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Sample records for energy nucleus nucleus

  1. High energy nucleus-nucleus collisions

    NASA Technical Reports Server (NTRS)

    Wosiek, B.

    1986-01-01

    Experimental results on high energy nucleus-nucleus interactions are presented. The data are discussed within the framework of standard super-position models and from the point-of-view of the possible formation of new states of matter in heavy ion collisions.

  2. Meson multiplicity versus energy in relativistic nucleus-nucleus collisions

    NASA Technical Reports Server (NTRS)

    Atwater, T. W.; Freier, P. S.

    1986-01-01

    A systematic study of meson multiplicity as a function of energy at energies up to 100 GeV/u in nucleus-nucleus collisions has been made, using cosmic-ray data in nuclear emulsion. The data are consistent with simple nucleon-nucleon superposition models. Multiplicity per interacting nucleon in AA collisions does not appear to differ significantly from pp collisions.

  3. Photoproduction of lepton pairs in proton-nucleus and nucleus-nucleus collisions at RHIC and LHC energies

    SciTech Connect

    Moreira, B. D.; Goncalves, V. P.; De Santana Amaral, J. T.

    2013-03-25

    In this contribution we study coherent interactions as a probe of the nonlinear effects in the Quantum Electrodynamics (QED). In particular, we study the multiphoton effects in the production of leptons pairs for proton-nucleus and nucleus-nucleus collisions for heavy nuclei. In the proton-nucleus we assume the ultrarelativistic proton as a source of photons and estimate the photoproduction of lepton pairs on nuclei at RHIC and LHC energies considering the multiphoton effects associated to multiple rescattering of the projectile photon on the proton of the nucleus. In nucleus - nucleus colllisions we consider the two nuclei as a source of photons. As each scattering contributes with a factor {alpha}Z to the cross section, this contribution must be taken into account for heavy nuclei. We consider the Coulomb corrections to calculate themultiple scatterings and estimate the total cross section for muon and tau pair production in proton-nucleus and nucleus-nucleus collisions at RHIC and LHC energies.

  4. Average transverse momentum and energy density in high-energy nucleus-nucleus collisions

    NASA Technical Reports Server (NTRS)

    Burnett, T. H.; Dake, S.; Fuki, M.; Gregory, J. C.; Hayashi, T.; Holynski, R.; Iwai, J.; Jones, W. V.; Jurak, A.; Lord, J. J.

    1986-01-01

    Emulsion chambers were used to measure the transverse momenta of photons or pi(0) mesons produced in high-energy cosmic-ray nucleus-nucleus collisions. A group of events having large average transverse momenta has been found which apparently exceeds the expected limiting values. Analysis of the events at early interaction times, of the order of 1 fm/c, indicates that the observed transverse momentum increases with both rapidity density and energy density.

  5. Finite nucleus effects on relativistic energy corrections

    NASA Technical Reports Server (NTRS)

    Dyall, Kenneth G.; Faegri, Knut, Jr.

    1993-01-01

    The effect of using a finite nucleus model in quantum-chemical calculations is examined. Relativistic corrections from the first order Foldy-Wouthuysen terms are affected indirectly by the change in wavefunction, but also directly as a result of revised expressions for the Darwin and spin-orbit terms due to the change in nuclear potential. A calculation for the Rn atom indicates that the mass-velocity and Darwin corrections are much more sensitive to the finite nucleus than the non-relativistic total energy, but that the total contribution for these two terms is quite stable provided the revised form of the Darwin term is used. The spin-orbit interaction is not greatly affected by the choice of nuclear model.

  6. Fermi-motion effect on the intermediate energy nucleus-nucleus collision

    NASA Astrophysics Data System (ADS)

    Fan, G. W.; Kong, W. Y.; Han, T. F.; Li, X. C.; Ma, J. B.; Sheng, Z. Q.; Shi, G. Z.; Tian, F.; Wang, J.; Zhang, C.

    2016-11-01

    The Glauber model is modified with the Fermi-motion effect in the calculation of elastic differential cross-sections and momentum distributions of a fragment from mother nucleus. Different reaction systems at low energies are calculated with the modified Glauber model. It is found that calculations including the Fermi-motion provide a better prescription relating the model to a proper nuclear density distribution by comparing with the experimental data. On the basis of the studies, the influence of the correction on the extracted nuclear radius is quantified. The results further confirm the importance of the Fermi-motion in the nucleus-nucleus collision reactions at low energies.

  7. Pion and Kaon Lab Frame Differential Cross Sections for Intermediate Energy Nucleus-Nucleus Collisions

    NASA Technical Reports Server (NTRS)

    Norbury, John W.; Blattnig, Steve R.

    2008-01-01

    Space radiation transport codes require accurate models for hadron production in intermediate energy nucleus-nucleus collisions. Codes require cross sections to be written in terms of lab frame variables and it is important to be able to verify models against experimental data in the lab frame. Several models are compared to lab frame data. It is found that models based on algebraic parameterizations are unable to describe intermediate energy differential cross section data. However, simple thermal model parameterizations, when appropriately transformed from the center of momentum to the lab frame, are able to account for the data.

  8. Low-energy antinucleon-nucleus interaction revisited

    NASA Astrophysics Data System (ADS)

    Friedman, E.

    2015-08-01

    Annihilation cross sections of antiprotons and antineutrons on the proton between 50 and 400 MeV/c show Coulomb focusing below 200 MeV/c and almost no charge-dependence above 200 MeV/c. Similar comparisons for heavier targets are not possible for lack of overlap between nuclear targets studied with and beams. Interpolating between -nucleus annihilation cross sections with the help of an optical potential to compare with -nucleus annihilation cross sections reveal unexpected features of Coulomb interactions in the latter. Direct comparisons between -nucleus and -nucleus annihilations at very low energies could be possible if cross sections are measured on the same targets and at the same energies as the available cross sections for . Such measurements may be feasible in the foreseeable future.

  9. Neutral current neutrino-nucleus interactions at high energies

    SciTech Connect

    Gay Ducati, M. B.; Machado, M. M.; Machado, M. V. T.

    2009-04-01

    We present a QCD analysis of the neutral current (NC) neutrino-nucleus interaction at the small-x region using the color dipole formalism. This phenomenological approach is quite successful in describing experimental results in deep inelastic ep scattering and charged current neutrino-nucleus interactions at high energies. We present theoretical predictions for the relevant structure functions and the corresponding implications for the total NC neutrino cross section. It is shown that at small x, the NC boson-nucleon cross section should exhibit the geometric scaling property that has important consequences for ultrahigh energy neutrino phenomenology.

  10. High-energy pion-nucleus scattering at LAMPF

    SciTech Connect

    Morris, C.L.

    1993-01-01

    Recent data obtained for pion-nucleus interactions above the [triangle](1232) is presented. The expected long mean-free path at pion energies above the [3,3] resonance is demonstrated in elastic scattering. Evidence for unexpected nuclear transparency for outgoing pions at resonance energies is presented. A new technique measuring virtual [triangle] components of the nuclear wave function is suggested.

  11. High-energy pion-nucleus scattering at LAMPF

    SciTech Connect

    Morris, C.L.

    1993-02-01

    Recent data obtained for pion-nucleus interactions above the {triangle}(1232) is presented. The expected long mean-free path at pion energies above the [3,3] resonance is demonstrated in elastic scattering. Evidence for unexpected nuclear transparency for outgoing pions at resonance energies is presented. A new technique measuring virtual {triangle} components of the nuclear wave function is suggested.

  12. Experimental studies of pion-nucleus interactions at intermediate energies

    SciTech Connect

    Not Available

    1991-12-31

    This report summarizes the work on experimental research in intermediate energy nuclear physics carried out at New Mexico State University in 1991 under a great from the US Department of Energy. Most of these studies have involved investigations of various pion-nucleus interactions. The work has been carried out both with the LAMPF accelerator at the Los Alamos National Laboratory and with the cyclotron at the Paul Scherrer Institute (PSI) near Zurich, Switzerland. Part of the experimental work involves measurements of new data on double-charge-exchange scattering, using facilities at LAMPF which we helped modify, and on pion absorption, using a new detector system at PSI that covers nearly the full solid-angle region which we helped construct. Other work involved preparation for future experiments using polarized nuclear targets and a new high-resolution spectrometer system for detecting {pi}{sup 0} mesons. We also presented several proposals for works to be done in future years, involving studies related to pi-mesonic atoms, fundamental pion-nucleon interactions, studies of the difference between charged and neutral pion interactions with the nucleon, studies of the isospin structure of pion-nucleus interactions, and pion scattering from polarized {sup 3}He targets. This work is aimed at improving our understanding of the pion-nucleon interaction, of the pion-nucleus interaction mechanism, and of nuclear structure.

  13. Multiple pion and kaon production in high energy nucleus-nucleus collisions: measurements versus specific models

    NASA Astrophysics Data System (ADS)

    Guptaroy, P.; de, Bh.; Bhattacharyya, S.; Bhattacharyya, D. P.

    The pion and kaon rapidity densities and the nature of kaon-pion ratios offer two very prominent and crucial physical observables on which modestly sufficient data for heavy nucleus collisions are available to date. In the light of two sets of models - one purely phenomenological and the other with a modest degree of a dynamical basis - we try to examine the state of agreement between calculations and experimental results obtainable from the past and the latest measurements. Impact and implications of all these would also finally be spelt out.

  14. Onset of deconfinement in nucleus-nucleus collisions

    SciTech Connect

    Gazdzicki, M.; Gorenstein, M. I.; Seyboth, P.

    2012-05-15

    The energy dependence of hadron production in relativistic nucleus-nucleus collisions reveals anomalies-the kink, horn, and step. They were predicted as signals of the deconfinement phase transition and observed by the NA49 Collaboration in central PbPb collisions at the CERN SPS. This indicates the onset of the deconfinement in nucleus-nucleus collisions at about 30 A GeV.

  15. Extended Glauber Model of Antiproton-Nucleus Annihilation for All Energies and Mass Numbers

    SciTech Connect

    Lee, Teck-Ghee; Wong, Cheuk-Yin

    2014-01-01

    Previous analytical formulas in the Glauber model for high-energy nucleus-nucleus collisions developed by Wong are utilized and extended to study Antiproton-nucleus annihilations for both high and low energies, after taking into account the effects of Coulomb and nuclear interactions, and the change of the antiproton momentum inside a nucleus. The extended analytical formulas capture the main features of the experimental antiproton-nucleus annihilation cross sections for all energies and mass numbers. At high antiproton energies, they exhibit the granular property for the lightest nuclei and the black-disk limit for the heavy nuclei. At low antiproton energies, they display the effect of the antiproton momentum increase due to the nuclear interaction for the light nuclei, and the effect of the magnification due to the attractive Coulomb interaction for the heavy nuclei.

  16. Effect of energy transfer from atomic electron shell to an α particle emitted by decaying nucleus

    NASA Astrophysics Data System (ADS)

    Igashov, S. Yu.; Tchuvil'sky, Yu. M.

    2016-12-01

    The process of energy transfer from the electron shell of an atom to an α particle propagating through the shell is formulated mathematically. Using the decay of the 226Ra nucleus as an example, it is demonstrated that this phenomenon increases the α-decay intensity in contrast with other known effects of similar type. Moreover, the α decay of the nucleus is more strongly affected by the energy transfer than by all other effects taken together.

  17. Momentum loss in proton-nucleus and nucleus-nucleus collisions

    NASA Technical Reports Server (NTRS)

    Khan, Ferdous; Townsend, Lawrence W.

    1993-01-01

    An optical model description, based on multiple scattering theory, of longitudinal momentum loss in proton-nucleus and nucleus-nucleus collisions is presented. The crucial role of the imaginary component of the nucleon-nucleon transition matrix in accounting for longitudinal momentum transfer is demonstrated. Results obtained with this model are compared with Intranuclear Cascade (INC) calculations, as well as with predictions from Vlasov-Uehling-Uhlenbeck (VUU) and quantum molecular dynamics (QMD) simulations. Comparisons are also made with experimental data where available. These indicate that the present model is adequate to account for longitudinal momentum transfer in both proton-nucleus and nucleus-nucleus collisions over a wide range of energies.

  18. On the photon production in nucleus-nucleus collisions at high energy

    NASA Astrophysics Data System (ADS)

    Tarasov, Y. A.; Antonenko, V. G.

    1995-03-01

    A modified Landau hydrodynamical model is applied to study hard thermal photon production in central heavy-ion collisions at LHC, RHIC and SPS energies. It is shown that the phase transition from quark-gluon plasma into hadrons in consequence of the thermodynamical expansion is close to the second order phase transition if a resonance production is taken into account. Hard direct photon emission is also investigated with consideration of nuclear shadowing effect on structure function of quarks and gluons. Also ππ photon background is investigated. It is demonstrated that at the LHC energy photon yield from the quark-gluon plasma in the photon transversal momentum k ⊥ range from 5 to 25 GeV/c exceeds both the background and the direct photon yield. This conclusion may be important for the quark-gluon plasma diagnostic aims. It is also shown that for the LHC energy the thermal photon yield in the present model essentially exceeds this yield obtained in the Bjorken scaling model.

  19. Difference in Energy Metabolism of Annulus Fibrosus and Nucleus Pulposus Cells of the Intervertebral Disc

    PubMed Central

    Salvatierra, Jessica Czamanski; Yuan, Tai Yi; Fernando, Hanan; Castillo, Andre; Gu, Wei Yong; Cheung, Herman S.; Huant, C.-Y. Charles

    2011-01-01

    Low back pain is associated with intervertebral disc degeneration. One of the main signs of degeneration is the inability to maintain extracellular matrix integrity. Extracellular matrix synthesis is closely related to production of adenosine triphosphate (i.e. energy) of the cells. The intervertebral disc is composed of two major anatomical regions: annulus fibrosus and nucleus pulposus, which are structurally and compositionally different, indicating that their cellular metabolisms may also be distinct. The objective of this study was to investigate energy metabolism of annulus fibrosus and nucleus pulposus cells with and without dynamic compression, and examine differences between the two cell types. Porcine annulus and nucleus tissues were harvested and enzymatically digested. Cells were isolated and embedded into agarose constructs. Dynamically loaded samples were subjected to a sinusoidal displacement at 2 Hz and 15% strain for 4 h. Energy metabolism of cells was analyzed by measuring adenosine triphosphate content and release, glucose consumption, and lactate/nitric oxide production. A comparison of those measurements between annulus and nucleus cells was conducted. Annulus and nucleus cells exhibited different metabolic pathways. Nucleus cells had higher adenosine triphosphate content with and without dynamic loading, while annulus cells had higher lactate production and glucose consumption. Compression increased adenosine triphosphate release from both cell types and increased energy production of annulus cells. Dynamic loading affected energy metabolism of intervertebral disc cells, with the effect being greater in annulus cells. PMID:21625336

  20. Pion yields and the nature of kaon-pion ratios in high energy nucleus-nucleus collisons: models versus measurements

    NASA Astrophysics Data System (ADS)

    Bhattacharyya, S.; De, B.; Guptaroy, P.

    2001-08-01

    The pion densities and the nature of kaon-pion ratios offer two very prominent and crucial physical observables on which sufficient data for heavy nucleus collisions, to date, are available. In the light of two models - one purely phenomenological and the other with a sound dynamical basis - we would try to examine here the state of agreement between calculations and experimental results obtainable from the past and the latest measurements. Impact and implications of all these would also finally be spelt out.

  1. Low-energy neutrino-nucleus interactions and beta-beam neutrino

    SciTech Connect

    Jachowicz, N.; Pandey, V.

    2015-05-15

    We present an overview of neutrino-nucleus scattering at low energies with cross sections obtained within a continuum random phase approximation (CRPA) formalism. We highlight potential applications of beta-beam neutrino experiments for neutrino astrophysics. Our calculations are compared with MiniBooNe data at intermediate energies.

  2. The Nucleus Introduced

    PubMed Central

    Pederson, Thoru

    2011-01-01

    Now is an opportune moment to address the confluence of cell biological form and function that is the nucleus. Its arrival is especially timely because the recognition that the nucleus is extremely dynamic has now been solidly established as a paradigm shift over the past two decades, and also because we now see on the horizon numerous ways in which organization itself, including gene location and possibly self-organizing bodies, underlies nuclear functions. PMID:20660024

  3. Sensitivity of cross sections for elastic nucleus-nucleus scattering to halo nucleus density distributions

    SciTech Connect

    Alkhazov, G. D.; Sarantsev, V. V.

    2012-12-15

    In order to clear up the sensitivity of the nucleus-nucleus scattering to the nuclear matter distributions in exotic halo nuclei, we have calculated differential cross sections for elastic scattering of the {sup 6}He and {sup 11}Li nuclei on several nuclear targets at the energy of 0.8 GeV/nucleon with different assumed nuclear density distributions in {sup 6}He and {sup 11}Li.

  4. Low-energy theorems for pion photoproduction from nuclei and pion-nucleus coupling constants

    SciTech Connect

    Radutskii, G.M.; Serdyutskii, V.A.

    1982-10-01

    New low-energy theorems for pion photoproduction in light nuclei are derived using a model that allows one to extract all the information contained in the current algebra and the CVC and PCAC hypotheses. From the comparison with the experimental total cross sections for threshold photoproduction of charged pions on the nuclei /sup 6/Li, /sup 12/C, and /sup 14/N, the values of the pion-nucleus coupling constants are obtained and the magnitude of the electric quadrupole moment of the /sup 12/N nucleus is predicted.

  5. Determination of primary energy in nucleus-nucleus collisions and the high P(sub)T tail of alpha-particles

    NASA Technical Reports Server (NTRS)

    Freier, P. S.; Atwater, T. W.

    1985-01-01

    A determination of primary energy is required in order to study the energy dependence of meson multiplicity in A-A collisions in cosmic rays. Various procedures which estimate the energy of a primary nucleus from its interaction were investigated. An average of two methods were used, one using the pions and wounded protons and the other using spectator protons and alpha particles. The high P sub T tail observed for Z = 2 fragments requires a modification of the latter method.

  6. Development of global medium-energy nucleon-nucleus optical model potentials

    SciTech Connect

    Madland, D.G.; Sierk, A.J.

    1997-08-01

    The authors report on the development of new global optical model potentials for nucleon-nucleus scattering at medium energies. Using both Schroedinger and Dirac scattering formalisms, the goal is to construct a physically realistic optical potential describing nucleon-nucleus elastic scattering observables for a projectile energy range of (perhaps) 20 meV to (perhaps) 2 GeV and a target mass range of 16 to 209, excluding regions of strong nuclear deformation. They use a phenomenological approach guided by conclusions from recent microscopic studies. The experimental database consists largely of proton-nucleus elastic differential cross sections, analyzing powers, spin-rotation functions, and total reaction cross sections, and neutron-nucleus total cross sections. They will use this database in a nonlinear least-squares adjustment of optical model parameters in both relativistic equivalent Schroedinger (including relativistic kinematics) and Dirac (second-order reduction) formalisms. Isospin will be introduced through the standard Lane model and a relativistic generalization of that model.

  7. Kaon-nucleus scattering

    NASA Technical Reports Server (NTRS)

    Hong, Byungsik; Maung, Khin Maung; Wilson, John W.; Buck, Warren W.

    1989-01-01

    The derivations of the Lippmann-Schwinger equation and Watson multiple scattering are given. A simple optical potential is found to be the first term of that series. The number density distribution models of the nucleus, harmonic well, and Woods-Saxon are used without t-matrix taken from the scattering experiments. The parameterized two-body inputs, which are kaon-nucleon total cross sections, elastic slope parameters, and the ratio of the real to the imaginary part of the forward elastic scattering amplitude, are presented. The eikonal approximation was chosen as our solution method to estimate the total and absorptive cross sections for the kaon-nucleus scattering.

  8. Kaon-nucleus scattering

    NASA Technical Reports Server (NTRS)

    Hong, Byungsik; Buck, Warren W.; Maung, Khin M.

    1989-01-01

    Two kinds of number density distributions of the nucleus, harmonic well and Woods-Saxon models, are used with the t-matrix that is taken from the scattering experiments to find a simple optical potential. The parameterized two body inputs, which are kaon-nucleon total cross sections, elastic slope parameters, and the ratio of the real to imaginary part of the forward elastic scattering amplitude, are shown. The eikonal approximation was chosen as the solution method to estimate the total and absorptive cross sections for the kaon-nucleus scattering.

  9. Experimental studies of pion-nucleus and nucleon-nucleus interactions at intermediate energies. Progress report, April 1, 1991--March 31, 1994

    SciTech Connect

    1993-09-30

    This report summarizes the work on experimental research in intermediate energy nuclear physics carried out at New Mexico State University in 1991-94 under a grant from the U.S. Department of Energy. Most of these studies involved investigations of various pion-nucleus interactions and nucleon-nucleus charge-exchange reactions. The work was carried out with the LAMPF accelerator at the Los Alamos National Laboratory and the cyclotrons at the Paul Scherrer Institute (PSI) near Zurich, Switzerland, at Indiana University (IUCF), and at TRIUMF in Vancouver, Canada, as collaborative efforts among several laboratories and universities. We have also worked on plans and preparations for new experiments involving studies of the quark structure of nucleons and nuclei, which would be carried out at Fermilab (FNAL), near Chicago, and at the HERA facility at the DESY laboratory in Hamburg, Germany. The NMSU personnel included two faculty members, five postdoctoral research associates, nine graduate students, and one undergraduate student.

  10. Color Fluctuations in High Energy Hadronand Photon-Nucleus Collisions

    NASA Astrophysics Data System (ADS)

    Frankfurt, Leonid; Strikman, Mark

    We explain that coherence of high energy QED and QCD processes implies existence of new kind of phenomena which are beyond a framework based on Regge poles (cuts). New phenomena emerge as the consequence of compositeness of the bound states and the Lorentz slowing down of interaction. We focus on the color fluctuations phenomena predicted earlier for pA collisions within QCD and recent evidence for this phenomenon from pA LHC run, significant modification of nuclear shadowing phenomenon in the diffractive photoproduction of vector mesons observed recently in the ultra peripheral collisions at LHC. We outlined briefly general properties of color fluctuations phenomena and perspectives of future studies of this phenomenon in electron (photon) collisions with nuclei.

  11. Pion- and proton-nucleus interactions at intermediate energy

    SciTech Connect

    Dehnhard, D.

    1992-12-01

    We report on scattering and reaction experiments on light nuclei using the [pi]-meson and proton beams from the Los Alamos Meson Physics Facility (LAMPF) and the Indiana University Cyclotron Facility (IUCF). Differential cross sections, cross section asymmetries, and angular correlation functions have been measured in order to test models of the reaction mechanism and of nuclear structure. At LAMPF we have measured asymmetries for pion scattering from polarized [sup 13]C which are uniquely sensitive to the isoscalar spin density. In order to determine details of the reaction mechanism, we have obtained approval for a scattering experiment on polarized [sup 3]He for which the nuclear structure is very well known. We have completed data taking for two studies of elastic scattering of [pi][sup +] from [sup 6]Li and [sup l3]C. The detailed differential cross sections from these experiments will be used to constrain theoretical analyses of previous polarization experiments done at the Pierre-Scherrer-Institute (PSI) and at LAMPF. We have analyzed [pi]-triton coincidence events from the [sup 4]He([pi],[pi][prime] t)p reaction and have found evidence for direct triton knockout from [sup 4]He. We have extended these angular correlation measurements to higher energies and to [sup 2]H and [sup 3]He targets. At IUCF we have performed the first [sup 4]He(p,n) experiment at intermediate energies, T[sub p] = 100, 147, and 200 MeV, in a search for previously reported narrow states in [sup 4]Li of widths of [approx] 1 MeV. Within the statistics of the data we have found no evidence for such narrow structures.

  12. Pion- and proton-nucleus interactions at intermediate energy

    SciTech Connect

    Dehnhard, D.

    1992-02-01

    {pi}-meson and proton beams from the Los Alamos Meson Physics Facility (LAMPF) and the Indiana University Cyclotron Facility (IUCF) were used in scattering and reaction experiments on atomic nuclei. The experimental data allow tests of models of the reaction mechanism and of nuclear structure. For example, the asymmetries observed in a pion scattering experiment on polarized {sup 13}C nuclei were found to contain unique information on the isoscalar spin density. However, further experiments on polarized nuclei of simpler structure are needed to provide the data for a thorough analysis of the reaction mechanism. For this reason a pion scattering experiment on a polarized {sup 3}He target is planned and a high-resolution study on {sup 6}Li({pi},{pi}{prime}) will be done. An analysis of {pi}-triton coincidence events from the {sup 4}He({pi},{pi}{prime}t)p reaction yielded evidence for direct triton knock-out from {sup 4}He. This work will be continued at higher incident pion energies. Additional work on the {sup 4}He(p,n) reaction at IUCF is planned to determine the isovector strength in mass-4 nuclei and the level parameters of {sup 4}Li.

  13. Experimental studies of pion-nucleus interactions at intermediate energies. Annual progress report

    SciTech Connect

    Not Available

    1991-12-31

    This report summarizes the work on experimental research in intermediate energy nuclear physics carried out at New Mexico State University in 1991 under a great from the US Department of Energy. Most of these studies have involved investigations of various pion-nucleus interactions. The work has been carried out both with the LAMPF accelerator at the Los Alamos National Laboratory and with the cyclotron at the Paul Scherrer Institute (PSI) near Zurich, Switzerland. Part of the experimental work involves measurements of new data on double-charge-exchange scattering, using facilities at LAMPF which we helped modify, and on pion absorption, using a new detector system at PSI that covers nearly the full solid-angle region which we helped construct. Other work involved preparation for future experiments using polarized nuclear targets and a new high-resolution spectrometer system for detecting {pi}{sup 0} mesons. We also presented several proposals for works to be done in future years, involving studies related to pi-mesonic atoms, fundamental pion-nucleon interactions, studies of the difference between charged and neutral pion interactions with the nucleon, studies of the isospin structure of pion-nucleus interactions, and pion scattering from polarized {sup 3}He targets. This work is aimed at improving our understanding of the pion-nucleon interaction, of the pion-nucleus interaction mechanism, and of nuclear structure.

  14. Dynamical nucleus-nucleus potential at short distances

    SciTech Connect

    Jiang Yongying; Wang Ning; Li Zhuxia; Scheid, Werner

    2010-04-15

    The dynamical nucleus-nucleus potentials for fusion reactions {sup 40}Ca+{sup 40}Ca, {sup 48}Ca+{sup 208}Pb, and {sup 126}Sn+{sup 130}Te are studied with the improved quantum molecular dynamics model together with the extended Thomas-Fermi approximation for the kinetic energies of nuclei. The obtained fusion barrier for {sup 40}Ca+{sup 40}Ca is in good agreement with the extracted fusion barrier from the measured fusion excitation function, and the depths of the fusion pockets are close to the results of time-dependent Hartree-Fock calculations. The energy dependence of the fusion barrier is also investigated. The fusion pocket becomes shallow for a heavy fusion system and almost disappears for heavy nearly symmetric systems, and the obtained potential at short distances is higher than the adiabatic potential.

  15. Azimuthal correlation and collective behavior in nucleus-nucleus collisions

    SciTech Connect

    Mali, P.; Mukhopadhyay, A. Sarkar, S.; Singh, G.

    2015-03-15

    Various flow effects of nuclear and hadronic origin are investigated in nucleus-nucleus collisions. Nuclear emulsion data collected from {sup 84}Kr + Ag/Br interaction at an incident energy of 1.52 GeV per nucleon and from {sup 28}Si + Ag/Br interaction at an incident energy of 14.5 GeV per nucleon are used in the investigation. The transverse momentum distribution and the flow angle analysis show that collective behavior, like a bounce-off effect of the projectile spectators and a sidesplash effect of the target spectators, are present in our event samples. From an azimuthal angle analysis of the data we also see a direct flow of the projectile fragments and of the produced charged particles. On the other hand, for both data samples the target fragments exhibit a reverse flow, while the projectile fragments exhibit an elliptic flow. Relevant flow parameters are measured.

  16. Neutrino-nucleus interactions

    SciTech Connect

    Gallagher, H.; Garvey, G.; Zeller, G.P.; /Fermilab

    2011-01-01

    The study of neutrino oscillations has necessitated a new generation of neutrino experiments that are exploring neutrino-nuclear scattering processes. We focus in particular on charged-current quasi-elastic scattering, a particularly important channel that has been extensively investigated both in the bubble-chamber era and by current experiments. Recent results have led to theoretical reexamination of this process. We review the standard picture of quasi-elastic scattering as developed in electron scattering, review and discuss experimental results, and discuss additional nuclear effects such as exchange currents and short-range correlations that may play a significant role in neutrino-nucleus scattering.

  17. Reality of comet nucleus.

    NASA Technical Reports Server (NTRS)

    Lyttleton, R. A.

    1972-01-01

    The prime problem of a comet mission must be to settle whether the cometary nucleus has an actual tangible material existence, or whether it arises from some optical effect present only at times within comets. The absence of any large particles in a comet seems to be demonstrated by certain meteor showers. A feature that would seem to indicate that a comet consists primarily of a swarm of particles is that the coma in general contracts as the comet approaches the sun, roughly in proportion within the distance, and then expands again as it recedes.

  18. Nucleus from string theory

    NASA Astrophysics Data System (ADS)

    Hashimoto, Koji; Morita, Takeshi

    2011-08-01

    In generic holographic QCD, we find that baryons are bound to form a nucleus, and that its radius obeys the empirically-known mass-number (A) dependence r∝A1/3 for large A. Our result is robust, since we use only a generic property of D-brane actions in string theory. We also show that nucleons are bound completely in a finite volume. Furthermore, employing a concrete holographic model (derived by Hashimoto, Iizuka, and Yi, describing a multibaryon system in the Sakai-Sugimoto model), the nuclear radius is evaluated as O(1)×A1/3[fm], which is consistent with experiments.

  19. Higgs-boson production in nucleus-nucleus collisions

    NASA Technical Reports Server (NTRS)

    Norbury, J. W.; Townsend, L. W. (Principal Investigator)

    1990-01-01

    Cross-section calculations are presented for the production of intermediate-mass Higgs bosons produced in ultrarelativistic nucleus-nucleus collisions via two-photon fusion. The calculations are performed in position space using Baur's method for folding together the Weizsacker-Williams virtual-photon spectra of the two colliding nuclei. It is found that two-photon fusion in nucleus-nucleus collisions is a plausible way of finding intermediate-mass Higgs bosons at the Superconducting Super Collider or the CERN Large Hadron Collider.

  20. Higgs-Boson Production in Nucleus-Nucleus Collisions

    NASA Technical Reports Server (NTRS)

    Norbury, John W.

    1992-01-01

    Cross section calculations are presented for the production of intermediate-mass Higgs bosons produced in ultrarelativistic nucleus-nucleus collisions via two photon fusion. The calculations are performed in position space using Baur's method for folding together the Weizsacker-Williams virtual-photon spectra of the two colliding nuclei. It is found that two photon fusion in nucleus-nucleus collisions is a plausible way of finding intermediate-mass Higgs bosons at the Superconducting Super Collider or the CERN Large Hadron Collider.

  1. Experimental studies of nucleon-nucleon and pion-nucleus interactions at intermediate energies

    SciTech Connect

    Not Available

    1990-10-01

    This report summarizes the work on experimental research in intermediate energy nuclear and particle physics carried out by New Mexico State University in 1988--91. Most of these studies have involved investigations of neutron-proton and pion-nucleus interactions. The neutron-proton research is part of a program of studies of interactions between polarized nucleons that we have been involved with for more than ten years. Its purpose has been to help complete the determination of the full set of ten complex nucleon-nucleon amplitudes at energies up to 800 MeV, as well as to continue investigating the possibility of the existence of dibaryon resonances. The give complex isospin-one amplitudes have been fairly well determined, partly as a result of this work. Our work in this period has involved measurements and analysis of data on elastic scattering and total cross sections for polarized neutrons on polarized protons. The pion-nucleus research continues our studies of this interaction in regions where it has not been well explored. One set of experiments includes studies of pion elastic and double-charge-exchange scattering at energies between 300 and 550 MeV, where our data is unique. Another involves elastic and single-charge-exchange scattering of pions from polarized nuclear targets, a new field of research which will give the first extensive set of information on spin-dependent pion-nucleus amplitudes. Still another involves the first set of detailed studies of the kinematic correlations among particles emitted following pion absorption in nuclei.

  2. Networking the nucleus

    PubMed Central

    Rajapakse, Indika; Scalzo, David; Tapscott, Stephen J; Kosak, Steven T; Groudine, Mark

    2010-01-01

    The nuclei of differentiating cells exhibit several fundamental principles of self-organization. They are composed of many dynamical units connected physically and functionally to each other—a complex network—and the different parts of the system are mutually adapted and produce a characteristic end state. A unique cell-specific signature emerges over time from complex interactions among constituent elements that delineate coordinate gene expression and chromosome topology. Each element itself consists of many interacting components, all dynamical in nature. Self-organizing systems can be simplified while retaining complex information using approaches that examine the relationship between elements, such as spatial relationships and transcriptional information. These relationships can be represented using well-defined networks. We hypothesize that during the process of differentiation, networks within the cell nucleus rewire according to simple rules, from which a higher level of order emerges. Studying the interaction within and among networks provides a useful framework for investigating the complex organization and dynamic function of the nucleus. PMID:20664641

  3. Electromagnetic probes of a pure-glue initial state in nucleus-nucleus collisions at energies available at the CERN Large Hadron Collider

    NASA Astrophysics Data System (ADS)

    Vovchenko, V.; Karpenko, Iu. A.; Gorenstein, M. I.; Satarov, L. M.; Mishustin, I. N.; Kämpfer, B.; Stoecker, H.

    2016-08-01

    Partonic matter produced in the early stage of ultrarelativistic nucleus-nucleus collisions is assumed to be composed mainly of gluons, and quarks and antiquarks are produced at later times. To study the implications of such a scenario, the dynamical evolution of a chemically nonequilibrated system is described by ideal (2+1)-dimensional hydrodynamics with a time dependent (anti)quark fugacity. The equation of state interpolates linearly between the lattice data for the pure gluonic matter and the lattice data for the chemically equilibrated quark-gluon plasma. The spectra and elliptic flows of thermal dileptons and photons are calculated for central Pb+Pb collisions at the CERN Large Hadron Collider energy of √{sN N}=2.76 TeV. We test the sensitivity of the results to the choice of equilibration time, including also the case where the complete chemical equilibrium of partons is reached already at the initial stage. It is shown that a suppression of quarks at early times leads to a significant reduction of the yield of the thermal dileptons, but only to a rather modest suppression of the pT distribution of direct photons. It is demonstrated that an enhancement of photon and dilepton elliptic flows might serve as a promising signature of the pure-glue initial state.

  4. BFKL Pomeron calculus: solution to equations for nucleus-nucleus scattering in the saturation domain

    NASA Astrophysics Data System (ADS)

    Contreras, Carlos; Levin, Eugene; Meneses, Rodrigo

    2013-04-01

    In this paper we solve the equation for nucleus-nucleus scattering in the BFKL Pomeron calculus, suggested by Braun [1-3]. We find these solutions analytically at high energies as well as numerically in the entire region of energies inside the saturation region. The semi-classical approximation is used to select out the infinite set of the parasite solutions. The nucleus-nucleus cross sections at high energy are estimated and compared with the Glauber-Gribov approach. It turns out that the exact formula gives the estimates that are very close to the ones based on Glauber-Gribov formula which is important for the practical applications.

  5. Checkerboard Theory of the Nucleus.

    NASA Astrophysics Data System (ADS)

    Lach, Theodore

    2006-04-01

    The Checker Board Model (CBM) is a 2D model of the nucleus that proposes that the synchronization of the 2 outer rotating quarks in the nucleons accounts for magnetic moment of the nucleons and that the magnetic flux from the nucleons couples (weaves) into the 2D checker board array structures and this magnetic coupling in addition to electrostatic forces of the rotating and stationary quarks accounts for the apparent strong nuclear force. The symmetry of the He nucleus helps explain why this 2D structure is so stable. This model explain the mass of the proton and neutron, along with their magnetic moments and their absolute and relative sizes in terms of the above structure and predict the masses of two newly proposed quarks ^(1): the ``up'' and the ``dn'' quarks. Since the masses of the ``up'' and ``dn'' quark determined by the CBM (237.31 MeV and 42.392 MeV respectively) did not fit within the standard model as candidates for u and d, a new model (New Physics) had to be invented. This new particle physics model predicts that nature has 5 generations not 3. (1). T.M. Lach, Checkerboard Structure of the Nucleus, Infinite Energy, Vol. 5, issue 30, (2000). (2). T.M. Lach, Masses of the Sub-Nuclear Particles, nucl-th/0008026, @http://xxx.lanl.gov/

  6. The intercalatus nucleus of Staderini.

    PubMed

    Cascella, Marco

    2016-01-01

    Rutilio Staderini was one of the leading Italian anatomists of the twentieth century, together with some scientists, such as Giulio Chiarugi, Giovanni Vitali, and others. He was also a member of a new generation of anatomists. They had continued the tradition of the most famous Italian scientists, which started from the Renaissance up until the nineteenth century. Although he carried out important studies of neuroanatomy and comparative anatomy, as well as embryology, his name is rarely remembered by most medical historians. His name is linked to the nucleus he discovered: the Staderini nucleus or intercalated nucleus, a collection of nerve cells in the medulla oblongata located lateral to the hypoglossal nucleus. This article focuses on the biography of the neuroanatomist as well as the nucleus that carries his name and his other research, especially on comparative anatomy and embryology.

  7. Development of the Hamiltonian molecular dynamics (HMD) model: A first-principles, relativistic description of nucleus-nucleus interactions at medium energy

    NASA Astrophysics Data System (ADS)

    Zapp, Edward Neal

    Simulation of energetic, colliding nuclear systems at energies between 100 AMeV and 5 AGeV has utility in fields as diverse as the design and construction of fundamental particle physics experiments, patient treatment by radiation exposure, and in the protection of astronaut crews from the risks of exposure to natural radiation sources during spaceflight. Descriptions of these colliding systems which are derived from theoretical principles are necessary in order to provide confidence in describing systems outside the scope of existing data, which is sparse. The system size and velocity dictate descriptions which include both special relativistic and quantum effects, and the currently incomplete state of understanding with respect to the basic processes at work within nuclear matter dictate that any description will exist at some level of approximation. Models commonly found in the literature employ approximations to theory which lead to simulation results which demonstrate departure from fundamental physical principles, most notably conservation of system energy. The HMD (Hamiltonian Molecular Dynamics) mode is developed as a phase-space description of colliding nuclear system on the level of hadrons, inclusive of the necessary quantum and relativistic elements. Evaluation of model simulations shows that the HMD model shows the necessary conservations throughout system simulation. HMD model predictions are compared to both the RQMD (Relativistic Quantum Molecular Dynamics) and JQMD (Jaeri-Quantum Molecular Dynamics) codes, both commonly employed for the purpose of simulating nucleus-nucleus collisions. Comparison is also provided between all three codes and measurement. The HMD model is shown to perform well in light of both measurement and model calculation, while providing for a physically self-consistent description of the system throughout.

  8. Low-energy {omega} ({yields}{pi}{sup 0}{gamma}) meson photoproduction in the nucleus

    SciTech Connect

    Das, Swapan

    2011-06-15

    The {pi}{sup 0{gamma}} invariant mass distribution spectra in the ({gamma},{pi}{sup 0{gamma}}) reaction were measured by the TAPS/ELSA Collaboration to look for the hadron parameters of the {omega} meson in the Nb nucleus. We study the mechanism for this reaction, where we consider that the elementary reaction in the Nb nucleus proceeds as {gamma}N{yields}{omega}N;{omega}{yields}{pi}{sup 0}{gamma}. The {omega}-meson photoproduction amplitude for this reaction is extracted from the measured four-momentum transfer distribution in the {gamma}p{yields}{omega}p reaction. The propagation of the {omega} meson and the distorted wave function for the {pi}{sup 0} meson in the final state are described by the eikonal form. The {omega} and {pi}{sup 0} mesons' nucleus optical potentials, appearing in the {omega} meson propagator and {pi}{sup 0} meson distorted wave function respectively, are estimated using the t{rho} approximation. The effects of pair correlation and color transparency are also studied. The calculated results do not show medium modification for the {omega} meson produced in the nucleus for momentum greater than 200 MeV. It occurs because the {omega} meson predominantly decays outside the nucleus. The dependence of the cross section on the final-state interaction is also investigated. The broadening of the {omega}-meson mass distribution spectra is shown to occur due to the large resolution width associated with the detector used in the experiment.

  9. Photo nuclear energy loss term for muon-nucleus interactions based on xi scaling model of QCD

    NASA Technical Reports Server (NTRS)

    Roychoudhury, R.

    1985-01-01

    Extensive air showers (EMC) experiments discovered a significant deviation of the ratio of structure functions of iron and deuteron from unity. It was established that the quark parton distribution in nuclei are different from the corresponding distribution in the nucleus. It was examined whether these results have an effect on the calculation of photo nucleus energy loss term for muon-nucleus nuclear interaction. Though the EMC and SLAC data were restricted to rather large q sq region it is expected that the derivation would persist even in the low q sq domain. For the ratio of iron and deuteron structure function a rather naive least square fit of the form R(x) = a + bx was taken and it is assumed that the formula is valid for the whole q sq region the absence of any knowledge of R(x) for small q sq.

  10. Specific energy from Auger and conversion electrons of 131I, 188Re-anti-CD20 to a lymphocyte's nucleus

    NASA Astrophysics Data System (ADS)

    Torres-García, E.; Carrillo-Cazares, T. A.

    2011-01-01

    The typical radionuclides used to label anti-CD20 in the treatment of non-Hodgkin's lymphoma are 90Y, 131I, and 188Re, with the emission of beta particles, Auger electrons, and conversion electrons for the latter two. The aim of the present work was to calculate the contribution of high linear energy transfer radiation as Auger electrons (AE) and conversion electrons (CE) of 131I and 188Re-anti-CD20 to mean specific energy into the cell nucleus by Monte Carlo simulation (MCS), so as to infer therapeutic effectiveness on a dosimetric basis. MCS was used to quantify the frequency-mean specific energy into the cell nucleus, where the cell was modeled by two concentric spheres, considering two cell models. The results showed that 10% and 33% of the mean-specific energies (z¯) per disintegration imparted to the cell nucleus for both geometries are due to AE and CE; on the other hand, if the hit of AE and CE occurs, the contribution to (z¯) is about 64% and 86% for 131I and 188Re, respectively. According to the amount of specific energy from AE and CE into the cell nucleus by positive event, they can cause catastrophic effects in the nuclear DNA in the treatment of non-Hodgkin's lymphoma with 131I, 188Re-anti-CD20.

  11. Surface albedo of cometary nucleus

    NASA Astrophysics Data System (ADS)

    Mukai, T.; Mukai, S.

    A variation of the albedo on the illuminated disk of a comet nucleus is estimated, taking into account the multiple reflection of incident light due to small scale roughness. The dependences of the average albedo over the illuminated disk on the degree of roughness and on the complex refractive index of the surface materials are examined. The variation estimates are compared with measurements of the nucleus albedo of Comet Halley (Reitsema et al., 1987).

  12. Intermediate Energy Proton Nucleus Scattering from CALCIUM-40, ZIRCONIUM-90 and LEAD-208.

    NASA Astrophysics Data System (ADS)

    Lee, Lawrence

    In recent years, there has been much interest in studying proton-nucleus scattering at intermediate bombarding energies. We focus on two main themes in this thesis. Firstly, we examine the importance of measuring scattering observables out to high momentum transfers where they become sensitive to the matter distribution in the interior of the nucleus. Here, we find that nuclear medium and exchange effects are needed, especially at lower proton kinetic energies (~ 200 MeV). Secondly, we focus on the remarkable and systematic agreement between experimental data and theory when a consistent microscopic approach is used. As part of our study, we have made high momentum transfer measurements at TRIUMF for proton elastic and inelastic scattering from ^{40} Ca, ^{90}Zr and ^{208}Pb. Differential cross sections and analyzing powers are presented for proton kinetic energies of 200, 362 and 400 MeV out to a maximum momentum transfer of q~ 4.8 fm^{-1}, well above the typical limit of ~2.5 fm ^{-1}. Our elastic data are analyzed with a nonrelativistic microscopic optical model based on the Hamburg density -dependent two-body interaction (Ge83a) and on the Decharge and Gogny (De87) theoretical ground states, and involve no adjustable parameters. The calculations show surprisingly good agreement with data as it follows the cross section through typically 9 orders of magnitude and reproduces the oscillations in the analyzing power out to high q for a number of target nuclei and at various bombarding energies. The success of the elastic calculations also suggests that the theoretical model(s) are sufficiently well understood that nuclear structure problems can now be investigated. We study this aspect mainly through the low-lying natural -parity 3^- and 5^ - transitions. The inelastic data are analyzed with distorted-wave Born approximation calculations using the same nonrelativistic density-dependent interaction to drive the transition, the same optical model potential to distort

  13. Asymptotic formula far from nucleus for exchange energy density in Hartree-Fock theory of closed-shell atoms

    NASA Astrophysics Data System (ADS)

    March, N. H.

    In Hartree-Fock theory, the exchange energy density can be expressed solely in terms of the first-order density matrix. Far from the nucleus of a closed-shell atom, idem potency of the density matrix yields the exchange energy density as the magnitude of the Coulomb energy e2/r times the electron density ρ. Thus two lengths enter the asymptotic form in contrast to ρ-1/3 alone of local-density theory.

  14. Control of energy homeostasis by insulin and leptin: targeting the arcuate nucleus and beyond.

    PubMed

    Könner, A Christine; Klöckener, Tim; Brüning, Jens C

    2009-07-14

    As the obesity epidemic, diabetes mellitus type 2, and associated comorbidities show no signs of abating, large efforts have been put into a better understanding of the homeostatic control mechanisms involved in regulation of body weight and energy homeostasis. For decades, the hypothalamic arcuate nucleus (ARC), which integrates peripheral signals and modulates appetite and metabolism, has been the focus of investigation. Besides these basic homeostatic circuits, food palatability and reward are thought to be major factors involved in the regulation of food intake. Highly palatable food is easily available, and is ingested even when there is no metabolic need for it. Thus, overriding of the homeostatic control systems by the cognitive, rewarding, social, and emotional aspects of palatable food may contribute to the obesity epidemic. This review aims to provide an updated view, how insulin and leptin as signals originating from the periphery of the body and communicating energy availability to the CNS act not only on ARC neurons, but also directly control the activity of neuronal circuits in control of food-associated reward mechanisms.

  15. J/ψ production and suppression in high-energy proton-nucleus collisions

    SciTech Connect

    Ma, Yan -Qing; Venugopalan, Raju; Zhang, Hong -Fei

    2015-10-02

    In this study, we apply a color glass condensate+nonrelativistic QCD (CGC+NRQCD) framework to compute J/ψ production in deuteron-nucleus collisions at RHIC and proton-nucleus collisions at the LHC. Our results match smoothly at high p⊥ to a next-to-leading order perturbative QCD+NRQCD computation. Excellent agreement is obtained for p⊥ spectra at the RHIC and LHC for central and forward rapidities, as well as for the normalized ratio RpA of these results to spectra in proton-proton collisions. In particular, we observe that the RpA data are strongly bounded by our computations of the same for each of the individual NRQCD channels; this result provides strong evidence that our description is robust against uncertainties in initial conditions and hadronization mechanisms.

  16. J/ψ production and suppression in high-energy proton-nucleus collisions

    DOE PAGES

    Ma, Yan -Qing; Venugopalan, Raju; Zhang, Hong -Fei

    2015-10-02

    In this study, we apply a color glass condensate+nonrelativistic QCD (CGC+NRQCD) framework to compute J/ψ production in deuteron-nucleus collisions at RHIC and proton-nucleus collisions at the LHC. Our results match smoothly at high p⊥ to a next-to-leading order perturbative QCD+NRQCD computation. Excellent agreement is obtained for p⊥ spectra at the RHIC and LHC for central and forward rapidities, as well as for the normalized ratio RpA of these results to spectra in proton-proton collisions. In particular, we observe that the RpA data are strongly bounded by our computations of the same for each of the individual NRQCD channels; this resultmore » provides strong evidence that our description is robust against uncertainties in initial conditions and hadronization mechanisms.« less

  17. Experimental studies of pion-nucleus interactions at intermediate energies. Annual progress report

    SciTech Connect

    Not Available

    1992-12-31

    This report summarizes investigations of various pion-nucleus interactions and nucleon-nucleus charge-exchange reactions. The work was carried out with the LAMPF accelerator at the Los Alamos National Laboratory and the cyclotrons at the Paul Scherrer Institute (PSI) near Zurich, Switzerland, and at Indiana University (IUCF), as a collaborative effort among several laboratories and universities. The experimental activity at LAMPF involved measurements of new data on pion double-charge-exchange scattering, some initial work on a new Neutral Meson Spectrometer system, a search for deeply-bound pionic atoms, measurements of elastic scattering, and studies of the (n,p) reaction on various nuclei. At PSI measurements of pion quasielastic scattering were carried out, with detection of the recoil proton. Work on the analysis of data from a previous experiment at PSI on pion absorption in nuclei was continued. This experiment involved using a detector system that covered nearly the full solid angle.

  18. Elastic alpha scattering experiments and the alpha-nucleus optical potential at low energies

    SciTech Connect

    Mohr, P.; Kiss, G.G.; Fülöp, Zs.; Galaviz, D.; Gyürky, Gy.; Somorjai, E.

    2013-11-15

    High precision angular distribution data of (α,α) elastic scattering are presented for the nuclei {sup 89}Y, {sup 92}Mo, {sup 106,110,116}Cd, {sup 112,124}Sn, and {sup 144}Sm at energies around the Coulomb barrier. Such data with small experimental uncertainties over the full angular range (20–170°) are the indispensable prerequisite for the extraction of local optical potentials and for the determination of the total reaction cross section σ{sub reac}. A systematic fitting procedure was applied to the experimental scattering data presented to obtain comprehensive local potential parameter sets that are composed of a real folding potential and an imaginary potential of Woods–Saxon surface type. The potential parameters obtained were used in turn to construct a new systematic α-nucleus potential with very few parameters. Although this new potential cannot reproduce the angular distributions with the same small deviations as the local potential, the new potential is able to predict the total reaction cross sections for all cases under study.

  19. Formin' actin in the nucleus.

    PubMed

    Baarlink, Christian; Grosse, Robert

    2014-01-01

    Many if not most proteins can, under certain conditions, change cellular compartments, such as, for example, shuttling from the cytoplasm to the nucleus. Thus, many proteins may exert functions in various and very different subcellular locations, depending on the signaling context. A large amount of actin regulatory proteins has been detected in the mammalian cell nucleus, although their potential roles are much debated and are just beginning to emerge. Recently, members of the formin family of actin nucleators were also reported to dynamically localize to the nuclear environment. Here we discuss our findings that specific diaphanous-related formins can promote nuclear actin assembly in a signal-dependent manner.

  20. Functionalized active-nucleus complex sensor

    DOEpatents

    Pines, Alexander; Wemmer, David E.; Spence, Megan; Rubin, Seth

    2003-11-25

    A functionalized active-nucleus complex sensor that selectively associates with one or more target species, and a method for assaying and screening for one or a plurality of target species utilizing one or a plurality of functionalized active-nucleus complexes with at least two of the functionalized active-nucleus complexes having an attraction affinity to different corresponding target species. The functionalized active-nucleus complex has an active-nucleus and a targeting carrier. The method involves functionalizing an active-nucleus, for each functionalized active-nucleus complex, by incorporating the active-nucleus into a macromolucular or molecular complex that is capable of binding one of the target species and then bringing the macromolecular or molecular complexes into contact with the target species and detecting the occurrence of or change in a nuclear magnetic resonance signal from each of the active-nuclei in each of the functionalized active-nucleus complexes.

  1. Higgs and Particle Production in Nucleus-Nucleus Collisions

    NASA Astrophysics Data System (ADS)

    Liu, Zhe

    We apply a diagrammatic approach to study Higgs boson, a color-neutral heavy particle, pro- duction in nucleus-nucleus collisions in the saturation framework without quantum evolution. We assume the strong coupling constant much smaller than one. Due to the heavy mass and colorless nature of Higgs particle, final state interactions are absent in our calculation. In order to treat the two nuclei dynamically symmetric, we use the Coulomb gauge which gives the appropriate light cone gauge for each nucleus. To further eliminate initial state interactions we choose specific prescriptions in the light cone propagators. We start the calculation from only two nucleons in each nucleus and then demonstrate how to generalize the calculation to higher orders diagrammatically. We simplify the diagrams by the Slavnov-Taylor-Ward identities. The resulting cross section is factorized into a product of two Weizsacker-Williams gluon distributions of the two nuclei when the transverse momentum of the produced scalar particle is around the saturation momentum. To our knowledge this is the first process where an exact analytic formula has been formed for a physical process, involving momenta on the order of the saturation momentum, in nucleus-nucleus collisions in the quasi-classical approximation. Since we have performed the calculation in an unconventional gauge choice, we further confirm our results in Feynman gauge where the Weizsacker-Williams gluon distribution is interpreted as a transverse momentum broadening of a hard gluons traversing a nuclear medium. The transverse momentum factorization manifests itself in light cone gauge but not so clearly in Feynman gauge. In saturation physics there are two different unintegrated gluon distributions usually encountered in the literature: the Weizsacker-Williams gluon distribution and the dipole gluon distribution. The first gluon distribution is constructed by solving classical Yang-Mills equation of motion in the Mc

  2. Static versus energy-dependent nucleus-nucleus potential for description of sub-barrier fusion dynamics of {}_{8}^{16}O+{}^{112,116,120}\\!\\!\\!\\!\\!\\!{}_{50}Sn reactions

    NASA Astrophysics Data System (ADS)

    Manjeet Singh, Gautam

    2015-11-01

    The static and energy-dependent nucleus-nucleus potentials are simultaneously used along with the Wong formula for exploration of fusion dynamics of {}816O+{}112,116,120{}50Sn reactions. The role of internal structure degrees of freedom of colliding pairs, such as inelastic surface vibrations, are examined within the context of coupled channel calculations performed using the code CCFULL. Theoretical calculations based on the static Woods-Saxon potential along with the one-dimensional Wong formula fail to address the fusion data of {}816O+{}112,116,120{}50Sn reactions. Such discrepancies can be removed if one uses couplings to internal structure degrees of freedom of colliding nuclei. However, the energy-dependent Woods-Saxon potential model (EDWSP model) accurately describes the sub-barrier fusion enhancement of {}816O+{}112,116,120{}50Sn reactions. Therefore, in sub-barrier fusion dynamics, energy dependence in the nucleus-nucleus potential governs barrier modification effects in a closely similar way to that of the coupled channel approach. Supported by Dr. D. S. Kothari Post-Doctoral Fellowship Scheme sponsored by University Grants Commission (UGC), New Delhi, India

  3. Single nucleon emission in relativistic nucleus-nucleus reactions

    NASA Technical Reports Server (NTRS)

    Norbury, John W.; Townsend, Lawrence W.

    1992-01-01

    Significant discrepancies between theory and experiment have previously been noted for nucleon emission via electromagnetic processes in relativistic nucleus-nucleus collisions. The present work investigates the hypothesis that these discrepancies have arisen due to uncertainties about how to deduce the experimental electromagnetic cross section from the total measured cross section. An optical-model calculation of single neutron removal is added to electromagnetic cross sections and compared to the total experimental cross sections. Good agreement is found thereby resolving some of the earlier noted discrepancies. A detailed comparison to the recent work of Benesh, Cook, and Vary is made for both the impact parameter and the nuclear cross section. Good agreement is obtained giving an independent confirmation of the parameterized formulas developed by those authors.

  4. Analysis of relativistic nucleus-nucleus interactions in emulsion chambers

    NASA Technical Reports Server (NTRS)

    Mcguire, Stephen C.

    1987-01-01

    The development of a computer-assisted method is reported for the determination of the angular distribution data for secondary particles produced in relativistic nucleus-nucleus collisions in emulsions. The method is applied to emulsion detectors that were placed in a constant, uniform magnetic field and exposed to beams of 60 and 200 GeV/nucleon O-16 ions at the Super Proton Synchrotron (SPS) of the European Center for Nuclear Research (CERN). Linear regression analysis is used to determine the azimuthal and polar emission angles from measured track coordinate data. The software, written in BASIC, is designed to be machine independent, and adaptable to an automated system for acquiring the track coordinates. The fitting algorithm is deterministic, and takes into account the experimental uncertainty in the measured points. Further, a procedure for using the track data to estimate the linear momenta of the charged particles observed in the detectors is included.

  5. Nucleon-nucleus interactions from JACEE

    NASA Technical Reports Server (NTRS)

    Burnett, T. H.; Dake, S.; Fuki, M.; Gregory, J. C.; Hayashi, T.; Holynski, R.; Iwai, J.; Jones, W. V.; Jurak, A.; Lord, J. J.

    1985-01-01

    Results on hadron-nucleus interactions from the Japanese-American Cooperation Emulsion Experiment experiment are presented. Angular distributions for charged particles, and angular and transverse momentum spectra for photons have been measured for a sample of events with sigma epsilon sub gamma. Results on central rapidity density and transverse energy flow are discussed.

  6. Hummingbird Comet Nucleus Analysis Mission

    NASA Technical Reports Server (NTRS)

    Kojiro, Daniel; Carle, Glenn C.; Lasher, Larry E.

    2000-01-01

    Hummingbird is a highly focused scientific mission, proposed to NASA s Discovery Program, designed to address the highest priority questions in cometary science-that of the chemical composition of the cometary nucleus. After rendezvous with the comet, Hummingbird would first methodically image and map the comet, then collect and analyze dust, ice and gases from the cometary atmosphere to enrich characterization of the comet and support landing site selection. Then, like its namesake, Hummingbird would carefully descend to a pre-selected surface site obtaining a high-resolution image, gather a surface material sample, acquire surface temperature and then immediately return to orbit for detailed chemical and elemental analyses followed by a high resolution post-sampling image of the site. Hummingbird s analytical laboratory contains instrumentation for a comprehensive molecular and elemental analysis of the cometary nucleus as well as an innovative surface sample acquisition device.

  7. Classifiers for centrality determination in proton-nucleus and nucleus-nucleus collisions

    NASA Astrophysics Data System (ADS)

    Altsybeev, Igor; Kovalenko, Vladimir

    2017-03-01

    Centrality, as a geometrical property of the collision, is crucial for the physical interpretation of nucleus-nucleus and proton-nucleus experimental data. However, it cannot be directly accessed in event-by-event data analysis. Common methods for centrality estimation in A-A and p-A collisions usually rely on a single detector (either on the signal in zero-degree calorimeters or on the multiplicity in some semi-central rapidity range). In the present work, we made an attempt to develop an approach for centrality determination that is based on machine-learning techniques and utilizes information from several detector subsystems simultaneously. Different event classifiers are suggested and evaluated for their selectivity power in terms of the number of nucleons-participants and the impact parameter of the collision. Finer centrality resolution may allow to reduce impact from so-called volume fluctuations on physical observables being studied in heavy-ion experiments like ALICE at the LHC and fixed target experiment NA61/SHINE on SPS.

  8. Exceptionally bright, compact starburst nucleus

    SciTech Connect

    Margon, B.; Anderson, S.F.; Mateo, M.; Fich, M.; Massey, P.

    1988-11-01

    Observations are reported of a remarkably bright (V about 13) starburst nucleus, 0833 + 652, which has been detected at radio, infrared, optical, ultraviolet, and X-ray wavelengths. Despite an observed flux at each of these wavelengths which is comparable to that of NGC 7714, often considered the 'prototypical' example of the starburst phenomenon, 0833 + 652 appears to be a previously uncataloged object. Its ease of detectability throughout the electromagnetic spectrum should make it useful for a variety of problems in the study of compact emission-line galaxies. 30 references.

  9. Nucleus morphology of Comet Halley

    NASA Technical Reports Server (NTRS)

    Reitsema, H. J.; Delamere, W. A.; Huebner, W. F.; Keller, H. U.; Schmidt, W. K. H.; Wilhelm, K.; Schmidt, H. U.; Whipple, Fred L.

    1986-01-01

    Images obtained by the Halley multicolor camera were used to determine the projected size and shape of the nucleus. The location of the terminator and numerous surface features were determined. There is good correlation between the brightest surface features and the dust jets; however, many bright features are seen which are not associated with jets. Most of the observed features are circular and appear to be related to surface elevation. The angularity of the terminator gives an indication of the three-dimensional structure of the face which was observed.

  10. Validity of the relativistic impulse approximation for elastic proton-nucleus scattering at energies lower than 200 MeV

    SciTech Connect

    Li, Z. P.; Hillhouse, G. C.; Meng, J.

    2008-07-15

    We present the first study to examine the validity of the relativistic impulse approximation (RIA) for describing elastic proton-nucleus scattering at incident laboratory kinetic energies lower than 200 MeV. For simplicity we choose a {sup 208}Pb target, which is a spin-saturated spherical nucleus for which reliable nuclear structure models exist. Microscopic scalar and vector optical potentials are generated by folding invariant scalar and vector scattering nucleon-nucleon (NN) amplitudes, based on our recently developed relativistic meson-exchange model, with Lorentz scalar and vector densities resulting from the accurately calibrated PK1 relativistic mean field model of nuclear structure. It is seen that phenomenological Pauli blocking (PB) effects and density-dependent corrections to {sigma}N and {omega}N meson-nucleon coupling constants modify the RIA microscopic scalar and vector optical potentials so as to provide a consistent and quantitative description of all elastic scattering observables, namely, total reaction cross sections, differential cross sections, analyzing powers and spin rotation functions. In particular, the effect of PB becomes more significant at energies lower than 200 MeV, whereas phenomenological density-dependent corrections to the NN interaction also play an increasingly important role at energies lower than 100 MeV.

  11. Observation of direct hadronic pairs in nucleus-nucleus collisions in JACEE emulsion chambers

    NASA Technical Reports Server (NTRS)

    Burnett, T. H.; Dake, S.; Fuki, M.; Gregory, J. C.; Hayashi, T.; Hayashi, T.; Holynski, R.; Iwai, J.; Jones, W. V.; Jurak, A.

    1985-01-01

    In a number of high energy ( or = 1 TeV/amu) nucleus-nucleus collisions observed in Japanese-American Cooperative Emulsion Experiment (JACEE) emulsion chambers, nonrandom spatial association of produced charged particles, mostly hadronic pairs, are observed. Similar narrow pairs are observed in about 100 events at much low energy (20 to 60 GeV/amu). Analysis shows that 30 to 50% of Pair abundances are understood by the Hambury-Brown-Twiss effect, and the remainder seems to require other explanations.

  12. Core-nucleus distortation in hypernuclei

    SciTech Connect

    Bodmer, A.R.; Usmani, Q.N.

    1995-08-01

    We are completing a study of the effects of the spherical distortion of the {open_quotes}core{close_quotes} nucleus by the {Lambda} in a hypernucleus. The response of the core was determined by an appropriately chosen energy-density functional which depends, in particular, on the nuclear compressibility. The forcing action of the A is determined by the nuclear density dependence of the {Lambda} binding in nuclear matter which is obtained from our work on the {Lambda} single-particle energies. Because of the strongly repulsive {Lambda}NN forces, this {Lambda} binding {open_quotes}saturates{close_quotes} at a density close to the central density of nuclei, and results in a reduced core-nucleus distortion much less than would otherwise be obtained. The effects of the core distortion then turn out to be very small even for quite light hypernuclei. This result justifies the assumption that spherical core nuclei are effectively undistorted in a hypernucleus.

  13. The Confined Hydrogen Atom with a Moving Nucleus

    ERIC Educational Resources Information Center

    Fernandez, Francisco M.

    2010-01-01

    We study the hydrogen atom confined to a spherical box with impenetrable walls but, unlike earlier pedagogical articles on the subject, we assume that the nucleus also moves. We obtain the ground-state energy approximately by means of first-order perturbation theory and show that it is greater than that for the case in which the nucleus is clamped…

  14. Pygmy dipole response in 238U nucleus

    NASA Astrophysics Data System (ADS)

    Guliyev, Ekber; Kuliev, Ali Akbar; Quliyev, Huseynqulu

    2017-02-01

    The presence of the El pygmy dipole resonance (PDR) in the actinide nucleus 238U was shown via QRPA. Below the particle threshold energy, 24 excitation states were calculated. The calculations, is demonstrating the presence of a PDR with evidence for K splitting. The calculations further suggest that the PDR in 238U is predominantly K=0. The obtained results show universality of the PDR in atomic nuclei.

  15. Nuclear mean field and double-folding model of the nucleus-nucleus optical potential

    NASA Astrophysics Data System (ADS)

    Khoa, Dao T.; Phuc, Nguyen Hoang; Loan, Doan Thi; Loc, Bui Minh

    2016-09-01

    Realistic density dependent CDM3Yn versions of the M3Y interaction have been used in an extended Hartree-Fock (HF) calculation of nuclear matter (NM), with the nucleon single-particle potential determined from the total NM energy based on the Hugenholtz-van Hove theorem that gives rise naturally to a rearrangement term (RT). Using the RT of the single-nucleon potential obtained exactly at different NM densities, the density and energy dependence of the CDM3Yn interactions was modified to account properly for both the RT and observed energy dependence of the nucleon optical potential. Based on a local density approximation, the double-folding model of the nucleus-nucleus optical potential has been extended to take into account consistently the rearrangement effect and energy dependence of the nuclear mean-field potential, using the modified CDM3Yn interactions. The extended double-folding model was applied to study the elastic 12C+12C and 16O+12C scattering at the refractive energies, where the Airy structure of the nuclear rainbow has been well established. The RT was found to affect significantly the real nucleus-nucleus optical potential at small internuclear distances, giving a potential strength close to that implied by the realistic optical model description of the Airy oscillation.

  16. Theoretical predictions for the nucleus 296118

    NASA Astrophysics Data System (ADS)

    Sobiczewski, A.

    2016-11-01

    Theoretical predictions for the α -decay chain of the nucleus 296118 are performed. The synthesis of this nucleus is being attempted in experiments running in Dubna. The α -decay energies Qα, and the α -decay and spontaneous-fission half-lives, Tα and Tsf, are studied. The analysis of the α decay is based on a phenomenological model using only three parameters. The calculations are performed in nine variants using masses obtained within nine nuclear-mass models describing masses of the heaviest nuclei. The experimental Qα energies, known from earlier experiments for the potential daughter, 292Lv, and grand-daughter, 288Fl, nuclei are reproduced with an average of the absolute values of the discrepancies: from 0.13 to 1.52 MeV within the considered variants. Measured half-lives Tα are reconstructed within average ratios: from 1.7 to 1054. Within all variants considered, the half-life Tα of the nucleus 296118 is obtained larger than needed (around 1 μ s ) for its observation.

  17. NEW CLASS OF VERY HIGH ENERGY {gamma}-RAY EMITTERS: RADIO-DARK MINI SHELLS SURROUNDING ACTIVE GALACTIC NUCLEUS JETS

    SciTech Connect

    Kino, Motoki; Kawakatu, Nozomu; Orienti, Monica

    2013-02-20

    We explore non-thermal emission from a shocked interstellar medium, which is identified as an expanding shell, driven by a relativistic jet in active galactic nuclei (AGNs). In this work, we particularly focus on parsec-scale size mini shells surrounding mini radio lobes. From the radio to X-ray band, the mini radio lobe emission dominates the faint emission from the mini shell. On the other hand, we find that inverse-Compton (IC) emission from the shell can overwhelm the associated lobe emission at the very high energy (VHE; E > 100 GeV) {gamma}-ray range, because energy densities of synchrotron photons from the lobe and/or soft photons from the AGN nucleus are large and IC scattering works effectively. The predicted IC emission from nearby mini shells can be detected with the Cherenkov Telescope Array and they are potentially a new class of VHE {gamma}-ray emitters.

  18. PI3K in the ventromedial hypothalamic nucleus mediates estrogenic actions on energy expenditure in female mice

    PubMed Central

    Saito, Kenji; He, Yanlin; Yang, Yongjie; Zhu, Liangru; Wang, Chunmei; Xu, Pingwen; Hinton, Antentor Othrell; Yan, Xiaofeng; Zhao, Jean; Fukuda, Makoto; Tong, Qingchun; Clegg, Deborah J.; Xu, Yong

    2016-01-01

    Estrogens act in the ventromedial hypothalamic nucleus (VMH) to regulate body weight homeostasis. However, the molecular mechanisms underlying these estrogenic effects are unknown. We show that activation of estrogen receptor-α (ERα) stimulates neural firing of VMH neurons expressing ERα, and these effects are blocked with intracellular application of a pharmacological inhibitor of the phosphatidyl inositol 3-kinase (PI3K). Further, we demonstrated that mice with genetic inhibition of PI3K activity in VMH neurons showed a sexual dimorphic obese phenotype, with only female mutants being affected. In addition, inhibition of VMH PI3K activity blocked effects of 17β-estradiol to stimulate energy expenditure, but did not affect estrogen-induced anorexia. Collectively, our results indicate that PI3K activity in VMH neurons plays a physiologically relevant role in mediating estrogenic actions on energy expenditure in females. PMID:26988598

  19. Projections from the central amygdaloid nucleus to the precuneiform nucleus in the mouse.

    PubMed

    Liang, Huazheng; Watson, Charles; Paxinos, George

    2015-01-01

    The mouse precuneiform nucleus has been proposed as the midbrain locomotion center, a function ascribed to its caudal neighbor, cuneiform nucleus, in the rat, cat and other species. The present study investigated the projections from the central amygdaloid nucleus to the precuneiform nucleus in the mouse using retrograde tracer injections (fluoro-gold) into the precuneiform nucleus and anterograde tracer injections (biotinylated dextran amine) into the central amygdaloid nucleus. The entire central amygdaloid nucleus except the rostral pole had retrogradely labeled neurons, especially in the middle portion where labeled neurons were densely packed. Anterogradely labeled amygdaloid fibers approached the precuneiform nucleus from the area ventrolateral to it and terminated in the entire precuneiform nucleus. Labeled fibers were also found in laminae 5 and 6 in the upper cervical cord on the ipsilateral side. The present study is the first demonstration of projections from the central amygdaloid nucleus to the precuneiform nucleus. This projection may underpin the role of the precuneiform nucleus in the modulation of the cardiovascular activity.

  20. Actomyosin contractility rotates the cell nucleus.

    PubMed

    Kumar, Abhishek; Maitra, Ananyo; Sumit, Madhuresh; Ramaswamy, Sriram; Shivashankar, G V

    2014-01-21

    The cell nucleus functions amidst active cytoskeletal filaments, but its response to their contractile stresses is largely unexplored. We study the dynamics of the nuclei of single fibroblasts, with cell migration suppressed by plating onto micro-fabricated patterns. We find the nucleus undergoes noisy but coherent rotational motion. We account for this observation through a hydrodynamic approach, treating the nucleus as a highly viscous inclusion residing in a less viscous fluid of orientable filaments endowed with active stresses. Lowering actin contractility selectively by introducing blebbistatin at low concentrations drastically reduced the speed and coherence of the angular motion of the nucleus. Time-lapse imaging of actin revealed a correlated hydrodynamic flow around the nucleus, with profile and magnitude consistent with the results of our theoretical approach. Coherent intracellular flows and consequent nuclear rotation thus appear to be an intrinsic property of cells.

  1. System-size and centrality dependence of charged kaon and pion production in nucleus-nucleus collisions at 40A GeV and 158A GeV beam energy

    NASA Astrophysics Data System (ADS)

    Anticic, T.; Baatar, B.; Barna, D.; Bartke, J.; Beck, H.; Betev, L.; Białkowska, H.; Blume, C.; Bogusz, M.; Boimska, B.; Book, J.; Botje, M.; Bunčić, P.; Cetner, T.; Christakoglou, P.; Chung, P.; Chvala, O.; Cramer, J. G.; Dinkelaker, P.; Eckardt, V.; Fodor, Z.; Foka, P.; Friese, V.; Gaździcki, M.; Grebieszkow, K.; Höhne, C.; Kadija, K.; Karev, A.; Kliemant, M.; Kolesnikov, V. I.; Kollegger, T.; Kowalski, M.; Kresan, D.; Laszlo, A.; Lacey, R.; van Leeuwen, M.; Lungwitz, B.; Mackowiak, M.; Makariev, M.; Malakhov, A. I.; Mateev, M.; Melkumov, G. L.; Mitrovski, M.; Mrówczyński, St.; Nicolic, V.; Pálla, G.; Panagiotou, A. D.; Peryt, W.; Pluta, J.; Prindle, D.; Pühlhofer, F.; Renfordt, R.; Roland, C.; Roland, G.; Rybczyński, M.; Rybicki, A.; Sandoval, A.; Schmitz, N.; Schuster, T.; Seyboth, P.; Siklér, F.; Skrzypczak, E.; Slodkowski, M.; Stefanek, G.; Stock, R.; Ströbele, H.; Susa, T.; Szuba, M.; Utvić, M.; Varga, D.; Vassiliou, M.; Veres, G. I.; Vesztergombi, G.; Vranić, D.; Włodarczyk, Z.; Wojtaszek-Szwarc, A.

    2012-11-01

    Measurements of charged pion and kaon production are presented in centrality selected Pb+Pb collisions at 40A GeV and 158A GeV beam energy as well as in semicentral C+C and Si+Si interactions at 40A GeV. Transverse mass spectra, rapidity spectra, and total yields are determined as a function of centrality. The system-size and centrality dependence of relative strangeness production in nucleus-nucleus collisions at 40A GeV and 158A GeV beam energy are derived from the data presented here and from published data for C+C and Si+Si collisions at 158A GeV beam energy. At both energies a steep increase with centrality is observed for small systems followed by a weak rise or even saturation for higher centralities. This behavior is compared to calculations using transport models (ultra-relativistic quantum molecular dynamics and hadron-string dynamics), a percolation model, and the core-corona approach.

  2. Music and the nucleus accumbens.

    PubMed

    Mavridis, Ioannis N

    2015-03-01

    Music is a universal feature of human societies over time, mainly because it allows expression and regulation of strong emotions, thus influencing moods and evoking pleasure. The nucleus accumbens (NA), the most important pleasure center of the human brain (dominates the reward system), is the 'king of neurosciences' and dopamine (DA) can be rightfully considered as its 'crown' due to the fundamental role that this neurotransmitter plays in the brain's reward system. Purpose of this article was to review the existing literature regarding the relation between music and the NA. Studies have shown that reward value for music can be coded by activity levels in the NA, whose functional connectivity with auditory and frontal areas increases as a function of increasing musical reward. Listening to music strongly modulates activity in a network of mesolimbic structures involved in reward processing including the NA. The functional connectivity between brain regions mediating reward, autonomic and cognitive processing provides insight into understanding why listening to music is one of the most rewarding and pleasurable human experiences. Musical stimuli can significantly increase extracellular DA levels in the NA. NA DA and serotonin were found significantly higher in animals exposed to music. Finally, passive listening to unfamiliar although liked music showed activations in the NA.

  3. PI3K in the ventromedial hypothalamic nucleus mediates estrogenic actions on energy expenditure in female mice

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Estrogens act in the ventromedial hypothalamic nucleus (VMH) to regulate body weight homeostasis. However, the molecular mechanisms underlying these estrogenic effects are unknown. We show that activation of estrogen receptor-a (ERa) stimulates neural firing of VMH neurons expressing ERa, and these ...

  4. Interactions and low-energy collisions between an alkali ion and an alkali atom of a different nucleus

    NASA Astrophysics Data System (ADS)

    Rakshit, Arpita; Ghanmi, Chedli; Berriche, Hamid; Deb, Bimalendu

    2016-05-01

    We study theoretically interaction potentials and low-energy collisions between different alkali atoms and alkali ions. Specifically, we consider systems such as X + {{{Y}}}+, where X({{{Y}}}+) is either Li(Cs+) or Cs(Li+), Na(Cs+) or Cs(Na+) and Li(Rb+) or Rb(Li+). We calculate the molecular potentials of the ground and first two excited states of these three systems using a pseudopotential method and compare our results with those obtained by others. We derive ground-state scattering wave functions and analyze the cold collisional properties of these systems for a wide range of energies. We find that, in order to get convergent results for the total scattering cross sections for energies of the order 1 K, one needs to take into account at least 60 partial waves. The low-energy scattering properties calculated in this paper may serve as a precursor for experimental exploration of quantum collisions between an alkali atom and an alkali ion of a different nucleus.

  5. Quarkonium-nucleus bound states from lattice QCD

    SciTech Connect

    Beane, S.  R.; Chang, E.; Cohen, S.  D.; Detmold, W.; Lin, H. -W.; Orginos, K.; Parreño, A.; Savage, M.  J.

    2015-06-11

    Quarkonium-nucleus systems are composed of two interacting hadronic states without common valence quarks, which interact primarily through multi-gluon exchanges, realizing a color van der Waals force. We present lattice QCD calculations of the interactions of strange and charm quarkonia with light nuclei. Both the strangeonium-nucleus and charmonium-nucleus systems are found to be relatively deeply bound when the masses of the three light quarks are set equal to that of the physical strange quark. Extrapolation of these results to the physical light-quark masses suggests that the binding energy of charmonium to nuclear matter is B < 40 MeV.

  6. A search for ϕ meson nucleus bound state using antiproton annihilation on nucleus

    NASA Astrophysics Data System (ADS)

    Ohnishi, H.; Bühler, P.; Cargnelli, M.; Curceanu, C.; Guaraldo, C.; Hartmann, O.; Hicks, K.; Iwasaki, M.; Ishiwatari, T.; Kienle, P.; Marton, J.; Muto, R.; Naruki, M.; Niiyama, M.; Noumi, H.; Okada, S.; Vidal, A. Romero; Sakaguchi, A.; Sakuma, F.; Sawada, S.; Sirghi, D.; Sirghi, F.; Suzuki, K.; Tsukada, K.; Doce, O. Vazquez; Widmann, E.; Yokkaichi, S.; Zmeskal, J.

    The mass shift of the vector mesons in nuclei is known to be a powerful tool for investigating the mechanism of generating hadron mass from the QCD vacuum. The mechanism is known to be the spontaneous breaking of chiral symmetry. In 2007, KEK-PS E325 experiment reported about 3.4 % mass reduction of the ϕ meson in medium-heavy nuclei (Cu). This result is possibly one of the indications of the partial restoration of chiral symmetry in nuclei, however, unfortunately it is hard to make strong conclusions from the data. One of the ways to conclude the strength of the ϕ meson mass shift in nuclei will be by trying to produce only slowly moving ϕ mesons where the maximum nuclear matter effect can be probed. The observed mass reduction of the ϕ meson in the nucleus can be translated as the existence of an attractive force between ϕ meson and nucleus. Thus, one of the extreme conditions that can be achieved in the laboratory is indeed the formation of a ϕ-nucleus bound state, where the ϕ meson is "trapped" in the nucleus. The purpose of the experiment is to search for a ϕ-nucleus bound state and measure the binding energy of the system. We will demonstrate that a completely background-free missing-mass spectrum can be obtained efficiently by (bar{p}, φ) spectroscopy together with K + Λ tagging, using the primary reaction channel bar{p} p rightarrow φ φ. This paper gives an overview of the physics motivation and the detector concept, and explains the direction of the initial research and development effort.

  7. A search for ϕ meson nucleus bound state using antiproton annihilation on nucleus

    NASA Astrophysics Data System (ADS)

    Ohnishi, H.; Bühler, P.; Cargnelli, M.; Curceanu, C.; Guaraldo, C.; Hartmann, O.; Hicks, K.; Iwasaki, M.; Ishiwatari, T.; Kienle, P.; Marton, J.; Muto, R.; Naruki, M.; Niiyama, M.; Noumi, H.; Okada, S.; Vidal, A. Romero; Sakaguchi, A.; Sakuma, F.; Sawada, S.; Sirghi, D.; Sirghi, F.; Suzuki, K.; Tsukada, K.; Doce, O. Vazquez; Widmann, E.; Yokkaichi, S.; Zmeskal, J.

    2012-12-01

    The mass shift of the vector mesons in nuclei is known to be a powerful tool for investigating the mechanism of generating hadron mass from the QCD vacuum. The mechanism is known to be the spontaneous breaking of chiral symmetry. In 2007, KEK-PS E325 experiment reported about 3.4 % mass reduction of the ϕ meson in medium-heavy nuclei (Cu). This result is possibly one of the indications of the partial restoration of chiral symmetry in nuclei, however, unfortunately it is hard to make strong conclusions from the data. One of the ways to conclude the strength of the ϕ meson mass shift in nuclei will be by trying to produce only slowly moving ϕ mesons where the maximum nuclear matter effect can be probed. The observed mass reduction of the ϕ meson in the nucleus can be translated as the existence of an attractive force between ϕ meson and nucleus. Thus, one of the extreme conditions that can be achieved in the laboratory is indeed the formation of a ϕ-nucleus bound state, where the ϕ meson is "trapped" in the nucleus. The purpose of the experiment is to search for a ϕ-nucleus bound state and measure the binding energy of the system. We will demonstrate that a completely background-free missing-mass spectrum can be obtained efficiently by (bar{p}, φ) spectroscopy together with K + Λ tagging, using the primary reaction channel bar{p} p rightarrow φ φ. This paper gives an overview of the physics motivation and the detector concept, and explains the direction of the initial research and development effort.

  8. Dynamical description of the moments of the energy distribution of fission fragments and scission of a fissile nucleus

    SciTech Connect

    Borunov, M. V. Nadtochy, P. N.; Adeev, G. D.

    2007-11-15

    A multidimensional stochastic approach to fission dynamics on the basis of three-dimensional Langevin equations is applied systematically to calculating the first four moments of the energy distribution of fission fragments over a broad range of Coulomb parameter values (700 < Z{sup 2}/A{sup 1/3} < 1700). For the scission of a fissile nucleus into fragments, use was made of various criteria traditional in modern fission theory: the vanishing of the neck radius at the scission instant and the equality of the neck radius to about 0.3R{sub 0} at this instant. In calculating the energy distribution, both of the criteria used lead to a fairly good description of experimental data on the first two moments and to a satisfactory description of data on the third and fourth moments of the distribution. However, the quality of the description of available experimental data is insufficiently good for giving preference to any of these criteria. Within three-dimensional Langevin dynamics, it is shown that the vanishing-radius criterion leads to unexpectably good agreement with experimental data on the first four moments of the energy distribution. A modified version of one-body dissipation where the coefficient that takes into account the reduction of the wall-formula contribution was set to k{sub s} = 0.25 was used in the calculations.

  9. Dynamic risk control by human nucleus accumbens.

    PubMed

    Nachev, Parashkev; Lopez-Sosa, Fernando; Gonzalez-Rosa, Javier Jesus; Galarza, Ana; Avecillas, Josue; Pineda-Pardo, Jose Angel; Lopez-Ibor, Juan José; Reneses, Blanca; Barcia, Juan Antonio; Strange, Bryan

    2015-12-01

    Real-world decisions about reward often involve a complex counterbalance of risk and value. Although the nucleus accumbens has been implicated in the underlying neural substrate, its criticality to human behaviour remains an open question, best addressed with interventional methodology that probes the behavioural consequences of focal neural modulation. Combining a psychometric index of risky decision-making with transient electrical modulation of the nucleus accumbens, here we reveal profound, highly dynamic alteration of the relation between probability of reward and choice during therapeutic deep brain stimulation in four patients with treatment-resistant psychiatric disease. Short-lived phasic electrical stimulation of the region of the nucleus accumbens dynamically altered risk behaviour, transiently shifting the psychometric function towards more risky decisions only for the duration of stimulation. A critical, on-line role of human nucleus accumbens in dynamic risk control is thereby established.

  10. Microtubules move the nucleus to quiescence.

    PubMed

    Laporte, Damien; Sagot, Isabelle

    2014-01-01

    The nucleus is a cellular compartment that hosts several macro-molecular machines displaying a highly complex spatial organization. This tight architectural orchestration determines not only DNA replication and repair but also regulates gene expression. In budding yeast microtubules play a key role in structuring the nucleus since they condition the Rabl arrangement in G1 and chromosome partitioning during mitosis through their attachment to centromeres via the kinetochore proteins. Recently, we have shown that upon quiescence entry, intranuclear microtubules emanating from the spindle pole body elongate to form a highly stable bundle that spans the entire nucleus. Here, we examine some molecular mechanisms that may underlie the formation of this structure. As the intranuclear microtubule bundle causes a profound re-organization of the yeast nucleus and is required for cell survival during quiescence, we discuss the possibility that the assembly of such a structure participates in quiescence establishment.

  11. Dynamic risk control by human nucleus accumbens

    PubMed Central

    Lopez-Sosa, Fernando; Gonzalez-Rosa, Javier Jesus; Galarza, Ana; Avecillas, Josue; Pineda-Pardo, Jose Angel; Lopez-Ibor, Juan José; Reneses, Blanca; Barcia, Juan Antonio

    2015-01-01

    Real-world decisions about reward often involve a complex counterbalance of risk and value. Although the nucleus accumbens has been implicated in the underlying neural substrate, its criticality to human behaviour remains an open question, best addressed with interventional methodology that probes the behavioural consequences of focal neural modulation. Combining a psychometric index of risky decision-making with transient electrical modulation of the nucleus accumbens, here we reveal profound, highly dynamic alteration of the relation between probability of reward and choice during therapeutic deep brain stimulation in four patients with treatment-resistant psychiatric disease. Short-lived phasic electrical stimulation of the region of the nucleus accumbens dynamically altered risk behaviour, transiently shifting the psychometric function towards more risky decisions only for the duration of stimulation. A critical, on-line role of human nucleus accumbens in dynamic risk control is thereby established. PMID:26428667

  12. The Checkerboard Model of the Nucleus

    NASA Astrophysics Data System (ADS)

    Lach, Theodore

    2014-03-01

    The Lach Checker Board Model (CBM) of the nucleus and the associated ESM predicts that nature has 5 generations of quarks not 3. The heaviest generation in the Extended Standard Model (ESM) has a t' quark of mass 65 GeV and a b' quark of 42.4 GeV. The lepton in this generation has a mass of 27 GeV. Part of this theory evolved because it appears that the quarks and lepton of each generation have masses related by the geometric mean. The Geometric mean of 65 and 27 is 42. Charge is conserved (+2/3 and -1 is -1/3). Details of how this theory evolved is found on my web site (http://checkerboard.dnsalias.net) or in the following references [T.M. Lach, Checkerboard Structure of the Nucleus, Infinite Energy, Vol. 5, issue 30, (2000); T.M. Lach, Masses of the Sub-Nuclear Particles, nucl-th/0008026, @http://xxx.lanl.gov/] One independent check of this CB model is that the wavelength of the ``up'' quark orbiting inside the proton at 84.8123% the speed of light around the ``dn'' quark in the center turns out to be exactly one DeBroglie wavelength. This explains the mass of the proton and neutron and their magnetic moments. This along with the beautiful symmetric 2D structure of the He nucleus led to the evolution of this theory. One would expect a t'-anti t' meson of mass of about 130 GeV.

  13. Improved Cloud Condensation Nucleus Spectrometer

    NASA Technical Reports Server (NTRS)

    Leu, Ming-Taun

    2010-01-01

    An improved thermal-gradient cloud condensation nucleus spectrometer (CCNS) has been designed to provide several enhancements over prior thermal- gradient counters, including fast response and high-sensitivity detection covering a wide range of supersaturations. CCNSs are used in laboratory research on the relationships among aerosols, supersaturation of air, and the formation of clouds. The operational characteristics of prior counters are such that it takes long times to determine aerosol critical supersaturations. Hence, there is a need for a CCNS capable of rapid scanning through a wide range of supersaturations. The present improved CCNS satisfies this need. The improved thermal-gradient CCNS (see Figure 1) incorporates the following notable features: a) The main chamber is bounded on the top and bottom by parallel thick copper plates, which are joined by a thermally conductive vertical wall on one side and a thermally nonconductive wall on the opposite side. b) To establish a temperature gradient needed to establish a supersaturation gradient, water at two different regulated temperatures is pumped through tubes along the edges of the copper plates at the thermally-nonconductive-wall side. Figure 2 presents an example of temperature and supersaturation gradients for one combination of regulated temperatures at the thermally-nonconductive-wall edges of the copper plates. c) To enable measurement of the temperature gradient, ten thermocouples are cemented to the external surfaces of the copper plates (five on the top plate and five on the bottom plate), spaced at equal intervals along the width axis of the main chamber near the outlet end. d) Pieces of filter paper or cotton felt are cemented onto the interior surfaces of the copper plates and, prior to each experimental run, are saturated with water to establish a supersaturation field inside the main chamber. e) A flow of monodisperse aerosol and a dilution flow of humid air are introduced into the main

  14. Delta-nucleus dynamics: proceedings of symposium

    SciTech Connect

    Lee, T.S.H.; Geesaman, D.F.; Schiffer, J.P.

    1983-10-01

    The appreciation of the role in nuclear physics of the first excited state of the nucleon, the delta ..delta..(1232), has grown rapidly in the past decade. The delta resonance dominates nuclear reactions induced by intermediate energy pions, nucleons, and electromagnetic probes. It is also the most important non-nucleonic degree of freedom needed to resolve many fundamental problems encountered in the study of low-energy nuclear phenomena. Clearly, a new phase of nuclear physics has emerged and conventional thinking must be extended to account for this new dimension of nuclear dynamics. The most challenging problem we are facing is how a unified theory can be developed to describe ..delta..-nucleus dynamics at all energies. In exploring this new direction, it is important to have direct discussions among researchers with different viewpoints. Separate entries were prepared for the 49 papers presented. (WHK)

  15. Stopping powers and cross sections due to two-photon processes in relativistic nucleus-nucleus collisions

    NASA Technical Reports Server (NTRS)

    Cheung, Wang K.; Norbury, John W.

    1994-01-01

    The effects of electromagnetic-production processes due to two-photon exchange in nucleus-nucleus collisions are discussed. Feynman diagrams for two-photon exchange are evaluated using quantum electrodynamics. The total cross section and stopping power for projectile and target nuclei of identical charge are found to be significant for heavy nuclei above a few GeV per nucleon-incident energy.

  16. Experimental evidence and the Landau-Zener promotion in nucleus-nucleus collisions

    SciTech Connect

    Cindro, N.; Freeman, R.M.; Haas, F.

    1986-04-01

    Recent data from C+O collisions are analyzed in terms of the Landau-Zener promotion in nuclei. Evidence for the presence of this mechanism in nuclear collisions is of considerable interest, since it provides a signature of single-particle orbitals in molecular-type potentials and, at the same time, paves the way to a microscopic understanding of the collision dynamics, in particular of the energy dissipation rate. The analyzed data are of two types: integrated cross sections and angular distributions of inelastically scattered particles. The first set of data shows structure qualitatively consistent with recent calculations of the Landau-Zener effect; for this set of data no other reasonable explanation is presently available. The second set of data, while consistent with the presence of the Landau-Zener promotion, is examined in terms of other possible explanations too. The combined data show evidence favoring the presence of the Landau-Zener promotion in nucleus-nucleus collisions.

  17. Experimental studies of pion-nucleus interactions at intermediate energies. [New Mexico State Univ. , Las Cruces, New Mexico

    SciTech Connect

    Not Available

    1992-12-31

    This report summarizes investigations of various pion-nucleus interactions and nucleon-nucleus charge-exchange reactions. The work was carried out with the LAMPF accelerator at the Los Alamos National Laboratory and the cyclotrons at the Paul Scherrer Institute (PSI) near Zurich, Switzerland, and at Indiana University (IUCF), as a collaborative effort among several laboratories and universities. The experimental activity at LAMPF involved measurements of new data on pion double-charge-exchange scattering, some initial work on a new Neutral Meson Spectrometer system, a search for deeply-bound pionic atoms, measurements of elastic scattering, and studies of the (n,p) reaction on various nuclei. At PSI measurements of pion quasielastic scattering were carried out, with detection of the recoil proton. Work on the analysis of data from a previous experiment at PSI on pion absorption in nuclei was continued. This experiment involved using a detector system that covered nearly the full solid angle.

  18. Melanocortin 4 receptor ligands modulate energy homeostasis through urocortin 1 neurons of the centrally projecting Edinger-Westphal nucleus.

    PubMed

    Füredi, Nóra; Nagy, Ákos; Mikó, Alexandra; Berta, Gergely; Kozicz, Tamás; Pétervári, Erika; Balaskó, Márta; Gaszner, Balázs

    2017-03-03

    The role of the urocortin 1 (Ucn1) expressing centrally projecting Edinger-Westphal (EWcp) nucleus in energy homeostasis and stress adaptation response has previously been investigated. Morphological and functional studies have proven that orexigenic and anorexigenic peptidergic afferents and receptors for endocrine messengers involved in the energy homeostasis are found in the EWcp. The central role of the hypothalamic melanocortin system in energy homeostasis is well known, however, no data have been published so far on possible crosstalk between melanocortins and EWcp-Ucn1. First, we hypothesized that members of the melanocortin system [i.e. alpha-melanocyte stimulating hormone (alpha-MSH), agouti-related peptide (AgRP), melanocortin 4 receptor (MC4R)] would be expressed in the EWcp. Second, we put forward, that alpha-MSH and AgRP contents as well as neuronal activity and Ucn1 peptide content of the EWcp would be affected by fasting. Third, we assumed that the intra-EWcp injections of exogenous MC4R agonists and antagonist would cause food intake-related and metabolic changes. Ucn1 neurons were found to carry MC4Rs, and they were contacted both by alpha-MSH and AgRP immunoreactive nerve fibers in the rat. The alpha-MSH immunosignal was reduced, while that of AgRP was increased upon starvation. These were associated with the elevation of FosB and Ucn1 expression. The intra-EWcp administration of MC4R blocker (i.e. HS024) had a similar, but enhanced effect on FosB and Ucn1. Furthermore, alpha-MSH injected into the EWcp had anorexigenic effect, increased oxygen consumption and caused peripheral vasodilation. We conclude that the melanocortin system influences the EWcp that contributes to energy-homeostasis.

  19. Direct photon production and jet energy-loss in small systems. The XXVth International Conference on Ultrarelativistic Nucleus-Nucleus Collisions

    NASA Astrophysics Data System (ADS)

    Shen, Chun; Park, Chanwook; Paquet, Jean-François; Denicol, Gabriel S.; Jeon, Sangyong; Gale, Charles

    2016-12-01

    Two types of penetrating probes, direct photon and QCD jets, are investigated in the background of a small and rapidly expanding droplet of quark-gluon plasma. The additional thermal electromagnetic radiation results in a ∼50% enhancement of the direct photons. In high multiplicity p+Pb collisions, jets can lose a sizeable fraction of their initial energy, leading to a charged hadron RpA of ∼0.8 at a transverse momentum around 10GeV. Those two proposed measurements can help understand the apparent collective behaviour observed in small collision systems.

  20. Dynamical evolution of comet nucleus rotation

    NASA Astrophysics Data System (ADS)

    Scheeres, D. J.; Sidorenko, V. V.; Neishtadt, A. I.; Vasiliev, A. A.

    2001-11-01

    The rotational dynamics of outgassing cometary nuclei are investigated analytically using dynamical systems theory. We develop a general theory for the averaged evolution of a comet nucleus rotation state assuming that the nucleus is a spheroid (either prolate or oblate) and that the outgassing torques are a function of solar insolation and heliocentric distance. The resulting solutions are a function of the comet outgassing properties, its heliocentric orbit, and the assumed distribution of active regions on its surface. We find that the long-term evolution of the comet nucleus rotation is a strong function of the distribution of active regions over its surface. Specifically, we find that a comet nucleus with a uniformly active surface will tend towards a rotation state with a nutation angle of ~ 55 degrees and an angular momentum perpendicular to the sun-perihelion direction. Conversely, a comet nucleus with an isolated active region will tend towards a zero nutation angle with its symmetry axis and angular momentum aligned parallel to the sun-perihelion direction. For active surface regions between these extremes we find 4 qualitatively different dynamical outcomes. In all cases, the theory predicts that the comet nucleus angular momentum will have a secular increase, a phenomenon that could contribute to nucleus splitting of active comets. These results can be used to discriminate between competing theories of comet outgassing based on a nucelus' rotation state. They also allow for a range of plausible a priori constraints to be placed on a comet's rotation state to aid in the interpretation of its outgassing structure. This work was supported by the NASA JURRISS program under Grant NAG5-8715. AIN, AAV and VVS acknowledge support from Russian Foundation for Basic research via Grants 00-01-00538 and 00-01-0174 respectively. DJS acknowledges support from the PG&G program via Grant NAG5-9017.

  1. High energy (gamma)-ray emission from the starburst nucleus of NGC 253

    SciTech Connect

    Domingo-Santamaria, E; Torres, D F

    2005-06-15

    The high density medium that characterizes the central regions of starburst galaxies and its power to accelerate particles up to relativistic energies make these objects good candidates as {gamma}-rays sources. In this paper, a self-consistent model of the multifrequency emission of the starburst galaxy NGC 253, from radio to gamma-rays, is presented. The model is in agreement with all current measurements and provides predictions for the high energy behavior of the NGC 253 central region. Prospects for observations with the HESS array and GLAST satellite are especially discussed.

  2. Recent developments in neutrino-nucleus interactions in 1 GeV energy region

    SciTech Connect

    Sobczyk, Jan T.

    2015-07-15

    Neutrino interactions in 1 GeV energy region are discussed. A role of nucleon-nucleon correlations in understanding recent quasi-elastic cross section measurements on nuclear target is explained. An importance of a correct treatment of two-body current contribution to the neutrino inclusive cross section is addressed.

  3. Nonexistence of the Oppenheimer-Phillips process in low-energy deuteron-nucleus collisions

    SciTech Connect

    Bencze, G.; Chandler, C.

    1996-02-01

    It is shown that the electric polarizability of the deuteron produces negligible effect on the cross section of deuteron induced rearrangement reactions even at extremely low energies. This assessment is based on simple analytical formulas, derived on the basis of {ital N}-particle scattering theory by means of the general two-potential formalism, including Coulomb and exchange effects. It is shown on the basis of general physical arguments that the polarizability effects at very low energies are entirely contained in a multiplicative enhancement factor that differs from 1 by at most a few percent. As a result enhancement of ({ital d},{ital p}) relative to ({ital d},{ital n}) reactions is not possible by the Oppenheimer-Phillips mechanism.

  4. Nonexistence of the Oppenheimer-Phillips process in low-energy deuteron-nucleus collisions

    NASA Astrophysics Data System (ADS)

    Bencze, Gy.; Chandler, Colston

    1996-02-01

    It is shown that the electric polarizability of the deuteron produces negligible effect on the cross section of deuteron induced rearrangement reactions even at extremely low energies. This assessment is based on simple analytical formulas, derived on the basis of N-particle scattering theory by means of the general two-potential formalism, including Coulomb and exchange effects. It is shown on the basis of general physical arguments that the polarizability effects at very low energies are entirely contained in a multiplicative enhancement factor that differs from 1 by at most a few percent. As a result enhancement of (d,p) relative to (d,n) reactions is not possible by the Oppenheimer-Phillips mechanism.

  5. NAD+ metabolism and the control of energy homeostasis - a balancing act between mitochondria and the nucleus

    PubMed Central

    Cantó, Carles; Menzies, Keir; Auwerx, Johan

    2015-01-01

    NAD+ has emerged as a vital cofactor that can rewire metabolism, activate sirtuins and maintain mitochondrial fitness through mechanisms such as the mitochondrial unfolded protein response. This improved understanding of NAD+ metabolism revived interest in NAD+ boosting strategies to manage a wide spectrum of diseases, ranging from diabetes to cancer. In this review, we summarize how NAD+ metabolism links energy status with adaptive cellular and organismal responses and how this knowledge can be therapeutically exploited. PMID:26118927

  6. NAD(+) Metabolism and the Control of Energy Homeostasis: A Balancing Act between Mitochondria and the Nucleus.

    PubMed

    Cantó, Carles; Menzies, Keir J; Auwerx, Johan

    2015-07-07

    NAD(+) has emerged as a vital cofactor that can rewire metabolism, activate sirtuins, and maintain mitochondrial fitness through mechanisms such as the mitochondrial unfolded protein response. This improved understanding of NAD(+) metabolism revived interest in NAD(+)-boosting strategies to manage a wide spectrum of diseases, ranging from diabetes to cancer. In this review, we summarize how NAD(+) metabolism links energy status with adaptive cellular and organismal responses and how this knowledge can be therapeutically exploited.

  7. Cell survival fraction estimation based on the probability densities of domain and cell nucleus specific energies using improved microdosimetric kinetic models.

    PubMed

    Sato, Tatsuhiko; Furusawa, Yoshiya

    2012-10-01

    Estimation of the survival fractions of cells irradiated with various particles over a wide linear energy transfer (LET) range is of great importance in the treatment planning of charged-particle therapy. Two computational models were developed for estimating survival fractions based on the concept of the microdosimetric kinetic model. They were designated as the double-stochastic microdosimetric kinetic and stochastic microdosimetric kinetic models. The former model takes into account the stochastic natures of both domain and cell nucleus specific energies, whereas the latter model represents the stochastic nature of domain specific energy by its approximated mean value and variance to reduce the computational time. The probability densities of the domain and cell nucleus specific energies are the fundamental quantities for expressing survival fractions in these models. These densities are calculated using the microdosimetric and LET-estimator functions implemented in the Particle and Heavy Ion Transport code System (PHITS) in combination with the convolution or database method. Both the double-stochastic microdosimetric kinetic and stochastic microdosimetric kinetic models can reproduce the measured survival fractions for high-LET and high-dose irradiations, whereas a previously proposed microdosimetric kinetic model predicts lower values for these fractions, mainly due to intrinsic ignorance of the stochastic nature of cell nucleus specific energies in the calculation. The models we developed should contribute to a better understanding of the mechanism of cell inactivation, as well as improve the accuracy of treatment planning of charged-particle therapy.

  8. Effects of subthalamic nucleus deep brain stimulation and levodopa on energy production rate and substrate oxidation in Parkinson's disease.

    PubMed

    Perlemoine, Caroline; Macia, Frédéric; Tison, François; Coman, Isabelle; Guehl, Dominique; Burbaud, Pierre; Cuny, Emmanuel; Baillet, Laurence; Gin, Henri; Rigalleau, Vincent

    2005-02-01

    Patients with Parkinson's disease (PD) often lose weight, but after subthalamic nucleus deep brain stimulation (STN-DBS), they gain weight. We compared daily energy intake (DEI), resting energy expenditure (REE) and substrate oxidation rates (measured by indirect calorimetry) in nineteen STN-DBS-treated patients (Group S), thirteen others on pharmacologic treatment by levodopa (Group L) and eight control subjects. We also determined the acute effects of STN-DBS and levodopa on REE and substrate oxidation rates. STN-DBS treated patients gained 9.7 (SEM 7.1) kg after surgery, whereas patients on pharmacologic treatment lost 3.8 (SEM 10.0) kg since diagnosis. In STN-DBS-treated patients, REE (-16.5 %; P<0.001), lipid oxidation (-27 %; P<0.05) and protein oxidation (-46 %; P<0.05) were decreased, whereas glucose oxidation was elevated (+81 %; P<0.05) as compared to patients on pharmacologic treatment. Levodopa acutely reduced REE (-8.3 %; P<0.05) and glucose oxidation (-37 %; P<0.01) with a slight hyperglycaemic effect (after levodopa challenge: 5.6 (SEM 0.8) v. before levodopa challenge: 5.3 (SEM 0.6) mmol/l; P<0.01). Switching 'on' STN-DBS acutely reduced REE (-17.5 %; P<0.01) and lipid oxidation (-24 %; P<0.001) 30 min after starting stimulation. Fasting glycaemia was slightly but significantly reduced (5.4 (SEM 1.4) v. 5.5 (SEM 1.3) mmol/l; P<0.01). After STN-DBS, the normalization of REE and the reduction in lipid and protein oxidation contribute to the restoration of weight. As levodopa decreases glucose oxidation, the reduction in daily dose of levodopa in STN-DBS-treated patients helps prevent the effect of weight gain on glycaemia.

  9. The dynamic landscape of the cell nucleus.

    PubMed

    Austin, Christopher M; Bellini, Michel

    2010-01-01

    While the cell nucleus was described for the first time almost two centuries ago, our modern view of the nuclear architecture is primarily based on studies from the last two decades. This surprising late start coincides with the development of new, powerful strategies to probe for the spatial organization of nuclear activities in both fixed and live cells. As a result, three major principles have emerged: first, the nucleus is not just a bag filled with nucleic acids and proteins. Rather, many distinct functional domains, including the chromosomes, resides within the confines of the nuclear envelope. Second, all these nuclear domains are highly dynamic, with molecules exchanging rapidly between them and the surrounding nucleoplasm. Finally, the motion of molecules within the nucleoplasm appears to be mostly driven by random diffusion. Here, the emerging roles of several subnuclear domains are discussed in the context of the dynamic functions of the cell nucleus.

  10. Organisation of the human dorsomedial hypothalamic nucleus.

    PubMed

    Koutcherov, Yuri; Mai, Juergen K; Ashwell, Ken W; Paxinos, George

    2004-01-19

    This study used acetylcholinesterase (AChE) histochemistry to reveal the organization of the dorsomedial hypothalamic nucleus (DM) in the human. Topographically, the human DM is similar to DM in the monkey and rat. It is wedged between the paraventricular nucleus, dorsally, and the ventromedial nucleus, ventrally. Laterally, DM borders the lateral hypothalamic area while medially it approaches the 3rd ventricle. The AChE staining distinguished two subcompartments of the human DM: the larger diffuse and the smaller compact DM. The subcompartmental organization of the human DM appears homologous to that found in the monkey and less complex than that reported in rats. Understanding of the organization of DM creates meaningful anatomical reference for physiological and pharmacological studies in the human hypothalamus.

  11. Nucleus model for periodic Comet Tempel 2

    NASA Technical Reports Server (NTRS)

    Sekanina, Zdenek

    1991-01-01

    Observational data obtained primarily during 1988 are analyzed and synthesized to develop a comprehensive physical model for the nucleus of Periodic Comet Tempel 2, one of the best studied members of Jupiter's family of short-period comets. It is confirmed that a previous investigation provided reliable information on the comet's spin-axis orientation, which implies and obliquity of 54 degrees of the orbit plane to the equatorial plane and which appears to have varied little - if at all - with time. This conclusion is critical for fitting a triaxial ellipsoid to approximate the figure of the nucleus.

  12. UNCOVERING THE NUCLEUS CANDIDATE FOR NGC 253

    SciTech Connect

    Günthardt, G. I.; Camperi, J. A.; Agüero, M. P.; Díaz, R. J.; Gomez, P. L.; Schirmer, M.; Bosch, G. E-mail: camperi@oac.uncor.edu E-mail: rdiaz@gemini.edu E-mail: mschirmer@gemini.edu

    2015-11-15

    NGC 253 is the nearest spiral galaxy with a nuclear starburst that becomes the best candidate for studying the relationship between starburst and active galactic nucleus activity. However, this central region is veiled by large amounts of dust, and it has been so far unclear which is the true dynamical nucleus to the point that there is no strong evidence that the galaxy harbors a supermassive black hole co-evolving with the starburst as was supposed earlier. Near-infrared (NIR) spectroscopy, especially NIR emission line analysis, could be advantageous in shedding light on the true nucleus identity. Using Flamingos-2 at Gemini South we have taken deep K-band spectra along the major axis of the central structure and through the brightest infrared source. In this work, we present evidence showing that the brightest NIR and mid-infrared source in the central region, already known as radio source TH7 and so far considered just a large stellar supercluster, in fact presents various symptoms of a genuine galactic nucleus. Therefore, it should be considered a valid nucleus candidate. Mentioning some distinctive aspects, it is the most massive compact infrared object in the central region, located at 2.″0 of the symmetry center of the galactic bar, as measured in the K-band emission. Moreover, our data indicate that this object is surrounded by a large circumnuclear stellar disk and it is also located at the rotation center of the large molecular gas disk of NGC 253. Furthermore, a kinematic residual appears in the H{sub 2} rotation curve with a sinusoidal shape consistent with an outflow centered in the candidate nucleus position. The maximum outflow velocity is located about 14 pc from TH7, which is consistent with the radius of a shell detected around the nucleus candidate, observed at 18.3 μm (Qa) and 12.8 μm ([Ne ii]) with T-ReCS. Also, the Brγ emission line profile shows a pronounced blueshift and this emission line also has the highest equivalent width at this

  13. Uncovering the Nucleus Candidate for NGC 253

    NASA Astrophysics Data System (ADS)

    Günthardt, G. I.; Agüero, M. P.; Camperi, J. A.; Díaz, R. J.; Gomez, P. L.; Bosch, G.; Schirmer, M.

    2015-11-01

    NGC 253 is the nearest spiral galaxy with a nuclear starburst that becomes the best candidate for studying the relationship between starburst and active galactic nucleus activity. However, this central region is veiled by large amounts of dust, and it has been so far unclear which is the true dynamical nucleus to the point that there is no strong evidence that the galaxy harbors a supermassive black hole co-evolving with the starburst as was supposed earlier. Near-infrared (NIR) spectroscopy, especially NIR emission line analysis, could be advantageous in shedding light on the true nucleus identity. Using Flamingos-2 at Gemini South we have taken deep K-band spectra along the major axis of the central structure and through the brightest infrared source. In this work, we present evidence showing that the brightest NIR and mid-infrared source in the central region, already known as radio source TH7 and so far considered just a large stellar supercluster, in fact presents various symptoms of a genuine galactic nucleus. Therefore, it should be considered a valid nucleus candidate. Mentioning some distinctive aspects, it is the most massive compact infrared object in the central region, located at 2.″0 of the symmetry center of the galactic bar, as measured in the K-band emission. Moreover, our data indicate that this object is surrounded by a large circumnuclear stellar disk and it is also located at the rotation center of the large molecular gas disk of NGC 253. Furthermore, a kinematic residual appears in the H2 rotation curve with a sinusoidal shape consistent with an outflow centered in the candidate nucleus position. The maximum outflow velocity is located about 14 pc from TH7, which is consistent with the radius of a shell detected around the nucleus candidate, observed at 18.3 μm (Qa) and 12.8 μm ([Ne ii]) with T-ReCS. Also, the Brγ emission line profile shows a pronounced blueshift and this emission line also has the highest equivalent width at this

  14. Calculated dynamical evolution of the nucleus of comet Hartley 2

    NASA Astrophysics Data System (ADS)

    Ksanfomality, Leonid

    2013-04-01

    The nucleus of comet Hartley 2 has a relatively regular dumbbell shape with unequal heads. The narrow part of elongated shape contains a relatively smooth region whose covering material is highly different in its shallow structure compared to other parts of this celestial body. The surface of crudely spherical parts of the nucleus is different from the surface of the "neck", which implies a hypothesis that the shape of the nucleus of Hartley 2 is indicative of destruction of this celestial body occurring in our days. The nucleus rotates around its axis passing through the center of mass, and centrifugal forces arise. This process is hindered by gravitation between parts of the nucleus and gradual slowing of rotation due to body lengthening because of the increase in the moment of inertia (proportional to R2) and due to friction losses in the neck material. We posed the task to determine centrifugal and gravitational forces in the neck (and, respectively, the strains of stretching and compression), the moment of inertia of the body and supply of its rotational energy E, the volume of the nucleus and its average density, and the position of the barycenter and center of rotation. It can be assumed that these forces cause slow but progressive lengthening of the neck which should eventually result in fragmentation of the nucleus. Centrifugal forces can be found as a result of summation of forces produced by parts of the body. According to the calculation model, the total stretching forces in the section passing through the narrowest cut of the neck are 1.21E6 N. The corresponding compression forces in the section passing through the narrow section are 1.04E6 N. The comparison of these values indicates a paradoxical result: stretching strains dominate in the neck, while compressions are dominant in the section passing through the common center of mass. The excess of stretching strains in the neck is 11%. The inference is as follows: the right part of the neck and the

  15. Mass dependence of critical behavior in nucleus-nucleus collisions

    SciTech Connect

    Li, T.; Bauer, W.; Craig, D.; Gualtieri, E.; Hannuschke, S.; Pak, R.; Vander Molen, A.M.; Westfall, G.D.; Winfield, J.S.; Yee, J.; Yennello, S.J.; Lacey, R.; Nadasen, A.; Tickle, R.S.; Norbeck, E.

    1994-03-01

    The {ital Z} distributions of fragments emitted from central collisions of {sup 40}Ar+{sup 45}Sc at beam energies from 15 to 115 MeV/nucleon have been fitted to power laws {sigma}({ital Z}){proportional_to}{ital Z}{sup {minus}{lambda}}. The {lambda} parameter reaches a minimum at a beam energy of 23.9{plus_minus}0.7 MeV/nucleon. A percolation model calculation reproduces the observed {ital Z} distributions for all beam energies, using the mean excitation energy as extracted from proton kinetic energy spectra. We extract the critical value of the deposited excitation energy for our system and make predictions for the dependence of this quantity on the size of the fragmenting system.

  16. Gamma-ray spectroscopy of the nucleus 139Ce

    NASA Astrophysics Data System (ADS)

    Bucurescu, D.; Căta-Danil, G.; Căta-Danil, I.; Ivaşcu, M.; Mărginean, N.; Mărginean, R.; Mihăilescu, L. C.; Rusu, C.; Suliman, G.

    2006-03-01

    Gamma-ray coincidence techniques are used to determine new level structures in the N = 81 nucleus 139Ce, at low spins and excitation energies with the 139La(p, nγ) reaction at 5.0 and 6.0MeV incident energy, and at high spins with the 130Te(12C, 3nγ) reaction at 50.5MeV, respectively. Lifetime determinations are also made in the (p, nγ) reaction with the centroid DSA method. The observed level structures are discussed by comparison with existing calculations and with those in the neighbouring nucleus 140Ce.

  17. Exclusive experiment on nuclei with backward emitted particles by electron-nucleus collision in {approximately} 10 GeV energy range

    SciTech Connect

    Saito, T.; Takagi, F.

    1994-04-01

    Since the evidence of strong cross section in proton-nucleus backward scattering was presented in the early of 1970 years, this phenomena have been interested from the point of view to be related to information on the short range correlation between nucleons or on high momentum components of the wave function of the nucleus. In the analysis of the first experiment on protons from the carbon target under bombardment by 1.5-5.7 GeV protons, indications are found of an effect analogous to scaling in high-energy interactions of elementary particles with protons. Moreover it is found that the function f(p{sup 2})/{sigma}{sub tot}, which describes the spectra of the protons and deuterons emitted backward from nuclei in the laboratory system, does not depend on the energy and the type of the incident particle or on the atomic number of the target nucleus. In the following experiments the spectra of the protons emitted from the nuclei C, Al, Ti, Cu, Cd and Pb were measured in the inclusive reactions with incident particles of negative pions (1.55-6.2 GeV/c) and protons (6.2-9.0 GeV/C). The cross section f is described by f = E/p{sup 2} d{sup 2}{sigma}/dpd{Omega} = C exp ({minus}Bp{sup 2}), where p is the momentum of hadron. The function f depends linearly on the atomic weight A of the target nuclei. The slope parameter B is independent of the target nucleus and of the sort and energy of the bombarding particles. The invariant cross section {rho} = f/{sigma}{sub tot} is also described by exponential A{sub 0} exp ({minus}A{sub 1p}{sup 2}), where p becomes independent of energy at initial particle energies {ge} 1.5 GeV for C nucleus and {ge} 5 GeV for the heaviest of the investigated Pb nuclei.

  18. The Checkerboard Model of the Nucleus

    NASA Astrophysics Data System (ADS)

    Lach, Theodore

    2015-04-01

    The Checker Board Model (CBM) of the nucleus and the associated extended standard model predicts that nature has 5 generations of quarks not 3 and that Nucleus is 2 dimensional. The CBM theory began with an insight into the structure of the He nucleus around the year 1989. Details of how this theory evolved which took many years, and is found on my web site (http://checkerboard.dnsalias.net) or in the following references One independent check of this model is that the wavelength of the ``up'' quark orbiting inside the proton at 84.8123% the speed of light (around the ``dn'' quark in the center of the proton) turns out to be exactly one de Broglie wavelength something determined after the mass and speed of the up quark were determined by other means. This theory explains the mass of the proton and neutron and their magnetic moments and this along with the beautiful symmetric 2D structure of the He nucleus led to the evolution of this theory. When this theory was first presented at Argonne in 1996, it was the first time that anyone had predicted the quarks orbited inside the proton at relativistic speeds and it was met with skepticism.

  19. New developments in nucleus pulposus replacement technology.

    PubMed

    Carl, Allen; Ledet, Eric; Yuan, Hansen; Sharan, Alok

    2004-01-01

    Attempts to alleviate the pain attributed to degeneration of the nucleus pulposus using replacement or reinforcement techniques dating back to the 1950s are reviewed. The various materials and their insertion techniques are discussed as are results available from early clinical experiences. These techniques are in evolution and clinical outcomes will be necessary to establish the efficacy of these approaches.

  20. Nucleus-associated actin in Amoeba proteus.

    PubMed

    Berdieva, Mariia; Bogolyubov, Dmitry; Podlipaeva, Yuliya; Goodkov, Andrew

    2016-10-01

    The presence, spatial distribution and forms of intranuclear and nucleus-associated cytoplasmic actin were studied in Amoeba proteus with immunocytochemical approaches. Labeling with different anti-actin antibodies and staining with TRITC-phalloidin and fluorescent deoxyribonuclease I were used. We showed that actin is abundant within the nucleus as well as in the cytoplasm of A. proteus cells. According to DNase I experiments, the predominant form of intranuclear actin is G-actin which is associated with chromatin strands. Besides, unpolymerized actin was shown to participate in organization of a prominent actin layer adjacent to the outer surface of nuclear envelope. No significant amount of F-actin was found in the nucleus. At the same time, the amoeba nucleus is enclosed in a basket-like structure formed by circumnuclear actin filaments and bundles connected with global cytoplasmic actin cytoskeleton. A supposed architectural function of actin filaments was studied by treatment with actin-depolymerizing agent latrunculin A. It disassembled the circumnuclear actin system, but did not affect the intranuclear chromatin structure. The results obtained for amoeba cells support the modern concept that actin is involved in fundamental nuclear processes that have evolved in the cells of multicellular organisms.

  1. Phase Evolution and Nucleus Growth Observation of Solid-State BaTiO3 Powder Prepared by High-Energy Bead Milling for Raw Material Mixing

    NASA Astrophysics Data System (ADS)

    Lee, Ting-Tai; Huang, Chi-Yuen; Chang, Che-Yuan; Lin, Shih-Pin; Su, Che-Yi; Lee, Chun-Te; Fujimoto, Masayuki

    2011-09-01

    The solid-state synthesis, phase evolution, and nucleus growth of the barium titanate (BaTiO3, BT) powder were investigated in this study. Rapid nucleus growth and precursor phase formation of BT were observed at a relatively low temperature of 600 °C by mixing BaCO3 (2 m2/g) and TiO2 (7 m2/g) with a high-energy bead mill. The decomposition of BaCO3 and the formation of the Ba2TiO4 phase were identified by transmission electron microscopy (TEM). On the basis of this observation, the weight loss observed at 600 °C in the derivative thermogravimetry (DTG) curve could also be explained. Furthermore, with increasing calcination temperature, single cubic BT with less than 80 nm fine nuclei/crystallites was observed at 900 °C, and tetragonal BT (c/a > 1.008) with an average particle size of 0.4 µm was obtained at 1000 °C. With regard to the dielectric properties of sintered ceramics, the relative permittivity (ɛr) increased with calcination temperature, and the Curie point also shifted to a progressively higher temperature. However, BT nucleus samples (with low calcination temperatures of 800 and 900 °C) could not satisfy the X7R requirement (Electric Industries Association Standard, the tolerance of capacitance from -55 to +125 °C is ±15%) until calcination temperature increased to 1000 °C.

  2. Development of the ventromedial nucleus of the hypothalamus.

    PubMed

    McClellan, Kristy M; Parker, Keith L; Tobet, Stuart

    2006-07-01

    The ventromedial nucleus of the hypothalamus (VMH) is important in the regulation of female sexual behavior, feeding, energy balance, and cardiovascular function. It is a highly conserved nucleus across species and a good model for studying neuronal organization into nuclei. Expression of various transcription factors, receptors, and neurotransmitters are important for the development of this nucleus and for mapping the position of identified cells within the nucleus. The VMH is subdivided into regions, all of which may project to specific locations to carry out various functions. For example, the ventrolateral quadrant contains a subset of neurons that highly express estrogen receptors. These neurons specifically are involved in the lordosis response pathway through projections to other estrogen receptor containing regions. In development, neurons that form the VMH generate from the proliferative zone surrounding the third ventricle. Neurons then migrate along radial glial fibers to final positions within the nucleus. Migration and positioning of neurons is an important step in setting up connections to and from the VMH and hence in its function. As compared to other developing brain regions, cell death may play a minor role in sculpting the VMH. We review the processes involved in forming a functional nuclear group and some of the factors known to be involved particularly focusing on the positioning of identified neurons within the VMH.

  3. Recent Developments in Neutrino/Antineutrino-Nucleus Interactions

    DOE PAGES

    Morfín, Jorge G.; Nieves, Juan; Sobczyk, Jan T.

    2012-01-01

    Recent experimental results and developments in the theoretical treatment of neutrino-nucleus interactions in the energy range of 1–10 GeV are discussed. Difficulties in extracting neutrino-nucleon cross sections from neutrino-nucleus scattering data are explained and significance of understanding nuclear effects for neutrino oscillation experiments is stressed. Detailed discussions of the status of two-body current contribution in the kinematic region dominated by quasielastic scattering and specific features of partonic nuclear effects in weak DIS scattering are presented.

  4. Recent Developments in Neutrino/Antineutrino-Nucleus Interactions

    SciTech Connect

    Morfín, Jorge G.; Nieves, Juan; Sobczyk, Jan T.

    2012-01-01

    Recent experimental results and developments in the theoretical treatment of neutrino-nucleus interactions in the energy range of 1–10 GeV are discussed. Difficulties in extracting neutrino-nucleon cross sections from neutrino-nucleus scattering data are explained and significance of understanding nuclear effects for neutrino oscillation experiments is stressed. Detailed discussions of the status of two-body current contribution in the kinematic region dominated by quasielastic scattering and specific features of partonic nuclear effects in weak DIS scattering are presented.

  5. A method for measuring coherent elastic neutrino-nucleus scattering at a far off-axis high-energy neutrino beam target

    SciTech Connect

    Brice, S. J.; Cooper, R. L.; DeJongh, F.; Empl, A.; Garrison, L. M.; Hime, A.; Hungerford, E.; Kobilarcik, T.; Loer, B.; Mariani, C.; Mocko, M.; Muhrer, G.; Pattie, R.; Pavlovic, Z.; Ramberg, E.; Scholberg, K.; Tayloe, R.; Thornton, R. T.; Yoo, J.; Young, A.

    2014-04-03

    We present an experimental method for measuring the process of coherent elastic neutrino-nucleus scattering (CENNS). This method uses a detector situated transverse to a high-energy neutrino beam production target. This detector would be sensitive to the low-energy neutrinos arising from decay-at-rest pions in the target. We discuss the physics motivation for making this measurement and outline the predicted backgrounds and sensitivities using this approach. We report a measurement of neutron backgrounds as found in an off-axis surface location of the Fermilab Booster Neutrino Beam (BNB) target. The results indicate that the Fermilab BNB target is a favorable location for a CENNS experiment.

  6. Empirical description of the hadron-hadron and hadron-nucleus interaction at the accelerator energy range

    NASA Technical Reports Server (NTRS)

    Kubiak, G.; Szabelski, J.; Wdowczyk, J.; Kempa, J.; Piotrowska, A.

    1985-01-01

    Taking into account several assumptions, a formula is transformed into two expressions for kaon and baryon plus antibaryon production in proton interaction and for pion production in pion interactions. Combining both formulae, expression are obtained for the spectrum of kaons and baryons plus antibaryons produced in the meson interactions. For analysis of the cosmic ray propagation in the atmosphere in actual fact, instead of the formulae for interactions of protons and mesons with protons, formulae appropriate for interactions with air nuclei was used. Using the method outlined among others by Elias et al. (1980) simple corrections were introduced to the derived expressions to account for the fact that the target is an air nucleus.

  7. The Neutrophil Nucleus and Its Role in Neutrophilic Function.

    PubMed

    Carvalho, Leonardo Olivieri; Aquino, Elaine Nascimento; Neves, Anne Caroline Dias; Fontes, Wagner

    2015-09-01

    The cell nucleus plays a key role in differentiation processes in eukaryotic cells. It is not the nucleus in particular, but the organization of the genes and their remodeling that provides the data for the adjustments to be made according to the medium. The neutrophil nucleus has a different morphology. It is a multi-lobed nucleus where some researchers argue no longer function. However, studies indicate that it is very probable the occurrence of chromatin remodeling during activation steps. It may be that the human neutrophil nucleus also contributes to the mobility of neutrophils through thin tissue spaces. Questions like these will be discussed in this small review. The topics include morphology of human neutrophil nucleus, maturation process and modifications of the neutrophil nucleus, neutrophil activation and chromatin modifications, causes and consequences of multi-lobulated segmented morphology, and importance of the nucleus in the formation of neutrophil extracellular traps (NETs).

  8. Why do we have a caudate nucleus?

    PubMed

    Villablanca, Jaime R

    2010-01-01

    In order to understand the physiological role of the caudate nucleus, we combine here our laboratory data on cats with reports of patients with selective damage to this nucleus. Cats with bilateral removal of the caudate nuclei showed a stereotyped behavior consisting of persistently approaching and then following a person, another cat, or any object, and attempting to contact the target. Simultaneously, the animals exhibited a friendly disposition and persistent docility together with purring and forelimbs treading/kneading. The magnitude and duration of this behavior was proportional to the extent of the removal reaching a maximum after ablations of 65% or more of the caudate tissue. These cats were hyperactive but they had lost the feline elegance of movements. Additional features of acaudate cats were: (1) postural and accuracy deficits (plus perseveration) in paw usage tasks including bar pressing for food reward; (2) cognitive and perceptual impairments on a T-maze battery of tasks and on the bar pressing tasks; (3) blockage or blunting of the species-specific behavioral response to a single injection of morphine; Unilateral caudate nucleus removal did not produce global behavioral effects, but only deficit in the contralateral paw contact placing reaction and paw usage/bar pressing. Moreover and surprisingly, we found hypertrophy of the ipsilateral caudate nucleus following prenatal focal neocortical removal. The findings in human were also behavioral (not neurological) and also occurred with unilateral caudate damage. The main manifestations consisted of loss of drive (apathy), obsessive-compulsive behavior, cognitive deficits, stimulus-bound perseverative behavior, and hyperactivity. Based on all of the above data we propose that the specific function of the caudate nucleus is to control approach-attachment behavior, ranging from plain approach to a target, to romantic love. This putative function would account well for the caudate involvement in the

  9. Collateral projections from the lateral parabrachial nucleus to the paraventricular thalamic nucleus and the central amygdaloid nucleus in the rat.

    PubMed

    Liang, Shao-Hua; Yin, Jun-Bin; Sun, Yi; Bai, Yang; Zhou, Kai-Xiang; Zhao, Wen-Jun; Wang, Wei; Dong, Yu-Lin; Li, Yun-Qing

    2016-08-26

    Combined the retrograde double tracing with immunofluorescence histochemical staining, we examined the neurons in the lateral parabrachial nucleus (LPB) sent collateral projections to the paraventricular thalamic nucleus (PVT) and central amygdaloid nucleus (CeA) and their roles in the nociceptive transmission in the rat. After the injection of Fluoro-gold (FG) into the PVT and tetramethylrhodamine-dextran (TMR) into the CeA, respectively, FG/TMR double-labeled neurons were observed in the LPB. The percentages of FG/TMR double-labeled neurons to the total number of FG- or TMR-labeled neurons were 6.18% and 9.09%, respectively. Almost all of the FG/TMR double-labeled neurons (95%) exhibited calcitonin gene-related peptide (CGRP) immunoreactivity. In the condition of neuropathic pain, 94% of these neurons showed FOS immunoreactivity. The present data indicates that some of CGRP-expressing neurons in the LPB may transmit nociceptive information toward the PVT and CeA by way of axon collaterals.

  10. Measuring neutrino-nucleus interactions with MINERνA

    SciTech Connect

    Rodrigues, P. A.

    2015-07-15

    We present results from the MINERνA experiment for neutrino-nucleus scattering in the few-GeV energy region. These measurements cover a range of processes that must be modeled correctly in neutrino oscillation experiments, and in which recent results from other experiments have suggested deficiencies in the models currently used.

  11. Observation of the antimatter helium-4 nucleus

    SciTech Connect

    Agakishiev, H.; Tang, A.; et al.

    2011-04-24

    High-energy nuclear collisions create an energy density similar to that of the Universe microseconds after the Big Bang; in both cases, matter and antimatter are formed with comparable abundance. However, the relatively short-lived expansion in nuclear collisions allows antimatter to decouple quickly from matter, and avoid annihilation. Thus, a high-energy accelerator of heavy nuclei provides an efficient means of producing and studying antimatter. The antimatter helium-4 nucleus ({sup 4}He), also known as the anti-{alpha} ({alpha}), consists of two antiprotons and two antineutrons (baryon number B = -4). It has not been observed previously, although the {alpha}-particle was identified a century ago by Rutherford and is present in cosmic radiation at the ten per cent level. Antimatter nuclei with B < -1 have been observed only as rare products of interactions at particle accelerators, where the rate of antinucleus production in high-energy collisions decreases by a factor of about 1,000 with each additional antinucleon. Here we report the observation of {sup 4}He, the heaviest observed antinucleus to date. In total, 18 {sup 4}He counts were detected at the STAR experiment at the Relativistic Heavy Ion Collider (RHIC) in 10{sup 9} recorded gold-on-gold (Au+Au) collisions at centre-of-mass energies of 200 GeV and 62 GeV per nucleon-nucleon pair. The yield is consistent with expectations from thermodynamic and coalescent nucleosynthesis models, providing an indication of the production rate of even heavier antimatter nuclei and a benchmark for possible future observations of {sup 4}He in cosmic radiation.

  12. Statistical analysis of secondary particle distributions in relativistic nucleus-nucleus collisions

    NASA Technical Reports Server (NTRS)

    Mcguire, Stephen C.

    1987-01-01

    The use is described of several statistical techniques to characterize structure in the angular distributions of secondary particles from nucleus-nucleus collisions in the energy range 24 to 61 GeV/nucleon. The objective of this work was to determine whether there are correlations between emitted particle intensity and angle that may be used to support the existence of the quark gluon plasma. The techniques include chi-square null hypothesis tests, the method of discrete Fourier transform analysis, and fluctuation analysis. We have also used the method of composite unit vectors to test for azimuthal asymmetry in a data set of 63 JACEE-3 events. Each method is presented in a manner that provides the reader with some practical detail regarding its application. Of those events with relatively high statistics, Fe approaches 0 at 55 GeV/nucleon was found to possess an azimuthal distribution with a highly non-random structure. No evidence of non-statistical fluctuations was found in the pseudo-rapidity distributions of the events studied. It is seen that the most effective application of these methods relies upon the availability of many events or single events that possess very high multiplicities.

  13. Quantitative analysis of the fusion cross sections using different microscopic nucleus-nucleus interactions

    NASA Astrophysics Data System (ADS)

    Adel, A.; Alharbi, T.

    2017-01-01

    The fusion cross sections for reactions involving medium and heavy nucleus-nucleus systems are investigated near and above the Coulomb barrier using the one-dimensional barrier penetration model. The microscopic nuclear interaction potential is computed by four methods, namely: the double-folding model based on a realistic density-dependent M3Y NN interaction with a finite-range exchange part, the Skyrme energy density functional in the semiclassical extended Thomas-Fermi approximation, the generalized Proximity potential, and the Akyüz-Winther interaction. The comparison between the calculated and the measured values of the fusion excitation functions indicates that the calculations of the DFM give quite satisfactory agreement with the experimental data, being much better than the other methods. New parameterized forms for the fusion barrier heights and positions are presented. Furthermore, the effects of deformation and orientation degrees of freedom on the distribution of the Coulomb barrier characteristics as well as the fusion cross sections are studied for the reactions 16 O + 70 Ge and 28 Si + 100 Mo. The calculated values of the total fusion cross sections are compared with coupled channel calculations using the code CCFULL and compared with the experimental data. Our results reveal that the inclusion of deformations and orientation degrees of freedom improves the comparison with the experimental data.

  14. Cell Nucleus-Targeting Zwitterionic Carbon Dots

    PubMed Central

    Jung, Yun Kyung; Shin, Eeseul; Kim, Byeong-Su

    2015-01-01

    An innovative nucleus-targeting zwitterionic carbon dot (CD) vehicle has been developed for anticancer drug delivery and optical monitoring. The zwitterionic functional groups of the CDs introduced by a simple one-step synthesis using β-alanine as a passivating and zwitterionic ligand allow cytoplasmic uptake and subsequent nuclear translocation of the CDs. Moreover, multicolor fluorescence improves the accuracy of the CDs as an optical code. The CD-based drug delivery system constructed by non-covalent grafting of doxorubicin, exhibits superior antitumor efficacy owing to enhanced nuclear delivery in vitro and tumor accumulation in vivo, resulting in highly effective tumor growth inhibition. Since the zwitterionic CDs are highly biocompatible and effectively translocated into the nucleus, it provides a compelling solution to a multifunctional nanoparticle for substantially enhanced nuclear uptake of drugs and optical monitoring of translocation. PMID:26689549

  15. Gustatory Reward and the Nucleus Accumbens

    PubMed Central

    Norgren, R.; Hajnal, A.; Mungarndee, S.S.

    2011-01-01

    The concept of reward is central to psychology, but remains a cipher for neuroscience. Considerable evidence implicates dopamine in the process of reward and much of the data derives from the nucleus accumbens. Gustatory stimuli are widely used for animal studies of reward, but the connections between the taste and reward systems are unknown. In a series of experiments, our laboratory has addressed this issue using functional neurochemistry and neuroanatomy. First, using microdialysis probes, we demonstrated that sapid sucrose releases dopamine in the nucleus accumbens. The effect is dependent on oral stimulation and concentration. We subsequently determined that this response was independent of the thalamocortical gustatory system, but substantially blunted by damage to the parabrachial limbic taste projection. Further experiments using c-fos histochemistry confirmed that the limbic pathway was the prime carrier for the gustatory afferent activity that drives accumbens dopamine release. PMID:16822531

  16. Cell Nucleus-Targeting Zwitterionic Carbon Dots.

    PubMed

    Jung, Yun Kyung; Shin, Eeseul; Kim, Byeong-Su

    2015-12-22

    An innovative nucleus-targeting zwitterionic carbon dot (CD) vehicle has been developed for anticancer drug delivery and optical monitoring. The zwitterionic functional groups of the CDs introduced by a simple one-step synthesis using β-alanine as a passivating and zwitterionic ligand allow cytoplasmic uptake and subsequent nuclear translocation of the CDs. Moreover, multicolor fluorescence improves the accuracy of the CDs as an optical code. The CD-based drug delivery system constructed by non-covalent grafting of doxorubicin, exhibits superior antitumor efficacy owing to enhanced nuclear delivery in vitro and tumor accumulation in vivo, resulting in highly effective tumor growth inhibition. Since the zwitterionic CDs are highly biocompatible and effectively translocated into the nucleus, it provides a compelling solution to a multifunctional nanoparticle for substantially enhanced nuclear uptake of drugs and optical monitoring of translocation.

  17. Physical Properties of Cometary Nucleus Candidates

    NASA Technical Reports Server (NTRS)

    Jewitt, David; Hillman, John (Technical Monitor)

    2003-01-01

    In this proposal we aim to study the physical properties of the Centaurs and the dead comets, these being the precursors to, and the remnants from, the active cometary nuclei. The nuclei themselves are very difficult to study, because of the contaminating effects of near-nucleus coma. Systematic investigation of the nuclei both before they enter the zone of strong sublimation and after they have depleted their near-surface volatiles should neatly bracket the properties of these objects, revealing evolutionary effects.

  18. Absolute cross sections of compound nucleus reactions

    NASA Astrophysics Data System (ADS)

    Capurro, O. A.

    1993-11-01

    The program SEEF is a Fortran IV computer code for the extraction of absolute cross sections of compound nucleus reactions. When the evaporation residue is fed by its parents, only cumulative cross sections will be obtained from off-line gamma ray measurements. But, if one has the parent excitation function (experimental or calculated), this code will make it possible to determine absolute cross sections of any exit channel.

  19. Development of a Mobile Ice Nucleus Counter

    SciTech Connect

    Kok, Gregory; Kulkarni, Gourihar

    2014-07-10

    An ice nucleus counter has been constructed. The instrument uses built-in refrigeration systems for wall cooling. A cascade refrigeration system will allow the cold wall to operate as low as -70°C, and a single stage system can operate the warm wall at -45C. A unique optical particle counter has been constructed using polarization detection of the scattered light. This allows differentiation of the particles exiting the chamber to determine if they are ice or liquid.

  20. How to build a yeast nucleus.

    PubMed

    Wong, Hua; Arbona, Jean-Michel; Zimmer, Christophe

    2013-01-01

    Biological functions including gene expression and DNA repair are affected by the 3D architecture of the genome, but the underlying mechanisms are still unknown. Notably, it remains unclear to what extent nuclear architecture is driven by generic physical properties of polymers or by specific factors such as proteins binding particular DNA sequences. The budding yeast nucleus has been intensely studied by imaging and biochemical techniques, resulting in a large quantitative data set on locus positions and DNA contact frequencies. We recently described a quantitative model of the interphase yeast nucleus in which chromosomes are represented as passively moving polymer chains. This model ignores the DNA sequence information except for specific constraints at the centromeres, telomeres, and the ribosomal DNA (rDNA). Despite its simplicity, the model accounts for a large majority of experimental data, including absolute and relative locus positions and contact frequency patterns at chromosomal and subchromosomal scales. Here, we also illustrate the model's ability to reproduce observed features of chromatin movements. Our results strongly suggest that the dynamic large-scale architecture of the yeast nucleus is dominated by statistical properties of randomly moving polymers with a few sequence-specific constraints, rather than by a large number of DNA-specific factors or epigenetic modifications. In addition, we show that our model accounts for recently measured variations in homologous recombination efficiency, illustrating its potential for quantitatively understanding functional consequences of nuclear architecture.

  1. Comet nucleus and asteroid sample return missions

    NASA Astrophysics Data System (ADS)

    1992-06-01

    Three Advanced Design Projects have been completed this academic year at Penn State. At the beginning of the fall semester the students were organized into eight groups and given their choice of either a comet nucleus or an asteroid sample return mission. Once a mission had been chosen, the students developed conceptual designs. These were evaluated at the end of the fall semester and combined into three separate mission plans, including a comet nucleus same return (CNSR), a single asteroid sample return (SASR), and a multiple asteroid sample return (MASR). To facilitate the work required for each mission, the class was reorganized in the spring semester by combining groups to form three mission teams. An integration team consisting of two members from each group was formed for each mission so that communication and information exchange would be easier among the groups. The types of projects designed by the students evolved from numerous discussions with Penn State faculty and mission planners at the Johnson Space Center Human/Robotic Spacecraft Office. Robotic sample return missions are widely considered valuable precursors to manned missions in that they can provide details about a site's environment and scientific value. For example, a sample return from an asteroid might reveal valuable resources that, once mined, could be utilized for propulsion. These missions are also more adaptable when considering the risk to humans visiting unknown and potentially dangerous locations, such as a comet nucleus.

  2. Comet nucleus and asteroid sample return missions

    NASA Technical Reports Server (NTRS)

    1992-01-01

    Three Advanced Design Projects have been completed this academic year at Penn State. At the beginning of the fall semester the students were organized into eight groups and given their choice of either a comet nucleus or an asteroid sample return mission. Once a mission had been chosen, the students developed conceptual designs. These were evaluated at the end of the fall semester and combined into three separate mission plans, including a comet nucleus same return (CNSR), a single asteroid sample return (SASR), and a multiple asteroid sample return (MASR). To facilitate the work required for each mission, the class was reorganized in the spring semester by combining groups to form three mission teams. An integration team consisting of two members from each group was formed for each mission so that communication and information exchange would be easier among the groups. The types of projects designed by the students evolved from numerous discussions with Penn State faculty and mission planners at the Johnson Space Center Human/Robotic Spacecraft Office. Robotic sample return missions are widely considered valuable precursors to manned missions in that they can provide details about a site's environment and scientific value. For example, a sample return from an asteroid might reveal valuable resources that, once mined, could be utilized for propulsion. These missions are also more adaptable when considering the risk to humans visiting unknown and potentially dangerous locations, such as a comet nucleus.

  3. Forward Physics in Proton-Nucleus and Nucleus-Nucleus Collisions

    SciTech Connect

    Nemchik, J.; Potashnikova, I. K.

    2008-10-13

    We present an universal treatment for a substantial nuclear suppression representing a common feature of all known reactions on nuclear targets (forward production of high-p{sub T} hadrons, production of direct photons, the Drell-Yan process, heavy flavor production, etc.). Such a suppression at large Feynman x{sub F}, corresponding to region of minimal light-cone momentum fraction variable x{sub 2} in nuclei, is tempting to interpret as a manifestation of coherence or the Color Glass Condensate. We demonstrate, however, that it is actually a simple consequence of energy conservation and takes place even at low energies, where no effects of coherence are possible. We analyze this common suppression mechanism for several processes performing model predictions in the light-cone dipole approach. Our calculations agree with the data.

  4. Dynamical evolution of comet nucleus rotation

    NASA Astrophysics Data System (ADS)

    Scheeres, D. J.; Sidorenko, V. V.; Neishtadt, A. I.; Vasiliev, A. A.

    2002-09-01

    The rotational dynamics of outgassing cometary nuclei are investigated analytically. We develop a general theory for the evolution of a comet nucleus' rotation state using averaging theory and assuming that the outgassing torques are a function of solar insolation and heliocentric distance. The resulting solutions are a function of the nucleus inertia ellipsoid, its outgassing properties, its heliocentric orbit, and the assumed distribution of active regions on its surface. We find that the long-term evolution of the comet nucleus rotation is a strong function of the distribution of active regions over its surface. In particular, we find that nuclei with nearly axisymmetric inertia ellipsoids and a uniformly active surface will tend towards a rotation state that has a nutation angle of ~ 55 degrees and its angular momentum perpendicular to the sun-perihelion direction. If such a comet nucleus has only one isolated active region, it will tend towards a zero nutation angle with its approximate symmetry axis and rotational angular momentum aligned parallel to the sun-perihelion direction. In the general case for an inertia ellipsoid that is not close to being axisymmetric we find a much richer set of possible steady-state solutions that are stable, ranging from rotation about the maximum moment of the inertia axis, to SAM and LAM non-principal axis rotation states. The resulting stable rotation states are a strong function of outgassing activity distribution, which we show using a simplified model of the comet Halley nucleus. Also, we demonstrate that comet Borrely observations are consistent with a stable rotation state. Our results can be used to discriminate between competing theories of comet outgassing based on a nucelus' rotation state. They also allow for a range of plausible a priori constraints to be placed on a comet's rotation state to aid in the interpretation of its outgassing structure. This work was supported by the NASA JURRISS program under Grant NAG5

  5. Dynamics of strange, charm and high momentum hadrons in relativistic nucleus-nucleus collisions

    NASA Astrophysics Data System (ADS)

    Cassing, W.; Gallmeister, K.; Bratkovskaya, E. L.; Greiner, C.; Stöcker, H.

    2004-07-01

    We investigate hadron production and attenuation of hadrons with strange and charm quarks (or antiquarks) as well as high transverse momentum hadrons in relativistic nucleus-nucleus collisions from 2 A GeV to 21.3 A TeV within two independent transport approaches (UrQMD and HSD). Both transport models are based on quark, diquark, string and hadronic degrees of freedom, but do not include any explicit phase transition to a quark-gluon plasma. From our dynamical calculations we find that both models do not describe the maximum in the K+/ π+ ratio at 20-30 A GeV in central Au+Au collisions found experimentally, though the excitation functions of strange mesons are reproduced well in HSD and UrQMD. Furthermore, the transport calculations show that the charmonium recreation by D+ D¯→J/Ψ+ meson reactions is comparable to the dissociation by ‘comoving’ mesons at RHIC energies contrary to SPS energies. This leads to the final result that the total J/ Ψ suppression as a function of centrality at RHIC should be less than the suppression seen at SPS energies where the ‘comover’ dissociation is substantial and the backward channels play no role. Furthermore, our transport calculations-in comparison to experimental data on transverse momentum spectra from pp, d+Au and Au+Au reactions-show that pre-hadronic effects are responsible for both the hardening of the hadron spectra for low transverse momenta (Cronin effect) as well as the suppression of high pT hadrons. The mutual interactions of formed hadrons are found to be negligible in central Au+Au collisions at s=200 GeV for p T≥6 GeV/c and the sizeable suppression seen experimentally is attributed to a large extent to the interactions of ‘leading’ pre-hadrons with the dense environment.

  6. Biological Effect of Lead-212 Localized in the Nucleus of Mammalian Cells: Role of Recoil Energy in the Radiotoxicity of Internal Alpha-Particle Emitters1

    PubMed Central

    Azure, Michael T.; Archer, Ronald D.; Sastry, Kandula S. R.; Rao, Dandamudi V.; Howell, Roger W.

    2012-01-01

    The radiochemical dipyrrolidinedithiocarbamato-212Pb(II) [212Pb(PDC)2] is synthesized and its effects on colony formation in cultured Chinese hamster V79 cells are investigated. The cellular uptake, biological retention, subcellular distribution and cytotoxicity of the radiocompound are determined. The 212Pb is taken up quickly by the cells, reaching saturation levels in 1.25 h. When the cells are washed, the intracellular activity is retained with a biological half-life of 11.6 h. Gamma-ray spectroscopy indicates that the 212Pb daughters (212Bi, 212Po and 208Tl) are in secular equilibrium within the cell. About 72% of the cellular activity localizes in the cell nucleus, of which 35% is bound specifically to nuclear DNA. The mean cellular uptake required to achieve 37% survival is 0.35 mBq of 212Pb per cell, which delivers a dose of 1.0 Gy to the cell nucleus when the recoil energy of 212Bi and 212Po decays is ignored and 1.7 Gy when recoil is included. The corresponding RBE values compared to acute external 137Cs γ rays at 37% survival are 4.0 and 2.3, respectively. The chemical Pb(PDC)2 is not chemotoxic at the concentrations used in this study. Because the β-particle emitter 212Pb decays to the α-particle-emitting daughters 212Bi and 212Po, these studies provide information on the biological effects of α-particle decays that occur in the cell nucleus. Our earlier studies with cells of the same cell line using 210Po (emits 5.3 MeV α particle) localized predominantly in the cytoplasm resulted in an RBE of 6. These earlier results for 210Po, along with the present results for 212Pb, suggest that the recoil energy associated with the 212Bi and 212Po daughter nuclei plays little or no role in imparting biological damage to critical targets in the cell nucleus. PMID:7938477

  7. Nucleus-nucleus cold fusion reactions analyzed with the l-dependent 'fusion by diffusion' model

    SciTech Connect

    Cap, T.; Siwek-Wilczynska, K.; Wilczynski, J.

    2011-05-15

    We present a modified version of the Fusion by Diffusion (FBD) model aimed at describing the synthesis of superheavy nuclei in cold fusion reactions, in which a low excited compound nucleus emits only one neutron. The modified FBD model accounts for the angular momentum dependence of three basic factors determining the evaporation residue cross section: the capture cross section {sigma}{sub cap}(l), the fusion probability P{sub fus}(l), and the survival probability P{sub surv}(l). The fusion hindrance factor, the inverse of P{sub fus}(l), is treated in terms of thermal fluctuations in the shape degrees of freedom and is expressed as a solution of the Smoluchowski diffusion equation. The l dependence of P{sub fus}(l) results from the l-dependent potential energy surface of the colliding system. A new parametrization of the distance of starting point of the diffusion process is introduced. An analysis of a complete set of 27 excitation functions for production of superheavy nuclei in cold fusion reactions, studied in experiments at GSI Darmstadt, RIKEN Tokyo, and LBNL Berkeley, is presented. The FBD model satisfactorily reproduces shapes and absolute cross sections of all the cold fusion excitation functions. It is shown that the peak position of the excitation function for a given 1n reaction is determined by the Q value of the reaction and the height of the fission barrier of the final nucleus. This fact could possibly be used in future experiments (with well-defined beam energy) for experimental determination of the fission barrier heights.

  8. Nuclear radii calculations in various theoretical approaches for nucleus-nucleus interactions

    SciTech Connect

    Merino, C.; Novikov, I. S.; Shabelski, Yu.

    2009-12-15

    The information about sizes and nuclear density distributions in unstable (radioactive) nuclei is usually extracted from the data on interaction of radioactive nuclear beams with a nuclear target. We show that in the case of nucleus-nucleus collisions the values of the parameters depend somewhat strongly on the considered theoretical approach and on the assumption about the parametrization of the nuclear density distribution. The obtained values of root-mean-square radii (R{sub rms}) for stable nuclei with atomic weights A=12-40 vary by approximately 0.1 fm when calculated in the optical approximation, in the rigid target approximation, and using the exact expression of the Glauber theory. We present several examples of R{sub rms} radii calculations using these three theoretical approaches and compare these results with the data obtained from electron-nucleus scattering.

  9. Electromagnetic processes in nucleus-nucleus collisions relating to space radiation research

    NASA Technical Reports Server (NTRS)

    Norbury, John W.

    1992-01-01

    Most of the papers within this report deal with electromagnetic processes in nucleus-nucleus collisions which are of concern in the space radiation program. In particular, the removal of one and two nucleons via both electromagnetic and strong interaction processes has been extensively investigated. The theory of relativistic Coulomb fission has also been developed. Several papers on quark models also appear. Finally, note that the theoretical methods developed in this work have been directly applied to the task of radiation protection of astronauts. This has been done by parameterizing the theoretical formalism in such a fashion that it can be used in cosmic ray transport codes.

  10. Surface Photometric Variation of Comet Borrelly's Nucleus

    NASA Astrophysics Data System (ADS)

    Li, J.; A'Hearn, M. F.; McFadden, L. A.

    2004-11-01

    Comet Borrelly was visited by Deep Space 1 in Sept. 2001 (Soderblom et al. 2004) The images of comet Borrelly's nucleus show large brightness variation over the surface even after the effect of shape is taken into account (Oberst et al. 2004, Kirk et al. 2004). It is not yet known whether this variation is caused by albedo variation (Oberst et al. 2004, Buratti et al. 2004) or the variation of other physical properties such as surface roughness (Kirk et al. 2004) or solar phase function. In our analysis, the disk-resolved images from the DS1 spacecraft (Soderblom et al. 2004) were used, coupled with the shape model of Borrelly's nucleus developed from stereo imaging (Oberst et al. 2004, Kirk et al. 2004), to fit the bidirectional reflectance as a function of local illumination and viewing geometry for individual terrains as defined by Britt et al. (2004). Results show that the surface reflectance variation is, contrary to previous interpretations, most likely due to the combination of albedo variation (a factor of 1.5) and the variation of the asymmetry factor (g) of the single-particle phase function. We find the roughness parameter (theta_bar) is <25o over the surface. The surface on Borrelly's nucleus can be highly back-scattering (g <= -0.7) for mottled terrain, and close to isotropic scattering (g -0.15) for smooth terrain, with single scattering albedo ranging from 0.05 to 0.07. This work is supported by NASA grant NNG04GA92G.

  11. Dust activity of Comet Halley's nucleus

    NASA Technical Reports Server (NTRS)

    Keller, H. U.; Delamere, W. A.; Huebner, W. F.; Reitsema, H.; Schmidt, H. U.; Schmidt, W. K. H.; Whipple, Fred L.; Wilhelm, K.

    1986-01-01

    Images obtained by the Halley multicolor camera using the clear filter with a pass band from 300 to 1000 nm were used to study dust activity in the comet nucleus. Comparisons with ground based observations confirm that dust production towards the Sun increases in activity relative to the southern background source while the Giotto spacecraft was approaching. This is in agreement with the assumption that the sunward activity becomes stronger when the source rotates towards the Sun. Estimated dust column density is 90 billion/sqm, with optical thickness less than or = 0.3. Surface reflectivity is less than 1%, indicating a very rough surface with large fractions of shadowed areas.

  12. [The perichromatin compartment of the cell nucleus].

    PubMed

    Bogoliubov, D S

    2014-01-01

    In this review, the data on the structure and composition of the perichromatin compartment, a special border area between the condensed chromatin and the interchromatin space of the cell nucleus, are discussed in the light of the concept of nuclear functions in complex nuclear architectonics. Morphological features, molecular composition and functions of main extrachromosomal structures of the perichromatin compartment, perichromatin fibrils (PFs) and perichromatin granules (PGs) including nuclear stress-bodies (nSBs) that are derivates of the PGs under heat shock, are presented. A special attention was paid to the features of the molecular compositions of PFs and PGs in different cell types and at different physiological conditions.

  13. The quasirelativistic contact interaction and effective electron and spin densities at the nucleus: A model based on weighting the electron density with the finite Gaussian nucleus model

    NASA Astrophysics Data System (ADS)

    Malček, Michal; Bučinský, Lukáš; Biskupič, Stanislav; Jayatilaka, Dylan

    2013-08-01

    The Infinite Order Two Component quasirelativistic Hartree-Fock contact and effective electron/spin densities of Cu, Ag, Au atoms and the chemical shifts of HgF2, Cu+, Ag+ and Au+ are presented. The effective densities for the Gaussian nucleus model based on the weighted product of electron/spin density with the Gaussian distribution of the nucleus are reported for the first time. The effective (average) electron density obtained via the derivative of the energy of the system with respect to the size of the nucleus is shown for comparison. The finite-field difference method to obtain the derivative of the energy is also considered.

  14. K+-nucleus potentials from K+-nucleon amplitudes

    NASA Astrophysics Data System (ADS)

    Friedman, E.

    2016-10-01

    Optical potentials for K+-nucleus interactions are constructed from K+-nucleon amplitudes using recently developed algorithm based on K+-N kinematics in the nuclear medium. With the deep penetration of K+ mesons into the nucleus at momenta below 800 MeV / c it is possible to test this approach with greater sensitivity than hitherto done with K- and pions. The energy-dependence of experimental reaction and total cross sections on nuclei is better reproduced with this approach compared to fixed-energy amplitudes. The inclusion of Pauli correlations in the medium also improves the agreement between calculation and experiment. The absolute scale of the cross sections is reproduced very well for 6Li but for C, Si and Ca calculated cross sections are (23 ± 4)% smaller than experiment, in agreement with earlier analyses. Two phenomenological models that produce such missing strength suggest that the imaginary part of the potential needs about 40% enhancement.

  15. Comet nucleus and asteroid sample return missions

    NASA Technical Reports Server (NTRS)

    Melton, Robert G.; Thompson, Roger C.; Starchville, Thomas F., Jr.; Adams, C.; Aldo, A.; Dobson, K.; Flotta, C.; Gagliardino, J.; Lear, M.; Mcmillan, C.

    1992-01-01

    During the 1991-92 academic year, the Pennsylvania State University has developed three sample return missions: one to the nucleus of comet Wild 2, one to the asteroid Eros, and one to three asteroids located in the Main Belt. The primary objective of the comet nucleus sample return mission is to rendezvous with a short period comet and acquire a 10 kg sample for return to Earth. Upon rendezvous with the comet, a tethered coring and sampler drill will contact the surface and extract a two-meter core sample from the target site. Before the spacecraft returns to Earth, a monitoring penetrator containing scientific instruments will be deployed for gathering long-term data about the comet. A single asteroid sample return mission to the asteroid 433 Eros (chosen for proximity and launch opportunities) will extract a sample from the asteroid surface for return to Earth. To limit overall mission cost, most of the mission design uses current technologies, except the sampler drill design. The multiple asteroid sample return mission could best be characterized through its use of future technology including an optical communications system, a nuclear power reactor, and a low-thrust propulsion system. A low-thrust trajectory optimization code (QuickTop 2) obtained from the NASA LeRC helped in planning the size of major subsystem components, as well as the trajectory between targets.

  16. Subthalamic Nucleus Stimulation Modulates Thalamic Neuronal Activity

    PubMed Central

    Xu, Weidong; Russo, Gary S.; Hashimoto, Takao; Zhang, Jianyu; Vitek, Jerrold L.

    2009-01-01

    Deep brain stimulation (DBS) in the subthalamic nucleus (STN) is an effective tool for the treatment of advanced Parkinson’s disease. The mechanism by which STN DBS elicits its beneficial effect, however, remains unclear. We previously reported STN stimulation increased the rate and produced a more regular and periodic pattern of neuronal activity in the internal segment of the globus pallidus (GPi). Here we extend our observations to neurons in the pallidal (ventralis lateralis pars oralis (VLo) and ventralis anterior (VA)) and cerebellar (ventralis lateralis posterior pars oralis (VPLo)) receiving areas of the motor thalamus during STN DBS. Stimulation parameters that produced improvement in rigidity and bradykinesia resulted in changes in the pattern and power of oscillatory activity of neuronal activity that were similar in both regions of the motor thalamus. Neurons in both VA/VLo and VPLo tended to become more periodic and regular with a shift in oscillatory activity from low to high frequencies. Burst activity was reduced in VA/VLo, but was not significantly changed in VPLo. There was also a significant shift in the population of VA/VLo neurons that were inhibited during STN DBS, while VPLo neurons tended to be activated. These data are consistent with the hypothesis that STN DBS increases output from the nucleus and produces a change in the pattern and periodicity of neuronal activity in the basal ganglia thalamic network, and that these changes include cerebellar pathways likely via activation of adjacent cerebello-thalamic fiber bundles. PMID:19005057

  17. On M31's Double Nucleus

    NASA Technical Reports Server (NTRS)

    Miller, R. H.; Smith, B. F.; Cuzzi, Jeffrey (Technical Monitor)

    1995-01-01

    The recent HST discovery of a double nucleus in M31 brings into prominence the question how long, a second core can survive within the nuclear regions of a galaxy. Physical conditions in the nuclear regions of a typical galaxy help a second core survive, so it can orbit for a long time. possibly for thousands of orbits. Given the nearly uniform mass density in a core, tidal forces within a core radius are compressive in all directions and help the core survive the buffeting it takes as it orbits near the center of the galaxy. We use numerical experiments to illustrate these physical principles. Our method allows the full power of the experiments to be concentrated on the nuclear regions. Spatial resolution of about 0.2 pc comfortably resolves detail within the 1.4 parsec core radius of the second, but brighter core (P1) in M31. We use these physical principles to discuss M31's double nucleus, but they apply to other galaxies as well. and in other astronomical situations such as dumbbell galaxies. galaxies orbiting near the center of a galaxy cluster, and subclustering in galaxy clusters. The experiments also illustrate that galaxy encounters and merging are quite sensitive to external tidal forces, such as those produced by the gravitational potential in a group or cluster of galaxies.

  18. Spectrin repeat proteins in the nucleus.

    PubMed

    Young, Kevin G; Kothary, Rashmi

    2005-02-01

    Spectrin repeat sequences are among the more common repeat elements identified in proteins, typically occurring in large structural proteins. Examples of spectrin repeat-containing proteins include dystrophin, alpha-actinin and spectrin itself--all proteins with well-demonstrated roles of establishing and maintaining cell structure. Over the past decade, it has become clear that, although these proteins display a cytoplasmic and plasma membrane distribution, several are also found both at the nuclear envelope, and within the intranuclear space. In this review, we provide an overview of recent work regarding various spectrin repeat-containing structural proteins in the nucleus. As well, we hypothesize about the regulation of their nuclear localization and possible nuclear functions based on domain architecture, known interacting proteins and evolutionary relationships. Given their large size, and their potential for interacting with multiple proteins and with chromatin, spectrin repeat-containing proteins represent strong candidates for important organizational proteins within the nucleus. Supplementary material for this article can be found on the BioEssays website (http://www.interscience.wiley.com/jpages/0265-9247/suppmat/index.html).

  19. A Simple Method for Nucleon-Nucleon Cross Sections in a Nucleus

    NASA Technical Reports Server (NTRS)

    Tripathi, R. K.; Cucinotta, Francis A.; Wilson, John W.

    1999-01-01

    A simple reliable formalism is presented for obtaining nucleon-nucleon cross sections within a nucleus in nuclear collisions for a given projectile and target nucleus combination at a given energy for use in transport, Monte Carlo, and other calculations. The method relies on extraction of these values from experiments and has been tested and found to give excellent results.

  20. PREFACE: 11th International Conference on Nucleus-Nucleus Collisions (NN2012)

    NASA Astrophysics Data System (ADS)

    Li, Bao-An; Natowitz, Joseph B.

    2013-03-01

    The 11th International Conference on Nucleus-Nucleus Collisions (NN2012) was held from 27 May to 1 June 2012, in San Antonio, Texas, USA. It was jointly organized and hosted by The Cyclotron Institute at Texas A&M University, College Station and The Department of Physics and Astronomy at Texas A&M University-Commerce. Among the approximately 300 participants were a large number of graduate students and post-doctoral fellows. The Keynote Talk of the conference, 'The State of Affairs of Present and Future Nucleus-Nucleus Collision Science', was given by Dr Robert Tribble, University Distinguished Professor and Director of the TAMU Cyclotron Institute. During the conference a very well-received public lecture on neutrino astronomy, 'The ICEcube project', was given by Dr Francis Halzen, Hilldale and Gregory Breit Distinguished Professor at the University of Wisconsin, Madison. The Scientific program continued in the general spirit and intention of this conference series. As is typical of this conference a broad range of topics including fundamental areas of nuclear dynamics, structure, and applications were addressed in 42 plenary session talks, 150 parallel session talks, and 21 posters. The high quality of the work presented emphasized the vitality and relevance of the subject matter of this conference. Following the tradition, the NN2012 International Advisory Committee selected the host and site of the next conference in this series. The 12th International Conference on Nucleus-Nucleus Collisions (NN2015) will be held 21-26 June 2015 in Catania, Italy. It will be hosted by The INFN, Laboratori Nazionali del Sud, INFN, Catania and the Dipartimento di Fisica e Astronomia of the University of Catania. The NN2012 Proceedings contains the conference program and 165 articles organized into the following 10 sections 1. Heavy and Superheavy Elements 2. QCD and Hadron Physics 3. Relativistic Heavy-Ion Collisions 4. Nuclear Structure 5. Nuclear Energy and Applications of

  1. High-spin states in the 96Tc nucleus

    NASA Astrophysics Data System (ADS)

    Bucurescu, D.; Căta-Danil, Gh.; Căta-Danil, I.; Ivaşcu, M.; Mărginean, N.; Rusu, C.; Stroe, L.; Ur, C. A.; Gizon, A.; Gizon, J.; Nyakó, B.; Timár, J.; Zolnai, L.; Boston, A. J.; Joss, D. T.; Paul, E. S.; Semple, A. T.; Parry, C. M.

    High-spin states in the 96Tc nucleus have been studied with the reactions 82Se(19F,5nγ) at 68 MeV and Zn(36S,αpxn) at 130 MeV. Two γ-ray cascades (irregular bandlike structures) have been observed up to an excitation energy of about 10 MeV and spin 21-22?.

  2. High-spin states in the 97Tc nucleus

    NASA Astrophysics Data System (ADS)

    Bucurescu, D.; Gadea, A.; Căta-Danil, Ghe.; Căta-Danil, I.; Ivaşcu, M.; Mărginean, N.; Rusu, C.; Stroe, L.; Ur, C. A.

    High-spin states in the 97Tc nucleus have been studied by in-beam γ-ray spectroscopy with the reaction 82Se(19F,4nγ) at 68 MeV incident energy. Excited states have been observed up to about 8 MeV excitation and spin 43/2ℎ. The observed level scheme is compared with results of shell model calculations.

  3. Odyssey Comet Nucleus Orbiter: The Next Step in Cometary Exploration

    NASA Technical Reports Server (NTRS)

    Weissman, P. R.; Nilsen, E. N.; Smythe, W. D.; Marriott, J.; Reinert, R.

    2001-01-01

    Cometary nuclei are the most primitive bodies in the solar system, containing a cosmo-chemical record of the primordial solar nebula. Flyby missions to comets, such as those that encountered Comet Halley in 1986, provide a glimpse at this record. However, to study a cometary nucleus in detail requires a rendezvous mission, i.e., a nucleus orbiter. Only an orbiter provides the ability to map the entire nucleus surface at high resolution, to study the complex chemistry in the cometary coma and its variation with time, and to determine the mass and bulk density of the nucleus, key parameters in understanding how small bodies first formed in the solar nebula. A nucleus orbiter also provides the opportunity to sense the nucleus surface in preparation for more ambitious landing and sample return missions in the future. Additional information is contained in the original extended abstract.

  4. Defense of Elevated Body Weight Setpoint in Diet-Induced Obese Rats on Low Energy Diet Is Mediated by Loss of Melanocortin Sensitivity in the Paraventricular Hypothalamic Nucleus.

    PubMed

    Luchtman, Dirk W; Chee, Melissa J S; Doslikova, Barbora; Marks, Daniel L; Baracos, Vickie E; Colmers, William F

    2015-01-01

    Some animals and humans fed a high-energy diet (HED) are diet-resistant (DR), remaining as lean as individuals who were naïve to HED. Other individuals become obese during HED exposure and subsequently defend the obese weight (Diet-Induced Obesity- Defenders, DIO-D) even when subsequently maintained on a low-energy diet. We hypothesized that the body weight setpoint of the DIO-D phenotype resides in the hypothalamic paraventricular nucleus (PVN), where anorexigenic melanocortins, including melanotan II (MTII), increase presynaptic GABA release, and the orexigenic neuropeptide Y (NPY) inhibits it. After prolonged return to low-energy diet, GABA inputs to PVN neurons from DIO-D rats exhibited highly attenuated responses to MTII compared with those from DR and HED-naïve rats. In DIO-D rats, melanocortin-4 receptor expression was significantly reduced in dorsomedial hypothalamus, a major source of GABA input to PVN. Unlike melanocortin responses, NPY actions in PVN of DIO-D rats were unchanged, but were reduced in neurons of the ventromedial hypothalamic nucleus; in PVN of DR rats, NPY responses were paradoxically increased. MTII-sensitivity was restored in DIO-D rats by several weeks' refeeding with HED. The loss of melanocortin sensitivity restricted to PVN of DIO-D animals, and its restoration upon prolonged refeeding with HED suggest that their melanocortin systems retain the ability to up- and downregulate around their elevated body weight setpoint in response to longer-term changes in dietary energy density. These properties are consistent with a mechanism of body weight setpoint.

  5. In vitro and in silico investigations of disc nucleus replacement.

    PubMed

    Reitmaier, Sandra; Shirazi-Adl, Aboulfazl; Bashkuev, Maxim; Wilke, Hans-Joachim; Gloria, Antonio; Schmidt, Hendrik

    2012-08-07

    Currently, numerous hydrogels are under examination as potential nucleus replacements. The clinical success, however, depends on how well the mechanical function of the host structure is restored. This study aimed to evaluate the extent to and mechanisms by which surgery for nucleus replacements influence the mechanical behaviour of the disc. The effects of an annulus defect with and without nucleus replacement on disc height and nucleus pressure were measured using 24 ovine motion segments. The following cases were considered: intact; annulus incision repaired by suture and glue; annulus incision with removal and re-implantation of nucleus tissue repaired by suture and glue or plug. To identify the likely mechanisms observed in vitro, a finite-element model of a human disc (L4-L5) was employed. Both studies were subjected to physiological cycles of compression and recovery. A repaired annulus defect did not influence the disc behaviour in vitro, whereas additional nucleus removal and replacement substantially decreased disc stiffness and nucleus pressure. Model predictions demonstrated the substantial effects of reductions in replaced nucleus water content, bulk modulus and osmotic potential on disc height loss and pressure, similar to measurements. In these events, the compression load transfer in the disc markedly altered by substantially increasing the load on the annulus when compared with the nucleus. The success of hydrogels for nucleus replacements is not only dependent on the implant material itself but also on the restoration of the environment perturbed during surgery. The substantial effects on the disc response of disruptions owing to nucleus replacements can be simulated by reduced nucleus water content, elastic modulus and osmotic potential.

  6. In vitro and in silico investigations of disc nucleus replacement

    PubMed Central

    Reitmaier, Sandra; Shirazi-Adl, Aboulfazl; Bashkuev, Maxim; Wilke, Hans-Joachim; Gloria, Antonio; Schmidt, Hendrik

    2012-01-01

    Currently, numerous hydrogels are under examination as potential nucleus replacements. The clinical success, however, depends on how well the mechanical function of the host structure is restored. This study aimed to evaluate the extent to and mechanisms by which surgery for nucleus replacements influence the mechanical behaviour of the disc. The effects of an annulus defect with and without nucleus replacement on disc height and nucleus pressure were measured using 24 ovine motion segments. The following cases were considered: intact; annulus incision repaired by suture and glue; annulus incision with removal and re-implantation of nucleus tissue repaired by suture and glue or plug. To identify the likely mechanisms observed in vitro, a finite-element model of a human disc (L4–L5) was employed. Both studies were subjected to physiological cycles of compression and recovery. A repaired annulus defect did not influence the disc behaviour in vitro, whereas additional nucleus removal and replacement substantially decreased disc stiffness and nucleus pressure. Model predictions demonstrated the substantial effects of reductions in replaced nucleus water content, bulk modulus and osmotic potential on disc height loss and pressure, similar to measurements. In these events, the compression load transfer in the disc markedly altered by substantially increasing the load on the annulus when compared with the nucleus. The success of hydrogels for nucleus replacements is not only dependent on the implant material itself but also on the restoration of the environment perturbed during surgery. The substantial effects on the disc response of disruptions owing to nucleus replacements can be simulated by reduced nucleus water content, elastic modulus and osmotic potential. PMID:22337630

  7. The Ionization Source in the Nucleus of M84

    NASA Technical Reports Server (NTRS)

    Bower, G. A.; Green, R. F.; Quillen, A. C.; Danks, A.; Malumuth, E. M.; Gull, T.; Woodgate, B.; Hutchings, J.; Joseph, C.; Kaiser, M. E.

    2000-01-01

    We have obtained new Hubble Space Telescope (HST) observations of M84, a nearby massive elliptical galaxy whose nucleus contains a approximately 1.5 X 10(exp 9) solar mass dark compact object, which presumably is a supermassive black hole. Our Space Telescope Imaging Spectrograph (STIS) spectrum provides the first clear detection of emission lines in the blue (e.g., [0 II] lambda 3727, HBeta and [0 III] lambda lambda4959,5007), which arise from a compact region approximately 0".28 across centered on the nucleus. Our Near Infrared Camera and MultiObject Spectrometer (NICMOS) images exhibit the best view through the prominent dust lanes evident at optical wavelengths and provide a more accurate correction for the internal extinction. The relative fluxes of the emission lines we have detected in the blue together with those detected in the wavelength range 6295 - 6867 A by Bower et al. indicate that the gas at the nucleus is photoionized by a nonstellar process, instead of hot stars. Stellar absorption features from cool stars at the nucleus are very weak. We update the spectral energy distribution of the nuclear point source and find that although it is roughly flat in most bands, the optical to UV continuum is very red, similar to the spectral energy distribution of BL Lac. Thus, the nuclear point source seen in high-resolution optical images is not a star cluster but is instead a nonstellar source. Assuming isotropic emission from this source, we estimate that the ratio of bolometric luminosity to Eddington luminosity is about 5 x 10(exp -7). However, this could be underestimated if this source is a misaligned BL Lac object, which is a possibility suggested by the spectral energy distribution and the evidence of optical variability we describe.

  8. Neutrino-nucleus interactions at the LBNF near detector

    SciTech Connect

    Mosel, Ulrich

    2015-10-15

    The reaction mechanisms for neutrino interactions with an {sup 40}Ar nucleus with the LBNF flux are calculated with the Giessen-Boltzmann-Uehling-Uhlenbeck (GiBUU) transport-theoretical implementation of these interactions. Quasielastic scattering, many-body effects, pion production and absorption and Deep Inelastic Scattering are discussed; they all play a role at the LBNF energies and are experimentally entangled with each other. Quasielastic scattering makes up for only about 1/3 of the total cross section whereas pion production channels make up about 2/3 of the total. This underlines the need for a consistent description of the neutrino-nucleus reaction that treats all channels on an equal, consistent footing. The results discussed here can also serve as useful guideposts for the Intermediate Neutrino Program.

  9. Coulomb Excitation of the N = 50 nucleus 80Zn

    NASA Astrophysics Data System (ADS)

    van de Walle, J.; Aksouh, F.; Ames, F.; Behrens, T.; Bildstein, V.; Blazhev, A.; Cederkäll, J.; Clément, E.; Cocolios, T. E.; Davinson, T.; Delahaye, P.; Eberth, J.; Ekström, A.; Fedorov, D. V.; Fedosseev, V. N.; Fraile, L. M.; Franchoo, S.; Gernhauser, R.; Georgiev, G.; Habs, D.; Heyde, K.; Huber, G.; Huyse, M.; Ibrahim, F.; Ivanov, O.; Iwanicki, J.; Jolie, J.; Kester, O.; Köster, U.; Kröll, T.; Krücken, R.; Lauer, M.; Lisetskiy, A. F.; Lutter, R.; Marsh, B. A.; Mayet, P.; Niedermaier, O.; Nilsson, T.; Pantea, M.; Perru, O.; Raabe, R.; Reiter, P.; Sawicka, M.; Scheit, H.; Schrieder, G.; Schwalm, D.; Seliverstov, M. D.; Sieber, T.; Sletten, G.; Smirnova, N.; Stanoiu, M.; Stefanescu, I.; Thomas, J.-C.; Valiente-Dobón, J. J.; van Duppen, P.; Verney, D.; Voulot, D.; Warr, N.; Weisshaar, D.; Wenander, F.; Wolf, B. H.; Zielińska, M.

    2008-05-01

    Neutron rich Zinc isotopes, including the N = 50 nucleus 80Zn, were produced and post-accelerated at the Radioactive Ion Beam (RIB) facility REX-ISOLDE (CERN). Low-energy Coulomb excitation was induced on these isotopes after post-acceleration, yielding B(E2) strengths to the first excited 2+ states. For the first time, an excited state in 80Zn was observed and the 21+ state in 78Zn was established. The measured B(E2,21+-->01+) values are compared to two sets of large scale shell model calculations. Both calculations reproduce the observed B(E2) systematics for the full Zinc isotopic chain. The results for N = 50 isotones indicate a good N = 50 shell closure and a strong Z = 28 proton core polarization. The new results serve as benchmarks to establish theoretical models, predicting the nuclear properties of the doubly magic nucleus 78Ni.

  10. Structure of Tz = 3 / 2 , 33P Nucleus

    NASA Astrophysics Data System (ADS)

    Lubna, Rebeka Sultana; Tripathi, Vandana; Tabor, Samuel; Tai, Pei-Laun; Bender, Peter

    2016-03-01

    The excited states of the nucleus 33P were populated by the 18O(18O, p-2n γ)33P fusion evaporation reaction at Elab = 25 MeV.Gammasphere was used along with the particle detector Microball to detect the γ emissions in coincidence with the emitted charged particles from the compound nucleus 36S. The auxiliary detector Microball was used to select the charged particle channel and to determine the exact position and the energy of the emitted proton. The purpose of finding the position and energy of proton was to determine a more precise angle between the recoil nucleus and the emitted γ which was later employed to get a better Doppler correction. Along with the selection of the proton channel, the γ- γ coincidence technique helped to isolate 33P from the other phosphorus isotopes and also reduced the contaminations from the dominant pure neutron channels. A number of transitions and states was identified that were not observed before. The 4 π arrangement of Gammasphere offered an excellent opportunity to measure the angular distribution of the electromagnetic emissions leading to the assignment of the spins for most of the new states. The experimental observations were compared to the shell model calculation using Work supported by the U.S. National Science Foundation under Grant No. 1401574.

  11. Analysis of Returned Comet Nucleus Samples

    NASA Astrophysics Data System (ADS)

    Chang, Sherwood

    1997-12-01

    This volume contains abstracts that have been accepted by the Program Committee for presentation at the Workshop on Analysis of Returned Comet Nucleus Samples, held in Milpitas, California, January 16-18, 1989. Conveners are Sherwood Chang (NASA Ames Research Center) and Larry Nyquist (NASA Johnson Space Center). Program Committee members are Thomas Ahrens (ex-officio; California Institute of Technology), Lou Allamandola (NASA Ames Research Center), David Blake (NASA Ames Research Center), Donald Brownlee (University of Washington, Seattle), Theodore E. Bunch (NASA Ames Research Center), Humberto Campins (Planetary Science Institute), Jeff Cuzzi (NASA Ames Research Center), Eberhard Griin (Max-Plank-Institut fiir Kemphysik), Martha Hanner (Jet Propulsion Laboratory), Alan Harris (Jet Propulsion Laboratory), John Kerrid-e (University of Califomia, Los Angeles), Yves Langevin (University of Paris), Gerhard Schwehm (ESTEC), and Paul Weissman (Jet Propulsion Laboratory). Logistics and administrative support for the workshop were provided by the Lunar and Planetary Institute Projects Office.

  12. In situ hybridization of suprachiasmatic nucleus slices.

    PubMed

    de la Iglesia, Horacio O

    2007-01-01

    The progress in the understanding of the molecular machinery of mammalian circadian clocks, in combination with the well-established role of the hypothalamic suprachiasmatic nucleus (SCN) as a master circadian clock, has provided an invaluable system for the study of the molecular basis of circadian rhythmicity. Using in situ hybridization (ISH) techniques that label specific clock-gene mRNAs within the SCN, researchers can now elucidate the core molecular oscillatory mechanisms underlying specific circadian physiological and behavioral phenotypes. In this chapter, two methods for ISH within the SCN are described. The first method is based on the fluorescent labeling of mRNA and is suitable for confocal microscopy analysis and double labeling techniques. The second method is based on the radioactive labeling of mRNA and is more sensitive and more adequate for the relative quantification of mRNA species.

  13. The nucleus of the Cygnus A galaxy

    NASA Astrophysics Data System (ADS)

    Vestergaard, M.; Barthel, P. D.

    1993-02-01

    New obtained high resolution optical images of the prototypical luminous radio galaxy Cygnus A (3C 405) indicate an inhomogeneous distribution of obscuring dust and, in combination with previous data, three types of radiation (stellar and blue featureless continuum as well as luminous line emission) in its central regions. The alleged double nucleus finds its origin in heavy obscuration coupled to excess line emission in the central regions of an otherwise normal giant elliptical galaxy. A strongly reddened nuclear component, coincident with the Cygnus A radio core, is found to emit faint but concentrated narrow line emission. All data appear consistent with identification of Cygnus A as a radio-loud quasar having its radio axis oriented at about 35 deg from the sky plane. The presumed dust torus obscuring the quasar continuum is inferred to be smaller than 800 parsec.

  14. Nature of multiple-nucleus cluster galaxies

    SciTech Connect

    Merritt, D.

    1984-05-01

    In models for the evolution of galaxy clusters which include dynamical friction with the dark binding matter, the distribution of galaxies becomes more concentrated to the cluster center with time. In a cluster like Coma, this evolution could increase by a factor of approximately 3 the probability of finding a galaxy very close to the cluster center, without decreasing the typical velocity of such a galaxy significantly below the cluster mean. Such an enhancement is roughly what is needed to explain the large number of first-ranked cluster galaxies which are observed to have extra ''nuclei''; it is also consistent with the high velocities typically measured for these ''nuclei.'' Unlike the cannibalism model, this model predicts that the majority of multiple-nucleus systems are transient phenomena, and not galaxies in the process of merging.

  15. Nucleus of Comet P/Arend-Rigaux

    SciTech Connect

    Brooke, T.Y.; Knacke, R.F.

    1986-07-01

    Photometry data at 1-20 microns taken of Comet P/Arend-Rigaux are reported. The observations were carried out to test the possibility of observing the nuclei of low activity, nearly extinct comets at visible and IR wavelengths. The data were collected in February 1985 using the NASA 3 m IR telescope on Mauna Kea. The comet was at 1.67 AU heliocentric distance at the time. Attempts were made to detect rotation of the core on the bases of variations in the J, H and K light curves. The images obtained were those of a rotating nucleus with a radius of 4.0-6.2 km surrounded by a faint coma. The comet had a geometric albedo of 0.01-0.03 and a near-IR red slope that exhibited no evidence of the presence of ice. 32 references.

  16. Analysis of Returned Comet Nucleus Samples

    NASA Technical Reports Server (NTRS)

    Chang, Sherwood (Compiler)

    1997-01-01

    This volume contains abstracts that have been accepted by the Program Committee for presentation at the Workshop on Analysis of Returned Comet Nucleus Samples, held in Milpitas, California, January 16-18, 1989. Conveners are Sherwood Chang (NASA Ames Research Center) and Larry Nyquist (NASA Johnson Space Center). Program Committee members are Thomas Ahrens (ex-officio; California Institute of Technology), Lou Allamandola (NASA Ames Research Center), David Blake (NASA Ames Research Center), Donald Brownlee (University of Washington, Seattle), Theodore E. Bunch (NASA Ames Research Center), Humberto Campins (Planetary Science Institute), Jeff Cuzzi (NASA Ames Research Center), Eberhard Griin (Max-Plank-Institut fiir Kemphysik), Martha Hanner (Jet Propulsion Laboratory), Alan Harris (Jet Propulsion Laboratory), John Kerrid-e (University of Califomia, Los Angeles), Yves Langevin (University of Paris), Gerhard Schwehm (ESTEC), and Paul Weissman (Jet Propulsion Laboratory). Logistics and administrative support for the workshop were provided by the Lunar and Planetary Institute Projects Office.

  17. Novel associated hydrogels for nucleus pulposus replacement.

    PubMed

    Thomas, Jonathan; Lowman, Anthony; Marcolongo, Michele

    2003-12-15

    Hydrogels of poly(vinyl alcohol) (PVA) and poly(vinyl pyrrolidone) (PVP) blends may provide a material suitable for replacement of the nucleus pulposus of the intervertebral disc. This research examined the stability of these hydrogels under simulated physiological conditions. Polymer dissolution and stability were characterized over 120 days immersion, chemical surface analysis over 56 days immersion, and tensile mechanical behavior over 56 days immersion. Rubber elasticity theory was used by combining mechanical results with swelling data to calculate network characteristics such as the molecular weight between physical crosslinks and density of crosslinks. Properties were examined as a function of PVA/PVP composition as well as PVA molecular weight and PVP molecular weight. Results indicated that PVA/PVP blends prepared with moderate amounts of PVP (0.5-5%) resulted in a polymer network stabilized through interchain hydrogen bonding between hydroxyl groups on PVA chains and carbonyl groups on PVP chains. Most notably, a significant decrease in percentage of polymer mass loss was seen for blends prepared with 143K molecular weight PVA. Surface chemical analysis revealed that PVP unincorporated in the network structure suffered significant dissolution out of the polymer network and into solution. The molecular weight of PVA and PVP were shown to have a significant influence on the blends' network properties. Gels prepared with lower molecular weight PVA resulted in a more stable blend containing a higher density of crosslinks. However, blends prepared with a higher molecular weight PVA showed superior polymer network stability in dissolution studies. The blend that had the best combination of network stability under physiological conditions and a relatively tight, stable, and crosslinked network was prepared with 99% PVA (143K) and 1% PVP (40K). This material is proposed as an implant material for replacement of the degenerated nucleus pulposus.

  18. Nonlinear osmotic properties of the cell nucleus

    PubMed Central

    Finan, John D.; Chalut, Kevin J.; Wax, Adam; Guilak, Farshid

    2009-01-01

    Summary In the absence of active volume regulation processes, cell volume is inversely proportional to osmolarity, as predicted by the Boyle Van’t Hoff relation. In this study, we tested the hypothesis that nuclear volume has a similar relationship with extracellular osmolarity in articular chondrocytes, cells that are exposed to changes in the osmotic environment in vivo, and furthermore, we explored the mechanism of the relationships between osmolarity and nuclear size and shape. Nuclear size was quantified using two independent techniques, confocal laser scanning microscopy and angle-resolved low coherence interferometry. Nuclear volume was osmotically-sensitive but this relationship was not linear, showing a decline in the osmotic sensitivity in the hypo-osmotic range. Nuclear shape was also influenced by extracellular osmolarity, becoming smoother as the osmolarity decreased. The osmotically-induced changes in nuclear size paralleled the changes in nuclear shape, suggesting that shape and volume are interdependent. The osmotic sensitivity of shape and volume persisted after disruption of the actin cytoskeleton. Isolated nuclei contracted in response to physiologic changes in macromolecule concentration but not in response to physiologic changes in ion concentration, suggesting solute size has an important influence on the osmotic pressurization of the nucleus. This finding in turn implies that the diffusion barrier that causes osmotic effects is not a semi-permeable membrane, but rather due to size constraints that prevent large solute molecules from entering small spaces in the nucleus. As nuclear morphology has been associated previously with cell phenotype, these findings may provide new insight into the role of mechanical and osmotic signals in regulating cell physiology. PMID:19107599

  19. Separable Representation of Nucleon-Nucleus Optical Potentials as Input to (d; p) Reaction Calculations

    NASA Astrophysics Data System (ADS)

    Hlophe, Linda D.

    The three-body description of deuteron-induced nuclear reactions requires the nucleon-nucleon (NN) and effective nucleon-nucleus interactions as input. The latter are given by Optical Model Potentials (OMPs), which are complex as well as energy-dependent. While a lot of effort has been dedicated to creating separable NN potentials, the same is not true for the nucleon-nucleus OMPs. In this work, separable representations of nucleon-nucleus OMPs are presented. To construct separable representations of neutron-nucleus OMPs, a scheme due to Ernst, Shakin, and Thaler (EST) is adopted as a starting point. It is shown that, by including both incoming and outgoing scattering states in the EST scheme, separable expansions for complex neutron-nucleus potentials that partially obey reciprocity are obtained. For the application to neutron-nucleus potentials that are complex as well as energy-dependent, a further generalization is carried out leading to an energy-dependent separable expansion that exactly fulfills reciprocity. By working exclusively with half-shell transition matrices in momentum space, the implementation of these separable representation schemes is straightforward. The proton-nucleus interaction consists of a short-ranged nuclear piece as well as the long-ranged point-Coulomb potential. After separating the point-Coulomb piece via the Gell-Mann-Goldberger relation, one is left with the short-ranged potential in the Coulomb basis. An extension of the separable representation schemes for neutron-nucleus OMPs to proton-nucleus systems thus requires scattering solutions in the Coulomb basis. This complicates a momentum space implementation of the aforementioned separable expansions. However, by employing the techniques first suggested by Elster, Liu, and Thaler, the separable representation schemes generalized for proton-nucleus OMPs are implemented in a similar manner to neutron-nucleus OMPs. Taking into account the internal structure of the nucleus leads to

  20. Pedunculopontine nucleus evoked potentials from subthalamic nucleus stimulation in Parkinson's disease.

    PubMed

    Neagu, Bogdan; Tsang, Eric; Mazzella, Filomena; Hamani, Clement; Moro, Elena; Hodaie, Mojgan; Lozano, Andres M; Chen, Robert

    2013-12-01

    The effects of subthalamic nucleus (STN) stimulation on the pedunculopontine nucleus area (PPNR) evoked activities were examined in two patients with Parkinson's disease. The patients had previously undergone bilateral STN deep brain stimulation (DBS) and subsequently received unilateral DBS electrodes in the PPNR. Evoked potentials were recorded from the local field potentials (LFP) from the PPNR with STN stimulation at different frequencies and bipolar contacts. Ipsilateral and contralateral short latency (<2ms) PPNR responses were evoked from left but not from right STN stimulation. In both patients, STN stimulation evoked contralateral PPNR responses at medium latencies between 41 and 45ms. Cortical evoked potentials to single pulse STN stimulation were observed at latencies between 18 and 27ms. These results demonstrate a functional connection between the STN and the PPNR. It likely involves direct projections between the STN and PPNR or polysynaptic pathways with thalamic or cortical relays.

  1. Fluctuation analysis of relativistic nucleus-nucleus collisions in emulsion chambers

    NASA Technical Reports Server (NTRS)

    Mcguire, Stephen C.

    1988-01-01

    An analytical technique was developed for identifying enhanced fluctuations in the angular distributions of secondary particles produced from relativistic nucleus-nucleus collisions. The method is applied under the assumption that the masses of the produced particles are small compared to their linear momenta. The importance of particles rests in the fact that enhanced fluctuations in the rapidity distributions is considered to be an experimental signal for the creation of the quark-gluon-plasma (QGP), a state of nuclear matter predicted from the quantum chromodynamics theory (QCD). In the approach, Monte Carlo simulations are employed that make use of a portable random member generator that allow the calculations to be performed on a desk-top computer. The method is illustrated with data taken from high altitude emulsion exposures and is immediately applicable to similar data from accelerator-based emulsion exposures.

  2. Nucleus and nucleus-cytoskeleton connections in 3D cell migration.

    PubMed

    Liu, Lingling; Luo, Qing; Sun, Jinghui; Song, Guanbin

    2016-10-15

    Cell migration plays an important role in many physiological and pathological settings, ranging from embryonic development to cancer metastasis. Currently, accumulating data suggest that cells migrating in three-dimensional (3D) environments show well-defined differences compared to their well-established two-dimensional (2D) counterparts. During 3D migration, the cell body and nucleus must deform to allow cellular passage through the available spaces, and the deformability of the relatively rigid nucleus may constitute a limiting step. Here, we highlight the key evidence regarding the role of the nuclear mechanics in 3D migration, including the molecular components that govern the stiffness of the nucleus and review how the nuclear dynamics are connected to and controlled by cytoskeleton-based migration machinery. Intriguingly, nuclear movement must be coordinated with the cytoskeletal dynamics at the leading and trailing edges, which in turn impact the cytoplasmic dynamics that affect the migration efficiency. Thus, we suggest that alterations in the nuclear structure may facilitate cellular reorganizations that are necessary for efficient migration.

  3. Mission CaMKIIγ: shuttle calmodulin from membrane to nucleus.

    PubMed

    Malik, Zulfiqar A; Stein, Ivar S; Navedo, Manuel F; Hell, Johannes W

    2014-10-09

    Neuronal plasticity depends on plasma membrane Ca(2+) influx, resulting in activity-dependent gene transcription. Calmodulin (CaM) activated by Ca(2+) initiates the nuclear events, but how CaM makes its way to the nucleus has remained elusive. Ma et al. now show that CaMKIIγ transports CaM from cell surface Ca(2+) channels to the nucleus.

  4. Cytotoxicity of nucleus-targeting fluorescent gold nanoclusters.

    PubMed

    Zhao, Jing-Ya; Cui, Ran; Zhang, Zhi-Ling; Zhang, Mingxi; Xie, Zhi-Xiong; Pang, Dai-Wen

    2014-11-07

    Gold nanoclusters (AuNCs) with ultra small sizes and unique fluorescence properties have shown promising potential for imaging the nuclei of living cells. However, little is known regarding the potential cytotoxicity of AuNCs after they enter the cell nucleus. The aim of this study is to investigate whether and how nucleus-targeting AuNCs affect the normal functioning of cells. Highly stable, water-soluble and bright fluorescent Au25NCs (the core of each nanocluster is composed of 25 gold atoms) were synthesized. Specific targeting of Au25NCs to the cell nucleus was achieved by conjugating the TAT peptide to the Au25NCs. Cell viability, cell morphology, cell apoptosis/necrosis, reactive oxygen species (ROS) level and mitochondrial membrane potential examinations were performed on different cell lines exposed to the nucleus-targeting Au25NCs. We found that the nucleus-targeting Au25NCs caused cell apoptosis in a dose-dependent manner. A possible mechanism for the cytotoxicity of the nucleus-targeting Au25NCs was proposed as follows: the nucleus-targeting Au25NCs induce the production of ROS, resulting in the oxidative degradation of mitochondrial components, in turn leading to apoptosis via a mitochondrial damage pathway. This work facilitates a better understanding of the toxicity of AuNCs, especially nucleus-targeting AuNCs.

  5. Glutamatergic projection from the nucleus incertus to the septohippocampal system.

    PubMed

    Cervera-Ferri, Ana; Rahmani, Yasamin; Martínez-Bellver, Sergio; Teruel-Martí, Vicent; Martínez-Ricós, Joana

    2012-05-31

    Recent findings support a relevant role of the nucleus incertus in the control of the hippocampal activity through the modulation of theta rhythm. Previous studies from our group have shown that this nucleus is a critical relay between reticularis pontis oralis and the medial septum/diagonal band, regarded as the main activator and the pacemaker of the hippocampal oscillations, respectively. Besides, the nucleus incertus is highly linked to activated states related to the arousal response. The neurotransmission of the nucleus incertus, however, remains uncertain. Only GABA and the neuromodulator relaxin 3 are usually considered to be involved in its contribution to the septohippocampal system. In this work, we have analyzed the existence of an excitatory projection from the nucleus incertus to the medial septum. We have found a group of glutamatergic neurons in the nucleus incertus projecting to the medial septum. Moreover, we were able to describe a segregated distribution of calbindin and calretinin neurons. While calretinin expression was restricted to the nucleus incertus pars compacta, calbindin positive neurons where observed both in the pars dissipata and the pars compacta of the nucleus. The present work provides innovative data supporting an excitatory component in the pontoseptal pathway.

  6. Afferent projections to the deep mesencephalic nucleus in the rat

    SciTech Connect

    Veazey, R.B.; Severin, C.M.

    1982-01-10

    Afferent projections to the deep mesencephalic nucleus (DMN) of the rat were demonstrated with axonal transport techniques. Potential sources for projections to the DMN were first identified by injecting the nucleus with HRP and examining the cervical spinal cord, brain stem, and cortex for retrogradely labeled neurons. Areas consistently labeled were then injected with a tritiated radioisotope, the tissue processed for autoradiography, and the DMN examined for anterograde labeling. Afferent projections to the medial and/or lateral parts of the DMN were found to originate from a number of spinal, bulbar, and cortical centers. Rostral brain centers projecting to both medial and lateral parts of the DMN include the ipsilateral motor and somatosensory cortex, the entopeduncular nucleus, and zona incerta. at the level of the midbrain, the ipsilateral substantia nigra and contralateral DMN likewise project to the DMN. Furthermore, the ipsilateral superior colliculus projects to the DMN, involving mainly the lateral part of the nucleus. Afferents from caudal centers include bilateral projections from the sensory nucleus of the trigeminal complex and the nucleus medulla oblongata centralis, as well as from the contralateral dentate nucleus. The projections from the trigeminal complex and nucleus medullae oblongatae centralis terminate in the intermediate and medial parts of the DMN, whereas projections from the contralateral dentate nucleus terminate mainly in its lateral part. In general, the afferent connections of the DMN arise from diverse areas of the brain. Although most of these projections distribute throughout the entire extent of the DMN, some of them project mainly to either medial or lateral parts of the nucleus, thus suggesting that the organization of the DMN is comparable, at least in part, to that of the reticular formation of the pons and medulla, a region in which hodological differences between medial and lateral subdivisions are known to exist.

  7. Nucleon emission via electromagnetic excitation in relativistic nucleus-nucleus collisions: Re-analysis of the Weizsacker-Williams method

    NASA Technical Reports Server (NTRS)

    Norbury, John W.

    1989-01-01

    Previous analyses of the comparison of Weizsacker-Williams (WW) theory to experiment for nucleon emission via electromagnetic (EM) excitations in nucleus-nucleus collisions were not definitive because of different assumptions concerning the value of the minimum impact parameter. This situation is corrected by providing criteria that allows definitive statements to be made concerning agreement or disagreement between WW theory and experiment.

  8. Glycine immunoreactivity of multipolar neurons in the ventral cochlear nucleus which project to the dorsal cochlear nucleus.

    PubMed

    Doucet, J R; Ross, A T; Gillespie, M B; Ryugo, D K

    1999-06-14

    Certain distinct populations of neurons in the dorsal cochlear nucleus are inhibited by a neural source that is responsive to a wide range of acoustic frequencies. In this study, we examined the glycine immunoreactivity of two types of ventral cochlear nucleus neurons (planar and radiate) in the rat which project to the dorsal cochlear nucleus (DCN) and thus, might be responsible for this inhibition. Previously, we proposed that planar neurons provided a tonotopic and narrowly tuned input to the DCN, whereas radiate neurons provided a broadly tuned input and thus, were strong candidates as the source of broadband inhibition (Doucet and Ryugo [1997] J. Comp. Neurol. 385:245-264). We tested this idea by combining retrograde labeling and glycine immunohistochemical protocols. Planar and radiate neurons were first retrogradely labeled by injecting biotinylated dextran amine into a restricted region of the dorsal cochlear nucleus. The labeled cells were visualized using streptavidin conjugated to indocarbocyanine (Cy3), a fluorescent marker. Sections that contained planar or radiate neurons were then processed for glycine immunocytochemistry using diaminobenzidine as the chromogen. Immunostaining of planar neurons was light, comparable to that of excitatory neurons (pyramidal neurons in the DCN), whereas immunostaining of radiate neurons was dark, comparable to that of glycinergic neurons (cartwheel cells in the dorsal cochlear nucleus and principal cells in the medial nucleus of the trapezoid body). These results are consistent with the hypothesis that radiate neurons in the ventral cochlear nucleus subserve the wideband inhibition observed in the dorsal cochlear nucleus.

  9. α and 3He production in the 7Be+28Si reaction at near-barrier energies: Direct versus compound-nucleus mechanisms

    NASA Astrophysics Data System (ADS)

    Sgouros, O.; Pakou, A.; Pierroutsakou, D.; Mazzocco, M.; Acosta, L.; Aslanoglou, X.; Betsou, Ch.; Boiano, A.; Boiano, C.; Carbone, D.; Cavallaro, M.; Grebosz, J.; Keeley, N.; La Commara, M.; Manea, C.; Marquinez-Duran, G.; Martel, I.; Nicolis, N. G.; Parascandolo, C.; Rusek, K.; Sánchez-Benítez, A. M.; Signorini, C.; Soramel, F.; Soukeras, V.; Stefanini, C.; Stiliaris, E.; Strano, E.; Strojek, I.; Torresi, D.

    2016-10-01

    The production of α and 3He particles, the cluster constituents of 7Be, in the 7Be+28Si reaction was studied at three near-barrier energies, namely 13, 20, and 22 MeV. Angular distribution measurements were performed at each energy, and the data were analyzed in both statistical model and Distorted-Wave Born Approximation (DWBA) frameworks in order to disentangle the degree of competition between direct and compound channels. The energy evolution of the ratio of direct to total reaction cross section was mapped in comparison with similar data for 6Li and 7Li projectiles on a 28Si target. The results indicate larger transfer contributions for collisions involving the mirror nuclei 7Be and 7Li than in the 6Li case. Fusion cross sections were deduced, taking into account the α -particle cross sections due to compound-nucleus formation and particle multiplicities deduced from our statistical model framework. It was found that fusion is compatible with systematics and single-barrier penetration cross sections to within an uncertainty band of 10% to 20%. Indications of fusion hindrance for 7Li and 7Be compared to 6Li, starting from the barrier and below it, are given. This hindrance is attributed to the existence of large transfer channels. Furthermore, the experimental results, analyzed in the DWBA framework, suggest 3He and 4He transfer as the dominant direct reaction mechanism.

  10. Control of nucleus accumbens activity with neurofeedback.

    PubMed

    Greer, Stephanie M; Trujillo, Andrew J; Glover, Gary H; Knutson, Brian

    2014-08-01

    The nucleus accumbens (NAcc) plays critical roles in healthy motivation and learning, as well as in psychiatric disorders (including schizophrenia and attention deficit hyperactivity disorder). Thus, techniques that confer control of NAcc activity might inspire new therapeutic interventions. By providing second-to-second temporal resolution of activity in small subcortical regions, functional magnetic resonance imaging (fMRI) can resolve online changes in NAcc activity, which can then be presented as "neurofeedback." In an fMRI-based neurofeedback experiment designed to elicit NAcc activity, we found that subjects could increase their own NAcc activity, and that display of neurofeedback significantly enhanced their ability to do so. Subjects were not as capable of decreasing their NAcc activity, however, and enhanced control did not persist after subsequent removal of neurofeedback. Further analyses suggested that individuals who recruited positive aroused affect were better able to increase NAcc activity in response to neurofeedback, and that NAcc neurofeedback also elicited functionally correlated activity in the medial prefrontal cortex. Together, these findings suggest that humans can modulate their own NAcc activity and that fMRI-based neurofeedback may augment their efforts. The observed association between positive arousal and effective NAcc control further supports an anticipatory affect account of NAcc function.

  11. Functional network inference of the suprachiasmatic nucleus

    PubMed Central

    Abel, John H.; Meeker, Kirsten; Granados-Fuentes, Daniel; St. John, Peter C.; Wang, Thomas J.; Bales, Benjamin B.; Doyle, Francis J.; Herzog, Erik D.; Petzold, Linda R.

    2016-01-01

    In the mammalian suprachiasmatic nucleus (SCN), noisy cellular oscillators communicate within a neuronal network to generate precise system-wide circadian rhythms. Although the intracellular genetic oscillator and intercellular biochemical coupling mechanisms have been examined previously, the network topology driving synchronization of the SCN has not been elucidated. This network has been particularly challenging to probe, due to its oscillatory components and slow coupling timescale. In this work, we investigated the SCN network at a single-cell resolution through a chemically induced desynchronization. We then inferred functional connections in the SCN by applying the maximal information coefficient statistic to bioluminescence reporter data from individual neurons while they resynchronized their circadian cycling. Our results demonstrate that the functional network of circadian cells associated with resynchronization has small-world characteristics, with a node degree distribution that is exponential. We show that hubs of this small-world network are preferentially located in the central SCN, with sparsely connected shells surrounding these cores. Finally, we used two computational models of circadian neurons to validate our predictions of network structure. PMID:27044085

  12. Functional network inference of the suprachiasmatic nucleus

    SciTech Connect

    Abel, John H.; Meeker, Kirsten; Granados-Fuentes, Daniel; St. John, Peter C.; Wang, Thomas J.; Bales, Benjamin B.; Doyle, Francis J.; Herzog, Erik D.; Petzold, Linda R.

    2016-04-04

    In the mammalian suprachiasmatic nucleus (SCN), noisy cellular oscillators communicate within a neuronal network to generate precise system-wide circadian rhythms. Although the intracellular genetic oscillator and intercellular biochemical coupling mechanisms have been examined previously, the network topology driving synchronization of the SCN has not been elucidated. This network has been particularly challenging to probe, due to its oscillatory components and slow coupling timescale. In this work, we investigated the SCN network at a single-cell resolution through a chemically induced desynchronization. We then inferred functional connections in the SCN by applying the maximal information coefficient statistic to bioluminescence reporter data from individual neurons while they resynchronized their circadian cycling. Our results demonstrate that the functional network of circadian cells associated with resynchronization has small-world characteristics, with a node degree distribution that is exponential. We show that hubs of this small-world network are preferentially located in the central SCN, with sparsely connected shells surrounding these cores. Finally, we used two computational models of circadian neurons to validate our predictions of network structure.

  13. Development of the human dentate nucleus.

    PubMed

    Mihajlovic, P; Zecevic, N

    1986-01-01

    The developing human dentate nucleus (DN) was studied in a series of specimens of various pre- and postnatal ages ranging from 8 gestational weeks (gw) to 10 years, in Golgi-impregnated and Nissl-stained material. The DN emerges from the cerebellar white matter at around 16 gestational weeks (gw) as a thick band of cells (600-700 micron in width) that gradually attenuates to a final width of 150-250 micron as it undergoes extensive infolding beginning around 24 gw. The highly convoluted configuration of the adult DN is recognizable by 35 gw. Around 16 gw, two basic classes of DN neurons can be identified. Differentiation of these neurons is especially intensive during the mid-gestational period (20-25 gw). At this time the size of cell bodies increases, dendrites branch profusely and acquire spines. A second, slower phase of maturation consisting of addition of secondary and tertiary branches, continues into the postnatal period. At all prenatal ages examined, dentate neurons are morphologically more mature than the Purkinje cells in the overlying cortex. DN neurons of premature infants did not show cytomorphological differences when compared with babies born at term.

  14. Calretinin Neurons in the Rat Suprachiasmatic Nucleus.

    PubMed

    Moore, Robert Y

    2016-08-01

    The hypothalamic suprachiasmatic nucleus (SCN), a circadian pacemaker, is present in all mammalian brains. It has a complex organization of peptide-containing neurons that is similar among species, but calcium-binding proteins are expressed variably. Neurons containing calretinin have been described in the SCN in a number of species but not with association to circadian function. The objective of the present study is to characterize a calretinin neuron (CAR) group in the rat anterior hypothalamus anatomically and functionally with a detailed description of its location and a quantitative analysis of neuronal calretinin immunoreactivity at 3 times of day, 0600, 1400, and 1900 h, from animals in either light-dark or constant dark conditions. CAR neurons occupy a region in the dorsal and lateral SCN with a circadian rhythm in CAR immunoreactivity with a peak at 0600 h and a rhythm in cytoplasmic CAR distribution with a peak at 1400 h. CAR neurons should be viewed as an anatomical and functional component of the rat SCN that expands the definition from observations with cell stains. CAR neurons are likely to modulate temporal regulation of calcium in synaptic transmission.

  15. Comparing Realistic Subthalamic Nucleus Neuron Models

    NASA Astrophysics Data System (ADS)

    Njap, Felix; Claussen, Jens C.; Moser, Andreas; Hofmann, Ulrich G.

    2011-06-01

    The mechanism of action of clinically effective electrical high frequency stimulation is still under debate. However, recent evidence points at the specific activation of GABA-ergic ion channels. Using a computational approach, we analyze temporal properties of the spike trains emitted by biologically realistic neurons of the subthalamic nucleus (STN) as a function of GABA-ergic synaptic input conductances. Our contribution is based on a model proposed by Rubin and Terman and exhibits a wide variety of different firing patterns, silent, low spiking, moderate spiking and intense spiking activity. We observed that most of the cells in our network turn to silent mode when we increase the GABAA input conductance above the threshold of 3.75 mS/cm2. On the other hand, insignificant changes in firing activity are observed when the input conductance is low or close to zero. We thus reproduce Rubin's model with vanishing synaptic conductances. To quantitatively compare spike trains from the original model with the modified model at different conductance levels, we apply four different (dis)similarity measures between them. We observe that Mahalanobis distance, Victor-Purpura metric, and Interspike Interval distribution are sensitive to different firing regimes, whereas Mutual Information seems undiscriminative for these functional changes.

  16. Development of the human dorsal nucleus of the vagus.

    PubMed

    Cheng, Gang; Zhu, Hua; Zhou, Xiangtian; Qu, Jia; Ashwell, K W S; Paxinos, G

    2008-01-01

    The dorsal nucleus of the vagus nerve plays an integral part in the control of visceral function. The aim of the present study was to correlate structural and chemical changes in the developing nucleus with available data concerning functional maturation of human viscera and reflexes. The fetal development (ages 9 to 26 weeks) of the human dorsal nucleus of the vagus nerve has been examined with the aid of Nissl staining and immunocytochemistry for calbindin and tyrosine hydroxylase. By 13 weeks, the dorsal vagal nucleus emerges as a distinct structure with at least two subnuclei visible in Nissl stained preparations. By 15 weeks, three subnuclei (dorsal intermediate, centrointermediate and ventrointermediate) were clearly discernible at the open medulla level with caudal and caudointermediate subnuclei visible at the level of the area postrema. All subnuclei known to exist in the adult were visible by 21 weeks and cytoarchitectonic differentiation of the nucleus was largely completed by 25 weeks. The adult distribution pattern of calbindin and tyrosine hydroxylase immunoreactive neurons was also largely completed by 21 weeks, although morphological differentiation of labeled neurons continued until the last age examined (26 weeks). The structural development of the dorsal nucleus of the vagus nerve appears to occur in parallel with functional maturation of the cardiovascular and gastric movements, which the nucleus controls.

  17. Did Struve observe the nucleus of Halley's comet in 1835?

    NASA Astrophysics Data System (ADS)

    Wittmann, Axel D.

    During its apparition in 1835 Halley's comet reached its minimum distance from the earth (0.187 au) on 13 October in the constellation of Ursa Major. Telescopic visual observations were made, e.g., by F.W. Bessel at Königsberg and by F.G.W. Struve at Dorpat (Tartu). In particular a drawing made by Struve on 8 October of what he calls the `nucleus' and describes as a small, slightly yellowish glowing piece of coal of elongated shape bears such a striking resemblance to the images of Halley's nucleus obtained in 1986 by the Giotto spacecraft that it merits further examination: Could Struve, who had been using a 24.4 cm refractor at 254-fold magnification, possibly have observed the real nucleus? Closer examination shows that neither Struve's maximum possible resolution (0.13 arc seconds or 23 km at the comet), nor his measured size of the nucleus (160 x 400 km), nor his verbal description of the nucleus (as a bright object) support this idea: It rather seems that the term `nucleus' was used at the time for the brightest, innermost part of the coma. It is concluded that, nevertheless, Struve quite correctly envisaged the structure of the innermost coma, and to a considerable degree of accuracy anticipated the correct shape and structure of the nucleus (elongated, 1:2) and its localized sources of outstreaming gas.

  18. Angiotensin receptor binding and pressor effects in cat subretrofacial nucleus

    SciTech Connect

    Allen, A.M.; Dampney, R.A.L.; Mendelsohn, F.A.O. Univ. of Sydney )

    1988-11-01

    Central administration of angiotensin II (ANG II) increases arterial blood pressure via increased sympathetic activity. The authors have examined the possibility that one site of action of ANG II is the subretrofacial (SRF) nucleus in the rostral ventrolateral medulla, since this nucleus is known to play a critical role in the tonic and phasic control of arterial pressure. In vitro autoradiography, employing {sup 125}I-labeled (Sar{sup 1}, Ile{sup 8})ANG II as radioligand, was used to localize binding sites for ANG-II in the cat ventrolateral medulla. A high density of ANG II-receptor binding sites was found confined to the SRF nucleus. In a second group of experiments in anesthetized cats, microinjections of ANG II, in doses ranging from 10 to 50 pmol, were made into histologically identified sites within and outside the SRF nucleus. Microinjections into the nucleus resulted in a dose-dependent increase in arterial pressure, which was abolished by systemic administration of the ganglion-blocking drug hexamethonium bromide. In contrast, microinjections just outside the SRF nucleus had no effect on arterial pressure. It is concluded that activation of ANG II-receptor binding sites within the SRF nucleus leads to an increase in arterial pressure via increased sympathetic efferent activity.

  19. Antinucleus-Nucleus Cross Sections Implemented in Geant4

    SciTech Connect

    Uzhinsky, V.; Apostolakis, J.; Galoyan, A.; Folger, G.; Grichine, V.M.; Ivanchenko, V.N.; Wright, D.H.; /SLAC

    2012-04-26

    Cross sections of antinucleus ({bar p}, {bar d}, {bar t}, {sup 3}{ovr He}, {sup 4}{ovr He}) interactions with nuclei in the energy range 100 MeV/c to 1000 GeV/c per antinucleon are calculated in the Glauber approximation which provides good description of all known {bar p}Across sections. The results were obtained using a new parameterization of the total and elastic {bar p}p cross sections. Simple parameterizations of the antinucleus-nucleus cross sections are proposed for use in estimating the efficiency of antinucleus detection and tracking in cosmic rays and accelerator experiments. These parameterizations are implemented in the Geant4 toolkit.

  20. Degeneration and energy shortage in the suprachiasmatic nucleus underlies the circadian rhythm disturbance in ApoE−/− mice: implications for Alzheimer’s disease

    PubMed Central

    Zhou, Lan; Gao, Qian; Nie, Meng; Gu, Jing-Li; Hao, Wei; Wang, Lin; Cao, Ji-Min

    2016-01-01

    Alzheimer’s disease (AD) patients suffer sleep disorders and circadian rhythm disturbances (CRDs). The underlying mechanisms are incompletely understood, and treatments are lacking. In this study, we characterized the locomotor activity, clock gene expression, morphological degeneration and energy metabolism of suprachiasmatic nucleus (SCN), together with retinal light sensing, in ApoE−/− mice, a model for AD. Compared with the control C57BL/6J mice, ApoE−/− mice exhibited disordered circadian locomotor activity under dim light and constant darkness, with impaired re-entrainment to phase change schedules. Decreased retinal melanopsin expression, together with amyloidosis and tau deposition, was evident in ApoE−/− mice. Mitochondrial and synaptic deterioration, altered SIRT1-mediated energy metabolism and clock gene expression were also observed in ApoE−/− SCN. Supplementation with fat or ketone bodies but not glucose, or intraperitoneal administration of nicotinamide, restored the locomotor rhythmicity and circadian expression of SIRT1 and clock genes, as well as reducing neurodegeneration. Taken together, ApoE deficiency induced degeneration and a significant disturbance in the SCN rhythmicity. Decline of retinal light sensing and SCN structural and metabolic deteriorations represented the major pathologies accounting for the CRDs in ApoE−/− mice. Our curative experiments may help develop future therapies to treat the CRDs and sleep disorders in AD patients. PMID:27824104

  1. The Suprachiasmatic Nucleus Modulates the Sensitivity of Arcuate Nucleus to Hypoglycemia in the Male Rat.

    PubMed

    Herrera-Moro Chao, D; León-Mercado, L; Foppen, E; Guzmán-Ruiz, M; Basualdo, M C; Escobar, C; Buijs, R M

    2016-09-01

    The suprachiasmatic nucleus (SCN) and arcuate nucleus (ARC) have reciprocal connections; catabolic metabolic information activates the ARC and inhibits SCN neuronal activity. Little is known about the influence of the SCN on the ARC. Here, we investigated whether the SCN modulated the sensitivity of the ARC to catabolic metabolic conditions. ARC neuronal activity, as determined by c-Fos immunoreactivity, was increased after a hypoglycemic stimulus by 2-deoxyglucose (2DG). The highest ARC neuronal activity after 2DG was found at the end of the light period (zeitgeber 11, ZT11) with a lower activity in the beginning of the light period (zeitgeber 2, ZT2), suggesting the involvement of the SCN. The higher activation of ARC neurons after 2DG at ZT11 was associated with higher 2DG induced blood glucose levels as compared with ZT2. Unilateral SCN-lesioned animals, gave a mainly ipsilateral activation of ARC neurons at the lesioned side, suggesting an inhibitory role of the SCN on ARC neurons. The 2DG-induced counterregulatory glucose response correlated with increased ARC neuronal activity and was significantly higher in unilateral SCN-lesioned animals. Finally, the ARC as site where 2DG may, at least partly, induce a counterregulatory response was confirmed by local microdialysis of 2DG. 2DG administration in the ARC produced a higher increase in circulating glucose compared with 2DG administration in surrounding areas such as the ventromedial nucleus of the hypothalamus (VMH). We conclude that the SCN uses neuronal pathways to the ARC to gate sensory metabolic information to the brain, regulating ARC glucose sensitivity and counterregulatory responses to hypoglycemic conditions.

  2. Determination of electron-nucleus collisions geometry with forward neutrons

    DOE PAGES

    Zheng, L.; Aschenauer, E.; Lee, J. H.

    2014-12-29

    There are a large number of physics programs one can explore in electron-nucleus collisions at a future electron-ion collider. Collision geometry is very important in these studies, while the measurement for an event-by-event geometric control is rarely discussed in the prior deep-inelastic scattering experiments off a nucleus. This paper seeks to provide some detailed studies on the potential of tagging collision geometries through forward neutron multiplicity measurements with a zero degree calorimeter. As a result, this type of geometry handle, if achieved, can be extremely beneficial in constraining nuclear effects for the electron-nucleus program at an electron-ion collider.

  3. Nucleus accumbens invulnerability to methamphetamine neurotoxicity.

    PubMed

    Kuhn, Donald M; Angoa-Pérez, Mariana; Thomas, David M

    2011-01-01

    Methamphetamine (Meth) is a neurotoxic drug of abuse that damages neurons and nerve endings throughout the central nervous system. Emerging studies of human Meth addicts using both postmortem analyses of brain tissue and noninvasive imaging studies of intact brains have confirmed that Meth causes persistent structural abnormalities. Animal and human studies have also defined a number of significant functional problems and comorbid psychiatric disorders associated with long-term Meth abuse. This review summarizes the salient features of Meth-induced neurotoxicity with a focus on the dopamine (DA) neuronal system. DA nerve endings in the caudate-putamen (CPu) are damaged by Meth in a highly delimited manner. Even within the CPu, damage is remarkably heterogeneous, with ventral and lateral aspects showing the greatest deficits. The nucleus accumbens (NAc) is largely spared the damage that accompanies binge Meth intoxication, but relatively subtle changes in the disposition of DA in its nerve endings can lead to dramatic increases in Meth-induced toxicity in the CPu and overcome the normal resistance of the NAc to damage. In contrast to the CPu, where DA neuronal deficiencies are persistent, alterations in the NAc show a partial recovery. Animal models have been indispensable in studies of the causes and consequences of Meth neurotoxicity and in the development of new therapies. This research has shown that increases in cytoplasmic DA dramatically broaden the neurotoxic profile of Meth to include brain structures not normally targeted for damage. The resistance of the NAc to Meth-induced neurotoxicity and its ability to recover reveal a fundamentally different neuroplasticity by comparison to the CPu. Recruitment of the NAc as a target of Meth neurotoxicity by alterations in DA homeostasis is significant in light of the numerous important roles played by this brain structure.

  4. Beam-energy dependence and updated test of the Trojan-horse nucleus invariance via a measurement of the 2H(d ,p )3H reaction at low energies

    NASA Astrophysics Data System (ADS)

    Li, Chengbo; Wen, Qungang; Tumino, A.; Fu, Yuanyong; Zhou, Jing; Zhou, Shuhua; Meng, Qiuying; Spitaleri, C.; Pizzone, R. G.; Lamia, L.

    2017-03-01

    The 2H(d ,p )3H bare nucleus astrophysical S (E ) factor has been measured indirectly at energies from about 500 keV down to several keV by means of the Trojan-horse method applied to the 2H(6Li,p t )4He quasifree reaction induced at 11 MeV. The obtained results are compared with direct data as well as with previous indirect investigation of the same binary reactions. It shows that the precision of S (E ) data in the low-energy range extracted via the same Trojan-horse nuclei [6Li=(d ⊕α )] becomes better when the incident energy of the virtual binary process decreases from high value down to the lower Gamow energy range, which near the zero-quasi-free-energy point. The very good agreement between data extracted from different Trojan-horse nuclei [6Li=(d ⊕α ) vs 3He=(d ⊕p )] gives a strong updated test for the independence of the binary indirect cross section on the chosen Trojan-horse nucleus at low energies.

  5. Pion production at 180/sup 0/ in nucleus-nucleus collisions

    SciTech Connect

    Chessin, S.A.

    1983-05-01

    A survey experiment of pion production at 180/sup 0/ in nucleus-nucleus collisions is presented. Beams of 1.05 GeV/A and 2.1 GeV/A protons, alphas, and carbon were used, as well as proton beams of 0.80 GeV, 3.5 GeV, and 4.89 GeV, and argon beams of 1.05 GeV/A and 1.83 GeV/A. This is the first such experiment to use the heavier beams. Targets used ranged from carbon to lead. An in-depth review of the literature, both experimental and theoretical, is also presented. The systematics of the data are discussed, and comparisons are made both with prior experiments and with the predictions of the models reviewed. The cross sections appear consistent with a simple single nucleon-nucleon collision picture, without the need for collective or other exotic effects. Suggestions for future work are made.

  6. Interaction between hypothalamic dorsomedial nucleus and the suprachiasmatic nucleus determines intensity of food anticipatory behavior

    PubMed Central

    Acosta-Galvan, Guadalupe; Yi, Chun-Xia; van der Vliet, Jan; Jhamandas, Jack H.; Panula, Pertti; Angeles-Castellanos, Manuel; del Carmen Basualdo, María; Escobar, Carolina; Buijs, Ruud M.

    2011-01-01

    Food anticipatory behavior (FAA) is induced by limiting access to food for a few hours daily. Animals anticipate this scheduled meal event even without the suprachiasmatic nucleus (SCN), the biological clock. Consequently, a food-entrained oscillator has been proposed to be responsible for meal time estimation. Recent studies suggested the dorsomedial hypothalamus (DMH) as the site for this food-entrained oscillator, which has led to considerable controversy in the literature. Herein we demonstrate by means of c-Fos immunohistochemistry that the neuronal activity of the suprachiasmatic nucleus (SCN), which signals the rest phase in nocturnal animals, is reduced when animals anticipate the scheduled food and, simultaneously, neuronal activity within the DMH increases. Using retrograde tracing and confocal analysis, we show that inhibition of SCN neuronal activity is the consequence of activation of GABA-containing neurons in the DMH that project to the SCN. Next, we show that DMH lesions result in a loss or diminution of FAA, simultaneous with increased activity in the SCN. A subsequent lesion of the SCN restored FAA. We conclude that in intact animals, FAA may only occur when the DMH inhibits the activity of the SCN, thus permitting locomotor activity. As a result, FAA originates from a neuronal network comprising an interaction between the DMH and SCN. Moreover, this study shows that the DMH–SCN interaction may serve as an intrahypothalamic system to gate activity instead of rest overriding circadian predetermined temporal patterns. PMID:21402951

  7. Suprachiasmatic Nucleus Interaction with the Arcuate Nucleus; Essential for Organizing Physiological Rhythms

    PubMed Central

    Guzmán-Ruiz, Mara

    2017-01-01

    Abstract The suprachiasmatic nucleus (SCN) is generally considered the master clock, independently driving all circadian rhythms. We recently demonstrated the SCN receives metabolic and cardiovascular feedback adeptly altering its neuronal activity. In the present study, we show that microcuts effectively removing SCN-arcuate nucleus (ARC) interconnectivity in Wistar rats result in a loss of rhythmicity in locomotor activity, corticosterone levels, and body temperature in constant dark (DD) conditions. Elimination of these reciprocal connections did not affect SCN clock gene rhythmicity but did cause the ARC to desynchronize. Moreover, unilateral SCN lesions with contralateral retrochiasmatic microcuts resulted in identical arrhythmicity, proving that for the expression of physiological rhythms this reciprocal SCN-ARC interaction is essential. The unaltered SCN c-Fos expression following glucose administration in disconnected animals as compared to a significant decrease in controls demonstrates the importance of the ARC as metabolic modulator of SCN neuronal activity. Together, these results indicate that the SCN is more than an autonomous clock, and forms an essential component of a larger network controlling homeostasis. The present novel findings illustrate how an imbalance between SCN and ARC communication through circadian disruption could be involved in the etiology of metabolic disorders. PMID:28374011

  8. Reduction of 3-methoxytyramine concentrations in the caudate nucleus of rats after exposure to high-energy iron particles: Evidence for deficits in dopaminergic neurons

    SciTech Connect

    Hunt, W.A.; Dalton, T.K.; Joseph, J.A.; Rabin, B.M.

    1990-01-01

    The prospect of long-term space travel raises a number of questions about the safety of astronauts asked to venture on prolonged journeys. The problems of microgravity are well known, but the hazards of exposure to radation are less understood. Most space travel has involved a few days to many months in low-altitude, equatorial orbits, where the dangers of radiation are lessened by the magnetic field surrounding the earth. Travel to polar or geostationary orbits or travel to the moon or the planets has a far greater radiation hazard. Almost nothing is known about possible risks to behavior and brain function after radiation exposure, such as found after the emission of solar flares or from long-term exposure from galactic cosmic radiation. Exposure to low doses of high-energy iron particles can alter motor behavior. The ability of rats to hang from a wire has been reported to be significantly degraded after exposure to doses as low as 0.5 Gy. In addition, deficits in the ability of acetylcholine to regulate dopamine release in the caudate nucleus (an area in the brain important for motor function) have been found. These results provide further evidence that exposure to heavy particles can degrade motor behavior through an action on dopaminergic mechanisms and that this can occur after doses much lower than those needed for low-LET radiation.

  9. Impact of low-energy nuclear excitations on neutrino-nucleus scattering at MiniBooNE and T2K kinematics

    NASA Astrophysics Data System (ADS)

    Pandey, V.; Jachowicz, N.; Martini, M.; González-Jiménez, R.; Ryckebusch, J.; Van Cuyck, T.; Van Dessel, N.

    2016-11-01

    Background: Meticulous modeling of neutrino-nucleus interactions is essential to achieve the unprecedented precision goals of present and future accelerator-based neutrino-oscillation experiments. Purpose: Confront our calculations of charged-current quasielastic cross sections with the measurements of MiniBooNE and T2K, and to quantitatively investigate the role of nuclear-structure effects, in particular, low-energy nuclear excitations in forward muon scattering. Method: The model takes the mean-field approach as the starting point, and solves Hartree-Fock (HF) equations using a Skyrme (SkE2) nucleon-nucleon interaction. Long-range nuclear correlations are taken into account by means of the continuum random-phase approximation (CRPA) framework. Results: We present our calculations on flux-folded double differential, and flux-unfolded total cross sections off 12C and compare them with MiniBooNE and (off-axis) T2K measurements. We discuss the importance of low-energy nuclear excitations for the forward bins. Conclusions: The HF and CRPA predictions describe the gross features of the measured cross sections. They underpredict the data (more in the neutrino than in the antineutrino case) because of the absence of processes beyond pure quasielastic scattering in our model. At very forward muon scattering, low-energy HF-CRPA nuclear excitations (ω <50 MeV) account for nearly 50% of the flux-folded cross section. This extra low-energy strength is a feature of the detailed microscopic nuclear model used here, that is not accessed in a Fermi-gas based approach.

  10. Cytotoxicity of nucleus-targeting fluorescent gold nanoclusters

    NASA Astrophysics Data System (ADS)

    Zhao, Jing-Ya; Cui, Ran; Zhang, Zhi-Ling; Zhang, Mingxi; Xie, Zhi-Xiong; Pang, Dai-Wen

    2014-10-01

    Gold nanoclusters (AuNCs) with ultra small sizes and unique fluorescence properties have shown promising potential for imaging the nuclei of living cells. However, little is known regarding the potential cytotoxicity of AuNCs after they enter the cell nucleus. The aim of this study is to investigate whether and how nucleus-targeting AuNCs affect the normal functioning of cells. Highly stable, water-soluble and bright fluorescent Au25NCs (the core of each nanocluster is composed of 25 gold atoms) were synthesized. Specific targeting of Au25NCs to the cell nucleus was achieved by conjugating the TAT peptide to the Au25NCs. Cell viability, cell morphology, cell apoptosis/necrosis, reactive oxygen species (ROS) level and mitochondrial membrane potential examinations were performed on different cell lines exposed to the nucleus-targeting Au25NCs. We found that the nucleus-targeting Au25NCs caused cell apoptosis in a dose-dependent manner. A possible mechanism for the cytotoxicity of the nucleus-targeting Au25NCs was proposed as follows: the nucleus-targeting Au25NCs induce the production of ROS, resulting in the oxidative degradation of mitochondrial components, in turn leading to apoptosis via a mitochondrial damage pathway. This work facilitates a better understanding of the toxicity of AuNCs, especially nucleus-targeting AuNCs.Gold nanoclusters (AuNCs) with ultra small sizes and unique fluorescence properties have shown promising potential for imaging the nuclei of living cells. However, little is known regarding the potential cytotoxicity of AuNCs after they enter the cell nucleus. The aim of this study is to investigate whether and how nucleus-targeting AuNCs affect the normal functioning of cells. Highly stable, water-soluble and bright fluorescent Au25NCs (the core of each nanocluster is composed of 25 gold atoms) were synthesized. Specific targeting of Au25NCs to the cell nucleus was achieved by conjugating the TAT peptide to the Au25NCs. Cell viability, cell

  11. 3D Protein Dynamics in the Cell Nucleus.

    PubMed

    Singh, Anand P; Galland, Rémi; Finch-Edmondson, Megan L; Grenci, Gianluca; Sibarita, Jean-Baptiste; Studer, Vincent; Viasnoff, Virgile; Saunders, Timothy E

    2017-01-10

    The three-dimensional (3D) architecture of the cell nucleus plays an important role in protein dynamics and in regulating gene expression. However, protein dynamics within the 3D nucleus are poorly understood. Here, we present, to our knowledge, a novel combination of 1) single-objective based light-sheet microscopy, 2) photoconvertible proteins, and 3) fluorescence correlation microscopy, to quantitatively measure 3D protein dynamics in the nucleus. We are able to acquire >3400 autocorrelation functions at multiple spatial positions within a nucleus, without significant photobleaching, allowing us to make reliable estimates of diffusion dynamics. Using this tool, we demonstrate spatial heterogeneity in Polymerase II dynamics in live U2OS cells. Further, we provide detailed measurements of human-Yes-associated protein diffusion dynamics in a human gastric cancer epithelial cell line.

  12. Cloud condensation nucleus-sulfate mass relationship and cloud albedo

    NASA Technical Reports Server (NTRS)

    Hegg, Dean A.

    1994-01-01

    Analysis of previously published, simultaneous measurements of cloud condensation nucleus number concentration and sulfate mass concentration suggest a nonlinear relationship between the two variables. This nonlinearity reduces the sensitivity of cloud albedo to changes in the sulfur cycle.

  13. Deconvolving the Nucleus of Centaurus A Using Chandra PSF Library

    NASA Technical Reports Server (NTRS)

    Karovska, Margarita

    2000-01-01

    Centaurus A (NGC 5128) is a giant early-type galaxy containing the nearest (at 3.5 Mpc) radio-bright Active Galactic Nucleus (AGN). Cen A was observed with the High Resolution Camera (HRC) on the Chandra X-ray Observatory on several occasions since the launch in July 1999. The high-angular resolution (less than 0.5 arcsecond) Chandra/HRC images reveal X ray multi-scale structures in this object with unprecedented detail and clarity, including the bright nucleus believed to be associated with a supermassive black hole. We explored the spatial extent of the Cen A nucleus using deconvolution techniques on the full resolution Chandra images. Model point spread functions (PSFs) were derived from the standard Chandra raytrace PSF library as well as unresolved point sources observed with Chandra. The deconvolved images show that the Cen A nucleus is resolved and asymmetric. We discuss several possible causes of this extended emission and of the asymmetries.

  14. Under Pressure: Mechanical Stress Management in the Nucleus

    PubMed Central

    Belaadi, Néjma; Aureille, Julien; Guilluy, Christophe

    2016-01-01

    Cells are constantly adjusting to the mechanical properties of their surroundings, operating a complex mechanochemical feedback, which hinges on mechanotransduction mechanisms. Whereas adhesion structures have been shown to play a central role in mechanotransduction, it now emerges that the nucleus may act as a mechanosensitive structure. Here, we review recent advances demonstrating that mechanical stress emanating from the cytoskeleton can activate pathways in the nucleus which eventually impact both its structure and the transcriptional machinery. PMID:27314389

  15. Truncal ataxia from infarction involving the inferior olivary nucleus.

    PubMed

    Park, Jae Hyun; Ryoo, Sookyung; Moon, So Young; Seo, Sand Won; Na, Duk L

    2012-08-01

    Truncal ataxia in medullary infarction may be caused by involvement of the lateral part of the medulla; however, truncal ataxia in infarction involving the inferior olivary nucleus (ION) has received comparatively little attention. We report a patient with truncal ataxia due to medial medullary infarction located in the ION. A lesion in the ION could produce a contralateral truncal ataxia due to increased inhibitory input to the contralesional vestibular nucleus from the contralesional flocculus.

  16. Radiometric observations of the nucleus of Comet Halley

    NASA Technical Reports Server (NTRS)

    Delamere, W. A.; Reitsema, H. J.; Huebner, W. F.; Schmidt, H. U.; Keller, H. U.; Schmidt, W. K. H.; Wilhelm, K.; Whipple, Fred L.

    1986-01-01

    Images obtained by the Halley multicolor camera (HMC) were used to determine the surface brightness of the nucleus. Radiometric values of jet-free areas of the surface are presented and a range of possible surface brightness values are derived. These direct measures are compared with brightnesses derived from the size of the nucleus, as determined from HMC images, and ground-based observations obtained before the onset of coma activity.

  17. The Galactic nucleus: A unique region in the Galactic ecosystem

    NASA Technical Reports Server (NTRS)

    Genzel, Reinhard; Poglitsch, Albrecht

    1995-01-01

    The nucleus is a unique region in the Galactic ecosystem. It is also superb laboratory of modern astrophysics where astronomers can study, at unprecedented spatial resolution and across the entire electromagnetic spectrum, physical processes that may also happen at the cores of other galaxies. Infrared observations from the Kuiper Airborne Observatory have made important contributions to unraveling the mysteries of the Galactic nucleus and this review highlights some of these measurements, as well as recent results regarding the central parsec.

  18. Direct and compound-nucleus reaction mechanisms in the 7Be+58Ni system at near-barrier energies

    NASA Astrophysics Data System (ADS)

    Mazzocco, M.; Torresi, D.; Pierroutsakou, D.; Keeley, N.; Acosta, L.; Boiano, A.; Boiano, C.; Glodariu, T.; Guglielmetti, A.; La Commara, M.; Lay, J. A.; Martel, I.; Mazzocchi, C.; Molini, P.; Parascandolo, C.; Pakou, A.; Parkar, V. V.; Romoli, M.; Rusek, K.; Sánchez-Benítez, A. M.; Sandoli, M.; Sgouros, O.; Signorini, C.; Silvestri, R.; Soramel, F.; Soukeras, V.; Stiliaris, E.; Strano, E.; Stroe, L.; Zerva, K.

    2015-08-01

    The energy and angular distributions of 3He and 4He ions produced in the 7Be +58Ni reaction at a bombarding energy of 22 MeV have been measured for the first time. The yield of the heavier helium isotope was four to five times more abundant than that of its lighter counterpart, ruling out the possibility that in this energy range the 7Be reaction dynamics is dominated by the exclusive breakup process 7Be→3He +4He (Sα=1.586 MeV). Extensive kinematic and theoretical calculations suggest that the 3He ions mostly originate from the 4He-stripping process and the 4He production is mainly triggered by the fusion-evaporation channel. The role played by the breakup, 3He-stripping, 1 n -stripping, and 1 n -pickup processes is also discussed.

  19. International Halley Watch: Discipline specialists for near-nucleus studies

    NASA Technical Reports Server (NTRS)

    Larson, S.; Sekanina, Z.; Rahe, J.

    1986-01-01

    The purpose of the Near-Nucleus Studies Net is to study the processes taking place in the near-nucleus environment as they relate to the nature of nucleus. This is accomplisghed by measuring the spatial and temporal distribution of dust, gases and ions in the coma on high resolution images taken from many observatories around the world. By modeling the motions of discrete dust features in Comet Halley, it is often possible to determine the locations of the emission sources on the surface and learn about the nucleus structure. In addition to the general goals shared by all IHW nets, the scientific goals of the net has been to determine (1)the gross surface structure of the nucleus, (2)the nucleus spin vector, (3)the distribution and evolution of jet sources and (4)the interrelationships between the gas, dust and ion components of the coma. An additional Comet Giacobini-Zinner watch was carried out by the NNSN in support of the NASA International Cometary Explorer flyby.

  20. A FIBER APPARATUS IN THE NUCLEUS OF THE YEAST CELL

    PubMed Central

    Robinow, C. F.; Marak, J.

    1966-01-01

    The structure and mode of division of the nucleus of budding yeast cells have been studied by phase-contrast microscopy during life and by ordinary microscopy after Helly fixation. The components of the nucleus were differentially stained by the Feulgen procedure, with Giemsa solution after hydrolysis, and with iron alum haematoxylin. New information was obtained in cells fixed in Helly's by directly staining them with 0.005% acid fuchsin in 1% acetic acid in water. Electron micrographs have been made of sections of cells that were first fixed with 3% glutaraldehyde, then divested of their walls with snail juice, and postfixed with osmium tetroxide. Light and electron microscopy have given concordant information about the organization of the yeast nucleus. A peripheral segment of the nucleus is occupied by relatively dense matter (the "peripheral cluster" of Mundkur) which is Feulgen negative. The greater part of the nucleus is filled with fine-grained Feulgen-positive matter of low density in which chromosomes could not be identified. Chromosomes become visible in this region under the light microscope at meiosis. In the chromatin lies a short fiber with strong affinity for acid fuchsin. The nucleus divides by elongation and constriction, and during this process the fiber becomes long and thin. Electron microscopy has resolved it into a bundle of dark-edged 150 to 180 A filaments which extends between "centriolar plaques" that are attached to the nuclear envelope. PMID:5331666

  1. Cytoarchitecture and saccular innervation of nucleus y in the mouse.

    PubMed

    Frederickson, C J; Trune, D R

    1986-10-15

    The cytoarchitecture and saccular innervation of the mouse nucleus y were investigated by using Golgi, Nissl, and myelin stains and anterograde axonal transport of horseradish peroxidase. Nucleus y was found to be a compact group of cells in a small fiber-free region dorsal to the restiform body. Qualitative and morphometric analyses showed that most (75%) of the nucleus y neurons could not be reliably subdivided into morphologic subgroups, but varied continuously in soma size (15-25 microns), shape (fusiform to stellate), and number of dendrites (two to four), and had sparsely branched dendrites with an average of 3 to 4 spines per 10 microns of length. Three groups of cells that were identified morphometrically accounted for 10% (type I: large stellate cells), 9% (type II: long-dendrite cells), and 6% (type III: elongated soma cells) of the y neurons. Vestibular nerve axons transporting horseradish peroxidase after injury at their origin in the saccular neuroepithelium were found to form a dense terminal meshwork that was virtually co-extensive with the cytoarchitectonic boundaries of nucleus y. Nucleus y was distinguished from the overlying infracerebellar nucleus on the basis of anatomical, cytoarchitectural, and hodological features.

  2. Suprachiasmatic Nucleus Neuropeptide Expression in Patients with Huntington's Disease

    PubMed Central

    van Wamelen, Daniel J.; Aziz, N. Ahmad; Anink, Jasper J.; van Steenhoven, Robin; Angeloni, Debora; Fraschini, Franco; Jockers, Ralf; Roos, Raymund A. C.; Swaab, Dick F.

    2013-01-01

    Study Objective: To study whether sleep and circadian rhythm disturbances in patients with Huntington's disease (HD) arise from dysfunction of the body's master clock, the hypothalamic suprachiasmatic nucleus. Design: Postmortem cohort study. Patients: Eight patients with HD and eight control subjects matched for sex, age, clock time and month of death, postmortem delay, and fixation time of paraffin-embedded hypothalamic tissue. Measurements and Results: Using postmortem paraffin-embedded tissue, we assessed the functional integrity of the suprachiasmatic nucleus in patients with HD and control subjects by determining the expression of two major regulatory neuropeptides, vasoactive intestinal polypeptide and arginine vasopressin. Additionally, we studied melatonin 1 and 2 receptor expression. Compared with control subjects, the suprachiasmatic nucleus contained 85% fewer neurons immunoreactive for vasoactive intestinal polypeptide and 33% fewer neurons for arginine vasopressin in patients with HD (P = 0.002 and P = 0.027). The total amount of vasoactive intestinal polypeptide and arginine vasopressin messenger RNA was unchanged. No change was observed in the number of melatonin 1 or 2 receptor immunoreactive neurons. Conclusions: These findings indicate posttranscriptional neuropeptide changes in the suprachiasmatic nucleus of patients with HD, and suggest that sleep and circadian rhythm disorders in these patients may at least partly arise from suprachiasmatic nucleus dysfunction. Citation: van Wamelen DJ; Aziz NA; Anink JJ; van Steenhoven R; Angeloni D; Fraschini F; Jockers R; Roos RAC; Swaab DF. Suprachiasmatic nucleus neuropeptide expression in patients with Huntington's disease. SLEEP 2013;36(1):117–125. PMID:23288978

  3. 3200 Phaethon, Asteroid or Comet Nucleus?

    NASA Astrophysics Data System (ADS)

    Boice, Daniel C.; Benkhoff, Johannes

    2015-08-01

    Physico-chemical modeling is central to understand the important physical processes in small solar system bodies. We have developed a computer simulation, SUISEI, that includes the physico-chemical processes relevant to comets within a global modeling framework. Our goals are to gain valuable insights into the intrinsic properties of cometary nuclei so we can better understand observations and in situ measurements. SUISEI includes a 3-D model of gas and heat transport in porous sub-surface layers in the interior of the nucleus.We present results on the application of SUISEI to the near-Sun object, Phaethon. Discovered in 1983 and classified as an asteroid, it has recently exhibited an active dust coma. Phaethon has long been associated as the source of the Geminids meteor shower so the dust activity provides a clear link to the meteor shower. The observed dust activity would traditionally lead to Phaethon being also classified as a comet (e.g., 2060-95P/Chiron, 133P/Elst-Pizarro). This is unusual since the orbit of Phaethon has a perihelion of 0.14 AU, resulting in surface temperatures of more than 1025K, much too hot for water ice or other volatiles to exist near the surface and drive the activity. This situation and others such as the “Active Asteroids” necessitates a revision of how we understand and classify these small asteroid-comet transition objects.We conclude the following for Phaethon:1. It is likely to contain relatively pristine volatiles in its interior despite repeated near perihelion passages of 0.14 AU during its history in its present orbit,2. Steady water gas fluxes at perihelion and throughout its orbit are insufficient to entrain the currently observed dust production,3. Thermal gradients into the surface as well as those caused by diurnal rotation are consistent with the mechanism of dust release due to thermal fracture,4. The initial large gas release during the first perihelion passage may be sufficient to produce enough dust to explain

  4. Low-energy modification of the γ strength function of the odd-even nucleus 115In

    NASA Astrophysics Data System (ADS)

    Versteegen, Maud; Denis-Petit, David; Méot, Vincent; Bonnet, Thomas; Comet, Maxime; Gobet, Franck; Hannachi, Fazia; Tarisien, Medhi; Morel, Pascal; Martini, Marco; Péru, Sophie

    2016-10-01

    Photoactivation yield measurements on 115In have been performed at the ELSA facility with Bremsstrahlung photon beams over a range of endpoint energies between 4.5 and 18 MeV. The measured photoexcitation yields of the Inm115 metastable state are compared with calculated yields using cross sections obtained with different models of the photon strength function. It is shown that additional photon strength with respect to the general Lorentzian model is needed at 8.1 MeV for the calculated yields to reproduce the data. The origin of this extra strength is unclear, because it is compatible with additional strength predicted in both E 1 and M 1 photon strength distributions by quasiparticle random-phase approximation calculations using the Gogny D1S force.

  5. GLP-1R Signaling Directly Activates Arcuate Nucleus Kisspeptin Action in Brain Slices but Does not Rescue Luteinizing Hormone Inhibition in Ovariectomized Mice During Negative Energy Balance.

    PubMed

    Heppner, Kristy M; Baquero, Arian F; Bennett, Camdin M; Lindsley, Sarah R; Kirigiti, Melissa A; Bennett, Baylin; Bosch, Martha A; Mercer, Aaron J; Rønnekleiv, Oline K; True, Cadence; Grove, Kevin L; Smith, M Susan

    2017-01-01

    Kisspeptin (Kiss1) neurons in the hypothalamic arcuate nucleus (ARC) are key components of the hypothalamic-pituitary-gonadal axis, as they regulate the basal pulsatile release of gonadotropin releasing hormone (GnRH). ARC Kiss1 action is dependent on energy status, and unmasking metabolic factors responsible for modulating ARC Kiss1 neurons is of great importance. One possible factor is glucagon-like peptide 1 (GLP-1), an anorexigenic neuropeptide produced by brainstem preproglucagon neurons. Because GLP fiber projections and the GLP-1 receptor (GLP-1R) are abundant in the ARC, we hypothesized that GLP-1R signaling could modulate ARC Kiss1 action. Using ovariectomized mice, we found that GLP-producing fibers come in close apposition with ARC Kiss1 neurons; these neurons also contain Glp1r mRNA. Electrophysiological recordings revealed that liraglutide (a long-acting GLP-1R agonist) increased action potential firing and caused a direct membrane depolarization of ARC Kiss1 cells in brain slices. We determined that brainstem preproglucagon mRNA is decreased after a 48-h fast in mice, a negative energy state in which ARC Kiss1 expression and downstream GnRH/luteinizing hormone (LH) release are potently suppressed. However, activation of GLP-1R signaling in fasted mice with liraglutide was not sufficient to prevent LH inhibition. Furthermore, chronic central infusions of the GLP-1R antagonist, exendin(9-39), in ad libitum-fed mice did not alter ARC Kiss1 mRNA or plasma LH. As a whole, these data identify a novel interaction of the GLP-1 system with ARC Kiss1 neurons but indicate that CNS GLP-1R signaling alone is not critical for the maintenance of LH during fasting or normal feeding.

  6. GLP-1R Signaling Directly Activates Arcuate Nucleus Kisspeptin Action in Brain Slices but Does not Rescue Luteinizing Hormone Inhibition in Ovariectomized Mice During Negative Energy Balance

    PubMed Central

    Heppner, Kristy M.; Baquero, Arian F.; True, Cadence; Grove, Kevin L.

    2017-01-01

    Abstract Kisspeptin (Kiss1) neurons in the hypothalamic arcuate nucleus (ARC) are key components of the hypothalamic-pituitary-gonadal axis, as they regulate the basal pulsatile release of gonadotropin releasing hormone (GnRH). ARC Kiss1 action is dependent on energy status, and unmasking metabolic factors responsible for modulating ARC Kiss1 neurons is of great importance. One possible factor is glucagon-like peptide 1 (GLP-1), an anorexigenic neuropeptide produced by brainstem preproglucagon neurons. Because GLP fiber projections and the GLP-1 receptor (GLP-1R) are abundant in the ARC, we hypothesized that GLP-1R signaling could modulate ARC Kiss1 action. Using ovariectomized mice, we found that GLP-producing fibers come in close apposition with ARC Kiss1 neurons; these neurons also contain Glp1r mRNA. Electrophysiological recordings revealed that liraglutide (a long-acting GLP-1R agonist) increased action potential firing and caused a direct membrane depolarization of ARC Kiss1 cells in brain slices. We determined that brainstem preproglucagon mRNA is decreased after a 48-h fast in mice, a negative energy state in which ARC Kiss1 expression and downstream GnRH/luteinizing hormone (LH) release are potently suppressed. However, activation of GLP-1R signaling in fasted mice with liraglutide was not sufficient to prevent LH inhibition. Furthermore, chronic central infusions of the GLP-1R antagonist, exendin(9–39), in ad libitum–fed mice did not alter ARC Kiss1 mRNA or plasma LH. As a whole, these data identify a novel interaction of the GLP-1 system with ARC Kiss1 neurons but indicate that CNS GLP-1R signaling alone is not critical for the maintenance of LH during fasting or normal feeding. PMID:28144621

  7. Maruhn-Greiner Maximum for Confirmation of Low Energy Nuclear Reactions (LENR) via a Compound Nucleus with Double Magic Numbers

    NASA Astrophysics Data System (ADS)

    Hora, Heinrich; Miley, George

    2007-03-01

    One of the most convincing facts about LENR due to deuterons (ds) or protons of very high concentration in host metals of palladium is the measurement of the large scale minimum in the reaction probability with product elements centered around the nucleon number A = 153. The local maximum was measured in this region is similar to fission of uranium at A = 119 where the local maximum follows the Maruhn-Greiner mechanism^1. We suggest this phenomenon can be explained by the strong screening of the Maxwellian ds on the degenerate rigid electron background within the swimming electrons at the metal surface or thin filem interfaces. The deuterons behave like neutrals at distances of above 2 picometers (pm) and form clusters due to soft attraction in the range of thermal energy; 10 pm diameter clusters can react over long time scales (10^6 s) with Pd leading to double magic number compound nuclei 306x126 decaying via fission to an A=153 element distribution. J. Maruhn et al, Phys. Rev. Letters 32, 548 (1974) H. Hora, G.H. Miley, CzechJ. Phys. 48, 1111 (1998)

  8. Nucleus-Dependent Valence-Space Approach to Nuclear Structure

    NASA Astrophysics Data System (ADS)

    Stroberg, S. R.; Calci, A.; Hergert, H.; Holt, J. D.; Bogner, S. K.; Roth, R.; Schwenk, A.

    2017-01-01

    We present a nucleus-dependent valence-space approach for calculating ground and excited states of nuclei, which generalizes the shell-model in-medium similarity renormalization group to an ensemble reference with fractionally filled orbitals. Because the ensemble is used only as a reference, and not to represent physical states, no symmetry restoration is required. This allows us to capture three-nucleon (3 N ) forces among valence nucleons with a valence-space Hamiltonian specifically targeted to each nucleus of interest. Predicted ground-state energies from carbon through nickel agree with results of other large-space ab initio methods, generally to the 1% level. In addition, we show that this new approach is required in order to obtain convergence for nuclei in the upper p and s d shells. Finally, we address the 1+/3+ inversion problem in 22Na and 46V. This approach extends the reach of ab initio nuclear structure calculations to essentially all light- and medium-mass nuclei.

  9. Some morphological features of a visual thalamic nucleus in a reptile: observations on nucleus rotundus in Caiman crocodilus.

    PubMed

    Pritz, M B

    1997-01-01

    The morphology of nucleus rotundus, a visual thalamic nucleus, was investigated in one species of reptiles. Caiman crocodilus, using Nisst stained material in transverse, sagittal, and horizontal planes. The topographical location of nucleus rotundus and its relationship to surrounding thalamic nuclear groups are described. Nucleus rotundus in Caiman can be subdivided into three areas: (1) an outer shell; (2) an inner core; and (3) a cell poor zone located between the shell and core. Most rotundal core neurons were round, fusiform, triangular, pear-shaped, or elliptical. Core neurons were not distributed evenly throughout the nucleus but, in many instances, were arranged in clusters composed of two to ten neurons. Quantitative measurements of area, perimeter, and eccentricity (greatest width/greatest length), which served as an index of cell roundness, were made on rotundal core neuron profiles in transverse, sagittal, and horizontal planes of section. Qualitative and quantitative observations were not appreciably different regardless of the plane of orientation. Both qualitative and quantitative data suggest that relay cells located in the core of nucleus rotundus are not a homogeneous population of neurons but comprise several subtypes.

  10. The interfascicular trigeminal nucleus: a precerebellar nucleus in the mouse defined by retrograde neuronal tracing and genetic fate mapping.

    PubMed

    Fu, Yuhong; Tvrdik, Petr; Makki, Nadja; Machold, Robert; Paxinos, George; Watson, Charles

    2013-02-15

    We have found a previously unreported precerebellar nucleus located among the emerging fibers of the motor root of the trigeminal nerve in the mouse, which we have called the interfascicular trigeminal nucleus (IF5). This nucleus had previously been named the tensor tympani part of the motor trigeminal nucleus (5TT) in rodent brain atlases, because it was thought to be a subset of small motor neurons of the motor trigeminal nucleus innervating the tensor tympani muscle. However, following injection of retrograde tracer in the cerebellum, the labeled neurons in IF5 were found to be choline acetyltransferase (ChAT) negative, indicating that they are not motor neurons. The cells of IF5 are strongly labeled in mice from Wnt1Cre and Atoh1 CreER lineage fate mapping, in common with the major precerebellar nuclei that arise from the rhombic lip and that issue mossy fibers. Analysis of sections from mouse Hoxa3, Hoxb1, and Egr2 Cre labeled lineages shows that the neurons of IF5 arise from rhombomeres caudal to rhombomere 4, most likely from rhombomeres 6-8. We conclude that IF5 is a significant precerebellar nucleus in the mouse that shares developmental gene expression characteristics with mossy fiber precerebellar nuclei that arise from the caudal rhombic lip.

  11. The turtle thalamic anterior entopeduncular nucleus shares connectional and neurochemical characteristics with the mammalian thalamic reticular nucleus.

    PubMed

    Kenigfest, Natalia; Belekhova, Margarita; Repérant, Jacques; Rio, Jean Paul; Ward, Roger; Vesselkin, Nikolai

    2005-10-01

    Neurochemical and key connectional characteristics of the anterior entopeduncular nucleus (Enta) of the turtle (Testudo horsfieldi) were studied by axonal tracing techniques and immunohistochemistry of parvalbumin, gamma-aminobutyric acid (GABA) and glutamic acid decarboxylase (GAD). We showed that the Enta, which is located within the dorsal peduncle of the lateral forebrain bundle (Pedd), has roughly topographically organized reciprocal connections with the dorsal thalamic visual nuclei, the nucleus rotundus (Rot) and dorsal lateral geniculate nucleus (GLd). The Enta receives projections from visual telencephalic areas, the anterior dorsal ventricular ridge and dorsolateral cortex/pallial thickening. Most Enta neurons contained GABA and parvalbumin, and some of them were retrogradely labeled when the tracer was injected into the visual dorsal thalamic nuclei. Further experiments using double immunofluorescence revealed colocalization of GAD and parvalbumin in the vast majority of Enta neurons, and many of these cells showed retrograde labeling with Fluoro-gold injected into the Rot and/or GLd. According to these data, the Enta may be considered as a structural substrate for recurrent inhibition of the visual thalamic nuclei. Based on morphological and neurochemical similarity of the turtle Enta, caiman Pedd nucleus, the superior reticular nucleus in birds, and the thalamic reticular nucleus in mammals, we suggest that these structures represent a characteristic component which is common to the thalamic organization in amniotes.

  12. One-pion production in neutrino-nucleus collisions

    SciTech Connect

    Hernández, E.; Nieves, J.; Vicente-Vacas, J. M.

    2015-05-15

    We use our model for neutrino pion production on the nucleon to study pion production on a nucleus. The model is conveniently modified to include in-medium corrections and its validity is extended up to 2 GeV neutrino energies by the inclusion of new resonant contributions in the production process. Our results are compared with recent MiniBooNE data measured in mineral oil. Our total cross sections are below data for neutrino energies above ≈ 1 GeV. As with other theoretical calculations, the agreement with data improves if we neglect pion final state interaction. This is also the case for differential cross sections convoluted over the neutrino flux.

  13. The red nucleus and the rubrospinal projection in the mouse.

    PubMed

    Liang, Huazheng; Paxinos, George; Watson, Charles

    2012-04-01

    We studied the organization and spinal projection of the mouse red nucleus with a range of techniques (Nissl stain, immunofluorescence, retrograde tracer injections into the spinal cord, anterograde tracer injections into the red nucleus, and in situ hybridization) and counted the number of neurons in the red nucleus (3,200.9 ± 230.8). We found that the rubrospinal neurons were mainly located in the parvicellular region of the red nucleus, more lateral in the rostral part and more medial in the caudal part. Labeled neurons were least common in the rostral and caudal most parts of the red nucleus. Neurons projecting to the cervical cord were predominantly dorsomedially placed and neurons projecting to the lumbar cord were predominantly ventrolaterally placed. Immunofluorescence staining with SMI-32 antibody showed that ~60% of SMI-32-positive neurons were cervical cord-projecting neurons and 24% were lumbar cord-projecting neurons. SMI-32-positive neurons were mainly located in the caudomedial part of the red nucleus. A study of vGluT2 expression showed that the number and location of glutamatergic neurons matched with those of the rubrospinal neurons. In the anterograde tracing experiments, rubrospinal fibers travelled in the dorsal portion of the lateral funiculus, between the lateral spinal nucleus and the calretinin-positive fibers of the lateral funiculus. Rubrospinal fibers terminated in contralateral laminae 5, 6, and the dorsal part of lamina 7 at all spinal cord levels. A few fibers could be seen next to the neurons in the dorsolateral part of lamina 9 at levels of C8-T1 (hand motor neurons) and L5-L6 (foot motor neurons), which is consistent with a view that rubrospinal fibers may play a role in distal limb movement in rodents.

  14. The subthalamic nucleus influences visuospatial attention in humans.

    PubMed

    Schmalbach, Barbara; Günther, Veronika; Raethjen, Jan; Wailke, Stefanie; Falk, Daniela; Deuschl, Günther; Witt, Karsten

    2014-03-01

    Spatial attention is a lateralized feature of the human brain. Whereas the role of cortical areas of the nondominant hemisphere on spatial attention has been investigated in detail, the impact of the BG, and more precisely the subthalamic nucleus, on signs and symptoms of spatial attention is not well understood. Here we used unilateral deep brain stimulation of the subthalamic nucleus to reversibly, specifically, and intraindividually modify the neuronal BG outflow and its consequences on signs and symptoms of visuospatial attention in patients suffering from Parkinson disease. We tested 13 patients with Parkinson disease and chronic deep brain stimulation in three stimulation settings: unilateral right and left deep brain stimulation of the subthalamic nucleus as well as bilateral deep brain stimulation of the subthalamic nucleus. In all three stimulation settings, the patients viewed a set of pictures while an eye-tracker system recorded eye movements. During the exploration of the visual stimuli, we analyzed the time spent in each visual hemispace, as well as the number, duration, amplitude, peak velocity, acceleration peak, and speed of saccades. In the unilateral left-sided stimulation setting, patients show a shorter ipsilateral exploration time of the extrapersonal space, whereas number, duration, and speed of saccades did not differ between the different stimulation settings. These results demonstrated reduced visuospatial attention toward the side contralateral to the right subthalamic nucleus that was not being stimulated in a unilateral left-sided stimulation. Turning on the right stimulator, the reduced visuospatial attention vanished. These results support the involvement of the subthalamic nucleus in modulating spatial attention. Therefore, the subthalamic nucleus is part of the subcortical network that subserves spatial attention.

  15. Spectral energy distributions of QSOs at z > 5: Common active galactic nucleus-heated dust and occasionally strong star-formation

    SciTech Connect

    Leipski, C.; Meisenheimer, K.; Walter, F.; Klaas, U.; Krause, O.; Rix, H.-W.; Dannerbauer, H.; De Rosa, G.; Fan, X.; Haas, M.

    2014-04-20

    We present spectral energy distributions (SEDs) of 69 QSOs at z > 5, covering a rest frame wavelength range of 0.1 μm to ∼80 μm, and centered on new Spitzer and Herschel observations. The detection rate of the QSOs with Spitzer is very high (97% at λ{sub rest} ≲ 4 μm), but drops toward the Herschel bands with 30% detected in PACS (rest frame mid-infrared) and 15% additionally in the SPIRE (rest frame far-infrared; FIR). We perform multi-component SED fits for Herschel-detected objects and confirm that to match the observed SEDs, a clumpy torus model needs to be complemented by a hot (∼1300 K) component and, in cases with prominent FIR emission, also by a cold (∼50 K) component. In the FIR-detected cases the luminosity of the cold component is of the order of 10{sup 13} L {sub ☉} which is likely heated by star formation. From the SED fits we also determine that the active galactic nucleus (AGN) dust-to-accretion disk luminosity ratio declines with UV/optical luminosity. Emission from hot (∼1300 K) dust is common in our sample, showing that nuclear dust is ubiquitous in luminous QSOs out to redshift 6. However, about 15% of the objects appear under-luminous in the near infrared compared to their optical emission and seem to be deficient in (but not devoid of) hot dust. Within our full sample, the QSOs detected with Herschel are found at the high luminosity end in L {sub UV/opt} and L {sub NIR} and show low equivalent widths (EWs) in Hα and in Lyα. In the distribution of Hα EWs, as determined from the Spitzer photometry, the high-redshift QSOs show little difference to low-redshift AGN.

  16. Dynamic, mechanical integration between nucleus and cell- where physics meets biology.

    PubMed

    Dickinson, Richard B; Neelam, Srujana; Lele, Tanmay P

    2015-01-01

    Nuclear motions like rotation, translation and deformation suggest that the nucleus is acted upon by mechanical forces. Molecular linkages with the cytoskeleton are thought to transfer forces to the nuclear surface. We developed an approach to apply reproducible, known mechanical forces to the nucleus in spread adherent cells and quantified the elastic response of the mechanically integrated nucleus-cell. The method is sensitive to molecular perturbations and revealed new insight into the function of the LINC complex. While these experiments revealed elastic behaviors, turnover of the cytoskeleton by assembly/disassembly and binding/unbinding of linkages are expected to dissipate any stored mechanical energy in the nucleus or the cytoskeleton. Experiments investigating nuclear forces over longer time scales demonstrated the mechanical principle that expansive/compressive stresses on the nuclear surface arise from the movement of the cell boundaries to shape and position the nucleus. Such forces can shape the nucleus to conform to cell shapes during cell movements with or without myosin activity.

  17. The midbrain precommand nucleus of the mormyrid electromotor network.

    PubMed

    von der Emde, G; Sena, L G; Niso, R; Grant, K

    2000-07-15

    The functional role of the midbrain precommand nucleus (PCN) of the electromotor system was explored in the weakly electric mormyrid fish Gnathonemus petersii, using extracellular recording of field potentials, single unit activity, and microstimulation in vivo. Electromotor-related field potentials in PCN are linked in a one-to-one manner and with a fixed time relationship to the electric organ discharge (EOD) command cycle, but occur later than EOD command activity in the medulla. It is suggested that PCN electromotor-related field potentials arise from two sources: (1) antidromically, by backpropagation across electrotonic synapses between PCN axons and command nucleus neurons, and (2) as corollary discharge-driven feedback arriving from the command nucleus indirectly, via multisynaptic pathways. PCN neurons can be activated by electrosensory input, but this does not necessarily activate the whole motor command chain. Microstimulation of PCN modulates the endogenous pattern of electromotor command in a way that can mimic the structure of certain stereotyped behavioral patterns. PCN activity is regulated, and to a certain extent synchronized, by corollary discharge feedback inhibition. However, PCN does not generally function as a synchronized pacemaker driving the electromotor command chain. We propose that PCN neurons integrate information of various origins and individually relay this to the command nucleus in the medulla. Some may also have intrinsic, although normally nonsynchronized, pacemaker properties. This descending activity, integrated in the electromotor command nucleus, will play an important modulatory role in the central pattern generator decision process.

  18. Coordinated Dynamics of RNA Splicing Speckles in the Nucleus.

    PubMed

    Zhang, Qiao; Kota, Krishna P; Alam, Samer G; Nickerson, Jeffrey A; Dickinson, Richard B; Lele, Tanmay P

    2016-06-01

    Despite being densely packed with chromatin, nuclear bodies and a nucleoskeletal network, the nucleus is a remarkably dynamic organelle. Chromatin loops form and relax, RNA transcripts and transcription factors move diffusively, and nuclear bodies move. We show here that RNA splicing speckled domains (splicing speckles) fluctuate in constrained nuclear volumes and remodel their shapes. Small speckles move in a directed way toward larger speckles with which they fuse. This directed movement is reduced upon decreasing cellular ATP levels or inhibiting RNA polymerase II activity. The random movement of speckles is reduced upon decreasing cellular ATP levels, moderately reduced after inhibition of SWI/SNF chromatin remodeling and modestly increased upon inhibiting RNA polymerase II activity. To define the paths through which speckles can translocate in the nucleus, we generated a pressure gradient to create flows in the nucleus. In response to the pressure gradient, speckles moved along curvilinear paths in the nucleus. Collectively, our results demonstrate a new type of ATP-dependent motion in the nucleus. We present a model where recycling splicing factors return as part of small sub-speckles from distal sites of RNA processing to larger splicing speckles by a directed ATP-driven mechanism through interchromatin spaces.

  19. Growth dynamics of the developing lateral geniculate nucleus.

    PubMed

    Williams, A L; Jeffery, G

    2001-02-12

    Segregated binocular maps in the lateral geniculate nucleus (LGN) develop from stages where they initially completely overlap. Here, we show that segregation occurs at different rates across the depth of the nucleus and that the volume of the ipsilateral projection does not decrease significantly during this period, rather LGN volume expands markedly and its shape changes. Hence, we have examined the differential growth of the ferret LGN during the process of segregation by using novel shape modelling techniques. These have facilitated quantification of its three-dimensional structure at successive developmental stages as well as the definition of growth vectors which illustrate shape change. This has been undertaken in direct representations of the LGN and those normalised for size and orientation. Spatiotemporal aspects of shape change have then been compared with different measurements of its cellular population. Initial stages of segregation are associated with a large expansion of the rostrocaudal axis of the nucleus along which segregation takes place, and an expansion of caudal regions that will eventually contain the binocular representation. Later stages are associated with dorsoventral expansions and a consolidation of the rostrocaudal axis. The pace of shape change peaks toward the end of the period of segregation when the nucleus has adopted approximately 50% of its adult shape. After segregation, nuclear growth is mainly isotropic. The mature shape of the nucleus is achieved before it reaches its full size and while cell density and cell sizes are still changing.

  20. Reactions with the double-Borromean nucleus He8

    NASA Astrophysics Data System (ADS)

    Lemasson, A.; Navin, A.; Keeley, N.; Rejmund, M.; Bhattacharyya, S.; Shrivastava, A.; Bazin, D.; Beaumel, D.; Blumenfeld, Y.; Chatterjee, A.; Gupta, D.; de France, G.; Jacquot, B.; Labiche, M.; Lemmon, R.; Nanal, V.; Nyberg, J.; Pillay, R. G.; Raabe, R.; Ramachandran, K.; Scarpaci, J. A.; Simenel, C.; Stefan, I.; Timis, C. N.

    2010-10-01

    Differential cross sections for elastic-scattering and neutron-transfer reactions along with cross sections for fusion in the He8+Cu65 system are reported at energies above the Coulomb barrier (Elab= 19.9 and 30.6 MeV). The present work demonstrates the feasibility of using inclusive measurements of characteristic in-beam γ rays with low-intensity (~105 pps) radioactive ion beams to obtain the residue cross sections for fusion and neutron transfer. Exclusive measurements of γ rays in coincidence with light charged particles have been used to further characterize the direct reactions induced by this double-Borromean nucleus. Coupled reaction channels calculations are used to illustrate the important role played by the transfer channels and to help in understanding the influence of the structure of He8 on the reaction mechanism.

  1. Total absorption spectroscopy of N = 51 nucleus 85Se

    NASA Astrophysics Data System (ADS)

    Goetz, K. C.; Grzywacz, R. K.; Rykaczewski, K. P.; Karny, M.; Fialkowska, A.; Wolinska-Cichocka, M.; Rasco, B. C.; Zganjar, E. F.; Johnson, J. W.; Gross, C. J.

    2014-09-01

    An experimental campaign utilizing the Modular Total Absorption Spectrometer (MTAS) was conducted at the HRIBF facility in January of 2012. The campaign studied 22 isotopes, many of which were identified as the highest priority for decay heat analysis during a nuclear fuel cycle, see the report by the OECD-IAEA Nuclear Energy Agency in 2007. The case of 85Se will be discussed. 85Se is a Z = 34, N = 51 nucleus with the valence neutron located in the positive parity sd single particle state. Therefore, its decay properties are determined by interplay between first forbidden decays of the valence neutron and Gamow-Teller decay of a 78Ni core. Analysis of the data obtained during the January 2012 run indicates a significant increase of the beta strength function when compared with previous measurements, see Ref..

  2. Nucleus of Comet IRAS-Araki-Alcock (1983 VII)

    SciTech Connect

    Sekanina, Z.

    1988-06-01

    Optical, radar, infrared, UV, and microwave-continuum observations of Comet IRAS-Araki-Alcok were obtained in May 1983, the week of the comet's close approach to earth. The comet has a nucleus dimension and a rotation period which are similar to those of Comet Halley, but a different morphological signature (a persisting sunward fan-shaped coma). Time variations are noted in the projected nucleus cross section. Results suggest significant limb-darkening effects in the relevant domains of radio waves, and that the comet's interior must be extremely cold. It is found that the thermal-infrared fluxes from the inner coma of the comet are dominated by the nucleus. 63 references.

  3. The Potential Roles of Actin in The Nucleus

    PubMed Central

    Falahzadeh, Khadijeh; Banaei-Esfahani, Amir; Shahhoseini, Maryam

    2015-01-01

    Over the past few decades, actin’s presence in the nucleus has been demonstrated. Actin is a key protein necessary for different nuclear processes. Although actin is well known for its functional role in dynamic behavior of the cytoskeleton, emerging studies are now highlighting new roles for actin. At the present time there is no doubt about the presence of actin in the nucleus. A number of studies have uncovered the functional involvement of actin in nuclear processes. Actin as one of the nuclear components has its own structured and functional rules, such as nuclear matrix association, chromatin remodeling, transcription by RNA polymerases I, II, III and mRNA processing. In this historical review, we attempt to provide an overview of our current understanding of the functions of actin in the nucleus. PMID:25870830

  4. Reaction cross sections of the deformed halo nucleus 31Ne

    NASA Astrophysics Data System (ADS)

    Urata, Y.; Hagino, K.; Sagawa, H.

    2012-10-01

    Using the Glauber theory, we calculate reaction cross sections for the deformed halo nucleus 31Ne. To this end, we assume that the 31Ne nucleus takes the 30Ne+n structure. To take into account the rotational excitation of the core nucleus 30Ne, we employ the particle-rotor model (PRM). We compare the results to those in the adiabatic limit of PRM, that is, the Nilsson model, and show that the Nilsson model works reasonably well for the reaction cross sections of 31Ne. We also investigate the dependence of the reaction cross sections on the ground-state properties of 31Ne, such as the deformation parameter and the p-wave component in the ground-state wave function.

  5. Response Properties of Cochlear Nucleus Neurons in Monkeys

    PubMed Central

    Roth, G. Linn; Recio, A.

    2009-01-01

    Much of what is known about how the cochlear nuclei participate in mammalian hearing comes from studies of non-primate mammalian species. To determine to what extent the cochlear nuclei of primates resemble those of other mammalian orders, we have recorded responses to sound in three primate species: marmosets, Cynomolgus macaques, and squirrel monkeys. These recordings show that the same types of temporal firing patterns are found in primates that have been described in other mammals. Responses to tones of neurons in the ventral cochlear nucleus have similar tuning, latencies, post-stimulus time and interspike interval histograms as those recorded in non-primate cochlear nucleus neurons. In the dorsal cochlear nucleus, too, responses were similar. From these results it is evident that insights gained from non-primate studies can be applied to the peripheral auditory system of primates. PMID:19531377

  6. Figure Caption for pair of images of 'Comet Nucleus Q

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Figure Caption for pair of images of 'Comet Nucleus Q'. 21Jul94 Last Look at the Q-nuclei First image - March 30, 1994. Two Q-nuclei and a split nucleus, P. Second image - July 20, 1994. at T - 10 hours. Both nuclei still show no sign of further fragmentation, although the coma near each is being stretched out along the direction of motion. Both images were taken with the WFPC2 Planetary Camera using a red filter. Credit: H. A. Weaver and T. E. Smith

  7. Morphology of multiple-nucleus brightest cluster galaxies

    SciTech Connect

    Lauer, T.R.

    1988-02-01

    The morphology of high SNR CCD images of 16 multiple-nucleus brightest cluster galaxies is studied using an algorithm that models images of the systems as the line-of-sight superposition of normal elliptical galaxies. The algorithm is applied initially to the classic multiple-nucleus cD galaxy in A2199. Evidence is found suggestive of deep interpenetrating high-speed encounters by its secondaries. The interactions effects studied include noncentric isophotes, brightness profile effects, excess light around primary galaxies, and dynamical friction wakes. The results show that in many cases multiple systems are interacting systems. 42 references.

  8. The morphology of multiple-nucleus brightest cluster galaxies

    NASA Technical Reports Server (NTRS)

    Lauer, Tod R.

    1988-01-01

    The morphology of high SNR CCD images of 16 multiple-nucleus brightest cluster galaxies is studied using an algorithm that models images of the systems as the line-of-sight superposition of normal elliptical galaxies. The algorithm is applied initially to the classic multiple-nucleus cD galaxy in A2199. Evidence is found suggestive of deep interpenetrating high-speed encounters by its secondaries. The interactions effects studied include noncentric isophotes, brightness profile effects, excess light around primary galaxies, and dynamical friction wakes. The results show that in many cases multiple systems are interacting systems.

  9. The Development of Hypertrophic Inferior Olivary Nucleus in Oculopalatal Tremor.

    PubMed

    Jun, Bokkwan

    2016-12-01

    Oculopalatal tremor is an acquired clinical condition resulting from the interruption of the dentato-rubro-olivary neuronal pathway. The signal change in inferior olivary nucleus and its hypertrophy on magnetic resonance imaging (MRI) can be observed prior to the development of symptomatic oculopalatal tremor. This is a case of the fourth cranial nerve palsy followed by oculopalatal tremor, and increased signal intensity in inferior olivary nucleus on MRI was observed in 7 months after damage to the dentate-rubro-olivary pathway and 5 months prior to the development of oscillopsia and oculopalatal tremor.

  10. Ice crystal and ice nucleus measurements in cap clouds

    NASA Technical Reports Server (NTRS)

    Vali, G.; Rogers, D. C.; Deshler, T. L.

    1982-01-01

    Ice nucleation in cap clouds over a mountain in Wyoming was examined with airborne instrumentation. Crosswind and wind parallel passes were made through the clouds, with data being taken on the ice crystal concentrations and sizes. A total of 141 penetrations of 26 separate days in temperatures ranging from -7 to -24 C were performed. Subsequent measurements were also made 100 km away from the mountain. The ice crystal concentrations measured showed good correlation with the ice nucleus content in winter time, midcontinental air masses in Wyoming. Further studies are recommended to determine if the variations in the ice nucleus population are the cause of the variability if ice crystal content.

  11. Analysis of organic compounds in returned comet nucleus samples

    NASA Technical Reports Server (NTRS)

    Cronin, J. R.

    1989-01-01

    Techniques for analysis of organic compounds in returned comet nucleus samples are described. Interstellar, chondritic and transitional organic components are discussed. Appropriate sampling procedures will be essential to the success of these analyses. It will be necessary to return samples that represent all the various regimes found in the nucleus, e.g., a complete core, volatile components (deep interior), and crustal components (surface minerals, rocks, processed organics such as macromolecular carbon and polymers). Furthermore, sampling, storage, return, and distribution of samples must be done under conditions that preclude contamination of the samples by terrestrial matter.

  12. Dual efferent projections of the trigeminal principal sensory nucleus to the thalamic ventroposteromedial nucleus in the squirrel monkey.

    PubMed

    Ganchrow, D; Mehler, W R

    1986-07-24

    Anterograde degeneration methods demonstrated two efferent components from the trigeminal principal sensory nucleus (PrV) to the thalamic ventroposteromedial nucleus (VPM) in the squirrel monkey: fibers from the dorsal PrV coursed within the central tegmental tract and terminated in a dorsoventromedial strip of the ipsilateral VPM; fibers from the ventral PrV mainly decussated caudal to the interpeduncular nucleus and terminated in the contralateral VPM exclusive of the sector receiving the dorsal PrV component, contralaterally. Adjacent Nissl sections showed an apparent increase in glial profiles accompanying an intense somal staining among the deafferented neuronal population in the VPM, coextensive with those regions in the VPM exhibiting terminal field degeneration.

  13. Micro-structural Change During Nucleation: From Nucleus To Bicontinuous Morphology

    PubMed Central

    Jeong, Seongmin; Jho, Yongseok; Zhou, Xin

    2015-01-01

    Although the microstructure of coexistence phase provides direct insights of the nucleation mechanism and their change is substantial in the phase transition, their study is limited due to the lack of suitable tools capturing the thermodynamically unstable transient states. We resolve this problem in computational study by introducing a generalized canonical ensemble simulation and investigate the morphological change of the nucleus during the water evaporation and condensation. We find that at very low pressure, where the transition is first order, classical nucleation theory holds approximately. A main nucleus is formed in the supersaturation near spinodal, and the overall shape of the nucleus is finite and compact. On increasing the pressure of the system, more nuclei are formed even before spinodal. They merge into a larger nuclei with a smaller free energy penalty to form ramified shapes. We suggest order parameters to describe the extent of fluctuation, and their relation to the free energy profile. PMID:26526871

  14. Micro-structural Change During Nucleation: From Nucleus To Bicontinuous Morphology

    NASA Astrophysics Data System (ADS)

    Jeong, Seongmin; Jho, Yongseok; Zhou, Xin

    2015-11-01

    Although the microstructure of coexistence phase provides direct insights of the nucleation mechanism and their change is substantial in the phase transition, their study is limited due to the lack of suitable tools capturing the thermodynamically unstable transient states. We resolve this problem in computational study by introducing a generalized canonical ensemble simulation and investigate the morphological change of the nucleus during the water evaporation and condensation. We find that at very low pressure, where the transition is first order, classical nucleation theory holds approximately. A main nucleus is formed in the supersaturation near spinodal, and the overall shape of the nucleus is finite and compact. On increasing the pressure of the system, more nuclei are formed even before spinodal. They merge into a larger nuclei with a smaller free energy penalty to form ramified shapes. We suggest order parameters to describe the extent of fluctuation, and their relation to the free energy profile.

  15. High-spin states in the 94Nb nucleus

    NASA Astrophysics Data System (ADS)

    Mărginean, N.; Bucurescu, D.; Căta-Danil, Ghe.; Căta-Danil, I.; Ivaşcu, M.; Ur, C. A.

    2000-09-01

    High-spin states have been studied for the first time in the 94Nb nucleus with the reaction 82Se(19F,α3nγ) at 68 MeV. A cascade of transitions has been observed, based on the (6)+ ground state and extending up to 6.5 MeV excitation and spin of about 19.

  16. Motility proteins and the origin of the nucleus.

    PubMed

    Dolan, Michael F; Melnitsky, Hannah; Margulis, Lynn; Kolnicki, Robin

    2002-11-01

    Hypotheses on the origin of eukaryotic cells must account for the origin of the microtubular cytoskeletal structures (including the mitotic spindle, undulipodium/cilium (so-called flagellum) and other structures underlain by the 9(2)+2 microtubular axoneme) in addition to the membrane-bounded nucleus. Whereas bacteria with membrane-bounded nucleoids have been described, no precedent for mitotic, cytoskeletal, or axonemal microtubular structures are known in prokaryotes. Molecular phylogenetic analyses indicate that the cells of the earliest-branching lineages of eukaryotes contain the karyomastigont cytoskeletal system. These protist cells divide via an extranuclear spindle and a persistent nuclear membrane. We suggest that this association between the centriole/kinetosome axoneme (undulipodium) and the nucleus existed from the earliest stage of eukaryotic cell evolution. We interpret the karyomastigont to be a legacy of the symbiosis between thermoacidophilic archaebacteria and motile eubacteria from which the first eukaryote evolved. Mutually inconsistent hypotheses for the origin of the nucleus are reviewed and sequenced proteins of cell motility are discussed because of their potential value in resolving this problem. A correlation of fossil evidence with modern cell and microbiological studies leads us to the karyomastigont theory of the origin of the nucleus.

  17. Calcium-regulated import of myosin IC into the nucleus.

    PubMed

    Maly, Ivan V; Hofmann, Wilma A

    2016-06-01

    Myosin IC is a molecular motor involved in intracellular transport, cell motility, and transcription. Its mechanical properties are regulated by calcium via calmodulin binding, and its functions in the nucleus depend on import from the cytoplasm. The import has recently been shown to be mediated by the nuclear localization signal located within the calmodulin-binding domain. In the present paper, it is demonstrated that mutations in the calmodulin-binding sequence shift the intracellular distribution of myosin IC to the nucleus. The redistribution is displayed by isoform B, described originally as the "nuclear myosin," but is particularly pronounced with isoform C, the normally cytoplasmic isoform. Furthermore, experimental elevation of the intracellular calcium concentration induces a rapid import of myosin into the nucleus. The import is blocked by the importin β inhibitor importazole. These findings are consistent with a mechanism whereby calmodulin binding prevents recognition of the nuclear localization sequence by importin β, and the steric inhibition of import is released by cell signaling leading to the intracellular calcium elevation. The results establish a mechanistic connection between the calcium regulation of the motor function of myosin IC in the cytoplasm and the induction of its import into the nucleus. © 2016 Wiley Periodicals, Inc.

  18. A continuing controversy: Has the cometary nucleus been resolved?

    NASA Technical Reports Server (NTRS)

    Sekanina, Z.

    1976-01-01

    Evidence is presented for classifying cometary nuclei into two basic types, described by core mantle and coreless models. Mass loss related nongravitational effects in a comet's motion as a function of time are included in considering gradual evaporation of an icy envelope surrounding the meteoric matrix in the core of the nucleus.

  19. Study of the variability of the nucleus of Centaurus A.

    NASA Astrophysics Data System (ADS)

    Fernandes de Mello Rabaca, D.; Abraham, Z.

    1990-11-01

    ABSTRACT. This work consists in the study of the variability of the nucleus of the peculiar galaxy NGC 5128 (Centaurus A) at the radio continuum frequency of 43 GHz. The data were obtained with the 13.7 m itapetinga Radiotelescope. The radio source presents a pair of inner radio lobes and a compact variable nucleus. The observational technique used was scans through the inner radio lobes and the nucleus. The quasi- simultaneous measurements of the flux density of each source allowed us to derive accurately the relative flux between them, and to obtain the real variability of the nucleus. RESUMO. Este trabalho consiste no estudo da variabilidade do nucleo da galaxia peculiar NGC 5128 (Centaurus A) no de radio na de 43 GHz. Os dados foram obtidos com 0 Radiotelescopio do Itapetinga. A radio fonte apresenta um par de lobulos internos e um nucleo compacto variavel. A tetnica observacional utilizada foi a de varreduras passando pelos lobulos e pelo nucleo. As medidas quase simultaneas da densidade de fluxo de cada fonte permitiu obter precisa- mente 0 fluxo relativo entre elas e a variabilidade real do nucleo. Keq woit : GALAXIES-RADIO

  20. CTP synthase forms cytoophidia in the cytoplasm and nucleus

    SciTech Connect

    Gou, Ke-Mian; Chang, Chia-Chun; Shen, Qing-Ji; Sung, Li-Ying; Liu, Ji-Long

    2014-04-15

    CTP synthase is an essential metabolic enzyme responsible for the de novo synthesis of CTP. Multiple studies have recently showed that CTP synthase protein molecules form filamentous structures termed cytoophidia or CTP synthase filaments in the cytoplasm of eukaryotic cells, as well as in bacteria. Here we report that CTP synthase can form cytoophidia not only in the cytoplasm, but also in the nucleus of eukaryotic cells. Both glutamine deprivation and glutamine analog treatment promote formation of cytoplasmic cytoophidia (C-cytoophidia) and nuclear cytoophidia (N-cytoophidia). N-cytoophidia are generally shorter and thinner than their cytoplasmic counterparts. In mammalian cells, both CTP synthase 1 and CTP synthase 2 can form cytoophidia. Using live imaging, we have observed that both C-cytoophidia and N-cytoophidia undergo multiple rounds of fusion upon glutamine analog treatment. Our study reveals the coexistence of cytoophidia in the cytoplasm and nucleus, therefore providing a good opportunity to investigate the intracellular compartmentation of CTP synthase. - Highlights: • CTP synthase forms cytoophidia not only in the cytoplasm but also in the nucleus. • Glutamine deprivation and Glutamine analogs promotes cytoophidium formation. • N-cytoophidia exhibit distinct morphology when compared to C-cytoophidia. • Both CTP synthase 1 and CTP synthase 2 form cytoophidia in mammalian cells. • Fusions of cytoophidia occur in the cytoplasm and nucleus.

  1. Antidromic activation of the isthmo-optic nucleus

    PubMed Central

    Holden, A. L.

    1968-01-01

    1. This paper describes experiments carried out to record from output cells in the isthmo-optic nucleus. 2. One-hundred and twenty-seven axonal responses were fired at fixed latency from the optic nerve-head. 3. Ninety-nine cell responses were fired trans-synaptically from the optic nerve-head. 4. Ninety-four cells were activated antidromically from the optic nerve-head. 5. Tectal tracks could be recognized by the field potential profile of the N-wave, R-wave and P-wave, and by the occurrence of fixed latency axonal responses and trans-synaptically fired cells. 6. Tectal tracks were verified histologically. 7. Tracks yielding antidromically activated cells were traced histologically to the isthmo-optic nucleus. 8. The antidromic A-wave could be recorded from the nucleus, corresponding in timing to the invasion of cell bodies. 9. Somatic records in the nucleus could be recognized by their duration, conformation, and A—B blocking. 10. When antidromic discharge was interacted with orthodromic firing, collision evidence could be provided, showing that the orthodromic impulse travels centrifugally to the retina. ImagesFig. 3Fig. 4 PMID:5675042

  2. Turn Up the Volume: Uncovering Nucleus Size Control Mechanisms.

    PubMed

    Good, Matthew C

    2015-06-08

    Reporting in Developmental Cell, Hara and Merten (2015) apply the use of microfabrication and in vitro analysis in cell-free extracts to the old problem of nuclear size control. The authors make insights into the regulation of nuclear growth that potentially explain the widely reported correlation between nucleus size and cell size.

  3. mRNA-Producing Pseudo-nucleus System.

    PubMed

    Shin, Seung Won; Park, Kyung Soo; Shin, Woo Jung; Um, Soong Ho

    2015-11-04

    A pseudo-eukaryotic nucleus (PEN) system consisting of a gene-containing DNA hydrogel encapsulated in a liposome is fabricated. Owing to the structural characteristics of gene-containing DNA hydrogel, mRNA transcription efficiency is promoted 2.57-fold. Through the use of PEN as a platform for mRNA delivery to the cytosol, prolonged protein translation is achieved.

  4. Synthesis of the Furan Nucleus Promoted by Ytterbium Triflate.

    PubMed

    Taddeo, Vito Alessandro; Genovese, Salvatore; Epifano, Francesco; Fiorito, Serena

    2015-11-01

    An efficient synthesis of differently substituted furans from acetylene dicarboxylates and β-dicarbonyl compounds is described. The furan nucleus was built by means of an Yb(OTf)3 catalyzed cycloaddition reaction yielding desired adducts in 91%-98% yield.

  5. A search for the production of direct leptons in nucleon-nucleus and nucleus-nucleus collisions

    SciTech Connect

    Kirk, P.N.

    1990-12-01

    This report discusses the following topics: subthreshold production experiment; testing and selection of PCOS amplifiers; transverse energy detector; development of a sensitive new amplifiers; single-lepton experiment. (LSP)

  6. Physical interrelation of volatile and refractories in a cometary nucleus

    NASA Astrophysics Data System (ADS)

    Fulle, Marco; Alice Team; Stern, Alan; CONSTERT Team; Kofman, Wlodek; COSIMA Team; Hilchenbach, Martin; GIADA Team; Rotundi, Alessandra; MIDAS Team; Bentley, Mark; MIRO Team; Hofstadter, Mark; OSIRIS Team; Sierks, Holger; ROSINA Team; Altwegg, Kathrin; RPC Team; Nilsson, Hans; Burch, James; Eriksson, Anders; Heinz-Glassmeier, Karl; Henri, Pierre; Carr, Christopher; RSI Team; Paetzold, Martin; , VIRTIS Team; Capaccioni, Fabrizio; Lander Team; Boehnhardt, Hermann; Bibring, Jean-Pierre; IDS Team; Gruen, Eberhard; Fulchignoni, Marcello; Weissman, Paul; Project Scientist Team; Taylor, Matt; Buratti, Bonnie; Altobelli, Nicolas; Choukroun, Mathieu; Ground-Based Observations Team; Snodgrass, Colin

    2016-10-01

    The Rosetta mission has been taking measurements of its target comet Comet 67P/Churyumov-Gerasimenko since early 2014 and will complete operations at the end of September 2016. The mission Science Management Plan, in 1994, laid out the the prime goals and themes of the mission. These five themes were: 1) To study the global characterisation of the Nuclues, the determination of the dynamics properties , surface morpholy and composition of the comet. 2) Examination of the Chemical, Mineralogical and isotopic compositions of volatiles and refractories in a cometary nucleus.3) Physical interrelation of volatile and refractories in a cometary nucleus4) Study the development of cometary activity and the process in the surface layer of the nucleus and in the inner coma5) The origins of comets, the relationship between cometary and interstellar material and the implications for the origin of the solar system,To cover all aspects of the Rosetta mission in this special Show case session, this abstracts is one of 5, with this particular presentation focusing on theme 3, in particular on a) The dust-to-gas ratio; b) distributed sources of volatiles; c) seasonal evolution of the dust size distribution.a) The dust-to-gas ratio has been provided by coma observations measuring the gas and dust loss rates from the nucleus surface. The ratio of these two loss rates provides a lower limit of the dust-to-gas ratio at the nucleus surface, since it does not take into account the largest chunks unable to leave the nucleus, or falling back due to the dominant gravity. We review the value inferred so far, its time evolution, and new techniques to directly measure it in the nucleus.b) Evidences offered by Rosetta observations of gas sublimating from dust particles are up to now faint. We report the few available observations and an estimate of the probable average water content in dust particles inferred by 3D gas-dynamical codes of 67P coma.c) The dust-size distribution tunes the sizes

  7. Structures and functions in the crowded nucleus: new biophysical insights

    NASA Astrophysics Data System (ADS)

    Hancock, Ronald

    2014-09-01

    Concepts and methods from the physical sciences have catalysed remarkable progress in understanding the cell nucleus in recent years. To share this excitement with physicists and encourage their interest in this field, this review offers an overview of how the physics which underlies structures and functions in the nucleus is becoming more clear thanks to methods which have been developed to simulate and study macromolecules, polymers, and colloids. The environment in the nucleus is very crowded with macromolecules, making entropic (depletion) forces major determinants of interactions. Simulation and experiments are consistent with their key role in forming membraneless compartments such as nucleoli, PML and Cajal bodies, and discrete "territories" for chromosomes. The chromosomes, giant linear polyelectrolyte polymers, exist in vivo in a state like a polymer melt. Looped conformations are predicted in crowded conditions, and have been confirmed experimentally and are central to the regulation of gene expression. Polymer theory has revealed how the chromosomes are so highly compacted in the nucleus, forming a "crumpled globule" with fractal properties which avoids knots and entanglements in DNA while allowing facile accessibility for its replication and transcription. Entropic repulsion between looped polymers can explain the confinement of each chromosome to a discrete region of the nucleus. Crowding and looping are predicted to facilitate finding the specific targets of factors which modulate activities of DNA. Simulation shows that entropic effects contribute to finding and repairing potentially lethal double-strand breaks in DNA by increasing the mobility of the broken ends, favouring their juxtaposition for repair. Signaling pathways are strongly influenced by crowding, which favours a processive mode of response (consecutive reactions without releasing substrates). This new information contributes to understanding the sometimes counter-intuitive consequences.

  8. Ultrastructural study of the nucleus Cuneiformis in the cat.

    PubMed

    Gioia, M; Bianchi, R

    1987-01-01

    The Cuneiformis nucleus (Cu.n.) is a reticular nucleus of the mesencephalic tegmentum which is involved in several functions and particularly in locomotor activities. While the physiological properties and the nervous connections of the nucleus have been studied, there is no data about its ultrastructure. Therefore, we investigated this region in cat at the electron microscope and with morphoquantitative methods to clarify its ultrastructural organization and particularly the characteristics of its synaptic complex. The neurons are small and medium in size, with a high nucleo-cytoplasmic ratio and a modest rough endoplasmic reticulum organization. The neuropil is very extensive. Myelinated axons are very numerous. Dendritic profiles whose plasmalemma is almost completely covered by synaptic boutons are observed frequently. There are few somatic synapses; 81% have symmetrical junctions and 23% have round vesicles only. There are numerous synapses in the neuropil, 40% having asymmetrical junctions and 60% containing round vesicles only. The greater functional complexity indicated by the morphological data and the greater extension of the neuropil synapses with respect to that of the somatic ones, suggest that the neuropil is the main site of modulation and integration of the inputs to the nucleus. A highly significant statistical difference between the sizes of the somatic vesicles and those of the neuropil was found. This may point to the presence of distinct populations of vesicles, which may be correlated with the variety of substances (neurotransmitters, neuropeptides etc ...) found in the nucleus. The remarkable ultrastructural similarity between the Cu.n. and the periaqueductal gray matter is discussed.

  9. Cytoskeletal tension induces the polarized architecture of the nucleus

    PubMed Central

    Kim, Dong-Hwee; Wirtz, Denis

    2016-01-01

    The nuclear lamina is a thin filamentous meshwork that provides mechanical support to the nucleus and regulates essential cellular processes such as DNA replication, chromatin organization, cell division, and differentiation. Isolated horizontal imaging using fluorescence and electron microscopy has long suggested that the nuclear lamina is composed of structurally different A-type and B-type lamin proteins and nuclear lamin-associated membrane proteins that together form a thin layer that is spatially isotropic with no apparent difference in molecular content or density between the top and bottom of the nucleus. Chromosomes are condensed differently along the radial direction from the periphery of the nucleus to the nuclear center; therefore, chromatin accessibility for gene expression is different along the nuclear radius. However, 3D confocal reconstruction reveals instead that major lamin protein lamin A/C forms an apically polarized Frisbee-like dome structure in the nucleus of adherent cells. Here we show that both A-type lamins and transcriptionally active chromatins are vertically polarized by the tension exercised by the perinuclear actin cap (or actin cap) that is composed of highly contractile actomyosin fibers organized at the apical surface of the nucleus. Mechanical coupling between actin cap and lamina through LINC (linkers of nucleoskeleton and cytoskeleton) protein complexes induces an apical distribution of transcription-active subnucleolar compartments and epigenetic markers of transcription-active genes. This study reveals that intranuclear structures, such as nuclear lamina and chromosomal architecture, are apically polarized through the extranuclear perinuclear actin cap in a wide range of somatic adherent cells. PMID:25701041

  10. Viral eukaryogenesis: was the ancestor of the nucleus a complex DNA virus?

    PubMed

    Bell, P J

    2001-09-01

    In the theory of viral eukaryogenesis I propose here, the eukaryotic nucleus evolved from a complex DNA virus. It is proposed that the virus established a persistent presence in the cytoplasm of a methanogenic mycoplasma and evolved into the eukaryotic nucleus by acquiring a set of essential genes from the host genome and eventually usurping its role. It is proposed that several characteristic features of the eukaryotic nucleus derive from its viral ancestry. These include mRNA capping, linear chromosomes, and separation of transcription from translation. In the model, phagocytosis and other membrane fusion-based processes are derived from viral membrane fusion processes and evolved in concert with the nucleus. The coevolution of phagocytosis and the nucleus rendered much of the host archaeal genome redundant since the protoeukaryote could obtain raw materials and energy by engulfing bacterial syntrophs/prey. This redundancy allowed loss of the archaeal chromosome, generating an organism with eukaryotic features. The evolution of phagocytosis allowed the eukaryotes to be the first organisms to occupy the niche of predator.

  11. Stefin B Interacts with Histones and Cathepsin L in the Nucleus*

    PubMed Central

    Čeru, Slavko; Konjar, Špela; Maher, Katarina; Repnik, Urška; Križaj, Igor; Benčina, Mojca; Renko, Miha; Nepveu, Alain; Žerovnik, Eva; Turk, Boris; Kopitar-Jerala, Nataša

    2010-01-01

    Stefin B (cystatin B) is an endogenous inhibitor of cysteine proteinases localized in the nucleus and the cytosol. Loss-of-function mutations in the stefin B gene (CSTB) gene were reported in patients with Unverricht-Lundborg disease (EPM1). We have identified an interaction between stefin B and nucleosomes, specifically with histones H2A.Z, H2B, and H3. In synchronized T98G cells, stefin B co-immunoprecipitated with histone H3, predominantly in the G1 phase of the cell cycle. Stefin B-deficient mouse embryonic fibroblasts entered S phase earlier than wild type mouse embryonic fibroblasts. In contrast, increased expression of stefin B in the nucleus delayed cell cycle progression in T98G cells. The delay in cell cycle progression was associated with the inhibition of cathepsin L in the nucleus, as judged from the decreased cleavage of the CUX1 transcription factor. In vitro, inhibition of cathepsin L by stefin B was potentiated in the presence of histones, whereas histones alone did not affect the cathepsin L activity. Interaction of stefin B with the Met-75 truncated form of cathepsin L in the nucleus was confirmed by fluorescence resonance energy transfer experiments in the living cells. Stefin B could thus play an important role in regulating the proteolytic activity of cathepsin L in the nucleus, protecting substrates such as transcription factors from its proteolytic processing. PMID:20075068

  12. Critical evaluation of the anatomical location of the Barrington nucleus: relevance for deep brain stimulation surgery of pedunculopontine tegmental nucleus.

    PubMed

    Blanco, Lisette; Yuste, Jose Enrique; Carrillo-de Sauvage, María Angeles; Gómez, Aurora; Fernández-Villalba, Emiliano; Avilés-Olmos, Itciar; Limousin, Patricia; Zrinzo, Ludvic; Herrero, María Trinidad

    2013-09-05

    Deep brain stimulation (DBS) has become the standard surgical procedure for advanced Parkinson's disease (PD). Recently, the pedunculopontine tegmental nucleus (PPN) has emerged as a potential target for DBS in patients whose quality of life is compromised by freezing of gait and falls. To date, only a few groups have published their long-term clinical experience with PPN stimulation. Bearing in mind that the Barrington (Bar) nucleus and some adjacent nuclei (also known as the micturition centre) are close to the PPN and may be affected by DBS, the aim of the present study was to review the anatomical location of this structure in human and other species. To this end, the Bar nucleus area was analysed in mouse, monkey and human tissues, paying particular attention to the anatomical position in humans, where it has been largely overlooked. Results confirm that anatomical location renders the Bar nucleus susceptible to influence by the PPN DBS lead or to diffusion of electrical current. This may have an undesirable impact on the quality of life of patients.

  13. How the nucleus and mitochondria communicate in energy production during stress: nuclear MtATP6, an early-stress responsive gene, regulates the mitochondrial F₁F₀-ATP synthase complex.

    PubMed

    Moghadam, Ali Asghar; Ebrahimie, Eemaeil; Taghavi, Seyed Mohsen; Niazi, Ali; Babgohari, Mahbobeh Zamani; Deihimi, Tahereh; Djavaheri, Mohammad; Ramezani, Amin

    2013-07-01

    A small number of stress-responsive genes, such as those of the mitochondrial F1F0-ATP synthase complex, are encoded by both the nucleus and mitochondria. The regulatory mechanism of these joint products is mysterious. The expression of 6-kDa subunit (MtATP6), a relatively uncharacterized nucleus-encoded subunit of F0 part, was measured during salinity stress in salt-tolerant and salt-sensitive cultivated wheat genotypes, as well as in the wild wheat genotypes, Triticum and Aegilops using qRT-PCR. The MtATP6 expression was suddenly induced 3 h after NaCl treatment in all genotypes, indicating an early inducible stress-responsive behavior. Promoter analysis showed that the MtATP6 promoter includes cis-acting elements such as ABRE, MYC, MYB, GTLs, and W-boxes, suggesting a role for this gene in abscisic acid-mediated signaling, energy metabolism, and stress response. It seems that 6-kDa subunit, as an early response gene and nuclear regulatory factor, translocates to mitochondria and completes the F1F0-ATP synthase complex to enhance ATP production and maintain ion homeostasis under stress conditions. These communications between nucleus and mitochondria are required for inducing mitochondrial responses to stress pathways. Dual targeting of 6-kDa subunit may comprise as a mean of inter-organelle communication and save energy for the cell. Interestingly, MtATP6 showed higher and longer expression in the salt-tolerant wheat and the wild genotypes compared to the salt-sensitive genotype. Apparently, salt-sensitive genotypes have lower ATP production efficiency and weaker energy management than wild genotypes; a stress tolerance mechanism that has not been transferred to cultivated genotypes.

  14. Extraction of structure functions for lepton-nucleus scattering in the quasi-elastic region

    NASA Astrophysics Data System (ADS)

    Kim, K. S.; Kim, Hungchong; Cheoun, Myung-Ki; So, W. Y.

    2016-12-01

    Within the framework of a relativistic single-particle model, we calculate inclusive electron-nucleus scattering by electromagnetic current, and neutrino-nucleus scattering by neutral and charged current in the quasi-elastic region. The longitudinal, the transverse, and the transverse-interference structure functions are extracted from the theoretical cross section by using the Rosenbluth separation method at fixed momentum transfer and scattering angle and then compared with each other from the viewpoint of these current interactions. The position of peak for the electron scattering shifts to higher energy transfer than that for the neutrino scattering. The axial and pseudoscalar terms turn out to play an important role in the neutrino-nucleus scattering.

  15. Characteristics of central collision events in Fe-nucleus interactions for 20 - 60 GeV/nucleon

    NASA Technical Reports Server (NTRS)

    Burnett, T. H.; Drake, S.; Derrickson, J. H.; Fountain, W.; Fuki, M.; Gregory, J. C.; Hayashi, T.; Hayashi, T.; Holynski, R.; Iwai, J.; Jones, W. V.

    1985-01-01

    A counter emulsion hybrid chamber in Japanese-American Cooperative Emulsion Experiment (JACEE-3) was flown on a balloon at the altitude (5.4 g/sq cm) in 1982 with the objective of probing the heavy nuclear collisions above 20 GeV per nucleon. In the energy region, it is suggested that nucleus-nucleus collisions provide dense collisions complex through compression and secondary particle production. In the lower energy region, an evidence of collective flow has been reported. And also, at higher energy region, it has been argued that nucleus has rather large stopping power. In this paper, the high multiplicity characteristics of Fe nucleus central collisions with energies 20 to 50 GeV/nucleon are presented. This is considered to be relevant to compressibility and collective flow of nuclear matter.

  16. Momentum Driving: Which Physical Processes Dominate Active Galactic Nucleus Feedback?

    NASA Astrophysics Data System (ADS)

    Ostriker, Jeremiah P.; Choi, Ena; Ciotti, Luca; Novak, Gregory S.; Proga, Daniel

    2010-10-01

    The deposition of mechanical feedback from a supermassive black hole (SMBH) in an active galactic nucleus into the surrounding galaxy occurs via broad-line winds which must carry mass and radial momentum as well as energy. The effect can be summarized by the dimensionless parameter η ={\\dot{M}_outf}/{\\dot{M}_acc}= {2 ɛ_wc^2}/{v_w^2} where epsilonw (≡ \\dot{E}_w/(\\dot{M}_accc^2)) is the efficiency with which accreted matter is turned into wind energy in the disk surrounding the central SMBH. The outflowing mass and momentum are proportional to η, and many prior treatments have essentially assumed that η = 0. We perform one- and two-dimensional simulations and find that the growth of the central SMBH is very sensitive to the inclusion of the mass and momentum driving but is insensitive to the assumed mechanical efficiency. For example in representative calculations, the omission of momentum and mass feedback leads to a hundred-fold increase in the mass of the SMBH to over 1010 M sun. When allowance is made for momentum driving, the final SMBH mass is much lower and the wind efficiencies that lead to the most observationally acceptable results are relatively low with epsilonw <~ 10-4.

  17. Responses of primate caudal parabrachial nucleus and Kolliker-fuse nucleus neurons to whole body rotation

    NASA Technical Reports Server (NTRS)

    Balaban, Carey D.; McGee, David M.; Zhou, Jianxun; Scudder, Charles A.

    2002-01-01

    The caudal aspect of the parabrachial (PBN) and Kolliker-Fuse (KF) nuclei receive vestibular nuclear and visceral afferent information and are connected reciprocally with the spinal cord, hypothalamus, amygdala, and limbic cortex. Hence, they may be important sites of vestibulo-visceral integration, particularly for the development of affective responses to gravitoinertial challenges. Extracellular recordings were made from caudal PBN cells in three alert, adult female Macaca nemestrina through an implanted chamber. Sinusoidal and position trapezoid angular whole body rotation was delivered in yaw, roll, pitch, and vertical semicircular canal planes. Sites were confirmed histologically. Units that responded during rotation were located in lateral and medial PBN and KF caudal to the trochlear nerve at sites that were confirmed anatomically to receive superior vestibular nucleus afferents. Responses to whole-body angular rotation were modeled as a sum of three signals: angular velocity, a leaky integration of angular velocity, and vertical position. All neurons displayed angular velocity and integrated angular velocity sensitivity, but only 60% of the neurons were position-sensitive. These responses to vertical rotation could display symmetric, asymmetric, or fully rectified cosinusoidal spatial tuning about a best orientation in different cells. The spatial properties of velocity and integrated velocity and position responses were independent for all position-sensitive neurons; the angular velocity and integrated angular velocity signals showed independent spatial tuning in the position-insensitive neurons. Individual units showed one of three different orientations of their excitatory axis of velocity rotation sensitivity: vertical-plane-only responses, positive elevation responses (vertical plane plus ipsilateral yaw), and negative elevation axis responses (vertical plane plus negative yaw). The interactions between the velocity and integrated velocity components

  18. Regional difference in sex steroid action on formation of morphological sex differences in the anteroventral periventricular nucleus and principal nucleus of the bed nucleus of the stria terminalis.

    PubMed

    Kanaya, Moeko; Tsuda, Mumeko C; Sagoshi, Shoko; Nagata, Kazuyo; Morimoto, Chihiro; Thu, Chaw Kyi Tha; Toda, Katsumi; Kato, Shigeaki; Ogawa, Sonoko; Tsukahara, Shinji

    2014-01-01

    Sex steroid action is critical to form sexually dimorphic nuclei, although it is not fully understood. We previously reported that masculinization of the principal nucleus of the bed nucleus of the stria terminalis (BNSTp), which is larger and has more neurons in males than in females, involves aromatized testosterone that acts via estrogen receptor-α (ERα), but not estrogen receptor-β (ERβ). Here, we examined sex steroid action on the formation of the anteroventral periventricular nucleus (AVPV) that is larger and has more neurons in females. Morphometrical analysis of transgenic mice lacking aromatase, ERα, or ERβ genes revealed that the volume and neuron number of the male AVPV were significantly increased by deletion of aromatase and ERα genes, but not the ERβ gene. We further examined the AVPV and BNSTp of androgen receptor knockout (ARKO) mice. The volume and neuron number of the male BNSTp were smaller in ARKO mice than those in wild-type mice, while no significant effect of ARKO was found on the AVPV and female BNSTp. We also examined aromatase, ERα, and AR mRNA levels in the AVPV and BNSTp of wild-type and ARKO mice on embryonic day (ED) 18 and postnatal day (PD) 4. AR mRNA in the BNSTp and AVPV of wild-type mice was not expressed on ED18 and emerged on PD4. In the AVPV, the aromatase mRNA level was higher on ED18, although the ERα mRNA level was higher on PD4 without any effect of AR gene deletion. Aromatase and ERα mRNA levels in the male BNSTp were significantly increased on PD4 by AR gene deletion. These results suggest that estradiol signaling via ERα during the perinatal period and testosterone signaling via AR during the postnatal period are required for masculinization of the BNSTp, whereas the former is sufficient to defeminize the AVPV.

  19. Regional Difference in Sex Steroid Action on Formation of Morphological Sex Differences in the Anteroventral Periventricular Nucleus and Principal Nucleus of the Bed Nucleus of the Stria Terminalis

    PubMed Central

    Kanaya, Moeko; Tsuda, Mumeko C.; Sagoshi, Shoko; Nagata, Kazuyo; Morimoto, Chihiro; Tha Thu, Chaw Kyi; Toda, Katsumi; Kato, Shigeaki; Ogawa, Sonoko; Tsukahara, Shinji

    2014-01-01

    Sex steroid action is critical to form sexually dimorphic nuclei, although it is not fully understood. We previously reported that masculinization of the principal nucleus of the bed nucleus of the stria terminalis (BNSTp), which is larger and has more neurons in males than in females, involves aromatized testosterone that acts via estrogen receptor-α (ERα), but not estrogen receptor-β (ERβ). Here, we examined sex steroid action on the formation of the anteroventral periventricular nucleus (AVPV) that is larger and has more neurons in females. Morphometrical analysis of transgenic mice lacking aromatase, ERα, or ERβ genes revealed that the volume and neuron number of the male AVPV were significantly increased by deletion of aromatase and ERα genes, but not the ERβ gene. We further examined the AVPV and BNSTp of androgen receptor knockout (ARKO) mice. The volume and neuron number of the male BNSTp were smaller in ARKO mice than those in wild-type mice, while no significant effect of ARKO was found on the AVPV and female BNSTp. We also examined aromatase, ERα, and AR mRNA levels in the AVPV and BNSTp of wild-type and ARKO mice on embryonic day (ED) 18 and postnatal day (PD) 4. AR mRNA in the BNSTp and AVPV of wild-type mice was not expressed on ED18 and emerged on PD4. In the AVPV, the aromatase mRNA level was higher on ED18, although the ERα mRNA level was higher on PD4 without any effect of AR gene deletion. Aromatase and ERα mRNA levels in the male BNSTp were significantly increased on PD4 by AR gene deletion. These results suggest that estradiol signaling via ERα during the perinatal period and testosterone signaling via AR during the postnatal period are required for masculinization of the BNSTp, whereas the former is sufficient to defeminize the AVPV. PMID:25398007

  20. Nucleus-nucleus collisions at very high energies

    SciTech Connect

    Hansen, O.

    1990-01-01

    The present report covers the material of two lectures. The first part, contains a collection of useful formulae from relativistic kinematics and deals with invariant cross sections and multiplicities. The remainder of the paper is on strangeness production in relativistic heavy ion collisions. Some elementary rules for particle production in nucleon-nucleon interactions are presented. This paper also contains arguments on why one expects enhanced strange particle production from the quark-gluon plasma. Next is presented some selected data on strangeness production in Si + Au and other interactions at 14.6 GeV/c per nucleon and from S + S at 200 GeV/c per nucleon. Some conclusions drawn from the experimental results are presented. 10 refs.

  1. Project Physics Handbook 6, The Nucleus.

    ERIC Educational Resources Information Center

    Harvard Univ., Cambridge, MA. Harvard Project Physics.

    Five experiments and nine activities are presented in this Unit 6 handbook. The experiments are related to random events, ranges of alpha and beta particles, half-lives, and radioactive tracers. The activities are concerned with the energy measurement in beta radiation, demonstration with sugar cubes, ionization by radioactivity, magnetic…

  2. The classical pion field in a nucleus

    NASA Astrophysics Data System (ADS)

    Ripka, Georges

    2008-12-01

    A self-consistent symmetry arises when the nucleon angular momentum j and the isospin t are coupled to a grand spin G. Closed G shells become sources of a classical pion field with a hedgehog shape. Although the amplitude of the pion field, as measured by the chiral angle, is small, it is found to perturb significantly the energies of the nucleon orbits.

  3. Scaling violation in hadron-nucleus interaction

    NASA Technical Reports Server (NTRS)

    Verbetski, Y. G.; Garsevanishvili, L. P.; Kotlyarevski, D. M.; Ladaria, N. K.; Tatalashvili, N. G.; Tsomaya, P. V.; Sherer, N. I.; Shabelski, Y. M.; Stemanetyan, G. Z.

    1985-01-01

    The scaling violation within the pionization region in the energy range of 0.2 to 2.0 TeV is shown on the basis of the analysis of angular characteristics in the interactions of the cosmic radiation hadrons with the nuclei of various substances (CH2, Al, Cu, Pb).

  4. Project Physics Reader 6, The Nucleus.

    ERIC Educational Resources Information Center

    Harvard Univ., Cambridge, MA. Harvard Project Physics.

    As a supplement to Project Physics Unit 6, a collection of articles is presented in this reader for student browsing. Five excerpts are concerned with the nuclear energy revolution, the 20th birthday and possible consequences of the atomic age, a scientist's view of science, and relations between mathematics and physics. Six book passages are…

  5. Development of injectable hydrogels for nucleus pulposus replacement

    NASA Astrophysics Data System (ADS)

    Thomas, Jonathan D.

    Intervertebral disc degeneration has been reported as the underlying cause for 75% of cases of lower back pain and is marked by dehydration of the nucleus pulposus within the intervertebral disc. There have been many implant designs to replace the nucleus pulposus. Some researchers have proposed the replacement of the nucleus pulposus with hydrogel materials. The insertion of devices made from these materials further compromises the annulus of the disc. An ideal nucleus replacement could be injected into the disc space and form a solid in vivo. However, injectable replacements using curing elastomers and thermoplastic materials are not ideal because of the potentially harmful exothermic heat evolved from their reactions and the toxicity of the reactants used. We propose a hydrogel system that can be injected as a liquid at 25°C and solidified to yield a hydrogel within the intervertebral disc at 37°C. In aqueous solutions, these polymers have Lower Critical Solution Temperatures (LCST) between 25-37°C, making them unique candidate materials for this application. Poly(N-isopropylacrylamide) (PNIPAAm) is the most widely studied LCST polymer due to its drastic transition near body temperature. However, by itself, pure PNIPAAm forms a hydrogel that has low water content and can readily undergo plastic deformation. To increase the water content and impart elasticity to PNIPAAm hydrogels, grafted and branched hydrogel systems were created that incorporated the thermogelling PNIPAAm and hydrophilic poly(ethylene glycol) (PEG). In this research, the effects of polymer composition and monomer to initiator ratio, which controls polymer MW, on the in vitro swelling properties (mass, chemical, and compressive mechanical stability) of hydrogels formed from aqueous solutions of these polymers were evaluated. Immersion studies were also conducted in solutions to simulate the osmotic environment of the nucleus pulposus. The effects of repeated compression and unloading cycles

  6. Physical meaning of the multiplicities of emitted nucleons in hadron-nucleus collisions

    NASA Technical Reports Server (NTRS)

    Strugalski, Z.

    1985-01-01

    The analysis of experimental data on hadron-nucleus collisions at energies from about 2 up to about 400 GeV was performed in order to discover a physical meaning of the multiplicity of emitted nucleons. Simple relations between the multiplicities and the thickness of the nuclear matter layer involved in collisions were obtained.

  7. Quasi-elastic neutrino-nucleus reactions

    NASA Astrophysics Data System (ADS)

    Valverde, M.; Nieves, J.; Amaro, J. E.

    2006-05-01

    The quasi-elastic contribution of the nuclear inclusive electron scattering model developed in [A. Gil, J. Nieves, and E. Oset: Nucl. Phys. A 627 (1997) 543] is extended to the study of electroweak charged current induced nuclear reactions at intermediate energies of interest for future neutrino oscillation experiments. The model accounts for long-range nuclear (RPA) correlations, final state interaction and Coulomb corrections. RPA correlations are shown to play a crucial role in the whole range of neutrino energies, up to 500 MeV, studied in this work. Predictions for inclusive muon capture for different nuclei, and for the reactions 12C(ν μ , μ -)X and 12C(ν e, e-)X near threshold are also given.

  8. The Nucleus of Translating as One Critical Concern in Translation Pedagogy and Assessment.

    ERIC Educational Resources Information Center

    Hu, Helen Chau

    1999-01-01

    Studies the translation of nonliterary texts. The objective is to associate the nucleus of translating with the value of a source-language text, advancing the claim that appropriately translating the nucleus is among the most important concerns, and to propose an approach to assessment for translation quality based on how the nucleus is rendered.…

  9. Actomyosin pulls to advance the nucleus in a migrating tissue cell.

    PubMed

    Wu, Jun; Kent, Ian A; Shekhar, Nandini; Chancellor, T J; Mendonca, Agnes; Dickinson, Richard B; Lele, Tanmay P

    2014-01-07

    The cytoskeletal forces involved in translocating the nucleus in a migrating tissue cell remain unresolved. Previous studies have variously implicated actomyosin-generated pushing or pulling forces on the nucleus, as well as pulling by nucleus-bound microtubule motors. We found that the nucleus in an isolated migrating cell can move forward without any trailing-edge detachment. When a new lamellipodium was triggered with photoactivation of Rac1, the nucleus moved toward the new lamellipodium. This forward motion required both nuclear-cytoskeletal linkages and myosin activity. Apical or basal actomyosin bundles were found not to translate with the nucleus. Although microtubules dampen fluctuations in nuclear position, they are not required for forward translocation of the nucleus during cell migration. Trailing-edge detachment and pulling with a microneedle produced motion and deformation of the nucleus suggestive of a mechanical coupling between the nucleus and the trailing edge. Significantly, decoupling the nucleus from the cytoskeleton with KASH overexpression greatly decreased the frequency of trailing-edge detachment. Collectively, these results explain how the nucleus is moved in a crawling fibroblast and raise the possibility that forces could be transmitted from the front to the back of the cell through the nucleus.

  10. Formation of a crystal nucleus from liquid

    PubMed Central

    Kawasaki, Takeshi; Tanaka, Hajime

    2010-01-01

    Crystallization is one of the most fundamental nonequilibrium phenomena universal to a variety of materials. It has so far been assumed that a supercooled liquid is in a “homogeneous disordered state” before crystallization. Contrary to this common belief, we reveal that a supercooled colloidal liquid is actually not homogeneous, but has transient medium-range structural order. We find that nucleation preferentially takes place in regions of high structural order via wetting effects, which reduce the crystal–liquid interfacial energy significantly and thus promotes crystal nucleation. This novel scenario provides a clue to solving a long-standing mystery concerning a large discrepancy between the rigorous numerical estimation of the nucleation rate on the basis of the classical nucleation theory and the experimentally observed ones. Our finding may shed light not only on the mechanism of crystal nucleation, but also on the fundamental nature of a supercooled liquid state. PMID:20663951

  11. Progressive activation of paratrigeminal nucleus during entrance to hibernation

    SciTech Connect

    Kilduff, T.S.; Sharp, F.R.; Heller, H.C. Univ. of California, San Francisco Veterans Administration Medical Center, San Francisco, CA )

    1988-07-01

    The paratrigeminal nucleus (Pa5) undergoes a progressive increase in its uptake of 2-({sup 14}C)deoxyglucose (2DG) relative to other brain structures during entrance to hibernation in the ground squirrel. This highly significant increase results in the Pa5 becoming the most highly labeled brain region during hibernation, even though it exhibits one of the lowest levels of 2DG uptake in the brain during the nonhibernating state. The progressive activation of the Pa5 observed during entrance is reversed during arousal from hibernation. These observations and the neuroanatomical projections of the Pa5 implicate this nucleus as playing a role in the entrance and maintenance of the hibernating state.

  12. Leading neutrons from polarized proton-nucleus collisions

    NASA Astrophysics Data System (ADS)

    Kopeliovich, B. Z.; Potashnikova, I. K.; Schmidt, Ivan

    2017-03-01

    Leading neutron production on protons is known to be subject to strong absorptive corrections, which have been under debate for a long time. On nuclear targets these corrections are significantly enhanced and push the partial cross sections of neutron production to the very periphery of the nucleus. As a result, the A-dependences of inclusive and diffractive neutron production turn out to be similar. The mechanism of π-a1 interference, which successfully explained the observed single-spin asymmetry of neutrons in polarized pp interactions, is extended here to polarized pA collisions. Corrected for nuclear effects it explains quite well the magnitude and sign of the asymmetry AN observed in inelastic events, resulting in a violent break up of the nucleus. However the excessive magnitude of AN observed in the diffractive sample, remains a challenge.

  13. Triple F - A Comet Nucleus Sample Return Mission

    NASA Technical Reports Server (NTRS)

    Kueppers, Michael; Keller, Horst Uwe; Kuhrt, Ekkehard; A'Hearn, Michael; Altwegg, Kathrin; Betrand, Regis; Busemann, Henner; Capria, Maria Teresa; Colangeli, Luigi

    2008-01-01

    The Triple F (Fresh From the Fridge) mission, a Comet Nucleus Sample Return, has been proposed to ESA s Cosmic Vision program. A sample return from a comet enables us to reach the ultimate goal of cometary research. Since comets are the least processed bodies in the solar system, the proposal goes far beyond cometary science topics (like the explanation of cometary activity) and delivers invaluable information about the formation of the solar system and the interstellar molecular cloud from which it formed. The proposed mission would extract three samples of the upper 50 cm from three locations on a cometary nucleus and return them cooled to Earth for analysis in the laboratory. The simple mission concept with a touch-and-go sampling by a single spacecraft was proposed as an M-class mission in collaboration with the Russian space agency ROSCOSMOS.

  14. Triple F - A Comet Nucleus Sample Return Mission

    NASA Technical Reports Server (NTRS)

    Kueppers, Michael; Keller, H. U.; Kuehrt, E.; A'Hearn, M. F.; Altwegg, K.; Bertrand, R.; Busemann, H.; Capria, M. T.; Colangeli, L.; Davidsson, B.; Ehrenfreund, P.; Knollenberg, J.; Mottola, S.; Weiss, P.; Zolensky, M.; Akim, E.; Basilevsky, A.; Galimov, E.; Gerasimov, M.; Korablev, O.; Charnley, S.; Nittler, L. R.; Sandford, S.; Weissman, P.

    2008-01-01

    The Triple F (Fresh From the Fridge) mission, a Comet Nucleus Sample Return, has been proposed to ESA's Cosmic Vision program. A sample return from a comet enables us to reach the ultimate goal of cometary research. Since comets are the least processed bodies in the solar system, the proposal goes far beyond cometary science topics (like the explanation of cometary activity) and delivers invaluable information about the formation of the solar system and the interstellar molecular cloud from which it formed. The proposed mission would extract three sample cores of the upper 50 cm from three locations on a cometary nucleus and return them cooled to Earth for analysis in the laboratory. The simple mission concept with a touch-andgo sampling by a single spacecraft was proposed as an M-class mission in collaboration with the Russian space agency ROSCOSMOS.

  15. Direct Observation of Nanoparticle-Cancer Cell Nucleus Interactions

    PubMed Central

    Dam, Duncan Hieu M.; Lee, Jung Heon; Sisco, Patrick N.; Co, Dick T.; Zhang, Ming; Wasielewski, Michael R.; Odom, Teri W.

    2012-01-01

    We report the direct visualization of interactions between drug-loaded nanoparticles and the cancer cell nucleus. Nanoconstructs composed of nucleolin-specific aptamers and gold nanostars were actively transported to the nucleus and induced major changes to the nuclear phenotype via nuclear envelope invaginations near the site of the construct. The number of local deformations could be increased by ultra-fast, light-triggered release of the aptamers from the surface of the gold nanostars. Cancer cells with more nuclear envelope folding showed increased caspase 3 and 7 activity (apoptosis) as well as decreased cell viability. This newly revealed correlation between drug-induced changes in nuclear phenotype and increased therapeutic efficacy could provide new insight for nuclear-targeted cancer therapy. PMID:22424173

  16. IC5063: A merger with a hidden luminous active nucleus

    NASA Technical Reports Server (NTRS)

    Colina, L.; Sparks, W. B.; Macchetto, F. D.

    1990-01-01

    IC5063 is a nearby galaxy classified as an SO and containing a system of dust lanes parallel to its major optical axis (Danziger, Goss and Wellington, 1981; Bergeron, Durret and Boksenberg, 1983). Extended emission line regions with high excitation properties have been detected over distances of up to 19 kpc from the nucleus. This galaxy has been classified as Seyfert 2 on the basis of its emission line spectrum. These characteristics make IC5063 one of the best candidates for a merger remnant and an excellent candidate for a hidden luminous active nucleus. Based on new broad and narrow band images and long-slit spectroscopy obtained at the ESO 3.6 m telescope, the authors present some preliminary results supporting this hypothesis.

  17. Volume regulation and shape bifurcation in the cell nucleus

    PubMed Central

    Kim, Dong-Hwee; Li, Bo; Si, Fangwei; Phillip, Jude M.; Wirtz, Denis; Sun, Sean X.

    2015-01-01

    ABSTRACT Alterations in nuclear morphology are closely associated with essential cell functions, such as cell motility and polarization, and correlate with a wide range of human diseases, including cancer, muscular dystrophy, dilated cardiomyopathy and progeria. However, the mechanics and forces that shape the nucleus are not well understood. Here, we demonstrate that when an adherent cell is detached from its substratum, the nucleus undergoes a large volumetric reduction accompanied by a morphological transition from an almost smooth to a heavily folded surface. We develop a mathematical model that systematically analyzes the evolution of nuclear shape and volume. The analysis suggests that the pressure difference across the nuclear envelope, which is influenced by changes in cell volume and regulated by microtubules and actin filaments, is a major factor determining nuclear morphology. Our results show that physical and chemical properties of the extracellular microenvironment directly influence nuclear morphology and suggest that there is a direct link between the environment and gene regulation. PMID:26243474

  18. Cell Autonomy and Synchrony of Suprachiasmatic Nucleus Circadian Oscillators

    PubMed Central

    Mohawk, Jennifer A.; Takahashi, Joseph S.

    2013-01-01

    The suprachiasmatic nucleus (SCN) of the hypothalamus is the site of the master circadian pacemaker in mammals. The individual cells of the SCN are capable of functioning independently from one another and therefore must form a cohesive circadian network through intercellular coupling. The network properties of the SCN lead to coordination of circadian rhythms among its neurons and neuronal subpopulations. There is increasing evidence for multiple interconnected oscillators within the SCN, and in this Review, we will highlight recent advances in our understanding of the complex organization and function of the cellular and network-level SCN clock. Understanding the way in which synchrony is achieved between cells in the SCN will provide insight into the means by which this important nucleus orchestrates circadian rhythms throughout the organism. PMID:21665298

  19. Towards a Deeper Understanding of the Nucleus with Exotic Nuclei

    NASA Astrophysics Data System (ADS)

    Ormand, Erich

    2006-10-01

    Despite more than fifty years of study, many questions about now nuclei are put together remain. While nuclei near the valley of stability have provided a wealth of information, they are not sufficient to provide us with a comprehensive and unified description of the nucleus. Especially lacking is an accurate picture of those exotic species that are the basis of cosmic alchemy. The missing pieces in the puzzle can be filled in with a determined experimental and theoretical effort focusing on nuclei lying far from the valley of stability. Here, I will outline the intellectual challenges that can be addressed by proposed exotic-beam facilities, and how new experimental data will quide and refine theoretical descriptions of the nucleus.

  20. Deformations and magnetic rotations in the Ni60 nucleus

    NASA Astrophysics Data System (ADS)

    Torres, D. A.; Cristancho, F.; Andersson, L.-L.; Johansson, E. K.; Rudolph, D.; Fahlander, C.; Ekman, J.; Du Rietz, R.; Andreoiu, C.; Carpenter, M. P.; Seweryniak, D.; Zhu, S.; Charity, R. J.; Chiara, C. J.; Hoel, C.; Pechenaya, O. L.; Reviol, W.; Sarantites, D. G.; Sobotka, L. G.; Baktash, C.; Yu, C.-H.; Carlsson, B. G.; Ragnarsson, I.

    2008-11-01

    Data from three experiments using the heavy-ion fusion evaporation-reaction 36Ar+28Si have been combined to study high-spin states in the residual nucleus Ni60, which is populated via the evaporation of four protons from the compound nucleus Ge64. The GAMMASPHERE array was used for all the experiments in conjunction with a 4π charged-particle detector arrays (MICROBALL, LUWUSIA) and neutron detectors (NEUTRON SHELL) to allow for the detection of γ rays in coincidence with the evaporated particles. An extended Ni60 level scheme is presented, comprising more than 270γ-ray transitions and 110 excited states. Their spins and parities have been assigned via directional correlations of γ rays emitted from oriented states. Spherical shell-model calculations in the fp-shell characterize some of the low-spin states, while the experimental results of the rotational bands are analyzed with configuration-dependent cranked Nilsson-Strutinsky calculations.

  1. The abnormal nucleus as a cause of congenital facial palsy

    PubMed Central

    Jemec, B.; Grobbelaar, A.; Harrison, D.

    2000-01-01

    BACKGROUND—Congenital facial palsy (CFP) is clinically defined as facial palsy present at birth. It is associated with considerable disfigurement and causes functional and emotional problems for the affected child. The aetiology of the majority of cases however, remains elusive.
AIMS—To investigate the role of a neuroanatomical abnormality as a cause of unilateral CFP.
METHODS—Magnetic resonance imaging (MRI) scans were performed on 21 patients with unilateral CFP. Fifteen patients had unilateral CFP only; six suffered from syndromes which can include unilateral CFP.
RESULTS—Of the 15 patients with unilateral CFP only, four (27%) had an abnormal nucleus or an abnormal weighting of this area on the MRI scan, compared to one (17%) of the remaining six patients.
CONCLUSION—Developmental abnormalities of the facial nucleus itself constitute an important, and previously ignored, cause of monosymptomatic unilateral CFP.

 PMID:10952650

  2. Control of cell nucleus shapes via micropillar patterns.

    PubMed

    Pan, Zhen; Yan, Ce; Peng, Rong; Zhao, Yingchun; He, Yao; Ding, Jiandong

    2012-02-01

    We herein report a material technique to control the shapes of cell nuclei by the design of the microtopography of substrates to which the cells adhere. Poly(D,L-lactide-co-glycolide) (PLGA) micropillars or micropits of a series of height or depth were fabricated, and some surprising self deformation of the nuclei of bone marrow stromal cells (BMSCs) was found in the case of micropillars with a sufficient height. Despite severe nucleus deformation, BMSCs kept the ability of proliferation and differentiation. We further demonstrated that the shapes of cell nuclei could be regulated by the appropriate micropillar patterns. Besides circular and elliptoid shapes, some unusual nucleus shapes of BMSCs have been achieved, such as square, cross, dumbbell, and asymmetric sphere-protrusion.

  3. Direct observation of nanoparticle-cancer cell nucleus interactions.

    PubMed

    Dam, Duncan Hieu M; Lee, Jung Heon; Sisco, Patrick N; Co, Dick T; Zhang, Ming; Wasielewski, Michael R; Odom, Teri W

    2012-04-24

    We report the direct visualization of interactions between drug-loaded nanoparticles and the cancer cell nucleus. Nanoconstructs composed of nucleolin-specific aptamers and gold nanostars were actively transported to the nucleus and induced major changes to the nuclear phenotype via nuclear envelope invaginations near the site of the construct. The number of local deformations could be increased by ultrafast, light-triggered release of the aptamers from the surface of the gold nanostars. Cancer cells with more nuclear envelope folding showed increased caspase 3 and 7 activity (apoptosis) as well as decreased cell viability. This newly revealed correlation between drug-induced changes in nuclear phenotype and increased therapeutic efficacy could provide new insight for nuclear-targeted cancer therapy.

  4. Volume regulation and shape bifurcation in the cell nucleus.

    PubMed

    Kim, Dong-Hwee; Li, Bo; Si, Fangwei; Phillip, Jude M; Wirtz, Denis; Sun, Sean X

    2015-09-15

    Alterations in nuclear morphology are closely associated with essential cell functions, such as cell motility and polarization, and correlate with a wide range of human diseases, including cancer, muscular dystrophy, dilated cardiomyopathy and progeria. However, the mechanics and forces that shape the nucleus are not well understood. Here, we demonstrate that when an adherent cell is detached from its substratum, the nucleus undergoes a large volumetric reduction accompanied by a morphological transition from an almost smooth to a heavily folded surface. We develop a mathematical model that systematically analyzes the evolution of nuclear shape and volume. The analysis suggests that the pressure difference across the nuclear envelope, which is influenced by changes in cell volume and regulated by microtubules and actin filaments, is a major factor determining nuclear morphology. Our results show that physical and chemical properties of the extracellular microenvironment directly influence nuclear morphology and suggest that there is a direct link between the environment and gene regulation.

  5. Electromagnetic properties of the Beryllium-11 nucleus in Halo EFT

    NASA Astrophysics Data System (ADS)

    Phillips, D. R.; Hammer, H.-W.

    2010-04-01

    We compute electromagnetic properties of the Beryllium-11 nucleus using an effective field theory that exploits the separation of scales in this halo system. We fix the parameters of the EFT from measured data on levels and scattering lengths in the 10Be plus neutron system. We then obtain predictions for the B(E1) strength of the 1/2+ to 1/2- transition in the 11Be nucleus. We also compute the charge radius of the ground state of 11Be. Agreement with experiment within the expected accuracy of a leading-order computation in this EFT is obtained. We also indicate how higher-order corrections that affect both s-wave and p-wave 10 Be-neutron interactions will affect our results.

  6. The cellular mastermind(?) – Mechanotransduction and the nucleus

    PubMed Central

    Kaminski, Ashley; Fedorchak, Gregory R.; Lammerding, Jan

    2015-01-01

    Cells respond to mechanical stimulation by activation of specific signaling pathways and genes that allow the cell to adapt to its dynamic physical environment. How cells sense the various mechanical inputs and translate them into biochemical signals remains an area of active investigation. Recent reports suggest that the cell nucleus may be directly implicated in this cellular mechanotransduction process. In this chapter, we discuss how forces applied to the cell surface and cytoplasm induce changes in nuclear structure and organization, which could directly affect gene expression, while also highlighting the complex interplay between nuclear structural proteins and transcriptional regulators that may further modulate mechanotransduction signaling. Taken together, these findings paint a picture of the nucleus as a central hub in cellular mechanotransduction—both structurally and biochemically—with important implications in physiology and disease. PMID:25081618

  7. Exporting RNA from the nucleus to the cytoplasm.

    PubMed

    Köhler, Alwin; Hurt, Ed

    2007-10-01

    The transport of RNA molecules from the nucleus to the cytoplasm is fundamental for gene expression. The different RNA species that are produced in the nucleus are exported through the nuclear pore complexes via mobile export receptors. Small RNAs (such as tRNAs and microRNAs) follow relatively simple export routes by binding directly to export receptors. Large RNAs (such as ribosomal RNAs and mRNAs) assemble into complicated ribonucleoprotein (RNP) particles and recruit their exporters via class-specific adaptor proteins. Export of mRNAs is unique as it is extensively coupled to transcription (in yeast) and splicing (in metazoa). Understanding the mechanisms that connect RNP formation with export is a major challenge in the field.

  8. Soluble spiroperidol binding factors from bovine caudate nucleus.

    PubMed

    Winkler, M H; Berl, S

    1982-09-01

    Several properties of soluble spiroperidol binding factors separated from bovine caudate nucleus have been investigated by a previously unreported procedure. Data consistent with high particle weight and rapid binding equilibration are reported for high-affinity (+)butaclamol-sensitive components of a digitonin extract. A slower sedimenting component is found that also exhibits high affinity for spiroperidol but is not sensitive to (+)butaclamol. Centrifugation of a caudate nucleus homogenate yields a supernatant that appears to contain a component that exhibits spiroperidol binding that is more sensitive to displacement by (-) than by (+)butaclamol. The procedure used effects rapid separation of bound from unbound tritiated ligand on short columns of Sephadex G-15 followed by extrusion and sectioning of the Sephadex. The radioactivity remaining with each section is determined. The procedure is very rapid; the addition of active phases or the changing of the ionic environment, which may disturb the equilibrium, is avoided; and recovery of the protein free of bound ligand is easily affected.

  9. Dynamics of Galectin-3 in the Nucleus and Cytoplasm

    PubMed Central

    Haudek, Kevin C.; Spronk, Kimberly J.; Voss, Patricia G.; Patterson, Ronald J.; Wang, John L.; Arnoys, Eric J.

    2009-01-01

    This review summarizes selected studies on galectin-3 (Gal3) as an example of the dynamic behavior of a carbohydrate-binding protein in the cytoplasm and nucleus of cells. Within the 15-member galectin family of proteins, Gal3 (Mr ~30,000) is the sole representative of the chimera subclass in which a proline- and glycine-rich NH2-terminal domain is fused onto a COOH-terminal carbohydrate recognition domain responsible for binding galactose-containing glycoconjugates. The protein shuttles between the cytoplasm and nucleus on the basis of targeting signals that are recognized by importin(s) for nuclear localization and exportin-1 (CRM1) for nuclear export. Depending on the cell type, specific experimental conditions in vitro, or tissue location, Gal3 has been reported to be exclusively cytoplasmic, predominantly nuclear, or distributed between the two compartments. The nuclear versus cytoplasmic distribution of the protein must reflect, then, some balance between nuclear import and export, as well as mechanisms of cytoplasmic anchorage or binding to a nuclear component. Indeed, a number of ligands have been reported for Gal3 in the cytoplasm and in the nucleus. Most of the ligands appear to bind Gal3, however, through protein-protein interactions rather than through protein-carbohydrate recognition. In the cytoplasm, for example, Gal3 interacts with the apoptosis repressor Bcl-2 and this interaction may be involved in Gal3’s anti-apoptotic activity. In the nucleus, Gal3 is a required pre-mRNA splicing factor; the protein is incorporated into spliceosomes via its association with the U1 small nuclear ribonucleoprotein (snRNP) complex. Although the majority of these interactions occur via the carbohydrate recognition domain of Gal3 and saccharide ligands such as lactose can perturb some of these interactions, the significance of the protein’s carbohydrate-binding activity, per se, remains a challenge for future investigations. PMID:19616076

  10. Decay of the N =126 , 213Fr nucleus

    NASA Astrophysics Data System (ADS)

    Pragati, Deo, A. Y.; Podolyák, Zs.; Walker, P. M.; Algora, A.; Rubio, B.; Agramunt, J.; Fraile, L. M.; Al-Dahan, N.; Alkhomashi, N.; Briz, J. A.; Aguado, M. E. Estevez; Farrelly, G.; Gelletly, W.; Herlert, A.; Köster, U.; Maira, A.

    2016-12-01

    γ rays following the EC/β+ and α decay of the N = 126, 213Fr nucleus have been observed at the CERN isotope separator on-line (ISOLDE) facility with the help of γ -ray and conversion-electron spectroscopy. These γ rays establish several hitherto unknown excited states in 213Rn. Also, five new α -decay branches from the 213Fr ground state have been discovered. Shell model calculations have been performed to understand the newly observed states in 213Rn.

  11. K--Nucleus Potentials Consistent with Kaonic Atoms

    NASA Astrophysics Data System (ADS)

    Cieply, A.; Friedman, E.; Gal, A.; Mares, J.

    2004-03-01

    Various models of the K- nucleus potential have been compared and tested in fits to kaonic atom data. The calculations give basically two vastly different predictions for the depth of the K- optical potential at the nuclear density. The study of the (K-stop, π ) reaction could help to distinguish between K- optical potentials as the Λ -hypernuclear formation rates are sensitive to the details of the initial-state K- wave function.

  12. Ion channels at the nucleus: electrophysiology meets the genome.

    PubMed

    Matzke, Antonius J M; Weiger, Thomas M; Matzke, Marjori

    2010-07-01

    The nuclear envelope is increasingly viewed from an electrophysiological perspective by researchers interested in signal transduction pathways that influence gene transcription and other processes in the nucleus. Here, we describe evidence for ion channels and transporters in the nuclear membranes and for possible ion gating by the nuclear pores. We argue that a systems-level understanding of cellular regulation is likely to require the assimilation of nuclear electrophysiology into molecular and biochemical signaling pathways.

  13. Nucleus incertus inactivation impairs spatial learning and memory in rats.

    PubMed

    Nategh, Mohsen; Nikseresht, Sara; Khodagholi, Fariba; Motamedi, Fereshteh

    2015-02-01

    Nucleus incertus (NI) is a pontine nucleus which releases mainly GABA and relaxin-3 in rats. Its suggested functions include response to stress, arousal, and modulation of hippocampal theta rhythm. Since the role of NI in learning and memory has not been well characterized, therefore the involvement of this nucleus in spatial learning and memory and the aftermath hippocampal levels of c-fos and pCREB were evaluated. NI was targeted by implanting cannula in male rats. For reference memory, NI was inactivated by lidocaine (0.4 μl, 4%) at three stages of acquisition, consolidation and retrieval in Morris water maze paradigm. For working memory, NI was inactivated in acquisition and retrieval phases. Injection of lidocaine prior to the first training session of reference memory significantly increased the distance moved, suggesting that inactivation of NI delays acquisition in this spatial task. Inactivation also interfered with the retrieval phase of spatial reference memory, as the time in target quadrant for lidocaine group was less, and the escape latency was higher compared to the control group. However, no difference was observed in the consolidation phase. In the working memory task, with inter-trial intervals of 75 min, the escape latency was higher when NI was inactivated in the retrieval phase. In addition, c-fos and pCREB/CREB levels decreased in NI-inhibited rats. This study suggests that nucleus incertus might participate in acquisition of spatial reference, and retrieval of both spatial reference and working memory. Further studies should investigate possible roles of NI in the hippocampal plasticity.

  14. Study of Comet Nucleus Gamma-Ray Spectrometer Penetration System

    NASA Technical Reports Server (NTRS)

    Adams, G. L.; Amundsen, R. J.; Beardsley, R. W.; Cash, R. H.; Clark, B. C.; Knight, T. C. D.; Martin, J. P.; Monti, P.; Outteridge, D. A.; Plaster, W. D.

    1986-01-01

    A penetrator system has been suggested as an approach for making in situ measurements of the composition and physical properties of the nucleus of a comet. This study has examined in detail the feasibility of implementing the penetrator concept. The penetrator system and mission designs have been developed and iterated in sufficient detail to provide a high level of confidence that the concept can be implemented within the constraints of the Mariner Mark 2 spacecraft.

  15. Analysis about the force of electrons revolve around the nucleus

    NASA Astrophysics Data System (ADS)

    Yongquan, Han

    1, Let's compare the difference of two algorithms: the electrostatic force between protons and electrons, F1 = ke2 / r2, r is the radius of the electron around the nucleus movement - within 10-10 meters; Electronic movement speed is close to the light- about 107 meters per second, the size of the centripetal force F2 = v2m/r. F1 should be approximately equal to F2,calculate the ratio of F1 and F2, F2 / F1 = (v2m/r) (ke2 / r2) / = (107 * 107 * 0.91 * 10-30 / r)/(9 * 109 * 1.6* 10-19*1.6*10-19 / r2) = 4 x 103.The calculation shows that not only the electrostatic force and other force. 2, The radius of the electron orbiting around the nucleus named r, F = Ke2 / r2 = 9 x 109 x #¨1.6 x 10 -19) 2 / r2 = v2m/r, r = 2.5 x 10-14 meters, namely that the radius of hydrogen atom is about 2.5 x 10- 14 meters, that is different with the observed result (10-10 meters).Electrons revolve around the nucleus may faster than 107 m/s, can almost reach 108 meters per second, if the electronic moves by 108 meters per second, hydrogen atom radius is approximately 2. 5 x 10 -16 meters, has converged in the interior of the nucleus, it is not possible. Use density to instead of electricity, can solve this problem. Author: hanyongquan TEL: 15611860790

  16. Theory and phenomenology of coherent neutrino-nucleus scattering

    SciTech Connect

    McLaughlin, Gail

    2015-07-15

    We review the theory and phenomenology of coherent elastic neutrino-nucleus scattering (CEνNS). After a brief introduction, we summarize the places where CEνNS is already in use and then turn to future physics opportunities from CEνNS. CEνNS has been proposed as a way to limit or discover beyond the standard model physics, measure the nuclear-neutron radius and constrain the Weinberg angle.

  17. Methods and compositions for targeting macromolecules into the nucleus

    SciTech Connect

    Chook, Yuh Min

    2013-06-25

    The present invention includes compositions, methods and kits for directing an agent across the nuclear membrane of a cell. The present invention includes a Karyopherin beta2 translocation motif in a polypeptide having a slightly positively charged region or a slightly hydrophobic region and one or more R/K/H-X.sub.(2-5)-P-Y motifs. The polypeptide targets the agent into the cell nucleus.

  18. Emission of charged particles from excited compound nucleus

    SciTech Connect

    Kalandarov, Sh. A.; Adamian, G. G.; Antonenko, N. V.

    2010-11-24

    The formation and decay of excited compound nucleus are studied within the dinuclear system model[1]. The cross sections of complex fragment emission are calculated and compared with experimental data for the reactions {sup 3}He+{sup 108}Ag, {sup 78,82}Kr+{sup 12}C. Angular momentum dependence of cluster emission in {sup 78}Kr+{sup 12}C and {sup 40}Ca+{sup 78}Kr reactions is demonstrated.

  19. D¯ D meson pair production in antiproton-nucleus collisions

    NASA Astrophysics Data System (ADS)

    Shyam, R.; Tsushima, K.

    2016-10-01

    We study the D ¯D (D¯0D0 and D-D+) charm meson pair production in antiproton (p ¯) induced reactions on nuclei at beam energies ranging from threshold to several GeV. Our model is based on an effective Lagrangian approach that has only the baryon-meson degrees of freedom and involves the physical hadron masses. The reaction proceeds via the t -channel exchanges of Λc+, Σc+, and Σc++ baryons in the initial collision of the antiproton with one of the protons of the target nucleus. The medium effects on the exchanged baryons are included by incorporating in the corresponding propagators, the effective charm baryon masses calculated within a quark-meson coupling (QMC) model. The wave functions of the bound proton have been determined within the QMC model as well as in a phenomenological model where they are obtained by solving the Dirac equation with appropriate scalar and vector potentials. The initial- and final-state distortion effects have been approximated by using an eikonal approximation-based procedure. Detailed numerical results are presented for total and double differential cross sections for the D¯0D0 and D-D+ production reactions on 16O and 90Zr targets. It is noted that at p ¯ beam momenta of interest to the P ¯ ANDA experiment, medium effects lead to noticeable enhancements in the charm meson production cross sections.

  20. Ab initio description of the exotic unbound 7He nucleus

    DOE PAGES

    Baroni, Simone; Navratil, Petr; Quaglioni, Sofia

    2013-01-11

    In this study, the neutron-rich unbound 7He nucleus has been the subject of many experimental investigations. While the ground-state 3/2– resonance is well established, there is a controversy concerning the excited 1/2– resonance reported in some experiments as low lying and narrow (ER~1 MeV, Γ≤1 MeV) while in others as very broad and located at a higher energy. This issue cannot be addressed by ab initio theoretical calculations based on traditional bound-state methods. We introduce a new unified approach to nuclear bound and continuum states based on the coupling of the no-core shell model, a bound-state technique, with the no-coremore » shell model combined with the resonating-group method, a nuclear scattering technique. Our calculations describe the ground-state resonance in agreement with experiment and, at the same time, predict a broad 1/2– resonance above 2 MeV.« less

  1. Developmental Changes in Synaptic Distribution in Arcuate Nucleus Neurons

    PubMed Central

    Kirigiti, Melissa A.; Baquero, Karalee C.; Lee, Shin J.; Smith, M. Susan; Grove, Kevin L.

    2015-01-01

    Neurons coexpressing neuropeptide Y, agouti-related peptide, and GABA (NAG) play an important role in ingestive behavior and are located in the arcuate nucleus of the hypothalamus. NAG neurons receive both GABAergic and glutamatergic synaptic inputs, however, the developmental time course of synaptic input organization of NAG neurons in mice is unknown. In this study, we show that these neurons have low numbers of GABAergic synapses and that GABA is inhibitory to NAG neurons during early postnatal period. In contrast, glutamatergic inputs onto NAG neurons are relatively abundant by P13 and are comparatively similar to the levels observed in the adult. As mice reach adulthood (9–10 weeks), GABAergic tone onto NAG neurons increases. At this age, NAG neurons received similar numbers of inhibitory and EPSCs. To further differentiate age-associated changes in synaptic distribution, 17- to 18-week-old lean and diet-induced obesity (DIO) mice were studied. Surprisingly, NAG neurons from lean adult mice exhibit a reduction in the GABAergic synapses compared with younger adults. Conversely, DIO mice display reductions in the number of GABAergic and glutamatergic inputs onto NAG neurons. Based on these experiments, we propose that synaptic distribution in NAG neurons is continuously restructuring throughout development to accommodate the animals' energy requirements. PMID:26041922

  2. Nucleus caudalis lesioning: Case report of chronic traumatic headache relief

    PubMed Central

    Sandwell, Stephen E.; El-Naggar, Amr O.

    2011-01-01

    Background: The nucleus caudalis dorsal root entry zone (DREZ) surgery is used to treat intractable central craniofacial pain. This is the first journal publication of DREZ lesioning used for the long-term relief of an intractable chronic traumatic headache. Case Description: A 40-year-old female experienced new-onset bi-temporal headaches following a traumatic head injury. Despite medical treatment, her pain was severe on over 20 days per month, 3 years after the injury. The patient underwent trigeminal nucleus caudalis DREZ lesioning. Bilateral single-row lesions were made at 1-mm interval between the level of the obex and the C2 dorsal nerve roots, using angled radiofrequency electrodes, brought to 80°C for 15 seconds each, along a path 1 to 1.2 mm posterior to the accessory nerve rootlets. The headache improved, but gradually returned. Five years later, her headaches were severe on over 24 days per month. The DREZ surgery was then repeated. Her headaches improved and the relief has continued for 5 additional years. She has remained functional, with no limitation in instrumental activities of daily living. Conclusions: The nucleus caudalis DREZ surgery brought long-term relief to a patient suffering from chronic traumatic headache. PMID:22059123

  3. Presynaptic and extrasynaptic regulation of posterior nucleus of thalamus.

    PubMed

    Park, Anthony; Li, Ying; Masri, Radi; Keller, Asaf

    2017-03-22

    The posterior nucleus of thalamus (PO) is a higher-order nucleus involved in sensorimotor processing, including nociception. An important characteristic of PO is its wide range of activity profiles that vary across states of arousal, thought to underlie differences in somatosensory perception subject to attention and degree of consciousness. Further, PO loses the ability to down-regulate its activity level in some forms of chronic pain, suggesting that regulatory mechanisms underlying the normal modulation of PO activity may be pathologically altered. Yet, the mechanisms responsible for regulating such a wide dynamic range of activity are unknown. Here, we test a series of hypotheses regarding the function of several presynaptic receptors on both GABAergic and glutamatergic afferents targeting PO in mouse, using acute slice electrophysiology. We found that presynaptic GABAB receptors are present on both GABAergic and glutamatergic terminals in PO, but only those on GABAergic terminals are tonically active. We also found that release from GABAergic terminals, but not glutamatergic terminals, is suppressed by cholinergic activation, and that a subpopulation of GABAergic terminals is regulated by cannabinoids. Finally, we discovered the presence of tonic currents mediated by extrasynaptic GABAA receptors in PO that are heterogeneously distributed across the nucleus. Thus, we demonstrate that multiple regulatory mechanisms concurrently exist in PO, and we propose that regulation of inhibition, rather than excitation, is the more consequential mechanism by which PO activity can be regulated.

  4. Relief memory consolidation requires protein synthesis within the nucleus accumbens.

    PubMed

    Bruning, Johann E A; Breitfeld, Tino; Kahl, Evelyn; Bergado-Acosta, Jorge R; Fendt, Markus

    2016-06-01

    Relief learning refers to the association of a stimulus with the relief from an aversive event. The thus-learned relief stimulus then can induce, e.g., an attenuation of the startle response or approach behavior, indicating positive valence. Previous studies revealed that the nucleus accumbens is essential for the acquisition and retrieval of relief memory. Here, we ask whether the nucleus accumbens is also the brain site for consolidation of relief memory into a long-term form. In rats, we blocked local protein synthesis within the nucleus accumbens by local infusions of anisomycin at different time points during a relief conditioning experiment. Accumbal anisomycin injections immediately after the relief conditioning session, but not 4 h later, prevented the consolidation into long-term relief memory. The retention of already consolidated relief memory was not affected by anisomycin injections. This identifies a time window and site for relief memory consolidation. These findings should complement our understanding of the full range of effects of adverse experiences, including cases of their distortion in humans such as post-traumatic stress disorder and/or phobias.

  5. Nucleus- and cell-specific gene expression in monkey thalamus.

    PubMed

    Murray, Karl D; Choudary, Prabhakara V; Jones, Edward G

    2007-02-06

    Nuclei of the mammalian thalamus are aggregations of neurons with unique architectures and input-output connections, yet the molecular determinants of their organizational specificity remain unknown. By comparing expression profiles of thalamus and cerebral cortex in adult rhesus monkeys, we identified transcripts that are unique to dorsal thalamus or to individual nuclei within it. Real-time quantitative PCR and in situ hybridization analyses confirmed the findings. Expression profiling of individual nuclei microdissected from the dorsal thalamus revealed additional subsets of nucleus-specific genes. Functional annotation using Gene Ontology (GO) vocabulary and Ingenuity Pathways Analysis revealed overrepresentation of GO categories related to development, morphogenesis, cell-cell interactions, and extracellular matrix within the thalamus- and nucleus-specific genes, many involved in the Wnt signaling pathway. Examples included the transcription factor TCF7L2, localized exclusively to excitatory neurons; a calmodulin-binding protein PCP4; the bone extracellular matrix molecules SPP1 and SPARC; and other genes involved in axon outgrowth and cell matrix interactions. Other nucleus-specific genes such as CBLN1 are involved in synaptogenesis. The genes identified likely underlie nuclear specification, cell phenotype, and connectivity during development and their maintenance in the adult thalamus.

  6. AN OFF-CENTERED ACTIVE GALACTIC NUCLEUS IN NGC 3115

    SciTech Connect

    Menezes, R. B.; Steiner, J. E.; Ricci, T. V.

    2014-11-20

    NGC 3115 is an S0 galaxy that has always been considered to have a pure absorption-line spectrum. Some recent studies have detected a compact radio-emitting nucleus in this object, coinciding with the photometric center and with a candidate for the X-ray nucleus. This is evidence of the existence of a low-luminosity active galactic nucleus (AGN) in the galaxy, although no emission line has ever been observed. We report the detection of an emission-line spectrum of a type 1 AGN in NGC 3115, with an Hα luminosity of L {sub Hα} = (4.2 ± 0.4) × 10{sup 37} erg s{sup –1}. Our analysis revealed that this AGN is located at a projected distance of ∼0.''29 ± 0.''05 (corresponding to ∼14.3 ± 2.5 pc) from the stellar bulge center, which is coincident with the kinematic center of this object's stellar velocity map. The black hole corresponding to the observed off-centered AGN may form a binary system with a black hole located at the stellar bulge center. However, it is also possible that the displaced black hole is the merged remnant of the binary system coalescence, after the ''kick'' caused by the asymmetric emission of gravitational waves. We propose that certain features in the stellar velocity dispersion map are the result of perturbations caused by the off-centered AGN.

  7. By moonlighting in the nucleus, villin regulates epithelial plasticity

    PubMed Central

    Patnaik, Srinivas; George, Sudeep P.; Pham, Eric; Roy, Swati; Singh, Kanchan; Mariadason, John M.; Khurana, Seema

    2016-01-01

    Villin is a tissue-specific, actin-binding protein involved in the assembly and maintenance of microvilli in polarized epithelial cells. Conversely, villin is also linked with the loss of epithelial polarity and gain of the mesenchymal phenotype in migrating, invasive cells. In this study, we describe for the first time how villin can switch between these disparate functions to change tissue architecture by moonlighting in the nucleus. Our study reveals that the moonlighting function of villin in the nucleus may play an important role in tissue homeostasis and disease. Villin accumulates in the nucleus during wound repair, and altering the cellular microenvironment by inducing hypoxia increases the nuclear accumulation of villin. Nuclear villin is also associated with mouse models of tumorigenesis, and a systematic analysis of a large cohort of colorectal cancer specimens confirmed the nuclear distribution of villin in a subset of tumors. Our study demonstrates that nuclear villin regulates epithelial–mesenchymal transition (EMT). Altering the nuclear localization of villin affects the expression and activity of Slug, a key transcriptional regulator of EMT. In addition, we find that villin directly interacts with a transcriptional corepressor and ligand of the Slug promoter, ZBRK1. The outcome of this study underscores the role of nuclear villin and its binding partner ZBRK1 in the regulation of EMT and as potential new therapeutic targets to inhibit tumorigenesis. PMID:26658611

  8. Dorsal raphe nucleus projecting retinal ganglion cells: Why Y cells?

    PubMed Central

    Pickard, Gary E.; So, Kwok-Fai; Pu, Mingliang

    2015-01-01

    Retinal ganglion Y (alpha) cells are found in retinas ranging from frogs to mice to primates. The highly conserved nature of the large, fast conducting retinal Y cell is a testament to its fundamental task, although precisely what this task is remained ill-defined. The recent discovery that Y-alpha retinal ganglion cells send axon collaterals to the serotonergic dorsal raphe nucleus (DRN) in addition to the lateral geniculate nucleus (LGN), medial interlaminar nucleus (MIN), pretectum and the superior colliculus (SC) has offered new insights into the important survival tasks performed by these cells with highly branched axons. We propose that in addition to its role in visual perception, the Y-alpha retinal ganglion cell provides concurrent signals via axon collaterals to the DRN, the major source of serotonergic afferents to the forebrain, to dramatically inhibit 5-HT activity during orientation or alerting/escape responses, which dis-facilitates ongoing tonic motor activity while dis-inhibiting sensory information processing throughout the visual system. The new data provide a fresh view of these evolutionarily old retinal ganglion cells. PMID:26363667

  9. Integration of sensory quanta in cuneate nucleus neurons in vivo.

    PubMed

    Bengtsson, Fredrik; Brasselet, Romain; Johansson, Roland S; Arleo, Angelo; Jörntell, Henrik

    2013-01-01

    Discriminative touch relies on afferent information carried to the central nervous system by action potentials (spikes) in ensembles of primary afferents bundled in peripheral nerves. These sensory quanta are first processed by the cuneate nucleus before the afferent information is transmitted to brain networks serving specific perceptual and sensorimotor functions. Here we report data on the integration of primary afferent synaptic inputs obtained with in vivo whole cell patch clamp recordings from the neurons of this nucleus. We find that the synaptic integration in individual cuneate neurons is dominated by 4-8 primary afferent inputs with large synaptic weights. In a simulation we show that the arrangement with a low number of primary afferent inputs can maximize transfer over the cuneate nucleus of information encoded in the spatiotemporal patterns of spikes generated when a human fingertip contact objects. Hence, the observed distributions of synaptic weights support high fidelity transfer of signals from ensembles of tactile afferents. Various anatomical estimates suggest that a cuneate neuron may receive hundreds of primary afferents rather than 4-8. Therefore, we discuss the possibility that adaptation of synaptic weight distribution, possibly involving silent synapses, may function to maximize information transfer in somatosensory pathways.

  10. The Nuclear Option: Evidence Implicating the Cell Nucleus in Mechanotransduction.

    PubMed

    Szczesny, Spencer E; Mauck, Robert L

    2017-02-01

    Biophysical stimuli presented to cells via microenvironmental properties (e.g., alignment and stiffness) or external forces have a significant impact on cell function and behavior. Recently, the cell nucleus has been identified as a mechanosensitive organelle that contributes to the perception and response to mechanical stimuli. However, the specific mechanotransduction mechanisms that mediate these effects have not been clearly established. Here, we offer a comprehensive review of the evidence supporting (and refuting) three hypothetical nuclear mechanotransduction mechanisms: physical reorganization of chromatin, signaling at the nuclear envelope, and altered cytoskeletal structure/tension due to nuclear remodeling. Our goal is to provide a reference detailing the progress that has been made and the areas that still require investigation regarding the role of nuclear mechanotransduction in cell biology. Additionally, we will briefly discuss the role that mathematical models of cell mechanics can play in testing these hypotheses and in elucidating how biophysical stimulation of the nucleus drives changes in cell behavior. While force-induced alterations in signaling pathways involving lamina-associated polypeptides (LAPs) (e.g., emerin and histone deacetylase 3 (HDAC3)) and transcription factors (TFs) located at the nuclear envelope currently appear to be the most clearly supported mechanism of nuclear mechanotransduction, additional work is required to examine this process in detail and to more fully test alternative mechanisms. The combination of sophisticated experimental techniques and advanced mathematical models is necessary to enhance our understanding of the role of the nucleus in the mechanotransduction processes driving numerous critical cell functions.

  11. The TLC: a novel auditory nucleus of the mammalian brain.

    PubMed

    Saldaña, Enrique; Viñuela, Antonio; Marshall, Allen F; Fitzpatrick, Douglas C; Aparicio, M-Auxiliadora

    2007-11-28

    We have identified a novel nucleus of the mammalian brain and termed it the tectal longitudinal column (TLC). Basic histologic stains, tract-tracing techniques and three-dimensional reconstructions reveal that the rat TLC is a narrow, elongated structure spanning the midbrain tectum longitudinally. This paired nucleus is located close to the midline, immediately dorsal to the periaqueductal gray matter. It occupies what has traditionally been considered the most medial region of the deep superior colliculus and the most medial region of the inferior colliculus. The TLC differs from the neighboring nuclei of the superior and inferior colliculi and the periaqueductal gray by its distinct connections and cytoarchitecture. Extracellular electrophysiological recordings show that TLC neurons respond to auditory stimuli with physiologic properties that differ from those of neurons in the inferior or superior colliculi. We have identified the TLC in rodents, lagomorphs, carnivores, nonhuman primates, and humans, which indicates that the nucleus is conserved across mammals. The discovery of the TLC reveals an unexpected level of longitudinal organization in the mammalian tectum and raises questions as to the participation of this mesencephalic region in essential, yet completely unexplored, aspects of multisensory and/or sensorimotor integration.

  12. Coexistence of central nucleus, cores, and rods: Diagnostic relevance

    PubMed Central

    Dhinakaran, Sathiyabama; Kumar, Rashmi Santhosh; Thakkar, Ravindra; Narayanappa, Gayathri

    2016-01-01

    Background: Congenital myopathies (CMs) though considered distinct disorders, simultaneous occurrence of central nucleus, nemaline rods, and cores in the same biopsy are scarcely reported. Objective: A retrospective reassessment of cases diagnosed as CMs to look for multiple pathologies missed, if any, during the initial diagnosis. Materials and Methods: Enzyme histochemical, and immunohistochemical-stained slides from 125 cases diagnosed as congenital myopathy were reassessed. Results: The study revealed 15 cases (12%) of congenital myopathy with more than one morphological feature. Central nucleus with cores (n = 11), central nucleus, nemaline rods and cores (n = 3), and nemaline rods with cores (n = 1). 4/11 cases were diagnosed as centronuclear myopathy (CNM) in the first instance; in addition, cores were revealed on reassessment. Discussion: The prevalence of CMs of all neuromuscular disorders is approximately 6 in 100,000 live births, with regional variations. Three main defined CMs include centro nuclear myopathy (CNM), nemaline rod myopathy (NRM), and central core disease (CCD). However, they are more diverse with overlapping clinical and histopathological features, thus broadening the spectra within each category of congenital myopathy. Conclusion: Identification of cases with overlap of pathological features has diagnostic relevance. PMID:27293330

  13. Action at a Distance in the Cell's Nucleus

    NASA Astrophysics Data System (ADS)

    Kondev, Jane

    Various functions performed by chromosomes involve long-range communication between DNA sequences that are tens of thousands of bases apart along the genome, and microns apart in the nucleus. In this talk I will discuss experiments and theory relating to two distinct modes of long-range communication in the nucleus, chromosome looping and protein hopping along the chromosome, both in the context of DNA-break repair in yeast. Yeast is an excellent model system for studies that link chromosome conformations to their function as there is ample experimental evidence that yeast chromosome conformations are well described by a simple, random-walk polymer model. Using a combination of polymer physics theory and experiments on yeast cells, I will demonstrate that loss of polymer entropy due to chromosome looping is the driving force for homology search during repair of broken DNA by homologous recombination. I will also discuss the spread of histone modifications along the chromosome and away from the DNA break point in the context of simple physics models based on chromosome looping and kinase hopping, and show how combining physics theory and cell-biology experiment can be used to dissect the molecular mechanism of the spreading process. These examples demonstrate how combined theoretical and experimental studies can reveal physical principles of long-range communication in the nucleus, which play important roles in regulation of gene expression, DNA recombination, and chromatin modification. This work was supported by the NSF DMR-1206146.

  14. Towards a Unified Model of Neutrino-Nucleus Reactions for Neutrino Oscillation Experiments.

    PubMed

    Nakamura, Satoshi; Kamano, Hiroyuki; Hayato, Yoshinari; Hirai, Masanori; Horiuchi, Wataru; Kumano, Shunzo; Murata, Tomoya; Saito, Koichi; Sakuda, Makoto; Sato, Toru; Suzuki, Yasuyuki

    2017-02-06

    A precise description of neutrino-nucleus reactions will play a key role in addressing fundamental questions such as the leptonic CP violation and the neutrino mass hierarchy through analyzing data from next-generation neutrino oscillation experiments. The neutrino energy relevant to the neutrino-nucleus reactions spans a broad range and, accordingly, the dominant reaction mechanism varies across the energy region from quasi-elastic scattering through nucleon resonance excitations to deep inelastic scattering. This corresponds to transitions of the effective degree of freedom for theoretical description from nucleons through meson-baryon to quarks. The main purpose of this review is to report our recent efforts towards a unified description of the neutrino-nucleus reactions over the wide energy range; recent overall progress in the field is also sketched. Starting with an overview of the current status of neutrino-nucleus scattering experiments, we formulate the cross section to be commonly used for the reactions over all the energy regions. A description of the neutrino-nucleon reactions follows and, in particular, a dynamical coupled-channels model for meson productions in and beyond the Δ(1232) region is discussed in detail. We then discuss the neutrino-nucleus reactions, putting emphasis on our theoretical approaches. We start the discussion with electroweak processes in few-nucleon systems studied with the correlated Gaussian method. Then we describe quasi-elastic scattering with nuclear spectral functions, and meson productions with a Δ-hole model. Nuclear modifications of the parton distribution functions determined through a global analysis are also discussed. Finally, we discuss issues to be addressed for future developments.

  15. PREFACE: Hot Quarks 2012: Workshop for Young Scientists on the Physics of Ultrarelativistic Nucleus-Nucleus Collisions

    NASA Astrophysics Data System (ADS)

    Bleicher, Markus; Caines, Helen; Calderón de la Barca Sanchez, Manuel; Fries, Rainer; Granier de Cassagnac, Raphaël; Hippolyte, Boris; Mischke, André; Mócsy, Ágnes; Petersen, Hannah; Ruan, Lijuan; Salgado, Carlos A.

    2013-09-01

    The 5th edition of the Workshop for Young Scientists on the Physics of Ultrarelativistic Nucleus-Nucleus Collisions (Hot Quarks 2012) was held in Copamarina, Puerto Rico from 14-20 October 2012. As in previous years, this meeting gathered more than 70 participants in the early years of their scientific careers. This issue contains the proceedings of the workshop. As in the past, the Hot Quarks workshop offered a unique atmosphere for a lively discussion and interpretation of the current measurements from high energy nuclear collisions. Recent results and upgrades at CERN's Large Hadron Collider (LHC) and Brookhaven's Relativistic Heavy Ion Collider (RHIC) were presented. Measurements from the proton-led run at the CERN-LHC were shown for the first time at this meeting. Recent theoretical developments were also extensively discussed, as well as the proposals for future facilities such as the Facility for Antiproton and Ion Research (FAIR) at Darmstadt, the Electron-Ion Collider at Brookhaven, and the LHeC. The conference's goal to provide a platform for young researchers to learn and foster their interactions was successfully met. We wish to thank the sponsors of the Hot Quarks 2012 Conference, who supported the authors of this volume: Brookhaven National Laboratory (USA), European Laboratory for Particle Physics CERN (Switzerland), European Research Council (EU), ExtreMe Matter Institute EMMI (Germany), Helmholtz International Center for FAIR (Germany), IN2P3/CNRS (France) and the European Research Council via grant #259612, Lawrence Berkeley National Laboratory (USA), Lawrence Livermore National Laboratory (USA), Los Alamos National Laboratory (USA), National Science Foundation (USA), and Netherlands Organization for Scientific Research (Netherlands). Marcus BleicherAndré Mischke Goethe-University Frankfurt and HIC4FAIRUtrecht University and Nikhef Amsterdam GermanyThe Netherlands Helen CainesÁgnes Mócsy Yale UniversityPratt Institute and Brookhaven National

  16. PREFACE: Hot Quarks 2014: Workshop for young scientists on the physics of ultrarelativistic nucleus-nucleus collisions

    NASA Astrophysics Data System (ADS)

    2015-05-01

    The 6th edition of the Workshop for Young Scientists on the Physics of Ultrarelativistic Nucleus-Nucleus Collisions (Hot Quarks 2014) was held in Las Negras, Spain from 21-28 September 2014. Following the traditions of the conference, this meeting gathered more than 70 participants in the first years of their scientific careers. The present issue contains the proceedings of this workshop. As in the past, the Hot Quarks workshop offered a unique atmosphere for a lively discussion and interpretation of the current measurements from high energy nuclear collisions. Recent results and upgrades at CERN's Large Hadron Collider (LHC) and Brookhaven's Relativistic Heavy Ion Collider (RHIC) were presented. Recent theoretical developments were also extensively discussed as well as the perspectives for future facilities such as the Facility for Antiproton and Ion Research (FAIR) at Darmstadt and the Electron-Ion Collider at Brookhaven. The conference's goal to provide a platform for young researchers to learn and foster their interactions was successfully met. We wish to thank the sponsors of the Hot Quarks 2014 Conference, who supported the authors of this volume: Brookhaven National Laboratory (USA), CPAN (Spain), Czech Science Foundation (GACR) under grant 13-20841S (Czech Republic), European Laboratory for Particle Physics CERN (Switzerland), European Research Council under grant 259612 (EU), ExtreMe Matter Institute EMMI (Germany), Helmholtz Association and GSI under grant VH-NG-822, Helmholtz International Center for FAIR (Germany), National Science Foundation under grant No.1359622 (USA), Nuclear Physics Institute ASCR (Czech Republic), Patronato de la Alhambra y Generalife (Spain) and the Universidad de Granada (Spain). Javier López Albacete, Universidad de Granada (Spain) Jana Bielcikova, Nuclear Physics Inst. and Academy of Sciences (Czech Republic) Rainer J. Fries, Texas A&M University (USA) Raphaël Granier de Cassagnac, CNRS-IN2P3 and École polytechnique (France

  17. Distinct effect of orphanin FQ in nucleus raphe magnus and nucleus reticularis gigantocellularis on the rat tail flick reflex.

    PubMed

    Yang, Z; Zhang, Y; Wu, G

    2001-06-22

    The aim of the present study is to investigate the effects of orphanin FQ (OFQ) microinjected into the nucleus raphe magnus (NRM) and the nucleus reticularis gigantocellularis (NGC) on pain modulation. The tail-flick latency (TFL) was used as a behavioral index of nociceptive responsiveness. The result showed microinjection of OFQ into the NRM significantly increased the TFL, whereas microinjection of OFQ into the NGC decreased the TFL, suggesting the analgesic effect of OFQ in the NRM and the hyperalgesic effect of OFQ in the NGC. As there are three classes of putative pain modulating neurons in the rostral ventromedial medulla (RVM), the hyperalgesic or analgesic effect of OFQ in the RVM might depend upon the different class of the neurons being acted.

  18. [Extracellular aminoacids in the amygdala and nucleus accumbens in the rat during acute pain].

    PubMed

    Silva, Elizabeth; Hernández, Luis

    2007-06-01

    In the present experiments extracellular arginine, glutamate and aspartate were studied in the basolateral nucleus of the amygdala and core of the nucleus accumbens during the formalin test (phase I). A combination of capillary zone electrophoresis with laser induced fluorescence detection and microdialysis in freely moving rats was used. Glutamate and arginine significantly increased in the nucleus accumbens after formalin injection; glutamate, arginine and aspartate significantly increased in the basolateral nucleus of the amygdala, after formalin injection. These experiments suggest that rapid neurotransmitters changes observed in the nucleus accumbens and amygdala, are possibly related to immobility and emotional states such as anxiety, aversion and/or depression caused by pain.

  19. Nucleus-encoded periplastid-targeted EFL in chlorarachniophytes.

    PubMed

    Gile, Gillian H; Keeling, Patrick J

    2008-09-01

    Chlorarachniophytes are cercozoan amoeboflagellates that acquired photosynthesis by enslaving a green alga, which has retained a highly reduced nucleus called a nucleomorph. The nucleomorph lacks many genes necessary for its own maintenance and expression, suggesting that some genes have been moved to the host nucleus and their products are now targeted back to the periplastid compartment (PPC), the reduced eukaryotic cytoplasm of the endosymbiont. Protein trafficking in chlorarachniophytes is therefore complex, including nucleus-encoded plastid-targeted proteins, nucleomorph-encoded plastid-targeted proteins, and nucleus-encoded periplastid-targeted proteins. A major gap in our understanding of this system is the PPC-targeted proteins because none have been described in any chlorarachniophytes. Here we describe the first such protein, the GTPase EFL. EFL was characterized from 7 chlorarachniophytes, and 2 distinct types were found. One is related to foraminiferan EFL and lacks an amino-terminal extension. The second, distantly related, type encodes an amino-terminal extension consisting of a signal peptide followed by sequence sharing many characteristics with transit peptides from nucleus-encoded plastid-targeted proteins and which we conclude is most likely PPC targeted. Western blotting with antibodies specific to putative host and PPC-targeted EFL from the chlorarachniophytes Bigelowiella natans and Gymnochlora stellata is consistent with posttranslational cleavage of the leaders from PPC-targeted proteins. Immunolocalization of both proteins in B. natans confirmed the cytosolic location of the leaderless EFL and a distinct localization pattern for the PPC-targeted protein but could not rule out a plastid location (albeit very unlikely). We sought other proteins with a similar leader and identified a eukaryotic translation initiation factor 1 encoding a bipartite extension with the same properties. Transit peptide sequences were characterized from all 3

  20. Superscaling in electron-nucleus scattering and its link to CC and NC QE neutrino-nucleus scattering

    SciTech Connect

    Barbaro, M. B.; Amaro, J. E.; Caballero, J. A.; González-Jiménez, R.; Donnelly, T. W.; Ivanov, M.; Udías, J. M.

    2015-05-15

    The superscaling approach (SuSA) to neutrino-nucleus scattering, based on the assumed universality of the scaling function for electromagnetic and weak interactions, is reviewed. The predictions of the SuSA model for bot CC and NC differential and total cross sections are presented and compared with the MiniBooNE data. The role of scaling violations, in particular the contribution of meson exchange currents in the two-particle two-hole sector, is explored.

  1. Superscaling in electron-nucleus scattering and its link to CC and NC QE neutrino-nucleus scattering

    NASA Astrophysics Data System (ADS)

    Barbaro, M. B.; Amaro, J. E.; Caballero, J. A.; Donnelly, T. W.; González-Jiménez, R.; Ivanov, M.; Udías, J. M.

    2015-05-01

    The superscaling approach (SuSA) to neutrino-nucleus scattering, based on the assumed universality of the scaling function for electromagnetic and weak interactions, is reviewed. The predictions of the SuSA model for bot CC and NC differential and total cross sections are presented and compared with the MiniBooNE data. The role of scaling violations, in particular the contribution of meson exchange currents in the two-particle two-hole sector, is explored.

  2. GABA and glycine receptors in the nucleus ambiguus mediate tachycardia elicited by chemical stimulation of the hypothalamic arcuate nucleus.

    PubMed

    Chitravanshi, Vineet C; Kawabe, Kazumi; Sapru, Hreday N

    2015-07-01

    We have previously reported that stimulation of the hypothalamic arcuate nucleus (ARCN) by microinjections of N-methyl-d-aspartic acid (NMDA) elicits tachycardia, which is partially mediated via inhibition of vagal inputs to the heart. The neuronal pools and neurotransmitters in them mediating tachycardia elicited from the ARCN have not been identified. We tested the hypothesis that the tachycardia elicited from the ARCN may be mediated by inhibitory neurotransmitters in the nucleus ambiguus (nAmb). Experiments were done in urethane-anesthetized, artificially ventilated, male Wistar rats. In separate groups of rats, unilateral and bilateral microinjections of muscimol (1 mM), gabazine (0.01 mM), and strychnine (0.5 mM) into the nAmb significantly attenuated tachycardia elicited by unilateral microinjections of NMDA (10 mM) into the ARCN. Histological examination of the brains showed that the microinjections sites were within the targeted nuclei. Retrograde anatomic tracing from the nAmb revealed direct bilateral projections from the ARCN and hypothalamic paraventricular nucleus to the nAmb. The results of the present study suggest that tachycardia elicited by stimulation of the ARCN by microinjections of NMDA is mediated via GABAA and glycine receptors located in the nAmb.

  3. A hypothalamic projection to the turtle red nucleus: an anterograde and retrograde tracing study.

    PubMed

    Herrick, J L; Keifer, J

    1997-10-01

    It is well known that the reptilian red nucleus lacks a descending motor cortical input to the red nucleus, but has a well-developed cerebellar input. The present study was undertaken to determine whether there is a descending rubral input that originates from the hypothalamus. Using an in vitro preparation from the turtle, injections of neurobiotin into the red nucleus resulted in retrograde labeling of neurons in the suprapeduncular nucleus of the hypothalamus. Injections of either neurobiotin or fluorescein dextran into the suprapeduncular nucleus resulted in anterograde labeling of axons and terminal boutons in the red nucleus. The majority of these terminations appeared to lie in the medial part of the red nucleus. These data have implications for the potential control of the somatic motor system of reptiles by limbic system inputs.

  4. Estimated Radiation on Mars, Hits per Cell Nucleus

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This global map of Mars shows estimates for amounts of high-energy-particle cosmic radiation reaching the surface, a serious health concern for any future human exploration of the planet.

    The estimates are based on cosmic-radiation measurements made on the way to Mars by the Mars radiation environment experiment, an instrument on NASA's 2001 Mars Odyssey spacecraft, plus information about Mars' surface elevations from the laser altimeter instrument on NASA's Mars Global Surveyor. The areas of Mars expected to have least radiation are where elevation is lowest, because those areas have more atmosphere above them to block out some of the radiation. Earth's thick atmosphere shields us from most cosmic radiation, but Mars has a much thinner atmosphere than Earth does.

    Colors in the map refer to the estimated average number of times per year each cell nucleus in a human there would be hit by a high-energy cosmic ray particle. The range is generally from two hits (color-coded green), a moderate risk level, to eight hits (coded red), a high risk level.

    NASA's Jet Propulsion Laboratory, Pasadena, Calif. manages the 2001 Mars Odyssey and Mars Global Surveyor missions for NASA's Office of Space Science, Washington D.C. The Mars radiation environment experiment was developed by NASA's Johnson Space Center. Lockheed Martin Astronautics, Denver, is the prime contractor for Odyssey, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  5. The Double Nucleus and Central Black Hole of M31

    NASA Astrophysics Data System (ADS)

    Kormendy, John; Bender, Ralf

    1999-09-01

    New spectroscopy of M31 supports Tremaine's model in which both nuclei are parts of a single eccentric disk of stars orbiting the black hole (BH). The kinematics and Hubble Space Telescope photometry are used to measure the offset of the BH from the center of mass. This confirms that the BH mass is ~3×107 Msolar by a technique that is nearly independent of stellar-dynamical models. We present spectroscopy of the nucleus of M31 obtained with the Canada-France-Hawaii Telescope and Subarcsecond Imaging Spectrograph. Spectra at the Ca infrared triplet lines (seeing σ*=0.27") are used to measure the stellar kinematics, and spectra at the Mg I b lines (σ*=0.31") are used to measure metallicities. We also measure nonparametric line-of-sight velocity distributions (LOSVDs). All spectra confirm the steep rotation and velocity dispersion gradients that imply that M31 contains a 3.3×107 Msolar central dark object. At σ*=0.27", the maximum bulge-subtracted rotation velocity of the nucleus is 233+/-4 km s-1 on the P2 side, and the maximum velocity dispersion is 287+/-9 km s-1. The dispersion peak is displaced by 0.20"+/-0.03" from the velocity center in the direction opposite to P1, confirming a result by Bacon and coworkers. The higher surface brightness nucleus, P1, is colder than the bulge, with σ~=100 km s-1 at r~=1''. Cold light from P1 contributes at the velocity center; this explains part of the σ(r) asymmetry. The nucleus is cold at r>~1'' on both sides of the center. Our results are used to test Tremaine's model in which the double nucleus is a single eccentric disk of stars orbiting the BH. (1) The model predicts that the velocity center of the nucleus is displaced by 0.2" from P2 toward P1. Our observations show a displacement of 0.08"+/-0.01" before bulge subtraction and 0.10"+/-0.01" after bulge subtraction. (2) The model predicts a minimum σ~=135 km s-1 at P1. We observe σ=123+/-2 km s-1. Observations (1) and (2) may be reconciled with the model if its

  6. Crystallization, sublimation, and gas release in the interior of a porous comet nucleus

    NASA Technical Reports Server (NTRS)

    Prialnik, Dina

    1992-01-01

    A numerical code is developed for evolutionary calculations of the thermal structure and composition of a porous comet nucleus made of water ice, in amorphous or crystalline form, other volatiles, dust, and gases trapped in amorphous ice. Bulk evaporation, crystallization, gas release, and free (Knudsen) flow of gases through the pores are taken into account. The numerical scheme yields exact conservation laws for mass and energy. The code is used to study the effect of bulk evaporation of ice in the interior of a comet nucleus during crystallization. It is found that evaporation controls the temperature distribution; the vapor prevents cooling of the crystallized layer of ice, by recondensation and release of latent heat. Thus high temperatures are maintained below the surface of the nucleus and down to depths of tens or hundreds of meters, even at large heliocentric distances, as long as crystallization goes on. Gas trapped in the ice and released during the phase transition flows both toward the interior and toward the surface and out of the nucleus. The progress of crystallization is largely determined by the contribution of gas fluxes to heat transfer.

  7. Chaos and Regularity in the Doubly Magic Nucleus 208Pb

    NASA Astrophysics Data System (ADS)

    Dietz, B.; Heusler, A.; Maier, K. H.; Richter, A.; Brown, B. A.

    2017-01-01

    High-resolution experiments have recently lead to a complete identification (energy, spin, and parity) of 151 nuclear levels up to an excitation energy of Ex=6.20 MeV in 208Pb [Heusler et al., Phys. Rev. C 93, 054321 (2016), 10.1103/PhysRevC.93.054321]. We present a thorough study of the fluctuation properties in the energy spectra of the unprecedented set of nuclear bound states. In a first approach, we group states with the same spin and parity into 14 subspectra, analyze standard statistical measures for short- and long-range correlations, i.e., the nearest-neighbor spacing distribution, the number variance Σ2, the Dyson-Mehta Δ3 statistics, and the novel distribution of the ratios of consecutive spacings of adjacent energy levels in each energy sequence, and then compute their ensemble average. Their comparison with a random matrix ensemble which interpolates between Poisson statistics expected for regular systems and the Gaussian orthogonal ensemble (GOE) predicted for chaotic systems shows that the data are well described by the GOE. In a second approach, following an idea of Rosenzweig and Porter [Phys. Rev. 120, 1698 (1960), 10.1103/PhysRev.120.1698], we consider the complete spectrum composed of the independent subspectra. We analyze their fluctuation properties using the method of Bayesian inference involving a quantitative measure, called the chaoticity parameter f , which also interpolates between Poisson (f =0 ) and GOE statistics (f =1 ). It turns out to be f ≈0.9 . This is so far the closest agreement with a GOE observed in the spectra of bound states in a nucleus. The same analysis is also performed with spectra computed on the basis of shell model calculations with different interactions (surface-delta interaction, Kuo-Brown, Michigan-three-Yukawa). While the simple surface-delta interaction exhibits features typical for nuclear many-body systems with regular dynamics, the other, more realistic interactions yield chaoticity parameters f close

  8. Weakly interacting massive particle-nucleus elastic scattering response

    NASA Astrophysics Data System (ADS)

    Anand, Nikhil; Fitzpatrick, A. Liam; Haxton, W. C.

    2014-06-01

    Background: A model-independent formulation of weakly interacting massive particle (WIMP)-nucleon scattering was recently developed in Galilean-invariant effective field theory. Purpose: Here we complete the embedding of this effective interaction in the nucleus, constructing the most general elastic nuclear cross section as a factorized product of WIMP and nuclear response functions. This form explicitly defines what can and cannot be learned about the low-energy constants of the effective theory—and consequently about candidate ultraviolet theories of dark matter—from elastic scattering experiments. Results: We identify those interactions that cannot be reliably treated in a spin-independent/spin-dependent (SI/SD) formulation: For derivative- or velocity-dependent couplings, the SI/SD formulation generally mischaracterizes the relevant nuclear operator and its multipolarity (e.g., scalar or vector) and greatly underestimates experimental sensitivities. This can lead to apparent conflicts between experiments when, in fact, none may exist. The new nuclear responses appearing in the factorized cross section are related to familiar electroweak nuclear operators such as angular momentum l⃗(i) and the spin-orbit coupling σ⃗(i).l⃗(i). Conclusions: To unambiguously interpret experiments and to extract all of the available information on the particle physics of dark matter, experimentalists will need to (1) do a sufficient number of experiments with nuclear targets having the requisite sensitivities to the various operators and (2) analyze the results in a formalism that does not arbitrarily limit the candidate operators. In an appendix we describe a code that is available to help interested readers implement such an analysis.

  9. MATURATION OF FIRING PATTERN IN CHICK VESTIBULAR NUCLEUS NEURONS

    PubMed Central

    SHAO, M.; HIRSCH, J. C.; PEUSNER, K. D.

    2007-01-01

    The principal cells of the chick tangential nucleus are vestibular nucleus neurons participating in the vestibuloocular and vestibulocollic reflexes. In birds and mammals, spontaneous and stimulus-evoked firing of action potentials is essential for vestibular nucleus neurons to generate mature vestibular reflex activity. The emergence of spike-firing pattern and the underlying ion channels were studied in morphologically-identified principal cells using whole-cell patch-clamp recordings from brain slices of late-term embryos (embryonic day 16) and hatchling chickens (hatching day 1 and hatching day 5). Spontaneous spike activity emerged around the perinatal period, since at embryonic day 16 none of the principal cells generated spontaneous action potentials. However, at hatching day 1, 50% of the cells fired spontaneously (range, 3 to 32 spikes/s), which depended on synaptic transmission in most cells. By hatching day 5, 80% of the principal cells could fire action potentials spontaneously (range, 5 to 80 spikes/s), and this activity was independent of synaptic transmission and showed faster kinetics than at hatching day 1. Repetitive firing in response to depolarizing pulses appeared in the principal cells starting around embryonic day 16, when < 20% of the neurons fired repetitively. However, almost 90% of the principal cells exhibited repetitive firing on depolarization at hatching day 1, and 100% by hatching day 5. From embryonic day 16 to hatching day 5, the gain for evoked spike firing increased almost 10-fold. At hatching day 5, a persistent sodium channel was essential for the generation of spontaneous spike activity, while a small conductance, calcium-dependent potassium current modulated both the spontaneous and evoked spike firing activity. Altogether, these in vitro studies showed that during the perinatal period, the principal cells switched from displaying no spontaneous spike activity at resting membrane potential and generating one spike on

  10. Subthalamic nucleus, sensorimotor cortex and muscle interrelationships in Parkinson's disease.

    PubMed

    Marsden, J F; Limousin-Dowsey, P; Ashby, P; Pollak, P; Brown, P

    2001-02-01

    Ten patients with Parkinson's disease were seen following bilateral or unilateral implantation of macroelectrodes into the subthalamic nucleus. Local field potentials (LFPs) were recorded from adjacent subthalamic nucleus macroelectrode (STNME) contacts simultaneously with EEG activity over the supplementary motor (Cz-FCz) and sensorimotor (C3/4-FC3/4) areas and EMG activity from the contralateral wrist extensors during isometric and phasic wrist movements. Significant coherence was seen between STNME LFPs and Cz-FCz, STNME LFPs and C3/4-FC3/4, and STNME LFPs and EMG over the range 7-45 Hz. EEG phase-led STNME LFPs by 24.4 ms (95% confidence interval 19.8 to 29.0 ms). EMG also led STNME LFPs, but time differences tended to cluster around one of two values: 6.3 ms (-0.7 to 13.3 ms) and 46.5 ms (26.2 to 66.8 ms). Recordings from the STNME contact that demonstrated the most consistent coherence with Cz-FCz in the 15-30 Hz band coincided with the contact which, when electrically stimulated at high frequencies, produced the most effective clinical response in eight out of nine (89%) subjects (P < 0.01). Oscillatory activity at 15-30 Hz may therefore prove of use in localizing the subthalamic nucleus target that provides the best clinical effect on stimulation. These results extend the hypothesis that coherent activity may be useful in binding together related activities in simultaneously active motor centres. The presence of coherence between EEG and STNME LFPs in both the beta and the gamma band (as opposed to only the beta band between EEG and cerebellar thalamus) suggests that there may be some relative frequency selectivity in the communication between different motor structures.

  11. Tractography patterns of subthalamic nucleus deep brain stimulation.

    PubMed

    Vanegas-Arroyave, Nora; Lauro, Peter M; Huang, Ling; Hallett, Mark; Horovitz, Silvina G; Zaghloul, Kareem A; Lungu, Codrin

    2016-04-01

    Deep brain stimulation therapy is an effective symptomatic treatment for Parkinson's disease, yet the precise mechanisms responsible for its therapeutic effects remain unclear. Although the targets of deep brain stimulation are grey matter structures, axonal modulation is known to play an important role in deep brain stimulation's therapeutic mechanism. Several white matter structures in proximity to the subthalamic nucleus have been implicated in the clinical benefits of deep brain stimulation for Parkinson's disease. We assessed the connectivity patterns that characterize clinically beneficial electrodes in Parkinson's disease patients, after deep brain stimulation of the subthalamic nucleus. We evaluated 22 patients with Parkinson's disease (11 females, age 57 ± 9.1 years, disease duration 13.3 ± 6.3 years) who received bilateral deep brain stimulation of the subthalamic nucleus at the National Institutes of Health. During an initial electrode screening session, one month after deep brain stimulation implantation, the clinical benefits of each contact were determined. The electrode was localized by coregistering preoperative magnetic resonance imaging and postoperative computer tomography images and the volume of tissue activated was estimated from stimulation voltage and impedance. Brain connectivity for the volume of tissue activated of deep brain stimulation contacts was assessed using probabilistic tractography with diffusion-tensor data. Areas most frequently connected to clinically effective contacts included the thalamus, substantia nigra, brainstem and superior frontal gyrus. A series of discriminant analyses demonstrated that the strength of connectivity to the superior frontal gyrus and the thalamus were positively associated with clinical effectiveness. The connectivity patterns observed in our study suggest that the modulation of white matter tracts directed to the superior frontal gyrus and the thalamus is associated with favourable clinical

  12. The Ying and Yang of the M 83 Nucleus

    NASA Astrophysics Data System (ADS)

    Mast, Damián; Díaz, Rubén J.; Dottori, Horacio A.; Agüero, María P.; Rodrigues, Irapuán; Albacete-Colombo, Juan F.

    2010-05-01

    The spiral galaxy M 83, an SB(rs)b at only 4.5 Mpc, is a privileged case for study of the detailed physics on spatial scales of a tenth of a parsec. With 3-D spectroscopic observations using CIRPASS on Gemini-S, we studied the ionized gas properties in J-band with spatial resolution of 0.″5 (Figure 1). The Paβ velocity field shows two dynamical centers, neither of them coincident with the bulge center, identified with the optical nucleus (ON) and the hidden nucleus (HN), with masses, within a radius of 10 pc, of MON = (1.8±0.4)× 107 M⊙ and MHN = (1.0±0.4)× 107 M⊙. Using the Paβ equivalent width together with population synthesis models, we are able to estimate the ages of both mass concentrations, TON = 8 Myr and THN =6-7 Myr. Adding complexity to this puzzling scenario, we used GMOS+Gemini imaging and spectroscopy to study the radio source J133658.3-295105 (Dottori et al. 2008) and find that Hα emission at the position of this source is redshifted by ~130 km s-1 with respect to an M 83 H II region, leading us to face the possibility of that we are witnessing the ejection of an object by gravitational recoil from the M 83 nucleus. A fit to the X-ray spectrum obtained Chandra supports the association between this source and the disk of M 83 by the presence of the Fe Kα line at 6.7 keV.

  13. Maturation of firing pattern in chick vestibular nucleus neurons.

    PubMed

    Shao, M; Hirsch, J C; Peusner, K D

    2006-08-25

    The principal cells of the chick tangential nucleus are vestibular nucleus neurons participating in the vestibuloocular and vestibulocollic reflexes. In birds and mammals, spontaneous and stimulus-evoked firing of action potentials is essential for vestibular nucleus neurons to generate mature vestibular reflex activity. The emergence of spike-firing pattern and the underlying ion channels were studied in morphologically-identified principal cells using whole-cell patch-clamp recordings from brain slices of late-term embryos (embryonic day 16) and hatchling chickens (hatching day 1 and hatching day 5). Spontaneous spike activity emerged around the perinatal period, since at embryonic day 16 none of the principal cells generated spontaneous action potentials. However, at hatching day 1, 50% of the cells fired spontaneously (range, 3 to 32 spikes/s), which depended on synaptic transmission in most cells. By hatching day 5, 80% of the principal cells could fire action potentials spontaneously (range, 5 to 80 spikes/s), and this activity was independent of synaptic transmission and showed faster kinetics than at hatching day 1. Repetitive firing in response to depolarizing pulses appeared in the principal cells starting around embryonic day 16, when <20% of the neurons fired repetitively. However, almost 90% of the principal cells exhibited repetitive firing on depolarization at hatching day 1, and 100% by hatching day 5. From embryonic day 16 to hatching day 5, the gain for evoked spike firing increased almost 10-fold. At hatching day 5, a persistent sodium channel was essential for the generation of spontaneous spike activity, while a small conductance, calcium-dependent potassium current modulated both the spontaneous and evoked spike firing activity. Altogether, these in vitro studies showed that during the perinatal period, the principal cells switched from displaying no spontaneous spike activity at resting membrane potential and generating one spike on

  14. Active galactic nucleus feedback in clusters of galaxies

    PubMed Central

    Blanton, Elizabeth L.; Clarke, T. E.; Sarazin, Craig L.; Randall, Scott W.; McNamara, Brian R.

    2010-01-01

    Observations made during the last ten years with the Chandra X-ray Observatory have shed much light on the cooling gas in the centers of clusters of galaxies and the role of active galactic nucleus (AGN) heating. Cooling of the hot intracluster medium in cluster centers can feed the supermassive black holes found in the nuclei of the dominant cluster galaxies leading to AGN outbursts which can reheat the gas, suppressing cooling and large amounts of star formation. AGN heating can come in the form of shocks, buoyantly rising bubbles that have been inflated by radio lobes, and the dissipation of sound waves. PMID:20351250

  15. Nucleus lentiformis--a new model for psychiatry?

    PubMed

    Sperling, W; Müller, H

    2011-05-01

    In a regions of interest analysis (ROI) of the most frequent psychiatric disorders (schizophrenia, depression, anxiety, addiction), we found the nucleus lentiformis to be the topographical brain region most frequently cited in connection with these disorders in a regions of interest survey of publications between 1990-2010. This structure, which controls particularly motorics, appears to have a much greater importance than has thus far been assumed in the control and modulation of psychiatric disorders. The question of the extent to which this region has its own control function with respect to the disorders should be addressed in further studies along with clarification of possible influence factors on the activity.

  16. Current trajectory options for a comet nucleus sample return mission

    NASA Astrophysics Data System (ADS)

    Sauer, Carl G., Jr.

    1992-08-01

    A summary of the current trajectory options available for the ESA comet nucleus sample return mission, Rosetta, is presented. These options include direct trajectories, delta-V-EGA trajectories using a Titan IV/Centaur launch vehicle with upgraded solid rocket motors, a trajectory involving a gravity assist of the earth (VEGA) prior to comet rendezvous, and one involving an additional gravity assist of the earth (VEEGA). Other propulsion options proposed and discussed are solar electric propulsion/ballistic trajectory modes and nuclear electric propulsion trajectory modes. Tables of performance data for each of these trajectory options are given.

  17. A Numerical Modeling Approach to Cometary Nucleus Surface Roughness Determination

    NASA Astrophysics Data System (ADS)

    Höfner, S.; Vincent, J.-B.; Sierks, H.; Blum, J.

    2013-09-01

    Activity of cometary nuclei is closely linked with thermophysical processes. Main catalyst to activity is the diurnal temperature wave induced by solar heating. Highly resolved comet nucleus geometric models are used to model temperatures with flat surfacial facets taken from shape modeling approaches [1, 3]. Recent analyses of Groussin et al. [4] and Davidsson et al. [2] compared thermal inertia and surface temperatures of Tempel 1 and Hartley 2 synthetic models to those derived from spectral images. They outlined that applying beaming factors and radiative self-heating is not sufficient to understand the thermal behaviour of the nucleus surface. Regions with large incidence angles (e.g. at the morning terminator) distinctively deviate from predicted temperatures. One of the main contributions to this deviation is the effect of surface roughness with scals that are considerably smaller than the model facets. Combined with a relatively low thermal inertia, temperatures cover a wide range of values even at closest neighbourhood to each other. The radiative measurement for a distant observer unveils a smearing effect that indicates higher temperatures compared to average. The authors follow two numerical approaches to model small-scale surface roughness: (A) by using randomly generated fractal surfaces and (B) by downscaling groups of facets originating from larger shape models of Tempel 1. We apply a model that accounts for both radiative heat exchange for all facets and shadowing effects due to incoming solar radiation. These values are calculated in a thermal model. The revealed temperatures are analyzed with respect to average large-scale surface temperatures. Hence, they are compared to deviating temperatures that are measured by a distant observer that is unable to resolve sub-structure surface patterns. A parametric study varying thermal inertia and the degree of surface roughness then outlines a bandwidth of feasible surface structures and relates them to

  18. Magnetic Moment of Proton Drip-Line Nucleus (9)C

    NASA Technical Reports Server (NTRS)

    Matsuta, K.; Fukuda, M.; Tanigaki, M.; Minamisono, T.; Nojiri, Y.; Mihara, M.; Onishi, T.; Yamaguchi, T.; Harada, A.; Sasaki, M.

    1994-01-01

    The magnetic moment of the proton drip-line nucleus C-9(I(sup (pi)) = 3/2, T(sub 1/2) = 126 ms) has been measured for the first time, using the beta-NMR detection technique with polarized radioactive beams. The measure value for the magnetic moment is 1mu(C-9)! = 1.3914 +/- 0.0005 (mu)N. The deduced spin expectation value of 1.44 is unusually larger than any other ones of even-odd nuclei.

  19. Subthalamic nucleus neuronal activity in Parkinson's disease and epilepsy subjects.

    PubMed

    Montgomery, Erwin B

    2008-01-01

    Activity from 113 subthalamic nucleus (STN) neurons from two epilepsy patients and 103 neurons from 9 Parkinson's disease (PD) patients undergoing DBS surgery showed no significant differences in frequencies (PD, mean 7.5+/-7.0 spikes/s (sps), epilepsy mean 7.8+/-8.5 sps) or in the coefficients of variation of mean discharge frequencies per 1s epochs. A striking relationship between mean discharge frequencies per 1 s epochs and the standard deviations for both groups were consistent with a random Poisson processes. These and similar findings call into question theories that posit increased STN activity is causal to parkinsonism.

  20. Active galactic nucleus feedback in clusters of galaxies.

    PubMed

    Blanton, Elizabeth L; Clarke, T E; Sarazin, Craig L; Randall, Scott W; McNamara, Brian R

    2010-04-20

    Observations made during the last ten years with the Chandra X-ray Observatory have shed much light on the cooling gas in the centers of clusters of galaxies and the role of active galactic nucleus (AGN) heating. Cooling of the hot intracluster medium in cluster centers can feed the supermassive black holes found in the nuclei of the dominant cluster galaxies leading to AGN outbursts which can reheat the gas, suppressing cooling and large amounts of star formation. AGN heating can come in the form of shocks, buoyantly rising bubbles that have been inflated by radio lobes, and the dissipation of sound waves.

  1. [Mutations in the personality nucleus at puberty and adolescence].

    PubMed

    Schiopu, U

    1989-01-01

    The author considers that analysing the personality by means of concrete research, the axis "self-perceptual Ego and the prospective, ideal Ego" make up an operational axis included in personality nucleus. The selected interference of the alter image about the Ego permanently readjusts this axis. In this purpose an adjective checklist and the projective test TST in two alternative have been used. The author concludes that during puberty and adolescence several changes take place as far as the number of adjective used, descriptors prevailing characteristics, and affective finality are concerned.

  2. Coherent neutrino-nucleus scattering and new neutrino interactions

    NASA Astrophysics Data System (ADS)

    Lindner, Manfred; Rodejohann, Werner; Xu, Xun-Jie

    2017-03-01

    We investigate the potential to probe new neutrino physics with future experiments measuring coherent neutrino-nucleus scattering. Experiments with high statistics should become feasible soon and allow to constrain parameters with unprecedented precision. Using a benchmark setup for a future experiment probing reactor neutrinos, we study the sensitivity on neutrino non-standard interactions and new exotic neutral currents (scalar, tensor, etc). Compared to Fermi interaction, percent and permille level strengths of the new interactions can be probed, superseding for some observables the limits from future neutrino oscillation experiments by up to two orders of magnitude.

  3. Mineralogy and Petrology of COMET WILD2 Nucleus Samples

    NASA Technical Reports Server (NTRS)

    Zolensky, Michael; Bland, Phil; Bradley, John; Brearley, Adrian; Brennan, Sean; Bridges, John; Brownlee, Donald; Butterworth, Anna; Dai, Zurong; Ebel, Denton

    2006-01-01

    The sample return capsule of the Stardust spacecraft will be recovered in northern Utah on January 15, 2006, and under nominal conditions it will be delivered to the new Stardust Curation Laboratory at the Johnson Space Center two days later. Within the first week we plan to begin the harvesting of aerogel cells, and the comet nucleus samples they contain for detailed analysis. By the time of the LPSC meeting we will have been analyzing selected removed grains for more than one month. This presentation will present the first results from the mineralogical and petrological analyses that will have been performed.

  4. Workshop on Analysis of Returned Comet Nucleus Samples

    NASA Technical Reports Server (NTRS)

    1989-01-01

    This volume contains abstracts that were accepted by the Program Committee for presentation at the workshop on the analysis of returned comet nucleus samples held in Milpitas, California, January 16 to 18, 1989. The abstracts deal with the nature of cometary ices, cryogenic handling and sampling equipment, origin and composition of samples, and spectroscopic, thermal and chemical processing methods of cometary nuclei. Laboratory simulation experimental results on dust samples are reported. Some results obtained from Halley's comet are also included. Microanalytic techniques for examining trace elements of cometary particles, synchrotron x ray fluorescence and instrument neutron activation analysis (INAA), are presented.

  5. Silencing of estrogen receptor α in the ventromedial nucleus of hypothalamus leads to metabolic syndrome

    PubMed Central

    Musatov, Sergei; Chen, Walter; Pfaff, Donald W.; Mobbs, Charles V.; Yang, Xue-Jun; Clegg, Deborah J.; Kaplitt, Michael G.; Ogawa, Sonoko

    2007-01-01

    Estrogen receptor α (ERα) plays a pivotal role in the regulation of food intake and energy expenditure by estrogens. Although it is well documented that a disruption of ERα signaling in ERα knockout (ERKO) mice leads to an obese phenotype, the sites of estrogen action and mechanisms underlying this phenomenon are still largely unknown. In the present study, we exploited RNA interference mediated by adeno-associated viral vectors to achieve focused silencing of ERα in the ventromedial nucleus of the hypothalamus, a key center of energy homeostasis. After suppression of ERα expression in this nucleus, female mice and rats developed a phenotype characteristic for metabolic syndrome and marked by obesity, hyperphagia, impaired tolerance to glucose, and reduced energy expenditure. This phenotype persisted despite normal ERα levels elsewhere in the brain. Although an increase in food intake preceded weight gain, our data suggest that a leading factor of obesity in this model is likely a decline in energy expenditure with all three major constituents being affected, including voluntary activity, basal metabolic rate, and diet-induced thermogenesis. Together, these findings indicate that ERα in the ventromedial nucleus of the hypothalamus neurons plays an essential role in the control of energy balance and the maintenance of normal body weight. PMID:17284595

  6. Peripheral injection of ghrelin induces Fos expression in the dorsomedial hypothalamic nucleus in rats

    PubMed Central

    Kobelt, Peter; Wisser, Anna-Sophia; Stengel, Andreas; Goebel, Miriam; Inhoff, Tobias; Noetzel, Steffen; Veh, Rüdiger W.; Bannert, Norbert; van der Voort, Ivo; Wiedenmann, Bertram; Klapp, Burghard F.; Taché, Yvette; Mönnikes, Hubert

    2009-01-01

    Peripheral ghrelin has been shown to act as a gut–brain peptide exerting a potent orexigenic effect on food intake. The dorsomedial nucleus of the hypothalamus (DMH) is innervated by projections from other brain areas being part of the network of nuclei controlling energy homeostasis, among others NPY/AgRP-positive fibers arising from the arcuate nucleus (ARC). The aim of the study was to determine if peripherally administered ghrelin affects neuronal activity in the DMH, as assessed by Fos expression. The number of Fos positive neurons was determined in the DMH, paraventricular nucleus of the hypothalamus (PVN), ARC, ventromedial hypothalamic nucleus (VMH), nucleus of the solitary tract (NTS) and in the area postrema(AP) in non-fasted Sprague–Dawley rats in response to intraperitoneally (ip) injected ghrelin (3 nmol/rat) or vehicle (0.15 M NaCl). Peripheral ghrelin induced a significant increase in the number of Fos-ir positive neurons/section compared with vehicle in the ARC (mean±SEM: 49±2 vs. 23±2 neurons/section, p=0.001), PVN (69±5 vs. 34±3, p=0.001), and DMH (142±5 vs. 83±5, p<0.001). Fos-ir positive neurons were mainly localized within the ventral part of the DMH. No change in Fos expression was observed in the VMH (53±8 vs. 48±6, p=0.581), NTS (42±2 vs.40±3, p=0.603), and in the AP (7±1 vs. 5±1, p=0.096). Additional double-labelling with anti-Fos and anti-AgRP revealed that Fos positive neurons in the DMH were encircled by a network of AgRP-ir positive fibers. These data indicate that peripheral ghrelin activates DMH neurons and that NPY-/AgRP-positive fibers may be involved in the response. PMID:18329635

  7. Lateral habenula and the rostromedial tegmental nucleus innervate neurochemically distinct subdivisions of the dorsal raphe nucleus in the rat.

    PubMed

    Sego, Chemutai; Gonçalves, Luciano; Lima, Leandro; Furigo, Isadora C; Donato, Jose; Metzger, Martin

    2014-05-01

    The lateral habenula (LHb) is an epithalamic structure differentiated in a medial (LHbM) and a lateral division (LHbL). Together with the rostromedial tegmental nucleus (RMTg), the LHb has been implicated in the processing of aversive stimuli and inhibitory control of monoamine nuclei. The inhibitory LHb influence on midbrain dopamine neurons has been shown to be mainly mediated by the RMTg, a mostly GABAergic nucleus that receives a dominant input from the LHbL. Interestingly, the RMTg also projects to the dorsal raphe nucleus (DR), which also receives direct LHb projections. To compare the organization and transmitter phenotype of LHb projections to the DR, direct and indirect via the RMTg, we first placed injections of the anterograde tracer Phaseolus vulgaris leucoagglutinin into the LHb or the RMTg. We then confirmed our findings by retrograde tracing and investigated a possible GABAergic phenotype of DR-projecting RMTg neurons by combining retrograde tracing with in situ hybridization for GAD67. We found only moderate direct LHb projections to the DR, which mainly emerged from the LHbM and were predominantly directed to the serotonin-rich caudal DR. In contrast, RMTg projections to the DR were more robust, emerged from RMTg neurons enriched in GAD67 mRNA, and were focally directed to a distinctive DR subdivision immunohistochemically characterized as poor in serotonin and enriched in presumptive glutamatergic neurons. Thus, besides its well-acknowledged role as a GABAergic control center for the ventral tegmental area (VTA)-nigra complex, our findings indicate that the RMTg is also a major GABAergic relay between the LHb and the DR.

  8. Investigation of the reaction mechanism for the four-particle photodisintegration of a carbon nucleus

    NASA Astrophysics Data System (ADS)

    Afanas'ev, S. N.; Gorbenko, E. S.; Khodyachikh, A. F.

    2007-05-01

    The four-particle photodisintegration of a carbon nucleus in the reactions 12C(γ, p)3H2α and 12C(γ, n)3H2α is investigated by a method that employs a diffusion chamber in a magnetic field. It is shown that these reactions proceed according a sequential-type scheme: excited states of 11B and 11C nuclei decay to weakly excited states of 8Be, 7Li, and 7Be nuclei. It is concluded that nucleons are knocked out from the s shell. In the excitation curve for the 2α system in the reaction 12C(γ, p)3H2α, a resonance is found between the maxima corresponding to the ground and the first excited state of the 8Be nucleus, and this resonance is identified as a ghost anomaly. The branching fractions of the decay modes are determined. The angular distributions of nucleons in the reaction c.m. frame are measured. The energy dependence of the asymmetry coefficient for the angular distributions is obtained. A fast increase in this coefficient is observed in the energy range 38 40 MeV. It is concluded that the asymmetry coefficient depends on the excitation energy of the final nucleus in the region of intermediate photon energies.

  9. Parametric interference effect in electron-nucleus scattering in the field of two pulsed laser waves

    NASA Astrophysics Data System (ADS)

    Roshchupkin, S. P.; Lebed', A. A.

    2014-09-01

    Electron scattering on a nucleus in a field of two unidirectional pulsed laser waves is considered. The parametric interference effect is studied, which manifests in electron scattering within the plane formed by both the direction of laser-wave propagation and the initial electron momentum (the interference region). In this kinematics the electron emits and absorbs photons of both waves in a correlated manner. The distribution of the differential cross section of the final-electron energy for the process of electron-nucleus scattering in the field of two pulsed waves is considered. This distribution in the interference region differs qualitatively and quantitatively from the corresponding distribution in any other geometry. The appearance of the parametric interference effect may be experimentally verified by measuring the energy spectrum of final electrons in the framework of modern research projects, which use sources of pulsed laser radiation (XFEL, ELI, PHELIX).

  10. First observation of an isomeric state in proton drip-line nucleus 26P

    NASA Astrophysics Data System (ADS)

    Nishimura, D.; Fukuda, M.; Sakai, T.; Tanaka, M.; Abe, K.; Chiba, J.; Fukuda, S.; Furuki, H.; Homma, A.; Hotaka, H.; Ichihashi, N.; Inaba, N.; Iwamoto, K.; Izumikawa, T.; Kamisho, Y.; Kanbe, K.; Kikukawa, N.; Kitagawa, A.; Kouno, J.; Nagashima, M.; Nakamura, Y.; Nishizuka, I.; Matsuta, K.; Mihara, M.; Miyazawa, S.; Morita, Y.; Ono, J.; Ohtsubo, T.; Sato, K.; Sato, S.; Sera, D.; Suzuki, S.; Suzuki, S.; Suzuki, T.; Takechi, M.; Tashiro, K.; Wakabayashi, M.; Watanabe, D.; Yaguchi, M.; Yamaguchi, T.; Yamaki, S.; Yasumoto, S.; Yoshinaga, K.; Zhu, Y.

    2014-03-01

    An isomeric state in the proton drip-line nucleus 26P has been observed by the γ-ray spectroscopy. The γ-ray energy and the half-life are 164.4 ± 0.1 keV and 120 ± 9 ns, respectively. For the isomeric transition of the mirror nucleus 26Na, the γ-ray energy of 82.40 ± 0.04 keV and the half-life of 4.35 ± 0.16 μs are also revised. Comparing the experimental reduced transition probabilities of 26Na and 26P with theoretical ones calculated by the shell model with the USDA interaction, the spin-parity (Jπ) of the isomeric state in 26P is most likely to be 1+.

  11. Heavy nucleus collisions between 20 and 60 GeV/nucleon

    NASA Technical Reports Server (NTRS)

    Burnett, T. H.; Dake, S.; Fuki, M.; Gregory, J. C.; Hayashi, T.; Holynski, R.; Iwai, J.; Jones, W. V.; Jurak, A.; Lord, J. J.

    1985-01-01

    Interest in studying relativistic nucleus-nucleus interations arises from the fact that they offer an opportunity to probe nuclear matter at high density and temperature. It is expected that under such extreme conditions a transition from hadronic matter into quark-gluon plasma occurs and that in the interactions of highly relativistic nuclei such conditions are created. Cosmic rays remain a unique source of high energy heavy nuclei. The Japanese-American Cooperative Emulsion Experiment (JACEE-3) was designed to study the collisions of heavy cosmic ray nuclei with different nuclear targets at energies beyond 20 GeV/nucleon. JACEE-3 experiment was carried out using a combined electronic counters and an emulsion chamber detector, which was exposed to the cosmic rays on a balloon at an altitude of 5 g/sq cm.

  12. Cytoarchitectonic and quantitative Golgi study of the hedgehog supraoptic nucleus.

    PubMed Central

    Caminero, A A; Machín, C; Sanchez-Toscano, F

    1992-01-01

    A cytoarchitectural study was made of the supraoptic nucleus (SON) of the hedgehog with special attention to the quantitative comparison of its main neuronal types. The main purposes were (1) to relate the characteristics of this nucleus in the hedgehog (a primitive mammalian insectivorous brain) with those in the SONs of more evolutionarily advanced species; (2) to identify quantitatively the dendritic fields of the main neuronal types in the hedgehog SON and to study their synaptic connectivity. From a descriptive standpoint, 3 neuronal types were found with respect to the number of dendritic stems arising from the neuronal soma: bipolar neurons (48%), multipolar neurons (45.5%) and monopolar neurons (6.5%). Within the multipolar type 2 subtypes could be distinguished, taking into account the number of dendritic spines: (a) with few spines (93%) and (b) very spiny (7%). These results indicate that the hedgehog SON is similar to that in other species except for the very spiny neurons, the significance of which is discussed. In order to characterise the main types more satisfactorily (bipolar and multipolars with few spines) we undertook a quantitative Golgi study of their dendritic fields. Although the patterns of the dendritic field are similar in both neuronal types, the differences in the location of their connectivity can reflect functional changes and alterations in relation to the synaptic afferences. Images Fig. 2 Fig. 3 Fig. 5 Fig. 6 Fig. 7 Fig. 8 Fig. 9 PMID:1452481

  13. Glucocorticoid signaling in the arcuate nucleus modulates hepatic insulin sensitivity.

    PubMed

    Yi, Chun-Xia; Foppen, Ewout; Abplanalp, William; Gao, Yuanqing; Alkemade, Anneke; la Fleur, Susanne E; Serlie, Mireille J; Fliers, Eric; Buijs, Ruud M; Tschöp, Matthias H; Kalsbeek, Andries

    2012-02-01

    Glucocorticoid receptors are highly expressed in the hypothalamic paraventricular nucleus (PVN) and arcuate nucleus (ARC). As glucocorticoids have pronounced effects on neuropeptide Y (NPY) expression and as NPY neurons projecting from the ARC to the PVN are pivotal for balancing feeding behavior and glucose metabolism, we investigated the effect of glucocorticoid signaling in these areas on endogenous glucose production (EGP) and insulin sensitivity by local retrodialysis of the glucocorticoid receptor agonist dexamethasone into the ARC or the PVN, in combination with isotope dilution and hyperinsulinemic-euglycemic clamp techniques. Retrodialysis of dexamethasone for 90 min into the ARC or the PVN did not have significant effects on basal plasma glucose concentration. During the hyperinsulinemic-euglycemic clamp, retrodialysis of dexamethasone into the ARC largely prevented the suppressive effect of hyperinsulinemia on EGP. Antagonizing the NPY1 receptors by intracerebroventricular infusion of its antagonist largely blocked the hepatic insulin resistance induced by dexamethasone in the ARC. The dexamethasone-ARC-induced inhibition of hepatic insulin sensitivity was also prevented by hepatic sympathetic denervation. These data suggest that glucocorticoid signaling specifically in the ARC neurons modulates hepatic insulin responsiveness via NPY and the sympathetic system, which may add to our understanding of the metabolic impact of clinical conditions associated with hypercortisolism.

  14. Hubble Imaging of the Nucleus of Comet ISON

    NASA Astrophysics Data System (ADS)

    Lamy, Philippe

    2013-10-01

    Comet C/2012 S1 {ISON} is both a new "nearly isotropic" and a sungrazing comet with anoutstanding apparition in cycle 21, passing within 0.42 AU of the Earth.We propose a 12-orbit Hubble postperihelion investigation of this comet that will provide a detailed view of its nucleus originating from the Oort cloud and of the possible consequences of its very close approach to the Sun at a perihelion distance of 0.012471 AU such as fragmentation.We will determine the size, shape, rotational period, and color {UBVRI} ofthe nucleus of C/2012 S1 or of its fragment should disruption occurs. This passage of a new "nearly isotropic" comet very close tothe Earth offers a rare opportunity to investigate this population ofobjects, and we expect many other observatories to attempt detecting itsnucleus in the mid-infrared, millimetric and centimetric domains.Combining the Hubble results with those from other observatories shouldyield a comprehensive picture of this NIC that can be compared to thedetailed data collected on ecliptic comets {ECs} during the past 3decades. The differences and similarities between NICs and ECs shouldyield valuable insights into the origin and evolution of comets.

  15. Extinction of a classically conditioned response: red nucleus and interpositus.

    PubMed

    Robleto, Karla; Thompson, Richard F

    2008-03-05

    It is well established that the cerebellum and its associated circuitry are essential for classical conditioning of the eyeblink response and other discrete motor responses (e.g., limb flexion, head turn, etc.) learned with an aversive unconditioned stimulus. However, brain mechanisms underlying extinction of these responses are still relatively unclear. Behavioral studies have demonstrated extinction to be an active learning process distinct from acquisition. Accordingly, this current understanding of extinction has guided neural studies that have tried to identify possible brain structures that could support this new learning. However, whether extinction engages the same brain sites necessary for acquisition is not yet clear. This poses an overriding problem for understanding brain mechanisms necessary for extinction because such analysis cannot be done without first identifying brain sites and pathways involved in this phenomenon. Equally elusive is the validity of a behavioral theory of extinction that can account for the properties of extinction. In this study, we looked at the involvement of the interpositus and the red nucleus in extinction. Results show that, although inactivation of both nuclei blocks response expression, only inactivation of the interpositus has a detrimental effect on extinction. Moreover, this detrimental effect was completely removed when inactivation of the interpositus was paired with electrical stimulation of the red nucleus. These findings speak to the important role of cerebellar structures in the extinction of discrete motor responses and provide important insight as to the validity of a particular theory of extinction.

  16. Order out of chaos in the hybrid plant nucleus.

    PubMed

    Jones, R N; Hegarty, M

    2009-01-01

    The plant nucleus is a highly ordered and dynamic structure, with a considerable level of variation between species in terms of genome size, genome organisation, chromosome territories and patterns associated with developmental changes. Diploids naturally represent the simplest state of affairs, but in the plant world more than 70% of species may have been involved in polyploidisation events at some stage during their evolution. Autopolyploids have multiple sets of chromosomes from a single species, and aside from the complexities of meiosis we may expect them to accommodate their polysomic state as well as their disomic relatives. Allopolyploids are at the other extreme, with multiple sets of chromosomes from 2 or more species, embedded in the cytoplasm of the maternal parent following hybridisation, and this presents the nucleus of nascent allopolyploids with certain zones of conflict. Nature has found ways to make the accommodation, and recent developments in molecular analysis have now opened a window for the experimenter to view the process of this adjustment, and to see how rapidly it takes place and what processes are involved. The nature of the resolution of nuclear conflicts in diploid hybrids and in allopolyploids is discussed.

  17. A thalamic input to the nucleus accumbens mediates opiate dependence

    PubMed Central

    Zhu, Yingjie; Wienecke, Carl F.R.; Nachtrab, Gregory; Chen, Xiaoke

    2016-01-01

    Chronic opiate use induces opiate dependence, which is characterized by extremely unpleasant physical and emotional feelings after drug use is terminated. Both rewarding effects of drug and the desire to avoid withdrawal symptoms motivate continued drug use1-3, and the nucleus accumbens (NAc) is important for orchestrating both processes4,5. While multiple inputs to the NAc regulate reward6-9, little is known about the NAc circuitry underlying withdrawal. Here we identify the paraventricular nucleus of the thalamus (PVT) as a prominent input to the NAc mediating the expression of opiate withdrawal induced physical signs and aversive memory. Activity in the PVT to NAc pathway is necessary and sufficient to mediate behavioral aversion. Selectively silencing this pathway abolishes aversive symptoms in two different mouse models of opiate withdrawal. Chronic morphine exposure selectively potentiates excitatory transmission between the PVT and D2-receptor-expressing medium spiny neurons (D2-MSNs) via synaptic insertion of GluA2-lacking AMPA receptors. Notably, in vivo optogenetic depotentiation restores normal transmission at PVT→D2-MSNs synapses and robustly suppresses morphine withdrawal symptoms. These results link morphine-evoked pathway- and cell type-specific plasticity in the PVT→NAc circuit to opiate dependence, and suggest that reprogramming this circuit holds promise for treating opiate addiction. PMID:26840481

  18. Neutrino-nucleus reactions based on recent structure studies

    SciTech Connect

    Suzuki, Toshio

    2015-05-15

    Neutrino-nucleus reactions are studied with the use of new shell model Hamiltonians, which have proper tensor components in the interactions and prove to be successful in the description of Gamow-Teller (GT) strengths in nuclei. The new Hamiltonians are applied to obtain new neutrino-nucleus reaction cross sections in {sup 12}C, {sup 13}C, {sup 56}Fe and {sup 56}Ni induced by solar and supernova neutrinos. The element synthesis by neutrino processes in supernova explosions is discussed with the new cross sections. The enhancement of the production yields of {sup 7}Li, {sup 11}B and {sup 55}Mn is obtained while fragmented GT strength in {sup 56}Ni with two-peak structure is found to result in smaller e-capture rates at stellar environments. The monopole-based universal interaction with tensor force of π+ρ meson exchanges is used to evaluate GT strength in {sup 40}Ar and ν-induced reactions on {sup 40}Ar. It is found to reproduce well the experimental GT strength in {sup 40}Ar.

  19. Tools for visualization of phosphoinositides in the cell nucleus.

    PubMed

    Kalasova, Ilona; Fáberová, Veronika; Kalendová, Alžběta; Yildirim, Sukriye; Uličná, Lívia; Venit, Tomáš; Hozák, Pavel

    2016-04-01

    Phosphoinositides (PIs) are glycerol-based phospholipids containing hydrophilic inositol ring. The inositol ring is mono-, bis-, or tris-phosphorylated yielding seven PIs members. Ample evidence shows that PIs localize both to the cytoplasm and to the nucleus. However, tools for direct visualization of nuclear PIs are limited and many studies thus employ indirect approaches, such as staining of their metabolic enzymes. Since localization and mobility of PIs differ from their metabolic enzymes, these approaches may result in incomplete data. In this paper, we tested commercially available PIs antibodies by light microscopy on fixed cells, tested their specificity using protein-lipid overlay assay and blocking assay, and compared their staining patterns. Additionally, we prepared recombinant PIs-binding domains and tested them on both fixed and live cells by light microscopy. The results provide a useful overview of usability of the tools tested and stress that the selection of adequate tools is critical. Knowing the localization of individual PIs in various functional compartments should enable us to better understand the roles of PIs in the cell nucleus.

  20. Capsaicin augments synaptic transmission in the rat medial preoptic nucleus.

    PubMed

    Karlsson, Urban; Sundgren-Andersson, Anna K; Johansson, Staffan; Krupp, Johannes J

    2005-05-10

    The medial preoptic nucleus (MPN) is the major nucleus of the preoptic area (POA), a hypothalamic area involved in the regulation of body-temperature. Injection of capsaicin into this area causes hypothermia in vivo. Capsaicin also causes glutamate release from hypothalamic slices. However, no data are available on the effect of capsaicin on synaptic transmission within the MPN. Here, we have studied the effect of exogenously applied capsaicin on spontaneous synaptic activity in hypothalamic slices of the rat. Whole-cell patch-clamp recordings were made from visually identified neurons located in the MPN. In a subset of the studied neurons, capsaicin enhanced the frequency of spontaneous glutamatergic EPSCs. Remarkably, capsaicin also increased the frequency of GABAergic IPSCs, an effect that was sensitive to removal of extracellular calcium, but insensitive to tetrodotoxin. This suggests an action of capsaicin at presynaptic GABAergic terminals. In contrast to capsaicin, the TRPV4 agonist 4alpha-PDD did not affect GABAergic IPSCs. Our results show that capsaicin directly affects synaptic transmission in the MPN, likely through actions at presynaptic terminals as well as on projecting neurons. Our data add to the growing evidence that capsaicin receptors are not only expressed in primary afferent neurons, but also contribute to synaptic processing in some CNS regions.

  1. Finding Hierarchical and Overlapping Dense Subgraphs using Nucleus Decompositions

    SciTech Connect

    Seshadhri, Comandur; Pinar, Ali; Sariyuce, Ahmet Erdem; Catalyurek, Umit

    2014-11-01

    Finding dense substructures in a graph is a fundamental graph mining operation, with applications in bioinformatics, social networks, and visualization to name a few. Yet most standard formulations of this problem (like clique, quasiclique, k-densest subgraph) are NP-hard. Furthermore, the goal is rarely to nd the \\true optimum", but to identify many (if not all) dense substructures, understand their distribution in the graph, and ideally determine a hierarchical structure among them. Current dense subgraph nding algorithms usually optimize some objective, and only nd a few such subgraphs without providing any hierarchy. It is also not clear how to account for overlaps in dense substructures. We de ne the nucleus decomposition of a graph, which represents the graph as a forest of nuclei. Each nucleus is a subgraph where smaller cliques are present in many larger cliques. The forest of nuclei is a hierarchy by containment, where the edge density increases as we proceed towards leaf nuclei. Sibling nuclei can have limited intersections, which allows for discovery of overlapping dense subgraphs. With the right parameters, the nuclear decomposition generalizes the classic notions of k-cores and k-trusses. We give provable e cient algorithms for nuclear decompositions, and empirically evaluate their behavior in a variety of real graphs. The tree of nuclei consistently gives a global, hierarchical snapshot of dense substructures, and outputs dense subgraphs of higher quality than other state-of-theart solutions. Our algorithm can process graphs with tens of millions of edges in less than an hour.

  2. The Cell Nucleus in Physiological and Experimentally Induced Hypometabolism

    NASA Astrophysics Data System (ADS)

    Malatesta, M.

    The main problem for manned space mission is, at present, represented by the mass penalty associated to the human presence. An efficient approach could be the induction of a hypometabolic stasis in the astronauts, thus drastically reducing the physical and psychological requirements of the crew. On the other hand, in the wild, a reduction in resource consumptions physiologi- cally occurs in certain animals which periodically enter hibernation, a hypometabolic state in which both the energy need and energy offer are kept at a minimum. During the last twelve years, we have been studying different tissues of hibernating dormice, with the aim of analyzing their features during the euthermia -hibernation-arousal cycle as well as getting insight into the mechanisms allowing adaptation to hypometabolism. We paid particular attention to the cell nucleus, as it is the site of chief metabolic functions, such as DNA replication and RNA transcription. Our observations revealed no significant modification in the basic features of cell nuclei during hibernation; however, the cell nuclei of hibernating dormice showed unusual nuclear bodies containing molecules involved in RNA pathways. Therefore, we supposed that they could represent storage/assembly sites of several factors for processing some RNA which could be slowly synthesised during hibernation and rapidly and abundantly released in early arousal in order to meet the increased metabolic needs of the cell. The nucleolus also underwent structural and molecular modifications during hibernation, maybe to continue important nucleolar functions, or, alternatively, permit a most efficient reactivation upon arousal. On the basis of the observations made in vivo , we recently tried to experimentally induce a reversible hypometabolic state in in vitro models, using cell lines derived from hibernating and non-hibernating species. By administering the synthetic opioid DADLE, we could significantly reduce both RNA transcrip- tion and

  3. Fission fragment mass distributions in reactions forming the {sup 213}Fr compound nucleus

    SciTech Connect

    Appannababu, S.; Mukherjee, S.; Deshmukh, N. N.; Rath, P. K.; Singh, N. L.; Nayak, B. K.; Thomas, R. G.; Choudhury, R. K.; Sugathan, P.; Jhingan, A.; Negi, D.; Prasad, E.

    2011-03-15

    The fission fragment mass angle correlations and mass ratio distributions have been investigated for the two systems {sup 16}O+{sup 197}Au and {sup 27}Al+{sup 186}W, leading to the same compound nucleus {sup 213}Fr around the Coulomb barrier energies. Systematic analysis of the variance of the mass distributions as a function of temperature and angular momentum suggests true compound nuclear fission for both the reactions, indicating the absence of nonequilibrium fission processes.

  4. [Lateral motor nucleus in the lumbosacral segment of the spinal cord of the horse].

    PubMed

    Flieger, S; Sławomirski, J; Boratyński, Z; Jastrzebski, M

    1984-01-01

    Two medullae oblongatae of horses were cut into 15 microns cross-sections and stained according to the modified method of Nissel. The lateral motor nucleus lies in the lateral and median part of the ventral column of spinal cord grey matter. It adjoins medially nucleus motorius medialis of the spinal ventral column. Cells of this nucleus occur both along the whole lumbar and sacral segment of the spinal cord. In the lateral motor nucleus three cell groups are distinguished - median, basal and lateral. The latter is divided in some segments into subgroups - dorsal and ventral. Along the nucleus quite numerous constrictions and intervals are found, which are caused by various numbers of cells in particular cross-sections. Nucleus motorius lateralis is formed mainly of large and medium multipolar or single spindle cells.

  5. [Nucleus motorius lateralis in the lumbosacral segment of the spinal cord in horses].

    PubMed

    Flieger, S; Sławomirski, J; Boratyński, Z; Jastrzebski, M

    1984-01-01

    Two medullae oblongatae of horses were cut into 15 microns cross-sections and stained according to the modified method of Nissel. The lateral motor nucleus lies in the lateral and median part of the ventral column of spinal cord grey matter. It adjoins medially nucleus motorius medialis of the spinal ventral column. Cells of this nucleus occur both along the whole lumbar and sacral segment of the spinal cord. In the lateral motor nucleus three cell groups are distinguished-median, basal and lateral. The latter is divided in some segments into subgroups-dorsal and ventral. Along the nucleus quite numerous constrictions and intervals are found, which are caused by various numbers of cells in particular cross-sections. Nucleus motorius lateralis is formed mainly of large and medium multipolar or single spindle cells.

  6. Selective Stimulation and Measurement in the Cochlear Nucleus With the Spike Microelectrode Array

    DTIC Science & Technology

    2007-11-02

    Selective Stimulation and Measurement in the Cochlear Nucleus with the Spike Microelectrode Array F. MASE1, H. TAKAHASHI1, T. EJIRI1, M. NAKAO1, N...aren’t always effective, because we don’t have sufficient knowledge of the auditory pathways and the Cochlear Nucleus (CN) functions to stimulate the... Cochlear Nucleus functionally. Our goals are to enhance our understanding of such functions and to develop effective stimulating strategies of the CN

  7. Effects of systemic L-tyrosine on dopamine release from rat corpus striatum and nucleus accumbens

    NASA Technical Reports Server (NTRS)

    During, Matthew J.; Acworth, Ian N.; Wurtman, Richard J.

    1988-01-01

    Intracerebral dialysis was used to monitor extracellular fluid from rat striatum and nucleus accumbens following the intraperitoneal administration of tyrosine. Dopamine concentrations in dialysates from both the striatum and the nucleus accumbens increased significantly in response to the tyrosine. The magnitude of the tyrosine effect was greater in the nucleus accumbens than in the striatum. Hence, mesolimbic dopaminergic neurons may be especially responsive to precursor availability.

  8. 14N + 13C fusion cross sections and compound nucleus limitation in 27Al

    NASA Astrophysics Data System (ADS)

    Digregorio, D. E.; Gomez del Campo, J.; Chan, Y. D.; Ford, J. L. C., Jr.; Shapira, D.; Ortiz, M. E.

    1982-10-01

    Fusion cross sections for the 14N + 13C system have been measured by detecting the evaporation residues at five bombarding energies which correspond to high excitation energies in the compound nucleus: E*(27Al)=64-110 MeV. The 27Al nucleus can be populated by four different heavy-ion entrance channels-15N + 12C, 16O + 11B, 14N + 13C, and 17O + 10B-which are accessible to experimental measurements. Comparing the present data with those already existing for the above channels, it is found that for E*>60 MeV the curves E* vs Jcr for each system converge, which may be indicative of a limitation imposed by the compound nucleus. The data are discussed in terms of existing models for entrance channel and statistical yrast line limitations. The highest energy point also suggests the existence of a maximum absolute angular momentum limit of ~28ℏ. NUCLEAR REACTIONS 14N + 13C E(14N)=86.0, 103.8, 149.0, 161.3, and 180.0 MeV; measured d2σdΩdE for reaction products from Z=5 to 12. Extracted σfus, σD, σR.

  9. Superallowed Gamow-Teller decay of the doubly magic nucleus 100Sn.

    PubMed

    Hinke, C B; Böhmer, M; Boutachkov, P; Faestermann, T; Geissel, H; Gerl, J; Gernhäuser, R; Górska, M; Gottardo, A; Grawe, H; Grębosz, J L; Krücken, R; Kurz, N; Liu, Z; Maier, L; Nowacki, F; Pietri, S; Podolyák, Zs; Sieja, K; Steiger, K; Straub, K; Weick, H; Wollersheim, H-J; Woods, P J; Al-Dahan, N; Alkhomashi, N; Ataç, A; Blazhev, A; Braun, N F; Čeliković, I T; Davinson, T; Dillmann, I; Domingo-Pardo, C; Doornenbal, P C; de France, G; Farrelly, G F; Farinon, F; Goel, N; Habermann, T C; Hoischen, R; Janik, R; Karny, M; Kaşkaş, A; Kojouharov, I M; Kröll, Th; Litvinov, Y; Myalski, S; Nebel, F; Nishimura, S; Nociforo, C; Nyberg, J; Parikh, A R; Procházka, A; Regan, P H; Rigollet, C; Schaffner, H; Scheidenberger, C; Schwertel, S; Söderström, P-A; Steer, S J; Stolz, A; Strmeň, P

    2012-06-20

    The shell structure of atomic nuclei is associated with 'magic numbers' and originates in the nearly independent motion of neutrons and protons in a mean potential generated by all nucleons. During β(+)-decay, a proton transforms into a neutron in a previously not fully occupied orbital, emitting a positron-neutrino pair with either parallel or antiparallel spins, in a Gamow-Teller or Fermi transition, respectively. The transition probability, or strength, of a Gamow-Teller transition depends sensitively on the underlying shell structure and is usually distributed among many states in the neighbouring nucleus. Here we report measurements of the half-life and decay energy for the decay of (100)Sn, the heaviest doubly magic nucleus with equal numbers of protons and neutrons. In the β-decay of (100)Sn, a large fraction of the strength is observable because of the large decay energy. We determine the largest Gamow-Teller strength so far measured in allowed nuclear β-decay, establishing the 'superallowed' nature of this Gamow-Teller transition. The large strength and the low-energy states in the daughter nucleus, (100)In, are well reproduced by modern, large-scale shell model calculations.

  10. Amygdaloid and basal forebrain direct connections with the nucleus of the solitary tract and the dorsal motor nucleus

    SciTech Connect

    Schwaber, J.S.; Kapp, B.S.; Higgins, G.A.; Rapp, P.R.

    1982-10-01

    Although the amygdala complex has long been known to exert a profound influence on cardiovascular activity, the neuronal and connectional substrate mediating these influences remains unclear. This paper describes a direct amygdaloid projection to medullary sensory and motor structures involved in cardiovascular regulation, the nucleus of the solitary tract (NTS) and the dorsal motor nucleus (DVN), by the use of autoradiographic anterograde transport and retrograde horseradish peroxidase (HRP) techniques in rabbits. Since all of these structures are highly heterogeneous structurally and functionally, details of the specific areas of the neuronal origin and efferent distribution of the projection were examined in relation to these features and with reference to a cytoarchitecture description of the relevant forebrain regions in the rabbit. The existence of such an extensive projection system connecting these specific regions found in these studies is significant evidence in support to its potential for participation in the amygdaloid expression of cardiovascular influences and has important implications for the cellular analysis of the functional role of these influences.

  11. Role of the red nucleus in suppressing the jaw-opening reflex following stimulation of the raphe magnus nucleus.

    PubMed

    Satoh, Yoshihide; Ishizuka, Ken'Ichi; Iwasaki, Shin-ichi

    2014-08-01

    In a previous study, we found that electrical and chemical stimulation of the red nucleus (RN) suppressed the high-threshold afferent-evoked jaw-opening reflex (JOR). It has been reported that the RN receives bilaterally projection fibers from the raphe magnus nucleus (RMg), and that stimulation of the RMg inhibits the tooth pulp-evoked nociceptive JOR. These facts imply that RMg-induced inhibition of the JOR could be mediated via the RN. The present study first examines whether stimulation of the RMg suppresses the high-threshold afferent-evoked JOR. The JOR was evoked by electrical stimulation of the inferior alveolar nerve (IAN), and was recorded as the electromyographic response of the anterior belly of the digastric muscle. The stimulus intensity was 4.0 (high-threshold) times the threshold. Conditioning electrical stimulation of the RMg significantly suppressed the JOR. A further study then examined whether electrically induced lesions of the RN or microinjection of muscimol into the RN affects RMg-induced suppression of the JOR. Electrically induced lesions of the bilateral RN and microinjection of muscimol into the bilateral RN both reduced the RMg-induced suppression of the JOR. These results suggest that RMg-induced suppression of the high-threshold afferent-evoked JOR is mediated by a relay in the RN.

  12. Chronic alcohol exposure alters transcription broadly in a key integrative brain nucleus for homeostasis: the nucleus tractus solitarius.

    PubMed

    Covarrubias, Maria Yolanda; Khan, Rishi L; Vadigepalli, Rajanikanth; Hoek, Jan B; Schwaber, James S

    2005-12-14

    Chronic exposure to alcohol modifies physiological processes in the brain, and the severe symptoms resulting from sudden removal of alcohol from the diet indicate that these modifications are functionally important. We investigated the gene expression patterns in response to chronic alcohol exposure (21-28 wk) in the rat nucleus tractus solitarius (NTS), a brain nucleus with a key integrative role in homeostasis and cardiorespiratory function. Using methods and an experimental design optimized for detecting transcriptional changes less than twofold, we found 575 differentially expressed genes. We tested these genes for significant associations with physiological functions and signaling pathways using Gene Ontology terms and the Kyoto Encyclopedia of Genes and Genomes (KEGG) database, respectively. Chronic alcohol exposure resulted in significant NTS gene regulation related to the general processes of synaptic transmission, intracellular signaling, and cation transport as well as specific neuronal functions including plasticity and seizure behavior that could be related to alcohol withdrawal symptoms. The differentially expressed genes were also significantly enriched for enzymes of lipid metabolism, glucose metabolism, oxidative phosphorylation, MAP kinase signaling, and calcium signaling pathways from KEGG. Intriguingly, many of the genes we found to be differentially expressed in the NTS are known to be involved in alcohol-induced oxidative stress and/or cell death. The study provides evidence of very extensive alterations of physiological gene expression in the NTS in the adapted state to chronic alcohol exposure.

  13. Topography and morphology of the inhibitory projection from superior olivary nucleus to nucleus laminaris in chickens (Gallus gallus).

    PubMed

    Tabor, Kathryn M; Wong, Rachel O L; Rubel, Edwin W

    2011-02-01

    The avian nucleus laminaris (NL) is involved in computation of interaural time differences (ITDs) that encode the azimuthal position of a sound source. Neurons in NL are bipolar, with dorsal and ventral dendritic arbors receiving input from separate ears. NL neurons act as coincidence detectors that respond maximally when input from each ear arrives at the two dendritic arbors simultaneously. Computational and physiological studies demonstrated that the sensitivity of NL neurons to coincident inputs is modulated by an inhibitory feedback circuit via the superior olivary nucleus (SON). To understand the mechanism of this modulation, the topography of the projection from SON to NL was mapped, and the morphology of the axon terminals of SON neurons in NL was examined in chickens (Gallus gallus). In vivo injection of AlexaFluor 568 dextran amine into SON demonstrated a coarse topographic projection from SON to NL. Retrogradely labeled neurons in NL were located within the zone of anterogradely labeled terminals, suggesting a reciprocal projection between SON to NL. In vivo extracellular physiological recording further demonstrated that this topography is consistent with tonotopic maps in SON and NL. In addition, three-dimensional reconstruction of single SON axon branches within NL revealed that individual SON neurons innervate a large area of NL and terminate on both dorsal and ventral dendritic arbors of NL neurons. The organization of the projection from SON to NL supports its proposed functions of controlling the overall activity level of NL and enhancing the specificity of frequency mapping and ITD detection.

  14. Epidermal growth factor receptors destined for the nucleus are internalized via a clathrin-dependent pathway

    SciTech Connect

    De Angelis Campos, Ana Carolina; Rodrigues, Michele Angela; Andrade, Carolina de; Miranda de Goes, Alfredo; Nathanson, Michael H.; Gomes, Dawidson A.

    2011-08-26

    Highlights: {yields} EGF and its receptor translocates to the nucleus in liver cells. {yields} Real time imaging shows that EGF moves to the nucleus. {yields} EGF moves with its receptor to the nucleus. {yields} Dynamin and clathrin are necessary for EGFR nuclear translocation. -- Abstract: The epidermal growth factor (EGF) transduces its actions via the EGF receptor (EGFR), which can traffic from the plasma membrane to either the cytoplasm or the nucleus. However, the mechanism by which EGFR reaches the nucleus is unclear. To investigate these questions, liver cells were analyzed by immunoblot of cell fractions, confocal immunofluorescence and real time confocal imaging. Cell fractionation studies showed that EGFR was detectable in the nucleus after EGF stimulation with a peak in nuclear receptor after 10 min. Movement of EGFR to the nucleus was confirmed by confocal immunofluorescence and labeled EGF moved with the receptor to the nucleus. Small interference RNA (siRNA) was used to knockdown clathrin in order to assess the first endocytic steps of EGFR nuclear translocation in liver cells. A mutant dynamin (dynamin K44A) was also used to determine the pathways for this traffic. Movement of labeled EGF or EGFR to the nucleus depended upon dynamin and clathrin. This identifies the pathway that mediates the first steps for EGFR nuclear translocation in liver cells.

  15. Nucleus-nucleus interaction above several hundred GeV/n

    NASA Technical Reports Server (NTRS)

    Burnett, T. H.; Dake, S.; Fuki, M.; Gregory, J. C.; Hayashi, T.; Holynski, R.; Iwai, J.; Jones, W. V.; Jurak, A.; Lord, J. J.

    1985-01-01

    The Japanese-American Cooperative Emulsion Experiment (JACEE) have been investigating high energy nuclear interactions of cosmic ray nuclei by means of balloon-borne emulsion chamber. Current exposure parameters are listed. Analysis of the last two experiments (JACEE4 and JACEE5) are still in progress. A result of semi-inclusive analysis of a sample set of central collision events is presented here, concerning multiplicity, rapidity fluctuation for extremely high multiplicity events and correlation between transverse momentum and estimated energy density.

  16. Clues to the Mystery of the M31 Nucleus

    NASA Astrophysics Data System (ADS)

    Crane, Ph.

    1995-03-01

    HST imaging of the nucleus of M31 (Lauer et al.,1993; King, Stanford, and Crane, 1995) revealed a double structure in which the brightest point in the V band(P1) is not centered on the outer isophotes but rather the fainter peak is. Interestingly, the fainter peak in V(P2) is the brightest point in the UV and is very close the center of the outer isophotes. The colour of P1 matches that of the reddened ''bowl'' of stars surrounding P2 found by King et al. Further complication is found in the spectra of the M31 nucleus (Bacon et al.,1994) where the symmetric rotation curve shows no evidence of the brightest point P1. Additionally, the peak in the velocity dispersion does not lie at either of these peaks, but is shifted along the line joining them to the side of P2 away from P1. A simple model of the nucleus of M31 apparently can resolve these anomalies. The model assumes that P1 is a low velocity dispersion object in the gravitational field of P2. P2 and the surrounding stars rotate about a line perpendicular to the line joining P1 and P2. The model generates a 2-dimensional array of spectra using the HST imaging data as a reference for the brightness at each point. The models are convolved with a seeing function and then observed. The symmetry of the rotation curve is easily reproduced. The shift of the velocity dispersion curve is also produced. The model can restrict the range of velocity dispersions of P1, and the velocity of P1 relative to P2. The main objection to the model is that it implies that we are seeing P1 as it is being tidally disrupted in the field of P2. However, some evidence that this is indeed the case comes from the observation of the ''bowl'' of stars surrounding P2 mentioned above. Bacon et al.,1994, A. & A. 281,691. Lauer et al.,1993, A.J. 106,1436. King, Stanford, and Crane, 1995, A.J. 109,164.

  17. Tonotopic Optimization for Temporal Processing in the Cochlear Nucleus

    PubMed Central

    Oline, Stefan N.; Ashida, Go

    2016-01-01

    In the auditory system, sounds are processed in parallel frequency-tuned circuits, beginning in the cochlea. Auditory nerve fibers reflect this tonotopy and encode temporal properties of acoustic stimuli by “locking” discharges to a particular stimulus phase. However, physiological constraints on phase-locking depend on stimulus frequency. Interestingly, low characteristic frequency (LCF) neurons in the cochlear nucleus improve phase-locking precision relative to their auditory nerve inputs. This is proposed to arise through synaptic integration, but the postsynaptic membrane's selectivity for varying levels of synaptic convergence is poorly understood. The chick cochlear nucleus, nucleus magnocellularis (NM), exhibits tonotopic distribution of both input and membrane properties. LCF neurons receive many small inputs and have low input thresholds, whereas high characteristic frequency (HCF) neurons receive few, large synapses and require larger currents to spike. NM therefore presents an opportunity to study how small membrane variations interact with a systematic topographic gradient of synaptic inputs. We investigated membrane input selectivity and observed that HCF neurons preferentially select faster input than their LCF counterparts, and that this preference is tolerant of changes to membrane voltage. We then used computational models to probe which properties are crucial to phase-locking. The model predicted that the optimal arrangement of synaptic and membrane properties for phase-locking is specific to stimulus frequency and that the tonotopic distribution of input number and membrane excitability in NM closely tracks a stimulus-defined optimum. These findings were then confirmed physiologically with dynamic-clamp simulations of inputs to NM neurons. SIGNIFICANCE STATEMENT One way that neurons represent temporal information is by phase-locking, which is discharging in response to a particular phase of the stimulus waveform. In the auditory system

  18. Gas streaming motions towards the nucleus of M81

    NASA Astrophysics Data System (ADS)

    Schnorr Müller, Allan; Storchi-Bergmann, Thaisa; Riffel, Rogemar A.; Ferrari, Fabricio; Steiner, J. E.; Axon, David J.; Robinson, Andrew

    2011-05-01

    We present two-dimensional stellar and gaseous kinematics of the inner 120 × 250 pc2 of the LINER/Seyfert 1 galaxy M81, from optical spectra obtained with the Gemini Multi-Object Spectrograph (GMOS) integral field spectrograph on the Gemini-North telescope at a spatial resolution of ≈10 pc. The stellar velocity field shows circular rotation and, overall, is very similar to the published large-scale velocity field, but deviations are observed close to the minor axis which can be attributed to stellar motions possibly associated with a nuclear bar. The stellar velocity dispersion of the bulge is 162 ± 15 km s-1, in good agreement with previous measurements and leading to a black hole mass of MBH= 5.5+3.6-2.0× 107 M⊙ based on the MBH-σ relationship. The gas kinematics is dominated by non-circular motions and the subtraction of the stellar velocity field reveals blueshifts of ≈-100 km s-1 on the far side of the galaxy and a few redshifts on the near side. These characteristics can be interpreted in terms of streaming towards the centre if the gas is in the plane. On the basis of the observed velocities and geometry of the flow, we estimate a mass inflow rate in ionized gas of ≈4.0 × 10-3 M⊙ yr-1, which is of the order of the accretion rate necessary to power the LINER nucleus of M81. We have also applied the technique of principal component analysis (PCA) to our data, which reveals the presence of a rotating nuclear gas disc within ≈50 pc from the nucleus and a compact outflow, approximately perpendicular to the disc. The PCA combined with the observed gas velocity field shows that the nuclear disc is being fed by gas circulating in the galaxy plane. The presence of the outflow is supported by a compact jet seen in radio observations at a similar orientation, as well as by an enhancement of the [O I]/Hα line ratio, probably resulting from shock excitation of the circumnuclear gas by the radio jet. With these observations we are thus resolving both the

  19. Probing the Nucleus with Deuteron+Gold Collisions at RHIC

    NASA Astrophysics Data System (ADS)

    Citron, Zvi Hirsh

    2011-12-01

    The Relativistic Heavy Ion Collider (RHIC) was built to produce and study Quark Gluon Plasma (QGP), the phase of matter thought to exist under conditions sufficiently hot and dense to create a medium in which the degrees of freedom are quarks and gluons rather than color neutral hadrons. Already in its early years of running, the data from RHIC provided tantalizing evidence of QGP signatures in Au+Au collisions at sNN = 200 GeV. A crucial part of understanding the putative QGP in Au+Au collisions is to have both a well understood reference as well as a robust control experiment. Proton-proton collisions at the same sNN serve as the baseline for heavy ion collisions at RHIC, and play an invaluable role in setting our frame of reference in interactions that do not create any nuclear medium. For the control experiment, RHIC's ability to collide asymmetric beams is utilized and d+Au collisions are used. Unlike p+p collisions, in the d+Au system there is a nuclear medium present---the heavy Au nucleus---and so we may study this system to distinguish initial state cold nuclear matter effects from final state effects that occur in the hot dense medium of Au+Au collisions. Beyond its use as a control experiment, the d+Au collision system presents the opportunity for important study of nuclear and nucleonic structure, it is after all necessary for our colored parton theory to operate in the nucleus as well as in a QGP. Deuteron - gold collisions at RHIC are a powerful tool for shedding light on cold nuclear matter effects. This thesis describes two analyses of d+Au collisions measured by the PHENIX experiment at RHIC. The first is a measurement of the midrapidity yield of unidentified charged hadrons in the 2003 RHIC run. This is used a key baseline for understanding particle production in Au+Au collisions as well as a detailed look at the Cronin effect. The second analysis measures rapidity separated two-particle production where one of the particles is at either forward

  20. Hindered proton collectivity in the proton-rich nucleus 28S: Possible magic number Z = 16

    NASA Astrophysics Data System (ADS)

    Togano, Y.; Yamada, Y.; Iwasa, N.; Yamada, K.; Motobayashi, T.; Aoi, N.; Baba, H.; Bishop, S.; Cai, X.; Doornenbal, P.; Fang, D.; Furukawa, T.; Ieki, K.; Kawabata, T.; Kanno, S.; Kobayashi, N.; Kondo, Y.; Kuboki, T.; Kume, N.; Kurita, K.; Kurokawa, M.; Ma, Y. G.; Matsuo, Y.; Murakami, H.; Matsushita, M.; Nakamura, T.; Okada, K.; Ota, S.; Satou, Y.; Shimoura, S.; Shioda, R.; Tanaka, K. N.; Takeuchi, S.; Tian, W.; Wang, H.; Wang, J.; Yoneda, K.

    2012-10-01

    The reduced transition probability B(E2;0gs+→21+) for the proton-rich nucleus 28S was determined experimentally using intermediate-energy Coulomb excitation. The resultant B(E2) value 181(31) e2fm4 is smaller than those of neighboring N = 12 isotones and Z = 16 isotopes. The double ratio |Mn/Mp|/(N/Z) of the 0gs+→21+ transition in 28S was obtained to be 1.9(2) by evaluating the Mn value from the known B(E2) value of the mirror nucleus 28Mg, showing the hindrance of proton collectivity relative to that of neutrons. These results indicate the emergence of the magic number Z = 16 in 28S.

  1. New shape isomer in the self-conjugate nucleus 72Kr.

    PubMed

    Bouchez, E; Matea, I; Korten, W; Becker, F; Blank, B; Borcea, C; Buta, A; Emsallem, A; de France, G; Genevey, J; Hannachi, F; Hauschild, K; Hürstel, A; Le Coz, Y; Lewitowicz, M; Lucas, R; Negoita, F; de Oliveira Santos, F; Pantelica, D; Pinston, J; Rahkila, P; Rejmund, M; Stanoiu, M; Theisen, Ch

    2003-02-28

    A new isomeric 0(+) state was identified as the first excited state in the self-conjugate (N=Z) nucleus 72Kr. By combining for the first time conversion-electron and gamma-ray spectroscopy with the production of metastable states in high-energy fragmentation, the electric-monopole decay of the new isomer to the ground state was established. The new 0(+) state is understood as the band head of the known prolate rotational structure, which strongly supports the interpretation that 72Kr is one of the rare nuclei having an oblate-deformed ground state. This observation gives in fact the first evidence for a shape isomer in a N=Z nucleus.

  2. Fluctuations of the multiplicity of produced particles in onium-nucleus collisions

    NASA Astrophysics Data System (ADS)

    Liou, Tseh; Mueller, A. H.; Munier, S.

    2017-01-01

    We address the general features of event-by-event fluctuations of the multiplicity of gluons produced in the scattering of a dilute hadron off a large nucleus at high energy in the fragmentation region of the dilute hadron. We relate these fluctuations to the stochasticity of the number of quanta contained in the hadron at the time of the interaction. For simplicity, we address the ideal case in which the hadron is an onium and investigate different kinematical regimes in the rapidity and onium size. We show that at large rapidity, the multiplicity distribution exhibits an exponential tail in the large-multiplicity region, which is qualitatively consistent with the proton-nucleus data. But interestingly enough, the exponential shape is determined by confinement.

  3. Ab initio calculation of the potential bubble nucleus 34Si

    NASA Astrophysics Data System (ADS)

    Duguet, T.; Somà, V.; Lecluse, S.; Barbieri, C.; Navrátil, P.

    2017-03-01

    Background: The possibility that an unconventional depletion (referred to as a "bubble") occurs in the center of the charge density distribution of certain nuclei due to a purely quantum mechanical effect has attracted theoretical and experimental attention in recent years. Based on a mean-field rationale, a correlation between the occurrence of such a semibubble and an anomalously weak splitting between low angular-momentum spin-orbit partners has been further conjectured. Energy density functional and valence-space shell model calculations have been performed to identify and characterize the best candidates, among which 34Si appears as a particularly interesting case. While the experimental determination of the charge density distribution of the unstable 34Si is currently out of reach, (d ,p ) experiments on this nucleus have been performed recently to test the correlation between the presence of a bubble and an anomalously weak 1 /2--3 /2- splitting in the spectrum of 35Si as compared to 37S. Purpose: We study the potential bubble structure of 34Si on the basis of the state-of-the-art ab initio self-consistent Green's function many-body method. Methods: We perform the first ab initio calculations of 34Si and 36S. In addition to binding energies, the first observables of interest are the charge density distribution and the charge root-mean-square radius for which experimental data exist in 36S. The next observable of interest is the low-lying spectroscopy of 35Si and 37S obtained from (d ,p ) experiments along with the spectroscopy of 33Al and 35P obtained from knock-out experiments. The interpretation in terms of the evolution of the underlying shell structure is also provided. The study is repeated using several chiral effective field theory Hamiltonians as a way to test the robustness of the results with respect to input internucleon interactions. The convergence of the results with respect to the truncation of the many-body expansion, i.e., with respect to

  4. Graphical imaging system for shifted spectrum in daughter nuclei of charged-current v-nucleus reactions

    NASA Astrophysics Data System (ADS)

    Sinatkas, J.; Kosmas, T. S.; Tsakstara, V.

    2015-09-01

    In this work, we improve the automated algorithm derived previously for drawing the quantum energy levels, in order to be efficient for plotting the theoretical spectra of the daughter nuclei in charged-current neutrino-nucleus reactions. Such calculated spectra need to be shifted so as the charged-current transition energies to be measured from the ground state of the daughter nucleus. The improvement involves the development of a computational code and graphical imaging system able to treat appropriately and as accurate as possible the energy-shifting which is different for the various multipole sets of nuclear states. The method is applied in the case of antineutrino-nucleus reaction which is of current experimental interest.

  5. MINER{nu}A, a Neutrino--Nucleus Interaction Experiment

    SciTech Connect

    Solano Salinas, C. J.; Chamorro, A.; Romero, C.

    2007-10-26

    With the fantastic results of KamLAND and SNO for neutrino physics, a new generation of neutrino experiments are being designed and build, specially to study the neutrino oscillations to resolve most of the incognita still we have in the neutrino physics. At FERMILAB we have the experiments MINOS and, in a near future, NO{nu}A, to study this kind of oscillations. One big problem these experiments will have is the lack of a good knowledge of the Physics of neutrino interactions with matter, and this will generate big systematic errors. MINER{nu}A, also at FERMILAB, will cover this space studying with high statistics and great precision the neutrino--nucleus interactions.

  6. Excited states of the 150Pm odd-odd nucleus

    NASA Astrophysics Data System (ADS)

    Bucurescu, D.; Drăgulescu, E.; Pascu, S.; Wirth, H.-F.; Filipescu, D.; Căta-Danil, G.; Căta-Danil, I.; Deleanu, D.; Eppinger, K.; Faestermann, T.; Ghiţă, D. G.; Glodariu, T.; Hertenberger, R.; Ivaşcu, M.; Krücken, R.; Mărginean, N.; Mărginean, R.; Mihai, C.; Negret, A.; Sava, T.; Stroe, L.; Wimmer, K.; Zamfir, N. V.

    2012-01-01

    The knowledge of excited states in the odd-odd 150Pm, completely unknown until recently, is important both for understanding double β decay of 150Nd and for nuclear structure studies in mass regions with a quantum phase transition. A large number of excited states have been determined for the first time in this nucleus by measuring spectra of the 152Sm(d,α) direct reaction at 25 MeV with the Munich Q3D spectrograph and by γ-ray spectroscopy with the (p,nγ) reaction at 7.1 MeV at the Bucharest tandem accelerator. Some of these levels correspond to peaks recently observed with the (3He,t) reaction at 140 MeV/u.

  7. The IMPORTance of the Nucleus during Flavivirus Replication

    PubMed Central

    Lopez-Denman, Adam J.; Mackenzie, Jason M.

    2017-01-01

    Flaviviruses are a large group of arboviruses of significant medical concern worldwide. With outbreaks a common occurrence, the need for efficient viral control is required more than ever. It is well understood that flaviviruses modulate the composition and structure of membranes in the cytoplasm that are crucial for efficient replication and evading immune detection. As the flavivirus genome consists of positive sense RNA, replication can occur wholly within the cytoplasm. What is becoming more evident is that some viral proteins also have the ability to translocate to the nucleus, with potential roles in replication and immune system perturbation. In this review, we discuss the current understanding of flavivirus nuclear localisation, and the function it has during flavivirus infection. We also describe—while closely related—the functional differences between similar viral proteins in their nuclear translocation. PMID:28106839

  8. Workshop on Analysis of Returned Comet Nucleus Samples

    NASA Astrophysics Data System (ADS)

    Chang, Sherwood

    This volume contains abstracts that have been accepted by the Program Committee for presentation at the Workshop on Analysis of Returned Comet Nucleus Samples, held in Milpitas, California, January 16-18, 1989. Conveners are Sherwood Chang (NASA Ames Research Center) and Larry Nyquist (NASA Johnson Space Center). Program Committee members are Thomas Ahrens (ex-officio; California Institute of Technology), Lou Allamandola (NASA Ames Research Center), David Blake (NASA Ames Research Center), Donald Brownlee (University of Washington, Seattle), Theodore E. Bunch (NASA Ames Research Center), Humberto Campins (Planetary Science Institute), Jeff Cuzzi (NASA Ames Research Center), Eberhard Griin (Max-Plank-Institut fiir Kemphysik), Martha Hanner (Jet Propulsion Laboratory), Alan Harris (Jet Propulsion Laboratory), John Kerrid-e (University of Califomia, Los Angeles), Yves Langevin (University of Paris), Gerhard Schwehm (ESTEC), and Paul Weissman (Jet Propulsion Laboratory). Logistics and administrative support for the workshop were provided by the Lunar and Planetary Institute Projects Office.

  9. Isoperiodic neuronal activity in suprachiasmatic nucleus of the rat

    NASA Technical Reports Server (NTRS)

    Miller, J. D.; Fuller, C. A.

    1992-01-01

    A subpopulation of neurons in the suprachiasmatic nucleus (SCN) is shown here to exhibit isoperiodic bursting activity. The period of discharge in these cells may be lengthened or the periodicity may be transiently disrupted by photic stimulation. It is suggested that many, if not all, of these cells are vasoactive intestinal polypeptide (VIP) neurons. It is shown that the ultradian periodicity of these cells, estimates of the VIP neuron population size in the SCN, effects of partial lesions on tau (period), and estimates of the phase stability of SCN-driven circadian rhythms are consistent with a strongly coupled, multioscillator model of circadian rhythmicity, in which the oscillator population constitutes a restricted subset of the SCN neuronal population.

  10. The subthalamic nucleus during decision-making with multiple alternatives.

    PubMed

    Keuken, Max C; Van Maanen, Leendert; Bogacz, Rafal; Schäfer, Andreas; Neumann, Jane; Turner, Robert; Forstmann, Birte U

    2015-10-01

    Several prominent neurocomputational models predict that an increase of choice alternatives is modulated by increased activity in the subthalamic nucleus (STN). In turn, increased STN activity allows prolonged accumulation of information. At the same time, areas in the medial frontal cortex such as the anterior cingulate cortex (ACC) and the pre-SMA are hypothesized to influence the information processing in the STN. This study set out to test concrete predictions of STN activity in multiple-alternative decision-making using a multimodal combination of 7 Tesla structural and functional Magnetic Resonance Imaging, and ancestral graph (AG) modeling. The results are in line with the predictions in that increased STN activity was found with an increasing amount of choice alternatives. In addition, our study shows that activity in the ACC is correlated with activity in the STN without directly modulating it. This result sheds new light on the information processing streams between medial frontal cortex and the basal ganglia.

  11. Intermuscular coherence in Parkinson's disease: effects of subthalamic nucleus stimulation.

    PubMed

    Marsden, J; Limousin-Dowsey, P; Fraix, V; Pollak, P; Odin, P; Brown, P

    2001-05-08

    It remains unclear how high frequency stimulation of the subthalamic nucleus (STN) improves parkinsonism. We hypothesized that stimulation may affect the organization of the cortical drive to voluntarily activated muscle. Normally this is characterized by oscillations at 15-30 Hz, manifest in coherence between muscles in the same frequency band. We therefore investigated the effects of STN stimulation on electromyographic (EMG) activity in co-contracting distal arm muscles in nine subjects with Parkinson's disease off drugs. Without stimulation, coherence between EMG signals was diminished at 15-30 Hz compared with nine controls. STN stimulation increased coherence in the 15-30 Hz band, so that it approached that in healthy subjects. The results suggest that STN stimulation facilitates the normal cortical drive to muscles.

  12. Synaptic mechanisms underlying cholinergic control of thalamic reticular nucleus neurons

    PubMed Central

    Beierlein, Michael

    2014-01-01

    Neuronal networks of the thalamus are the target of extensive cholinergic projections from the basal forebrain and the brainstem. Activation of these afferents can regulate neuronal excitability, transmitter release, and firing patterns in thalamic networks, thereby altering the flow of sensory information during distinct behavioural states. However, cholinergic regulation in the thalamus has been primarily examined by using receptor agonist and antagonist, which has precluded a detailed understanding of the spatiotemporal dynamics that govern cholinergic signalling under physiological conditions. This review summarizes recent studies on cholinergic synaptic transmission in the thalamic reticular nucleus (TRN), a brain structure intimately involved in the control of sensory processing and the generation of rhythmic activity in the thalamocortical system. This work has shown that acetylcholine (ACh) released from individual axons can rapidly and reliably activate both pre- and postsynaptic cholinergic receptors, thereby controlling TRN neuronal activity with high spatiotemporal precision. PMID:24973413

  13. Serotonin neurons in the dorsal raphe nucleus encode reward signals

    PubMed Central

    Li, Yi; Zhong, Weixin; Wang, Daqing; Feng, Qiru; Liu, Zhixiang; Zhou, Jingfeng; Jia, Chunying; Hu, Fei; Zeng, Jiawei; Guo, Qingchun; Fu, Ling; Luo, Minmin

    2016-01-01

    The dorsal raphe nucleus (DRN) is involved in organizing reward-related behaviours; however, it remains unclear how genetically defined neurons in the DRN of a freely behaving animal respond to various natural rewards. Here we addressed this question using fibre photometry and single-unit recording from serotonin (5-HT) neurons and GABA neurons in the DRN of behaving mice. Rewards including sucrose, food, sex and social interaction rapidly activate 5-HT neurons, but aversive stimuli including quinine and footshock do not. Both expected and unexpected rewards activate 5-HT neurons. After mice learn to wait for sucrose delivery, most 5-HT neurons fire tonically during waiting and then phasically on reward acquisition. Finally, GABA neurons are activated by aversive stimuli but inhibited when mice seek rewards. Thus, DRN 5-HT neurons positively encode a wide range of reward signals during anticipatory and consummatory phases of reward responses. Moreover, GABA neurons play a complementary role in reward processing. PMID:26818705

  14. Reward and reinforcement activity in the nucleus accumbens during learning

    PubMed Central

    Gale, John T.; Shields, Donald C.; Ishizawa, Yumiko; Eskandar, Emad N.

    2014-01-01

    The nucleus accumbens core (NAcc) has been implicated in learning associations between sensory cues and profitable motor responses. However, the precise mechanisms that underlie these functions remain unclear. We recorded single-neuron activity from the NAcc of primates trained to perform a visual-motor associative learning task. During learning, we found two distinct classes of NAcc neurons. The first class demonstrated progressive increases in firing rates at the go-cue, feedback/tone and reward epochs of the task, as novel associations were learned. This suggests that these neurons may play a role in the exploitation of rewarding behaviors. In contrast, the second class exhibited attenuated firing rates, but only at the reward epoch of the task. These findings suggest that some NAcc neurons play a role in reward-based reinforcement during learning. PMID:24765069

  15. Subthalamic nucleus stimulation reverses mediofrontal influence over decision threshold.

    PubMed

    Cavanagh, James F; Wiecki, Thomas V; Cohen, Michael X; Figueroa, Christina M; Samanta, Johan; Sherman, Scott J; Frank, Michael J

    2011-09-25

    It takes effort and time to tame one's impulses. Although medial prefrontal cortex (mPFC) is broadly implicated in effortful control over behavior, the subthalamic nucleus (STN) is specifically thought to contribute by acting as a brake on cortico-striatal function during decision conflict, buying time until the right decision can be made. Using the drift diffusion model of decision making, we found that trial-to-trial increases in mPFC activity (EEG theta power, 4-8 Hz) were related to an increased threshold for evidence accumulation (decision threshold) as a function of conflict. Deep brain stimulation of the STN in individuals with Parkinson's disease reversed this relationship, resulting in impulsive choice. In addition, intracranial recordings of the STN area revealed increased activity (2.5-5 Hz) during these same high-conflict decisions. Activity in these slow frequency bands may reflect a neural substrate for cortico-basal ganglia communication regulating decision processes.

  16. Glutamatergic signaling by mesolimbic dopamine neurons in the nucleus accumbens.

    PubMed

    Tecuapetla, Fatuel; Patel, Jyoti C; Xenias, Harry; English, Daniel; Tadros, Ibrahim; Shah, Fulva; Berlin, Joshua; Deisseroth, Karl; Rice, Margaret E; Tepper, James M; Koos, Tibor

    2010-05-19

    Recent evidence suggests the intriguing possibility that midbrain dopaminergic (DAergic) neurons may use fast glutamatergic transmission to communicate with their postsynaptic targets. Because of technical limitations, direct demonstration of the existence of this signaling mechanism has been limited to experiments using cell culture preparations that often alter neuronal function including neurotransmitter phenotype. Consequently, it remains uncertain whether glutamatergic signaling between DAergic neurons and their postsynaptic targets exists under physiological conditions. Here, using an optogenetic approach, we provide the first conclusive demonstration that mesolimbic DAergic neurons in mice release glutamate and elicit excitatory postsynaptic responses in projection neurons of the nucleus accumbens. In addition, we describe the properties of the postsynaptic glutamatergic responses of these neurons during experimentally evoked burst firing of DAergic axons that reproduce the reward-related phasic population activity of the mesolimbic projection. These observations indicate that, in addition to DAergic mechanisms, mesolimbic reward signaling may involve glutamatergic transmission.

  17. Glutamatergic Signaling by Mesolimbic Dopamine Neurons in the Nucleus Accumbens

    PubMed Central

    Tecuapetla, Fatuel; Patel, Jyoti C.; Xenias, Harry; English, Daniel; Tadros, Ibrahim; Shah, Fulva; Berlin, Joshua; Deisseroth, Karl; Rice, Margaret E.; Tepper, James M.

    2010-01-01

    Recent evidence suggests the intriguing possibility that midbrain dopaminergic (DAergic) neurons may use fast glutamatergic transmission to communicate with their postsynaptic targets. Because of technical limitations, direct demonstration of the existence of this signaling mechanism has been limited to experiments using cell culture preparations that often alter neuronal function including neurotransmitter phenotype. Consequently, it remains uncertain whether glutamatergic signaling between DAergic neurons and their postsynaptic targets exists under physiological conditions. Here, using an optogenetic approach, we provide the first conclusive demonstration that mesolimbic DAergic neurons in mice release glutamate and elicit excitatory postsynaptic responses in projection neurons of the nucleus accumbens. In addition, we describe the properties of the postsynaptic glutamatergic responses of these neurons during experimentally evoked burst firing of DAergic axons that reproduce the reward-related phasic population activity of the mesolimbic projection. These observations indicate that, in addition to DAergic mechanisms, mesolimbic reward signaling may involve glutamatergic transmission. PMID:20484653

  18. Traces of the Θ+ Pentaquark in K+-Nucleus Dynamics

    NASA Astrophysics Data System (ADS)

    Gal, A.; Friedman, E.

    2005-02-01

    Long-standing anomalies in K+-nucleus integral cross sections could be resolved by extending the impulse-approximation tρ optical-potential framework to incorporate K+ absorption on pairs of nucleons. Substantially improved fits to the data at plab˜500 700 MeV/c are obtained. An upper bound on the absorption cross section per nucleon is derived, σabs(K+)/A˜3.5 mb. We conjecture that the underlying microscopic absorption process is K+nN→Θ+N, where Θ+(1540) is the newly discovered exotic Y=2, I=0, Z=1 pentaquark baryon, and estimate that σ(K+d→Θ+p) is a fraction of millibarn. Comments are made on Θ+ production reactions on nuclei.

  19. Plastid-nucleus communication involves calcium-modulated MAPK signalling

    PubMed Central

    Guo, Hailong; Feng, Peiqiang; Chi, Wei; Sun, Xuwu; Xu, Xiumei; Li, Yuan; Ren, Dongtao; Lu, Congming; David Rochaix, Jean; Leister, Dario; Zhang, Lixin

    2016-01-01

    Chloroplast retrograde signals play important roles in coordinating the plastid and nuclear gene expression and are critical for proper chloroplast biogenesis and for maintaining optimal chloroplast functions in response to environmental changes in plants. Until now, the signals and the mechanisms for retrograde signalling remain poorly understood. Here we identify factors that allow the nucleus to perceive stress conditions in the chloroplast and to respond accordingly by inducing or repressing specific nuclear genes encoding plastid proteins. We show that ABI4, which is known to repress the LHCB genes during retrograde signalling, is activated through phosphorylation by the MAP kinases MPK3/MPK6 and the activity of these kinases is regulated through 14-3-3ω-mediated Ca2+-dependent scaffolding depending on the chloroplast calcium sensor protein CAS. These findings uncover an additional mechanism in which chloroplast-modulated Ca2+ signalling controls the MAPK pathway for the activation of critical components of the retrograde signalling chain. PMID:27399341

  20. Quantum Monte Carlo Calculations of Nucleon-Nucleus Scattering

    NASA Astrophysics Data System (ADS)

    Wiringa, R. B.; Nollett, Kenneth M.; Pieper, Steven C.; Brida, I.

    2009-10-01

    We report recent quantum Monte Carlo (variational and Green's function) calculations of elastic nucleon-nucleus scattering. We are adding the cases of proton-^4He, neutron-^3H and proton-^3He scattering to a previous GFMC study of neutron-^4He scattering [1]. To do this requires generalizing our methods to include long-range Coulomb forces and to treat coupled channels. The two four-body cases can be compared to other accurate four-body calculational methods such as the AGS equations and hyperspherical harmonic expansions. We will present results for the Argonne v18 interaction alone and with Urbana and Illinois three-nucleon potentials. [4pt] [1] K.M. Nollett, S. C. Pieper, R.B. Wiringa, J. Carlson, and G.M. Hale, Phys. Rev. Lett. 99, 022502 (2007)

  1. Semi-inclusive charged-current neutrino-nucleus reactions

    SciTech Connect

    Moreno, O.; Donnelly, T. W.; Van Orden, J. W.; Ford, W. P.

    2014-07-17

    The general, universal formalism for semi-inclusive charged-current (anti)neutrino-nucleus reactions is given for studies of any hadronic system, namely, either nuclei or the nucleon itself. The detailed developments are presented with the former in mind and are further specialized to cases where the final-state charged lepton and an ejected nucleon are presumed to be detected. General kinematics for such processes are summarized and then explicit expressions are developed for the leptonic and hadronic tensors involved and for the corresponding responses according to the usual charge, longitudinal and transverse projections, keeping finite the masses of all particles involved. In the case of the hadronic responses, general symmetry principles are invoked to determine which contributions can occur. As a result, the general leptonic-hadronic tensor contraction is given as well as the cross section for the process.

  2. Semi-inclusive charged-current neutrino-nucleus reactions

    DOE PAGES

    Moreno, O.; Donnelly, T. W.; Van Orden, J. W.; ...

    2014-07-17

    The general, universal formalism for semi-inclusive charged-current (anti)neutrino-nucleus reactions is given for studies of any hadronic system, namely, either nuclei or the nucleon itself. The detailed developments are presented with the former in mind and are further specialized to cases where the final-state charged lepton and an ejected nucleon are presumed to be detected. General kinematics for such processes are summarized and then explicit expressions are developed for the leptonic and hadronic tensors involved and for the corresponding responses according to the usual charge, longitudinal and transverse projections, keeping finite the masses of all particles involved. In the case ofmore » the hadronic responses, general symmetry principles are invoked to determine which contributions can occur. As a result, the general leptonic-hadronic tensor contraction is given as well as the cross section for the process.« less

  3. Attention modulates responses in the human lateral geniculate nucleus.

    PubMed

    O'Connor, Daniel H; Fukui, Miki M; Pinsk, Mark A; Kastner, Sabine

    2002-11-01

    Attentional mechanisms are important for selecting relevant information and filtering out irrelevant information from cluttered visual scenes. Selective attention has previously been shown to affect neural activity in both extrastriate and striate visual cortex. Here, evidence from functional brain imaging shows that attentional response modulation is not confined to cortical processing, but can occur as early as the thalamic level. We found that attention modulated neural activity in the human lateral geniculate nucleus (LGN) in several ways: it enhanced neural responses to attended stimuli, attenuated responses to ignored stimuli and increased baseline activity in the absence of visual stimulation. The LGN, traditionally viewed as the gateway to visual cortex, may also serve as a 'gatekeeper' in controlling attentional response gain.

  4. Connectivity of the pedunculopontine nucleus in parkinsonian freezing of gait.

    PubMed

    Schweder, Patrick M; Hansen, Peter C; Green, Alex L; Quaghebeur, Gerardine; Stein, John; Aziz, Tipu Z

    2010-10-06

    Parkinson's disease (PD) may involve sudden unintended arrests in gait or failure to initiate gait, known as gait freezing. Deep brain stimulation of the pedunculopontine nucleus (PPN) has been found to be an effective therapy for this phenomenon. In this study, we characterized the connectivity of the PPN freezing of gait (FOG) patients, compared with non-FOG PD and healthy controls using diffusion tensor imaging techniques. Differences in PPN connectivity profiles of the study groups were shown in the cerebellum and pons. The PPN showed connectivity with the cerebellum in controls and non-FOG PD. FOG patients showed absence of cerebellar connectivity, and increased visibility of the decussation of corticopontine fibres in the anterior pons. The findings suggest that corticopontine projections, which cross at the pons are increased in gait freezing, highlighting the importance and role of corticopontine-cerebellar pathways in the pathophysiology of this phenomenon.

  5. The nucleus accumbens: an interface between cognition, emotion, and action.

    PubMed

    Floresco, Stan B

    2015-01-03

    Nearly 40 years of research on the function of the nucleus accumbens (NAc) has provided a wealth of information on its contributions to behavior but has also yielded controversies and misconceptions regarding these functions. A primary tenet of this review is that, rather than serving as a "reward" center, the NAc plays a key role in action selection, integrating cognitive and affective information processed by frontal and temporal lobe regions to augment the efficiency and vigor of appetitively or aversively motivated behaviors. Its involvement in these functions is most prominent when the appropriate course of action is ambiguous, uncertain, laden with distractors, or in a state of flux. To this end, different subregions of the NAc play dissociable roles in refining action selection, promoting approach toward motivationally relevant stimuli, suppressing inappropriate actions so that goals may be obtained more efficiently, and encoding action outcomes that guide the direction of subsequent ones.

  6. Input/output properties of the lateral vestibular nucleus

    NASA Technical Reports Server (NTRS)

    Boyle, R.; Bush, G.; Ehsanian, R.

    2004-01-01

    This article is a review of work in three species, squirrel monkey, cat, and rat studying the inputs and outputs from the lateral vestibular nucleus (LVN). Different electrophysiological shock paradigms were used to determine the synaptic inputs derived from thick to thin diameter vestibular nerve afferents. Angular and linear mechanical stimulations were used to activate and study the combined and individual contribution of inner ear organs and neck afferents. The spatio-temporal properties of LVN neurons in the decerebrated rat were studied in response to dynamic acceleration inputs using sinusoidal linear translation in the horizontal head plane. Outputs were evaluated using antidromic identification techniques and identified LVN neurons were intracellularly injected with biocytin and their morphology studied.

  7. Breakup reaction study of the Brunnian nucleus {sup 10}C

    SciTech Connect

    Curtis, N.; Ashwood, N. I.; Clarke, N. M.; Freer, M.; Haigh, P. J.; Ziman, V.; Achouri, N. L.; Laurent, B.; Orr, N. A.; Bohlen, H. G.; Catford, W. N.; Patterson, N. P.; Thomas, J. S.; Soic, N.

    2008-02-15

    The structure and 2{alpha}+2p breakup of {sup 10}C, the only known Brunnian nucleus, has been studied at 33.3 MeV/nucleon. The breakup kinematics were used to reconstruct the {sup 10}C {yields} {sup 9}B +p,{sup 9}B {yields} {sup 8}Be +p,{sup 8}Be {yields}{alpha}+{alpha} and {sup 10}C {yields} {sup 6}Be +{alpha},{sup 6}Be {yields} {sup 5}Li +p,{sup 5}Li {yields}{alpha}+p decay paths. Proton emission was seen to be favored. The decay of excited states at E{sub x}=4.20,5.31, and 6.74 MeV was observed. The previously unobserved state at 4.20 MeV may correspond to a J{sup {pi}}=0{sup +}{alpha}+2p+{alpha} cluster structure.

  8. Pseudotumor of the omentum with a fishbone nucleus.

    PubMed

    Yamamoto, Takatsugu; Hirohashi, Kazuhiro; Iwasaki, Hiroto; Kubo, Shoji; Tanaka, Yoshinori; Yamasaki, Keiichi; Koh, Masae; Uenishi, Takahiro; Ogawa, Masao; Sakabe, Katsu; Tanaka, Shogo; Shuto, Taichi; Tanaka, Hiromu

    2007-04-01

    A 23-year-old Japanese man was admitted with a chief complaint of abdominal pain. He was previously healthy, and his past medical history was unremarkable. Local tenderness and rebound tenderness at McBurney's point were elicited. Abdominal roentgenography was non-diagnostic. Ultrasonography and computed tomography showed a tumor with a central core. Based on a diagnosis of appendicitis with omental inflammation or an omental tumor, laparotomy performed. Intraoperatively, no site of gastrointestinal perforation was detected; however, a 5-cm omental granuloma was identified that proved to have a fishbone nucleus on pathological examination. The postoperative course was uneventful, and upper gastrointestinal endoscopy and barium enema were unremarkable. A large solitary omental pseudotumor is rare, and the clinical course in this case was atypical compared with the usual course of intestinal perforation by a foreign body and formation of an intra-abdominal granuloma.

  9. Highlight on the dynamic organization of the nucleus

    PubMed Central

    2017-01-01

    ABSTRACT The last decade has seen rapid advances in our understanding of the proteins of the nuclear envelope, which have multiple roles including positioning the nucleus, maintaining its structural organization, and in events ranging from mitosis and meiosis to chromatin positioning and gene expression. Diverse new and stimulating results relating to nuclear organization and genome function from across kingdoms were presented in a session stream entitled “Dynamic Organization of the Nucleus” at this year's Society of Experimental Biology (SEB) meeting in Brighton, UK (July 2016). This was the first session stream run by the Nuclear Dynamics Special Interest Group, which was organized by David Evans, Katja Graumann (both Oxford Brookes University, UK) and Iris Meier (Ohio State University, USA). The session featured presentations on areas relating to nuclear organization across kingdoms including the nuclear envelope, chromatin organization, and genome function. PMID:27715428

  10. Systematics of the release of residual nuclei from relativistic nucleus-nucleus interactions

    NASA Technical Reports Server (NTRS)

    Binns, W. R.; Israel, M. H.; Klarmann, J.; Garrard, T. L.; Kertzmann, M. P.

    1987-01-01

    Relativistic nuclei of krypton, xenon, holmium, and gold, accelerated in a partially stripped state to a maximum rigidity of about 5.6 GeV, interacting with targets of aluminum, carbon, and polyethylene are examined. For each projectile and target combination, determinations are made for the total and partial charge changing cross sections for the production of lighter fragments. From these measurements, a new representation of the dependence of the total charge changing cross sections on beam and target charge is developed. Simple representations of the variation of the partial cross sections were identified with the charge of the produced fragments and shown to be dependent on the charge and energy of the beam. The fission of gold nuclei at high energies in these various targets has also been studied.

  11. Definite evidence of the Landau-Zener transition in nucleus-nucleus collisions

    SciTech Connect

    Imanishi, B.; von Oertzen, W.; Voit, H.

    1987-01-01

    It is shown that the Landau-Zener transition mechanism due to the formation of molecular orbitals of the active neutron exists in the inelastic scattering /sup 13/C(/sup 12/C, /sup 12/C)/sup 13/C/sup */ (3.086 MeV, (1/2)/sup +/). The evidence stems from characteristic changes of the angular distributions observed as a function of the incident energy.

  12. Systematic failure of static nucleus-nucleus potential to explore sub-barrier fusion dynamics

    NASA Astrophysics Data System (ADS)

    Singh Gautam, Manjeet

    2015-05-01

    This paper addresses the validity of the static Woods-Saxon potential and the energy dependent Woods-Saxon potential (EDWSP) for description of sub-barrier fusion dynamics. The low lying surface vibrations of colliding nuclei and neutron transfer channels are found to be major factors responsible for fusion enhancement at sub-barrier energies. Theoretical calculations based upon the static Woods-Saxon potential obtained using the one-dimensional Wong formula fail to explain the energy dependence of the sub-barrier fusion cross-section of {}2040C{}{}a+{}2246,48,50T{}{}i systems. The role of inelastic surface vibrations is properly entertained within the context of coupled channel calculations performed using the CCFULL code. However, the EDWSP model, in conjunction with the one-dimensional Wong formula, accurately explains the sub-barrier fusion enhancement of {}2040C{}{}a+{}2246,48,50T{}{}i systems and simulates the influence of nuclear structure degrees of freedom, such as the inelastic surface vibrational states of colliding pairs. In EDWSP model calculations, a wide range of diffuseness parameters, ranging from a=0.96 fm to a=0.85 fm, which is much larger than a value ≤ft( a=0.65 fm \\right) extracted from the elastic scattering data, is required to bring the observed fusion enhancement.

  13. Pedunculopontine nucleus microelectrode recordings in movement disorder patients.

    PubMed

    Weinberger, Moran; Hamani, Clement; Hutchison, William D; Moro, Elena; Lozano, Andres M; Dostrovsky, Jonathan O

    2008-06-01

    The pedunculopontine nucleus (PPN) lies within the brainstem reticular formation and is involved in the motor control of gait and posture. Interest has focused recently on the PPN as a target for implantation of chronic deep brain stimulation (DBS) electrodes for Parkinson's disease (PD) and progressive supranuclear palsy (PSP) therapy. The aim of this study was to examine the neurophysiology of the human PPN region and to identify neurophysiological landmarks that may aid the proper placement of DBS electrodes in the nucleus for the treatment of PD and PSP. Neuronal firing and local field potentials were recorded simultaneously from two independently driven microelectrodes during stereotactic neurosurgery for implantation of a unilateral DBS electrode in the PPN in five PD patients and two PSP patients. Within the PPN region, the majority (57%) of the neurons fired randomly while about 21% of the neurons exhibited 'bursty' firing. In addition, 21% of the neurons had a long action potential duration and significantly lower firing rate suggesting they were cholinergic neurons. A change in firing rate produced by passive and/or active contralateral limb movement was observed in 38% of the neurons that were tested in the PPN region. Interestingly, oscillatory local field potential activity in the beta frequency range ( approximately 25 Hz) was also observed in the PPN region. These electrophysiological characteristics of the PPN region provide further support for the proposed role of this region in motor control. It remains to be seen to what extent the physiological characteristics of the neurons and the stimulation-evoked effects will permit reliable identification of PPN and determination of the optimal target for DBS therapy.

  14. Cholinergic mechanisms of high-frequency stimulation in entopeduncular nucleus

    PubMed Central

    Luo, Feng

    2015-01-01

    Chronic, high-frequency (>100 Hz) electrical stimulation, known as deep brain stimulation (DBS), of the internal segment of the globus pallidus (GPi) is a highly effective therapy for Parkinson's disease (PD) and dystonia. Despite some understanding of how it works acutely in PD models, there remain questions about its mechanisms of action. Several hypotheses have been proposed, such as depolarization blockade, activation of inhibitory synapses, depletion of neurotransmitters, and/or disruption/alteration of network oscillations. In this study we investigated the cellular mechanisms of high-frequency stimulation (HFS) in entopeduncular nucleus (EP; rat equivalent of GPi) neurons using whole cell patch-clamp recordings. We found that HFS applied inside the EP nucleus induced a prolonged afterdepolarization that was dependent on stimulation frequency, pulse duration, and current amplitude. The high frequencies (>100 Hz) and pulse widths (>0.15 ms) used clinically for dystonia DBS could reliably induce these afterdepolarizations, which persisted under blockade of ionotropic glutamate (kynurenic acid, 2 mM), GABAA (picrotoxin, 50 μM), GABAB (CGP 55845, 1 μM), and acetylcholine nicotinic receptors (DHβE, 2 μM). However, this effect was blocked by atropine (2 μM; nonselective muscarinic antagonist) or tetrodotoxin (0.5 μM). Finally, the muscarinic-dependent afterdepolarizations were sensitive to Ca2+-sensitive nonspecific cationic (CAN) channel blockade. Hence, these data suggest that muscarinic receptor activation during HFS can lead to feedforward excitation through the opening of CAN channels. This study for the first time describes a cholinergic mechanism of HFS in EP neurons and provides new insight into the underlying mechanisms of DBS. PMID:26334006

  15. Reversible neurotoxicity of kanamycin on dorsal cochlear nucleus.

    PubMed

    Fan, Guo-Run; Yin, Ze-Deng; Sun, Yu; Chen, Sen; Zhang, Wen-Juan; Huang, Xiang; Kong, Wei-Jia; Zhang, Hong-Lian

    2013-03-28

    The time course of aminoglycoside neurotoxic effect on cochlear nucleus is still obscure. We examined dynamic pathological changes of dorsal cochlear nucleus (DCN) and investigated whether apoptosis or autophagy was upregulated in the neurotoxic course of kanamycin on DCN after kanamycin treatment. Rats were treated with kanamycin sulfate/kg/day at a dose of 500mg by subcutaneous injection for 10 days. Dynamic pathological changes, neuron density and neuron apoptosis of the DCN were examined at 1, 7, 14, 28, 56, 70 and 140 days after kanamycin treatment. The expressions of JNK1, DAPK2, Bcl-2, p-Bcl-2, Caspase-3, LC3B and Beclin-1 were also detected. Under transmission electron microscopy, the mitochondrial swelling and focal vacuoles as well as endoplasmic reticulum dilation were progressively aggravated from 1 day to 14 days, and gradually recovered from 28 days to 140 days. Meanwhile, both autophagosomes and autolysosomes were increased from 1 day to 56 days. Only few neurons were positive to the TUNEL staining. Moreover, neither the expressions of caspase-3 and DAPK2 nor neurons density of DCN changed significantly. LC3-II was drastically increased at 7 days. Beclin-1 was upgraded at 1 and 7 days. P-Bcl-2 increased at 1, 7, 14 and 28 days. JNK1 increased at 7 days, and Bcl-2 was downgraded at 140 days. LC3-B positive neurons were increased at 1, 7 and 14 days. These data demonstrated that the neurons damage of the DCN caused by kanamycin was reversible and autophagy was upregulated in the neurotoxic course of kanamycin on DCN through JNK1-mediated phosphorylation of Bcl-2 pathway.

  16. The dolphin cochlear nucleus: topography, histology and functional implications.

    PubMed

    Malkemper, E P; Oelschläger, H H A; Huggenberger, S

    2012-02-01

    Despite the outstanding auditory capabilities of dolphins, there is only limited information available on the cytology of the auditory brain stem nuclei in these animals. Here, we investigated the cochlear nuclei (CN) of five brains of common dolphins (Delphinus delphis) and La Plata dolphins (Pontoporia blainvillei) using cell and fiber stain microslide series representing the three main anatomical planes. In general, the CN in dolphins comprise the same set of subnuclei as in other mammals. However, the volume ratio of the dorsal cochlear nucleus (DCN) in relation to the ventral cochlear nucleus (VCN) of dolphins represents a minimum among the mammals examined so far. Because, for example, in cats the DCN is necessary for reflexive orientation of the head and pinnae towards a sound source, the massive restrictions in head movability in dolphins and the absence of outer ears may be correlated with the reduction of the DCN. Moreover, the same set of main neuron types were found in the dolphin CN as in other mammals, including octopus and multipolar cells. Because the latter two types of neurons are thought to be involved in the recognition of complex sounds, including speech, we suggest that, in dolphins, they may be involved in the processing of their communication signals. Comparison of the toothed whale species studied here revealed that large spherical cells were present in the La Plata dolphin but absent in the common dolphin. These neurons are known to be engaged in the processing of low-frequency sounds in terrestrial mammals. Accordingly, in the common dolphin, the absence of large spherical cells seems to be correlated with a shift of its auditory spectrum into the high-frequency range above 20 kHz. The existence of large spherical cells in the VCN of the La Plata dolphin, however, is enigmatic asthis species uses frequencies around 130 kHz.

  17. The ascending projection of the nucleus of the lateral descending trigeminal tract: a nucleus in the infrared system of the rattlesnake, Crotalus viridis

    SciTech Connect

    Stanford, L.R.; Schroeder, D.M.; Hartline, P.H.

    1981-01-01

    The efferent projections of the nucleus of the lateral descending trigeminal tract (LTTD) in the rattlesnake (Crotalus viridis) were studied by anterograde tracing techniques. The LTTD, a brainstem trigeminal nucleus, is the sole projection site of the infrared-sensitive trigeminal fibers that innervate the pit organs in these snakes. The efferent fibers exit from the ventromedial edge of the LTTD and course medially and caudally toward the central grey area of the medulla. Upon reaching the central region of the medulla these fibers turn and move laterally and rostrally, eventually forming a tract on the ventrolateral surface of the brainstem. Embedded in this tract and slightly overlapping the LTTD in the rostrocaudal axis, is a population of large (20-45 micrometer) multipolar neurons that forms the nucleus reticularis caloris. Heavy terminal and preterminal degeneration in this area indicates that many of the efferent fibers of the LTTD terminate in this nucleus. A small bundle of degenerating fibers turn dorsally from the ventrolateral tract and ascend to terminate in a nucleus associated with the cerebellum, the lateral tegmental nucleus. No projection was found to any other nuclei or areas in the brain. This study demonstrates that the infrared-sensitive snakes, along with developing peripheral specializations (the pit organs), have developed specialized nuclei to handle this additional sensory information. The direct projection from the LTTD to the nucleus reticularis caloris provides a pathway linking the infrared-sensitive neurons of the LTTD with neurons of the same modality in the optic tectum. The second LTTD projection, to the lateral tegmental nucleus, suggests a connection between the infrared system and the cerebellum in these animals.

  18. Effects of maternal separation and methamphetamine exposure on protein expression in the nucleus accumbens shell and core.

    PubMed

    Dimatelis, J J; Russell, V A; Stein, D J; Daniels, W M

    2012-09-01

    Early life adversity has been suggested to predispose an individual to later drug abuse. The core and shell sub-regions of the nucleus accumbens are differentially affected by both stressors and methamphetamine. This study aimed to characterize and quantify methamphetamine-induced protein expression in the shell and core of the nucleus accumbens in animals exposed to maternal separation during early development. Isobaric tagging (iTRAQ) which enables simultaneous identification and quantification of peptides with tandem mass spectrometry (MS/MS) was used. We found that maternal separation altered more proteins involved in structure and redox regulation in the shell than in the core of the nucleus accumbens, and that maternal separation and methamphetamine had differential effects on signaling proteins in the shell and core. Compared to maternal separation or methamphetamine alone, the maternal separation/methamphetamine combination altered more proteins involved in energy metabolism, redox regulatory processes and neurotrophic proteins. Methamphetamine treatment of rats subjected to maternal separation caused a reduction of cytoskeletal proteins in the shell and altered cytoskeletal, signaling, energy metabolism and redox proteins in the core. Comparison of maternal separation/methamphetamine to methamphetamine alone resulted in decreased cytoskeletal proteins in both the shell and core and increased neurotrophic proteins in the core. This study confirms that both early life stress and methamphetamine differentially affect the shell and core of the nucleus accumbens and demonstrates that the combination of early life adversity and later methamphetamine use results in more proteins being affected in the nucleus accumbens than either treatment alone.

  19. NPY and VGF Immunoreactivity Increased in the Arcuate Nucleus, but Decreased in the Nucleus of the Tractus Solitarius, of Type-II Diabetic Patients

    PubMed Central

    Saderi, Nadia; Salgado-Delgado, Roberto; Avendaño-Pradel, Rafael; Basualdo, Maria del Carmen; Ferri, Gian-Luca; Chávez-Macías, Laura; Escobar, Carolina; Buijs, Ruud M.

    2012-01-01

    Ample animal studies demonstrate that neuropeptides NPY and α-MSH expressed in Arcuate Nucleus and Nucleus of the Tractus Solitarius, modulate glucose homeostasis and food intake. In contrast is the absence of data validating these observations for human disease. Here we compare the post mortem immunoreactivity of the metabolic neuropeptides NPY, αMSH and VGF in the infundibular nucleus, and brainstem of 11 type-2 diabetic and 11 non-diabetic individuals. α-MSH, NPY and tyrosine hydroxylase in human brain are localized in the same areas as in rodent brain. The similar distribution of NPY, α-MSH and VGF indicated that these neurons in the human brain may share similar functionality as in the rodent brain. The number of NPY and VGF immuno positive cells was increased in the infundibular nucleus of diabetic subjects in comparison to non-diabetic controls. In contrast, NPY and VGF were down regulated in the Nucleus of the Tractus Solitarius of diabetic patients. These results suggest an activation of NPY producing neurons in the arcuate nucleus, which, according to animal experimental studies, is related to a catabolic state and might be the basis for increased hepatic glucose production in type-2 diabetes. PMID:22808091

  20. Research Resource: Gene Profiling of G Protein–Coupled Receptors in the Arcuate Nucleus of the Female

    PubMed Central

    Fang, Yuan; Zhang, Chunguang; Nestor, Casey C.; Mao, Peizhong; Kelly, Martin J.

    2014-01-01

    The hypothalamic arcuate nucleus controls many critical homeostatic functions including energy homeostasis, reproduction, and motivated behavior. Although G protein–coupled receptors (GPCRs) are involved in the regulation of these functions, relatively few of the GPCRs have been identified specifically within the arcuate nucleus. Here, using TaqMan low-density arrays we quantified the mRNA expression of nonolfactory GPCRs in mouse arcuate nucleus. An unprecedented number of GPCRs (total of 292) were found to be expressed, of which 183 were known and 109 were orphan GPCRs. The known GPCR genes expressed were classified into several functional clusters including hormone/neurotransmitter, growth factor, angiogenesis and vasoactivity, inflammation and immune system, and lipid messenger receptors. The plethora of orphan genes expressed in the arcuate nucleus were classified into 5 structure-related classes including class A (rhodopsin-like), class B (adhesion), class C (other GPCRs), nonsignaling 7-transmembrane chemokine-binding proteins, and other 7-transmembrane proteins. Therefore, for the first time, we provide a quantitative estimate of the numerous GPCRs expressed in the hypothalamic arcuate nucleus. Finally, as proof of principle, we documented the expression and function of one of these receptor genes, the glucagon-like peptide 1 receptor (Glp1r), which was highly expressed in the arcuate nucleus. Single-cell RT-PCR revealed that Glp1r mRNA was localized in proopiomelanocortin neurons, and using whole-cell recording we found that the glucagon-like peptide 1-selective agonist exendin-4 robustly excited proopiomelanocortin neurons. Thus, the quantitative GPCR data emphasize the complexity of the hypothalamic arcuate nucleus and furthermore provide a valuable resource for future neuroendocrine/endocrine-related experiments. PMID:24933249

  1. A triplet of differently shaped spin-zero states in the atomic nucleus 186Pb

    PubMed

    Andreyev; Huyse; Van Duppen P; Weissman; Ackermann; Gerl; Hessberger; Hofmann; Kleinbohl; Munzenberg; Reshitko; Schlegel; Schaffner; Cagarda; Matos; Saro; Keenan; Moore; O'Leary; Page; Taylor; Kettunen; Leino; Lavrentiev; Wyss; Heyde

    2000-05-25

    Understanding the fundamental excitations of many-fermion systems is of significant current interest. In atomic nuclei with even numbers of neutrons and protons, the low-lying excitation spectrum is generally formed by nucleon pair breaking and nuclear vibrations or rotations. However, for certain numbers of protons and neutrons, a subtle rearrangement of only a few nucleons among the orbitals at the Fermi surface can result in a different elementary mode: a macroscopic shape change. The first experimental evidence for this phenomenon came from the observation of shape coexistence in 16O (ref. 4). Other unexpected examples came with the discovery of fission isomers and super-deformed nuclei. Here we find experimentally that the lowest three states in the energy spectrum of the neutron deficient nucleus 186Pb are spherical, oblate and prolate. The states are populated by the alpha-decay of a parent nucleus; to identify them, we combine knowledge of the particular features of this decay with sensitive measurement techniques (a highly efficient velocity filters with strong background reduction, and an extremely selective recoil-alpha-electron coincidence tagging methods). The existence of this apparently unique shape triplet is permitted only by the specific conditions that are met around this particular nucleus.

  2. Purinergic signalling contributes to chemoreception in the retrotrapezoid nucleus but not the nucleus of the solitary tract or medullary raphe

    PubMed Central

    Sobrinho, Cleyton R; Wenker, Ian C; Poss, Erin M; Takakura, Ana C; Moreira, Thiago S; Mulkey, Daniel K

    2014-01-01

    Several brain regions are thought to function as important sites of chemoreception including the nucleus of the solitary tract (NTS), medullary raphe and retrotrapezoid nucleus (RTN). In the RTN, mechanisms of chemoreception involve direct H+-mediated activation of chemosensitive neurons and indirect modulation of chemosensitive neurons by purinergic signalling. Evidence suggests that RTN astrocytes are the source of CO2-evoked ATP release. However, it is not clear whether purinergic signalling also influences CO2/H+ responsiveness of other putative chemoreceptors. The goals of this study are to determine if CO2/H+-sensitive neurons in the NTS and medullary raphe respond to ATP, and whether purinergic signalling in these regions influences CO2 responsiveness in vitro and in vivo. In brain slices, cell-attached recordings of membrane potential show that CO2/H+-sensitive NTS neurons are activated by focal ATP application; however, purinergic P2-receptor blockade did not affect their CO2/H+ responsiveness. CO2/H+-sensitive raphe neurons were unaffected by ATP or P2-receptor blockade. In vivo, ATP injection into the NTS increased cardiorespiratory activity; however, injection of a P2-receptor blocker into this region had no effect on baseline breathing or CO2/H+ responsiveness. Injections of ATP or a P2-receptor blocker into the medullary raphe had no effect on cardiorespiratory activity or the chemoreflex. As a positive control we confirmed that ATP injection into the RTN increased breathing and blood pressure by a P2-receptor-dependent mechanism. These results suggest that purinergic signalling is a unique feature of RTN chemoreception. PMID:24445316

  3. Characteristics of rostral solitary tract nucleus neurons with identified afferent connections that project to the parabrachial nucleus in rats.

    PubMed

    Suwabe, Takeshi; Bradley, Robert M

    2009-07-01

    Afferent information derived from oral chemoreceptors is transmitted to second-order neurons in the rostral solitary tract nucleus (rNST) and then relayed to other CNS locations responsible for complex sensory and motor behaviors. Here we investigate the characteristics of rNST neurons sending information rostrally to the parabrachial nucleus (PBN). Afferent connections to these rNST-PBN projection neurons were identified by anterograde labeling of the chorda tympani (CT), glossopharyngeal (IX), and lingual (LV) nerves. We used voltage- and current-clamp recordings in brain slices to characterize the expression of both the transient A-type potassium current, IKA and the hyperpolarization-activated inward current, Ih, important determinants of neuronal repetitive discharge characteristics. The majority of rNST-PBN neurons express IKA, and these IKA-expressing neurons predominate in CT and IX terminal fields but were expressed in approximately half of the neurons in the LV field. rNST-PBN neurons expressing Ih were evenly distributed among CT, IX and LV terminal fields. However, expression patterns of IKA and Ih differed among CT, IX, and LV fields. IKA-expressing neurons frequently coexpress Ih in CT and IX terminal fields, whereas neurons in LV terminal field often express only Ih. After GABAA receptor block all rNST-PBN neurons responded to afferent stimulation with all-or-none excitatory synaptic responses. rNST-PBN neurons had either multipolar or elongate morphologies and were distributed throughout the rNST, but multipolar neurons were more often encountered in CT and IX terminal fields. No correlation was found between the biophysical and morphological characteristics of the rNST-PBN projection neurons in each terminal field.

  4. Distinct roles of oxidative stress and antioxidants in the nucleus dorsalis and red nucleus following spinal cord hemisection.

    PubMed

    Xu, Mei; Yip, George Wai-Cheong; Gan, Le-Ting; Ng, Yee-Kong

    2005-09-07

    Oxidative stress plays an important role in the pathogenesis of neurodegeneration after the acute central nervous system injury. We reported previously that increased nitric oxide (NO) production following spinal cord hemisection tends to lead to neurodegeneration in neurons of the nucleus dorsalis (ND) that normally lacks expression of neuronal NO synthase (nNOS) in opposition to those in the red nucleus (RN) that constitutively expresses nNOS. We wondered whether oxidative stress could be a mechanism underlying this NO involved neurodegeneration. In the present study, we examined oxidative damage evaluated by the presence of 4-hydroxynonenal (HNE) and iron accumulation and expression of putative antioxidant enzymes heme oxygenase-1 (HO-1) and superoxide dismutase (SOD) in neurons of the ND and RN after spinal cord hemisection. We found that HNE expression was induced in neurons of the ipsilateral ND from 1 to 14 days following spinal cord hemisection. Concomitantly, iron staining was seen from 7 to 14 days after lesion. HO-1, however, was only transiently induced in ipsilateral ND neurons between 3 and 7 days after lesion. In contrast to the ND neurons, HNE was undetectable and iron level was unaltered in the RN neurons after spinal cord hemisection. HO-1, SOD-Cu/Zn and SOD-Mn were constitutively expressed in RN neurons, and lesion to the spinal cord did not change their expression. These results suggest that oxidative stress is involved in the degeneration of the lesioned ND neurons; whereas constitutive antioxidant enzymes may protect the RN neurons from oxidative damage.

  5. Topography of the 81/P Wild 2 Nucleus Derived from Stardust Stereoimages

    NASA Technical Reports Server (NTRS)

    Kirk, R. L.; Duxbury, T. C.; Horz, F.; Brownlee, D. E.; Newburn, R. L.; Tsou, P.

    2005-01-01

    On 2 January, 2004, the Stardust spacecraft flew by the nucleus of comet 81P/Wild 2 with a closest approach distance of approx. 240 km. During the encounter, the Stardust Optical Navigation Camera (ONC) obtained 72 images of the nucleus with exposure times alternating between 10 ms (near-optimal for most of the nucleus surface) and 100 ms (used for navigation, and revealing additional details in the coma and dark portions of the surface. Phase angles varied from 72 deg. to near zero to 103 deg. during the encounter, allowing the entire sunlit portion of the surface to be imaged. As many as 20 of the images near closest approach are of sufficiently high resolution to be used in mapping the nucleus surface; of these, two pairs of short-exposure images were used to create the nucleus shape model and derived products reported here. The best image resolution obtained was approx. 14 m/pixel, resulting in approx. 300 pixels across the nucleus. The Stardust Wild 2 dataset is therefore markedly superior from a stereomapping perspective to the Deep Space 1 MICAS images of comet Borrelly. The key subset of the latter (3 images) covered only about a quarter of the surface at phase angles approx. 50 - 60 and less than 50 x 160 pixels across the nucleus, yet it sufficed for groups at the USGS and DLR to produce digital elevation models (DEMs) and study the morphology and photometry of the nucleus in detail.

  6. [Extinction of the defensive conditioned reflex in cats after lesioning the endopeduncularis nucleus].

    PubMed

    Sarkisov, T T; Karapetian, L M; Sarkisian, Zh S; Mikaelian, Kh M

    2001-01-01

    Influence of bilateral destruction of nucleus entopeduncularis on the extinction of conditioned avoidance was studied in 10 adult cats. It was shown that bilateral destruction of the nucleus entopeduncularis led to a disturbance of storage of the previous conditioning and facilitated repeated extinction.

  7. Evidence for a motor somatotopy in the cerebellar dentate nucleus--an FMRI study in humans.

    PubMed

    Küper, Michael; Thürling, Markus; Stefanescu, Roxana; Maderwald, Stefan; Roths, Johannes; Elles, Hans G; Ladd, Mark E; Diedrichsen, Jörn; Timmann, Dagmar

    2012-11-01

    Previous anatomical studies in monkeys have shown that forelimb motor representation is located caudal to hindlimb representation within the dorso-rostral dentate nucleus. Here we investigate human dentate nucleus motor somatotopy by means of ultra-highfield (7 T) functional magnetic brain imaging (fMRI). Twenty five young healthy males participated in the study. Simple finger and foot movement tasks were performed to identify dentate nucleus motor areas. Recently developed normalization procedures for group analyses were used for the cerebellar cortex and the cerebellar dentate nucleus. Cortical activations were in good accordance with the known somatotopy of the human cerebellar cortex. Dentate nucleus activations following motor tasks were found in particular in the ipsilateral dorso-rostral nucleus. Activations were also present in other parts of the nucleus including the contralateral side, and there was some overlap between the body part representations. Within the ipsilateral dorso-rostral dentate, finger activations were located caudally compared to foot movement-related activations in fMRI group analysis. Likewise, the centre of gravity (COG) for the finger activation was more caudal than the COG of the foot activation across participants. A multivariate analysis of variance (MANOVA) on the x, y, and z coordinates of the COG indicated that this difference was significant (P = 0.043). These results indicate that in humans, the lower and upper limbs are arranged rostro-caudally in the dorsal aspect of the dentate nucleus, which is consistent with studies in non-human primates.

  8. Formation of the dumbbell-like nucleus of a comet by sublimation

    NASA Astrophysics Data System (ADS)

    Vavilov, Dmitrii; Medvedev, Yurii; Zatitskiy, Pavel

    2016-10-01

    The nucleus of the comet 67P/Churyumov-Gerasimenko is an elongated body with a deep groove around the middle. There are also other comets that look like dumbbells (e.g. 103P/Hartley 2, 19P/Borrelly, 1P/Halley). Two most probable interpretations are discussed in the scientific society. The first hypothesis explains the creation of such an object as sticking of two cometesimals during the process of formation. The second one suggests that the sublimation process can change the nucleus shape and make a groove in the middle.In this work we consider the second hypothesis. It was assumed that the spin axis of the nucleus is perpendicular to the plane of the cometary orbit and that initially the nucleus shape is a sphere. Thus, the problem is represented as a differential equation, which describes the change of the cometary nucleus. We solved this equation analytically. It was shown that initially a convex cometary nucleus (e.g. a sphere), consisting of homogeneous material, can not be transformed into a dumbbell-like body by the influence of sublimation. However, assuming that the density in the centre of the nucleus is less than on the surface, a groove can arise on the equator of the cometary nucleus as a result of sublimation.

  9. Attributed relational graphs for cell nucleus segmentation in fluorescence microscopy images.

    PubMed

    Arslan, Salim; Ersahin, Tulin; Cetin-Atalay, Rengul; Gunduz-Demir, Cigdem

    2013-06-01

    More rapid and accurate high-throughput screening in molecular cellular biology research has become possible with the development of automated microscopy imaging, for which cell nucleus segmentation commonly constitutes the core step. Although several promising methods exist for segmenting the nuclei of monolayer isolated and less-confluent cells, it still remains an open problem to segment the nuclei of more-confluent cells, which tend to grow in overlayers. To address this problem, we propose a new model-based nucleus segmentation algorithm. This algorithm models how a human locates a nucleus by identifying the nucleus boundaries and piecing them together. In this algorithm, we define four types of primitives to represent nucleus boundaries at different orientations and construct an attributed relational graph on the primitives to represent their spatial relations. Then, we reduce the nucleus identification problem to finding predefined structural patterns in the constructed graph and also use the primitives in region growing to delineate the nucleus borders. Working with fluorescence microscopy images, our experiments demonstrate that the proposed algorithm identifies nuclei better than previous nucleus segmentation algorithms.

  10. Hoechst tagging: a modular strategy to design synthetic fluorescent probes for live-cell nucleus imaging.

    PubMed

    Nakamura, Akinobu; Takigawa, Kazumasa; Kurishita, Yasutaka; Kuwata, Keiko; Ishida, Manabu; Shimoda, Yasushi; Hamachi, Itaru; Tsukiji, Shinya

    2014-06-11

    We report a general strategy to create small-molecule fluorescent probes for the nucleus in living cells. Our strategy is based on the attachment of the DNA-binding Hoechst compound to a fluorophore of interest. Using this approach, simple fluorescein, BODIPY, and rhodamine dyes were readily converted to novel turn-on fluorescent nucleus-imaging probes.

  11. Phylogeny of nucleus medianus of the posterior tubercle in rayfinned fishes.

    PubMed

    Northcutt, R Glenn

    2009-03-01

    The brains of ray-finned fishes form a morphocline of increasing complexity, from cladistians through teleosts. This is particularly apparent in the posterior tubercle of the diencephalon. In cladistians, the posterior tubercle consists of a periventricular nucleus and a migrated nucleus medianus that is fused across the midline. In more advanced ray-finned fishes, such as gars and bowfins, the posterior tubercle comprises numerous additional migrated nuclei, termed the preglomerular complex, in addition to a more well developed nucleus medianus. In teleosts, the most derived ray-finned fishes, there is an even more elaborate preglomerular complex, but there is no recognizable nucleus medianus. In an attempt to explain the variation in the posterior tubercle of the diencephalon in ray-finned fishes, the immunohistochemistry and connections of nucleus medianus were examined in cladistians, gars and bowfins. In each of these taxa, nucleus medianus exhibits large numbers of calretinin-positive neurons and has ascending projections that terminate in several divisions of the pallium. Although teleosts, such as goldfish, also exhibit numerous cell groups in the posterior tubercle that are rich in calretinin, none of these cell groups has connections that are comparable to those of nucleus medianus in non-teleost ray-finned fishes. It is possible, therefore, that nucleus medianus was lost with the origin of teleosts.

  12. SF-1 in the ventral medial hypothalamic nucleus: A key regulator of homeostasis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The ventral medial hypothalamic nucleus (VMH) regulates food intake and body weight homeostasis. The nuclear receptor NR5A1 (steroidogenic factor 1; SF-1) is a transcription factor whose expression is highly restricted in the VMH and is required for the development of the nucleus. Neurons expressing...

  13. Effects of cytotoxic nucleus accumbens lesions on instrumental conditioning in rats.

    PubMed

    de Borchgrave, R; Rawlins, J N P; Dickinson, A; Balleine, B W

    2002-05-01

    In two experiments the involvement of the nucleus accumbens in instrumental conditioning was investigated using rats as subjects. In experiment 1, extensive bilateral cytotoxic lesions of the nucleus accumbens mildly suppressed instrumental responding reinforced with food, but had no detectable effect on the sensitivity of the rats' performance either to outcome devaluation or to degradation of the instrumental contingency. In experiment 2, restricted accumbens lesions reliably attenuated the excitatory effect of systemically administered d-amphetamine on lever pressing for a conditioned reinforcer, and completely abolished Pavlovian-instrumental transfer. Taken together these results give a picture of the involvement of the rat nucleus accumbens in instrumental conditioning. They support the widely held theory that the nucleus accumbens mediates the excitatory effects of appetitively conditioned Pavlovian signals on instrumental performance and refute the hypothesis that the nucleus accumbens is part of the neural circuitry by which incentive value is attached to the representations of instrumental outcomes.

  14. Sex difference in Onuf’s nucleus homologue in the Asian musk shrew

    PubMed Central

    Polak, Kathryn; Freeman, Louise M.

    2010-01-01

    Perineal muscles essential for copulatory functioning are innvervated by Onuf’s nucleus in humans and the spinal nucleus of the bulbocavernosus (SNB) and dorsolateral nucleus (DLN) in rats. These structures sexually differentiate as a result of developmental androgen exposure in most species examined. The homologous structure in the Asian musk shrew (Suncus murinus) is a single cluster in the lateral DLN/Onuf’s position in the ventral horn of the spinal cord; these motoneurons innervate both the bulbocavernosus and ischiocavernosus muscles of the musk shrew. We found the expected sex difference in motoneuron number in the shrew DLN, but not in two neighboring motoneuron clusters, the retrodorsolateral nucleus (RDLN) and ventrolateral nucleus (VLN). Male musk shrews also have significantly larger soma areas in the VLN and DLN than females, and male DLN motoneurons have significantly larger nuclei than female. The sex difference in DLN motoneuron number was evident both in raw counts and after accounting for split nuclei error. PMID:20510680

  15. Towards an integrated understanding of the structure and mechanics of the cell nucleus.

    PubMed

    Rowat, Amy C; Lammerding, Jan; Herrmann, Harald; Aebi, Ueli

    2008-03-01

    Changes in the shape and structural organization of the cell nucleus occur during many fundamental processes including development, differentiation and aging. In many of these processes, the cell responds to physical forces by altering gene expression within the nucleus. How the nucleus itself senses and responds to such mechanical cues is not well understood. In addition to these external forces, epigenetic modifications of chromatin structure inside the nucleus could also alter its physical properties. To achieve a better understanding, we need to elucidate the relationship between nuclear structure and material properties. Recently, new approaches have been developed to systematically investigate nuclear mechanical properties. These experiments provide important new insights into the disease mechanism of a growing class of tissue-specific disorders termed 'nuclear envelopathies'. Here we review our current understanding of what determines the shape and mechanical properties of the cell nucleus.

  16. Cardiovascular response to renin substrate microinjection into the central nucleus of the amygdala of rats.

    PubMed

    Heshmatian, Behnam; Parviz, Mohsen; Karimian, Sayed Morteza; Keshavarz, Mansoor; Sohanaki, Hamid

    2007-05-07

    Central nucleus of the amygdala is involved in cardiovascular regulation. Although most components of the renin-angiotensin system have been found to be distributed in amygdala, renin expression in brain has remained controversial. This work was undertaken to elucidate the extent of renin presence in this nucleus. A cannula was implanted bilaterally into the central nucleus of the amygdala. Mean arterial pressure and heart rate were directly measured via indwelling femoral artery cannula post bilateral intra central nucleus of the amygdala microinjection of renin substrate. Renin substrate microinjection dose-dependently increased mean arterial pressure and heart rate, whereas captopril, saralasin and losartan pretreatment inhibited these effects. The results suggest the presence of local renin or similar proteases in this nucleus.

  17. Planar multipolar cells in the cochlear nucleus project to medial olivocochlear neurons in mouse.

    PubMed

    Darrow, Keith N; Benson, Thane E; Brown, M Christian

    2012-05-01

    Medial olivocochlear (MOC) neurons originate in the superior olivary complex and project to the cochlea, where they act to reduce the effects of noise masking and protect the cochlea from damage. MOC neurons respond to sound via a reflex pathway; however, in this pathway the cochlear nucleus cell type that provides input to MOC neurons is not known. We investigated whether multipolar cells of the ventral cochlear nucleus have projections to MOC neurons by labeling them with injections into the dorsal cochlear nucleus. The projections of one type of labeled multipolar cell, planar neurons, were traced into the ventral nucleus of the trapezoid body, where they were observed terminating on MOC neurons (labeled in some cases by a second cochlear injection of FluoroGold). These terminations formed what appear to be excitatory synapses, i.e., containing small, round vesicles and prominent postsynaptic densities. These data suggest that cochlear nucleus planar multipolar neurons drive the MOC neuron's response to sound.

  18. Visual discrimination in the pigeon (Columba livia): effects of selective lesions of the nucleus rotundus

    NASA Technical Reports Server (NTRS)

    Laverghetta, A. V.; Shimizu, T.

    1999-01-01

    The nucleus rotundus is a large thalamic nucleus in birds and plays a critical role in many visual discrimination tasks. In order to test the hypothesis that there are functionally distinct subdivisions in the nucleus rotundus, effects of selective lesions of the nucleus were studied in pigeons. The birds were trained to discriminate between different types of stationary objects and between different directions of moving objects. Multiple regression analyses revealed that lesions in the anterior, but not posterior, division caused deficits in discrimination of small stationary stimuli. Lesions in neither the anterior nor posterior divisions predicted effects in discrimination of moving stimuli. These results are consistent with a prediction led from the hypothesis that the nucleus is composed of functional subdivisions.

  19. A light and electron microscope study of rat abducens nucleus neurons projecting to the cerebellar flocculus.

    PubMed Central

    Rodella, L; Rezzani, R; Corsetti, G; Simonetti, C; Stacchiotti, A; Ventura, R G

    1995-01-01

    Injection of horseradish peroxidase (HRP) into the cerebellar flocculus of the rat was employed to identify neurons in the abducens nucleus that project to the flocculus. The number, ultrastructural features and precise localisation of these neurons in the nucleus were examined. They were present bilaterally and represented about 7% of the total neuronal population of each nucleus. They were localised principally in the dorsomedial area of the cranial half of each nucleus and did not display the typical ultrastructural features of motoneurons. It is concluded that the localisation and ultrastructural characteristics of these HRP-positive neurons are useful for distinguishing them from other neuronal populations within the nucleus. Images Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 7 Fig. 8 PMID:7649835

  20. Synaptic endfeet in the 'acoustic nerve nucleus' of the rat. An electron microscopic study.

    PubMed Central

    Alvarez-Bolado, G; Merchán, J

    1988-01-01

    The medial portion of the cochlear nerve of the rat contains astrocytes, oligodendrocytes and neurons. These neurons form what has been called the 'acoustic nerve nucleus'. This nucleus has been studied here at the electron microscopic level. Its neurons are large and round, showing an eccentric nucleus, fibrillary bodies and rough endoplasmic reticulum which is not arranged in stacks. The somata and dendrites receive synaptic endfeet which can be classified into three groups according to vesicle size and shape. In general, the ultrastructural characteristics of these cells are similar to those of bushy cells as reported by other authors. The 'acoustic nerve nucleus' can be considered to be the most peripheral part of the anterior ventral cochlear nucleus. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 7 Fig. 8 Fig. 9 Fig. 10 Fig. 11 Fig. 12 Fig. 13 Fig. 14 PMID:3248967

  1. GABAergic Projections to the Oculomotor Nucleus in the Goldfish (carassius Auratus)

    PubMed Central

    Luque, M. Angeles; Torres-Torrelo, Julio; Carrascal, Livia; Torres, Blas; Herrero, Luis

    2010-01-01

    The mammalian oculomotor nucleus receives a strong γ-aminobutyric acid (GABA)ergic synaptic input, whereas such projections have rarely been reported in fish. In order to determine whether this synaptic organization is preserved across vertebrates, we investigated the GABAergic projections to the oculomotor nucleus in the goldfish by combining retrograde transport of biotin dextran amine, injected into the antidromically identified oculomotor nucleus, and GABA immunohistochemistry. The main source of GABAergic afferents to the oculomotor nucleus was the ipsilateral anterior octaval nucleus, with only a few, if any, GABAergic neurons being located in the contralateral tangential and descending nuclei of the octaval column. In mammals there is a nearly GABAergic inhibitory inputs; thus, the vestibulooculomotor GABAergic circuitry follows a plan that appears to be shared throughout the vertebrate phylogeny. The second major source of GABAergic projections was the rhombencephalic reticular formation, primarily from the medial area but, to a lesser extent, from the inferior area. A few GABAergic oculomotor projecting neurons were also observed in the ipsilateral nucleus of the medial longitudinal fasciculus. The GABAergic projections from neurons located in both the reticular formation surrounding the abducens nucleus and the nucleus of the medial reticular formation have primarily been related to the control of saccadic eye movements. Finally, all retrogradely labeled internuclear neurons of the abducens nucleus, and neurons in the cerebellum (close to the caudal lobe), were negative for GABA. These data suggest that the vestibuloocular and saccadic inhibitory GABAergic systems appear early in vertebrate phylogeny to modulate the firing properties of the oculomotor nucleus motoneurons. PMID:21331170

  2. Finite Element Study of a Lumbar Intervertebral Disc Nucleus Replacement Device.

    PubMed

    Coogan, Jessica S; Francis, W Loren; Eliason, Travis D; Bredbenner, Todd L; Stemper, Brian D; Yoganandan, Narayan; Pintar, Frank A; Nicolella, Daniel P

    2016-01-01

    Nucleus replacement technologies are a minimally invasive alternative to spinal fusion and total disc replacement that have the potential to reduce pain and restore motion for patients with degenerative disc disease. Finite element modeling can be used to determine the biomechanics associated with nucleus replacement technologies. The current study focuses on a new nucleus replacement device designed as a conforming silicone implant with an internal void. A validated finite element model of the human lumbar L3-L4 motion segment was developed and used to investigate the influence of the nucleus replacement device on spine biomechanics. In addition, the effect of device design changes on biomechanics was determined. A 3D, L3-L4 finite element model was constructed from medical imaging data. Models were created with the normal intact nucleus, the nucleus replacement device, and a solid silicone implant. Probabilistic analysis was performed on the normal model to provide quantitative validation metrics. Sensitivity analysis was performed on the silicone Shore A durometer of the device. Models were loaded under axial compression followed by flexion/extension, lateral bending, or axial rotation. Compressive displacement, endplate stresses, reaction moment, and annulus stresses were determined and compared between the different models. The novel nucleus replacement device resulted in similar compressive displacement, endplate stress, and annulus stress and slightly higher reaction moment compared with the normal nucleus. The solid implant resulted in decreased displacement, increased endplate stress, decreased annulus stress, and decreased reaction moment compared with the novel device. With increasing silicone durometer, compressive displacement decreased, endplate stress increased, reaction moment increased, and annulus stress decreased. Finite element analysis was used to show that the novel nucleus replacement device results in similar biomechanics compared with the

  3. Finite Element Study of a Lumbar Intervertebral Disc Nucleus Replacement Device

    PubMed Central

    Coogan, Jessica S.; Francis, W. Loren; Eliason, Travis D.; Bredbenner, Todd L.; Stemper, Brian D.; Yoganandan, Narayan; Pintar, Frank A.; Nicolella, Daniel P.

    2016-01-01

    Nucleus replacement technologies are a minimally invasive alternative to spinal fusion and total disc replacement that have the potential to reduce pain and restore motion for patients with degenerative disc disease. Finite element modeling can be used to determine the biomechanics associated with nucleus replacement technologies. The current study focuses on a new nucleus replacement device designed as a conforming silicone implant with an internal void. A validated finite element model of the human lumbar L3–L4 motion segment was developed and used to investigate the influence of the nucleus replacement device on spine biomechanics. In addition, the effect of device design changes on biomechanics was determined. A 3D, L3–L4 finite element model was constructed from medical imaging data. Models were created with the normal intact nucleus, the nucleus replacement device, and a solid silicone implant. Probabilistic analysis was performed on the normal model to provide quantitative validation metrics. Sensitivity analysis was performed on the silicone Shore A durometer of the device. Models were loaded under axial compression followed by flexion/extension, lateral bending, or axial rotation. Compressive displacement, endplate stresses, reaction moment, and annulus stresses were determined and compared between the different models. The novel nucleus replacement device resulted in similar compressive displacement, endplate stress, and annulus stress and slightly higher reaction moment compared with the normal nucleus. The solid implant resulted in decreased displacement, increased endplate stress, decreased annulus stress, and decreased reaction moment compared with the novel device. With increasing silicone durometer, compressive displacement decreased, endplate stress increased, reaction moment increased, and annulus stress decreased. Finite element analysis was used to show that the novel nucleus replacement device results in similar biomechanics compared with

  4. Dose enhancement effects to the nucleus and mitochondria from gold nanoparticles in the cytosol

    NASA Astrophysics Data System (ADS)

    McNamara, A. L.; Kam, W. W. Y.; Scales, N.; McMahon, S. J.; Bennett, J. W.; Byrne, H. L.; Schuemann, J.; Paganetti, H.; Banati, R.; Kuncic, Z.

    2016-08-01

    Gold nanoparticles (GNPs) have shown potential as dose enhancers for radiation therapy. Since damage to the genome affects the viability of a cell, it is generally assumed that GNPs have to localise within the cell nucleus. In practice, however, GNPs tend to localise in the cytoplasm yet still appear to have a dose enhancing effect on the cell. Whether this effect can be attributed to stress-induced biological mechanisms or to physical damage to extra-nuclear cellular targets is still unclear. There is however growing evidence to suggest that the cellular response to radiation can also be influenced by indirect processes induced when the nucleus is not directly targeted by radiation. The mitochondrion in particular may be an effective extra-nuclear radiation target given its many important functional roles in the cell. To more accurately predict the physical effect of radiation within different cell organelles, we measured the full chemical composition of a whole human lymphocytic JURKAT cell as well as two separate organelles; the cell nucleus and the mitochondrion. The experimental measurements found that all three biological materials had similar ionisation energies  ˜70 eV, substantially lower than that of liquid water  ˜78 eV. Monte Carlo simulations for 10-50 keV incident photons showed higher energy deposition and ionisation numbers in the cell and organelle materials compared to liquid water. Adding a 1% mass fraction of gold to each material increased the energy deposition by a factor of  ˜1.8 when averaged over all incident photon energies. Simulations of a realistic compartmentalised cell show that the presence of gold in the cytosol increases the energy deposition in the mitochondrial volume more than within the nuclear volume. We find this is due to sub-micron delocalisation of energy by photoelectrons, making the mitochondria a potentially viable indirect radiation target for GNPs that localise to the cytosol.

  5. Are Quasars Ejected from the Nucleus of NGC 4258?

    NASA Astrophysics Data System (ADS)

    Kondratko, P. T.; Greenhill, L. J.; Moran, J. M.

    2001-12-01

    The H2O maser in NGC 4258 traces a thin, almost edge-on, and slightly warped molecular disk around a supermassive black hole. Extensive measurements of the positions, three dimensional velocity vectors, and accelerations of dozens of masers are well explained by a simple disk model. However, discovery of two quasars with redshifts 0.39 and 0.65 symmetrically displaced by ~ 9' from the nucleus of NGC 4258 and located approximately at the position angle of the maser disk has fueled an alternative hypothesis by G. Burbidge, E.M. Burbidge, and co-workers. They proposed that the two quasars were ejected from the nucleus, are dynamically associated with the maser, and possess redshifts which are primarily non-cosmological in origin. We use 3 epochs of 20 cm VLBA images of one of the quasars and of NGC 4258 to derive an upper limit on the quasar proper motion of 0.4 mas year-1 (0.05 c) in the putative direction of ejection and with respect to the continuum emission from NGC 4258. This upper limit excludes the Ozernoy model in which the redshifts of the two quasars are primarily due to the transverse Doppler effect caused by a tranverse velocity of 6.6 mas year-1 (0.75 c). In addition to fixing an upper limit on the quasar proper motion, the images of NGC 4258 jet reveal a dominant, apparently stationary component located approximately ~ 6 mas north from the black hole and corresponding to the northern core of the jet. The distance of the core from the black hole scales with λ as expected in the standard model of Blandford and Königl. The southern jet core is undetected perhaps due to high optical depth associated with a hot, ionized wind or with an ionized material in the disk. The jet in the immediate vicinity of the central engine is characterized by γ >4.3, which appears to be relatively stable over time.

  6. Near-nucleus photometry of comets using archived NEAT data

    NASA Astrophysics Data System (ADS)

    Hicks, Michael D.; Bambery, Raymond J.; Lawrence, Kenneth J.; Kollipara, Priya

    2007-06-01

    Though optimized to discover and track fast moving Near-Earth Objects (NEOs), the Near-Earth Asteroid Tracking (NEAT) survey dataset can be mined to obtain information on the comet population observed serendipitously during the asteroid survey. We have completed analysis of over 400 CCD images of comets obtained during the autonomous operations of two 1.2-m telescopes: the first on the summit of Haleakala on the Hawaiian island of Maui and the second on Palomar Mountain in southern California. Photometric calibrations of each frame were derived using background catalog stars and the near-nucleus comet photometry measured. We measured dust production and normalized magnitudes for the coma and nucleus in order to explore cometary activity and comet size-frequency distributions. Our data over an approximately two-year time frame (2001 August-2003 February) include 52 comets: 12 periodic, 19 numbered, and 21 non-periodic, obtained over a wide range of viewing geometries and helio/geocentric distances. Nuclear magnitudes were estimated for a subset of comets observed. We found that for low-activity comets ( Afρ<100 cm) our model gave reasonable estimates for nuclear size and magnitude. The slope of the cumulative luminosity function of our sample of low-activity comets was 0.33 ± 0.04, consistent with the slope we measured for the Jupiter-family cometary nuclei collected by Fernández et al. [Fernández, J.A., Tancredi, G., Rickman, H., Licandro, J., 1999. Astron. Astrophys. 392, 327-340] of 0.38 ± 0.02. Our slopes of the cumulative size distribution α=1.50±0.08 agree well with the slopes measured by Whitman et al. [Whitman, K., Morbidelli, A., Jedicke, R., 2006. Icarus 183, 101-114], Meech et al. [Meech, K.J., Hainaut, O.R., Marsden, B.G., 2004. Icarus 170, 463-491], Lowry et al. [Lowry, S.C., Fitzsimmons, A., Collander-Brown, S., 2003. Astron. Astrophys. 397, 329-343], and Weissman and Lowry [Weissman, P.R., Lowry, S.C., 2003. Lunar Planet. Sci. 34. Abstract 34].

  7. The primordial nucleus of Comet 67P/Churyumov-Gerasimenko

    NASA Astrophysics Data System (ADS)

    Davidsson, Bjorn; Sierks, Holger; Guettler, Carsten; Marzari, Francesco; Pajola, Maurizio; Rickman, Hans; A'Hearn, Michael; Auger, Anne-Therese; El-Maarry, Mohamed; Fornasier, Sonia; Gutierrez, Pedro; Keller, Horst Uwe; Massironi, Matteo; Snodgrass, Colin; Vincent, Jean-Baptiste; Barbieri, Cesare; Lamy, Philippe; Rodrigo, Rafael; Koschny, Detlef; Barucci, Antonella; Bertaux, Jean-Loup; Bertini, Ivano; Cremonese, Gabriele; Da Deppo, Vania; Debei, Stefano; De Cecco, Mariolino; Feller, Clement; Fulle, Marco; Groussin, Olivier; Hviid, Stubbe; Hoefner, Sebastian; Ip, Wing-Huen; Jorda, Laurent; Knollenberg, Joerg; Kovacs, Gabor; Kramm, Joerg-Rainer; Kuehrt, Ekkehard; Kueppers, Michael; La Forgia, Fiorangela; Lara, Luisa; Lazzarin, Monica; Lopez Moreno, Jose; Moissl-Fraund, Richard; Mottola, Stefano; Naletto, Giampiero; Oklay, Nilda; Thomas, Nicolas; Tubiana, Cecilia

    2015-11-01

    Observations of Comet 67P/Churyumov-Gerasimenko by Rosetta show that the nucleus is bi-lobed, extensively layered, has a low bulk density, a high dust-to-ice mass ratio (implying high porosity), and weak strength except for a thin sintered surface layer. The comet is rich in supervolatiles (CO, CO2, N2), may contain amorphous water ice, and displays little to no signs of aqueous alteration. Lack of phyllosilicates in Stardust samples from Comet 81P/Wild 2 provides further support that comet nuclei did not contain liquid water.These properties differ from those expected for 50-200 km diameter bodies in the primordial disk. We find that thermal processing due to Al-26, combined with collisional compaction, creates a population of medium-sized bodies that are comparably dense, compacted, strong, heavily depleted in supervolatiles, containing little to no amorphous water ice, and that have experienced extensive aqueous alteration. Irregular satellites Phoebe and Himalia are potential representatives of this population. Collisional rubble piles inherit these properties from their parents. We therefore conclude that observed comet nuclei are primordial rubble piles, and not collisional rubble piles.We propose a concurrent comet and TNO formation scenario that is consistent with these observations. We argue that TNOs form due to streaming instabilities at sizes of about 50-400 km and that about 350 of these grow slowly in a low-mass primordial disk to the size of Triton, causing little viscous stirring during growth. We propose a dynamically cold primordial disk, that prevents medium-sized TNOs from breaking into collisional rubble piles, and allows for the survival of primordial rubble-pile comets. We argue that comets form by hierarchical agglomeration out of material that remains after TNO formation. This slow growth is necessary to avoid thermal processing by Al-26, and to allow comet nuclei to incorporate 3 Myr old material from the inner Solar System, found in

  8. Hypoglycemia-activated GLUT2 neurons of the nucleus tractus solitarius stimulate vagal activity and glucagon secretion.

    PubMed

    Lamy, Christophe M; Sanno, Hitomi; Labouèbe, Gwenaël; Picard, Alexandre; Magnan, Christophe; Chatton, Jean-Yves; Thorens, Bernard

    2014-03-04

    Glucose-sensing neurons in the brainstem participate in the regulation of energy homeostasis but have been poorly characterized because of the lack of specific markers to identify them. Here we show that GLUT2-expressing neurons of the nucleus of the tractus solitarius form a distinct population of hypoglycemia-activated neurons. Their response to low glucose is mediated by reduced intracellular glucose metabolism, increased AMP-activated protein kinase activity, and closure of leak K(+) channels. These are GABAergic neurons that send projections to the vagal motor nucleus. Light-induced stimulation of channelrhodospin-expressing GLUT2 neurons in vivo led to increased parasympathetic nerve firing and glucagon secretion. Thus GLUT2 neurons of the nucleus tractus solitarius link hypoglycemia detection to counterregulatory response. These results may help identify the cause of hypoglycemia-associated autonomic failure, a major threat in the insulin treatment of diabetes.

  9. Particle production in the Color Glass Condensate: from electron-proton DIS to proton-nucleus collisions

    NASA Astrophysics Data System (ADS)

    Lappi, T.; Mäntysaari, H.

    2014-06-01

    We study single inclusive hadron production in proton-proton and proton-nucleus collisions in the CGC framework. The parameters in the calculation are obtained by fitting electron-proton deep inelastic scattering data. The obtained dipole-proton amplitude is generalized to dipole-nucleus scattering without any additional nuclear parameters other than the Woods-Saxon distribution. We show that it is possible to use an initial condition without an anomalous dimension and still obtain a good description of the HERA inclusive cross section and LHC single particle production measurements. We argue that one must consistently use the proton transverse area as measured by a high virtuality probe in DIS also for the single inclusive cross section in proton-proton and proton-nucleus collisions, and obtain a nuclear modification factor RpA that at midrapidity approaches unity at large momenta and at all energies.

  10. New aspects in nucleon-nucleus collisions and EAS properties around 10(6) GeV

    NASA Technical Reports Server (NTRS)

    Capdevielle, J. N.; Gawin, J.

    1985-01-01

    At energies higher than 2 x 10 to the 5 GeV, very little information exists on detailed properties of nucleon-nucleon collision; the rare elements are coming from jets, and, as nondirect improvements from gamma-ray families. The results exhibit some conflicting features, or, at least, very large fluctuations like copious production of gamma-rays in opposition to Centauro-like events, sometimes suggest that phase transition to quark gluon plasma occurs in nucleus-nucleus collisions and even in nucleon-nucleus collision. The multicluster phenomenological model (MPM) extrapolated for extensive air showers EAS simulation up to 5 x 10 to the 6 GeV to put in evidence some significant deviation between experimental data and prediction.

  11. Solar Sail Application to Comet Nucleus Sample Return

    NASA Technical Reports Server (NTRS)

    Taylor, Travis S.; Moton, Tryshanda T.; Robinson, Don; Anding, R. Charles; Matloff, Gregory L.; Garbe, Gregory; Montgomery, Edward

    2003-01-01

    Many comets have perihelions at distances within 1.0 Astronomical Unit (AU) from the sun. These comets typically are inclined out of the ecliptic. We propose that a solar sail spacecraft could be used to increase the inclination of the orbit to match that of these 1.0 AU comets. The solar sail spacecraft would match the orbit velocity for a short period of time, which would be long enough for a container to be injected into the comet's nucleus. The container would be extended from a long durable tether so that the solar sail would not be required to enter into the potentially degrading environment of the comet s atmosphere. Once the container has been filled with sample material, the tether is retracted. The solar sail would then lower its inclination and fly back to Earth for the sample return. In this paper, we describe the selection of cometary targets, the mission design, and the solar sailcraft design suitable for sail-comet rendezvous as well as possible rendezvous scenarios.

  12. Culturing bovine nucleus pulposus explants by balancing medium osmolarity.

    PubMed

    van Dijk, Bart; Potier, Esther; Ito, Keita

    2011-11-01

    Regenerative therapies are promising treatments for early intervertebral disc degeneration. To test their efficacy, an in vitro tissue-level model would be valuable. Nucleus pulposus (NP) explant culture may constitute such a model, as the earliest signs of degeneration are in the NP. However, in NP explant cultures, balancing tissue osmolarity is crucial to preventing swelling, proteoglycan (PG) loss and, therefore, maintaining a native cell environment. In this study, we investigated the effect of medium osmolarity on NP explants. We hypothesized that balancing the inherent tissue osmolarity would prevent swelling and thus maintain NP tissue in a native state. Bovine NP explants were cultured for 21 days in hypo-, iso-, and hyper-tonic conditions using either sucrose or polyethylene glycol (PEG) to raise medium osmolarity. Explants were analyzed for water and biochemical content, cell viability, gene expression, and tissue histology, and compared to day 0 samples. In hypo-tonic and both sucrose cultures, swelling was not prevented, resulting in PG loss and changes in cell behavior. Only PEG cultures maintained water and biochemical content and a histological aspect similar to those of native tissue, with better results for hyper- than for iso-tonic conditions. Using PEG to raise culture medium osmolarity, we were able to maintain the NP tissue specific matrix composition, important for disc cell behavior. This approach, thus, constitutes a promising model to test regenerative therapies for early intervertebral disc degeneration.

  13. Nuclear lamina at the crossroads of the cytoplasm and nucleus

    PubMed Central

    Huber, Michael D.

    2012-01-01

    The nuclear lamina is a protein meshwork that lines the nuclear envelope in metazoan cells. It is composed largely of a polymeric assembly of lamins, which comprise a distinct sequence homology class of the intermediate filament protein family. On the basis of its structural properties, the lamina originally was proposed to provide scaffolding for the nuclear envelope and to promote anchoring of chromatin and nuclear pore complexes at the nuclear surface. This viewpoint has expanded greatly during the past 25 years, with a host of surprising new insights on lamina structure, molecular composition and functional attributes. It has been established that the self-assembly properties of lamins are very similar to those of cytoplasmic intermediate filament proteins, and that the lamin polymer is physically associated with components of the cytoplasmic cytoskeleton and with a multitude of chromatin and inner nuclear membrane proteins. Cumulative evidence points to an important role for the lamina in regulating signaling and gene activity, and in mechanically coupling the cytoplasmic cytoskeleton to the nucleus. The significance of the lamina has been vaulted to the forefront by the discovery that mutations in lamins and lamina-associated polypeptides lead to an array of human diseases. A key future challenge is to understand how the lamina integrates pathways for mechanics and signaling at the molecular level. Understanding the structure of the lamina from the atomic to supramolecular levels will be essential for achieving this goal. PMID:22126840

  14. Coilin Shuttles between the Nucleus and Cytoplasm In Xenopus Oocytes

    PubMed Central

    Bellini, Michel; Gall, Joseph G.

    1999-01-01

    Coiled bodies are discrete nuclear organelles often identified by the marker protein p80-coilin. Because coilin is not detected in the cytoplasm by immunofluorescence and Western blotting, it has been considered an exclusively nuclear protein. In the Xenopus germinal vesicle (GV), most coilin actually resides in the nucleoplasm, although it is highly concentrated in 50–100 coiled bodies. When affinity-purified anti-coilin antibodies were injected into the cytoplasm of oocytes, they could be detected in coiled bodies within 2–3 h. Coiled bodies were intensely labeled after 18 h, whereas other nuclear organelles remained negative. Because the nuclear envelope does not allow passive diffusion of immunoglobulins, this observation suggests that anti-coilin antibodies are imported into the nucleus as an antigen–antibody complex with coilin. Newly synthesized coilin is not required, because cycloheximide had no effect on nuclear import and subsequent targeting of the antibodies. Additional experiments with myc-tagged coilin and myc-tagged pyruvate kinase confirmed that coilin is a shuttling protein. The shuttling of Nopp140, NO38/B23, and nucleolin was easily demonstrated by the targeting of their respective antibodies to the nucleoli, whereas anti-SC35 did not enter the germinal vesicle. We suggest that coilin, perhaps in association with Nopp140, may function as part of a transport system between the cytoplasm and the coiled bodies. PMID:10512877

  15. Reduced volume of the nucleus accumbens in heroin addiction.

    PubMed

    Seifert, Christian L; Magon, Stefano; Sprenger, Till; Lang, Undine E; Huber, Christian G; Denier, Niklaus; Vogel, Marc; Schmidt, André; Radue, Ernst-Wilhelm; Borgwardt, Stefan; Walter, Marc

    2015-12-01

    The neural mechanisms of heroin addiction are still incompletely understood, even though modern neuroimaging techniques offer insights into disease-related changes in vivo. While changes on cortical structure have been reported in heroin addiction, evidence from subcortical areas remains underrepresented. Functional imaging studies revealed that the brain reward system and particularly the nucleus accumbens (NAcc) play a pivotal role in the pathophysiology of drug addiction. The aim of this study was to investigate whether there was a volume difference of the NAcc in heroin addiction in comparison to healthy controls. A further aim was to correlate subcortical volumes with clinical measurements on negative affects in addiction. Thirty heroin-dependent patients under maintenance treatment with diacetylmorphine and twenty healthy controls underwent structural MRI scanning at 3T. Subcortical segmentation analysis was performed using FMRIB's Integrated Registration and Segmentation Tool function of FSL. The State-Trait Anxiety Inventory and the Beck Depression Inventory were used to assess trait anxiety and depressive symptoms, respectively. A decreased volume of the left NAcc was observed in heroin-dependent patients compared to healthy controls. Depression score was negatively correlated with left NAcc volume in patients, whereas a positive correlation was found between the daily opioid dose and the volume of the right amygdala. This study indicates that there might be structural differences of the NAcc in heroin-dependent patients in comparison with healthy controls. Furthermore, correlations of subcortical structures with negative emotions and opioid doses might be of future relevance for the investigation of heroin addiction.

  16. Localization and expression of GABA transporters in the suprachiasmatic nucleus

    PubMed Central

    Moldavan, Michael; Cravetchi, Olga; Williams, Melissa; Irwin, Robert P.; Aicher, Sue A.; Allen, Charles N.

    2015-01-01

    GABA is a principal neurotransmitter in the suprachiasmatic hypothalamic nucleus (SCN), the master circadian clock. Despite the importance of GABA and GABA uptake for functioning of the circadian pacemaker, the localization and expression of GABA transporters (GATs) in the SCN has not been investigated. The present studies used Western blot analysis, immunohistochemistry, and electron microscopy to demonstrate the presence of GABA transporter 1 (GAT1) and GABA transporter 3 (GAT3) in the SCN. By light microscopy, GAT1 and GAT3 were co-localized throughout the SCN, but were not expressed in the perikarya of arginine vasopressin- or vasoactive intestinal peptide-immunoreactive (−ir) neurons of adult rats, nor in the neuronal processes labeled with the Neurofilament Heavy Chain. By electron microscopy, GAT1- and GAT3-ir was found in glial processes surrounding unlabeled neuronal perikarya, axons, dendrites, and enveloped symmetric and asymmetric axo-dendritic synapses. Glial Fibrillary Acidic Protein-ir astrocytes grown in cell culture were immunopositive for GAT1 and GAT3 – and both GATs could be observed in the same glial cell. These data demonstrate that synapses in the SCN function as “tripartite” synapses consisting of presynaptic axon terminals, postsynaptic membranes, and astrocytes that contain GABA transporters. This model suggests that astrocytes expressing both GATs may regulate the extracellular GABA, and thereby modulate the activity of neuronal networks in the SCN. PMID:26390912

  17. Advanced glycation end products in degenerative nucleus pulposus with diabetes.

    PubMed

    Tsai, Tsung-Ting; Ho, Natalie Yi-Ju; Lin, Ying-Ting; Lai, Po-Liang; Fu, Tsai-Sheng; Niu, Chi-Chien; Chen, Lih-Huei; Chen, Wen-Jer; Pang, Jong-Hwei S

    2014-02-01

    Diabetes mellitus (DM) has been clinically proved as a risk factor of disc degeneration, and the accumulation of advanced glycation end products (AGEs) is known to be potentially involved in diabetes. The purpose of this study is to investigate the effect of AGEs in the degeneration process of diabetic nucleus pulposus (NP) in rats and humans. Diabetic NP cells from rat coccygeal discs were treated with different concentrations of AGEs (0, 50, and 100 µg/ml) for 3 days, and mRNA expressions of MMP-2 and RAGE were measured by real-time RT-PCR. In addition, conditioned medium from NP cells was used to analyze protein expression of MMP-2 activity and ERK by gelatin zymography and Western blot. These experiments were repeated using human intervertebral disc samples. The immunohistochemical expression of AGEs was significantly increased in diabetic discs. In response to AGEs, an increase of MMP-2, RAGE, and ERK at both mRNA and protein expression levels was observed in diabetic NP cells. The findings suggest that AGEs and DM are associated with disc degeneration in both species. Hyperglycemia in diabetes enhances the accumulation of AGEs in the NP and triggers disc degeneration.

  18. A bushy cell network in the rat ventral cochlear nucleus

    PubMed Central

    Gomez-Nieto, Ricardo; Rubio, Maria E.

    2010-01-01

    Geometry of the dendritic tree and synaptic organization of afferent inputs are essential factors in determining how synaptic input is integrated by neurons. This information remains elusive for one of the first brainstem neurons involved in processing of the primary auditory signal from the ear, the bushy cells (BCs) of the ventral cochlear nucleus (VCN). Here, we labeled the BC dendritic trees with retrograde tracing techniques to analyze their geometry and synaptic organization after immunofluorescence for excitatory and inhibitory synaptic markers, electron microscopy, morphometry, double tract-tracing methods, and 3-D reconstructions. Our study revealed that BC dendrites provide space for a large number of compartmentalized excitatory and inhibitory synaptic interactions. The dendritic inputs on BCs are of cochlear and non-cochlear origin, and their proportion and distribution are dependent on the branching pattern and orientation of the dendritic tree in the VCN. Three-dimensional reconstructions showed that BC dendrites branch and cluster with those of other BCs in the core of the VCN. Within the cluster, incoming synaptic inputs establish divergent multiple-contact synapses (dyads and triads) between BCs. Furthermore, neuron-neuron connections including puncta adherentia, sarcoplasmic junctions and gap junctions are common between BCs, which suggests that these neurons are electrically coupled. Together, our study demonstrates the existence of a BC network in the rat VCN. This network may establish the neuroanatomical basis for acoustic information processing by individual BCs, as well as for enhanced synchronization of the output signal of the VCN. PMID:19634178

  19. Microtubules contribute to maintain nucleus shape in epithelial cell monolayer

    NASA Astrophysics Data System (ADS)

    Tremblay, Dominique; Andrzejewski, Lukasz; Pelling, Andrew

    2013-03-01

    INTRODUCTION: Tissue strains can result in significant nuclear deformations and may regulate gene expression. However, the precise role of the cytoskeleton in regulating nuclear mechanics remains poorly understood. Here, we investigate the nuclear deformability of Madin-Darky canine kidney cells (MDCK) under various stretching conditions to clarify the role of the microtubules and actin network on the mechanical behavior of the nucleus. METHODS: A custom-built cell-stretching device allowing for real time imaging of MDCK nuclei was used. Cells were seeded on a silicone membrane coated with rat-tail collagen I. A nuclear stain, Hoechst-33342, was used to image nuclei during stretching. We exposed cells to a compressive and non-compressive stretching strain field of 25%. Nocodazole and cytochalasin-D were used to depolymerize the microtubules and actin network. RESULTS: Nuclei in control cells stretched more along their minor axis than major axis with a deformation of 5% and 2% respectively. This anisotropy vanished completely in microtubule-deprived cells and these cells showed a very high nuclear deformability along the minor axis when exposed to a compressive stretching strain field. CONCLUSIONS: The microtubules drive the anisotropic deformability of MDCK nuclei in a monolayer and maintain nuclear shape when exposed to compressive strain. Such intrinsic mechanical behavior indicates that microtubules are essential to maintain nuclear shape and may prevent down regulation of gene expression.

  20. Deuterium target data for precision neutrino-nucleus cross sections

    SciTech Connect

    Meyer, Aaron S.; Betancourt, Minerba; Gran, Richard; Hill, Richard J.

    2016-06-23

    Amplitudes derived from scattering data on elementary targets are basic inputs to neutrino-nucleus cross section predictions. A prominent example is the isovector axial nucleon form factor, FA(q2), which controls charged current signal processes at accelerator-based neutrino oscillation experiments. Previous extractions of FA from neutrino-deuteron scattering data rely on a dipole shape assumption that introduces an unquantified error. A new analysis of world data for neutrino-deuteron scattering is performed using a model-independent, and systematically improvable, representation of FA. A complete error budget for the nucleon isovector axial radius leads to rA2 = 0.46(22)fm2, with a much larger uncertainty than determined in the original analyses. The quasielastic neutrino-neutron cross section is determined as σ(νμn → μ-p)|Ev=1GeV = 10.1(0.9)×10-39cm2. The propagation of nucleon-level constraints and uncertainties to nuclear cross sections is illustrated using MINERvA data and the GENIE event generator. Furthermore, these techniques can be readily extended to other amplitudes and processes.

  1. Oxytocin excites nucleus accumbens shell neurons in vivo.

    PubMed

    Moaddab, Mahsa; Hyland, Brian I; Brown, Colin H

    2015-09-01

    Oxytocin modulates reward-related behaviors. The nucleus accumbens shell (NAcSh) is a major relay in the brain reward pathway and expresses oxytocin receptors, but the effects of oxytocin on the activity of NAcSh neurons in vivo are unknown. Hence, we used in vivo extracellular recording to show that intracerebroventricular (ICV) oxytocin administration (0.2μg) robustly increased medial NAcSh neuron mean firing rate; this increase was almost exclusively evident in slow-firing neurons and was not associated with any change in firing pattern. To determine whether oxytocin excitation of medial NAcSh neurons is modulated by drugs that impact the brain reward pathway, we next tested the effects of ICV oxytocin following repeated morphine treatment. In morphine-treated rats, ICV oxytocin did not affect the mean firing rate of medial NAcSh neurons. Taken together, these results show that oxytocin excites medial NAcSh neurons but does not do so after repeated morphine. This could be an important factor in oxytocin modulation of reward-related behaviors, such as drug addiction.

  2. Hsp90 in Cancer: Transcriptional Roles in the Nucleus.

    PubMed

    Calderwood, Stuart K; Neckers, Len

    2016-01-01

    Hsp90 plays a key role in fostering metabolic pathways essential in tumorigenesis through its functions as a molecular chaperone. Multiple oncogenic factors in the membrane and cytoplasm are thus protected from degradation and destruction. Here, we have considered Hsp90's role in transcription in the nucleus. Hsp90 functions both in regulating the activity of sequence-specific transcription factors such as nuclear receptors and HSF1, as well as impacting more globally acting factors that act on chromatin and RNA polymerase II. Hsp90 influences transcription by modulating histone modification mediated by its clients SMYD3 and trithorax/MLL, as well as by regulating the processivity of RNA polymerase II through negative elongation factor. It is not currently clear how the transcriptional role of Hsp90 may be influenced by the cancer milieu although recently discovered posttranslational modification of the chaperone may be involved. Dysregulation of Hsp90 may thus influence malignant processes both by modulating the function of specific transcription factors and effects on more globally acting general components of the transcriptional machinery.

  3. Light-dark cycle memory in the mammalian suprachiasmatic nucleus.

    PubMed

    Ospeck, Mark C; Coffey, Ben; Freeman, Dave

    2009-09-16

    The mammalian circadian oscillator, or suprachiasmatic nucleus (SCN), contains several thousand clock neurons in its ventrolateral division, many of which are spontaneous oscillators with period lengths that range from 22 to 28 h. In complete darkness, this network synchronizes through the exchange of action potentials that release vasoactive intestinal polypeptide, striking a compromise, free-running period close to 24 h long. We entrained Siberian hamsters to various light-dark cycles and then tracked their activity into constant darkness to show that they retain a memory of the previous light-dark cycle before returning to their own free-running period. Employing Leloup-Goldbeter mammalian clock neurons we model the ventrolateral SCN network and show that light acting weakly upon a strongly rhythmic vasoactive intestinal polypeptide oscillation can explain the observed light-dark cycle memory. In addition, light is known to initiate a mitogen-activated protein kinase signaling cascade that induces transcription of both per and mkp1 phosphatase. We show that the ensuing phosphatase-kinase interaction can account for the dead zone in the mammalian phase response curve and hypothesize that the SCN behaves like a lock-in amplifier to entrain to the light edges of the circadian day.

  4. Jet-like features near the Nucleus of Chiron

    NASA Technical Reports Server (NTRS)

    Elliot, J. L.; Olkin, C. B.; Dunham, E. W.; Ford, C. H.; Gilmore, D. K.; Kurtz, D.; Lazzaro, D.; Rank, D. M.; Temi, P.; Bandyopadhyay, R. M.; Barroso, J.; Barrucci, A.; Bosh, A. S.; Buie, M. W.; Bus, S. J.; Dahn, C. C.; Foryta, D. W.; Hubbard, W. B.; Lopes, D. F.; Marcialis, R. L.

    1995-01-01

    Considered as a comet, the object 2060 Chiron is unusual in two respects: it exhibits outbursts at very large distances from the Sun, and its nucleus is much larger than that of any other known comet. It is, however, similar in size to the recently discovered Kuiper-belt objects - a population of objects with orbits beyond Neptune, which are a possible source of short-period comets. This has led to the conjecture that Chiron is related to these objects, but its chaotic orbit has brought it much closer to the Sun. Here we report observations of a recent stellar occultation by Chiron which permit the identification of several features associated with Chiron's coma. The observation of discrete, jet-like features provides evidence that the coma material originates from just few, small active areas, rather than from uniform sublimations, and that the particles in at least one of these features have radii greater than 0.25 microns. The observations also suggest the presence of material in the plane of Chiron's orbit and are consistent with a gravitationally bound coma. Finally, the present data, and those from a previous occultation, constrain the radius of Chiron to lie between 83 and 156 km.

  5. Targeting of nucleus-encoded proteins to chloroplasts in plants.

    PubMed

    Jarvis, Paul

    2008-07-01

    Most chloroplast proteins are encoded in the nucleus and synthesized on free, cytosolic ribosomes in precursor form. Each precursor has an amino-terminal extension called a transit peptide, which directs the protein through a post-translational targeting pathway and is removed upon arrival inside the organelle. This 'protein import' process is mediated by the coordinate action of two multiprotein complexes, one in each of the envelope membranes: the TOC and TIC (Translocon at the Outer/ Inner envelope membrane of Chloroplasts) machines. Many components of these complexes have been identified biochemically in pea; these include transit peptide receptors, channel proteins, and molecular chaperones. Intriguingly, the Arabidopsis genome encodes multiple, homologous genes for receptor components of the TOC complex. Careful analysis indicated that the different receptor isoforms operate in different import pathways with distinct precursor recognition specificities. These 'substrate-specific' import pathways might play a role in the differentiation of different plastid types, and/or act to prevent deleterious competition effects between abundant and nonabundant precursors. Until recently, all proteins destined for internal chloroplast compartments were thought to possess a cleavable transit peptide, and to engage the TOC/TIC machinery. New studies using proteomics and other approaches have revealed that this is far from true. Remarkably, a significant number of chloroplast proteins are transported via a pathway that involves the endoplasmic reticulum and Golgi apparatus. Other recent reports have elucidated an intriguing array of protein targeting routes leading to the envelope membranes themselves.

  6. The highly reduced genome of an enslaved algal nucleus.

    PubMed

    Douglas, S; Zauner, S; Fraunholz, M; Beaton, M; Penny, S; Deng, L T; Wu, X; Reith, M; Cavalier-Smith, T; Maier, U G

    2001-04-26

    Chromophyte algae differ fundamentally from plants in possessing chloroplasts that contain chlorophyll c and that have a more complex bounding-membrane topology. Although chromophytes are known to be evolutionary chimaeras of a red alga and a non-photosynthetic host, which gave rise to their exceptional membrane complexity, their cell biology is poorly understood. Cryptomonads are the only chromophytes that still retain the enslaved red algal nucleus as a minute nucleomorph. Here we report complete sequences for all three nucleomorph chromosomes from the cryptomonad Guillardia theta. This tiny 551-kilobase eukaryotic genome is the most gene-dense known, with only 17 diminutive spliceosomal introns and 44 overlapping genes. Marked evolutionary compaction hundreds of millions of years ago eliminated nearly all the nucleomorph genes for metabolic functions, but left 30 for chloroplast-located proteins. To allow expression of these proteins, nucleomorphs retain hundreds of genetic-housekeeping genes. Nucleomorph DNA replication and periplastid protein synthesis require the import of many nuclear gene products across endoplasmic reticulum and periplastid membranes. The chromosomes have centromeres, but possibly only one loop domain, offering a means for studying eukaryotic chromosome replication, segregation and evolution.

  7. In vivo histamine voltammetry in the mouse premammillary nucleus.

    PubMed

    Samaranayake, Srimal; Abdalla, Aya; Robke, Rhiannon; Wood, Kevin M; Zeqja, Anisa; Hashemi, Parastoo

    2015-06-07

    Histamine plays a major role in the mediation of allergic reactions such as peripheral inflammation. This classical monoamine is also a neurotransmitter involved in the central nervous system but its role in this context is poorly understood. Studying histamine neurotransmission is important due to its implications in many neurological disorders. The sensitivity, selectivity and high temporal resolution of fast scan cyclic voltammetry (FSCV) offer many advantages for studying electroactive neurotransmitters. Histamine has previously been studied with FSCV; however, the lack of a robust Faradaic electrochemical signal makes it difficult to selectively identify histamine in complex media, as found in vivo. In this work, we optimize an electrochemical waveform that provides a stimulation-locked and unique electrochemical signal towards histamine. We describe in vitro waveform optimization and a novel in vivo physiological model for stimulating histamine release in the mouse premammillary nucleus via stimulation of the medial forebrain bundle. We demonstrate that a robust signal can be used to effectively identify histamine and characterize its in vivo kinetics.

  8. The suprachiasmatic nucleus and the circadian timing system.

    PubMed

    Moore, Robert Y

    2013-01-01

    The circadian timing system (CTS) in mammals may be defined as a network of interconnected diencephalic structures that regulate the timing of physiological processes and behavioral state. The central feature of the CTS is the suprachiasmatic nucleus (SCN) of the hypothalamus, a self-sustaining circadian oscillator entrained by visual afferents, input from other brain and peripheral oscillators. The SCN was first noted as a distinct component of the hypothalamus during the late nineteenth century and recognized soon after as a uniform feature of the mammalian and lower vertebrate brain. But, as was true for so many brain components identified in that era, its function was unknown and remained so for nearly a century. In the latter half of the twentieth century, numerous tools for studying the brain were developed including neuroanatomical tracing methods, electrophysiological methods including long-term recording in vivo and in vitro, precise methods for producing localized lesions in the brain, and molecular neurobiology. Application of these methods provided a body of data strongly supporting the view that the SCN is a circadian pacemaker in the mammalian brain. This chapter presents an analysis of the functional organization of the SCN as a component of a neural network, the CTS. This network functions as a coordinator of hypothalamic regulatory systems imposing a temporal organization of physiological processes and behavioral state to promote environmental adaptation.

  9. Neuronal Complexity in Subthalamic Nucleus is Reduced in Parkinson's Disease.

    PubMed

    Vyas, Saurabh; Huang, He; Gale, John T; Sarma, Sridevi V; Montgomery, Erwin B

    2016-01-01

    Several theories posit increased Subthalamic Nucleus (STN) activity is causal to Parkinsonism, yet in our previous study we showed that activity from 113 STN neurons from two epilepsy patients and 103 neurons from nine Parkinson's disease (PD) patients demonstrated no significant differences in frequencies or in the coefficients of variation of mean discharge frequencies per 1-s epochs. We continued our analysis using point process modeling to capture higher order temporal dynamics; in particular, bursting, beta-band oscillations, excitatory and inhibitory ensemble interactions, and neuronal complexity. We used this analysis as input to a logistic regression classifier and were able to differentiate between PD and epilepsy neurons with an accuracy of 92%. We also found neuronal complexity, i.e., the number of states in a neuron's point process model, and inhibitory ensemble dynamics, which can be interpreted as a reduction in complexity, to be the most important features with respect to classification accuracy. Even in a dataset with no significant differences in firing rate, we observed differences between PD and epilepsy for other single-neuron measures. Our results suggest PD comes with a reduction in neuronal "complexity," which translates to a neuron's ability to encode information; the more complexity, the more information the neuron can encode. This is also consistent with studies correlating disease to loss of variability in neuronal activity, as the lower the complexity, the less variability.

  10. On Parallel Streams through the Mouse Dorsal Lateral Geniculate Nucleus.

    PubMed

    Denman, Daniel J; Contreras, Diego

    2016-01-01

    The mouse visual system is an emerging model for the study of cortical and thalamic circuit function. To maximize the usefulness of this model system, it is important to analyze the similarities and differences between the organization of all levels of the murid visual system with other, better studied systems (e.g., non-human primates and the domestic cat). While the understanding of mouse retina and cortex has expanded rapidly, less is known about mouse dorsal lateral geniculate nucleus (dLGN). Here, we study whether parallel processing streams exist in mouse dLGN. We use a battery of stimuli that have been previously shown to successfully distinguish parallel streams in other species: electrical stimulation of the optic chiasm, contrast-reversing stationary gratings at varying spatial phase, drifting sinusoidal gratings, dense noise for receptive field reconstruction, and frozen contrast-modulating noise. As in the optic nerves of domestic cats and non-human primates, we find evidence for multiple conduction velocity groups after optic chiasm stimulation. As in so-called "visual mammals", we find a subpopulation of mouse dLGN cells showing non-linear spatial summation. However, differences in stimulus selectivity and sensitivity do not provide sufficient basis for identification of clearly distinct classes of relay cells. Nevertheless, consistent with presumptively homologous status of dLGNs of all mammals, there are substantial similarities between response properties of mouse dLGN neurons and those of cats and primates.

  11. Glutamate and GABA modulate dopamine in the pedunculopontine tegmental nucleus.

    PubMed

    Steiniger, Björn; Kretschmer, Beate D

    2003-04-01

    The pedunculopontine tegmental nucleus (PPTg) has an important anatomical position connecting basal ganglia and limbic systems with motor execution structures in the pons and spinal cord. It receives glutamatergic and GABAergic input and has additional reciprocal connections with mesencephalic dopaminergic neurons, suggesting that the PPTg plays a key role in frontostriatal information processing. In vivo microdialysis in freely moving rats, in combination with behavioral analysis, was used in this study to investigate whether the dopaminergic input can be modulated at the level of the PPTg via N-methyl-D-aspartate (NMDA), alpha-amino-3-hydroxy-5-methyl-isoxazole-4-propionic acid (AMPA) or GABA(B) receptors. Stimulation of the GABA(B) receptor decreased dopamine release in the PPTg while that of the AMPA and NMDA receptors increased it. A time-related comparison of the effects of NMDA (0.75 and 1 mM) and AMPA (50 and 25 microM) revealed a more long-lasting effect after AMPA stimulation than after NMDA. However, only the infusion of the GABA(B) receptor agonist baclofen (100 and 200 microM) stimulated stereotyped behavior (e.g. sniffing, digging or head movements) and contralateral circling. This study clearly demonstrates that GABAergic as well as glutamatergic terminals in the PPTg are critically involved in the modulation of the dopamine system. Moreover, a decrease in PPTg dopamine via GABA(B) receptor stimulation seems to be behaviorally relevant.

  12. ELAV proteins along evolution: back to the nucleus?

    PubMed

    Colombrita, Claudia; Silani, Vincenzo; Ratti, Antonia

    2013-09-01

    The complex interplay of post-transcriptional regulatory mechanisms mediated by RNA-binding proteins (RBP) at different steps of RNA metabolism is pivotal for the development of the nervous system and the maintenance of adult brain activities. In this review, we will focus on the highly conserved ELAV gene family encoding for neuronal-specific RBPs which are necessary for proper neuronal differentiation and important for synaptic plasticity process. In the evolution from Drosophila to man, ELAV proteins seem to have changed their biological functions in relation to their different subcellular localization. While in Drosophila, they are localized in the nuclear compartment of neuronal cells and regulate splicing and polyadenylation, in mammals, the neuronal ELAV proteins are mainly present in the cytoplasm where they participate in regulating mRNA target stability, translation and transport into neurites. However, recent data indicate that the mammalian ELAV RBPs also have nuclear activities, similarly to their fly counterpart, being them able to continuously shuttle between the cytoplasm and the nucleus. Here, we will review and comment on all the biological functions associated with neuronal ELAV proteins along evolution and will show that the post-transcriptional regulatory network mediated by these RBPs in the brain is highly complex and only at an initial stage of being fully understood. This article is part of a Special Issue entitled 'RNA and splicing regulation in neurodegeneration'.

  13. Deuterium target data for precision neutrino-nucleus cross sections

    NASA Astrophysics Data System (ADS)

    Meyer, Aaron S.; Betancourt, Minerba; Gran, Richard; Hill, Richard J.

    2016-06-01

    Amplitudes derived from scattering data on elementary targets are basic inputs to neutrino-nucleus cross section predictions. A prominent example is the isovector axial nucleon form factor, FA(q2), which controls charged current signal processes at accelerator-based neutrino oscillation experiments. Previous extractions of FA from neutrino-deuteron scattering data rely on a dipole shape assumption that introduces an unquantified error. A new analysis of world data for neutrino-deuteron scattering is performed using a model-independent, and systematically improvable, representation of FA. A complete error budget for the nucleon isovector axial radius leads to rA2=0.46 (22 ) fm2 , with a much larger uncertainty than determined in the original analyses. The quasielastic neutrino-neutron cross section is determined as σ (νμn →μ-p )|Eν=1GeV=10.1 (0.9 )×10-39 cm2 . The propagation of nucleon-level constraints and uncertainties to nuclear cross sections is illustrated using MINERvA data and the GENIE event generator. These techniques can be readily extended to other amplitudes and processes.

  14. Deuterium target data for precision neutrino-nucleus cross sections

    NASA Astrophysics Data System (ADS)

    Hill, Richard; Meyer, Aaron; Betancourt, Minerba; Gran, Richard

    2016-09-01

    Amplitudes derived from scattering data on elementary targets are basic inputs to neutrino-nucleus cross section predictions. A prominent example is the isovector axial nucleon form factor, FA(q2) , which controls charged current signal processes at accelerator-based neutrino oscillation experiments. Previous extractions of FA from neutrino-deuteron scattering data rely on a dipole shape assumption that introduces an unquantified error. A new analysis of world data for neutrino-deuteron scattering is performed using a model-independent, and systematically improvable, representation of FA. A complete error budget for the nucleon isovector axial radius leads to rA2 = 0 . 46(22) fm2 , with a much larger uncertainty than determined in the original analyses. The quasielastic neutrino-neutron cross section is determined as σ(νμ n ->μ- p) |Eν = 1GeV = 10 . 1(0 . 9) ×10-39cm2 . The propagation of nucleon-level constraints and uncertainties to nuclear cross sections is illustrated using MINERvA data and the GENIE event generator. These techniques can be readily extended to other amplitudes and processes.

  15. Subthalamic nucleus stimulation affects incentive salience attribution in Parkinson's disease.

    PubMed

    Serranová, Tereza; Jech, Robert; Dušek, Petr; Sieger, Tomáš; Růžička, Filip; Urgošík, Dušan; Růžička, Evžen

    2011-10-01

    Deep brain stimulation (DBS) of the subthalamic nucleus (STN) can induce nonmotor side effects such as behavioral and mood disturbances or body weight gain in Parkinson's disease (PD) patients. We hypothesized that some of these problems could be related to an altered attribution of incentive salience (ie, emotional relevance) to rewarding and aversive stimuli. Twenty PD patients (all men; mean age ± SD, 58.3 ± 6 years) in bilateral STN DBS switched ON and OFF conditions and 18 matched controls rated pictures selected from the International Affective Picture System according to emotional valence (unpleasantness/pleasantness) and arousal on 2 independent visual scales ranging from 1 to 9. Eighty-four pictures depicting primary rewarding (erotica and food) and aversive fearful (victims and threat) and neutral stimuli were selected for this study. In the STN DBS ON condition, the PD patients attributed lower valence scores to the aversive pictures compared with the OFF condition (P < .01) and compared with controls (P < .01). The difference between the OFF condition and controls was less pronounced (P < .05). Furthermore, postoperative weight gain correlated with arousal ratings from the food pictures in the STN DBS ON condition (P < .05 compensated for OFF condition). Our results suggest that STN DBS increases activation of the aversive motivational system so that more relevance is attributed to aversive fearful stimuli. In addition, STN DBS-related sensitivity to food reward stimuli cues might drive DBS-treated patients to higher food intake and subsequent weight gain.

  16. Cortical connections of the rat lateral posterior thalamic nucleus.

    PubMed

    Kamishina, Hiroaki; Conte, William L; Patel, Sarika S; Tai, Rachel J; Corwin, James V; Reep, Roger L

    2009-04-06

    Spatial processing related to directed attention is thought to be mediated by a specific cortical-basal ganglia-thalamic-cortical network in the rat. Key components of this network are associative cortical areas medial agranular cortex (AGm) and posterior parietal cortex (PPC), dorsocentral striatum (DCS), and lateral posterior (LP) thalamic nucleus, all of which are interconnected. Previously, we found that thalamostriatal projections reaching DCS arise from separate populations of neurons of the mediorostral part of LP (LPMR). The far medial LPMR (fmLPMR) terminates in central DCS, a projection area of AGm, whereas central LPMR terminates in dorsal DCS, a projection area of PPC. This represents segregated regional convergence in DCS from different sources of thalamic and cortical inputs. In the present study, thalamocortical and corticothalamic projections arising from and terminating in LPMR and neighboring thalamic nuclei were studied by anterograde and retrograde tracing techniques in order to further understand the anatomical basis of this neural circuitry. A significant finding was that within LPMR, separate neuronal populations provide thalamic inputs to AGm or PPC and that these cortical areas project to separate regions in LPMR, from which they receive thalamic inputs. Other cortical areas adjacent to AGm or PPC also demonstrated reciprocal connections with LP or surrounding nuclei in a topographic manner. Our findings suggest that the cortical-basal ganglia-thalamic network mediating directed attention in the rat is formed by multiple loops, each having reciprocal connections that are organized in a precise and segregated topographical manner.

  17. Simultaneous electrophysiological recording and calcium imaging of suprachiasmatic nucleus neurons.

    PubMed

    Irwin, Robert P; Allen, Charles N

    2013-12-08

    Simultaneous electrophysiological and fluorescent imaging recording methods were used to study the role of changes of membrane potential or current in regulating the intracellular calcium concentration. Changing environmental conditions, such as the light-dark cycle, can modify neuronal and neural network activity and the expression of a family of circadian clock genes within the suprachiasmatic nucleus (SCN), the location of the master circadian clock in the mammalian brain. Excitatory synaptic transmission leads to an increase in the postsynaptic Ca(2+) concentration that is believed to activate the signaling pathways that shifts the rhythmic expression of circadian clock genes. Hypothalamic slices containing the SCN were patch clamped using microelectrodes filled with an internal solution containing the calcium indicator bis-fura-2. After a seal was formed between the microelectrode and the SCN neuronal membrane, the membrane was ruptured using gentle suction and the calcium probe diffused into the neuron filling both the soma and dendrites. Quantitative ratiometric measurements of the intracellular calcium concentration were recorded simultaneously with membrane potential or current. Using these methods it is possible to study the role of changes of the intracellular calcium concentration produced by synaptic activity and action potential firing of individual neurons. In this presentation we demonstrate the methods to simultaneously record electrophysiological activity along with intracellular calcium from individual SCN neurons maintained in brain slices.

  18. Deuterium target data for precision neutrino-nucleus cross sections

    DOE PAGES

    Meyer, Aaron S.; Betancourt, Minerba; Gran, Richard; ...

    2016-06-23

    Amplitudes derived from scattering data on elementary targets are basic inputs to neutrino-nucleus cross section predictions. A prominent example is the isovector axial nucleon form factor, FA(q2), which controls charged current signal processes at accelerator-based neutrino oscillation experiments. Previous extractions of FA from neutrino-deuteron scattering data rely on a dipole shape assumption that introduces an unquantified error. A new analysis of world data for neutrino-deuteron scattering is performed using a model-independent, and systematically improvable, representation of FA. A complete error budget for the nucleon isovector axial radius leads to rA2 = 0.46(22)fm2, with a much larger uncertainty than determined inmore » the original analyses. The quasielastic neutrino-neutron cross section is determined as σ(νμn → μ-p)|Ev=1GeV = 10.1(0.9)×10-39cm2. The propagation of nucleon-level constraints and uncertainties to nuclear cross sections is illustrated using MINERvA data and the GENIE event generator. Furthermore, these techniques can be readily extended to other amplitudes and processes.« less

  19. Multiquasiparticle states in the neutron-rich nucleus 174Tm

    NASA Astrophysics Data System (ADS)

    Hughes, R. O.; Lane, G. J.; Dracoulis, G. D.; Byrne, A. P.; Nieminen, P.; Watanabe, H.; Carpenter, M. P.; Chowdhury, P.; Janssens, R. V. F.; Kondev, F. G.; Lauritsen, T.; Seweryniak, D.; Zhu, S.

    2013-07-01

    Deep inelastic and transfer reactions with an 820-MeV, 136Xe beam and various ytterbium and lutetium targets have been employed to study high-spin structures in the neutron-rich thulium isotopes beyond 171Tm. Results in the doubly odd nucleus, 174Tm, include the identification of numerous new two- and four-quasiparticle intrinsic states including several isomers below 1 MeV, and the observation of the Kπ=4- ground state rotational band populated via direct decay from a τ=153(10)-μs, Kπ=14- isomer at 2092 keV. The 398-keV, M1 transition linking the isomer and ground state band is abnormally fast for a highly forbidden, ΔK=10 decay. This relative enhancement is explained in terms of mixing of the 13- level with the nearby 13- member of a Kπ=8- rotational band, with an interaction strength of V ≈ 1.4 keV. Multiquasiparticle calculations are compared with the observed states.

  20. Ice Nucleus Characteristics of Mount St. Helens Effluents

    SciTech Connect

    Schnell, R.C.; Pueschel, R.F.; Wellman, D.L.

    1982-12-20

    Aerosols were studied in situ and captured on membrane filters from an aircraft flown around Mount St. Helens during its phreatic period in April 1980. Bulk samples of volcanic ash were collected at ground level 120 km downwind on May 19, 1980 and reaerosolized in a laboratory in ash cloud simulation studies. The aerosol and/or ash samples were tested for ice nucleus (IN) activity using four different IN measurement systems (NCAR acoustical counter, bulk drop freezing, NCAR dynamic thermal diffusion chamber, and filter drop freezing). Although threshold IN activity was observed at -8/sup 0/C in bulk ash, in aerosols there were few IN active at temperatures warmer than -12/sup 0/C. At -12/sup 0/C, IN concentrations were less than 0.4 l/sup -1/ (400 m/sup -3/) even when the aerosol concentrations were as high as 3000 ..mu..g m/sup -3/. At aerosol concentrations of 500 ..mu..g m/sup -3/ and less, the IN content of the ash was below background threshold temperatures of -18/sup 0/C.