WorldWideScience

Sample records for nuclear transitions induced

  1. Nuclear effects in atomic transitions

    OpenAIRE

    Pálffy, Adriana

    2011-01-01

    Atomic electrons are sensitive to the properties of the nucleus they are bound to, such as nuclear mass, charge distribution, spin, magnetization distribution, or even excited level scheme. These nuclear parameters are reflected in the atomic transition energies. A very precise determination of atomic spectra may thus reveal information about the nucleus, otherwise hardly accessible via nuclear physics experiments. This work reviews theoretical and experimental aspects of the nuclear effects ...

  2. Laser induced nuclear reactions

    Science.gov (United States)

    Ledingham, Ken; McCanny, Tom; Graham, Paul; Fang, Xiao; Singhal, Ravi; Magill, Joe; Creswell, Alan; Sanderson, David; Allott, Ric; Neely, David; Norreys, Peter; Santala, Marko; Zepf, Matthew; Watts, Ian; Clark, Eugene; Krushelnick, Karl; Tatarakis, Michael; Dangor, Bucker; Machecek, Antonin; Wark, Justin

    1998-12-01

    Dramatic improvements in laser technology since 1984 have revolutionised high power laser technology. Application of chirped-pulse amplification techniques has resulted in laser intensities in excess of 1019W/cm2. In the mid to late eighties, C. K. Rhodes and K. Boyer discussed the possibility of shining laser light of this intensity onto solid surfaces and to cause nuclear transitions. In particular, irradiation of a uranium target could induce electro- and photofission in the focal region of the laser. In this paper it is shown that μCi of 62Cu can be generated via the (γ,n) reaction by a laser with an intensity of about 1019Wcm-2.

  3. Nuclear physics: Elusive transition spotted in thorium

    Science.gov (United States)

    Safronova, Marianna

    2016-05-01

    The highly precise atomic clocks used in science and technology are based on electronic transitions in atoms. The discovery of a nuclear transition in thorium-229 raises hopes of making nuclear clocks a reality. See Article p.47

  4. Gravitationally induced quantum transitions

    Science.gov (United States)

    Landry, A.; Paranjape, M. B.

    2016-06-01

    In this paper, we calculate the probability for resonantly inducing transitions in quantum states due to time-dependent gravitational perturbations. Contrary to common wisdom, the probability of inducing transitions is not infinitesimally small. We consider a system of ultracold neutrons, which are organized according to the energy levels of the Schrödinger equation in the presence of the Earth's gravitational field. Transitions between energy levels are induced by an oscillating driving force of frequency ω . The driving force is created by oscillating a macroscopic mass in the neighborhood of the system of neutrons. The neutron lifetime is approximately 880 sec while the probability of transitions increases as t2. Hence, the optimal strategy is to drive the system for two lifetimes. The transition amplitude then is of the order of 1.06 ×10-5, and hence with a million ultracold neutrons, one should be able to observe transitions.

  5. Gravitationally induced quantum transitions

    CERN Document Server

    Landry, A

    2016-01-01

    In this letter, we calculate the probability for resonantly induced transitions in quantum states due to time dependent gravitational perturbations. Contrary to common wisdom, the probability of inducing transitions is not infinitesimally small. We consider a system of ultra cold neutrons (UCN), which are organized according to the energy levels of the Schr\\"odinger equation in the presence of the earth's gravitational field. Transitions between energy levels are induced by an oscillating driving force of frequency $\\omega$. The driving force is created by oscillating a macroscopic mass in the neighbourhood of the system of neutrons. The neutrons decay in 880 seconds while the probability of transitions increase as $t^2$. Hence the optimal strategy is to drive the system for 2 lifetimes. The transition amplitude then is of the order of $1.06\\times 10^{-5}$ hence with a million ultra cold neutrons, one should be able to observe transitions.

  6. Pairing correlations and transitions in nuclear systems

    CERN Document Server

    Belic, A; Hjorth-Jensen, M

    2004-01-01

    We discuss several pairing-related phenomena in nuclear systems, ranging from superfluidity in neutron stars to the gradual breaking of pairs in finite nuclei. We describe recent experimental evidence that points to a relation between pairing and phase transitions (or transformations) in finite nuclear systems. A simple pairing interaction model is used in order to study and classify an eventual pairing phase transition in finite fermionic systems such as nuclei. We show that systems with as few as 10-16 fermions can exhibit clear features reminiscent of a phase transition.

  7. Event-by-Event Analysis of Proton-Induced Nuclear Multifragmentation Determination of Phase Transition Universality-Class in System with Extreme Finite-Size Constraints

    CERN Document Server

    Berkenbusch, M K; Dillman, K; Pratt, S; Beaulieu, L; Kwiatkowski, K K; Lefort, T; Hsi, W C; Viola, V E; Yennello, S J; Korteling, R G; Breuer, H

    2002-01-01

    A percolation model of nuclear fragmentation is used to interpret 10.2 GeV/c p+197Au multi-fragmentation data. Emphasis is put on finding signatures of a continuous nuclear matter phase transition in finite nuclear systems. Based on model calculations, corrections accounting for physical constraints of the fragment detection and sequential decay processes are derived. Strong circumstantial evidence for a continuous phase transition is found, and the values of two critical exponents, sigma = 0.5+-0.1 and tau = 2.35+-0.05, are extracted from the data. A critical temperature of T_c = 8.3+-0.2 MeV is found.

  8. Role of nuclear factor kappa B and reactive oxygen species in the tumor necrosis factor-a-induced epithelial-mesenchymal transition of MCF-7 cells

    Directory of Open Access Journals (Sweden)

    R. Dong

    2007-08-01

    Full Text Available The microenvironment of the tumor plays an important role in facilitating cancer progression and activating dormant cancer cells. Most tumors are infiltrated with inflammatory cells which secrete cytokines such as tumor necrosis factor-a (TNF-a. To evaluate the role of TNF-a in the development of cancer we studied its effects on cell migration with a migration assay. The migrating cell number in TNF-a -treated group is about 2-fold of that of the control group. Accordingly, the expression of E-cadherin was decreased and the expression of vimentin was increased upon TNF-a treatment. These results showed that TNF-a can promote epithelial-mesenchymal transition (EMT of MCF-7 cells. Further, we found that the expression of Snail, an important transcription factor in EMT, was increased in this process, which is inhibited by the nuclear factor kappa B (NFkB inhibitor aspirin while not affected by the reactive oxygen species (ROS scavenger N-acetyl cysteine. Consistently, specific inhibition of NFkB by the mutant IkBa also blocked the TNF-a-induced upregulation of Snail promoter activity. Thus, the activation of NFkB, which causes an increase in the expression of the transcription factor Snail is essential in the TNF-a-induced EMT. ROS caused by TNF-a seemed to play a minor role in the TNF-a-induced EMT of MCF-7 cells, though ROS per se can promote EMT. These findings suggest that different mechanisms might be responsible for TNF-a - and ROS-induced EMT, indicating the need for different strategies for the prevention of tumor metastasis induced by different stimuli.

  9. Nuclear shape transitions, level density, and underlying interactions

    CERN Document Server

    Karampagia, S

    2016-01-01

    The configuration interaction approach to nuclear structure uses the effective Hamiltonian in a finite orbital space. The various parts of this Hamiltonian and their interplay are responsible for specific features of physics including the shape of the mean field and level density. This interrelation is not sufficiently understood. We intend to study phase transitions between spherical and deformed shapes driven by different parts of the nuclear Hamiltonian and to establish the presence of the collective enhancement of the nuclear level density by varying the shell-model matrix elements. Varying the interaction matrix elements we define, for nuclei in the sd and pf shells, the sectors with spherical and deformed shapes. Using the moments method that does not require the full diagonalization we relate the shape transitions with the corresponding level density. Enhancement of the level density in the low-energy part of the spectrum is observed in clear correlation with a deformation phase transition induced main...

  10. Nuclear Binding Near a Quantum Phase Transition

    Science.gov (United States)

    Elhatisari, Serdar; Li, Ning; Rokash, Alexander; Alarcón, Jose Manuel; Du, Dechuan; Klein, Nico; Lu, Bing-nan; Meißner, Ulf-G.; Epelbaum, Evgeny; Krebs, Hermann; Lähde, Timo A.; Lee, Dean; Rupak, Gautam

    2016-09-01

    How do protons and neutrons bind to form nuclei? This is the central question of ab initio nuclear structure theory. While the answer may seem as simple as the fact that nuclear forces are attractive, the full story is more complex and interesting. In this work we present numerical evidence from ab initio lattice simulations showing that nature is near a quantum phase transition, a zero-temperature transition driven by quantum fluctuations. Using lattice effective field theory, we perform Monte Carlo simulations for systems with up to twenty nucleons. For even and equal numbers of protons and neutrons, we discover a first-order transition at zero temperature from a Bose-condensed gas of alpha particles (4He nuclei) to a nuclear liquid. Whether one has an alpha-particle gas or nuclear liquid is determined by the strength of the alpha-alpha interactions, and we show that the alpha-alpha interactions depend on the strength and locality of the nucleon-nucleon interactions. This insight should be useful in improving calculations of nuclear structure and important astrophysical reactions involving alpha capture on nuclei. Our findings also provide a tool to probe the structure of alpha cluster states such as the Hoyle state responsible for the production of carbon in red giant stars and point to a connection between nuclear states and the universal physics of bosons at large scattering length.

  11. Nuclear binding near a quantum phase transition

    CERN Document Server

    Elhatisari, Serdar; Rokash, Alexander; Alarcón, Jose Manuel; Du, Dechuan; Klein, Nico; Lu, Bing-nan; Meißner, Ulf-G; Epelbaum, Evgeny; Krebs, Hermann; Lähde, Timo A; Lee, Dean; Rupak, Gautam

    2016-01-01

    How do protons and neutrons bind to form nuclei? This is the central question of ab initio nuclear structure theory. While the answer may seem as simple as the fact that nuclear forces are attractive, the full story is more complex and interesting. In this work we present numerical evidence from ab initio lattice simulations showing that nature is near a quantum phase transition, a zero-temperature transition driven by quantum fluctuations. Using lattice effective field theory, we perform Monte Carlo simulations for systems with up to twenty nucleons. For even and equal numbers of protons and neutrons, we discover a first-order transition at zero temperature from a Bose-condensed gas of alpha particles (4He nuclei) to a nuclear liquid. Whether one has an alpha-particle gas or nuclear liquid is determined by the strength of the alpha-alpha interactions, and we show that the alpha-alpha interactions depend on the strength and locality of the nucleon-nucleon interactions. The existence of the nearby first-order ...

  12. Mutual control of X-rays and nuclear transitions

    Energy Technology Data Exchange (ETDEWEB)

    Gunst, Jonas Friedrich

    2015-12-14

    In the course of this Thesis the mutual control between X-rays and nuclear transitions is investigated theoretically. In the first Part, we study the nuclear photoexcitation with the highly brilliant and coherent X-ray free-electron lasers (XFELs). Apart from amplifying the direct resonant interaction with nuclear transitions, the super-intense XFEL can produce new states of matter like cold, high-density plasmas where secondary nuclear excitation channels may come into play, e.g., nuclear excitation by electron capture (NEEC). Our results predict that in the case of {sup 57}Fe targets secondary NEEC can be safely neglected, whereas it is surprisingly the dominating contribution (in comparison to the direct photoexcitation) for the XFEL-induced {sup 93m}Mo isomer triggering. Based on these case studies, we elaborate a general set of criteria to identify the prevailing excitation channel for a certain nuclear isotope. These criteria may be most relevant for future nuclear resonance experiments at XFEL facilities. On the opposite frontier, the interplay between single X-ray photons and nuclear transitions offer potential storage and processing applications for information science in their most compact form. In the second Part of this Thesis, we show that nuclear forward scattering off {sup 57}Fe targets can be employed to process polarization-encoded single X-rays via timed magnetic field rotations. Apart from the realization of logical gates with X-rays, the polarization encoding is used to design an X-ray quantum eraser scheme where the interference between scattering paths can be switched off and on in a controlled manner. Such setups may advance time-energy complementarity tests to so far unexplored parameter regimes, e.g., to the domain of X-ray quanta.

  13. Liquid-Gas Phase Transition in Nuclear Equation of State

    CERN Document Server

    Lee, S J

    1997-01-01

    A canonical ensemble model is used to describe a caloric curve of nuclear liquid-gas phase transition. Allowing a discontinuity in the freeze out density from one spinodal density to another for a given initial temperature, the nuclear liquid-gas phase transition can be described as first order. Averaging over various freeze out densities of all the possible initial temperatures for a given total reaction energy, the first order characteristics of liquid-gas phase transition is smeared out to a smooth transition. Two experiments, one at low beam energy and one at high beam energy show different caloric behaviors and are discussed.

  14. Laser induced nuclear waste transmutation

    CERN Document Server

    Hirlimann, Charles

    2016-01-01

    When producing electricity that collects the mass energy that is available at the time of the induced disintegration of radioactive elements, other unstable elements are produced with half-life span durations ranging from less than one second to hundreds of thousands of years and which are considered as waste. Managing nuclear waste with a half-life of less than 30 years is an easy task, as our societies clearly know how to keep buildings safe for more than a century, the time it takes for the activity to be divided by a factor of 8. High-activity, long-lasting waste that can last for thousands of years or even longer, up to geological time laps, cannot be taken care of for such long durations. Therefore, these types of waste are socially unacceptable; nobody wants to leave a polluted planet to descendants.

  15. Experimental observables on nuclear liquid gas phase transition

    CERN Document Server

    Ma, Y G

    2006-01-01

    Progress on nuclear liquid gas phase transition (LGPT) or critical behavior has been simply reviewed and some signals of LGPT in heavy ion collisions, especially in NIMROD data, are focused. These signals include the power-law charge distribution, the largest fluctuation of the fragment observables, the nuclear Zipf law, caloric curve and critical exponent analysis etc.

  16. Nuclear Liquid-Gas Phase Transition: Experimental Signals

    Science.gov (United States)

    D'Agostino, M.; Bruno, M.; Gulminelli, F.; Cannata, F.; Chomaz, Ph.; Casini, G.; Geraci, E.; Gramegna, F.; Moroni, A.; Vannini, G.

    2005-03-01

    The connection between the thermodynamics of charged finite nuclear systems and the asymptotically measured partitions in heavy ion collisions is discussed. Different independent signals compatible with a liquid-to-gas-like phase transition are reported. In particular abnormally large fluctuations in the measured observables are presented as a strong evidence of a first order phase transition with negative heat capacity.

  17. Nuclear liquid-gas phase transition: Experimental signals

    Energy Technology Data Exchange (ETDEWEB)

    D' Agostino, M. [Dipartimento di Fisica and INFN, Bologna (Italy); Bruno, M. [Dipartimento di Fisica and INFN, Bologna (Italy); Gulminelli, F. [LPC Caen (IN2P3-CNRS/ISMRA et Universite), F-14050 Caen Cedex (France); Cannata, F. [Dipartimento di Fisica and INFN, Bologna (Italy); Chomaz, Ph. [GANIL, DSM-CEA/IN2P3-CNRS (France); Casini, G. [INFN Sezione di Firenze (Italy); Geraci, E. [Dipartimento di Fisica and INFN, Bologna (Italy); Gramegna, F. [INFN Laboratorio Nazionale di Legnaro (Italy); Moroni, A. [Dipartimento di Fisica and INFN, Milano (Italy); Vannini, G. [Dipartimento di Fisica and INFN, Bologna (Italy)

    2005-03-07

    The connection between the thermodynamics of charged finite nuclear systems and the asymptotically measured partitions in heavy ion collisions is discussed. Different independent signals compatible with a liquid-to-gas-like phase transition are reported. In particular abnormally large fluctuations in the measured observables are presented as a strong evidence of a first order phase transition with negative heat capacity.

  18. Problem of phase transitions in nuclear structure

    Energy Technology Data Exchange (ETDEWEB)

    Scharff-Goldhaber, G

    1980-01-01

    Phase transitions between rotational and vibrational nuclei are discussed from the point of view of the variable moment of inertia model. A three-dimensional plot of the ground-state moments of inertia of even-even nuclei vs N and Z is shown. 3 figures. (RWR)

  19. Recent progress of nuclear liquid gas phase transition

    Institute of Scientific and Technical Information of China (English)

    MA Yu-Gang; SHEN Wen-Qing

    2004-01-01

    Recent progress on nuclear liquid gas phase transition (LGPT) has been reviewed, especially for the signals of LGPT in heavy ion collisions. These signals include the power-law charge distribution, cluster emission rate, nuclear Zipf law, bimodality, the largest fluctuation of the fragments, △ -scaling, caloric curve, phase coexistence diagram, critical temperature, critical exponent analysis, negative specific heat capacity and spinodal instability etc. The systematic works of the authors on experimental and theoretical LGPT are also introduced.

  20. Nuclear effects in deep inelastic scattering and transition region

    CERN Document Server

    Kumano, S

    2016-01-01

    We discuss nuclear effects on neutrino-nuclear interactions in a wide kinematical range from shallow to deep inelastic scattering (DIS) region. There is necessity from neutrino communities to have precise neutrino-nucleus cross sections within several percent order for future measurements on neutrino oscillations and leptonic CP violation. We try to create a model to calculate neutrino cross sections in the wide kinematical range, from quasi-elastic scattering and resonance productions to the DIS. In this article, nuclear modifications of structure functions are mainly discussed, and a possible extension to the $Q^2 \\to 0$ region is explained. We also comment on the transition region between baryon resonances and the DIS. There are ongoing experimental efforts on nuclear modifications of structure functions or parton distribution functions such as by pA reactions at RHIC and LHC, Drell-Yan measurements at Fermilab, Miner$\

  1. Thermally induced morphological transition of silver fractals

    DEFF Research Database (Denmark)

    Solov'yov, Ilia; Solov'yov, Andrey; Kébaili, Nouari;

    2014-01-01

    We present both experimental and theoretical study of thermally induced morphological transition of silver nanofractals. Experimentally, those nanofractals formed from deposition and diffusion of preformed silver clusters on cleaved graphite surfaces exhibit dendritic morphologies that are highly...

  2. Thermally induced morphological transition of silver fractals

    DEFF Research Database (Denmark)

    Solov'yov, Ilia; Solov'yov, Andrey; Kébaili, Nouari

    2014-01-01

    We present both experimental and theoretical study of thermally induced morphological transition of silver nanofractals. Experimentally, those nanofractals formed from deposition and diffusion of preformed silver clusters on cleaved graphite surfaces exhibit dendritic morphologies that are highly...

  3. Electromagetically induced transparency with nuclear spin.

    Science.gov (United States)

    Lu, Mei-Ju; Weinstein, Jonathan D

    2010-03-01

    We report the observation of electromagnetically induced transparency in a sample of cryogenically cooled ground-state atomic ytterbium ((1)S(0)). The transparency is produced due to coherence between the optical field and the nuclear spin state of the (173)Yb nucleus. Because the nuclear spin states interact very weakly with their environment, they are resistant to decoherence due to inelastic collisions and inhomogenous fields. Consequently, atomic ensembles of pure nuclear spin states may be a superior medium for a variety of nonlinear optics and quantum information experiments.

  4. Dynamic Analysis of Nuclear Waste Generation Based on Nuclear Fuel Cycle Transition Scenarios

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, S. R. [University of Science and Technology, Daejeon (Korea, Republic of); Ko, W. I. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    According to the recommendations submitted by the Public Engagement Commission on Spent Nuclear Fuel Management (PECOS), the government was advised to pick the site for an underground laboratory and interim storage facilities before the end of 2020 followed by the related research for permanent and underground disposal of spent fuel after 10 years. In the middle of the main issues, the factors of environmentally friendly and safe way to handle nuclear waste are inextricable from nuclear power generating nation to ensure the sustainability of nuclear power. For this purposes, the closed nuclear fuel cycle has been developed regarding deep geological disposal, pyroprocessing, and burner type sodium-cooled fast reactors (SFRs) in Korea. Among two methods of an equilibrium model and a dynamic model generally used for screening nuclear fuel cycle system, the dynamic model is more appropriate to envisage country-specific environment with the transition phase in the long term and significant to estimate meaningful impacts based on the timedependent behavior of harmful wastes. This study aims at analyzing the spent nuclear fuel generation based on the long-term nuclear fuel cycle transition scenarios considered at up-to-date country specific conditions and comparing long term advantages of the developed nuclear fuel cycle option between once-through cycle and Pyro-SFR cycle. In this study, a dynamic analysis was carried out to estimate the long-term projection of nuclear electricity generation, installed capacity, spent nuclear fuel arising in different fuel cycle scenarios based on the up-to-date national energy plans.

  5. Atomic clock with nuclear transition: current status in TU Wien

    OpenAIRE

    Kazakov, G. A.; Schreitl, M.; Winkler, G.; Sterba, J. H.; Steinhauser, G; Schumm, T.

    2011-01-01

    The nucleus of 229Thorium presents a unique isomer state of very low energy and long lifetime, current estimates are around 7.8 eV and seconds to hours respectively. This nuclear transitions therefore is a promising candidate for a novel type of frequency standard and several groups worldwide have set out to investigate this system. Our aim is to construct a "solid state nuclear clock", i.e. a frequency standard where Thorium ions are implanted into Calciumfluoride crystals transparent in vac...

  6. Nuclear Matter Phase Transition in Infinite and Finite Systems

    Science.gov (United States)

    Terranova, S.; Bonasera, A.

    2005-04-01

    A new "semiclassical" model of the nuclear matter, composed of u, d colored quarks, is proposed. The approach, named Constrained Molecular Dynamics (CoMD) is based on the molecular dynamics simulation of the quarks, which interact through the Richardson's potential, and on a constraint due to Pauli blocking. With a suitable choice of the quark masses, some possible Equation of State (EOS) of the nuclear matter, at temperature equal to zero and finite baryon density, are obtained. These equations of state, not only present some known properties of the nuclear matter, as the Quark-Gluon Plasma (QGP) phase transition, but also shown the existence of a new state, the Exotic Color Clustering (ECC) state, in which cluster of quarks with the same color are formed. Some new quantities, "indicators" of the phase transition, are introduced: three order parameters, Mc2, Mc3, Mc4 defined trough the Gell-Mann matrices λα, and the lifetime of the J/Ψ particle. The behavior of the J/Ψ particle is studied also in the "finite" systems, obtained by expanding the corresponding "infinite" systems. It seems that the dynamics and the finite size effects do not wash completely the phase transition occurred in infinite systems, and the J/Ψ particle is still a good signature.

  7. Nuclear clocks based on resonant excitation of gamma-transitions

    CERN Document Server

    Peik, Ekkehard

    2015-01-01

    We review the ideas and concepts for a clock that is based on a radiative transition in the nucleus rather than in the electron shell. This type of clock offers advantages like an insensitivity against field-induced systematic frequency shifts and the opportunity to obtain high stability from interrogating many nuclei in the solid state. Experimental work concentrates on the low-energy (about 8 eV) isomeric transition in Th-229. We review the status of the experiments that aim at a direct optical observation of this transition and outline the plans for high-resolution laser spectroscopy experiments.

  8. Nuclear dynamics induced by antiprotons

    CERN Document Server

    Feng, Zhao-Qing

    2015-01-01

    Reaction dynamics in collisions of antiprotons on nuclei is investigated within the Lanzhou quantum molecular dynamics model. The reaction channels of elastic scattering, annihilation, charge exchange and inelastic collisions of antiprotons on nucleons have been included in the model. Dynamics on particle production, in particular pions, kaons, antikaons and hyperons, is investigated in collisions of $\\overline{p}$ on $^{12}$C, $^{20}$Ne, $^{40}$Ca and $^{181}$Ta from a low to high incident momenta. It is found that the annihilations of $\\overline{p}$ on nucleons are of importance on the dynamics of particle production in phase space. Hyperons are mainly produced via meson induced reactions on nucleons and strangeness exchange collisions, which lead to the delayed emission in antiproton-nucleus collisions.

  9. Nuclear response functions for the N-N*(1440) transition

    CERN Document Server

    Alvarez-Ruso, L; Donnelly, T W; Molinari, A

    2003-01-01

    Parity-conserving and -violating response functions are computed for the inclusive electroexcitation of the N*(1440)(Roper) resonance in nuclear matter modeled as a relativistic Fermi gas. Using various empirical parameterizations and theoretical models of the N-N*(1440) transition form factors, the sensitivity of the response functions to details of the structure of the Roper resonance is investigated. The possibility of disentangling this resonance from the contribution of Delta electroproduction in nuclei is addressed. Finally, the contributions of the Roper resonance to the longitudinal scaling function and to the Coulomb sum rule are also explored.

  10. The Effect of Tripterygium Wilfordii Monomer T4 on Rat Spermatid Nuclear Protein Transition

    Institute of Scientific and Technical Information of China (English)

    戴文平; 刘平; 陈啸梅; 薛社普

    1996-01-01

    Rat testis elongating spermatids and epididymal sperms were collected after 7 weeks of treatment with Tripterygium wilfordii monomer T4. Total nuclear basic protein (TNBP) was extracted from the elongating spermatid nuclei and the sperm nuclei isolated by sonication. Polyacrylamide gel electrophoresis has beep used to separate the TNBP and individual proteins were quantified by scanning microdensitometry. It was found that the content of protamine was reduced and the TH (Total Histones) /RP (Rat Protamine) ratios were increased following treatment in the testis elongating spermatids, and same result was found in the epididymal sperms. These results suggest that the interruption of nuclear protein transition of testis spermatids induced by T4 might cause aberrant epididymal sperm nuclear protein and lead to infertility. The relationship between protamine and fertility was discussed.

  11. Contemporary research of dynamically induced phase transitions

    Science.gov (United States)

    Hull, L. M.

    2017-01-01

    Dynamically induced phase transitions in metals, within the present discussion, are those that take place within a time scale characteristic of the shock waves and any reflections or rarefactions involved in the loading structure along with associated plastic flow. Contemporary topics of interest include the influence of loading wave shape, the effect of shear produced by directionality of the loading relative to the sample dimensions and initial velocity field, and the loading duration (kinetic effects, hysteresis) on the appearance and longevity of a transformed phase. These topics often arise while considering the loading of parts of various shapes with high explosives, are typically two or three-dimensional, and are often selected because of the potential of the transformed phase to significantly modify the motion. In this paper, we look at current work on phase transitions in metals influenced by shear reported in the literature, and relate recent work conducted at Los Alamos on iron's epsilon phase transition that indicates a significant response to shear produced by reflected elastic waves. A brief discussion of criteria for the occurrence of stress induced phase transitions is provided. Closing remarks regard certain physical processes, such as fragmentation and jet formation, which may be strongly influenced by phase transitions.

  12. Nuclear apoptosis induced by isolated mitochondria

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    We isolated and purified mitochondria from mouse livers and spinach leaves. When added into egg extracts of Xenopus laevis, they caused nuclei of mouse liver to undergo apoptotic changes. Chromatin condensation, margination and DNA ladder were observed. After incubating isolated mitochondria in some hypotonic solutions, and centrifuging these mixtures at high speed, we got mitochondrial supernatants. It was found that in the absence of cytosolic factor, the supernatant alone was able to induce apoptotic changes in nuclei. The effective components were partly of protein. DNA fragmentation was partly inhibited by caspase inhibitors AC-DEVD-CHO and AC-YVADCHO. Meanwhile, caspase inhibitors fully blocked chromatin condensation. Primary characterization of the nuclear endonuclease(s) induced by mitochondrial supernatants was also conducted. It was found that this endonuclease is different from endonuclease G, cytochrome c-induced nuclease, or Ca2+-activated endonuclease.

  13. Nuclear effects in neutrino induced reactions

    CERN Document Server

    Vacas, M J Vicente; Geng, L S; Nieves, J; Valverde, M; Hirenzaki, S

    2008-01-01

    We discuss the relevance of nuclear medium effects in the analysis of some low and medium energy neutrino reactions of current interest. In particular, we study the Quasi-Elastic (QE) process, where RPA correlations and Final State Interactions (FSI) are shown to play a crucial role. We have also investigated the neutrino induced coherent pion production. We find a strong reduction of the cross section due to the distortion of the pion wave function and the modification of the production mechanisms in the nucleus. The sensitivity of the results to the axial $N\\Delta$ coupling $C_5^A(0)$ has been also investigated.

  14. Structure of nuclear transition matrix elements for neutrinoless double- decay

    Indian Academy of Sciences (India)

    P K Rath

    2010-08-01

    The structure of nuclear transition matrix elements (NTMEs) required for the study of neutrinoless double- decay within light Majorana neutrino mass mechanism is disassembled in the PHFB model. The NTMEs are calculated using a set of HFB intrinsic wave functions, the reliability of which has been previously established by obtaining an overall agreement between the theoretically calculated spectroscopic properties and the available experimental data. Presently, we study the role of short-range correlations, radial evolution of NTMEs and deformation effects due to quadrupolar correlations. In addition, limits on effective light neutrino mass $\\langle m_{} \\rangle$ are extracted from the observed limits on half-lives $T_{1/2}^{0}$ of neutrinoless double- decay.

  15. Geometry induced entanglement transitions in nanostructures

    CERN Document Server

    Coe, J P; D'Amico, I

    2010-01-01

    We model quantum dot nanostructures using a one-dimensional system of two interacting electrons. We show that strong and rapid variations may be induced in the spatial entanglement by varying the nanostructure geometry. We investigate the position-space information entropy as an indicator of the entanglement in this system. We also consider the expectation value of the Coulomb interaction and the ratio of this expectation to the expectation of the confining potential and their link to the entanglement. We look at the first derivative of the entanglement and the position-space information entropy to infer information about a possible quantum phase transition.

  16. Shear induced phase transitions induced in edible fats

    Science.gov (United States)

    Mazzanti, Gianfranco; Welch, Sarah E.; Marangoni, Alejandro G.; Sirota, Eric B.; Idziak, Stefan H. J.

    2003-03-01

    The food industry crystallizes fats under different conditions of temperature and shear to obtain products with desired crystalline phases. Milk fat, palm oil, cocoa butter and chocolate were crystallized from the melt in a temperature controlled Couette cell. Synchrotron x-ray diffraction studies were conducted to examine the role of shear on the phase transitions seen in edible fats. The shear forces on the crystals induced acceleration of the alpha to beta-prime phase transition with increasing shear rate in milk fat and palm oil. The increase was slow at low shear rates and became very strong above 360 s-1. In cocoa butter the acceleration between beta-prime-III and beta-V phase transition increased until a maximum of at 360 s-1, and then decreased, showing competition between enhanced heat transfer and viscous heat generation.

  17. Liquid-Gas Phase Transition for Asymmetric Nuclear Matter in the Zimanyi-Moszkowski Model

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xu-Ming; QIAN Wei-Liang; SU Ru-Keng

    2004-01-01

    By using the improved Zimanyi-Moszkowski (ZM) model including the freedom of nucleons, σ mesons, ω mesons and ρ mesons, we investigate the liquid-gas phase transition for asymmetric nuclear matter. It is found that the phase transition for asymmetric nuclear matter in the improved ZM model with the isospin vector ρ meson degree of freedom is well defined. The binodal surface, which is essential in the study of the phase transition process, is addressed.

  18. Nuclear fission and neutron-induced fission cross-sections

    CERN Document Server

    James, G D; Michaudon, A; Michaudon, A; Cierjacks, S W; Chrien, R E

    2013-01-01

    Nuclear Fission and Neutron-Induced Fission Cross-Sections is the first volume in a series on Neutron Physics and Nuclear Data in Science and Technology. This volume serves the purpose of providing a thorough description of the many facets of neutron physics in different fields of nuclear applications. This book also attempts to bridge the communication gap between experts involved in the experimental and theoretical studies of nuclear properties and those involved in the technological applications of nuclear data. This publication will be invaluable to those interested in studying nuclear fis

  19. Nuclear Excitation by Electronic Transition of U-235

    Energy Technology Data Exchange (ETDEWEB)

    Chodash, Perry Adam [Univ. of California, Berkeley, CA (United States)

    2015-07-14

    Nuclear excitation by electronic transition (NEET) is a rare nuclear excitation that is theorized to occur in numerous isotopes. One isotope in particular, 235U, has been studied several times over the past 40 years and NEET of 235U has never been conclusively observed. These past experiments generated con icting results with some experiments claiming to observe NEET of 235U and others setting limits for the NEET rate. This dissertation discusses the latest attempt to measure NEET of 235U. If NEET of 235U were to occur, 235mU would be created. 235mU decays by internal conversion with a decay energy of 76 eV and a half-life of 26 minutes. A pulsed Nd:YAG laser operating at 1064 nm with a pulse energy of 789 mJ and a pulse width of 9 ns was used to generate a uranium plasma. The plasma was captured on a catcher plate and electrons emitted from the catcher plate were accelerated and focused onto a microchannel plate detector. A decay of 26 minutes would suggest the creation of 235mU and the possibility that NEET occurred. However, measurements performed using a variety of uranium targets spanning depleted uranium up to 99.4% enriched uranium did not observe a 26 minute decay. Numerous other decays were observed with half-lives ranging from minutes up to hundreds of minutes. While NEET of 235U was not observed during this experiment, an upper limit for the NEET rate of 235U was determined. In addition, explanations for the con icting results from previous experiments are given. Based on the results of this experiment and the previous experiments looking for NEET of 235U, it is likely that NEET of 235U has never been observed.

  20. Stress induced phase transitions in silicon

    Science.gov (United States)

    Budnitzki, M.; Kuna, M.

    2016-10-01

    Silicon has a tremendous importance as an electronic, structural and optical material. Modeling the interaction of a silicon surface with a pointed asperity at room temperature is a major step towards the understanding of various phenomena related to brittle as well as ductile regime machining of this semiconductor. If subjected to pressure or contact loading, silicon undergoes a series of stress-driven phase transitions accompanied by large volume changes. In order to understand the material's response for complex non-hydrostatic loading situations, dedicated constitutive models are required. While a significant body of literature exists for the dislocation dominated high-temperature deformation regime, the constitutive laws used for the technologically relevant rapid low-temperature loading have severe limitations, as they do not account for the relevant phase transitions. We developed a novel finite deformation constitutive model set within the framework of thermodynamics with internal variables that captures the stress induced semiconductor-to-metal (cd-Si → β-Si), metal-to-amorphous (β-Si → a-Si) as well as amorphous-to-amorphous (a-Si → hda-Si, hda-Si → a-Si) transitions. The model parameters were identified in part directly from diamond anvil cell data and in part from instrumented indentation by the solution of an inverse problem. The constitutive model was verified by successfully predicting the transformation stress under uniaxial compression and load-displacement curves for different indenters for single loading-unloading cycles as well as repeated indentation. To the authors' knowledge this is the first constitutive model that is able to adequately describe cyclic indentation in silicon.

  1. Pumping of nuclear spins by optical excitation of spin-forbidden transitions in a quantum dot.

    Science.gov (United States)

    Chekhovich, E A; Makhonin, M N; Kavokin, K V; Krysa, A B; Skolnick, M S; Tartakovskii, A I

    2010-02-12

    We demonstrate that efficient optical pumping of nuclear spins in semiconductor quantum dots (QDs) can be achieved by resonant pumping of optically forbidden transitions. This process corresponds to one-to-one conversion of a photon absorbed by the dot into a polarized nuclear spin, and also has potential for initialization of hole spin in QDs. We find that by employing this spin-forbidden process, nuclear polarization of 65% can be achieved, markedly higher than from pumping the allowed transition, which saturates due to the low probability of electron-nuclear spin flip-flop.

  2. Dissociative photoionization of molecular hydrogen. A joint experimental and theoretical study of the electron-electron correlations induced by XUV photoionization and nuclear dynamics on IR-laser dressed transition states

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, Andreas

    2015-01-13

    In this thesis, the dissociative single-ionization of molecular hydrogen is investigated in a kinematically complete experiment by employing extreme ultraviolet attosecond pulse trains and infrared femtosecond laser pulses. Induced by the absorption of a single XUV photon, a pronounced energy-dependent asymmetry of the relative emission direction of the photoelectron and the ion is observed. The asymmetry pattern is explained in terms of an interference of two ionization pathways involving a doubly-excited state. This interpretation is validated by a semi-classical model which only takes the nuclear motion into account. Using this model and the observed asymmetry, it is furthermore possible to disentangle the two dissociation pathways which allows for the determination of the autoionization lifetime of the contributing doubly-excited state as a function of the internuclear distance. Moreover, using a pump-probe experiment the dissociation dynamics of molecular hydrogen is investigated. A time-delay dependent momentum distribution of the fragments is observed. With a combined quantum mechanical and semi-classical approach the mechanism giving rise to the observed time-dependence is identified in terms of an intuitive elevator mechanism.

  3. Population and coherence transfer in half-integer quadrupolar spin systems induced by simultaneous rapid passages of the satellite transitions: A static and spinning single crystal nuclear magnetic resonance study

    Science.gov (United States)

    Schäfer, Hartmut; Iuga, Dinu; Verhagen, Rieko; Kentgens, Arno P. M.

    2001-02-01

    We have recently shown that utilizing double frequency sweeps (DFSs) instead of pulses can lead to increased efficiencies in population and coherence transfer in half-integer quadrupolar spin systems. Cosine modulation of the carrier amplitude corresponds to the simultaneous irradiation of two frequencies symmetrically around the rf-carrier frequency. Convergent or divergent DFSs can be generated by appropriate time-dependent cosine modulation of the rf field. Population and coherence transfer induced by sweeping the modulation frequency through the quadrupolar satellite transitions is investigated in detail. The time dependence of such passages determines the adiabaticity of the transfer processes. Insight into the involved spin dynamics is of utmost importance in the design and optimization of experiments based on amplitude modulation, such as DFS enhanced multiple-quantum magic angle spanning, where multiple to single-quantum conversion is performed by a DFS. Vega and co-workers have provided a theoretical basis of adiabatic coherence transfer in spin-3/2 systems induced by the combined action of simple time independent cosine amplitude modulation (CAM) of the rf field and sample spinning [Madhu et al., J. Chem. Phys. 112, 2377 (2000)]. In our report we will extend this theory to DFS induced adiabatic transfer phenomena in spin-3/2 and spin-5/2 systems. A fully analytical description will be presented covering the whole adiabaticity range resulting in an accurate description of actual experiments. In this context it will be shown that both population and coherence transfer are governed by the same principles and one unique adiabaticity parameter for each pair of spectral satellites. The transfer phenomena derived for spin-3/2 systems will be studied and quantified experimentally for 23Na in a single crystal of NaNO3. In a static and spinning sample the combination with DFS and CAM irradiation will be studied showing the equivalence of the transfer in all these

  4. Waveguide transition with vacuum window for multiband dynamic nuclear polarization systems

    DEFF Research Database (Denmark)

    Rybalko, Oleksandr; Bowen, Sean; Zhurbenko, Vitaliy

    2016-01-01

    A low loss waveguide transition section and oversized microwave vacuum window covering several frequency bands (94 GHz, 140 GHz, 188 GHz) is presented. The transition is compact and was optimized for multiband Dynamic Nuclear Polarization (DNP) systems in a full-wave simulator. The window is more...

  5. 5th International Workshop on Desorption Induced by Electronic Transitions

    CERN Document Server

    Jennison, Dwight R; Stechel, Ellen B; DIET V; Desorption induced by electronic transitions

    1993-01-01

    This volume in the Springer Series on Surface Sciences presents a recent account of advances in the ever-broadening field of electron-and photon-stimulated sur­ face processes. As in previous volumes, these advances are presented as the proceedings of the International Workshop on Desorption Induced by Electronic Transitions; the fifth workshop (DIET V) was held in Taos, New Mexico, April 1-4, 1992. It will be abundantly clear to the reader that "DIET" is not restricted to desorption, but has for several years included photochemistry, non-thermal surface modification, exciton self-trapping, and many other phenomena that are induced by electron or photon bombardment. However, most stimulated surface processes do share a common physics: initial electronic excitation, localization of the excitation, and conversion of electronic energy into nuclear kinetic energy. It is the rich variation of this theme which makes the field so interesting and fruitful. We have divided the book into eleven parts in orde...

  6. Glass transition temperatures of epoxy resins by pulsed nuclear magnetic resonance spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Rutenberg, A.C.; Dorsey, G.F.; Peck, C.G.

    1976-04-21

    Pulsed nuclear magnetic resonance spectroscopy has been used to measure the glass transition temperatures of cured epoxy resins. These measurements make it possible to monitor the cure and determine the glass transition temperature as a function of the curing conditions and the concentration of the components. Knowledge of the glass transition temperature of the cured epoxies allows screening of them for a number of uses, including adhesives and coatings operations.

  7. Kinetics of shock-induced polymorphic phase transitions

    Energy Technology Data Exchange (ETDEWEB)

    Hayes, D.B.

    1976-01-01

    Shock-loading induces polymorphic phase transitions in some solids if the pressure exceeds that at which phase transition occurs under quasi-static compression. Volume changes in shock-induced transitions must occur very rapidly to produce the structured shock waves observed, so transition rates are large under these dynamic conditions. By contrast, the same transition might require minutes or hours under quasi-static loading. If shock-induced transition is so rapid that kinetic effects can be ignored, a steady two-wave structure is propagated. The first wave, of amplitude equal to the transition pressure, shocks the material to the phase boundary but produces no transition; the second, slower wave produces the transformed phase. When kinetic effects are important, this two-wave structure does not form immediately but by an evolutionary process which produces transients in the amplitudes and rise times of the stress waves. By measuring these transient effects, some facts about the kinetics of phase transitions have been inferred. Comprehensive studies on phase-transition kinetics in antimony, iron, and potassium chloride are described, with emphasis on a thermodynamic description of the intermediate states during transition. Complicating effects such as shear strength and wave perturbations due to free surfaces are discussed.

  8. Pressure induced phase transitions in ceramic compounds containing tetragonal zirconia

    Energy Technology Data Exchange (ETDEWEB)

    Sparks, R.G.; Pfeiffer, G.; Paesler, M.A.

    1988-12-01

    Stabilized tetragonal zirconia compounds exhibit a transformation toughening process in which stress applied to the material induces a crystallographic phase transition. The phase transition is accompanied by a volume expansion in the stressed region thereby dissipating stress and increasing the fracture strength of the material. The hydrostatic component of the stress required to induce the phase transition can be investigated by the use of a high pressure technique in combination with Micro-Raman spectroscopy. The intensity of Raman lines characteristic for the crystallographic phases can be used to calculate the amount of material that has undergone the transition as a function of pressure. It was found that pressures on the order of 2-5 kBar were sufficient to produce an almost complete transition from the original tetragonal to the less dense monoclinic phase; while a further increase in pressure caused a gradual reversal of the transition back to the original tetragonal structure.

  9. Analysis of the competition between forbidden and hyperfine-induced transitions in Ne-like ions

    Science.gov (United States)

    Andersson, Martin; Grumer, Jon; Brage, Tomas; Zou, Yaming; Hutton, Roger

    2016-03-01

    In this work we investigate the decay of the |2 p53 s P30> state in neon-like ions along the isoelectronic sequence ranging from Z =10 to Z =35 . In the absence of a nuclear spin, the magnetic dipole transition to |2 p53 s P31> is the dominating decay channel. However, for isotopes with a nuclear spin, the interaction between the nuclear magnetic dipole moment and the electronic field introduces a mixing of |2 p53 s P31> and |P11> into the |P30> state, which in turn opens up a competing hyperfine-induced electric dipole decay channel to the ground state. This hyperfine-induced transition channel clearly dominates over the magnetic dipole channel for the neutral end of the isoelectronic sequence, when present. We give values for the rates of both these competing channels and discuss how the introduction of the hyperfine-induced transition channel could have a dramatic influence on the spectrum, not only because it introduces a new line, but also since it can substantially decrease the intensity of the magnetic dipole 2 p53 s P30→2 p53 s P31 line and affect the predicted ionization balance in different plasmas.

  10. Phase transition in the SRG flow of nuclear interactions

    CERN Document Server

    Timoteo, Varese S; Szpigel, S

    2016-01-01

    We use a chiral interaction at N3LO in the 1S0 channel of the nucleon- nucleon interaction in order to investigate the on-shell transition along the similarity renormalization group flow towards the infrared limit. We find a crossover at a scale that depends on the number of grid points used to discretise the momentum space.

  11. MAGNETIC FIELD INDUCED FIRST-ORDER TRANSITIONS IN DYSPROSIUM ORTHOFERRITE

    OpenAIRE

    Eremenko, V.; Gnatchenko, S.; Kharchenko, N.; Lebedev, P.; Piotrowski, K; Szymczak, H.; Szymczak, R.

    1988-01-01

    New type of magnetic first-order phase transition induced by external magnetic field applied in the ab-plane in DyFeO3 is investigated using different magnetooptic techniques. The phenomenological model of this transition is proposed. The phase diagram in H-T plane has been obtained for various H orientation in the ab-plane.

  12. Phase Transition Induced Fission in Lipid Vesicles

    CERN Document Server

    Leirer, C; Myles, V M; Schneider, M F

    2010-01-01

    In this work we demonstrate how the first order phase transition in giant unilamellar vesicles (GUVs) can function as a trigger for membrane fission. When driven through their gel-fluid phase transition GUVs exhibit budding or pearl formation. These buds remain connected to the mother vesicle presumably by a small neck. Cooling these vesicles from the fluid phase (T>Tm) through the phase transition into the gel state (T

  13. Electric monopole transitions: What they can tell us about nuclear structure

    Energy Technology Data Exchange (ETDEWEB)

    Zganjar, E.F. [Louisiana State Univ., Baton Rouge, LA (United States). Dept. of Physics and Astronomy; Wood, J.L. [Georgia Inst. of Tech., Atlanta, GA (United States). School of Physics

    1997-07-02

    A brief survey of E0 strength in a number of nuclei in different regions of the nuclear chart is presented. The connection between E0 strength and shape coexistence is reviewed. Nuclear structure information obtained from measurements of electric monopole transitions in {sup 184}Pt and {sup 187}Au is discussed. Plans for future experiments utilizing radioactive ion beams and E0 internal pair formation is presented.

  14. Electric monopole transitions: What they can tell us about nuclear structure

    Energy Technology Data Exchange (ETDEWEB)

    Zganjar, E.F. [Louisiana State Univ., Baton Rouge, LA (United States). Dept. of Physics and Astronomy; Wood, J.L. [Georgia Inst. of Tech., Atlanta, GA (United States). School of Physics

    1995-12-31

    A brief survey of E0 strength in a number of nuclei in different regions of the nuclear chart is presented. The connection between E0 strength and shape coexistence is reviewed. Nuclear structure information obtained from measurements of electric monopole transitions in {sup 184}Pt and {sup 187}Au is discussed. Plans for future experiments utilizing radioactive ion beams and E0 internal-pair-formation is presented.

  15. Phase Transition Induced by Small Molecules in Confined Copolymer Films

    Institute of Scientific and Technical Information of China (English)

    ZHOU Ling

    2007-01-01

    We investigate the phase transition induced by small molecules in confined copolymer films by using density functional theory.It is found that the addition of small molecules can effectively promote the phase separation of copolymers.In a symmetric diblock copolymer film,the affinity and concentration of small molecules play an important role in the structure transjtions.The disordered-lamellar transitions lamellar-lamellar transitions and the re-entrant transitions of the same structures are observed.Our results have potential applications in the fabrication of new functional materials.

  16. Pressure-induced structural transition of nonionic micelles

    Indian Academy of Sciences (India)

    V K Aswal; R Vavrin; J Kohlbrecher; A G Wagh

    2008-11-01

    We report dynamic light scattering and small angle neutron scattering studies of the pressure-induced structural transition of nonionic micelles of surfactant polyoxyethylene 10 lauryl ether (C12E10) in the pressure range 0 to 2000 bar. Measurements have been performed on 1 wt% C12E10 in aqueous solution with and without the addition of KF. Micelles undergo sphere to lamellar structural transitions as the pressure is increased. On addition of KF, rod-like micelles exist at ambient pressure, which results in rod-like to lamellar structural transition at a much lower pressure in the presence of KF. Micellar structural transitions have been observed to be reversible.

  17. Behavioral transitions induced by speed and noise in animal aggregates

    Science.gov (United States)

    Cambui, Dorílson S.; Iliass, Tarras

    2017-04-01

    In this paper, we used a self-propelled particle model to study the transition between phases of collective behavior observed in animal aggregates. In these systems, transitions occur when individuals shift from one collective state to another. We investigated transitions induced by both the speed and the noise. Statistical quantities that characterize the phase transition driven by noise, such as order parameter, the Binder cumulant and the susceptibility were analyzed, and we used the finite-size scaling theory to estimate the critical exponent ratios β/ν and γ/ν.

  18. Neutrino Oscillation Induced by Chiral Phase Transition

    Institute of Scientific and Technical Information of China (English)

    MU Cheng-Fu; SUN Gao-Feng; ZHUANG Peng-Fei

    2009-01-01

    Electric charge neutrality provides a relationship between chiral dynamics and neutrino propagation in compact stars.Due to the sudden drop of the electron density at the first-order chiral phase transition,the oscillation for low energy neutrinos is significant and can be regarded as a signature of chiral symmetry restoration in the core of compact stars.

  19. Transition-Selective Pulses in Zero-Field Nuclear Magnetic Resonance.

    Science.gov (United States)

    Sjolander, Tobias F; Tayler, Michael C D; King, Jonathan P; Budker, Dmitry; Pines, Alexander

    2016-06-30

    We use low-amplitude, ultralow frequency pulses to drive nuclear spin transitions in zero and ultralow magnetic fields. In analogy to high-field NMR, a range of sophisticated experiments becomes available as these allow narrow-band excitation. As a first demonstration, pulses with excitation bandwidths 0.5-5 Hz are used for population redistribution, selective excitation, and coherence filtration. These methods are helpful when interpreting zero- and ultralow-field NMR spectra that contain a large number of transitions.

  20. INDUCED NUCLEAR ACTIVITY IN GALAXY PAIRS

    Directory of Open Access Journals (Sweden)

    F. J. Hernández-Ibarra

    2011-01-01

    Full Text Available Analizamos espectros del núcleo de 893 galaxias entre pares de galaxias y galaxias aisladas de la muestra SLOAN (DR7. Estos pares pueden ser divididos en tres grupos: S+S, E+E y E+S de acuerdo con el catálago de pares aislados de galaxias de Karachentsev (KPG. También analizamos dos muestras de galaxias aisladas: el catálogo de galaxias aisladas de Karachentseva (CIG y la muestra de galaxias aisladas en el hemisferio norte de Varela. Estudiamos la incidencia de la actividad nuclear en cada grupo. Nuestros resultados muestran que la incidencia de actividad nuclear es significativamente mayor en galaxias pares que en las aisladas. Más aún, mostramos que esta incidencia es mayor para galaxias con morfología de tipo temprano. La presencia del bulbo parece ser crucial para explicar cómo se alimenta el hoyo negro supermasivo en AGN. También confirmamos que los AGN de tipo 1 están casi ausentes en toda la muestra. Este resultado no es posible explicarlo tomando sólo en cuenta un modelo unificado.

  1. Pressure-induced phase transition in CrO2.

    Science.gov (United States)

    Alptekin, Sebahaddin

    2015-12-01

    The ab initio constant pressure molecular dynamics technique and density functional theory with generalized gradient approximation (GGA) was used to study the pressure-induced phase transition of CrO2. The phase transition of the rutile (P42/mnm) to the orthorhombic CaCl2 (Pnnm) structure at 30 GPa was determined successfully in a constant pressure simulation. This phase transition was analyzed from total energy calculations and, from the enthalpy calculation, occurred at around 17 GPa. Structural properties such as bulk modules, lattice parameters and phase transition were compared with experimental results. The phase transition at 12 ± 3 GPa was in good agreement with experimental results, as was the phase transition from the orthorhombic CaCl2 (Pnnm) to the monoclinic (P21/c) structure also found at 35 GPa.

  2. Molecular Dynamics Simulations of a Pressure-induced Glass Transition

    CERN Document Server

    Shumway, S L; Jonsson, H; Shumway, Shelly L.; Clarke, Andrew S.

    1994-01-01

    We simulate the compression of a two-component Lennard-Jones liquid at a variety of constant temperatures using a molecular dynamics algorithm in an isobaric-isothermal ensemble. The viscosity of the liquid increases with pressure, undergoing a broadened transition into a structurally arrested, amorphous state. This transition, like the more familiar one induced by cooling, is correlated with a significant increase in icosahedral ordering. In fact, the structure of the final state, as measured by an analysis of the bonding, is essentially the same in the glassy, frozen state whether produced by squeezing or by cooling under pressure. We have computed an effective hard-sphere packing fraction at the transition, defining the transition pressure or temperature by a cutoff in the diffusion constant, analogous to the traditional laboratory definition of the glass transition by an arbitrary, low cutoff in viscosity. The packing fraction at this transition point is not constant, but is consistently higher for runs c...

  3. Advanced Nuclear Fuel Cycle Transitions: Optimization, Modeling Choices, and Disruptions

    Science.gov (United States)

    Carlsen, Robert W.

    Many nuclear fuel cycle simulators have evolved over time to help understan the nuclear industry/ecosystem at a macroscopic level. Cyclus is one of th first fuel cycle simulators to accommodate larger-scale analysis with it liberal open-source licensing and first-class Linux support. Cyclus also ha features that uniquely enable investigating the effects of modeling choices o fuel cycle simulators and scenarios. This work is divided into thre experiments focusing on optimization, effects of modeling choices, and fue cycle uncertainty. Effective optimization techniques are developed for automatically determinin desirable facility deployment schedules with Cyclus. A novel method fo mapping optimization variables to deployment schedules is developed. Thi allows relationships between reactor types and scenario constraints to b represented implicitly in the variable definitions enabling the usage o optimizers lacking constraint support. It also prevents wasting computationa resources evaluating infeasible deployment schedules. Deployed power capacit over time and deployment of non-reactor facilities are also included a optimization variables There are many fuel cycle simulators built with different combinations o modeling choices. Comparing results between them is often difficult. Cyclus flexibility allows comparing effects of many such modeling choices. Reacto refueling cycle synchronization and inter-facility competition among othe effects are compared in four cases each using combinations of fleet of individually modeled reactors with 1-month or 3-month time steps. There are noticeable differences in results for the different cases. The larges differences occur during periods of constrained reactor fuel availability This and similar work can help improve the quality of fuel cycle analysi generally There is significant uncertainty associated deploying new nuclear technologie such as time-frames for technology availability and the cost of buildin advanced reactors

  4. Transitioning nuclear fuel cycles with uncertain fast reactor costs

    Energy Technology Data Exchange (ETDEWEB)

    Phathanapirom, U.B., E-mail: bphathanapirom@utexas.edu; Schneider, E.A.

    2016-06-15

    This paper applies a novel decision making methodology to a case study involving choices leading to the transition from the current once-through light water reactor fuel cycle to one relying on continuous recycle of plutonium and minor actinides in fast reactors in the face of uncertain fast reactor capital costs. Unique to this work is a multi-stage treatment of a range of plausible trajectories for the evolution of fast reactor capital costs over time, characterized by first-of-a-kind penalties as well as time- and unit-based learning. The methodology explicitly incorporates uncertainties in key parameters into the decision-making process by constructing a stochastic model and embedding uncertainties as bifurcations in the decision tree. “Hedging” strategies are found by applying a choice criterion to select courses of action which mitigate “regrets”. These regrets are calculated by evaluating the performance of all possible transition strategies for every feasible outcome of the uncertain parameter. The hedging strategies are those that preserve the most flexibility for adjusting the fuel cycle strategy in response to new information as uncertainties are resolved.

  5. Beyond Nuclear Pasta: Phase Transitions and Neutrino Opacity of Non-Traditional Pasta

    CERN Document Server

    Alcain, Pablo N; Dorso, Claudio O

    2014-01-01

    In this work, we focus on different length scales within the dynamics of nucleons in conditions according to the neutron star crust, with a semiclassical molecular dynamics model, studying isospin symmetric matter at subsaturation densities. While varying the temperature, we find that a solid-liquid phase transition exists, that can be also characterized with a morphology transition. For higher temperatures, above this phase transition, we study the neutrino opacity, and find that in the liquid phase, the scattering of low momenta neutrinos remain high, even though the morphology of the structures differ significatively from those of the traditional nuclear pasta.

  6. Beyond nuclear "pasta" : Phase transitions and neutrino opacity of new "pasta" phases

    Science.gov (United States)

    Alcain, P. N.; Giménez Molinelli, P. A.; Dorso, C. O.

    2014-12-01

    In this work, we focus on different length scales within the dynamics of nucleons in conditions according to the neutron star crust, with a semiclassical molecular dynamics model, studying isospin symmetric matter at subsaturation densities. While varying the temperature, we find that a solid-liquid phase transition exists, which can be also characterized with a morphology transition. For higher temperatures, above this phase transition, we study the neutrino opacity, and find that in the liquid phase, the scattering of low momenta neutrinos remain high, even though the morphology of the structures differ significatively from those of the traditional nuclear pasta.

  7. Nuclear two-photon decay in 0 +→0 + transitions

    Science.gov (United States)

    Kramp, J.; Habs, D.; Kroth, R.; Music, M.; Schirmer, J.; Schwalm, D.; Broude, C.

    1987-11-01

    The two-photon decay of the first excited 0 + state of 16O has been measured using the Heidelberg-Darmstadt crystal ball. A branching ratio of {Γ γγ}/{Γ tot} = (6.6±0.5) · 10 -4 was obtained. As in the cases of 40Ca and 90Zr previously reported by us, the 2γ decay of 16O proceeds via double E1 and M1 transitions of similar strength; the evidence is the observed interference term in the 2γ angular correlation. The ratio of the matrix elements {α E1 }/{χ} for 16O was restricted to the two inverse values (-6.2±1.5) or (-0.16±0.04). An interpretation of 2γ matrix elements observed for 16O, 40Ca and 90Zr in terms of the electric polarizabilities and magnetic susceptibility is given leading to a qualitative understanding of this decay mode.

  8. Transition Operators Entering Neutrinoles Double Electron Capture to Excited Nuclear States

    CERN Document Server

    Vergados, J D

    2011-01-01

    We construct the effective transition operators relevant for neutrinoless double electron capture leading to final nuclear states different than $0^{+}$. From the structure of these operators we see that, if such a process is observed experimentally, it will be very helpful in singling out the very important light neutrino mass contribution from the other lepton violating mechanisms

  9. On the graphical extraction of multipole mixing ratios of nuclear transitions

    Science.gov (United States)

    Rezynkina, K.; Lopez-Martens, A.; Hauschild, K.

    2017-02-01

    We propose a novel graphical method for determining the mixing ratios δ and their associated uncertainties for mixed nuclear transitions. It incorporates the uncertainties on both the measured and the theoretical conversion coefficients. The accuracy of the method has been studied by deriving the corresponding probability density function. The domains of applicability of the method are carefully defined.

  10. Quantum measurement corrections to chemically induced dynamic nuclear polarization

    CERN Document Server

    Kominis, I K

    2013-01-01

    Chemically induced dynamic nuclear polarization has emerged as a universal signature of spin order in photosynthetic reaction centers. Such polarization, significantly enhanced above thermal equilibrium, is known to result from the nuclear spin sorting inherent in the radical pair mechanism underlying long-lived charge-separated states in photosynthetic reaction centers. We will here show that the recently understood fundamental quantum dynamics of radical-ion-pair reactions open up a new and completely unexpected venue towards obtaining CIDNP signals. The fundamental decoherence mechanism inherent in the recombination process of radical pairs is shown to produce nuclear spin polarizations on the order of $10^4$ times or more higher than thermal equilibrium values at low fields relevant to natural photosynthesis in earth's magnetic field. This opens up the possibility of a fundamentally new exploration of the biological significance of high nuclear polarizations in photosynthesis.

  11. Optically induced dynamic nuclear spin polarisation in diamond

    Science.gov (United States)

    Scheuer, Jochen; Schwartz, Ilai; Chen, Qiong; Schulze-Sünninghausen, David; Carl, Patrick; Höfer, Peter; Retzker, Alexander; Sumiya, Hitoshi; Isoya, Junichi; Luy, Burkhard; Plenio, Martin B.; Naydenov, Boris; Jelezko, Fedor

    2016-01-01

    The sensitivity of magnetic resonance imaging (MRI) depends strongly on nuclear spin polarisation and, motivated by this observation, dynamical nuclear spin polarisation has recently been applied to enhance MRI protocols (Kurhanewicz et al 2011 Neoplasia 13 81). Nuclear spins associated with the 13C carbon isotope (nuclear spin I = 1/2) in diamond possess uniquely long spin lattice relaxation times (Reynhardt and High 2011 Prog. Nucl. Magn. Reson. Spectrosc. 38 37). If they are present in diamond nanocrystals, especially when strongly polarised, they form a promising contrast agent for MRI. Current schemes for achieving nuclear polarisation, however, require cryogenic temperatures. Here we demonstrate an efficient scheme that realises optically induced 13C nuclear spin hyperpolarisation in diamond at room temperature and low ambient magnetic field. Optical pumping of a nitrogen-vacancy centre creates a continuously renewable electron spin polarisation which can be transferred to surrounding 13C nuclear spins. Importantly for future applications we also realise polarisation protocols that are robust against an unknown misalignment between magnetic field and crystal axis.

  12. Particle production in antiproton induced nuclear reactions

    CERN Document Server

    Feng, Zhao-Qing

    2014-01-01

    The quantum molecular dynamics model has been improved to investigate the reaction dynamics induced by antiprotons. The reaction channels of elastic scattering, annihilation, charge exchange and inelastic collisions have been included in the model. Dynamics on particle production, in particular pions, kaons, antikaons and hyperons, is investigated in collisions of $\\overline{p}$ on $^{12}$C, $^{20}$Ne, $^{40}$Ca, $^{112}$Sn, $^{181}$Ta, $^{197}$Au and $^{238}$U from a low to high incident momentum. The rapidity and momentum distributions of $\\pi^{+}$ and protons from the LEAR measurements can be well reproduced. The impacts of system size and incident momentum on particle emissions are investigated from the inclusive spectra, transverse momentum and rapidity distributions. It is found that the annihilations of $\\overline{p}$ on nucleons are of importance on the particle production. Hyperons are mainly produced via meson induced reactions on nucleons and strangeness exchange collisions when the incident moment...

  13. Nuclear receptors : mediators and modifiers of inflammation-induced cholestasis

    NARCIS (Netherlands)

    Mulder, Jaap; Karpen, Saul J.; Tietge, Uwe J. F.; Kuipers, Folkert

    2009-01-01

    Inflammation-induced cholestasis (IIC) is a frequently occurring phenomenon. A central role in its pathogenesis is played by nuclear receptors (NRs). These ligand-activated transcription factors not only regulate basal expression of hepatobiliary transport systems, but also mediate adaptive response

  14. Nuclear-induced XeBr/asterisk/ photolytic laser model

    Science.gov (United States)

    Wilson, J. W.

    1980-01-01

    Parameters for a photolytically pumped alkyl iodide lasant gas by the nuclear-induced XeBr excimer fluorescence are calculated according to a detailed kinetic model. High gain on the atomic iodine 2P1/2 state is estimated and 100-mJ pulses with an average power output on the order of 1 kW appear possible.

  15. Field-induced stacking transition of biofunctionalized trilayer graphene

    Energy Technology Data Exchange (ETDEWEB)

    Masato Nakano, C. [Flintridge Preparatory School, La Canada, California 91011 (United States); Sajib, Md Symon Jahan; Samieegohar, Mohammadreza; Wei, Tao [Dan F. Smith Department of Chemical Engineering, Lamar University, Beaumont, Texas 77710 (United States)

    2016-02-01

    Trilayer graphene (TLG) is attracting a lot of attention as their stacking structures (i.e., rhombohedral vs. Bernal) drastically affect electronic and optical properties. Based on full-atom molecular dynamics simulations, we here predict electric field-induced rhombohedral-to-Bernal transition of TLG tethered with proteins. Furthermore, our simulations show that protein's electrophoretic mobility and diffusivity are enhanced on TLG surface. This phenomenon of controllable TLG stacking transition will contribute to various applications including biosensing.

  16. NUSTART: A PC code for NUclear STructure And Radiative Transition analysis and supplementation

    Energy Technology Data Exchange (ETDEWEB)

    Larsen, G.L.; Gardner, D.G.; Gardner, M.A.

    1990-10-01

    NUSTART is a computer program for the IBM PC/At. It is designed for use with the nuclear reaction cross-section code STAPLUS, which is a STAPRE-based CRAY computer code that is being developed at Lawrence Livermore National Laboratory. The NUSTART code was developed to handle large sets of discrete nuclear levels and the multipole transitions among these levels; it operates in three modes. The Data File Error Analysis mode analyzes an existing STAPLUS input file containing the levels and their multipole transition branches for a number of physics and/or typographical errors. The Interactive Data File Generation mode allows the user to create input files of discrete levels and their branching fractions in the format required by STAPLUS, even though the user enters the information in the (different) format used by many people in the nuclear structure field. In the Branching Fractions Calculations mode, the discrete nuclear level set is read, and the multipole transitions among the levels are computed under one of two possible assumptions: (1) the levels have no collective character, or (2) the levels are all rotational band heads. Only E1, M1, and E2 transitions are considered, and the respective strength functions may be constants or, in the case of E1 transitions, the strength function may be energy dependent. The first option is used for nuclei closed shells; the bandhead option may be used to vary the E1, M1, and E2 strengths for interband transitions. K-quantum number selection rules may be invoked if desired. 19 refs.

  17. Particle number scale invariant feature of the states around the critical point of the first order nuclear shape phase transition

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    We study systematically the evolutive behaviors of some energy ratios,E2 transition rate ratios and isomer shift in the nuclear shape phase transitions.We find that the quantities sensitive to the phase transition and independent of free parameter(s) are approximately particle number N scale invariant around the critical point of the first order phase transition,similar to that in the second order phase transition.

  18. Particle number scale invariant feature of the states around the critical point of the first order nuclear shape phase transition

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yu; HOU ZhanFeng; LIU YuXin

    2009-01-01

    We study systematically the evolutive behaviors of some energy ratios,E2 transition rate ratios and Isomer shift in the nuclear shape phase transitions.We find that the quantities sensitive to the phase transition and independent of free parameter(s) are approximately particle number N scale invariant around the critical point of the first order phase transition,similar to that in the second order phase transition.

  19. Experimental and theoretical investigations on shock wave induced phase transitions

    Science.gov (United States)

    Gupta, Satish C.; Sikka, S. K.

    2001-06-01

    Shock wave loading of a material can cause variety of phase transitions, like polymorphism, amorphization, metallization and molecular dissociations. As the shocked state lasts only for a very short duration (about a few microseconds or less), in-situ microscopic measurements are very difficult. Although such studies are beginning to be possible, most of the shock-induced phase transitions are detected using macroscopic measurements. The microscopic nature of the transition is then inferred from comparison with static pressure data or interpreted by theoretical methods. For irreversible phase transitions, microscopic measurements on recovered samples, together with orientation relations determined from selected area electron diffraction and examination of the morphology of growth of the new phase can provide insight into mechanism of phase transitions. On theoretical side, the current ab initio band structure techniques based on density functional formalism provide capability for accurate computation of the small energy differences (a few mRy or smaller) between different plausible structures. Total energy calculation along the path of a phase transition can furnish estimates of activation barrier, which has implications for understanding kinetics of phase transitions. Molecular dynamics calculations, where the new structure evolves naturally, are becoming increasingly popular especially for understanding crystal to amorphous phase transitions. Illustrations from work at our laboratory will be presented.

  20. Shape transitions during clathrin-induced endocytosis

    Science.gov (United States)

    Kumar, Gaurav; Sain, Anirban

    2016-12-01

    Endocytosis is among the most common transport mechanisms which cells employ to receive macromolecules, the so-called cargo, from its extra cellular environment. Clathrin-mediated endocytosis (CME), in particular, involves the cytoplasmic protein clathrin which induces formation and internalization of clathrin-coated membrane buds that contain extra-cellular cargo. Decades of experimental work have established that the morphology of the clathrin coat evolves with time and induces its curvature on the membrane bud; but energetics of the process remain unclear. Recent experiments by Avinoam et al. [Science 348, 1369 (2015), 10.1126/science.aaa9555] reported that the area of the clathrin coat remains fixed while its curvature increases with time and also the clathrin molecules in the coat turn over rapidly. We show that these observations challenge existing models of coated membrane bud formation. We analyze their data to bring out certain features consistent with the underlying lattice structure of the coat. We hypothesize that membrane curvature inhibits clathrin deposition and propose a kinetic model that explains the area distribution of clathrin coats. We also show that their data on shape evolution of the coated membrane bud can be approximately understood from simple geometric considerations. However, the energetics of the coat formation which controls the kinetics of the process remains a puzzle.

  1. BCS-BEC crossover and liquid-gas phase transition in nuclear matter

    Energy Technology Data Exchange (ETDEWEB)

    Jin Meng [Institute of Particle Physics and Physical Department, Central China Normal University, Wuhan 4300079 (China); Urban, Michael [Groupe de Physique Theorique, Institut de Physique Nucleaire -Centre Scientifique d' Orsay, F-91406 Orsay (France); Schuck, Peter, E-mail: jinm@iopp.ccnu.edu.cn [Laboratoire de Physique et Modelisation des Milieux Condenses,CNRS and Universite Joseph Fourier, BP 166, 38042 Grenoble Cedex (France)

    2011-09-16

    The effect of nucleon-nucleon correlations in symmetric nuclear matter at finite temperature is studied beyond BCS theory. We calculate the critical temperature for a BEC superfluid of deuterons, of a BCS superfluid of nucleons, and in the crossover between these limits. The effect of the correlations on the liquid-gas phase transition is discussed. Our results show that nucleon-nucleon correlations beyond BCS play an important role for the properties of nuclear matter, especially in the low-density region.

  2. Atomic clock with a nuclear transition: solid state approach at TU Wien

    CERN Document Server

    Kazakov, G A; Winkler, G; Sterba, J H; Steinhauser, G; Schumm, T

    2011-01-01

    The nucleus of 229Thorium presents a unique isomer state of very low energy and long lifetime, current estimates are around 7.8 eV and seconds to hours respectively. This nuclear transitions therefore is a promising candidate for a novel type of frequency standard and several groups worldwide have set out to investigate this system. Our aim is to construct a "solid state nuclear clock", i.e. a frequency standard where Thorium ions are implanted into Calciumfluoride crystals transparent in vacuum ultraviolet range. As a first step towards an accurate determination of the exact energy and lifetime of this isomer state we perform low-resolution fluorescent spectroscopic measurements.

  3. A primer for electroweak induced low-energy nuclear reactions

    Indian Academy of Sciences (India)

    Y N Srivastava; A Widom; L Larsen

    2010-10-01

    Under special circumstances, electromagnetic and weak interactions can induce low-energy nuclear reactions to occur with observable rates for a variety of processes. A common element in all these applications is that the electromagnetic energy stored in many relatively slow-moving electrons can – under appropriate circumstances – be collectively transferred into fewer, much faster electrons with energies sufficient for the latter to combine with protons (or deuterons, if present) to produce neutrons via weak interactions. The produced neutrons can then initiate low-energy nuclear reactions through further nuclear transmutations. The aim of this paper is to extend and enlarge upon various examples analysed previously, present order of magnitude estimates for each and to illuminate a common unifying theme amongst all of them.

  4. Real-time electron dynamics simulation of two-electron transfer reactions induced by nuclear motion

    Science.gov (United States)

    Suzuki, Yasumitsu; Yamashita, Koichi

    2012-04-01

    Real-time electron dynamics of two-electron transfer reactions induced by nuclear motion is calculated by three methods: the numerically exact propagation method, the time-dependent Hartree (TDH) method and the Ehrenfest method. We find that, as long as the nuclei move as localized wave packets, the TDH and Ehrenfest methods can reproduce the exact electron dynamics of a simple charge transfer reaction model containing two electrons qualitatively well, even when nonadiabatic transitions between adiabatic states occur. In particular, both methods can reproduce the cases where a complete two-electron transfer reaction occurs and those where it does not occur.

  5. Changing nuclear landscape and unique PML structures during early epigenetic transitions of human embryonic stem cells.

    Science.gov (United States)

    Butler, John T; Hall, Lisa L; Smith, Kelly P; Lawrence, Jeanne B

    2009-07-01

    The complex nuclear structure of somatic cells is important to epigenomic regulation, yet little is known about nuclear organization of human embryonic stem cells (hESC). Here we surveyed several nuclear structures in pluripotent and transitioning hESC. Observations of centromeres, telomeres, SC35 speckles, Cajal Bodies, lamin A/C and emerin, nuclear shape and size demonstrate a very different "nuclear landscape" in hESC. This landscape is remodeled during a brief transitional window, concomitant with or just prior to differentiation onset. Notably, hESC initially contain abundant signal for spliceosome assembly factor, SC35, but lack discrete SC35 domains; these form as cells begin to specialize, likely reflecting cell-type specific genomic organization. Concomitantly, nuclear size increases and shape changes as lamin A/C and emerin incorporate into the lamina. During this brief window, hESC exhibit dramatically different PML-defined structures, which in somatic cells are linked to gene regulation and cancer. Unlike the numerous, spherical somatic PML bodies, hES cells often display approximately 1-3 large PML structures of two morphological types: long linear "rods" or elaborate "rosettes", which lack substantial SUMO-1, Daxx, and Sp100. These occur primarily between Day 0-2 of differentiation and become rare thereafter. PML rods may be "taut" between other structures, such as centromeres, but clearly show some relationship with the lamina, where PML often abuts or fills a "gap" in early lamin A/C staining. Findings demonstrate that pluripotent hES cells have a markedly different overall nuclear architecture, remodeling of which is linked to early epigenomic programming and involves formation of unique PML-defined structures.

  6. Ultrafast Hot Electron Induced Phase Transitions in Vanadium Dioxide

    Directory of Open Access Journals (Sweden)

    Haglund R. F.

    2013-03-01

    Full Text Available The Au/Cr/VO2/Si system was investigated in pump–probe experiments. Hot-electrons generated in the Au were found to penetrate into the underlying VO2 and couple with its lattice inducing a semiconductor-to-metal phase transition in ~2 picoseconds.

  7. Effects of Induced Surface Tension in Nuclear and Hadron Matter

    CERN Document Server

    Sagun, V V; Ivanytskyi, A I; Oliinychenko, D R; Mishustin, I N

    2016-01-01

    Short range particle repulsion is rather important property of the hadronic and nuclear matter equations of state. We present a novel equation of state which is based on the virial expansion for the multicomponent mixtures with hard-core repulsion. In addition to the hard-core repulsion taken into account by the proper volumes of particles, this equation of state explicitly contains the surface tension which is induced by another part of the hard-core repulsion between particles. At high densities the induced surface tension vanishes and the excluded volume treatment of hard-core repulsion is switched to its proper volume treatment. Possible applications of this equation of state to a description of hadronic multiplicities measured in A+A collisions, to an investigation of the nuclear matter phase diagram properties and to the neutron star interior modeling are discussed.

  8. Effects of Induced Surface Tension in Nuclear and Hadron Matter

    Directory of Open Access Journals (Sweden)

    Sagun V.V.

    2017-01-01

    Full Text Available Short range particle repulsion is rather important property of the hadronic and nuclear matter equations of state. We present a novel equation of state which is based on the virial expansion for the multicomponent mixtures with hard-core repulsion. In addition to the hard-core repulsion taken into account by the proper volumes of particles, this equation of state explicitly contains the surface tension which is induced by another part of the hard-core repulsion between particles. At high densities the induced surface tension vanishes and the excluded volume treatment of hard-core repulsion is switched to its proper volume treatment. Possible applications of this equation of state to a description of hadronic multiplicities measured in A+A collisions, to an investigation of the nuclear matter phase diagram properties and to the neutron star interior modeling are discussed.

  9. Polarized nuclear target based on parahydrogen induced polarization

    Energy Technology Data Exchange (ETDEWEB)

    Budker, D., E-mail: dbudker@gmail.com [Department of Physics, University of California at Berkeley, Berkeley, CA 94720-7300 (United States); Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Ledbetter, M.P. [Department of Physics, University of California at Berkeley, Berkeley, CA 94720-7300 (United States); Appelt, S. [Central Institute for Electronics, Research Center Juelich, D-52425 Juelich (Germany); Bouchard, L.S. [Department of Chemistry and Biochemistry, California NanoSystems Institute, Biomedical Engineering IDP, Jonsson Comprehensive Cancer Center, University of California, Los Angeles, CA 90095 (United States); Wojtsekhowski, B. [Thomas Jefferson National Accelerator Facility, Newport News, VA 23606 (United States)

    2012-12-01

    We discuss a novel concept of a polarized nuclear target for accelerator fixed-target scattering experiments, which is based on parahydrogen induced polarization (PHIP). One may be able to reach a 33% free-proton polarization in the ethane molecule. The potential advantages of such a target include operation at zero magnetic field, fast ({approx}100Hz) polarization oscillation (akin to polarization reversal), and operation with large intensity of an electron beam. -- Highlights: Black-Right-Pointing-Pointer Novel concept for polarized nuclear targets. Black-Right-Pointing-Pointer The target features fast reversal and operates at near-zero magnetic field. Black-Right-Pointing-Pointer Based on the technique of parahydrogen induced polarization that is revolutionizing NMR and enables NMR/MRI without magnets. Black-Right-Pointing-Pointer Competitive figure-of-merit for polarized targets.

  10. Polarized nuclear target based on parahydrogen induced polarization

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-12-01

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

  11. Nuclear reactions induced by high-energy alpha particles

    Science.gov (United States)

    Shen, B. S. P.

    1974-01-01

    Experimental and theoretical studies of nuclear reactions induced by high energy protons and heavier ions are included. Fundamental data needed in the shielding, dosimetry, and radiobiology of high energy particles produced by accelerators were generated, along with data on cosmic ray interaction with matter. The mechanism of high energy nucleon-nucleus reactions is also examined, especially for light target nuclei of mass number comparable to that of biological tissue.

  12. Thermal Transition of Ribonuclease A Observed Using Proton Nuclear Magnetic Resonance

    Institute of Scientific and Technical Information of China (English)

    闫永彬; 罗雪春; 周海梦; 张日清

    2001-01-01

    The thermal transition of bovine pancreatic ribonuclease A (RNase A) was investigated using proton nuclear magnetic resonance (NMR). Significant resonance overlap in the large native protein limits accurate assignments in the 1H NMR spectrum. This study proposes extending the investigation of large proteins by dynamic analysis. Comparison of the traditional method and the correlation coefficient method suggests successful application of spectrum image analysis in dynamic protein studies by NMR.

  13. Results of a direct search using synchrotron radiation for the low-energy $^{229}$Th nuclear isomeric transition

    CERN Document Server

    Jeet, Justin; Sullivan, Scott T; Rellergert, Wade G; Mirzadeh, Saed; Cassanho, A; Jenssen, H P; Tkalya, Eugene V; Hudson, Eric R

    2015-01-01

    We report the results of a direct search for the $^{229}$Th ($I^{p} = 3/2^+\\leftarrow 5/2^+$) nuclear isomeric transition, performed by exposing $^{229}$Th-doped LiSrAlF$_6$ crystals to tunable vacuum-ultraviolet synchrotron radiation and observing any resulting fluorescence. We also use existing nuclear physics data to establish a range of possible transition strengths for the isomeric transition. We find no evidence for the thorium nuclear transition between $7.3 \\mbox{eV}$ and $8.8 \\mbox{eV}$ with transition lifetime $(1-2)\\mbox{s} \\lesssim \\tau \\lesssim (2000-5600)\\mbox{s}$. This measurement excludes roughly half of the favored transition search area and can be used to direct future searches.

  14. Results of a Direct Search Using Synchrotron Radiation for the Low-Energy (229)Th Nuclear Isomeric Transition.

    Science.gov (United States)

    Jeet, Justin; Schneider, Christian; Sullivan, Scott T; Rellergert, Wade G; Mirzadeh, Saed; Cassanho, A; Jenssen, H P; Tkalya, Eugene V; Hudson, Eric R

    2015-06-26

    We report the results of a direct search for the (229)Th (I(π)=3/2(+)←5/2(+)) nuclear isomeric transition, performed by exposing (229)Th-doped LiSrAlF(6) crystals to tunable vacuum-ultraviolet synchrotron radiation and observing any resulting fluorescence. We also use existing nuclear physics data to establish a range of possible transition strengths for the isomeric transition. We find no evidence for the thorium nuclear transition between 7.3 eV and 8.8 eV with transition lifetime (1-2) s≲τ≲(2000-5600)  s. This measurement excludes roughly half of the favored transition search area and can be used to direct future searches.

  15. Noise-induced transition in a quantum system

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, Pulak Kumar [Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032 (India); Barik, Debashis [Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032 (India); Ray, Deb Shankar [Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032 (India)]. E-mail: pcdsr@mahendra.iacs.res.in

    2005-07-04

    We examine the noise-induced transition in a fluctuating bistable potential of a driven quantum system in thermal equilibrium. Making use of a Wigner canonical thermal distribution for description of the statistical properties of the thermal bath, we explore the generic effects of quantization like vacuum field fluctuation and tunneling in the characteristic stationary probability distribution functions undergoing transition from unimodal to bimodal nature and in signal-to-noise ratio characterizing the cooperative effect among the noise processes and the weak periodic signal.

  16. Optically induced structural phase transitions in ion Coulomb crystals

    DEFF Research Database (Denmark)

    Horak, Peter; Dantan, Aurelien Romain; Drewsen, Michael

    2012-01-01

    , such as body-centered cubic and face-centered cubic, can be suppressed by a proper choice of the potential depth and periodicity. Furthermore, by varying the harmonic trap parameters and/or the optical potential in time, controlled transitions between crystal structures can be obtained with close to unit......We investigate numerically the structural dynamics of ion Coulomb crystals confined in a three-dimensional harmonic trap when influenced by an additional one-dimensional optically induced periodical potential. We demonstrate that transitions between thermally excited crystal structures...

  17. Pressure induced structural phase transition in IB transition metal nitrides compounds

    Energy Technology Data Exchange (ETDEWEB)

    Soni, Shubhangi; Kaurav, Netram, E-mail: netramkaurav@yahoo.co.uk; Jain, A. [Department of Physics, Govt. Holkar Science college, A. B. Road, Indore-452001 India (India); Shah, S. [Department of Physics, P. M. B. Gujarati Science College, Indore-452001 (India); Choudhary, K. K. [Department of Physics, National Defence Academy, Khadakwasla, Pune-411 0231 India (India)

    2015-06-24

    Transition metal mononitrides are known as refractory compounds, and they have, relatively, high hardness, brittleness, melting point, and superconducting transition temperature, and they also have interesting optical, electronic, catalytic, and magnetic properties. Evolution of structural properties would be an important step towards realizing the potential technological scenario of this material of class. In the present study, an effective interionic interaction potential (EIOP) is developed to investigate the pressure induced phase transitions in IB transition metal nitrides TMN [TM = Cu, Ag, and Au] compounds. The long range Coulomb, van der Waals (vdW) interaction and the short-range repulsive interaction upto second-neighbor ions within the Hafemeister and Flygare approach with modified ionic charge are properly incorporated in the EIOP. The vdW coefficients are computed following the Slater-Kirkwood variational method, as both the ions are polarizable. The estimated value of the phase transition pressure (Pt) and the magnitude of the discontinuity in volume at the transition pressure are consistent as compared to the reported data.

  18. Giant modification of atomic transitions probabilities induced by magnetic field: forbidden transitions become predominant

    CERN Document Server

    Sargsyan, A; Hakhumyan, G; Papoyan, A; Mariotti, E; Sarkisyan, D

    2014-01-01

    Magnetic field-induced giant modification of probabilities for seven components of 6S1/2 (Fg=3) - 6P3/2 (Fe=5) transition of Cs D2 line forbidden by selection rules is observed experimentally for the first time. For the case of excitation with circularly-polarized laser radiation, the probability of Fg=3,mF=-3 - Fe=5,mF=-2 transition becomes the largest among 25 transitions of Fg=3 - Fe=2,3,4,5 group in a wide range of magnetic field 200 - 3200 G. Moreover, the modification is the largest among D2 lines of alkali metals. A half-wave-thick cell (length along the beam propagation axis L=426 nm) filled with Cs has been used in order to achieve sub-Doppler resolution which allows for separating the large number of atomic transitions that appear in the absorption spectrum when an external magnetic field is applied. For B > 3 kG the group of seven transitions Fg=3 - Fe=5 is completely resolved and is located at the high frequency wing of Fg=3 - Fe=2,3,4 transitions. The applied theoretical model very well describes...

  19. Employing Forbidden Transitions as Qubits in a Nuclear Spin-Free Chromium Complex.

    Science.gov (United States)

    Fataftah, Majed S; Zadrozny, Joseph M; Coste, Scott C; Graham, Michael J; Rogers, Dylan M; Freedman, Danna E

    2016-02-01

    The implementation of quantum computation (QC) would revolutionize scientific fields ranging from encryption to quantum simulation. One intuitive candidate for the smallest unit of a quantum computer, a qubit, is electronic spin. A prominent proposal for QC relies on high-spin magnetic molecules, where multiple transitions between the many MS levels are employed as qubits. Yet, over a decade after the original notion, the exploitation of multiple transitions within a single manifold for QC remains unrealized in these high-spin species due to the challenge of accessing forbidden transitions. To create a proof-of-concept system, we synthesized the novel nuclear spin-free complex [Cr(C3S5)3](3-) with precisely tuned zero-field splitting parameters that create two spectroscopically addressable transitions, with one being a forbidden transition. Pulsed electron paramagnetic resonance (EPR) measurements enabled the investigation of the coherent lifetimes (T2) and quantum control (Rabi oscillations) for two transitions, one allowed and one forbidden, within the S = (3)/2 spin manifold. This investigation represents a step forward in the development of high-spin species as a pathway to scalable QC systems within magnetic molecules.

  20. Snail nuclear transport: the gateways regulating epithelial-to-mesenchymal transition?

    Science.gov (United States)

    Muqbil, Irfana; Wu, Jack; Aboukameel, Amro; Mohammad, Ramzi M; Azmi, Asfar S

    2014-08-01

    Epithelial-to-mesenchymal transition (EMT) and the reverse process (MET) play central role in organ developmental biology. It is a fine tuned process that when disturbed leads to pathological conditions especially cancers with aggressive and metastatic behavior. Snail is an oncogene that has been well established to be a promoter of EMT through direct repression of epithelial morphology promoter E-cadherin. It can function in the nucleus, in the cytosol and as discovered recently, extracellularly through secretory vesicular structures. The intracellular transport of snail has for long been shown to be regulated by the nuclear pore complex. One of the Karyopherins, importin alpha, mediates snail import, while exportin 1 (Xpo1) also known as chromosome maintenance region 1 (CRM1) is its major nuclear exporter. A number of additional biological regulators are emerging that directly modulate Snail stability by altering its subcellular localization. These observations indicate that targeting the nuclear transport machinery could be an important and as of yet, unexplored avenue for therapeutic intervention against the EMT processes in cancer. In parallel, a number of novel agents that disrupt nuclear transport have recently been discovered and are being explored for their anti-cancer effects in the early clinical settings. Through this review we provide insights on the mechanisms regulating snail subcellular localization and how this impacts EMT. We discuss strategies on how the nuclear transport function can be harnessed to rein in EMT through modulation of snail signaling. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Parvovirus induced alterations in nuclear architecture and dynamics.

    Directory of Open Access Journals (Sweden)

    Teemu O Ihalainen

    Full Text Available The nucleus of interphase eukaryotic cell is a highly compartmentalized structure containing the three-dimensional network of chromatin and numerous proteinaceous subcompartments. DNA viruses induce profound changes in the intranuclear structures of their host cells. We are applying a combination of confocal imaging including photobleaching microscopy and computational methods to analyze the modifications of nuclear architecture and dynamics in parvovirus infected cells. Upon canine parvovirus infection, expansion of the viral replication compartment is accompanied by chromatin marginalization to the vicinity of the nuclear membrane. Dextran microinjection and fluorescence recovery after photobleaching (FRAP studies revealed the homogeneity of this compartment. Markedly, in spite of increase in viral DNA content of the nucleus, a significant increase in the protein mobility was observed in infected compared to non-infected cells. Moreover, analysis of the dynamics of photoactivable capsid protein demonstrated rapid intranuclear dynamics of viral capsids. Finally, quantitative FRAP and cellular modelling were used to determine the duration of viral genome replication. Altogether, our findings indicate that parvoviruses modify the nuclear structure and dynamics extensively. Intranuclear crowding of viral components leads to enlargement of the interchromosomal domain and to chromatin marginalization via depletion attraction. In conclusion, parvoviruses provide a useful model system for understanding the mechanisms of virus-induced intranuclear modifications.

  2. Pressure-Induced Phase Transitions of n-Tridecane

    Science.gov (United States)

    Yamashita, Motoi

    Pressure-induced phase transition behavior of n-tridecane from the ordered phase through the rotator phase into the liquid phase has been investigated by using Fourier transform infrared spectroscopy at 25 °C. The transition between the ordered and rotator phases has been observed in the pressure range of 270-220 MPa and the transition between the rotator and liquid phases has been observed in the pressure range of 171-112 MPa, within the experimental error of ±50 MPa. The populations of the -gtg- + -gtg'-, -gg- and gt- defects determined from the methylene wagging mode are smaller in the rotator phase than in the liquid phase and are smaller under higher pressure in both of the rotator and liquid phases. A relationship has been found between the conformation and the intensity of the 890 cm-1 band, which has been assigned as the methyl rocking mode and has been considered as insensitive to conformation.

  3. Ghrelin improves burn-induced delayed gastrointestinal transit in rats.

    Science.gov (United States)

    Sallam, H S; Oliveira, H M; Gan, H T; Herndon, D N; Chen, J D Z

    2007-01-01

    Delayed gastrointestinal transit is common in patients with severe burn. Ghrelin is a potent prokinetic peptide. We aimed at testing the effect of ghrelin on burn-induced delayed gastrointestinal transit in rats. Gastric emptying (GE), intestinal transit (IT), and colonic transit (CT) studies were performed in male Sprague-Dawley rats. Rats were randomized into two main groups as follows: sham injury and ghrelin-treated burn injury with doses of 0, 2, 5, and 10 nmol/rat ip 6 h after burn. Sham/burn injury was induced under anesthesia. Rats received a phenol red meal 20 min following ghrelin injection. Based on the most effective ghrelin dose, 1 mg/kg sc atropine was given 30 min before the ghrelin in one group of rats for each study. The rats in each group were killed 30-90 min later; their stomachs, intestines, and colons were harvested immediately, and the amount of phenol red recovered was measured. Percentage of gastric emptying (GE%) and geometric center for IT and CT were calculated. We found 1) severe cutaneous burn injury significantly delayed GE, IT, and CT compared with sham injury (P CT; 3) the most effective dose of ghrelin was 2 nmol/rat; and 4) atropine blocked the prokinetic effects of ghrelin on GE% and IT. In conclusion, ghrelin normalizes burn-induced delayed GE and IT but has no effect on CT in rats. The prokinetic effects of ghrelin are exerted via the cholinergic pathway. Ghrelin may have a therapeutic potential for burn patients with delayed upper gastrointestinal transit.

  4. Noise-induced transition in human reaction times

    Science.gov (United States)

    Medina, José M.; Díaz, José A.

    2016-09-01

    The human reaction/response time can be defined as the time elapsed from the onset of stimulus presentation until a response occurs in many sensory and cognitive processes. A reaction time model based on Piéron’s law is investigated. The model shows a noise-induced transition in the moments of reaction time distributions due to the presence of strong additive noise. The model also demonstrates that reaction times do not follow fluctuation scaling between the mean and the variance but follow a generalized version between the skewness and the kurtosis. The results indicate that noise-induced transitions in the moments govern fluctuations in sensory-motor transformations and open an insight into the macroscopic effects of noise in human perception and action. The conditions that lead to extreme reaction times are discussed based on the transfer of information in neurons.

  5. Neutrino-induced Reactions and Neutrino Scattering with Nuclear Targets

    Science.gov (United States)

    Cheoun, Myung-Ki; Ha, Eunja; Yang, Ghil-Seok; Kim, Kyungsik; Kajino, T.

    2016-02-01

    We reviewed present status regarding experimental data and theoretical approaches for neutrino-induced reactions and neutrino scattering. With a short introduction of relevant data, our recent calculations by distorted-wave Born approximation for quasielastic region are presented for MiniBooNE data. For much higher energy neutrino data, such as NOMAD data, elementary process approach was shown to be useful instead of using complicated nuclear models. But, in the low energy region, detailed nuclear structure model, such as QRPA and shell model, turn out to be inescapable to explain the reaction data. Finally, we discussed that one step-process in the reaction is comparable to the two-step process, which has been usually used in the neutrino-nucleosynthesis.

  6. Neutrino-induced Reactions and Neutrino Scattering with Nuclear Targets

    Directory of Open Access Journals (Sweden)

    Cheoun Myung-Ki

    2016-01-01

    Full Text Available We reviewed present status regarding experimental data and theoretical approaches for neutrino-induced reactions and neutrino scattering. With a short introduction of relevant data, our recent calculations by distorted-wave Born approximation for quasielastic region are presented for MiniBooNE data. For much higher energy neutrino data, such as NOMAD data, elementary process approach was shown to be useful instead of using complicated nuclear models. But, in the low energy region, detailed nuclear structure model, such as QRPA and shell model, turn out to be inescapable to explain the reaction data. Finally, we discussed that one step-process in the reaction is comparable to the two-step process, which has been usually used in the neutrino-nucleosynthesis.

  7. Direct investigations of deformation and yield induced structure transitions in polyamide 6 below glass transition temperature with WAXS and SAXS

    DEFF Research Database (Denmark)

    Guo, Huilong; Wang, Jiayi; Zhou, Chengbo;

    2015-01-01

    Deformation and yield induced structure transitions of polyamide 6 (PA6) were detected with the combination of the wide- and small-angle X-ray scattering (WAXS and SAXS) at 30 degrees C below glass transition temperature (T-g) of PA6. During deformation, gamma-alpha phase transition was found at ...

  8. Quantum phase transition induced by real-space topology

    Science.gov (United States)

    Li, C.; Zhang, G.; Lin, S.; Song, Z.

    2016-12-01

    A quantum phase transition (QPT), including both topological and symmetry breaking types, is usually induced by the change of global parameters, such as external fields or global coupling constants. In this work, we demonstrate the existence of QPT induced by the real-space topology of the system. We investigate the groundstate properties of the tight-binding model on a honeycomb lattice with the torus geometry based on exact results. It is shown that the ground state experiences a second-order QPT, exhibiting the scaling behavior, when the torus switches to a tube, which reveals the connection between quantum phase and the real-space topology of the system.

  9. Quantum phase transition induced by real-space topology.

    Science.gov (United States)

    Li, C; Zhang, G; Lin, S; Song, Z

    2016-12-22

    A quantum phase transition (QPT), including both topological and symmetry breaking types, is usually induced by the change of global parameters, such as external fields or global coupling constants. In this work, we demonstrate the existence of QPT induced by the real-space topology of the system. We investigate the groundstate properties of the tight-binding model on a honeycomb lattice with the torus geometry based on exact results. It is shown that the ground state experiences a second-order QPT, exhibiting the scaling behavior, when the torus switches to a tube, which reveals the connection between quantum phase and the real-space topology of the system.

  10. Towards a direct transition energy measurement of the lowest nuclear excitation in 229Th

    CERN Document Server

    Wense, L v d; Kalb, D; Laatiaoui, M

    2012-01-01

    The isomeric first excited state of the isotope 229Th exhibits the lowest nuclear excitation energy in the whole landscape of known atomic nuclei. For a long time this energy was reported in the literature as 3.5(5) eV, however, a new experiment corrected this energy to 7.6(5) eV, corresponding to a UV transition wavelength of 163(11) nm. The expected isomeric lifetime is $\\tau=$ 3-5 hours, leading to an extremely sharp relative linewidth of Delta E/E ~ 10^-20, 5-6 orders of magnitude smaller than typical atomic relative linewidths. For an adequately chosen electronic state the frequency of the nuclear ground-state transition will be independent from influences of external fields in the framework of the linear Zeeman and quadratic Stark effect, rendering 229mTh a candidate for a reference of an optical clock with very high accuracy. Moreover, in the literature speculations about a potentially enhanced sensitivity of the ground-state transition of $^{229m}$Th for eventual time-dependent variations of fundament...

  11. Induced starburst and nuclear activity: Faith, facts, and theory

    Science.gov (United States)

    Shlosman, Isaac

    1990-01-01

    The problem of the origin of starburst and nuclear (nonstellar) activity in galaxies is reviewed. A physical understanding of the mechanism(s) that induce both types of activity requires one to address the following issues: (1) what is the source of fuel that powers starbursts and active galactic nuclei; and (2) how is it channeled towards the central regions of host galaxies? As a possible clue, the author examines the role of non-axisymmetric perturbations of galactic disks and analyzes their potential triggers. Global gravitational instabilities in the gas on scales approx. 100 pc appear to be crucial for fueling the active galactic nuclei.

  12. The lightning initiation as a noise-induced kinetic transition

    Science.gov (United States)

    Iudin, Dmitry; Rakov, Vladimir

    2017-04-01

    It is common knowledge that observations of thundercloud electric fields have consistently yielded a peak value that is an order of magnitude weaker than the dielectric strength of air. In this work, initiation of lightning in the thundercloud is regarded as a noise-induced kinetic transition. As a source of the noise we consider the collective stochastic electric field of charged hydrometeors. Above-critical bursts of the stochastic field provide the survival of the free electrons in conditions when the RMS level of fluctuations of the field is significantly less than the air electric strength. The considered kinetic transition has several characteristic features that distinguish it from other mechanisms of lightning initiation. First, due to interaction of electron and ion components the dynamic implementation of this transition is stretched in time interval, which significantly exceeds the development time of ordinary spark discharge. In this case the rapid attachment of electrons is balanced by the processes of their liberation during negative ions destruction. Secondly, ions stochastic drift due to the fine-scale electric field fluctuations plays a significant role in the transition kinetics. From a formal mathematical point of view, this stochastic drift is indistinguishable from advection of a scalar impurity in a turbulent flow. It is shown that the effectiveness of "advective mixing" for a few degree surpasses the efficiency of conventional diffusion. Third, noise-induced explosive growth in the density of free electrons and ions is limited to spatial - temporal clusters that have a fractal structure and covering, as a result, a vanishingly small proportion of the actual area of four-dimensional space-time. As a result in the considered transition the average conductivity of the medium does not significantly change. The proposed kinetic mechanism of the initiation of the lightning discharge provides both amplification of the local electric field in a

  13. Critical temperature for the nuclear liquid-gas phase transition (from multifragmentation and fission)

    CERN Document Server

    Karnaukhov, V A; Budzanowski, A; Avdeyev, S P; Botvina, A S; Cherepanov, E A; Karcz, W; Kirakosyan, V V; Rukoyatkin, P A; Skwirczynska, I; Norbeck, E

    2008-01-01

    Critical temperature Tc for the nuclear liquid-gas phase transition is stimated both from the multifragmentation and fission data. In the first case,the critical temperature is obtained by analysis of the IMF yields in p(8.1 GeV)+Au collisions within the statistical model of multifragmentation (SMM). In the second case, the experimental fission probability for excited 188Os is compared with the calculated one with Tc as a free parameter. It is concluded for both cases that the critical temperature is higher than 16 MeV.

  14. Nuclear response functions for the N-N{sup *}(1440) transition

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez-Ruso, L. E-mail: luis.alvarez-ruso@theo.physik.uni-giessen.de; Barbaro, M.B.; Donnelly, T.W.; Molinari, A

    2003-08-25

    Parity-conserving and -violating response functions are computed for the inclusive electroexcitation of the N{sup *}(1440) (Roper) resonance in nuclear matter modeled as a relativistic Fermi gas. Using various empirical parameterizations and theoretical models of the N-N{sup *}(1440) transition form factors, the sensitivity of the response functions to details of the structure of the Roper resonance is investigated. The possibility of disentangling this resonance from the contribution of {delta} electroproduction in nuclei is addressed. Finally, the contributions of the Roper resonance to the longitudinal scaling function and to the Coulomb sum rule are also explored.

  15. On Markov Chains Induced by Partitioned Transition Probability Matrices

    Institute of Scientific and Technical Information of China (English)

    Thomas KAIJSER

    2011-01-01

    Let S be a denumerable state space and let P be a transition probability matrix on S. If a denumerable set M of nonnegative matrices is such that the sum of the matrices is equal to P, then we call M a partition of P. Let K denote the set of probability vectors on S. With every partition M of P we can associate a transition probability function PM on K defined in such a way that if p ∈ K and M ∈ M are such that ‖pM‖ > 0, then, with probability ‖pM‖, the vector p is transferred to the vector pM/‖pM‖. Here ‖· ‖ denotes the l1-norm. In this paper we investigate the convergence in distribution for Markov chains generated by transition probability functions induced by partitions of transition probability matrices. The main motivation for this investigation is the application of the convergence results obtained to filtering processes of partially observed Markov chains with denumerable state space.

  16. Radiation induced corrosion of copper for spent nuclear fuel storage

    Science.gov (United States)

    Björkbacka, Åsa; Hosseinpour, Saman; Johnson, Magnus; Leygraf, Christofer; Jonsson, Mats

    2013-11-01

    The long term safety of repositories for radioactive waste is one of the main concerns for countries utilizing nuclear power. The integrity of engineered and natural barriers in such repositories must be carefully evaluated in order to minimize the release of radionuclides to the biosphere. One of the most developed concepts of long term storage of spent nuclear fuel is the Swedish KBS-3 method. According to this method, the spent fuel will be sealed inside copper canisters surrounded by bentonite clay and placed 500 m down in stable bedrock. Despite the importance of the process of radiation induced corrosion of copper, relatively few studies have been reported. In this work the effect of the total gamma dose on radiation induced corrosion of copper in anoxic pure water has been studied experimentally. Copper samples submerged in water were exposed to a series of total doses using three different dose rates. Unirradiated samples were used as reference samples throughout. The copper surfaces were examined qualitatively using IRAS and XPS and quantitatively using cathodic reduction. The concentration of copper in solution after irradiation was measured using ICP-AES. The influence of aqueous radiation chemistry on the corrosion process was evaluated based on numerical simulations. The experiments show that the dissolution as well as the oxide layer thickness increase upon radiation. Interestingly, the evaluation using numerical simulations indicates that aqueous radiation chemistry is not the only process driving the corrosion of copper in these systems.

  17. Snail Promotes Epithelial Mesenchymal Transition in Breast Cancer Cells in Part via Activation of Nuclear ERK2

    Science.gov (United States)

    Smith, Bethany N.; Burton, Liza J.; Henderson, Veronica; Randle, Diandra D.; Morton, Derrick J.; Smith, Basil A.; Taliaferro-Smith, Latonia; Nagappan, Peri; Yates, Clayton; Zayzafoon, Majd; Chung, Leland W. K.; Odero-Marah, Valerie A.

    2014-01-01

    Snail transcription factor is up-regulated in several cancers and associated with increased tumor migration and invasion via induction of epithelial-to-mesenchymal transition (EMT). MAPK (ERK1/2) signaling regulates cellular processes including cell motility, adhesion, and invasion. We investigated the regulation of ERK1/2 by Snail in breast cancer cells. ERK1/2 activity (p-ERK) was higher in breast cancer patient tissue as compared to normal tissue. Snail and p-ERK were increased in several breast cancer cell lines as compared to normal mammary epithelial cells. Snail knockdown in MDA-MB-231 and T47-D breast cancer cells decreased or re-localized p-ERK from the nuclear compartment to the cytoplasm. Snail overexpression in MCF-7 breast cancer cells induced EMT, increased cell migration, decreased cell adhesion and also increased tumorigenicity. Snail induced nuclear translocation of p-ERK, and the activation of its subcellular downstream effector, Elk-1. Inhibiting MAPK activity with UO126 or knockdown of ERK2 isoform with siRNA in MCF-7 Snail cells reverted EMT induced by Snail as shown by decreased Snail and vimentin expression, decreased cell migration and increased cell adhesion. Overall, our data suggest that ERK2 isoform activation by Snail in aggressive breast cancer cells leads to EMT associated with increased cell migration and decreased cell adhesion. This regulation is enhanced by positive feedback regulation of Snail by ERK2. Therefore, therapeutic targeting of ERK2 isoform may be beneficial for breast cancer. PMID:25122124

  18. Snail promotes epithelial mesenchymal transition in breast cancer cells in part via activation of nuclear ERK2.

    Directory of Open Access Journals (Sweden)

    Bethany N Smith

    Full Text Available Snail transcription factor is up-regulated in several cancers and associated with increased tumor migration and invasion via induction of epithelial-to-mesenchymal transition (EMT. MAPK (ERK1/2 signaling regulates cellular processes including cell motility, adhesion, and invasion. We investigated the regulation of ERK1/2 by Snail in breast cancer cells. ERK1/2 activity (p-ERK was higher in breast cancer patient tissue as compared to normal tissue. Snail and p-ERK were increased in several breast cancer cell lines as compared to normal mammary epithelial cells. Snail knockdown in MDA-MB-231 and T47-D breast cancer cells decreased or re-localized p-ERK from the nuclear compartment to the cytoplasm. Snail overexpression in MCF-7 breast cancer cells induced EMT, increased cell migration, decreased cell adhesion and also increased tumorigenicity. Snail induced nuclear translocation of p-ERK, and the activation of its subcellular downstream effector, Elk-1. Inhibiting MAPK activity with UO126 or knockdown of ERK2 isoform with siRNA in MCF-7 Snail cells reverted EMT induced by Snail as shown by decreased Snail and vimentin expression, decreased cell migration and increased cell adhesion. Overall, our data suggest that ERK2 isoform activation by Snail in aggressive breast cancer cells leads to EMT associated with increased cell migration and decreased cell adhesion. This regulation is enhanced by positive feedback regulation of Snail by ERK2. Therefore, therapeutic targeting of ERK2 isoform may be beneficial for breast cancer.

  19. Equation of State and Phase Transitions in the Nuclear and Hadronic Systems

    CERN Document Server

    Bugaev, Kyrill A

    2010-01-01

    An investigation of strongly interacting matter equation of state remains one of the major tasks of modern high energy nuclear physics for almost a quarter of century. The present work is my doctor of science thesis which contains my contribution (42 works) to this field made between 1993 and 2008. Inhere I mainly discuss the common physical and mathematical features of several exactly solvable statistical models which describe the nuclear liquid-gas phase transition and the deconfinement phase transition. Luckily, in some cases it was possible to rigorously extend the solutions found in thermodynamic limit to finite volumes and to formulate the finite volume analogs of phases directly from the grand canonical partition. It turns out that finite volume (surface) of a system generates also the temporal constraints, i.e. the finite formation/decay time of possible states in this finite system. Among other results I would like to mention the calculation of upper and lower bounds for the surface entropy of physic...

  20. Gap analysis survey: an aid in transitioning to standardized curricula for nuclear medicine technology.

    Science.gov (United States)

    Bires, Angela Macci; Mason, Donna L; Gilmore, David; Pietrzyk, Carly

    2012-09-01

    This article discusses the process by which the Society of Nuclear Medicine Technology Section (SNMTS) is assisting educators as they transition to comply with the fourth edition of the Curriculum Guide for Educational Programs in Nuclear Medicine Technology. An electronic survey was sent to a list of nuclear medicine technology programs compiled by the educational division of the SNMTS. The collected data included committee member demographics, goals and objectives, conference call minutes, consultation discussions, transition examples, 4- and 2-y program curricula, and certificate program curricula. There were 56 responses to the survey. All respondents were program directors, with 3 respondents having more than one type of program, for a total of 59 programs. Of these, 19 (33.93%) were baccalaureate, 19 (28.57%) associate, and 21 (37.5%) certificate. Forty-eight respondents (85.71%) had accreditation through the Joint Review Commission on Educational Programs in Nuclear Medicine Technology, 6 (10.71%) had regional accreditation, and 2 (3.57%) were accredited through other entities. Thirteen categories of required general education courses were identified, and the existing program curricula of 9 (69.2%) courses were more than 50% compliant with the fourth edition Curriculum Guide. The fact that no measurable gap could be found within the didactic professional content across programs was due to the lack of a degree requirement and content standardization within the profession. The data indicated that the participating programs offer a minimum of 1-15 contact hours in emerging technology modalities. The required clinical hours ranged from 765 to 1,920 for degree or certificate completion. The average number of clinical hours required for all programs was 1,331.69. Standardization of the number and types of courses is needed both for current baccalaureate programs and for clinical education. This standardization will guide programs in transitioning from a

  1. Pressure-induced phase transition in GaN nanocrystals

    CERN Document Server

    Cui, Q; Zhang, W; Wang, X; Zhang, J; Cui, T; Xie, Y; Liu, J; Zou, G

    2002-01-01

    High-pressure in situ energy-dispersive x-ray diffraction experiments on GaN nanocrystals with 50 nm diameter have been carried out using a synchrotron x-ray source and a diamond-anvil cell up to about 79 GPa at room temperature. A pressure-induced first-order structural phase transition from the wurtzite-type structure to the rock-salt-type structure starts at about 48.8 GPa. The rock-salt-type phase persists to the highest pressure in our experimental range.

  2. Structural and isospin effects on balance energy and transition energy via different nuclear charge radii parameterizations

    Science.gov (United States)

    Sangeeta; Kaur, Varinderjit

    2017-10-01

    The structural and isospin effects have been studied through isospin dependent and independent nuclear charge radii parameterizations on the collective flow within the framework of Isospin-dependent Quantum Molecular Dynamics (IQMD) model. The calculations have been carried out by using two approaches: (i) for the reaction series having fixed N / Z ratio and (ii) for the isobaric reaction series with different N / Z ratio. Our results indicate that there is a considerable effect of radii parameterizations on the excitation function of reduced flow (∂v1/∂Yred) and elliptical flow (v2). Both balance energy (Ebal) and transition energy (Etrans) are enhanced with increase in radii of reacting nuclei and found to follow a power law with nuclear charge radii. The exponent τ values show that the elliptical flow is more sensitive towards different nuclear charge radii as compared to reduced flow. Moreover, we observe that our theoretical calculation of Ebal and Etrans are in agreement with the experimental data provided by GSI, INDRA and FOPI collaborations.

  3. Transition from Cyclosporine-Induced Renal Dysfunction to Nephrotoxicity in an in Vivo Rat Model

    Directory of Open Access Journals (Sweden)

    José Sereno

    2014-05-01

    Full Text Available Cyclosporin A (CsA, a calcineurin inhibitor, remain the cornerstone of immunosuppressive regimens, regardless of nephrotoxicity, which depends on the duration of drug exposure. The mechanisms and biomarkers underlying the transition from CsA-induced renal dysfunction to nephrotoxicity deserve better elucidation, and would help clinical decisions. This study aimed to clarify these issues, using a rat model of short- and long-term CsA (5 mg/kg bw/day treatments (3 and 9 weeks, respectively. Renal function was assessed on serum and urine; kidney tissue was used for histopathological characterization and gene and/or protein expression of markers of proliferation, fibrosis and inflammation. In the short-term, creatinine and blood urea nitrogen (BUN levels increased and clearances decreased, accompanied by glomerular filtration rate (GFR reduction, but without kidney lesions; at that stage, CsA exposure induced proliferating cell nuclear antigen (PCNA, transforming growth factor beta 1 (TGF-β1, factor nuclear kappa B (NF-κβ and Tumor Protein P53 (TP53 kidney mRNA up-regulation. In the long-term treatment, renal dysfunction data was accompanied by glomerular and tubulointerstitial lesions, with remarkable kidney mRNA up-regulation of the mammalian target of rapamycin (mTOR and the antigen identified by monoclonal antibody Ki-67 (Mki67, accompanied by mTOR protein overexpression. Transition from CsA-induced renal dysfunction to nephrotoxicity is accompanied by modification of molecular mechanisms and biomarkers, being mTOR one of the key players for kidney lesion evolution, thus suggesting, by mean of molecular evidences, that early CsA replacement by mTOR inhibitors is indeed the better therapeutic choice to prevent chronic allograft nephropathy.

  4. Induced magnetism in transition metal intercalated graphitic systems

    KAUST Repository

    Kaloni, Thaneshwor P.

    2011-10-26

    We investigate the structure, chemical bonding, electronic properties, and magnetic behavior of a three-dimensional graphitic network in aba and aaa stacking with intercalated transition metal atoms (Mn, Fe, Co, Ni, and Cu). Using density functional theory, we find induced spin-polarization of the C atoms both when the graphene sheets are aba stacked (forming graphite) and aaa stacked (resembling bi-layer graphene). The magnetic moment induced by Mn, Fe, and Co turns out to vary from 1.38 μB to 4.10 μB, whereas intercalation of Ni and Cu does not lead to a magnetic state. The selective induction of spin-polarization can be utilized in spintronic and nanoelectronic applications.

  5. The crisis induced by the property transition of a system

    Institute of Scientific and Technical Information of China (English)

    Dai Jun; Wang Wen-Xiu; Jiang Yu-Mei; He Yue; Chen Wen; He Da-Ren

    2005-01-01

    A simultaneous transition in the property of a system from everywhere smooth and conservative to piecewise smooth and quasi-dissipative is observed in a kicked billiard when adjusting a single controlling parameter. The transition induces a special kind of crisis, which signifies a sudden change of a typical conservative stochastic web into a transient web formed by the forward image set of the discontinuity borderline of the system function. Iterations on the transient web finally fall in an escaping hole composed of an elliptic island chain, which appears right after the threshold of the property transition. The size of the hole becomes larger as the controlling parameter increases so that the iterations escape faster. The averaged lifetime of the iterations in the transient web therefore follows a power-law with a special scaling exponent. At the same time, a fat fractal forbidden web, which appears also at the threshold,grows up and cuts off more and more parts from the original conservative stochastic web so that the remnant transient web becomes thinner and thinner. We numerically show that another power law can also describe this.

  6. Pressure induced phase transition behaviour in -electron based dialuminides

    Indian Academy of Sciences (India)

    P Ch Sahu; N V Chandra Shekar

    2000-05-01

    The rare-earth and actinide based compounds are endowed with several exotic physical and chemical properties due to the presence of -electrons. These properties exhibit interesting changes under the action of various thermodynamic fields and hence continues to be a subject of extensive research. For instance, under pressure, the nature of -electrons can be changed from localized to itinerant, leading to a variety of changes in their structural, physical and chemical properties. The present review on the high pressure phase transition behaviour of dialuminides of rare earths and actinides is an outcome of research in our laboratory during the last five years using a unique combination of a Guinier diffractometer and a diamond anvil cell built in-house. To bring out the correlations between the compressibility and structural behaviour with the electronic structure, we have also carried out electronic structure calculation. Further, the usefulness of Villars' three parameter structure maps in predicting pressure induced structural transitions has been explored and this has been illustrated with the available phase transition data.

  7. Impact-Induced Glass Transition in Elastomeric Coatings

    Science.gov (United States)

    Roland, C. M.

    2013-03-01

    When an elastomer layer is applied to the front surface of steel, the resistance to penetration by hard projectiles increases significantly. It is not obvious why a soft polymer should affect this property of metals, and most rubbers do not. However, we have found that a few are very effective; the requirement is that the polymer undergo a viscoelastic phase transition upon impact. This means that the frequency of its segmental dynamics correspond to the impact frequency. The latter is estimated as the ratio of the projectile velocity to the coating thickness, and is on the order of 105 s-1 for the experiments herein. Our data and a non-linear dynamics finite-element analysis offer support for this resonance condition as a primary mechanism underlying the penetration-resistance of elastomer-coated metal substrates. The impact-induced phase transition causes large energy absorption, decreasing the kinetic energy of the impacting projectile. However, this energy absorption only accounts for about half the enhanced stopping power of the elastomer/steel bilayer. An additional mechanism is lateral spreading of the impact force, resulting from the transient hardening of the elastomeric during its transition to the glassy state - the modulus of the rubber increases 1000-fold over a time period of microseconds. The penetration-resistance is a very nonlinear function of the coating thickness. Moreover, tests on various metals show that hardness is the principal substrate parameter controlling the contribution of the coating. This work was supported by the Office of Naval Research.

  8. Gamma radiation induced changes in nuclear waste glass containing Eu

    Science.gov (United States)

    Mohapatra, M.; Kadam, R. M.; Mishra, R. K.; Kaushik, C. P.; Tomar, B. S.; Godbole, S. V.

    2011-10-01

    Gamma radiation induced changes were investigated in sodium-barium borosilicate glasses containing Eu. The glass composition was similar to that of nuclear waste glasses used for vitrifying Trombay research reactor nuclear waste at Bhabha Atomic Research Centre, India. Photoluminescence (PL) and electron paramagnetic resonance (EPR) techniques were used to study the speciation of the rare earth (RE) ion in the matrix before and after gamma irradiation. Judd-Ofelt ( J- O) analyses of the emission spectra were done before and after irradiation. The spin counting technique was employed to quantify the number of defect centres formed in the glass at the highest gamma dose studied. PL data suggested the stabilisation of the trivalent RE ion in the borosilicate glass matrix both before and after irradiation. It was also observed that, the RE ion distributes itself in two different environments in the irradiated glass. From the EPR data it was observed that, boron oxygen hole centre based radicals are the predominant defect centres produced in the glass after irradiation along with small amount of E’ centres. From the spin counting studies the concentration of defect centres in the glass was calculated to be 350 ppm at 900 kGy. This indicated the fact that bulk of the glass remained unaffected after gamma irradiation up to 900 kGy.

  9. TGF-β-induced epithelial to mesenchymal transition

    Institute of Scientific and Technical Information of China (English)

    Jian Xu; Samy Lamouille; Rik Derynck

    2009-01-01

    During development and in the context of different morphogenetic events, epithelial cells undergo a process called epithelial to mesenchymal transition or transdifferentiation (EMT). In this process, the cells lose their epithelial characteristics, including their polarity and specialized cell-cell contacts, and acquire a migratory behavior, allowing them to move away from their epithelial cell community and to integrate into surrounding tissue, even at remote locations. EMT illustrates the differentiation plasticity during development and is complemented by another process,called mesenchymal to epithelial transition (MET). While being an integral process during development, EMT is also recapitulated under pathological conditions, prominently in fibrosis and in invasion and metastasis of carcinomas.Accordingly, EMT is considered as an important step in tumor progression. TGF-β signaling has been shown to play an important role in EMT. In fact, adding TGF-β to epithelial cells in culture is a convenient way to induce EMT in various epithelial cells. Although much less characterized, epithelial plasticity can also be regulated by TGF-β-related bone morphogenetic proteins (BMPs), and BMPs have been shown to induce EMT or MET depending on the developmental context. In this review, we will discuss the induction of EMT in response to TGF-β, and focus on the underlying signaling and transcription mechanisms.

  10. Detecting special nuclear material using muon-induced neutron emission

    Energy Technology Data Exchange (ETDEWEB)

    Guardincerri, Elena; Bacon, Jeffrey; Borozdin, Konstantin; Matthew Durham, J.; Fabritius II, Joseph [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Hecht, Adam [University of New Mexico, Albuquerque, NM 87131 (United States); Milner, Edward C. [Southern Methodist University, Dallas, TX 75205 (United States); Miyadera, Haruo; Morris, Christopher L. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Perry, John [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); University of New Mexico, Albuquerque, NM 87131 (United States); Poulson, Daniel [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2015-07-21

    The penetrating ability of cosmic ray muons makes them an attractive probe for imaging dense materials. Here, we describe experimental results from a new technique that uses neutrons generated by cosmic-ray muons to identify the presence of special nuclear material (SNM). Neutrons emitted from SNM are used to tag muon-induced fission events in actinides and laminography is used to form images of the stopping material. This technique allows the imaging of SNM-bearing objects tagged using muon tracking detectors located above or to the side of the objects, and may have potential applications in warhead verification scenarios. During the experiment described here we did not attempt to distinguish the type or grade of the SNM.

  11. Homocysteine-induced apoptosis in endothelial cells coincides with nuclear NOX2 and peri-nuclear NOX4 activity.

    Science.gov (United States)

    Sipkens, Jessica A; Hahn, Nynke; van den Brand, Carlien S; Meischl, Christof; Cillessen, Saskia A G M; Smith, Desirée E C; Juffermans, Lynda J M; Musters, René J P; Roos, Dirk; Jakobs, Cornelis; Blom, Henk J; Smulders, Yvo M; Krijnen, Paul A J; Stehouwer, Coen D A; Rauwerda, Jan A; van Hinsbergh, Victor W M; Niessen, Hans W M

    2013-11-01

    Apoptosis of endothelial cells related to homocysteine (Hcy) has been reported in several studies. In this study, we evaluated whether reactive oxygen species (ROS)-producing signaling pathways contribute to Hcy-induced apoptosis induction, with specific emphasis on NADPH oxidases. Human umbilical vein endothelial cells were incubated with 0.01-2.5 mM Hcy. We determined the effect of Hcy on caspase-3 activity, annexin V positivity, intracellular NOX1, NOX2, NOX4, and p47(phox) expression and localization, nuclear nitrotyrosine accumulation, and mitochondrial membrane potential (ΔΨ m). Hcy induced caspase-3 activity and apoptosis; this effect was concentration dependent and maximal after 6-h exposure to 2.5 mM Hcy. It was accompanied by a significant increase in ΔΨ m. Cysteine was inactive on these parameters excluding a reactive thiol group effect. Hcy induced an increase in cellular NOX2, p47(phox), and NOX4, but not that of NOX1. 3D digital imaging microscopy followed by image deconvolution analysis showed nuclear accumulation of NOX2 and p47(phox) in endothelial cells exposed to Hcy, but not in control cells, which coincided with accumulation of nuclear nitrotyrosine residues. Furthermore, Hcy enhanced peri-nuclear localization of NOX4 coinciding with accumulation of peri-nuclear nitrotyrosine residues, a reflection of local ROS production. p47(phox) was also increased in the peri-nuclear region. The Hcy-induced increase in caspase-3 activity was prevented by DPI and apocynin, suggesting involvement of NOX activity. The data presented in this article reveal accumulation of nuclear NOX2 and peri-nuclear NOX4 accumulation as potential source of ROS production in Hcy-induced apoptosis in endothelial cells.

  12. Investigation of Nuclear Phase Transition by Solvababe supersymmetric algebraic model and its application in Ru-Rh and Zn-Cu Isotopes

    CERN Document Server

    Jafarizadeh, M A; Fouladi, N; Ranjbar, Z; Sadighzadeh, A

    2016-01-01

    Solvable supersymmetric algebraic model for descriptions of the spherical to gama unstable shape- phase transition in even and odd mass nuclei is proposed. This model is based on dual algebraic structure and Richardson - Gaudin method, where the duality relations between the unitary and quasispin algebraic structures for the boson and fermion systems are extended to mixed boson- fermion system. The structure of two type of nuclear supersymmetry schemes, based on the U(6/2) and U(6/4) supergroups, is discussed. We investigate the change in level structure induced by the phase transition by doing a quantal analysis. By using the generalized quasispin algebra, it is shown that the nuclear supersymmetry concept can be also used for transitional regions in addition to dynamical symmetry limits. Experimental evidence for the U(5)-O(6) transition in Ru-Rh and Zn- Cu supermultiplets is presented. The low-states energy spectra and B(E2)values for these nuclei have been calculated and compared with the experimental dat...

  13. Prm3p is a pheromone-induced peripheral nuclear envelope protein required for yeast nuclear fusion.

    Science.gov (United States)

    Shen, Shu; Tobery, Cynthia E; Rose, Mark D

    2009-05-01

    Nuclear membrane fusion is the last step in the mating pathway of the yeast Saccharomyces cerevisiae. We adapted a bioinformatics approach to identify putative pheromone-induced membrane proteins potentially required for nuclear membrane fusion. One protein, Prm3p, was found to be required for nuclear membrane fusion; disruption of PRM3 caused a strong bilateral defect, in which nuclear congression was completed but fusion did not occur. Prm3p was localized to the nuclear envelope in pheromone-responding cells, with significant colocalization with the spindle pole body in zygotes. A previous report, using a truncated protein, claimed that Prm3p is localized to the inner nuclear envelope. Based on biochemistry, immunoelectron microscopy and live cell microscopy, we find that functional Prm3p is a peripheral membrane protein exposed on the cytoplasmic face of the outer nuclear envelope. In support of this, mutations in a putative nuclear localization sequence had no effect on full-length protein function or localization. In contrast, point mutations and deletions in the highly conserved hydrophobic carboxy-terminal domain disrupted both protein function and localization. Genetic analysis, colocalization, and biochemical experiments indicate that Prm3p interacts directly with Kar5p, suggesting that nuclear membrane fusion is mediated by a protein complex.

  14. Enhanced spin-dependent parity non-conservation effect in the $7s {}^2S_{1/2} \\to 6d {}^2D_{5/2}$ transition in Fr: A possibility for unambiguous detection of nuclear anapole moment

    CERN Document Server

    Sahoo, B K; Das, B P; Sakemi, Y

    2015-01-01

    Employing the relativistic coupled-cluster method, comparative studies of the parity non-conserving electric dipole amplitudes for the $7s \\ ^2S_{1/2} \\rightarrow 6d \\ ^2D_{5/2}$ transitions in $^{210}$Fr and $^{211}$Fr isotopes have been carried out. It is found that these transition amplitudes, sensitive only to the nuclear spin dependent effects, are enhanced by more than 3 orders compared to the low-lying $S-D_{5/2}$ transitions in Ba$^+$ and Ra$^+$ owing to the very large contributions from the electron core-polarization effects in Fr. This translates to a relatively large and, in principle, measurable induced light shift, which would be a signature of nuclear spin dependent parity nonconservation that is dominated by the nuclear anapole moment in a heavy atom like Fr. A plausible scheme to measure this quantity using the Cyclotron and Radioisotope Center (CYRIC) facility at Tohoku University has been outlined.

  15. Observation of strongly forbidden solid effect dynamic nuclear polarization transitions via electron-electron double resonance detected NMR

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Albert A.; Corzilius, Björn; Haze, Olesya; Swager, Timothy M.; Griffin, Robert G., E-mail: rgg@mit.edu [Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

    2013-12-07

    We present electron paramagnetic resonance experiments for which solid effect dynamic nuclear polarization transitions were observed indirectly via polarization loss on the electron. This use of indirect observation allows characterization of the dynamic nuclear polarization (DNP) process close to the electron. Frequency profiles of the electron-detected solid effect obtained using trityl radical showed intense saturation of the electron at the usual solid effect condition, which involves a single electron and nucleus. However, higher order solid effect transitions involving two, three, or four nuclei were also observed with surprising intensity, although these transitions did not lead to bulk nuclear polarization—suggesting that higher order transitions are important primarily in the transfer of polarization to nuclei nearby the electron. Similar results were obtained for the SA-BDPA radical where strong electron-nuclear couplings produced splittings in the spectrum of the indirectly observed solid effect conditions. Observation of high order solid effect transitions supports recent studies of the solid effect, and suggests that a multi-spin solid effect mechanism may play a major role in polarization transfer via DNP.

  16. Observation of strongly forbidden solid effect dynamic nuclear polarization transitions via electron-electron double resonance detected NMR.

    Science.gov (United States)

    Smith, Albert A; Corzilius, Björn; Haze, Olesya; Swager, Timothy M; Griffin, Robert G

    2013-12-01

    We present electron paramagnetic resonance experiments for which solid effect dynamic nuclear polarization transitions were observed indirectly via polarization loss on the electron. This use of indirect observation allows characterization of the dynamic nuclear polarization (DNP) process close to the electron. Frequency profiles of the electron-detected solid effect obtained using trityl radical showed intense saturation of the electron at the usual solid effect condition, which involves a single electron and nucleus. However, higher order solid effect transitions involving two, three, or four nuclei were also observed with surprising intensity, although these transitions did not lead to bulk nuclear polarization--suggesting that higher order transitions are important primarily in the transfer of polarization to nuclei nearby the electron. Similar results were obtained for the SA-BDPA radical where strong electron-nuclear couplings produced splittings in the spectrum of the indirectly observed solid effect conditions. Observation of high order solid effect transitions supports recent studies of the solid effect, and suggests that a multi-spin solid effect mechanism may play a major role in polarization transfer via DNP.

  17. Onset transition to cold nuclear matter from lattice QCD with heavy quarks.

    Science.gov (United States)

    Fromm, M; Langelage, J; Lottini, S; Neuman, M; Philipsen, O

    2013-03-22

    Lattice QCD at finite density suffers from a severe sign problem, which has so far prohibited simulations of the cold and dense regime. Here we study the onset of nuclear matter employing a three-dimensional effective theory derived by combined strong coupling and hopping expansions, which is valid for heavy but dynamical quarks and has a mild sign problem only. Its numerical evaluations agree between a standard Metropolis and complex Langevin algorithm, where the latter is free of the sign problem. Our continuum extrapolated data approach a first order phase transition at μ(B) ≈ m(B) as the temperature approaches zero. An excellent description of the data is achieved by an analytic solution in the strong coupling limit.

  18. Bubble dynamics and the quark-hadron phase transition in nuclear collisions

    CERN Document Server

    Fogaça, D A; Fariello, R; Navarra, F S

    2016-01-01

    We study the nucleation of a quark gluon plasma (QGP) phase in a hadron gas at low temperatures and high baryon densities. This kind of process will presumably happen very often in nuclear collisions at FAIR and NICA. When the right energy density (or baryon density) is reached the conversion of one phase into another is not instantaneous. It is a complex process, which involves the nucleation of bubbles of the new phase. One important element of this transition process is the rate of growth of a QGP bubble. In order to estimate it we solve the Relativistic Rayleigh$-$Plesset equation which governs the dynamics of a relativistic spherical bubble in a cold and strongly interacting medium. The baryon rich hadron gas is represented by the nonlinear Walecka model and the QGP is described by the MIT bag model and also by a mean field model of QCD.

  19. The fragile-to-strong dynamic crossover transition in confined water: nuclear magnetic resonance results

    Science.gov (United States)

    Mallamace, F.; Broccio, M.; Corsaro, C.; Faraone, A.; Wanderlingh, U.; Liu, L.; Mou, C.-Y.; Chen, S. H.

    2006-04-01

    By means of a nuclear magnetic resonance experiment, we give evidence of the existence of a fragile-to-strong dynamic crossover transition (FST) in confined water at a temperature TL=223±2K. We have studied the dynamics of water contained in 1D cylindrical nanoporous matrices (MCM-41-S) in the temperature range 190-280K, where experiments on bulk water were so far hampered by crystallization. The FST is clearly inferred from the T dependence of the inverse of the self-diffusion coefficient of water (1/D) as a crossover point from a non-Arrhenius to an Arrhenius behavior. The combination of the measured self-diffusion coefficient D and the average translational relaxation time ⟨τT⟩, as measured by neutron scattering, shows the predicted breakdown of Stokes-Einstein relation in deeply supercooled water.

  20. The fragile-to-strong dynamic crossover transition in confined water: nuclear magnetic resonance results.

    Science.gov (United States)

    Mallamace, F; Broccio, M; Corsaro, C; Faraone, A; Wanderlingh, U; Liu, L; Mou, C-Y; Chen, S H

    2006-04-28

    By means of a nuclear magnetic resonance experiment, we give evidence of the existence of a fragile-to-strong dynamic crossover transition (FST) in confined water at a temperature T(L)=223+/-2 K. We have studied the dynamics of water contained in 1D cylindrical nanoporous matrices (MCM-41-S) in the temperature range 190-280 K, where experiments on bulk water were so far hampered by crystallization. The FST is clearly inferred from the T dependence of the inverse of the self-diffusion coefficient of water (1D) as a crossover point from a non-Arrhenius to an Arrhenius behavior. The combination of the measured self-diffusion coefficient D and the average translational relaxation time tau(T), as measured by neutron scattering, shows the predicted breakdown of Stokes-Einstein relation in deeply supercooled water.

  1. Technical Approach and Plan for Transitioning Spent Nuclear Fuel (SNF) Project Facilities to the Environmental Restoration Program

    Energy Technology Data Exchange (ETDEWEB)

    SKELLY, W.A.

    1999-10-06

    This document describes the approach and process in which the 100-K Area Facilities are to be deactivated and transitioned over to the Environmental Restoration Program after spent nuclear fuel has been removed from the K Basins. It describes the Transition Project's scope and objectives, work breakdown structure, activity planning, estimated cost, and schedule. This report will be utilized as a planning document for project management and control and to communicate details of project content and integration.

  2. A space bourne crystal diffraction telescope for the energy range of nuclear transitions

    Energy Technology Data Exchange (ETDEWEB)

    von Ballmoos, P.; Naya, J.E.; Albernhe, F.; Vedrenne, G. [Centre d`Etude Spatial des Rayonnements, Toulouse (France); Smither, R.K.; Faiz, M.; Fernandez, P.; Graber, T. [Argonne National Lab., IL (United States)

    1995-10-01

    Recent experimental work of the Toulouse-Argonne collaboration has opened for perspective of a focusing gamma-ray telescope operating in the energy range of nuclear transitions, featuring unprecedented sensitivity, angular and energy resolution. The instrument consists of a tunable crystal diffraction lens situated on a stabilized spacecraft, focusing gamma-rays onto a small array of Germanium detectors perched on an extendible boom. While the weight of such an instrument is less than 500 kg, it features an angular resolution of 15 in., an energy resolution of 2 keV and a 3 {sigma} narrow line sensitivity of a few times 10{sup {minus}7} photons s{sup {minus}1} cm{sup {minus}2} (10{sup 6} sec observation). This instrumental concept permits observation of any identified source at any selected line-energy in a range of typically 200 keV to 1300 keV. The resulting ``sequential`` operation mode makes sites of explosive nucleosynthesis natural scientific objectives for such a telescope: the nuclear lines of extragalactic supernovae ({sup 56}Ni, {sup 44}Ti, {sup 60}Fe) and galactic novae (p{sup {minus}}p{sup +} line, {sup 7}Be) are accessible to observation, one at a time, due to the erratic appearance and the sequence of half-lifes of these events. Other scientific objectives, include the narrow 511 keV line from galactic broad class annihilators (such as 1E1740-29, nova musca) and possible redshifted annihilation lines from AGN`s.

  3. Nuclear Thermal Propulsion (NTP): A Proven, Growth Technology for Fast Transit Human Missions to Mars

    Science.gov (United States)

    Borowski, Stanley K.; McCurdy, David R.; Packard, Thomas W.

    2014-01-01

    The "fast conjunction" long surface stay mission option was selected for NASA's recent Mars Design Reference Architecture (DRA) 5.0 study because it provided adequate time at Mars (approx. 540 days) for the crew to explore the planet's geological diversity while also reducing the "1-way" transit times to and from Mars to approx. 6 months. Short transit times are desirable in order to reduce the debilitating physiological effects on the human body that can result from prolonged exposure to the zero-gravity (0-gE) and radiation environments of space. Recent measurements from the RAD detector attached to the Curiosity rover indicate that astronauts would receive a radiation dose of approx. 0.66 Sv (approx. 66 rem)-the limiting value established by NASA-during their 1-year journey in deep space. Proven nuclear thermal rocket (NTR) technology, with its high thrust and high specific impulse (Isp approx. 900 s), can cut 1-way transit times by as much as 50 percent by increasing the propellant capacity of the Mars transfer vehicle (MTV). No large technology scale-ups in engine size are required for these short transit missions either since the smallest engine tested during the Rover program-the 25 klbf "Pewee" engine is sufficient when used in a clustered arrangement of three to four engines. The "Copernicus" crewed MTV developed for DRA 5.0 is a 0-gE design consisting of three basic components: (1) the NTP stage (NTPS); (2) the crewed payload element; and (3) an integrated "saddle truss" and LH2 propellant drop tank assembly that connects the two elements. With a propellant capacity of approx. 190 t, Copernicus can support 1-way transit times ranging from approx. 150 to 220 days over the 15-year synodic cycle. The paper examines the impact on vehicle design of decreasing transit times for the 2033 mission opportunity. With a fourth "upgraded" SLS/HLV launch, an "in-line" LH2 tank element can be added to Copernicus allowing 1-way transit times of 130 days. To achieve 100

  4. TGF-β induced epithelial-mesenchymal transition modeling

    Science.gov (United States)

    Xenitidis, P.; Seimenis, I.; Kakolyris, S.; Adamopoulos, A.

    2015-09-01

    Epithelial cells may undergo a process called epithelial to mesenchymal transition (EMT). During EMT, cells lose their epithelial characteristics and acquire a migratory ability. Transforming growth factor-beta (TGF-β) signaling is considered to play an important role in EMT by regulating a set of genes through a gene regulatory network (GRN). This work aims at TGF-β induced EMT GRN modeling using publicly available experimental data (gene expression microarray data). The time-series network identification (TSNI) algorithm was used for inferring the EMT GRN. Receiver operating characteristic (ROC) and precision-recall (P-R) curves were constructed and the areas under them were used for evaluating the algorithm performance regarding network inference.

  5. Field induced phase transition in the few photon regime

    CERN Document Server

    Panferov, A D; Titov, A I; Kaempfer, B; Otto, A; Blaschke, D B; Juchnowski, L

    2016-01-01

    Some features of the field induced phase transition accompanied by the vacuum creation of an electron-positron plasma (EPP) in strong time-dependent electric fields have been discussed in the work [1] in the domain of the tunneling mechanism ($\\omega \\ll m$, where $\\omega$ is the characteristic frequency of the external field and $m$ is the electron mass). In the present contribution the features of the this process will be considered in the few photon domain where $\\omega \\sim m$. We observe a narrowing of the transient domain of the fast oscillations and, mainly, a considerable growth of the effectiveness of the EPP production. Under these circumstances, we see an increase of the effectiveness of the EPP creation in the particular case of a bifrequent excitation, where both mechanisms (tunneling and few photon) act simultaneously [2,3].

  6. Noise-induced transitions in rugged energy landscapes

    Science.gov (United States)

    Duncan, A. B.; Kalliadasis, S.; Pavliotis, G. A.; Pradas, M.

    2016-09-01

    We consider the problem of an overdamped Brownian particle moving in multiscale potential with N +1 characteristic length scales: the macroscale and N separated microscales. We show that the coarse-grained dynamics is given by an overdamped Langevin equation with respect to the free energy and with a space-dependent diffusion tensor, the calculation of which requires the solution of N fully coupled Poisson equations. We study in detail the structure of the bifurcation diagram for one-dimensional problems, and we show that the multiscale structure in the potential leads to hysteresis effects and to noise-induced transitions. Furthermore, we obtain an explicit formula for the effective diffusion coefficient for a self-similar separable potential, and we investigate the limit of infinitely many small scales.

  7. Solid-solid transitions induced by repulsive interactions revisited

    Science.gov (United States)

    Navascués, G.; Velasco, E.; Mederos, L.

    2016-10-01

    We revisit a problem already studied 15 years ago by us in collaboration with Stell and Hemmer: the isostructural solid-solid transitions induced by repulsive particle interactions exhibited by classical systems interacting via the Stell-Hemmer potentials. The full phase diagram in the crystal region is obtained by applying a perturbation theory for classical solids used during our collaboration with Stell. Also, the performance of such a theory is now tested by comparing the perturbative phase diagram with that obtained from computer simulations. The latter was calculated using a recently refined method to obtain the free-energy of crystals by means of Monte Carlo simulations. The perturbation theory captures the correct topology and correctly identifies the stable, fcc and bcc, phases. In addition, the theory predicts the occurrence of special points: a point where the two stable structures coexist at the same density, and two critical points terminating the corresponding isostructural phase transitions for fcc and bcc phases. The location of some of these features in the phase diagram is predicted almost quantitatively. However, phase boundaries involving the non-compact bcc phase are much less accurate, a problem that can be traced to the poor representation used for the bcc phase of the reference, hard-sphere, system.

  8. Strain-induced topological quantum phase transition in phosphorene oxide

    Science.gov (United States)

    Kang, Seoung-Hun; Park, Jejune; Woo, Sungjong; Kwon, Young-Kyun

    Using ab initio density functional theory, we investigate the structural stability and electronic properties of phosphorene oxides (POx) with different oxygen compositions x. A variety of configurations are modeled and optimized geometrically to search for the equilibrium structure for each x value. Our electronic structure calculations on the equilibrium configuration obtained for each x reveal that the band gap tends to increase with the oxygen composition of x 0.5. We further explore the strain effect on the electronic structure of the fully oxidized phosphorene, PO, with x = 1. At a particular strain without spin-orbit coupling (SOC) is observed a band gap closure near the Γ point in the k space. We further find the strain in tandem with SOC induces an interesting band inversion with a reopened very small band gap (5 meV), and thus gives rise to a topological quantum phase transition from a normal insulator to a topological insulator. Such a topological phase transition is confirmed by the wave function analysis and the band topology identified by the Z2 invariant calculation.

  9. Pressure-Induced Phase Transition in Weyl Semimetallic WTe2.

    Science.gov (United States)

    Xia, Juan; Li, Dong-Fei; Zhou, Jia-Dong; Yu, Peng; Lin, Jun-Hao; Kuo, Jer-Lai; Li, Hai-Bo; Liu, Zheng; Yan, Jia-Xu; Shen, Ze-Xiang

    2017-08-28

    Tungsten ditelluride (WTe2 ) is a semimetal with orthorhombic Td phase that possesses some unique properties such as Weyl semimetal states, pressure-induced superconductivity, and giant magnetoresistance. Here, the high-pressure properties of WTe2 single crystals are investigated by Raman microspectroscopy and ab initio calculations. WTe2 shows strong plane-parallel/plane-vertical vibrational anisotropy, stemming from its intrinsic Raman tensor. Under pressure, the Raman peaks at ≈120 cm(-1) exhibit redshift, indicating structural instability of the orthorhombic Td phase. WTe2 undergoes a phase transition to a monoclinic T' phase at 8 GPa, where the Weyl states vanish in the new T' phase due to the presence of inversion symmetry. Such Td to T' phase transition provides a feasible method to achieve Weyl state switching in a single material without doping. The new T' phase also coincides with the appearance of superconductivity reported in the literature. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. High field nuclear magnetic resonance in transition metal substituted BaFe2As2

    Science.gov (United States)

    Garitezi, T. M.; Lesseux, G. G.; Rosa, P. F. S.; Adriano, C.; Reyes, A. P.; Kuhns, P. L.; Pagliuso, P. G.; Urbano, R. R.

    2014-05-01

    We report high field 75As nuclear magnetic resonance (NMR) measurements on Co and Cu substituted BaFe2As2 single crystals displaying same structural/magnetic transition T0≃128 K. From our anisotropy studies in the paramagnetic state, we strikingly found virtually identical quadrupolar splitting and consequently the quadrupole frequency νQ≃2.57(1) MHz for both compounds, despite the claim that each Cu delivers 2 extra 3d electrons in BaFe2As2 compared to Co substitution. These results allow us to conclude that a subtle change in the crystallographic structure, particularly in the Fe-As tetrahedra, must be the most probable tuning parameter to determine T0 in this class of superconductors rather than electronic doping. Furthermore, our NMR data around T0 suggest coexistence of tetragonal/paramagnetic and orthorhombic/antiferromagnetic phases between the structural and the spin density wave magnetic phase transitions, similarly to what was reported for K-doped BaFe2As2 [Urbano et al., Phys. Rev. Lett. 105, 107001 (2010)].

  11. Pressure-induced phase transition and polymerization of tetracyanoethylene (TCNE)

    Science.gov (United States)

    Tomasino, Dane; Chen, Jing-Yin; Kim, Minesob; Yoo, Choong-Shik

    2013-03-01

    We have studied the pressure-induced physical and chemical transformations of tetracyanoethylene (TCNE or C6N4) in diamond anvil cells using micro-Raman spectroscopy, laser-heating, emission spectroscopy, and synchrotron x-ray diffraction. The results indicate that TCNE in a quasi-hydrostatic condition undergoes a shear-induced phase transition at 10 GPa and then a chemical change to two-dimensional (2D) C=N polymers above 14 GPa. These phase and chemical transformations depend strongly on the state of stress in the sample and occur sluggishly in non-hydrostatic conditions over a large pressure range between 7 and 14 GPa. The x-ray diffraction data indicate that the phase transition occurs isostructurally within the monoclinic structure (P21/c) without any apparent volume discontinuity and the C=N polymer is highly disordered but remains stable to 60 GPa—the maximum pressure studied. On the other hand, laser-heating of the C=N polymer above 25 GPa further converts to a theoretically predicted 3D C-N network structure, evident from an emergence of new Raman νs(C-N) at 1404 cm-1 at 25 GPa and the visual appearance of translucent solid. The C-N product is, however, unstable upon pressure unloading below 10 GPa, resulting in a grayish powder that can be considered as nano-diamonds with high-nitrogen content at ambient pressure. The C-N product shows a strong emission line centered at 640 nm at 30 GPa, which linearly shifts toward shorter wavelength at the rate of -1.38 nm/GPa. We conjecture that the observed red shift upon unloading pressure is due to increase of defects in the C-N product and thereby weakening of C-N bonds.

  12. Pressure-Induced Phase Transitions In Gadolinium Iron Borate

    Science.gov (United States)

    Kharlamova, S. A.; Struzhkin, V. V.; Sinogeikin, S. V.; Gavriliuk, A. G.; Brown, D.; Toellner, T.; Zhao, J.; Lerche, M.; Lyubutin, I. S.; Ovchinnikov, S. G.; Alp, E. E.; Sturhahn, W.

    2007-12-01

    An understanding of spin crossover (SC) dynamics is relevant to understanding of a role or participation of SC in natural systems including lower Mantle minerals, heme proteins as well as from fundamental science of view. For example, pressure-induced electronic spin transitions of Fe2+ and Fe3+ iron occur in magnesiowustite, silicate perovskite and post-perovskite which are abundant minerals in the Earth's lower mantle [1-3]. Such a SC phenomenon has recently been observed in a number of magnetic minerals FeBO3 [4, 5], BiFeO3 [6], Fe2O3 [7], and Y3Fe5O12 [8], (La, Pr)FeO3 [9, 10]. In those cases, iron ions are in the trivalent state Fe3+ and the high-spin-low-spin (HS-LS) crossover is manifested as the collapse of the local magnetic moment and as the transition of the antiferromagnet to a paramagnetic state. For example, in FeBO3 at low temperatures a spin-crossover and some magnetic transitions with two triple points were found [4, 5]. Gadolinium iron borate, GdFe3(BO3)4 is also a system with SEC and recently, we have reported on phase transitions induced by high pressures in this material [11, 12]. We studied the structural and magnetic behavior of GdFe573(BO3)4 at high pressures and temperatures using a diamond anvil cell and a Synchrotron Mossbauer Spectroscopy technique. The hyperfine parameters and results obtained from the experiments are discussed. Based on our experimental data and theoretical calculation a tentative magnetic P-T phase diagram and an equation of states of GdFe573(BO3)4 are proposed. Important features of the phase diagram are a spin crossover, insulator-semiconductor transition and possible presence of two triple points where magnetic and paramagnetic phases of the high-spin and low-spin states coexist. 1. J. Badro, J.-P. Rueff, G. Vankó, et al., Science 305, 383 (2004). 2. J. M. Jackson, W. Sturhahn, G. Shen, et al., American Mineralogist 90, 199 (2005). 3. J.Li, V.V. Struzhkin, H.-K. Mao, et al., PNAS 101, 14027 (2004). 4. I.A. Troyan

  13. 2nd International Workshop on Desorption Induced by Electronic Transitions

    CERN Document Server

    Menzel, Dietrich

    1985-01-01

    The second workshop on Desorption Induced by Electronic Transitions (DIET II) took place October 15-17, 1984, in SchloB Elmau, Bavaria. DIET II, fol­ lowing the great success of DIET I (edited by N. H. Tolk, M. M. Traum, J. C. Tully, T. E. Madey and published in Springer Ser. Chem. Phys. , Vol. 24), again brought together over 60 workers in this exciting field. The "hard co­ re of experts" was essentially the same as in DIET I but the general overlap of participants between the two meetings was small. While DIET I had the function of an exposition of the status of the field DIET II focussed more on new developments. The main emphasis was again on the microscopic under­ standing of DIET but a number of side aspects and the application of DIET ideas to other fields such as sputtering, laser-induced desorption, fractu­ re, erosion, etc. were considered, too. New mechanisms and new refined expe­ rimental techniques were proposed and discussed at the meeting critically but with great enthusiasm. In addition t...

  14. Influence of the nuclear equation of state on the hadron-quark phase transition in neutron stars

    Institute of Scientific and Technical Information of China (English)

    YANG Fang; SHEN Hong

    2008-01-01

    We study the hadron-quark phase transition in the interior of neutron stars, and examine the influence of the nuclear equation of state on the phase transition and neutron star properties. The relativistic mean field theory with several parameter sets is used to construct the nuclear equation of state, while the Nambu-Jona-Lasinio model is used for the description of the deconfined quark phase. Our results show that a harder nuclear equation of state leads to an earlier onset of a mixed phase of hadronic and quark matter. We find that a massive neutron star possesses a mixed phase core, but it is not dense enough to possess a pure quark core.

  15. Nuclear Fusion Effects Induced in Intense Laser-Generated Plasmas

    Directory of Open Access Journals (Sweden)

    Lorenzo Torrisi

    2013-01-01

    Full Text Available Deutered polyethylene (CD2n thin and thick targets were irradiated in high vacuum by infrared laser pulses at 1015W/cm2 intensity. The high laser energy transferred to the polymer generates plasma, expanding in vacuum at supersonic velocity, accelerating hydrogen and carbon ions. Deuterium ions at kinetic energies above 4 MeV have been measured by using ion collectors and SiC detectors in time-of-flight configuration. At these energies the deuterium–deuterium collisions may induce over threshold fusion effects, in agreement with the high D-D cross-section valuesaround 3 MeV energy. At the first instants of the plasma generation, during which high temperature, density and ionacceleration occur, the D-D fusions occur as confirmed by the detection of mono-energetic protonsand neutrons with a kinetic energy of 3.0 MeV and 2.5 MeV, respectively, produced by the nuclear reaction. The number of fusion events depends strongly on the experimental set-up, i.e. on the laser parameters (intensity, wavelength, focal spot dimension, target conditions (thickness, chemical composition, absorption coefficient, presence of secondary targets and used geometry (incidence angle, laser spot, secondary target positions.A number of D-D fusion events of the order of 106÷7 per laser shot has been measured.

  16. Nuclear EGFRvIII resists hypoxic microenvironment induced apoptosis via recruiting ERK1/2 nuclear translocation

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Hui; Yang, Jinfeng; Xing, Wenjing; Dong, Yucui [Dept. of Immunology, Harbin Medical University, Harbin 150081 (China); Key Lab Infection & Immunity, Heilongjiang Province, Harbin 150081 (China); Ren, Huan, E-mail: renhuan@ems.hrbmu.edu.cn [Dept. of Immunology, Harbin Medical University, Harbin 150081 (China); Key Lab Infection & Immunity, Heilongjiang Province, Harbin 150081 (China)

    2016-02-05

    Glioblastoma (GBM) is the most aggressive type of primary brain tumor. Its interaction with the tumor microenvironment promotes tumor progression. Furthermore, GBM bearing expression of EGFRvIII displays more adaptation to tumor microenvironment related stress. But the mechanisms were poorly understood. Here, we presented evidence that in the human U87MG glioblastoma tumor model, EGFRvIII overexpression led aberrant kinase activation and nuclear translocation of EGFRvIII/ERK1/2 under hypoxia, which induced growth advantage by resisting apoptosis. Additionally, EGFRvIII defective in nuclear entry impaired this capacity in hypoxia adaptation, and partially interrupted ERK1/2 nuclear translocation. Pharmacology or genetic interference ERK1/2 decreased hypoxia resistance triggered by EGFRvIII expression, but not EGFRvIII nuclear translocation. In summary, this study identified a novel role for EGFRvIII in hypoxia tolerance, supporting an important link between hypoxia and subcellular localization alterations of the receptor. - Highlights: • Nuclear translocation of EGFRvIII contributes to GBM cell apoptotic resistance by hypoxia. • Nuclear ERK1/2 facilitates EGFRvIII in hypoxia resistance. • EGFRvIII nuclear translocation is not dependent on ERK1/2.

  17. A unified view of coherent and incoherent dihydrogen exchange in transition metal hydrides by nuclear resonance and inelastic neutron scattering

    Energy Technology Data Exchange (ETDEWEB)

    Limbach, H.H.; Ulrich, S.; Buntkowsky, G. [Freie Univ. Berlin (Germany). Inst. fuer Organische Chemie; Sabo-Etienne, S.; Chaudret, B. [Toulouse-3 Univ., 31 (France). Lab. de Chimie de Coordination du C.N.R.S.; Kubas, G.J.; Eckert, J. [Los Alamos National Lab., NM (United States)

    1995-08-12

    In this paper a unified view of coherent and incoherent dihydrogen exchange in transition metal hydrides by nuclear magnetic resonance (NMR) and inelastic neutron scattering (INS) is presented. It is shown that both exchange processes coexist i.e. do not transform into each other although they may dominate the spectra in different temperature ranges. This superposition is the consequence of the incorporation of the tunnel frequency J of the coherent process into the nuclear two-spin hamiltonian of hydrogen pairs which allows to treat the problem using the well known density matrix theory of NMR line-shapes developed by Alexander and Binsch. It is shown that this theory can also be used to predict the line-shapes of the rotational tunneling transitions observed in the INS spectra of transition metal dihydrogen complexes and that both NMR and INS spectra depend on similar parameters.

  18. Investigations of nuclear structure and nuclear reactions induced by complex projectiles

    Energy Technology Data Exchange (ETDEWEB)

    Sarantites, D.G.

    1990-01-01

    This report discusses research in the following areas: nuclear structure; fusion reactions near and below the barrier; incomplete fusion and fragmentation reactions; and instrumentation and analysis. (LSP).

  19. Multisectional linear ion trap and novel loading method for optical spectroscopy of electron and nuclear transitions.

    Science.gov (United States)

    Sysoev, Alexey A; Troyan, Victor I; Borisyuk, Peter V; Krasavin, Andrey V; Vasiliev, Oleg S; Palchikov, Vitaly G; Avdeev, Ivan A; Chernyshev, Denis M; Poteshin, Sergey S

    2015-01-01

    There is a growing need for the development of atomic and nuclear frequency standards because of the important contribution of methods for precision time and frequency measurements to the development of fundamental science, technology, and the economy. It is also conditioned by their potential use in optical clocks and quantum logic applications. It is especially important to develop a universal method that could allow one to use ions of most elements effectively (including ones that are not easily evaporated) proposed for the above-mentioned applications. A linear quadrupole ion trap for the optical spectroscopy of electron and nuclear transitions has been developed and evaluated experimentally. An ion source construction is based on an ultra-high vacuum evaporator in which a metal sample is subjected to an electron beam of energy up to 1 keV, resulting in the appearance of gaseous atoms and ions of various charge state. The linear ion trap consists of five successive quadrupole sections including an entrance quadrupole section, quadrupole mass filter, quadrupole ion guide, ion-trap section, and exit quadrupole section. The same radiofrequency but a different direct current voltage feeds the quadrupole sections. The instrument allows the mass and energy selected trapping of ions from ion beams of various intensities and their localization in the area of laser irradiation. The preliminary results presented show that the proposed instrument and methods allow one to produce effectively up to triply charged thorium ions as well as to trap ions for future spectroscopic study. The instrument is proposed for future use in optical clocks and quantum logic application development.

  20. Studies on magnetic-field-induced first-order transitions

    Indian Academy of Sciences (India)

    P Chaddah

    2006-07-01

    We shall discuss magnetization and transport measurements in materials exhibiting a broad first-order transition. The phase transitions would be caused by varying magnetic field as well as temperature, and we concentrate on ferro- to antiferromagnetic transitions in magnetic materials. We distinguish between metastable supercooled phases and metastable glassy phase.

  1. From Crisis to Transition: The State of Russian Science Based on Focus Groups with Nuclear Physicists

    Energy Technology Data Exchange (ETDEWEB)

    Gerber, T P; Ball, D Y

    2001-12-09

    can attract foreign investment and fuel renewed economic progress in Russia. Russian scientists could also be an important source of support for democratic norms: sociologists of science have long argued that scientists tend to support democracy because it provides them with the freedom in which their research can flourish. At the same time, a more recent study suggests that funding shortages may override the researcher's need for freedom and drive scientists to align themselves with the economic policies espoused by Nationalists and Communists in order to survive. Therefore, much turns on the question: ''What is the state of science in Russia today?'' The good news is that focus group interviews with Russian nuclear physicists conducted in October 2001 suggest that the ''science in crisis'' image is one-sided and misleading. Though scientists still complained about low salaries, lack of respect in society, and other similar issues, the participants in the focus groups also expressed positive sentiments about recent changes in the field of science. To be sure, the financing of science remains at a considerably lower level than during the heyday of Soviet times. Yet, it is now possible to earn a decent living as a scientist because of the greater availability of foreign and domestic grants and contracts. In addition, state funding has stabilized over the past few years. Thus, it is more accurate to say that Russian science is in a state of transition rather than in a state of crisis.

  2. Higher-order baryon number susceptibilities: Interplay between the chiral and the nuclear liquid-gas transitions

    Science.gov (United States)

    Mukherjee, A.; Steinheimer, J.; Schramm, S.

    2017-08-01

    We use an improved version of the SU(3) flavor parity-doublet quark-hadron model to investigate the higher-order baryon number susceptibilities near the chiral and the nuclear liquid-gas transitions. The parity-doublet model has been improved by adding higher-order interaction terms of the scalar fields in the effective mean field Lagrangian, resulting in a much-improved description of nuclear ground-state properties, in particular the nuclear compressibility. The resulting phase diagram of the model agrees qualitatively with expectations from lattice QCD, i.e., it shows a crossover at zero net baryochemical potential and a critical point at finite density. Using this model, we investigate the dependence of the higher-order baryon number susceptibilities as a function of temperature and chemical potential. We observe a strong interplay between the chiral and liquid-gas transition at intermediate baryochemical potentials. Due to this interplay between the chiral and the nuclear liquid-gas transitions, the experimentally measured cumulants of the net baryon number may show very different beam energy dependence, subject to the actual freeze-out temperature.

  3. Higher-order baryon number susceptibilities: interplay between the chiral and the nuclear liquid-gas transitions

    CERN Document Server

    Mukherjee, A; Schramm, S

    2016-01-01

    We use an improved version of the SU(3) flavour parity-doublet quark-hadron model to investigate the higher order baryon number susceptibilities near the chiral and the nuclear liquid-gas transitions. The parity-doublet model has been improved by adding higher-order interaction terms of the scalar fields in the effective mean field Lagrangian, resulting in a much-improved description of nuclear ground-state properties, in particular the nuclear compressibility. The resulting phase diagram of the model agrees qualitatively with expectations from lattice QCD, i.e., it shows a crossover at zero net baryo-chemical potential and a critical point at finite density. Using this model, we investigate the dependence of the higher-order baryon number susceptibilities as function of temperature and chemical potential. We observe a string interplay between the chiral and liquid-gas transition at intermediate baryo chemical potentials. Due to this interplay between the chiral and the nuclear liquid-gas transitions, the exp...

  4. Laser-induced solid-solid phase transition in As under pressure: a theoretical prediction

    Energy Technology Data Exchange (ETDEWEB)

    Zijlstra, Eeuwe S; Huntemann, Nils; Garcia, Martin E [Theoretische Physik, Universitaet Kassel, Heinrich-Plett-Strasse 40, 34132 Kassel (Germany)], E-mail: Zijlstra@physik.uni-kassel.de

    2008-03-15

    In arsenic, a pressure-induced solid-solid phase transition from the A7 into the simple cubic structure has been experimentally demonstrated (Beister et al 1990 Phys. Rev. B 41 5535). In this paper, we present calculations, which predict that this phase transition can also be induced by an ultrashort laser pulse in As under pressure. In addition, calculations for the pressure-induced phase transition are presented. Using density functional theory in the generalized gradient approximation, we found that the pressure-induced phase transition takes place at 26.3 GPa and is accompanied by a volume change {delta}V=0.5 a{sub 0}{sup 3} atom{sup -1}. The laser-induced phase transition is predicted for an applied pressure of 23.8 GPa and an absorbed laser energy of 2.8 mRy atom{sup -1}.

  5. Quantum to classical transition induced by gravitational time dilation

    Science.gov (United States)

    Sokolov, Boris; Vilja, Iiro; Maniscalco, Sabrina

    2017-07-01

    We study the loss of quantumness caused by time dilation [I. Pikovski, M. Zych, F. Costa, and Č. Brukner, Nat. Phys. 11, 668 (2015), 10.1038/nphys3366] for a Schrödinger cat state. We give a holistic view of the quantum to classical transition by comparing the dynamics of several nonclassicality indicators, such as the Wigner function interference fringe, the negativity of the Wigner function, the nonclassical depth, the Vogel criterion, and the Klyshko criterion. Our results show that only two of these indicators depend critically on the size of the cat, namely, on how macroscopic the superposition is. Finally we compare the gravitation-induced decoherence times to the typical decoherence times due to classical noise originating from the unavoidable statistical fluctuations in the characteristic parameters of the system [J. Trapani, M. Bina, S. Maniscalco, and M. G. A. Paris, Phys. Rev. A 91, 022113 (2015), 10.1103/PhysRevA.91.022113]. We show that the experimental observation of decoherence due to time dilation imposes severe limitations on the allowed levels of classical noise in the experiments.

  6. 3rd International Workshop on Desorption Induced by Electronic Transitions

    CERN Document Server

    Knotek, Michael

    1988-01-01

    These proceedings are the result of the third international workshop on Desorption Induced by Electronic Transitions, DIET III, which took place on Shelter Island, NY, May. 20-22, 1987. The work contained in this volume is an excellent summary of the current status of the field and should be a valuable reference text for both "seasoned" researchers and newcomers in the field of DIET. Based on the success of the meeting it seems clear that interest and enthusiasm in the field is strong. It is also apparent, from the many lively discussions during the meeting, that many unanswered questions (and controversies) remain to be solved. It was particularly pleasing to see many new participants from new and rapidly advancing fields, ranging from gas phase dynamics to semiconductor processing. The resulting cross-fertilization from these separate but related fields is playing an important role in helping us understand desorption processes at solid surfaces. In general, the topics covered during the course of the worksh...

  7. Induced phase transitions of nanoparticle-stabilized emulsions

    Science.gov (United States)

    Frijters, Stefan; Günther, Florian; Harting, Jens

    2013-11-01

    Nanoparticles can stabilize fluid-fluid interfaces over long timescales and are nowadays commonly used, e.g. in emulsions. However, their fundamental properties are as of yet poorly understood. Nanoparticle-stabilized emulsions can exhibit different phases, such as Pickering emulsions or bijels, which can be characterized by their different topologies and rheology. We investigate the effect of various initial conditions on random mixtures of two fluids and nanoparticles - in particular, the final state these systems will reach. For this, we use the well-established 3D lattice Boltzmann method, extended to allow for the added nanoparticles. After the evolution of the emulsions has stopped, we induce transitions from one state to another by gradually changing the wettability of the nanoparticles over time. This changes the preferential local curvature of the interfaces, which strongly affects the global state. We observe strong hysteresis effects because of the energy barrier presented by the necessary massive reordering of the particles. Being able to change emulsion states in situ has potential application possibilities in filtering technology, or creating particle scaffolds.

  8. Extensional Flow-Induced Dynamic Phase Transitions in Isotactic Polypropylene.

    Science.gov (United States)

    Ju, Jianzhu; Wang, Zhen; Su, Fengmei; Ji, Youxin; Yang, Haoran; Chang, Jiarui; Ali, Sarmad; Li, Xiangyang; Li, Liangbin

    2016-09-01

    With a combination of fast extension rheometer and in situ synchrotron radiation ultra-fast small- and wide-angle X-ray scattering, flow-induced crystallization (FIC) of isotactic polypropylene (iPP) is studied at temperatures below and above the melting point of α crystals (Tmα). A flow phase diagram of iPP is constructed in strain rate-temperature space, composing of melt, non-crystalline shish, α and α&β coexistence regions, based on which the kinetic and dynamic competitions among these four phases are discussed. Above Tmα , imposing strong flow reverses thermodynamic stabilities of the disordered melt and the ordered phases, leading to the occurrence of FIC of β and α crystals as a dynamic phase transition. Either increasing temperature or stain rate favors the competiveness of the metastable β over the stable α crystals, which is attributed to kinetic rate rather than thermodynamic stability. The violent competitions among four phases near the boundary of crystal-melt may frustrate crystallization and result in the non-crystalline shish winning out.

  9. Immunohistochemical localization of spermatid nuclear transition protein 2 in the testes of rats and mice.

    Science.gov (United States)

    Alfonso, P J; Kistler, W S

    1993-03-01

    Transition protein 2 (TP2) of the rat was isolated by differential precipitation with trichloroacetic acid, chromatography over Bio-Rex 70, and preparative gel electrophoresis. A polyclonal rabbit antiserum was raised that did not cross-react with unrelated acid-soluble proteins from liver or testes. The antiserum was used to identify TP2-related proteins obtained from testes of mice, hamsters, guinea pigs, rabbits, and boars by Western blotting. Immunohistochemical techniques were used to localize TP2 in paraffin-embedded testis sections from mice and rats. In both species, TP2 was first detected in spermatids that had essentially completed the morphological change from a round to an elongate nucleus and that were undergoing chromosomal condensation (spermatids of step 13 in rat and step 12 in mouse). TP2 was retained in spermatid nuclei until early step 16 in the rat and step 14 in the mouse. Serial sections of rat testis exposed separately to antisera to TP1 and TP2 showed that the great majority of labeled tubules were reactive to both antisera. However, in occasional tubules, TP1 reactivity was retained in relatively late spermatids that were negative for TP2. Thus both TP1 and TP2 appear in the nucleus essentially simultaneously, in association with the beginning of chromatin condensation and at a point well after much of the nuclear shaping has occurred.

  10. Enhanced spin-dependent parity-nonconservation effect in the 7 s 1/2 2S →6 d 5/2 2D transition in Fr: A possibility for unambiguous detection of the nuclear anapole moment

    Science.gov (United States)

    Sahoo, B. K.; Aoki, T.; Das, B. P.; Sakemi, Y.

    2016-03-01

    Employing the relativistic coupled-cluster method, comparative studies of the parity nonconserving electric dipole amplitudes for the 7 s 1/2 2S →6 d 5/2 2D transitions in 210Fr and 211Fr isotopes have been carried out. It is found that these transition amplitudes, sensitive only to the nuclear spin-dependent effects, are enhanced substantially owing to the very large contributions from the electron core-polarization effects in Fr. This translates to a relatively large and, in principle, measurable induced light shift, which would be a signature of nuclear spin-dependent parity nonconservation that is dominated by the nuclear anapole moment in a heavy atom like Fr. A plausible scheme to measure this quantity using the Cyclotron and Radioisotope Center (CYRIC) facility at Tohoku University has been outlined.

  11. Impact of the symmetry energy on nuclear pasta phases and crust-core transition in neutron stars

    CERN Document Server

    Bao, S S

    2015-01-01

    We study the impact of the symmetry energy on properties of nuclear pasta phases and crust-core transition in neutron stars. We perform a self-consistent Thomas--Fermi calculation employing the relativistic mean-field model. The properties of pasta phases presented in the inner crust of neutron stars are investigated and the crust-core transition is examined. It is found that the slope of the symmetry energy plays an important role in determining the pasta phase structure and the crust-core transition. The correlation between the symmetry energy slope and the crust-core transition density obtained in the Thomas--Fermi approximation is consistent with that predicted by the liquid-drop model.

  12. Chronic respiratory aeroallergen exposure in mice induces epithelial-mesenchymal transition in the large airways.

    Directory of Open Access Journals (Sweden)

    Jill R Johnson

    Full Text Available Chronic allergic asthma is characterized by Th2-polarized inflammation and leads to airway remodeling and fibrosis but the mechanisms involved are not clear. To determine whether epithelial-mesenchymal transition contributes to airway remodeling in asthma, we induced allergic airway inflammation in mice by intranasal administration of house dust mite (HDM extract for up to 15 consecutive weeks. We report that respiratory exposure to HDM led to significant airway inflammation and thickening of the smooth muscle layer in the wall of the large airways. Transforming growth factor beta-1 (TGF-β1 levels increased in mouse airways while epithelial cells lost expression of E-cadherin and occludin and gained expression of the mesenchymal proteins vimentin, alpha-smooth muscle actin (α-SMA and pro-collagen I. We also observed increased expression and nuclear translocation of Snail1, a transcriptional repressor of E-cadherin and a potent inducer of EMT, in the airway epithelial cells of HDM-exposed mice. Furthermore, fate-mapping studies revealed migration of airway epithelial cells into the sub-epithelial regions of the airway wall. These results show the contribution of EMT to airway remodeling in chronic asthma-like inflammation and suggest that Th2-polarized airway inflammation can trigger invasion of epithelial cells into the subepithelial regions of the airway wall where they contribute to fibrosis, demonstrating a previously unknown plasticity of the airway epithelium in allergic airway disease.

  13. Simultaneous subsecond hyperpolarization of the nuclear and electron spins of phosphorus in silicon by optical pumping of exciton transitions.

    Science.gov (United States)

    Yang, A; Steger, M; Sekiguchi, T; Thewalt, M L W; Ladd, T D; Itoh, K M; Riemann, H; Abrosimov, N V; Becker, P; Pohl, H-J

    2009-06-26

    We demonstrate a method which can hyperpolarize both the electron and nuclear spins of 31P donors in Si at low field, where both would be essentially unpolarized in equilibrium. It is based on the selective ionization of donors in a specific hyperfine state by optically pumping donor bound exciton hyperfine transitions, which can be spectrally resolved in 28Si. Electron and nuclear polarizations of 90% and 76%, respectively, are obtained in less than a second, providing an initialization mechanism for qubits based on these spins, and enabling further ESR and NMR studies on dilute 31P in 28Si.

  14. Anhydrous octyl-glucoside phase transition from lamellar to isotropic induced by electric and magnetic fields.

    Science.gov (United States)

    Hashim, Rauzah; Sugimura, Akihiko; Nguan, Hock-Seng; Rahman, Matiur; Zimmermann, Herbert

    2017-02-28

    A static deuterium nuclear magnetic resonance ((2)HNMR) technique (magnetic field, B = 7.05 T) was employed to monitor the thermotropic lamellar phase of the anhydrous 1:1 mixture sample of octyl-b-D-glucoside (βOG) and that of partially deuterium labelled at the alpha position on the chain, i.e.,βOG-d2 In the absence of an electric field, the (2)H NMR spectrum of the mixture gives a typical quadrupolar doublet representing the aligned lamellar phase. Upon heating to beyond the clearing temperature at 112 °C, this splitting converts to a single line expected for an isotropic phase. Simultaneous application of magnetic and electric fields (E = 0.4 MV/m) at 85 °C in the lamellar phase, whose direction was set to be parallel or perpendicular to the magnetic field, resulted in the change of the doublet into a single line and this recovers to the initial doublet with time for both experimental geometries. This implies E- and B-field-induced phase transitions from the lamellar to an isotropic phase and a recovery to the lamellar phase again with time. Moreover, these phase transformations are accompanied by a transient current. A similar observation was made in a computational study when an electric field was applied to a water cluster system. Increasing the field strength distorts the water cluster and weakens its hydrogen bonds leading to a structural breakdown beyond a threshold field-strength. Therefore, we suggest the observed field-induced transition is likely due to a structure change of the βOG lamellar assembly caused by the field effect and not due to Joule heating.

  15. Bifurcation of transition paths induced by coupled bistable systems

    Science.gov (United States)

    Tian, Chengzhe; Mitarai, Namiko

    2016-06-01

    We discuss the transition paths in a coupled bistable system consisting of interacting multiple identical bistable motifs. We propose a simple model of coupled bistable gene circuits as an example and show that its transition paths are bifurcating. We then derive a criterion to predict the bifurcation of transition paths in a generalized coupled bistable system. We confirm the validity of the theory for the example system by numerical simulation. We also demonstrate in the example system that, if the steady states of individual gene circuits are not changed by the coupling, the bifurcation pattern is not dependent on the number of gene circuits. We further show that the transition rate exponentially decreases with the number of gene circuits when the transition path does not bifurcate, while a bifurcation facilitates the transition by lowering the quasi-potential energy barrier.

  16. Effect of Magnetic Field on the Phase Transition from Nuclear Matter to Quark Matter during Proto-Neutron Star Evolution

    CERN Document Server

    Gupta, V K; Singh, S; Anand, J D; Gupta, Asha

    2002-01-01

    We have studied phase transition from hadron matter to quark matter in the presence of high magnetic fields incorporating the trapped electron neutrinos at finite temperatures. We have used the density dependent quark mass (DDQM) model for the quark phase while the hadron phase is treated in the frame-work of relativistic mean field theory. It is seen that the nuclear energy at phase transition decreases with both magnetic field and temperature. A brief discussion of the effect of magnetic field in supernova explosions and proto-neutron star evolution is given.

  17. Investigations of nuclear structure and nuclear reactions induced by complex projectiles

    Energy Technology Data Exchange (ETDEWEB)

    Sarantites, D.G.

    1991-01-01

    The research program of our group touches five areas of nuclear physics: (1) Nuclear structure studies at high spin; (2) Studies at the interface between structure and reactions; (3) Production and study of hot nuclei; (4) Incomplete fusion and fragmentation reactions; and (5) Development and use of novel techniques and instrumentation in the above areas of research. The papers from these areas are discussed in this report.

  18. Design of cationic graft copolymers as a potential inducer of B-Z transition.

    Science.gov (United States)

    Shimada, Naohiko; Kano, Arihiro; Maruyama, Atsushi

    2009-01-01

    Biological roles of transition from B form to Z form of DNA (B-Z transition) have recently received attention. The B-Z transition was also employed as driving machinery of a nano-mechanical DNA device. However, there are little reports of effective inducer of the B-Z transition. We previously reported that poly((L)-Lysine)-graft-dextran induces B-Z transition and grafted dextran plays an important role for the B-Z transition. In this report, we designed cationic graft copolymer as a potential inducer of B-Z transition. Series of the copolymers consisting of poly((L)-Lysine) backbone and abundant of dextran (Dex) or poly(ethylene glycol) (PEG) side chains were prepared. The B-Z transition of poly(dG-dC)/Poly(dG-dC) were observed in the presence of these copolymers. The copolymers having higher content of Dex or PEG effectively induced the B-Z transition compared to that having lower content. The result indicated that not only electrostatic interaction between DNA and the poly((L)-Lysine) backbone but also hydrophilic graft chains play a role for the B-Z transition. We speculated that Dex- or PEG-enriched environment is favorable for Z form.

  19. Nuclear translocation of jacob in hippocampal neurons after stimuli inducing long-term potentiation but not long-term depression.

    Directory of Open Access Journals (Sweden)

    Thomas Behnisch

    Full Text Available BACKGROUND: In recent years a number of potential synapto-nuclear protein messengers have been characterized that are thought to be involved in plasticity-related gene expression, and that have the capacity of importin- mediated and activity-dependent nuclear import. However, there is a surprising paucity of data showing the nuclear import of such proteins in cellular models of learning and memory. Only recently it was found that the transcription factor cyclic AMP response element binding protein 2 (CREB2 transits to the nucleus during long-term depression (LTD, but not during long-term potentiation (LTP of synaptic transmission in hippocampal primary neurons. Jacob is another messenger that couples NMDA-receptor-activity to nuclear gene expression. We therefore aimed to study whether Jacob accumulates in the nucleus in physiological relevant models of activity-dependent synaptic plasticity. METHODOLOGY/PRINCIPAL FINDINGS: We have analyzed the dynamics of Jacob's nuclear import following induction of NMDA-receptor dependent LTP or LTD at Schaffer collateral-CA1 synapses in rat hippocampal slices. Using time-lapse imaging of neurons expressing a Jacob-Green-Fluorescent-Protein we found that Jacob rapidly translocates from dendrites to the nucleus already during the tetanization period of LTP, but not after induction of LTD. Immunocytochemical stainings confirmed the nuclear accumulation of endogenous Jacob in comparison to apical dendrites after induction of LTP but not LTD. Complementary findings were obtained after induction of NMDA-receptor dependent chemical LTP and LTD in hippocampal primary neurons. However, in accordance with previous studies, high concentrations of NMDA and glycine as well as specific activation of extrasynaptic NMDA-receptors resembling pathological conditions induce an even more profound increase of nuclear Jacob levels. CONCLUSIONS/SIGNIFICANCE: Taken together, these findings suggest that the two major forms of NMDA

  20. Nuclear Translocation of Jacob in Hippocampal Neurons after Stimuli Inducing Long-Term Potentiation but Not Long-Term Depression

    Science.gov (United States)

    Behnisch, Thomas; YuanXiang, PingAn; Bethge, Philipp; Parvez, Suhel; Chen, Ying; Yu, Jin; Karpova, Anna; Frey, Julietta U.; Mikhaylova, Marina; Kreutz, Michael R.

    2011-01-01

    Background In recent years a number of potential synapto-nuclear protein messengers have been characterized that are thought to be involved in plasticity-related gene expression, and that have the capacity of importin- mediated and activity-dependent nuclear import. However, there is a surprising paucity of data showing the nuclear import of such proteins in cellular models of learning and memory. Only recently it was found that the transcription factor cyclic AMP response element binding protein 2 (CREB2) transits to the nucleus during long-term depression (LTD), but not during long-term potentiation (LTP) of synaptic transmission in hippocampal primary neurons. Jacob is another messenger that couples NMDA-receptor-activity to nuclear gene expression. We therefore aimed to study whether Jacob accumulates in the nucleus in physiological relevant models of activity-dependent synaptic plasticity. Methodology/Principal Findings We have analyzed the dynamics of Jacob's nuclear import following induction of NMDA-receptor dependent LTP or LTD at Schaffer collateral-CA1 synapses in rat hippocampal slices. Using time-lapse imaging of neurons expressing a Jacob-Green-Fluorescent-Protein we found that Jacob rapidly translocates from dendrites to the nucleus already during the tetanization period of LTP, but not after induction of LTD. Immunocytochemical stainings confirmed the nuclear accumulation of endogenous Jacob in comparison to apical dendrites after induction of LTP but not LTD. Complementary findings were obtained after induction of NMDA-receptor dependent chemical LTP and LTD in hippocampal primary neurons. However, in accordance with previous studies, high concentrations of NMDA and glycine as well as specific activation of extrasynaptic NMDA-receptors resembling pathological conditions induce an even more profound increase of nuclear Jacob levels. Conclusions/Significance Taken together, these findings suggest that the two major forms of NMDA-receptor dependent

  1. Heterogeneous world model and collaborative scenarios of transition to globally sustainable nuclear energy systems

    OpenAIRE

    2015-01-01

    The International Atomic Energy Agency's International Project on Innovative Nuclear Reactors and Fuel Cycles (INPRO) is to help ensure that nuclear energy is available to contribute to meeting global energy needs of the 21st century in a sustainable manner. The INPRO task titled “Global scenarios” is to develop global and regional nuclear energy scenarios that lead to a global vision of sustainable nuclear energy in the 21st century. Results of multiple studies show that the criteria for dev...

  2. Improved energy of the 21.5 keV M1 + E2 nuclear transition in {sup 151}Eu

    Energy Technology Data Exchange (ETDEWEB)

    Inoyatov, A.Kh. [JINR, Laboratory of Nuclear Problems, Dubna, Moscow Region (Russian Federation); National University, Institute of Applied Physics, Tashkent (Uzbekistan); Kovalik, A. [JINR, Laboratory of Nuclear Problems, Dubna, Moscow Region (Russian Federation); Nuclear Physics Institute of the ASCR, Rez near Prague (Czech Republic); Filosofov, D.V.; Perevoshchikov, L.L. [JINR, Laboratory of Nuclear Problems, Dubna, Moscow Region (Russian Federation); Rysavy, M. [Nuclear Physics Institute of the ASCR, Rez near Prague (Czech Republic); Baimukhanova, A. [JINR, Laboratory of Nuclear Problems, Dubna, Moscow Region (Russian Federation); Institute of Nuclear Physics, Almaty (Kazakhstan)

    2016-05-15

    Using internal conversion electron spectroscopy, improved energy 21 541.5±0.5 eV was determined for the 21.5 keV M1+E2 nuclear transition in {sup 151}Eu populated in the electron capture decay of {sup 151}Gd. This value was found to agree well with the present adopted value but is much more accurate. A value of 0.0305±0.0011 derived for the E2 admixture parameter vertical stroke δ(E2/M1) vertical stroke from the measured conversion electron line intensities corresponds to the present adopted value. A possible effect of nuclear structure on the multipolarity of the 21.5 keV transition was also investigated. (orig.)

  3. Isospin and symmetry energy effects on nuclear fragment production in liquid-gas type phase transition region

    CERN Document Server

    Buyukcizmeci, N; Botvina, A S

    2005-01-01

    We have demonstrated that the isospin of nuclei influences the fragment production during the nuclear liquid-gas phase transition. Calculations for Au197, Sn124, La124 and Kr78 at various excitation energies were carried out on the basis of the statistical multifragmentation model (SMM). We analyzed the behavior of the critical exponent tau with the excitation energy and its dependence on the critical temperature. Relative yields of fragments were classified with respect to the mass number of the fragments in the transition region. In this way, we have demonstrated that nuclear multifragmentation exhibits a 'bimodality' behavior. We have also shown that the symmetry energy has a small influence on fragment mass distribution, however, its effect is more pronounced in the isotope distributions of produced fragments.

  4. Isospin and symmetry energy effects on nuclear fragment distributions in liquid-gas type phase transition region

    CERN Document Server

    Buyukcizmeci, N; Botvina, A S

    2004-01-01

    We have demonstrated that the isospin of nuclei influences the fragment distributions during the nuclear liquid-gas phase transition. Calculations for Au197, Sn124, La124 and Kr78 at various excitation energies were carried out on the basis of the statistical multifragmentation model (SMM). We analyzed the behavior of the critical exponent tau with the excitation energy and its dependence on the critical temperature. Relative yields of fragments were classified with respect to the mass number of the fragments in the transition region. In this way, we have demonstrated that nuclear multifragmentation exhibits a 'bimodality' behavior. We have also shown that the symmetry energy has a small influence on fragment mass distribution, however, its effect is more pronounced in the isotope distributions of produced fragments.

  5. Nuclear Energy R&D Imperative 3: Enable a Transition Away from Fossil Fuel in the Transportation and Industrial Sectors

    Energy Technology Data Exchange (ETDEWEB)

    David Petti; J. Stephen Herring

    2010-03-01

    As described in the Department of Energy Office of Nuclear Energy’s Nuclear Energy R&D Roadmap, nuclear energy can play a significant role in supplying energy for a growing economy while reducing both our dependence on foreign energy supplies and emissions from the burning of fossil fuels. The industrial and transportation sectors are responsible for more than half of the greenhouse gas emissions in the U.S., and imported oil supplies 70% of the energy used in the transportation sector. It is therefore important to examine the various ways nuclear energy can facilitate a transition away from fossil fuels to secure environmentally sustainable production and use of energy in the transportation and manufacturing industry sectors. Imperative 3 of the Nuclear Energy R&D Roadmap, entitled “Enable a Transition Away from Fossil Fuels by Producing Process Heat for use in the Transportation and Industrial Sectors”, addresses this need. This document presents an Implementation Plan for R&D efforts related to this imperative. The expanded use of nuclear energy beyond the electrical grid will contribute significantly to overcoming the three inter-linked energy challenges facing U.S. industry: the rising and volatile prices for premium fossil fuels such as oil and natural gas, dependence on foreign sources for these fuels, and the risks of climate change resulting from carbon emissions. Nuclear energy could be used in the industrial and transportation sectors to: • Generate high temperature process heat and electricity to serve industrial needs including the production of chemical feedstocks for use in manufacturing premium fuels and fertilizer products, • Produce hydrogen for industrial processes and transportation fuels, and • Provide clean water for human consumption by desalination and promote wastewater treatment using low-grade nuclear heat as a useful additional benefit. Opening new avenues for nuclear energy will significantly enhance our nation’s energy

  6. Nuclear Energy R&D Imperative 3: Enable a Transition Away from Fossil Fuel in the Transportation and Industrial Sectors

    Energy Technology Data Exchange (ETDEWEB)

    David Petti; J. Stephen Herring

    2010-03-01

    As described in the Department of Energy Office of Nuclear Energy’s Nuclear Energy R&D Roadmap, nuclear energy can play a significant role in supplying energy for a growing economy while reducing both our dependence on foreign energy supplies and emissions from the burning of fossil fuels. The industrial and transportation sectors are responsible for more than half of the greenhouse gas emissions in the U.S., and imported oil supplies 70% of the energy used in the transportation sector. It is therefore important to examine the various ways nuclear energy can facilitate a transition away from fossil fuels to secure environmentally sustainable production and use of energy in the transportation and manufacturing industry sectors. Imperative 3 of the Nuclear Energy R&D Roadmap, entitled “Enable a Transition Away from Fossil Fuels by Producing Process Heat for use in the Transportation and Industrial Sectors”, addresses this need. This document presents an Implementation Plan for R&D efforts related to this imperative. The expanded use of nuclear energy beyond the electrical grid will contribute significantly to overcoming the three inter-linked energy challenges facing U.S. industry: the rising and volatile prices for premium fossil fuels such as oil and natural gas, dependence on foreign sources for these fuels, and the risks of climate change resulting from carbon emissions. Nuclear energy could be used in the industrial and transportation sectors to: • Generate high temperature process heat and electricity to serve industrial needs including the production of chemical feedstocks for use in manufacturing premium fuels and fertilizer products, • Produce hydrogen for industrial processes and transportation fuels, and • Provide clean water for human consumption by desalination and promote wastewater treatment using low-grade nuclear heat as a useful additional benefit. Opening new avenues for nuclear energy will significantly enhance our nation’s energy

  7. Dependence of nuclear quadrupole resonance transitions on the electric field gradient asymmetry parameter for nuclides with half-integer spins

    Science.gov (United States)

    Cho, Herman

    2016-09-01

    Allowed transition energies and eigenstate expansions have been calculated and tabulated in numerical form as functions of the electric field gradient asymmetry parameter for the zero field Hamiltonian of quadrupolar nuclides with I = 3 / 2 , 5 / 2 , 7 / 2, and 9 / 2. These results are essential to interpret nuclear quadrupole resonance (NQR) spectra and extract accurate values of the electric field gradient tensors. Applications of NQR methods to studies of electronic structure in heavy element systems are proposed.

  8. Roughness Induced Boundary Layer Transition in Incompressible Flow

    NARCIS (Netherlands)

    Ye, Q.; Schrijer, F.J.; Scarano, F.

    2015-01-01

    The fluid dynamics process leading to laminar-turbulent transition behind an isolated roughness element is investigated in the incompressible regime using particle image velocimetry. The study covers the effect of roughness size and geometry on the promotion of transition. The measurement domain cov

  9. Japanese suppliers in transition from domestic nuclear reactor vendors to international suppliers

    Energy Technology Data Exchange (ETDEWEB)

    Forsberg, C.W.; Reich, W.J.; Rowan, W.J.

    1994-06-27

    Japan is emerging as a major leader and exporter of nuclear power technology. In the 1990s, Japan has the largest and strongest nuclear power supply industry worldwide as a result of the largest domestic nuclear power plant construction program. The Japanese nuclear power supply industry has moved from dependence on foreign technology to developing, design, building, and operating its own power plants. This report describes the Japanese nuclear power supply industry and examines one supplier--the Mitsubishi group--to develop an understanding of the supply industry and its relationship to the utilities, government, and other organizations.

  10. Probing the nuclear symmetry energy with heavy-ion reactions induced by neutron-rich nuclei

    Institute of Scientific and Technical Information of China (English)

    CHEN Lie-wen; KO Che-Ming; LI Bao-an; YONG Gao-chan

    2007-01-01

    Heavy-ion reactions induced by neutron-rich nuclei provide a unique means to investigate the equation of state of isospin-asymmetric nuclear matter,especially the density dependence of the nuclear symmetry energy.In particular,recent analyses of the isospin diffusion data in heavyion reactions have already put a stringent constraint on thenuclear symmetry energy around the nuclear matter saturation density.We review this exciting result and discuss its implications on nuclear effective interactions and the neutron skin thickness of heavy nuclei.In addition,we also review the theoretical progress on probing the high density behaviors of the nuclear symmetry energy in heavy-ion reactions induced by high energy radioactive beams.

  11. Instantaneous nonvertical electronic transitions with shaped femtosecond laser pulses: Is it possible?

    DEFF Research Database (Denmark)

    Henriksen, Niels Engholm; Møller, Klaus Braagaard

    2003-01-01

    In molecular electronic transitions, a vertical transition can be induced by an ultrashort laser pulse. That is, a replica of the initial nuclear state-times the transition dipole moment of the electronic transition-can be created instantaneously (on the time scale of nuclear motion) in the excited...

  12. Fast phase transitions induced by picosecond electrical pulses on phase change memory cells

    Science.gov (United States)

    Wang, W. J.; Shi, L. P.; Zhao, R.; Lim, K. G.; Lee, H. K.; Chong, T. C.; Wu, Y. H.

    2008-07-01

    The reversible and fast phase transitions induced by picosecond electrical pulses are observed in the nanostructured GeSbTe materials, which provide opportunities in the application of high speed nonvolatile random access memory devices. The mechanisms for fast phase transition are discussed based on the investigation of the correlation between phase transition speed and material size. With the shrinkage of material dimensions, the size effects play increasingly important roles in enabling the ultrafast phase transition under electrical activation. The understanding of how the size effects contribute to the phase transition speed is of great importance for ultrafast phenomena and applications.

  13. Pulse laser induced graphite-to-diamond phase transition: the role of quantum electronic stress

    Science.gov (United States)

    Wang, ZhengFei; Liu, Feng

    2017-02-01

    First-principles calculations show that the pulse laser induced graphite-to-diamond phase transition is related to the lattice stress generated by the excited carriers, termed as "quantum electronic stress (QES)". We found that the excited carriers in graphite generate a large anisotropic QES that increases linearly with the increasing carrier density. Using the QES as a guiding parameter, structural relaxation spontaneously transforms the graphite phase into the diamond phase, as the QES is reduced and minimized. Our results suggest that the concept of QES can be generally applied as a good measure to characterize the pulse laser induced phase transitions, in analogy to pressure induced phase transitions.

  14. Measuring the Th-229 nuclear isomer transition with U-233 doped crystals

    CERN Document Server

    Stellmer, Simon; Kazakov, Georgy; Sterba, Johannes; Schumm, Thorsten

    2015-01-01

    We propose a simple approach to measure the energy of the few-eV isomeric state in Th-229. To this end, U-229 nuclei are doped into VUV-transparent crystals, where they undergo alpha decay into Th-229, and, with a probability of 2%, populate the isomeric state. These Th-229m nuclei may decay into the nuclear ground state under emission of the sought-after VUV gamma, whose wavelength can be determined with a spectrometer. Based on measurements of the optical transmission of U:CaF2 crystals in the VUV range, we expect a signal at least 2 orders of magnitude larger compared to current schemes using surface-implantation of recoil nuclei. The signal background is dominated by Cherenkov radiation induced by beta decays of the thorium decay chain. We estimate that, even if the isomer undergoes radiative de-excitation with a probability of only 0.1%, the VUV gamma can be detected within a reasonable measurement time.

  15. Heterogeneous world model and collaborative scenarios of transition to globally sustainable nuclear energy systems

    Directory of Open Access Journals (Sweden)

    Kuznetsov Vladimir

    2015-01-01

    Full Text Available The International Atomic Energy Agency's International Project on Innovative Nuclear Reactors and Fuel Cycles (INPRO is to help ensure that nuclear energy is available to contribute to meeting global energy needs of the 21st century in a sustainable manner. The INPRO task titled “Global scenarios” is to develop global and regional nuclear energy scenarios that lead to a global vision of sustainable nuclear energy in the 21st century. Results of multiple studies show that the criteria for developing sustainable nuclear energy cannot be met without innovations in reactor and nuclear fuel cycle technologies. Combining different reactor types and associated fuel chains creates a multiplicity of nuclear energy system arrangements potentially contributing to global sustainability of nuclear energy. In this, cooperation among countries having different policy regarding fuel cycle back end would be essential to bring sustainability benefits from innovations in technology to all interested users. INPRO has developed heterogeneous global model to capture countries’ different policies regarding the back end of the nuclear fuel cycle in regional and global scenarios of nuclear energy evolution and applied in a number of studies performed by participants of the project. This paper will highlight the model and major conclusions obtained in the studies.

  16. HDAC inhibitors induce epithelial-mesenchymal transition in colon carcinoma cells.

    Science.gov (United States)

    Ji, Meiying; Lee, Eun Jeoung; Kim, Ki Bae; Kim, Yangmi; Sung, Rohyun; Lee, Sang-Jeon; Kim, Don Soo; Park, Seon Mee

    2015-05-01

    The effects of histone deacetylase (HDAC) inhibitors on epithelial-mesenchymal transition (EMT) differ in various types of cancers. We investigated the EMT phenotype in four colon cancer cell lines when challenged with HDAC inhibitors trichostatin A (TSA) and valproic acid (VPA) with or without transforming growth factor-β1 (TGF-β1) treatment. Four colon cancer cell lines with different phenotypes in regards to tumorigenicity, microsatellite stability and DNA mutation were used. EMT phenotypes were assessed by the expression of E-cadherin and vimentin using western blot analysis, immunofluorescence, quantitative real-time RT-PCR following treatment with TSA (100 or 200 nM) or VPA (0.5 mM) with or without TGF-β1 (5 ng/ml) for 24 h. Biological EMT phenotypes were also evaluated by cell morphology, migration and invasion assays. TSA or VPA induced mesenchymal features in the colon carcinoma cells by a decrease in E-cadherin and an increase in vimentin expression at the mRNA and protein levels. Confocal microscopy revealed membranous attenuation or nuclear translocation of E-cadherin and enhanced expression of vimentin. These responses occurred after 6 h and increased until 24 h. Colon cancer cells changed from a round or rectangular shape to a spindle shape with increased migration and invasion ability following TSA or VPA treatment. The susceptibility to EMT changes induced by TSA or VPA was comparable in microsatellite stable (SW480 and HT29) and microsatellite unstable cells (DLD1 and HCT116). TSA or VPA induced a mesenchymal phenotype in the colon carcinoma cells and these effects were augmented in the presence of TGF-β1. HDAC inhibitors require careful caution before their application as new anticancer drugs for colon cancers.

  17. Pressure-induced Phase Transitions in Defect Pyrochlores

    Directory of Open Access Journals (Sweden)

    Claudio A. Perottoni

    2013-12-01

    Full Text Available In this paper the influence of pressure and temperature on four compounds with defect pyrochlore structure (NH4NbWO6, RbNbWO6, CsNbWO6 and p-WO3 is explored by means of X-ray diffraction, vibrational (Raman and infrared absorption spectroscopy and computer simulations. Several structural transitions were observed, including an unusual insertion reaction with volume increase at high pressures. This latter transition is further explored to reveal the influence on the transition pressure of the nature and ionic radius of the cation residing inside the cages formed by the pyrochlore framework.

  18. Wet Process Induced Phase Transited Drug Delivery System as a ...

    African Journals Online (AJOL)

    Nx 6110

    effect of varying osmotic pressure of the dissolution medium on drug release was studied. ... results of in vivo toxicity studies may support the use of phase transited ... ocular inflammatory conditions [16]. ... Flurbiprofen was obtained from Sun.

  19. Role of thermal heating on the voltage induced insulator-metal transition in VO2.

    Science.gov (United States)

    Zimmers, A; Aigouy, L; Mortier, M; Sharoni, A; Wang, Siming; West, K G; Ramirez, J G; Schuller, Ivan K

    2013-02-01

    We show that the main mechanism for the dc voltage or dc current induced insulator-metal transition in vanadium dioxide VO(2) is due to local Joule heating and not a purely electronic effect. This "tour de force" experiment was accomplished by using the fluorescence spectra of rare-earth doped micron sized particles as local temperature sensors. As the insulator-metal transition is induced by a dc voltage or dc current, the local temperature reaches the transition temperature indicating that Joule heating plays a predominant role. This has critical implications for the understanding of the dc voltage or dc current induced insulator-metal transition and has a direct impact on applications which use dc voltage or dc current to externally drive the transition.

  20. Crystal-Size-Dependent Structural Transitions in Nanoporous Crystals: Adsorption-Induced Transitions in ZIF-8

    KAUST Repository

    Zhang, Chen

    2014-09-04

    © 2014 American Chemical Society. Understanding the crystal-size dependence of both guest adsorption and structural transitions of nanoporous solids is crucial to the development of these materials. We find that nano-sized metal-organic framework (MOF) crystals have significantly different guest adsorption properties compared to the bulk material. A new methodology is developed to simulate the adsorption and transition behavior of entire MOF nanoparticles. Our simulations predict that the transition pressure significantly increases with decreasing particle size, in agreement with crystal-size-dependent experimental measurements of the N2-ZIF-8 system. We also propose a simple core-shell model to examine this effect on length scales that are inaccessible to simulations and again find good agreement with experiments. This study is the first to examine particle size effects on structural transitions in ZIFs and provides a thermodynamic framework for understanding the underlying mechanism.

  1. Nuclear Jacobi and Poincaré transitions at high spins and temperatures: Account of dynamic effects and large-amplitude motion

    Science.gov (United States)

    Mazurek, K.; Dudek, J.; Maj, A.; Rouvel, D.

    2015-03-01

    We present a theoretical analysis of the competition between the so-called nuclear Jacobi and Poincaré shape transitions as a function of spin at high temperatures. The latter condition implies the method of choice, a realistic version of the nuclear liquid drop model, here the Lublin-Strasbourg drop model. We address specifically the fact that the Jacobi and Poincaré shape transitions are accompanied by the flattening of the total nuclear energy landscape as a function of the relevant deformation parameters, which enforces large-amplitude oscillation modes that need to be taken into account. For that purpose we introduce an approximate form of the collective Schrödinger equation whose solutions are used to calculate the most probable deformations associated with the nuclear Jacobi and Poincaré transitions. We discuss selected aspects of the new description focusing on the critical-spin values for both types of these transitions.

  2. Electric Field-induced Conformational Transition of Bovine Serum Albumin from α -helix to β -sheet

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The irreversible conformational transition of bovine serum albumin (BSA) from α -helix to β -sheet, induced by electric field near the electrode surface, was monitored by circular dichroism (CD) with a long optical path thin layer cell (LOPTLC).

  3. Nature of unusual spontaneous and field-induced phase transitions in multiferroics RMn 2O 5

    Science.gov (United States)

    Pyatakov, A. P.; Kadomtseva, A. M.; Vorob'ev, G. P.; Popov, Yu. F.; Krotov, S. S.; Zvezdin, A. K.; Lukina, M. M.

    2009-04-01

    Complex magnetic, magnetoelectric and magnetoelastic studies of spontaneous and field-induced phase transitions in TmMn 2O 5 were carried out. In the vicinity of spontaneous phase transition temperatures (35 and 25 K) the magnetoelectric and magnetoelastic dependences demonstrated the jumps of polarization and magnetostriction induced by the field ˜150 kOe. These anomalies can be attributed to the influence of magnetic field on the conditions of incommensurate-commensurate phase transition at 35 K and the reverse one at 25 K. In b-axis dependences the magnetic field-induced spin-reorientation phase transition was also observed below 20 K. Finally the magnetoelectric anomaly associated with metamagnetic transition is observed below the temperature of rare-earth subsystem ordering at relatively small critical fields of 5 kOe. This variety of spontaneous and induced phase transitions in RMn 2O 5 stems from the interplay of three magnetic subsystems: Mn 3+, Mn 4+, R 3+. The comparison with YMn 2O 5 highlights the role of rare earth in low-temperature region (metamagnetic and spin-reorientation phase transitions), while the phase transition at higher temperatures between incommensurate and commensurate phases should be ascribed to the different temperature dependences of Mn 3+ and Mn 4+ ions. The strong correlation of magnetoelastic and magnetoelectric properties observed in the whole class of RMn 2O 5 highlights their multiferroic nature.

  4. Temperature and magnetic field induced multiple magnetic transitions in DyAg(2).

    Science.gov (United States)

    Arora, Parul; Chattopadhyay, M K; Sharath Chandra, L S; Sharma, V K; Roy, S B

    2011-02-09

    The magnetic properties of the rare-earth intermetallic compound DyAg(2) are studied in detail with the help of magnetization and heat capacity measurements. It is shown that the multiple magnetic phase transitions can be induced in DyAg(2) both by temperature and magnetic field. The detailed magnetic phase diagram of DyAg(2) is determined experimentally. It was already known that DyAg(2) undergoes an incommensurate to commensurate antiferromagnetic phase transition close to 10 K. The present experimental results highlight the first order nature of this phase transition, and show that this transition can be induced by magnetic field as well. It is further shown that another isothermal magnetic field induced transition or metamagnetic transition exhibited by DyAg(2) at still lower temperatures is also of first order nature. The multiple magnetic phase transitions in DyAg(2) give rise to large peaks in the temperature dependence of the heat capacity below 17 K, which indicates its potential as a magnetic regenerator material for cryocooler related applications. In addition it is found that because of the presence of the temperature and field induced magnetic phase transitions, and because of short range magnetic correlations deep inside the paramagnetic regime, DyAg(2) exhibits a fairly large magnetocaloric effect over a wide temperature window, e.g., between 10 and 60 K.

  5. AIRE-induced apoptosis is associated with nuclear translocation of stress sensor protein GAPDH

    Energy Technology Data Exchange (ETDEWEB)

    Liiv, Ingrid, E-mail: ingrid.liiv@ut.ee [Molecular Pathology, Institute of General and Molecular Pathology, University of Tartu, Tartu (Estonia); Haljasorg, Uku; Kisand, Kai; Maslovskaja, Julia; Laan, Martti; Peterson, Paert [Molecular Pathology, Institute of General and Molecular Pathology, University of Tartu, Tartu (Estonia)

    2012-06-22

    Highlights: Black-Right-Pointing-Pointer AIRE induces apoptosis in epithelial cells. Black-Right-Pointing-Pointer CARD domain of AIRE is sufficient for apoptosis induction. Black-Right-Pointing-Pointer AIRE induced apoptosis involves GAPDH translocation to the nuclei. Black-Right-Pointing-Pointer Deprenyl inhibits AIRE induced apoptosis. -- Abstract: AIRE (Autoimmune Regulator) has a central role in the transcriptional regulation of self-antigens in medullary thymic epithelial cells, which is necessary for negative selection of autoreactive T cells. Recent data have shown that AIRE can also induce apoptosis, which may be linked to cross-presentation of these self-antigens. Here we studied AIRE-induced apoptosis using AIRE over-expression in a thymic epithelial cell line as well as doxycycline-inducible HEK293 cells. We show that the HSR/CARD domain in AIRE together with a nuclear localization signal is sufficient to induce apoptosis. In the nuclei of AIRE-positive cells, we also found an increased accumulation of a glycolytic enzyme, glyceraldehyde-3-phosphate (GAPDH) reflecting cellular stress and apoptosis. Additionally, AIRE-induced apoptosis was inhibited with an anti-apoptotic agent deprenyl that blocks GAPDH nitrosylation and nuclear translocation. We propose that the AIRE-induced apoptosis pathway is associated with GAPDH nuclear translocation and induction of NO-induced cellular stress in AIRE-expressing cells.

  6. YB-1 overexpression promotes a TGF-β1-induced epithelial–mesenchymal transition via Akt activation

    Energy Technology Data Exchange (ETDEWEB)

    Ha, Bin; Lee, Eun Byul; Cui, Jun; Kim, Yosup [Department of Molecular Medicine, Lee Gil Ya Cancer and Diabetes Institute, Gachon University, Incheon 406-799 (Korea, Republic of); Jang, Ho Hee, E-mail: hhjang@gachon.ac.kr [Department of Molecular Medicine, Lee Gil Ya Cancer and Diabetes Institute, Gachon University, Incheon 406-799 (Korea, Republic of); Gachon Medical Research Institute, Gil Medical Center, Gachon University, Incheon (Korea, Republic of)

    2015-03-06

    The Y-box binding protein-1 (YB-1) is a transcription/translation regulatory protein, and the expression thereof is associated with cancer aggressiveness. In the present study, we explored the regulatory effects of YB-1 during the transforming growth factor-β1 (TGF-β1)-induced epithelial-to-mesenchymal transition (EMT) in lung adenocarcinoma cells. Downregulation of YB-1 increased E-cadherin promoter activity, and upregulation of YB-1 decreased promoter activity, suggesting that the YB-1 level may be correlated with the EMT. TGF-β1 induced YB-1 expression, and TGF-β1 translocated cytosolic YB-1 into the nucleus. YB-1 overexpression promoted TGF-β1-induced downregulation of epithelial markers, upregulation of mesenchymal markers, and cell migration. Moreover, YB-1 overexpression enhanced the expression of E-cadherin transcriptional repressors via TGF-β1-induced Akt activation. Our findings afford new insights into the role played by YB-1 in the TGF-β1 signaling pathway. - Highlights: • YB-1 regulates E-cadherin expression in A549 cells. • TGF-β1 induces upregulating and nuclear localization of YB-1. • YB-1 overexpression accelerates TGF-β1-induced EMT and cell migration. • YB-1 regulates Snail and Slug expression via Akt activation.

  7. Method for Predicting the Jet-Induced Aerodynamics for V/STOL Configurations in Transition.

    Science.gov (United States)

    1981-01-30

    transition flight regime is presented. This method is appli- cable to low-wing, circular jet subsonic VSTOL configurations -.,ich normall’r exhausting jets... power off, and p_ is the static pressure of the free stream fluid. Thus, the data represents the induced effects produced by the jet. As plotted in...TN D-7191, 1973. 6. Kuhn, R. E., An Empirical Method for Estimating the Jet-Induced Effects on V/STOL Configurations in Transition, Report No. R- AMPAC

  8. Pairing-induced speedup of nuclear spontaneous fission

    CERN Document Server

    Sadhukhan, Jhilam; Nazarewicz, W; Sheikh, J A; Baran, A

    2014-01-01

    Collective inertia is strongly influenced at the level crossing at which quantum system changes diabatically its microscopic configuration. Pairing correlations tend to make the large-amplitude nuclear collective motion more adiabatic by reducing the effect of those configuration changes. Competition between pairing and level crossing is thus expected to have a profound impact on spontaneous fission lifetimes. To elucidate the role of nucleonic pairing on spontaneous fission, we study the dynamic fission trajectories of $^{264}$Fm and $^{240}$Pu using the state-of-the-art self-consistent framework. We employ the superfluid nuclear density functional theory with the Skyrme energy density functional SkM$^*$ and a density-dependent pairing interaction. Along with shape variables, proton and neutron pairing correlations are taken as collective coordinates. The collective inertia tensor is calculated within the nonperturbative cranking approximation. The fission paths are obtained by using the least action princip...

  9. Nuclear fusion induced by X-rays in a crystal

    CERN Document Server

    Belyaev, V B; Otto, J; Rakityansky, S A

    2016-01-01

    The nuclei that constitute a crystalline lattice, oscillate relative to each other with a very low energy that is not sufficient to penetrate through the Coulomb barriers separating them. An additional energy, which is needed to tunnel through the barrier and fuse, can be supplied by external electromagnetic waves (X-rays or the synchrotron radiation). Exposing to the X-rays the solid compound LiD (lithium-deuteride) for the duration of 111 hours, we have detected 88 events of the nuclear fusion d+Li6 ---> Be8*. Our theoretical estimate agrees with what we observed. One of possible applications of the phenomenon we found, could be the measurements of the rates of various nuclear reactions (not necessarily fusion) at extremely low energies inaccessible in accelerator experiments.

  10. The transcription factor LEF-1 induces an epithelial–mesenchymal transition in MDCK cells independent of β-catenin

    Energy Technology Data Exchange (ETDEWEB)

    Kobayashi, Wakako; Ozawa, Masayuki, E-mail: mozawa@m.kufm.kagoshima-u.ac.jp

    2013-12-06

    Highlights: •The transcription factor LEF-1 induces an EMT in MDCK cells. •A mutant LEF-1 that cannot interact with β-catenin retained the ability. •The nuclear function of β-catenin was not necessary for the LEF-1-induced EMT. •The mRNA levels of Slug, ZEB1, and ZEB2 increased significantly in these cells. -- Abstract: The epithelial–mesenchymal transition (EMT), a key process in the tumor metastatic cascade, is characterized by the loss of cell–cell junctions and cell polarity, as well as the acquisition of migratory and invasive properties. LEF-1 is a member of the lymphoid enhancer-binding factor/T-cell factor (LEF/TCF) family of DNA-binding transcription factors, which interact with nuclear β-catenin and act as central transcriptional mediators of Wnt signaling. To investigate the role of LEF-1 in EMT, we generated stable LEF-1 transfectants using MDCK cells. The transfectants had a spindle-shaped mesenchymal morphology, and enhanced migration and invasiveness relative to control cells. These EMT changes were accompanied by the downregulation of an epithelial marker protein, E-cadherin, and the upregulation of mesenchymal marker proteins, vimentin and N-cadherin. Consistent with these observations, the mRNA levels of Slug, ZEB1, and ZEB2—EMT-related transcription factors—increased significantly. Although the N-terminally deleted mutant LEF-1 cannot interact with β-catenin, it retained the ability to induce EMT. Consistent with these observations, neither the expression of a dominant negative β-catenin/engrailed chimera, nor the expression of a cytoplasmic domain of E-cadherin that sequesters β-catenin from binding to LEF/TCF, reversed LEF-1-induced EMT. Together, these data indicated that the nuclear function of β-catenin was not necessary for the induction of Slug, ZEB1, and ZEB2 expression leading to EMT.

  11. Total Nuclear Reaction Cross Section Induced by Halo Nuclei and Stable Nuclei

    Institute of Scientific and Technical Information of China (English)

    GUO Wen-Jun; JIANG Huan-Qing; LIU Jian-Ye; ZUO Wei; REN Zhong-Zhou; LEE Xi-Guo

    2003-01-01

    We develop a method for calculation of the total reaction cross sections induced by the halo nuclei and stable. nuclei. This approach is based on the Glauber theory, which is valid for nuclear reactions at high energies. It is extended for nuclear reactions at low energies and intermediate energies by including both the quantum correction and Coulomb correction under the assumption of the effective nuclear density distribution. The calculated results of the total reaction cross section induced by stable nuclei agree well with 30 experimental data within 10 percent accuracy. The comparison between the numerical results and 20 experimental data for the total nuclear reaction cross section induced by the neutron halo nuclei and the proton halo nuclei indicates a satisfactory agreement after considering the halo structure of these nuclei, which implies quite different mean fields for the nuclear reactions induced by halo nuclei and stable nuclei. The halo nucleon distributions and the root-mean-square radii of these nuclei can be extracted from the above comparison based on the improved Glauber model, which indicates clearly the halo structures of these nuclei. Especially,it is clear to see that the medium correction of the nucleon-nucleon collision has little effect on the total reaction cross sections induced by the halo nuclei due to the very weak binding and the very extended density distribution.

  12. Total Nuclear Reaction Cross Section Induced by Halo Nuclei and Stable Nuclei

    Institute of Scientific and Technical Information of China (English)

    GUOWen-Jun; JIANGHuan-Qing; LIUJian-Ye; ZUOWei; RENZhong-Zhou; LEEXi-Guo

    2003-01-01

    We develop a method for calculation of the total reaction cross sections induced by the halo nuclei and stable nuclei. This approach is based on the Glauber theory, which is valid for nuclear reactions at high energies. It is extended for nuclear reactions at low energies and intermediate energies by including both the quantum correction and Coulomb correction under the assumption of the effective nuclear density distribution. The calculated results of the total reaction cross section induced by stable nuclei agree well with 30 experimental data within 10 percent accuracy.The comparison between the numerical results and 20 experimental data for the total nuclear reaction cross section induced by the neutron halo nuclei and the proton halo nuclei indicates a satisfactory agreement after considering the halo structure of these nuclei, which implies quite digerent mean fields for the nuclear reactions induced by halo nuclei and stable nuclei. The halo nucleon distributions and the root-mean-square radii of these nuclei can be extracted from the above comparison based on the improved Glauber model, which indicates clearly the halo structures of these nuclei. Especially,it is clear to see that the medium correction of the nucleon-nucleon collision has little effect on the total reaction cross sections, induced by the halo nuclei due to the very weak binding and the very extended density distribution.

  13. Effects of phase transition induced density fluctuations on pulsar dynamics

    Directory of Open Access Journals (Sweden)

    Partha Bagchi

    2015-07-01

    Full Text Available We show that density fluctuations during phase transitions in pulsar cores may have non-trivial effects on pulsar timings, and may also possibly account for glitches and anti-glitches. These density fluctuations invariably lead to non-zero off-diagonal components of the moment of inertia, leading to transient wobbling of star. Thus, accurate measurements of pulsar timing and intensity modulations (from wobbling may be used to identify the specific pattern of density fluctuations, hence the particular phase transition, occurring inside the pulsar core. Changes in quadrupole moment from rapidly evolving density fluctuations during the transition, with very short time scales, may provide a new source for gravitational waves.

  14. Acetylation dynamics of human nuclear proteins during the ionizing radiation-induced DNA damage response

    DEFF Research Database (Denmark)

    Bennetzen, Martin; Andersen, J.S.; Lasen, D.H.

    2013-01-01

    -dependent posttranslational modifications (PT Ms). To complement our previous analysis of IR-induced temporal dynamics of nuclear phosphoproteome, we now identify a range of human nuclear proteins that are dynamically regulated by acetylation, and predominantly deacetylation, during IR-induced DDR by using mass spectrometry......-based proteomic approaches. Apart from cataloging acetylation sites through SILAC proteomic analyses before IR and at 5 and 60 min after IR exposure of U2OS cells, we report that: (1) key components of the transcriptional machinery, such as EP 300 and CREBBP, are dynamically acetylated; (2) that nuclear...... to assess lysine acetylation status and thereby validate the mass spectrometry data. We thus present evidence that nuclear proteins, including those known to regulate cellular functions via epigenetic modifications of histones, are regulated by (de)acetylation in a timely manner upon cell's exposure...

  15. 原子核液-气相变的实验观察%Experimental Observables on Nuclear Liquid Gas Phase Transition

    Institute of Scientific and Technical Information of China (English)

    马余刚

    2007-01-01

    Progress on nuclear liquid gas phase transition (LGPT) or critical behavior has been simply reviewed and some signals of LGPT in heavy ion collisions, especially in NIMROD data, are focused. These signals include the power-law charge distribution, the largest fluctuation of the fragment observables, the nuclear Zipf law, caloric curve and critical exponent analysis etc.

  16. Pressure Induced Phase Transition in TiB

    Institute of Scientific and Technical Information of China (English)

    李凤英; 陈良辰; 王莉君; 顾惠成; 王汝菊; 车荣钲; 沈中毅

    2001-01-01

    In situ high pressure x-ray diffraction and electrical resistance experiments on TiB have been carried out by using a diamond anvil cell device. The results revealed that the sample undergoes a first-order phase transition at pressures of 3.5 - 5.0 Gpa and 4.0 - 5.5 Gpa for the x-ray diffraction and electrical resistance experiments, respectively. The parameters of the state equation are calculated before and after the phase transition and compared with the values calculated by Mohn et al. [J. Phys. C: Solid State Phys. 21(1988)2829] using the augmented spherical wave method.

  17. Noise-induced phase transitions in neuronal networks

    CERN Document Server

    Lee, K -E; Goltsev, A V

    2013-01-01

    Using an exactly solvable cortical model of a neuronal network, we show that, by increasing the intensity of shot noise (flow of random spikes bombarding neurons), the network undergoes first- and second-order non-equilibrium phase transitions. We study the nature of the transitions, bursts and avalanches of neuronal activity. Saddle-node and supercritical Hopf bifurcations are the mechanisms of emergence of sustained network oscillations. We show that the network stimulated by shot noise behaves similar to the Morris-Lecar model of a biological neuron stimulated by an applied current.

  18. Lithium Attenuates TGF-β1-Induced Fibroblasts to Myofibroblasts Transition in Bronchial Fibroblasts Derived from Asthmatic Patients

    Directory of Open Access Journals (Sweden)

    Marta Michalik

    2012-01-01

    Full Text Available Bronchial asthma is a chronic disorder accompanied by phenotypic transitions of bronchial epithelial cells, smooth muscle cells, and fibroblasts. Human bronchial fibroblasts (HBFs derived from patients with diagnosed asthma display predestination towards TGF-β-induced phenotypic switches. Since the interference between TGF-β and GSK-3β signaling contributes to pathophysiology of chronic lung diseases, we investigated the effect of lithium, a nonspecific GSK-3β inhibitor, on TGF-β1-induced fibroblast to myofibroblast transition (FMT in HBF and found that the inhibition of GSK-3β attenuates TGF-β1-induced FMT in HBF populations derived from asthmatic but not healthy donors. Cytoplasmically sequestrated β-catenin, abundant in TGF-β1/LiCl-stimulated asthmatic HBFs, most likely interacts with and inhibits the nuclear accumulation and signal transduction of Smad proteins. These data indicate that the specific cellular context determines FMT-related responses of HBFs to factors interfering with the TGF-β signaling pathway. They may also provide a mechanistic explanation for epidemiological data revealing coincidental remission of asthmatic syndromes and their recurrence upon the discontinuation of lithium therapy in certain psychiatric diseases.

  19. The effect of adolescent- and parent-induced family transitions in middle adolescence.

    Science.gov (United States)

    Fröjd, Sari; Marttunen, Mauri; Kaltiala-Heino, Riittakerttu

    2012-09-01

    In a longitudinal school-based survey of Finnish adolescents aged 15-16 years at baseline, we examined associations of parent-induced family transitions (parental separation, divorce, remarriage) and adolescent-induced family transitions (moving away from the parental home) with adolescent maladjustment (substance abuse and internalizing symptoms). The findings revealed that externalizing problems were associated with moving away from the parental home, whereas the risk of internalizing problems was associated with a change in the caretaking parent through parental marital transition or being taken into custody.

  20. Pressure induced phase transition in FeGa alloys

    Science.gov (United States)

    Devreugd, Christopher; Ahart, Muhtar; Gehring, Peter; Viehland, Dwight; Hemley, Russell

    2011-03-01

    Giant magnetostriction in Fe-- x Ga alloys (15 -- x - 27) offers potential for future generations of sensors and actuators. A maximum in the magnetostrictive strain is found at Ga content of about 19 percent, which is ten times higher than that of pure alpha-Fe. To investigate the behavior of FeGa alloys under pressure, we chose a slow cooled alloy of FeGa-19 as our sample and performed x-ray diffraction experiments in a diamond anvil cell up to 45 GPa. Diffraction pattern shows powder rings associated with (110), (200), and (211) Bragg reflections from expected bcc structure of iron below 24 GPa. We also observed the intensity increases along the powder rings associated with the crystal structure of Galfenol. Considering the (110) Bragg peak splits into three peaks above 24 GPa, our results indicate that FeGa alloy undergoes a bcc cubic to a hexagonal transition around 24 GPa. When the pressure is decreased, the hcp phase transforms back to the bcc phase. The transition mechanism can be understood by using the analogy to the bcc-hcp phase transition in pure iron under pressure. The transition in iron is a martensitic or displacive one. The hcp structure can be derived from the bcc structure through a relatively minor distortion of the bcc structure.

  1. Optically induced structural phase transitions in ion Coulomb crystals

    DEFF Research Database (Denmark)

    Horak, Peter; Dantan, Aurelien Romain; Drewsen, Michael

    2012-01-01

    , such as body-centered cubic and face-centered cubic, can be suppressed by a proper choice of the potential depth and periodicity. Furthermore, by varying the harmonic trap parameters and/or the optical potential in time, controlled transitions between crystal structures can be obtained with close to unit...

  2. Interleukin-2 induces tyrosine phosphorylation and nuclear translocation of stat3 in human T lymphocytes

    DEFF Research Database (Denmark)

    Nielsen, M; Svejgaard, A; Skov, S

    1994-01-01

    that stimulation through the IL-2R induced tyrosine phosphorylation and subsequent nuclear translocation of stat3, a newly identified member of the signal transducers and activators of transcription (STAT) family of proteins. In contrast, stat1 proteins were not tyrosine phosphorylated after IL-2 ligation, whereas...... an apparent molecular mass of 84 kDa and was not recognized by stat3 or stat1 mAb or antisera. Since IL-2 induced nuclear translocation of the 84 kDa protein and stat3 followed identical kinetics, p84 is a candidate for a new, yet undefined, member of the STAT family. Taken together, we report that IL-2...... induces tyrosine phosphorylation and subsequent nuclear translocation of stat3 and an as yet undefined 84-kDa protein in antigen-specific human T cell lines....

  3. Relaxation-allowed nuclear magnetic resonance transitions by interference between the quadrupolar coupling and the paramagnetic interaction.

    Science.gov (United States)

    Ling, Wen; Jerschow, Alexej

    2007-02-14

    Of the various ways in which nuclear spin systems can relax to their ground states, the processes involving an interference between different relaxation mechanisms, such as dipole-dipole coupling and chemical shift anisotropy, have become of great interest lately. The authors show here that the interference between the quadrupolar coupling and the paramagnetic interaction (cross-correlated relaxation) gives rise to nuclear spin transitions that would remain forbidden otherwise. In addition, frequency shifts arise. These would be reminiscent of residual anisotropic interactions when there are none. While interesting from a fundamental point of view, these processes may become relevant in magnetic resonance imaging experiments which involve quadrupolar spins, such as (23)Na, in the presence of contrast agents. Geometrical constraints in paramagnetic molecule structures may likewise be derived from these interference effects.

  4. Nanosecond pulsed electric field induced cytoskeleton, nuclear membrane and telomere damage adversely impact cell survival.

    Science.gov (United States)

    Stacey, M; Fox, P; Buescher, S; Kolb, J

    2011-10-01

    We investigated the effects of nanosecond pulsed electric fields (nsPEF) on three human cell lines and demonstrated cell shrinkage, breakdown of the cytoskeleton, nuclear membrane and chromosomal telomere damage. There was a differential response between cell types coinciding with cell survival. Jurkat cells showed cytoskeleton, nuclear membrane and telomere damage that severely impacted cell survival compared to two adherent cell lines. Interestingly, disruption of the actin cytoskeleton in adherent cells prior to nsPEF exposure significantly reduced cell survival. We conclude that nsPEF applications are able to induce damage to the cytoskeleton and nuclear membrane. Telomere sequences, regions that tether and stabilize DNA to the nuclear membrane, are severely compromised as measured by a pan-telomere probe. Internal pore formation following nsPEF applications has been described as a factor in induced cell death. Here we suggest that nsPEF induced physical changes to the cell in addition to pore formation need to be considered as an alternative method of cell death. We suggest nsPEF electrochemical induced depolymerization of actin filaments may account for cytoskeleton and nuclear membrane anomalies leading to sensitization.

  5. Role of isospin in nuclear-matter liquid-gas phase transition; Role de l'isospin dans la transition de phase liquide-gaz de la matiere nucleaire

    Energy Technology Data Exchange (ETDEWEB)

    Ducoin, C

    2006-10-15

    Nuclear matter presents a phase transition of the liquid-gas type. This well-known feature is due to the nuclear interaction profile (mean-range attractive, short-range repulsive). Symmetric-nuclear-matter thermodynamics is thus analogous to that of a Van der Waals fluid. The study shows up to be more complex in the case of asymmetric matter, composed of neutrons and protons in an arbitrary proportion. Isospin, which distinguishes both constituents, gives a measure of this proportion. Studying asymmetric matter, isospin is an additional degree of freedom, which means one more dimension to consider in the space of observables. The nuclear liquid-gas transition is associated with the multi-fragmentation phenomenon observed in heavy-ion collisions, and to compact-star physics: the involved systems are neutron rich, so they are affected by the isospin degree of freedom. The present work is a theoretical study of isospin effects which appear in the asymmetric nuclear matter liquid-gas phase transition. A mean-field approach is used, with a Skyrme nuclear effective interaction. We demonstrate the presence of a first-order phase transition for asymmetric matter, and study the isospin distillation phenomenon associated with this transition. The case of phase separation at thermodynamic equilibrium is compared to spinodal decomposition. Finite size effects are addressed, as well as the influence of the electron gas which is present in the astrophysical context. (author)

  6. Transposon-induced nuclear mutations that alter chloroplast gene expression

    Energy Technology Data Exchange (ETDEWEB)

    Barkan, A.

    1992-01-01

    The goal of this project is to use mutant phenotypes as a guide to nuclear genes that determine the timing and localization of chloroplast development The immediate goals are to identify nuclear mutants with defects in chloroplast gene expression from maize lines harboring active Mu transposons; characterize their phenotypes to determine the precise defect in gene expression; clone several of the most interesting mutations by exploiting the transposon tag; and use the clones to further define the roles of these genes in modulating chloroplast gene expression. Three mutants were described earlier that had global defects in chloroplast gene expression. We have found that two of these mutations are allelic. Both alleles have global defects in chloroplast translation initiation, as revealed by the failure to assemble chloroplast mRNAs into polysomes. We have isolated and characterized three new mutants from Mu lines that have novel defects in chloroplast RNA metabolism. We are now ready to begin the task of cloning several of these genes, by using the Mu transposon tag.

  7. Chemically induced transition phenomena in polyurethanes as seen from generalized mode Grueneisen parameters

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, U; Philipp, M; Bactavatchalou, R; Sanctuary, R; Baller, J; Zielinski, B; Krueger, J K [Laboratoire de Physique des Materiaux, Universite du Luxembourg, 162A, Avenue de la Faiencerie, L-1115 (Luxembourg); Possart, W; Alnot, P [Laboratoire Europeen de Recherche, Universitaire Saarland-Lorraine (Luxembourg)], E-mail: ulrich.mueller@uni.lu

    2008-05-21

    Many phenomenological properties of reactive polymers like polyurethanes increase or decrease continuously in the course of the curing process before saturating at the end of the chemical reaction. This holds true for instance for the mass density, the refractive index, the chemical turnover and the hypersonic properties. The reason for this monotone behaviour is that the chemical reaction behaves like a continuous succession of irreversible phase transitions. These transitions are superposed by the sol-gel transition and possibly by the chemically induced glass transition, with the drawback that the latter two highlighted transitions are often hidden by the underlying curing process. In this work we propose generalized mode Grueneisen parameters as an alternative probe for elucidating the polymerization process itself and the closely related transition phenomena. As a model system we use polyurethane composed of a diisocyanate and varying ratios of difunctional and trifunctional alcohols.

  8. Dependence of nuclear quadrupole resonance transitions on the electric field gradient asymmetry parameter for nuclides with half-integer spins

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Herman

    2016-09-01

    Allowed transition energies and eigenstate expansions have been calculated and tabulated in numerical form as functions of the electric field gradient asymmetry parameter for the zero field Hamiltonian of quadrupolar nuclides with I = 3/2, 5/2, 7/2, and 9/2. These results may be used to interpret nuclear quadrupole resonance (NQR) spectra and extract accurate values of the electric field gradient tensors. Applications of NQR methods to studies of electronic structure in heavy element systems are proposed. This material is based upon work supported by the U.S. Department of Energy Office of Science, Office of Basic Energy Sciences, Heavy Element Chemistry program.

  9. Redox Chemistry in Radiation Induced Dissolution of Spent Nuclear Fuel : from Elementary Reactions to Predictive Modeling

    OpenAIRE

    Roth, Olivia

    2008-01-01

    The focus of this doctoral thesis is the redox chemistry involved in radiation induced oxidative dissolution of spent nuclear fuel and UO2 (as a model substance for spent nuclear fuel). It is shown that two electron oxidants are more efficient than one electron oxidants in oxidative dissolution of UO2 at low oxidant concentrations. Furthermore, it is shown that H2O2 is the only oxidant that has to be taken into account in radiation induced dissolution of UO2 under deep repository conditions (...

  10. Optically induced phase transition of excitons in coupled quantum dots

    Institute of Scientific and Technical Information of China (English)

    Chen Zi-Dong

    2008-01-01

    The weak classical light excitations in many semiconductor quantum dots have been chosen as important solidstate quantum systems for processing quantum information and implementing quantum computing. For strong classical light we predict theoretically a novel phase transition as a function of magnitude of this classical light from the deformed to the normal phases in resonance case, and the essential features of criticality such as the scaling behaviour, critical exponent and universality are also present in this paper.

  11. Coupling and noise induced spiking-bursting transition in a parabolic bursting model.

    Science.gov (United States)

    Ji, Lin; Zhang, Jia; Lang, Xiufeng; Zhang, Xiuhui

    2013-03-01

    The transition from tonic spiking to bursting is an important dynamic process that carry physiologically relevant information. In this work, coupling and noise induced spiking-bursting transition is investigated in a parabolic bursting model with specific discussion on their cooperation effects. Fast/slow analysis shows that weak coupling may help to induce the bursting by changing the geometric property of the fast subsystem so that the original unstable periodical solution are stabilized. It turned out that noise can play the similar stabilization role and induce bursting at appropriate moderate intensity. However, their cooperation may either strengthen or weaken the overall effect depending on the choice of noise level.

  12. Nuclear Jacobi and Poincar\\'e Transitions at High Spins and Temperatures: Account~of~Dynamic~Effects~and~Large-Amplitude Motion

    CERN Document Server

    Mazurek, K; Maj, A; Rouvel, D

    2013-01-01

    We present a theoretical analysis of the competition between so-called nuclear Jacobi and Poincar\\'e shape transitions in function of spin - at high temperatures. The latter condition implies the method of choice - a realistic version of the nuclear Liquid Drop Model (LDM), here: the Lublin-Strasbourg Drop (LSD) model. We address specifically the fact that the Jacobi and Poincar\\'e shape transitions are accompanied by the flattening of total nuclear energy landscape as function of the relevant deformation parameters what enforces large amplitude oscillation modes that need to be taken into account. For that purpose we introduce an approximate form of the collective Schr\\"odinger equation whose solutions are used to calculate the most probable deformations associated with both types of transitions and discuss the physical consequences in terms of the associated critical-spin values and transitions themselves.

  13. Mangiferin induces apoptosis in multiple myeloma cell lines by suppressing the activation of nuclear factor kappa B-inducing kinase.

    Science.gov (United States)

    Takeda, Tomoya; Tsubaki, Masanobu; Kino, Toshiki; Yamagishi, Misa; Iida, Megumi; Itoh, Tatsuki; Imano, Motohiro; Tanabe, Genzoh; Muraoka, Osamu; Satou, Takao; Nishida, Shozo

    2016-05-05

    Mangiferin is a naturally occurring glucosyl xanthone, which induces apoptosis in various cancer cells. However, the molecular mechanism underlying mangiferin-induced apoptosis has not been clarified thus far. Therefore, we examined the molecular mechanism underlying mangiferin-induced apoptosis in multiple myeloma (MM) cell lines. We found that mangiferin decreased the viability of MM cell lines in a concentration-dependent manner. We also observed an increased number of apoptotic cells, caspase-3 activation, and a decrease in the mitochondrial membrane potential. In addition, mangiferin inhibited the nuclear translocation of nuclear factor kappa B (NF-κB) and expression of phosphorylated inhibitor kappa B (IκB) and increased the expression of IκB protein, whereas no changes were observed in the phosphorylation levels of extracellular signal-regulated kinase 1/2 (ERK1/2), c-Jun N-terminal protein kinase 1/2 (JNK1/2), and mammalian target of rapamycin (mTOR). The molecular mechanism responsible for mangiferin-induced inhibition of nuclear translocation of NF-κB was a decrease in the expression of phosphorylated NF-κB-inducing kinase (NIK). Moreover, mangiferin decreased the expression of X-linked inhibitor of apoptosis protein (XIAP), survivin, and Bcl-xL proteins. Knockdown of NIK expression showed results similar to those observed with mangiferin treatment. Our results suggest that mangiferin induces apoptosis through the inhibition of nuclear translocation of NF-κB by suppressing NIK activation in MM cell lines. Our results provide a new insight into the molecular mechanism of mangiferin-induced apoptosis. Importantly, since the number of reported NIK inhibitors is limited, mangiferin, which targets NIK, may be a potential anticancer agent for the treatment of MM.

  14. Optical Emission of the Nuclear-Induced Plasmas of Gas Mixtures

    Directory of Open Access Journals (Sweden)

    Mendykhan U. Khasenov

    2014-01-01

    Full Text Available The characteristic properties of the inverted-population-forming processes in lasers with ionizing pumping are considered. Results obtained from research of active laser media concerning the p-s transitions of atoms of neon, mercury, and cadmium are presented. The feasibility of ion-ion recombination in lasers with nuclear pumping is discussed. The excitation kinetics of the first negative system of CO, heteronuclear ionic molecules of inert gases, and halogenides of inert gases under ionizing radiation are considered.

  15. AIRE-induced apoptosis is associated with nuclear translocation of stress sensor protein GAPDH.

    Science.gov (United States)

    Liiv, Ingrid; Haljasorg, Uku; Kisand, Kai; Maslovskaja, Julia; Laan, Martti; Peterson, Pärt

    2012-06-22

    AIRE (Autoimmune Regulator) has a central role in the transcriptional regulation of self-antigens in medullary thymic epithelial cells, which is necessary for negative selection of autoreactive T cells. Recent data have shown that AIRE can also induce apoptosis, which may be linked to cross-presentation of these self-antigens. Here we studied AIRE-induced apoptosis using AIRE over-expression in a thymic epithelial cell line as well as doxycycline-inducible HEK293 cells. We show that the HSR/CARD domain in AIRE together with a nuclear localization signal is sufficient to induce apoptosis. In the nuclei of AIRE-positive cells, we also found an increased accumulation of a glycolytic enzyme, glyceraldehyde-3-phosphate (GAPDH) reflecting cellular stress and apoptosis. Additionally, AIRE-induced apoptosis was inhibited with an anti-apoptotic agent deprenyl that blocks GAPDH nitrosylation and nuclear translocation. We propose that the AIRE-induced apoptosis pathway is associated with GAPDH nuclear translocation and induction of NO-induced cellular stress in AIRE-expressing cells. Copyright © 2012 Elsevier Inc. All rights reserved.

  16. Pressure-induced phase transitions of indium selenide

    Science.gov (United States)

    Rasmussen, Anya Marie

    In2Se3 has potential as a phase-change material for memory applications. Understanding its phase diagram is important to achieve controlled switching between phases. Pressure-dependent phase transitions of In2Se3 bulk powders and nanowire samples were studied at room temperature and at elevated temperatures using synchrotron x-ray diffraction and diamond-anvil cells (DACs). alpha-In2Se3 transforms into the beta phase at 0.7 GPa, an order of magnitude lower than phase-transition critical pressures in typical semiconductors. The bulk moduli are reported and the c/a ratio for the beta phase is shown to have a highly nonlinear dependence on pressure. gamma-In2Se3, metastable under ambient conditions, transforms into to the high-pressure beta phase between 2.8 GPa and 3.2 GPa in bulk powder samples and at slightly higher pressures, between 3.2 GPa and 3.7 GPa in nanowire samples. While the gamma phase bulk modulus is similar to that of the beta phase, the decrease due to pressure in the unit cell parameter ratio, c/a, is less than half the decrease seen in the beta phase. Using high-temperature DACs, we investigated how elevated temperatures and pressures affect the crystal structure of In 2Se3. From these measurements, the high-pressure beta phase was found to be metastable. The high-pressure beta phase transitions into the high-temperature beta phase at temperatures above 380 °C.

  17. Non-congruence of liquid-gas phase transition of asymmetric nuclear matter

    CERN Document Server

    Maruyama, Toshiki

    2012-01-01

    We first explore the liquid-gas mixed phase in a bulk calculation, where two phases coexist without the geometrical structures. In the case of symmetric nuclear matter, the system behaves congruently, and the Maxwell construction becomes relevant. For asymmetric nuclear matter, on the other hand, the phase equilibrium is no more attained by the Maxwell construction since the liquid and gas phases are non-congruent; the particle fractions become completely different with each other. One of the origins of such non-congruence is attributed to the large symmetry energy. Subsequently we explore the charge-neutral nuclear matter with electrons by fully applying the Gibbs conditions to figure out the geometrical (pasta) structures in the liquid-gas mixed phase. We emphasize the effects of the surface tension and the Coulomb interaction on the pasta structures. We also discuss the thermal effects on the pasta structures.

  18. From cloned frogs to patient matched stem cells: induced pluripotency or somatic cell nuclear transfer?

    Science.gov (United States)

    Yamada, Mitsutoshi; Byrne, James; Egli, Dieter

    2015-10-01

    Nuclear transfer has seen a remarkable comeback in the past few years. Three groups have independently reported the derivation of stem cell lines by somatic cell nuclear transfer, from either adult, neonatal or fetal cells. Though the ability of human oocytes to reprogram somatic cells to stem cells had long been anticipated, success did not arrive on a straightforward path. Little was known about human oocyte biology, and nuclear transfer protocols developed in animals required key changes to become effective with human eggs. By overcoming these challenges, human nuclear transfer research has contributed to a greater understanding of oocyte biology, provided a point of reference for the comparison of induced pluripotent stem cells, and delivered a method for the generation of personalized stem cells with therapeutic potential.

  19. Mechanisms for pressure-induced crystal-crystal transition, amorphization, and devitrification of SnI{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Liu, H.; Tse, J. S., E-mail: john.tse@usask.ca [Department of Physics and Engineering Physics, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5B2 (Canada); Hu, M. Y.; Bi, W.; Zhao, J.; Alp, E. E. [Advanced Photon Source, Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, Illinois 60439 (United States); Pasternak, M. [School of Physics and Astronomy, Tel Aviv University, Ramat Aviv (Israel); Taylor, R. D.; Lashley, J. C. [Los Alamos National Laboratory, PO Box 1663 Bikini Atoll Road, Los Alamos, New Mexico 87545 (United States)

    2015-10-28

    The pressure-induced amorphization and subsequent recrystallization of SnI{sub 4} have been investigated using first principles molecular dynamics calculations together with high-pressure {sup 119}Sn nuclear resonant inelastic x-ray scattering measurements. Above ∼8 GPa, we observe a transformation from an ambient crystalline phase to an intermediate crystal structure and a subsequent recrystallization into a cubic phase at ∼64 GPa. The crystalline-to-amorphous transition was identified on the basis of elastic compatibility criteria. The measured tin vibrational density of states shows large amplitude librations of SnI{sub 4} under ambient conditions. Although high pressure structures of SnI{sub 4} were thought to be determined by random packing of equal-sized spheres, we detected electron charge transfer in each phase. This charge transfer results in a crystal structure packing determined by larger than expected iodine atoms.

  20. Beta-elemene blocks epithelial-mesenchymal transition in human breast cancer cell line MCF-7 through Smad3-mediated down-regulation of nuclear transcription factors.

    Directory of Open Access Journals (Sweden)

    Xian Zhang

    Full Text Available Epithelial-mesenchymal transition (EMT is the first step required for breast cancer to initiate metastasis. However, the potential of drugs to block and reverse the EMT process are not well explored. In the present study, we investigated the inhibitory effect of beta-elemene (ELE, an active component of a natural plant-derived anti-neoplastic agent in an established EMT model mediated by transforming growth factor-beta1 (TGF-β1. We found that ELE (40 µg/ml blocked the TGF-β1-induced phenotypic transition in the human breast cancer cell line MCF-7. ELE was able to inhibit TGF-β1-mediated upregulation of mRNA and protein expression of nuclear transcription factors (SNAI1, SNAI2, TWIST and SIP1, potentially through decreasing the expression and phosphorylation of Smad3, a central protein mediating the TGF-β1 signalling pathway. These findings suggest a potential therapeutic benefit of ELE in treating basal-like breast cancer.

  1. Pressure-induced phase transitions in L-alanine, revisited.

    Science.gov (United States)

    Tumanov, N A; Boldyreva, E V; Kolesov, B A; Kurnosov, A V; Quesada Cabrera, R

    2010-08-01

    The effect of pressure on L-alanine has been studied by X-ray powder diffraction (up to 12.3 GPa), single-crystal X-ray diffraction, Raman spectroscopy and optical microscopy (up to approximately 6 GPa). No structural phase transitions have been observed. At approximately 2 GPa the cell parameters a and b become accidentally equal to each other, but without a change in space-group symmetry. Neither of two transitions reported by others (to a tetragonal phase at approximately 2 GPa and to a monoclinic phase at approximately 9 GPa) was observed. The changes in cell parameters were continuous up to the highest measured pressures and the cells remained orthorhombic. Some important changes in the intermolecular interactions occur, which also manifest themselves in the Raman spectra. Two new orthorhombic phases could be crystallized from a MeOH/EtOH/H(2)O pressure-transmitting mixture in the pressure range 0.8-4.7 GPa, but only if the sample was kept at these pressures for at least 1-2 d. The new phases converted back to L-alanine on decompression. Judging from the Raman spectra and cell parameters, the new phases are most probably not L-alanine but its solvates.

  2. Electrically induced phase transition in GeSbTe alloys

    Energy Technology Data Exchange (ETDEWEB)

    Bruns, Gunnar; Schlockermann, Carl; Woda, Michael; Wuttig, Matthias [I. Physikalisches Institut Ia, RWTH Aachen, 52056 Aachen (Germany)

    2008-07-01

    While phase change materials have already successfully been applied in rewriteable optical data storage, they are now also promising to form the basis for novel non-volatile electrical data storage devices. To understand the physical concepts of these so-called Phase Change Random Access Memory (PCRAM) it is mandatory to gain a deeper insight into the switching process between the highly resistive amorphous and the lowly resistive crystalline phase. The fast phase transitions between the amorphous and crystalline state of GeSbTe-based alloys has so far often been studied using pulsed laser irradiation. In this work an alternative approach is employed to investigate this transition. Electrical pulses are used to rapidly and reversibly switch between the two states. For these experiments a setup was built with a specially designed contacting circuit board to meet the requirements of electrical measurements on a nanosecond timescale. The influence of the pulse parameters on the change of device resistance was determined for different initial states. Furthermore the high time resolution of 0.4 ns allows investigation of transient electrical effects like the so-called threshold switching first described by Ovshinsky in the late 1960s.

  3. Dynamic effects induced transition of droplets on biomimetic superhydrophobic surfaces.

    Science.gov (United States)

    Jung, Yong Chae; Bhushan, Bharat

    2009-08-18

    Superhydrophobic surfaces have considerable technological potential for various applications because of their extreme water-repellent properties. Dynamic effects, such as the bouncing and vibration of a droplet, can destroy the composite solid-air-liquid interface. The impact pressure of a bouncing droplet and the inertia force of a vibrating droplet affect the transition from a solid-air-liquid interface to a solid-liquid interface. Therefore, it is necessary to study the dynamic effect of droplets under various system parameters (impact velocity and frequency and amplitude of vibration). A new model for the prediction of the wetting and dewetting process during droplet vibration based on the relationship between the adhesion force and the inertia force of a droplet is proposed. To investigate whether micro-, nano-, and hierarchical structures can resist the destabilizing factors responsible for the transition, a study of bouncing and vibration of a water droplet is systematically conducted on various surfaces. The physics of wetting phenomena for water droplet studies is of fundamental importance in the geometrical design of superhydrophobic surfaces.

  4. Rhodamine B induces long nucleoplasmic bridges and other nuclear anomalies in Allium cepa root tip cells.

    Science.gov (United States)

    Tan, Dehong; Bai, Bing; Jiang, Donghua; Shi, Lin; Cheng, Shunchang; Tao, Dongbing; Ji, Shujuan

    2014-03-01

    The cytogenetic toxicity of rhodamine B on root tip cells of Allium cepa was investigated. A. cepa were cultured in water (negative control), 10 ppm methyl methanesulfonate (positive control), and three concentrations of rhodamine B (200, 100, and 50 ppm) for 7 days. Rhodamine B inhibited mitotic activity; increased nuclear anomalies, including micronuclei, nuclear buds, and bridged nuclei; and induced oxidative stress in A. cepa root tissues. Furthermore, a substantial amount of long nucleoplasmic bridges were entangled together, and some nuclei were simultaneously linked to several other nuclei and to nuclear buds with nucleoplasmic bridges in rhodamine B-treated cells. In conclusion, rhodamine B induced cytogenetic effects in A. cepa root tip cells, which suggests that the A. cepa root is an ideal model system for detecting cellular interactions.

  5. Nuclear-Spin-Induced Circular Dichroism in the Infrared Region for Liquids.

    Science.gov (United States)

    Chen, Fang; Yao, Guo-hua; Zhang, Zhen-lin; Liu, Fan-chen; Chen, Dong-ming

    2015-06-22

    Recently, the nuclear-spin-induced optical rotation (NSOR) and circular dichroism (NSCD) for liquids were discovered and extensively studied and developed. However, so far, nuclear-spin-induced magnetic circular dichroism in the IR region (IR-NSCD) has not been explored, even though all polyatomic molecules exhibit extensive IR spectra. Herein, IR-NSCD is proposed and discussed theoretically. The results indicate that in favorable conditions the IR-NSCD angle may be much larger than the NSOR angle in the UV/Vis region due to a vibrational resonance effect and can be measurable by using the NSOR experiment scheme. IR-NSCD can automatically combine and give NMR spectra and IRCD spectra of the nuclear spin prepolarized samples in liquids, which, in principle, could be developed to become a unique, novel analytical tool. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Hyperfine-induced electric dipole contributions to the electric octupole and magnetic quadrupole atomic clock transitions

    CERN Document Server

    Dzuba, V A

    2016-01-01

    Hyperfine-induced electric dipole contributions may significantly increase probabilities of otherwise very weak electric octupole and magnetic quadrupole atomic clock transitions (e.g. transitions between $s$ and $f$ electron orbitals). These transitions can be used for exceptionally accurate atomic clocks, quantum information processing and search for dark matter. They are very sensitive to new physics beyond the Standard Model, such as temporal variation of the fine structure constant, the Lorentz invariance and Einstein equivalence principle violation. We formulate conditions under which the hyperfine-induced electric dipole contribution dominates. Due to the hyperfine quenching the electric octupole clock transition in $^{173}$Yb$^+$ is two orders of magnitude stronger than that in currently used $^{171}$Yb$^+$. Some enhancement is found in $^{143}$Nd$^{13+}$, $^{149}$Pm$^{14+}$, $^{147}$Sm$^{14+}$, and $^{147}$Sm$^{15+}$ ions.

  7. Pressure-induced Phase Transition in Oleic Acid Studied by Raman Spectroscopy

    Science.gov (United States)

    Fan, Ya; Zhou, Jing; Li, Shuang; Guan, Fu-Ying; Xu, Da-Peng

    2011-11-01

    High-pressure Raman studies up to 0.84 GPa are performed on oleic acid. Spectral analysis indicates that oleic acid undergoes a pressure-induced phase transition in the 0.29-0.36 GPa range. Only one high-pressure phase below 0.84 GPa is present, in which the polymethylene chains take the ordered all-trans conformation, with the methyl end of the chains exhibiting the ordered tt chain-end conformation and the olefin group taking the skew-cis-skew' conformation. The conformational characters of the oleic acid molecule show that the high-pressure phase is the same as the low-temperature crystalline γ phase. The pressure-induced phase transition is typical of first-order transitions and the transition path during compression is different from that during cooling.

  8. Ferro-deformation and shape phase transitions over the nuclear chart: 50 < protons (Z) < 82 and 50 < neutrons (N) < 126

    CERN Document Server

    Moon, Chang-Bum

    2016-01-01

    We study a global nuclear structure in the framework of experimental observables. With the aid of large nuclear structure data at the national nuclear data center, NNDC, we present the distinctive systematic patterns emerged in the first 2+ excited energies, E(2+) and their energy ratios to the first 4+ levels, R = E(4+)/E(2+), in the even-even nuclei, over 50 < Z < 82 for protons, and 50 < N < 126 for neutrons. We introduce the so-called pseudo-shell configurations from the subshells mixture in order to explain a semi-double shell closure, a shape phase transition, and a reinforced deformation. It is found that the reinforced deformation arises when Z = 64 or 66 correlates with N = 90 and reaches its maximum, indicating R = 3.3. Such a saturated reinforced deformation spans over Z = 58 to 72 and N = 100 to 106 as showing its center at Z = 64 or 66 and at N = 102 or 104. We define this reinforced deformation 'a ferro-deformation' like a ferro-magnetism in condensed matter physics. The shape coexis...

  9. Experimental studies of keV energy neutron-induced reactions relevant to astrophysics and nuclear physics

    Energy Technology Data Exchange (ETDEWEB)

    Shima, T.; Kii, T.; Kikuchi, T.; Okazaki, F.; Kobayashi, T.; Baba, T.; Nagai, Y. [Tokyo Inst. of Tech. (Japan). Faculty of Science; Igashira, M.

    1997-03-01

    Nuclear reactions induced by keV energy neutrons provide a plenty of informations for studies of both astrophysics and nuclear physics. In this paper we will show our experimental studies of neutron- induced reactions of light nuclei in the keV energy region by means of a pulsed keV neutron beam and high-sensitivity detectors. Also we will discuss astrophysical and nuclear-physical consequences by using the obtained results. (author)

  10. Noise-Induced Phase Transition in Traffic Flow

    Institute of Scientific and Technical Information of China (English)

    LI Ke-Ping; GAO Zi-You

    2004-01-01

    One of the dynamic phases of the traffic flow is the traffic jam. It appears in traffic flow when the vehicledensity is larger than the critical value. In this paper, a new method is presented to investigate the traffic jam when thevehicle density is smaller than the critical value. In our method, we introduce noise into the traffic system after sufficienttransient time. Under the effect of noise, the traffic jam appears, and the phase transition from tree to synchronized flowoccurs in traffic flow. Our method is tested for the deterministic NaSch traffic model. The simulation results demonstratethat there exist a broad range of lower densities at which the noise effect leading to traffic jam can be observed.

  11. Noise-Induced Phase Transition in Traffic Flow

    Institute of Scientific and Technical Information of China (English)

    LIKe-Ping; GAOZi-You

    2004-01-01

    One of the dynamic phases of the traffic flow is the traffic jam. It appears in traffic flow when the vehicle density is larger than the critical value. In this paper, a new method is presented to investigate the traffic jam when the vehicle density is smaller than the critical value. In our method, we introduce noise into the traffic system after sufficient transient time. Under the effect of noise, the traffic jam appears, and the phase transition from free to synchronized flow occurs in traffic flow. Our method is tested for the deterministic NaSch traffic model. The simulation results demonstrate that there exist a broad range of lower densities at which the noise effect leading to traffic jam can be observed.

  12. Induced Institutional Transition of Contract Farming in Shandong Province

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    This article describes the process of institutional transition of contract farming in Shandong Province. The changes in preparatory stage of contract farming express in: One, the information asymmetry of the two sides of the contract is reducing; Two, the security system of contract farming tends to be perfection; Three, the organizational form of contract farming tends to be simplification. The measures taken in production stage of agricultural product are as follows: The first is investment in means of production; The second is perfection of field management; The third is soundness of quality test. The measures taken in purchase stage of agricultural product are as follows: First, product is developing from preliminary working to intensive processing; Second, leading enterprises develop to large-scale and standard. The changes in profit distribution stage of contract farming are as follows: First, the profit relationship between enterprises and peasant households turns from opposition to mutual benefit. Second, the means of default issues turn from emotional self-discipline to rational self-discipline. Performance of contract farming is analyzed: First is putting forward the transformation of agricultural operational form; Second is reducing the uncertainty; Third is truly realizing the risk sharing and participation of interest. The defect of institutional transition of contract farming is discussed: First is no longer the operational form that benefits many farmers; Second is still the typically incomplete contract; Third is expansion of capability gap of business game between leading enterprises and farmers; Fourth is the still existence of information asymmetry; Fifth is informal institution falling behind formal institutional arrangement. The corresponding countermeasures are put forward: First is developing professional cooperation; Second is completing land circulation system; Third is constructing honest information system; Fourth is building social

  13. Pressure-induced phase transition in silicon nitride material

    Institute of Scientific and Technical Information of China (English)

    Chen Dong; Yu Ben-Hai

    2013-01-01

    The equilibrium crystal structures,lattice parameters,elastic constants,and elastic moduli of the polymorphs α-,β-,and γ-Si3N4,have been calculated by first-principles method.β-Si3N4 is ductile in nature and has an ionic bonding.γ-Si3N4 is found to be a brittle material and has covalent chemical bonds,especially at high pressures.The phase boundary of the β → γ transition is obtained and a positive slope is found.This indicates that at higher temperatures it requires higher pressures to synthesize γ-Si3N4.On the other hand,the α → γ phase boundary can be described as P =14.37198 + 3.27 × 10-3T-7.83911 × 10-7T2-3.13552 × 10-10T3.The phase transition from α-to γ-Si3N4 occurs at 16.1 GPa and 1700 K.Then,the dependencies of bulk modulus,heat capacity,and thermal expansion on the pressure P are obtained in the ranges of 0 GPa-30 GPa and 0 K-2000 K.Significant features in these properties are observed at high temperatures.It turns out that the thermal expansion of γ-Si3N4 is larger than that of α-Si3N4 over wide pressure and temperature ranges.The evolutions of the heat capacity with temperature for the Si3N4 polymorphs are close to each other,which are important for possible applications of Si3N4.

  14. Boundary field induced first-order transition in the 2D Ising model: exact study

    Energy Technology Data Exchange (ETDEWEB)

    Clusel, Maxime [Institut Laue-Langevin, 6 rue Horowitz BP156 X, 38042 Grenoble Cedex (France); Fortin, Jean-Yves [Laboratoire Poncelet, 119002, Bolshoy Vlasyevskiy Pereulok 11, Moscow (Russian Federation)

    2006-02-03

    We present in this paper an exact study of a first-order transition induced by an inhomogeneous boundary magnetic field in the 2D Ising model. From a previous analysis of the interfacial free energy in the discrete case (Clusel and Fortin 2005 J. Phys. A: Math. Gen. 38 2849) we identify, using an asymptotic expansion in the thermodynamic limit, the line of transition that separates the regime where the interface is localized near the boundary from the one where it is propagating inside the bulk. In particular, the transition line has a strong dependence on the aspect ratio of the lattice.

  15. Z(5): critical point symmetry for the prolate to oblate nuclear shape phase transition

    Energy Technology Data Exchange (ETDEWEB)

    Bonatsos, Dennis; Lenis, D.; Petrellis, D.; Terziev, P.A

    2004-05-27

    A critical point symmetry for the prolate to oblate shape phase transition is introduced, starting from the Bohr Hamiltonian and approximately separating variables for {gamma}=30 deg. Parameter-free (up to overall scale factors) predictions for spectra and B(E2) transition rates are found to be in good agreement with experimental data for {sup 194}Pt, which is supposed to be located very close to the prolate to oblate critical point, as well as for its neighbours ({sup 192}Pt, {sup 196}Pt)

  16. Z(5): Critical point symmetry for the prolate to oblate nuclear shape phase transition

    CERN Document Server

    Bonatsos, D; Petrellis, D; Terziev, P A; Bonatsos, Dennis

    2004-01-01

    A critical point symmetry for the prolate to oblate shape phase transition is introduced, starting from the Bohr Hamiltonian and approximately separating variables for $\\gamma=30^{\\rm o}$. Parameter-free (up to overall scale factors) predictions for spectra and B(E2) transition rates are found to be in good agreement with experimental data for 194-Pt, which is supposed to be located very close to the prolate to oblate critical point, as well as for its neighbours (192-Pt, 196-Pt).

  17. Model of EF4-induced ribosomal state transitions and mRNA translocation

    Science.gov (United States)

    Xie, Ping

    2014-08-01

    EF4, a highly conserved protein present in bacteria, mitochondria and chloroplasts, can bind to both the posttranslocation and pretranslocation ribosomal complexes. When binding to the posttranslocation state, it catalyzes backward translocation to a pretranslocation state. When binding to the pretranslocation state, it catalyzes transition to another pretranslocation state that is similar and possibly identical to that resulting from the posttranslocation state bound by EF4, and competes with EF-G to regulate the elongation cycle. However, the molecular mechanism on how EF4 induces state transitions and mRNA translocation remains unclear. Here, we present both the model for state transitions induced by EF4 binding to the posttranslocation state and that by EF4 binding to the pretranslocation state, based on which we study the kinetics of EF4-induced state transitions and mRNA translocation, giving quantitative explanations of the available experimental data. Moreover, we present some predicted results on state transitions and mRNA translocation induced by EF4 binding to the pretranslocation state complexed with the mRNA containing a duplex region.

  18. Phase transitions and anionic dynamics of dimethylammonium hexachlorotellurate(IV) as studied by pulsed nuclear quadrupole resonance of chlorine

    Science.gov (United States)

    Ishikawa, Atsushi; Horiuchi, Keizo; Ikeda, Ryuichi; Nakamura, Daiyu

    1989-01-01

    The temperature dependence of 35Cl NQR frequencies has been reinvestigated for dimethylammonium hexachlorotellurate(IV) using an FT NQR spectrometer. A new line is observed just above the lowest-frequency line already reported for the intermediate-temperature phase. In the lowest-temperature phase, the temperature dependence is definitely determined by finding new lines. The NQR frequencies can be precisely measured even in the vicinity of the phase transitions. The temperature dependence of the nuclear quadrupole relaxation time, T1Q of 35Cl and 37Cl nuclei has also been observed. In a temperature range 64-160 K, the isotope ratio, T1Q( 37Cl)/ T1Q( 35Cl) is 1.5 for each line, suggesting that the quadrupolar relaxation arises mainly from the libration of the complex anion. Above 160 K, T1Q decreases very rapidly with increasing temperature for each line. This can be interpreted in terms of the onset of the reorientation of the anion as a whole, which is responsible for the fade-out phenomenon of the two lines occurring near 220 K. The nature of the phase transitions and the anionic dynamics are discussed in detail. Especially, the phase transition at 96 K which is rather unusual and is explained through softening of the librations and the rotational displacement of the anions successively operated.

  19. Influence of irradiation-induced disorder on the Peierls transition in TTF-TCNQ microdomains

    DEFF Research Database (Denmark)

    Solovyeva, Vita; Cmyrev, A.; Sachser, R.

    2011-01-01

    domains. The dependence of the resistivity on temperature follows a variable-range hopping behaviour which shows a crossover of the exponents as the Peierls transition is approached. The low temperature behaviour is analysed within the segmented rod model of Fogler, Teber and Shklovskii which...... was developed for charge-ordered quasi one-dimensional electron crystals (Fogler et al 2004 Phys. Rev. B 69 035413). The effect of substrate-induced biaxial strain on the Peierls transition temperature is discussed with regard to its interplay with the defect-induced changes....

  20. Pressure-induced phase transition of 1-butyl-3-methylimidazolium hexafluorophosphate [bmim][PF6

    Science.gov (United States)

    Takekiyo, Takahiro; Hatano, Naohiro; Imai, Yusuke; Abe, Hiroshi; Yoshimura, Yukihiro

    2011-03-01

    We have investigated the pressure-induced Raman spectral change of 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]) using Raman spectroscopy. The relative Raman intensity at 590 cm-1 of the CH2 rocking band assigned to the gauche conformer of the NCCC dihedral angle of the butyl group in the [bmim]+ cation increases when the pressure-induced liquid-crystalline phase transition occurs, while that at 610 cm-1 assigned to the trans conformer decreases. Our results show that the high-pressure phase transition of [bmim][PF6] causes the increase of the gauche conformer of the [bmim]+ cation.

  1. Altered expression of nuclear matrix proteins in etoposide induced apoptosis in HL-60 cells

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The events of cell death and the expression of nuclear matrix protein(NMP)have been investigated in a promyelocytic leukemic cell line HL-60 induced with etoposide.By means of TUNEL assay,the nuclei displayed a characteristic morphology change,and the amount of apoptotic cells increased early and reached maximun about 39% after treatment with etoposide for 2 h.Nucleosomal DNA fragmentation was observed after treatment for 4 h.The morphological change of HL-60 cells,thus,occurred earlier than the appearance of DNA ladder.Total nuclear matrix proteins were analyzed by 2-dimensional gel electrophoresis.Differential expression of 59 nuclear matrix proteins was found in 4 h etoposide treated cells.Western blotting was then performed on three nuclear matrix acssociated proteins,PML,HSC70 and NuMA.The expression of the suppressor PML protein and heat shock protein HSC70 were significantly upregulated after etoposide treatment,while NuMA,a nuclear mitotic apparatus protein,was down regulated.These results demonstrate that significant biochemical alterations in nuclear matrix proteins take place during the apoptotic process.

  2. Role of apoptosis-inducing factor (AIF in programmed nuclear death during conjugation in Tetrahymena thermophila

    Directory of Open Access Journals (Sweden)

    Endoh Hiroshi

    2010-02-01

    Full Text Available Abstract Background Programmed nuclear death (PND, which is also referred to as nuclear apoptosis, is a remarkable process that occurs in ciliates during sexual reproduction (conjugation. In Tetrahymena thermophila, when the new macronucleus differentiates, the parental macronucleus is selectively eliminated from the cytoplasm of the progeny, concomitant with apoptotic nuclear events. However, the molecular mechanisms underlying these events are not well understood. The parental macronucleus is engulfed by a large autophagosome, which contains numerous mitochondria that have lost their membrane potential. In animals, mitochondrial depolarization precedes apoptotic cell death, which involves DNA fragmentation and subsequent nuclear degradation. Results We focused on the role of mitochondrial apoptosis-inducing factor (AIF during PND in Tetrahymena. The disruption of AIF delays the normal progression of PND, specifically, nuclear condensation and kilobase-size DNA fragmentation. AIF is localized in Tetrahymena mitochondria and is released into the macronucleus prior to nuclear condensation. In addition, AIF associates and co-operates with the mitochondrial DNase to facilitate the degradation of kilobase-size DNA, which is followed by oligonucleosome-size DNA laddering. Conclusions Our results suggest that Tetrahymena AIF plays an important role in the degradation of DNA at an early stage of PND, which supports the notion that the mitochondrion-initiated apoptotic DNA degradation pathway is widely conserved among eukaryotes.

  3. Tension induced phase transitions in biomimetic fluid membranes

    Science.gov (United States)

    Shapiro, Marc; Vlahovska, Petia

    2012-11-01

    Membranes in eukaryotic cells are mixtures of hundreds of lipid species. The lipid diversity enables membranes to phase separate and form domains, called rafts, which play a critical role in cell functions such as signaling and trafficking. The phase transitions underlying raft formation have been extensively studied as a function of temperature and composition. However, the third dimension of the phase diagram, i.e., the tension (2D pressure), is still unexplored because membrane tension is difficult to control and quantify. To overcome this challenge, we develop two approaches, capillary micromechanics and electrodeformation, in which the tension is regulated by the area dilation accompanying deformation of a vesicle (a closed membrane). The first technique consists of forcing an initially quasi-spherical vesicle through a tapered glass microcapillary, while the second method utilizes uniform electric fields to deform the vesicle into an ellipsoid. Domains are visualized using a fluorescent dye, which preferentially partitions in one of the phases. The experimental results suggest that the miscibility temperature (at which domains form in an initially homogeneous membrane) increases with applied tension. Domain motions and coarsening are also investigated.

  4. A magnetically induced quantum phase transition in holography

    CERN Document Server

    Gnecchi, A; Papadoulaki, O; Toldo, C

    2016-01-01

    We investigate quantum phase transitions in a 2+1 dimensional gauge theory at finite chemical potential $\\chi$ and magnetic field $B$. The gravity dual is based on 4D $\\mathcal{N}=2$ Fayet-Iliopoulos gauged supergravity and the solutions we consider---that are constructed analytically---are extremal, dyonic, asymptotically $AdS_4$ black-branes with a nontrivial radial profile for the scalar field. We discover a line of second order fixed points at $B=B_c(\\chi)$ between the dyonic black brane and an extremal "thermal gas" solution with a singularity of good-type, according to the acceptability criteria of Gubser [1]. The dual field theory is the ABJM theory [2] deformed by a triple trace operator $\\Phi^3$ and placed at finite charge and magnetic field. This line of fixed points might be useful in studying the various strongly interacting quantum critical phenomena such as the ones proposed to underlie the cuprate superconductors. We also find curious similarities between the behaviour of the VeV $\\langle \\Phi ...

  5. LDA - Measurements of Transitional Flows Induced by a Square Rib

    Energy Technology Data Exchange (ETDEWEB)

    Becker, S.; Durst, F.; Stoots, Carl Marcel; Condie, Keith Glenn; McEligot, Donald Marinus

    2002-03-01

    New fundamental measurements are presented for the transition process in flat plate boundary layers downstream of two-dimensional square ribs. By use of laser Doppler anemometry (LDA) and a large Matched-Index-of-Refraction (MIR) flow system, data for wall-normal fluctuations and Reynolds stresses were obtained in the near wall region to y+<0.1 in addition to the usual mean streamwise velocity component and its fluctuation. By varying velocity and rib height, the experiment investigated the following range of conditions: k+ = 5.5 to 21, 0.3

  6. Application of laser-induced photoacoustic spectroscopy for determination of plutonium concentration in nuclear waste solutions.

    Science.gov (United States)

    Surugaya, Naoki; Sato, Soichi; Jitsukata, Syu; Watahiki, Masaru

    2008-04-01

    Laser-induced photoacoustic spectroscopy was used in a quantitative analysis of Pu in HNO3 medium. Plutonium was quantitatively oxidized to Pu(VI) using Ce(IV). The photoacoustic measurement of Pu(VI) with maximum absorption at 830.5 nm was subsequently performed to determine the concentration. The photoacoustic signal was linearly proportional to the Pu(VI) ion concentration. The detection limit of Pu(VI) was estimated to be 0.5 microg mL(-1) (3sigma) in 3 M HNO3. By the proposed method, Pu concentration was successfully determined in a nuclear waste solution for use in nuclear materials management.

  7. Realistic calculations of nuclear disappearance lifetimes induced by n nmacr oscillations

    Science.gov (United States)

    Friedman, E.; Gal, A.

    2008-07-01

    Realistic calculations of nuclear disappearance lifetimes induced by n nmacr oscillations are reported for oxygen and iron, using nmacr nuclear potentials derived from a recent comprehensive analysis of pmacr atomic X-ray and radiochemical data. A lower limit τn nmacr >3.3×108s on the n nmacr oscillation time is derived from the Super-Kamiokande I new lower limit Td(O)>1.77×1032yr on the neutron lifetime in oxygen. Antineutron scattering lengths in carbon and nickel, needed in trap experiments using ultracold neutrons, are calculated from updated Nmacr optical potentials at threshold, with results shown to be largely model independent.

  8. Experimental and Theoretical Search for a Phase Transition in Nuclear Fragmentation

    CERN Document Server

    Chbihi, A; Salou, S; Gross, D H E

    1999-01-01

    Phase transitions of small isolated systems are signaled by the shape of the caloric equation of state e^*(T), the relationship between the excitation energy per nucleon e^* and temperature. In this work we compare the experimentally deduced e^*(T) to the theoretical predictions. The experimentally accessible temperature was extracted from evaporation spectra from incomplete fusion reactions leading to residue nuclei. The experimental e^*(T) dependence exhibits the characteristic S-shape at e^* = 2-3 MeV/A. Such behavior is expected for a finite system at a phase transition. The observed dependence agrees with predictions of the MMMC-model, which simulates the total accessible phase-space of fragmentation.

  9. Experimental and theoretical search for a phase transition in nuclear fragmentation

    Science.gov (United States)

    Chbihi, A.; Schapiro, O.; Salou, S.; Gross, D. H. E.

    Phase transitions of small isolated systems are signaled by the shape of the caloric equation of state e*(T), the relationship between the excitation energy per nucleon e* and temperature. In this work we compare the experimentally deduced e*(T) to the theoretical predictions. The experimentally accessible temperature was extracted from evaporation spectra from incomplete fusion reactions leading to residue nuclei. The experimental e*(T) dependence exhibits the characteristic S-shape at e*= 2-3 MeV/A. Such behavior is expected for a finite system at a phase transition. The observed dependence agrees with predictions of the MMMC-model, which simulates the total accessible phase-space of fragmentation.

  10. Transition between nuclear and quark-gluon descriptions of hadrons and light nuclei.

    Science.gov (United States)

    Holt, R J; Gilman, R

    2012-08-01

    We provide a perspective on studies aimed at observing the transition between hadronic and quark-gluonic descriptions of reactions involving light nuclei. We begin by summarizing the results for relatively simple reactions such as the pion form factor and the neutral pion transition form factor as well as that for the nucleon and end with exclusive photoreactions in our simplest nuclei. A particular focus will be on reactions involving the deuteron. It is noted that a firm understanding of these issues is essential for unravelling important structure information from processes such as deeply virtual Compton scattering as well as deeply virtual meson production. The connection to exotic phenomena such as color transparency will be discussed. A number of outstanding challenges will require new experiments at modern facilities on the horizon as well as further theoretical developments.

  11. High Energy Rate Forming Induced Phase Transition in Austenitic Steel

    Science.gov (United States)

    Kovacs, T.; Kuzsella, L.

    2017-02-01

    In this study, the effects of explosion hardening on the microstructure and the hardness of austenitic stainless steel have been studied. The optimum explosion hardening technology of austenitic stainless steel was researched. In case of the explosive hardening used new idea means indirect hardening setup. Austenitic stainless steels have high plasticity and can be cold formed easily. However, during cold processing the hardening phenomena always occurs. Upon the explosion impact, the deformation mechanism indicates a plastic deformation and this deformation induces a phase transformation (martensite). The explosion hardening enhances the mechanical properties of the material, includes the wear resistance and hardness [1]. In case of indirect hardening as function of the setup parameters specifically the flayer plate position the hardening increased differently. It was find a relationship between the explosion hardening setup and the hardening level.

  12. The pressure-induced phase transition of Ga sub 2 O sub 3

    CERN Document Server

    Tu Bao Zhao; Xu Peng; Wang Xin; Gao Wei; Wang Cheng Xin; LiuJing; Zou Guang Tian

    2002-01-01

    In this paper, we investigate the pressure-induced structural transition of alpha-Ga sub 2 O sub 3 powder by means of energy-dispersive x-ray diffraction (EDXD) measurements. The EDXD results show that, with increase of pressure, a new pressure-induced phase appears. The new tetragonal structure (beta-Ga sub 2 O sub 3) can remain stable over the pressure range (<=38 GPa) under study.

  13. Snail2 is an essential mediator of Twist1-induced epithelial-mesenchymal transition and metastasis

    OpenAIRE

    Casas, Esmeralda; Kim, Jihoon; Bendesky, Andrés; Ohno-Machado, Lucila; Wolfe, Cecily J.; Yang, Jing

    2011-01-01

    To metastasize, carcinoma cells must attenuate cell-cell adhesion to disseminate into distant organs. A group of transcription factors, including Twist1, Snail1, Snail2, ZEB1, and ZEB2, have been shown to induce Epithelial-Mesenchymal Transition (EMT), thus promoting tumor dissemination. However, it is unknown whether these transcription factors function independently or coordinately to activate the EMT program. Here we report that direct induction of Snail2 is essential for Twist1 to induce ...

  14. Successful transition to buprenorphine in a patient with methadone-induced torsades de pointes.

    Science.gov (United States)

    Esses, Jason Levi; Rosman, Jonathan; Do, Lien Thanh; Schweitzer, Paul; Hanon, Sam

    2008-11-01

    A 56-year-old-man presented with syncope and torsades de pointes secondary to methadone-induced QT prolongation. After transition from methadone to buprenorphine, a partial mu-opiate-receptor agonist and a kappa-opiate-receptor antagonist, the QT normalized and ventricular arrhythmias resolved. Buprenorphine should be used for opiate dependence and chronic pain in patients with methadone-induced QT prolongation and as first line therapy in patients with risk factors for torsades de pointes.

  15. High-speed laminar-turbulent boundary layer transition induced by a discrete roughness element

    Science.gov (United States)

    Iyer, Prahladh; Mahesh, Krishnan

    2013-11-01

    Direct numerical simulation (DNS) is used to study laminar to turbulent transition induced by a discrete hemispherical roughness element in a high-speed laminar boundary layer. The simulations are performed under conditions matching the experiments of Danehy et al. (AIAA Paper 2009-394, 2009) for free-stream Mach numbers of 3.37, 5.26 and 8.23. It is observed that the Mach 8.23 flow remains laminar downstream of the roughness, while the lower Mach numbers undergo transition. The Mach 3.37 flow undergoes transition closer to the bump when compared with Mach 5.26, in agreement with experimental observations. Transition is accompanied by an increase in Cf and Ch (Stanton number). Even for the case that did not undergo transition (Mach 8.23), streamwise vortices induced by the roughness cause a significant rise in Cf until 20 D downstream. The mean van Driest transformed velocity and Reynolds stress for Mach 3.37 and 5.26 show good agreement with available data. A local Reynolds number based on the wall properties is seen to correlate with the onset of transition for the cases considered. Partially supported by NASA.

  16. Reexamination of Nuclear Shape Transitions in Gadolinium and Dysprosium Isotopes Chains by Using the Geometric Collective Model

    Directory of Open Access Journals (Sweden)

    Khalaf A. M.

    2014-01-01

    Full Text Available The critical points of potential energy surface (PES’s of the limits of nuclear struc- ture harmonic oscillator, axially symmetric rotor and deformed -soft and discussed in framework of the general geometric collective model (GCM. Also the shape phase transitions linking the three dynamical symmetries are studied taking into account only three parameters in the PES’s. The model is tested for the case of 238 92 U , which shows a more prolate behavior. The optimized model parameters have been adjusted by fit- ting procedure using a simulated search program in order to reproduce the experimental excitation energies in the ground state band up to 6 + and the two neutron separation energies.

  17. Relation between molecular electronic structure and nuclear spin-induced circular dichroism

    DEFF Research Database (Denmark)

    Štěpánek, Petr; Coriani, Sonia; Sundholm, Dage

    2017-01-01

    The recently theoretically described nuclear spin-induced circular dichroism (NSCD) is a promising method for the optical detection of nuclear magnetization. NSCD involves both optical excitations of the molecule and hyperfine interactions and, thus, it offers a means to realize a spectroscopy...... with spatially localized, high-resolution information. To survey the factors relating the molecular and electronic structure to the NSCD signal, we theoretically investigate NSCD of twenty structures of the four most common nucleic acid bases (adenine, guanine, thymine, cytosine). The NSCD signal correlates...... with the spatial distribution of the excited states and couplings between them, reflecting changes in molecular structure and conformation. This constitutes a marked difference to the nuclear magnetic resonance (NMR) chemical shift, which only reflects the local molecular structure in the ground electronic state...

  18. Charged particle-induced nuclear fission reactions – Progress and prospects

    Indian Academy of Sciences (India)

    S Kailas; K Mahata

    2014-12-01

    The nuclear fission phenomenon continues to be an enigma, even after nearly 75 years of its discovery. Considerable progress has been made towards understanding the fission process. Both light projectiles and heavy ions have been employed to investigate nuclear fission. An extensive database of the properties of fissionable nuclei has been generated. The theoretical developments to describe the fission phenomenon have kept pace with the progress in the corresponding experimental measurements. As the fission process initiated by the neutrons has been well documented, the present article will be restricted to charged particle-induced fission reactions. The progress made in recent years and the prospects in the area of nuclear fission research will be the focus of this review.

  19. Preparation of Nuclear Spin Singlet States using Spin-Lock Induced Crossing

    CERN Document Server

    DeVience, Stephen J; Rosen, Matthew S

    2013-01-01

    We introduce a broadly applicable technique to create nuclear spin singlet states in organic molecules and other many-atom systems. We employ a novel pulse sequence to produce a spin-lock induced crossing (SLIC) of the spin singlet and triplet energy levels, which enables triplet/singlet polarization transfer and singlet state preparation. We demonstrate the utility of the SLIC method by producing a long-lived nuclear spin singlet state on two strongly-coupled proton pairs in the tripeptide molecule phenylalanine-glycine-glycine dissolved in D2O, and by using SLIC to measure the J-couplings, chemical shift differences, and singlet lifetimes of the proton pairs. We show that SLIC is more efficient at creating nearly-equivalent nuclear spin singlet states than previous pulse sequence techniques, especially when triplet/singlet polarization transfer occurs on the same timescale as spin-lattice relaxation.

  20. Moderate bending strain induced semiconductor to metal transition in Si nanowires

    Science.gov (United States)

    Rabbani, M. Golam; Patil, Sunil R.; Anantram, M. P.

    2016-12-01

    A moderate amount of bending strains, ∼3% is found to be enough to induce the semiconductor-metal transition in Si nanowires of ∼4 nm diameter. The influence of bending on silicon nanowires of 1 nm to 4.3 nm diameter is investigated using molecular dynamics and quantum transport simulations. Local strains in nanowires are analyzed along with the effect of bending strain and nanowire diameter on electronic transport and the transmission energy gap. Interestingly, relatively wider nanowires are found to undergo semiconductor-metal transition at relatively lower bending strains. The effect of bending strain on electronic properties is then compared with the conventional way of straining, i.e. uniaxial, which shows that bending is a much more efficient way of straining to enhance the electronic transport and also to induce the semiconductor-metal transition in experimentally realizable Si nanowires.

  1. On the changeover timescales of technology transitions and induced efficiency changes: an overarching theory

    CERN Document Server

    Mercure, Jean-Francois

    2012-01-01

    This paper presents a general theory that aims at explaining timescales observed empirically in technology transitions and predicting those of future transitions. This framework is used further to derive a theory for exploring the dynamics that underlie the complex phenomenon of irreversible and path dependent price or policy induced efficiency changes. Technology transitions are known to follow patterns well described by logistic functions, which should more rigorously be modelled mathematically using the Lotka-Volterra family of differential equations, originally developed to described the population growth of competing species. The dynamic evolution of technology has also been described theoretically using evolutionary dynamics similar to that observed in nature. The theory presented here joins both approaches and presents a methodology for predicting changeover time constants in order to describe real systems of competing technologies. The problem of price or policy induced efficiency changes becomes natu...

  2. Magnetostrictive hypersound generation by spiral magnets in the vicinity of magnetic field induced phase transition

    Science.gov (United States)

    Bychkov, Igor V.; Kuzmin, Dmitry A.; Kamantsev, Alexander P.; Koledov, Victor V.; Shavrov, Vladimir G.

    2016-11-01

    In present work we have investigated magnetostrictive ultrasound generation by spiral magnets in the vicinity of magnetic field induced phase transition from spiral to collinear state. We found that such magnets may generate transverse sound waves with the wavelength equal to the spiral period. We have examined two types of spiral magnetic structures: with inhomogeneous exchange and Dzyaloshinskii-Moriya interactions. Frequency of the waves from exchange-caused spiral magnetic structure may reach some THz, while in case of Dzyaloshinskii-Moriya interaction-caused spiral it may reach some GHz. These waves will be emitted like a sound pulses. Amplitude of the waves is strictly depends on the phase transition speed. Some aspects of microwaves to hypersound transformation by spiral magnets in the vicinity of phase transition have been investigated as well. Results of the work may be interesting for investigation of phase transition kinetics as well, as for various hypersound applications.

  3. Pressure Induced Suppression to the Valence Change Transition in EuPdAs

    Directory of Open Access Journals (Sweden)

    Baoxuan Li

    2015-01-01

    Full Text Available By applying a hydrostatic pressure, we have successfully suppressed the valence change transition in EuPdAs. The studied compound EuPdAs crystallizes in a P63/mmc space group. Through resistivity and magnetic susceptibility measurements, we find that EuPdAs shows a phase transition at 180 K and another transition below 10 K at ambient pressure, as was reported before. The overall transport and magnetic behavior is to some extent similar to that of the parent phase of iron based superconductors. With application of a hydrostatic pressure, the transition at 180 K is sensitively suppressed with a pressure as low as 0.48 GPa. However, superconductivity has not been induced with pressure up to 1.90 GPa.

  4. Transition radiation at radio frequencies from ultra-high energy neutrino-induced showers

    CERN Document Server

    Motloch, Pavel; Privitera, Paolo; Zas, Enrique

    2015-01-01

    Coherent radiation at radio frequencies from high-energy showers fully contained in a dense radio-transparent medium - like ice, salt or regolith - has been extensively investigated as a promising technique to search for ultra-high energy (UHE) neutrinos. Additional emission in the form of transition radiation may occur when a neutrino-induced shower produced close to the Earth surface emerges from the ground into atmospheric air. We present the first detailed evaluation of transition radiation from high-energy showers crossing the boundary between two different media. We found that transition radiation is sizable over a wide solid angle and coherent up to $\\sim$ 1 GHz. These properties encourage further work to evaluate the potential of a large-aperture UHE neutrino experiment based on detection of transition radiation.

  5. Thermally Induced Phase Transitions of CsHSO 4: A Reexamination

    Science.gov (United States)

    Rangavittal, N.; Row, T. N. Guru; Rao, C. N. R.

    1995-07-01

    A reexamination of the thermally induced phase transitions of CsHSO4 shows that the room-temperature phase IV transforms to II around 373 K. Phase III is, however, not obtained by heating IV to 340 K. Phases IV and III can coexist at room temperature under certain conditions; and phase III appears to transform to II at 340 K.

  6. Transitions between levels of a quantum bouncer induced by a noise-like perturbation

    Science.gov (United States)

    Codau, C.; Nesvizhevsky, V. V.; Fertl, M.; Pignol, G.; Protasov, K. V.

    2012-06-01

    The probability of transition between levels of a quantum bouncer, induced by a noise-like perturbation, is calculated. The results are applied to two sources of noise (vibrations and mirror surface waviness) which might play an important role in future GRANIT experiment, aiming at precision studies of/with the neutron quantum bouncer.

  7. Transitions between levels of a quantum bouncer induced by a noise-like perturbation

    CERN Document Server

    Codau, C; Fertl, M; Pignol, G; Protasov, K V

    2012-01-01

    The probability of transition between levels of a quantum bouncer, induced by a noise-like perturbation, is calculated. The results are applied to two sources of noise (vibrations and mirror surface waviness) which might play an important role in future GRANIT experiment, aiming at precision studies of/with the neutron quantum bouncer.

  8. Transitions between levels of a quantum bouncer induced by a noise-like perturbation

    Energy Technology Data Exchange (ETDEWEB)

    Codau, C.; Nesvizhevsky, V.V. [ILL, 6 rue Jules Horowitz, Grenoble F-38042 (France); Fertl, M. [ILL, 6 rue Jules Horowitz, Grenoble F-38042 (France); Paul Scherrer Institut, 5232 Villigen (Switzerland); Pignol, G., E-mail: guillaume.pignol@lpsc.in2p3.fr [Laboratoire de Physique Subatomique et de Cosmologie, Universite Joseph Fourier-CNRS/IN2P3-INPG, Grenoble (France); Protasov, K.V. [Laboratoire de Physique Subatomique et de Cosmologie, Universite Joseph Fourier-CNRS/IN2P3-INPG, Grenoble (France)

    2012-06-11

    The probability of transition between levels of a quantum bouncer, induced by a noise-like perturbation, is calculated. The results are applied to two sources of noise (vibrations and mirror surface waviness) which might play an important role in future GRANIT experiment, aiming at precision studies of/with the neutron quantum bouncer.

  9. Supramolecular chemical shift reagents inducing conformational transitions: NMR analysis of carbohydrate homooligomer mixtures

    DEFF Research Database (Denmark)

    Beeren, Sophie; Meier, Sebastian

    2015-01-01

    We introduce the concept of supramolecular chemical shift reagents as a tool to improve signal resolution for the NMR analysis of homooligomers. Non-covalent interactions with the shift reagent can constrain otherwise flexible analytes inducing a conformational transition that results in signal s...

  10. TR PIV Experimental Investigation on Bypass Transition Induced by a Cylinder Wake

    Institute of Scientific and Technical Information of China (English)

    TANG Zhan-Qi; JIANG Nan

    2011-01-01

    @@ The process of laminar to turbulent transition induced by a cylinder wake is studied by time-resolved(TR)particle image velocimetry(PIV) in a water channel.The combination of multi-scale local-averaged structure function analysis with criteria is used to identify the generation of secondary transverse vortex structure andto track its evolution along the streamvise.At the beginning of transition,with the decent of cylinder wake vortex,the secondary vortex structure is induced near the vall.As the secondary vortex moves dovnstream,it is induced to lift up by the wake vortex,meanwhile they are diffused and dissipated.According to the method of spatial conditional average,a low-speedhump is found in the near-wallregion along the bypass transition zone,accompanied by a low-speed region in the free stream occupied by the vake vortex.With further downstream,the hump in the near-wall region becomes more and more obvious.At the later stage of transition zone,hairpin vortex can be seen by conditional-averaged low-pass filtered vorticity.The hairpin head is almost vertical to the wall with an inclination angle of about 90°,which is attributed to the additional lift-up behavior induced by wake vortex.It can be concluded that in the process of bypass transition,the wake vortex would not only induce the secondary vortex but also leaven its growth and evolution,resulting in the robust and rapidly growing hairpin vortex.%The process of laminar to turbulent transition induced by a cylinder wake is studied by time-resolved (TR)particle image velocimetry (PIV) in a water channel. The combination of multi-scale local-averaged structure function analysis with criteria is used to identify the generation of secondary transverse vortex structure and to track its evolution along the streamwise. At the beginning of transition, with the decent of cylinder wake vortex, the secondary vortex structure is induced near the wall. As the secondary vortex moves downstream, it is induced to lift

  11. Noise-induced transitions and resonant effects in nonlinear systems

    Science.gov (United States)

    Zaikin, Alexei

    2003-02-01

    Our every-day experience is connected with different acoustical noise or music. Usually noise plays the role of nuisance in any communication and destroys any order in a system. Similar optical effects are known: strong snowing or raining decreases quality of a vision. In contrast to these situations noisy stimuli can also play a positive constructive role, e.g. a driver can be more concentrated in a presence of quiet music. Transmission processes in neural systems are of especial interest from this point of view: excitation or information will be transmitted only in the case if a signal overcomes a threshold. Dr. Alexei Zaikin from the Potsdam University studies noise-induced phenomena in nonlinear systems from a theoretical point of view. Especially he is interested in the processes, in which noise influences the behaviour of a system twice: if the intensity of noise is over a threshold, it induces some regular structure that will be synchronized with the behaviour of neighbour elements. To obtain such a system with a threshold one needs one more noise source. Dr. Zaikin has analyzed further examples of such doubly stochastic effects and developed a concept of these new phenomena. These theoretical findings are important, because such processes can play a crucial role in neurophysics, technical communication devices and living sciences. Unsere alltägliche Erfahrung ist mit verschiedenen akustischen Einfluessen wie Lärm, aber auch Musik verbunden. Jeder weiss, wie Lärm stören kann und Kommunikation behindert oder gar unterbindet. Ähnliche optische Effekte sind bekannt: starkes Schneetreiben oder Regengüsse verschlechtern die Sicht und lassen uns Umrisse nur noch schemenhaft erkennen. Jedoch koennen ähnliche Stimuli auch sehr positive Auswirkungen haben: Autofahrer fahren bei leiser Musik konzentrierter -- die Behauptung von Schulkindern, nur bei dröhnenden Bässen die Mathehausaufgaben richtig rechnen zu können, ist allerdings nicht wissenschaftlich

  12. Nuclear envelope breakdown induced by herpes simplex virus type 1 involves the activity of viral fusion proteins

    Energy Technology Data Exchange (ETDEWEB)

    Maric, Martina; Haugo, Alison C. [Department of Microbiology, University of Iowa, Iowa City, IA 52242 (United States); Dauer, William [Department of Neurology, University of Michigan, Ann Arbor, MI 48109 (United States); Johnson, David [Department of Microbiology and Immunology, Oregon Health Sciences University, Portland, OR 97201 (United States); Roller, Richard J., E-mail: richard-roller@uiowa.edu [Department of Microbiology, University of Iowa, Iowa City, IA 52242 (United States)

    2014-07-15

    Herpesvirus infection reorganizes components of the nuclear lamina usually without loss of integrity of the nuclear membranes. We report that wild-type HSV infection can cause dissolution of the nuclear envelope in transformed mouse embryonic fibroblasts that do not express torsinA. Nuclear envelope breakdown is accompanied by an eight-fold inhibition of virus replication. Breakdown of the membrane is much more limited during infection with viruses that lack the gB and gH genes, suggesting that breakdown involves factors that promote fusion at the nuclear membrane. Nuclear envelope breakdown is also inhibited during infection with virus that does not express UL34, but is enhanced when the US3 gene is deleted, suggesting that envelope breakdown may be enhanced by nuclear lamina disruption. Nuclear envelope breakdown cannot compensate for deletion of the UL34 gene suggesting that mixing of nuclear and cytoplasmic contents is insufficient to bypass loss of the normal nuclear egress pathway. - Highlights: • We show that wild-type HSV can induce breakdown of the nuclear envelope in a specific cell system. • The viral fusion proteins gB and gH are required for induction of nuclear envelope breakdown. • Nuclear envelope breakdown cannot compensate for deletion of the HSV UL34 gene.

  13. Calculation of the Nuclear Transition Charge Density in a Microscopic sdgIBM-1

    Institute of Scientific and Technical Information of China (English)

    ZHANG Zhan-Jun; SANG Jian-ping; LIU Yong

    2000-01-01

    Formulae of proton and neutron boson structure functions (BSF's) are deduced in terms of a microscopic approach of sdgIBM (namely, microscopic sdgIBM). For the nucleus 190Os, the value of BSF's is worked out. Due to the high similarity, the maximum F-spin truncation is made under the full-symmetry approximation. Thereafter, calculations of E2 and E4 transition charge densities (TCD's) are performed in the sdgIBM-1. It is found that the E2 and E4 TCD's can be reproduced quite satisfactorily in the uniform frame of microscopic sdgIBM-1.

  14. Description of Induced Nuclear Fission with Skyrme Energy Functionals: II. Finite Temperature Effects

    CERN Document Server

    Schunck, N; Carr, H

    2013-01-01

    Understanding the mechanisms of induced nuclear fission for a broad range of neutron energies could help resolve fundamental science issues, such as the formation of elements in the universe, but could have also a large impact on societal applications in energy production of nuclear waste management. The goal of this paper is to set up the foundations of a microscopic model to study the static aspects of induced fission as a function of the excitation energy of the incident neutron, from thermal to fast neutrons. To account for the high excitation energy of the compound nucleus, we employ a statistical approach based on finite temperature nuclear density functional theory with Skyrme energy densities, which we benchmark on the fission of 239Pu(n,f). We compute the evolution of the least-energy fission pathway across multidimensional potential energy surfaces with up to five collective variables as a function of the nuclear temperature, and predict the evolution of both the inner and outer fission barriers as ...

  15. Retinoic acid induces nuclear accumulation of Raf1 during differentiation of HL-60 cells.

    Science.gov (United States)

    Smith, James; Bunaciu, Rodica P; Reiterer, Gudrun; Coder, David; George, Thaddeus; Asaly, Michael; Yen, Andrew

    2009-08-01

    All trans-retinoic acid (RA) is a standard therapeutic agent used in differentiation induction therapy treatment of acute promyelocytic leukemia (APL). RA and its metabolites use a diverse set of signal transduction pathways during the differentiation program. In addition to the direct transcriptional targets of the nuclear RAR and RXR receptors, signals derived from membrane receptors and the Raf-MEK-ERK pathway are required. Raf1 phosphorylation and the prolonged activation of Raf1 persisting during the entire differentiation process are required for RA-dependent differentiation of HL-60 cells. Here we identify a nuclear redistribution of Raf1 during the RA-induced differentiation of HL-60 cells. In addition, the nuclear accumulation of Raf1 correlates with an increase in Raf1 phosphorylated at serine 621. The serine 621 phosphorylated Raf1 is predominantly localized in the nucleus. The RA-dependent nuclear accumulation of Raf1 suggests a novel nuclear role for Raf1 during the differentiation process.

  16. Retinoic acid induces nuclear accumulation of Raf1 during differentiation of HL-60 cells

    Energy Technology Data Exchange (ETDEWEB)

    Smith, James; Bunaciu, Rodica P.; Reiterer, Gudrun [Department of Biomedical Sciences, T4-008 VRT, Cornell University, Ithaca, NY 14853 (United States); Coder, David; George, Thaddeus [Amnis Corporation, Seattle, Washington (United States); Asaly, Michael [Department of Biomedical Sciences, T4-008 VRT, Cornell University, Ithaca, NY 14853 (United States); Yen, Andrew, E-mail: ay13@cornell.edu [Department of Biomedical Sciences, T4-008 VRT, Cornell University, Ithaca, NY 14853 (United States)

    2009-08-01

    All trans-retinoic acid (RA) is a standard therapeutic agent used in differentiation induction therapy treatment of acute promyelocytic leukemia (APL). RA and its metabolites use a diverse set of signal transduction pathways during the differentiation program. In addition to the direct transcriptional targets of the nuclear RAR and RXR receptors, signals derived from membrane receptors and the Raf-MEK-ERK pathway are required. Raf1 phosphorylation and the prolonged activation of Raf1 persisting during the entire differentiation process are required for RA-dependent differentiation of HL-60 cells. Here we identify a nuclear redistribution of Raf1 during the RA-induced differentiation of HL-60 cells. In addition, the nuclear accumulation of Raf1 correlates with an increase in Raf1 phosphorylated at serine 621. The serine 621 phosphorylated Raf1 is predominantly localized in the nucleus. The RA-dependent nuclear accumulation of Raf1 suggests a novel nuclear role for Raf1 during the differentiation process.

  17. Induced magnetic ordering transition in RCo{sub 5} type materials

    Energy Technology Data Exchange (ETDEWEB)

    Rivin, Oleg, E-mail: drorivin@gmail.com [Department of Physics, Nuclear Research Center – Negev, P.O. Box 9001, Beer Sheva 84190 (Israel); Department of Physics, Ben-Gurion University, P.O. Box 653, Beer Sheva 84105 (Israel); Shaked, Hagai [Department of Physics, Ben-Gurion University, P.O. Box 653, Beer Sheva 84105 (Israel); Caspi, El’ad N. [Department of Physics, Nuclear Research Center – Negev, P.O. Box 9001, Beer Sheva 84190 (Israel)

    2015-09-15

    The magnetism in several materials of the RCo{sub 5} type is studied. A numerical calculation scheme, based on an induced magnetic ordering transition, is set up. Using this scheme, and previously reported crystalline electric and magnetic exchange fields parameters, the magnetic structure in R{sub 1−y}Y{sub y}Co{sub 3}B{sub 2} and R(Co{sub 1−x}Ni{sub x}){sub 5} materials (R=Tb and Ho), and its temperature evolution, is calculated, and compared with the corresponding observed results. It is proposed that the magnetic order in the materials of the RCO{sub 5} type, with R{sup 3+} of integral J, is driven by an induced transition. - Highlights: • A numerical calculations scheme, that simulates induced transition magnetic ordering in R{sub 1−y}YyCo{sub 3}B{sub 2} and R(Co{sub 1−x}Ni{sub x}){sub 5} type materials, is set up. • The observed ordered magnetic moment of the R sub-lattice, as function of the magnetic exchange field, and as function of temperature, is shown to agree with induced transition theory, and not with Curie–Weiss theory. • In R{sub 1−y}Y{sub y}Co{sub 3}B{sub 2}, the relative magnitudes of the crystalline electric field and the magnetic exchange field are just above the critical threshold for induced transition ordering, making them the best experimental ‘realization’ found so far.

  18. High field nuclear magnetic resonance in transition metal substituted BaFe{sub 2}As{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Garitezi, T. M., E-mail: thalesmg@ifi.unicamp.br; Lesseux, G. G.; Rosa, P. F. S.; Adriano, C.; Pagliuso, P. G.; Urbano, R. R. [Instituto de Física “Gleb Wataghin,” UNICAMP, Campinas, SP 13083-859 (Brazil); Reyes, A. P.; Kuhns, P. L. [National High Magnetic Field Laboratory, FSU, Tallahassee, Florida 32306-4005 (United States)

    2014-05-07

    We report high field {sup 75}As nuclear magnetic resonance (NMR) measurements on Co and Cu substituted BaFe{sub 2}As{sub 2} single crystals displaying same structural/magnetic transition T{sub 0}≃128  K. From our anisotropy studies in the paramagnetic state, we strikingly found virtually identical quadrupolar splitting and consequently the quadrupole frequency ν{sub Q}≃2.57(1)  MHz for both compounds, despite the claim that each Cu delivers 2 extra 3d electrons in BaFe{sub 2}As{sub 2} compared to Co substitution. These results allow us to conclude that a subtle change in the crystallographic structure, particularly in the Fe–As tetrahedra, must be the most probable tuning parameter to determine T{sub 0} in this class of superconductors rather than electronic doping. Furthermore, our NMR data around T{sub 0} suggest coexistence of tetragonal/paramagnetic and orthorhombic/antiferromagnetic phases between the structural and the spin density wave magnetic phase transitions, similarly to what was reported for K-doped BaFe{sub 2}As{sub 2} [Urbano et al., Phys. Rev. Lett. 105, 107001 (2010)].

  19. Nuclear Phase Transition from Spherical to Axially Symmetric Deformed Shapes Using Interacting Boson Model

    Directory of Open Access Journals (Sweden)

    Khalaf A. M.

    2015-04-01

    Full Text Available The interacting boson model (sd-IBM1 with intrinsic coherent state is used to study the shape phase transitions from spherical U(5 to prolate deformed SU(3 shapes in Nd- Sm isotopic chains. The Hamiltonian is written in the creation and annihilation form with one and two body terms.For each nucleus a fitting procedure is adopted to get the best model parameters by fitting selected experimental energy levels, B(E2 transi- tion rates and two-neutron separation energies with the calculated ones.The U(5-SU(3 IBM potential energy surfaces (PES’s are analyzed and the critical phase transition points are identified in the space of model parameters.In Nd-Sm isotopic chains nuclei evolve from spherical to deformed shapes by increasing the boson number. The nuclei 150 Nd and 152 Sm have been found to be close to critical points.We have also studied the energy ratios and the B(E2 values for yrast band at the critical points.

  20. EGF induces epithelial-mesenchymal transition through phospho-Smad2/3-Snail signaling pathway in breast cancer cells.

    Science.gov (United States)

    Kim, Jinkyoung; Kong, Jienan; Chang, Hyeyoon; Kim, Hayeon; Kim, Aeree

    2016-12-20

    Epithelial-mesenchymal transition (EMT) can contribute to tumor invasion, metastasis, and resistance to chemotherapy or hormone therapy. EMT may be induced by a variety of growth factors, such as epidermal growth factor (EGF). Most studies regarding EMT have focused on TGF-β-Smads signaling. The mechanism of EGF-induced EMT via activation of the Smad2/3 in breast cancer cells, MCF-7 and MDA-MB-231, remains unclear. The expression levels of Snail, vimentin, and fibronectin were increased by EGF treatment in a time-dependent manner, while the expression level of E-cadherin was decreased. EGF-induced nuclear co-localization of phospho-Smad2/3 and Snail and cancer cell migration were inhibited by pretreatment with an ERK1/2 inhibitor, PD98059 and a phospho-Smad2 inhibitor, SB203580. Knockdown of Smad2/3 expression suppressed EGF-induced expressions of Snail, vimentin, fibronectin, and cancer cell invasion, suggesting an acquisition of the mesenchymal and migratory phenotype in less aggressive MCF-7 cells. Moreover, MDA-MB-231 cells were shown that EGF-induced EMT, and cell invasion through ERK1/2-phospho-Smad2/3-Snail signaling pathway. We have discovered that EGF-stimulated activation of Smad2/3 upregulated several key EMT markers, inhibited E-cadherin expression, promoted EMT, enhanced migration and invasion in MCF-7 and MDA-MB-231 breast cancer cells. Identification of this molecular mechanism may provide new molecular targets for the development of therapies for metastatic breast cancer.

  1. Shear-induced nano-macro structural transition in a polymeric bicontinuous microemulsion

    DEFF Research Database (Denmark)

    Krishnan, K.; Almdal, K.; Burghardt, W.R.

    2001-01-01

    Bicontinuous microemulsions arise in a narrow concentration range for ternary blends containing two immiscible homopolymers and the corresponding diblock copolymer. Steady shear reveals four distinct regimes of response as a function of shear rate, corresponding to flow-induced transitions in fluid...... structure. In situ neutron scattering shows flow-induced anisotropy in the nanometer-scale microemulsion structure at moderate shear rates, while higher rates induce bulk phase separation, with micron-size morphology, which is characterized with in situ light scattering and optical microscopy....

  2. "Dot COM", a nuclear transit center for the primary piRNA pathway in Drosophila.

    Science.gov (United States)

    Dennis, Cynthia; Zanni, Vanessa; Brasset, Emilie; Eymery, Angeline; Zhang, Liang; Mteirek, Rana; Jensen, Silke; Rong, Yikang S; Vaury, Chantal

    2013-01-01

    The piRNA pathway protects genomes by silencing mobile elements. Despite advances in understanding the processing events that generate piRNAs for silencing, little is known about how primary transcripts are transported from their genomic clusters to their processing centers. Using a model of the Drosophila COM/flamenco locus in ovarian somatic cells, we identified a prominent nuclear structure called Dot COM, which is enriched in long transcripts from piRNA clusters but located far from their transcription sites. Remarkably, transcripts from multiple clusters accumulate at Dot COM, which is often juxtaposed with Yb-bodies, the cytoplasmic processing centers for cluster transcripts. Genetic evidence suggests that the accumulation of precursor transcripts at Dot COM represents one of the most upstream events in the piRNA pathway. Our results provide new insights into the initial steps of the piRNA pathway, and open up a new research area important for a complete understanding of this conserved pathway.

  3. The transition from silicon to gas detection media in nuclear physics

    Energy Technology Data Exchange (ETDEWEB)

    Pollacco, Emanuel C., E-mail: epollacco@cea.fr

    2016-06-01

    Emerging radioactive beams and multi petawatt laser facilities are sturdily transforming our base concepts in instruments in nuclear physics. The changes are fuelled by studies of nuclei close to the drip-line or exotic reactions. This physics demands high luminosity, wide phase space cover with good resolution in energy, time, position and sampled waveform. By judiciously modifying the micro-world of the particle or space physics instruments (Double Sided Strip Si Detectors, Micro-Pattern Gas Amplifiers, microelectronics), we are on the path to initiate dream experiments. In the following a brief status in the domain is reported for selected instruments that highlight the present trends with silicon and the growing shift towards gas media for charged particle detection.

  4. Stress-induced Nuclear Bodies Are Sites of Accumulation of Pre-mRNA Processing Factors

    Science.gov (United States)

    Denegri, Marco; Chiodi, Ilaria; Corioni, Margherita; Cobianchi, Fabio; Riva, Silvano; Biamonti, Giuseppe

    2001-01-01

    Heterogeneous nuclear ribonucleoprotein (hnRNP) HAP (hnRNP A1 interacting protein) is a multifunctional protein with roles in RNA metabolism, transcription, and nuclear structure. After stress treatments, HAP is recruited to a small number of nuclear bodies, usually adjacent to the nucleoli, which consist of clusters of perichromatin granules and are depots of transcripts synthesized before stress. In this article we show that HAP bodies are sites of accumulation for a subset of RNA processing factors and are related to Sam68 nuclear bodies (SNBs) detectable in unstressed cells. Indeed, HAP and Sam68 are both present in SNBs and in HAP bodies, that we rename “stress-induced SNBs.” The determinants required for the redistribution of HAP lie between residue 580 and 788. Different portions of this region direct the recruitment of the green fluorescent protein to stress-induced SNBs, suggesting an interaction of HAP with different components of the bodies. With the use of the 580–725 region as bait in a two-hybrid screening, we have selected SRp30c and 9G8, two members of the SR family of splicing factors. Splicing factors are differentially affected by heat shock: SRp30c and SF2/ASF are efficiently recruited to stress-induced SNBs, whereas the distribution of SC35 is not perturbed. We propose that the differential sequestration of splicing factors could affect processing of specific transcripts. Accordingly, the formation of stress-induced SNBs is accompanied by a change in the splicing pattern of the adenovirus E1A transcripts. PMID:11694584

  5. Retinoids induce integrin-independent lymphocyte adhesion through RAR-α nuclear receptor activity

    Energy Technology Data Exchange (ETDEWEB)

    Whelan, Jarrett T.; Wang, Lei; Chen, Jianming; Metts, Meagan E.; Nasser, Taj A.; McGoldrick, Liam J. [Department of Biochemistry and Molecular Biology, The Brody School of Medicine at East Carolina University, Greenville, NC 27834 (United States); Bridges, Lance C., E-mail: bridgesl@ecu.edu [Department of Biochemistry and Molecular Biology, The Brody School of Medicine at East Carolina University, Greenville, NC 27834 (United States); East Carolina Diabetes and Obesity Institute, The Brody School of Medicine at East Carolina University, Greenville, NC 27834 (United States)

    2014-11-28

    Highlights: • Transcription and translation are required for retinoid-induced lymphocyte adhesion. • RAR activation is sufficient to induced lymphocyte cell adhesion. • Vitamin D derivatives inhibit RAR-prompted lymphocyte adhesion. • Adhesion occurs through a novel binding site within ADAM disintegrin domains. • RARα is a key nuclear receptor for retinoid-dependent lymphocyte cell adhesion. - Abstract: Oxidative metabolites of vitamin A, in particular all-trans-retinoic acid (atRA), have emerged as key factors in immunity by specifying the localization of immune cells to the gut. Although it is appreciated that isomers of retinoic acid activate the retinoic acid receptor (RAR) and retinoid X receptor (RXR) family of nuclear receptors to elicit cellular changes, the molecular details of retinoic acid action remain poorly defined in immune processes. Here we employ a battery of agonists and antagonists to delineate the specific nuclear receptors utilized by retinoids to evoke lymphocyte cell adhesion to ADAM (adisintegrin and metalloprotease) protein family members. We report that RAR agonism is sufficient to promote immune cell adhesion in both immortal and primary immune cells. Interestingly, adhesion occurs independent of integrin function, and mutant studies demonstrate that atRA-induced adhesion to ADAM members required a distinct binding interface(s) as compared to integrin recognition. Anti-inflammatory corticosteroids as well as 1,25-(OH){sub 2}D{sub 3}, a vitamin D metabolite that prompts immune cell trafficking to the skin, potently inhibited the observed adhesion. Finally, our data establish that induced adhesion was specifically attributable to the RAR-α receptor isotype. The current study provides novel molecular resolution as to which nuclear receptors transduce retinoid exposure into immune cell adhesion.

  6. Molecular mapping of a new induced gene for nuclear male sterility in sunflower (Helianthus annuus L.)

    Science.gov (United States)

    A new NMS line, NMS HA89-872, induced by mitomycin C and streptomycin carries a single recessive male-sterile gene ms6. An F2 population of 88 plants was obtained from a cross between nuclear male-sterile mutant NMS HA89-872 (msms) and male-fertile line RHA271 (MsMs). 225 SSR primers and 9 RFLP-deri...

  7. Uranium analysis by neutron induced fissionography method using solid state nuclear track detectors

    CERN Document Server

    Akyuez, T; Guezel, T; Akyuz, S

    1999-01-01

    In this study total twenty samples (eight reference materials and twelve sediment samples) were analysed for their uranium content which is in the range of 1-17 mu g/g, by neutron induced fissionography (NIF) method using solid state nuclear track detectors (SSNTDs) in comparison with the results of neutron activation analysis (NAA), delayed neutron counting (DNC) technique or fluorometric method. It is found that NIF method using SSNTDs is very sensitive for analysis of uranium.

  8. Jet-induced modifications of the characteristic of the bulk nuclear matter

    CERN Document Server

    Marcinkowski, P; Kikoła, D; Sikorski, J; Porter-Sobieraj, J; Gawryszewski, P; Zygmunt, B

    2015-01-01

    We present our studies on jet-induced modifications of the characteristic of the bulk nuclear matter. To describe such a matter, we use efficient relativistic hydrodynamic simulations in (3+1) dimensions employing the Graphics Processing Unit (GPU) in the parallel programming framework. We use Cartesian coordinates in the calculations to ensure a high spatial resolution that is constant throughout the evolution of the system. We show our results on how jets modify the hydrodynamics fields and discuss the implications.

  9. Jet-induced modifications of the characteristic of the bulk nuclear matter

    Science.gov (United States)

    Marcinkowski, P.; Słodkowski, M.; Kikoła, D.; Sikorski, J.; Porter-Sobieraj, J.; Gawryszewski, P.; Zygmunt, B.

    2016-01-01

    We present our studies on jet induced modifications of the characteristics of bulk nuclear matter. To describe such matter, we use efficient relativistic hydrodynamic simulations in (3+1)-dimension, employing the Graphics Processing Unit (GPU) in the parallel programming framework. We use Cartesian coordinates in the calculations to ensure a high spatial resolution that is constant throughout the evolution of the system. We show our results on how jets modify the hydrodynamics fields and discuss the implications.

  10. Control of magnetic relaxation by electric-field-induced ferroelectric phase transition and inhomogeneous domain switching

    Energy Technology Data Exchange (ETDEWEB)

    Nan, Tianxiang; Emori, Satoru; Wang, Xinjun; Hu, Zhongqiang; Xie, Li; Gao, Yuan; Lin, Hwaider; Sun, Nian, E-mail: n.sun@neu.edu [Department of Electrical and Computer Engineering, Northeastern University, Boston, Massachusetts 02115 (United States); Peng, Bin; Liu, Ming, E-mail: mingliu@mail.xjtu.edu.cn [Electronic Materials Research Laboratory, Xi' an Jiaotong University, Xi' an 710049 (China); Jiao, Jie; Luo, Haosu [Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 201800 (China); Budil, David [Department of Chemistry, Northeastern University, Boston, Massachusetts 02115 (United States); Jones, John G.; Howe, Brandon M.; Brown, Gail J. [Materials and Manufacturing Directorate, Air Force Research Laboratory, Wright-Patterson AFB, Ohio 45433 (United States)

    2016-01-04

    Electric-field modulation of magnetism in strain-mediated multiferroic heterostructures is considered a promising scheme for enabling memory and magnetic microwave devices with ultralow power consumption. However, it is not well understood how electric-field-induced strain influences magnetic relaxation, an important physical process for device applications. Here, we investigate resonant magnetization dynamics in ferromagnet/ferroelectric multiferroic heterostructures, FeGaB/PMN-PT and NiFe/PMN-PT, in two distinct strain states provided by electric-field-induced ferroelectric phase transition. The strain not only modifies magnetic anisotropy but also magnetic relaxation. In FeGaB/PMN-PT, we observe a nearly two-fold change in intrinsic Gilbert damping by electric field, which is attributed to strain-induced tuning of spin-orbit coupling. By contrast, a small but measurable change in extrinsic linewidth broadening is attributed to inhomogeneous ferroelastic domain switching during the phase transition of the PMN-PT substrate.

  11. Control of magnetic relaxation by electric-field-induced ferroelectric phase transition and inhomogeneous domain switching

    Science.gov (United States)

    Nan, Tianxiang; Emori, Satoru; Peng, Bin; Wang, Xinjun; Hu, Zhongqiang; Xie, Li; Gao, Yuan; Lin, Hwaider; Jiao, Jie; Luo, Haosu; Budil, David; Jones, John G.; Howe, Brandon M.; Brown, Gail J.; Liu, Ming; Sun, Nian

    2016-01-01

    Electric-field modulation of magnetism in strain-mediated multiferroic heterostructures is considered a promising scheme for enabling memory and magnetic microwave devices with ultralow power consumption. However, it is not well understood how electric-field-induced strain influences magnetic relaxation, an important physical process for device applications. Here, we investigate resonant magnetization dynamics in ferromagnet/ferroelectric multiferroic heterostructures, FeGaB/PMN-PT and NiFe/PMN-PT, in two distinct strain states provided by electric-field-induced ferroelectric phase transition. The strain not only modifies magnetic anisotropy but also magnetic relaxation. In FeGaB/PMN-PT, we observe a nearly two-fold change in intrinsic Gilbert damping by electric field, which is attributed to strain-induced tuning of spin-orbit coupling. By contrast, a small but measurable change in extrinsic linewidth broadening is attributed to inhomogeneous ferroelastic domain switching during the phase transition of the PMN-PT substrate.

  12. Glass transition of aqueous solutions involving annealing-induced ice recrystallization resolves liquid-liquid transition puzzle of water.

    Science.gov (United States)

    Zhao, Li-Shan; Cao, Ze-Xian; Wang, Qiang

    2015-10-27

    Liquid-liquid transition of water is an important concept in condensed-matter physics. Recently, it was claimed to have been confirmed in aqueous solutions based on annealing-induced upshift of glass-liquid transition temperature, T(g) . Here we report a universal water-content, X(aqu) , dependence of T(g) for aqueous solutions. Solutions with X(aqu)>X(cr)(aqu)vitrify/devitrify at a constant temperature, ~T(g) , referring to freeze-concentrated phase with X(aqu)left behind ice crystallization. Those solutions with X(aqu)recrystallization is stabilized at . Experiments on aqueous glycerol and 1,2,4-butanetriol solutions in literature were repeated, and the same samples subject to other annealing treatments equally reproduce the result. The upshift of T(g) by annealing is attributable to freeze-concentrated phase of solutions instead of 'liquid II phase of water'. Our work also provides a reliable method to determine hydration formula and to scrutinize solute-solvent interaction in solution.

  13. Stabilization of Snail through AKT/GSK-3β signaling pathway is required for TNF-α-induced epithelial-mesenchymal transition in prostate cancer PC3 cells.

    Science.gov (United States)

    Wang, Hao; Fang, Rui; Wang, Xian-Feng; Zhang, Fan; Chen, Dan-Yang; Zhou, Binhua; Wang, Hong-Sheng; Cai, Shao-Hui; Du, Jun

    2013-08-15

    Metastasis induced by chronic inflammation has been considered as a major challenge during cancer therapy. Epithelial-mesenchymal transition (EMT) is associated with cancer invasion and metastasis promoted by pro-inflammatory cytokine TNFα. However, the mechanisms underlying TNFα-induced EMT in prostate cancer cells is not entirely clear. Here we showed that EMT induced by longstanding stimulation with TNFα in prostate cancer PC3 cells is mediated by up-regulation of the transcriptional repressor Snail. TNFα-mediated EMT was characterized by acquiring mesenchymal fusiform morphology, increasing the expression of Vimentin and decreasing the expression of E-cadherin. Exposure to TNFα increased the expression of transcription factor Snail via post-transcriptional regulation process and induced Snail nuclear localization in PC3 cells. Moreover, overexpressed Snail in PC3 cells induced EMT. Conversely, suppressing Snail expression abrogated TNFα-induced EMT, suggesting that Snail plays a crucial role in TNFα-induced EMT in prostate cancer cells. Finally, we showed that TNFα time-dependently activated NF-κB, AKT, ERK, p38 MAPK signaling pathways, and elevated Snail stability by activating AKT pathway that subsequently inhibited GSK-3β activity. Taken together, these results reveal that stabilization of Snail via AKT/GSK-3β signaling pathway is required for TNFα-induced EMT in prostate cancer cells. This study offers a better understanding of TNFα-induced metastasis and provides an effective therapeutic strategy for prostate cancer treatment. Copyright © 2013 Elsevier B.V. All rights reserved.

  14. Phonon instability and pressure-induced isostructural semiconductor-semimetal transition of monoclinic V O2

    Science.gov (United States)

    He, Huabing; Gao, Heng; Wu, Wei; Cao, Shixun; Hong, Jiawang; Yu, Dehong; Deng, Guochu; Gao, Yanfeng; Zhang, Peihong; Luo, Hongjie; Ren, Wei

    2016-11-01

    Recent experiments have revealed an intriguing pressure-induced isostructural transition of the low temperature monoclinic V O2 and hinted to the existence of a new metallization mechanism in this system. The physics behind this isostructural phase transition and the metallization remains unresolved. In this work, we show that the isostructural transition is a result of pressure-induced instability of a phonon mode that relates to a CaC l2 -type of rotation of the oxygen octahedra, which alleviates, but does not completely remove, the dimerization and zigzagging arrangement of V atoms in the M1 phase. This phonon mode shows an increasing softening with pressure, ultimately leading to an isostructural phase transition characterized by the degree of the rotation of the oxygen octahedra. We also find that this phase transition is accompanied by an anisotropic compression, in excellent agreement with experiments. More interestingly, in addition to the experimentally identified M1' phase, we find a closely related M1 '' phase, which is nearly degenerate with the M1 ' phase. Unlike the M1 ' phase, which has a nearly pressure-independent electronic band gap, the gap of the M1 '' drops quickly at high pressures and vanishes at a theoretical pressure of about 40 GPa.

  15. Surface-induced liquid-gas transition in salt-free solutions of model charged colloids.

    Science.gov (United States)

    Budkov, Yu A; Frolov, A I; Kiselev, M G; Brilliantov, N V

    2013-11-21

    We report a novel phenomenon of a surface-induced phase transition in salt-free solutions of charged colloids. We develop a theory of this effect and confirm it by Molecular Dynamics simulations. To describe the colloidal solution we apply a primitive model of electrolyte with a strong asymmetry of charge and size of the constituent particles - macroions and counterions. To quantify interactions of the colloidal particles with the neutral substrate we use a short-range potential which models dispersion van der Waals forces. These forces cause the attraction of colloids to the surface. We show that for high temperatures and weak attraction, only gradual increase of the macroion concentration in the near-surface layer is observed with increase of interaction strength. If however temperature drops below some threshold value, a new dense (liquid) phase is formed in the near-surface layer. It can be interpreted as a surface-induced first-order phase transition with a critical point. Using an appropriately adopted Maxwell construction, we find the binodal. Interestingly, the observed near-surface phase transition can occur at the absence of the bulk phase transition and may be seemingly classified as prewetting transition. The reported effect could be important for various technological applications where formation of colloidal particle layers with the desired properties is needed.

  16. Protective Effects of Clenbuterol against Dexamethasone-Induced Masseter Muscle Atrophy and Myosin Heavy Chain Transition.

    Science.gov (United States)

    Umeki, Daisuke; Ohnuki, Yoshiki; Mototani, Yasumasa; Shiozawa, Kouichi; Suita, Kenji; Fujita, Takayuki; Nakamura, Yoshiki; Saeki, Yasutake; Okumura, Satoshi

    2015-01-01

    Glucocorticoid has a direct catabolic effect on skeletal muscle, leading to muscle atrophy, but no effective pharmacotherapy is available. We reported that clenbuterol (CB) induced masseter muscle hypertrophy and slow-to-fast myosin heavy chain (MHC) isoform transition through direct muscle β2-adrenergic receptor stimulation. Thus, we hypothesized that CB would antagonize glucocorticoid (dexamethasone; DEX)-induced muscle atrophy and fast-to-slow MHC isoform transition. We examined the effect of CB on DEX-induced masseter muscle atrophy by measuring masseter muscle weight, fiber diameter, cross-sectional area, and myosin heavy chain (MHC) composition. To elucidate the mechanisms involved, we used immunoblotting to study the effects of CB on muscle hypertrophic signaling (insulin growth factor 1 (IGF1) expression, Akt/mammalian target of rapamycin (mTOR) pathway, and calcineurin pathway) and atrophic signaling (Akt/Forkhead box-O (FOXO) pathway and myostatin expression) in masseter muscle of rats treated with DEX and/or CB. Masseter muscle weight in the DEX-treated group was significantly lower than that in the Control group, as expected, but co-treatment with CB suppressed the DEX-induced masseter muscle atrophy, concomitantly with inhibition of fast-to-slow MHC isoforms transition. Activation of the Akt/mTOR pathway in masseter muscle of the DEX-treated group was significantly inhibited compared to that of the Control group, and CB suppressed this inhibition. DEX also suppressed expression of IGF1 (positive regulator of muscle growth), and CB attenuated this inhibition. Myostatin protein expression was unchanged. CB had no effect on activation of the Akt/FOXO pathway. These results indicate that CB antagonizes DEX-induced muscle atrophy and fast-to-slow MHC isoform transition via modulation of Akt/mTOR activity and IGF1 expression. CB might be a useful pharmacological agent for treatment of glucocorticoid-induced muscle atrophy.

  17. Laminopathy-inducing lamin A mutants can induce redistribution of lamin binding proteins into nuclear aggregates.

    Science.gov (United States)

    Hübner, S; Eam, J E; Hübner, A; Jans, D A

    2006-01-15

    Lamins, members of the family of intermediate filaments, form a supportive nucleoskeletal structure underlying the nuclear envelope and can also form intranuclear structures. Mutations within the A-type lamin gene cause a variety of degenerative diseases which are collectively referred to as laminopathies. At the molecular level, laminopathies have been shown to be linked to a discontinuous localization pattern of A-type lamins, with some laminopathies containing nuclear lamin A aggregates. Since nuclear aggregate formation could lead to the mislocalization of proteins interacting with A-type lamins, we set out to examine the effects of FLAG-lamin A N195K and R386K protein aggregate formation on the subnuclear distribution of the retinoblastoma protein (pRb) and the sterol responsive element binding protein 1a (SREBP1a) after coexpression as GFP-fusion proteins in HeLa cells. We observed strong recruitment of both proteins into nuclear aggregates. Nuclear aggregate recruitment of the NPC component nucleoporin NUP153 was also observed and found to be dependent on the N-terminus. That these effects were specific was implied by the fact that a number of other coexpressed karyophilic GFP-fusion proteins, such as the nucleoporin NUP98 and kanadaptin, did not coaggregate with FLAG-lamin A N195K or R386K. Immunofluorescence analysis further indicated that the precursor form of lamin A, pre-lamin A, could be found in intranuclear aggregates. Our results imply that redistribution into lamin A-/pre-lamin A-containing aggregates of proteins such as pRb and SREBP1a could represent a key aspect underlying the molecular pathogenesis of certain laminopathies.

  18. The Nuclear Shape Phase Transitions Studied within the Geometric Collective Model

    Directory of Open Access Journals (Sweden)

    Khalaf A. M.

    2013-04-01

    Full Text Available In the framework of the Geometric Collective Model (GCM, quantum phase transition between spherical and deformed shapes of doubly even nuclei are investigated. The validity of the model is examined for the case of lanthanide chains Nd / Sm and actinide chains Th / U. The parameters of the model were obtained by performing a computer simulated search program in order to obtain minimum root mean square deviations be- tween the calculated and the experimental excitation energies. Calculated potential en- ergy surfaces (PES’s describing all deformation effects of each nucleus are extracted. Our systematic studies on lanthanide and actinide chains have revealed a shape transi- tion from spherical vibrator to axially deformed rotor when moving from the lighter to the heavier isotopes.

  19. Nuclear energy. The post-Fukushima situation, debate about the French exception, the energy transition; Nucleaire. La situation apres Fukushima, debat sur l'exception francaise, la transition energetique

    Energy Technology Data Exchange (ETDEWEB)

    Bezat, J.M.; Tazieff, H.; Morin, H.; Le Hir, P.; Vincent, C.; Labbe, M.H.; Viansson-Ponte, P.; Saint-James, D.; Tatu, M.; Pons, P.; Kempf, H.; Lemaitre, F.; Baudet, M.B.; Armagnac, B. d' ; Allix, G.; Foucart, S.; Barroux, R. [Le Monde, 80 boulevard Auguste Blanqui, 75707 Paris Cedex 13 (France)

    2011-12-15

    Published 8 months after the Fukushima Dai-ichi accident, this special issue of Le Monde newspaper takes stock of the nuclear question. Prior to the Fukushima accident, the civil nuclear industry experienced two other major accidents: Three Miles Island (US, 1979) with limited and controlled impacts, and Chernobyl (USSR, 1986) with enormous impacts. The recent Japanese catastrophe has revived the questions concerning this risky technology. However, according to the IAEA, the civil nuclear energy should continue to develop in the future but in a more moderate way. Germany announced in June 2011 the shutdown of its last reactor by 2022, while France remained an exception until the Fukushima accident with a large political consensus among the general public in favor of nuclear energy. The nuclear phasing out or the energy transition is a complex question which is explored in this special issue. Content: 1 - The nuclear world: a moderate growth of the nuclear industry; interview of Mohamed ElBaradei, former head of IAEA; 441 reactors in operation in the world in January 2011; France has chosen the all-nuclear option; critics: a 'costly, unadapted, useless' nuclear program; interview of Valery Giscard d'Estaing, former French President; the nuclear industry actors; nuclear dismantling: a what cost?; how to manage the 250.000 tons of spent fuels; 2 - A risky technology: radioactivity measurement and effects; how to manage contaminations; four generations of reactors; ITER: a solar project; imagining the unimaginable and anticipating the worse; the wake up of a dozed off fear; the most important accidents: the progress of the three main nuclear catastrophes, the human mistake of Three Mile Island, the days after the Chernobyl accident, in the dead cities around Fukushima; interview of Kenzaburo Oe (Japanese writer); the Blayais power plant to the test; 3 - The energy transition: is France capable to abandon nuclear energy?; Germany is going to re-launch gas

  20. Role of nuclear receptor CAR in carbon tetrachloride-induced hepatotoxicity

    Institute of Scientific and Technical Information of China (English)

    Yuichi Yamazaki; Satoru Kakizaki; Norio Horiguchi; Hitoshi Takagi; Masatomo Mori; Masahiko Negishi

    2005-01-01

    AIM: To investigate the precise roles of CAR in CCl4-induced acute hepatotoxicity.METHODS: To prepare an acute liver injury model, CCl4 was intraperitoneally injected in CAR+/+ and CAR-/- mice.RESULTS: Elevation of serum alanine aminotransferase and extension of centrilobular necrosis were slightly inhibited in CAR-/- mice compared to CAR+/+ mice without PB. Administration of a CAR inducer, PB, revealed that CCl4-induced liver toxicity was partially inhibited in CAR-/- mice compared with CAR+/+ mice. On the other hand,androstanol, an inverse agonist ligand, inhibited hepatotoxicity in CAR+/+ but not in CAR-/- mice. Thus, CAR activation caused CCl4 hepatotoxicity while CAR inhibition resulted in partial protection against CCl4-induced hepatotoxicity.There were no differences in the expression of CYP2E1, the main metabolizing enzyme for CCl4, between CAR+/+ and CAR-/- mice. However, the expression of other CCl4-metabolizing enzymes, such as CYP2B10 and 3A11, was induced by PB in CAR+/+ but not in CAR-/- mice. Although the main pathway of CCl4-induced acute liver injury is mediated by CYP2E1, CAR modulates its pathway via induction of CYP2B10 and 3A11 in the presence of activator or inhibitor.CONCLUSION: The nuclear receptor CAR modulates CCl4-induced liver injury via induction of CCl4-metabolizing enzymes in the presence of an activator. Our results suggest that drugs interacting with nuclear receptors such as PB might play critical roles in drug-induced liver injury or drugdrug interaction even though such drugs themselves are not hepatotoxic.

  1. Induced rotation from de Sitter-Godel-de Sitter phase transition

    CERN Document Server

    Khodabakhshi, Sh

    2016-01-01

    The rotation of the cosmic objects is a universal phenomenon and its origin is still an open question. Here a model for the origin of rotation is presented. After an investigation of the phase transition of a scalar field in de Sitter and G\\"odel backgrounds, the motion of a test particle during the phase transitions is studied. Then using computer simulation for a congruence of particles, we show that although the local induced rotation is nonzero, the global rotation is below the observational limit.

  2. Paraelectric-ferroelectric interface dynamics induced by latent heat transfer and irreversibility of ferroelectric phase transitions

    Institute of Scientific and Technical Information of China (English)

    Ai Shu-Tao

    2006-01-01

    The temperature gradients that arise in the paraelectric-ferroelectric interface dynamics induced by the latent heat transfer are studied from the point of view that a ferroelectric phase transition is a stationary, thermal-electric coupled transport process. The local entropy production is derived for a ferroelectric phase transition system from the Gibbs equation. Three types of regions in the system are described well by using the Onsager relations and the principle of minimum entropy production. The theoretical results coincides with the experimental ones.

  3. Cascade of magnetic field induced spin transitions in LaCoO3.

    Science.gov (United States)

    Altarawneh, M M; Chern, G-W; Harrison, N; Batista, C D; Uchida, A; Jaime, M; Rickel, D G; Crooker, S A; Mielke, C H; Betts, J B; Mitchell, J F; Hoch, M J R

    2012-07-20

    We present magnetization and magnetostriction studies of LaCoO3 in magnetic fields approaching 100 T. In contrast with expectations from single-ion models, the data reveal two distinct first-order transitions and well-defined magnetization plateaus. The magnetization at the higher plateau is only about half the saturation value expected for spin-1 Co3+ ions. These findings strongly suggest collective behavior induced by interactions between different electronic configurations of Co3+ ions. We propose a model that predicts crystalline spin textures and a cascade of four magnetic phase transitions at high fields, of which the first two account for the experimental data.

  4. Noise-Induced Phase Transition: Zero-Dimensional Brownian Particles Varying between Ergodicity and Nonergodicity

    Institute of Scientific and Technical Information of China (English)

    BAI Zhan-Wu

    2008-01-01

    @@ We study in phase space a zero-dimensional system of Brownian particles which move in a periodic potential and subject to an internal time derivative Ornstein-Uhlenbeck noise. To resolve the Fokker-Planck equation in such a case, we propose an approximate analytical method. The theoretical predictions exhibit a second order noise-induced nonequilibrium phase transition, which is confirmed by numerical simulation results. The phase transition brings the system from an ergodicity to a nonergodicity phase as the potential barrier height decreases.

  5. Magnetostrictive hypersound generation by spiral magnets in the vicinity of magnetic field induced phase transition

    Energy Technology Data Exchange (ETDEWEB)

    Bychkov, Igor V. [Chelyabinsk State University, 129 Br. Kashirinykh Str., Chelyabinsk 454001 (Russian Federation); South Ural State University (National Research University), 76 Lenin Prospekt, Chelyabinsk 454080 (Russian Federation); Kuzmin, Dmitry A., E-mail: kuzminda@csu.ru [Chelyabinsk State University, 129 Br. Kashirinykh Str., Chelyabinsk 454001 (Russian Federation); South Ural State University (National Research University), 76 Lenin Prospekt, Chelyabinsk 454080 (Russian Federation); Kamantsev, Alexander P.; Koledov, Victor V.; Shavrov, Vladimir G. [Kotelnikov Institute of Radio-engineering and Electronics of RAS, Mokhovaya Street 11-7, Moscow 125009 (Russian Federation)

    2016-11-01

    In present work we have investigated magnetostrictive ultrasound generation by spiral magnets in the vicinity of magnetic field induced phase transition from spiral to collinear state. We found that such magnets may generate transverse sound waves with the wavelength equal to the spiral period. We have examined two types of spiral magnetic structures: with inhomogeneous exchange and Dzyaloshinskii–Moriya interactions. Frequency of the waves from exchange-caused spiral magnetic structure may reach some THz, while in case of Dzyaloshinskii–Moriya interaction-caused spiral it may reach some GHz. These waves will be emitted like a sound pulses. Amplitude of the waves is strictly depends on the phase transition speed. Some aspects of microwaves to hypersound transformation by spiral magnets in the vicinity of phase transition have been investigated as well. Results of the work may be interesting for investigation of phase transition kinetics as well, as for various hypersound applications. - Highlights: • Magnetostrictive ultrasound generation by spiral magnets at phase transition (PT) is studied. • Spiral magnets during PT may generate transverse sound with wavelength equal to spiral period. • Amplitude of the sound is strictly depends on the phase transition speed. • Microwave-to-sound transformation in the vicinity of PT is investigated as well.

  6. Pressure-induced conformation transition of o-phenylene solvated in bulk hydrocarbons.

    Science.gov (United States)

    Riello, Massimo; Doni, Giovanni; Filip, Sorin V; Gold, Martin; De Vita, Alessandro

    2014-11-26

    The conformational behavior of o-phenylene 8-mers and 10-mers solvated in a series of linear alkane solvents by means of classical molecular dynamics and first-principles calculations was studied. Irrespective of the solvent used, we find that at ambient pressure the molecule sits in the well-defined close-helical arrangement previously observed in light polar solvents. However, for pressures greater than 50 atm, and for tetradecane or larger solvent molecules, our simulations predict that o-phenylene undergoes a conformational transition to an uncoiled, extended geometry with a 35% longer head-to-tail distance and a much larger overlap between its lateral aromatic ring groups. The free energy barrier for the transition was studied as a function of pressure and temperature for both solute molecules in butane and hexadecane. Gas-phase density functional theory-based nudged elastic band calculations on 8-mer and 10-mer o-phenylene were used to estimate how the pressure-induced transition energy barrier changes with solute length. Our results indicate that a sufficiently large solvent molecule size is the key factor enabling a configuration transition upon pressure changes and that longer solute molecules associate with higher conformation transition energy barriers. This suggests the possibility of designing systems in which a solute molecule can be selectively "activated" by a controlled conformation transition achieved at a predefined set of pressure and temperature conditions.

  7. Magnetic field induced 1st order transitions: Recent studies, and some new concepts

    Science.gov (United States)

    Chaddah, P.

    2015-05-01

    Phase transitions are caused by varying temperature, or pressure, or magnetic field. The observation of 1st order magneto-structural transitions has created application possibilities based on magnetoresistance, magnetocaloric effect, magnetic shape memory effect, and magneto-dielectric effect. Magnetic field induced transitions, and phase coexistence of competing magnetic phases down to the lowest temperature, gained prominence over a decade ago with theoretical models suggesting that the ground state is not homogeneous. Researchers at Indore pushed an alternative view that this phase coexistence could be due to glasslike "kinetic arrest" of a disorder-broadened first-order magnetic transition between two states with long-range magnetic order, resulting in phase coexistence down to the lowest temperatures. The CHUF (cooling and heating in unequal field) protocol created at Indore allows the observation of `devitrification', followed by `melting'. I show examples of measurements establishing kinetic arrest in various materials, emphasizing that glasslike arrest of 1st order magnetic transitions may be as ubiquitous as glass formation following the arrest of 1st order structural transitions.

  8. Analysis of probabilities for nuclear excitation by near-resonant electronic transitions

    CERN Document Server

    Harston, M R

    2001-01-01

    Theoretical results are presented for nuclear excitation of low-lying isometric states of sup 1 sup 9 sup 7 Au, sup 1 sup 8 sup 9 Os and sup 2 sup 3 sup 7 Np by a near-resonant electronic deexcitation process known as NEET. A detailed comparison is made between current and previous theoretical results in order to clarify a number of anomalies. For sup 1 sup 9 sup 7 Au, the only case in which the current experimental precision appears to be sufficient to provide a stringent test of theory, the theoretical result for the NEET probability is P sub N sub E sub E sub T =3.6x10 sup - sup 8. This is a factor of three lower than previous theoretical results and reduces the difference between theory and the recent experimental result, P sub N sub E sub E sub T =(5.0+-0.6)x10 sup - sup 8 , to a level of approximately 2 sigma.

  9. Performance impact on nuclear thermal propulsion of piloted Mars missions with short transit times

    Science.gov (United States)

    Wickenheiser, T. J.; Gessner, K. S.; Alexander, S. W.

    1991-01-01

    The requirements of nuclear thermal propulsion (NTP) are examined with respect to a specific mission scenario derived from Stafford Committee recommendations. The recommended mission scenario is a split/sprint opposition mission which includes a piloted vehicle and a cargo vehicle, and the baseline mission is developed from a reference trajectory. Key mision parameters are developed from the baseline mission, including engine-thrust levels, mission opportunity, and engine burn-time requirements. The impact of engine failure is also considered in terms of burn-time requirements, and other mission-performance issues considered include propulsion-technology assumptions, triple-perigee earth-departure burns, and Mars parking-orbit selection. The engine requirements call for a 50-75-klb engine-thrust level, maximum single burn time of 0.6 hours, and a maximum total-mission burn time of 1.7 hours. For a crew of 6, a 475-day total-mission trip with a 90-day stay at Mars is possible.

  10. Proteomic analysis of nuclear matrix proteins during arsenic trioxide induced apoptosis in leukemia K562 cells

    Institute of Scientific and Technical Information of China (English)

    WANG Zi-hui; YU Ding; CHEN Yan; HAO Jian-zhong

    2005-01-01

    Background Arsenic trioxide (As2O3) has been identified as a very potent anti-acute leukemic agent. However its role in apoptosis needs to be elucidated. As2O3 interferes with the proliferation and survival of tumor cells via a variety of mechanisms. Drug-target interactions at the level of nuclear matrix (NM) may be critical events in the induction of cell death by As2O3. This study dealt with As2O3-target interactions at the level of NM in chronic myelogenous leukemia cell line K562 by proteomics. Methods K562 cells were cultured in MEM and treated with different concentrations of As2O3. The nuclear matrix proteins were analyzed by high-resolution two-dimensional gel electrophoresis and computer-assisted image analysis. Results As2O3 significantly inhibited the growth of chronic myelogenous leukemia cell line K562 at low concentrations. While more than 200 protein spots were shared among the nuclear matrices, about 18 distinct spots in the nuclear matrices were found characteristic for As2O3 treated cells. Conclusions: As2O3 induces apoptosis in K562 cells in a dose and time-dependent manner. Our results demonstrated that for the detection of the onset of apoptosis, the alteration in the composition of nuclear matrix proteins was a more sensitive indicator than nucleosomal DNA fragmentation test. These results indicated that As2O3 might be clinically useful in the treatment of chronic myelogenous leukemia. The changes of nuclear matrix proteins in the treated cells can be used as a useful indicator for this treatment.

  11. Theoretical direct WIMP detection rates for transitions to nuclear excited states

    CERN Document Server

    Vergados, J D; Pirinen, P; Srivastava, P C; Kortelainen, M; Suhonen, J

    2015-01-01

    The recent WMAP and Planck data have confirmed that exotic dark matter together with the vacuum energy (cosmological constant) dominate in the flat Universe. Many extensions of the standard model provide dark matter candidates, in particular Weakly Interacting Massive Particles (WIMPs). Thus the direct dark matter detection is central to particle physics and cosmology. Most of the research on this issue has hitherto focused on the detection of the recoiling nucleus. In this paper we study transitions to the excited states, possible in some nuclei, which have sufficiently low lying excited states. Examples considered previously were the first excited states of $^{127}$I and $^{129}$Xe. We examine here $^{83}$Kr, which offers some kinematical advantages and is currently considered as a possible target. We find appreciable branching ratios for the inelastic scattering mediated by the spin cross sections, with an inelastic event rate of $4.4\\times 10^{-4}$kg$^{-1}$d$^{-1}$. So, the extra signature of the gamma ra...

  12. Nuclear two-photon decay in 0/sup +/ -> 0/sup +/ transitions

    Energy Technology Data Exchange (ETDEWEB)

    Kramp, J.; Habs, D.; Kroth, R.; Music, M.; Schirmer, J.; Schwalm, D.; Broude, C.

    1987-11-23

    The two-photon decay of the first excited 0/sup +/ state of /sup 16/O has been measured using the Heidelberg-Darmstadt crystal ball. A branching ratio of GAMMA/sub ..gamma gamma..//GAMMA/sub tot/ = (6.6+-0.5).10/sup -4/ was obtained. As in the cases of /sup 40/Ca and /sup 90/Zr previously reported by us, the 2..gamma.. decay of /sup 16/O proceeds via double E1 and M1 transitions of similar strength; the evidence is the observed interference term in the 2..gamma.. angular correlation. The ratio of the matrix elements ..cap alpha../sub E1//chi for /sup 16/O was restricted to the two inverse values (-6.2+-1.5) or (-0.16+-0.04). An interpretation of 2..gamma.. matrix elements observed for /sup 16/O, /sup 40/Ca and /sup 90/Zr in terms of the electric polarizabilities and magnetic susceptibility is given leading to a qualitative understanding of this decay mode.

  13. Toll-like receptor 4 signaling promotes epithelial-mesenchymal transition in human hepatocellular carcinoma induced by lipopolysaccharide

    Directory of Open Access Journals (Sweden)

    Jing Ying-Ying

    2012-08-01

    Full Text Available Abstract Background The endotoxin level in the portal and peripheral veins of hepatocellular carcinoma (HCC patients is higher and lipopolysaccharide (LPS, a cell wall constituent of gram-negative bacteria, has been reported to inhibit tumor growth. However, in this study, we found that LPS-induced toll-like receptor 4 (TLR4 signaling was involved in tumor invasion and survival, and the molecular mechanism was investigated, Methods Four HCC cell lines and a splenic vein metastasis of the nude mouse model were used to study the invasion ability of LPS-induced HCC cells and the epithelia-mesenchymal transition (EMT in vitro and in vivo. A total of 106 clinical samples from HCC patients were used to evaluate TLR4 expression and analyze its association with clinicopathological characteristics Results The in vitro and in vivo experiments demonstrated that LPS could significantly enhance the invasive potential and induce EMT in HCC cells with TLR4 dependent. Further studies showed that LPS could directly activate nuclear factor kappa B (NF-κB signaling through TLR4 in HCC cells. Interestingly, blocking NF-κB signaling significantly inhibited transcription factor Snail expression and thereby inhibited EMT occurrence. High expression of TLR4 in HCC tissues was strongly associated with both poor cancer-free survival and overall survival in patients. Conclusions Our results indicate that TLR4 signaling is required for LPS-induced EMT, tumor cell invasion and metastasis, which provide molecular insights for LPS-related pathogenesis and a basis for developing new strategies against metastasis in HCC.

  14. Cold exposure rapidly induces virtual saturation of brown adipose tissue nuclear T sub 3 receptors

    Energy Technology Data Exchange (ETDEWEB)

    Bianco, A.C.; Silva, J.E. (Univ. of Sao Paulo (Brazil) Harvard Medical School, Boston, MA (USA))

    1988-10-01

    Cold exposure induces a rapid increase in uncoupling protein (UCP) concentration in the brown adipose tissue (BAT) of euthyroid, but not hypothyroid, rats. To normalize this response with exogenous 3,5,3{prime}-triiodothyronine (T{sub 3}), it is necessary to cause systemic hyperthyroidism. In contrast, the same result can be obtained with just replacement doses of thyroxine (T{sub 4}) and, in euthyroid rats, the normal response of UCP to cold occurs without hyperthyroid plasma T{sub 3} levels. Consequently, the authors explored the possibility that the cold-induced activation of the type II 5{prime}-deiodinase resulted in high levels of nuclear T{sub 3} receptor occupancy in euthyroid rats. Studies were performed with pulse injections of tracer T{sub 3} or T{sub 4} in rats exposed to 4{degree}C for different lengths of time (1 h-3 wk). Within 4 h of cold exposure, they observed a significant increase in the nuclear ({sup 125}I)T{sub 3} derived from the tracer ({sup 125}I)T{sub 4} injections (T{sub 3}(T{sub 4})) and a significant reduction in the nuclear ({sup 125}I)T{sub 3} derived from ({sup 125}I)T{sub 3} injections (T{sub 3}(T{sub 3})). The number of BAT nuclear T{sub 3} receptors did not increase for up to 3 wk of observation at 4{degree}C. The mass of nuclear-bound T{sub 3} was calculated from the nuclear tracer ({sup 125}I)T{sub 3}(T{sub 3}) and ({sup 125}I)T{sub 3}(T{sub 4}) at equilibrium and the specific activity of serum T{sub 3} and T{sub 4}, respectively. By 4 h after the initiation of the cold exposure, the receptors were >95% occupied and remained so for the 3 weeks of observation. They conclude that the simultaneous activation of the deiodinase with adrenergic BAT stimulation serves the purpose of nearly saturating the nuclear T{sub 3} receptors. This makes possible the realization of the full thermogenic potential of the tissue without causing systemic hyperthyroidism.

  15. Improved limit on the induced scalar interaction in nuclear. beta. -decay

    Energy Technology Data Exchange (ETDEWEB)

    Szybisz, L.; Silbergleit, V.M.

    1981-01-01

    An improved procedure which allows to diminish by almost a factor 2 the upper limit on the induced scalar interaction obtained from a study of superallowed Fermi ..beta..-transitions is reported. The new limit, fsub(S) <= 0.6 x 10/sup -3/ < fsub(M) = 1.0 x 10/sup -3/, supports the CVC theory and the invariance of weak interactions under G-parity transformation.

  16. The overexpression of nuclear envelope protein Lap2β induces endoplasmic reticulum reorganisation via membrane stacking

    Directory of Open Access Journals (Sweden)

    Ekaterina G. Volkova

    2012-06-01

    Some nuclear envelope proteins are localised to both the nuclear envelope and the endoplasmic reticulum; therefore, it seems plausible that even small amounts of these proteins can influence the organisation of the endoplasmic reticulum. A simple method to study the possible effects of nuclear envelope proteins on endoplasmic reticulum organisation is to analyze nuclear envelope protein overexpression. Here, we demonstrate that Lap2β overexpression can induce the formation of cytoplasmic vesicular structures derived from endoplasmic reticulum membranes. Correlative light and electron microscopy demonstrated that these vesicular structures were composed of a series of closely apposed membranes that were frequently arranged in a circular fashion. Although stacked endoplasmic reticulum cisternae were highly ordered, Lap2β could readily diffuse into and out of these structures into the surrounding reticulum. It appears that low-affinity interactions between cytoplasmic domains of Lap2β can reorganise reticular endoplasmic reticulum into stacked cisternae. Although the effect of one protein may be insignificant at low concentrations, the cumulative effect of many non-specialised proteins may be significant.

  17. Erosion/Corrosion-Induced Pipe Wall Thinning in U.S. Nuclear Power Plants

    Energy Technology Data Exchange (ETDEWEB)

    Wu, P. C. [US Nuclear Regulatory Commission (NRC), Washington, DC (United States). Division of Engineering and Systems Technology

    1989-04-01

    Erosion/corrosion in single-phase piping systems was not clearly recognized as a potential safety issue before the pipe rupture incident at the Surry Power Station in December 1986. This incident reminded the nuclear industry and the regulators that neither the U.S. Nuclear Regulatory Commission (NRC) nor Section XI of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code require utilities to monitor erosion/corrosion in the secondary systems of nuclear power plants. This report provides a brief review of the erosion/corrosion phenomenon and its major occurrences in nuclear power plants. In addition, efforts by the NRC, the industry, and the ASME Section XI Committee to address this issue are described. Finally, results of the survey and plant audits conducted by the NRC to assess the extent of erosion/corrosion-induced piping degradation and the status of program implementation regarding erosion/corrosion monitoring are discussed. This report will support a staff recommendation for an additional regulatory requirement concerning erosion/corrosion monitoring.

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

    Science.gov (United States)

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

    2014-09-01

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

  19. Pressure Induced Polymorphic Phase Transition of Natural Metamorphic Kalsilite; Electrical Resistivity and Infrared Spectroscopic Investigations

    Directory of Open Access Journals (Sweden)

    G. Parthasarathy

    2015-10-01

    Full Text Available We report here pressure dependence of the electrical resistivity of natural kalsilite (K0.998Na0.002Al0.998Fe0.002SiO4 from a granulite facies terrain in southern India. The electrical resistivity of kalsilite was measured with four probe technique up to 7.5 GPa at room temperature. The electrical resistivity decreases continuously with the increase of pressure up to 3.7 GPa, where there is a discontinuous drop in the electrical resistivity by 14%–16% indicating a first order transition. Further increase of pressure does not induce any phase transition up to 7.5 GPa at room temperature. Fourier transform infrared (FTIR spectroscopy of the kalsilite sample at various pressures indicates that the observed transition is reversible in nature.

  20. Pressure-induced phase transition in wurtzite ZnTe: an ab initio study.

    Science.gov (United States)

    Alptekin, Sebahaddin

    2012-03-01

    A constant pressure ab initio MD technique and density functional theory with a generalized gradient approximation (GGA) was used to study the pressure-induced phase transition in wurtzite ZnTe. A first-order phase transition from the wurtzite structure to a Cmcm structure was successfully observed in a constant-pressure molecular dynamics simulation. This phase transformation was also analyzed using enthalpy calculations. We also investigated the stability of wurtzite (WZ) and zinc-blende (ZB) phases from energy-volume calculations, and found that both structures show quite similar equations of state and transform into a Cmcm structure at 16 GPa using enthalpy calculations, in agreement with experimental observations. The transition phase, lattice parameters and bulk properties we obtained are comparable with experimental and theoretical data.

  1. Signatures of a pressure-induced topological quantum phase transition in BiTeI.

    Science.gov (United States)

    Xi, Xiaoxiang; Ma, Chunli; Liu, Zhenxian; Chen, Zhiqiang; Ku, Wei; Berger, H; Martin, C; Tanner, D B; Carr, G L

    2013-10-11

    We report the observation of two signatures of a pressure-induced topological quantum phase transition in the polar semiconductor BiTeI using x-ray powder diffraction and infrared spectroscopy. The x-ray data confirm that BiTeI remains in its ambient-pressure structure up to 8 GPa. The lattice parameter ratio c/a shows a minimum between 2.0-2.9 GPa, indicating an enhanced c-axis bonding through p(z) band crossing as expected during the transition. Over the same pressure range, the infrared spectra reveal a maximum in the optical spectral weight of the charge carriers, reflecting the closing and reopening of the semiconducting band gap. Both of these features are characteristics of a topological quantum phase transition and are consistent with a recent theoretical proposal.

  2. Resolution of hyperfine transitions in metastable 83Kr using Electromagnetically Induced Transparency

    CERN Document Server

    Kale, Y B; Tiwari, V B; Singh, S; Rawat, H S

    2015-01-01

    Narrow linewidth signals of Electromagnetically Induced Transparency (EIT) in the metastable 83Kr have been observed for the first time. Various hyperfine transitions in 4p55s[3/2]2 to 4p55p[5/2]3 manifolds of 83Kr have been identified through the experimentally observed EIT signals. Some unresolved or poorly resolved hyperfine transitions in saturated absorption spectroscopy (SAS) are clearly resolved in the present work. Using the spectral separation of these EIT identified hyperfine transitions, the magnetic hyperfine constant (A) and the electric quadrupole hyperfine constant (B) are determined with improved accuracy for 4p55s[3/2]2 and 4p55p[5/2]3 manifolds.

  3. A boundary field induced first-order transition in the 2D Ising model: numerical study

    Energy Technology Data Exchange (ETDEWEB)

    Bittner, Elmar; Janke, Wolfhard [Institut fuer Theoretische Physik and Centre for Theoretical Sciences (NTZ), Universitaet Leipzig, Postfach 100 920, D-04009 Leipzig (Germany)], E-mail: elmar.bittner@itp.uni-leipzig.de, E-mail: Wolfhard.janke@itp.uni-leipzig.de

    2008-10-03

    In a recent paper, Clusel and Fortin (2006 J. Phys. A: Math. Gen. 39 995) presented an analytical study of a first-order transition induced by an inhomogeneous boundary magnetic field in the two-dimensional Ising model. They identified the transition that separates the regime where the interface is localized near the boundary from that where it propagates inside the bulk. Inspired by these results, we measured the interface tension by using multimagnetic simulations combined with parallel tempering to determine the phase transition and the location of the interface. Our results are in very good agreement with the theoretical predictions. Furthermore, we studied the spin-spin correlation function for which no analytical results are available.

  4. Transcriptional Profile of HIV-induced Nuclear Translocation of Amyloid β in Brain Endothelial Cells

    Science.gov (United States)

    András, Ibolya E.; Rampersaud, Evadnie; Eum, Sung Yong; Toborek, Michal

    2015-01-01

    Background and Aims Increased amyloid deposition in HIV-infected brains may contribute to the pathogenesis of neurocognitive dysfunction in infected patients. We have previously shown that exposure to HIV results in enhanced amyloid β (Aβ) levels in human brain microvascular endothelial cells, suggesting that brain endothelial cells contribute to accumulation of Aβ in HIV-infected brains. Importantly, Aβ not only accumulates in the cytoplasm of HIV-exposed cells but also enters the nuclei of brain endothelial cells. Methods cDNA microarray analysis was performed in order to examine changes in the transcriptional profile associated with Aβ nuclear entry in the presence of HIV-1. Results Gene network analysis indicated that inhibition of nuclear entry of Aβ resulted in enrichment in gene sets involved in apoptosis and survival, endoplasmic reticulum stress response, immune response, cell cycle, DNA damage, oxidative stress, cytoskeleton remodeling and transforming growth factor b (TGFβ) receptor signaling. Conclusions The obtained data indicate that HIV-inducednuclear uptake affects several cellular stress-related pathways relevant for HIV-induced Aβ pathology. PMID:25446617

  5. Spike-timing-dependent plasticity enhanced synchronization transitions induced by autapses in adaptive Newman-Watts neuronal networks.

    Science.gov (United States)

    Gong, Yubing; Wang, Baoying; Xie, Huijuan

    2016-12-01

    In this paper, we numerically study the effect of spike-timing-dependent plasticity (STDP) on synchronization transitions induced by autaptic activity in adaptive Newman-Watts Hodgkin-Huxley neuron networks. It is found that synchronization transitions induced by autaptic delay vary with the adjusting rate Ap of STDP and become strongest at a certain Ap value, and the Ap value increases when network randomness or network size increases. It is also found that the synchronization transitions induced by autaptic delay become strongest at a certain network randomness and network size, and the values increase and related synchronization transitions are enhanced when Ap increases. These results show that there is optimal STDP that can enhance the synchronization transitions induced by autaptic delay in the adaptive neuronal networks. These findings provide a new insight into the roles of STDP and autapses for the information transmission in neural systems. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  6. Recombination of charge carriers on radiation-induced defects in silicon doped by transition metals impurities

    CERN Document Server

    Kazakevich, L A

    2003-01-01

    It has been studied the peculiarities of recombination of nonequilibrium charge carriers on radiation-induced defects in received according to Czochralski method p-silicon (p approx 3 - 20 Ohm centre dot cm), doped by one of the impurities of transition metals of the IV-th group of periodic table (titanium, zirconium, hafnium). Experimental results are obtained out of the analysis of temperature and injection dependence of the life time of charge carriers. The results are explained taking into consideration the influences of elastic stress fields created by the aggregates of transition metals atoms on space distribution over the crystal of oxygen and carbon background impurities as well as on the migration of movable radiation-induced defects during irradiation. (authors).

  7. Quantum Oscillation Signatures of Pressure-induced Topological Phase Transition in BiTeI.

    Science.gov (United States)

    Park, Joonbum; Jin, Kyung-Hwan; Jo, Y J; Choi, E S; Kang, W; Kampert, E; Rhyee, J-S; Jhi, Seung-Hoon; Kim, Jun Sung

    2015-11-02

    We report the pressure-induced topological quantum phase transition of BiTeI single crystals using Shubnikov-de Haas oscillations of bulk Fermi surfaces. The sizes of the inner and the outer FSs of the Rashba-split bands exhibit opposite pressure dependence up to P = 3.35 GPa, indicating pressure-tunable Rashba effect. Above a critical pressure P ~ 2 GPa, the Shubnikov-de Haas frequency for the inner Fermi surface increases unusually with pressure, and the Shubnikov-de Haas oscillations for the outer Fermi surface shows an abrupt phase shift. In comparison with band structure calculations, we find that these unusual behaviors originate from the Fermi surface shape change due to pressure-induced band inversion. These results clearly demonstrate that the topological quantum phase transition is intimately tied to the shape of bulk Fermi surfaces enclosing the time-reversal invariant momenta with band inversion.

  8. Pressure-induced iso-structural phase transition and metallization in WSe2

    Science.gov (United States)

    Wang, Xuefei; Chen, Xuliang; Zhou, Yonghui; Park, Changyong; An, Chao; Zhou, Ying; Zhang, Ranran; Gu, Chuanchuan; Yang, Wenge; Yang, Zhaorong

    2017-05-01

    We present in situ high-pressure synchrotron X-ray diffraction (XRD) and Raman spectroscopy study, and electrical transport measurement of single crystal WSe2 in diamond anvil cells with pressures up to 54.0-62.8 GPa. The XRD and Raman results show that the phase undergoes a pressure-induced iso-structural transition via layer sliding, beginning at 28.5 GPa and not being completed up to around 60 GPa. The Raman data also reveals a dominant role of the in-plane strain over the out-of plane compression in helping achieve the transition. Consistently, the electrical transport experiments down to 1.8 K reveals a pressure-induced metallization for WSe2 through a broad pressure range of 28.2-61.7 GPa, where a mixed semiconducting and metallic feature is observed due to the coexisting low- and high-pressure structures.

  9. Noise-Induced Transitions in a Population Growth Model Based on Size-Dependent Carrying Capacity

    Directory of Open Access Journals (Sweden)

    Neeme Lumi

    2014-01-01

    Full Text Available The stochastic dynamics of a population growth model with size-dependent carrying capacity is considered. The effect of a fluctuating environment on population growth is modeled as a multiplicative dichotomous noise. At intermediate values of population size the deterministic counterpart of the model behaves similarly to the Von Foerster model for human population, but at small and very large values of population size substantial differences occur. In the stochastic case, an exact analytical solution for the stationary probability distribution is found. It is established that variation of noise correlation time can cause noise-induced transitions between three different states of the system characterized by qualitatively different behaviors of the probability distributions of the population size. Also, it is shown that, in some regions of the system parameters, variation of the amplitude of environmental fluctuations can induce single unidirectional abrupt transitions of the mean population size.

  10. Calcium-Mediated Mitochondrial Permeability Transition Involved in Hydrogen Peroxide-Induced Apoptosis in Tobacco Protoplasts

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    In the present study, we focused on whether intracellular free Ca2+ ([Ca2+]i) regulates the formation of mitochondrial permeability transition pore (MPTP) in H2O2-induced apoptosis in tobacco protoplasts. It was shown that the decrease in mitochondrial membrane potential (△Ψm) preceded the appearance of H2O2-induced apoptosis;pretreatment with the specific MPTP inhibitor cyclosporine A, which also inhibits Ca2+ cycling by the mitochondria,effectively retarded apoptosis and the decrease in △Ψm. Apoptosis and decreased △Ψm were exacerbated by CaCl2, whereas the plasma membrane voltage-dependent Ca2+ channel blocker lanthanum chloride (LaCl3)attentuated these responses. Chelation of extracellular Ca2+ with EGTA almost totally inhibited apoptosis and the decrease in △Ψm induced by H2O2. The time-course of changes in [Ca2+]i in apoptosis was detected using the Ca2+ probe Fluo-3 AM. These studies showed that [Ca2+]i was increased at the very early stage of H2O2-induced apoptosis. The EGTA evidently inhibited the increase in [Ca2+]i induced by H2O2, whereas it was only partially inhibited by LaCl3. The results suggest that H2O2 may elevate cytoplasmic free Ca2+ concentrations in tobacco protoplasts, which mainly results from the entry of extracellular Ca2+, to regulate mitochondrial permeability transition. The signaling pathway of [Ca2+]i-mediated mitochondrial permeability transition was associated with H2O2-induced apoptosis in tobacco protoplasts.

  11. Pulse and quench induced dynamical phase transition in a chiral multiferroic spin chain

    Science.gov (United States)

    Azimi, M.; Sekania, M.; Mishra, S. K.; Chotorlishvili, L.; Toklikishvili, Z.; Berakdar, J.

    2016-08-01

    Quantum dynamics of magnetic order in a chiral multiferroic chain is studied. We consider two different scenarios: ultrashort terahertz excitations or a sudden electric field quench. Performing analytical and numerical exact diagonalization calculations, we trace the pulse induced spin dynamics and extract quantities that are relevant to quantum information processing. In particular, we analyze the dynamics of the system chirality, the von Neumann entropy, and the pairwise and many-body entanglement. If the characteristic frequencies of the generated states are noncommensurate, then a partial loss of pair concurrence occurs. Increasing the system size, this effect becomes even more pronounced. Many-particle entanglement and chirality are robust and persist in the incommensurate phase. To analyze the dynamical quantum transitions for the quenched and pulsed dynamics we combined the Weierstrass factorization technique for entire functions and the Lanczos exact diagonalization method. For a small system we obtained analytical results including the rate function of the Loschmidt echo. Exact numerical calculations for a system up to 40 spins confirm phase transition. Quench-induced dynamical transitions have been extensively studied recently. Here we show that related dynamical transitions can be achieved and controlled by appropriate electric field pulses.

  12. Nonelastic nuclear reactions induced by light ions with the BRIEFF code

    CERN Document Server

    Duarte, H

    2010-01-01

    The intranuclear cascade (INC) code BRIC has been extended to compute nonelastic reactions induced by light ions on target nuclei. In our approach the nucleons of the incident light ion move freely inside the mean potential of the ion in its center-of-mass frame while the center-of-mass of the ion obeys to equations of motion dependant on the mean nuclear+Coulomb potential of the target nucleus. After transformation of the positions and momenta of the nucleons of the ion into the target nucleus frame, the collision term between the nucleons of the target and of the ion is computed taking into account the partial or total breakup of the ion. For reactions induced by low binding energy systems like deuteron, the Coulomb breakup of the ion at the surface of the target nucleus is an important feature. Preliminary results of nucleon production in light ion induced reactions are presented and discussed.

  13. Neuropilin-1 promotes epithelial-to-mesenchymal transition by stimulating nuclear factor-kappa B and is associated with poor prognosis in human oral squamous cell carcinoma.

    Directory of Open Access Journals (Sweden)

    Weiming Chu

    Full Text Available The epithelial-to-mesenchymal transition (EMT is a key process in carcinogenesis, invasion, and metastasis of oral squamous cell carcinoma (OSCC. In our previous studies, we found that neuropilin-1 (NRP1 is overexpressed in tongue squamous cell carcinoma and that this overexpression is associated with cell migration and invasion. Nuclear factor-kappa B (NF-κB plays an essential role both in the induction and the maintenance of EMT and tumor metastasis. Therefore, we hypothesized that NRP1 induces EMT, and that NRP1-induced migration and invasion may be an important mechanism for promoting invasion and metastasis of OSCC through NF-κB activation.The variations in gene and protein expression and the changes in the biological behavior of OSCC cell lines transfected with a vector encoding NRP1, or the corresponding vector control, were evaluated. NRP1 overexpression promoted EMT and was associated with enhanced invasive and metastatic properties. Furthermore, the induction of EMT promoted the acquisition of some cancer stem cell (CSC-like characteristics in OSCC cells. We addressed whether selective inhibition of NF-κB suppresses the NRP1-mediated EMT by treating cells with pyrrolidinedithiocarbamate ammonium (PDTC, an inhibitor of NF-κB. Immunohistochemical analysis of NRP1 in OSCC tissue samples further supported a key mediator role for NRP1 in tumor progression, lymph node metastasis, and indicated that NRP1 is a predictor for poor prognosis in OSCC patients.Our results indicate that NRP1 may regulate the EMT process in OSCC cell lines through NF-κB activation, and that higher NRP1 expression levels are associated with lymph node metastasis and poor prognosis in OSCC patients. Further investigation of the role of NRP1 in tumorigenesis may help identify novel targets for the prevention and therapy of oral cancers.

  14. Origin of nonlinear transport across the magnetically induced superconductor-metal-insulator transition in two dimensions.

    Science.gov (United States)

    Seo, Y; Qin, Y; Vicente, C L; Choi, K S; Yoon, Jongsoo

    2006-08-04

    We have studied the effect of perpendicular magnetic fields and temperatures on nonlinear electronic transport in amorphous Ta superconducting thin films. The films exhibit a magnetic field-induced metallic behavior intervening the superconductor-insulator transition in the zero temperature limit. We show that the phase-identifying nonlinear transport in the superconducting and metallic phases arises from an intrinsic origin, not from an electron heating effect. The nonlinear transport is found to accompany an extraordinarily long voltage response time.

  15. Inducing the Internationalisation of Family Manufacturing Firms from a Transition Context

    DEFF Research Database (Denmark)

    Marinova, Svetla Trifonova; Marinov, Marin Alexandrov

    2017-01-01

    into the start of internationalisation via exporting and its initiating features. Design/methodology/approach – The study employs a qualitative research approach. Data were collected through semi-structured interviews from informants with conclusive decision-making power and subsequently analysed using...... to early export inducement despite the fusion of ownership and control, and regardless of transition context volatility and inefficiency. Research limitations/implications - The limitations include the sample size and its industry embeddedness confining generalisability. The key implications...

  16. Asbestos-Induced Mesothelial to Fibroblastic Transition Is Modulated by the Inflammasome.

    Science.gov (United States)

    Thompson, Joyce K; MacPherson, Maximilian B; Beuschel, Stacie L; Shukla, Arti

    2017-03-01

    Despite the causal relationship established between malignant mesothelioma (MM) and asbestos exposure, the exact mechanism by which asbestos induces this neoplasm and other asbestos-related diseases is still not well understood. MM is characterized by chronic inflammation, which is believed to play an intrinsic role in the origin of this disease. We recently found that asbestos activates the nod-like receptor family member containing a pyrin domain 3 (NLRP3) inflammasome in a protracted manner, leading to an up-regulation of IL-1β and IL-18 production in human mesothelial cells. Combined with biopersistence of asbestos fibers, we hypothesize that this creates an environment of chronic IL-1β signaling in human mesothelial cells, which may promote mesothelial to fibroblastic transition (MFT) in an NLRP3-dependent manner. Using a series of experiments, we found that asbestos induces a fibroblastic transition of mesothelial cells with a gain of mesenchymal markers (vimentin and N-cadherin), whereas epithelial markers, such as E-cadherin, are down-regulated. Use of siRNA against NLRP3, recombinant IL-1β, and IL-1 receptor antagonist confirmed the role of NLRP3 inflammasome-dependent IL-1β in the process. In vivo studies using wild-type and various inflammasome component knockout mice also revealed the process of asbestos-induced mesothelial to fibroblastic transition and its amelioration in caspase-1 knockout mice. Taken together, our data are the first to suggest that asbestos induces mesothelial to fibroblastic transition in an inflammasome-dependent manner. Copyright © 2017 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

  17. Doxorubicin-induced thiol-dependent alteration of cardiac mitochondrial permeability transition and respiration

    OpenAIRE

    P. De Oliveira; Santos,M.; Wallace, K

    2006-01-01

    Abstract Doxorubicin (DOX) is a highly effective treatment for several forms of cancer. However, clinical experience shows that DOX induces a cumulative and dose-dependent cardiomyopathy that has been ascribed to redox-cycling of the drug on the mitochondrial respiratory chain generating free radicals and oxidative stress in the process. Mitochondrial dysfunction including induction of the mitochondrial permeability transition (MPT) and inhibition of mitochondrial respiration have been impli...

  18. The ectopic expression of Snail in MDBK cells does not induce epithelial-mesenchymal transition

    OpenAIRE

    IZAWA, GENYA; Kobayashi, Wakako; Haraguchi, Misako; Sudo, Akiharu; Ozawa, Masayuki

    2015-01-01

    Epithelial-mesenchymal transition (EMT), a key process in the tumor metastatic cascade, is characterized by the loss of cell-cell junctions and cell polarity, as well as by the acquisition of migratory and invasive properties. However, the precise molecular events that initiate this complex EMT process are poorly understood. Snail expression induces EMT in Madin-Darby canine kidney (MDCK) cells and the human epidermoid carcinoma cell line, A431. Snail is a zinc finger transcription factor and...

  19. A quantum-mechanical study of rotational transitions in H2 induced by H

    CERN Document Server

    Wrathmall, S A

    2006-01-01

    Cross sections have been computed for rotational transitions of H2, induced by collisions with H atoms, using a recent H - H2 potential calculated by Mielke et al. [1]. These results are compared with those obtained with earlier potentials. Significant discrepancies are found with results deriving from the potential of Boothroyd et al. [3] in the low collision energy regime. We compare also cross sections derived using different levels of approximation to the vibrational motion.

  20. Pressure-induced Phase Transition in Oleic Acid Studied by Raman Spectroscopy

    Institute of Scientific and Technical Information of China (English)

    FAN Ya; ZHOU Jing; LI Shuang; GUAN Fu-Ying; XU Da-Peng

    2011-01-01

    High-pressure Raman studies up to 0.84 GPa are performed on oleic acid.Spectral analysis indicates that oleic acid undergoes a pressure-induced phase transition in the 0.29-0.36 GPa range.Only one high-pressure phase below 0.84 GPa is present,in which the polymethylene chains take the ordered all-trans conformation,with the methyl end of the chains exhibiting the ordered tt chain-end conformation and the olefin group taking the skewcis-skew' conformation.The conformational characters of the oleic acid molecule show that the high-pressure phase is the same as the low-temperature crystalline γ phase.The pressure-induced phase transition is typical of first-order transitions and the transition path during compression is different from that during cooling.Oleic acid (C1sH34O2) is one of the unsaturated fatty acids that appear naturally in a liquid state.It is one of the most common components of human diets,preventing coronary disease and breast cancer and benefiting people with diabetes.[1] A molecule of oleic acid possesses a carbon double bond,C =C,which leads to the occurrence of a phase transition when pressure is applied.[2] Therefore,the significance of high-pressure processing has recently increased as an alternative method of food preservation.So far some physical properties of oleic acid under pressures below 1 GPa have been investigated using a piston-cylinder device as a high-pressure apparatus.[2-10] However,no high-pressure Raman or any other in-situ experimental research on pressure-induced phase transition in oleic acid has been reported.In addition,the freezing point of oleic acid is 13.3℃,below which oleic acid crystallizes in three forms,namely,α,β and γ[11-17]%High-pressure Raman studies up to 0.84 Gpa are performed on oleic acid. Spectral analysis indicates that oleic acid undergoes a pressure-induced phase transition in the 0.29-0.36 Gpa range. Only one high-pressure phase below 0.84 Gpa is present, in which the polymethylene chains take the

  1. Nuclear dynamics of radiation-induced foci in euchromatin and heterochromatin

    Energy Technology Data Exchange (ETDEWEB)

    Chiolo, Irene; Tang, Jonathan; Georgescu, Walter; Costes, Sylvain V.

    2013-10-01

    Repair of double strand breaks (DSBs) is essential for cell survival and genome integrity. While much is known about the molecular mechanisms involved in DSB repair and checkpoint activation, the roles of nuclear dynamics of radiation-induced foci (RIF) in DNA repair are just beginning to emerge. Here, we summarize results from recent studies that point to distinct features of these dynamics in two different chromatin environments: heterochromatin and euchromatin. We also discuss how nuclear architecture and chromatin components might control these dynamics, and the need of novel quantification methods for a better description and interpretation of these phenomena. These studies are expected to provide new biomarkers for radiation risk and new strategies for cancer detection and treatment.

  2. Helicobacter pylori infection induces genetic instability of nuclear and mitochondrial DNA in gastric cells

    DEFF Research Database (Denmark)

    Machado, Ana Manuel Dantas; Figueiredo, Ceu; Touati, Eliette

    2009-01-01

    of genetic instabilities in the nuclear and mitochondrial DNA (mtDNA) were examined. EXPERIMENTAL DESIGN: We observed the effects of H. pylori infection on a gastric cell line (AGS), on C57BL/6 mice, and on individuals with chronic gastritis. In AGS cells, the effect of H. pylori infection on base excision...... cells and chronic gastritis tissue were determined by PCR, single-stranded conformation polymorphism, and sequencing. H. pylori vacA and cagA genotyping was determined by multiplex PCR and reverse hybridization. RESULTS: Following H. pylori infection, the activity and expression of base excision repair...... and MMR are down-regulated both in vitro and in vivo. Moreover, H. pylori induces genomic instability in nuclear CA repeats in mice and in mtDNA of AGS cells and chronic gastritis tissue, and this effect in mtDNA is associated with bacterial virulence. CONCLUSIONS: Our results suggest that H. pylori...

  3. Nuclear dynamics of radiation-induced foci in euchromatin and heterochromatin

    Energy Technology Data Exchange (ETDEWEB)

    Chiolo, Irene; Georgescu, Walter; Tang, Jonathan; Costes, Sylvain V.

    2013-09-03

    Repair of double strand breaks (DSBs) is essential for cell survival and genome integrity. While much is known about the molecular mechanisms involved in DSB repair and checkpoint activation, the roles of nuclear dynamics of radiation-induced foci (RIF) in DNA repair are just beginning to emerge. Here, we summarize results from recent studies that point to distinct features of these dynamics in two different chromatin environments: heterochromatin and euchromatin. We also discuss how nuclear architecture and chromatin components might control these dynamics, and the need of novel quantification methods for a better description and interpretation of these phenomena. These studies are expected to provide new biomarkers for radiation risk and new strategies for cancer detection and treatment.

  4. Relativistic effects in the intermolecular interaction-induced nuclear magnetic resonance parameters of xenon dimer

    DEFF Research Database (Denmark)

    Hanni, Matti; Lantto, Perttu; Ilias, Miroslav

    2007-01-01

    Relativistic effects on the 129Xe nuclear magnetic resonance shielding and 131Xe nuclear quadrupole coupling (NQC) tensors are examined in the weakly bound Xe2 system at different levels of theory including the relativistic four-component Dirac-Hartree-Fock (DHF) method. The intermolecular...... interaction-induced binary chemical shift d, the anisotropy of the shielding tensor ?s, and the NQC constant along the internuclear axis ?ll are calculated as a function of the internuclear distance. DHF shielding calculations are carried out using gauge-including atomic orbitals. For comparison, the full...... leading-order one-electron Breit-Pauli perturbation theory (BPPT) is applied using a common gauge origin. Electron correlation effects are studied at the nonrelativistic (NR) coupled-cluster singles and doubles with perturbational triples [CCSD(T)] level of theory. The fully relativistic second...

  5. Influence of irradiation-induced disorder on the Peierls transition in TTF-TCNQ microdomains

    Science.gov (United States)

    Solovyeva, Vita; Cmyrev, Anastasia; Sachser, Roland; Reith, Heiko; Huth, Michael

    2011-09-01

    The combined influence of electron irradiation-induced defects, substrate-induced strain and finite size effects on the electronic transport properties of individual micron-sized thin film growth domains of the organic charge transfer compound tetrathiafulvalene- tetracyanoquinodimethane (TTF-TCNQ) have been studied. The TTF-TCNQ domains have been isolated and electrically contacted by focused ion beam etching and focused ion and electron-beam-induced deposition, respectively. This allowed us to measure the temperature-dependent resistivity and the current-voltage characteristics of individual domains. The dependence of the resistivity on temperature follows a variable-range hopping behaviour which shows a crossover of the exponents as the Peierls transition is approached. The low temperature behaviour is analysed within the segmented rod model of Fogler, Teber and Shklovskii which was developed for charge-ordered quasi one-dimensional electron crystals (Fogler et al 2004 Phys. Rev. B 69 035413). The effect of substrate-induced biaxial strain on the Peierls transition temperature is discussed with regard to its interplay with the defect-induced changes.

  6. Influence of irradiation-induced disorder on the Peierls transition in TTF-TCNQ microdomains

    Energy Technology Data Exchange (ETDEWEB)

    Solovyeva, Vita; Cmyrev, Anastasia; Sachser, Roland; Huth, Michael [Physikalisches Institut, Goethe Universitaet, Max-von-Laue-Str. 1, 60438 Frankfurt am Main (Germany); Reith, Heiko, E-mail: levitan@physik.uni-frankfurt.de [Institute for Microtechnologies (IMtech) RheinMain University of Applied Sciences, Am Brueckweg 26, 65428 Ruesselsheim (Germany)

    2011-09-28

    The combined influence of electron irradiation-induced defects, substrate-induced strain and finite size effects on the electronic transport properties of individual micron-sized thin film growth domains of the organic charge transfer compound tetrathiafulvalene- tetracyanoquinodimethane (TTF-TCNQ) have been studied. The TTF-TCNQ domains have been isolated and electrically contacted by focused ion beam etching and focused ion and electron-beam-induced deposition, respectively. This allowed us to measure the temperature-dependent resistivity and the current-voltage characteristics of individual domains. The dependence of the resistivity on temperature follows a variable-range hopping behaviour which shows a crossover of the exponents as the Peierls transition is approached. The low temperature behaviour is analysed within the segmented rod model of Fogler, Teber and Shklovskii which was developed for charge-ordered quasi one-dimensional electron crystals (Fogler et al 2004 Phys. Rev. B 69 035413). The effect of substrate-induced biaxial strain on the Peierls transition temperature is discussed with regard to its interplay with the defect-induced changes.

  7. Strain induced magnetic transitions and spin reorientations in quantum paraelectric EuTiO3 material

    Science.gov (United States)

    Li, Chengdi; Zhao, Jinglong; Dong, Zhengchao; Zhong, Chonggui; Huang, Yanyan; Min, Yi; Wang, Meng; Zhou, Pengxia

    2015-05-01

    Strain induced magnetic transitions and spin reorientations in quantum paraelectric EuTiO3 material have been investigated using the first-principles calculations based on density functional theory. Four kinds of magnetic configurations and three possible directions of magnetic moments in every configuration are taken into consideration, respectively, in paraelectric and ferroelectric phases induced by the biaxial compressive and tensile strains. The calculated results indicate that the strain, regardless of the compressive or tensile strain, can induce not only the magnetic transitions from G-type antiferromagnetic to ferromagnetic phase, but also the reorientation of spin polarization in EuTiO3. The compressive strain can induce a ferromagnetic phase with spin polarization along a axis while the tensile one make magnetic moments along c axis. The further analysis for the electronic density of states (DOS) discover that the magnetic moment direction of EuTiO3 have intrinsic correlation with these orbitals, where the density of states are the most localized. In addition, Anderson super-exchange model is proposed to explain the changes of exchange coupling properties induced by the biaxial strains.

  8. Fluid shear stress induces epithelial-mesenchymal transition (EMT) in Hep-2 cells

    Science.gov (United States)

    Shen, Yang; Zhang, Yingying; Yin, Hongmei; Zeng, Ye; Liu, Jingxia; Yan, Zhiping; Liu, Xiaoheng

    2016-01-01

    Laryngeal squamous cell carcinoma (LSCC) is one of the most commonly diagnosed malignancies with high occurrence of tumor metastasis, which usually exposes to fluid shear stress (FSS) in lymphatic channel and blood vessel. Epithelial-mesenchymal transition (EMT) is an important mechanism that induces metastasis and invasion of tumors. We hypothesized that FSS induced a progression of EMT in laryngeal squamous carcinoma. Accordingly, the Hep-2 cells were exposed to 1.4 dyn/cm2 FSS for different durations. Our results showed that most of cells changed their morphology from polygon to elongated spindle with well-organized F-actin and abundant lamellipodia/filopodia in protrusions. After removing the FSS, cells gradually recovered their flat polygon morphology. FSS induced Hep-2 cells to enhance their migration capacity in a time-dependent manner. In addition, FSS down-regulated E-cadherin, and simultaneously up-regulated N-cadherin, translocated β-catenin into the nucleus. These results confirmed that FSS induced the EMT in Hep-2 cells, and revealed a reversible mesenchymal-epithelial transition (MET) process when FSS was removed. We further examined the time-expressions of signaling cascades, and demonstrated that FSS induces the EMT and enhances cell migration depending on integrin-ILK/PI3K-AKT-Snail signaling events. The current study suggests that FSS, an important biophysical factor in tumor microenvironment, is a potential determinant of cell behavior and function regulation. PMID:27096955

  9. Distinct cytoplasmic and nuclear functions of the stress induced protein DDIT3/CHOP/GADD153.

    Directory of Open Access Journals (Sweden)

    Alexandra Jauhiainen

    Full Text Available DDIT3, also known as GADD153 or CHOP, encodes a basic leucine zipper transcription factor of the dimer forming C/EBP family. DDIT3 is known as a key regulator of cellular stress response, but its target genes and functions are not well characterized. Here, we applied a genome wide microarray based expression analysis to identify DDIT3 target genes and functions. By analyzing cells carrying tamoxifen inducible DDIT3 expression constructs we show distinct gene expression profiles for cells with cytoplasmic and nuclear localized DDIT3. Of 175 target genes identified only 3 were regulated by DDIT3 in both cellular localizations. More than two thirds of the genes were downregulated, supporting a role for DDIT3 as a dominant negative factor that could act by either cytoplasmic or nuclear sequestration of dimer forming transcription factor partners. Functional annotation of target genes showed cell migration, proliferation and apoptosis/survival as the most affected categories. Cytoplasmic DDIT3 affected more migration associated genes, while nuclear DDIT3 regulated more cell cycle controlling genes. Cell culture experiments confirmed that cytoplasmic DDIT3 inhibited migration, while nuclear DDIT3 caused a G1 cell cycle arrest. Promoters of target genes showed no common sequence motifs, reflecting that DDIT3 forms heterodimers with several alternative transcription factors that bind to different motifs. We conclude that expression of cytoplasmic DDIT3 regulated 94 genes. Nuclear translocation of DDIT3 regulated 81 additional genes linked to functions already affected by cytoplasmic DDIT3. Characterization of DDIT3 regulated functions helps understanding its role in stress response and involvement in cancer and degenerative disorders.

  10. Catalytic Efficiency Is a Function of How Rhodium(I) (5 + 2) Catalysts Accommodate a Conserved Substrate Transition State Geometry: Induced Fit Model for Explaining Transition Metal Catalysis.

    Science.gov (United States)

    Mustard, Thomas J L; Wender, Paul A; Cheong, Paul Ha-Yeon

    2015-03-06

    The origins of differential catalytic reactivities of four Rh(I) catalysts and their derivatives in the (5 + 2) cycloaddition reaction were elucidated using density functional theory. Computed free energy spans are in excellent agreement with known experimental rates. For every catalyst, the substrate geometries in the transition state remained constant (Catalytic efficiency is shown to be a function of how well the catalyst accommodates the substrate transition state geometry and electronics. This shows that the induced fit model for explaining biological catalysis may be relevant to transition metal catalysis. This could serve as a general model for understanding the origins of efficiencies of catalytic reactions.

  11. Three-Dimensional Reconstruction of Nuclear Envelope Architecture Using Dual-Color Metal-Induced Energy Transfer Imaging.

    Science.gov (United States)

    Chizhik, Anna M; Ruhlandt, Daja; Pfaff, Janine; Karedla, Narain; Chizhik, Alexey I; Gregor, Ingo; Kehlenbach, Ralph H; Enderlein, Jörg

    2017-09-20

    The nuclear envelope, comprising the inner and the outer nuclear membrane, separates the nucleus from the cytoplasm and plays a key role in cellular functions. Nuclear pore complexes (NPCs), which are embedded in the nuclear envelope, control transport of macromolecules between the two compartments. Here, using dual-color metal-induced energy transfer (MIET), we determine the axial distance between Lap2β and Nup358 as markers for the inner nuclear membrane and the cytoplasmic side of the NPC, respectively. Using MIET imaging, we reconstruct the 3D profile of the nuclear envelope over the whole basal area, with an axial resolution of a few nanometers. This result demonstrates that optical microscopy can achieve nanometer axial resolution in biological samples and without recourse to complex interferometric approaches.

  12. β-Amyloid induces nuclear protease-mediated lamin fragmentation independent of caspase activation.

    Science.gov (United States)

    Ramasamy, Vijay Sankar; Islam, Md Imamul; Haque, Md Aminul; Shin, Song Yub; Park, Il-Seon

    2016-06-01

    β-Amyloid (Aβ), a hallmark peptide of Alzheimer's disease, induces both caspase-dependent apoptosis and non-apoptotic cell death. In this study, we examined caspase-independent non-apoptotic cell death preceding caspase activation in Aβ42-treated cells. We first determined the optimal treatment conditions for inducing cell death without caspase activation and selected a double-treatment method involving the incubation of cells with Aβ42 for 4 and 6 h (4+6 h sample). We observed that levels of lamin A (LA) and lamin B (LB) were reduced in the 4+6 h samples. This reduction was decreased by treatment with suc-AAPF-CMK, an inhibitor of nuclear scaffold (NS) protease, but not by treatment with z-VAD-FMK, a pan-caspase inhibitor. In addition, suc-AAPF-CMK decreased the changes in nuclear morphology observed in cells in the 4+6 h samples, which were different from nuclear fragmentation observed in STS-treated cells. Furthermore, suc-AAPF-CMK inhibited cell death in the 4+6 h samples. LA and LB fragmentation occurred in the isolated nuclei and was also inhibited by suc-AAPF-CMK. Together, these data indicated that the fragmentation of LA and LB in the Aβ42-treated cells was induced by an NS protease, whose identity is not clearly determined yet. A correlation between Aβ42 toxicity and the lamin fragmentation by NS protease suggests that inhibition of the protease could be an effective method for controlling the pathological process of AD.

  13. Neutron induced fission cross section measurements aimed at nuclear technology development

    CERN Document Server

    Belloni, Francesca; Rui, R

    2010-01-01

    Neutron induced fission cross sections of 233U, 238U, 241Am, 243Am and 245Cm in the energy range between 500 keV and 20 MeV obtained at the n_TOF Neutron Time of Flight facility at CERN (Genève) are presented. Fission fragments had been detected by a gas counter with good discrimination between nuclear fission products and background events. A comparison between the extracted cross sections, previous experimental results and evaluated libraries is reported.

  14. Stimulus-induced transition of clustering firings in neuronal networks with information transmission delay

    Science.gov (United States)

    Wang, Qingyun; Zhang, Honghui; Chen, Guanrong

    2013-07-01

    We study the evolution of spatiotemporal dynamics and transition of clustering firing synchronization on spiking Hodgkin-Huxley neuronal networks as information transmission delay and the periodic stimulus are varied. In particular, it is shown that the tuned information transmission delay can induce a clustering anti-phase synchronization transition with the pacemaker, where two equal clusters can alternatively synchronize in anti-phase firing. More interestingly, we show that the periodic stimulus can drive the delay-induced clustering anti-phase firing synchronization bifurcate to the collective perfect synchronization, which is routed by the complex process including collective chaotic firings and clustering out-of-phase synchronization of the neuronal networks. In addition, the periodic stimulus induced clustering firings of the spiking neuronal networks are robust to the connectivity probability of small world networks. Furthermore, the different stimulus frequency induced complexity is also investigated. We hope that the results of this paper can provide insights that could facilitate the understanding of the joint impact of information transmission delays and periodic stimulus on controlling dynamical behaviors of realistic neuronal networks.

  15. Bleomycin induced epithelial–mesenchymal transition (EMT) in pleural mesothelial cells

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Li-Jun [Department of Respiratory and Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei (China); Ye, Hong [Department of Pathophysiology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei (China); Key Laboratory of Pulmonary Diseases, Ministry of Health of China, Wuhan, Hubei (China); Zhang, Qian; Li, Feng-Zhi; Song, Lin-Jie; Yang, Jie; Mu, Qing [Department of Respiratory and Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei (China); Rao, Shan-Shan [Department of Pathophysiology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei (China); Cai, Peng-Cheng [Department of Clinical Laboratory, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei (China); Xiang, Fei; Zhang, Jian-Chu [Department of Respiratory and Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei (China); Key Laboratory of Pulmonary Diseases, Ministry of Health of China, Wuhan, Hubei (China); Su, Yunchao [Department of Pharmacology and Toxicology, Medical College of Georgia, Georgia Regents University, Augusta, GA (United States); Xin, Jian-Bao, E-mail: 814643835@qq.com [Department of Respiratory and Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei (China); Key Laboratory of Pulmonary Diseases, Ministry of Health of China, Wuhan, Hubei (China); Ma, Wan-Li, E-mail: whmawl@aliyun.com [Department of Respiratory and Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei (China); Key Laboratory of Pulmonary Diseases, Ministry of Health of China, Wuhan, Hubei (China)

    2015-03-01

    Idiopathic pulmonary fibrosis (IPF) is a chronic progressive lung disease characterized by the development of subpleural foci of myofibroblasts that contribute to the exuberant fibrosis. Recent studies revealed that pleural mesothelial cells (PMCs) undergo epithelial–mesenchymal transition (EMT) and play a pivotal role in IPF. In animal model, bleomycin induces pulmonary fibrosis exhibiting subpleural fibrosis similar to what is seen in human IPF. It is not known yet whether bleomycin induces EMT in PMCs. In the present study, PMCs were cultured and treated with bleomycin. The protein levels of collagen-I, mesenchymal phenotypic markers (vimentin and α-smooth muscle actin), and epithelial phenotypic markers (cytokeratin-8 and E-cadherin) were measured by Western blot. PMC migration was evaluated using wound-healing assay of culture PMCs in vitro, and in vivo by monitoring the localization of PMC marker, calretinin, in the lung sections of bleomycin-induced lung fibrosis. The results showed that bleomycin induced increases in collagen-I synthesis in PMC. Bleomycin induced significant increases in mesenchymal phenotypic markers and decreases in epithelial phenotypic markers in PMC, and promoted PMC migration in vitro and in vivo. Moreover, TGF-β1-Smad2/3 signaling pathway involved in the EMT of PMC was demonstrated. Taken together, our results indicate that bleomycin induces characteristic changes of EMT in PMC and the latter contributes to subpleural fibrosis. - Highlights: • Bleomycin induces collagen-I synthesis in pleural mesothelial cells (PMCs). • Bleomycin induces increases in vimentin and α-SMA protein in PMCs. • Bleomycin induces decreases in cytokeratin-8 and E-cadherin protein in PMCs • TGF-β1-Smad2/3 signaling pathway is involved in the PMC EMT induced by bleomycin.

  16. Radiation induced dissolution of UO 2 based nuclear fuel - A critical review of predictive modelling approaches

    Science.gov (United States)

    Eriksen, Trygve E.; Shoesmith, David W.; Jonsson, Mats

    2012-01-01

    Radiation induced dissolution of uranium dioxide (UO 2) nuclear fuel and the consequent release of radionuclides to intruding groundwater are key-processes in the safety analysis of future deep geological repositories for spent nuclear fuel. For several decades, these processes have been studied experimentally using both spent fuel and various types of simulated spent fuels. The latter have been employed since it is difficult to draw mechanistic conclusions from real spent nuclear fuel experiments. Several predictive modelling approaches have been developed over the last two decades. These models are largely based on experimental observations. In this work we have performed a critical review of the modelling approaches developed based on the large body of chemical and electrochemical experimental data. The main conclusions are: (1) the use of measured interfacial rate constants give results in generally good agreement with experimental results compared to simulations where homogeneous rate constants are used; (2) the use of spatial dose rate distributions is particularly important when simulating the behaviour over short time periods; and (3) the steady-state approach (the rate of oxidant consumption is equal to the rate of oxidant production) provides a simple but fairly accurate alternative, but errors in the reaction mechanism and in the kinetic parameters used may not be revealed by simple benchmarking. It is essential to use experimentally determined rate constants and verified reaction mechanisms, irrespective of whether the approach is chemical or electrochemical.

  17. Pressure controlled transition into a self-induced topological superconducting surface state

    KAUST Repository

    Zhu, Zhiyong

    2014-02-07

    Ab-initio calculations show a pressure induced trivial-nontrivial-trivial topological phase transition in the normal state of 1T-TiSe2. The pressure range in which the nontrivial phase emerges overlaps with that of the superconducting ground state. Thus, topological superconductivity can be induced in protected surface states by the proximity effect of superconducting bulk states. This kind of self-induced topological surface superconductivity is promising for a realization of Majorana fermions due to the absence of lattice and chemical potential mismatches. For appropriate electron doping, the formation of the topological superconducting surface state in 1T-TiSe 2 becomes accessible to experiments as it can be controlled by pressure.

  18. Time-resolved lattice measurements of shock-induced phase transitions in polycrystalline materials

    Science.gov (United States)

    Milathianaki, Despina

    The response of materials under extreme temperature and pressure conditions is a topic of great significance because of its relevance in astrophysics, geophysics, and inertial confinement fusion. In recent years, environments exceeding several hundred gigapascals in pressure have been produced in the laboratory via laser-based dynamic loading techniques. Shock-loading is of particular interest as the shock provides a fiducial for measuring time-dependent processes in the lattice such as phase transitions. Time-resolved x-ray diffraction is the only technique that offers an insight into these shock-induced processes at the relevant spatial (atomic) and temporal scales. In this study, nanosecond resolution x-ray diffraction techniques were developed and implemented towards the study of shock-induced phase transitions in polycrystalline materials. More specifically, the capability of a focusing x-ray diffraction geometry in high-resolution in situ lattice measurements was demonstrated by probing shock-compressed Cu and amorphous metallic glass samples. In addition, simultaneous lattice and free surface velocity measurements of shock-compressed Mg in the ambient hexagonal close packed (hcp) and shock-induced body centered cubic (bcc) phases between 12 and 45 GPa were performed. These measurements revealed x-ray diffraction signals consistent with a compressed bcc lattice above a shock pressure of 26.2+/-1.3 GPa, thus capturing for the first time direct lattice evidence of a shock-induced hcp to bcc phase transition in Mg. Our measurement of the hcp-bcc phase boundary in Mg was found to be consistent with the calculated boundary from generalized pseudopotential theory in the pressure and temperature region intersected by the principal shock Hugoniot. Furthermore, the subnanosecond timescale of the phase transition implied by the shock-loading conditions was in agreement with the kinetics of a martensitic transformation. In conclusion, we report on the progress and

  19. Catalytic effect of transition metals on microwave-induced degradation of atrazine in mineral micropores.

    Science.gov (United States)

    Hu, Erdan; Cheng, Hefa

    2014-06-15

    With their high catalytic activity for redox reactions, transition metal ions (Cu(2+) and Fe(3+)) were exchanged into the micropores of dealuminated Y zeolites to prepare effective microporous mineral sorbents for sorption and microwave-induced degradation of atrazine. Due to its ability to complex with atrazine, loading of copper greatly increased the sorption of atrazine. Atrazine sorption on iron-exchanged zeolites was also significantly enhanced, which was attributed to the hydrolysis of Fe(3+) polycations in mineral micropores and electrostatic interactions of protonated atrazine molecules with the negatively charged pore wall surface. Copper and iron species in the micropores also significantly accelerated degradation of the sorbed atrazine (and its degradation intermediates) under microwave irradiation. The catalytic effect was attributed to the easy reducibility and high oxidation activity of Cu(2+) and Fe(3+) species stabilized in the micropores of the zeolites. It was postulated that the surface species of transition metals (monomeric Cu(2+), Cu(2+)-O-Cu(2+) complexes, FeO(+), and dinuclear Fe-O-Fe-like species) in the mineral micropores were thermally activated under microwave irradiation, and subsequently formed highly reactive sites catalyzing oxidative degradation of atrazine. The transition metal-exchanged zeolites, particularly the iron-exchanged ones, were relatively stable when leached under acidic conditions, which suggests that they are reusable in sorption and microwave-induced degradation. These findings offer valuable insights on designing of effective mineral sorbents that can selectively uptake atrazine from aqueous solutions and catalyze its degradation under microwave irradiation.

  20. Superconductivity in HfTe5 across weak to strong topological insulator transition induced via pressures.

    Science.gov (United States)

    Liu, Y; Long, Y J; Zhao, L X; Nie, S M; Zhang, S J; Weng, Y X; Jin, M L; Li, W M; Liu, Q Q; Long, Y W; Yu, R C; Gu, C Z; Sun, F; Yang, W G; Mao, H K; Feng, X L; Li, Q; Zheng, W T; Weng, H M; Dai, X; Fang, Z; Chen, G F; Jin, C Q

    2017-03-16

    Recently, theoretical studies show that layered HfTe5 is at the boundary of weak &strong topological insulator (TI) and might crossover to a Dirac semimetal state by changing lattice parameters. The topological properties of 3D stacked HfTe5 are expected hence to be sensitive to pressures tuning. Here, we report pressure induced phase evolution in both electronic &crystal structures for HfTe5 with a culmination of pressure induced superconductivity. Our experiments indicated that the temperature for anomaly resistance peak (Tp) due to Lifshitz transition decreases first before climbs up to a maximum with pressure while the Tp minimum corresponds to the transition from a weak TI to strong TI. The HfTe5 crystal becomes superconductive above ~5.5 GPa where the Tp reaches maximum. The highest superconducting transition temperature (Tc) around 5 K was achieved at 20 GPa. Crystal structure studies indicate that HfTe5 transforms from a Cmcm phase across a monoclinic C2/m phase then to a P-1 phase with increasing pressure. Based on transport, structure studies a comprehensive phase diagram of HfTe5 is constructed as function of pressure. The work provides valuable experimental insights into the evolution on how to proceed from a weak TI precursor across a strong TI to superconductors.

  1. Large reversible magnetocaloric effect induced by metamagnetic transition in antiferromagnetic HoNiGa compound

    Science.gov (United States)

    Wang, Yi-Xu; Zhang, Hu; Wu, Mei-Ling; Tao, Kun; Li, Ya-Wei; Yan, Tim; Long, Ke-Wen; Long, Teng; Pang, Zheng; Long, Yi

    2016-12-01

    The magnetic properties and magnetocaloric effects (MCE) of HoNiGa compound are investigated systematically. The HoNiGa exhibits a weak antiferromagnetic (AFM) ground state below the Ńeel temperature TN of 10 K, and the AFM ordering could be converted into ferromagnetic (FM) ordering by external magnetic field. Moreover, the field-induced FM phase exhibits a high saturation magnetic moment and a large change of magnetization around the transition temperature, which then result in a large MCE. A large -ΔSM of 22.0 J/kg K and a high RC value of 279 J/kg without magnetic hysteresis are obtained for a magnetic field change of 5 T, which are comparable to or even larger than those of some other magnetic refrigerant materials in the same temperature range. Besides, the μ0H2/3 dependence of well follows the linear fitting according to the mean-field approximation, suggesting the nature of second-order FM-PM magnetic transition under high magnetic fields. The large reversible MCE induced by metamagnetic transition suggests that HoNiGa compound could be a promising material for magnetic refrigeration in low temperature range. Project supported by the National Natural Science Foundation of China (Grant Nos. 51671022 and 51427806), the Beijing Natural Science Foundation, China (Grant No. 2162022), and the Fundamental Research Funds for the Central Universities, China (Grant No. FRF-TP-15-002A3).

  2. Temperature induced structural transitions from native to unfolded aggregated states of tobacco etch virus protease

    Science.gov (United States)

    Zhu, Guo-Fei; Ren, Si-Yan; Xi, Lei; Du, Lin-Fang; Zhu, Xiao-Feng

    2015-02-01

    Tobacco etch virus protease (TEVp) is widely used to remove fusion tags from recombinant proteins because of its high and unique specificity. This work describes the conformational and the thermodynamic properties in the unfolding/refolding process of TEVp3M (three-point mutant: L56V/S135G/S219V) induced by temperature. With temperature increasing from 20 to 100 °C, the CD spectra showed a transition trend from α-helix to β-sheet, and the fluorescence emission, synchronous fluorescence, ANS and RLS spectroscopy consistently revealed that the temperature-induced unfolding process behaved in a three-state manner, for there was a relatively stable intermediate state observed around 50 °C. The reversibility of thermal unfolding of TEVp3M further showed that the transition from the native to the intermediate state was reversible (below 50 °C), however the transition from the intermediate to the unfolded state was irreversible (above 60 °C). Moreover, aggregates were observed above 60 °C as revealed by SDS-PAGE, Thioflavin-T fluorescence and Congo red absorbance.

  3. Discontinuous bundling transition in semiflexible polymer networks induced by Casimir interactions

    Science.gov (United States)

    Kachan, Devin; Müller, Kei W.; Wall, Wolfgang A.; Levine, Alex J.

    2016-09-01

    Fluctuation-induced interactions are an important organizing principle in a variety of soft matter systems. We investigate the role of fluctuation-based or thermal Casimir interactions between cross linkers in a semiflexible network. One finds that, by integrating out the polymer degrees of freedom, there is an attractive logarithmic potential between nearest-neighbor cross linkers in a bundle, with a significantly weaker next-nearest-neighbor interaction. Here we show that a one-dimensional gas of these strongly interacting linkers in equilibrium with a source of unbound ones admits a discontinuous phase transition between a sparsely and a densely bound bundle. This discontinuous transition induced by the long-ranged nature of the Casimir interaction allows for a similarly abrupt structural transition in semiflexible filament networks between a low cross linker density isotropic phase and a higher cross link density bundle network. We support these calculations with the results of finite element Brownian dynamics simulations of semiflexible filaments and transient cross linkers.

  4. Chirality-sensitive nuclear magnetic resonance effects induced by indirect spin-spin coupling

    Science.gov (United States)

    Garbacz, P.; Buckingham, A. D.

    2016-11-01

    It is predicted that, for two spin-1/2 nuclei coupled by indirect spin-spin coupling in a chiral molecule, chirality-sensitive induced electric polarization can be observed at the frequencies equal to the sum and difference between the spin resonance frequencies. Also, an electric field oscillating at the difference frequency can induce spin coherences which allow the direct discrimination between enantiomers by nuclear magnetic resonance. The dominant contribution to the magnitude of these expected chiral effects is proportional to the permanent electric dipole moment and to the antisymmetric part of the indirect spin-spin coupling tensor of the chiral molecule. Promising compounds for experimental tests of the predictions are derivatives of 1,3-difluorocyclopropene.

  5. Determination of energetic neutron spatial distribution using neutron induced nuclear recoil events

    CERN Document Server

    Hashemi-Nezhad, S R; Brandt, R; Westmeier, W; Odoj, R; Krivopustov, M I; Kulakov, B A; Sosnin, A N

    2002-01-01

    Neutron induced nuclear recoils were used to determine the spatial distribution of the weakly moderated spallation neutrons produced in the interaction of 1 GeV protons with lead and uranium-lead targets. CR39 plastic track detectors were used to record neutron-induced recoil tracks. The track density measurements were carried out using a fully automated optical microscope. The experimental results were compared with Monte Carlo simulations using MCNPX-2.1.5 code and an extension code that was written for this purpose. A good agreement was found between the experiment and calculations for normalised results. Applicability of the MCNPX-2.1.5 code for absolute recoil track density determination is discussed.

  6. Dependence of ion-induced Pd-silicide formation on nuclear energy deposition density

    Energy Technology Data Exchange (ETDEWEB)

    Horino, Yuji; Matsunami, Noriaki; Itoh, Noriaki

    1986-05-01

    Pd/sub 2/Si formation at the Pd-Si interface induced by irradiation with ions having a wide range of nuclear energy of deposition density has been investigated. It is found that the thickness of the silicide layer formed by irradiation is proportional to the ion fluence for irradiation with ions having low energy-deposition densities, while it is proportional to the square root of the fluence for irradiation with ions having energy-deposition densities. The results indicate that Pd/sub 2/Si formation is reaction limited when the energy-deposition density at the interface is low and is diffusion limited when it is high. The results are compared with the phenomenological theory developed by Horino et al. and it is shown that such a dependence of the limiting processes on the energy depositon density is induced when the diffusion is thermally activated while the reaction at the interface is radiation-enhanced.

  7. Magnetic-field-induced valence transition in rare-earth systems

    Indian Academy of Sciences (India)

    G Gangadhar Reddy; A Ramakanth; S K Ghatak

    2002-05-01

    The magnetic-field-induced valence transition in rare-earth systems has been investigated using the periodic Anderson model supplemented by the Falicov–Kimball term. This model has been solved by first decoupling the Falicov–Kimball term as proposed by Khomskii and Koharjan and then taking the limit of infinite intra-site Coulomb repulsion. The valence transition both in the absence and in the presence of magnetic field as a function of temperature is studied. It has been found that the system makes transition from non-magnetic to magnetic state when the magnetic field increases beyond a critical value c. The phase boundary defined in terms of reduced field c()/c(0) and reduced temperature /v (v being the valence transition temperature in the absence of field) is almost independent of the position of the localized level. The results are in qualitative agreement with experimental observations in Yb- and Eu-compounds.

  8. Substitution- and strain-induced magnetic phase transition in iron carbide

    Science.gov (United States)

    Odkhuu, Dorj; Tsogbadrakh, N.; Dulmaa, A.; Otgonzul, N.; Naranchimeg, D.

    2016-10-01

    Cementite-type carbides are of interest for magnetocaloric applications owing to their temperature- or pressure-induced magnetic phase transition. Here, using first-principles calculations, we investigate the magnetism and the magnetic phase transition in iron carbide (Fe3C) with the substitution of Cr atoms at Fe sites with the strain effect. The presence of Cr atoms is found to give rise to a second-order magnetic phase transition from a ferromagnetic phase for Fe3C to a nonmagnetic phase in chromium carbide (Cr3C).While the ternary Fe2CrC and Cr2FeC compounds prefer the ferrimagnetic ground state, the magnitudes of both the Fe and Cr spin moments, which are antiparallel in orientation, decrease as x increases in Fe3-xCrxC ( x = 0, 1, 2, and 3). Furthermore, the fixed spin-moment calculations indicate that the magnetization of Fe3-xCrxC compounds can be delicately altered via the strain effect and that the magnetic-nonmagnetic phase transition occurs at an early stage of Cr substitution, x = 2.

  9. A time-dependent Ginzburg-Landau phase field formalism for shock-induced phase transitions

    Science.gov (United States)

    Haxhimali, Tomorr; Belof, Jonathan L.; Benedict, Lorin X.

    2017-01-01

    Phase-field models have become popular in the last two decades to describe a host of free-boundary problems. The strength of the method relies on implicitly describing the dynamics of surfaces and interfaces by a continuous scalar field that enters the global grand free energy functional of the system. Here we explore the potential utility of this method in order to describe shock-induced phase transitions. To this end we make use of the Multiphase Field Theory (MFT) to account for the existence of multiple phases during the transition, and we couple MFT to a hydrodynamic model in the context of a new LLNL code for phase transitions, SAMSA. As a demonstration of this approach, we apply our code to the α - ɛ-Fe phase transition under shock wave loading conditions and compare our results with experiments of Jensen et. al. [J. Appl. Phys., 105:103502 (2009)] and Barker and Hollenbach [J. Appl. Phys., 45:4872 (1974)].

  10. Phase transitions in ensembles of solitons induced by an optical pumping or a strong electric field

    Science.gov (United States)

    Karpov, P.; Brazovskii, S.

    2016-09-01

    The latest trend in studies of modern electronically and/or optically active materials is to provoke phase transformations induced by high electric fields or by short (femtosecond) powerful optical pulses. The systems of choice are cooperative electronic states whose broken symmetries give rise to topological defects. For typical quasi-one-dimensional architectures, those are the microscopic solitons taking from electrons the major roles as carriers of charge or spin. Because of the long-range ordering, the solitons experience unusual super-long-range forces leading to a sequence of phase transitions in their ensembles: the higher-temperature transition of the confinement and the lower one of aggregation into macroscopic walls. Here we present results of an extensive numerical modeling for ensembles of both neutral and charged solitons in both two- and three-dimensional systems. We suggest a specific Monte Carlo algorithm preserving the number of solitons, which substantially facilitates the calculations, allows to extend them to the three-dimensional case and to include the important long-range Coulomb interactions. The results confirm the first confinement transition, except for a very strong Coulomb repulsion, and demonstrate a pattern formation at the second transition of aggregation.

  11. An Investigation of Magnetically Induced Structural Phase Transitions Near a Magnetic Phase Boundary

    Science.gov (United States)

    Brown, D. E.; Hoffmann, C. A.; Hua, J.; Totapally, S.; Mais, J.; Chmaissem, O.; Dabrowski, B.; Ren, Yang

    2004-03-01

    The structural properties of the perovskite La_1-xSr_xMnO_3, x = 0.55, have been studied using synchrotron powder x-ray diffraction under high magnetic fields (up to 6 Tesla) for zero field cooled and field cooled conditions. This compound has an interesting phase transition point where both structural and magnetic properties change. As temperature decreases, it undergoes a tetragonal (I4/mcm) to orthorhombic (Fmmm) first-order structural phase transition while simultaneously undergoing a ferromagnetic to an A-type antiferromagnetic magnetic phase transition. Under the application of a strong magnetic field, the structure can be forced from the ferromagnetic tetragonal structure to the antiferromagnetic orthorhombic structure, which is nearly a reversible process. Thus the strong competition between the magnetic phases can be significantly affected by applying an external magnetic field. The magnetic perovskites, such as the colossal magnetoresistive materials, appear to be susceptible to such large and surprising magnetically induced phase transitions. Work at NIU is supported by the State of Illinois under HECA. Work at APS/ANL is supported by the US DOE-BES No. W-31-109-ENG-38.

  12. SOX4 Mediates TGF-beta-Induced Expression of Mesenchymal Markers during Mammary Cell Epithelial to Mesenchymal Transition

    NARCIS (Netherlands)

    Vervoort, Stephin J.; Lourenco, Ana Rita; van Boxtel, Ruben; Coffer, Paul J.

    2013-01-01

    The epithelial to mensenchymal transition program regulates various aspects of embryonic development and tissue homeostasis, but aberrant activation of this pathway in cancer contributes to tumor progression and metastasis. TGF-beta potently induces an epithelial to mensenchymal transition in cancer

  13. Role of nuclear factor-kappaB in interleukin-1-induced collagen degradation by corneal fibroblasts.

    Science.gov (United States)

    Lu, Ying; Fukuda, Ken; Li, Qin; Kumagai, Naoki; Nishida, Teruo

    2006-09-01

    The proinflammatory cytokine interleukin (IL)-1 is implicated in corneal ulceration. The role of nuclear factor (NF)-kappaB in the IL-1-induced degradation of collagen by corneal fibroblasts that underlies corneal ulceration was investigated. Rabbit corneal fibroblasts were cultured in three-dimensional gels of type I collagen with or without IL-1 and sulfasalazine, an inhibitor of NF-kappaB activation. Collagen degradation was assessed from the amount of hydroxyproline generated by acid-heat hydrolysis of culture supernatants. The release of matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) into culture supernatants was examined by immunoblot analysis and gelatin zymography, and the cellular abundance of MMP and TIMP mRNAs was determined by reverse transcription and real-time polymerase chain reaction analysis. The phosphorylation and degradation of the NF-kappaB-inhibitory protein IkappaB-alpha were examined by immunoblot analysis. The subcellular localization and DNA binding activity of the p65 subunit of NF-kappaB were evaluated by immunofluorescence analysis and with a colorimetric assay, respectively. The transactivation activity of NF-kappaB was assessed with a reporter gene assay. Sulfasalazine inhibited IL-1-induced collagen degradation by corneal fibroblasts in a concentration-dependent manner. It also inhibited the stimulatory effects of IL-1 on the synthesis or activation of various MMPs in a concentration-dependent manner. IL-1 induced the phosphorylation and degradation of IkappaB-alpha, the nuclear translocation and up-regulation of the DNA binding activity of the p65 subunit of NF-kappaB, and the activation of NF-kappaB in a manner sensitive to sulfasalazine. These results suggest that NF-kappaB contributes to the IL-1-induced degradation of collagen by corneal fibroblasts and is therefore a potential therapeutic target for treatment of corneal ulcers.

  14. Nuclear 111Cd probes detect a hidden symmetry change at the γ → α transition in cerium considered isostructural for 60 years

    Science.gov (United States)

    Tsvyashchenko, A. V.; Nikolaev, A. V.; Velichkov, A. I.; Salamatin, A. V.; Fomicheva, L. N.; Ryasny, G. K.; Sorokin, A. A.; Kochetov, O. I.; Budzynski, M.

    2010-10-01

    We use the time-differential perturbed angular correlation technique to study nuclear electric quadupole hyperfine interactions of probe 111Cd nuclei in cerium lattice sites at room temperature under pressures up to 8 GPa. We have found that the well known γ → α phase transition in cerium is not isostructural. In α-Ce, the probe 111Cd nuclei reveal a quadrupole electron charge density component that is absent in γ-Ce. The hidden spacial structure of electronic quadrupoles in α-Ce is triple-q antiferroquadrupolar, as was suggested in [14]. We relate our findings to the current understanding of the γ → α phase transition and also report on nuclear quadrupole interactions in other high-pressure phases of cerium: α″ ( C2/ m space symmetry) and α' (α-U structure).

  15. Pressure-induced structural, magnetic and transport transitions in Sr2FeO3 from first-principles

    Directory of Open Access Journals (Sweden)

    Ting Jia

    2017-05-01

    Full Text Available The serial system Srn+1FenO2n+1(n=1,2,3… with the FeO4 square planar motif exhibits abundant phase transitions under pressure. In this work, we investigate the pressure-induced structural, magnetic and transport transitions in Sr2FeO3 from first-principles. Our results show that the system undergoes a structural transition from Immm to Ammm when the volume decreases by 30%, together with a spin-state transition (SST from high-spin (S = 2 to intermediate-spin (S = 1, an antiferromagnetic-to-ferromagnetic transition and an insulator-to-metal transition (IMT. Besides, the IMT here is a bandwidth controlled transition, but little influenced by the SST.

  16. Propofol and magnesium attenuate isoflurane-induced caspase-3 activation via inhibiting mitochondrial permeability transition pore

    Directory of Open Access Journals (Sweden)

    Zhang Yiying

    2012-08-01

    Full Text Available Abstract Background The inhalation anesthetic isoflurane has been shown to open the mitochondrial permeability transition pore (mPTP and induce caspase activation and apoptosis, which may lead to learning and memory impairment. Cyclosporine A, a blocker of mPTP opening might attenuate the isoflurane-induced mPTP opening, lessening its ripple effects. Magnesium and anesthetic propofol are also mPTP blockers. We therefore set out to determine whether propofol and magnesium can attenuate the isoflurane-induced caspase activation and mPTP opening. Methods We investigated the effects of magnesium sulfate (Mg2+, propofol, and isoflurane on the opening of mPTP and caspase activation in H4 human neuroglioma cells stably transfected to express full-length human amyloid precursor protein (APP (H4 APP cells and in six day-old wild-type mice, employing Western blot analysis and flowcytometry. Results Here we show that Mg2+ and propofol attenuated the isoflurane-induced caspase-3 activation in H4-APP cells and mouse brain tissue. Moreover, Mg2+ and propofol, the blockers of mPTP opening, mitigated the isoflurane-induced mPTP opening in the H4-APP cells. Conclusion These data illustrate that Mg2+ and propofol may ameliorate the isoflurane-induced neurotoxicity by inhibiting its mitochondrial dysfunction. Pending further studies, these findings may suggest the use of Mg2+ and propofol in preventing and treating anesthesia neurotoxicity.

  17. ATM induces MacroD2 nuclear export upon DNA damage

    Science.gov (United States)

    Golia, Barbara; Moeller, Giuliana Katharina; Jankevicius, Gytis; Schmidt, Andreas; Hegele, Anna; Preißer, Julia; Tran, Mai Ly; Imhof, Axel; Timinszky, Gyula

    2017-01-01

    ADP-ribosylation is a dynamic post-translation modification that regulates the early phase of various DNA repair pathways by recruiting repair factors to chromatin. ADP-ribosylation levels are defined by the activities of specific transferases and hydrolases. However, except for the transferase PARP1/ARDT1 little is known about regulation of these enzymes. We found that MacroD2, a mono-ADP-ribosylhydrolase, is exported from the nucleus upon DNA damage, and that this nuclear export is induced by ATM activity. We show that the export is dependent on the phosphorylation of two SQ/TQ motifs, suggesting a novel direct interaction between ATM and ADP-ribosylation. Lastly, we show that MacroD2 nuclear export temporally restricts its recruitment to DNA lesions, which may decrease the net ADP-ribosylhydrolase activity at the site of DNA damage. Together, our results identify a novel feedback regulation between two crucial DNA damage-induced signaling pathways: ADP-ribosylation and ATM activation. PMID:28069995

  18. H 2 inhibition of radiation induced dissolution of spent nuclear fuel

    Science.gov (United States)

    Trummer, Martin; Roth, Olivia; Jonsson, Mats

    2009-01-01

    In order to elucidate the effect of noble metal clusters in spent nuclear fuel on the kinetics of radiation induced spent fuel dissolution we have used Pd particle doped UO 2 pellets. The catalytic effect of Pd particles on the kinetics of radiation induced dissolution of UO 2 during γ-irradiation in HCO3- containing solutions purged with N 2 and H 2 was studied in this work. Four pellets with Pd concentrations of 0%, 0.1%, 1% and 3% were produced to mimic spent nuclear fuel. The pellets were placed in 10 mM HCO3- aqueous solutions and γ-irradiated, and the dissolution of UO22+ was measured spectrophotometrically as a function of time. Under N 2 atmosphere, 3% Pd prevent the dissolution of uranium by reduction with the radiolytically produced H 2, while the other pellets show a rate of dissolution of around 1.6 × 10 -9 mol m -2 s -1. Under H 2 atmosphere already 0.1% Pd effectively prevents the dissolution of uranium, while the rate of dissolution for the pellet without Pd is 1.4 × 10 -9 mol m -2 s -1. It is also shown in experiments without radiation in aqueous solutions containing H 2O 2 and O 2 that ɛ-particles catalyze the oxidation of the UO 2 matrix by these molecular oxidants, and that the kinetics of the catalyzed reactions is close to diffusion controlled.

  19. Oxidative stress induces persistent telomeric DNA damage responsible for nuclear morphology change in mammalian cells.

    Directory of Open Access Journals (Sweden)

    Elisa Coluzzi

    Full Text Available One main function of telomeres is to maintain chromosome and genome stability. The rate of telomere shortening can be accelerated significantly by chemical and physical environmental agents. Reactive oxygen species are a source of oxidative stress and can produce modified bases (mainly 8-oxoG and single strand breaks anywhere in the genome. The high incidence of guanine residues in telomeric DNA sequences makes the telomere a preferred target for oxidative damage. Our aim in this work is to evaluate whether chromosome instability induced by oxidative stress is related specifically to telomeric damage. We treated human primary fibroblasts (MRC-5 in vitro with hydrogen peroxide (100 and 200 µM for 1 hr and collected data at several time points. To evaluate the persistence of oxidative stress-induced DNA damage up to 24 hrs after treatment, we analysed telomeric and genomic oxidative damage by qPCR and a modified comet assay, respectively. The results demonstrate that the genomic damage is completely repaired, while the telomeric oxidative damage persists. The analysis of telomere length reveals a significant telomere shortening 48 hrs after treatment, leading us to hypothesise that residual telomere damage could be responsible for the telomere shortening observed. Considering the influence of telomere length modulation on genomic stability, we quantified abnormal nuclear morphologies (Nucleoplasmic Bridges, Nuclear Buds and Micronuclei and observed an increase of chromosome instability in the same time frame as telomere shortening. At subsequent times (72 and 96 hrs, we observed a restoration of telomere length and a reduction of chromosome instability, leaving us to conjecture a correlation between telomere shortening/dysfunction and chromosome instability. We can conclude that oxidative base damage leads to abnormal nuclear morphologies and that telomere dysfunction is an important contributor to this effect.

  20. Nonequilibrium transition induced by mass media in a model for social influence.

    Science.gov (United States)

    González-Avella, J C; Cosenza, M G; Tucci, K

    2005-12-01

    We study the effect of mass media, modeled as an applied external field, on a social system based on Axelrod's model for the dissemination of culture. The numerical simulations show that the system undergoes a nonequilibrium phase transition between an ordered phase (homogeneous culture) specified by the mass media and a disordered (culturally fragmented) one. The critical boundary separating these phases is calculated on the parameter space of the system, given by the intensity of the mass media influence and the number of options per cultural attribute. Counterintuitively, mass media can induce cultural diversity when its intensity is above some threshold value. The nature of the phase transition changes from continuous to discontinuous at some critical value of the number of options.

  1. Field induced magnetic phase transition as a magnon Bose Einstein condensation

    Directory of Open Access Journals (Sweden)

    Teodora Radu et al

    2007-01-01

    Full Text Available We report specific heat, magnetocaloric effect and magnetization measurements on single crystals of the frustrated quasi-2D spin -½ antiferromagnet Cs2CuCl4 in the external magnetic field 0≤B≤12 T along a-axis and in the temperature range 0.03 K≤T≤6 K. Decreasing the applied magnetic field B from high fields leads to the closure of the field induced gap in the magnon spectrum at a critical field Bcsimeq8.44 T and a long-range incommensurate state below Bc. In the vicinity of Bc, the phase transition boundary is well described by the power law TN~(Bc-B1/phi with the measured critical exponent phisimeq1.5. These findings provide experimental evidence that the scaling law of the transition temperature TN can be described by the universality class of 3D Bose–Einstein condensation (BEC of magnons.

  2. Pressure-induced structure phase transition on Y sub 2 O sub 3

    CERN Document Server

    Ma Yan Ming; Ma Hong An; Pan Yue Wu; Cui Qi Liang; Liu Bing Bing; Cui Tian; Zou Guang Tian; LiuJing

    2002-01-01

    Diamond anvil cell (DAC) is adopted to carry out in situ high pressure measurements for Y sub 2 O sub 3 powder sample in the range from ambient to 23 GPa, by using synchrotron X-ray diffraction method. Two structural phase transitions were observed in the pressure range. At P = 12.8 GPa, Y sub 2 O sub 3 transforms from cubic to monoclinic structure. At P = 21.8 GPa, Y sub 2 O sub 3 transforms from monoclinic to another new phase. However, the crystal structure of the new phase cannot be determined, because the diffraction pattern of the sample disappears. The decompressed sample is monoclinic structure, indicating that the first pressure-induced phase transition is irreversible

  3. Inducing the Internationalisation of Family Manufacturing Firms from a Transition Context

    DEFF Research Database (Denmark)

    Marinova, Svetla Trifonova; Marinov, Marin Alexandrov

    2017-01-01

    a combination of inductive and deductive coding. Findings – The findings show that the sample firms internationalised early exhibiting mostly proactive behaviour in finding international clients. Owners-managers’ international orientation and commitment combined with contacts in their social spaces lead...... to early export inducement despite the fusion of ownership and control, and regardless of transition context volatility and inefficiency. Research limitations/implications - The limitations include the sample size and its industry embeddedness confining generalisability. The key implications...... with the straight forward decision-making process that is safeguarded by the full family ownership can abate the dissuading role of the perceived lack of institutional support for SME internationalisation in the studied transition context....

  4. Phase transition of a symmetric diblock copolymer induced by nanorods with different surface chemistry

    Science.gov (United States)

    Guo, Yu-qi; Pan, Jun-xing; Sun, Min-na; Zhang, Jin-jun

    2017-01-01

    We investigate the phase transition of a symmetric diblock copolymer induced by nanorods with different surface chemistry. The results demonstrate that the system occurs the phase transition from a disordered structure to ordered parallel lamellae and then to the tilted layered structure as the number of rods increases. The dynamic evolution of the domain size and the order parameter of the microstructure are also examined. Furthermore, the influence of rod property, rod-phase interaction, rod-rod interaction, rod length, and polymerization degree on the behavior of the polymer system is also investigated systematically. Moreover, longer amphiphilic nanorods tend to make the polymer system form the hexagonal structure. It transforms into a perpendicular lamellar structure as the polymerization degree increases. Our simulations provide an efficient method for determining how to obtain the ordered structure on the nanometer scales and design the functional materials with optical, electronic, and magnetic properties.

  5. Traffic states and jamming transitions induced by a bus in two-lane traffic flow

    Science.gov (United States)

    Nagai, Ryoichi; Nagatani, Takashi; Taniguchi, Naoki

    2005-05-01

    We study the traffic states and jamming transitions induced by a bus (slow car) in a two-lane traffic of cars. We use the dynamic model which is an extended one of the optimal velocity model to take into account the lane changing. The fundamental (flow-density) diagram is presented. The fundamental diagram changes highly by introducing a bus on a two-lane roadway. It is found that there are the six distinct states for the two-lane traffic flow including a bus. The spatio-temporal patterns are presented for the distinct traffic states. The dynamical state of traffic changes with density of cars. It is shown that the dynamical transitions among the distinct traffic states occur at some values of density. The phase diagram (region map) is shown for the two-lane traffic flow including a bus.

  6. Epithelial-mesenchymal transition: molecular pathways of hepatitis viruses-induced hepatocellular carcinoma progression.

    Science.gov (United States)

    Panebianco, Concetta; Saracino, Chiara; Pazienza, Valerio

    2014-08-01

    Hepatocellular carcinoma is the fifth most common tumor and the third cause of death for cancer in the world. Among the main causative agents of this tumor is the chronic infection by hepatitis viruses B and C, which establish a context of chronic inflammation degenerating in fibrosis, cirrhosis, and, finally, cancer. Recent findings, however, indicate that hepatitis viruses are not only responsible for cancer onset but also for its progression towards metastasis. Indeed, they are able to promote epithelial-mesenchymal transition, a process of cellular reprogramming underlying tumor spread. In this manuscript, we review the currently known molecular mechanisms by which hepatitis viruses induce epithelial-mesenchymal transition and, thus, hepatocellular carcinoma progression.

  7. Threshold for plasma phase transition of aluminum single crystal induced by hypervelocity impact

    Energy Technology Data Exchange (ETDEWEB)

    Ju, Yuanyuan; Zhang, Qingming, E-mail: qmzhang@bit.edu.cn [State Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology, Beijing 100081 (China)

    2015-12-15

    Molecular dynamics method is used to study the threshold for plasma phase transition of aluminum single crystal induced by hypervelocity impact. Two effective simulation methods, piston-driven method and multi-scale shock technique, are used to simulate the shock wave. The simulation results from the two methods agree well with the experimental data, indicating that the shock wave velocity is linearly dependent on the particle velocity. The atom is considered to be ionized if the increase of its internal energy is larger than the first ionization energy. The critical impact velocity for plasma phase transition is about 13.0 km/s, corresponding to the threshold of pressure and temperature which is about 220 GPa and 11.0 × 10{sup 3 }K on the shock Hugoniot, respectively.

  8. Flagella-induced transitions in the collective behavior of confined microswimmers

    CERN Document Server

    Tsang, Alan Cheng Hou

    2014-01-01

    Bacteria exist in a free-swimming state or in a sessile biofilm state. The transition from free-swimming to sessile mode is characterized by changes in gene expression which alter, among others,the mechanics of flagellar motility. In this paper, we propose an idealized physical model to investigate the effects of flagellar activity on the hydrodynamic interactions among a population of microswimmers. We show that decreasing flagellar activity induces a hydrodynamically-triggered transition in confined microswimmers from turbulent-like swimming to aggregation and clustering. These results suggest that the interplay between flagellar activity and hydrodynamic interactions provides a physical mechanism for coordinating collective behaviors in confined bacteria, with potentially profound implications on biofilm initiation.

  9. Noise-induced dynamical phase transitions in long-range systems.

    Science.gov (United States)

    Chavanis, Pierre-Henri; Baldovin, Fulvio; Orlandini, Enzo

    2011-04-01

    In the thermodynamic limit, the time evolution of isolated long-range interacting systems is properly described by the Vlasov equation. This equation admits nonequilibrium dynamically stable stationary solutions characterized by a zero order parameter. We show that the presence of external noise sources, such as a heat bath, can reduce their lifetime and induce at a specific time a dynamical phase transition marked by a nonzero order parameter. This transition may be used as a distinctive experimental signature of the temporary existence of nonequilibrium Vlasov-stable states. In particular, we present evidence of a regime characterized by an order parameter pulse. Our analytical results are corroborated by numerical simulations of a paradigmatic long-range model.

  10. The influence of the level of lamina propria invasion and the prevalence of p53 nuclear accumulation on survival in stage T1 transitional cell bladder cancer

    DEFF Research Database (Denmark)

    Hermann, G G; Horn, T; Steven, K

    1998-01-01

    related to age, level of lamina propria invasion and presence of p53 nuclear accumulation. For this subpopulation overall survival was 67%, and 79% for stage T1a, 70% for stage T1b and 57% for stage T1c (p positive (61......PURPOSE: We assessed the influence of the level of lamina propria invasion and the prevalence of p53 nuclear immunoreactivity on the survival of patients with stage T1 transitional cell bladder cancer. MATERIALS AND METHODS: All patients presenting with stage T1 bladder cancer were prospectively...... and routinely grouped according to the level of lamina propria invasion. Invasion of the tumor stalk was defined as stage T1a, invasion of the lamina propria proper superficial to the level of muscularis mucosa as stage T1b and into or deeper than the muscularis mucosa as stage T1c. The p53 nuclear...

  11. Relative efficacy of some prokinetic drugs in morphine-induced gastrointestinal transit delay in mice

    Institute of Scientific and Technical Information of China (English)

    AD Suchitra; SA Dkhar; DG Shewade; CH Shashindran

    2003-01-01

    AIM: To study the relative efficacy of cisapride,metoclopramide, domperidone, erythromycin and mosapride on gastric emptying (GE) and small intestinal transit (SIT)in morphine treated mice.METHODS: Phenol red marker meal was employed to estimate GE and SIT in Swiss albino mice of either sex. The groups included were control, morphine 1 mg/kg (s.c. 15min before test meal) alone or with (45 min before test meal p.o.) cisapride 10 mg/kg, metoclopramide 20 mg/kg,domperidone 20 mg/kg, erythromycin 6 mg/kg and mosapride 20 mg/kg.RESULTS: Cisapride, metoclopramide and mosapride were effective in enhancing gastric emptying significantly (P<0.001)whereas other prokinetic agents failed to do so in normal mice. Metoclopramide completely reversed morphine induced delay in gastric emptying followed by mosapride.Metoclopramide alone was effective when given to normal mice in increasing the SIT. Cisapride, though it did not show any significant effect on SIT in normal mice, was able to reverse morphine induced delay in SIT significantly (P<0.001)followed by metoclopramide and mosapride.CONCLUSION: Metoclopramide and cisapride are most effective in reversing morphine-induced delay in gastric emptying and small intestinal transit in mice respectively.

  12. Isovalent Bi3+ substitution induced structural and magnetic transitions in LaMnO3

    Science.gov (United States)

    Joseph, D. Paul; Lin, J. W.; Kumar, N. Pavan; Chen, W. C.; Lin, J. G.

    2016-11-01

    Rare earth perovskite manganites have attracted renewed attention due to scientific aspect and prospective device applications. This work explores the structural and magnetic properties of La(1-x)BixMnO3 (x=0-0.5) with isovalent Bi3+ ions substituted at the La3+site synthesized through solid state reaction method. Doping of 'Bi3+' in LaMnO3 induces transition from orthorhombic to cubic phase for x≥ 0.3. Decrease in the magnetic transition temperature in ZFC-FC data is correlated to the distortion induced by 'Bi3+' doping. Spin glass like feature is witnessed in orthorhombic phase and it diminished appreciably for x≥0.3 in the cubic symmetry. At 10 K, coercivity decreases in orthorhombic phase, whereas it increases marginally in cubic phase. Thus, isovalent Bi3+ doping in LaMnO3 is found to induce structural change from orthorhombic to cubic which is also reflected in the magnetic properties as a change over from hard to soft magnetic phase. In addition, a phenomenological model is applied for fitting the field cooled magnetization data. The results of fitting and the related magneto-caloric effect are also discussed in this paper.

  13. MIR517C inhibits autophagy and the epithelial-to-mesenchymal (-like) transition phenotype in human glioblastoma through KPNA2-dependent disruption of TP53 nuclear translocation.

    Science.gov (United States)

    Lu, Yuntao; Xiao, Limin; Liu, Yawei; Wang, Hai; Li, Hong; Zhou, Qiang; Pan, Jun; Lei, Bingxi; Huang, Annie; Qi, Songtao

    2015-01-01

    The epithelial-to-mesenchymal (-like) transition (EMT), a crucial embryonic development program, has been linked to the regulation of glioblastoma (GBM) progression and invasion. Here, we investigated the role of MIR517C/miR-517c, which belongs to the C19MC microRNA cluster identified in our preliminary studies, in the pathogenesis of GBM. We found that MIR517C was associated with improved prognosis in patients with GBM. Furthermore, following treatment with the autophagy inducer temozolomide (TMZ) and low glucose (LG), MIR517C degraded KPNA2 (karyopherin alpha 2 [RAG cohort 1, importin alpha 1]) and subsequently disturbed the nuclear translocation of TP53 in the GBM cell line U87 in vitro. Interestingly, this microRNA could inhibit autophagy and reduce cell migration and infiltration in U87 cells harboring wild-type (WT) TP53, but not in U251 cells harboring mutant (MU) TP53. Moreover, the expression of epithelial markers (i.e., CDH13/T-cadherin and CLDN1 [claudin 1]) increased, while the expression of mesenchymal markers (i.e., CDH2/N-cadherin, SNAI1/Snail, and VIM [vimentin]) decreased, indicating that the EMT status was blocked by MIR517C in U87 cells. Compared with MIR517C overexpression, MIR517C knockdown promoted infiltration of U87 cells to the surrounding structures in nude mice in vivo. The above phenotypic changes were also observed in TP53(+/+) and TP53(-/-) HCT116 colon cancer cells. In summary, our study provided support for a link between autophagy and EMT status in WT TP53 GBM cells and provided evidence for the signaling pathway (MIR517C-KPNA2-cytoplasmic TP53) involved in attenuating autophagy and eliminating the increased migration and invasion during the EMT.

  14. Four-shell polyoxometalates featuring high-nuclearity Ln{sub 26} clusters. Structural transformations of nanoclusters into frameworks triggered by transition-metal ions

    Energy Technology Data Exchange (ETDEWEB)

    Li, Zhong; Li, Xin-Xiong; Yang, Tao; Cai, Zhen-Wen; Zheng, Shou-Tian [State Key Laboratory of Photocatalysis on Energy and Environment, College of Chemistry, Fuzhou University, Fujian (China)

    2017-03-01

    A series of polyoxometalates (POMs) that incorporate the highest-nuclearity Ln clusters that have been observed in such structures to date (Ln{sub 26}, Ln=La and Ce) are described, which exhibit giant multishell configurations (Ln is contained in W{sub 6} is contained in Ln{sub 26} is contained in W{sub 100}). Their structures are remarkably different from known giant POMs that feature multiple Ln ions. In particular, the incorporated Ln-O clusters with a nuclearity of 26 are significantly larger than known high-nuclearity (≤10) Ln-O clusters in POM chemistry. Furthermore, they also contain the largest number of La and Ce centers for any POM reported to date and represent a new kind of rare giant POMs with more than 100 W atoms. Interestingly, the La{sub 26}-containing POM can undergo a single-crystal to single-crystal structural transformation in the presence of various transition-metal ions, such as Cu{sup 2+}, Co{sup 2+}, and Ni{sup 2+}, from an inorganic molecular nanocluster into an inorganic-organic hybrid extended framework that is built from POM building blocks with even higher-nuclearity La{sub 28} clusters bridged by transition-metal complexes. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  15. Paeoniflorin prevents hypoxia-induced epithelial–mesenchymal transition in human breast cancer cells

    Directory of Open Access Journals (Sweden)

    Zhou Z

    2016-04-01

    Full Text Available Zhenyu Zhou,1,* Shunchang Wang,1,* Caijuan Song,2 Zhuang Hu11Department of Thyroid and Breast, Huaihe Hospital, Henan University, Kaifeng, 2Department of Immunization Program, Zhengzhou Center for Disease Control and Prevention, Zhengzhou, People’s Republic of China*These authors contributed equally to this workAbstract: Paeoniflorin (PF is a monoterpene glycoside extracted from the root of Paeonia lactiflora Pall. Previous studies have demonstrated that PF inhibits the growth, invasion, and metastasis of tumors in vivo and in vitro. However, the effect of PF on hypoxia-induced epithelial–mesenchymal transition (EMT in breast cancer cells remains unknown. Therefore, the objective of this study was to investigate the effect of PF on hypoxia-induced EMT in breast cancer cells, as well as characterize the underlying mechanism. The results presented in this study demonstrate that PF blocks the migration and invasion of breast cancer cells by repressing EMT under hypoxic conditions. PF also significantly attenuated the hypoxia-induced increase in HIF-1α level. Furthermore, PF prevented hypoxia-induced expression of phosphorylated PI3K and Akt in MDA-MB-231 cells. In conclusion, PF prevented hypoxia-induced EMT in breast cancer cells by inhibiting HIF-1α expression via modulation of PI3K/Akt signaling pathway. This finding provides evidence that PF can serve as a therapeutic agent for the treatment of breast cancer.Keywords: paeoniflorin, breast cancer, hypoxia, epithelial–mesenchymal transition, PI3K/Akt signaling pathway

  16. Statistical mechanics of random geometric graphs: Geometry-induced first-order phase transition.

    Science.gov (United States)

    Ostilli, Massimo; Bianconi, Ginestra

    2015-04-01

    Random geometric graphs (RGGs) can be formalized as hidden-variables models where the hidden variables are the coordinates of the nodes. Here we develop a general approach to extract the typical configurations of a generic hidden-variables model and apply the resulting equations to RGGs. For any RGG, defined through a rigid or a soft geometric rule, the method reduces to a nontrivial satisfaction problem: Given N nodes, a domain D, and a desired average connectivity 〈k〉, find, if any, the distribution of nodes having support in D and average connectivity 〈k〉. We find out that, in the thermodynamic limit, nodes are either uniformly distributed or highly condensed in a small region, the two regimes being separated by a first-order phase transition characterized by a O(N) jump of 〈k〉. Other intermediate values of 〈k〉 correspond to very rare graph realizations. The phase transition is observed as a function of a parameter a∈[0,1] that tunes the underlying geometry. In particular, a=1 indicates a rigid geometry where only close nodes are connected, while a=0 indicates a rigid antigeometry where only distant nodes are connected. Consistently, when a=1/2 there is no geometry and no phase transition. After discussing the numerical analysis, we provide a combinatorial argument to fully explain the mechanism inducing this phase transition and recognize it as an easy-hard-easy transition. Our result shows that, in general, ad hoc optimized networks can hardly be designed, unless to rely to specific heterogeneous constructions, not necessarily scale free.

  17. Silibinin induces apoptosis via calpain-dependent AIF nuclear translocation in U87MG human glioma cell death

    Directory of Open Access Journals (Sweden)

    Kim Yong K

    2011-04-01

    Full Text Available Abstract Background Silibinin, a natural polyphenolic flavonoid, has been reported to induce cell death in various cancer cell types. However, the molecular mechanism is not clearly defined. Our previous study showed that silibinin induces glioma cell death and its effect was effectively prevented by calpain inhibitor. The present study was therefore undertaken to examine the role of calpain in the silibinin-induced glioma cell death. Methods U87MG cells were grown on well tissue culture plates and cell viability was measured by MTT assay. ROS generation and △ψm were estimated using the fluorescence dyes. PKC activation and Bax expression were measured by Western blot analysis. AIF nuclear translocation was determined by Western blot and immunocytochemistry. Results Silibinin induced activation of calpain, which was blocked by EGTA and the calpain inhibitor Z-Leu-Leu-CHO. Silibinin caused ROS generation and its effect was inhibited by calpain inhibitor, the general PKC inhibitor GF 109203X, the specific PKCδ inhibitor rottlerin, and catalase. Silibinin-induce cell death was blocked by calpain inhibitor and PKC inhibitors. Silibinin-induced PKCδ activation and disruption of △ψm were prevented by the calpain inhibitor. Silibinin induced AIF nuclear translocation and its effect was prevented by calpain inhibitor. Transfection of vector expressing microRNA of AIF prevented the silibinin-induced cell death. Conclusions Silibinin induces apoptotic cell death through a calpain-dependent mechanism involving PKC, ROS, and AIF nuclear translocation in U87MG human glioma cells.

  18. Bimodality and others signatures of liquid-gas phase transition of nuclear matter; Bimodalite et autres signatures possibles de la transition de phase liquide-gaz de la matiere nucleaire

    Energy Technology Data Exchange (ETDEWEB)

    Pichon, M

    2004-10-01

    Nuclear matter must present a liquid-gas phase transition at intermediate energies. This thesis is a study of this transition with binary collisions of symmetrical systems Xe+Sn and Au+Au from 60 to 100 MeV/u, detected with INDRA multidetector. A possible signature of liquid-gas phase transition is the observation of a bimodal distribution for an order parameter. Bimodality is a robust signal and can differentiate two family of event: the liquid phase and the gas one. This study is made on the quasi-projectile source with an asymmetry variable between the two heaviest decay products. The sorting of the event is provided by the perpendicular energy of the light charged particles emitted on the quasi-target side. Delta-scaling and negative heat capacity are also interpreted as a possible signature of phase transition. For the first one, we observe scaling law of heaviest fragment distributions for each phase. For the second one, fluctuations of the sharing of the available energy in the system can lead to a negative branch of heat capacity which is a theoretical signature of the transition. Correlation between all this observables are clearly demonstrated. A possible contribution of dynamical effect is tested and quantified with the generator of event HIPSE. The conclusion reveals a definite coherence between all signals of a phase transition. (author)

  19. Comparison and characterization of α-amylase inducers in Aspergillus nidulans based on nuclear localization of AmyR

    OpenAIRE

    Murakoshi, Yuriko; Makita, Tomohiro; Kato, Masashi; Kobayashi, Tetsuo

    2012-01-01

    AmyR, a fungal transcriptional activator responsible for induction of amylolytic genes in Aspergillus nidulans, localizes to the nucleus in response to the physiological inducer isomaltose. Maltose, kojibiose, and d-glucose were also found to trigger the nuclear localization of GFP-AmyR. Isomaltose- and kojibiose-triggered nuclear localization was not inhibited by the glucosidase inhibitor, castanospermine, while maltose-triggered localization was inhibited. Thus, maltose itself does not appe...

  20. Cytokeratin 18 is necessary for initiation of TGF-β1-induced epithelial-mesenchymal transition in breast epithelial cells.

    Science.gov (United States)

    Jung, Hyejung; Kim, Bomin; Moon, Byung In; Oh, Eok-Soo

    2016-12-01

    During epithelial-mesenchymal transition (EMT), epithelial cells lose key phenotypic markers (e.g., E-cadherin and cytokeratin 18) and acquire mesenchymal markers (e.g., N-cadherin and vimentin). Although the loss of cytokeratin 18 is a hallmark of EMT, the regulatory role of cytokeratin 18 in EMT is not yet fully understood. Here, we report that cytokeratin 18 is involved in the regulation of transforming growth factor-beta1 (TGF-β1)-induced EMT in breast epithelial cells. When MCF10A cells were treated with TGF-β1 for 24 h, considerable morphological changes, indicative of the early stages of EMT (e.g., loss of cell-cell contact), were observed and cytokeratin 18 was downregulated. However, E-cadherin levels were not altered until a later time point. This suggests that cytokeratin 18 may play an active role during the earlier stages of EMT. Consistent with this notion, siRNA-mediated knockdown of cytokeratin 18 delayed TGF-β1-mediated EMT, and the associated downregulation of E-cadherin reduced the phosphorylation/nuclear localization of smad 2/3 and decreased the expression levels of snail and slug (which inhibit E-cadherin expression in epithelial cells as an early response to TGF-β1). Taken together, these results suggest that cytokeratin 18 critically contributes to initiating TGF-β1-induced EMT via the smad 2/3-mediated regulation of snail and slug expression in breast epithelial cells.

  1. Delay induced transitions in an asymmetry bistable system and stochastic resonance

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The delay Fokker-Planck equation is given for an asymmetry bistable system with correlated Gaussian white noises. The small delay approximation based on the probability density approach is used and the approximate stationary probability density function is obtained. The phenomenon of delay induced transitions is found. When a weak periodic signal is added, the phenomenon of stochastic resonance is investigated. Expression of the signal-to-noise ratio (SNR) is obtained by using the two-state theory. It is shown that the time delay can suppress or promote the stochastic resonance phenomenon.

  2. Laser-induced gratings in the gas phase excited via Raman-active transitions

    Energy Technology Data Exchange (ETDEWEB)

    Kozlov, D.N. [General Physics Inst., Russian Academy of Sciences, Moscow (Russian Federation); Bombach, R.; Hemmerling, B.; Hubschmid, W. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-06-01

    We report on a new time resolved coherent Raman technique that is based on the generation of thermal gratings following a population change among molecular levels induced by stimulated Raman pumping. This is achieved by spatially and temporally overlapping intensity interference patterns generated independently by two lasers. When this technique is used in carbon dioxide, employing transitions which belong to the Q-branches of the {nu}{sub 1}/2{nu}{sub 2} Fermi dyad, it is possible to investigate molecular energy transfer processes. (author) 2 figs., 10 refs.

  3. Quantum Oscillation Signatures of Pressure-induced Topological Phase Transition in BiTeI

    OpenAIRE

    Joonbum Park; Kyung-Hwan Jin; Jo, Y. J.; Choi, E. S.; Kang, W.; Kampert, E.; J.-S. Rhyee; Seung-Hoon Jhi; Jun Sung Kim

    2015-01-01

    We report the pressure-induced topological quantum phase transition of BiTeI single crystals using Shubnikov-de Haas oscillations of bulk Fermi surfaces. The sizes of the inner and the outer FSs of the Rashba-split bands exhibit opposite pressure dependence up to P = 3.35 GPa, indicating pressure-tunable Rashba effect. Above a critical pressure P ~ 2 GPa, the Shubnikov-de Haas frequency for the inner Fermi surface increases unusually with pressure, and the Shubnikov-de Haas oscillations for t...

  4. Multipartite non-locality and entanglement signatures of a field-induced quantum phase transition

    Science.gov (United States)

    Batle, Josep; Alkhambashi, Majid; Farouk, Ahmed; Naseri, Mosayeb; Ghoranneviss, Mahmood

    2017-02-01

    Quantum correlation measures are limited in practice to a few number of parties, since no general theory is still capable of reaching the thermodynamic limit. In the present work we study entanglement and non-locality for a cluster of spins belonging to a compound that displays a magnetocaloric effect. A quantum phase transition (QPT) is induced by an external magnetic field B, in such a way that the corresponding quantum fluctuations are reproduced at a much smaller scale than the experimental outcomes, and then described by means of the aforementioned quantum measures.

  5. Intrinsic Spin Hall Effect Induced by Quantum Phase Transition in HgCdTe Quantum Wells

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Wen; Chang, Kai; /Beijing, Inst. Semiconductors; Zhang, Shou-Cheng; /Stanford U., Phys. Dept.

    2010-03-19

    Spin Hall effect can be induced both by the extrinsic impurity scattering and by the intrinsic spin-orbit coupling in the electronic structure. The HgTe/CdTe quantum well has a quantum phase transition where the electronic structure changes from normal to inverted. We show that the intrinsic spin Hall effect of the conduction band vanishes on the normal side, while it is finite on the inverted side. This difference gives a direct mechanism to experimentally distinguish the intrinsic spin Hall effect from the extrinsic one.

  6. Geometry-induced phase transition from a bosonic superfluid to a Mott insulator

    Science.gov (United States)

    Barter, Thomas; Thomas, Claire; Leung, Tsz Him; Okano, Masayuki; Stamper-Kurn, Dan

    2016-05-01

    We describe a preliminary characterization of the superfluid and Mott insulating phases of ultracold Rb 87 bosonic atoms in a two-dimensional optical superlattice with tunable lattice geometry. By smoothly changing the lattice structure from the triangular to kagome geometries while maintaining near-constant tunneling and interaction energies, we observe a geometry-induced phase transition from the superfluid to the Mott-insulating state. We characterize the superfluid by measurements of the coherent population fraction in time of flight, and find that the superfluid is less robust in the kagome geometry than in the triangular lattice, owing to the lower its lower coordination number.

  7. Magnetization Studies of Field-Induced Transitions by Using a Single-Turn Coil Technique

    Science.gov (United States)

    Abe, N.; Matsuda, Y. H.; Takeyama, S.; Sato, K.; Kageyama, H.; Nishiwaki, Y.

    2013-03-01

    Some technical improvements for magnetization measurements using a vertical-type single-turn coil (V-STC) method have been attempted. We have chosen LaCoO3, RbCoBr3 and SrCu2(BO3)2 that show interesting field induced magnetic transitions, as test materials. Intriguing features were clearly observed in magnetic fields of up to 100 T. The quality of the data is of comparable to those obtained by a conventional non-destructive pulse magnet.

  8. Transitions in a Logistic Growth Model Induced by Noise Coupling and Noise Color

    Institute of Scientific and Technical Information of China (English)

    SHI Jin; ZHU Shi-Qun

    2006-01-01

    With unified colored noise approximation, the logistic growth model is used to analyze cancer cell population when colored noise is included. It is found that both the coupling between noise terms and the noise color can induce continuous first-order-like and re-entrance-like phase transitions in the system. The coupling and the noise color can also increase tumor cell growth for small number of cell mass and repress tumor cell growth for large number of cell mass. It is shown that the approximate analytic expressions are consistent with the numerical simulations.

  9. Itinerant type many-body theories for photo-induced structural phase transitions

    Science.gov (United States)

    Nasu, Keiichiro

    2004-09-01

    Itinerant type quantum many-body theories for photo-induced structural phase transitions (PSPTs) are reviewed in close connection with various recent experimental results related to this new optical phenomenon. There are two key concepts: the hidden multi-stability of the ground state, and the proliferations of optically excited states. Taking the ionic (I) rarr neutral (N) phase transition in the organic charge transfer (CT) crystal, TTF-CA, as a typical example for this type of transition, we, at first, theoretically show an adiabatic path which starts from CT excitons in the I-phase, but finally reaches an N-domain with a macroscopic size. In connection with this I-N transition, the concept of the initial condition sensitivity is also developed so as to clarify experimentally observed nonlinear characteristics of this material. In the next, using a more simplified model for the many-exciton system, we theoretically study the early time quantum dynamics of the exciton proliferation, which finally results in the formation of a domain with a large number of excitons. For this purpose, we derive a stepwise iterative equation to describe the exciton proliferation, and clarify the origin of the initial condition sensitivity. Possible differences between a photo-induced nonequilibrium phase and an equilibrium phase at high temperatures are also clarified from general and conceptional points of view, in connection with recent experiments on the photo-induced phase transition in an organo-metallic complex crystal. It will be shown that the photo-induced phase can make a new interaction appear as a broken symmetry only in this phase, even when this interaction is almost completely hidden in all the equilibrium phases, such as the ground state and other high-temperature phases. The relation between the photo-induced nonequilibrium phase and the hysteresis induced nonequilibrium one is also qualitatively discussed. We will be concerned with a macroscopic parity violation

  10. Itinerant type many-body theories for photo-induced structural phase transitions

    Energy Technology Data Exchange (ETDEWEB)

    Nasu, Keiichiro [Solid State Theory Division, Institute of Materials Structure Science, KEK, Graduate University for Advanced Study, 1-1, Oho, Tsukuba, Ibaraki, 305-0801 (Japan)

    2004-09-01

    Itinerant type quantum many-body theories for photo-induced structural phase transitions (PSPTs) are reviewed in close connection with various recent experimental results related to this new optical phenomenon. There are two key concepts: the hidden multi-stability of the ground state, and the proliferations of optically excited states. Taking the ionic (I) {yields} neutral (N) phase transition in the organic charge transfer (CT) crystal, TTF-CA, as a typical example for this type of transition, we, at first, theoretically show an adiabatic path which starts from CT excitons in the I-phase, but finally reaches an N-domain with a macroscopic size. In connection with this I-N transition, the concept of the initial condition sensitivity is also developed so as to clarify experimentally observed nonlinear characteristics of this material. In the next, using a more simplified model for the many-exciton system, we theoretically study the early time quantum dynamics of the exciton proliferation, which finally results in the formation of a domain with a large number of excitons. For this purpose, we derive a stepwise iterative equation to describe the exciton proliferation, and clarify the origin of the initial condition sensitivity. Possible differences between a photo-induced nonequilibrium phase and an equilibrium phase at high temperatures are also clarified from general and conceptional points of view, in connection with recent experiments on the photo-induced phase transition in an organo-metallic complex crystal. It will be shown that the photo-induced phase can make a new interaction appear as a broken symmetry only in this phase, even when this interaction is almost completely hidden in all the equilibrium phases, such as the ground state and other high-temperature phases. The relation between the photo-induced nonequilibrium phase and the hysteresis induced nonequilibrium one is also qualitatively discussed. We will be concerned with a macroscopic parity

  11. Lipopolysaccharide triggers nuclear import of Lpcat1 to regulate inducible gene expression in lung epithelia

    Institute of Scientific and Technical Information of China (English)

    Bryon; Ellis; Leah; Kaercher; Courtney; Snavely

    2012-01-01

    AIM:To report that Lpcat1 plays an important role in regulating lipopolysaccharide (LPS) inducible gene tran-scription. METHODS:Gene expression in Murine Lung Epithelial MLE-12 cells with LPS treatment or Haemophilus influenza and Escherichia coli infection was analyzed by employing quantitative Reverse Transcription Polymerase Chain Reaction techniques. Nucleofection was used to deliver Lenti-viral system to express or knock down Lpcat1 in MLE cells. Subcellular protein fractionation and Western blotting were utilized to study Lpcat1 nuclear relocation. RESULTS:Lpcat1 translocates into the nucleus from thecytoplasm in murine lung epithelia (MLE) after LPS treatment. Haemophilus influenza and Escherichia coli , two LPS-containing pathogens that cause pneumonia, triggered Lpcat1 nuclear translocation from the cytoplasm. The LPS inducible gene expression profile was determined by quantitative reverse transcription polymerase chain reaction after silencing Lpcat1 or overexpression of the enzyme in MLE cells. We detected that 17 out of a total 38 screened genes were upregulated, 14 genes were suppressed, and 7 genes remained unchanged in LPS treated cells in comparison to controls. Knockdown of Lpcat1 by shRNA dramatically changed the spectrum of the LPS inducible gene transcription, as 18 genes out of 38 genes were upregulated, of which 20 genes were suppressed or unchanged. Notably, in Lpcat1 overex-pressed cells, 25 genes out of 38 genes were reduced in the setting of LPS treatment.CONCLUSION:These observations suggest that Lpcat1 relocates into the nucleus in response to bacterial infection to differentially regulate gene transcriptional repression.

  12. TANGRA-Setup for the Investigation of Nuclear Fission induced by 14.1 MeV neutrons

    OpenAIRE

    RUSKOV I.; Kopatch, Y; BYSTRITSKY V.; Skoy, V.; SHVETSOV V.; Hambsch, Franz-Josef; Oberstedt, Stephan; CAPOTE NOY R.; Sedyshev, P.; GROZDANOV D.; IVANOV I. Zh.; ALEKSAKHIN V. Yu.; BOGOLUBOV E. P.; BARMAKOV Y.; Khabarov, S. V.

    2015-01-01

    The new experimental setup TANGRA (Tagged Neutrons & Gamma Rays), for the investigation of neutron induced nuclear reactions, e.g. (n,xn’), (n,xn’γ), (n,γ), (n,f), on a number of important isotopes for nuclear science and engineering (235,238U, 237Np, 239Pu, 244,245,248Cm) is under construction and being tested at the Frank Laboratory of Neutron Physics (FLNP) of the Joint Institute for Nuclear Research (JINR) in Dubna. The TANGRA setup consists of: a portable neutron generator ING-27, wit...

  13. An analytical study on excitation of nuclear-coupled thermal-hydraulic instability due to seismically induced resonance in BWR

    Energy Technology Data Exchange (ETDEWEB)

    Hirano, Masashi [Japan Atomic Energy Research Institute, Ibaraki-ken (Japan)

    1997-07-01

    This paper describes the results of a scoping study on seismically induced resonance of nuclear-coupled thermal-hydraulic instability in BWRs, which was conducted by using TRAC-BF1 within a framework of a point kinetics model. As a result of the analysis, it is shown that a reactivity insertion could occur accompanied by in-surge of coolant into the core resulted from the excitation of the nuclear-coupled instability by the external acceleration. In order to analyze this phenomenon more in detail, it is necessary to couple a thermal-hydraulic code with a three-dimensional nuclear kinetics code.

  14. Structural Insights into the Calcium-Mediated Allosteric Transition in the C-Terminal Domain of Calmodulin from Nuclear Magnetic Resonance Measurements.

    Science.gov (United States)

    Kukic, Predrag; Lundström, Patrik; Camilloni, Carlo; Evenäs, Johan; Akke, Mikael; Vendruscolo, Michele

    2016-01-12

    Calmodulin is a two-domain signaling protein that becomes activated upon binding cooperatively two pairs of calcium ions, leading to large-scale conformational changes that expose its binding site. Despite significant advances in understanding the structural biology of calmodulin functions, the mechanistic details of the conformational transition between closed and open states have remained unclear. To investigate this transition, we used a combination of molecular dynamics simulations and nuclear magnetic resonance (NMR) experiments on the Ca(2+)-saturated E140Q C-terminal domain variant. Using chemical shift restraints in replica-averaged metadynamics simulations, we obtained a high-resolution structural ensemble consisting of two conformational states and validated such an ensemble against three independent experimental data sets, namely, interproton nuclear Overhauser enhancements, (15)N order parameters, and chemical shift differences between the exchanging states. Through a detailed analysis of this structural ensemble and of the corresponding statistical weights, we characterized a calcium-mediated conformational transition whereby the coordination of Ca(2+) by just one oxygen of the bidentate ligand E140 triggers a concerted movement of the two EF-hands that exposes the target binding site. This analysis provides atomistic insights into a possible Ca(2+)-mediated activation mechanism of calmodulin that cannot be achieved from static structures alone or from ensemble NMR measurements of the transition between conformations.

  15. Vanadate affects nuclear division and induces aberrantly-shaped cells during subsequent cytokinesis in Tetrahymena

    DEFF Research Database (Denmark)

    Nilsson, Jytte R.

    1999-01-01

    cellebiology,endocytosis,monsters,nuclear elongation,sodium orthovanadate,Tetrahymena pyriformis,proliferation......cellebiology,endocytosis,monsters,nuclear elongation,sodium orthovanadate,Tetrahymena pyriformis,proliferation...

  16. Abatement of morphine-induced slowing in gastrointestinal transit by Dai-kenchu-to, a traditional Japanese herbal medicine.

    Science.gov (United States)

    Nakamura, Tomonori; Sakai, Akiko; Isogami, Issei; Noda, Kazuhiro; Ueno, Koichi; Yano, Shingo

    2002-02-01

    As a way of alleviating severe constipation in cancer patients taking morphine to relieve pain, effects of Dai-kenchu-to (DKT), a traditional Japanese herbal medicine (Kampo medicine), on gastrointestinal transit in mice or on the isolated guinea pig ileum were studied in special reference to morphine. Without altering the anti-nociceptive effect of morphine, DKT was significantly effective against morphine-induced disorder of gastrointestinal transit in mice as assessed by the charcoal meal test for the intestine and measurement of transit time for the colon tract. The results of in vitro studies with guinea pig ileum suggest that abatement of morphine-induced disorder of transit by DKT is caused by both moderate contraction of morphine-treated longitudinal muscle and relaxation of morphine-induced tonic contraction of circular muscle.

  17. Pressure-induced phase transition in Bi2Se3 at 3 GPa: electronic topological transition or not?

    Science.gov (United States)

    Bera, Achintya; Pal, Koushik; Muthu, D V S; Waghmare, U V; Sood, A K

    2016-03-16

    In recent years, a low pressure transition around P3 GPa exhibited by the A2B3-type 3D topological insulators is attributed to an electronic topological transition (ETT) for which there is no direct evidence either from theory or experiments. We address this phase transition and other transitions at higher pressure in bismuth selenide (Bi2Se3) using Raman spectroscopy at pressure up to 26.2 GPa. We see clear Raman signatures of an isostructural phase transition at P2.4 GPa followed by structural transitions at ∼ 10 GPa and 16 GPa. First-principles calculations reveal anomalously sharp changes in the structural parameters like the internal angle of the rhombohedral unit cell with a minimum in the c/a ratio near P3 GPa. While our calculations reveal the associated anomalies in vibrational frequencies and electronic bandgap, the calculated Z2 invariant and Dirac conical surface electronic structure remain unchanged, showing that there is no change in the electronic topology at the lowest pressure transition.

  18. Order-disorder phase transition and stress-induced diffusion in Au-Cu

    Science.gov (United States)

    Hennig, John; Mari, Daniele; Schaller, Robert

    2009-04-01

    Isothermal mechanical spectroscopy by means of a forced torsion pendulum (measuring internal friction/mechanical loss) was used to study the interplay of long-range atomic order and stress-induced diffusion (Zener relaxation) in Au57%Cu43% . Our results show that the relaxation strength of stress-induced diffusion exhibits the typical Curie-Weiss-type behavior in the disordered solid solution and then gradually goes to zero below the critical temperature marking the phase transition to the long-range-ordered AuCu II phase. The breakdown of the relaxation peak reflects the kinetics of the ordering process. The diffusion data were used to establish the transformation time vs temperature (TTT) diagram of the phase transformation.

  19. Nuclear spectroscopy

    CERN Document Server

    Ajzenberg-Selove, Fay

    1960-01-01

    Nuclear Spectroscopy, Part B focuses on the ways in which experimental data may be analyzed to furnish information about nuclear parameters and nuclear models in terms of which the data are interpreted.This book discusses the elastic and inelastic potential scattering amplitudes, role of beta decay in nuclear physics, and general selection rules for electromagnetic transitions. The nuclear shell model, fundamental coupling procedure, vibrational spectra, and empirical determination of the complex potential are also covered. This publication is suitable for graduate students preparing for exper

  20. Surface transition on ice induced by the formation of a grain boundary.

    Directory of Open Access Journals (Sweden)

    Christian Pedersen

    Full Text Available Interfaces between individual ice crystals, usually referred to as grain boundaries, play an important part in many processes in nature. Grain boundary properties are, for example, governing the sintering processes in snow and ice which transform a snowpack into a glacier. In the case of snow sintering, it has been assumed that there are no variations in surface roughness and surface melting, when considering the ice-air interface of an individual crystal. In contrast to that assumption, the present work suggests that there is an increased probability of molecular surface disorder in the vicinity of a grain boundary. The conclusion is based on the first detailed visualization of the formation of an ice grain boundary. The visualization is enabled by studying ice crystals growing into contact, at temperatures between -20°C and -15°C and pressures of 1-2 Torr, using Environmental Scanning Electron Microscopy. It is observed that the formation of a grain boundary induces a surface transition on the facets in contact. The transition does not propagate across facet edges. The surface transition is interpreted as the spreading of crystal dislocations away from the grain boundary. The observation constitutes a qualitatively new finding, and can potentially increase the understanding of specific processes in nature where ice grain boundaries are involved.

  1. Pressure-induced phase transition and structural properties of CrO2

    Science.gov (United States)

    Wu, H. Y.; Chen, Y. H.; Deng, C. R.; Su, X. F.

    2012-08-01

    The structural properties and pressure-induced phase transitions of CrO2 have been investigated using the pseudopotential plane-wave method based on the density functional theory (DFT). The rutile-type (P42/mnm), CaCl2-type (Pnnm), pyrite-type (Pā3), and CaF2-type (Fm-3m) phases of CrO2 have been considered. The structural properties such as lattice parameters, bulk moduli and its pressure derivative are consistent with the available experimental data. The second-order phase-transition pressure of CrO2 from the rutile phase to CaCl2 phase is 10.9 GPa, which is in good agreement with the experimental result. The sequence of these phases is rutile-type → CaCl2-type → pyrite-type → CaF2-type with the phase-transition pressures 10.9, 23.9, and 144.5 GPa, respectively. The equation of state of different phases has also been presented. It is more difficult to compress with the increase of pressure for different phases of CrO2.

  2. Deferasirox induces mesenchymal-epithelial transition in crocidolite-induced mesothelial carcinogenesis in rats.

    Science.gov (United States)

    Nagai, Hirotaka; Okazaki, Yasumasa; Chew, Shan Hwu; Misawa, Nobuaki; Yasui, Hiroyuki; Toyokuni, Shinya

    2013-11-01

    Asbestos was used worldwide in huge quantities in the past century. However, because of the unexpected carcinogenicity to mesothelial cells with an extremely long incubation period, many countries face this long-lasting social problem. Mesothelioma is often diagnosed in an advanced stage, for which no effective therapeutic protocols are yet established. We previously reported on the basis of animal experiments that the major pathology in asbestos-induced mesothelial carcinogenesis is local iron overload. Here, we undertook to find an effective strategy to prevent, delay, or lower the malignant potential of mesothelioma during asbestos-induced carcinogenesis. We used intraperitoneal injections of crocidolite to rats. We carried out a 16-week study to seek the maximal-tolerated intervention for iron reduction via oral deferasirox administration or intensive phlebotomy. Splenic iron deposition was significantly decreased with either method, and we found that Perls' iron staining in spleen is a good indicator for iron reduction. We injected a total of 10 mg crocidolite at the age of six weeks, and the preventive measures were via repeated oral administration of 25 to 50 mg/kg/d deferasirox or weekly to bimonthly phlebotomy of 4 to 10 mL/kg/d. The animals were observed until 110 weeks. Deferasirox administration significantly increased the fraction of less malignant epithelioid subtype. Although we found a slightly prolonged survival in deferasirox-treated female rats, larger sample size and refinement of the current protocol are necessary to deduce the cancer-preventive effects of deferasirox. Still, our results suggest deferasirox serves as a potential preventive strategy in people already exposed to asbestos via iron reduction.

  3. High-Spin Isomeric States in Nuclear Reactions Induced by He Isotopes

    Science.gov (United States)

    Chuvilskaya, Tatjana; Shirokova, Alla

    2010-11-01

    The high-spin states production in nuclear reactions is reviewed. The analysis of various experiments, our estimates and calculations reveal that in different compound nucleus energy regions maximal relative yield of high-spin states can be realized by different projectiles: at low energies -- by neutrons, in ˜ 20 -- 50 MeV region -- by α-particles, at higher energies -- by heavy ions. It was predicted [1] that there are energy ranges in which neutron-rich radioactive ions (^6,8He, for example) are favorable. σm/σg (the ratio between the yields of high-spin Jm and low-spin Jg metastable states of a nucleus in one and the same reaction) e.g. the isomeric cross-section ratio is a very good indicator of high-spin states production capability of a nuclear reaction. These experiments demonstrate that maximal values of isomeric cross-section ratios (up to 30) are obtained in α-particle induced reactions. Experiment with ^6He beam [2] confirms the predictions of the work [1] concerning the prospects of neutron-rich radioactive-ion beams in high-spin states population. The results of calculations of the isomeric cross section ratios using the code EMPIRE-II-18 approach to statistical theory of nuclear reactions demonstrate rather good agreement with the experimental data. Due to that these prediction power of these calculation is confirmed. The results of widespread calculations of the isomeric cross-section ratios of the reactions with ^6,8He are presented. [1] T.V.Chvilskaya et al., AIP-Conference Proceedings ENAM-98 1998. V. 455. P. 482. [2] P.A.DeYoung et al., Phys.Rev.C. 2000. V. 62. P.047601.

  4. Analysis of factors related to man-induced hazard for nuclear facilities

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Young Soon; Jung, Jea Hee; Lee, Keun O; Son, Ki Sang; Wang, Sang Chul; Lee, Chang Jin; Ku, Min Ho; Park, Nam Young [Seoul National Univ. of Technology, Seoul (Korea, Republic of)

    2003-03-15

    This study is to show a guide for installing hazardous facilities adjoined atomic power plant after finding out how much these facilities could impact to the atomic plant. Nuclear power plant is an important facility which is closely connected with public life, industrial activity, and the conduct of public business, so it should not be damaged. Therefore, if there are hazardous and harmful facilities near the plant, then they must be evaluated by the size, the type, and the shape. First of all, any factors that could cause man induced accident must be investigated. And they must be exactly evaluated from how much it will damage the plant facilities. The purpose of this study is to set a technical standard for the installation of these facilities by evaluating the man induced accident. Also, it is to make out the evaluation methods by investigating the hazardous facilities which are placed near the plant. Our country is now using CFR standard : reg. guide and IAEA safety series. However, not only the standard of technology which is related to man induced accident but also the evaluation methods for facilities are not yet layed down. As It was mentioned above, we should evaluate these facilities adequately, and these methods must be made out.

  5. Transition-Edge Sensors for Particle Induced X-ray Emission Measurements

    CERN Document Server

    Palosaari, M R J; Julin, J; Laitinen, M; Napari, M; Sajavaara, T; Doriese, W B; Fowler, J; Reintsema, C; Swetz, D; Schmidt, D; Ullom, J; Maasilta, I J

    2013-01-01

    In this paper we present a new measurement setup, where a transitionedge sensor detector array is used to detect X-rays in particle induced X-ray emission measurements with a 2 MeV proton beam. Transition-edge sensors offer orders of magnitude improvement in energy resolution compared to conventional silicon or germanium detectors, making it possible to recognize spectral lines in materials analysis that have previously been impossible to resolve, and to get chemical information from the elements. Our sensors are cooled to the operation temperature (65 mK) with a cryogen-free adiabatic demagnetization refrigerator, which houses a specially designed X-ray snout that has a vacuum tight window to couple in the radiation. For the best pixel, the measured instrumental energy resolution was 3.06 eV full width at half maximum at 5.9 keV.We discuss the current status of the project, benefits of transition-edge sensors when used in particle induced X-ray emission spectroscopy, and the results from the first measuremen...

  6. Electric field-induced superconducting transition of insulating FeSe thin film at 35 K.

    Science.gov (United States)

    Hanzawa, Kota; Sato, Hikaru; Hiramatsu, Hidenori; Kamiya, Toshio; Hosono, Hideo

    2016-04-12

    It is thought that strong electron correlation in an insulating parent phase would enhance a critical temperature (Tc) of superconductivity in a doped phase via enhancement of the binding energy of a Cooper pair as known in high-Tc cuprates. To induce a superconductor transition in an insulating phase, injection of a high density of carriers is needed (e.g., by impurity doping). An electric double-layer transistor (EDLT) with an ionic liquid gate insulator enables such a field-induced transition to be investigated and is expected to result in a high Tc because it is free from deterioration in structure and carrier transport that are in general caused by conventional carrier doping (e.g., chemical substitution). Here, for insulating epitaxial thin films (∼10 nm thick) of FeSe, we report a high Tc of 35 K, which is 4× higher than that of bulk FeSe, using an EDLT under application of a gate bias of +5.5 V. Hall effect measurements under the gate bias suggest that highly accumulated electron carrier in the channel, whose area density is estimated to be 1.4 × 10(15) cm(-2) (the average volume density of 1.7 × 10(21) cm(-3)), is the origin of the high-Tc superconductivity. This result demonstrates that EDLTs are useful tools to explore the ultimate Tc for insulating parent materials.

  7. Investigations of nuclear structure and nuclear reactions induced by complex projectiles. Progress report, September 1, 1991--August 31, 1992

    Energy Technology Data Exchange (ETDEWEB)

    Sarantites, D.G.

    1992-12-01

    The research program described touches five areas of nuclear physics: nuclear structure studies at high spin (hyperdeformation in the mass A {approx_equal} 182 region, structure of {sup 182}Hg and {sup 182}Au at high spin, a highly deformed band in {sup 136}Pm and the anomalous h{sub 11/2} proton crossing in the A{approximately}135 superdeformed region), studies at the interface between structure and reactions (population of entry states in heavy-ion fusion reactions, nuclear structure effects in proton evaporation spectra, nuclear structure- dependent entry state population by total spectroscopy, entrance channel effects in fusion near the barrier, lifetimes of subbarrier {alpha} particles by the atomic clock method), production and study of hot nuclei (the statistical model evaporation code EVAP, statistical emission of deuterons and tritons from highly excited compound nuclei, heavy-fragment emission as a probe of the thermal properties of highly excited compound nuclei, use of incoming-wave boundary condition transmission coefficients in the statistical model: implications in the particle evaporation spectra, study of transparency in the optical model), reaction mechanism studies (binary character of highly dissipative {sup 209}Bi + {sup 136}Xe collisions at E/A=28.2 MeV), and development and use of novel techniques and instrumentation in these areas of research (including a 4{pi} channel selection device, a novel x-ray detector, and a simple channel-selecting detector).

  8. Investigations of nuclear structure and nuclear reactions induced by complex projectiles. [Dept. of Chemistry, Washington Univ. , St. Louis, Mo

    Energy Technology Data Exchange (ETDEWEB)

    Sarantites, D.G.

    1992-01-01

    The research program described touches five areas of nuclear physics: nuclear structure studies at high spin (hyperdeformation in the mass A [approx equal] 182 region, structure of [sup 182]Hg and [sup 182]Au at high spin, a highly deformed band in [sup 136]Pm and the anomalous h[sub 11/2] proton crossing in the A[approximately]135 superdeformed region), studies at the interface between structure and reactions (population of entry states in heavy-ion fusion reactions, nuclear structure effects in proton evaporation spectra, nuclear structure- dependent entry state population by total spectroscopy, entrance channel effects in fusion near the barrier, lifetimes of subbarrier [alpha] particles by the atomic clock method), production and study of hot nuclei (the statistical model evaporation code EVAP, statistical emission of deuterons and tritons from highly excited compound nuclei, heavy-fragment emission as a probe of the thermal properties of highly excited compound nuclei, use of incoming-wave boundary condition transmission coefficients in the statistical model: implications in the particle evaporation spectra, study of transparency in the optical model), reaction mechanism studies (binary character of highly dissipative [sup 209]Bi + [sup 136]Xe collisions at E/A=28.2 MeV), and development and use of novel techniques and instrumentation in these areas of research (including a 4[pi] channel selection device, a novel x-ray detector, and a simple channel-selecting detector).

  9. From nuclear power to coal power: Aerosol-induced health and radiative effects

    Science.gov (United States)

    Mielonen, Tero; Laakso, Anton; Karhunen, Anni; Kokkola, Harri; Partanen, Antti-Ilari; Korhonen, Hannele; Romakkaniemi, Sami; Lehtinen, Kari E. J.

    2015-12-01

    We have investigated what would be the climate and PM-induced air quality consequences if all nuclear reactors worldwide were closed down and replaced by coal combustion. In a way, this presents a "worst-case scenario" since less polluting energy sources are available. We studied simultaneously the radiative and health effects of coal power emissions using a global 3-D aerosol-climate model (ECHAM-HAMMOZ). This approach allowed us to estimate the effects of a major global energy production change from low carbon source to a high carbon one using detailed spatially resolved population density information. We included the radiative effects of both CO2 and PM2.5 but limited the study of health effects to PM2.5 only. Our results show that the replacement of nuclear power with coal power would have globally caused an average of 150,000 premature deaths per year during the period 2005-2009 with two thirds of them in Europe. For 37 years the aerosol emissions from the additional coal power plants would cool the climate but after that the accumulating CO2 emissions would accelerate the warming of the climate.

  10. Transfer-induced fission in inverse kinematics: Impact on experimental and evaluated nuclear data bases

    Science.gov (United States)

    Farget, F.; Caamaño, M.; Ramos, D.; Rodrıguez-Tajes, C.; Schmidt, K.-H.; Audouin, L.; Benlliure, J.; Casarejos, E.; Clément, E.; Cortina, D.; Delaune, O.; Derkx, X.; Dijon, A.; Doré, D.; Fernández-Domınguez, B.; Gaudefroy, L.; Golabek, C.; Heinz, A.; Jurado, B.; Lemasson, A.; Paradela, C.; Roger, T.; Salsac, M. D.; Schmitt, C.

    2015-12-01

    Inverse kinematics is a new tool to study nuclear fission. Its main advantage is the possibility to measure with an unmatched resolution the atomic number of fission fragments, leading to new observables in the properties of fission-fragment distributions. In addition to the resolution improvement, the study of fission based on nuclear collisions in inverse kinematics beneficiates from a larger view with respect to the neutron-induced fission, as in a single experiment the number of fissioning systems and the excitation energy range are widden. With the use of spectrometers, mass and kinetic-energy distributions may now be investigated as a function of the proton and neutron number sharing. The production of fissioning nuclei in transfer reactions allows studying the isotopic yields of fission fragments as a function of the excitation energy. The higher excitation energy resulting in the fusion reaction leading to the compound nucleus 250Cf at an excitation energy of 45MeV is also presented. With the use of inverse kinematics, the charge polarisation of fragments at scission is now revealed with high precision, and it is shown that it cannot be neglected, even at higher excitation energies. In addition, the kinematical properties of the fragments inform on the deformation configuration at scission.

  11. A nuclear import inhibitory peptide ameliorates the severity of Cholecystokinin-induced acute pancreatitis

    Institute of Scientific and Technical Information of China (English)

    Tamás Letoha; István Krizbai; Imre Boros; Ern(o) Duda; Erzsébet Kusz; Botond Penke; Csaba Somlai; Tamás Takács; Annamária Szabolcs; Katalin Jármay; Zoltán Rakonczay Jr; Péter Hegyi; Ilona Varga; József Kaszaki

    2005-01-01

    AIM: To assess the effect of our novel cell-permeable nuclear factor-kappaB (NF-κB) inhibitor peptide PN50 in an experimental model of acute pancreatitis. PN50 was produced by conjugating the cell-penetrating penetratin peptide with the nuclear localization signal of the NF-κB p50 subunit.METHODS: Pancreatitis was induced in male Wistar rats by administering 2×100 μg/kg body weight of cholecystokininoctapeptide (CCK) intraperitoneally (IP) at an interval of 1 h. PN50-treated animals received 1 mg/kg of PN50 IP 30 min before or after the CCK injections. The animals were sacrificed 4 h after the first injection of CCK.RESULTS: All the examined laboratory (the pancreatic weight/body weight ratio, serum amylase activity,pancreatic levels of TNF-α and IL-6, degree of lipid peroxidation, reduced glutathione levels, NF-κB binding activity, pancreatic and lung myeloperoxidase activity) and morphological parameters of the disease were improved before and after treatment with the PN50 peptide.According to the histological findings, PN50 protected the animals against acute pancreatitis by favoring the induction of apoptotic, as opposed to necrotic acinar cell death associated with severe acute pancreatitis.CONCLUSION: Our study implies that reversible inhibitors of stress-responsive transcription factors like NF-κB might be clinically useful for the suppression of the severity of acute pancreatitis.

  12. Pion-induced production of the $Z_c(3900)$ off nuclear target

    CERN Document Server

    Huang, Yin; Liu, Xiang; Zhang, Hong Fei; Xie, Ju Jun; Chen, Xu Rong

    2015-01-01

    We investigate the possibility to study the charmonium-like state $Z_c(3900)$ through the pion-induced production off nuclear target. By using high-energy pion beam, the $Z_c(3900)$ can be produced off proton or nucleus though the Primakoff effect. The production amplitude is calculated in an effective Lagrangian approach combined with the vector dominance model. The total cross sections of the $p(\\pi^-, Z^-_c(3900))$ and $p(\\pi^-, Z^-_c(3900)\\to J/\\psi\\pi^-)$ reactions are calculated, which order of magnitude is about 0.1 and 0.01nb, respectively, with an assumption of branch ratio 10\\% for the $Z_c(3900)$ decay in $J/\\psi\\pi$ channel. If proton target is replaced by nuclear target, the production of the $Z_c(3900)$ enhances obviously. The predicted total cross sections for the $A(\\pi^-, Z^-_c(3900))$ and $A(\\pi^-, Z^-_c(3900)\\to J/\\psi\\pi^-)$ reactions with $A=^{12}$C or $^{208}$Pb are on the order of magnitude of 100 and 10 nb, respectively, which is about one thousand times larger than the cross sections ...

  13. Transfer-induced fission in inverse kinematics: Impact on experimental and evaluated nuclear data bases

    Energy Technology Data Exchange (ETDEWEB)

    Farget, F.; Schmidt, K.H.; Clement, E.; Delaune, O.; Derkx, X.; Dijon, A.; Golabek, C.; Lemasson, A.; Roger, T.; Schmitt, C. [CEA/DSM-CNRS/IN2P3, GANIL, Caen (France); Caamano, M.; Ramos, D.; Benlliure, J.; Cortina, D.; Fernandez-Dominguez, B.; Paradela, C. [Universidade de Santiago de Compostela, Santiago de Compostela (Spain); Rodriguez-Tajes, C. [CEA/DSM-CNRS/IN2P3, GANIL, Caen (France); Universidade de Santiago de Compostela, Santiago de Compostela (Spain); Audouin, L. [Universite Paris-Sud 11, CNRS/IN2P3, Institut de Physique Nucleaire, Orsay (France); Casarejos, E. [Universidade de Vigo, Vigo (Spain); Dore, D.; Salsac, M.D. [Centre de Saclay, CEA, Irfu, Gif-sur-Yvette (France); Gaudefroy, L. [CEA DAM Ile-de-France, BP 12, Bruyeres-le-Chatel (France); Heinz, A. [Chalmers Tekniska Hoegskola, Fundamental Fysik, Goeteborg (Sweden); Jurado, B. [Universite Bordeaux, CENBG, UMR 5797 CNRS/IN2P3, Gradignan (France)

    2015-12-15

    Inverse kinematics is a new tool to study nuclear fission. Its main advantage is the possibility to measure with an unmatched resolution the atomic number of fission fragments, leading to new observables in the properties of fission-fragment distributions. In addition to the resolution improvement, the study of fission based on nuclear collisions in inverse kinematics beneficiates from a larger view with respect to the neutron-induced fission, as in a single experiment the number of fissioning systems and the excitation energy range are widden. With the use of spectrometers, mass and kinetic-energy distributions may now be investigated as a function of the proton and neutron number sharing. The production of fissioning nuclei in transfer reactions allows studying the isotopic yields of fission fragments as a function of the excitation energy. The higher excitation energy resulting in the fusion reaction leading to the compound nucleus {sup 250}Cf at an excitation energy of 45MeV is also presented. With the use of inverse kinematics, the charge polarisation of fragments at scission is now revealed with high precision, and it is shown that it cannot be neglected, even at higher excitation energies. In addition, the kinematical properties of the fragments inform on the deformation configuration at scission. (orig.)

  14. The use of low energy, ion induced nuclear reactions for proton radiotherapy applications

    Energy Technology Data Exchange (ETDEWEB)

    Horn, K.M.; Doyle, B. [Sandia National Labs., Albuquerque, NM (United States); Segal, M.N. [Univ. of New Mexico Medical School, Albuquerque, NM (United States). Dept. of Otolaryngology; Hamm, R.W. [Accsys Technology Inc., Pleasanton, CA (United States); Adler, R.J. [North Star Research Corp., Albuquerque, NM (United States); Glatstein, E. [Univ. of Texas Southwest Medical Center, Dallas, TX (United States)

    1995-04-01

    Medical radiotherapy has traditionally relied upon the use of external photon beams and internally implanted radioisotopes as the chief means of irradiating tumors. However, advances in accelerator technology and the exploitation of novel means of producing radiation may provide useful alternatives to some current modes of medical radiation delivery with reduced total dose to surrounding healthy tissue, reduced expense, or increased treatment accessibility. This paper will briefly overview currently established modes of radiation therapy, techniques still considered experimental but in clinical use, innovative concepts under study that may enable new forms of treatment or enhance existing ones. The potential role of low energy, ion-induced nuclear reactions in radiotherapy applications is examined specifically for the 650 keV d({sup 3}He,p){sup 4}He nuclear reaction. This examination will describe the basic physics associated with this reaction`s production of 17.4 MeV protons and the processes used to fabricate the necessary materials used in the technique. Calculations of the delivered radiation dose, heat generation, and required exposure times are presented. Experimental data are also presented validating the dose calculations. The design of small, lower cost ion accelerators, as embodied in `nested`-tandem and radio frequency quadrupole accelerators is examined, as is the potential use of high-output {sup 3}He and deuterium ion sources. Finally, potential clinical applications are discussed in terms of the advantages and disadvantages of this technique with respect to current radiotherapy methods and equipment.

  15. The effects of solar-geomagnetically induced currents on electrical systems in nuclear power stations

    Energy Technology Data Exchange (ETDEWEB)

    Subudhi, M. [Brookhaven National Lab., Upton, NY (United States); Carroll, D.P. [Florida Univ., Gainesville, FL (United States); Kasturi, S. [MOS, Inc., Melville, NY (United States)

    1994-01-01

    This report presents the results of a study to evaluate the potential effects of geomagnetically induced currents (GICs) caused by the solar disturbances on the in-plant electrical distribution system and equipment in nuclear power stations. The plant-specific electrical distribution system for a typical nuclear plant is modeled using the ElectroMagnetic Transient Program (EMTP). The computer model simulates online equipment and loads from the station transformer in the switchyard of the power station to the safety-buses at 120 volts to which all electronic devices are connected for plant monitoring. The analytical model of the plant`s electrical distribution system is studied to identify the transient effects caused by the half-cycle saturation of the station transformers due to GIC. This study provides results of the voltage harmonics levels that have been noted at various electrical buses inside the plant. The emergency circuits appear to be more susceptible to high harmonics due to the normally light load conditions. In addition to steady-state analysis, this model was further analyzed simulating various plant transient conditions (e.g., loss of load or large motor start-up) occurring during GIC events. Detail models of the plant`s protective relaying system employed in bus transfer application were included in this model to study the effects of the harmonic distortion of the voltage input. Potential harmonic effects on the uniterruptable power system (UPS) are qualitatively discussed as well.

  16. Magnon-induced nuclear relaxation in the quantum critical region of a Heisenberg linear chain

    Science.gov (United States)

    Hoch, M. J. R.

    2017-07-01

    The low-temperature properties of spin-1/2 one-dimensional (1D) Heisenberg antiferromagnetic (HAF) chains which have relatively small exchange couplings between the spins can be tuned using laboratory-scale magnetic fields. Magnetization measurements, made as a function of temperature, provide phase diagrams for these systems and establish the quantum critical point (QCP). The evolution of the spin dynamics behavior with temperature and applied field in the quantum critical (QC) region, near the QCP, is of particular interest and has been experimentally investigated in a number of 1D HAFs using neutron scattering and nuclear magnetic resonance as the preferred techniques. In the QC phase both quantum and thermal spin fluctuations are present. As a result of extended spin correlations in the chains, magnon excitations are important at finite temperatures. An expression for the NMR spin-lattice relaxation rate 1 /T1 of probe nuclei in the QC phase of 1D HAFs is obtained by considering Raman scattering processes which induce nuclear spin flips. The relaxation rate expression, which involves the temperature and the chemical potential, predicts scaling behavior of 1 /T1 consistent with recent experimental findings for quasi-1D HAF systems. A simple relationship between 1 /T1 and the deviation of the magnetization from saturation (MS-M ) is predicted for the QC region.

  17. Ghrelin improves delayed gastrointestinal transit in alloxan-induced diabetic mice

    Institute of Scientific and Technical Information of China (English)

    Wen-Cai Qiu; Zhi-Gang Wang; Ran Lv; Wei-Gang Wang; Xiao-Dong Han; Jun Yan; Yu Wang; Qi Zheng; Kai-Xing Ai

    2008-01-01

    AIM: To investigate the effects of ghrelin on delayed gastrointestinal transit in alloxan-induced diabetic mice.METHODS: A diabetic mouse model was established by intraperitoneal injection with alloxan.Mice were randomized into two main groups: normal mice group and diabetic mice group treated with ghrelin at doses of 0, 20, 50, 100 and 200 μg/kg ip.Gastric emptying (GE), intestinal transit (IT), and colonic transit (CT)were studied in mice after they had a phenol red meal following injection of ghrelin.Based on the most effective ghrelin dosage, atropine was given at 1 mg/kg 15 min before the ghrelin injection for each measurement.The mice in each group were sacrificed 20 min later and their stomachs, intestines, and colons were harvested immediately.The amount of phenol red was measured.Percentages of GE, IT, and CT were calculated.RESULTS: Percentages of GE, IT, and CT were significantly decreased in diabetic mice as compared to control mice (22.9±1.4 vs 28.1±1.3, 33.5±1.2 vs 43.2±1.9, 29.5±1.9 vs 36.3±1.6, P < 0.05).In the diabetic mice, ghrelin improved both GE and IT, but not CT.The most effective dose of ghrelin was 100 μg/kg and atropine blocked the prokinetic effects of ghrelin on GE and IT.CONCLUSION: Ghrelin accelerates delayed GE and IT but has no effect on CT in diabetic mice.Ghrelin may exert its prokinetic effects via the cholinergic pathway in the enteric nervous system, and therefore has therapeutic potential for diabetic patients with delayed upper gastrointestinal transit.

  18. Ghrelin improves delayed gastrointestinal transit in alloxan-induced diabetic mice.

    Science.gov (United States)

    Qiu, Wen-Cai; Wang, Zhi-Gang; Lv, Ran; Wang, Wei-Gang; Han, Xiao-Dong; Yan, Jun; Wang, Yu; Zheng, Qi; Ai, Kai-Xing

    2008-04-28

    To investigate the effects of ghrelin on delayed gastrointestinal transit in alloxan-induced diabetic mice. A diabetic mouse model was established by intraperitoneal injection with alloxan. Mice were randomized into two main groups: normal mice group and diabetic mice group treated with ghrelin at doses of 0, 20, 50, 100 and 200 mug/kg ip. Gastric emptying (GE), intestinal transit (IT), and colonic transit (CT) were studied in mice after they had a phenol red meal following injection of ghrelin. Based on the most effective ghrelin dosage, atropine was given at 1 mg/kg 15 min before the ghrelin injection for each measurement. The mice in each group were sacrificed 20 min later and their stomachs, intestines, and colons were harvested immediately. The amount of phenol red was measured. Percentages of GE, IT, and CT were calculated. Percentages of GE, IT, and CT were significantly decreased in diabetic mice as compared to control mice (22.9 +/- 1.4 vs 28.1 +/- 1.3, 33.5 +/- 1.2 vs 43.2 +/- 1.9, 29.5 +/- 1.9 vs 36.3 +/- 1.6, P CT. The most effective dose of ghrelin was 100 mug/kg and atropine blocked the prokinetic effects of ghrelin on GE and IT. Ghrelin accelerates delayed GE and IT but has no effect on CT in diabetic mice. Ghrelin may exert its prokinetic effects via the cholinergic pathway in the enteric nervous system, and therefore has therapeutic potential for diabetic patients with delayed upper gastrointestinal transit.

  19. Hindlimb unloading-induced muscle atrophy and phenotype transition is attenuated in Smad3+/- mice

    Science.gov (United States)

    Chen, X. P.; Zhang, P.; Liu, S. H.; Wang, F.; Ge, X.; Wu, Y.; Fan, M.

    Currently it has been well defined that the microgravity-induced muscle disuse characterized by atrophy and slow-to-fast phenotype transition of the postural muscles such as soleus muscle but the basic mechanism underlying the atrophy and phenotype transition of soleus muscle is still unclear To investigate the developmental mechanisms of muscle atrophy and its phenotype transition under microgravity the soleus muscle of Smad3 and Smad3 - mice after 14 days hindlimb unloading was examined Using histology and immunohistochemistry assay we found that the soleus muscle volume and fiber number appeared a remarkable increases in Smad3 - mice compared to those in Smad3 control In addition Western blot analysis showed that the expression level of myosin heavy chain MHC -slow myofiber specific protein in soleus muscle was visibly higher in Smad3 - mice than in Smad3 mice In contrast the expression level of MHC-fast myofiber specific protein in soleus muscle was visibly lower in Smad3 - mice than in Smad3 mice Furthermore RT-PCR revealed that the expression of Smad3 and myogenic regulatory factor MRF mRNA was inversely regulated Finally we determined that either Smad3 mRNA or Smad3 protein were selectively distributed in quiescent satellite cells in vivo and in reserve cells in vitro Therefore our findings suggested that Smad3 might be a key transcriptional factor for soleus muscle atrophy and slow-to-fast phenotype transition of the slow muscle under microgravity In the future an agent that regulates Smad3 expression may be used to prevent

  20. Calcium citrate improves the epithelial-to-mesenchymal transition induced by acidosis in proximal tubular cells

    Directory of Open Access Journals (Sweden)

    Maria José Rodriguez Cabalgante

    2012-12-01

    Full Text Available INTRODUCTION: Epithelial-to-mesenchymal transition (EMT is a key event in renal fibrosis. The aims of the study were to evaluate acidosis induced EMT, transforming-growth-factor (TGF β1 role and citrate effect on it. METHODS: HK2 cells (ATCC 2290 were cultured in DMEM/HAM F12 medium, pH 7.4. At 80% confluence, after 24 hr under serum free conditions, cells were distributed in three groups (24 hours: A Control: pH 7.4, B Acidosis: pH 7.0 and C Calcium citrate (0.2 mmol/L + pH 7.0. Change (Δ of intracellular calcium concentration, basal and after Angiotensin II (10-6M exposition, were measured to evaluate cellular performance. EMT was evaluated by the expression of α-smooth muscle actin (α-SMA and E-cadherin by immunocytochemistry and/or Western blot. TGF-β1 secretion was determined by ELISA in cell supernatant. RESULTS: At pH 7.0 HK2 cells significantly reduced E-cadherin and increased α-SMA expression (EMT. Supernatant TGF-β1 levels were higher than in control group. Calcium citrate decreased acidosis induced EMT and improved cells performance, without reduction of TGF-β production. CONCLUSIONS: Acidosis induces EMT and secretion of TGF-β1 in tubular proximal cells in culture and citrate improves cellular performance and ameliorates acidosis induced EMT.

  1. Quercetin induces human colon cancer cells apoptosis by inhibiting the nuclear factor-kappa B Pathway.

    Science.gov (United States)

    Zhang, Xiang-An; Zhang, Shuangxi; Yin, Qing; Zhang, Jing

    2015-01-01

    Quercetin can inhibit the growth of cancer cells with the ability to act as chemopreventers. Its cancer-preventive effect has been attributed to various mechanisms, including the induction of cell-cycle arrest and/or apoptosis as well as the antioxidant functions. Nuclear factor kappa-B (NF-κB) is a signaling pathway that controls transcriptional activation of genes important for tight regulation of many cellular processes and is aberrantly expressed in many types of cancer. Inhibitors of NF-κB pathway have shown potential anti-tumor activities. However, it is not fully elucidated in colon cancer. In this study, we demonstrate that quercetin induces apoptosis in human colon cancer CACO-2 and SW-620 cells through inhibiting NF-κB pathway, as well as down-regulation of B-cell lymphoma 2 and up-regulation of Bax, thus providing basis for clinical application of quercetin in colon cancer cases.

  2. Search for Perturbations of Nuclear Decay Rates Induced by Reactor Electron Antineutrinos

    CERN Document Server

    Barnes, V E; Bryan, C D; Cinko, N; Deichert, G G; Gruenwald, J T; Heim, J M; Kaplan, H B; LaZur, R; Neff, D; Nistor, J M; Sahelijo, N; Fischbach, E

    2016-01-01

    We report the results of an experiment conducted near the High Flux Isotope Reactor of Oak Ridge National Laboratory, designed to address the question of whether a flux of reactor-generated electron antineutrinos can alter the rates of weak nuclear interaction-induced decays for Mn-54, Na-22, and Co-60. This experiment, while quite sensitive, cannot exclude perturbations less than one or two parts in $10^4$ in $\\beta$ decay (or electron capture) processes, in the presence of an antineutrino flux of $3\\times 10^{12}$ cm$^{-2}$ s$^{-1}$. The present experimental methods are applicable to a wide range of isotopes. Improved sensitivity in future experiments may be possible if we can understand and reduce the dominant systematic uncertainties.

  3. Activation cross sections of proton induced nuclear reactions on ytterbium up to 70 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Tarkanyi, F. [Institute of Nuclear Research of the Hungarian Academy of Sciences (ATOMKI), 4026 Debrecen, Bem ter 18/c (Hungary); Hermanne, A. [Cyclotron Laboratory, Vrije Universiteit Brussel (VUB), 1090 Brussels (Belgium); Takacs, S.; Ditroi, F. [Institute of Nuclear Research of the Hungarian Academy of Sciences (ATOMKI), 4026 Debrecen, Bem ter 18/c (Hungary); Kiraly, B. [Institute of Nuclear Research of the Hungarian Academy of Sciences (ATOMKI), 4026 Debrecen, Bem ter 18/c (Hungary)], E-mail: kiralyb@atomki.hu; Yamazaki, H.; Baba, M.; Mohammadi, A. [Cyclotron and Radioisotope Center (CYRIC), Tohoku University, Sendai 980-8578 (Japan); Ignatyuk, A.V. [Institute of Physics and Power Engineering (IPPE), Obninsk 249020 (Russian Federation)

    2009-09-01

    Cross sections of proton induced nuclear reactions on ytterbium were measured up to 70 MeV by using the standard stacked foil irradiation technique and high-resolution gamma-ray spectroscopy. Experimental cross sections and derived integral yields are reported for the first time for the {sup nat}Yb(p,xn){sup 173,172mg,171mg,170,167}Lu, {sup nat}Yb(p,x){sup 175cum,166cum}Yb and {sup nat}Yb(p,x){sup 173ind,172ind,168,167cum,165cum}Tm reactions. No earlier experimental cross section data were found in the literature. The experimental data were compared to and analyzed with the results of the theoretical model code ALICE-IPPE. Production routes of medical radioisotope {sup 167}Tm are discussed.

  4. Measurement and evaluation of the excitation functions for alpha particle induced nuclear reactions on niobium

    CERN Document Server

    Tarkanyi, F; Szelecsenyi, F; Sonck, M; Hermanne, A

    2002-01-01

    Alpha particle induced nuclear reactions were investigated with the stacked foil activation technique on natural niobium targets up to 43 MeV. Excitation functions were measured for the production of sup 9 sup 6 sup m sup g Tc, sup 9 sup 5 sup m Tc, sup 9 sup 5 sup g Tc, sup 9 sup 4 sup g Tc, sup 9 sup 5 sup m sup g Nb and sup 9 sup 2 sup m Nb. Cumulative cross-sections, thick target yields and activation functions were deduced and compared with available literature data. Applications of the excitation functions in the field of thin layer activation techniques and beam monitoring are also discussed.

  5. Nuclear fragmentation induced by low-energy antiprotons within a microscopic transport approach

    CERN Document Server

    Feng, Zhao-Qing

    2016-01-01

    Within the framework of the Lanzhou quantum molecular dynamics (LQMD) transport model, the nuclear fragmentation induced by low-energy antiprotons has been investigated thoroughly. A coalescence approach is developed for constructing the primary fragments in phase space. The secondary decay process of the fragments is described by the well-known statistical code. It is found that the localized energy released in antibaryon-baryon annihilation is deposited in a nucleus mainly via pion-nucleon collisions, which leads to the emissions of pre-equilibrium particles, fission, evaporation of nucleons and light fragments etc. The strangeness exchange reactions dominate the hyperon production. The averaged mass loss increases with the mass number of target nucleus. A bump structure in the domain of intermediate mass for heavy targets appears owing to the contribution of fission fragments.

  6. Activation cross sections of proton induced nuclear reactions on palladium up to 80 MeV

    CERN Document Server

    Tárkányi, F; Takács, S; Csikai, J; Hermanne, A; Uddin, S; Baba, M

    2016-01-01

    Activation cross sections of proton induced nuclear reactions on palladium were measured up to 80 MeV by using the stacked foil irradiation technique and gamma ray spectrometry. The beam intensity, the incident energy and the energy degradation were controlled by a method based on flux constancy via normalization to the excitation functions of monitor reactions measured in parallel. Excitation functions for direct and cumulative cross-sections were measured for the production of ${}^{104m,104g,105}$${}^{g,106m,110m}$Ag, ${}^{100,101}$Pd, ${}^{99m,99g,100,}$${}^{101m}$${}^{,101g,102m,102g,105}$Rh and ${}^{103,}$${}^{97}$Ru radioisotopes. The cross section data were compared with the theoretical predictions of TENDL-2014 and -2015 libraries. For practical applications thick target yields were derived from the measured excitation functions. Application in the field of medical radionuclide production is shortly discussed.

  7. Nuclear fragmentation and charge-exchange reactions induced by pions in the $\\Delta$-resonance region

    CERN Document Server

    Feng, Zhao-Qing

    2016-01-01

    Dynamics of the nuclear fragmentations and the charge exchange reactions in pion-nucleus collisions near the $\\Delta$(1232) resonance energies has been investigated within the Lanzhou quantum molecular dynamics (LQMD) transport model. An isospin, momentum and density-dependent pion-nucleon potential is implemented in the model, which influences the pion dynamics, in particular the kinetic energy spectra, but weakly impacts the fragmentation mechanism. The absorption process in pion-nucleon collisions to form the $\\Delta$(1232) resonance dominates the heating mechanism of target nucleus. The excitation energy transferred to the target nucleus increases with the pion kinetic energy and is similar for both $\\pi^{-}$ and $\\pi^{+}$ induced reactions. The magnitude of fragmentation of target nucleus weakly depends on the pion energy. The isospin ratio in the pion double charge exchange is influenced by the isospin ingredient of target nucleus.

  8. Nuclear fragmentation induced by low-energy antiprotons within a microscopic transport approach

    Science.gov (United States)

    Feng, Zhao-Qing

    2016-12-01

    Within the framework of the Lanzhou quantum molecular-dynamics transport model, the nuclear fragmentation induced by low-energy antiprotons has been investigated thoroughly. A coalescence approach is developed for constructing the primary fragments in phase space. The secondary decay process of the fragments is described by a well-known statistical code. It is found that the localized energy released in antibaryon-baryon annihilation is deposited in a nucleus mainly via pion-nucleon collisions, which leads to the emissions of pre-equilibrium particles, fission, evaporation of nucleons, light fragments, etc. The strangeness exchange reactions dominate the hyperon production. The averaged mass loss increases with the mass number of target nucleus. A bump structure in the domain of intermediate mass for heavy targets appears owing to the contribution of fission fragments.

  9. Induced adult stem (iAS) cells and induced transit amplifying progenitor (iTAP) cells-a possible alternative to induced pluripotent stem (iPS) cells?

    Science.gov (United States)

    Heng, Boon Chin; Richards, Mark; Ge, Zigang; Shu, Yimin

    2010-02-01

    The successful derivation of iPSC lines effectively demonstrates that it is possible to reset the 'developmental clock' of somatic cells all the way back to the initial embryonic state. Hence, it is plausible that this clock may instead be turned back half-way to a less immature developmental stage that is more directly applicable to clinical therapeutic applications or for in vitro pharmacology/toxicology screening assays. Such a suitable developmental state is postulated to be either the putative transit amplifying progenitor stage or adult stem cell stage. It is hypothetically possible to reprogram mature and terminally differentiated somatic cells back to the adult stem cell or transit amplifying progenitor stage, in a manner similar to the derivation of iPSC. It is proposed that the terminology 'Induced Adult Stem Cells' (iASC) or 'Induced Transit Amplifying Progenitor Cells' (iTAPC) be used to described such reprogrammed somatic cells. Of particular interest, is the possibility of resetting the developmental clock of mature differentiated somatic cells of the mesenchymal lineage, explanted from adipose tissue, bone marrow and cartilage. The putative adult stem cell sub-population from which these cells are derived, commonly referred to as 'mesenchymal stem cells', are highly versatile and hold much therapeutic promise in regenerative medicine, as attested to by numerous human clinical trials and animal studies. Perhaps it may be appropriate to term such reprogrammed cells as 'Induced Mesenchymal Stem Cells' (iMSC) or as 'Induced Mesenchumal Progenitor Cells' (iMPC). Given that cells from the same organ/tissue will share some commonalities in gene expression, we hypothesize that the generation of iASC or iTAPC would be more efficient as compared to iPSC generation, since a common epigenetic program must exist between the reprogrammed cells, adult stem cell or progenitor cell types and terminally differentiated cell types from the same organ/tissue.

  10. Heterogeneous nuclear ribonucleoprotein K inhibits heat shock-induced transcriptional activity of heat shock factor 1.

    Science.gov (United States)

    Kim, Hee-Jung; Lee, Jae-Jin; Cho, Jin-Hwan; Jeong, Jaeho; Park, A Young; Kang, Wonmo; Lee, Kong-Joo

    2017-08-04

    When cells are exposed to heat shock and various other stresses, heat shock factor 1 (HSF1) is activated, and the heat shock response (HSR) is elicited. To better understand the molecular regulation of the HSR, we used 2D-PAGE-based proteome analysis to screen for heat shock-induced post-translationally modified cellular proteins. Our analysis revealed that two protein spots typically present on 2D-PAGE gels and containing heterogeneous nuclear ribonucleoprotein K (hnRNP K) with trioxidized Cys(132) disappeared after the heat shock treatment and reappeared during recovery, but the total amount of hnRNP K protein remained unchanged. We next tested whether hnRNP K plays a role in HSR by regulating HSF1 and found that hnRNP K inhibits HSF1 activity, resulting in reduced expression of hsp70 and hsp27 mRNAs. hnRNP K also reduced binding affinity of HSF1 to the heat shock element by directly interacting with HSF1 but did not affect HSF1 phosphorylation-dependent activation or nuclear localization. hnRNP K lost its ability to induce these effects when its Cys(132) was substituted with Ser, Asp, or Glu. These findings suggest that hnRNP K inhibits transcriptional activity of HSF1 by inhibiting its binding to heat shock element and that the oxidation status of Cys(132) in hnRNP K is critical for this inhibition. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  11. Simvastatin Attenuates TGF-β1-Induced Epithelial-Mesenchymal Transition in Human Alveolar Epithelial Cells

    Directory of Open Access Journals (Sweden)

    Tuo Yang

    2013-06-01

    Full Text Available Background: Transforming growth factor-β1 (TGF-β1-induced epithelial-mesenchymal transition (EMT of alveolar epithelial cells (AEC may contribute to idiopathic pulmonary fibrosis (IPF. TGF-β1-induced EMT in A549 cells (a human AEC cell line resulted in the adoption of mesenchymal responses that were predominantly mediated via the TGF-β1-Smad2/3 signaling pathway. Simvastatin (Sim, a 3-hydroxy-3-methylglutaryl CoA (HMG-CoA reductase inhibitor, has been previously reported to inhibit EMT in human proximal tubular epithelial cells and porcine lens epithelial cells and to suppress Smad2/3 phosphorylation in animal models. However, whether Sim can attenuate TGF-β1-induced EMT in A549 cells and its underlying mechanisms remains unknown. Methods: Cells were incubated with TGF-β1 in the presence or absence of Sim. The epithelial marker E-cadherin (E-Cad and the mesenchymal markers, α-smooth muscle actin (α-SMA, vimentin (Vi and fibronectin (FN, were detected using western blotting analyses and immunofluorescence. Phosphorylated Smad2 and Smad3 levels and connective tissue growth factor (CTGF were analyzed using western blotting. In addition, a cell migration assay was performed. Moreover, the levels of matrix metalloproteinase (MMP-2 and -9 in the culture medium were examined using ELISA. Results: Sim significantly attenuated the TGF-β1-induced decrease in E-Cad levels and elevated the levels of α-SMA, Vi and FN via the suppression of Smad2 and Smad3 phosphorylation. Furthermore, Sim inhibited the mesenchymal-like responses in A549 cells, including cell migration, CTGF expression and secretion of MMP-2 and -9. However, Sim failed to reverse the cell morphologial changes induced by TGF-β1 in A549 cells. Conclusion: Sim attenuated TGF-β1-induced EMT in A549 cells and might be a promising therapeutic agent for treating IPF.

  12. 2-Methylcitric acid impairs glutamate metabolism and induces permeability transition in brain mitochondria.

    Science.gov (United States)

    Amaral, Alexandre Umpierrez; Cecatto, Cristiane; Castilho, Roger Frigério; Wajner, Moacir

    2016-04-01

    Accumulation of 2-methylcitric acid (2MCA) is observed in methylmalonic and propionic acidemias, which are clinically characterized by severe neurological symptoms. The exact pathogenetic mechanisms of brain abnormalities in these diseases are poorly established and very little has been reported on the role of 2MCA. In the present work we found that 2MCA markedly inhibited ADP-stimulated and uncoupled respiration in mitochondria supported by glutamate, with a less significant inhibition in pyruvate plus malate respiring mitochondria. However, no alterations occurred when α-ketoglutarate or succinate was used as respiratory substrates, suggesting a defect on glutamate oxidative metabolism. It was also observed that 2MCA decreased ATP formation in glutamate plus malate or pyruvate plus malate-supported mitochondria. Furthermore, 2MCA inhibited glutamate dehydrogenase activity at concentrations as low as 0.5 mM. Kinetic studies revealed that this inhibitory effect was competitive in relation to glutamate. In contrast, assays of osmotic swelling in non-respiring mitochondria suggested that 2MCA did not significantly impair mitochondrial glutamate transport. Finally, 2MCA provoked a significant decrease in mitochondrial membrane potential and induced swelling in Ca(2+)-loaded mitochondria supported by different substrates. These effects were totally prevented by cyclosporine A plus ADP or ruthenium red, indicating induction of mitochondrial permeability transition. Taken together, our data strongly indicate that 2MCA behaves as a potent inhibitor of glutamate oxidation by inhibiting glutamate dehydrogenase activity and as a permeability transition inducer, disturbing mitochondrial energy homeostasis. We presume that 2MCA-induced mitochondrial deleterious effects may contribute to the pathogenesis of brain damage in patients affected by methylmalonic and propionic acidemias. We propose that brain glutamate oxidation is disturbed by 2-methylcitric acid (2MCA), which

  13. Epithelial-mesenchymal transition (EMT) induced by TNF-α requires AKT/GSK-3β-mediated stabilization of snail in colorectal cancer.

    Science.gov (United States)

    Wang, Hao; Wang, Hong-Sheng; Zhou, Bin-Hua; Li, Cui-Lin; Zhang, Fan; Wang, Xian-Feng; Zhang, Ge; Bu, Xian-Zhang; Cai, Shao-Hui; Du, Jun

    2013-01-01

    Chronic inflammation-promoted metastasis has been considered as a major challenge in cancer therapy. Pro-inflammatory cytokine TNFα can induce cancer invasion and metastasis associated with epithelial-mesenchymal transition (EMT). However, the underlying mechanisms are not entirely clear. In this study, we showed that TNFα induces EMT in human HCT116 cells and thereby promotes colorectal cancer (CRC) invasion and metastasis. TNFα-induced EMT was characterized by acquiring mesenchymal spindle-like morphology and increasing the expression of N-cadherin and fibronectin with a concomitant decrease of E-cadherin and Zona occludin-1(ZO-1). TNFα treatment also increased the expression of transcription factor Snail, but not Slug, ZEB1 and Twist. Overexpression of Snail induced a switch from E-cadherin to N-cadherin expression in HCT116 cells, which is a characteristic of EMT. Conversely, knockdown of Snail significantly attenuated TNFα-induced EMT in HCT116 cells, suggesting that Snail plays a crucial role in TNFα-induced EMT. Interestingly, exposure to TNFα rapidly increased Snail protein expression and Snail nuclear localization but not mRNA level upregulation. Finally, we demonstrated that TNFα elevated Snail stability by activating AKT pathway and subsequently repressing GSK-3β activity and decreasing the association of Snail with GSK-3β. Knockdown of GSK-3β further verified our finding. Taken together, these results revealed that AKT/GSK-3β-mediated stabilization of Snail is required for TNFα-induced EMT in CRC cells. Our study provides a better understanding of inflammation-induced CRC metastasis.

  14. Epithelial–Mesenchymal Transition (EMT) Induced by TNF-α Requires AKT/GSK-3β-Mediated Stabilization of Snail in Colorectal Cancer

    Science.gov (United States)

    Wang, Hao; Wang, Hong-Sheng; Zhou, Bin-Hua; Li, Cui-Lin; Zhang, Fan; Wang, Xian-Feng; Zhang, Ge; Bu, Xian-Zhang; Cai, Shao-Hui; Du, Jun

    2013-01-01

    Chronic inflammation-promoted metastasis has been considered as a major challenge in cancer therapy. Pro-inflammatory cytokine TNFα can induce cancer invasion and metastasis associated with epithelial–mesenchymal transition (EMT). However, the underlying mechanisms are not entirely clear. In this study, we showed that TNFα induces EMT in human HCT116 cells and thereby promotes colorectal cancer (CRC) invasion and metastasis. TNFα-induced EMT was characterized by acquiring mesenchymal spindle-like morphology and increasing the expression of N-cadherin and fibronectin with a concomitant decrease of E-cadherin and Zona occludin-1(ZO-1). TNFα treatment also increased the expression of transcription factor Snail, but not Slug, ZEB1 and Twist. Overexpression of Snail induced a switch from E-cadherin to N-cadherin expression in HCT116 cells, which is a characteristic of EMT. Conversely, knockdown of Snail significantly attenuated TNFα-induced EMT in HCT116 cells, suggesting that Snail plays a crucial role in TNFα-induced EMT. Interestingly, exposure to TNFα rapidly increased Snail protein expression and Snail nuclear localization but not mRNA level upregulation. Finally, we demonstrated that TNFα elevated Snail stability by activating AKT pathway and subsequently repressing GSK-3β activity and decreasing the association of Snail with GSK-3β. Knockdown of GSK-3β further verified our finding. Taken together, these results revealed that AKT/GSK-3β-mediated stabilization of Snail is required for TNFα-induced EMT in CRC cells. Our study provides a better understanding of inflammation-induced CRC metastasis. PMID:23431386

  15. Ribosomal Protein S6 Kinase (RSK-2 as a central effector molecule in RON receptor tyrosine kinase mediated epithelial to mesenchymal transition induced by macrophage-stimulating protein

    Directory of Open Access Journals (Sweden)

    Zhang Rui-Wen

    2011-05-01

    Full Text Available Abstract Background Epithelial to mesenchymal transition (EMT occurs during cancer cell invasion and malignant metastasis. Features of EMT include spindle-like cell morphology, loss of epithelial cellular markers and gain of mesenchymal phenotype. Activation of the RON receptor tyrosine kinase by macrophage-stimulating protein (MSP has been implicated in cellular EMT program; however, the major signaling determinant(s responsible for MSP-induced EMT is unknown. Results The study presented here demonstrates that RSK2, a downstream signaling protein of the Ras-Erk1/2 pathway, is the principal molecule that links MSP-activated RON signaling to complete EMT. Using MDCK cells expressing RON as a model, a spindle-shape based screen was conducted, which identifies RSK2 among various intracellular proteins as a potential signaling molecule responsible for MSP-induced EMT. MSP stimulation dissociated RSK2 with Erk1/2 and promoted RSK2 nuclear translocation. MSP strongly induced RSK2 phosphorylation in a dose-dependent manner. These effects relied on RON and Erk1/2 phosphorylation, which is significantly potentiated by transforming growth factor (TGF-β1, an EMT-inducing cytokine. Specific RSK inhibitor SL0101 completely prevented MSP-induced RSK phosphorylation, which results in inhibition of MSP-induced spindle-like morphology and suppression of cell migration associated with EMT. In HT-29 cancer cells that barely express RSK2, forced RSK2 expression results in EMT-like phenotype upon MSP stimulation. Moreover, specific siRNA-mediated silencing of RSK2 but not RSK1 in L3.6pl pancreatic cancer cells significantly inhibited MSP-induced EMT-like phenotype and cell migration. Conclusions MSP-induced RSK2 activation is a critical determinant linking RON signaling to cellular EMT program. Inhibition of RSK2 activity may provide a therapeutic opportunity for blocking RON-mediated cancer cell migration and subsequent invasion.

  16. Nuclear magnetic resonance-based metabolomics for prediction of gastric damage induced by indomethacin in rats

    Energy Technology Data Exchange (ETDEWEB)

    Um, So Young [Department of Pharmacology, National Institute of Toxicological Research, Korea Food and Drug Administration, 643 Yeonje-ri, Gangoe-myeon, Cheongwon-gun, Chungbuk (Korea, Republic of); Division of Life and Pharmaceutical Science and College of Pharmacy, Ewha Womans University, 52 Ewahyeodae-gil, Seodaemun-gu, Seoul (Korea, Republic of); Park, Jung Hyun [Division of Life and Pharmaceutical Science and College of Pharmacy, Ewha Womans University, 52 Ewahyeodae-gil, Seodaemun-gu, Seoul (Korea, Republic of); Chung, Myeon Woo [Department of Pharmacology, National Institute of Toxicological Research, Korea Food and Drug Administration, 643 Yeonje-ri, Gangoe-myeon, Cheongwon-gun, Chungbuk (Korea, Republic of); Kim, Kyu-Bong [College of Pharmacy, Dankook University, Dandae-ro, Cheonan, Chungnam (Korea, Republic of); Kim, Seon Hwa [Department of Pharmacology, National Institute of Toxicological Research, Korea Food and Drug Administration, 643 Yeonje-ri, Gangoe-myeon, Cheongwon-gun, Chungbuk (Korea, Republic of); Division of Life and Pharmaceutical Science and College of Pharmacy, Ewha Womans University, 52 Ewahyeodae-gil, Seodaemun-gu, Seoul (Korea, Republic of); College of Pharmacy, Dankook University, Dandae-ro, Cheonan, Chungnam (Korea, Republic of); Choi, Ki Hwan, E-mail: hyokwa11@korea.kr [Department of Pharmacology, National Institute of Toxicological Research, Korea Food and Drug Administration, 643 Yeonje-ri, Gangoe-myeon, Cheongwon-gun, Chungbuk (Korea, Republic of); Lee, Hwa Jeong, E-mail: hwalee@ewha.ac.kr [Division of Life and Pharmaceutical Science and College of Pharmacy, Ewha Womans University, 52 Ewahyeodae-gil, Seodaemun-gu, Seoul (Korea, Republic of)

    2012-04-13

    Highlights: Black-Right-Pointing-Pointer NMR based metabolomics - gastric damage by indomethacin. Black-Right-Pointing-Pointer Pattern recognition analysis was performed to biomarkers of gastric damage. Black-Right-Pointing-Pointer 2-Oxoglutarate, acetate, taurine and hippurate were selected as putative biomarkers. Black-Right-Pointing-Pointer The gastric damage induced by NSAIDs can be screened in the preclinical step of drug. - Abstract: Non-steroidal anti-inflammatory drugs (NSAIDs) have side effects including gastric erosions, ulceration and bleeding. In this study, pattern recognition analysis of the {sup 1}H-nuclear magnetic resonance (NMR) spectra of urine was performed to develop surrogate biomarkers related to the gastrointestinal (GI) damage induced by indomethacin in rats. Urine was collected for 5 h after oral administration of indomethacin (25 mg kg{sup -1}) or co-administration with cimetidine (100 mg kg{sup -1}), which protects against GI damage. The {sup 1}H-NMR urine spectra were divided into spectral bins (0.04 ppm) for global profiling, and 36 endogenous metabolites were assigned for targeted profiling. The level of gastric damage in each animal was also determined. Indomethacin caused severe gastric damage; however, indomethacin administered with cimetidine did not. Simultaneously, the patterns of changes in their endogenous metabolites were different. Multivariate data analyses were carried out to recognize the spectral pattern of endogenous metabolites related to indomethacin using partial least square-discrimination analysis. In targeted profiling, a few endogenous metabolites, 2-oxoglutarate, acetate, taurine and hippurate, were selected as putative biomarkers for the gastric damage induced by indomethacin. These metabolites changed depending on the degree of GI damage, although the same dose of indomethacin (10 mg kg{sup -1}) was administered to rats. The results of global and targeted profiling suggest that the gastric damage induced by

  17. Evaluation of p53 nuclear accumulation in low- and high-grade (WHO/ISUP classification) transitional papillary carcinomas of the bladder for tumor recurrence and progression.

    Science.gov (United States)

    Vardar, Enver; Gunlusoy, Bulent; Minareci, Süleyman; Postaci, Hakan; Ayder, Ali Riza

    2006-01-01

    To evaluate the association of p53 nuclear accumulation with recurrence and progression in transitional cell carcinomas of the bladder and to examine the distribution of p53 in low-grade and high-grade transitional cell carcinomas according to the World Health Organization/International Society of Urological Pathology classification. Nuclear accumulations of p53 were examined in a total of 99 patients with transitional cell carcinoma between May 1995 and October 1999. The mean age was 64 years. There were 94 (95%) men and 5 (5%) women. Following resection, surgical specimens were examined, and p53 accumulation with a 20% cutoff value was accepted as positive staining. Of the 99 patients, 52 (53%) had histologically superficial bladder tumors, and 47 (47%) had invasive tumors. Data concerning grade, stage, number of recurrences, and disease progression were available for each patient. The median follow-up period was 55 months. 60 of the 99 patients (61%) had p53 overexpression. The difference for p53 overexpression between low-grade and high-grade tumors was significant (p 0.05), but its relationship with progression was statistically significant (p < 0.05). We did not find a correlation between tumor recurrence and p53 overexpression, but p53 overexpression has a predictive value in determining tumor progression. High-grade tumors had higher p53-positive values than low-grade tumors. This group of patients should be considered for radical therapies on the basis of other prognostic parameters.

  18. Engineering light-inducible nuclear localization signals for precise spatiotemporal control of protein dynamics in living cells.

    Science.gov (United States)

    Niopek, Dominik; Benzinger, Dirk; Roensch, Julia; Draebing, Thomas; Wehler, Pierre; Eils, Roland; Di Ventura, Barbara

    2014-07-14

    The function of many eukaryotic proteins is regulated by highly dynamic changes in their nucleocytoplasmic distribution. The ability to precisely and reversibly control nuclear translocation would, therefore, allow dissecting and engineering cellular networks. Here we develop a genetically encoded, light-inducible nuclear localization signal (LINuS) based on the LOV2 domain of Avena sativa phototropin 1. LINuS is a small, versatile tag, customizable for different proteins and cell types. LINuS-mediated nuclear import is fast and reversible, and can be tuned at different levels, for instance, by introducing mutations that alter AsLOV2 domain photo-caging properties or by selecting nuclear localization signals (NLSs) of various strengths. We demonstrate the utility of LINuS in mammalian cells by controlling gene expression and entry into mitosis with blue light.

  19. Regulation of the Drosophila Hypoxia-Inducible Factor α Sima by CRM1-Dependent Nuclear Export ▿

    Science.gov (United States)

    Romero, Nuria M.; Irisarri, Maximiliano; Roth, Peggy; Cauerhff, Ana; Samakovlis, Christos; Wappner, Pablo

    2008-01-01

    Hypoxia-inducible factor α (HIF-α) proteins are regulated by oxygen levels through several different mechanisms that include protein stability, transcriptional coactivator recruitment, and subcellular localization. It was previously reported that these transcription factors are mainly nuclear in hypoxia and cytoplasmic in normoxia, but so far the molecular basis of this regulation is unclear. We show here that the Drosophila melanogaster HIF-α protein Sima shuttles continuously between the nucleus and the cytoplasm. We identified the relevant nuclear localization signal and two functional nuclear export signals (NESs). These NESs are in the Sima basic helix-loop-helix (bHLH) domain and promote CRM1-dependent nuclear export. Site-directed mutagenesis of either NES provoked Sima nuclear retention and increased transcriptional activity, suggesting that nuclear export contributes to Sima regulation. The identified NESs are conserved and probably functional in the bHLH domains of several bHLH-PAS proteins. We propose that rapid nuclear export of Sima regulates the duration of cellular responses to hypoxia. PMID:18332128

  20. Pressure-induced phase transitions in acentric BaHf(BO{sub 3}){sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Mączka, Mirosław, E-mail: m.maczka@int.pan.wroc.pl [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, P.O. Box 1410, 50-950 Wrocław 2 (Poland); Szymborska-Małek, Katarzyna [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, P.O. Box 1410, 50-950 Wrocław 2 (Poland); Sousa Pinheiro, Gardenia de [Departamento de Física, Universidade Federal do Piauí, Teresina, PI 64049-550 (Brazil); Cavalcante Freire, Paulo Tarso [Departamento de Fisica, Universidade Federal do Ceara, Fortaleza CE-60455-970 (Brazil); Majchrowski, Andrzej [Institute of Applied Physics, Military University of Technology, 2 Kaliskiego Street, 00-908 Warszawa (Poland)

    2015-08-15

    High-pressure Raman scattering studies revealed that BaHf(BO{sub 3}){sub 2} is more compressible than calcite-type orthoborates and calcite, aragonite or dolomite carbonates. It undergoes a first-order reversible pressure-induced phase transition in the 3.9–4.4 GPa pressure range. Second structural change is observed at 9.2 GPa. The intermediate phase is most likely trigonal. However, Raman results suggest increase in the number of distinct BO{sub 3} groups from two in the ambient pressure phase to at least three in the intermediate phase. This intermediate phase is also strongly compressible and strong pressure dependence of the lattice modes proves that the main changes under pressure occur within the layers built from BaO{sub 6} and HfO{sub 6} octahedra. The second phase transition leads most likely to lowering of the trigonal symmetry, as evidenced by significant increase of the number of observed bands. The pressure coefficients of the Raman bands of the high-pressure phase are relatively small, suggesting more dense arrangement of the metal–oxygen polyhedra and BO{sub 3} groups in this phase. It is worth noting that the high-pressure phase was not reached in the second compression experiment up to 10 GPa. This behavior can be most likely attributed to worse hydrostatic conditions of the first experiment. - Graphical abstract: Raman spectra of BaHf(BO{sub 3}){sub 2} recorded at different pressures during compression showing onset of pressure-induced phase transitions. - Highlights: • High-pressure Raman spectra were measured for BaHf(BO{sub 3}){sub 2.} • BaHf(BO{sub 3}){sub 2} undergoes a reversible first-order phase transition at 3.9–4.4 GPa into a trigonal phase. • The intermediate trigonal phase is strongly compressible second structural transformation is observed at 9.2 GPa under non-perfect hydrostatic conditions.

  1. Refinement of the gross theory of nuclear {beta}-decay, and hindrance of the first-forbidden transition of rank 1

    Energy Technology Data Exchange (ETDEWEB)

    Nakata, Hidehiko [Waseda Univ., Tokyo (Japan). Dept. of Physics; Tachibana, Takahiro; Yamada, Masami

    1997-03-01

    Recently the gross theory of nuclear {beta}-decay was refined for odd-odd nuclei. In this refinement, the effect of the selection rule of {beta}-transitions from the ground states of odd-odd nuclei to those of even-even nuclei was taken into account based on a statistical consideration. The transitions to the first 2{sup +} excited states in even-even nuclei were also taken into account according to the selection rule approximately. In that study, it was found that the transitions between 1{sup -} ground states of the odd-odd nuclei and 0{sup +} ground states of even-even nuclei, belonging to the first-forbidden transitions of rank 1, are strongly hindered. A reduction factor was introduced for the transitions to the ground states of even-even nuclei to take into account this hindrance. It was also found that the strength functions of the Gamow-Teller transitions obtained from the conventional gross theory are underestimated by a factor of about 3. In order to improve this underestimation, the Lorentz-type function was adopted for the one-particle strength function in the model instead of the hyperbolic-secant-type function. In the present study we have newly analyzed the experimental ft-values of odd-A nuclei, and found that the first-forbidden transitions of rank 1 are also considerably hindered between the ground states. Following the above refinement we have calculated the {beta}-ray spectra of some odd-odd short-lived fission products with the use of the refined gross theory. These results are compared not only with the experiments by Rudstam et al. but also with the conventional gross theory. (author)

  2. Chidamide alleviates TGF-β-induced epithelial-mesenchymal transition in lung cancer cell lines.

    Science.gov (United States)

    Lin, Sheng-Hao; Wang, Bing-Yen; Lin, Ching-Hsiung; Chien, Peng-Ju; Wu, Yueh-Feng; Ko, Jiunn-Liang; Chen, Jeremy J W

    2016-07-01

    Transforming growth factor-β (TGF-β)-induced epithelial-mesenchymal transition is a critical process in the initiation of metastasis of various types of cancer. Chidamide is a class I histone deacetylase inhibitor with anti-tumor activity. This study investigated the effects of chidamide on TGF-β-mediated suppression of E-cadherin expression in adenocarcinomic lung epithelial cells and the molecular mechanisms involved in these effects. Western blot analysis, confocal microscopy, Quantitative methyl-specific PCR and bisulfite sequencing were used to evaluate the effects of different treatments on chidamide ameliorating TGF-β induced-E-cadherin loss. H3 acetylation binding to the promoter of E-cadherin was detected by chromatin immunoprecipitations (CHIP). We found that chidamide reduced the level of lung cancer cell migration observed using a Boyden chamber assay (as an indicator of metastatic potential). Chidamide inhibited TGF-β-induced SMAD2 phosphorylation and attenuated TGF-β-induced loss of E-cadherin expression in lung cancer cells by Western blotting and confocal microscopy, respectively. Quantitative methyl-specific PCR and bisulfite sequencing revealed that TGF-β-enhanced E-cadherin promoter methylation was ameliorated in cells treated with chidamide. We demonstrated that histone H3 deacetylation within the E-cadherin promoter was required for TGF-β-induced E-cadherin loss; cell treatment with chidamide increased the H3 acetylation detected by CHIP. Taken together, our results demonstrate that TGF-β suppressed E-cadherin expression by regulating promoter methylation and histone H3 acetylation. Chidamide significantly enhanced E-cadherin expression in TGF-β-treated cells and inhibited lung cancer cell migration. These findings indicate that chidamide has a potential therapeutic use due to its capacity to prevent cancer cell metastasis.

  3. Negative regulation of TGFβ-induced lens epithelial to mesenchymal transition (EMT) by RTK antagonists.

    Science.gov (United States)

    Zhao, Guannan; Wojciechowski, Magdalena C; Jee, Seonah; Boros, Jessica; McAvoy, John W; Lovicu, Frank J

    2015-03-01

    An eclectic range of ocular growth factors with differing actions are present within the aqueous and vitreous humors that bathe the lens. Growth factors that exert their actions via receptor tyrosine kinases (RTKs), such as FGF, play a normal regulatory role in lens; whereas other factors, such as TGFβ, can lead to an epithelial to mesenchymal transition (EMT) that underlies several forms of cataract. The respective downstream intracellular signaling pathways of these factors are in turn tightly regulated. One level of negative regulation is thought to be through RTK-antagonists, namely, Sprouty (Spry), Sef and Spred that are all expressed in the lens. In this study, we tested these different negative regulators and compared their ability to block TGFβ-induced EMT in rat lens epithelial cells. Spred expression within the rodent eye was confirmed using RT-PCR, western blotting and immunofluorescence. Rat lens epithelial explants were used to examine the morphological changes associated with TGFβ-induced EMT over 3 days of culture, as well as α-smooth muscle actin (α-sma) immunolabeling. Cells in lens epithelial explants were transfected with either a reporter (EGFP) vector (pLXSG), or with plasmids also coding for different RTK-antagonists (i.e. pLSXG-Spry1, pLSXG-Spry2, pLXSG-Sef, pLSXG-Spred1, pLSXG-Spred2, pLSXG-Spred3), before treating with TGFβ for up to 3 days. The percentages of transfected cells that underwent TGFβ-induced morphological changes consistent with an EMT were determined using cell counts and validated with a paired two-tailed t-test. Explants transfected with pLXSG demonstrated a distinct transition in cell morphology after TGFβ treatment, with ∼60% of the cells undergoing fibrotic-like cell elongation. This percentage was significantly reduced in cells overexpressing the different antagonists, indicative of a block in lens EMT. Of the antagonists tested under these in vitro conditions, Spred1 was the most potent demonstrating the

  4. Modeling Hydrogen-Induced Cracking of Titanium Alloys in Nuclear Waste Repository Environments

    Energy Technology Data Exchange (ETDEWEB)

    F. Hua; K. Mon; P. Pasupathi; G. Gordon

    2004-09-08

    This paper reviews the current understanding of hydrogen-induced cracking (HIC) of Ti Grade 7 and other relevant titanium alloys within the context of the current waste package design for the repository environmental conditions anticipated within the Yucca Mountain repository. The review concentrates on corrosion processes possible in the aqueous environments expected within this site. A brief background discussion of the relevant properties of titanium alloys, the hydrogen absorption process, and the properties of passive film on titanium alloys is presented as the basis for the subsequent discussion of model developments. The key corrosion processes that could occur are addressed individually. Subsequently, the expected corrosion performance of these alloys under the specific environmental conditions anticipated at Yucca Mountain is considered. It can be concluded that, based on the conservative modeling approaches adopted, hydrogen-induced cracking of titanium alloys will not occur under nuclear waste repository conditions since there will not be sufficient hydrogen in the alloy after 10,000 years of emplacement.

  5. First measurement of proton-induced low-momentum dielectron radiation off cold nuclear matter

    Science.gov (United States)

    HADES Collaboration; Agakishiev, G.; Balanda, A.; Belver, D.; Belyaev, A.; Berger-Chen, J. C.; Blanco, A.; Böhmer, M.; Boyard, J. L.; Cabanelas, P.; Chernenko, S.; Dybczak, A.; Epple, E.; Fabbietti, L.; Fateev, O.; Finocchiaro, P.; Fonte, P.; Friese, J.; Fröhlich, I.; Galatyuk, T.; Garzón, J. A.; Gernhäuser, R.; Göbel, K.; Golubeva, M.; González-Díaz, D.; Guber, F.; Gumberidze, M.; Heinz, T.; Hennino, T.; Holzmann, R.; Ierusalimov, A.; Iori, I.; Ivashkin, A.; Jurkovic, M.; Kämpfer, B.; Karavicheva, T.; Koenig, I.; Koenig, W.; Kolb, B. W.; Kornakov, G.; Kotte, R.; Krása, A.; Krizek, F.; Krücken, R.; Kuc, H.; Kühn, W.; Kugler, A.; Kurepin, A.; Ladygin, V.; Lalik, R.; Lang, S.; Lapidus, K.; Lebedev, A.; Liu, T.; Lopes, L.; Lorenz, M.; Maier, L.; Mangiarotti, A.; Markert, J.; Metag, V.; Michalska, B.; Michel, J.; Mishra, D.; Müntz, C.; Naumann, L.; Pachmayer, Y. C.; Palka, M.; Parpottas, Y.; Pechenov, V.; Pechenova, O.; Pietraszko, J.; Przygoda, W.; Ramstein, B.; Reshetin, A.; Rustamov, A.; Sadovsky, A.; Salabura, P.; Schmah, A.; Schwab, E.; Siebenson, J.; Sobolev, Yu. G.; Spataro, S.; Spruck, B.; Ströbele, H.; Stroth, J.; Sturm, C.; Tarantola, A.; Teilab, K.; Tlusty, P.; Traxler, M.; Trebacz, R.; Tsertos, H.; Vasiliev, T.; Wagner, V.; Weber, M.; Wendisch, C.; Wüstenfeld, J.; Yurevich, S.; Zanevsky, Y.

    2012-09-01

    We present data on dielectron emission in proton induced reactions on a Nb target at 3.5 GeV kinetic beam energy measured with HADES installed at GSI. The data represent the first high statistics measurement of proton-induced dielectron radiation from cold nuclear matter in a kinematic regime, where strong medium effects are expected. Combined with the good mass resolution of 2%, it is the first measurement sensitive to changes of the spectral functions of vector mesons, as predicted by models for hadrons at rest or small relative momenta. Comparing the e+e- invariant mass spectra to elementary p + p data, we observe for e+e- momenta Pee<0.8 GeV/c a strong modification of the shape of the spectrum, which we attribute to an additional ρ-like contribution and a decrease of ω yield. These opposite trends are tentatively interpreted as a strong coupling of the ρ meson to baryonic resonances and an absorption of the ω meson, which are two aspects of in-medium modification of vector mesons.

  6. Change and significance of nuclear factor-κB in adriamycin induced cardiomyopathy in rats

    Institute of Scientific and Technical Information of China (English)

    LI Hong-li; LIU Bin; ZHOU Ling-wang; YU Wei-han

    2005-01-01

    Background This study aimed at investigating the change and significance of nuclear factor-κB (NF-κB) in cardiomyopathy induced by adriamycin (ADR) in rats.Methods Sixty male Wistar rats were randomly divided into three groups: control, ADR and ADR+pyrrolidine dithiocarbamate (PDTC) groups. After 30-day experiment, myocardial histopathological observation was performed. Location and distribution of NF-κB p50 was examined by immunohistochemical assay. Expression of NF-κB p50 protein was examined by immunobolt assay. Electrophoretic Mobility Shift Assay examined activity of NF-κB; Myocardium p53 gene expression was examined by RT-PCR analysis. Results The myocardial lesions of rats were less pronounced in ADR +PDTC group than in ADR group. Compared with control group, there were many myocardium nucleuses, which expressed NF-κB p50 and distribute under epicardium. Expression of NF-κB p50 protein in nucleus increased significantly in ADR group. The NF-κB binding activity increased significantly in ADR group. Myocardium expressions of p53 mRNA increased in ADR group. Conclusions The NF-κB binding activity increased significantly in cardiomyopathy induced by ADR in rats. Moreover, NF-κB plays an important role in causing degeneration of myocardial tissue and regulating expression of related-apoptosis genes.

  7. Altered nuclear factor-kappaB inducing kinase expression in insulin-resistant mice

    Institute of Scientific and Technical Information of China (English)

    SU Lei; XIU Ling-ling; WEI Guo-hong; ZHONG Xing; LIU Yuan-yuan; CAO Xiao-pei; LI Yan-bing; XIAO Hai-peng

    2011-01-01

    Background Insulin resistance is an underlying feature of both type 2 diabetes and metabolic syndrome.Currently,it is unclear whether nuclear factor (NF)-κB inducing kinase (NIK) plays a role in the development of insulin resistance.The present in vivo study investigated the roles of NIK and IKB kinase α (IKKα) in obesity-induced insulin resistance using animal models.Methods NIK expression was evaluated by Westem blotting in male Lepob mice and C57BL/6J mice fed a high-fat diet (HFD) (45% fat).After metformin and sulfasalazine treatment,NIK expression was investigated during the improvement of insulin resistance.Results NIK was increased by about 1-fold in the renal tissues of Lepob mice and C57BL/6J mice fed a HFD for 12 weeks.After 1 and 3 weeks of high-fat feeding,we observed an almost 50% decrease in NIK and IKKα expression in the liver and renal tissues of C57BL/6J mice.NIK expression was significantly lower in the liver and renal tissues of HFD-fed mice that were treated with insulin sensitizers,metformin and sulfasalazine.However,IKKα expression was increased after metformin treatment in both tissues.Conclusion These results suggest a possible role of NIK in the liver and renal tissues of insulin-resistant mice.

  8. Targeting proliferating cell nuclear antigen and its protein interactions induces apoptosis in multiple myeloma cells.

    Directory of Open Access Journals (Sweden)

    Rebekka Müller

    Full Text Available Multiple myeloma is a hematological cancer that is considered incurable despite advances in treatment strategy during the last decade. Therapies targeting single pathways are unlikely to succeed due to the heterogeneous nature of the malignancy. Proliferating cell nuclear antigen (PCNA is a multifunctional protein essential for DNA replication and repair that is often overexpressed in cancer cells. Many proteins involved in the cellular stress response interact with PCNA through the five amino acid sequence AlkB homologue 2 PCNA-interacting motif (APIM. Thus inhibiting PCNA's protein interactions may be a good strategy to target multiple pathways simultaneously. We initially found that overexpression of peptides containing the APIM sequence increases the sensitivity of cancer cells to contemporary therapeutics. Here we have designed a cell-penetrating APIM-containing peptide, ATX-101, that targets PCNA and show that it has anti-myeloma activity. We found that ATX-101 induced apoptosis in multiple myeloma cell lines and primary cancer cells, while bone marrow stromal cells and primary healthy lymphocytes were much less sensitive. ATX-101-induced apoptosis was caspase-dependent and cell cycle phase-independent. ATX-101 also increased multiple myeloma cells' sensitivity against melphalan, a DNA damaging agent commonly used for treatment of multiple myeloma. In a xenograft mouse model, ATX-101 was well tolerated and increased the anti-tumor activity of melphalan. Therefore, targeting PCNA by ATX-101 may be a novel strategy in multiple myeloma treatment.

  9. Nuclear ARRB1 induces pseudohypoxia and cellular metabolism reprogramming in prostate cancer

    Science.gov (United States)

    Zecchini, Vincent; Madhu, Basetti; Russell, Roslin; Pértega-Gomes, Nelma; Warren, Anne; Gaude, Edoardo; Borlido, Joana; Stark, Rory; Ireland-Zecchini, Heather; Rao, Roheet; Scott, Helen; Boren, Joan; Massie, Charlie; Asim, Mohammad; Brindle, Kevin; Griffiths, John; Frezza, Christian; Neal, David E; Mills, Ian G

    2014-01-01

    Tumour cells sustain their high proliferation rate through metabolic reprogramming, whereby cellular metabolism shifts from oxidative phosphorylation to aerobic glycolysis, even under normal oxygen levels. Hypoxia-inducible factor 1A (HIF1A) is a major regulator of this process, but its activation under normoxic conditions, termed pseudohypoxia, is not well documented. Here, using an integrative approach combining the first genome-wide mapping of chromatin binding for an endocytic adaptor, ARRB1, both in vitro and in vivo with gene expression profiling, we demonstrate that nuclear ARRB1 contributes to this metabolic shift in prostate cancer cells via regulation of HIF1A transcriptional activity under normoxic conditions through regulation of succinate dehydrogenase A (SDHA) and fumarate hydratase (FH) expression. ARRB1-induced pseudohypoxia may facilitate adaptation of cancer cells to growth in the harsh conditions that are frequently encountered within solid tumours. Our study is the first example of an endocytic adaptor protein regulating metabolic pathways. It implicates ARRB1 as a potential tumour promoter in prostate cancer and highlights the importance of metabolic alterations in prostate cancer. PMID:24837709

  10. 1H-NMR and photochemically-induced dynamic nuclear polarization studies on bovine pancreatic phospholipase A2

    NARCIS (Netherlands)

    Egmond, M.R.; Slotboom, A.J.; Haas, G.H. de; Dijkstra, Klaas; Kaptein, R.

    1980-01-01

    Proton-NMR resonances of trytophan 3 and tyrosine 69 in bovine pancreatic phospholipase A2, its pro-enzyme and in Ala1-transaminated protein were assigned using photochemically-induced dynamic nuclear polarization (photo-CIDNP) as such or in combination with spin-echo measurements. In addition

  11. 1H-NMR and photochemically-induced dynamic nuclear polarization studies on bovine pancreatic phospholipase A2

    NARCIS (Netherlands)

    Egmond, M.R.; Slotboom, A.J.; Haas, G.H. de; Dijkstra, Klaas; Kaptein, R.

    1980-01-01

    Proton-NMR resonances of trytophan 3 and tyrosine 69 in bovine pancreatic phospholipase A2, its pro-enzyme and in Ala1-transaminated protein were assigned using photochemically-induced dynamic nuclear polarization (photo-CIDNP) as such or in combination with spin-echo measurements. In addition assig

  12. Alcohol-induced structural transitions in the acid-denatured Bacillus licheniformis α-amylase

    Directory of Open Access Journals (Sweden)

    Adyani Azizah Abd Halim

    2017-01-01

    Full Text Available Alcohol-induced structural changes in the acid-denatured Bacillus licheniformis α-amylase (BLA at pH 2.0 were studied by far-ultra violet circular dichroism, intrinsic, three-dimensional and 8-anilino-1-naphthalene sulfonic acid (ANS fluorescence, acrylamide quenching and thermal denaturation. All the alcohols used in this study produced partial refolding in the acid-denatured BLA as evident from the increased mean residue ellipticity at 222 nm, increased intrinsic fluorescence and decreased ANS fluorescence. The order of effectiveness of these alcohols to induce a partially folded state of BLA was found to be: 2,2,2-trifluoroethanol/tert-butanol > 1-propanol/2-propanol > 2-chloroethanol > ethanol > methanol. Three-dimensional fluorescence and acrylamide quenching results obtained in the presence of 5.5 M tert-butanol also suggested formation of a partially folded state in the acid-denatured BLA. However, 5.5 M tert-butanol-induced state of BLA showed a non-cooperative thermal transition. All these results suggested formation of a partially folded state of the acid-denatured BLA in the presence of these alcohols. Furthermore, their effectiveness was found to be guided by their chain length, position of methyl groups and presence of the substituents.

  13. miR-100 induces epithelial-mesenchymal transition but suppresses tumorigenesis, migration and invasion.

    Directory of Open Access Journals (Sweden)

    Dahu Chen

    2014-02-01

    Full Text Available Whether epithelial-mesenchymal transition (EMT is always linked to increased tumorigenicity is controversial. Through microRNA (miRNA expression profiling of mammary epithelial cells overexpressing Twist, Snail or ZEB1, we identified miR-100 as a novel EMT inducer. Surprisingly, miR-100 inhibits the tumorigenicity, motility and invasiveness of mammary tumor cells, and is commonly downregulated in human breast cancer due to hypermethylation of its host gene MIR100HG. The EMT-inducing and tumor-suppressing effects of miR-100 are mediated by distinct targets. While miR-100 downregulates E-cadherin by targeting SMARCA5, a regulator of CDH1 promoter methylation, this miRNA suppresses tumorigenesis, cell movement and invasion in vitro and in vivo through direct targeting of HOXA1, a gene that is both oncogenic and pro-invasive, leading to repression of multiple HOXA1 downstream targets involved in oncogenesis and invasiveness. These findings provide a proof-of-principle that EMT and tumorigenicity are not always associated and that certain EMT inducers can inhibit tumorigenesis, migration and invasion.

  14. Research of TGF-beta1 Inducing Lung Adencarcinoma PC9 Cells to Mesenchymal Cells Transition

    Directory of Open Access Journals (Sweden)

    Xiaofeng CHEN

    2010-01-01

    Full Text Available Background and objective It has been proven that epithelial-mesenchymal transition (EMT not only correlated with embryonic development but also could promote tumor invasion and metastasis. Transforming growth factor beta-1 (TGF-β1 has been identified as the main inducer of tumor EMT. The aim of this study was to investigate the effects of TGF-β1 on EMT and PI3K/AKT signaling pathway in lung adencarcinoma PC9 cells. Methods Cultured PC9 cells were treated with different concentrations of TGF-β1 for 48 h. The morphological changes were observed under phase-contrast microscopy; EMT relative marker protein changes were assessed by Western blot and immunoflurescence staining. In addition, the expression of AKT and P-AKT were also measured by Western blot. Results The data showed that TGF-β1 could induce PC9 morphological alteration from epithelial to mesenchymal and upregulate the expression of mesenchymal maker protein Fibronectin. Obviously, the expression of P-AKT was downregulated by TGF-β1 treatment for 48 h. Conclusion TGF-β1 might induce EMT of PC9 cells , accompanied by the changes of PI3K/AKT signaling pathway.

  15. FGFR4 promotes stroma-induced epithelial-to-mesenchymal transition in colorectal cancer.

    Science.gov (United States)

    Liu, Rui; Li, Jingyi; Xie, Ke; Zhang, Tao; Lei, Yunlong; Chen, Yi; Zhang, Lu; Huang, Kai; Wang, Kui; Wu, Hong; Wu, Min; Nice, Edouard C; Huang, Canhua; Wei, Yuquan

    2013-10-01

    Tumor cells evolve by interacting with the local microenvironment; however, the tumor-stroma interactions that govern tumor metastasis are poorly understood. In this study, proteomic analyses reveal that coculture with tumor-associated fibroblasts (TAF) induces significant overexpression of FGFR4, but not other FGFRs, in colorectal cancer cell lines. Mechanistic study shows that FGFR4 plays crucial roles in TAF-induced epithelial-to-mesenchymal transition (EMT) in colorectal cancer cell lines. Accumulated FGFR4 in cell membrane phosphorylates β-catenin, leading to translocation of β-catenin into the nucleus. Further, TAF-derived CCL2 and its downstream transcription factor, Ets-1, are prerequisites for TAF-induced FGFR4 upregulation. Furthermore, FGFR4-associated pathways are shown to be preferentially activated in colorectal tumor samples, and direct tumor metastasis in a mouse metastasis model. Our study shows a pivotal role of FGFR4 in tumor-stroma interactions during colorectal cancer metastasis, and suggests novel therapeutic opportunities for the treatment of colorectal cancer.

  16. Strain-induced ferroelectric phase transitions in incipient ferroelectric rutile TiO2

    Science.gov (United States)

    Ni, Li-Hong; Liu, Yong; Ren, Zhao-Hui; Song, Chen-Lu; Han, Gao-Rong

    2011-10-01

    Uniaxial strain induced ferroelectric phase transitions in rutile TiO2 are investigated by first-principles calculations. The calculated results show that the in-plane tensile strain induces rutile TiO2, paraelectric phase with P4-2/mnm(D4h) space group, to a ferroelectric phase with Pm(Cs) space group, driven by the softening behaviour of the Eu1 mode. In addition, the out-of-plane tensile strain, vertical to the ab plane, leads to a ferroelectric phase with P42nm (C4v) space group, driven by the softening behaviour of the A2u mode. The critical tensile strains are 3.7% in-plane and 4.0% out-of-plane, respectively. In addition, the in-plane compression strain, which has the same structure variation as out-of-plane tensile strain due to Poisson effect, leads the paraelectric rutile TiO2 to a paraelectric phase with Pnnm (D2h) space group driven by the softening behaviour of the B1g mode. These results indicate that the sequence ferroelectric (or paraelectric) phase depends on the strain applied. The origin of ferroelectric stabilization in rutile TiO2 is also discussed briefly in terms of strain induced Born effective charge transfer.

  17. Strain-induced ferroelectric phase transitions in incipient ferroelectric rutile TiO2

    Institute of Scientific and Technical Information of China (English)

    Ni Li-Hong; Liu Yong; Ren Zhao-Hui; Song Chen-Lu; Han Gao-Rong

    2011-01-01

    Uniaxial strain induced ferroelectric phase transitions in rutile TiO2 are investigated by flrnt-principles calculations.The calculated results show that the in-plane tensile strain induces rutile TiO2,paraelectric phase with P4-2/mnm (D4h) space group,to a ferroelectric phase with Pm(Cs) space group,driven by the softening behaviour of the Eul mode.In addition,the out-of-plane tensile strain,vertical to the ab plane,leads to a ferroelectric phase with P42nm (C4v) space group,driven by the softening behaviour of the A2u mode.The critical tensile strains are 3.7% in-plane and 4.0% out-of-plane,respectively.In addition,the in-plane compression strain,which has the same structure variation as outof-plane tensile strain due to Poisson effect,leads the paraelectric rutile TiO2 to a paraelectric phase with Pnnm (D2h) space group driven by the softening behaviour of the B1g mode.These results indicate that the sequence ferroelectric (or paraelectric) phase depends on the strain applied.The origin of ferroelectric stabilization in rutile TiO2 is also discussed briefly in terms of strain induced Born effective charge transfer.

  18. Resolving the H 2 effect on radiation induced dissolution of UO 2-based spent nuclear fuel

    Science.gov (United States)

    Trummer, Martin; Jonsson, Mats

    2010-01-01

    In recent years, the impact of H2 on α-radiation induced dissolution of UO2-based spent nuclear fuel has been studied and debated extensively. Experimental results on the effect of H2 on the concentration of H2O2 during α-radiolysis have been shown to disagree with numerical simulations. For this reason, the reaction scheme used in simulations of aqueous radiation chemistry has sometimes been questioned. In this work, we have studied the impact of H2 on the H2O2 concentration in α-irradiated aqueous solution using numerical simulations. The effects of H2 pressure, α-dose rate and HCO3- concentration were investigated by performing systematic variations in these parameters. The simulations show that the discrepancy between the previously published experimental result and numerical simulations is due to the use of a homogeneous dose rate (the energy is assumed to be equally distributed in the whole volume). Taking the actual dose rate of the α-irradiated volume into account, the simulation is in perfect agreement with the experimental results. This shows that the H2 effect is strongly α-dose rate dependent, and proves the reliability of the reaction scheme used in the simulations. The simulations also show that H2 influences the H2O2 concentration under α-radiolysis. The magnitude of the effect depends on the dose rate and the H2 pressure as well as on the concentration of HCO 3-. The impact of the radiolytic H2 effect on the rate of α-radiation induced dissolution of spent nuclear fuel is discussed along with other (α- and γ-) radiation induced processes capable of reducing the concentration of uranium in solution. The radiolytic H2 effect is quantitatively compared to the previously presented noble metal catalyzed H2 effect. This comparison shows that the noble metal catalyzed H2 effect is far more efficient than the radiolytic H2 effect. Reduction of U(VI) in solution due to low dose rate γ-radiolysis in the presence of H2 is proposed to be the cause of

  19. Quantum statistical model of nuclear multifragmentation in the canonical ensemble method 24.60.-k; 24.60.Ky; 25.70.Pq; 25.70.-z; Nuclear multifragmentation; First-order phase transition; Quantum statistics; Canonical ensemble

    CERN Document Server

    Parvan, A S; Ploszajczak, M

    2000-01-01

    A quantum statistical model of nuclear multifragmentation is proposed. The recurrence equation method used within the canonical ensemble makes the model solvable and transparent to physical assumptions and allows to get results without involving the Monte Carlo technique. The model exhibits the first-order phase transition. Quantum statistics effects are clearly seen on the microscopic level of occupation numbers but are almost washed out for global thermodynamic variables and the averaged observables studied. In the latter case, the recurrence relations for multiplicity distributions of both intermediate-mass and all fragments are derived and the specific changes in the shape of multiplicity distributions in the narrow region of the transition temperature is stressed. The temperature domain favorable to search for the HBT effect is noted.

  20. Polarization induced water molecule dissociation below the first-order electronic-phase transition temperature.

    Science.gov (United States)

    Das Arulsamy, Andrew; Kregar, Zlatko; Eleršič, Kristina; Modic, Martina; Subramani, Uma Shankar

    2011-09-01

    Hydrogen produced from the photocatalytic splitting of water is one of the reliable alternatives to replace the polluting fossil and the radioactive nuclear fuels. Here, we provide unequivocal evidence for the existence of blue- and red-shifting O-H covalent bonds within a single water molecule adsorbed on the MgO surface as a result of asymmetric displacement polarizabilities. The adsorbed H-O-H on MgO gives rise to one weaker H-O bond, while the other O-H covalent bond from the same adsorbed water molecule compensates this effect with a stronger bond. The weaker bond (nearest to the surface), the interlayer tunneling electrons and the silver substrate are shown to be the causes for the smallest dissociative activation energy on the MgO monolayer. The origin that is responsible to initiate the splitting mechanism is proven to be due to the changes in the polarizability of an adsorbed water molecule, which are further supported by the temperature-dependent static dielectric constant measurements for water below the first-order electronic-phase transition temperature.