of well-defined mathematical objects. This simplifies the symmetry classification of the nuclear wavefunction even for large molecules. Also, the application to reactive collisions is very straightforward and provides a much simplified approach to obtaining selection rules.

  19. Unifying the rotational and permutation symmetry of nuclear spin states: Schur-Weyl duality in molecular physics

    NASA Astrophysics Data System (ADS)

    Schmiedt, Hanno; Jensen, Per; Schlemmer, Stephan

    2016-08-01

    In modern physics and chemistry concerned with many-body systems, one of the mainstays is identical-particle-permutation symmetry. In particular, both the intra-molecular dynamics of a single molecule and the inter-molecular dynamics associated, for example, with reactive molecular collisions are strongly affected by selection rules originating in nuclear-permutation symmetry operations being applied to the total internal wavefunctions, including nuclear spin, of the molecules involved. We propose here a general tool to determine coherently the permutation symmetry and the rotational symmetry (associated with the group of arbitrary rotations of the entire molecule in space) of molecular wavefunctions, in particular the nuclear-spin functions. Thus far, these two symmetries were believed to be mutually independent and it has even been argued that under certain circumstances, it is impossible to establish a one-to-one correspondence between them. However, using the Schur-Weyl duality theorem we show that the two types of symmetry are inherently coupled. In addition, we use the ingenious representation-theory technique of Young tableaus to represent the molecular nuclear-spin degrees of freedom in terms of well-defined mathematical objects. This simplifies the symmetry classification of the nuclear wavefunction even for large molecules. Also, the application to reactive collisions is very straightforward and provides a much simplified approach to obtaining selection rules.

  20. Probing Electron Dynamics in Simple Molecules with Attosecond Pulses

    NASA Astrophysics Data System (ADS)

    Rivière, Paula; Palacios, Alicia; Pérez-Torres, Jhon Fredy; Martín, Fernando

    Attosecond pulses are an ideal tool to explore electron and nuclear dynamics in atoms and molecules. Either as single attosecond pulses (SAP), in attosecond pulse trains (APT), or in combination with infrared (IR) pulses, these pulses, with frequencies in the VUV-XUV regime, have been widely used to probe ionization, electron tunneling, or autoionization in atoms. More recently, similar processes have been studied in molecules. A correct theoretical description of such processes in molecules often requires a fully dimensional treatment due to the important role of nuclear motion and electron correlation. This restricts ab initio calculations to the simplest molecules. In this chapter, we discuss single ionization of hydrogen molecules (H2 and D2) induced by time-delayed SAP+IR and APT+IR schemes. Ab initio time-dependent theoretical calculations are compared with existing experiments.

  1. Molecules between the Stars.

    ERIC Educational Resources Information Center

    Verschuur, Gerrit L.

    1987-01-01

    Provides a listing of molecules discovered to date in the vast interstellar clouds of dust and gas. Emphasizes the recent discoveries of organic molecules. Discusses molecular spectral lines, MASERs (microwave amplification by stimulated emission of radiation), molecular clouds, and star birth. (TW)

  2. Molecules between the Stars.

    ERIC Educational Resources Information Center

    Verschuur, Gerrit L.

    1987-01-01

    Provides a listing of molecules discovered to date in the vast interstellar clouds of dust and gas. Emphasizes the recent discoveries of organic molecules. Discusses molecular spectral lines, MASERs (microwave amplification by stimulated emission of radiation), molecular clouds, and star birth. (TW)

  3. Nuclear Plant Inspection

    NASA Technical Reports Server (NTRS)

    1983-01-01

    Engineers from the Power Authority of the State of New York use a Crack Growth Analysis Program supplied by COSMIC (Computer Software Management and Information Center) in one stage of nuclear plant inspection. Welds of the nuclear steam supply system are checked for cracks; radiographs, dye penetration and visual inspections are performed to locate cracks in the metal structure and welds. The software package includes three separate crack growth analysis models and enables necessary repairs to be planned before serious problems develop.

  4. Porous organic molecules

    NASA Astrophysics Data System (ADS)

    Holst, James R.; Trewin, Abbie; Cooper, Andrew I.

    2010-11-01

    Most synthetic materials that show molecular-scale porosity consist of one-, two- or three-dimensional networks. Porous metal-organic frameworks in particular have attracted a lot of recent attention. By contrast, discrete molecules tend to pack efficiently in the solid state, leaving as little empty space as possible, which leads to non-porous materials. This Perspective discusses recent developments with discrete organic molecules that are porous in the solid state. Such molecules, which may be either crystalline or amorphous, can be categorized as either intrinsically porous (containing permanent covalent cavities) or extrinsically porous (inefficiently packed). We focus on the possible advantages of organic molecules over inorganic or hybrid systems in terms of molecular solubility, choice of components and functionalities, and structural mobility and responsiveness in non-covalent extended solids. We also highlight the potential for 'undiscovered' porous systems among the large number of cage-like organic molecules that are already known.

  5. Single molecule electronic devices.

    PubMed

    Song, Hyunwook; Reed, Mark A; Lee, Takhee

    2011-04-12

    Single molecule electronic devices in which individual molecules are utilized as active electronic components constitute a promising approach for the ultimate miniaturization and integration of electronic devices in nanotechnology through the bottom-up strategy. Thus, the ability to understand, control, and exploit charge transport at the level of single molecules has become a long-standing desire of scientists and engineers from different disciplines for various potential device applications. Indeed, a study on charge transport through single molecules attached to metallic electrodes is a very challenging task, but rapid advances have been made in recent years. This review article focuses on experimental aspects of electronic devices made with single molecules, with a primary focus on the characterization and manipulation of charge transport in this regime. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Nuclear privatization

    SciTech Connect

    Jeffs, E.

    1995-11-01

    The United Kingdom government announced in May 1995 plans to privatize the country`s two nuclear generating companies, Nuclear Electric and Scottish Nuclear. Under the plan, the two companies will become operating divisions of a unified holding company, to be called British Electric, with headquarters in Scotland. Britain`s nuclear plants were left out of the initial privatization in 1989 because the government believed the financial community would be unwilling to accept the open-ended liability of decommissioning the original nine stations based on the Magnox gas-cooled reactor. Six years later, the government has found a way around this by retaining these power stations in state ownership, leaving the new nuclear company with the eight Advanced Gas-cooled Reactor (AGR) stations and the recently completed Sizewell B PWR stations. The operating Magnox stations are to be transferred to BNFL, which operates two Magnox stations of their own at Calder Hall and Chapelcross.

  7. Nuclear materials

    SciTech Connect

    Not Available

    1992-08-01

    The Department of Energy (DOE) processes plutonium for use in nuclear weapons. This fact sheet responds to your September 6, 1991, request, that we describe the methods and facilities for DOE's plutonium processing. Plutonium, which is used to make nuclear weapons, does not exist in nature and has to be produced. However, DOE no longer produces plutonium for use in nuclear weapons. Instead, DOE processes and recycles the plutonium from retired nuclear weapons and the plutonium that remains as scrap or residue from plutonium processing. This paper reports that DOE recovers plutonium through two basic processes-aqueous and pyrochemical-at four processing sites-Rocky Flats, Savannah River, Hanford, and Los Alamos. However, because of environmental and safety concerns and reductions in nuclear weapons, DOE has closed or may close most of the processing facilities. Only Los Alamos' processing facilities are currently operating.

  8. Interstellar molecules and the origin of life.

    NASA Technical Reports Server (NTRS)

    Buhl, D.; Ponnamperuma, C.

    1971-01-01

    Synopsis of the various views expressed at the conference held at NASA Ames Research Center in February 1971 on the relationship of interstellar molecules to the origin of life, intended to provide a basis for future discussion and work in this area. The topics covered include: a summary of molecules discovered, the interstellar environment, laboratory measurements, chemical evolution, and exobiology.

  9. Swelling-resistant nuclear fuel

    SciTech Connect

    Arsenlis, Athanasios; Satcher, Jr., Joe; Kucheyev, Sergei O

    2011-12-27

    A nuclear fuel according to one embodiment includes an assembly of nuclear fuel particles; and continuous open channels defined between at least some of the nuclear fuel particles, wherein the channels are characterized as allowing fission gasses produced in an interior of the assembly to escape from the interior of the assembly to an exterior thereof without causing significant swelling of the assembly. Additional embodiments, including methods, are also presented.

  10. Giant molecules composed of polar molecules and atoms in mixed dimensions

    NASA Astrophysics Data System (ADS)

    Qi, Ran; Tan, Shina

    2014-05-01

    Two or three polar molecules, confined to one or two dimensions, can form stable bound states with a single atom living in three dimensions, if the molecule and the atom can interact resonantly such that their mixed dimensional scattering length is large. We call these bound states ``giant molecules'' since it's a molecule composed of smaller molecules and atoms. We study their properties using techniques including exact numerical solution, exact qunatum diffusion Monte Carlo (QMC), Born-Oppenheimer approximation (BOA), and semiclassical approximation. These bound states have a hierarchical structure reminiscent of the celestial systems.

  11. Nuclear reactor

    DOEpatents

    Yant, Howard W.; Stinebiser, Karl W.; Anzur, Gregory C.

    1977-01-01

    A nuclear reactor, particularly a liquid-metal breeder reactor, whose upper internals include outlet modules for channeling the liquid-metal coolant from selected areas of the outlet of the core vertically to the outlet plenum. The modules are composed of a highly-refractory, high corrosion-resistant alloy, for example, INCONEL-718. Each module is disposed to confine and channel generally vertically the coolant emitted from a subplurality of core-component assemblies. Each module has a grid with openings, each opening disposed to receive the coolant from an assembly of the subplurality. The grid in addition serves as a holdown for the assemblies of the corresponding subplurality preventing their excessive ejection upwardly from the core. In the region directly over the core the outlet modules are of such peripheral form that they nest forming a continuum over the core-component assemblies whose outlet coolant they confine. Each subassembly includes a chimney which confines the coolant emitted by its corresponding subassemblies to generally vertical flow between the outlet of the core and the outlet plenum. Each subplurality of assemblies whose emitted coolant is confined by an outlet module includes assemblies which emit lower-temperature coolant, for example, a control-rod assembly, or fertile assemblies, and assemblies which emit coolant of substantially higher temperature, for example, fuel-rod assemblies. The coolants of different temperatures are mixed in the chimneys reducing the effect of stripping (hot-cold temperature fluctuations) on the remainder of the upper internals which are composed typically of AISI-304 or AISI-316 stainless steel.

  12. Excited-State Energetics and Dynamics of Large Molecules, Complexes and Clusters.

    DTIC Science & Technology

    1986-10-30

    van der Waals Molecules and Microsurfaces . The binding of rare-gas (R) atoms to large aromatic molecules (M) on the one hand, and to the basal plane of...orientational registry effects and the nuclear motion of R adsorbates on finite microsurfaces . The elucidation of the structure, energetics and nuclear...Company, Holland, 1986) I... . Page 1O (13) Samuel Leutwyler and Joshua Jortner The Adsorption of Rare-Gas on Microsurfaces of Large Aromatic Molecules

  13. Efficient and dynamic nuclear localization of green fluorescent protein via RNA binding

    SciTech Connect

    Kitamura, Akira; Nakayama, Yusaku; Kinjo, Masataka

    2015-07-31

    Classical nuclear localization signal (NLS) sequences have been used for artificial localization of green fluorescent protein (GFP) in the nucleus as a positioning marker or for measurement of the nuclear-cytoplasmic shuttling rate in living cells. However, the detailed mechanism of nuclear retention of GFP-NLS remains unclear. Here, we show that a candidate mechanism for the strong nuclear retention of GFP-NLS is via the RNA-binding ability of the NLS sequence. GFP tagged with a classical NLS derived from Simian virus 40 (GFP-NLS{sup SV40}) localized not only in the nucleoplasm, but also to the nucleolus, the nuclear subdomain in which ribosome biogenesis takes place. GFP-NLS{sup SV40} in the nucleolus was mobile, and intriguingly, the diffusion coefficient, which indicates the speed of diffusing molecules, was 1.5-fold slower than in the nucleoplasm. Fluorescence correlation spectroscopy (FCS) analysis showed that GFP-NLS{sup SV40} formed oligomers via RNA binding, the estimated molecular weight of which was larger than the limit for passive nuclear export into the cytoplasm. These findings suggest that the nuclear localization of GFP-NLS{sup SV40} likely results from oligomerization mediated via RNA binding. The analytical technique used here can be applied for elucidating the details of other nuclear localization mechanisms, including those of several types of nuclear proteins. In addition, GFP-NLS{sup SV40} can be used as an excellent marker for studying both the nucleoplasm and nucleolus in living cells. - Highlights: • Nuclear localization signal-tagged GFP (GFP-NLS) showed clear nuclear localization. • The GFP-NLS dynamically localized not only in the nucleoplasm, but also to the nucleolus. • The nuclear localization of GFP-NLS results from transient oligomerization mediated via RNA binding. • Our NLS-tagging procedure is ideal for use in artificial sequestration of proteins in the nucleus.

  14. Single molecule tracking

    DOEpatents

    Shera, E. Brooks

    1988-01-01

    A detection system is provided for identifying individual particles or molecules having characteristic emission in a flow train of the particles in a flow cell. A position sensitive sensor is located adjacent the flow cell in a position effective to detect the emissions from the particles within the flow cell and to assign spatial and temporal coordinates for the detected emissions. A computer is then enabled to predict spatial and temporal coordinates for the particle in the flow train as a function of a first detected emission. Comparison hardware or software then compares subsequent detected spatial and temporal coordinates with the predicted spatial and temporal coordinates to determine whether subsequently detected emissions originate from a particle in the train of particles. In one embodiment, the particles include fluorescent dyes which are excited to fluoresce a spectrum characteristic of the particular particle. Photones are emitted adjacent at least one microchannel plate sensor to enable spatial and temporal coordinates to be assigned. The effect of comparing detected coordinates with predicted coordinates is to define a moving sample volume which effectively precludes the effects of background emissions.

  15. Single molecule tracking

    DOEpatents

    Shera, E.B.

    1987-10-07

    A detection system is provided for identifying individual particles or molecules having characteristic emission in a flow train of the particles in a flow cell. A position sensitive sensor is located adjacent the flow cell in a position effective to detect the emissions from the particles within the flow cell and to assign spatial and temporal coordinates for the detected emissions. A computer is then enabled to predict spatial and temporal coordinates for the particle in the flow train as a function of a first detected emission. Comparison hardware or software then compares subsequent detected spatial and temporal coordinates with the predicted spatial and temporal coordinates to determine whether subsequently detected emissions originate from a particle in the train of particles. In one embodiment, the particles include fluorescent dyes which are excited to fluoresce a spectrum characteristic of the particular particle. Photons are emitted adjacent at least one microchannel plate sensor to enable spatial and temporal coordinates to be assigned. The effect of comparing detected coordinates with predicted coordinates is to define a moving sample volume which effectively precludes the effects of background emissions. 3 figs.

  16. Nuclear spin circular dichroism

    SciTech Connect

    Vaara, Juha; Rizzo, Antonio; Kauczor, Joanna; Norman, Patrick; Coriani, Sonia

    2014-04-07

    Recent years have witnessed a growing interest in magneto-optic spectroscopy techniques that use nuclear magnetization as the source of the magnetic field. Here we present a formulation of magnetic circular dichroism (CD) due to magnetically polarized nuclei, nuclear spin-induced CD (NSCD), in molecules. The NSCD ellipticity and nuclear spin-induced optical rotation (NSOR) angle correspond to the real and imaginary parts, respectively, of (complex) quadratic response functions involving the dynamic second-order interaction of the electron system with the linearly polarized light beam, as well as the static magnetic hyperfine interaction. Using the complex polarization propagator framework, NSCD and NSOR signals are obtained at frequencies in the vicinity of optical excitations. Hartree-Fock and density-functional theory calculations on relatively small model systems, ethene, benzene, and 1,4-benzoquinone, demonstrate the feasibility of the method for obtaining relatively strong nuclear spin-induced ellipticity and optical rotation signals. Comparison of the proton and carbon-13 signals of ethanol reveals that these resonant phenomena facilitate chemical resolution between non-equivalent nuclei in magneto-optic spectra.

  17. The new nuclear nations

    SciTech Connect

    Spector, L.

    1985-01-01

    Using 251 pages of text, 66 pages of references and 26 pages of appendixes, Spector delves into a world of new nuclear suppliers whose voracious hunger for profits may lead them to provide unwise assistance to countries that are unduly interested in nuclear weaponry. He assails a new dragon, a 'nuclear netherworld' that would illicitly supply such items for profit or political gain. Spector's book tells of covert dealings in nuclear technologies and materials. For him, the buyers have but one goal: '... to gain possession of the knowledge and materials necessary for development of nuclear weapons'. He warns of dangers from this illicit trade, of the loopholes in existing controls and the need to close them. His warnings come wrapped in stories of undercover transactions, many about Pakistan's efforts to get what it needs for its centrifuge enrichment plant. Recognizing the tightening of controls over nuclear trade since the 1970s, including those for dual-use items, Spector is nonetheless pessimistic that these efforts are sufficient to irradicate the nuclear netherworld or to deter newcomers from it.

  18. Nutritional therapies (including fosteum).

    PubMed

    Nieves, Jeri W

    2009-03-01

    Nutrition is important in promoting bone health and in managing an individual with low bone mass or osteoporosis. In adult women and men, known losses of bone mass and microarchitecture occur, and nutrition can help minimize these losses. In every patient, a healthy diet with adequate protein, fruits, vegetables, calcium, and vitamin D is required to maintain bone health. Recent reports on nutritional remedies for osteoporosis have highlighted the importance of calcium in youth and continued importance in conjunction with vitamin D as the population ages. It is likely that a calcium intake of 1200 mg/d is ideal, and there are some concerns about excessive calcium intakes. However, vitamin D intake needs to be increased in most populations. The ability of soy products, particularly genistein aglycone, to provide skeletal benefit has been recently studied, including some data that support a new medical food marketed as Fosteum (Primus Pharmaceuticals, Scottsdale, AZ).

  19. Dynamics of Activated Molecules

    SciTech Connect

    Mullin, Amy S.

    2016-11-16

    Experimental studies have been performed to investigate the collisional energy transfer processes of gas-phase molecules that contain large amounts of internal energy. Such molecules are prototypes for molecules under high temperature conditions relevant in combustion and information about their energy transfer mechanisms is needed for a detailed understanding and modeling of the chemistry. We use high resolution transient IR absorption spectroscopy to measure the full, nascent product distributions for collisions of small bath molecules that relax highly vibrationally excited pyrazine molecules with E=38000 cm-1 of vibrational energy. To perform these studies, we developed new instrumentation based on modern IR light sources to expand our experimental capabilities to investigate new molecules as collision partners. This final report describes our research in four areas: the characterization of a new transient absorption spectrometer and the results of state-resolved collision studies of pyrazine(E) with HCl, methane and ammonia. Through this research we have gained fundamental new insights into the microscopic details of relatively large complex molecules at high energy as they undergo quenching collisions and redistribute their energy.

  20. Nuclear localization of the tight junction protein ZO-2 in epithelial cells.

    PubMed

    Islas, Socorro; Vega, Jesús; Ponce, Lissette; González-Mariscal, Lorenza

    2002-03-10

    The tight junction constitutes the major barrier to solute and water flow through the paracellular space of epithelia and endothelia. It is formed by transmembrane proteins and submembranous molecules such as the MAGUKs ZOs. We have previously found that several MAGUKs, including those of the tight (ZO-1, ZO-2, and ZO-3) and septate junction (tamou and Dlg), contain one or two nuclear sorting signals located at their first PDZ and GK domains. Now we show that these proteins also contain a nuclear export signal and focus our study on the nuclear membrane shuttling of ZO-2. In sparse cultures this molecule concentrates at the nucleus in clusters, where it partially colocalizes with splicing factor SC35. Nuclear staining diminishes as the monolayer acquires confluence through a process sensitive to the nuclear export inhibitor leptomycin B. Nuclear localization can be induced by impairing cell-cell contacts, by mechanical injury. ZO-2 that shuttles from the cell periphery into the nucleus is not newly synthesized but originates from a preexistent pool. The movement of this protein is mediated by the actin cytoskeleton.

  1. Organic Molecules in Meteorites

    NASA Astrophysics Data System (ADS)

    Martins, Zita

    2015-08-01

    Carbonaceous meteorites are primitive samples from the asteroid belt, containing 3-5wt% organic carbon. The exogenous delivery of organic matter by carbonaceous meteorites may have contributed to the organic inventory of the early Earth. The majority (>70%) of the meteoritic organic material consist of insoluble organic matter (IOM) [1]. The remaining meteoritic organic material (<30%) consists of a rich organic inventory of soluble organic compounds, including key compounds important in terrestrial biochemistry [2-4]. Different carbonaceous meteorites contain soluble organic molecules with different abundances and distributions, which may reflect the extension of aqueous alteration or thermal metamorphism on the meteorite parent bodies. Extensive aqueous alteration on the meteorite parent body may result on 1) the decomposition of α-amino acids [5, 6]; 2) synthesis of β- and γ-amino acids [2, 6-9]; 3) higher relative abundances of alkylated polycyclic aromatic hydrocarbons (PAHs) [6, 10]; and 4) higher L-enantiomer excess (Lee) value of isovaline [6, 11, 12].The soluble organic content of carbonaceous meteorites may also have a contribution from Fischer-Tropsch/Haber-Bosch type gas-grain reactions after the meteorite parent body cooled to lower temperatures [13, 14].The analysis of the abundances and distribution of the organic molecules present in meteorites helps to determine the physical and chemical conditions of the early solar system, and the prebiotic organic compounds available on the early Earth.[1] Cody and Alexander (2005) GCA 69, 1085. [2] Cronin and Chang (1993) in: The Chemistry of Life’s Origin. pp. 209-258. [3] Martins and Sephton (2009) in: Amino acids, peptides and proteins in organic chemistry. pp. 1-42. [4] Martins (2011) Elements 7, 35. [5] Botta et al. (2007) MAPS 42, 81. [6] Martins et al. (2015) MAPS, in press. [7] Cooper and Cronin (1995) GCA 59, 1003. [8] Glavin et al. (2006) MAPS. 41, 889. [9] Glavin et al. (2011) MAPS 45, 1948. [10

  2. Heavy exotic molecules

    NASA Astrophysics Data System (ADS)

    Liu, Yizhuang; Zahed, Ismail

    We briefly review the formation of pion-mediated heavy-light exotic molecules with both charm and bottom, under the general structures of chiral and heavy quark symmetries. The charm isosinglet exotic molecules with JPC = 1++ binds, which we identify as the reported neutral X(3872). The bottom isotriplet exotic with JPC = 1+- binds, and is identified as a mixed state of the reported charged exotics Zb+(10610) and Zb+(10650). The bound bottom isosinglet molecule with JPC = 1++ is a possible neutral Xb(10532) to be observed.

  3. Heavy exotic molecules

    NASA Astrophysics Data System (ADS)

    Liu, Yizhuang; Zahed, Ismail

    We briefly review the formation of pion-mediated heavy-light exotic molecules with both charm and bottom, under the general structures of chiral and heavy quark symmetries. The charm isosinglet exotic molecules with JPC = 1++ binds, which we identify as the reported neutral X(3872). The bottom isotriplet exotic with JPC = 1+1 binds, and is identified as a mixed state of the reported charged exotics Zb+(10610) and Zb-(10650). The bound bottom isosinglet molecule with JPC = 1++ is a possible neutral Xb(10532) to be observed.

  4. Nuclear reprogramming.

    PubMed

    Halley-Stott, Richard P; Pasque, Vincent; Gurdon, J B

    2013-06-01

    There is currently particular interest in the field of nuclear reprogramming, a process by which the identity of specialised cells may be changed, typically to an embryonic-like state. Reprogramming procedures provide insight into many mechanisms of fundamental cell biology and have several promising applications, most notably in healthcare through the development of human disease models and patient-specific tissue-replacement therapies. Here, we introduce the field of nuclear reprogramming and briefly discuss six of the procedures by which reprogramming may be experimentally performed: nuclear transfer to eggs or oocytes, cell fusion, extract treatment, direct reprogramming to pluripotency and transdifferentiation.

  5. Optical highlighter molecules in neurobiology

    PubMed Central

    Datta, Sandeep Robert; Patterson, George H.

    2011-01-01

    The development of advanced optical methods has played a key role in propelling progress in neurobiology. Genetically-encoded fluorescent molecules found in nature have enabled labeling of individual neurons to study their physiology and anatomy. Here we discuss the recent use of both native and synthetic optical highlighter proteins to address key problems in neurobiology, including questions relevant to synaptic function, neuroanatomy, and the organization of neural circuits. PMID:22129781

  6. Optical highlighter molecules in neurobiology.

    PubMed

    Datta, Sandeep Robert; Patterson, George H

    2012-02-01

    The development of advanced optical methods has played a key role in propelling progress in neurobiology. Genetically-encoded fluorescent molecules found in nature have enabled labeling of individual neurons to study their physiology and anatomy. Here we discuss the recent use of both native and synthetic optical highlighter proteins to address key problems in neurobiology, including questions relevant to synaptic function, neuroanatomy, and the organization of neural circuits. Copyright © 2011 Elsevier Ltd. All rights reserved.

  7. Epigenetic reprogramming by somatic cell nuclear transfer: questions and potential solutions.

    PubMed

    Huili, Ji; Haosheng, Lu; Dengke, Pan

    2014-12-01

    Somatic cell nuclear transfer (SCNT) is a technology by which a highly differentiated somatic nucleus is transferred into an enucleated oocyte to generate a reconstructed embryo that subsequently develops to an offspring. However, to date, the efficiency of cloned animal is still low. The major reason is incomplete nuclear reprogramming of donor cells after nuclear transfer, which results in abnormal epigenetic modifications, including DNA methylation, histone acetylation, gene imprinting, X-chromosome inactivation, and telomere length. Most improvements have been made in somatic epigenetic reprogramming with small molecules and manipulating expression of specific genes. It is expected that SCNT will soon have broad applications in both basic research and practical production. In this review, we summarize the recent progress in epigenetic reprogramming by somatic cell nuclear transfer; in particular, we focus on strategies for rescuing the epigenetic errors occurring during SCNT.

  8. Concise nuclear isobar charts

    SciTech Connect

    Bucka, H.

    1986-01-01

    In the Concise Nuclear Isobar Charts, data on binding energies of protons and neutrons in the ground state and excitation energies for low-lying nuclear energy levels are displayed, both of which are of great interest for transition processes as well as for questions of nuclear structure. Also, quantum numbers for angular momentum and parity are shown for these energy levels. For the stable nuclei, data for the relative abundances, and for unstable nucleon configurations, the transition probabilities are included in the data displayed. Due to the representation chosen for the atomic nuclei, in many cases a very clear first survey of systematic properties of nuclear energy states as well as spontaneous decay processes is achieved.

  9. Nuclear Mechanics in Disease

    PubMed Central

    Zwerger, Monika; Ho, Chin Yee; Lammerding, Jan

    2015-01-01

    Over the past two decades, the biomechanical properties of cells have emerged as key players in a broad range of cellular functions, including migration, proliferation, and differentiation. Although much of the attention has focused on the cytoskeletal networks and the cell’s microenvironment, relatively little is known about the contribution of the cell nucleus. Here, we present an overview of the structural elements that determine the physical properties of the nucleus and discuss how changes in the expression of nuclear components or mutations in nuclear proteins can affect not only nuclear mechanics but also modulate cytoskeletal organization and diverse cellular functions. These findings illustrate that the nucleus is tightly integrated into the surrounding cellular structure. Consequently, changes in nuclear structure and composition are highly relevant to normal development and physiology and can contribute to many human diseases, such as muscular dystrophy, dilated cardiomyopathy, (premature) aging, and cancer. PMID:21756143

  10. Refraction, including prisms.

    PubMed

    Hiatt, R L

    1991-02-01

    The literature in the past year on refraction is replete with several isolated but very important topics that have been of interest to strabismologists and refractionists for many decades. The refractive changes in scleral buckling procedures include an increase in axial length as well as an increase in myopia, as would be expected. Tinted lenses in dyslexia show little positive effect in the nonasthmatic patients in one study. The use of spectacles or bifocals as a way to control increase in myopia is refuted in another report. It has been shown that in accommodative esotropia not all patients will be able to escape the use of bifocals in the teenage years, even though surgery might be performed. The hope that disposable contact lenses would cut down on the instance of giant papillary conjunctivitis and keratitis has been given some credence, and the conventional theory that sclerosis alone is the cause of presbyopia is attacked. Also, gas permeable bifocal contact lenses are reviewed and the difficulties of correcting presbyopia by this method outlined. The practice of giving an aphakic less bifocal addition instead of a nonaphakic, based on the presumption of increased effective power, is challenged. In the review of prisms, the majority of articles concern prism adaption. The most significant report is that of the Prism Adaptation Study Research Group (Arch Ophthalmol 1990, 108:1248-1256), showing that acquired esotropia in particular has an increased incidence of stable and full corrections surgically in the prism adaptation group versus the control group.(ABSTRACT TRUNCATED AT 250 WORDS)

  11. (Nuclear theory). [Research in nuclear physics

    SciTech Connect

    Haxton, W.

    1990-01-01

    This report discusses research in nuclear physics. Topics covered in this paper are: symmetry principles; nuclear astrophysics; nuclear structure; quark-gluon plasma; quantum chromodynamics; symmetry breaking; nuclear deformation; and cold fusion. (LSP)

  12. Of Molecules and Models.

    ERIC Educational Resources Information Center

    Brinner, Bonnie

    1992-01-01

    Presents an activity in which models help students visualize both the DNA process and transcription. After constructing DNA, RNA messenger, and RNA transfer molecules; students model cells, protein synthesis, codons, and RNA movement. (MDH)

  13. Single-Molecule Enzymology

    SciTech Connect

    Xie, Xiaoliang; Lu, H PETER.

    1999-06-04

    Viewing a movie of an enzyme molecule made from molecular dynamics (MD) simulation, we see incredible details of molecular motions, be it a change of the conformation or the action of a chemical reaction.

  14. Of Molecules and Models.

    ERIC Educational Resources Information Center

    Brinner, Bonnie

    1992-01-01

    Presents an activity in which models help students visualize both the DNA process and transcription. After constructing DNA, RNA messenger, and RNA transfer molecules; students model cells, protein synthesis, codons, and RNA movement. (MDH)

  15. Nuclear battlefields

    SciTech Connect

    Arkin, W.M.; Fieldhouse, R.W.

    1985-01-01

    This book provides complete data on the nuclear operations and research facilities in the U.S.A., the U.S.S.R., France, China and the U.K. It describes detailed estimates on the U.S.S.R.'s nuclear stockpile for over 500 locations. It shows how non-nuclear countries cooperate with the world-wide war machine. And it maps the U.S. nuclear facilities from Little America, WY, and Charleston, SC, to the battleships patroling the world's oceans and subs stalking under the sea. The data were gathered from unclassified sources through the Freedom of Information Act, from data supplied to military installations, and from weapons source books. It provides guidance for policymakers, government and corporate officials.

  16. NUCLEAR REACTOR

    DOEpatents

    Sherman, J.; Sharbaugh, J.E.; Fauth, W.L. Jr.; Palladino, N.J.; DeHuff, P.G.

    1962-10-23

    A nuclear reactor incorporating seed and blanket assemblies is designed. Means are provided for obtaining samples of the coolant from the blanket assemblies and for varying the flow of coolant through the blanket assemblies. (AEC)

  17. Nuclear Nonproliferation

    SciTech Connect

    Atkins-Duffin, C E

    2008-12-10

    With an explosion equivalent of about 20kT of TNT, the Trinity test was the first demonstration of a nuclear weapon. Conducted on July 16, 1945 in Alamogordo, NM this site is now a Registered National Historic Landmark. The concept and applicability of nuclear power was demonstrated on December 20, 1951 with the Experimental Breeder Reactor Number One (EBR-1) lit four light bulbs. This reactor is now a Registered National Historic Landmark, located near Arco, ID. From that moment forward it had been clearly demonstrated that nuclear energy has both peaceful and military applications and that the civilian and military fuel cycles can overlap. For the more than fifty years since the Atoms for Peace program, a key objective of nuclear policy has been to enable the wider peaceful use of nuclear energy while preventing the spread of nuclear weapons. Volumes have been written on the impact of these two actions on the world by advocates and critics; pundits and practioners; politicians and technologists. The nations of the world have woven together a delicate balance of treaties, agreements, frameworks and handshakes that are representative of the timeframe in which they were constructed and how they have evolved in time. Collectively these vehicles attempt to keep political will, nuclear materials and technology in check. This paper captures only the briefest abstract of the more significant aspects on the Nonproliferation Regime. Of particular relevance to this discussion is the special nonproliferation sensitivity associated with the uranium isotope separation and spent fuel reprocessing aspects of the nuclear fuel cycle.

  18. Nuclear Data

    SciTech Connect

    White, Morgan C.

    2014-01-23

    PowerPoint presentation targeted for educational use. Nuclear data comes from a variety of sources and in many flavors. Understanding where the data you use comes from and what flavor it is can be essential to understand and interpret your results. This talk will discuss the nuclear data pipeline with particular emphasis on providing links to additional resources that can be used to explore the issues you will encounter.

  19. Nuclear cardiac

    SciTech Connect

    Slutsky, R.; Ashburn, W.L.

    1982-01-01

    The relationship between nuclear medicine and cardiology has continued to produce a surfeit of interesting, illuminating, and important reports involving the analysis of cardiac function, perfusion, and metabolism. To simplify the presentation, this review is broken down into three major subheadings: analysis of myocardial perfusion; imaging of the recent myocardial infarction; and the evaluation of myocardial function. There appears to be an increasingly important relationship between cardiology, particularly cardiac physiology, and nuclear imaging techniques. (KRM)

  20. Laser Spectroscopy of Atoms and Molecules.

    ERIC Educational Resources Information Center

    Schawlow, Arthur L.

    1978-01-01

    Surveys new laser techniques and a variety of spectroscopic experiments that can be used to detect, measure and study very small numbers of atoms on molecules. The range of applicability of these techniques is also included. (HM)

  1. Polyatomic molecule vibrations

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Polyatomic molecule vibrations are analyzed as harmonic vibrations along normal coordinates. The energy eigenvalues are found for linear and nonlinear symmetric triatomic molecules for valence bond models of the potential function with arbitrary coupling coefficients; such models can usually be fitted to observed energy levels with reasonably good accuracy. Approximate normal coordinates for the H2O molecule are discussed. Degenerate vibrational modes such as occur in CO2 are analyzed and expressions for Fermi resonance between close-lying states of the same symmetry are developed. The bending modes of linear triatomic molecules are expressed in terms of Laguerre polynomials in cylindrical coordinates as well as in terms of Hermite polynomials in Cartesian coordinates. The effects of large-amplitude bending such as occur in the C3 molecule are analyzed, along with anharmonic effects, which split the usually degenerate bending mode energy levels. Finally, the vibrational frequencies, degeneracies, and symmetry properties of XY3, X2Y2, and XY4 type molecules are discussed.

  2. Nuclear telemedicine

    NASA Astrophysics Data System (ADS)

    Morrison, R. T.; Szasz, I. J.

    1990-06-01

    Diagnostic nuclear medicine patient images have been transniitted for 8 years from a regional conununity hospital to a university teaching hospital 700 kiloinetres away employing slow scan TV and telephone. Transruission and interpretation were done at the end of each working day or as circumstances required in cases of emergencies. Referring physicians received the nuclear medicine procedure report at the end of the completion day or within few minutes of completion in case of emergency procedures. To date more than 25 patient studies have been transmitted for interpretation. Blinded reinterpretation of the original hard copy data of 350 patient studies resulted in 100 agreement with the interpretation of transmitted data. This technique provides high quality diagnostic and therapeutic nuclear medicine services in remote hospitals where the services of an on-site nuclear physician is not available. 2. HISTORY Eight years ago when the nuclear medicine physician at Trail Regional Hospital left the Trail area and an other could not be recruited we examined the feasibility of image transmission by phone for interpretation since closing the department would have imposed unacceptable physical and financial hardship and medical constraints on the patient population the nearest nuclear medicine facility was at some 8 hours drive away. In hospital patients would have to be treated either based purely on physical findings or flown to Vancouver at considerable cost to the health care system (estimated cost $1500.

  3. Nuclear gas core propulsion research program

    NASA Technical Reports Server (NTRS)

    Diaz, Nils J.; Dugan, Edward T.; Anghaie, Samim

    1993-01-01

    Viewgraphs on the nuclear gas core propulsion research program are presented. The objectives of this research are to develop models and experiments, systems, and fuel elements for advanced nuclear thermal propulsion rockets. The fuel elements under investigation are suitable for gas/vapor and multiphase fuel reactors. Topics covered include advanced nuclear propulsion studies, nuclear vapor thermal rocket (NVTR) studies, and ultrahigh temperature nuclear fuels and materials studies.

  4. The nuclear electric quadrupole moment of antimony from the molecular method.

    PubMed

    Haiduke, Roberto L A; da Silva, Albérico B F; Visscher, Lucas

    2006-08-14

    Relativistic Dirac-Coulomb (DC) Hartree-Fock calculations are employed to obtain the analytic electric field gradient (EFG) on the antimony nucleus in the SbN, SbP, SbF, and SbCl molecules. The electronic correlation contribution to the EFGs is included with the DC-CCSD(T) and DC-CCSD-T approaches, also in the four-component framework, using a finite-difference method. The total EFG results, along with the experimental nuclear quadrupole coupling constants from microwave spectroscopy, allow to derive the nuclear quadrupole moments of (121)Sb and (123)Sb, respectively, as -543(11) and -692(14) mb.

  5. HLA molecules in autoimmune diseases.

    PubMed

    Braun, W E

    1992-06-01

    The association of certain autoimmune diseases with HLA molecules is being refined through the use of sequence-specific oligonucleotide probes and amino acid sequencing, together with continuing elucidation of the functional features of HLA molecules derived from the milestone description by Bjorkman of the HLA molecular structure. The association of insulin-dependent diabetes mellitus and HLA began with weak associations of Class I antigens (B8 and B15) and progressed to Class II antigens (DR3 and DR4), then to subtypes of DR4 (Dw4, 10, and 14), and now to DQ molecules including the absence of aspartic acid at position 57 of the DQ beta chain and the presence of arginine at position 52 of the DQ alpha chain. In rheumatoid arthritis (RA) the HLA antigen association remains with certain Class II molecules of the DR series (DR4 and DR1) that share amino acid sequences with a restricted number of other DR antigens seen in RA, as well as a segment of the gp 110 protein of the Epstein-Barr virus. Although ankylosing spondylitis has a strong association with the Class I antigen B27, that association is not explained by any of the B27 subtypes defined by monoclonal antibodies, by the eight variable amino acids in B27 subtypes, or by the two unique amino acids on B27. The remarkable antibody cross-reactivity among lymphocytes bearing B27, a synthetic peptide sequence (63-84) of B27, and the 188-193 sequence of K. pneumoniae nitrogenase has provided strong support for molecular mimicry being an important mechanism in the association of HLA molecules with disease.(ABSTRACT TRUNCATED AT 250 WORDS)

  6. NRC - regulator of nuclear safety

    SciTech Connect

    1997-05-01

    The U.S. Nuclear Regulatory Commission (NRC) was formed in 1975 to regulate the various commercial and institutional uses of nuclear energy, including nuclear power plants. The agency succeeded the Atomic Energy Commission, which previously had responsibility for both developing and regulating nuclear activities. Federal research and development work for all energy sources, as well as nuclear weapons production, is now conducted by the U.S. Department of Energy. Under its responsibility to protect public health and safety, the NRC has three principal regulatory functions: (1) establish standards and regulations, (2) issue licenses for nuclear facilities and users of nuclear materials, and (3) inspect facilities and users of nuclear materials to ensure compliance with the requirements. These regulatory functions relate to both nuclear power plants and to other uses of nuclear materials - like nuclear medicine programs at hospitals, academic activities at educational institutions, research work, and such industrial applications as gauges and testing equipment. The NRC places a high priority on keeping the public informed of its work. The agency recognizes the interest of citizens in what it does through such activities as maintaining public document rooms across the country and holding public hearings, public meetings in local areas, and discussions with individuals and organizations.

  7. Next-generation Nuclear Data Web Services

    NASA Astrophysics Data System (ADS)

    Sonzogni, A. A.

    2005-07-01

    The National Nuclear Data Center collects, evaluates, and disseminates nuclear physics data for basic nuclear research and applied nuclear technologies. We have recently produced a nuclear data portal featuring modern and powerful servers, relational database software, Linux operating system, and Java programming language. The portal includes nuclear structure, decay and reaction data, as well as literature information. Data can be searched for using optimized query forms; results are presented in tables and interactive plots. Additionally, a number of nuclear science tools, codes, applications, and links are provided. A brief tutorial of the different databases and products will be provided.

  8. Novel features of nuclear chromodynamics

    NASA Astrophysics Data System (ADS)

    Brodsky, Stanley J.

    2017-03-01

    I review a number of QCD topics where the nuclear environment provides new insights into fundamental aspects of the strong interactions. The topics include novel perspectives for nuclear physics, such as the hidden color of nuclear form factors, the relation of the nuclear force at short distances to quark interchange interactions, the effects of "color transparency" on the baryon-to-meson anomaly in hard heavy-ion colisions, flavor-dependent antishadowing, novel exotic multiquark states, the anomalous nuclear dependence of quarkonium hadroproduction, flavor-dependent antishadowing, and the breakdown of sum rules for nuclear structure functions. I also briefly discuss the insights into hadron physics and color confinement that one obtains from light-front holography, including supersymmetric features of the hadron spectrum. I also note that the virtual Compton amplitude on a proton (or nucleus) can be measured for two spacelike photons q21, q22 < 0 using positronium-proton scattering [e+e-]p→ e+e-p'.

  9. Nuclear cardiology in China: 2017.

    PubMed

    Tang, Gongshun

    2017-07-10

    This paper provides the current state of nuclear cardiology in China and contrasts it with the state of nuclear cardiology in the United States (US). The West China Hospital and New York-Presbyterian Hospital (NYPH) were used as representative hospitals to contrast nuclear cardiology in China and the US, respectively. In 2015, there were 101 medical cyclotrons, 774 SPECT or SPECT/CT, 240 PET/CT, and 6 PET/MR cameras in China. Most (~90%) of the nuclear cardiology studies are gated SPECT myocardial perfusion imaging (MPI), and ~10% are other types of studies including MUGA, PET/CT MPI, and viability studies. There are differences in nuclear cardiology between the West China Hospital and NYPH and these include those in cardiac stress tests, SPECT/CT acquisition protocols, PET/CT blood flow and viability studies, reimbursement, and fellowship training. In this paper, we aim to present status of nuclear cardiology in China and provide potential solutions.

  10. Nuclear medicine annual, 1987

    SciTech Connect

    Freeman, L.M.; Weissmann, H.S.

    1987-01-01

    Radionuclide evaluation of brain death, bone imaging with SPECT, and lymphoscintigraphy are among the topics covered in Nuclear Medicine Annual, 1987. In addition, the book includes reviews of the role of nuclear medicine in the diagnosis of the Acquired Immunodeficiency Syndrome (AIDS) and in the management of patients with acute myocardial infarction. Reports describe advances in radionuclide and magnetic resonance imaging of the adrenal gland and assess the current status of diuretic renography. Also included are articles on changes in functional imaging with aging, on radionuclide evaluation of the lower genitourinary tract in children, and on cholescintigraphy in children.

  11. Nuclear reactor

    DOEpatents

    Pennell, William E.; Rowan, William J.

    1977-01-01

    A nuclear reactor in which the core components, including fuel-rod assemblies, control-rod assemblies, fertile rod-assemblies, and removable shielding assemblies, are supported by a plurality of separate inlet modular units. These units are referred to as inlet module units to distinguish them from the modules of the upper internals of the reactor. The modular units are supported, each removable independently of the others, in liners in the supporting structure for the lower internals of the reactor. The core assemblies are removably supported in integral receptacles or sockets of the modular units. The liners, units, sockets and assmblies have inlet openings for entry of the fluid. The modular units are each removably mounted in the liners with fluid seals interposed between the opening in the liner and inlet module into which the fluid enters and the upper and lower portion of the liner. Each assembly is similarly mounted in a corresponding receptacle with fluid seals interposed between the openings where the fluid enters and the lower portion of the receptacle or fitting closely in these regions. As fluid flows along each core assembly a pressure drop is produced along the fluid so that the fluid which emerges from each core assembly is at a lower pressure than the fluid which enters the core assembly. However because of the seals interposed in the mountings of the units and assemblies the pressures above and below the units and assemblies are balanced and the units are held in the liners and the assemblies are held in the receptacles by their weights as they have a higher specific gravity than the fluid. The low-pressure spaces between each module and its liner and between each core assembly and its module is vented to the low-pressure regions of the vessel to assure that fluid which leaks through the seals does not accumulate and destroy the hydraulic balance.

  12. Atom-diatom scattering dynamics of spinning molecules

    SciTech Connect

    Eyles, C. J.; Floß, J.; Averbukh, I. Sh.; Leibscher, M.

    2015-01-14

    We present full quantum mechanical scattering calculations using spinning molecules as target states for nuclear spin selective atom-diatom scattering of reactive D+H{sub 2} and F+H{sub 2} collisions. Molecules can be forced to rotate uni-directionally by chiral trains of short, non-resonant laser pulses, with different nuclear spin isomers rotating in opposite directions. The calculations we present are based on rotational wavepackets that can be created in this manner. As our simulations show, target molecules with opposite sense of rotation are predominantly scattered in opposite directions, opening routes for spatially and quantum state selective scattering of close chemical species. Moreover, two-dimensional state resolved differential cross sections reveal detailed information about the scattering mechanisms, which can be explained to a large degree by a classical vector model for scattering with spinning molecules.

  13. Prospects for nuclear safety research

    SciTech Connect

    Beckjord, E.S.

    1995-04-01

    This document is the text of a paper presented by Eric S. Beckjord (Director, Nuclear Regulatory Research/NRC) at the 22nd Water Reactor Safety Meeting in Bethesda, MD in October 1994. The following topics are briefly reviewed: (1) Reactor vessel research, (2) Probabilistic risk assessment, (3) Direct containment heating, (4) Advanced LWR research, (5) Nuclear energy prospects in the US, and (6) Future nuclear safety research. Subtopics within the last category include economics, waste disposal, and health and safety.

  14. Management of National Nuclear Power Programs for assured safety

    SciTech Connect

    Connolly, T.J.

    1985-01-01

    Topics discussed in this report include: nuclear utility organization; before the Florida Public Service Commission in re: St. Lucie Unit No. 2 cost recovery; nuclear reliability improvement and safety operations; nuclear utility management; training of nuclear facility personnel; US experience in key areas of nuclear safety; the US Nuclear Regulatory Commission - function and process; regulatory considerations of the risk of nuclear power plants; overview of the processes of reliability and risk management; management significance of risk analysis; international and domestic institutional issues for peaceful nuclear uses; the role of the Institute of Nuclear Power Operations (INPO); and nuclear safety activities of the International Atomic Energy Agency (IAEA).

  15. Understanding ultracold polar molecules

    NASA Astrophysics Data System (ADS)

    Julienne, Paul

    2009-05-01

    The successful production of a dense sample of ultracold ground state KRb polar molecules [1] opens the door to a new era of research with dipolar gases and lattices of such species. This feat was achieved by first associating a K and a Rb atom to make a weakly bound Feshbach molecule and then coherently transferring the population to the ground vibrational level of the molecule. This talk focuses on theoretical issues associated with making and using ultracold polar molecules, using KRb as an example [2]. Full understanding of this species and the processes by which it is made requires taking advantage of accurate molecular potentials [3], ab initio calculations [4], and the properties of the long-range potential. A highly accurate model is available for KRb for all bound states below the ground state separated atom limit and could be constructed for other species. The next step is to develop an understanding of the interactions between polar molecules, and their control in the ultracold domain. Understanding long-range interactions and threshold resonances will be crucial for future work. [1] K.-K. Ni, et al, Science 322, 231(2008). [2] P. S. Julienne, arXiv:0812:1233. [3] Pashov et al., Phys. Rev. A76, 022511 (2007). [4] S. Kotochigova, et al., arXiv:0901.1486.

  16. Nuclear Rocket Technology Conference

    NASA Technical Reports Server (NTRS)

    1966-01-01

    The Lewis Research Center has a strong interest in nuclear rocket propulsion and provides active support of the graphite reactor program in such nonnuclear areas as cryogenics, two-phase flow, propellant heating, fluid systems, heat transfer, nozzle cooling, nozzle design, pumps, turbines, and startup and control problems. A parallel effort has also been expended to evaluate the engineering feasibility of a nuclear rocket reactor using tungsten-matrix fuel elements and water as the moderator. Both of these efforts have resulted in significant contributions to nuclear rocket technology. Many successful static firings of nuclear rockets have been made with graphite-core reactors. Sufficient information has also been accumulated to permit a reasonable Judgment as to the feasibility of the tungsten water-moderated reactor concept. We therefore consider that this technoIogy conference on the nuclear rocket work that has been sponsored by the Lewis Research Center is timely. The conference has been prepared by NASA personnel, but the information presented includes substantial contributions from both NASA and AEC contractors. The conference excludes from consideration the many possible mission requirements for nuclear rockets. Also excluded is the direct comparison of nuclear rocket types with each other or with other modes of propulsion. The graphite reactor support work presented on the first day of the conference was partly inspired through a close cooperative effort between the Cleveland extension of the Space Nuclear Propulsion Office (headed by Robert W. Schroeder) and the Lewis Research Center. Much of this effort was supervised by Mr. John C. Sanders, chairman for the first day of the conference, and by Mr. Hugh M. Henneberry. The tungsten water-moderated reactor concept was initiated at Lewis by Mr. Frank E. Rom and his coworkers. The supervision of the recent engineering studies has been shared by Mr. Samuel J. Kaufman, chairman for the second day of the

  17. Electric power monthly, September 1990. [Glossary included

    SciTech Connect

    Not Available

    1990-12-17

    The purpose of this report is to provide energy decision makers with accurate and timely information that may be used in forming various perspectives on electric issues. The power plants considered include coal, petroleum, natural gas, hydroelectric, and nuclear power plants. Data are presented for power generation, fuel consumption, fuel receipts and cost, sales of electricity, and unusual occurrences at power plants. Data are compared at the national, Census division, and state levels. 4 figs., 52 tabs. (CK)

  18. Nuclear risk

    SciTech Connect

    Levenson, M.

    1989-01-01

    The title of our session, Nuclear Risk Versus Other Power Options, is provocative. It is also a title with different meanings to different people. To the utility chief executive officer, nuclear power is a high-risk financial undertaking because of political and economic barriers to cost recovery. To the utility dispatcher, it is a high-risk future power source since plant completion and start-up dates can be delayed for very long times due to uncertain legal and political issues. To the environmentalist, concerned about global effects such as greenhouse and acid rain, nuclear power is a relatively low risk energy source. To the financial people, nuclear power is a cash cow turned sour because of uncertainties as to what new plants will cost and whether they will even be allowed to operate. The statistics on risk are known and the results of probability risk assessment calculations of risks are known. The challenge is not to make nuclear power safer, it is already one of the safest, if not the safest, source of power currently available. The challenge is to find a way to communicate this to the public.

  19. Biological signaling by small inorganic molecules.

    PubMed

    Basudhar, Debashree; Ridnour, Lisa A; Cheng, Robert; Kesarwala, Aparna H; Heinecke, Julie; Wink, David A

    2016-01-01

    Small redox active molecules such as reactive nitrogen and oxygen species and hydrogen sulfide have emerged as important biological mediators that are involved in various physiological and pathophysiological processes. Advancement in understanding of cellular mechanisms that tightly regulate both generation and reactivity of these molecules is central to improved management of various disease states including cancer and cardiovascular dysfunction. Imbalance in the production of redox active molecules can lead to damage of critical cellular components such as cell membranes, proteins and DNA and thus may trigger the onset of disease. These small inorganic molecules react independently as well as in a concerted manner to mediate physiological responses. This review provides a general overview of the redox biology of these key molecules, their diverse chemistry relevant to physiological processes and their interrelated nature in cellular signaling.

  20. Geometric phase and gauge connection in polyatomic molecules.

    PubMed

    Wittig, Curt

    2012-05-14

    Geometric phase is an interesting topic that is germane to numerous and varied research areas: molecules, optics, quantum computing, quantum Hall effect, graphene, and so on. It exists only when the system of interest interacts with something it perceives as exterior. An isolated system cannot display geometric phase. This article addresses geometric phase in polyatomic molecules from a gauge field theory perspective. Gauge field theory was introduced in electrodynamics by Fock and examined assiduously by Weyl. It yields the gauge field A(μ), particle-field couplings, and the Aharonov-Bohm phase, while Yang-Mills theory, the cornerstone of the standard model of physics, is a template for non-Abelian gauge symmetries. Electronic structure theory, including nonadiabaticity, is a non-Abelian gauge field theory with matrix-valued covariant derivative. Because the wave function of an isolated molecule must be single-valued, its global U(1) symmetry cannot be gauged, i.e., products of nuclear and electron functions such as χ(n)ψ(n) are forbidden from undergoing local phase transformation on R, where R denotes nuclear degrees of freedom. On the other hand, the synchronous transformations (first noted by Mead and Truhlar): ψ(n)→ψ(n)e(iζ) and simultaneously χ(n)→χ(n)e(-iζ), preserve single-valuedness and enable wave functions in each subspace to undergo phase transformation on R. Thus, each subspace is compatible with a U(1) gauge field theory. The central mathematical object is Berry's adiabatic connection i, which serves as a communication link between the two subsystems. It is shown that additions to the connection according to the gauge principle are, in fact, manifestations of the synchronous (e(iζ)/e(-iζ)) nature of the ψ(n) and χ(n) phase transformations. Two important U(1) connections are reviewed: qA(μ) from electrodynamics and Berry's connection. The gauging of SU(2) and SU(3) is reviewed and then used with molecules. The largest gauge

  1. Tris(tert-butoxy)siloxy derivatives of boron, including the boronous acid HOB[OSi(O(t)Bu)(3)](2) and the metal (siloxy)boryloxide complex Cp(2)Zr(Me)OB[OSi(O(t)Bu)(3)](2): a remarkable crystal structure with 18 independent molecules in its asymmetric unit.

    PubMed

    Fujdala, Kyle L; Oliver, Allen G; Hollander, Frederick J; Tilley, T Don

    2003-02-24

    Silanolysis of B(O(t)Bu)(3) with 2 and 3 equiv of HOSi(O(t)Bu)(3) led to the formation of (t)BuOB[OSi(O(t)Bu)(3)](2) (1) and B[OSi(O(t)Bu)(3)](3) (2), respectively. Compounds 1 and 2 are efficient single-source molecular precursors to B/Si/O materials via thermolytic routes in nonpolar media, as demonstrated by the generation of BO(1.5).2SiO(2) (BOSi2(xg)) and BO(1.5).3SiO(2) (BOSi3(xg)) xerogels, respectively. Use of a block copolymer template provided B/Si/O materials (BOSi2(epe) and BOSi3(epe)) with a broad distribution of mesopores (by N(2) porosimetry) and smaller, more uniform particle sizes (by TEM) as compared to the nontemplated materials. Hydrolyses of 1 and 2 with excess H(2)O resulted in formation of the expected amounts of (t)BuOH and HOSi(O(t)Bu)(3); however, reaction of 1 with 1 equiv of H(2)O led to isolation of the new boronous acid HOB[OSi(O(t)Bu)(3)](2) (3). This ligand precursor is well suited for the synthesis of new metal (siloxy)boryloxide complexes via proton-transfer reactions involving the BOH group. The reaction of 3 with Cp(2)ZrMe(2) resulted in formation of Cp(2)Zr(Me)OB[OSi(O(t)Bu)(3)](2) (4) in high yield. This rare example of a transition metal boryloxide complex crystallizes in the triclinic space group Ponemacr; and exhibits a crystal structure with an unprecedented number of independent molecules in its asymmetric unit (i.e., Z' = 18 and Z = 36). This unusual crystal structure presented an opportunity to perform statistical analyses of the metric parameters for the 18 crystallographically independent molecules. Complex 4 readily converts to Cp(2)Zr[OSi(O(t)Bu)(3)](2) (5) upon thermolysis or upon dissolution in Et(2)O at room temperature.

  2. Single-Molecule Bioelectronics

    PubMed Central

    Rosenstein, Jacob K.; Lemay, Serge G.; Shepard, Kenneth L.

    2014-01-01

    Experimental techniques which interface single biomolecules directly with microelectronic systems are increasingly being used in a wide range of powerful applications, from fundamental studies of biomolecules to ultra-sensitive assays. Here we review several technologies which can perform electronic measurements of single molecules in solution: ion channels, nanopore sensors, carbon nanotube field-effect transistors, electron tunneling gaps, and redox cycling. We discuss the shared features among these techniques that enable them to resolve individual molecules, and discuss their limitations. Recordings from each of these methods all rely on similar electronic instrumentation, and we discuss the relevant circuit implementations and potential for scaling these single-molecule bioelectronic interfaces to high-throughput arrayed sensing platforms. PMID:25529538

  3. MOLECULES IN {eta} CARINAE

    SciTech Connect

    Loinard, Laurent; Menten, Karl M.; Guesten, Rolf; Zapata, Luis A.; Rodriguez, Luis F.

    2012-04-10

    We report the detection toward {eta} Carinae of six new molecules, CO, CN, HCO{sup +}, HCN, HNC, and N{sub 2}H{sup +}, and of two of their less abundant isotopic counterparts, {sup 13}CO and H{sup 13}CN. The line profiles are moderately broad ({approx}100 km s{sup -1}), indicating that the emission originates in the dense, possibly clumpy, central arcsecond of the Homunculus Nebula. Contrary to previous claims, CO and HCO{sup +} do not appear to be underabundant in {eta} Carinae. On the other hand, molecules containing nitrogen or the {sup 13}C isotope of carbon are overabundant by about one order of magnitude. This demonstrates that, together with the dust responsible for the dimming of {eta} Carinae following the Great Eruption, the molecules detected here must have formed in situ out of CNO-processed stellar material.

  4. Molecules as Automata

    NASA Astrophysics Data System (ADS)

    Cardelli, Luca

    Molecular biology investigates the structure and function of biochemical systems starting from their basic building blocks: macromolecules. A macromolecule is a large, complex molecule (a protein or a nucleic acid) that usually has inner mutable state and external activity. Informal explanations of biochemical events trace individual macromolecules through their state changes and their interaction histories: a macromolecule is endowed with an identity that is retained through its transformations, even through changes in molecular energy and mass. A macromolecule, therefore, is qualitatively different from the small molecules of inorganic chemistry. Such molecules are stateless: in the standard notation for chemical reactions they are seemingly created and destroyed, and their atomic structure is used mainly for the bookkeeping required by the conservation of mass.

  5. Photochemistry of interstellar molecules

    NASA Technical Reports Server (NTRS)

    Stief, L. J.

    1971-01-01

    The photochemistry of two diatomic and eight polyatomic molecules is discussed quantitatively. For an interstellar molecule, the lifetime against photodecomposition depends upon the absorption cross section, the quantum yield or probability of dissociation following photon absorption, and the interstellar radiation field. The constant energy density of Habing is used for the unobserved regions of interstellar radiation field, and the field in obscuring clouds is estimated by combining the constant flux with the observed interstellar extinction curve covering the visible and ultraviolet regions. Lifetimes against photodecomposition in the unobscured regions and as a function of increasing optical thickness in obscuring clouds are calculated for the ten species. The results show that, except for CO, all the molecules have comparable lifetimes of less than one hundred years. Thus they can exist only in dense clouds and can never have been exposed to the unobscured radiation. The calculations further show that the lifetimes in clouds of moderate opacity are of the order of one million years.

  6. Nuclear Energy, Nuclear Weapons Proliferation, and the Arms Race.

    ERIC Educational Resources Information Center

    Hollander, Jack, Ed.

    A symposium was organized to reexamine the realities of vertical proliferation between the United States and the Soviet Union and to place into perspective the horizontal proliferation of nuclear weapons throughout the world, including the possible role of commercial nuclear power in facilitating proliferation. The four invited symposium…

  7. Nuclear scales

    SciTech Connect

    Friar, J.L.

    1998-12-01

    Nuclear scales are discussed from the nuclear physics viewpoint. The conventional nuclear potential is characterized as a black box that interpolates nucleon-nucleon (NN) data, while being constrained by the best possible theoretical input. The latter consists of the longer-range parts of the NN force (e.g., OPEP, TPEP, the {pi}-{gamma} force), which can be calculated using chiral perturbation theory and gauged using modern phase-shift analyses. The shorter-range parts of the force are effectively parameterized by moments of the interaction that are independent of the details of the force model, in analogy to chiral perturbation theory. Results of GFMC calculations in light nuclei are interpreted in terms of fundamental scales, which are in good agreement with expectations from chiral effective field theories. Problems with spin-orbit-type observables are noted.

  8. Nuclear astrophysics

    SciTech Connect

    Penionzhkevich, Yu. E.

    2010-08-15

    The International Year of Astronomy 2009 (IYA2009) was declared by the 62nd General Assembly of the United Nations and was also endorsed by UNESCO. Investigations in the realms of particle and nuclear physicsmake a large contribution in the development of our ideas of the properties of the Universe. The present article discusses some problems of the evolution of the Universe, nucleosyntheses, and cosmochronology from the point of view of nuclear and particle physics. Processes occurring in the Universe are compared with the mechanisms of the production and decay of nuclei, as well as with the mechanisms of their interaction at high energies. Examples that demonstrate the potential of nuclearphysics methods for studying cosmic objects and the properties of the Universe are given. The results that come from investigations into nuclear reactions induced by beams of radioactive nuclei and which make it possible to take a fresh look at the nucleosynthesis scenario in the range at light nuclei are presented.

  9. Nuclear waste

    SciTech Connect

    Not Available

    1988-05-01

    This paper discusses how, as part of the Department of Energy's implementation of the Nuclear Waste Policy Act of 1982, DOE is required to investigate a site at Yucca Mountain, Nevada and, if it determines that the site is suitable, recommend to the President its selection for a nuclear waste repository. The Nuclear Regulatory Commission, in considering development of the plan, issued five objections, one of which is DOE's failure to recognize the range of alternative conceptual models of the Yucca Mountain site that can be supported by the limited existing technical data. At the end of the quarter DOE directed its project offices in Washington and Texas to begin orderly phase-out of all site-specific repository activities. Costs for this phase-out are $53 million for the Deaf Smith site and $85 million for the Hanford site.

  10. Waging nuclear peace: The technology and politics of nuclear war

    SciTech Connect

    Ehrlich, R.

    1985-01-01

    Since the explosions of the first atomic bombs, a large literature has appeared on the effects and risks of nuclear war. The most widely quoted recent publications have concentrated on the impossibility of any meaningful survival after a superpower nuclear exchange. By contrast, Dr. Ehrlich tries to show both sides of the various arguments involved. As a result, he undoubtedly succeeds in his avowed intention of angering both hawks and doves. He offers a critical analysis of most considerations apposite to the current nuclear-weapon impasse, including the nature of current nuclear arms, the possibility of limited nuclear war, the short-term and long-term effects of nuclear weapons, the value of civil defense, the importance of public opinion, and the feasibility of arms control.

  11. Nuclear Models

    NASA Astrophysics Data System (ADS)

    Fossión, Rubén

    2010-09-01

    The atomic nucleus is a typical example of a many-body problem. On the one hand, the number of nucleons (protons and neutrons) that constitute the nucleus is too large to allow for exact calculations. On the other hand, the number of constituent particles is too small for the individual nuclear excitation states to be explained by statistical methods. Another problem, particular for the atomic nucleus, is that the nucleon-nucleon (n-n) interaction is not one of the fundamental forces of Nature, and is hard to put in a single closed equation. The nucleon-nucleon interaction also behaves differently between two free nucleons (bare interaction) and between two nucleons in the nuclear medium (dressed interaction). Because of the above reasons, specific nuclear many-body models have been devised of which each one sheds light on some selected aspects of nuclear structure. Only combining the viewpoints of different models, a global insight of the atomic nucleus can be gained. In this chapter, we revise the the Nuclear Shell Model as an example of the microscopic approach, and the Collective Model as an example of the geometric approach. Finally, we study the statistical properties of nuclear spectra, basing on symmetry principles, to find out whether there is quantum chaos in the atomic nucleus. All three major approaches have been rewarded with the Nobel Prize of Physics. In the text, we will stress how each approach introduces its own series of approximations to reduce the prohibitingly large number of degrees of freedom of the full many-body problem to a smaller manageable number of effective degrees of freedom.

  12. Nuclear Models

    SciTech Connect

    Fossion, Ruben

    2010-09-10

    The atomic nucleus is a typical example of a many-body problem. On the one hand, the number of nucleons (protons and neutrons) that constitute the nucleus is too large to allow for exact calculations. On the other hand, the number of constituent particles is too small for the individual nuclear excitation states to be explained by statistical methods. Another problem, particular for the atomic nucleus, is that the nucleon-nucleon (n-n) interaction is not one of the fundamental forces of Nature, and is hard to put in a single closed equation. The nucleon-nucleon interaction also behaves differently between two free nucleons (bare interaction) and between two nucleons in the nuclear medium (dressed interaction).Because of the above reasons, specific nuclear many-body models have been devised of which each one sheds light on some selected aspects of nuclear structure. Only combining the viewpoints of different models, a global insight of the atomic nucleus can be gained. In this chapter, we revise the the Nuclear Shell Model as an example of the microscopic approach, and the Collective Model as an example of the geometric approach. Finally, we study the statistical properties of nuclear spectra, basing on symmetry principles, to find out whether there is quantum chaos in the atomic nucleus. All three major approaches have been rewarded with the Nobel Prize of Physics. In the text, we will stress how each approach introduces its own series of approximations to reduce the prohibitingly large number of degrees of freedom of the full many-body problem to a smaller manageable number of effective degrees of freedom.

  13. Single molecule diffraction.

    PubMed

    Spence, J C H; Doak, R B

    2004-05-14

    For solving the atomic structure of organic molecules such as small proteins which are difficult to crystallize, the use of a jet of doped liquid helium droplets traversing a continuous high energy electron beam is proposed as a means of obtaining electron diffraction patterns (serial crystallography). Organic molecules (such as small proteins) within the droplet (and within a vitreous ice jacket) may be aligned by use of a polarized laser beam. Iterative methods for solving the phase problem are indicated. Comparisons with a related plan for pulsed x-ray diffraction from single proteins in a molecular beam are provided.

  14. DNA: An Extensible Molecule

    NASA Astrophysics Data System (ADS)

    Cluzel, Philippe; Lebrun, Anne; Heller, Christoph; Lavery, Richard; Viovy, Jean-Louis; Chatenay, Didier; Caron, Francois

    1996-02-01

    The force-displacement response of a single duplex DNA molecule was measured. The force saturates at a plateau around 70 piconewtons, which ends when the DNA has been stretched about 1.7 times its contour length. This behavior reveals a highly cooperative transition to a state here termed S-DNA. Addition of an intercalator suppresses this transition. Molecular modeling of the process also yields a force plateau and suggests a structure for the extended form. These results may shed light on biological processes involving DNA extension and open the route for mechanical studies on individual molecules in a previously unexplored range.

  15. Enzyme molecules as nanomotors.

    PubMed

    Sengupta, Samudra; Dey, Krishna K; Muddana, Hari S; Tabouillot, Tristan; Ibele, Michael E; Butler, Peter J; Sen, Ayusman

    2013-01-30

    Using fluorescence correlation spectroscopy, we show that the diffusive movements of catalase enzyme molecules increase in the presence of the substrate, hydrogen peroxide, in a concentration-dependent manner. Employing a microfluidic device to generate a substrate concentration gradient, we show that both catalase and urease enzyme molecules spread toward areas of higher substrate concentration, a form of chemotaxis at the molecular scale. Using glucose oxidase and glucose to generate a hydrogen peroxide gradient, we induce the migration of catalase toward glucose oxidase, thereby showing that chemically interconnected enzymes can be drawn together.

  16. Live CLEM imaging to analyze nuclear structures at high resolution.

    PubMed

    Haraguchi, Tokuko; Osakada, Hiroko; Koujin, Takako

    2015-01-01

    Fluorescence microscopy (FM) and electron microscopy (EM) are powerful tools for observing molecular components in cells. FM can provide temporal information about cellular proteins and structures in living cells. EM provides nanometer resolution images of cellular structures in fixed cells. We have combined FM and EM to develop a new method of correlative light and electron microscopy (CLEM), called "Live CLEM." In this method, the dynamic behavior of specific molecules of interest is first observed in living cells using fluorescence microscopy (FM) and then cellular structures in the same cell are observed using electron microscopy (EM). Following image acquisition, FM and EM images are compared to enable the fluorescent images to be correlated with the high-resolution images of cellular structures obtained using EM. As this method enables analysis of dynamic events involving specific molecules of interest in the context of specific cellular structures at high resolution, it is useful for the study of nuclear structures including nuclear bodies. Here we describe Live CLEM that can be applied to the study of nuclear structures in mammalian cells.

  17. How organic molecules can control electronic devices.

    PubMed

    Vilan, Ayelet; Cahen, David

    2002-01-01

    This article examines a somewhat counter-intuitive approach to molecular-based electronic devices. Control over the electronic energy levels at the surfaces of conventional semiconductors and metals is achieved by assembling on the solid surfaces, poorly organized, partial monolayers (MLs) of molecules instead of the more commonly used ideal ones. Once those surfaces become interfaces, these layers exert electrostatic rather than electrodynamic control over the resulting devices, based on both electrical monopole and dipole effects of the molecules. Thus electronic transport devices, incorporating molecules, can be constructed without current flow through the molecules. This is illustrated for a gallium arsenide (GaAs) sensor as well as for gold-silicon (Au-Si) and Au-GaAs diodes. Incorporating molecules into solid interfaces becomes possible, using a 'soft' electrical contacting procedure, so as not to damage the molecules. Because there are only a few molecular restrictions, this approach opens up possibilities for the use of more complex (including biologically active) molecules as it circumvents requirements for ideal MLs and for molecules that can tolerate actual electron transport through them.

  18. Nuclear age thinking

    SciTech Connect

    Depastas, A.N.

    1990-01-01

    According to the practicalist school, thinking emerges from activity and each human practice is giving food to its own distinctive kinds of perception, conduct, and perspective of the world. The author, while studying and describing developments after the commencement of the nuclear age in many fields of human behavior and knowledge, including the social sciences, particularly psychology and international politics, became an adherent to the practicalist philosophy when he perceived new relevant thoughts coming to his mind at the same time. Indeed writing is a learning experience. He has, therefore, systematically included these thoughts in the following pages and synoptically characterized them in the title: Nuclear Age Thinking. He considers this kind of thinking as automatic, conscious activity which is gradually influencing our choices and decisions. The author has reservations as regards Albert Einstein's saying that the unleashed power of the atom changed everything save our modes of thinking, because the uncontrollability of nuclear energy is apparently in the subconscious of mankind nowadays, influencing the development of a new mode of thinking, and that is the nuclear age thinking which is the subject of this book. Nuclear age thinking drives from the collective fear of extinction of life on earth due to this new power at man's disposal, and it is not only limited to the change in the conventional meaning of the words war and peace.

  19. Computation of free-molecular flow in nuclear materials

    NASA Astrophysics Data System (ADS)

    Casella, Andrew M.; Loyalka, Sudarshan K.; Hanson, Brady D.

    2009-11-01

    Generally, the transport of gases and vapors in nuclear materials is adequately described by the diffusion equation with an effective diffusion coefficient. There are instances however, in which the flow pathway can be so restrictive that the diffusion description has limitations. In general, molecular transport is governed by intermolecular forces and collisions (interactions between multiple gas/vapor molecules) and by molecule-surface interactions. However, if nano-scale pathways exist within these materials, as has been suggested, then molecular transport can be characterized as being in the free-molecular flow regime where intermolecular interactions can be ignored and flow is determined entirely by molecule-surface collisions. Our purpose in this investigation is to focus on free-molecular transport in fine capillaries of a range of shapes and to explore the effect of geometry on this transport. We have employed Monte Carlo techniques in our calculations, and for simple geometries we have benchmarked our results against some analytical and previously available results. We have used Mathematica ® which has exceptional built-in symbolic and graphical capabilities, permitting easy handling of complicated geometries and good visualization of the results. Our computations provide insights into the role of geometry in molecular transport in nuclear materials with narrow pathways for flows, and also will be useful in guiding computations that include intermolecular collisions and more realistic gas-surface collision operators.

  20. Nuclear and radiological Security: Introduction.

    SciTech Connect

    Miller, James Christopher

    2016-02-24

    Nuclear security includes the prevention and detection of, and response to, theft, sabotage, unauthorized access, illegal transfer, or other malicious acts involving nuclear or other radioactive substances or their associated facilities. The presentation begins by discussing the concept and its importance, then moves on to consider threats--insider threat, sabotage, diversion of materials--with considerable emphasis on the former. The intrusion at Pelindaba, South Africa, is described as a case study. The distinction between nuclear security and security of radiological and portable sources is clarified, and the international legal framework is touched upon. The paper concludes by discussing the responsibilities of the various entities involved in nuclear security.