Antisymmetrization effects and the form factor of the real part of the. cap alpha. -nucleus potential

DOE Office of Scientific and Technical Information (OSTI.GOV)

Majka, Z.; Budzanowski, A.; Grotowski, K.

1978-07-01

Antisymmetrization effects in the ..cap alpha..-nucleus interaction are investigated on the basis of a microscopic model in an one nucleon exchange approximation. It influences the form factor, increasing the halfway radius and decreasing the diffuseness as compared with the direct term of the potential only. Antisymmetrization preserves the shape of the potential which can be parametrized by a Woods-Saxon squared form. The phenomenological potential with the energy independent form factor of the above shape fits experimental data in a wide energy region.

Thermal modeling of Halley's comet

USGS Publications Warehouse

Weissman, P.R.; Kieffer, H.H.

1984-01-01

The comet thermal model of Weissman and Kieffer is used to calculate gas production rates and other parameters for the 1986 perihelion passage of Halley's Comet. Gas production estimates are very close to revised pre-perihelion estimates by Newburn based on 1910 observations of Halley; the increase in observed gas production post-perihelion may be explained by a variety of factors. The energy contribution from multiply scattered sunlight and thermal emission by coma dust increases the total energy reaching the Halley nucleus at perihelion by a factor of 2.4. The high obliquity of the Halley nucleus found by Sekanina and Larson may help to explain the asymmetry in Halley's gas production rates around perihelion. ?? 1984.

Oxytocin in the ventromedial hypothalamic nucleus reduces feeding and acutely increases energy expenditure

PubMed Central

Noble, Emily E.; Billington, Charles J.; Kotz, Catherine M.

2014-01-01

Central oxytocin reduces food intake and increases energy expenditure. The ventromedial hypothalamic nucleus (VMN) is associated with energy balance and contains a high density of oxytocin receptors. We hypothesized that oxytocin in the VMN is a negative regulator of energy balance acting to reduce feeding and increase energy expenditure. To test this idea, oxytocin or vehicle was injected directly into the VMN of Sprague-Dawley rats during fasted and nonfasted conditions. Energy expenditure (via indirect calorimetry) and spontaneous physical activity (SPA) were recorded simultaneously. Animals were also exposed to a conditioned taste aversion test, to determine whether oxytocin's effects on food intake were associated with malaise. When food was available during testing, oxytocin-induced elevations in energy expenditure lasted for 1 h, after which overall energy expenditure was reduced. In the absence of food during the testing period, oxytocin similarly increased energy expenditure during the first hour, but differences in 12-h energy expenditure were eliminated, implying that the differences may have been due to the thermic effects of feeding (digestion, absorption, and metabolic processing). Oxytocin acutely elevated SPA and reduced feeding at doses that did not cause a conditioned taste aversion during both the fed and fasted states. Together, these data suggest that oxytocin in the VMN promotes satiety and acutely elevates energy expenditure and SPA and implicates the VMN as a relevant site for the antiobesity effects of oxytocin. PMID:24990860

Two-proton capture on the 68Se nucleus with a new self-consistent cluster model

NASA Astrophysics Data System (ADS)

Hove, D.; Garrido, E.; Jensen, A. S.; Sarriguren, P.; Fynbo, H. O. U.; Fedorov, D. V.; Zinner, N. T.

2018-07-01

We investigate the two-proton capture reaction of the prominent rapid proton capture waiting point nucleus, 68Se, that produces the borromean nucleus 70Kr (68Se + p + p). We apply a recently formulated general model where the core nucleus, 68Se, is treated in the mean-field approximation and the three-body problem of the two valence protons and the core is solved exactly. We compare using two popular Skyrme interactions, SLy4 and SkM*. We calculate E2 electromagnetic two-proton dissociation and capture cross sections, and derive the temperature dependent capture rates. We vary the unknown 2+ resonance energy without changing any of the structures computed self-consistently for both core and valence particles. We find rates increasing quickly with temperature below 2-4 GK after which we find rates varying by about a factor of two independent of 2+ resonance energy. The capture mechanism is sequential through the f5/2 proton-core resonance, but the continuum background contributes significantly.

Forward-Backward Emission of Target Evaporated Fragments at High Energy Nucleus-Nucleus Collisions

NASA Astrophysics Data System (ADS)

Zhang, Zhi; Ma, Tian-Li; Zhang, Dong-Hai

The multiplicity distribution, multiplicity moments, scaled variance and entropy of target evaporated fragment emitted in forward and backward hemispheres in relativistic heavy ions induced emulsion heavy targets (AgBr) interactions are investigated. It is found that the multiplicity distribution can be fitted by the Gaussian distribution, and the fitting parameters are different between two hemispheres for all the interactions. The multiplicity moment increases with the order of the moment q, and second-order multiplicity moment is energy independent over the entire energy for all the interactions. The scaled variance is close to one for all the interactions. The entropy in forward hemisphere is greater than that in backward hemisphere for all the interactions.

Toward centrality determination at NICA/MPD

NASA Astrophysics Data System (ADS)

Galoyan, A. S.; Uzhinsky, V. V.

2017-03-01

Geometrical properties of nucleus-nucleus interactions at various centralities are calculated for the NICA energy range. A modified version of the Glauber Monte Carlo simulation code has been used for the calculations. It is shown that the geometrical properties of nucleus-nucleus interactions at the energies 5 - 10 GeV (NICA/MPD) and at energy 200 GeV (RHIC) are quite close to each other. A possible determination of centrality at NICA/MPD experiment using calculations of various Monte Carlo event generators are considered.

New Parameterization of Neutron Absorption Cross Sections

NASA Technical Reports Server (NTRS)

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

1997-01-01

Recent parameterization of absorption cross sections for any system of charged ion collisions, including proton-nucleus collisions, is extended for neutron-nucleus collisions valid from approx. 1 MeV to a few GeV, thus providing a comprehensive picture of absorption cross sections for any system of collision pairs (charged or uncharged). The parameters are associated with the physics of the problem. At lower energies, optical potential at the surface is important, and the Pauli operator plays an increasingly important role at intermediate energies. The agreement between the calculated and experimental data is better than earlier published results.

Dose enhancement effects to the nucleus and mitochondria from gold nanoparticles in the cytosol

PubMed Central

McNamara, AL; Kam, WW-Y; Scales, N; McMahon, SJ; Bennett, JW; Byrne, HL; Schuemann, J; Paganetti, H; Banati, R; Kuncic, Z

2016-01-01

Gold nanoparticles (GNPs) have shown potential as dose enhancers for radiation therapy. Since damage to the genome affects the viability of a cell, it is generally assumed that GNPs have to localise within the cell nucleus. In practice, however, GNPs tend to localise in the cytoplasm yet still appear to have a dose enhancing effect on the cell. Whether this effect can be attributed to stress-induced biological mechanisms or to physical damage to extra-nuclear cellular targets is still unclear. There is however growing evidence to suggest that the cellular response to radiation can also be influenced by indirect processes induced when the nucleus is not directly targeted by radiation. The mitochondrion in particular may be an effective extra-nuclear radiation target given its many important functional roles in the cell. To more accurately predict the physical effect of radiation within different cell organelles, we measured the full chemical composition of a whole human lymphocytic JURKAT cell as well as two separate organelles; the cell nucleus and the mitochondrion. The experimental measurements found that all three biological materials had similar ionisation energies ~ 70 eV, substantially lower than that of liquid water ~ 78 eV. Monte Carlo simulations for 10 – 50 keV incident photons showed higher energy deposition and ionisation numbers in the cell and organelle materials compared to liquid water. Adding a 1% mass fraction of gold to each material increased the energy deposition by a factor of ~ 1.8 when averaged over all incident photon energies. Simulations of a realistic compartmentalised cell show that the presence of gold in the cytosol increases the energy deposition in the mitochondrial volume more than within the nuclear volume. We find this is due to sub-micron delocalisation of energy by photoelectrons, making the mitochondria a potentially viable indirect radiation target for GNPs that localise to the cytosol. PMID:27435339

Possibility of synthesizing a doubly magic superheavy nucleus

NASA Astrophysics Data System (ADS)

Aritomo, Y.

2007-02-01

The possibility of synthesizing a doubly magic superheavy nucleus, 298114184, is investigated on the basis of fluctuation-dissipation dynamics. In order to synthesize this nucleus, we must generate more neutron-rich compound nuclei because of the neutron emissions from excited compound nuclei. The compound nucleus 304114 has two advantages to achieving a high survival probability. First, because of low neutron separation energy and rapid cooling, the shell correction energy recovers quickly. Secondly, owing to neutron emissions, the neutron number in the nucleus approaches that of the double closed shell and the nucleus attains a large fission barrier. Because of these two effects, the survival probability of 304114 does not decrease until the excitation energy E*=50 MeV. These properties lead to a rather high evaporation residue cross section.

PHENIX Measurements of Heavy Flavor in Small Systems

NASA Astrophysics Data System (ADS)

Lebedev, Alexandre

2018-01-01

The study of heavy flavor production in proton-nucleus and nucleus-nucleus collisions is a sensitive probe of the hot and dense matter created in such collisions. Installation of silicon vertex detectors in the PHENIX experiment, and increased performance of the BNL RHIC collider allowed collection of large amount of data on heavy flavor production in small colliding systems. In this talk we will present recent PHENIX results on open heavy flavor and quarkonia production in p+p, p+A, d+A, and He3+A colliding systems in a broad rapidity range, and discuss how these measurements help us to better understand all stages of nuclear collisions at high energy.

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

NASA Technical Reports Server (NTRS)

Norbury, John W.; Blattnig, Steve R.

2008-01-01

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

Dose enhancement effects to the nucleus and mitochondria from gold nanoparticles in the cytosol

NASA Astrophysics Data System (ADS)

McNamara, A. L.; Kam, W. W. Y.; Scales, N.; McMahon, S. J.; Bennett, J. W.; Byrne, H. L.; Schuemann, J.; Paganetti, H.; Banati, R.; Kuncic, Z.

2016-08-01

Gold nanoparticles (GNPs) have shown potential as dose enhancers for radiation therapy. Since damage to the genome affects the viability of a cell, it is generally assumed that GNPs have to localise within the cell nucleus. In practice, however, GNPs tend to localise in the cytoplasm yet still appear to have a dose enhancing effect on the cell. Whether this effect can be attributed to stress-induced biological mechanisms or to physical damage to extra-nuclear cellular targets is still unclear. There is however growing evidence to suggest that the cellular response to radiation can also be influenced by indirect processes induced when the nucleus is not directly targeted by radiation. The mitochondrion in particular may be an effective extra-nuclear radiation target given its many important functional roles in the cell. To more accurately predict the physical effect of radiation within different cell organelles, we measured the full chemical composition of a whole human lymphocytic JURKAT cell as well as two separate organelles; the cell nucleus and the mitochondrion. The experimental measurements found that all three biological materials had similar ionisation energies  ˜70 eV, substantially lower than that of liquid water  ˜78 eV. Monte Carlo simulations for 10-50 keV incident photons showed higher energy deposition and ionisation numbers in the cell and organelle materials compared to liquid water. Adding a 1% mass fraction of gold to each material increased the energy deposition by a factor of  ˜1.8 when averaged over all incident photon energies. Simulations of a realistic compartmentalised cell show that the presence of gold in the cytosol increases the energy deposition in the mitochondrial volume more than within the nuclear volume. We find this is due to sub-micron delocalisation of energy by photoelectrons, making the mitochondria a potentially viable indirect radiation target for GNPs that localise to the cytosol.

Results on ultra-relativistic nucleus-nucleus interactions from balloon-borne emulsion chambers

NASA Technical Reports Server (NTRS)

Burnett, T. H.; Dake, S.; Derrickson, J. H.; Fountain, W.; Meegan, C. A.; Takahashi, Y.; Watts, J. W.; Fuki, M.; Gregory, J. C.; Hayashi, T.

1985-01-01

The results of balloon-borne emulsion-chamber measurements on high-energy cosmic-ray nuclei (Burnett et al., 1983) are summarized in tables and graphs and briefly characterized. Special consideration is given to seven nucleus-nucleus interaction events at energy in excess of 1 TeV/A with multiplicity greater than 400, and to Fe interactions (53 with CHO, 10 with emulsion, and 14 with Pb) at 20-60 GeV/A.

Brain-derived neurotrophic factor in the nucleus tractus solitarii modulates glucose homeostasis after carotid chemoreceptor stimulation in rats.

PubMed

Montero, Sergio; Cuéllar, Ricardo; Lemus, Mónica; Avalos, Reyes; Ramírez, Gladys; de Álvarez-Buylla, Elena Roces

2012-01-01

Neuronal systems, which regulate energy intake, energy expenditure and endogenous glucose production, sense and respond to input from hormonal related signals that convey information from body energy availability. Carotid chemoreceptors (CChr) function as sensors for circulating glucose levels and contribute to glycemic counterregulatory responses. Brain-derived neurotrophic factor (BDNF) that plays an important role in the endocrine system to regulate glucose metabolism could play a role in hyperglycemic glucose reflex with brain glucose retention (BGR) evoked by anoxic CChr stimulation. Infusing BDNF into the nucleus tractus solitarii (NTS) before CChr stimulation, showed that this neurotrophin increased arterial glucose and BGR. In contrast, BDNF receptor (TrkB) antagonist (K252a) infusions in NTS resulted in a decrease in both glucose variables.

A study of the nucleus-nucleus total reaction cross section of stable systems at intermediate energies: An application to 12C

NASA Astrophysics Data System (ADS)

Hu, Liyuan; Song, Yushou; Hou, Yingwei; Liu, Huilan; Li, Hui

2018-07-01

A semi-microscopic analytical expression of the nucleus-nucleus total reaction cross section (σR) was proposed based on the strong absorption model. It is suitable for stable nuclei at intermediate energies. The matter density distributions of nuclei and the nucleon-nucleon total cross section were both considered. Particularly, the Fermi motion effect of the nucleons in a nucleus was also taken into account. The parametrization of σR was applied to the colliding systems including 12C. The experimental data at energies from 30 to 1000 MeV/nucleon were well reproduced, according to which an approach of deriving σR without adjustable parameters was developed. The necessity of considering the Fermi motion effect in the parametrization was discussed.

Enhancement of Feedback Efficiency by Active Galactic Nucleus Outflows via the Magnetic Tension Force in the Inhomogeneous Interstellar Medium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Asahina, Yuta; Ohsuga, Ken; Nomura, Mariko, E-mail: asahina@cfca.jp

By performing three-dimensional magnetohydrodynamics simulations of subrelativistic jets and disk winds propagating into the magnetized inhomogeneous interstellar medium (ISM), we investigate the magnetic effects on the active galactic nucleus feedback. Our simulations reveal that the magnetic tension force promotes the acceleration of the dense gas clouds, since the magnetic field lines, which are initially straight, bend around the gas clouds. In the jet models, the velocity dispersion of the clouds increases with an increase in the initial magnetic fields. The increment of the kinetic energy of the clouds is proportional to the initial magnetic fields, implying that the magnetic tensionmore » force increases the energy conversion efficiency from the jet to the gas clouds. Through simulations of the mildly collimated disk wind and the funnel-shaped disk wind, we confirm that such an enhancement of the energy conversion efficiency via the magnetic fields appears even if the energy is injected via the disk winds. The enhancement of the acceleration of the dense part of the magnetized ISM via the magnetic tension force will occur wherever the magnetized inhomogeneous matter is blown away.« less

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

NASA Technical Reports Server (NTRS)

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

1985-01-01

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

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

NASA Technical Reports Server (NTRS)

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

1985-01-01

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

Non-monotonic variations of the nucleation free energy in a glass-forming ultra-soft particles fluid.

PubMed

Desgranges, Caroline; Delhommelle, Jerome

2018-06-18

Using molecular dynamics simulation, we study the impact of the degree of supercooling on the crystal nucleation of ultra-soft particles, modeled with the Gaussian core potential. Focusing on systems with a high number density, our simulations reveal dramatically different behaviors as the degree of supercooling is varied. In the moderate supercooling regime, crystal nucleation proceeds as expected from classical nucleation theory, with a decrease in the free energy of nucleation, as well as in the size of the critical nucleus, as supercooling is increased. On the other hand, in the large supercooling regime, we observe an unusual reversal of behavior with an increase in the free energy of nucleation and in the critical size, as supercooling is increased. This unexpected result is analyzed in terms of the interplay between the glass transition and the crystal nucleation process. Specifically, medium range order crystal-like domains, with structural features different from that of the crystal nucleus, are found to form throughout the system when the supercooling is very large. These, in turn, play a pivotal role in the increase in the free energy of nucleation, as well as in the critical size, as the temperature gets closer to the glass transition.

Energy and Mass-Number Dependence of Hadron-Nucleus Total Reaction Cross Sections

NASA Astrophysics Data System (ADS)

Kohama, Akihisa; Iida, Kei; Oyamatsu, Kazuhiro

2016-09-01

We thoroughly investigate how proton-nucleus total reaction cross sections depend on the target mass number A and the proton incident energy. In doing so, we systematically analyze nuclear reaction data that are sensitive to nuclear size, namely, proton-nucleus total reaction cross sections and differential elastic cross sections, using a phenomenological black-sphere approximation of nuclei that we are developing. In this framework, the radius of the black sphere is found to be a useful length scale that simultaneously accounts for the observed proton-nucleus total reaction cross section and first diffraction peak in the proton elastic differential cross section. This framework, which is shown here to be applicable to antiprotons, is expected to be applicable to any kind of projectile that is strongly attenuated in the nucleus. On the basis of a cross-section formula constructed within this framework, we find that a less familiar A1/6 dependence plays a crucial role in describing the energy dependence of proton-nucleus total reaction cross sections.

Nucleus-nucleus interactions between 20 and 65 GeV per nucleon

NASA Technical Reports Server (NTRS)

Burnett, T. H.; Derrickson, J. H.; Fountain, W. F.; Meegan, C. A.; Parnell, T. A.; Roberts, F. E.; Watts, J. W.; Oda, H.; Takahashi, Y.; Jones, W. V.

1987-01-01

A hybrid electronic-counter/emulsion-chamber instrument was exposed to high-energy cosmic rays on a balloon. The data on 105 nucleus-nucleus collisions in the energy range 20-65 GeV/nucleon and for incident nuclear charges Zp in the range of 22 to 28 are presented. Inclusive characteristics of particle production on different targets (plastic, emulsion, and lead) are shown and compared with models based on the superposition of nucleon-nucleus interactions. Features of a subset of the more central collisions with a plastic target and some characteristics of individual events with the highest multiplicity of produced particles are described.

Photopions from nuclei in the distorted-wave impulse approximation

NASA Astrophysics Data System (ADS)

Girija, V.; Devanathan, V.

1982-11-01

The formalism for photoproduction of pions from nuclei has been developed in the distorted-wave impulse approximation, taking into account the effect of the change in pion momentum in nuclear medium. Detailed calculations have been done for the reaction 16O(γ, π+)16N for photon energies from 170 to 380 MeV, with a view to investigate the effect due to the gradient operator ∇-->π for momentum of the pion and test the sensitivity of the photopion cross sections to the details of the pion-nucleus optical potential. The results clearly establish that the gradient operator increases the cross sections throughout the energy region considered, the increase being small at lower energies. Also with ∇-->π, the cross sections are rendered less sensitive to the optical potential. The calculated differential cross sections agree very well with the recent experimental data of Shoda et al. for γ-ray energy of 200 MeV. However, the cross sections obtained at medium energies are higher when compared to the available experimental data. NUCLEAR REACTIONS π+ photoproduction from 16O; distorted wave impulse approximation; pion-nucleus optical potentials; gradient operator for the pion momentum.

Pancreatic polypeptide controls energy homeostasis via Npy6r signaling in the suprachiasmatic nucleus in mice.

PubMed

Yulyaningsih, Ernie; Loh, Kim; Lin, Shu; Lau, Jackie; Zhang, Lei; Shi, Yanchuan; Berning, Britt A; Enriquez, Ronaldo; Driessler, Frank; Macia, Laurence; Khor, Ee Cheng; Qi, Yue; Baldock, Paul; Sainsbury, Amanda; Herzog, Herbert

2014-01-07

Y-receptors control energy homeostasis, but the role of Npy6 receptors (Npy6r) is largely unknown. Young Npy6r-deficient (Npy6r(-/-)) mice have reduced body weight, lean mass, and adiposity, while older and high-fat-fed Npy6r(-/-) mice have low lean mass with increased adiposity. Npy6r(-/-) mice showed reduced hypothalamic growth hormone releasing hormone (Ghrh) expression and serum insulin-like growth factor-1 (IGF-1) levels relative to WT. This is likely due to impaired vasoactive intestinal peptide (VIP) signaling in the suprachiasmatic nucleus (SCN), where we found Npy6r coexpressed in VIP neurons. Peripheral administration of pancreatic polypeptide (PP) increased Fos expression in the SCN, increased energy expenditure, and reduced food intake in WT, but not Npy6r(-/-), mice. Moreover, intraperitoneal (i.p.) PP injection increased hypothalamic Ghrh mRNA expression and serum IGF-1 levels in WT, but not Npy6r(-/-), mice, an effect blocked by intracerebroventricular (i.c.v.) Vasoactive Intestinal Peptide (VPAC) receptors antagonism. Thus, PP-initiated signaling through Npy6r in VIP neurons regulates the growth hormone axis and body composition. Copyright © 2014 Elsevier Inc. All rights reserved.

The suprachiasmatic nucleus controls circadian energy metabolism and hepatic insulin sensitivity.

PubMed

Coomans, Claudia P; van den Berg, Sjoerd A A; Lucassen, Eliane A; Houben, Thijs; Pronk, Amanda C M; van der Spek, Rianne D; Kalsbeek, Andries; Biermasz, Nienke R; Willems van Dijk, Ko; Romijn, Johannes A; Meijer, Johanna H

2013-04-01

Disturbances in the circadian system are associated with the development of type 2 diabetes mellitus. Here, we studied the direct contribution of the suprachiasmatic nucleus (SCN), the central pacemaker in the circadian system, in the development of insulin resistance. Exclusive bilateral SCN lesions in male C57Bl/6J mice, as verified by immunochemistry, showed a small but significant increase in body weight (+17%), which was accounted for by an increase in fat mass. In contrast, mice with collateral damage to the ventromedial hypothalamus and paraventricular nucleus showed severe obesity and insulin resistance. Mice with exclusive SCN ablation revealed a loss of circadian rhythm in activity, oxygen consumption, and food intake. Hyperinsulinemic-euglycemic clamp analysis 8 weeks after lesioning showed that the glucose infusion rate was significantly lower in SCN lesioned mice compared with sham-operated mice (-63%). Although insulin potently inhibited endogenous glucose production (-84%), this was greatly reduced in SCN lesioned mice (-7%), indicating severe hepatic insulin resistance. Our data show that SCN malfunctioning plays an important role in the disturbance of energy balance and suggest that an absence of central clock activity, in a genetically intact animal, may lead to the development of insulin resistance.

High energy interactions of cosmic ray particles

NASA Technical Reports Server (NTRS)

Jones, L. W.

1986-01-01

The highlights of seven sessions of the Conference dealing with high energy interactions of cosmic rays are discussed. High energy cross section measurements; particle production-models of experiments; nuclei and nuclear matter; nucleus-nucleus collision; searches for magnetic monopoles; and studies of nucleon decay are covered.

Propagation of cosmic rays through the atmosphere in the quark-gluon strings model

NASA Technical Reports Server (NTRS)

Erlykin, A. D.; Krutikova, N. P.; Shabelski, Y. M.

1985-01-01

The quark-gluon strings model succeeds in the description of multiple hadron production in the central rapidity region of nucleon-nucleon interctions. This model was developed for hadron-nucleus interactions and used for calculation of the cosmic ray propagation through the atmosphere. It is shown that at energies 10 to the 11th power to the 12th power eV, this model gives a satisfactory description of experimental data. But with the increase of the energy up to approximately 10 to the 14th power eV, results of calculations and of experiments begin to differ and this difference rises with the energy. It may indicate that the scaling violation in the fragmentation region of inclusive spectra for hadron-nucleus interactions is stronger than in the quark-gluon strings model.

Charged-Particle Multiplicity Density at Midrapidity in Central Pb-Pb Collisions at sNN=2.76TeV

NASA Astrophysics Data System (ADS)

Aamodt, K.; Abelev, B.; Abrahantes Quintana, A.; Adamová, D.; Adare, A. M.; Aggarwal, M. M.; Aglieri Rinella, G.; Agocs, A. G.; Aguilar Salazar, S.; Ahammed, Z.; Ahmad Masoodi, A.; Ahmad, N.; Ahn, S. U.; Akindinov, A.; Aleksandrov, D.; Alessandro, B.; Alfaro Molina, R.; Alici, A.; Alkin, A.; Almaráz Aviña, E.; Alt, T.; Altini, V.; Altinpinar, S.; Altsybeev, I.; Andrei, C.; Andronic, A.; Anguelov, V.; Anson, C.; Antičić, T.; Antinori, F.; Antonioli, P.; Aphecetche, L.; Appelshäuser, H.; Arbor, N.; Arcelli, S.; Arend, A.; Armesto, N.; Arnaldi, R.; Aronsson, T.; Arsene, I. C.; Asryan, A.; Augustinus, A.; Averbeck, R.; Awes, T. C.; Äystö, J.; Azmi, M. D.; Bach, M.; Badalà, A.; Baek, Y. W.; Bagnasco, S.; Bailhache, R.; Bala, R.; Baldini Ferroli, R.; Baldisseri, A.; Baldit, A.; Baltasar Dos Santos Pedrosa, F.; Bán, J.; Barbera, R.; Barile, F.; Barnaföldi, G. G.; Barnby, L. S.; Barret, V.; Bartke, J.; Basile, M.; Bastid, N.; Bathen, B.; Batigne, G.; Batyunya, B.; Baumann, C.; Bearden, I. G.; Beck, H.; Belikov, I.; Bellini, F.; Bellwied, R.; Belmont-Moreno, E.; Beole, S.; Berceanu, I.; Bercuci, A.; Berdermann, E.; Berdnikov, Y.; Bergmann, C.; Betev, L.; Bhasin, A.; Bhati, A. K.; Bianchi, L.; Bianchi, N.; Bianchin, C.; Bielčík, J.; Bielčíková, J.; Bilandzic, A.; Biolcati, E.; Blanc, A.; Blanco, F.; Blanco, F.; Blau, D.; Blume, C.; Boccioli, M.; Bock, N.; Bogdanov, A.; Bøggild, H.; Bogolyubsky, M.; Boldizsár, L.; Bombara, M.; Bombonati, C.; Book, J.; Borel, H.; Borissov, A.; Bortolin, C.; Bose, S.; Bossú, F.; Botje, M.; Böttger, S.; Boyer, B.; Braun-Munzinger, P.; Bravina, L.; Bregant, M.; Breitner, T.; Broz, M.; Brun, R.; Bruna, E.; Bruno, G. E.; Budnikov, D.; Buesching, H.; Bugaiev, K.; Busch, O.; Buthelezi, Z.; Caffarri, D.; Cai, X.; Caines, H.; Calvo Villar, E.; Camerini, P.; Canoa Roman, V.; Cara Romeo, G.; Carena, F.; Carena, W.; Carminati, F.; Casanova Díaz, A.; Caselle, M.; Castillo Castellanos, J.; Catanescu, V.; Cavicchioli, C.; Cepila, J.; Cerello, P.; Chang, B.; Chapeland, S.; Charvet, J. L.; Chattopadhyay, S.; Chattopadhyay, S.; Cherney, M.; Cheshkov, C.; Cheynis, B.; Chiavassa, E.; Chibante Barroso, V.; Chinellato, D. D.; Chochula, P.; Chojnacki, M.; Christakoglou, P.; Christensen, C. H.; Christiansen, P.; Chujo, T.; Cicalo, C.; Cifarelli, L.; Cindolo, F.; Cleymans, J.; Coccetti, F.; Coffin, J.-P.; Coli, S.; Conesa Balbastre, G.; Conesa Del Valle, Z.; Constantin, P.; Contin, G.; Contreras, J. G.; Cormier, T. M.; Corrales Morales, Y.; Cortés Maldonado, I.; Cortese, P.; Cosentino, M. R.; Costa, F.; Cotallo, M. E.; Crescio, E.; Crochet, P.; Cuautle, E.; Cunqueiro, L.; Erasmo, G. D.; Dainese, A.; Dalsgaard, H. H.; Danu, A.; Das, D.; Das, I.; Das, K.; Dash, A.; Dash, S.; de, S.; de Azevedo Moregula, A.; de Barros, G. O. V.; de Caro, A.; de Cataldo, G.; de Cuveland, J.; de Falco, A.; de Gruttola, D.; de Marco, N.; de Pasquale, S.; de Remigis, R.; de Rooij, R.; Debski, P. R.; Del Castillo Sanchez, E.; Delagrange, H.; Delgado Mercado, Y.; Dellacasa, G.; Deloff, A.; Demanov, V.; Dénes, E.; Deppman, A.; di Bari, D.; di Giglio, C.; di Liberto, S.; di Mauro, A.; di Nezza, P.; Dietel, T.; Divià, R.; Djuvsland, Ø.; Dobrin, A.; Dobrowolski, T.; Domínguez, I.; Dönigus, B.; Dordic, O.; Driga, O.; Dubey, A. K.; Dubuisson, J.; Ducroux, L.; Dupieux, P.; Dutta Majumdar, A. K.; Dutta Majumdar, M. R.; Elia, D.; Emschermann, D.; Engel, H.; Erdal, H. A.; Espagnon, B.; Estienne, M.; Esumi, S.; Evans, D.; Evrard, S.; Eyyubova, G.; Fabjan, C. W.; Fabris, D.; Faivre, J.; Falchieri, D.; Fantoni, A.; Fasel, M.; Fearick, R.; Fedunov, A.; Fehlker, D.; Fekete, V.; Felea, D.; Feofilov, G.; Fernández Téllez, A.; Ferretti, A.; Ferretti, R.; Figiel, J.; Figueredo, M. A. S.; Filchagin, S.; Fini, R.; Finogeev, D.; Fionda, F. M.; Fiore, E. M.; Floris, M.; Foertsch, S.; Foka, P.; Fokin, S.; Fragiacomo, E.; Fragkiadakis, M.; Frankenfeld, U.; Fuchs, U.; Furano, F.; Furget, C.; Fusco Girard, M.; Gaardhøje, J. J.; Gadrat, S.; Gagliardi, M.; Gago, A.; Gallio, M.; Gangadharan, D. R.; Ganoti, P.; Ganti, M. S.; Garabatos, C.; Garcia-Solis, E.; Garishvili, I.; Gemme, R.; Gerhard, J.; Germain, M.; Geuna, C.; Gheata, A.; Gheata, M.; Ghidini, B.; Ghosh, P.; Gianotti, P.; Girard, M. R.; Giraudo, G.; Giubellino, P.; Gladysz-Dziadus, E.; Glässel, P.; Gomez, R.; Ferreiro, E. G.; González Santos, H.; González-Trueba, L. H.; González-Zamora, P.; Gorbunov, S.; Gotovac, S.; Grabski, V.; Grajcarek, R.; Grelli, A.; Grigoras, A.; Grigoras, C.; Grigoriev, V.; Grigoryan, A.; Grigoryan, S.; Grinyov, B.; Grion, N.; Gros, P.; Grosse-Oetringhaus, J. F.; Grossiord, J.-Y.; Grosso, R.; Guber, F.; Guernane, R.; Guerra Gutierrez, C.; Guerzoni, B.; Gulbrandsen, K.; Gunji, T.; Gupta, A.; Gupta, R.; Gutbrod, H.; Haaland, Ø.; Hadjidakis, C.; Haiduc, M.; Hamagaki, H.; Hamar, G.; Harris, J. W.; Hartig, M.; Hasch, D.; Hasegan, D.; Hatzifotiadou, D.; Hayrapetyan, A.; Heide, M.; Heinz, M.; Helstrup, H.; Herghelegiu, A.; Hernández, C.; Herrera Corral, G.; Herrmann, N.; Hetland, K. F.; Hicks, B.; Hille, P. T.; Hippolyte, B.; Horaguchi, T.; Hori, Y.; Hristov, P.; Hřivnáčová, I.; Huang, M.; Huber, S.; Humanic, T. J.; Hwang, D. S.; Ichou, R.; Ilkaev, R.; Ilkiv, I.; Inaba, M.; Incani, E.; Innocenti, G. M.; Innocenti, P. G.; Ippolitov, M.; Irfan, M.; Ivan, C.; Ivanov, A.; Ivanov, M.; Ivanov, V.; Jachołkowski, A.; Jacobs, P. M.; Jancurová, L.; Jangal, S.; Janik, R.; Jena, S.; Jirden, L.; Jones, G. T.; Jones, P. G.; Jovanović, P.; Jung, H.; Jung, W.; Jusko, A.; Kalcher, S.; Kaliňák, P.; Kalisky, M.; Kalliokoski, T.; Kalweit, A.; Kamermans, R.; Kanaki, K.; Kang, E.; Kang, J. H.; Kaplin, V.; Karavichev, O.; Karavicheva, T.; Karpechev, E.; Kazantsev, A.; Kebschull, U.; Keidel, R.; Khan, M. M.; Khan, S. A.; Khanzadeev, A.; Kharlov, Y.; Kileng, B.; Kim, D. J.; Kim, D. S.; Kim, D. W.; Kim, H. N.; Kim, J. H.; Kim, J. S.; Kim, M.; Kim, M.; Kim, S.; Kim, S. H.; Kirsch, S.; Kisel, I.; Kiselev, S.; Kisiel, A.; Klay, J. L.; Klein, J.; Klein-Bösing, C.; Kliemant, M.; Klovning, A.; Kluge, A.; Knichel, M. L.; Koch, K.; Köhler, M. K.; Kolevatov, R.; Kolojvari, A.; Kondratiev, V.; Kondratyeva, N.; Konevskih, A.; Kornaś, E.; Kottachchi Kankanamge Don, C.; Kour, R.; Kowalski, M.; Kox, S.; Koyithatta Meethaleveedu, G.; Kozlov, K.; Kral, J.; Králik, I.; Kramer, F.; Kraus, I.; Krawutschke, T.; Kretz, M.; Krivda, M.; Krizek, F.; Krumbhorn, D.; Krus, M.; Kryshen, E.; Krzewicki, M.; Kucheriaev, Y.; Kuhn, C.; Kuijer, P. G.; Kurashvili, P.; Kurepin, A.; Kurepin, A. B.; Kuryakin, A.; Kushpil, S.; Kushpil, V.; Kweon, M. J.; Kwon, Y.; La Rocca, P.; Ladrón de Guevara, P.; Lafage, V.; Lara, C.; Lardeux, A.; Larsen, D. T.; Lazzeroni, C.; Le Bornec, Y.; Lea, R.; Lee, K. S.; Lee, S. C.; Lefèvre, F.; Lehnert, J.; Leistam, L.; Lenhardt, M.; Lenti, V.; León Monzón, I.; León Vargas, H.; Lévai, P.; Li, X.; Lien, J.; Lietava, R.; Lindal, S.; Lindenstruth, V.; Lippmann, C.; Lisa, M. A.; Liu, L.; Loenne, P. I.; Loggins, V. R.; Loginov, V.; Lohn, S.; Loizides, C.; Loo, K. K.; Lopez, X.; López Noriega, M.; López Torres, E.; Løvhøiden, G.; Lu, X.-G.; Luettig, P.; Lunardon, M.; Luparello, G.; Luquin, L.; Luzzi, C.; Ma, K.; Ma, R.; Madagodahettige-Don, D. M.; Maevskaya, A.; Mager, M.; Mahapatra, D. P.; Maire, A.; Mal'Kevich, D.; Malaev, M.; Maldonado Cervantes, I.; Malinina, L.; Malzacher, P.; Mamonov, A.; Manceau, L.; Mangotra, L.; Manko, V.; Manso, F.; Manzari, V.; Mao, Y.; Mareš, J.; Margagliotti, G. V.; Margotti, A.; Marín, A.; Markert, C.; Martashvili, I.; Martinengo, P.; Martínez, M. I.; Martínez Davalos, A.; Martínez García, G.; Martynov, Y.; Masciocchi, S.; Masera, M.; Masoni, A.; Massacrier, L.; Mastromarco, M.; Mastroserio, A.; Matthews, Z. L.; Matyja, A.; Mayani, D.; Mayer, C.; Mazza, G.; Mazzoni, M. A.; Meddi, F.; Menchaca-Rocha, A.; Mendez Lorenzo, P.; Menis, I.; Mercado Pérez, J.; Meres, M.; Mereu, P.; Miake, Y.; Midori, J.; Milano, L.; Milosevic, J.; Mischke, A.; Miśkowiec, D.; Mitu, C.; Mlynarz, J.; Mohanty, A. K.; Mohanty, B.; Molnar, L.; Montaño Zetina, L.; Monteno, M.; Montes, E.; Morando, M.; Moreira de Godoy, D. A.; Moretto, S.; Morsch, A.; Muccifora, V.; Mudnic, E.; Muhuri, S.; Müller, H.; Munhoz, M. G.; Munoz, J.; Musa, L.; Musso, A.; Nandi, B. K.; Nania, R.; Nappi, E.; Nattrass, C.; Navach, F.; Navin, S.; Nayak, T. K.; Nazarenko, S.; Nazarov, G.; Nedosekin, A.; Nendaz, F.; Newby, J.; Nicassio, M.; Nielsen, B. S.; Niida, T.; Nikolaev, S.; Nikolic, V.; Nikulin, S.; Nikulin, V.; Nilsen, B. S.; Nilsson, M. S.; Noferini, F.; Nooren, G.; Novitzky, N.; Nyanin, A.; Nyatha, A.; Nygaard, C.; Nystrand, J.; Obayashi, H.; Ochirov, A.; Oeschler, H.; Oh, S. K.; Oleniacz, J.; Oppedisano, C.; Ortiz Velasquez, A.; Ortona, G.; Oskarsson, A.; Ostrowski, P.; Otterlund, I.; Otwinowski, J.; Oyama, K.; Ozawa, K.; Pachmayer, Y.; Pachr, M.; Padilla, F.; Pagano, P.; Jayarathna, S. P.; Paić, G.; Painke, F.; Pajares, C.; Pal, S.; Pal, S. K.; Palaha, A.; Palmeri, A.; Pappalardo, G. S.; Park, W. J.; Patalakha, D. I.; Paticchio, V.; Pavlinov, A.; Pawlak, T.; Peitzmann, T.; Peresunko, D.; Pérez Lara, C. E.; Perini, D.; Perrino, D.; Peryt, W.; Pesci, A.; Peskov, V.; Pestov, Y.; Peters, A. J.; Petráček, V.; Petran, M.; Petris, M.; Petrov, P.; Petrovici, M.; Petta, C.; Piano, S.; Piccotti, A.; Pikna, M.; Pillot, P.; Pinazza, O.; Pinsky, L.; Pitz, N.; Piuz, F.; Piyarathna, D. B.; Platt, R.; Płoskoń, M.; Pluta, J.; Pocheptsov, T.; Pochybova, S.; Podesta-Lerma, P. L. M.; Poghosyan, M. G.; Polák, K.; Polichtchouk, B.; Pop, A.; Porteboeuf, S.; Pospíšil, V.; Potukuchi, B.; Prasad, S. K.; Preghenella, R.; Prino, F.; Pruneau, C. A.; Pshenichnov, I.; Puddu, G.; Pulvirenti, A.; Punin, V.; Putiš, M.; Putschke, J.; Quercigh, E.; Qvigstad, H.; Rachevski, A.; Rademakers, A.; Rademakers, O.; Radomski, S.; Räihä, T. S.; Rak, J.; Rakotozafindrabe, A.; Ramello, L.; Ramírez Reyes, A.; Rammler, M.; Raniwala, R.; Raniwala, S.; Räsänen, S. S.; Read, K. F.; Real, J.; Redlich, K.; Renfordt, R.; Reolon, A. R.; Reshetin, A.; Rettig, F.; Revol, J.-P.; Reygers, K.; Ricaud, H.; Riccati, L.; Ricci, R. A.; Richter, M.; Riedler, P.; Riegler, W.; Riggi, F.; Rodríguez Cahuantzi, M.; Rohr, D.; Röhrich, D.; Romita, R.; Ronchetti, F.; Rosinský, P.; Rosnet, P.; Rossegger, S.; Rossi, A.; Roukoutakis, F.; Rousseau, S.; Roy, C.; Roy, P.; Rubio Montero, A. J.; Rui, R.; Rivetti, A.; Rusanov, I.; Ryabinkin, E.; Rybicki, A.; Sadovsky, S.; Šafařík, K.; Sahoo, R.; Sahu, P. K.; Saini, J.; Saiz, P.; Sakai, S.; Sakata, D.; Salgado, C. A.; Samanta, T.; Sambyal, S.; Samsonov, V.; Sanchez Castro, X.; Šándor, L.; Sandoval, A.; Sano, M.; Sano, S.; Santo, R.; Santoro, R.; Sarkamo, J.; Saturnini, P.; Scapparone, E.; Scarlassara, F.; Scharenberg, R. P.; Schiaua, C.; Schicker, R.; Schmidt, C.; Schmidt, H. R.; Schreiner, S.; Schuchmann, S.; Schukraft, J.; Schutz, Y.; Schwarz, K.; Schweda, K.; Scioli, G.; Scomparin, E.; Scott, P. A.; Scott, R.; Segato, G.; Selyuzhenkov, I.; Senyukov, S.; Seo, J.; Serci, S.; Serradilla, E.; Sevcenco, A.; Sgura, I.; Shabratova, G.; Shahoyan, R.; Sharma, N.; Sharma, S.; Shigaki, K.; Shimomura, M.; Shtejer, K.; Sibiriak, Y.; Siciliano, M.; Sicking, E.; Siemiarczuk, T.; Silenzi, A.; Silvermyr, D.; Simonetti, G.; Singaraju, R.; Singh, R.; Singhal, V.; Sinha, B. C.; Sinha, T.; Sitar, B.; Sitta, M.; Skaali, T. B.; Skjerdal, K.; Smakal, R.; Smirnov, N.; Snellings, R.; Søgaard, C.; Soloviev, A.; Soltz, R.; Son, H.; Song, J.; Song, M.; Soos, C.; Soramel, F.; Spyropoulou-Stassinaki, M.; Srivastava, B. K.; Stachel, J.; Stan, I.; Stefanek, G.; Stefanini, G.; Steinbeck, T.; Steinpreis, M.; Stenlund, E.; Steyn, G.; Stocco, D.; Stock, R.; Stokkevag, C. H.; Stolpovskiy, M.; Strmen, P.; Suaide, A. A. P.; Subieta Vásquez, M. A.; Sugitate, T.; Suire, C.; Sukhorukov, M.; Šumbera, M.; Susa, T.; Swoboda, D.; Symons, T. J. M.; Szanto de Toledo, A.; Szarka, I.; Szostak, A.; Tagridis, C.; Takahashi, J.; Tapia Takaki, J. D.; Tauro, A.; Tavlet, M.; Tejeda Muñoz, G.; Telesca, A.; Terrevoli, C.; Thäder, J.; Thomas, D.; Thomas, J. H.; Tieulent, R.; Timmins, A. R.; Tlusty, D.; Toia, A.; Torii, H.; Toscano, L.; Tosello, F.; Traczyk, T.; Truesdale, D.; Trzaska, W. H.; Tsuji, T.; Tumkin, A.; Turrisi, R.; Turvey, A. J.; Tveter, T. S.; Ulery, J.; Ullaland, K.; Uras, A.; Urbán, J.; Urciuoli, G. M.; Usai, G. L.; Vacchi, A.; Vajzer, M.; Vala, M.; Valencia Palomo, L.; Vallero, S.; van der Kolk, N.; van Leeuwen, M.; Vande Vyvre, P.; Vannucci, L.; Vargas, A.; Varma, R.; Vasileiou, M.; Vasiliev, A.; Vechernin, V.; Veldhoen, M.; Venaruzzo, M.; Vercellin, E.; Vergara, S.; Vernekohl, D. C.; Vernet, R.; Verweij, M.; Vickovic, L.; Viesti, G.; Vikhlyantsev, O.; Vilakazi, Z.; Villalobos Baillie, O.; Vinogradov, A.; Vinogradov, L.; Vinogradov, Y.; Virgili, T.; Viyogi, Y. P.; Vodopyanov, A.; Voloshin, K.; Voloshin, S.; Volpe, G.; von Haller, B.; Vranic, D.; Øvrebekk, G.; Vrláková, J.; Vulpescu, B.; Vyushin, A.; Wagner, B.; Wagner, V.; Wan, R.; Wang, D.; Wang, Y.; Wang, Y.; Watanabe, K.; Wessels, J. P.; Westerhoff, U.; Wiechula, J.; Wikne, J.; Wilde, M.; Wilk, A.; Wilk, G.; Williams, M. C. S.; Windelband, B.; Xaplanteris Karampatsos, L.; Yang, H.; Yang, S.; Yasnopolskiy, S.; Yi, J.; Yin, Z.; Yokoyama, H.; Yoo, I.-K.; Yu, W.; Yuan, X.; Yushmanov, I.; Zabrodin, E.; Zach, C.; Zampolli, C.; Zaporozhets, S.; Zarochentsev, A.; Závada, P.; Zaviyalov, N.; Zbroszczyk, H.; Zelnicek, P.; Zenin, A.; Zgura, I.; Zhalov, M.; Zhang, X.; Zhou, D.; Zichichi, A.; Zinovjev, G.; Zoccarato, Y.; Zynovyev, M.

2010-12-01

The first measurement of the charged-particle multiplicity density at midrapidity in Pb-Pb collisions at a center-of-mass energy per nucleon pair sNN=2.76TeV is presented. For an event sample corresponding to the most central 5% of the hadronic cross section, the pseudorapidity density of primary charged particles at midrapidity is 1584±4(stat)±76(syst), which corresponds to 8.3±0.4(syst) per participating nucleon pair. This represents an increase of about a factor 1.9 relative to pp collisions at similar collision energies, and about a factor 2.2 to central Au-Au collisions at sNN=0.2TeV. This measurement provides the first experimental constraint for models of nucleus-nucleus collisions at LHC energies.

The stark effect on the spectrum energy of tritium in first excited state with relativistic condition

NASA Astrophysics Data System (ADS)

Prastowo, S. H. B.; Supriadi, B.; Bahri, S.; Ridlo, Z. R.

2018-04-01

This research discussed about the correction of Stark Effect on Tritium atoms in the first excited state with relativistic conditions. The approach used to solve this Stark Effect correction was the perturbation theory which was from time independent degenerate perturbation theory to second-order correction. The Stark Effect on the excited state made the spectrum energy polarization of Tritium which was included in the isotope of hydrogen with an electron moving around the nucleus with high velocity. Hence, the relativistic correction affected the spectrum energy shift. Tritium was a radioactive material having half-time 12,3 years and relatively safe. The Tritium application was a material for the manufacture of nuclear battery. The most effective external electric field that should give to Tritium was 108 V/mith the total correction energy that was 0,97398557 × 10-21 Joule. Therefore, its effect reduced the binding energy between electron and nucleus, and increased the power of Tritium Betavoltaics Battery.

A search for the production of direct leptons in nucleon-nucleus and nucleus-nucleus collisions. [Intermediate Energy Nuclear Physics Group, Dept. of Physics and Astronomy, Louisiana State Univ. , Baton Rouge

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kirk, P.N.

1992-12-15

Activities included contributions to the AMY Collaboration, the transverse energy detector, the Di-Lepton Spectrometer, with emphasis on the single-lepton experiment. Elastic and inelastic scattering differential cross sections and total cross sections are shown for [pi][sup +] and [pi][sup [minus

Comparison of torsional and longitudinal modes using phacoemulsification parameters.

PubMed

Rekas, Marek; Montés-Micó, Robert; Krix-Jachym, Karolina; Kluś, Adam; Stankiewicz, Andrzej; Ferrer-Blasco, Teresa

2009-10-01

To compare phacoemulsification parameters of torsional and longitudinal ultrasound modes. Ophthalmology Department, Military Health Service Institute, Warsaw, Poland. This prospective study evaluated eyes 1, 7, and 30 days after phacoemulsification with an Infiniti Vision System using the torsional or longitudinal ultrasound (US) mode. Cataract classification was according to the Lens Opacities Classification System II. Nucleus fragmentation was by the phaco-chop and quick-chop methods. Primary outcome measures were phaco time, mean phaco power, mean torsional amplitude, and aspiration time. Total energy, defined as cumulative dissipated energy (CDE) x aspiration time, and the effective coefficient, defined as aspiration time/phaco time, were also calculated. Four hundred eyes were evaluated. The CDE was statistically significantly lower in the torsional mode for nucleus grades I, II, and III (P<.001) but not for grade IV (P>.05). Aspiration time was statistically significantly shorter in the torsional mode than in the longitudinal mode for nucleus grades III and IV (P<.05). Total energy was significantly lower in the torsional mode for all nucleus densities (P<.05). The effective coefficient was significantly lower in the longitudinal mode except for nucleus grade I (P<.05). Torsional phacoemulsification was more effective than longitudinal phacoemulsification in the amount of applied fluid and the quantity of US energy expended. With the torsional method, it was possible to maintain a constant ratio of amount of fluid flow to quantity of US energy used, regardless of nucleus density.

Topics in nuclear chromodynamics: Color transparency and hadronization in the nucleus

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brodsky, S.J.

1988-03-01

The nucleus plays two complimentary roles in quantum chromodynamics: (1) A nuclear target can be used as a control medium or background field to modify or probe quark and gluon subprocesses. Some novel examples are color transparency, the predicted transparency of the nucleus to hadrons participating in high momentum transfer exclusive reactions, and formation zone phenomena, the absence of hard, collinear, target-induced radiation by a quark or gluon interacting in a high momentum transfer inclusive reaction if its energy is large compared to a scale proportional to the length of the target. (Soft radiation and elastic initial state interactions inmore » the nucleus still occur.) Coalescence with co-moving spectators is discussed as a mechanism which can lead to increased open charm hadroproduction, but which also suppresses forward charmonium production (relative to lepton pairs) in heavy ion collisions. Also discussed are some novel features of nuclear diffractive amplitudes--high energy hadronic or electromagnetic reactions which leave the entire nucleus intact and give nonadditive contributions to the nuclear structure function at low /kappa cur//sub Bj/. (2) Conversely, the nucleus can be studied as a QCD structure. At short distances, nuclear wave functions and nuclear interactions necessarily involve hidden color, degrees of freedom orthogonal to the channels described by the usual nucleon or isobar degrees of freedom. At asymptotic momentum transfer, the deuteron form factor and distribution amplitude are rigorously calculable. One can also derive new types of testable scaling laws for exclusive nuclear amplitudes in terms of the reduced amplitude formalism.« less

Computer program for parameterization of nucleus-nucleus electromagnetic dissociation cross sections

NASA Technical Reports Server (NTRS)

Norbury, John W.; Townsend, Lawrence W.; Badavi, Forooz F.

1988-01-01

A computer subroutine parameterization of electromagnetic dissociation cross sections for nucleus-nucleus collisions is presented that is suitable for implementation in a heavy ion transport code. The only inputs required are the projectile kinetic energy and the projectile and target charge and mass numbers.

From cold to hot nuclear matter

NASA Astrophysics Data System (ADS)

Bratkovskaya, E. L.; Cassing, W.; Konchakovski, V. P.; Toneev, V. D.

2015-11-01

The dynamics of partons and hadrons in relativistic nucleus-nucleus collisions is analyzed within the Parton-Hadron-String Dynamics (PHSD) transport approach which is based on a dynamical quasiparticle model for the partonic phase (DQPM) including a dynamical hadronization scheme with covariant transition rates. The PHSD approach is applied to nucleus-nucleus collisions from FAIR/NICA to LHC energies. The traces of partonic interactions are found in particular in the directed and elliptic flow of hadrons and in their transverse mass spectra. Whereas at RHIC and LHC energies the dynamics is dominated by partonic degrees-of-freedom in the hot QGP, we find at FAIR/NICA energies a moderately hot but dense matter where chiral symmetry restoration and hadronic potentials appear to play a major role.

Study of the 190Hg Nucleus: Testing the Existence of U(5) Symmetry

NASA Astrophysics Data System (ADS)

Jahangiri Tazekand, Z.; Mohseni, M.; Mohammadi, M. A.; Sabri, H.

2018-06-01

In this paper, we have considered the energy spectra, quadrupole transition probabilities, energy surface, charge radii, and quadrupole moment of the190Hg nucleus to describe the interplay between phase transitions and configuration mixing of intruder excitations. To this aim, we have used four different formalisms: (i) interacting boson model including configuration mixing, (ii) Z(5) critical symmetry, (iii) U(6)-based transitional Hamiltonian, and (iv) a transitional interacting boson model Hamiltonian in both interacting boson model (IBM)-1 and IBM-2 versions which are based on affine \\widehat{SU(1,1)} Lie algebra. Results show the advantages of configuration mixing and transitional Hamiltonians, in particular IBM-2 formalism, to reproduce the experimental counterparts when the weight of spherical symmetry increased.

Energy dependence of the transverse momentum distributions of charged particles in pp collisions measured by ALICE.

PubMed

Abelev, B; Adam, J; Adamová, D; Adare, A M; Aggarwal, M M; Aglieri Rinella, G; Agnello, M; Agocs, A G; Agostinelli, A; Ahammed, Z; Ahmad, N; Ahmad Masoodi, A; Ahmed, I; Ahn, S A; Ahn, S U; Aimo, I; Aiola, S; Ajaz, M; Akindinov, A; Aleksandrov, D; Alessandro, B; Alexandre, D; Alici, A; Alkin, A; Alme, J; Alt, T; Altini, V; Altinpinar, S; Altsybeev, I; Alves Garcia Prado, C; Andrei, C; Andronic, A; Anguelov, V; Anielski, J; Antičić, T; Antinori, F; Antonioli, P; Aphecetche, L; Appelshäuser, H; Arbor, N; Arcelli, S; Armesto, N; Arnaldi, R; Aronsson, T; Arsene, I C; Arslandok, M; Augustinus, A; Averbeck, R; Awes, T C; Äystö, J; Azmi, M D; Bach, M; Badalà, A; Baek, Y W; Bailhache, R; Bala, R; Baldisseri, A; Baltasar Dos Santos Pedrosa, F; Bán, J; Baral, R C; Barbera, R; Barile, F; Barnaföldi, G G; Barnby, L S; Barret, V; Bartke, J; Basile, M; Bastid, N; Basu, S; Bathen, B; Batigne, G; Batyunya, B; Batzing, P C; Baumann, C; Bearden, I G; Beck, H; Bedda, C; Behera, N K; Belikov, I; Bellini, F; 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Chattopadhyay, S; Cherney, M; Cheshkov, C; Cheynis, B; Chibante Barroso, V; Chinellato, D D; Chochula, P; Chojnacki, M; Choudhury, S; Christakoglou, P; Christensen, C H; Christiansen, P; Chujo, T; Chung, S U; Cicalo, C; Cifarelli, L; Cindolo, F; Cleymans, J; Colamaria, F; Colella, D; Collu, A; Colocci, M; Conesa Balbastre, G; Conesa Del Valle, Z; Connors, M E; Contin, G; Contreras, J G; Cormier, T M; Corrales Morales, Y; Cortese, P; Cortés Maldonado, I; Cosentino, M R; Costa, F; Crochet, P; Cruz Albino, R; Cuautle, E; Cunqueiro, L; Dainese, A; Dang, R; Danu, A; Das, K; Das, D; Das, I; Dash, A; Dash, S; De, S; Delagrange, H; Deloff, A; Dénes, E; Deppman, A; de Barros, G O V; De Caro, A; de Cataldo, G; de Cuveland, J; De Falco, A; De Gruttola, D; De Marco, N; De Pasquale, S; de Rooij, R; Diaz Corchero, M A; Dietel, T; Divià, R; Di Bari, D; Di Giglio, C; Di Liberto, S; Di Mauro, A; Di Nezza, P; Djuvsland, Ø; Dobrin, A; Dobrowolski, T; Dönigus, B; Dordic, O; Dubey, A K; Dubla, A; Ducroux, L; Dupieux, P; Dutta Majumdar, A K; D Erasmo, G; Elia, D; Emschermann, D; Engel, H; Erazmus, B; Erdal, H A; Eschweiler, D; Espagnon, B; Estienne, M; Esumi, S; Evans, D; Evdokimov, S; Eyyubova, G; Fabris, D; Faivre, J; Falchieri, D; Fantoni, A; Fasel, M; Fehlker, D; Feldkamp, L; Felea, D; Feliciello, A; Feofilov, G; Fernández Téllez, A; Ferreiro, E G; Ferretti, A; Festanti, A; Figiel, J; Figueredo, M A S; Filchagin, S; Finogeev, D; Fionda, F M; Fiore, E M; Floratos, E; Floris, M; Foertsch, S; Foka, P; Fokin, S; Fragiacomo, E; Francescon, A; Frankenfeld, U; Fuchs, U; Furget, C; Fusco Girard, M; Gaardhøje, J J; Gagliardi, M; Gago, A; Gallio, M; Gangadharan, D R; Ganoti, P; Garabatos, C; Garcia-Solis, E; Gargiulo, C; Garishvili, I; Gerhard, J; Germain, M; Gheata, A; Gheata, M; Ghidini, B; Ghosh, P; Gianotti, P; Giubellino, P; Gladysz-Dziadus, E; Glässel, P; Goerlich, L; Gomez, R; González-Zamora, P; Gorbunov, S; Gotovac, S; Graczykowski, L K; Grajcarek, R; Grelli, A; Grigoras, C; Grigoras, A; Grigoriev, V; Grigoryan, A; Grigoryan, S; Grinyov, B; Grion, N; Grosse-Oetringhaus, J F; Grossiord, J-Y; Grosso, R; Guber, F; Guernane, R; Guerzoni, B; Guilbaud, M; Gulbrandsen, K; Gulkanyan, H; Gunji, T; Gupta, A; Gupta, R; Khan, K H; Haake, R; Haaland, Ø; Hadjidakis, C; Haiduc, M; Hamagaki, H; Hamar, G; Hanratty, L D; Hansen, A; Harris, J W; Harton, A; Hatzifotiadou, D; Hayashi, S; Hayrapetyan, A; Heckel, S T; Heide, M; Helstrup, H; Herghelegiu, A; Herrera Corral, G; Herrmann, N; Hess, B A; Hetland, K F; Hicks, B; Hippolyte, B; Hori, Y; Hristov, P; Hřivnáčová, I; Huang, M; Humanic, T J; Hutter, D; Hwang, D S; Ichou, R; Ilkaev, R; Ilkiv, I; Inaba, M; Incani, E; Innocenti, G M; Ionita, C; Ippolitov, M; Irfan, M; Ivanov, V; Ivanov, M; Ivanytskyi, O; Jachołkowski, A; Jahnke, C; Jang, H J; Janik, M A; Jayarathna, P H S Y; Jena, S; Jimenez Bustamante, R T; Jones, P G; Jung, H; Jusko, A; Kalcher, S; Kaliňák, P; Kalliokoski, T; Kalweit, A; Kang, J H; Kaplin, V; Kar, S; Karasu Uysal, A; Karavichev, O; Karavicheva, T; Karpechev, E; Kazantsev, A; Kebschull, U; Keidel, R; Ketzer, B; Khan, S A; Khan, M M; Khan, P; Khanzadeev, A; Kharlov, Y; Kileng, B; Kim, S; Kim, D W; Kim, D J; Kim, B; Kim, T; Kim, M; Kim, M; Kim, J S; Kirsch, S; Kisel, I; Kiselev, S; Kisiel, A; Kiss, G; Klay, J L; Klein, J; Klein-Bösing, C; Kluge, A; Knichel, M L; Knospe, A G; Köhler, M K; Kollegger, T; Kolojvari, A; Kondratiev, V; Kondratyeva, N; Konevskikh, A; Kovalenko, V; Kowalski, M; Kox, S; Koyithatta Meethaleveedu, G; Kral, J; Králik, I; Kramer, F; Kravčáková, A; Krelina, M; Kretz, M; Krivda, M; Krizek, F; Krus, M; Kryshen, E; Krzewicki, M; Kucera, V; Kucheriaev, Y; Kugathasan, T; Kuhn, C; Kuijer, P G; Kulakov, I; Kumar, J; Kurashvili, P; Kurepin, A B; Kurepin, A; Kuryakin, A; Kushpil, S; Kushpil, V; Kweon, M J; Kwon, Y; Ladrón de Guevara, P; Lagana Fernandes, C; Lakomov, I; Langoy, R; Lara, C; Lardeux, A; La Pointe, S L; La Rocca, P; Lea, R; Lechman, M; Lee, S C; Lee, G R; Legrand, I; Lehnert, J; Lemmon, R C; Lenhardt, M; Lenti, V; León Monzón, I; Lévai, P; Li, S; Lien, J; Lietava, R; Lindal, S; Lindenstruth, V; Lippmann, C; Lisa, M A; Ljunggren, H M; Lodato, D F; Loenne, P I; Loggins, V R; Loginov, V; Lohner, D; Loizides, C; Loo, K K; Lopez, X; López Torres, E; Løvhøiden, G; Lu, X-G; Luettig, P; Lunardon, M; Luo, J; Luparello, G; Luzzi, C; Jacobs, P M; Ma, R; Maevskaya, A; Mager, M; Mahapatra, D P; Maire, A; Malaev, M; Maldonado Cervantes, I; Malinina, L; Mal'Kevich, D; Malzacher, P; Mamonov, A; Manceau, L; Manko, V; Manso, F; Manzari, V; Marchisone, M; Mareš, J; Margagliotti, G V; Margotti, A; Marín, A; Markert, C; Marquard, M; Martashvili, I; Martin, N A; Martinengo, P; Martínez, M I; Martínez García, G; Martin Blanco, J; Martynov, Y; Mas, A; Masciocchi, S; Masera, M; Masoni, A; Massacrier, L; Mastroserio, A; Matyja, A; Mazer, J; Mazumder, R; Mazzoni, M A; Meddi, F; Menchaca-Rocha, A; Mercado Pérez, J; Meres, M; Miake, Y; Mikhaylov, K; Milano, L; Milosevic, J; Mischke, A; Mishra, A N; Miśkowiec, D; Mitu, C; Mlynarz, J; Mohanty, B; Molnar, L; Montaño Zetina, L; Monteno, M; Montes, E; Moon, T; Morando, M; Moreira De Godoy, D A; Moretto, S; Morreale, A; Morsch, A; Muccifora, V; Mudnic, E; Muhuri, S; Mukherjee, M; Müller, H; Munhoz, M G; Murray, S; Musa, L; Nandi, B K; Nania, R; Nappi, E; Nattrass, C; Nayak, T K; Nazarenko, S; Nedosekin, A; Nicassio, M; Niculescu, M; Nielsen, B S; Nikolaev, S; Nikulin, S; Nikulin, V; Nilsen, B S; Nilsson, M S; Noferini, F; Nomokonov, P; Nooren, G; Nyanin, A; Nyatha, A; Nystrand, J; Oeschler, H; Oh, S K; Oh, S; Olah, L; Oleniacz, J; Oliveira Da Silva, A C; Onderwaater, J; Oppedisano, C; Ortiz Velasquez, A; Oskarsson, A; Otwinowski, J; Oyama, K; Pachmayer, Y; Pachr, M; Pagano, P; Paić, G; Painke, F; Pajares, C; Pal, S K; Palaha, A; Palmeri, A; Papikyan, V; Pappalardo, G S; Park, W J; Passfeld, A; Patalakha, D I; Paticchio, V; Paul, B; Pawlak, T; Peitzmann, T; Pereira Da Costa, H; Pereira De Oliveira Filho, E; Peresunko, D; Pérez Lara, C E; Perrino, D; Peryt, W; Pesci, A; Pestov, Y; Petráček, V; Petran, M; Petris, M; Petrov, P; Petrovici, M; Petta, C; Piano, S; Pikna, M; Pillot, P; Pinazza, O; Pinsky, L; Pitz, N; Piyarathna, D B; Planinic, M; Płoskoń, M; Pluta, J; Pochybova, S; Podesta-Lerma, P L M; Poghosyan, M G; Polichtchouk, B; Poljak, N; Pop, A; Porteboeuf-Houssais, S; Pospíšil, V; Potukuchi, B; Prasad, S K; Preghenella, R; Prino, F; Pruneau, C A; Pshenichnov, I; Puddu, G; Punin, V; Putschke, J; Qvigstad, H; Rachevski, A; Rademakers, A; Rak, J; Rakotozafindrabe, A; Ramello, L; Raniwala, S; Raniwala, R; Räsänen, S S; Rascanu, B T; Rathee, D; Rauch, W; Rauf, A W; Razazi, V; Read, K F; Real, J S; Redlich, K; Reed, R J; Rehman, A; Reichelt, P; Reicher, M; Reidt, F; Renfordt, R; Reolon, A R; Reshetin, A; Rettig, F; Revol, J-P; Reygers, K; Riccati, L; Ricci, R A; Richert, T; Richter, M; Riedler, P; Riegler, W; Riggi, F; Rivetti, A; Rodríguez Cahuantzi, M; Rodriguez Manso, A; Røed, K; Rogochaya, E; Rohni, S; Rohr, D; Röhrich, D; Romita, R; Ronchetti, F; Rosnet, P; Rossegger, S; Rossi, A; Roy, P; Roy, C; Rubio Montero, A J; Rui, R; Russo, R; Ryabinkin, E; Rybicki, A; Sadovsky, S; Šafařík, K; Sahoo, R; Sahu, P K; Saini, J; Sakaguchi, H; Sakai, S; Sakata, D; Salgado, C A; Salzwedel, J; Sambyal, S; Samsonov, V; Sanchez Castro, X; Šándor, L; Sandoval, A; Sano, M; Santagati, G; Santoro, R; Sarkar, D; Scapparone, E; Scarlassara, F; Scharenberg, R P; Schiaua, C; Schicker, R; Schmidt, C; Schmidt, H R; Schuchmann, S; Schukraft, J; Schulc, M; Schuster, T; Schutz, Y; Schwarz, K; Schweda, K; Scioli, G; Scomparin, E; Scott, R; Scott, P A; Segato, G; Selyuzhenkov, I; Seo, J; Serci, S; Serradilla, E; Sevcenco, A; Shabetai, A; Shabratova, G; Shahoyan, R; Sharma, S; Sharma, N; Shigaki, K; Shtejer, K; Sibiriak, Y; Siddhanta, S; Siemiarczuk, T; Silvermyr, D; Silvestre, C; Simatovic, G; Singaraju, R; Singh, R; Singha, S; Singhal, V; Sinha, B C; Sinha, T; Sitar, B; Sitta, M; Skaali, T B; Skjerdal, K; Smakal, R; Smirnov, N; Snellings, R J M; Søgaard, C; Soltz, R; Song, M; Song, J; Soos, C; Soramel, F; Spacek, M; Sputowska, I; Spyropoulou-Stassinaki, M; Srivastava, B K; Stachel, J; Stan, I; Stefanek, G; Steinpreis, M; Stenlund, E; Steyn, G; Stiller, J H; Stocco, D; Stolpovskiy, M; Strmen, P; Suaide, A A P; Subieta Vásquez, M A; Sugitate, T; Suire, C; Suleymanov, M; Sultanov, R; Šumbera, M; Susa, T; Symons, T J M; Szanto de Toledo, A; Szarka, I; Szczepankiewicz, A; Szymański, M; Takahashi, J; Tangaro, M A; Tapia Takaki, J D; Tarantola Peloni, A; Tarazona Martinez, A; Tauro, A; Tejeda Muñoz, G; Telesca, A; Terrevoli, C; Ter Minasyan, A; Thäder, J; Thomas, D; Tieulent, R; Timmins, A R; Toia, A; Torii, H; Trubnikov, V; Trzaska, W H; Tsuji, T; Tumkin, A; Turrisi, R; Tveter, T S; Ulery, J; Ullaland, K; Ulrich, J; Uras, A; Urciuoli, G M; Usai, G L; Vajzer, M; Vala, M; Valencia Palomo, L; Vande Vyvre, P; Vannucci, L; Van Hoorne, J W; van Leeuwen, M; Vargas, A; Varma, R; Vasileiou, M; Vasiliev, A; Vechernin, V; Veldhoen, M; Venaruzzo, M; Vercellin, E; Vergara, S; Vernet, R; Verweij, M; Vickovic, L; Viesti, G; Viinikainen, J; Vilakazi, Z; Villalobos Baillie, O; Vinogradov, A; Vinogradov, L; Vinogradov, Y; Virgili, T; Viyogi, Y P; Vodopyanov, A; Völkl, M A; Voloshin, S; Voloshin, K; Volpe, G; von Haller, B; Vorobyev, I; Vranic, D; Vrláková, J; Vulpescu, B; Vyushin, A; Wagner, B; Wagner, V; Wagner, J; Wang, Y; Wang, Y; Wang, M; Watanabe, D; Watanabe, K; Weber, M; Wessels, J P; Westerhoff, U; Wiechula, J; Wikne, J; Wilde, M; Wilk, G; Wilkinson, J; Williams, M C S; Windelband, B; Winn, M; Xiang, C; Yaldo, C G; Yamaguchi, Y; Yang, H; Yang, P; Yang, S; Yano, S; Yasnopolskiy, S; Yi, J; Yin, Z; Yoo, I-K; Yushmanov, I; Zaccolo, V; Zach, C; Zampolli, C; Zaporozhets, S; Zarochentsev, A; Závada, P; Zaviyalov, N; Zbroszczyk, H; Zelnicek, P; Zgura, I S; Zhalov, M; Zhang, F; Zhang, Y; Zhang, H; Zhang, X; Zhou, D; Zhou, Y; Zhou, F; Zhu, X; Zhu, J; Zhu, J; Zhu, H; Zichichi, A; Zimmermann, M B; Zimmermann, A; Zinovjev, G; Zoccarato, Y; Zynovyev, M; Zyzak, M

Differential cross sections of charged particles in inelastic pp collisions as a function of p T have been measured at [Formula: see text] at the LHC. The p T spectra are compared to NLO-pQCD calculations. Though the differential cross section for an individual [Formula: see text] cannot be described by NLO-pQCD, the relative increase of cross section with [Formula: see text] is in agreement with NLO-pQCD. Based on these measurements and observations, procedures are discussed to construct pp reference spectra at [Formula: see text] up to p T =50 GeV/ c as required for the calculation of the nuclear modification factor in nucleus-nucleus and proton-nucleus collisions.

Search for critical point indications in long-range correlations by energy and system size scanning in string fusion approach

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kovalenko, V. N.; Vechernin, V. V.

2016-01-22

The ultrarelativistic collisions of heavy and light ions in the center-of-mass energy range from a few up to a hundred GeV per nucleon have been considered in string fusion approach. A Monte Carlo model of proton-proton, proton-nucleus, and nucleus-nucleus collisions has been developed, which takes into account both the string fusion and the finite rapidity length of strings, implementing the hadronic scattering through the interaction of color dipoles. It well describes the proton-nucleus and nucleus-nucleus collisions at the partonic level without using Glauber model of nuclear collisions. All parameters are fixed using experimental data on inelastic cross section and multiplicity.more » In the framework of the model, we performed a beam energy and system size scan and studied the behaviour of n-n, pt-n and pt-pt long-range correlation coefficients. The detailed modeling of the event by event charged particles production allowed to provide predictions in the conditions close to the experimental ones allowing a direct comparison to the data.« less

Heavy-flavour and quarkonium production in the LHC era: from proton-proton to heavy-ion collisions

DOE PAGES

Andronic, A.; Arleo, F.; Arnaldi, R.; ...

2016-02-29

This report reviews the study of open heavy-flavour and quarkonium production in high-energy hadronic collisions, as tools to investigate fundamental aspects of Quantum Chromodynamics, from the proton and nucleus structure at high energy to deconfinement and the properties of the Quark-Gluon Plasma. Emphasis is given to the lessons learnt from LHC Run 1 results, which are reviewed in a global picture with the results from SPS and RHIC at lower energies, as well as to the questions to be addressed in the future. The report covers heavy flavour and quarkonium production in proton-proton, proton-nucleus and nucleus-nucleus collisions. This includes discussionmore » of the effects of hot and cold strongly interacting matter, quarkonium photo-production in nucleus-nucleus collisions and perspectives on the study of heavy flavour and quarkonium with upgrades of existing experiments and new experiments. The report results from the activity of the SaporeGravis network of the I3 Hadron Physics programme of the European Union 7th Framework Programme.« less

Japanese-American Cooperative Emulsion Experiment /JACEE/. [high energy cosmic ray studies

NASA Technical Reports Server (NTRS)

Huggett, R. W.; Hunter, S. D.; Jones, W. V.; Takahashi, Y.; Ogata, T.; Saito, T.; Holynski, R.; Jurak, A.; Wolter, W.; Parnell, T. A.

1981-01-01

The instrumentation and results of long duration balloon flights carried out jointly by U.S. and Japan researchers to examine high energy cosmic rays are reported. Basic detector geometries are 2.5 sq m sr with operation at altitudes with 3-4 g/sq cm pressure, with observations thus far of over 100 hr. Energies from 2-100 TeV are recorded for nucleus-nucleus and hadron-nucleus interactions, and searches are made for new particle or interactions. The detector is an emulsion chamber which comprises doubly-coated nuclear emulsions on 800 micron thick methacryl substrates, X-ray films, etchable detectors, low density spacers, and lead sheets. Segmentation of the instrument into a primary charge module, a target section, a spacer section, and a lead-emulsion calorimeter allows accurate charge measurement for primary nuclei, reliable energy resolution, and a large geometrical factor for collecting high energy events. A primary Ca nucleus of 300 TeV has been observed.

Fission foil detector calibrations with high energy protons

NASA Technical Reports Server (NTRS)

Benton, E. V.; Frank, A. L.

1995-01-01

Fission foil detectors (FFD's) are passive devices composed of heavy metal foils in contact with muscovite mica films. The heavy metal nuclei have significant cross sections for fission when irradiated with neutrons and protons. Each isotope is characterized by threshold energies for the fission reactions and particular energy-dependent cross sections. In the FFD's, fission fragments produced by the reactions are emitted from the foils and create latent particle tracks in the adjacent mica films. When the films are processed surface tracks are formed which can be optically counted. The track densities are indications of the fluences and spectra of neutrons and/or protons. In the past, detection efficiencies have been calculated using the low energy neutron calibrated dosimeters and published fission cross sections for neutrons and protons. The problem is that the addition of a large kinetic energy to the (n,nucleus) or (p,nucleus) reaction could increase the energies and ranges of emitted fission fragments and increase the detector sensitivity as compared with lower energy neutron calibrations. High energy calibrations are the only method of resolving the uncertainties in detector efficiencies. At high energies, either proton or neutron calibrations are sufficient since the cross section data show that the proton and neutron fission cross sections are approximately equal. High energy proton beams have been utilized (1.8 and 4.9 GeV, 80 and 140 MeV) for measuring the tracks of fission fragments emitted backward and forward.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kirk, P.N.

1990-12-01

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

Momentum loss in proton-nucleus and nucleus-nucleus collisions

NASA Technical Reports Server (NTRS)

Khan, Ferdous; Townsend, Lawrence W.

1993-01-01

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

Peripherally administered baclofen reduced food intake and body weight in db/db as well as diet-induced obese mice.

PubMed

Sato, Ikuko; Arima, Hiroshi; Ozaki, Noriyuki; Ozaki, Nobuaki; Watanabe, Minemori; Goto, Motomitsu; Shimizu, Hiroshi; Hayashi, Masayuki; Banno, Ryouichi; Nagasaki, Hiroshi; Oiso, Yutaka

2007-10-16

Peripheral administration of baclofen significantly reduced food intake and body weight increase in both diabetic (db/db) and diet-induced obese mice for 5 weeks, whereas it had no significant effects on energy balance in their lean control mice. Despite the decreased body weight, neuropeptide Y expression in the arcuate nucleus was significantly decreased, whereas pro-opiomelanocortin expression was significantly increased by baclofen treatment. These data demonstrate that the inhibitory effects of baclofen on body weight in the obese mice were mediated via the arcuate nucleus at least partially, and suggest that GABA(B) agonists could be a new therapeutic reagent for obesity.

DNA Damage Dependence on the Subcellular Distribution of Low-Energy Beta Emitters

NASA Astrophysics Data System (ADS)

Cutaia, Claudia; Alloni, Daniele; Mariotti, Luca; Friedland, Werner; Ottolenghi, Andrea

One of the main issues of low-energy internal emitters is related to the short ranges of beta particles, compared to the dimensions of the biological targets (e.g. the cell nucleus). Also depending on the chemical form, the radionuclide may be more concentrated in the cytoplasm of the target cell (in our calculations a human fibroblast in interphase) and consequently the conventional dosimetry may overestimate the dose to the nucleus; whereas if the radionuclide is more concentrated in the nuclei of the cells there is a risk of underestimating the nucleus dose. The computer code PARTRAC was modified to calculate the energy depositions in the nucleus and the DNA damage for different relative concentrations of the radionuclide in the nucleus and in the cytoplasm. The nuclides considered in the simulations were Tritium (the electrons emitted due to the β - decay have an average energy of 5.7 keV, corresponding to an average range of 0.42 µm) and Nickel-63 (the electrons emitted have an average energy of 17 keV corresponding to an average range of 5 µm). In the case of Tritium, the dose in the nucleus due the tracks generated outside this region is 15% of the average dose in the cell, whereas in the case of Nickel-63 the dose in the nucleus resulted to be 64% of the average dose in the cell. The distributions of DNA fragments as a function of the relative concentration of the nuclides in the nucleus and in the cytoplasm, were also calculated. In the same conditions, the number of complex lesions (which have a high probability of inducing lethal damage to the cells) per Gy (circa 0.5-1) and the total number of double strand breaks (DSBs) per Gy (circa 40) were also calculated. To complete the characterization of the effects of internal emitters inside the cell the distributions of DSBs per chromosome were studied for different radionuclide distributions in the cell. The results obtained from these simulations show the possible overestimation or underestimation of the risk, (particularly for Tritium intake), due to the distribution of the low energy emitters at subcellular levels.

Shadowing effects on J/ψ and Υ production at energies available at the CERN Large Hadron Collider

DOE PAGES

Vogt, R.

2015-09-17

Proton-nucleus collisions have been used as a intermediate baseline for the determination of cold medium effects. They lie between proton-proton collisions in vacuum and nucleus-nucleus collisions which are expected to be dominated by hot matter effects. Modifications of the quark densities in nuclei relative to those of the proton are well established although those of the gluons in the nucleus are not well understood. We focus on the effect of these on quarkonium production in proton-lead collisions at the LHC at a center of mass energy of 5.02 TeV.

Experimental study of the isovector giant dipole resonance in 80Zr and 81Rb

NASA Astrophysics Data System (ADS)

Ceruti, S.; Camera, F.; Bracco, A.; Mentana, A.; Avigo, R.; Benzoni, G.; Blasi, N.; Bocchi, G.; Bottoni, S.; Brambilla, S.; Crespi, F. C. L.; Giaz, A.; Leoni, S.; Million, B.; Morales, A. I.; Nicolini, R.; Pellegri, L.; Riboldi, S.; Wieland, O.; Bazzacco, D.; Ciemala, M.; Farnea, E.; Gottardo, A.; Kmiecik, M.; Maj, A.; Mengoni, D.; Michelagnoli, C.; Modamio, V.; Montanari, D.; Napoli, D.; Recchia, F.; Sahin, E.; Ur, C.; Valiente-Dobón, J. J.; Wasilewska, B.; Zieblinski, M.

2017-01-01

The isovector giant dipole resonance (IVGDR) γ decay was measured in the compound nuclei 80Zr and 81Rb at an excitation energy of E*=54 MeV. The fusion reaction 40Ca+40Ca at Ebeam=136 MeV was used to form the compound nucleus 80Zr, while the reaction 37Cl+44Ca at Ebeam=95 MeV was used to form the compound nucleus 81Rb at the same excitation energy. The IVGDR parameters extracted from the analysis were compared with the ones found at higher excitation energy (E*=83 MeV). The comparison allows one to observe two different nuclear mechanisms: (i) the IVGDR intrinsic width remains constant with the excitation energy in the nucleus 81Rb; (ii) the isospin-violating spreading width (i.e., Coulomb spreading width) remains constant with the excitation energy in the nucleus 80Zr. The experimental setup used for the γ -ray detection was composed by the AGATA demonstrator array coupled to the large-volume LaBr3:Ce detectors of the HECTOR+ array.

Central Sirt1 regulates body weight and energy expenditure along with the POMC-derived peptide α-MSH and the processing enzyme CPE production in diet-induced obese male rats.

PubMed

Cyr, Nicole E; Steger, Jennifer S; Toorie, Anika M; Yang, Jonathan Z; Stuart, Ronald; Nillni, Eduardo A

2015-03-01

In the periphery, the nutrient-sensing enzyme Sirtuin 1 (silent mating type information regulation 2 homolog 1 [Sirt1]) reduces body weight in diet-induced obese (DIO) rodents. However, the role of hypothalamic Sirt1 in body weight and energy balance regulation is debated. The first studies to reveal that central Sirt1 regulates body weight came from experiments in our laboratory using Sprague-Dawley rats. Central inhibition of Sirt1 decreased body weight and food intake as a result of a forkhead box protein O1 (FoxO1)-mediated increase in the anorexigenic proopiomelanocortin (POMC) and decrease in the orexigenic Agouti-related peptide in the hypothalamic arcuate nucleus. Here, we demonstrate that central inhibition of Sirt1 in DIO decreased body weight and increased energy expenditure at higher levels as compared with the lean counterpart. Brain Sirt1 inhibition in DIO increased acetylated FoxO1, which in turn increased phosphorylated FoxO1 via improved insulin/phosphorylated AKT signaling. Elevated acetylated FoxO1 and phosphorylated FoxO1 increased POMC along with the α-melanocyte-stimulating hormone (α-MSH) maturation enzyme carboxypeptidase E, which resulted in more of the bioactive POMC product α-MSH released into the paraventricular nucleus. Increased in α-MSH led to augmented TRH levels and circulating T3 levels (triiodothyronine, thyroid hormone). These results indicate that inhibiting hypothalamic Sirt1 in DIO enhances the activity of the hypothalamic-pituitary-thyroid axis, which stimulates energy expenditure. Because we show that blocking central Sirt1 causes physiological changes that promote a negative energy balance in an obese individual, our results support brain Sirt1 as a significant target for weight loss therapeutics.

Central Sirt1 regulates body weight and energy expenditure along with the POMC-derived peptide α-MSH and the processing enzyme CPE production in diet-induced obese male rats.

PubMed

Cyr, Nicole E; Steger, Jennifer S; Toorie, Anika M; Yang, Jonathan Z; Stuart, Ronald; Nillni, Eduardo A

2014-07-01

In the periphery, the nutrient-sensing enzyme Sirtuin 1 (silent mating type information regulation 2 homolog 1 [Sirt1]) reduces body weight in diet-induced obese (DIO) rodents. However, the role of Sirt1 in the brain, particularly the hypothalamus, in body weight and energy balance regulation is debated. Among the first studies to reveal that central Sirt1 regulates body weight came from experiments in our laboratory using Sprague Dawley rats. In that study, central inhibition of Sirt1 decreased body weight and food intake as a result of a Forkhead box protein O1 (FoxO1)-mediated increase in the anorexigenic proopiomelanocortin (POMC) and decrease in the orexigenic Agouti-related peptide in the hypothalamic arcuate nucleus. Here, we demonstrate that central inhibition of Sirt1 in DIO decreased body weight and increased energy expenditure at higher levels as compared with the lean counterpart. Brain Sirt1 inhibition in DIO increased acetylated FoxO1, which, in turn, increased phosphorylated FoxO1 via improved insulin/pAKT signaling. Elevated acetylated FoxO1 and phosphorylated FoxO1 increased POMC along with the α-MSH maturation enzyme carboxypeptidase E, which resulted in more of the bioactive POMC product α-MSH released into the paraventricular nucleus. Increased in α-MSH led to augmented TRH levels and circulating T3 levels (thyroid hormone). These results indicate that inhibiting hypothalamic Sirt1 in DIO enhances the activity of the hypothalamic-pituitary-thyroid axis, which stimulates energy expenditure. Because we show that blocking central Sirt1 causes physiological changes that promote a negative energy balance in an obese individual, our results support brain Sirt1 as a significant target for weight loss therapeutics.

Thermal modeling of cometary nuclei

NASA Astrophysics Data System (ADS)

Weissman, P. R.; Kieffer, H. H.

1981-09-01

A model of the sublimation of volatile ices from a cometary nucleus is presented which includes the effects of (1) diurnal heating and cooling, (2) rotation period and pole orientation, (3) the thermal properties of the ice and subsurface layers, and (4) the contributions from coma opacity, scattering and thermal emission where the properties of the coma are derived from the integrated rate of volatile production by the nucleus. In applying the model to the case of the 1986 apparition of Halley's comet, it is found that the generation of a cometary dust coma increases the total energy reaching the Halley nucleus due to the greater geometrical cross-section of the coma as compared with the bare nucleus. The calculated coma opacity of Halley is about 0.2 at 1 AU from the sun and 1.2 at perihelion. Possible consequences of the results obtained for the generation of nongravitational forces, volatile production rates for comets and cometary lifetimes against sublimation are discussed.

Universal Parameterization of Absorption Cross Sections

NASA Technical Reports Server (NTRS)

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

1997-01-01

This paper presents a simple universal parameterization of total reaction cross sections for any system of colliding nuclei that is valid for the entire energy range from a few AMeV to a few AGeV. The universal picture presented here treats proton-nucleus collision as a special case of nucleus-nucleus collision, where the projectile has charge and mass number of one. The parameters are associated with the physics of the collision system. In general terms, Coulomb interaction modifies cross sections at lower energies, and the effects of Pauli blocking are important at higher energies. The agreement between the calculated and experimental data is better than all earlier published results.

Arcuate NPY neurons sense and integrate peripheral metabolic signals to control feeding.

PubMed

Kohno, Daisuke; Yada, Toshihiko

2012-12-01

NPY neuron in the hypothalamic arcuate nucleus is a key feeding center. Studies have shown that NPY neuron in the arcuate nucleus has a role to induce food intake. The arcuate nucleus is structurally unique with lacking blood brain barrier. Peripheral energy signals including hormones and nutrition can reach the arcuate nucleus. In this review, we discuss sensing and integrating peripheral signals in NPY neurons. In the arcuate nucleus, ghrelin mainly activates NPY neurons. Leptin and insulin suppress the ghrelin-induced activation in 30-40% of the ghrelin-activated NPY neurons. Lowering glucose concentration activates 40% of NPY neurons. These results indicate that NPY neuron in the arcuate nucleus is a feeding center in which major peripheral energy signals are directly sensed and integrated. Furthermore, there are subpopulations of NPY neurons in regard to their responsiveness to peripheral signals. These findings suggest that NPY neuron in the arcuate nucleus is an essential feeding center to induce food intake in response to peripheral metabolic state. Copyright © 2012 Elsevier Ltd. All rights reserved.

EPPS16: nuclear parton distributions with LHC data.

PubMed

Eskola, Kari J; Paakkinen, Petja; Paukkunen, Hannu; Salgado, Carlos A

2017-01-01

We introduce a global analysis of collinearly factorized nuclear parton distribution functions (PDFs) including, for the first time, data constraints from LHC proton-lead collisions. In comparison to our previous analysis, EPS09, where data only from charged-lepton-nucleus deep inelastic scattering (DIS), Drell-Yan (DY) dilepton production in proton-nucleus collisions and inclusive pion production in deuteron-nucleus collisions were the input, we now increase the variety of data constraints to cover also neutrino-nucleus DIS and low-mass DY production in pion-nucleus collisions. The new LHC data significantly extend the kinematic reach of the data constraints. We now allow much more freedom for the flavor dependence of nuclear effects than in other currently available analyses. As a result, especially the uncertainty estimates are more objective flavor by flavor. The neutrino DIS plays a pivotal role in obtaining a mutually consistent behavior for both up and down valence quarks, and the LHC dijet data clearly constrain gluons at large momentum fraction. Mainly for insufficient statistics, the pion-nucleus DY and heavy-gauge-boson production in proton-lead collisions impose less visible constraints. The outcome - a new set of next-to-leading order nuclear PDFs called EPPS16 - is made available for applications in high-energy nuclear collisions.

Simulation of Energy Response of the ATIC Calorimeter

NASA Technical Reports Server (NTRS)

Batkov, K. E.; Adams, J. H., Jr.; Ahn, H. S.; Bashindzhagyan, G. L.; Case, G.; Christl, M.; Chang, J.; Fazely, A. R.; Ganel, O.; Granger, D.;

Acoustic vibration effects in classical nucleation theory

NASA Astrophysics Data System (ADS)

Baird, James K.; Su, C.-H.

2018-04-01

Acoustic vibration is often used to improve the yield of crystals and nanoparticles growing from solutions and melts. As there is still a debate on how acoustic vibration actually works, we have examined the possibility that acoustic pressure can affect the rate of nucleation. Our method is based on an expansion of the free energy of the nucleus in powers of the acoustic pressure. With the assumption that the period of the sound wave is short as compared to the time scale for nucleation, we replace the powers of the acoustic pressure by their time averages, retaining the average of the square of the acoustic pressure as the leading term. By assuming a nucleus having spherical shape, we use the Young-Laplace equation to relate the pressure inside the nucleus to the ambient pressure. Without making further approximations not already standard in classical nucleation theory, we find that the proximate effect of acoustic pressure is to reduce both the size of the critical nucleus as well as the work required to form it from monomers. As the work serves as the activation energy, the ultimate effect of acoustic pressure is to increase the rate of nucleation. If we assume that the atomic structure of the nucleus is the same as that of an ordinary solid, however, we find the compressibility is too small for acoustic vibration effects to be noticeable. If on the other hand, we assume that the structure is similar to that of a loosely bound colloidal particle, then the effects of acoustic vibration become potentially observable.

Nucleus-size pinning for determination of nucleation free-energy barriers and nucleus geometry

NASA Astrophysics Data System (ADS)

Sharma, Abhishek K.; Escobedo, Fernando A.

2018-05-01

Classical Nucleation Theory (CNT) has recently been used in conjunction with a seeding approach to simulate nucleation phenomena at small-to-moderate supersaturation conditions when large free-energy barriers ensue. In this study, the conventional seeding approach [J. R. Espinosa et al., J. Chem. Phys. 144, 034501 (2016)] is improved by a novel, more robust method to estimate nucleation barriers. Inspired by the interfacial pinning approach [U. R. Pedersen, J. Chem. Phys. 139, 104102 (2013)] used before to determine conditions where two phases coexist, the seed of the incipient phase is pinned to a preselected size to iteratively drive the system toward the conditions where the seed becomes a critical nucleus. The proposed technique is first validated by estimating the critical nucleation conditions for the disorder-to-order transition in hard spheres and then applied to simulate and characterize the highly non-trivial (prolate) morphology of the critical crystal nucleus in hard gyrobifastigia. A generalization of CNT is used to account for nucleus asphericity and predict nucleation free-energy barriers for gyrobifastigia. These predictions of nuclei shape and barriers are validated by independent umbrella sampling calculations.

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

NASA Technical Reports Server (NTRS)

Cheung, Wang K.; Norbury, John W.

1994-01-01

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

Thiamine Deficiency Induces Anorexia by Inhibiting Hypothalamic AMPK

PubMed Central

Liu, Mei; Alimov, Alexander; Wang, Haiping; Frank, Jacqueline A.; Katz, Wendy; Xu, Mei; Ke, Zun-Ji; Luo, Jia

2014-01-01

Obesity and eating disorders are prevailing health concerns worldwide. It is important to understand the regulation of food intake and energy metabolism. Thiamine (vitamin B1) is an essential nutrient. Thiamine deficiency (TD) can cause a number of disorders in humans, such as Beriberi and Wernicke-Korsakoff syndrome. We demonstrated here that TD caused anorexia in C57BL/6 mice. After feeding a TD diet for 16 days, the mice displayed a significant decrease in food intake and an increase in resting energy expenditure (REE), which resulted in a severe weight loss. At the 22nd day, the food intake was reduced by 69% and 74% for male and female mice, respectively in TD group. The REE increased by 9 folds in TD group. The loss of body weight (17–24%) was similar between male and female animals and mainly resulted from the reduction of fat mass (49% decrease). Re-supplementation of thiamine (benfotiamine) restored animal's appetite, leading to a total recovery of body weight. The hypothalamic AMPK is a critical regulator of food intake. TD inhibited the phosphorylation of AMPK in the arcuate nucleus (ARN) and paraventricular nucleus (PVN) of the hypothalamus without affecting its expression. TD-induced inhibition of AMPK phosphorylation was reversed once thiamine was re-supplemented. In contrast, TD increased AMPK phosphorylation in the skeletal muscle and upregulated the uncoupling protein (UCP)-1 in brown adipose tissues which was consistent with increased basal energy expenditure. Re-administration of thiamine stabilized AMPK phosphorylation in the skeletal muscle as well as energy expenditure. Taken together, TD may induce anorexia by inhibiting hypothalamic AMPK activity. With a simultaneous increase in energy expenditure, TD caused an overall body weight loss. The results suggest that the status of thiamine levels in the body may affect food intake and body weight. PMID:24607345

Universal functions of nuclear proximity potential for Skyrme nucleus-nucleus interaction in a semiclassical approach

NASA Astrophysics Data System (ADS)

Gupta, Raj K.; Singh, Dalip; Kumar, Raj; Greiner, Walter

2009-07-01

The universal function of the nuclear proximity potential is obtained for the Skyrme nucleus-nucleus interaction in the semiclassical extended Thomas-Fermi (ETF) approach. This is obtained as a sum of the spin-orbit-density-independent and spin-orbit-density-dependent parts of the Hamiltonian density, since the two terms behave differently, the spin-orbit-density-independent part mainly attractive and the spin-orbit-density-dependent part mainly repulsive. The semiclassical expansions of kinetic energy density and spin-orbit density are allowed up to second order, and the two-parameter Fermi density, with its parameters fitted to experiments, is used for the nuclear density. The universal functions or the resulting nuclear proximity potential reproduce the 'exact' Skyrme nucleus-nucleus interaction potential in the semiclassical approach, within less than ~1 MeV of difference, both at the maximum attraction and in the surface region. An application of the resulting interaction potential to fusion excitation functions shows clearly that the parameterized universal functions of nuclear proximity potential substitute completely the 'exact' potential in the Skyrme energy density formalism based on the semiclassical ETF method, including also the modifications of interaction barriers at sub-barrier energies in terms of modifying the constants of the universal functions.

Target fragmentation in proton-nucleus and16O-nucleus reactions at 60 and 200 GeV/nucleon

NASA Astrophysics Data System (ADS)

Albrecht, R.; Awes, T. C.; Baktash, C.; Beckmann, P.; Claesson, G.; Berger, F.; Bock, R.; Dragon, L.; Ferguson, R. L.; Franz, A.; Garpman, S.; Glasow, R.; Gustafsson, H. Å.; Gutbrod, H. H.; Kampert, K. H.; Kolb, B. W.; Kristiansson, P.; Lee, I. Y.; Löhner, H.; Lund, I.; Obenshain, F. E.; Oskarsson, A.; Otterlund, I.; Peitzmann, T.; Persson, S.; Plasil, F.; Poskanzer, A. M.; Purschke, M.; Ritter, H. G.; Santo, R.; Schmidt, H. R.; Siemiarczuk, T.; Sorensen, S. P.; Stenlund, E.; Young, G. R.

1988-03-01

Target remnants with Z<3 from proton-nucleus and16O-nucleus reactions at 60 and 200 GeV/nucleon were measured in the angular range from 30° to 160° (-1.7<η<1.3) employing the Plastic Ball detector. The excitation energy of the target spectator matter in central oxygen-induced collisions is found to be high enough to allow for complete disintegration of the target nucleus into fragments with Z<3. The average longitudinal momentum transfer per proton to the target in central collisions is considerably higher in the case of16O-induced reactions (≈300 MeV/c) than in proton-induced reactions (≈130 MeV/c). The baryon rapidity distributions are roughly in agreement with one-fluid hydrodynamical calculations at 60 GeV/nucleon16O+Au but are in disagreement at 200 GeV/nucleon, indicating the higher degree of transparency at the higher bombarding energy. Both, the transverse momenta of target spectators and the entropy produced in the target fragmentation region are compared to those attained in head-on collisions of two heavy nuclei at Bevalac energies. They are found to be comparable or do even exceed the values for the participant matter at beam energies of about 1 2 GeV/nucleon.

Design and construction of a spectrometer facility and experiment for intermediate energy proton scattering on helium. [Wave functions, preliminary experimental techniques

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rolfe, R.M.

1976-12-01

The goal of the research was to investigate proton scattering on nuclei at intermediate energies and in particular to investigate proton scattering on helium. A theoretical investigation of the helium nucleus and the nature of the intermediate energy interaction, design and optimization of an energy-loss spectrometer facility for proton-nucleus scattering, and the unique superfluid helium target and experimental design are discussed.

Scattering and stopping of hadrons in nuclear matter

NASA Technical Reports Server (NTRS)

Strugalski, Z.

1985-01-01

It was observed, in the 180 litre xenon bubble chamber, that when hadrons with kinetic energy higher than the pion production threshold fall on a layer of nuclear matter - on an atomic nucleus in other words - in many cases they can pass through it without causing particles production but they are deflected through some deflection angles; if the energy is lower than a few GeV and the nuclear matter layer is thick enough, the hadrons can be stopped in it. The amount of the deflection at a given incident hadron energy varies with the way the hadron strikes the atomic nucleus; the probability of the occurrence of stopping depends on the incident hadron identity and energy, and on the way the hadron passed through the nucleus, as well.

β-particle energy-summing correction for β-delayed proton emission measurements

DOE PAGES

Meisel, Z.; del Santo, M.; Crawford, H. L.; ...

2016-11-14

One common approach to studying β-delayed proton emission is to measure the energy of the emitted proton and corresponding nuclear recoil in a double-sided silicon-strip detector (DSSD) after implanting the β-delayed proton-emitting (βp) nucleus. However, in order to extract the proton-decay energy, the measured energy must be corrected for the additional energy implanted in the DSSD by the β-particle emitted from the βp nucleus, an effect referred to here as β-summing. Here, we present an approach to determine an accurate correction for β-summing. Our method relies on the determination of the mean implantation depth of the βp nucleus within themore » DSSD by analyzing the shape of the total (proton + recoil + β) decay energy distribution shape. We validate this approach with other mean implantation depth measurement techniques that take advantage of energy deposition within DSSDs upstream and downstream of the implantation DSSD.« less

Nuclear medium effects in muonic neutrino interactions with energies from 0.2 to 1.5 GeV

NASA Astrophysics Data System (ADS)

Vargas, D.; Samana, A. R.; Velasco, F. G.; Hoyos, O. R.; Guzmán, F.; Bernal-Castillo, J. L.; Andrade-II, E.; Perez, R.; Deppman, A.; Barbero, C. A.; Mariano, A. E.

2017-11-01

Nuclear reactions induced by muon neutrinos with energies from 0.2 to 1.5 GeV in the Monte Carlo calculation framework in the intranuclear cascade model are studied. This study was done by comparing the available experimental data and theoretical values of total cross section, and the energy distribution of emitted lepton energy in the reaction muon neutrino nucleus, using the targets 12C, 16O, 27Al, 40Ar, 56Fe, and 208Pb. A phenomenological model of primary neutrino-nucleon interaction gives good agreement between our theoretical inclusive neutrino nucleus cross section and the available experimental data. Some interesting results on the behavior of the cross section as function of 1 p -1 n and higher contributions are also sketched. The previous results on the fraction of fake events in available experiments in 12C were expanded for the set of studied nuclei. With the increase of mass targets, the nuclear effects in the cross sections were observed and the importance of taking into account fake events in the reactions was noted.

Food restriction-induced hyperactivity: addiction or adaptation to famine?

PubMed

Duclos, Martine; Ouerdani, Amel; Mormède, Pierre; Konsman, Jan Pieter

2013-06-01

Increased physical activity is present in 30-80% of anorexia nervosa patients. To explain the paradox of low food intake and excessive exercise in humans and other animals, it has been proposed that increased physical activity along with food restriction activates brain reward circuits and is addictive. Alternatively, the fleeing-famine hypothesis postulates that refusal of known scarce energy-low food sources and hyperactivity facilitate migration towards new habitats that potentially contain new energy-rich foodstuffs. The use of rewarding compounds that differ in energy density, such as the energy-free sweetener saccharin and the energy rich sucrose makes it possible to critically test the reward-addiction and fleeing-famine hypotheses. The aims of the present work were to study if sucrose and/or saccharin could attenuate food restriction-induced hyperactivity, weight loss, increased plasma corticosterone, and activation of brain structures involved in neuroendocrine control, energy balance, physical activity, and reward signaling in rats. Its major findings are that access to sucrose, but not to saccharin, attenuated food restriction-induced running wheel activity, weight loss, rises in plasma corticosterone, and expression of the cellular activation marker c-Fos in the paraventricular and arcuate hypothalamus and in the nucleus accumbens. These findings suggest that the energy-richness and easy availability of sucrose interrupted a fleeing-famine-like hyperactivity response. Since corticosterone mediates food restriction-induced wheel running (Duclos et al., 2009), we propose that the attenuating effect of sucrose consumption on plasma corticosterone plays a role in reduced wheel running and weight loss by lowering activation of the nucleus accumbens and arcuate hypothalamus in these animals. Copyright © 2012 Elsevier Ltd. All rights reserved.

The Changes of Energy Interactions between Nucleus Function and Mitochondria Functions Causing Transmutation of Chronic Inflammation into Cancer Metabolism.

PubMed

Ponizovskiy, Michail R

2016-01-01

Interactions between nucleus and mitochondria functions induce the mechanism of maintenance stability of cellular internal energy according to the first law of thermodynamics in able-bodied cells and changes the mechanisms of maintenance stability of cellular internal energy creating a transition stationary state of ablebodied cells into quasi-stationary pathologic states of acute inflammation transiting then into chronic inflammation and then transmuting into cancer metabolism. The mechanisms' influences of intruding etiologic pathologic agents (microbe, virus, etc.) lead to these changes of energy interactions between nucleus and mitochondria functions causing general acute inflammation, then passing into local chronic inflammation, and reversing into cancer metabolism transmutation. Interactions between biochemical processes and biophysical processes of cellular capacitors' operations create a supplementary mechanism of maintenance stability of cellular internal energy in the norm and in pathology. Discussion of some scientific works eliminates doubts of the authors of these works.

Review of high energy hadron-nucleus data

NASA Astrophysics Data System (ADS)

Lissauer, D.

1987-01-01

In this review we will summarize new data on hardron-nucleus interactions. The possibility that quark-gluon plasma may be created in heavy ion collisions has led to renewed interest in hadron-nucleus collisions. In particular one hopes that understanding the energy loss of hadrons in h-A collissions will allow us to estimate the optimum energy in AA collisions in order to achieve maximum baryon and/or maximum energy density. This will allow us to choose the optimal experimental environment in the search for quark-gluon plasma. This review will thus omit many interesting results from hadron-nucleus collisions, such as the A dependence of lepton pair production, EMC effect and others. We will focus our attention on the following: (i) Estimating the rate of energy loss of the incident hadron as it propagates through the target. (ii) Determining where the enmergy is deposited in central hadron-nucleus collisions. It is clear that there is no direct or unique method of extrapolating our knowledge of h-A collisions to predict what will happen in AA-collisions. The knowledge and understanding of pp and pA collisions is, however, a useful and necessary guide to what one can expect in AA collisions. In this review we will concentrate on three experimental approaches to the study of h-A collisions. In Section 1 we will discuss the present status of pA → p + X inclusive measurements. In Section 2 measurements from visual detectors, in this case results from the 30″ hybrid spectrometer, which allows investigations of global event properties will be presented. In Section 3 data using 2π calorimeters, where one can trigger and measure transverse energy and energy flow over a given rapidity region, will be discussed. The conclusions will be given in Section 4.

Ablation of Sim1 Neurons Causes Obesity through Hyperphagia and Reduced Energy Expenditure

PubMed Central

Xi, Dong; Gandhi, Nilay; Lai, Meizan; Kublaoui, Bassil M.

2012-01-01

Single-minded 1 (Sim1) is a transcription factor necessary for development of the paraventricular nucleus of the hypothalamus (PVH). This nucleus is a critical regulator of appetite, energy expenditure and body weight. Previously we showed that Sim1+/− mice and conditional postnatal Sim1−/− mice exhibit hyperphagia, obesity, increased linear growth and susceptibility to diet-induced obesity, but no decrease in energy expenditure. Bilateral ablation of the PVH causes obesity due to hyperphagia and reduced energy expenditure. It remains unknown whether Sim1 neurons regulate energy expenditure. In this study, Sim1cre mice were bred to homozygous inducible diphtheria toxin receptor (iDTR) mice to generate mice expressing the simian DTR in Sim1 cells. In these mice, Sim1 neuron ablation was performed by intracerebroventricular (ICV) injection of diphtheria toxin. Compared to controls, mice with Sim1 neuron ablation became obese (with increased fat mass) on a chow diet due to increased food intake and reduced energy expenditure. In post-injection mice, we observed a strong inverse correlation between the degree of obesity and hypothalamic Sim1 expression. The reduction in baseline energy expenditure observed in these mice was accompanied by a reduction in activity. This reduction in activity did not fully account for the reduced energy expenditure as these mice exhibited decreased resting energy expenditure, decreased body temperature, decreased brown adipose tissue temperature, and decreased UCP1 expression suggesting an impairment of thermogenesis. In injected mice, hypothalamic gene expression of Sim1, oxytocin (OXT) and thyrotropin releasing hormone (TRH) was reduced by about 50%. These results demonstrate that Sim1 neurons in adult mice regulate both food intake and energy expenditure. Based on the body of work in the field, feeding regulation by Sim1 neurons likely occurs in both the PVH and medial amygdala, in contrast to energy expenditure regulation by Sim1 neurons, which likely is localized to the PVH. PMID:22558467

Ablation of Sim1 neurons causes obesity through hyperphagia and reduced energy expenditure.

PubMed

Xi, Dong; Gandhi, Nilay; Lai, Meizan; Kublaoui, Bassil M

2012-01-01

Single-minded 1 (Sim1) is a transcription factor necessary for development of the paraventricular nucleus of the hypothalamus (PVH). This nucleus is a critical regulator of appetite, energy expenditure and body weight. Previously we showed that Sim1(+/-) mice and conditional postnatal Sim1(-/-) mice exhibit hyperphagia, obesity, increased linear growth and susceptibility to diet-induced obesity, but no decrease in energy expenditure. Bilateral ablation of the PVH causes obesity due to hyperphagia and reduced energy expenditure. It remains unknown whether Sim1 neurons regulate energy expenditure. In this study, Sim1cre mice were bred to homozygous inducible diphtheria toxin receptor (iDTR) mice to generate mice expressing the simian DTR in Sim1 cells. In these mice, Sim1 neuron ablation was performed by intracerebroventricular (ICV) injection of diphtheria toxin. Compared to controls, mice with Sim1 neuron ablation became obese (with increased fat mass) on a chow diet due to increased food intake and reduced energy expenditure. In post-injection mice, we observed a strong inverse correlation between the degree of obesity and hypothalamic Sim1 expression. The reduction in baseline energy expenditure observed in these mice was accompanied by a reduction in activity. This reduction in activity did not fully account for the reduced energy expenditure as these mice exhibited decreased resting energy expenditure, decreased body temperature, decreased brown adipose tissue temperature, and decreased UCP1 expression suggesting an impairment of thermogenesis. In injected mice, hypothalamic gene expression of Sim1, oxytocin (OXT) and thyrotropin releasing hormone (TRH) was reduced by about 50%. These results demonstrate that Sim1 neurons in adult mice regulate both food intake and energy expenditure. Based on the body of work in the field, feeding regulation by Sim1 neurons likely occurs in both the PVH and medial amygdala, in contrast to energy expenditure regulation by Sim1 neurons, which likely is localized to the PVH.

Role of Arcuate Nucleus in the Regulation of Feeding Behavior in the Process of Altitude Acclimatization in Rats.

PubMed

Liu, Xiang-Wen; Yin, Jie; Ma, Qi-Sheng; Qi, Chu-Chu; Mu, Ji-Ying; Zhang, Lang; Gao, Li-Ping; Jing, Yu-Hong

2017-09-01

Liu, Xiang-Wen, Jie Yin, Qi-Sheng Ma, Chu-Chu Qi, Ji-Ying Mu, Lang Zhang, Li-Ping Gao, and Yu-Hong Jing. Role of arcuate nucleus in the regulation of feeding behavior in the process of altitude acclimatization in rats. High Alt Med Biol. 18:234-241, 2017.-Highly efficient energy utilization and metabolic homeostasis maintenance rely on neuromodulation. Altitude exposure is known to stimulate neuroendocrine systems to respond to acute hypoxia and adaptive acclimatization. However, limited data on how the adaptive regulation of the arcuate nucleus performs in the process of altitude acclimatization are available. In the present study, male Sprague Dawley rats were transported to Huashixia, Qinghai (with an altitude of 4400 m) from Xian (with an altitude of 300 m) by air; rats were consistently raised in Xian as control. Food uptake and body weight were measured consecutively after being subjected to high-altitude condition. Contents of plasma leptin and ghrelin were analyzed by the Enzyme Linked Immunosorbent Assay (ELISA) Kits. Brain coronal sections were obtained, and neuropeptide Y (NPY), proopiomelanocotin (POMC), and c-fos immunoreactivity in arcuate nucleus were observed. Arcuate nucleus was isolated from the hypothalamus, and the mRNA of NPY and POMC were measured by quantitative real-time polymerase chain reaction. Our results showed both food consumption and body weight decreased in the high plateau compared with rats raised in the low-altitude condition. Plasma leptin increased at the early stage, and ghrelin decreased at a later stage after reaching the high plateau. The peak of c-fos immunoreactivity in the arcuate nucleus was at day 3 after reaching the high plateau. The expression level of NPY increased, and POMC decreased in the arcuate nucleus at day 7 after reaching the high plateau compared with the plain control group. These results indicate that the arcuate nucleus of hypothalamus performs an important function in regulating feeding behavior during altitude acclimatization. Our study suggested that altitude acclimation is regulated by the hypothalamus that received leptin and ghrelin signals to response by its microcircuit, including NPY- and POMC-neurons in the arcuate nucleus.

Expression of peroxisome proliferator-activated receptor-gamma in key neuronal subsets regulating glucose metabolism and energy homeostasis.

PubMed

Sarruf, David A; Yu, Fang; Nguyen, Hong T; Williams, Diana L; Printz, Richard L; Niswender, Kevin D; Schwartz, Michael W

2009-02-01

In addition to increasing insulin sensitivity and adipogenesis, peroxisome proliferator-activated receptor (PPAR)-gamma agonists cause weight gain and hyperphagia. Given the central role of the brain in the control of energy homeostasis, we sought to determine whether PPARgamma is expressed in key brain areas involved in metabolic regulation. Using immunohistochemistry, PPARgamma distribution and its colocalization with neuron-specific protein markers were investigated in rat and mouse brain sections spanning the hypothalamus, the ventral tegmental area, and the nucleus tractus solitarius. In several brain areas, nuclear PPARgamma immunoreactivity was detected in cells that costained for neuronal nuclei, a neuronal marker. In the hypothalamus, PPARgamma immunoreactivity was observed in a majority of neurons in the arcuate (including both agouti related protein and alpha-MSH containing cells) and ventromedial hypothalamic nuclei and was also present in the hypothalamic paraventricular nucleus, the lateral hypothalamic area, and tyrosine hydroxylase-containing neurons in the ventral tegmental area but was not expressed in the nucleus tractus solitarius. To validate and extend these histochemical findings, we generated mice with neuron-specific PPARgamma deletion using nestin cre-LoxP technology. Compared with littermate controls, neuron-specific PPARgamma knockout mice exhibited dramatic reductions of both hypothalamic PPARgamma mRNA levels and PPARgamma immunoreactivity but showed no differences in food intake or body weight over a 4-wk study period. We conclude that: 1) PPARgamma mRNA and protein are expressed in the hypothalamus, 2) neurons are the predominant source of PPARgamma in the central nervous system, although it is likely expressed by nonneuronal cell types as well, and 3) arcuate nucleus neurons that control energy homeostasis and glucose metabolism are among those in which PPARgamma is expressed.

Estimation of the radiation-induced DNA double-strand breaks number by considering cell cycle and absorbed dose per cell nucleus

PubMed Central

Mori, Ryosuke; Matsuya, Yusuke; Yoshii, Yuji; Date, Hiroyuki

2018-01-01

Abstract DNA double-strand breaks (DSBs) are thought to be the main cause of cell death after irradiation. In this study, we estimated the probability distribution of the number of DSBs per cell nucleus by considering the DNA amount in a cell nucleus (which depends on the cell cycle) and the statistical variation in the energy imparted to the cell nucleus by X-ray irradiation. The probability estimation of DSB induction was made following these procedures: (i) making use of the Chinese Hamster Ovary (CHO)-K1 cell line as the target example, the amounts of DNA per nucleus in the logarithmic and the plateau phases of the growth curve were measured by flow cytometry with propidium iodide (PI) dyeing; (ii) the probability distribution of the DSB number per cell nucleus for each phase after irradiation with 1.0 Gy of 200 kVp X-rays was measured by means of γ-H2AX immunofluorescent staining; (iii) the distribution of the cell-specific energy deposition via secondary electrons produced by the incident X-rays was calculated by WLTrack (in-house Monte Carlo code); (iv) according to a mathematical model for estimating the DSB number per nucleus, we deduced the induction probability density of DSBs based on the measured DNA amount (depending on the cell cycle) and the calculated dose per nucleus. The model exhibited DSB induction probabilities in good agreement with the experimental results for the two phases, suggesting that the DNA amount (depending on the cell cycle) and the statistical variation in the local energy deposition are essential for estimating the DSB induction probability after X-ray exposure. PMID:29800455

Estimation of the radiation-induced DNA double-strand breaks number by considering cell cycle and absorbed dose per cell nucleus.

PubMed

Mori, Ryosuke; Matsuya, Yusuke; Yoshii, Yuji; Date, Hiroyuki

2018-05-01

DNA double-strand breaks (DSBs) are thought to be the main cause of cell death after irradiation. In this study, we estimated the probability distribution of the number of DSBs per cell nucleus by considering the DNA amount in a cell nucleus (which depends on the cell cycle) and the statistical variation in the energy imparted to the cell nucleus by X-ray irradiation. The probability estimation of DSB induction was made following these procedures: (i) making use of the Chinese Hamster Ovary (CHO)-K1 cell line as the target example, the amounts of DNA per nucleus in the logarithmic and the plateau phases of the growth curve were measured by flow cytometry with propidium iodide (PI) dyeing; (ii) the probability distribution of the DSB number per cell nucleus for each phase after irradiation with 1.0 Gy of 200 kVp X-rays was measured by means of γ-H2AX immunofluorescent staining; (iii) the distribution of the cell-specific energy deposition via secondary electrons produced by the incident X-rays was calculated by WLTrack (in-house Monte Carlo code); (iv) according to a mathematical model for estimating the DSB number per nucleus, we deduced the induction probability density of DSBs based on the measured DNA amount (depending on the cell cycle) and the calculated dose per nucleus. The model exhibited DSB induction probabilities in good agreement with the experimental results for the two phases, suggesting that the DNA amount (depending on the cell cycle) and the statistical variation in the local energy deposition are essential for estimating the DSB induction probability after X-ray exposure.

Monte Carlo calculated microdosimetric spread for cell nucleus-sized targets exposed to brachytherapy 125I and 192Ir sources and 60Co cell irradiation.

PubMed

Villegas, Fernanda; Tilly, Nina; Ahnesjö, Anders

2013-09-07

The stochastic nature of ionizing radiation interactions causes a microdosimetric spread in energy depositions for cell or cell nucleus-sized volumes. The magnitude of the spread may be a confounding factor in dose response analysis. The aim of this work is to give values for the microdosimetric spread for a range of doses imparted by (125)I and (192)Ir brachytherapy radionuclides, and for a (60)Co source. An upgraded version of the Monte Carlo code PENELOPE was used to obtain frequency distributions of specific energy for each of these radiation qualities and for four different cell nucleus-sized volumes. The results demonstrate that the magnitude of the microdosimetric spread increases when the target size decreases or when the energy of the radiation quality is reduced. Frequency distributions calculated according to the formalism of Kellerer and Chmelevsky using full convolution of the Monte Carlo calculated single track frequency distributions confirm that at doses exceeding 0.08 Gy for (125)I, 0.1 Gy for (192)Ir, and 0.2 Gy for (60)Co, the resulting distribution can be accurately approximated with a normal distribution. A parameterization of the width of the distribution as a function of dose and target volume of interest is presented as a convenient form for the use in response modelling or similar contexts.

Control of food intake and energy expenditure by Nos1 neurons of the paraventricular hypothalamus.

PubMed

Sutton, Amy K; Pei, Hongjuan; Burnett, Korri H; Myers, Martin G; Rhodes, Christopher J; Olson, David P

2014-11-12

The paraventricular nucleus of the hypothalamus (PVH) contains a heterogeneous cluster of Sim1-expressing cell types that comprise a major autonomic output nucleus and play critical roles in the control of food intake and energy homeostasis. The roles of specific PVH neuronal subtypes in energy balance have yet to be defined, however. The PVH contains nitric oxide synthase-1 (Nos1)-expressing (Nos1(PVH)) neurons of unknown function; these represent a subset of the larger population of Sim1-expressing PVH (Sim1(PVH)) neurons. To determine the role of Nos1(PVH) neurons in energy balance, we used Cre-dependent viral vectors to both map their efferent projections and test their functional output in mice. Here we show that Nos1(PVH) neurons project to hindbrain and spinal cord regions important for food intake and energy expenditure control. Moreover, pharmacogenetic activation of Nos1(PVH) neurons suppresses feeding to a similar extent as Sim1(PVH) neurons, and increases energy expenditure and activity. Furthermore, we found that oxytocin-expressing PVH neurons (OXT(PVH)) are a subset of Nos1(PVH) neurons. OXT(PVH) cells project to preganglionic, sympathetic neurons in the thoracic spinal cord and increase energy expenditure upon activation, though not to the same extent as Nos1(PVH) neurons; their activation fails to alter feeding, however. Thus, Nos1(PVH) neurons promote negative energy balance through changes in feeding and energy expenditure, whereas OXT(PVH) neurons regulate energy expenditure alone, suggesting a crucial role for non-OXT Nos1(PVH) neurons in feeding regulation. Copyright © 2014 the authors 0270-6474/14/3415306-13$15.00/0.

Molecular simulation of flow-enhanced nucleation in n-eicosane melts under steady shear and uniaxial extension.

PubMed

Nicholson, David A; Rutledge, Gregory C

2016-12-28

Non-equilibrium molecular dynamics is used to study crystal nucleation of n-eicosane under planar shear and, for the first time, uniaxial extension. A method of analysis based on the mean first-passage time is applied to the simulation results in order to determine the effect of the applied flow field type and strain rate on the steady-state nucleation rate and a characteristic growth rate, as well as the effects on kinetic parameters associated with nucleation: the free energy barrier, critical nucleus size, and monomer attachment pre-factor. The onset of flow-enhanced nucleation (FEN) occurs at a smaller critical strain rate in extension as compared to shear. For strain rates larger than the critical rate, a rapid increase in the nucleation rate is accompanied by decreases in the free energy barrier and critical nucleus size, as well as an increase in chain extension. These observations accord with a mechanism in which FEN is caused by an increase in the driving force for crystallization due to flow-induced entropy reduction. At high applied strain rates, the free energy barrier, critical nucleus size, and degree of stretching saturate, while the monomer attachment pre-factor and degree of orientational order increase steadily. This trend is indicative of a significant diffusive contribution to the nucleation rate under intense flows that is correlated with the degree of global orientational order in a nucleating system. Both flow fields give similar results for all kinetic quantities with respect to the reduced strain rate, which we define as the ratio of the applied strain rate to the critical rate. The characteristic growth rate increases with increasing strain rate, and shows a correspondence with the nucleation rate that does not depend on the type of flow field applied. Additionally, a structural analysis of the crystalline clusters indicates that the flow field suppresses the compaction and crystalline ordering of clusters, leading to the formation of large articulated clusters under strong flow fields, and compact well-ordered clusters under weak flow fields.

Is {sup 276}U a doubly magic nucleus?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liliani, N., E-mail: netta.liliani@gmail.com; Sulaksono, A.

2016-04-19

We investigate a possible new doubly magic heavy nucleus by using a relativistic mean-field (RMF) model with the addition of a cross interaction term of omega-rho mesons and an electromagnetic exchange term. We propose that {sup 276}U is a doubly magic nucleus. The evidence for {sup 276}U being a doubly magic nucleus is shown through the two-nucleon gaps, the single-particle energies, and the neutron skin thickness of the nucleus. We have also found that the prediction of {sup 276}U as a doubly magic nucleus by the RMF model is not affected by the inclusion of isoscalar-isovector and electromagnetic exchange couplings.

New high resolution measurements of open and hidden charm production in proton-nucleus collisions at √{ s} = 110GeV with LHCb

NASA Astrophysics Data System (ADS)

Maurice, Émilie; LHCb Collaboration

2017-11-01

Open and hidden charm production in nucleus-nucleus collisions is considered as a key probe of Quark Gluon Plasma (QGP) formation. In the search of specific QGP effects, proton-nucleus collisions are used as the reference as they account for the corresponding Cold Nuclear Matter (CNM) effects. The LHCb experiment, thanks to its System for Measuring Overlap with Gas (SMOG) can be operated in a fixed target mode with the LHC beams, at an intermediate center-of-mass energy between nominal SPS and RHIC energies. In 2015, for the first time, reactions of incident LHC proton beams on noble gas targets have been recorded by the LHCb experiment at a center-of-mass energy of 110 GeV and within the center-of-mass rapidity range - 2.77

The atmosphere of a dirty-clathrate cometary nucleus - A two-phase, multifluid model

NASA Astrophysics Data System (ADS)

Marconi, M. L.; Mendis, D. A.

1983-10-01

The dynamical and thermal structure of a dirty-clathrate cometary nucleus' gas atmosphere is presently given a self-consistent, transonic multifluid solution in which, although the heavy neutron and ion species are treated as a single fluid in the collision-dominated region, the photoproduced H is treated separately. The thermal profile of the atmosphere thus obtained is entirely different from those predicted by the earlier, single-fluid models as well as the multifluid models which assumed equipartition of energy between electrons and ions. While the electron gas, like the neutrals and the ions, cools due to expansion, its main mode of energy loss in the inner coma is by way of inelastic collisions with the predominant H2O molecule. The high electron temperature in the outer coma also decreases the efficiency of electron removal by dissociative recombination, thereby increasing electron density throughout the coma.

The selfish brain: competition for energy resources.

PubMed

Fehm, H L; Kern, W; Peters, A

2006-01-01

Although the brain constitutes only 2% of the body mass, its metabolism accounts for 50% of total body glucose utilization. This delicate situation is aggravated by the fact that the brain depends on glucose as energy substrate. Thus, the contour of a major problem becomes evident: how can the brain maintain constant fluxes of large amounts of glucose to itself in the presence of powerful competitors as fat and muscle tissue. Activity of cortical neurons generates an "energy on demand" signal which eventually mediates the uptake of glucose from brain capillaries. Because energy stores in the circulation (equivalent to ca. 5 g glucose) are also limited, a second signal is required termed "energy on request"; this signal is responsible for the activation of allocation processes. The term "allocation" refers to the activation of the "behavior control column" by an input from the hippocampus-amygdala system. As far as eating behavior is concerned the behavior control column consists of the ventral medial hypothalamus (VMH) and periventricular nucleus (PVN). The PVN represents the central nucleus of the brain's stress systems, the hypothalamus-pituitary-adrenal (HPA) axis and the sympathetic nervous system (SNS). Activation of the sympatico-adrenal system inhibits glucose uptake by peripheral tissues by inhibiting insulin release and inducing insulin resistance and increases hepatic glucose production. With an inadequate "energy on request" signal neuroglucopenia would be the consequence. A decrease in brain glucose can activate glucose-sensitive neurons in the lateral hypothalamus (LH) with the release of orexigenic peptides which stimulate food intake. If the energy supply of the brain depends on activation of the LH rather than on increased allocation to the brain, an increase in body weight is evitable. An increase in fat mass will generate feedback signals as leptin and insulin, which activate the arcuate nucleus. Activation of arcuate nucleus in turn will stimulate the activity of the PVN in a way similar to the activation by the hippocampus-amydala system. The activity of PVN is influenced by the hippocampal outflow which in turn is the consequence of a balance of low-affinity and high-affinity glucocorticoid receptors. This set-point can permanently be displaced by extreme stress situations, by starvation, exercise, hormones, drugs or by endocrine-disrupting chemicals. Disorders in the "energy on request" process will influence the allocation of energy and in so doing alter the body mass of the organism. In this "selfish brain theory" the neocortex and the limbic system play a central role in the pathogenesis of diseases, such as anorexia nervosa, obesity and diabetes mellitus type II. From these considerations it appears that the primary disturbance in obesity is a displacement of the hippocampal set-point of the system. The resulting permanent activation of the feedback system must result in a likewise permanent activation of the sympatico-adrenal system, which induces insulin resistance, hypertension and the other components of the metabolic syndrome. Available therapies for treatment of the metabolic syndrome (blockade of alpha- and beta-adrenergic receptors, insulin and insulin secretagogues) interfere with mechanisms, which must be considered compensatory. This explains why these therapies are disappointing in the long run. New therapeutic strategies based on the "selfish brain theory" will be discussed.

Analysis of multi-fragmentation reactions induced by relativistic heavy ions using the statistical multi-fragmentation model

NASA Astrophysics Data System (ADS)

Ogawa, T.; Sato, T.; Hashimoto, S.; Niita, K.

2013-09-01

The fragmentation cross-sections of relativistic energy nucleus-nucleus collisions were analyzed using the statistical multi-fragmentation model (SMM) incorporated with the Monte-Carlo radiation transport simulation code particle and heavy ion transport code system (PHITS). Comparison with the literature data showed that PHITS-SMM reproduces fragmentation cross-sections of heavy nuclei at relativistic energies better than the original PHITS by up to two orders of magnitude. It was also found that SMM does not degrade the neutron production cross-sections in heavy ion collisions or the fragmentation cross-sections of light nuclei, for which SMM has not been benchmarked. Therefore, SMM is a robust model that can supplement conventional nucleus-nucleus reaction models, enabling more accurate prediction of fragmentation cross-sections.

Increased colonic propionate reduces anticipatory reward responses in the human striatum to high-energy foods.

PubMed

Byrne, Claire S; Chambers, Edward S; Alhabeeb, Habeeb; Chhina, Navpreet; Morrison, Douglas J; Preston, Tom; Tedford, Catriona; Fitzpatrick, Julie; Irani, Cherag; Busza, Albert; Garcia-Perez, Isabel; Fountana, Sofia; Holmes, Elaine; Goldstone, Anthony P; Frost, Gary S

2016-07-01

Short-chain fatty acids (SCFAs), metabolites produced through the microbial fermentation of nondigestible dietary components, have key roles in energy homeostasis. Animal research suggests that colon-derived SCFAs modulate feeding behavior via central mechanisms. In humans, increased colonic production of the SCFA propionate acutely reduces energy intake. However, evidence of an effect of colonic propionate on the human brain or reward-based eating behavior is currently unavailable. We investigated the effect of increased colonic propionate production on brain anticipatory reward responses during food picture evaluation. We hypothesized that elevated colonic propionate would reduce both reward responses and ad libitum energy intake via stimulation of anorexigenic gut hormone secretion. In a randomized crossover design, 20 healthy nonobese men completed a functional magnetic resonance imaging (fMRI) food picture evaluation task after consumption of control inulin or inulin-propionate ester, a unique dietary compound that selectively augments colonic propionate production. The blood oxygen level-dependent (BOLD) signal was measured in a priori brain regions involved in reward processing, including the caudate, nucleus accumbens, amygdala, anterior insula, and orbitofrontal cortex (n = 18 had analyzable fMRI data). Increasing colonic propionate production reduced BOLD signal during food picture evaluation in the caudate and nucleus accumbens. In the caudate, the reduction in BOLD signal was driven specifically by a lowering of the response to high-energy food. These central effects were partnered with a decrease in subjective appeal of high-energy food pictures and reduced energy intake during an ad libitum meal. These observations were not related to changes in blood peptide YY (PYY), glucagon-like peptide 1 (GLP-1), glucose, or insulin concentrations. Our results suggest that colonic propionate production may play an important role in attenuating reward-based eating behavior via striatal pathways, independent of changes in plasma PYY and GLP-1. This trial was registered at clinicaltrials.gov as NCT00750438.

Integer ratios of S{sub n}/E{sub n} in {sup 40}Ca+n resonances suggesting two-oscillator excitations in the target nucleus

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ohkubo, Makio

2009-08-15

In s-wave neutron resonances of {sup 40}Ca at E{sub n}{<=}2.5 MeV, S{sub n}/E{sub n} for many levels is found to be of the form 17(n/m) where n, m are small integers. Statistical tests show small probabilities for the observed dispositions of many levels at E{sub n}=(j/k)(1/70)G (j, k; small integers). To meet the requirement of time periodicity of the compound nucleus at resonance, a breathing model is developed, where the excitation energies E{sub x} are written as a sum of inverse integers; E{sub x}=S{sub n}+E{sub n}=G{sigma}(1/k) (k: integer). In {sup 40}Ca+n, the separation energy S{sub n}=8362 keV is written asmore » S{sub n}=(17/70)G=(1/7+1/10)G, where G=34.4 MeV. G is almost equal to the Fermi energy of the nucleus. It is suggested that two oscillators of energy (1/7)G and (1/10)G are excited in {sup 40}Ca by neutron incidence, in which the recurrence energy (1/70)G is resonant with neutrons of energies at (j/k)(1/70)G, forming a simple compound nucleus.« less

Point-by-point model calculation of the prompt neutron multiplicity distribution ν(A) in the incident neutron energy range of multi-chance fission

NASA Astrophysics Data System (ADS)

Tudora, Anabella; Hambsch, Franz-Josef; Tobosaru, Viorel

2017-09-01

Prompt neutron multiplicity distributions ν(A) are required for prompt emission correction of double energy (2E) measurements of fission fragments to determine pre-neutron fragment properties. The lack of experimental ν(A) data especially at incident neutron energies (En) where the multi-chance fission occurs impose the use of ν(A) predicted by models. The Point-by-Point model of prompt emission is able to provide the individual ν(A) of the compound nuclei of the main and secondary nucleus chains undergoing fission at a given En. The total ν(A) is obtained by averaging these individual ν(A) over the probabilities of fission chances (expressed as total and partial fission cross-section ratios). An indirect validation of the total ν(A) results is proposed. At high En, above 70 MeV, the PbP results of individual ν(A) of the first few nuclei of the main and secondary nucleus chains exhibit an almost linear increase. This shape is explained by the damping of shell effects entering the super-fluid expression of the level density parameters. They tend to approach the asymptotic values for most of the fragments. This fact leads to a smooth and almost linear increase of fragment excitation energy with the mass number that is reflected in a smooth and almost linear behaviour of ν(A).

The Confined Hydrogen Atom with a Moving Nucleus

ERIC Educational Resources Information Center

Fernandez, Francisco M.

2010-01-01

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

SU-E-T-667: Radiosensitization Due to Gold Nanoparticles: A Monte Carlo Cellular Dosimetry Investigation of An Expansive Parameter Space

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martinov, M; Thomson, R

2015-06-15

Purpose: To investigate dose enhancement to cellular compartments following gold nanoparticle (GNP) uptake in tissue, varying cell and tissue morphology, intra and extracellular GNP distribution, and source energy using Monte Carlo (MC) simulations. Methods: Models of single and multiple cells are developed for normal and cancerous tissues; cells (outer radii 5–10 µm) are modeled as concentric spheres comprising the nucleus (radii 2.5–7.5 µm) and cytoplasm. GNP distributions modeled include homogeneous distributions throughout the cytoplasm, variable numbers of GNP-containing endosomes within the cytoplasm, or distributed in a spherical shell about the nucleus. Gold concentrations range from 1 to 30 mg/g. Dosemore » to nucleus and to cytoplasm for simulations including GNPs are compared to simulations without GNPs to compute Nuclear and Cytoplasm Dose Enhancement Factors (NDEF, CDEF). Photon source energies are between 20 keV and 1.25 MeV. Results: DEFs are highly sensitive to GNP intracellular distribution; for a 2.5 µm radius nucleus irradiated by a 30 keV source, NDEF varies from 1.2 for a single endosome containing all GNPs to 8.2 for GNPs distributed about the nucleus (7 mg/g). DEFs vary with cell dimensions and source energy: NDEFs vary from 2.5 (90 keV) to 8.2 (30 keV) for a 2.5 µm radius nucleus and from 1.1 (90 keV) to 1.3 (30 keV) for a 7.5 µm radius nucleus, both with GNPs in a spherical shell about the nucleus (7 mg/g). NDEF and CDEF are generally different within a single cell. For multicell models, the presence of gold within intervening tissues between source and target perturbs the fluence reaching cellular targets, resulting in DEF inhomogeneities within a population of irradiated cells. Conclusion: DEFs vary by an order of magnitude for different cell models, GNP distributions, and source energies, demonstrating the importance of detailed modelling for advancing GNP development for radiotherapy. Funding provided by the Natural Sciences and Engineering Council of Canada (NSERC), and the Canada Research Chairs Program (CRC)« less

Production of neutrinos and neutrino-like particles in proton-nucleus interactions. [400 GeV, cross sections

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dishaw, J.P.

1979-03-01

An experimental search was performed to look for the direct production of neutrinos or neutrino-like particles, i.e., neutral particles which interact weakly with hadrons, in proton-nucleus interactions at 400 GeV incident proton energy. Possible sources of such particles include the semi-leptonic decay of new heavy particles such as charm, and the direct production of a light neutral Higgs particle such as the axion. The production of these particles has been inferred in this experiment by energy nonconservation in the collision of a proton with an iron nucleus. The total visible energy of the interaction was measured using a sampling ionizationmore » calorimeter. After correcting for beam intensity effects and cutting the data to eliminate systematic effects in the measurement, the final resolution of the calorimeter was 3.51% and increased with decreasing incident beam energy with a square root dependence on the beam energy. Energy nonconservation in the data is manifest as a non-Gaussian distribution on the low side of the calorimeter measured energy. Model calculations yield the fraction of events expected in this non-Gaussian behavior for the various sources of neutrinos or neutrino-like particles. A maximum likelihood fit to the data with the theoretical fraction of events expected yields the 95% confidence level production cross section upper limit values. The upper limits for general production of neutrino-like particles for various parameterizations of the production cross section are presented. The following specific upper limits have been established: charm particle production < 670 ..mu..barns, supersymmetric particle production carrying an additional quantum number R < 33 ..mu..barns (mass of 1 GeV), 8 ..mu..barns (mass of 3 GeV); axion production < 10/sup -3/ times the ..pi../sup 0/ production cross section. 144 references.« less

Nucleon and deuteron scattering cross sections from 25 MV/Nucleon to 22.5 GeV/Nucleon

NASA Technical Reports Server (NTRS)

Townsend, L. W.; Wilson, J. W.; Bidasaria, H. B.

1983-01-01

Within the context of a double-folding optical potential approximation to the exact nucleus-nucleus multiple-scattering series, eikonal scattering theory is used to generate tables of nucleon and deuteron total and absorption cross sections at kinetic energies between 25 MeV/nucleon and 22.5 GeV/nucleon for use in cosmic-ray transport and shielding studies. Comparisons of predictions for nucleon-nucleus and deuteron-nucleus absorption and total cross sections with experimental data are also made.

The chemical composition of cosmic ray nuclei above 1.3 GeV per nucleus and 23 GeV per nucleus

NASA Technical Reports Server (NTRS)

Badhwar, G. D.; Osborn, R. W.

1974-01-01

Measurements made with a balloon-borne counter telescope are reported. The telescope was flown from Palestine, Tex., during the fall of 1971 for a total of 10 hours under an average residual atmospheric depth of 4.4 g per sq cm. The data analysis indicates that the integral flux ratios above 1.3 GeV per nucleus and 23 GeV per nucleus are consistent with energy independence.

REVIEWS OF TOPICAL PROBLEMS The quark-gluon medium

NASA Astrophysics Data System (ADS)

Dremin, Igor M.; Leonidov, Andrei V.

2011-02-01

The properties of the quark-gluon medium observed in high-energy nucleus-nucleus collisions are discussed. The main experimental facts about these collisions are briefly described and compared with data about proton-proton collisions. Both microscopic and macroscopic approaches to their description are reviewed. The chromodynamics of the quark-gluon medium at high energies is mainly considered. The energy loss of partons moving in this medium is treated. The principal conclusion is that the medium possesses some collective properties which are crucial for understanding the experimental observations.

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

NASA Technical Reports Server (NTRS)

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

1999-01-01

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

Hypothalamic mTOR signaling regulates food intake.

PubMed

Cota, Daniela; Proulx, Karine; Smith, Kathi A Blake; Kozma, Sara C; Thomas, George; Woods, Stephen C; Seeley, Randy J

2006-05-12

The mammalian Target of Rapamycin (mTOR) protein is a serine-threonine kinase that regulates cell-cycle progression and growth by sensing changes in energy status. We demonstrated that mTOR signaling plays a role in the brain mechanisms that respond to nutrient availability, regulating energy balance. In the rat, mTOR signaling is controlled by energy status in specific regions of the hypothalamus and colocalizes with neuropeptide Y and proopiomelanocortin neurons in the arcuate nucleus. Central administration of leucine increases hypothalamic mTOR signaling and decreases food intake and body weight. The hormone leptin increases hypothalamic mTOR activity, and the inhibition of mTOR signaling blunts leptin's anorectic effect. Thus, mTOR is a cellular fuel sensor whose hypothalamic activity is directly tied to the regulation of energy intake.

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

PubMed

Sato, Tatsuhiko; Furusawa, Yoshiya

2012-10-01

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

Increased intake of energy-dense diet and negative energy balance in a mouse model of chronic psychosocial defeat.

PubMed

Coccurello, Roberto; Romano, Adele; Giacovazzo, Giacomo; Tempesta, Bianca; Fiore, Marco; Giudetti, Anna Maria; Marrocco, Ilaria; Altieri, Fabio; Moles, Anna; Gaetani, Silvana

2018-06-01

Chronic exposure to stress may represent a risk factor for developing metabolic and eating disorders, mostly driven by the overconsumption of easily accessible energy-dense palatable food, although the mechanisms involved remain still unclear. In this study, we used an ethologically oriented murine model of chronic stress caused by chronic psychosocial defeat (CPD) to investigate the effects of unrestricted access to a palatable high fat diet (HFD) on food intake, body weight, energy homeostasis, and expression of different brain neuropeptides. Our aim was to shed light on the mechanisms responsible for body weight and body composition changes due to chronic social stress. In our model of subordinate (defeated), mice (CPD) cohabitated in constant sensory contact with dominants, being forced to interact on daily basis, and were offered ad libitum access either to an HFD or to a control diet (CD). Control mice (of the same strain as CPD mice) were housed in pairs and left unstressed in their home cage (UN). In all these mice, we evaluated body weight, different adipose depots, energy metabolism, caloric intake, and neuropeptide expression. CPD mice increased the intake of HFD and reduced body weight in the presence of enhanced lipid oxidation. Resting energy expenditure and interscapular brown adipose tissue (iBAT) were increased in CPD mice, whereas epididymal adipose tissue increased only in HFD-fed unstressed mice. Propiomelanocortin mRNA levels in hypothalamic arcuate nucleus increased only in HFD-fed unstressed mice. Oxytocin mRNA levels in the paraventricular nucleus and neuropeptide Y mRNA levels within the arcuate were increased only in CD-fed CPD mice. In the arcuate, CART was increased in HFD-fed UN mice and in CD-fed CPD mice, while HFD intake suppressed CART increase in defeated animals. In the basolateral amygdala, CART expression was increased only in CPD animals on HFD. CPD appears to uncouple the intake of HFD from energy homeostasis causing higher HFD intake, larger iBAT accumulation, increased energy expenditure and lipid oxidation, and lower body weight. Overall, the present study confirms the notion that the chronic activation of the stress response can be associated with metabolic disorders, altered energy homeostasis, and changes of orexigenic and anorexigenic signaling. These changes might be relevant to better understand the etiology of stress-induced obesity and eating disorders and might represent a valid therapeutic approach for the development of new therapies in this field.

Azimuthal correlation and collective behavior in nucleus-nucleus collisions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mali, P.; Mukhopadhyay, A., E-mail: amitabha-62@rediffmail.com; Sarkar, S.

2015-03-15

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

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

NASA Technical Reports Server (NTRS)

Roychoudhury, R.

1985-01-01

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

Isotopic dependence of fusion enhancement of various heavy ion systems using energy dependent Woods-Saxon potential

NASA Astrophysics Data System (ADS)

Gautam, Manjeet Singh

2015-01-01

In the present work, the fusion of symmetric and asymmetric projectile-target combinations are deeply analyzed within the framework of energy dependent Woods-Saxon potential model (EDWSP model) in conjunction with one dimensional Wong formula and the coupled channel code CCFULL. The neutron transfer channels and the inelastic surface excitations of collision partners are dominating mode of couplings and the coupling of relative motion of colliding nuclei to such relevant internal degrees of freedom produces a significant fusion enhancement at sub-barrier energies. It is quite interesting that the effects of dominant intrinsic degrees of freedom such as multi-phonon vibrational states, neutron transfer channels and proton transfer channels can be simulated by introducing the energy dependence in the nucleus-nucleus potential (EDWSP model). In the EDWSP model calculations, a wide range of diffuseness parameter ranging from a = 0.85 fm to a = 0.97 fm, which is much larger than a value (a = 0.65 fm) extracted from the elastic scattering data, is needed to reproduce sub-barrier fusion data. However, such diffuseness anomaly, which might be an artifact of some dynamical effects, has been resolved by trajectory fluctuation dissipation (TFD) model wherein the resulting nucleus-nucleus potential possesses normal diffuseness parameter.

Energy spectrum of cosmic-ray iron nucleus observed with emulsion chamber

NASA Technical Reports Server (NTRS)

Sato, Y.; Shimada, E.; Ohta, I.; Tasaka, S.; Tanaka, S.; Sugimoto, H.; Taira, K.; Tateyama, N.

1985-01-01

Energy spectrum of cosmic-ray Fe-nucleus has been measured from 4 GeV per nucleon to beyond 100 GeV per nucleon. The data were obtained using emulsion chambers on a balloon from Sanriku, Japan. The energies were estimated by the opening angle method after calibrated using 1.88 GeV per nucleon Fe collisions. The spectrum of Fe is approximately E-2.5 in the range from 10 to 200 GeV per nucleon. This result is in good agreement with those of other experiments.

Regulation of hindbrain Pyy expression by acute food deprivation, prolonged caloric restriction, and weight loss surgery in mice

PubMed Central

Gelegen, C.; Chandarana, K.; Choudhury, A. I.; Al-Qassab, H.; Evans, I. M.; Irvine, E. E.; Hyde, C. B.; Claret, M.; Andreelli, F.; Sloan, S. E.; Leiter, A. B.; Withers, D. J.

2012-01-01

PYY is a gut-derived putative satiety signal released in response to nutrient ingestion and is implicated in the regulation of energy homeostasis. Pyy-expressing neurons have been identified in the hindbrain of river lamprey, rodents, and primates. Despite this high evolutionary conservation, little is known about central PYY neurons. Using in situ hybridization, PYY-Cre;ROSA-EYFP mice, and immunohistochemistry, we identified PYY cell bodies in the gigantocellular reticular nucleus region of the hindbrain. PYY projections were present in the dorsal vagal complex and hypoglossal nucleus. In the hindbrain, Pyy mRNA was present at E9.5, and expression peaked at P2 and then decreased significantly by 70% at adulthood. We found that, in contrast to the circulation, PYY-(1–36) is the predominant isoform in mouse brainstem extracts in the ad libitum-fed state. However, following a 24-h fast, the relative amounts of PYY-(1–36) and PYY-(3–36) isoforms were similar. Interestingly, central Pyy expression showed nutritional regulation and decreased significantly by acute starvation, prolonged caloric restriction, and bariatric surgery (enterogastroanastomosis). Central Pyy expression correlated with body weight loss and circulating leptin and PYY concentrations. Central regulation of energy metabolism is not limited to the hypothalamus but also includes the midbrain and the brainstem. Our findings suggest a role for hindbrain PYY in the regulation of energy homeostasis and provide a starting point for further research on gigantocellular reticular nucleus PYY neurons, which will increase our understanding of the brain stem pathways in the integrated control of appetite and energy metabolism. PMID:22761162

Shielding materials for highly penetrating space radiations

NASA Technical Reports Server (NTRS)

Kiefer, Richard L.; Orwoll, Robert A.

1995-01-01

Interplanetary travel involves the transfer from an Earth orbit to a solar orbit. Once outside the Earth's magnetosphere, the major sources of particulate radiation are solar cosmic rays (SCR's) and galactic cosmic rays (GCR's). Intense fluxes of SCR's come from solar flares and consist primarily of protons with energies up to 1 GeV. The GCR consists of a low flux of nuclei with energies up to 10(exp 10) GeV. About 70 percent of the GCR are protons, but a small amount (0.6 percent) are nuclei with atomic numbers greater than 10. High energy charged particles (HZE) interact with matter by transferring energy to atomic electrons in a Coulomb process and by reacting with an atomic nucleus. Energy transferred in the first process increases with the square of the atomic number, so particles with high atomic numbers would be expected to lose large amounts of energy by this process. Nuclear reactions produced by (HZE) particles produce high-energy secondary particles which in turn lose energy to the material. The HZE nuclei are a major concern for radiation protection of humans during interplanetary missions because of the very high specific ionization of both primary and secondary particles. Computer codes have been developed to calculate the deposition of energy by very energetic charged particles in various materials. Calculations show that there is a significant buildup of secondary particles from nuclear fragmentation and Coulomb dissociation processes. A large portion of these particles are neutrons. Since neutrons carry no charge, they only lose energy by collision or reaction with a nucleus. Neutrons with high energies transfer large amounts of energy by inelastic collisions with nuclei. However, as the neutron energy decreases, elastic collisions become much more effective for energy loss. The lighter the nucleus, the greater the fraction of the neutron's kinetic energy that can be lost in an elastic collision. Thus, hydrogen-containing materials such as polymers are most effective in reducing the energy of neutrons. Once neutrons are reduced to very low energies, the probability for undergoing a reaction with a nucleus (the cross section) becomes very high. The product of such a reaction is often radioactive and can involve the release of a significant amount of energy. Thus, it is important to provide protection from low energy neutrons during a long duration space flight. Among the light elements, lithium and boron each have an isotope with a large thermal neutron capture cross section, Li-6 and B-10. However, B-10 is more abundant in the naturally-occurring element than Li-6, has a thermal neutron capture cross section four times that of Li-6, and produces the stable products, He-4 and Li-7 in the interaction while Li-6 produces radioactive tritium (H-3). Thus, boron is the best light-weight material for thermal neutron absorption in spacecraft. The work on this project was focused in two areas: computer design where existing computer codes were used, and in some cases modified, to calculate the propagation and interactions of high energy charged particles through various media, and materials development where boron was incorporated into high performance materials.

The Neutrino

NASA Astrophysics Data System (ADS)

Reines, Frederick; Cowan, Clyde L.

EACH new discovery of natural science broadens our knowledge and deepens our understanding of the physical universe; but at times these advances raise new and even more fundamental questions than those which they answer. Such was the case with the discovery and investigation of the radioactive process termed `beta decay'. In this process an atomic nucleus spontaneously emits either a negative or positive electron, and in so doing it becomes a different element with the same mass number but with a nuclear charge different from that of the parent element, by one electronic charge. As might be expected, intensive investigation of this interesting alchemy of Nature has shed much light on problems concerning the atomic nucleus. A new question arose at the beginning, however, when it was found that accompanying beta decay there was an unaccountable loss of energy from the decaying nucleus1, and that one could do nothing to the apparatus in which the decay occurred to trap this lost energy2. One possible explanation was that the conservation laws (upon which the entire structure of modern science is built) were not valid when applied to regions of subatomic dimensions. Another novel explanation, but one which would maintain the integrity of the conservation laws, was a proposal by Wolfgang Pauli in 1933 which hypothesized a new and fundamental particle3 to account for the loss of energy from the nucleus. This particle would be emitted by the nucleus simultaneously with the electron, would carry with it no electric charge but, would carry the missing energy and momentum—escaping from the laboratory equipment without detection…

Basic distinctions between cold- and hot-fusion reactions in the synthesis of superheavy elements

NASA Astrophysics Data System (ADS)

Nasirov, A. K.; Muminov, A. I.; Giardina, G.; Mandaglio, G.

2014-07-01

Superheavy elements (SHE) of charge number in the range of Z = 106-112 were synthesized in so-called cold-fusion reactions. The smallness of the excitation energy of compound nuclei is the main advantage of cold-fusion reactions. However, the synthesis of SHEs of charge number in the region of Z ≥ 112 is strongly complicated in cold-fusion reactions by a sharp decrease in the cross section of a compound nucleus formation in the entrance channel because of superiority of quasifission in the competition with complete fusion. Two favorable circumstances contributed to the success of the experiments aimed at the synthesis of the Z = 113-118 elements and performed at the Laboratory of Nuclear Reactions at the Joint Institute for Nuclear Research: large cross sections for the production of a compound nucleus, which are characteristic of hot-fusion reactions, and an increase in the fission barrier for nuclei toward the stability island. The factor that complicates the formation of a compound nucleus in cold-fusion reactions is discussed.

Event-related oscillations (ERO) during an active discrimination task: Effects of lesions of the Nucleus Basalis Magnocellularis

PubMed Central

Sanchez-Alavez, Manuel; Ehlers, Cindy L.

2015-01-01

The cholinergic system in the brain is involved in attentional processes that are engaged for the identification and selection of relevant information in the environment and the formation of new stimulus associations. In the present study we determined the effects of cholinergic lesions of nucleus basalis magnocellularis (NBM) on amplitude and phase characteristics of event related oscillations (EROs) generated in an auditory active discrimination task in rats. Rats were trained to press a lever to begin a series of 1K Hz tones and to release the lever upon hearing a 2 kHz tone. A time-frequency based representation was used to determine ERO energy and phase synchronization (phase lock index, PLI) across trials, recorded within frontal cortical structures. Lesions in NBM produced by an infusion of a-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) resulted in (1) a reduction of the number of correct behavioral responses in the active discrimination task, (2) an increase in ERO energy in the delta frequency bands (3) an increase in theta, alpha and beta ERO energy in the N1, P3a and P3b regions of interest (ROI), and (4) an increase in PLI in the theta frequency band in the N1 ROIs. These studies suggest that the NBM cholinergic system is involved in maintaining the synchronization/phase resetting of oscillations in different frequencies in response to the presentation of the target stimuli in an active discrimination task. PMID:25660307

Fusion cross sections for reactions involving medium and heavy nucleus-nucleus systems

NASA Astrophysics Data System (ADS)

Atta, Debasis; Basu, D. N.

2014-12-01

Existing data on near-barrier fusion excitation functions of medium and heavy nucleus-nucleus systems have been analyzed by using a simple diffused-barrier formula derived assuming the Gaussian shape of the barrier-height distributions. The fusion cross section is obtained by folding the Gaussian barrier distribution with the classical expression for the fusion cross section for a fixed barrier. The energy dependence of the fusion cross section, thus obtained, provides good description to the existing data on near-barrier fusion and capture excitation functions for medium and heavy nucleus-nucleus systems. The theoretical values for the parameters of the barrier distribution are estimated which can be used for fusion or capture cross-section predictions that are especially important for planning experiments for synthesizing new superheavy elements.

Visualization of Radioisotope Detectability Over Time.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huynh, Brady

A radioactive isotope is an atom that has an unstable nucleus. The isotope can undergo radioactive decay, the process in which excessive nuclear energy is emitted from the nucleus in many different forms, such as gamma radiation, alpha particles, or beta particles. The important thing to note is that these emissions act as a signature for the isotope. Each radioisotope has a particular emission spectrum, emitting radiation at different energies and at different rates.

[Magnetic resonance spectroscopy in lenticular nucleus of Bipolar II disorder and its relation with cognitive function].

PubMed

Zhang, Haiyan; Wen, Shenglin; Wang, Jihui; Cheng, Minfeng; Wang, Hong

2015-03-10

To explore the magnetic resonance spectroscopy characteristics of lenticular nucleus in Bipolar II disorder and its relation with cognitive function. Thirty Bipolar II disorder patients in hospital from 2012 September to 2013 April and twenty healthy controls were evaluated with Multi-Voxel 1H-MRS scans on lenticular nucleus to assess the NAA, Cho, Cr and MI. All subjects were assessed for attention using the Stroop Test and executive function by Wisconsin card sorting test. NAA, Cho, Cr in right lenticular nucleus and Cr in left lenticular nucleus were lower than healthy controls (P < 0.05). The patients showed significant cognitive impairment in all aspects of Stroop Test and Wisconsin card sorting test (P < 0.05). NAA in right lenticular nucleus was positively correlated with correct number of Stroop-CW. Neural dysfunction in right lenticular nucleus of Bipolar II disorder may influence attention function. Cellular energy metabolism rate was reduced in bilateral lenticular nucleus.

A Monte Carlo study of macroscopic and microscopic dose descriptors for kilovoltage cellular dosimetry

NASA Astrophysics Data System (ADS)

Oliver, P. A. K.; Thomson, Rowan M.

2017-02-01

This work investigates how doses to cellular targets depend on cell morphology, as well as relations between cellular doses and doses to bulk tissues and water. Multicellular models of five healthy and cancerous soft tissues are developed based on typical values of cell compartment sizes, elemental compositions and number densities found in the literature. Cells are modelled as two concentric spheres with nucleus and cytoplasm compartments. Monte Carlo simulations are used to calculate the absorbed dose to the nucleus and cytoplasm for incident photon energies of 20-370 keV, relevant for brachytherapy, diagnostic radiology, and out-of-field radiation in higher-energy external beam radiotherapy. Simulations involving cell clusters, single cells and single nuclear cavities are carried out for cell radii between 5 and 10~μ m, and nuclear radii between 2 and 9~μ m. Seven nucleus and cytoplasm elemental compositions representative of animal cells are considered. The presence of a cytoplasm, extracellular matrix and surrounding cells can affect the nuclear dose by up to 13 % . Differences in cell and nucleus size can affect dose to the nucleus (cytoplasm) of the central cell in a cluster of 13 cells by up to 13 % (8 % ). Furthermore, the results of this study demonstrate that neither water nor bulk tissue are reliable substitutes for subcellular targets for incident photon energies  <50 keV: nuclear (cytoplasm) doses differ from dose-to-medium by up to 32 % (18 % ), and from dose-to-water by up to 21 % (8 % ). The largest differences between dose descriptors are seen for the lowest incident photon energies; differences are less than 3 % for energies ≥slant 90 keV. The sensitivity of results with regard to the parameters of the microscopic tissue structure model and cell model geometry, and the importance of the nucleus and cytoplasm as targets for radiation-induced cell death emphasize the importance of accurate models for cellular dosimetry studies.

Fluorescent nuclear track detectors for alpha radiation microdosimetry.

PubMed

Kouwenberg, J J M; Wolterbeek, H T; Denkova, A G; Bos, A J J

2018-06-07

While alpha microdosimetry dates back a couple of decades, the effects of localized energy deposition of alpha particles are often still unclear since few comparative studies have been performed. Most modern alpha microdosimetry studies rely for large parts on simulations, which negatively impacts both the simplicity of the calculations and the reliability of the results. A novel microdosimetry method based on the Fluorescent Nuclear Track Detector, a versatile tool that can measure individual alpha particles at sub-micron resolution, yielding accurate energy, fluence and dose rate measurements, was introduced to address these issues. Both the detectors and U87 glioblastoma cell cultures were irradiated using an external Am241 alpha source. The alpha particle tracks measured with a Fluorescent Nuclear Track Detector were used together with high resolution 3D cell geometries images to calculate the nucleus dose distribution in the U87 glioblastoma cells. The experimentally obtained microdosimetry parameters were thereafter applied to simulations of 3D U87 cells cultures (spheroids) with various spatial distributions of isotopes to evaluate the effect of the nucleus dose distribution on the expected cell survival. The new experimental method showed good agreement with the analytically derived nucleus dose distributions. Small differences (< 5%) in the relative effectiveness were found for isotopes in the cytoplasm and on the cell membrane versus external irradiation, while isotopes located in the nucleus or on the nuclear membrane showed a substantial increase in relative effectiveness (33 - 51%). The ease-of-use, good accuracy and use of experimentally derived characteristics of the radiation field make this method superior to conventional simulation-based microdosimetry studies. Considering the uncertainties found in alpha radionuclide carriers in-vivo and in-vitro, together with the large contributions from the relative biological effectiveness and the oxygen enhancement ratio, it is expected that only carriers penetrating or surrounding the cell nucleus will substantially benefit from microdosimetry.

Thermal modeling of cometary nuclei

USGS Publications Warehouse

Weissman, P.R.; Kieffer, H.H.

1981-01-01

A new model of the sublimation of volatile ices from a cometary nucleus has been developed which includes the effects of diurnal heating and cooling, rotation period and pole orientation, and thermal properties of the ice and subsurface layers. The model also includes the contribution from coma opacity, scattering, and thermal emission, where the properties of the coma are derived from the integrated rate of volatile production by the nucleus. The model is applied to the specific case of the 1986 apparition of Halley's comet. It is found that the generation of a cometary dust coma actually increases the total energy reaching the Halley nucleus. This results because of the significantly greater geometrical cross section of the coma as compared with the bare nucleus, and because the coma provides an essentially isotropic source of multiply scattered sunlight and thermal emission over the entire nucleus surface. For Halley, the calculated coma opacity is approximately 0.2 at 1 AU from the Sun, and 1.2 at perihelion (0.587 AU). At 1 AU this has little effect on dayside temperatures (maximum ???200??K) but raises nightside temperatures (minimum ???150??K) by about 40??K. At perihelion the higher opacity results in a nearly isothermal nucleus with only small diurnal and latitudinal temperature variations. The general surface temperature is 205??K with a maximum of 209??K at local noon on the equator. Some possible consequences of the results with respect to the generation of nongravitational forces, observed volatile production rates for comets, and cometary lifetimes against sublimation are discussed. ?? 1981.

Constraining in-medium nucleon-nucleon interactions via nucleus-nucleus reactions

NASA Astrophysics Data System (ADS)

Sammarruca, Francesca; White, Larz

2010-11-01

The nuclear equation of state is a broadly useful tool. Besides being the main input of stellar structure calculations, it allows a direct connection to the physics of nuclei. For instance, an energy functional (such as a mass formula), together with the energy/particle in nuclear matter, can be used to predict nuclear energies and radii [1]. The single-particle properties are also a key point to link infinite nuclear matter and actual nuclei. The parameters of the single-particle potential, in particular the effective mass, enter the calculations of, for instance, in-medium effective cross sections. From the well-known Glauber reaction theory, the total nucleus-nucleus reaction cross section is expressed in terms of the nuclear transparency, which, in turn, depends on the overlap of the nuclear density distributions and the elementary nucleon-nucleon (NN) cross sections. We explore the sensitivity of the reaction calculation to medium modifications of the NN cross sections to estimate the likelihood of constraining the latter through nuclear reactions. Ultimately, we wish to incorporate isospin asymmetry in the reaction model, having in mind connections with rare isotopes. [1] F. Sammarruca, arXiv:1002.00146 [nucl-th]; International Journal of Modern Physics, in press.

Quarkonium-nucleus bound states from lattice QCD

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beane, S.  R.; Chang, E.; Cohen, S.  D.

2015-06-11

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

Soft photon and two hard jets forward production in proton-nucleus collisions

NASA Astrophysics Data System (ADS)

Altinoluk, Tolga; Armesto, Néstor; Kovner, Alex; Lublinsky, Michael; Petreska, Elena

2018-04-01

We calculate the cross section for production of a soft photon and two hard jets in the forward rapidity region in proton-nucleus collisions at high energies. The calculation is performed within the hybrid formalism. The hardness of the final particles is defined with respect to the saturation scale of the nucleus. We consider both the correlation limit of small momentum imbalance and the dilute target limit where the momentum imbalance is of the order of the hardness of the jets. The results depend on the first two transversemomentum-dependent (TMD) gluon distributions of the nucleus.

Relativistic Hydrodynamics for Heavy-Ion Collisions

ERIC Educational Resources Information Center

Ollitrault, Jean-Yves

2008-01-01

Relativistic hydrodynamics is essential to our current understanding of nucleus-nucleus collisions at ultrarelativistic energies (current experiments at the Relativistic Heavy Ion Collider, forthcoming experiments at the CERN Large Hadron Collider). This is an introduction to relativistic hydrodynamics for graduate students. It includes a detailed…

Incorporation of the statistical multi-fragmentation model in PHITS and its application for simulation of fragmentation by heavy ions and protons

NASA Astrophysics Data System (ADS)

Ogawa, Tatsuhiko; Sato, Tatsuhiko; Hashimoto, Shintaro; Niita, Koji

2014-06-01

The fragmentation reactions of relativistic-energy nucleus-nucleus and proton-nucleus collisions were simulated using the Statistical Multi-fragmentation Model (SMM) incorporated with the Particle and Heavy Ion Transport code System (PHITS). The comparisons of calculated cross-sections with literature data showed that PHITS-SMM predicts the fragmentation cross-sections of heavy nuclei up to two orders of magnitude more accurately than PHITS for heavy-ion-induced reactions. For proton-induced reactions, noticeable improvements are observed for interactions of the heavy target with protons at an energy greater than 1 GeV. Therefore, consideration for multi-fragmentation reactions is necessary for the accurate simulation of energetic fragmentation reactions of heavy nuclei.

Nuclear rainbow in elastic scattering of {sup 9}Be nuclei

DOE Office of Scientific and Technical Information (OSTI.GOV)

Glukhov, Yu. A., E-mail: gloukhov@inbox.ru; Ogloblin, A. A.; Artemov, K. P.

2010-01-15

A systematic investigation of the elastic scattering of the {sup 9}Be nucleus, which is among themost loosely bound stable nuclei was performed.Differential cross sections for elastic {sup 9}Be + {sup 16}O scattering were measured at a c.m. energy of 47.5 MeV (beam of 132-MeV {sup 16}O nuclei). Available data at different energy values and data for neighboring nuclei were included in our analysis. As a result, the very fact of rainbow scattering was reliably established for the first time in systems involving {sup 9}Be. In addition, the analysis in question made it possible to identify Airy minima and to determinemore » unambiguously the nucleus-nucleus potential with a high probability.« less

Effect of beta-phenylethylamine on extracellular concentrations of dopamine in the nucleus accumbens and prefrontal cortex.

PubMed

Murata, Mikio; Katagiri, Nobuyuki; Ishida, Kota; Abe, Kenji; Ishikawa, Masago; Utsunomiya, Iku; Hoshi, Keiko; Miyamoto, Ken-ichi; Taguchi, Kyoji

2009-05-07

It is known that psychostimulants stimulate dopamine transmission in the nucleus accumbens. In the present study, we examined the effects of systemically administered beta-phenylethylamine (beta-PEA), a psychomotor-stimulating trace amine, on dopamine concentrations in the nucleus accumbens and prefrontal cortex in freely moving rats, using an in vivo microdialysis technique. Intraperitoneal administration of beta-PEA (12.5 and 25 mg/kg) significantly increased extracellular dopamine levels in the nucleus accumbens shell. The observed increase in the dopamine concentration in nucleus accumbens shell dialysate after intraperitoneal administration of 25 mg/kg beta-PEA was inhibited by pre-treatment with a dopamine uptake inhibitor, GBR12909 (10 mg/kg, i.p.). In contrast, beta-PEA (25 mg/kg, i.p.) did not affect dopamine release in the nucleus accumbens core. Although a high dose of beta-PEA (50 mg/kg) significantly increased dopamine levels in the nucleus accumbens core, the dopamine increasing effect of beta-PEA was more potent in the nucleus accumbens shell. Systemic administration of 12.5 and 25 mg/kg beta-PEA also increased extracellular dopamine levels in the prefrontal cortex of rats. However, systemic 25 mg/kg beta-PEA-induced increases in extracellular dopamine levels were not blocked by GBR12909 within the prefrontal cortex. These results suggest that beta-PEA has a greater effect in the shell than in the core and low-dose beta-PEA stimulates dopamine release in the nucleus accumbens shell through uptake by a dopamine transporter. Similarly, beta-PEA increased extracellular dopamine levels in the prefrontal cortex. Thus, beta-PEA may increase extracellular dopamine concentrations in the mesocorticolimbic pathway.

Proton-proton correlations at small relative momentum in neon-nucleus collisions at E/A=400 and 800 MeV

NASA Technical Reports Server (NTRS)

Dupieux, P.; Alard, J. P.; Augerat, J.; Babinet, R.; Bastid, N.; Brochard, F.; Charmensat, P.; De Marco, N.; Fanet, H.; Fodor, Z.;

Intermediate-energy nuclear chemistry workshop

DOE Office of Scientific and Technical Information (OSTI.GOV)

Butler, G.W.; Giesler, G.C.; Liu, L.C.

1981-05-01

This report contains the proceedings of the LAMPF Intermediate-Energy Nuclear Chemistry Workshop held in Los Alamos, New Mexico, June 23-27, 1980. The first two days of the Workshop were devoted to invited review talks highlighting current experimental and theoretical research activities in intermediate-energy nuclear chemistry and physics. Working panels representing major topic areas carried out indepth appraisals of present research and formulated recommendations for future research directions. The major topic areas were Pion-Nucleus Reactions, Nucleon-Nucleus Reactions and Nuclei Far from Stability, Mesonic Atoms, Exotic Interactions, New Theoretical Approaches, and New Experimental Techniques and New Nuclear Chemistry Facilities.

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

NASA Technical Reports Server (NTRS)

Norbury, John W.

1992-01-01

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

Charge dependence and electric quadrupole effects on single-nucleon removal in relativistic and intermediate energy nuclear collisions

NASA Technical Reports Server (NTRS)

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

1990-01-01

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

Using experimental data to test an n -body dynamical model coupled with an energy-based clusterization algorithm at low incident energies

NASA Astrophysics Data System (ADS)

Kumar, Rohit; Puri, Rajeev K.

2018-03-01

Employing the quantum molecular dynamics (QMD) approach for nucleus-nucleus collisions, we test the predictive power of the energy-based clusterization algorithm, i.e., the simulating annealing clusterization algorithm (SACA), to describe the experimental data of charge distribution and various event-by-event correlations among fragments. The calculations are constrained into the Fermi-energy domain and/or mildly excited nuclear matter. Our detailed study spans over different system masses, and system-mass asymmetries of colliding partners show the importance of the energy-based clusterization algorithm for understanding multifragmentation. The present calculations are also compared with the other available calculations, which use one-body models, statistical models, and/or hybrid models.

Particle production at RHIC and LHC energies

NASA Astrophysics Data System (ADS)

Tawfik, A.; Gamal, E.; Shalaby, A. G.

2015-07-01

The production of pion, kaon and proton was measured in Pb-Pb collisions at nucleus-nucleus center-of-mass energy sNN = 2.76TeV by the ALICE experiment at Large Hadron Collider (LHC). The particle ratios of these species compared to the RHIC measurements are confronted to the hadron resonance gas (HRG) model and to simulations based on the event generators PYTHIA 6.4.21 and HIJING 1.36. It is found that the homogeneous particle-antiparticle ratios (same species) are fully reproducible by means of HRG and partly by PYTHIA 6.4.21 and HIJING 1.36. The mixed kaon-pion and proton-pion ratios measured at RHIC and LHC energies seem to be reproducible by the HRG model. On the other hand, the strange abundances are underestimated in both event generators. This might be originated to strangeness suppression in the event generators and/or possible strangeness enhancement in the experimental data. It is apparent that the values of kaon-pion ratios are not sensitive to the huge increase of sNN from 200 (RHIC) to 2760 GeV (LHC). We conclude that the ratios of produced particle at LHC seem not depending on the system size.

Measurement of Ratios of ν μ Charged-Current Cross Sections on C, Fe, and Pb to CH at Neutrino Energies 2–20 GeV

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tice, B. G.; Datta, M.; Mousseau, J.

2014-06-01

We present measurements of ν μ charged-current cross section ratios on carbon, iron, and lead relative to a scintillator (CH) using the fine-grained MINERvA detector exposed to the NuMI neutrino beam at Fermilab. The measurements utilize events of energies 2 < E ν < 20 GeV , with ( E ν more » ) = 8 GeV , which have a reconstructed μ - scattering angle less than 17° to extract ratios of inclusive total cross sections as a function of neutrino energy E ν and flux-integrated differential cross sections with respect to the Bjorken scaling variable x . These results provide the first high-statistics direct measurements of nuclear effects in neutrino scattering using different targets in the same neutrino beam. Measured cross section ratios exhibit a relative depletion at low x and enhancement at large x . Both become more pronounced as the nucleon number of the target nucleus increases. The data are not reproduced by GENIE, a conventional neutrino-nucleus scattering simulation, or by the alternative models for the nuclear dependence of inelastic scattering that are considered.« less

Frequency sensitive mechanism in low-intensity ultrasound enhanced bioeffects

PubMed Central

Chama, Abdoulkadri; Subramanian, Anuradha; Viljoen, Hendrik J.

2017-01-01

This study presents two novel theoretical models to elucidate frequency sensitive nuclear mechanisms in low-intensity ultrasound enhanced bioeffects. In contrast to the typical 1.5 MHz pulsed ultrasound regime, our group previously experimentally confirmed that ultrasound stimulation of anchored chondrocytes at resonant frequency maximized gene expression of load inducible genes which are regulatory markers for cellular response to external stimuli. However, ERK phosphorylation displayed no frequency dependency, suggesting that the biochemical mechanisms involved in enhanced gene expression is downstream of ERK phosphorylation. To elucidate such underlying mechanisms, this study presents a theoretical model of an anchored cell, representing an in vitro chondrocyte, in an ultrasound field. The model results showed that the mechanical energy storage is maximized at the chondrocyte’s resonant frequency and the energy density in the nucleus is almost twice as high as in the cytoplasm. Next, a mechanochemical model was developed to link the mechanical stimulation of ultrasound and the increased mechanical energy density in the nucleus to the downstream targets of the ERK pathway. This study showed for the first time that ultrasound stimulation induces frequency dependent gene expression as a result of altered rates of transcription factors binding to chromatin. PMID:28763448

Hidden asymmetry and forward-backward correlations

NASA Astrophysics Data System (ADS)

Bialas, A.; Zalewski, K.

2010-09-01

A model-independent method of studying the forward-backward correlations in symmetric high-energy processes is developed. The method allows a systematic study of the properties of various particle sources and allows one to uncover asymmetric structures hidden in symmetric hadron-hadron and nucleus-nucleus inelastic reactions.

Einstein observations of the X-ray structure of Centaurus A - Evidence for the radio-lobe energy source

NASA Technical Reports Server (NTRS)

Schreier, E. J.; Feigelson, E.; Delvaille, J.; Giacconi, R.; Grindlay, J.; Schwartz, D. A.; Fabian, A. C.

1979-01-01

The X-ray source at the center of the radio galaxy Centaurus A has been resolved into the following components with the imaging detectors on board the Einstein X-ray Observatory: (1) a point source coincident with the infrared nucleus; (2) diffuse X-ray emission coinciding with the inner radio lobes; (3) a 4-arcmin extended region of emission about the nucleus; and (4) an X-ray jet between the nucleus and the NE inner radio lobe. The 2 x 10 to the 39th ergs/s detected from the radio lobes probably arises from inverse Compton scattering of the microwave background. The average magnetic field in the SW lobe is determined to be not less than 4 microgauss. The extended region may be due to emission by a cloud of hot gas, cosmic-ray scattering, or stellar sources. The jet provides strong evidence for the continuous resupply of energy to the lobes from the nucleus.

LGR4 and Its Ligands, R-Spondin 1 and R-Spondin 3, Regulate Food Intake in the Hypothalamus of Male Rats

PubMed Central

Li, Ji-Yao; Chai, Biaoxin; Zhang, Weizhen; Fritze, Danielle M.; Zhang, Chao

2014-01-01

The hypothalamus plays a key role in the regulation of feeding behavior. Several hypothalamic nuclei, including the arcuate nucleus (ARC), paraventricular nucleus, and ventromedial nucleus of the hypothalamus (VMH), are involved in energy homeostasis. Analysis of microarray data derived from ARC revealed that leucine-rich repeat-containing G protein-coupled receptor 4 (LGR4) is highly expressed. LGR4, LGR5, and LGR6 form a subfamily of closely related receptors. Recently, R-spondin (Rspo) family proteins were identified as ligands of the LGR4 subfamily. In the present study, we investigated the distribution and function of LGR4–LGR6 and Rspos (1–4) in the brain of male rat. In situ hybridization showed that LGR4 is expressed in the ARC, VMH, and median eminence of the hypothalamus. LGR4 colocalizes with neuropeptide Y, proopiomelanocortin, and brain-derived neurotrophic factor neurons. LGR5 is not detectable with in situ hybridization; LGR6 is only expressed in the epithelial lining of the lower portion of the third ventricle and median eminence. Rspo1 is expressed in the VMH and down-regulated with fasting. Rspo3 is expressed in the paraventricular nucleus and also down-regulated with fasting. Rspos 1 and 3 colocalize with the neuronal marker HuD, indicating that they are expressed by neurons. Injection of Rspo1 or Rspo3 into the third brain ventricle inhibited food intake. Rspo1 decreased neuropeptide Y and increased proopiomelanocortin expression in the ARC. Rspo1 and Rspo3 mRNA is up-regulated by insulin. These data indicate that Rspo1 and Rspo3 and their receptor LGR4 form novel circuits in the brain to regulate energy homeostasis. PMID:24280058

LGR4 and its ligands, R-spondin 1 and R-spondin 3, regulate food intake in the hypothalamus of male rats.

PubMed

Li, Ji-Yao; Chai, Biaoxin; Zhang, Weizhen; Fritze, Danielle M; Zhang, Chao; Mulholland, Michael W

2014-02-01

The hypothalamus plays a key role in the regulation of feeding behavior. Several hypothalamic nuclei, including the arcuate nucleus (ARC), paraventricular nucleus, and ventromedial nucleus of the hypothalamus (VMH), are involved in energy homeostasis. Analysis of microarray data derived from ARC revealed that leucine-rich repeat-containing G protein-coupled receptor 4 (LGR4) is highly expressed. LGR4, LGR5, and LGR6 form a subfamily of closely related receptors. Recently, R-spondin (Rspo) family proteins were identified as ligands of the LGR4 subfamily. In the present study, we investigated the distribution and function of LGR4-LGR6 and Rspos (1-4) in the brain of male rat. In situ hybridization showed that LGR4 is expressed in the ARC, VMH, and median eminence of the hypothalamus. LGR4 colocalizes with neuropeptide Y, proopiomelanocortin, and brain-derived neurotrophic factor neurons. LGR5 is not detectable with in situ hybridization; LGR6 is only expressed in the epithelial lining of the lower portion of the third ventricle and median eminence. Rspo1 is expressed in the VMH and down-regulated with fasting. Rspo3 is expressed in the paraventricular nucleus and also down-regulated with fasting. Rspos 1 and 3 colocalize with the neuronal marker HuD, indicating that they are expressed by neurons. Injection of Rspo1 or Rspo3 into the third brain ventricle inhibited food intake. Rspo1 decreased neuropeptide Y and increased proopiomelanocortin expression in the ARC. Rspo1 and Rspo3 mRNA is up-regulated by insulin. These data indicate that Rspo1 and Rspo3 and their receptor LGR4 form novel circuits in the brain to regulate energy homeostasis.

An Investigation of Age-Related Iron Deposition Using Susceptibility Weighted Imaging

PubMed Central

Wang, Dan; Li, Wen-Bin; Wei, Xiao-Er; Li, Yue-Hua; Dai, Yong-Ming

2012-01-01

Aim To quantify age-dependent iron deposition changes in healthy subjects using Susceptibility Weighted Imaging (SWI). Materials and Methods In total, 143 healthy volunteers were enrolled. All underwent conventional MR and SWI sequences. Subjects were divided into eight groups according to age. Using phase images to quantify iron deposition in the head of the caudate nucleus and the lenticular nucleus, the angle radian value was calculated and compared between groups. ANOVA/Pearson correlation coefficient linear regression analysis and polynomial fitting were performed to analyze the relationship between iron deposition in the head of the caudate nucleus and lenticular nucleus with age. Results Iron deposition in the lenticular nucleus increased in individuals aged up to 40 years, but did not change in those aged over 40 years once a peak had been reached. In the head of the caudate nucleus, iron deposition peaked at 60 years (p<0.05). The correlation coefficients for iron deposition in the L-head of the caudate nucleus, R-head of the caudate nucleus, L-lenticular nucleus and R-lenticular nucleus with age were 0.67691, 0.48585, 0.5228 and 0.5228 (p<0.001, respectively). Linear regression analyses showed a significant correlation between iron deposition levels in with age groups. Conclusions Iron deposition in the lenticular nucleus was found to increase with age, reaching a plateau at 40 years. Iron deposition in the head of the caudate nucleus also increased with age, reaching a plateau at 60 years. PMID:23226360

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

PubMed

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

2015-01-01

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

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

PubMed Central

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

2015-01-01

Nuclear motions like rotation, translation and deformation suggest that the nucleus is acted upon by mechanical forces. Molecular linkages with the cytoskeleton are thought to transfer forces to the nuclear surface. We developed an approach to apply reproducible, known mechanical forces to the nucleus in spread adherent cells and quantified the elastic response of the mechanically integrated nucleus-cell. The method is sensitive to molecular perturbations and revealed new insight into the function of the LINC complex. While these experiments revealed elastic behaviors, turnover of the cytoskeleton by assembly/disassembly and binding/unbinding of linkages are expected to dissipate any stored mechanical energy in the nucleus or the cytoskeleton. Experiments investigating nuclear forces over longer time scales demonstrated the mechanical principle that expansive/compressive stresses on the nuclear surface arise from the movement of the cell boundaries to shape and position the nucleus. Such forces can shape the nucleus to conform to cell shapes during cell movements with or without myosin activity. PMID:26338356

Breakup and fusion cross sections of the 6Li nucleus with targets of mass A = 58, 144 and 208

NASA Astrophysics Data System (ADS)

Mukeru, B.; Rampho, G. J.; Lekala, M. L.

2018-04-01

We use the continuum discretized coupled channels method to investigate the effects of continuum-continuum coupling on the breakup and fusion cross sections of the weakly bound 6Li nucleus with the 58Ni, 144Sm and 208Pb nuclear targets. The cross sections were analyzed at incident energies E cm below, close to and above the Coulomb barrier V B. We found that for the medium and heavy targets, the breakup cross sections are enhanced at energies below the Coulomb barrier (E cm/V B ≤ 0.8) owing to these couplings. For the lighter target, relatively small enhancement of the breakup cross sections appear at energies well below the barrier (E cm/V B ≤ 0.6). At energies E cm/V B > 0.8 for medium and heavy targets, and E cm/V B > 0.6 for the light target, the continuum-continuum couplings substantially suppress the breakup cross sections. On the other hand, the fusion cross sections are enhanced at energies E cm/V B < 1.4, E cm/V B < 1.2 and E cm/V B < 0.8 for the light, medium and heavy target, respectively. The enhancement decreases as the target mass increases. Above the indicated respective energies, these couplings suppress the fusion cross sections. We also compared the breakup and fusion cross sections, and found that below the barrier, the breakup cross sections are more dominant regardless of whether continuum-continuum couplings are included.

Multiplicities of secondaries in nuclear interactions, induced by 20Ne, 40Ar and 56Fe nuclei at 0.1-0.5 GeV/nucleon

NASA Technical Reports Server (NTRS)

Dudkin, V. E.; Kovalev, E. E.; Nefedov, N. A.; Antonchik, V. A.; Bogdanov, S. D.; Kosmach, V. F.; Hassan, J.; Benton, E. V.; Crawford, H. J.

1994-01-01

Multiplicities of various species of charged secondaries produced in inelastic interactions of 20Ne, 40Ar and 56Fe nuclei with emulsion nuclei at 0.1-0.5 GeV/nucleon have been measured. The data obtained are compared with the results for interactions of higher energy nuclei with emulsion nuclei. The dependences of the nucleus-nucleus interaction parameters on masses and energies of colliding nuclei are examined.

The amalgamation stage of fusion reactions

NASA Astrophysics Data System (ADS)

Mouze, Genevieve

2005-04-01

There is no need of a repulsive potential in the amalgamation stage for explaining the small fusion cross sections. The repulsive potential proposed by A. Adamian et al.(1) can advantageously be replaced by the affinity of the reaction of re-dissociation of the compound nucleus into its entrance-channel configuration. This reaction, which occurs after the penetration of the Coulomb barrier, is an equilibrium between dual and compact form of the compound nucleus, and the energy Q released in the dissociation is equal to the energy required for amalgamating. The total energy of the confined system being equal to the height B of the Coulomb barrier, the intrinsic excitation energy of the compact nucleus is equal to (B - Q). In the reaction 82Se+ 138Ba (2), the dissociation of 220Th releases 180.524 MeV, and B= 196.08 MeV. With an intrinsic excitation energy of 15.56 MeV, the confined compact 220Th has enough energy for emitting two neutrons ( S(2n) = 13.85 MeV). Thus the favored xn channel of fusion reactions can be precisely predicted. This new, mass-data-based model of fusion is completely parameter-free. 1 G.G. Adamian et al., PRC 69 (2004) 044601. 2 K. Satou et al. PRC C 65(2002) 054602.

Thermodynamic and kinetic considerations of nucleation and stabilization of acoustic cavitation bubbles in water.

PubMed

Bapat, Pratap S; Pandit, Aniruddha B

2008-01-01

Qualitative explanation for a homogeneous nucleation of acoustic cavitation bubbles in the incompressible liquid water with simple phenomenological approach has been provided via the concept of the desorbtion of the dissolved gas and the vaporization of local liquid molecules. The liquid medium has been viewed as an ensemble of lattice structures. Validity of the lattice structure approach against the Brownian motion of molecules in the liquid state has been discussed. Criterion based on probability for nucleus formation has been defined for the vaporization of local liquid molecules. Energy need for the enthalpy of vaporization has been considered as an energy criterion for the formation of a vaporous nucleus. Sound energy, thermal energy of the liquid bulk (Joule-Thomson effect) and free energy of activation, which is associated with water molecules in the liquid state (Brownian motion) as per the modified Eyring's kinetic theory of liquid are considered as possible sources for the enthalpy of vaporization of water molecules forming a single unit lattice. The classical nucleation theory has then been considered for expressing further growth of the vaporous nucleus against the surface energy barrier. Effect of liquid property (temperature), and effect of an acoustic parameter (frequency) on an acoustic cavitation threshold pressure have been discussed. Kinetics of nucleation has been considered.

Zinc release in the lateral nucleus of the amygdala by stimulation of the entorhinal cortex.

PubMed

Takeda, Atsushi; Imano, Sachie; Itoh, Hiromasa; Oku, Naoto

2006-11-06

Zinc release in the lateral nucleus of the amygdala was examined using rat brain slices. The lateral and basolateral nuclei in the amygdala were evidently stained by Timm's sulfide-silver staining method. When the amygdala including both the nuclei was stimulated with 100 mM KCl by means of in vivo microdialysis, extracellular zinc concentration was increased significantly. Zinc release in the lateral nucleus of the amygdala innervated by the entorhinal cortex was next examined in brain slices double-stained with zinc and calcium indicators. Extracellular zinc signal (ZnAF-2) in the lateral nucleus was increased with intracellular calcium signal (calcium orange) during delivery of tetanic stimuli to the entorhinal cortex. Both the increases were completely inhibited by addition of 1 micro M tetrodotoxin, a sodium channel blocker. Furthermore, calcium signal in the lateral nucleus during delivery of tetanic stimuli to the entorhinal cortex was increased in the presence of 10 micro M CNQX, an AMPA/KA receptor antagonist, and this increase was facilitated by addition of 1 mM CaEDTA, a membrane-impermeable zinc chelator. The present study suggested that zinc is released in the lateral nucleus of the amygdala by depolarization of the entorhinal neurons. In the lateral nucleus, zinc released may suppress the increase in presynaptic calcium signal.

The ghrelin receptor agonist HM01 mimics the neuronal effects of ghrelin in the arcuate nucleus and attenuates anorexia-cachexia syndrome in tumor-bearing rats.

PubMed

Borner, Tito; Loi, Laura; Pietra, Claudio; Giuliano, Claudio; Lutz, Thomas A; Riediger, Thomas

2016-07-01

The gastric hormone ghrelin positively affects energy balance by increasing food intake and reducing energy expenditure. Ghrelin mimetics are a possible treatment against cancer anorexia-cachexia syndrome (CACS). This study aimed to characterize the action of the nonpeptidergic ghrelin receptor agonist HM01 on neuronal function, energy homeostasis and muscle mass in healthy rats and to evaluate its possible usefulness for the treatment of CACS in a rat tumor model. Using extracellular single-unit recordings, we tested whether HM01 mimics the effects of ghrelin on neuronal activity in the arcuate nucleus (Arc). Furthermore, we assessed the effect of chronic HM01 treatment on food intake (FI), body weight (BW), lean and fat volumes, and muscle mass in healthy rats. Using a hepatoma model, we investigated the possible beneficial effects of HM01 on tumor-induced anorexia, BW loss, muscle wasting, and metabolic rate. HM01 (10(-7)-10(-6) M) mimicked the effect of ghrelin (10(-8) M) by increasing the firing rate in 76% of Arc neurons. HM01 delivered chronically for 12 days via osmotic minipumps (50 μg/h) increased FI in healthy rats by 24%, paralleled by increased BW, higher fat and lean volumes, and higher muscle mass. Tumor-bearing rats treated with HM01 had 30% higher FI than tumor-bearing controls and were protected against BW loss. HM01 treatment resulted in higher muscle mass and fat mass. Moreover, tumor-bearing rats reduced their metabolic rate following HM01 treatment. Our studies substantiate the possible therapeutic usefulness of ghrelin receptor agonists like HM01 for the treatment of CACS and possibly other forms of disease-related anorexia and cachexia. Copyright © 2016 the American Physiological Society.

Proton-hole and core-excited states in the semi-magic nucleus 131In82

DOE Office of Scientific and Technical Information (OSTI.GOV)

Taprogge, J.; Jungclaus, A.; Grawe, H.

2016-11-01

The decay of the N = 83 nucleus Cd-131 has been studied at the RIBF facility at the RIKEN Nishina Center. The main purpose of the study was to identify the position of the and proton-hole states and the energies of core-excited configurations in the semi-magic nucleus In-131. From the radiation emitted following the decay, a level scheme of In-131 was established and the feeding to each excited state determined. Similarities between the single-particle transitions observed in the decays of the N = 83 isotones In-132 and Cd-131 are discussed. Finally the excitation energies of several core-excited configurations in In-131more » are compared to QRPA and shell-model calculations.« less

Heavy nucleus collisions between 20 and 60 GeV/nucleon

NASA Technical Reports Server (NTRS)

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

1985-01-01

Interest in studying relativistic nucleus-nucleus interations arises from the fact that they offer an opportunity to probe nuclear matter at high density and temperature. It is expected that under such extreme conditions a transition from hadronic matter into quark-gluon plasma occurs and that in the interactions of highly relativistic nuclei such conditions are created. Cosmic rays remain a unique source of high energy heavy nuclei. The Japanese-American Cooperative Emulsion Experiment (JACEE-3) was designed to study the collisions of heavy cosmic ray nuclei with different nuclear targets at energies beyond 20 GeV/nucleon. JACEE-3 experiment was carried out using a combined electronic counters and an emulsion chamber detector, which was exposed to the cosmic rays on a balloon at an altitude of 5 g/sq cm.

Composition and distribution of elements and ultrastructural topography of a human cardiac calculus.

PubMed

Cheng, Ching-Li; Chang, Hsiao-Huang; Huang, Pei-Jung; Chu, Yu-Ting; Lin, Shan-Yang

2013-04-01

Trace elements (TEs) may contribute to the formation of calculi or stones or be involved in the aetiopathogenesis of stone diseases. The compositions and spatial distribution of elements from the inner nucleus to outer crust of the cardiac calculus were investigated by energy-dispersive X-ray fluorescence (EDXRF) spectrometer. The surface topograph, distribution map of elements, elemental and chemical compositions were also determined by environmental scanning electron microscope (ESEM)-energy-dispersive X-ray (EDX) analysis. Twenty-five elements were identifiable from 18 positions on the cardiac calculus by EDXRF spectrometer, in which the highest concentrations of toxic TEs (Ni, Pt, Hg, Sn, Pb, W, Au, Al, Si) and higher levels of essential TEs (Ca, Sr, Cr, P) were detected. A moderate positive Pearson's correlation between TEs concentrations of Mg, Ca or P and location differences from centre to periphery in the cardiac calculus was observed. A positive correlation was also found for Ca/Zn and Ca/Cu, indicating the gradual increase of calcium concentration from inner nucleus to outer crust of cardiac calculus. The drop-like nodules/crystals on the surface of petrous part of cardiac calculus were observed from ESEM analysis. ESEM-EDX analysis determined the calculus to be predominantly composed of calcium hydroxyapatite and cholesterol, as indicated by the petrous surface and drop-like nodules/crystals, respectively. This composition was confirmed using a portable Raman analyser. The spatial distribution analysis indicated a gradual increase in Mg, P and Ca concentrations from the inner nucleus to the outer crust of the cardiac calculus. The major chemical compositions of calcium hydroxyapatite and cholesterol were detected on this cardiac calculus.

Workshop on Cosmic Ray and High Energy Gamma Ray Experiments for the Space Station Era, Louisiana State University, Baton Rouge, October 17-20, 1984, Proceedings

NASA Technical Reports Server (NTRS)

Jones, W. V. (Editor); Wefel, J. P. (Editor)

1985-01-01

The potential of the Space Station as a platform for cosmic-ray and high-energy gamma-ray astronomy is discussed in reviews, reports, and specific proposals. Topics examined include antiparticles and electrons, science facilities and new technology, high-energy nuclear interactions, nuclear composition and energy spectra, Space Shuttle experiments, Space Station facilities and detectors, high-energy gamma rays, and gamma-ray facilities and techniques. Consideration is given to universal-baryon-symmetry testing on the scale of galactic clusters, particle studies in a high-inclination orbit, balloon-borne emulsion-chamber results on ultrarelativistic nucleus-nucleus interactions, ionization states of low-energy cosmic rays, a large gamma-ray telescope for point-source studies above 1 GeV, and the possible existence of stable quark matter.

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

USDA-ARS?s Scientific Manuscript database

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

Statistical Analysis For Nucleus/Nucleus Collisions

NASA Technical Reports Server (NTRS)

Mcguire, Stephen C.

1989-01-01

Report describes use of several statistical techniques to charactertize angular distributions of secondary particles emitted in collisions of atomic nuclei in energy range of 24 to 61 GeV per nucleon. Purpose of statistical analysis to determine correlations between intensities of emitted particles and angles comfirming existence of quark/gluon plasma.

Comparison of the ablation ability of nucleus pulposus after 1,064 nm Nd:YAG laser and 980 nm diode laser radiation.

PubMed

Yin, Jian; Han, Zhengfeng; Guo, Baofeng; Guo, Han; Zhang, Tongtong; Zeng, Yanjun; Ren, Longxi

2015-07-01

To compare the ablation ability of nucleus pulposus after 1,064 nm Nd:YAG laser and 980 nm diode laser radiation. Goat spine specimen (GSS) was radiated using Nd:YAG laser and 980 nm diode laser and then divided into five groups based on the final energy--200, 400, 600, 800 and 1,000 J groups. The ablation quality of nucleus pulposus after radiation was recorded. The ablation quality of GSS was greater at higher radiation energies in both lasers. When compared at the same energy level, the ablation quality of GSS was greater in 980 nm diode laser than in 1,064 nm Nd:YAG laser. Statistical significance was observed in 200 and 400 J groups (P < 0.05) and in 600, 800 and 1,000 J groups (P < 0.01). Radiation with 980 nm diode laser showed better ablation ability than 1,064 nm Nd:YAG laser.

Finite Element Study of a Lumbar Intervertebral Disc Nucleus Replacement Device.

PubMed

Coogan, Jessica S; Francis, W Loren; Eliason, Travis D; Bredbenner, Todd L; Stemper, Brian D; Yoganandan, Narayan; Pintar, Frank A; Nicolella, Daniel P

2016-01-01

Nucleus replacement technologies are a minimally invasive alternative to spinal fusion and total disc replacement that have the potential to reduce pain and restore motion for patients with degenerative disc disease. Finite element modeling can be used to determine the biomechanics associated with nucleus replacement technologies. The current study focuses on a new nucleus replacement device designed as a conforming silicone implant with an internal void. A validated finite element model of the human lumbar L3-L4 motion segment was developed and used to investigate the influence of the nucleus replacement device on spine biomechanics. In addition, the effect of device design changes on biomechanics was determined. A 3D, L3-L4 finite element model was constructed from medical imaging data. Models were created with the normal intact nucleus, the nucleus replacement device, and a solid silicone implant. Probabilistic analysis was performed on the normal model to provide quantitative validation metrics. Sensitivity analysis was performed on the silicone Shore A durometer of the device. Models were loaded under axial compression followed by flexion/extension, lateral bending, or axial rotation. Compressive displacement, endplate stresses, reaction moment, and annulus stresses were determined and compared between the different models. The novel nucleus replacement device resulted in similar compressive displacement, endplate stress, and annulus stress and slightly higher reaction moment compared with the normal nucleus. The solid implant resulted in decreased displacement, increased endplate stress, decreased annulus stress, and decreased reaction moment compared with the novel device. With increasing silicone durometer, compressive displacement decreased, endplate stress increased, reaction moment increased, and annulus stress decreased. Finite element analysis was used to show that the novel nucleus replacement device results in similar biomechanics compared with the normal intact nucleus.

Finite Element Study of a Lumbar Intervertebral Disc Nucleus Replacement Device

PubMed Central

Coogan, Jessica S.; Francis, W. Loren; Eliason, Travis D.; Bredbenner, Todd L.; Stemper, Brian D.; Yoganandan, Narayan; Pintar, Frank A.; Nicolella, Daniel P.

2016-01-01

Nucleus replacement technologies are a minimally invasive alternative to spinal fusion and total disc replacement that have the potential to reduce pain and restore motion for patients with degenerative disc disease. Finite element modeling can be used to determine the biomechanics associated with nucleus replacement technologies. The current study focuses on a new nucleus replacement device designed as a conforming silicone implant with an internal void. A validated finite element model of the human lumbar L3–L4 motion segment was developed and used to investigate the influence of the nucleus replacement device on spine biomechanics. In addition, the effect of device design changes on biomechanics was determined. A 3D, L3–L4 finite element model was constructed from medical imaging data. Models were created with the normal intact nucleus, the nucleus replacement device, and a solid silicone implant. Probabilistic analysis was performed on the normal model to provide quantitative validation metrics. Sensitivity analysis was performed on the silicone Shore A durometer of the device. Models were loaded under axial compression followed by flexion/extension, lateral bending, or axial rotation. Compressive displacement, endplate stresses, reaction moment, and annulus stresses were determined and compared between the different models. The novel nucleus replacement device resulted in similar compressive displacement, endplate stress, and annulus stress and slightly higher reaction moment compared with the normal nucleus. The solid implant resulted in decreased displacement, increased endplate stress, decreased annulus stress, and decreased reaction moment compared with the novel device. With increasing silicone durometer, compressive displacement decreased, endplate stress increased, reaction moment increased, and annulus stress decreased. Finite element analysis was used to show that the novel nucleus replacement device results in similar biomechanics compared with the normal intact nucleus. PMID:27990418

Size Fluctuations of Near Critical Nuclei and Gibbs Free Energy for Nucleation of BDA on Cu(001)

NASA Astrophysics Data System (ADS)

Schwarz, Daniel; van Gastel, Raoul; Zandvliet, Harold J. W.; Poelsema, Bene

2012-07-01

We present a low-energy electron microscopy study of nucleation and growth of BDA on Cu(001) at low supersaturation. At sufficiently high coverage, a dilute BDA phase coexists with c(8×8) crystallites. The real-time microscopic information allows a direct visualization of near-critical nuclei, determination of the supersaturation and the line tension of the crystallites, and, thus, derivation of the Gibbs free energy for nucleation. The resulting critical nucleus size nicely agrees with the measured value. Nuclei up to 4-6 times larger still decay with finite probability, urging reconsideration of the classic perception of a critical nucleus.

Size fluctuations of near critical nuclei and Gibbs free energy for nucleation of BDA on Cu(001).

PubMed

Schwarz, Daniel; van Gastel, Raoul; Zandvliet, Harold J W; Poelsema, Bene

2012-07-06

We present a low-energy electron microscopy study of nucleation and growth of BDA on Cu(001) at low supersaturation. At sufficiently high coverage, a dilute BDA phase coexists with c(8×8) crystallites. The real-time microscopic information allows a direct visualization of near-critical nuclei, determination of the supersaturation and the line tension of the crystallites, and, thus, derivation of the Gibbs free energy for nucleation. The resulting critical nucleus size nicely agrees with the measured value. Nuclei up to 4-6 times larger still decay with finite probability, urging reconsideration of the classic perception of a critical nucleus.

Radio imaging of the very-high-energy gamma-ray emission region in the central engine of a radio galaxy.

PubMed

Acciari, V A; Aliu, E; Arlen, T; Bautista, M; Beilicke, M; Benbow, W; Bradbury, S M; Buckley, J H; Bugaev, V; Butt, Y; Byrum, K; Cannon, A; Celik, O; Cesarini, A; Chow, Y C; Ciupik, L; Cogan, P; Cui, W; Dickherber, R; Fegan, S J; Finley, J P; Fortin, P; Fortson, L; Furniss, A; Gall, D; Gillanders, G H; Grube, J; Guenette, R; Gyuk, G; Hanna, D; Holder, J; Horan, D; Hui, C M; Humensky, T B; Imran, A; Kaaret, P; Karlsson, N; Kieda, D; Kildea, J; Konopelko, A; Krawczynski, H; Krennrich, F; Lang, M J; LeBohec, S; Maier, G; McCann, A; McCutcheon, M; Millis, J; Moriarty, P; Ong, R A; Otte, A N; Pandel, D; Perkins, J S; Petry, D; Pohl, M; Quinn, J; Ragan, K; Reyes, L C; Reynolds, P T; Roache, E; Roache, E; Rose, H J; Schroedter, M; Sembroski, G H; Smith, A W; Swordy, S P; Theiling, M; Toner, J A; Varlotta, A; Vincent, S; Wakely, S P; Ward, J E; Weekes, T C; Weinstein, A; Williams, D A; Wissel, S; Wood, M; Walker, R C; Davies, F; Hardee, P E; Junor, W; Ly, C; Aharonian, F; Akhperjanian, A G; Anton, G; Barres de Almeida, U; Bazer-Bachi, A R; Becherini, Y; Behera, B; Bernlöhr, K; Bochow, A; Boisson, C; Bolmont, J; Borrel, V; Brucker, J; Brun, F; Brun, P; Bühler, R; Bulik, T; Büsching, I; Boutelier, T; Chadwick, P M; Charbonnier, A; Chaves, R C G; Cheesebrough, A; Chounet, L-M; Clapson, A C; Coignet, G; Dalton, M; Daniel, M K; Davids, I D; Degrange, B; Deil, C; Dickinson, H J; Djannati-Ataï, A; Domainko, W; Drury, L O'C; Dubois, F; Dubus, G; Dyks, J; Dyrda, M; Egberts, K; Emmanoulopoulos, D; Espigat, P; Farnier, C; Feinstein, F; Fiasson, A; Förster, A; Fontaine, G; Füssling, M; Gabici, S; Gallant, Y A; Gérard, L; Gerbig, D; Giebels, B; Glicenstein, J F; Glück, B; Goret, P; Göhring, D; Hauser, D; Hauser, M; Heinz, S; Heinzelmann, G; Henri, G; Hermann, G; Hinton, J A; Hoffmann, A; Hofmann, W; Holleran, M; Hoppe, S; Horns, D; Jacholkowska, A; de Jager, O C; Jahn, C; Jung, I; Katarzyński, K; Katz, U; Kaufmann, S; Kendziorra, E; Kerschhaggl, M; Khangulyan, D; Khélifi, B; Keogh, D; Kluźniak, W; Kneiske, T; Komin, Nu; Kosack, K; Lamanna, G; Lenain, J-P; Lohse, T; Marandon, V; Martin, J M; Martineau-Huynh, O; Marcowith, A; Maurin, D; McComb, T J L; Medina, M C; Moderski, R; Moulin, E; Naumann-Godo, M; de Naurois, M; Nedbal, D; Nekrassov, D; Nicholas, B; Niemiec, J; Nolan, S J; Ohm, S; Olive, J-F; de Oña Wilhelmi, E; Orford, K J; Ostrowski, M; Panter, M; Paz Arribas, M; Pedaletti, G; Pelletier, G; Petrucci, P-O; Pita, S; Pühlhofer, G; Punch, M; Quirrenbach, A; Raubenheimer, B C; Raue, M; Rayner, S M; Renaud, M; Rieger, F; Ripken, J; Rob, L; Rosier-Lees, S; Rowell, G; Rudak, B; Rulten, C B; Ruppel, J; Sahakian, V; Santangelo, A; Schlickeiser, R; Schöck, F M; Schröder, R; Schwanke, U; Schwarzburg, S; Schwemmer, S; Shalchi, A; Sikora, M; Skilton, J L; Sol, H; Spangler, D; Stawarz, Ł; Steenkamp, R; Stegmann, C; Stinzing, F; Superina, G; Szostek, A; Tam, P H; Tavernet, J-P; Terrier, R; Tibolla, O; Tluczykont, M; van Eldik, C; Vasileiadis, G; Venter, C; Venter, L; Vialle, J P; Vincent, P; Vivier, M; Völk, H J; Volpe, F; Wagner, S J; Ward, M; Zdziarski, A A; Zech, A; Anderhub, H; Antonelli, L A; Antoranz, P; Backes, M; Baixeras, C; Balestra, S; Barrio, J A; Bastieri, D; Becerra González, J; Becker, J K; Bednarek, W; Berger, K; Bernardini, E; Biland, A; Bock, R K; Bonnoli, G; Bordas, P; Borla Tridon, D; Bosch-Ramon, V; Bose, D; Braun, I; Bretz, T; Britvitch, I; Camara, M; Carmona, E; Commichau, S; Contreras, J L; Cortina, J; Costado, M T; Covino, S; Curtef, V; Dazzi, F; De Angelis, A; De Cea del Pozo, E; Delgado Mendez, C; De los Reyes, R; De Lotto, B; De Maria, M; De Sabata, F; Dominguez, A; Dorner, D; Doro, M; Elsaesser, D; Errando, M; Ferenc, D; Fernández, E; Firpo, R; Fonseca, M V; Font, L; Galante, N; García López, R J; Garczarczyk, M; Gaug, M; Goebel, F; Hadasch, D; Hayashida, M; Herrero, A; Hildebrand, D; Höhne-Mönch, D; Hose, J; Hsu, C C; Jogler, T; Kranich, D; La Barbera, A; Laille, A; Leonardo, E; Lindfors, E; Lombardi, S; Longo, F; López, M; Lorenz, E; Majumdar, P; Maneva, G; Mankuzhiyil, N; Mannheim, K; Maraschi, L; Mariotti, M; Martínez, M; Mazin, D; Meucci, M; Miranda, J M; Mirzoyan, R; Miyamoto, H; Moldón, J; Moles, M; Moralejo, A; Nieto, D; Nilsson, K; Ninkovic, J; Oya, I; Paoletti, R; Paredes, J M; Pasanen, M; Pascoli, D; Pauss, F; Pegna, R G; Perez-Torres, M A; Persic, M; Peruzzo, L; Prada, F; Prandini, E; Puchades, N; Reichardt, I; Rhode, W; Ribó, M; Rico, J; Rissi, M; Robert, A; Rügamer, S; Saggion, A; Saito, T Y; Salvati, M; Sanchez-Conde, M; Satalecka, K; Scalzotto, V; Scapin, V; Schweizer, T; Shayduk, M; Shore, S N; Sidro, N; Sierpowska-Bartosik, A; Sillanpää, A; Sitarek, J; Sobczynska, D; Spanier, F; Stamerra, A; Stark, L S; Takalo, L; Tavecchio, F; Temnikov, P; Tescaro, D; Teshima, M; Torres, D F; Turini, N; Vankov, H; Wagner, R M; Zabalza, V; Zandanel, F; Zanin, R; Zapatero, J

2009-07-24

The accretion of matter onto a massive black hole is believed to feed the relativistic plasma jets found in many active galactic nuclei (AGN). Although some AGN accelerate particles to energies exceeding 10(12) electron volts and are bright sources of very-high-energy (VHE) gamma-ray emission, it is not yet known where the VHE emission originates. Here we report on radio and VHE observations of the radio galaxy Messier 87, revealing a period of extremely strong VHE gamma-ray flares accompanied by a strong increase of the radio flux from its nucleus. These results imply that charged particles are accelerated to very high energies in the immediate vicinity of the black hole.

Effects of shear flow on phase nucleation and crystallization.

PubMed

Mura, Federica; Zaccone, Alessio

2016-04-01

Classical nucleation theory offers a good framework for understanding the common features of new phase formation processes in metastable homogeneous media at rest. However, nucleation processes in liquids are ubiquitously affected by hydrodynamic flow, and there is no satisfactory understanding of whether shear promotes or slows down the nucleation process. We developed a classical nucleation theory for sheared systems starting from the molecular level of the Becker-Doering master kinetic equation and we analytically derived a closed-form expression for the nucleation rate. The theory accounts for the effect of flow-mediated transport of molecules to the nucleus of the new phase, as well as for the mechanical deformation imparted to the nucleus by the flow field. The competition between flow-induced molecular transport, which accelerates nucleation, and flow-induced nucleus straining, which lowers the nucleation rate by increasing the nucleation energy barrier, gives rise to a marked nonmonotonic dependence of the nucleation rate on the shear rate. The theory predicts an optimal shear rate at which the nucleation rate is one order of magnitude larger than in the absence of flow.

The kinetics of nucleated polymerizations at high concentrations: amyloid fibril formation near and above the "supercritical concentration".

PubMed

Powers, Evan T; Powers, David L

2006-07-01

The formation of amyloid and other types of protein fibrils is thought to proceed by a nucleated polymerization mechanism. One of the most important features commonly associated with nucleated polymerizations is a strong dependence of the rate on the concentration. However, the dependence of fibril formation rates on concentration can weaken and nearly disappear as the concentration increases. Using numerical solutions to the rate equations for nucleated polymerization and analytical solutions to some limiting cases, we examine this phenomenon and show that it is caused by the concentration approaching and then exceeding the equilibrium constant for dissociation of monomers from species smaller than the nucleus, a quantity we have named the "supercritical concentration". When the concentration exceeds the supercritical concentration, the monomer, not the nucleus, is the highest-energy species on the fibril formation pathway, and the fibril formation reaction behaves initially like an irreversible polymerization. We also derive a relation that can be used in a straightforward method for determining the nucleus size and the supercritical concentration from experimental measurements of fibril formation rates.

The Kinetics of Nucleated Polymerizations at High Concentrations: Amyloid Fibril Formation Near and Above the “Supercritical Concentration”

PubMed Central

Powers, Evan T.; Powers, David L.

2006-01-01

The formation of amyloid and other types of protein fibrils is thought to proceed by a nucleated polymerization mechanism. One of the most important features commonly associated with nucleated polymerizations is a strong dependence of the rate on the concentration. However, the dependence of fibril formation rates on concentration can weaken and nearly disappear as the concentration increases. Using numerical solutions to the rate equations for nucleated polymerization and analytical solutions to some limiting cases, we examine this phenomenon and show that it is caused by the concentration approaching and then exceeding the equilibrium constant for dissociation of monomers from species smaller than the nucleus, a quantity we have named the “supercritical concentration”. When the concentration exceeds the supercritical concentration, the monomer, not the nucleus, is the highest-energy species on the fibril formation pathway, and the fibril formation reaction behaves initially like an irreversible polymerization. We also derive a relation that can be used in a straightforward method for determining the nucleus size and the supercritical concentration from experimental measurements of fibril formation rates. PMID:16603497

Sim1 haploinsufficiency impairs melanocortin-mediated anorexia and activation of paraventricular nucleus neurons.

PubMed

Kublaoui, Bassil M; Holder, J Lloyd; Gemelli, Terry; Zinn, Andrew R

2006-10-01

Single-minded 1 (SIM1) is one of only six genes implicated in human monogenic obesity. Haploinsufficiency of this hypothalamic transcription factor is associated with hyperphagic obesity and increased linear growth in both humans and mice. Additionally, Sim1 heterozygous mice show enhanced hyperphagia and obesity in response to a high-fat diet. Thus the phenotype of Sim1 haploinsufficiency is similar to that of agouti yellow (Ay), and melanocortin 4 receptor (Mc4r) knockout mice, both of which are defective in hypothalamic melanocortin signaling. Sim1 and Mc4r are both expressed in the paraventricular nucleus (PVN). Here we report that Sim1 heterozygous mice, which have normal energy expenditure, are hyperphagic despite having elevated hypothalamic proopiomelanocortin (Pomc) expression. In response to the melanocortin agonist melanotan-2 (MTII) they exhibit a blunted suppression of feeding yet increase their energy expenditure normally. They also fail to activate PVN neurons in response to the drug at a dose that induces robust c-Fos expression in a subset of Sim1 PVN neurons in wild-type mice. The resistance to melanocortin signaling in Sim1 heterozygotes is not due to a reduced number of Sim1 neurons in the PVN. Hypothalamic Sim1 gene expression is induced by leptin and MTII treatment. Our results demonstrate that Sim1 heterozygotes are resistant to hypothalamic melanocortin signaling and suggest that Sim1-expressing PVN neurons regulate feeding, but not energy expenditure, in response to melanocortin signaling.

Neuroanatomy of melanocortin-4 receptor pathway in the lateral hypothalamic area

PubMed Central

Cui, Huxing; Sohn, Jong-Woo; Gautron, Laurent; Funahashi, Hisayuki; Williams, Kevin W.; Elmquist, Joel K.; Lutter, Michael

2013-01-01

The central melanocortin system regulates body energy homeostasis including the melanocortin-4 receptor (MC4R). The lateral hypothalamic area (LHA) receives dense melanocortinergic inputs from the arcuate nucleus of hypothalamus and regulates multiple processes including food intake, reward behaviors and autonomic function. Using a mouse line in which green fluorescent protein (GFP) is expressed under control of MC4R gene promoter, we systemically investigated MC4R signaling in the LHA by combining double immunohistochemistry, electrophysiology and retrograde tracing techniques. We found that LHA MC4R-GFP neurons co-express neurotensin as well as the leptin receptor but not with other peptide neurotransmitters found in the LHA including orexin, melanin concentrating hormone and nesfatin-1. Furthermore, electrophysiological recording demonstrated that leptin, but not the MC4R agonist melanotan II, hyperpolarizes the majority of LHA MC4R-GFP neurons in an ATP-sensitive potassium channel-dependent manner. Retrograde tracing revealed that LHA MC4R-GFP neurons do not project to the ventral tegmental area, dorsal raphe nucleus, nucleus accumbens and spinal cord, and only limited number of neurons project to the nucleus of solitary tract and parabrachial nucleus. Our findings provide new insight into MC4R signaling in the LHA and its potential implication in homeostatic regulation of body energy balance. PMID:22605619

Applications of the Trojan Horse method in nuclear astrophysics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Spitaleri, Claudio, E-mail: spitaleri@lns.infn.it

2015-02-24

The study of the energy production in stars and related nucleosyntesis processes requires increasingly precise knowledge of the nuclear reaction cross section and reaction rates at interaction energy. In order to overcome the experimental difficulties, arising from small cross-sections involved in charge particle induced reactions at astrophysical energies, and from the presence of electron screening, it was necessary to introduce indirect methods. Trough these methods it is possible to measure cross sections at very small energies and retrieve information on electron screening effect when ultra-low energy direct measurements are available. The Trojan Horse Method (THM) represents the indirect technique tomore » determine the bare nucleus astrophysical S-factor for reactions between charged particles at astrophysical energies. The basic theory of the THM is discussed in the case of non-resonant.« less

The free growth criterion for grain initiation in TiB 2 inoculated γ-titanium aluminide based alloys

NASA Astrophysics Data System (ADS)

Gosslar, D.; Günther, R.

2014-02-01

γ-titanium aluminide (γ-TiAl) based alloys enable for the design of light-weight and high-temperature resistant engine components. This work centers on a numerical study of the condition for grain initiation during solidification of TiB2 inoculated γ-TiAl based alloys. Grain initiation is treated according to the so-called free growth criterion. This means that the free growth barrier for grain initiation is determined by the maximum interfacial mean curvature between a nucleus and the melt. The strategy presented in this paper relies on iteratively increasing the volume of a nucleus, which partially wets a hexagonal TiB2 crystal, minimizing the interfacial energy and calculating the corresponding interfacial curvature. The hereby obtained maximum curvature yields a scaling relation between the size of TiB2 crystals and the free growth barrier. Comparison to a prototypical TiB2 crystal in an as cast γ-TiAl based alloy allowed then to predict the free growth barrier prevailing under experimental conditions. The validity of the free growth criterion is discussed by an interfacial energy criterion.

Systematic study of rapidity dispersion parameter in high energy nucleus-nucleus interactions

NASA Astrophysics Data System (ADS)

Bhattacharyya, Swarnapratim; Haiduc, Maria; Neagu, Alina Tania; Firu, Elena

2014-03-01

A systematic study of rapidity dispersion parameter as a quantitative measure of clustering of particles has been carried out in the interactions of 16O, 28Si and 32S projectiles at 4.5 A GeV/c with heavy (AgBr) and light (CNO) groups of targets present in the nuclear emulsion. For all the interactions, the total ensemble of events has been divided into four overlapping multiplicity classes depending on the number of shower particles. For all the interactions and for each multiplicity class, the rapidity dispersion parameter values indicate the occurrence of clusterization during the multiparticle production at Dubna energy. The measured rapidity dispersion parameter values are found to decrease with the increase of average multiplicity for all the interactions. The dependence of rapidity dispersion parameter on the average multiplicity can be successfully described by a relation D(η) = a + b + c2. The experimental results have been compared with the results obtained from the analysis of Monte Carlo simulated (MC-RAND) events. MC-RAND events show weaker clusterization among the pions in comparison to the experimental data.

Effect of intermittent hypoxia on arcuate nucleus in the leptin-deficient rat.

PubMed

Ciriello, John; Moreau, Jason M; McCoy, Aaron; Jones, Douglas L

2016-07-28

Intermittent hypoxia (IH) is a major pathophysiological consequence of obstructive sleep apnea. Recently, it has been shown that IH results in changes in body energy balance, leptin secretion and concomitant alterations in arcuate nucleus (ARC). In this study, the role of leptin on these changes was investigated in leptin-deficient rats exposed to IH or normoxic control conditions. Body weights, consumatory and locomotor behaviours, and protein signaling in ARC were assessed immediately after IH exposure. Compared to normoxia, IH altered body weight, food intake, locomotor pattern, and the plasma concentration of leptin and angiotensin II in the wild-type rat. However, these changes were not observed in the leptin-deficient rat. Within ARC of wild-type animals, IH increased phosphorylated signal transducer and activator of transcription 3 and pro-opiomelanocortin protein expression, but not in the leptin-deficient rat. The long-form leptin receptor protein expression was not altered following IH in either rat strain. These data suggest that leptin is involved in mediating the alterations to body energy balance and ARC activity following IH. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Nineteenth International Cosmic Ray Conference. HE Sessions, Volume 6

NASA Technical Reports Server (NTRS)

Jones, F. C. (Compiler)

1985-01-01

Papers contributed to the 19th International Cosmic Ray Conference which address high energy interactions and related phenomena are compiled. Particular topic areas include cross sections; particle production; nuclei and nuclear matter; nucleus-nucleus collisions; gamma ray and hadron spectra; C-jets, a-jets, and super families; and emulsion chamber simulations.

The interaction of amylin with other hormones in the control of eating.

PubMed

Lutz, T A

2013-02-01

Twenty years of research established amylin as an important control of energy homeostasis. Amylin controls nutrient and energy fluxes by reducing energy intake, by modulating nutrient utilization via an inhibition of postprandial glucagon secretion and by increasing energy disposal via a prevention of compensatory decreases of energy expenditure in weight reduced individuals. Like many other gastrointestinal hormones, amylin is secreted in response to meals and it reduces eating by promoting meal-ending satiation. Not surprisingly, amylin interacts with many of these hormones to control eating. These interactions seem to occur at different levels because amylin seems to mediate the eating inhibitory effect of some of these gastrointestinal hormones, and the combination of some of these hormones seems to lead to a stronger reduction in eating than single hormones alone. Amylin's effect on eating is thought to be mediated by a stimulation of specific amylin receptors in the area postrema. Secondary brain sites that were defined to mediate amylin action - and hence potential additional sites of interaction with other hormones - include the nucleus of the solitary tract, the lateral parabrachial nucleus, the lateral hypothalamic area and other hypothalamic nuclei. The focus of this review is to summarize the current knowledge of amylin interactions in the control of eating. In most cases, these interactions have only been studied at a descriptive rather than a mechanistic level and despite the clear knowledge on primary sites of amylin action, the interaction sites between amylin and other hormones are often unknown. © 2012 Blackwell Publishing Ltd.

ROCK1 in AgRP neurons regulates energy expenditure and locomotor activity in male mice.

PubMed

Huang, Hu; Lee, Seung Hwan; Ye, Chianping; Lima, Ines S; Oh, Byung-Chul; Lowell, Bradford B; Zabolotny, Janice M; Kim, Young-Bum

2013-10-01

Normal leptin signaling is essential for the maintenance of body weight homeostasis. Proopiomelanocortin- and agouti-related peptide (AgRP)-producing neurons play critical roles in regulating energy metabolism. Our recent work demonstrates that deletion of Rho-kinase 1 (ROCK1) in the AgRP neurons of mice increased body weight and adiposity. Here, we report that selective loss of ROCK1 in AgRP neurons caused a significant decrease in energy expenditure and locomotor activity of mice. These effects were independent of any change in food intake. Furthermore, AgRP neuron-specific ROCK1-deficient mice displayed central leptin resistance, as evidenced by impaired Signal Transducer and Activator of Transcription 3 activation in response to leptin administration. Leptin's ability to hyperpolarize and decrease firing rate of AgRP neurons was also abolished in the absence of ROCK1. Moreover, diet-induced and genetic forms of obesity resulted in reduced ROCK1 activity in murine arcuate nucleus. Of note, high-fat diet also impaired leptin-stimulated ROCK1 activity in arcuate nucleus, suggesting that a defect in hypothalamic ROCK1 activity may contribute to the pathogenesis of central leptin resistance in obesity. Together, these data demonstrate that ROCK1 activation in hypothalamic AgRP neurons is required for the homeostatic regulation of energy expenditure and adiposity. These results further support previous work identifying ROCK1 as a key regulator of energy balance and suggest that targeting ROCK1 in the hypothalamus may lead to development of antiobesity therapeutics.

Overnight Fasting Regulates Inhibitory Tone to Cholinergic Neurons of the Dorsomedial Nucleus of the Hypothalamus

PubMed Central

Groessl, Florian; Jeong, Jae Hoon; Talmage, David A.; Role, Lorna W.; Jo, Young-Hwan

2013-01-01

The dorsomedial nucleus of the hypothalamus (DMH) contributes to the regulation of overall energy homeostasis by modulating energy intake as well as energy expenditure. Despite the importance of the DMH in the control of energy balance, DMH-specific genetic markers or neuronal subtypes are poorly defined. Here we demonstrate the presence of cholinergic neurons in the DMH using genetically modified mice that express enhanced green florescent protein (eGFP) selectively in choline acetyltransferase (Chat)-neurons. Overnight food deprivation increases the activity of DMH cholinergic neurons, as shown by induction of fos protein and a significant shift in the baseline resting membrane potential. DMH cholinergic neurons receive both glutamatergic and GABAergic synaptic input, but the activation of these neurons by an overnight fast is due entirely to decreased inhibitory tone. The decreased inhibition is associated with decreased frequency and amplitude of GABAergic synaptic currents in the cholinergic DMH neurons, while glutamatergic synaptic transmission is not altered. As neither the frequency nor amplitude of miniature GABAergic or glutamatergic postsynaptic currents is affected by overnight food deprivation, the fasting-induced decrease in inhibitory tone to cholinergic neurons is dependent on superthreshold activity of GABAergic inputs. This study reveals that cholinergic neurons in the DMH readily sense the availability of nutrients and respond to overnight fasting via decreased GABAergic inhibitory tone. As such, altered synaptic as well as neuronal activity of DMH cholinergic neurons may play a critical role in the regulation of overall energy homeostasis. PMID:23585854

The Role of Nuclear Fragmentation in Particle Therapy and Space Radiation Protection.

PubMed

Zeitlin, Cary; La Tessa, Chiara

2016-01-01

The transport of the so-called HZE particles (those having high charge, Z, and energy, E) through matter is crucially important both in space radiation protection and in the clinical setting where heavy ions are used for cancer treatment. HZE particles are usually considered those having Z > 1, though sometimes Z > 2 is meant. Transport physics is governed by two types of interactions, electromagnetic (ionization energy loss) and nuclear. Models of transport, such as those used in treatment planning and space mission planning must account for both effects in detail. The theory of electromagnetic interactions is well developed, but nucleus-nucleus collisions are so complex that no fundamental physical theory currently describes them. Instead, interaction models are generally anchored to experimental data, which in some areas are far from complete. The lack of fundamental physics knowledge introduces uncertainties in the calculations of exposures and their associated risks. These uncertainties are greatly compounded by the much larger uncertainties in biological response to HZE particles. In this article, we discuss the role of nucleus-nucleus interactions in heavy charged particle therapy and in deep space, where astronauts will receive a chronic low dose from galactic cosmic rays (GCRs) and potentially higher short-term doses from sporadic, unpredictable solar energetic particles (SEPs). GCRs include HZE particles; SEPs typically do not and we, therefore, exclude them from consideration in this article. Nucleus-nucleus collisions can result in the breakup of heavy ions into lighter ions. In space, this is generally beneficial because dose and dose equivalent are, on the whole, reduced in the process. The GCRs can be considered a radiation field with a significant high-LET component; when they pass through matter, the high-LET component is attenuated, at the cost of a slight increase in the low-LET component. Not only are the standard measures of risk reduced by fragmentation, but it can be argued that fragmentation also reduces the uncertainties in risk calculations by shifting the LET distribution toward one that is more concentrated at low LET, where biological effects are better understood. We review previous work in this area, including measurements made by the Radiation Assessment Detector during its journey to Mars and while on the surface of Mars aboard the Curiosity rover. Transport of HZE is also critically important in heavy-ion therapy, as it is necessary to know the details of the radiation field at the treatment site. This field is substantially modified compared to the incident pure (or nearly pure) ion beam by the same mechanisms of energy loss and nuclear fragmentation that pertain to the transport of space radiation.

Optical-model abrasion cross sections for high-energy heavy ions

NASA Technical Reports Server (NTRS)

Townsend, L. W.

1981-01-01

Within the context of eikonal scattering theory, a generalized optical model potential approximation to the nucleus-nucleus multiple scattering series is used in an abrasion-ablation collision model to predict abrasion cross sections for relativistic projectile heavy ions. Unlike the optical limit of Glauber theory, which cannot be used for very light nuclei, the abrasion formalism is valid for any projectile target combination at any incident kinetic energy for which eikonal scattering theory can be utilized. Results are compared with experimental results and predictions from Glauber theory.

Investigation of charged-hadron production in proton–nucleus interactions at the energy of 50 GeV

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bordanovskii, A. Yu.; Volkov, A. A.; Elumahov, D. K.

2016-07-15

Cross sections for the production of high-transverse-momentum charged hadrons in proton–nucleus interactions at the incident-proton energy of 50 GeV were measured with the aid of the FODS double-arm spectrometer. Single hadrons (charged pions and protons) emitted at a c.m. angle of about 90° and high-effective-mass pairs of hadrons flying apart at a c.m. angle of 180° were detected simultaneously. Results on the production of single hadrons are presented.

Multiplicity of Charged Particles in Pion - Nucleus Interactions in an Emulsion at 200-GeV/c

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anzon, Z.V.; Gaitinov, A.Sh.; Eremenko, L.E.

1977-01-01

The experimental data on multiplicities of charged secondaries produced in pion-nucleus interactions in an emulsion at 200 Gev/c and correlations bet6ween them are presented and discussed. Parameters of multiplicity distributions are compared with the relevant ones at lower energies and with data from pA-interactions at 200 Gev/c. The multiplicity of heavily ionizing particles in {Pi}{sup -}A-interactions weakly depend on the incident energy. The KNO scaling is observed being the same for incident protons and pions.

Mass Defect from Nuclear Physics to Mass Spectral Analysis.

PubMed

Pourshahian, Soheil

2017-09-01

Mass defect is associated with the binding energy of the nucleus. It is a fundamental property of the nucleus and the principle behind nuclear energy. Mass defect has also entered into the mass spectrometry terminology with the availability of high resolution mass spectrometry and has found application in mass spectral analysis. In this application, isobaric masses are differentiated and identified by their mass defect. What is the relationship between nuclear mass defect and mass defect used in mass spectral analysis, and are they the same? Graphical Abstract ᅟ.

Development of a new method for measurement of neutron detector efficiency up to 20 MeV

DOE PAGES

Kornilov, N. V.; Grimes, S. M.; Massey, T. N.; ...

2014-09-03

A new approach to neutron detector efficiency has been taken. A neutron detector has been calibrated with a 252Cf source at low energy. The calibration can be extended to energies above 8 MeV based on the 252Cf results. The techniques uses the fact that the cross section for a symmetric reaction with nucleus of atomic number A yielding a final nucleus with atomic number (2A-1) and a neutron A + A → (2A – 1) + n. This reaction must be symmetric about 90° in the center-of-mass system. Furthermore, the laboratory energies for the neutrons at the paired energies differmore » substantially. Thus, an efficiency known at one of the two angles can be used to determine the efficiency to higher energies or, for a negative Q, to lower neutron energies.« less

Glucose concentrations modulate brain-derived neurotrophic factor responsiveness of neurones in the paraventricular nucleus of the hypothalamus.

PubMed

McIsaac, W; Ferguson, A V

2017-04-01

The hypothalamic paraventricular nucleus (PVN) is critical for normal energy balance and has been shown to contain high levels of both brain-derived neurotrophic factor (BDNF) and tropomyosin-receptor kinase B mRNA. Microinjections of BDNF into the PVN increase energy expenditure, suggesting that BDNF plays an important role in energy homeostasis through direct actions in this nucleus. The present study aimed to examine the postsynaptic effects of BDNF on the membrane potential of PVN neurones, and also to determine whether extracellular glucose concentrations modulated these effects. We used hypothalamic PVN slices from male Sprague-Dawley rats to perform whole cell current-clamp recordings from PVN neurones. BDNF was bath applied at a concentration of 2 nmol L -1 and the effects on membrane potential determined. BDNF caused depolarisations in 54% of neurones (n=25; mean±SEM, 8.9±1.2 mV) and hyperpolarisations in 23% (n=11; -6.7±1.4 mV), whereas the remaining cells were unaffected. These effects were maintained in the presence of tetrodotoxin (n=9; 56% depolarised, 22% hyperpolarised, 22% nonresponders), or the GABA a antagonist bicuculline (n=12; 42% depolarised, 17% hyperpolarised, 41% nonresponders), supporting the conclusion that these effects on membrane potential were postsynaptic. Current-clamp recordings from PVN neurones next examined the effects of BDNF on these neurones at varying extracellular glucose concentrations. Larger proportions of PVN neurones hyperpolarised in response to BDNF as the glucose concentrations decreased [10 mmol L -1 glucose 23% (n=11) of neurones hyperpolarised, whereas, at 0.2 mmol L -1 glucose, 71% showed hyperpolarising effects (n=12)]. Our findings reveal that BDNF has direct GABA A independent effects on PVN neurones, which are modulated by local glucose concentrations. The latter observation further emphasises the critical importance of using physiologically relevant conditions in an investigation of the central pathways involved in the regulation of energy homeostasis. © 2017 British Society for Neuroendocrinology.

Sci-Thur AM: YIS – 06: A Monte Carlo study of macro- and microscopic dose descriptors and the microdosimetric spread using detailed cellular models

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oliver, Patricia; Thomson, Rowan

2016-08-15

Purpose: To develop Monte Carlo models of cell clusters to investigate the relationships between macro- and microscopic dose descriptors, quantify the microdosimetric spread in energy deposition for subcellular targets, and determine how these results depend on the computational model. Methods: Microscopic tissue structure is modelled as clusters of 13 to 150 cells, with cell (nuclear) radii between 5 and 10 microns (2 and 9 microns). Energy imparted per unit mass (specific energy or dose) is scored in the nucleus (D{sub nuc}) and cytoplasm (D{sub cyt}) for incident photon energies from 20 to 370 keV. Dose-to-water (D{sub w,m}) and dose-to-medium (D{submore » m,m}) are compared to D{sub nuc} and D{sub cyt}. Single cells and single nuclear cavities are also simulated. Results: D{sub nuc} and D{sub cyt} are sensitive to the surrounding environment with deviations of up to 13% for a single nucleus/cell compared with a multicellular cluster. These dose descriptors vary with cell and nucleus size by up to 10%. D{sub nuc} and D{sub cyt} differ from D{sub w,m} and D{sub m,m} by up to 32%. The microdosimetric spread is sensitive to whether cells are arranged randomly or in a hexagonal lattice, and whether subcellular compartment sizes are sampled from a normal distribution or are constant throughout the cluster. Conclusions: D{sub nuc} and D{sub cyt} are sensitive to cell morphology, elemental composition and the presence of surrounding cells. The microdosimetric spread was investigated using realistic elemental compositions for the nucleus and cytoplasm, and depends strongly on subcellular compartment size, source energy and dose.« less

The entrance channel effects on the deexcitation ways of the same compound nucleus at a fixed excitation energy

NASA Astrophysics Data System (ADS)

Anastasi, A.; Mandaglio, G.; Curciarello, F.; Nasirov, A. K.; Fazio, G.; Giardina, G.

2018-05-01

The investigation of various properties of deexcitation of the same 220Th compound nucleus (CN), formed by the different mass (charge) asymmetric 16O+204Pb, 40Ar+180Hf, 82Se+138Ba and 96Zr+124Sn reactions is presented. The effective fission barrier < B fis > value, as a function of the excitation energy {E}CN* , determined for each intermediate excited nucleus reached along the deexcitation cascade of the CN obtained by the four considered reactions is strongly sensitive to the various orbital angular momentum L=ℓℏ distributions of CN formed with the same excitation energy {E}CN* by the various entrance channels. Therefore, the competition between the fission and evaporation of light particles (neutron, proton, and α-particle) processes along the deexcitation cascade of CN is dependent on the orbital angular momentum distribution of CN. In fact, the ratio between the evaporation residue cross sections obtained when also the charged particles are emitted and the ones obtained after neutron emission only for the same CN with a fixed excitation energy {E}CN* is sensitive to the mass (charge) asymmetry of the entrance channel.

Peculiarities of the electron energy spectrum in the Coulomb field of a superheavy nucleus

NASA Astrophysics Data System (ADS)

Voronov, B. L.; Gitman, D. M.; Levin, A. D.; Ferreira, R.

2016-05-01

We consider the peculiarities of the electron energy spectrum in the Coulomb field of a superheavy nucleus and discuss the long history of an incorrect interpretation of this problem in the case of a pointlike nucleus and its current correct solution. We consider the spectral problem in the case of a regularized Coulomb potential. For some special regularizations, we derive an exact equation for the point spectrum in the energy interval (-m,m) and find some of its solutions numerically. We also derive an exact equation for charges yielding bound states with the energy E = -m; some call them supercritical charges. We show the existence of an infinite number of such charges. Their existence does not mean that the oneparticle relativistic quantum mechanics based on the Dirac Hamiltonian with the Coulomb field of such charges is mathematically inconsistent, although it is physically unacceptable because the spectrum of the Hamiltonian is unbounded from below. The question of constructing a consistent nonperturbative second-quantized theory remains open, and the consequences of the existence of supercritical charges from the standpoint of the possibility of constructing such a theory also remain unclear.

Effects of amylin on eating and adiposity.

PubMed

Lutz, Thomas Alexander

2012-01-01

Amylin's best investigated function is to reduce eating via a meal size effect by promoting meal-ending satiation. This effect seems to depend on an activation of specific area postrema neurons. Brain areas that convey the neural signal to the forebrain include the nucleus of the solitary tract and the lateral parabrachial nucleus. Acute application of amylin modulates the activity of hypothalamic areas involved in the control of eating, namely, the lateral hypothalamic area and possibly the ventromedial hypothalamic nucleus. Amylin also interacts with other satiating signals, such as cholecystokinin, presumably in the brainstem. Interestingly, amylin also exhibits characteristics of adiposity signals; plasma levels of amylin are higher in obese individuals, chronic infusion of amylin into the brain reduces body weight gain and adiposity, and infusion of amylin antagonists increases adiposity. Furthermore, amylin maintains energy expenditure at higher levels than would be expected considering its body weight-lowering effect. However, much less is known (e.g., site of action, signaling pathways, differential activation of brain sites, and, most importantly, physiological relevance) with respect to its role as adiposity signal and regulator of energy expenditure than about its satiating action. Notwithstanding, and perhaps because amylin resistance does not seem to be a general and prohibitive concomitant of obesity, animal data and recent clinical data in humans indicate that amylin is a very promising candidate for the treatment of obesity. Amylin seems to be particularly effective when combined with other hormones such as leptin.

Monosodium glutamate-induced arcuate nucleus damage affects both natural torpor and 2DG-induced torpor-like hypothermia in Siberian hamsters.

PubMed

Pelz, Kimberly M; Routman, David; Driscoll, Joseph R; Kriegsfeld, Lance J; Dark, John

2008-01-01

Siberian hamsters (Phodopus sungorus) have the ability to express daily torpor and decrease their body temperature to approximately 15 degrees C, providing a significant savings in energy expenditure. Daily torpor in hamsters is cued by winterlike photoperiods and occurs coincident with the annual nadirs in body fat reserves and chronic leptin concentrations. To better understand the neural mechanisms underlying torpor, Siberian hamster pups were postnatally treated with saline or MSG to ablate arcuate nucleus neurons that likely possess leptin receptors. Body temperature was studied telemetrically in cold-acclimated (10 degrees C) male and female hamsters moved to a winterlike photoperiod (10:14-h light-dark cycle) (experiments 1 and 2) or that remained in a summerlike photoperiod (14:10-h light-dark cycle) (experiment 3). In experiment 1, even though other photoperiodic responses persisted, MSG-induced arcuate nucleus ablations prevented the photoperiod-dependent torpor observed in saline-treated Siberian hamsters. MSG-treated hamsters tended to possess greater fat reserves. To determine whether reductions in body fat would increase frequency of photoperiod-induced torpor after MSG treatment, hamsters underwent 2 wk of food restriction (70% of ad libitum) in experiment 2. Although food restriction did increase the frequency of torpor in both MSG- and saline-treated hamsters, it failed to normalize the proportion of MSG-treated hamsters undergoing photoperiod-dependent torpor. In experiment 3, postnatal MSG treatments reduced the proportion of hamsters entering 2DG-induced torpor-like hypothermia by approximately 50% compared with saline-treated hamsters (38 vs. 72%). In those MSG-treated hamsters that did become hypothermic, their minimum temperature during hypothermia was significantly greater than comparable saline-treated hamsters. We conclude that 1) arcuate nucleus mechanisms mediate photoperiod-induced torpor, 2) food-restriction-induced torpor may also be reduced by MSG treatments, and 3) arcuate nucleus neurons make an important, albeit partial, contribution to 2DG-induced torpor-like hypothermia.

Increases in food intake or food-seeking behavior induced by GABAergic, opioid, or dopaminergic stimulation of the nucleus accumbens: is it hunger?

PubMed

Hanlon, Erin C; Baldo, Brian A; Sadeghian, Ken; Kelley, Ann E

2004-03-01

Previous work has shown that stimulation of GABAergic, opioid, or dopaminergic systems within the nucleus accumbens modulates food intake and food-seeking behavior. However, it is not known whether such stimulation mimics a motivational state of food deprivation that commonly enables animals to learn a new operant response to obtain food. In order to address this question, acquisition of lever pressing for food in hungry animals was compared with acquisition in non-food-deprived rats subjected to various nucleus accumbens drug treatments. All animals were given the opportunity to learn an instrumental response (a lever press) to obtain a food pellet. Prior to training, ad lib-fed rats were infused with the gamma-aminobutyric acid (GABA)A agonist muscimol (100 ng/0.5 microl per side) or the mu-opioid receptor agonist D-Ala2, N-me-Phe4, Gly-ol5-enkephalin (DAMGO, 0.25 microg/0.5 microl per side), or saline into the nucleus accumbens shell (AcbSh). The indirect dopamine agonist amphetamine (10 microg/0.5 microl per side) was infused into the AcbSh or nucleus accumbens core (AcbC) of ad lib-fed rats. An additional group was food deprived and infused with saline in the AcbSh. Chow and sugar pellet intake responses after drug treatments were also evaluated in free-feeding tests. Muscimol, DAMGO, or amphetamine did not facilitate acquisition of lever pressing for food, despite clearly increasing food intake in free-feeding tests. In contrast, food-deprived animals rapidly learned the task. These findings suggest that pharmacological stimulation of any of these neurochemical systems in isolation is insufficient to enable acquisition of a food-reinforced operant task. Thus, these selective processes, while likely involved in control of food intake and food-seeking behavior, appear unable to recapitulate the conditions necessary to mimic the state of negative energy balance.

Statistical analysis of the distribution of chromosome aberrations in human lymphocytes induced by low and high energy heavy ions

NASA Astrophysics Data System (ADS)

Deperas-Standylo, Joanna; Lee, Ryonfa; Nasonova, Elena; Ritter, Sylvia; Gudowska-Nowak, Ewa; Kac, M.; Smoluchowski, M.

Differences in the track structure of high LET (Linear Energy Transfer) particles are clearly visible on chromosomal level, in particular in the number of lesions produced by an ion traversal through a cell nucleus and in the distribution of aberrations among the cells. In the present study we focus on the effects of low energy C-and Cr-ions (<10 MeV/u) in comparison with high energy C-ions (90 MeV/u). For the experiments human lymphocytes were exposed to 9.5 MeV/u C-ions, 4.1 MeV/u Cr-ions or 90 MeV/u C-ions with LET values of 175 keV/µm, 3160 keV/µm and 29 keV/µm, respectively. Chromosome aberrations were measured at several post-irradiation sampling times (48, 60, 72 and 84h) in first cycle metaphases following Giemsa-staining. For 90 MeV/u C-ions, where the track radius is larger than the cell nucleus, the distribution of aberrations did not change significantly with sampling time and has been well described by Poisson statistics. In contrast, for low energy C-ions, where the track radius is smaller than the cell nucleus, distribution of aberration strongly deviates from uni-modal and displays two peaks representative for subpopulations of non-hit and hit cells, respectively. Following this pattern, also damage-dependent cell cycle delay was observed. At 48 h after irradiation a high number of undamaged and probably unhit cells was found to reach mitosis. This number of undamaged cells decreased further with sampling time, while the frequencies of cells carrying aberrations (1-11 per cell) were increasing. All distributions were found to conform a compound Poisson (Neyman-type A) statistics which allows estimating the average number of particle traversals through a cell nucleus and the average number of aberrations induced by one particle traversal. Similar response has also been observed at 48h after Cr-ion exposure. In this case, however, non-aberrant cells have been found to dominate in the population even at later sampling times and a low number of heavily damaged cells up to 24 aberrations have been detected. Accordingly, the distribution of aberrations in cells collected at >48 h could not be then described by a standard Neyman statistics. Obtained results suggest that most cells hit by more than one Cr-ion do not reach mitosis. This observation was confirmed by parallel measurements showing that Cr-ion exposure produces a high fraction of apoptotic cells.

Forward-backward emission of target evaporated fragments in high energy nucleus-nucleus collisions

NASA Astrophysics Data System (ADS)

Zhang, Zhi; Ma, Tian-Li; Zhang, Dong-Hai

2015-10-01

The multiplicity distribution, multiplicity moment, scaled variance, entropy and reduced entropy of target evaporated fragments emitted in forward and backward hemispheres in 12 A GeV 4He, 3.7 A GeV 16O, 60 A GeV 16O, 1.7 A GeV 84Kr and 10.7 A GeV 197Au -induced emulsion heavy target (AgBr) interactions are investigated. It is found that the multiplicity distribution of target evaporated fragments emitted in both forward and backward hemispheres can be fitted by a Gaussian distribution. The multiplicity moments of target evaporated particles emitted in the forward and backward hemispheres increase with the order of the moment q, and the second-order multiplicity moment is energy independent over the entire energy range for all the interactions in the forward and backward hemisphere. The scaled variance, a direct measure of multiplicity fluctuations, is close to one for all the interactions, which indicate a correlation among the produced particles. The entropy of target evaporated fragments emitted in both forward and backward hemispheres are the same within experimental errors. Supported by National Science Foundation of China (11075100), Natural Science Foundation of Shanxi Province (2011011001-2) and the Shanxi Provincial Foundation for Returned Overseas Chinese Scholars, (2011-058)

Visualized kinematics code for two-body nuclear reactions

NASA Astrophysics Data System (ADS)

Lee, E. J.; Chae, K. Y.

2016-05-01

The one or few nucleon transfer reaction has been a great tool for investigating the single-particle properties of a nucleus. Both stable and exotic beams are utilized to study transfer reactions in normal and inverse kinematics, respectively. Because many energy levels of the heavy recoil from the two-body nuclear reaction can be populated by using a single beam energy, identifying each populated state, which is not often trivial owing to high level-density of the nucleus, is essential. For identification of the energy levels, a visualized kinematics code called VISKIN has been developed by utilizing the Java programming language. The development procedure, usage, and application of the VISKIN is reported.

3 parton production at DIS at small x

NASA Astrophysics Data System (ADS)

Hentschinski, Martin

2018-01-01

We use the spinor helicity formalism to calculate the cross section for production of three partons of a given polarization in Deep Inelastic Scattering (DIS) off proton and nucleus targets at small Bjorken x. The target proton or nucleus is treated as a classical color field (shock wave) from which the produced partons scatter multiple times. The resulting expressions are used to study azimuthal angular correlations between produced partons in order to probe the gluon structure of the target hadron or nucleus as well as to study energy loss in DIS reactions.

Resonance production in high energy collisions from small to big systems

NASA Astrophysics Data System (ADS)

Werner, K.; Knospe, A. G.; Markert, C.; Guiot, B.; Karpenko, Iu.; Pierog, T.; Sophys, G.; Stefaniak, M.; Bleicher, M.; Steinheimer, J.

2018-02-01

The aim of this paper is to understand resonance production (and more generally particle production) for different collision systems, namely proton-proton (pp), proton-nucleus (pA), and nucleus-nucleus (AA) scattering at the LHC. We will investigate in particular particle yields and ratios versus multiplicity, using the same multiplicity definition for the three different systems, in order to analyse in a compact way the evolution of particle production with the system size and the origin of a very different system size dependence of the different particles.

Pair production in classical Stueckelberg-Horwitz-Piron electrodynamics

NASA Astrophysics Data System (ADS)

Land, Martin

2015-05-01

We calculate pair production from bremsstrahlung as a classical effect in Stueckelberg-Horwitz electrodynamics. In this framework, worldlines are traced out dynamically through the evolution of events xμ(τ) parameterized by a chronological time τ that is independent of the spacetime coordinates. These events, defined in an unconstrained 8D phase space, interact through five τ-dependent gauge fields induced by the event evolution. The resulting theory differs in its underlying mechanics from conventional electromagnetism, but coincides with Maxwell theory in an equilibrium limit. In particular, the total mass-energy-momentum of particles and fields is conserved, but the mass-shell constraint is lifted from individual interacting events, so that the Feynman-Stueckelberg interpretation of pair creation/annihilation is implemented in classical mechanics. We consider a three-stage interaction which when parameterized by the laboratory clock x0 appears as (1) particle-1 scatters on a heavy nucleus to produce bremsstrahlung, (2) the radiation field produces a particle/antiparticle pair, (3) the antiparticle is annihilated with particle-2 in the presence of a second heavy nucleus. When parameterized in chronological time τ, the underlying process develops as (1) particle-2 scatters on the second nucleus and begins evolving backward in time with negative energy, (2) particle-1 scatters on the first nucleus and releases bremsstrahlung, (3) particle-2 absorbs radiation which returns it to forward time evolution with positive energy.

Computational Dynamics of Metal-Carbon Interface-- Key to Controllable Nanotube Growth

DTIC Science & Technology

2013-11-13

functionalization. 20, 21 On a finite- size particle , e.g., of radius R, the carbon nucleus has to accommodate mean curvature ~ 1/R by incorporating pentagonal...with diameter. Its length adjusting effect is not obvious at similar conditions. Yet as the precursor size increases, the bias energy also...enhance the effect of the force. Our mathematical abstraction may not precisely govern the behaviors of tubes that are not nucleated simultaneously or

Three-fold increase of M1 strength in 40Ar at 10 MeV excitation energy

NASA Astrophysics Data System (ADS)

Tornow, Werner; Finch, Sean; Krishichayan, Fnu; Tonchev, Anton

2017-09-01

We reexamined the excitation energy region of 40Ar around 9.8 MeV with the goal of determining the known M1 strength located at 9.76 MeV more accurately. The physics motivation was based on the fact that i) the neutrino-nucleus interaction cross section is proportional to the M1 strength of a nucleus, ii) DUNE, the Deep Underground Neutrino Experiment at SURF will be using liquid argon as detector medium, iii) the energy spectrum of supernova neutrinos is peaked at approximately 10 MeV. Mono-energetic and linearly polarized photons of 9.88 MeV were produced via Compton backscattering of 548 nm FEL photons from 543 MeV electrons at the High-Intensity γ-ray Source (HI γS) facility at TUNL. The 1.25 cm diameter photon beam with energy spread of 300 keV (FWHM) interacted with argon gas contained in a high-pressure cell. The cell was viewed with HPGe detectors placed at 90o relative to the incident photon beam in the horizontal and vertical planes to distinguish between E1 and M1 de-excitation γ-rays. Our re-measurement provided an increase in M1 strength by a factor of approximately 3, mostly due to the discovery that the known level in 40Ar at 9.84 MeV is of M1 character and not of E1 character, as previously thought. In addition to the already known M1 state at 9.76 MeV, we observed weaker M1 states at 9.70, 9.81, 9.87, and 9.89 MeV.

Fragmentation of Ar-40 at 100 GeV/c

NASA Technical Reports Server (NTRS)

Lindstrom, P. J.; Greiner, D. E.; Heckman, H. H.; Cork, B.; Bieser, F. S.

1975-01-01

The delta Z is greater than or equal to 1 reaction cross section for 1.8 GeV/n Ar-40 have been measured on targets ranging from H to Pb. Comparing these cross sections with H-1, C-12, and O-16 reaction cross sections at relativistic energies yields a formula for nucleus-nucleus reaction cross sections.

Experimental medium energy physics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barnes, P.D.

1991-01-01

This report discusses the following topics: Search for the H Dibaryon at the AGS; Hypernuclear Weak Decay Studies at the AGS; Relativistic Proton-Nucleus and Heavy Ion-Nucleus Collisions at the SPS; Hyperon-Antihyperon Production studies at LEAR; Hyperon Photoproduction at CEBAF; Double Lambda Hypernuclei; Weak Decay of Light Hypernuclei; and {pi}{sup 0}/{gamma}Detection with the CMU Scintillator Arrays.

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

NASA Technical Reports Server (NTRS)

Strugalski, Z.

1985-01-01

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

The Ionization Source in the Nucleus of M84

NASA Technical Reports Server (NTRS)

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

2000-01-01

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

Transverse momenta of fragments of relativistic sulfur and lead nuclei after their interaction with track-emulsion nuclei at energies of 200 and 160 GeV per nucleon

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lepekhin, F. G., E-mail: lepfed@yandex.ru; Tkach, L. N.

2011-05-15

Transverse-momentum distributions of doubly charged fragments of sulfur and lead nuclei having energies of 200 and 160 GeV per nucleon and interacting with nuclei in a track emulsion were investigated. No trace of compression or heating of nuclear matter in the interaction of these nuclei with track-emulsion nuclei was revealed experimentally. Transverse momenta of fragments of relativistic nuclei were found to obey a normal distribution that corresponds to a degenerate momentum distribution of nucleons in the ground state of a nucleus before its interaction with a track-emulsion nucleus. There is no piece of evidence that fragments of relativistic nuclei originatemore » from some excited state of an intermediate nucleus. This picture of the fragmentation of relativistic nuclei complies with the naive parton model proposed by Feynman and Gribov. In summary, the fragmentation of relativistic nuclei at energies of 160 and 200 GeV per nucleon is cold and fast.« less

Global optical model potential for A=3 projectiles

NASA Astrophysics Data System (ADS)

Pang, D. Y.; Roussel-Chomaz, P.; Savajols, H.; Varner, R. L.; Wolski, R.

2009-02-01

A global optical model potential (GDP08) for He3 projectiles has been obtained by simultaneously fitting the elastic scattering data of He3 from targets of 40⩽AT⩽209 at incident energies of 30⩽Einc⩽217 MeV. Uncertainties and correlation coefficients between the global potential parameters were obtained by using the bootstrap statistical method. GDP08 was found to satisfactorily account for the elastic scattering of H3 as well, which makes it a global optical potential for the A=3 nuclei. Optical model calculations using the GDP08 global potential are compared with the experimental angular distributions of differential cross sections for He3-nucleus and H3-nucleus scattering from different targets of 6⩽AT⩽232 at incident energies of 4⩽Einc⩽450 MeV. The optical potential for the doubly-magic nucleus Ca40, the low-energy correction to the real potential for nuclei with 58≲AT≲120 at Einc<30 MeV, the comparison with double-folding model calculations and the CH89 potential, and the spin-orbit potential parameters are discussed.

Optimization of exposure factors for X-ray radiography non-destructive testing of pearl oyster

NASA Astrophysics Data System (ADS)

Susilo; Yulianti, I.; Addawiyah, A.; Setiawan, R.

2018-03-01

One of the processes in pearl oyster cultivation is detecting the pearl nucleus to gain information whether the pearl nucleus is still attached in the shell or vomited. The common tool used to detect pearl nucleus is an X-ray machine. However, an X-ray machine has a drawback that is the energy used is higher than that used by digital radiography. The high energy make the resulted image is difficult to be analysed. One of the advantages of digital radiography is the energy used can be adjusted so that the resulted image can be analysed easily. To obtain a high quality of pearl image using digital radiography, the exposure factors should be optimized. In this work, optimization was done by varying the voltage, current, and exposure time. Then, the radiography images were analysed using Contrast to Noise Ratio (CNR). From the analysis, it can be determined that the optimum exposure factors are 60 kV of voltage, 16 mA of current, and 0.125 s of exposure time which result in CNR of 5.71.

The energy loss and nuclear absorption effects in semi-inclusive deep inelastic scattering on nucleus

NASA Astrophysics Data System (ADS)

Song, Li-Hua; Xin, Shang-Fei; Liu, Na

2018-02-01

Semi-inclusive deep inelastic lepton-nucleus scattering provides a good opportunity to investigate the cold nuclear effects on quark propagation and hadronization. Considering the nuclear modification of the quark energy loss and nuclear absorption effects in final state, the leading-order computations on hadron multiplicity ratios for both hadronization occurring outside and inside the medium are performed with the nuclear geometry effect of the path length L of the struck quark in the medium. By fitting the HERMES two-dimensional data on the multiplicity ratios for positively and negatively charged pions and kaons produced on neon, the hadron-nucleon inelastic cross section {σ }h for different identified hadrons is determined, respectively. It is found that our predictions obtained with the analytic parameterizations of quenching weights based on BDMPS formalism and the nuclear absorption factor {N}A(z,ν ) are in good agreement with the experimental measurements. This indicates that the energy loss and nuclear absorption are the main nuclear effects inducing a reduction of the hadron yield for quark hadronization occurring outside and inside the nucleus, respectively.

Unusual Crystallization Behavior Close to the Glass Transition

NASA Astrophysics Data System (ADS)

Desgranges, Caroline; Delhommelle, Jerome

2018-03-01

Using molecular simulations, we shed light on the mechanism underlying crystal nucleation in metal alloys and unravel the interplay between crystal nucleation and glass transition, as the conditions of crystallization lie close to this transition. While decreasing the temperature of crystallization usually results in a lower free energy barrier, we find an unexpected reversal of behavior for glass-forming alloys as the temperature of crystallization approaches the glass transition. For this purpose, we simulate the crystallization process in two glass-forming Copper alloys, Ag6 Cu4 , which has a positive heat of mixing, and CuZr, characterized by a large negative heat of mixing. Our results allow us to identify this unusual behavior as directly correlated with a nonmonotonic temperature dependence for the formation energy of connected icosahedral structures, which are incompatible with crystalline order and impede the development of the crystal nucleus, leading to an unexpectedly larger free energy barrier at low temperature. This, in turn, promotes the formation of a predominantly closed-packed critical nucleus, with fewer defects, thereby suggesting a new way to control the structure of the crystal nucleus, which is of key importance in catalysis.

Analysis of variances of quasirapidities in collisions of gold nuclei with track-emulsion nuclei

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gulamov, K. G.; Zhokhova, S. I.; Lugovoi, V. V., E-mail: lugovoi@uzsci.net

2012-08-15

A new method of an analysis of variances was developed for studying n-particle correlations of quasirapidities in nucleus-nucleus collisions for a large constant number n of particles. Formulas that generalize the results of the respective analysis to various values of n were derived. Calculations on the basis of simple models indicate that the method is applicable, at least for n {>=} 100. Quasirapidity correlations statistically significant at a level of 36 standard deviations were discovered in collisions between gold nuclei and track-emulsion nuclei at an energy of 10.6 GeV per nucleon. The experimental data obtained in our present study aremore » contrasted against the theory of nucleus-nucleus collisions.« less

New aspects in nucleon-nucleus collisions and EAS properties around 10(6) GeV

NASA Technical Reports Server (NTRS)

Capdevielle, J. N.; Gawin, J.

1985-01-01

At energies higher than 2 x 10 to the 5 GeV, very little information exists on detailed properties of nucleon-nucleon collision; the rare elements are coming from jets, and, as nondirect improvements from gamma-ray families. The results exhibit some conflicting features, or, at least, very large fluctuations like copious production of gamma-rays in opposition to Centauro-like events, sometimes suggest that phase transition to quark gluon plasma occurs in nucleus-nucleus collisions and even in nucleon-nucleus collision. The multicluster phenomenological model (MPM) extrapolated for extensive air showers EAS simulation up to 5 x 10 to the 6 GeV to put in evidence some significant deviation between experimental data and prediction.

Positive parity low spin states of odd-mass tellurium isotopes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yazar, Harun Resit

2006-11-15

In this work, we analyse the positive parity of states of odd-mass nucleus within the framework of interacting boson fermion model. The result of an IBFM-1 multilevel calculation with the lg{sub 9/2}, 2d{sub 5/2}, 2d{sub 3/2}, 3s{sub 1/2} and one level, 1h{sub 11/2} with negative parity, single particle orbits is reported for the positive parity states of the odd mass nucleus {sup 123-125}Te. Also, an IBM-1 calculation is presented for the low-lying states in the even-even {sup 124-126}Te core nucleus. The energy levels and B (E2) transition probabilities were calculated and compared with the experimental data. It was found thatmore » the calculated positive parity low spin state energy spectra of the odd-mass {sup 123-125}Te isotopes agree quite well with the experimental data.« less

Nuclear surface diffuseness revealed in nucleon-nucleus diffraction

NASA Astrophysics Data System (ADS)

Hatakeyama, S.; Horiuchi, W.; Kohama, A.

2018-05-01

The nuclear surface provides useful information on nuclear radius, nuclear structure, as well as properties of nuclear matter. We discuss the relationship between the nuclear surface diffuseness and elastic scattering differential cross section at the first diffraction peak of high-energy nucleon-nucleus scattering as an efficient tool in order to extract the nuclear surface information from limited experimental data involving short-lived unstable nuclei. The high-energy reaction is described by a reliable microscopic reaction theory, the Glauber model. Extending the idea of the black sphere model, we find one-to-one correspondence between the nuclear bulk structure information and proton-nucleus elastic scattering diffraction peak. This implies that we can extract both the nuclear radius and diffuseness simultaneously, using the position of the first diffraction peak and its magnitude of the elastic scattering differential cross section. We confirm the reliability of this approach by using realistic density distributions obtained by a mean-field model.

Elastic Differential Cross Sections

NASA Technical Reports Server (NTRS)

Werneth, Charles M.; Maung, Khin M.; Ford, William P.; Norbury, John W.; Vera, Michael D.

2014-01-01

The eikonal, partial wave (PW) Lippmann-Schwinger, and three-dimensional Lippmann-Schwinger (LS3D) methods are compared for nuclear reactions that are relevant for space radiation applications. Numerical convergence of the eikonal method is readily achieved when exact formulas of the optical potential are used for light nuclei (A less than or equal to 16) and the momentum-space optical potential is used for heavier nuclei. The PW solution method is known to be numerically unstable for systems that require a large number of partial waves, and, as a result, the LS3D method is employed. The effect of relativistic kinematics is studied with the PW and LS3D methods and is compared to eikonal results. It is recommended that the LS3D method be used for high energy nucleon- nucleus reactions and nucleus-nucleus reactions at all energies because of its rapid numerical convergence and stability.

Nuclear Cross Sections for Space Radiation Applications

NASA Technical Reports Server (NTRS)

Werneth, C. M.; Maung, K. M.; Ford, W. P.; Norbury, J. W.; Vera, M. D.

2015-01-01

The eikonal, partial wave (PW) Lippmann-Schwinger, and three-dimensional Lippmann-Schwinger (LS3D) methods are compared for nuclear reactions that are relevant for space radiation applications. Numerical convergence of the eikonal method is readily achieved when exact formulas of the optical potential are used for light nuclei (A = 16) and the momentum-space optical potential is used for heavier nuclei. The PW solution method is known to be numerically unstable for systems that require a large number of partial waves, and, as a result, the LS3D method is employed. The effect of relativistic kinematics is studied with the PW and LS3D methods and is compared to eikonal results. It is recommended that the LS3D method be used for high energy nucleon-nucleus reactions and nucleus-nucleus reactions at all energies because of its rapid numerical convergence and stability for both non-relativistic and relativistic kinematics.

Quantitative immuno-electron microscopic analysis of depolarization-induced expression of PGC-1alpha in cultured rat visual cortical neurons.

PubMed

Meng, Hui; Liang, Huan Ling; Wong-Riley, Margaret

2007-10-17

Peroxisome proliferator-activated receptor-gamma coactivator 1alpha (PGC- 1alpha) is a coactivator of nuclear receptors and other transcription factors that regulate several metabolic processes, including mitochondrial biogenesis, energy homeostasis, respiration, and gluconeogenesis. PGC-1alpha plays a vital role in stimulating genes that are important to oxidative metabolism and other mitochondrial functions in brown adipose tissue and skeleton muscles, but the significance of PGC-1alpha in the brain remains elusive. The goal of our present study was to determine by means of quantitative immuno-electron microscopy the expression of PGC-1alpha in cultured rat visual cortical neurons under normal conditions as well as after depolarizing stimulation for varying periods of time. Our results showed that: (a) PGC-1alpha was normally located in both the nucleus and the cytoplasm. In the nucleus, PGC-1alpha was associated mainly with euchromatin rather than heterochromatin, consistent with active involvement in transcription. In the cytoplasm, it was associated mainly with free ribosomes. (b) Neuronal depolarization by KCl for 0.5 h induced a significant increase in PGC-1alpha labeling density in both the nucleus and the cytoplasm (P<0.01). The heightened expression continued after 1 and 3 h of depolarizing treatment (P<0.01), but decreased from 5 h onward and returned to baseline level by 10 h. These results indicate that PGC-1alpha responds very early to increased neuronal activity by synthesizing more proteins in the cytoplasm and translocating them to the nucleus for gene activation. PGC-1alpha level in neurons is, therefore, tightly regulated by neuronal activity.

Fission fragment mass distributions from 210Po and 213At

NASA Astrophysics Data System (ADS)

Sen, A.; Ghosh, T. K.; Bhattacharya, S.; Banerjee, K.; Bhattacharya, C.; Kundu, S.; Mukherjee, G.; Asgar, A.; Dey, A.; Dhal, A.; Shaikh, Md. Moin; Meena, J. K.; Manna, S.; Pandey, R.; Rana, T. K.; Roy, Pratap; Roy, T.; Srivastava, V.; Bhattacharya, P.

2017-12-01

Background: The influence of shell effect on the dynamics of the fusion fission process and its evolution with excitation energy in the preactinide Hg-Pb region in general is a matter of intense research in recent years. In particular, a strong ambiguity remains for the neutron shell closed 210Po nucleus regarding the role of shell effect in fission around ≈30 -40 MeV of excitation energy. Purpose: We have measured the fission fragment mass distribution of 210Po populated using fusion of 4He+206Pb at different excitation energies and compare the result with recent theoretical predictions as well as with our previous measurement for the same nucleus populated through a different entrance channel. Mass distribution in the fission of the neighboring nuclei 213At is also studied for comparison. Methods: Two large area multiwire proportional counters (MWPC) were used for complete kinematical measurement of the coincident fission fragments. The time of flight differences of the coincident fission fragments were used to directly extract the fission fragment mass distributions. Results: The measured fragment mass distribution for the reactions 4He+206Pb and 4He+209Bi were symmetric and the width of the mass distributions were found to increase monotonically with excitation energy above 36.7 MeV and 32.9 MeV, respectively, indicating the absence of shell effects at the saddle. However, in the fission of 210Po, we find minor deviation from symmetric mass distributions at the lowest excitation energy (30.8 MeV). Conclusion: Persistence of shell effect in fission fragment mass distribution of 210Po was observed at the excitation energy ≈31 MeV as predicted by the theory; at higher excitation energy, however, the present study reaffirms the absence of any shell correction in the fission of 210Po.

Neuroanatomy of melanocortin-4 receptor pathway in the lateral hypothalamic area.

PubMed

Cui, Huxing; Sohn, Jong-Woo; Gautron, Laurent; Funahashi, Hisayuki; Williams, Kevin W; Elmquist, Joel K; Lutter, Michael

2012-12-15

The central melanocortin system regulates body energy homeostasis including the melanocortin-4 receptor (MC4R). The lateral hypothalamic area (LHA) receives dense melanocortinergic inputs from the arcuate nucleus of the hypothalamus and regulates multiple processes including food intake, reward behaviors, and autonomic function. By using a mouse line in which green fluorescent protein (GFP) is expressed under control of the MC4R gene promoter, we systemically investigated MC4R signaling in the LHA by combining double immunohistochemistry, electrophysiology, and retrograde tracing techniques. We found that LHA MC4R-GFP neurons coexpress neurotensin as well as the leptin receptor but do not coexpress other peptide neurotransmitters found in the LHA including orexin, melanin-concentrating hormone, and nesfatin-1. Furthermore, electrophysiological recording demonstrated that leptin, but not the MC4R agonist melanotan II, hyperpolarizes the majority of LHA MC4R-GFP neurons in an ATP- sensitive potassium channel-dependent manner. Retrograde tracing revealed that LHA MC4R-GFP neurons do not project to the ventral tegmental area, dorsal raphe nucleus, nucleus accumbens, and spinal cord, and only limited number of neurons project to the nucleus of the solitary tract and parabrachial nucleus. Our findings provide new insights into MC4R signaling in the LHA and its potential implications in homeostatic regulation of body energy balance. Copyright © 2012 Wiley Periodicals, Inc.

Touch-Initiated Reaction of Nitrogen Triiodide as a Template for Activation Energy Classroom Discussions

ERIC Educational Resources Information Center

Short, Duncan

2017-01-01

Activation energies form an energy barrier to a chemical reaction taking place. Simple collision theory, i.e. that particles need to collide to react, would suggest that activation energy is the energy needed to overcome a coulombic barrier provided by the negatively charged electrons contained within energy shells surrounding an atomic nucleus.…

Experimental study of the β decay of the very neutron-rich nucleus Ge 85

DOE PAGES

Korgul, A.; Rykaczewski, Krzysztof Piotr; Grzywacz, Robert Kazimierz; ...

2017-04-04

The β -decay properties of the very neutron-rich nucleus 85Ge, produced in the proton-induced fission of 238U, were studied at the Holifield Radioactive Ion Beam Facility at Oak Ridge National Laboratory. The level scheme of 33 85As 52 populated in 85Geβ γ decay was reconstructed and compared to shell-model calculations. The investigation of the systematics of low-energy levels in N =52 isotones together with shell-model analysis allowed us to provide an estimate of the low-energy structure of the more exotic N =52 isotone 81Cu.

Thomas-Fermi simulations of dense plasmas without pseudopotentials

NASA Astrophysics Data System (ADS)

Starrett, C. E.

2017-07-01

The Thomas-Fermi model for warm and hot dense matter is widely used to predict material properties such as the equation of state. However, for practical reasons current implementations use pseudopotentials for the electron-nucleus interaction instead of the bare Coulomb potential. This complicates the calculation and quantities such as free energy cannot be converged with respect to the pseudopotential parameters. We present a method that retains the bare Coulomb potential for the electron-nucleus interaction and does not use pseudopotentials. We demonstrate that accurate free energies are obtained by checking variational consistency. Examples for aluminum and iron plasmas are presented.

An energy-dependent numerical model for the condensation probability, γ j

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kerby, Leslie Marie

The “condensation” probability, γ j, is an important variable in the preequilibrium stage of nuclear spallation reactions. It represents the probability that p j excited nucleons (excitons) will “condense” to form complex particle type j in the excited residual nucleus. In addition, it has a significant impact on the emission width, or probability of emitting fragment type j from the residual nucleus. Previous formulations for γ j were energy-independent and valid for fragments up to 4He only. This paper explores the formulation of a new model for γ j, one which is energy-dependent and valid for up to 28Mg, andmore » which provides improved fits compared to experimental fragment spectra.« less

Hydrodynamic description for the pseudorapidity distributions of the charged particles produced in nucleus+nucleus collisions at high energy

NASA Astrophysics Data System (ADS)

Zhang, Haili; Jiang, Zhijin; Li, Qingguang; Jiang, Guanxiang

2014-02-01

By using the revised Landau hydrodynamic model and taking into account the effect of leading particles, we discuss the pseudorapidity distributions of the charged particles produced in high-energy heavy-ion collisions. The leading particles are assumed to have the rapidity distributions with Gaussian forms with the normalization constant being equal to the number of participants, which can be figured out in theory. The results from the revised Landau hydrodynamic model, together with the contributions from leading particles, were found to be consistent with the experimental data obtained by the PHOBOS Collaboration on RHIC (Relativistic Heavy Ion Collider) at BNL (Brookhaven National Laboratory) in different centrality Cu+Cu and Au+Au collisions at high energies.

An energy-dependent numerical model for the condensation probability, γ j

DOE PAGES

Kerby, Leslie Marie

2016-12-09

The “condensation” probability, γ j, is an important variable in the preequilibrium stage of nuclear spallation reactions. It represents the probability that p j excited nucleons (excitons) will “condense” to form complex particle type j in the excited residual nucleus. In addition, it has a significant impact on the emission width, or probability of emitting fragment type j from the residual nucleus. Previous formulations for γ j were energy-independent and valid for fragments up to 4He only. This paper explores the formulation of a new model for γ j, one which is energy-dependent and valid for up to 28Mg, andmore » which provides improved fits compared to experimental fragment spectra.« less

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brice, S. J.; Cooper, R. L.; DeJongh, F.

2014-04-03

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

First Measurement of Monoenergetic Muon Neutrino Charged Current Interactions

NASA Astrophysics Data System (ADS)

Aguilar-Arevalo, A. A.; Brown, B. C.; Bugel, L.; Cheng, G.; Church, E. D.; Conrad, J. M.; Cooper, R. L.; Dharmapalan, R.; Djurcic, Z.; Finley, D. A.; Fitzpatrick, R. S.; Ford, R.; Garcia, F. G.; Garvey, G. T.; Grange, J.; Huelsnitz, W.; Ignarra, C.; Imlay, R.; Johnson, R. A.; Jordan, J. R.; Karagiorgi, G.; Katori, T.; Kobilarcik, T.; Louis, W. C.; Mahn, K.; Mariani, C.; Marsh, W.; Mills, G. B.; Mirabal, J.; Moore, C. D.; Mousseau, J.; Nienaber, P.; Osmanov, B.; Pavlovic, Z.; Perevalov, D.; Ray, H.; Roe, B. P.; Russell, A. D.; Shaevitz, M. H.; Spitz, J.; Stancu, I.; Tayloe, R.; Thornton, R. T.; Van de Water, R. G.; Wascko, M. O.; White, D. H.; Wickremasinghe, D. A.; Zeller, G. P.; Zimmerman, E. D.; MiniBooNE Collaboration

2018-04-01

We report the first measurement of monoenergetic muon neutrino charged current interactions. MiniBooNE has isolated 236 MeV muon neutrino events originating from charged kaon decay at rest (K+→μ+νμ) at the NuMI beamline absorber. These signal νμ -carbon events are distinguished from primarily pion decay in flight νμ and ν¯μ backgrounds produced at the target station and decay pipe using their arrival time and reconstructed muon energy. The significance of the signal observation is at the 3.9 σ level. The muon kinetic energy, neutrino-nucleus energy transfer (ω =Eν-Eμ), and total cross section for these events are extracted. This result is the first known-energy, weak-interaction-only probe of the nucleus to yield a measurement of ω using neutrinos, a quantity thus far only accessible through electron scattering.

Voluntary exercise improves high-fat diet-induced leptin resistance independent of adiposity.

PubMed

Krawczewski Carhuatanta, Kimberly A; Demuro, Giovanna; Tschöp, Matthias H; Pfluger, Paul T; Benoit, Stephen C; Obici, Silvana

2011-07-01

The efficacy of exercise as primary prevention of obesity is the subject of intense investigation. Here, we show that voluntary exercise in a mouse strain susceptible to diet-induced obesity (C57B6J) decreases fat mass and increases energy expenditure. In addition, exercise attenuates obesity in mice fed a high-fat diet (HFD). Using FosB immunoreactivity as a marker of chronic neuronal activation, we found that exercise activates leptin receptor-positive neurons in the ventromedial hypothalamic nucleus, involved in homeostatic control of energy balance. FosB immunoreactivity in the ventromedial hypothalamic nucleus is decreased in sedentary mice exposed to HFD but is increased in exercised mice independent of adiposity. To determine whether the antiobesity effects of voluntary exercise improve central nervous system (CNS) leptin action, we measured the anorectic and weight reducing effects of intracerebroventricular (ICV) leptin in sedentary and exercised mice exposed to HFD (EH), as well as in sedentary mice that have been calorie restricted (SR) to match the fat mass of EH mice. ICV leptin was ineffective in lowering food intake and body weight (BW) in sedentary mice exposed to HFD mice. The anorectic potency of leptin was partially restored in EH and SR groups. However, ICV leptin significantly lowered BW in EH but not SR mice. Thus, exercise leads to the maintenance of a lower BW and leaner composition, as well as to improved CNS leptin action, independent of fat mass. These results support the notion that physical exercise directly influences the responsiveness of the CNS circuits involved in energy homeostasis by allowing the defense of a lowered BW.

Capture of a neutron to excited states of a {sup 9}Be nucleus taking into account resonance at 622 keV

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dubovichenko, S. B., E-mail: dubovichenko@gmail.com

2013-10-15

Radiative capture of a neutron to the ground and excited states of the 9Be nucleus is considered using the potential cluster model with forbidden states and with classification of cluster states by the Young schemes taking into account resonance at 622 keV for thermal and astrophysical energies.

Lifetime measurements in shape transition nucleus 188Pt

NASA Astrophysics Data System (ADS)

Rohilla, Aman; Gupta, C. K.; Singh, R. P.; Muralithar, S.; Chakraborty, S.; Sharma, H. P.; Kumar, A.; Govil, I. M.; Biswas, D. C.; Chamoli, S. K.

2017-04-01

Nuclear level lifetimes of high spin states in yrast and non-yrast bands of 188Pt nucleus have been measured using recoil distance plunger setup present at IUAC, Delhi. In the experiment nuclear states of interest were populated via 174Yb(18O,4 n)188Pt reaction at a beam energy of 79MeV provided by 15 UD Pelletron accelerator. The extracted B(E2\\downarrow) values show an initial rise up to 4+ state and then a nearly constant behavior with spin along yrast band, indicating change of nuclear structure in 188Pt at low spins. The good agreement between experimental and TPSM model B(E2\\downarrow) values up to 4^+ state suggests an increase in axial deformation of the nucleus. The average absolute β2 = 0.20 (3) obtained from measured B(E2\\downarrow) values matches well the values predicted by CHFB and IBM calculations for oblate ( β2 ˜ -0.19) and prolate (β2 ˜ 0.22) shapes. As the lifetime measurements do not yield the sign of β2, no definite conclusion can be drawn on the prolate or oblate collectivity of 188Pt on the basis of present measurements.

Single-particle excitations in the level structure of 64Cu

NASA Astrophysics Data System (ADS)

Samanta, S.; Das, S.; Bhattacharjee, R.; Chatterjee, S.; Raut, R.; Ghugre, S. S.; Sinha, A. K.; Garg, U.; Neelam, Kumar, N.; Jones, P.; Laskar, Md. Sazedur R.; Babra, F. S.; Biswas, S.; Saha, S.; Singh, P.; Palit, R.

2018-01-01

Excited states of the 64Cu(Z =29 ,N =35 ) nucleus have been probed using heavy-ion-induced fusion evaporation reaction and an array of Compton-suppressed Clovers as detection system for the emitted γ rays. More than 50 new transitions have been identified and the level scheme of the nucleus has been established up to an excitation energy Ex˜6 MeV and spin ˜10 ℏ . The experimental results have been compared with those from large-basis shell-model calculations that facilitated an understanding of the single-particle configurations underlying the level structure of the nucleus.

Gastrointestinal hormones regulating appetite

PubMed Central

Chaudhri, Owais; Small, Caroline; Bloom, Steve

2006-01-01

The role of gastrointestinal hormones in the regulation of appetite is reviewed. The gastrointestinal tract is the largest endocrine organ in the body. Gut hormones function to optimize the process of digestion and absorption of nutrients by the gut. In this capacity, their local effects on gastrointestinal motility and secretion have been well characterized. By altering the rate at which nutrients are delivered to compartments of the alimentary canal, the control of food intake arguably constitutes another point at which intervention may promote efficient digestion and nutrient uptake. In recent decades, gut hormones have come to occupy a central place in the complex neuroendocrine interactions that underlie the regulation of energy balance. Many gut peptides have been shown to influence energy intake. The most well studied in this regard are cholecystokinin (CCK), pancreatic polypeptide, peptide YY, glucagon-like peptide-1 (GLP-1), oxyntomodulin and ghrelin. With the exception of ghrelin, these hormones act to increase satiety and decrease food intake. The mechanisms by which gut hormones modify feeding are the subject of ongoing investigation. Local effects such as the inhibition of gastric emptying might contribute to the decrease in energy intake. Activation of mechanoreceptors as a result of gastric distension may inhibit further food intake via neural reflex arcs. Circulating gut hormones have also been shown to act directly on neurons in hypothalamic and brainstem centres of appetite control. The median eminence and area postrema are characterized by a deficiency of the blood–brain barrier. Some investigators argue that this renders neighbouring structures, such as the arcuate nucleus of the hypothalamus and the nucleus of the tractus solitarius in the brainstem, susceptible to influence by circulating factors. Extensive reciprocal connections exist between these areas and the hypothalamic paraventricular nucleus and other energy-regulating centres of the central nervous system. In this way, hormonal signals from the gut may be translated into the subjective sensation of satiety. Moreover, the importance of the brain–gut axis in the control of food intake is reflected in the dual role exhibited by many gut peptides as both hormones and neurotransmitters. Peptides such as CCK and GLP-1 are expressed in neurons projecting both into and out of areas of the central nervous system critical to energy balance. The global increase in the incidence of obesity and the associated burden of morbidity has imparted greater urgency to understanding the processes of appetite control. Appetite regulation offers an integrated model of a brain–gut axis comprising both endocrine and neurological systems. As physiological mediators of satiety, gut hormones offer an attractive therapeutic target in the treatment of obesity. PMID:16815798

Solid liquid interfacial free energies of benzene

NASA Astrophysics Data System (ADS)

Azreg-Aı¨nou, M.

2007-02-01

In this work we determine for the range of melting temperatures 284.6⩽T⩽306.7 K, corresponding to equilibrium pressures 20.6⩽P⩽102.9 MPa, the benzene solid-liquid interfacial free energy by a cognitive approach including theoretical and experimental physics, mathematics, computer algebra (MATLAB), and some results from molecular dynamics computer simulations. From a theoretical and mathematical points of view, we deal with the elaboration of an analytical expression for the internal energy derived from a unified solid-liquid-vapor equation of state and with the elaboration of an existing statistical model for the entropy drop of the melt near the solid-liquid interface. From an experimental point of view, we will use our results obtained in collaboration with colleagues concerning the supercooled liquid benzene. Of particular interest for this work is the existing center-of-mass radial distribution function of benzene at 298 K obtained by computer simulation. Crystal-orientation-independent and minimum interfacial free energies are calculated and shown to increase slightly with the above temperatures. Both crystal-orientation-independent and minimum free energies agree with existing calculations and with rare existing experimental data. Taking into account the fact that the extent of supercooling is generally admitted as a constant, we determine the limits of supercooling by which we explore the behavior of the critical nucleus radius which is shown to decrease in terms of the above temperatures. The radius of the, and the number of molecules per, critical nucleus are shown to assume the average values of 20.2 A˚ and 175 with standard deviations of 0.16 Å and 4.5, respectively.

Nuclear structure research at the Triangle Universities Nuclear Laboratory

NASA Astrophysics Data System (ADS)

Mitchell, G. E.

1992-10-01

Studies of fundamental symmetries by the TRIPLE collaboration using the unique capabilities at LAMTF have found unexpected systematics in the parity-violating amplitudes for epithermal-neutron scattering. Tests to lower the present limits on time-reversal-invariance violation in the strong interaction are being made at in experiments on the scattering of polarized fast neutrons from aligned holmium targets. Studies of few-nucleon systems have received increasing emphasis over the past year, involving a broad program for testing the low- to medium-energy internucleon interactions, from the tensor component in n-p scattering and the n-n scattering lengths, through three-nucleon systems and the alpha particle, on up to Be-8. Of particular interest are three-nucleon systems, both in elastic scattering and in three-body breakup. Beam requirements range from production of intense and highly-polarized neutron beams to tensor-polarized beams for measurements at both very low energies (25-80 keV) and at tandem energies for definitive measurements of D-state components of the triton, He-3, and He-4 obtained from transfer reactions. The program in nuclear astrophysics expanded during 1991-1992. Several facets of the nuclear many-body problem and of excitation mechanisms of the nucleus are being elucidated, including measurements and analyses to elucidate the neutron-nucleus elastic-scattering interaction over a wide range of nuclei and energies. Several projects involved developments in electronuclear physics, instrumentation, RF-transition units, and low-temperature bolometric particle detectors.

Treatment with tianeptine induces antidepressive-like effects and alters the neurotrophin levels, mitochondrial respiratory chain and cycle Krebs enzymes in the brain of maternally deprived adult rats.

PubMed

Della, Franciela P; Abelaira, Helena M; Réus, Gislaine Z; Santos, Maria Augusta B dos; Tomaz, Débora B; Antunes, Altamir R; Scaini, Giselli; Morais, Meline O S; Streck, Emilio L; Quevedo, João

2013-03-01

Maternally deprived rats were treated with tianeptine (15 mg/kg) once a day for 14 days during their adult phase. Their behavior was then assessed using the forced swimming and open field tests. The BDNF, NGF and energy metabolism were assessed in the rat brain. Deprived rats increased the immobility time, but tianeptine reversed this effect and increased the swimming time; the BDNF levels were decreased in the amygdala of the deprived rats treated with saline and the BDNF levels were decreased in the nucleus accumbens within all groups; the NGF was found to have decreased in the hippocampus, amygdala and nucleus accumbens of the deprived rats; citrate synthase was increased in the hippocampus of non-deprived rats treated with tianeptine and the creatine kinase was decreased in the hippocampus and amygdala of the deprived rats; the mitochondrial complex I and II-III were inhibited, and tianeptine increased the mitochondrial complex II and IV in the hippocampus of the non-deprived rats; the succinate dehydrogenase was increased in the hippocampus of non-deprived rats treated with tianeptine. So, tianeptine showed antidepressant effects conducted on maternally deprived rats, and this can be attributed to its action on the neurochemical pathways related to depression.

α -induced reactions on 115In: Cross section measurements and statistical model analysis

NASA Astrophysics Data System (ADS)

Kiss, G. G.; Szücs, T.; Mohr, P.; Török, Zs.; Huszánk, R.; Gyürky, Gy.; Fülöp, Zs.

2018-05-01

Background: α -nucleus optical potentials are basic ingredients of statistical model calculations used in nucleosynthesis simulations. While the nucleon+nucleus optical potential is fairly well known, for the α +nucleus optical potential several different parameter sets exist and large deviations, reaching sometimes even an order of magnitude, are found between the cross section predictions calculated using different parameter sets. Purpose: A measurement of the radiative α -capture and the α -induced reaction cross sections on the nucleus 115In at low energies allows a stringent test of statistical model predictions. Since experimental data are scarce in this mass region, this measurement can be an important input to test the global applicability of α +nucleus optical model potentials and further ingredients of the statistical model. Methods: The reaction cross sections were measured by means of the activation method. The produced activities were determined by off-line detection of the γ rays and characteristic x rays emitted during the electron capture decay of the produced Sb isotopes. The 115In(α ,γ )119Sb and 115In(α ,n )Sb118m reaction cross sections were measured between Ec .m .=8.83 and 15.58 MeV, and the 115In(α ,n )Sb118g reaction was studied between Ec .m .=11.10 and 15.58 MeV. The theoretical analysis was performed within the statistical model. Results: The simultaneous measurement of the (α ,γ ) and (α ,n ) cross sections allowed us to determine a best-fit combination of all parameters for the statistical model. The α +nucleus optical potential is identified as the most important input for the statistical model. The best fit is obtained for the new Atomki-V1 potential, and good reproduction of the experimental data is also achieved for the first version of the Demetriou potentials and the simple McFadden-Satchler potential. The nucleon optical potential, the γ -ray strength function, and the level density parametrization are also constrained by the data although there is no unique best-fit combination. Conclusions: The best-fit calculations allow us to extrapolate the low-energy (α ,γ ) cross section of 115In to the astrophysical Gamow window with reasonable uncertainties. However, still further improvements of the α -nucleus potential are required for a global description of elastic (α ,α ) scattering and α -induced reactions in a wide range of masses and energies.

α-cluster versus non-α-cluster decay of the excited compound nucleus Ce124* using the dynamical cluster-decay model

NASA Astrophysics Data System (ADS)

Kaur, Arshdeep; Chopra, Sahila; Gupta, Raj K.

2014-03-01

The dynamical cluster-decay model (DCM), an extended version of the preformed cluster model (PCM) for ground-state (T =0) decays, is applied to study the decay of the proton-rich compound nucleus Ce124* formed in the S32 + Mo92 reaction at an above-barrier beam energy of 150 MeV. Application of the statistical code pace4 to experimental data shows large deviations in all cases of proton clusters' (2p, 3p, and 4p) evaporation residue (ER) and the non-α nucleus Be6 intermediate mass fragment (IMF). Furthermore, the α-nucleus Be8 decay is not observed in this experiment (not even the upper limit is given). Using the DCM, with effects of deformations up to hexadecapole and "compact" orientations included, for the best-fitted cross sections of 2p and 3p ERs and of Li5 and Be6 IMFs, the relative cross section of Be8 is found to be more than that of Be6, possibly due to the α-nucleus structure of Be8. The same is shown to be true for C12 versus C10, i.e., α-nuclei clusters are populated strongly relative to non-α clusters, similar to what was predicted by one of us (R.K.G.) et al. [S. Kumar, D. Bir, and R. K. Gupta, Phys. Rev. C 51, 1762 (1995), 10.1103/PhysRevC.51.1762] for ground-state decays of such nuclei and the decay of Ba116* formed in the Ni58 + Ni58 reaction at various compound nucleus excitation energies [R. K. Gupta et al., J. Phys. G: Nucl. Part. Phys. 32, 345 (2006), 10.1088/0954-3899/32/3/009]. The only parameter of the DCM is the neck-length ΔR, related to the "barrier-lowering" parameter. The compound nucleus formation probability and "barrier-lowering/-modification" effects are analyzed, and the role of varying the deformations of Be6 and/or Be8 nuclei on relative cross sections is studied, since the measured deformations are not available. The ones used here are from relativistic mean-field calculations [β2(6Be )=-0.087 and β2(8Be)=-0.094]. Calculations are also presented for a beam energy of 140 MeV, supporting the above result.

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

PubMed

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

2013-07-01

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

An Intact Dorsomedial Posterior Arcuate Nucleus is Not Necessary for Photoperiodic Responses in Siberian Hamsters1

PubMed Central

Teubner, Brett J.W.; Leitner, Claudia; Thomas, Michael A.; Ryu, Vitaly; Bartness, Timothy J.

2015-01-01

Seasonal responses of many animal species are triggered by changes in daylength and its transduction into a neuroendocrine signal by the pineal gland through the nocturnal duration of melatonin (MEL) release. The precise central sites necessary to receive, transduce, and relay the short day (SD) fall-winter MEL signals into seasonal responses and changes in physiology and behavior are unclear. In Siberian hamsters, SDs trigger decreases in body and lipid mass, testicular regression and pelage color changes. Several candidate genes and their central sites of expression have been proposed as components of the MEL transduction system with considerable recent focus on the arcuate nucleus (ARC) and its component, the dorsomedial posterior arcuate nucleus (dmpARC). This site has been postulated as a critical relay of SD information through the modulation of a variety of neurochemicals/receptors important for the control of energy balance. Here the necessity of an intact dmpARC for SD responses was tested by making electrolytic lesions of the Siberian hamster dmpARC and then exposing them to either long days (LD) or SDs for 12 weeks. The SD typical decreases in body and fat mass, food intake, testicular volume, serum testosterone concentrations, pelage color change and increased UCP-1 protein expression (a proxy for brown adipose tissue thermogenesis) all occurred despite the lack of an intact dmpARC. Although the Siberian hamster dmpARC contains photoperiod-modulated constituents, these data demonstrate that an intact dmpARC is not necessary for SD responses and not integral to the seasonal energy- and reproductive-related responses measured here. PMID:25647158

The human subthalamic nucleus encodes the subjective value of reward and the cost of effort during decision-making.

PubMed

Zénon, Alexandre; Duclos, Yann; Carron, Romain; Witjas, Tatiana; Baunez, Christelle; Régis, Jean; Azulay, Jean-Philippe; Brown, Peter; Eusebio, Alexandre

2016-06-01

Adaptive behaviour entails the capacity to select actions as a function of their energy cost and expected value and the disruption of this faculty is now viewed as a possible cause of the symptoms of Parkinson's disease. Indirect evidence points to the involvement of the subthalamic nucleus-the most common target for deep brain stimulation in Parkinson's disease-in cost-benefit computation. However, this putative function appears at odds with the current view that the subthalamic nucleus is important for adjusting behaviour to conflict. Here we tested these contrasting hypotheses by recording the neuronal activity of the subthalamic nucleus of patients with Parkinson's disease during an effort-based decision task. Local field potentials were recorded from the subthalamic nucleus of 12 patients with advanced Parkinson's disease (mean age 63.8 years ± 6.8; mean disease duration 9.4 years ± 2.5) both OFF and ON levodopa while they had to decide whether to engage in an effort task based on the level of effort required and the value of the reward promised in return. The data were analysed using generalized linear mixed models and cluster-based permutation methods. Behaviourally, the probability of trial acceptance increased with the reward value and decreased with the required effort level. Dopamine replacement therapy increased the rate of acceptance for efforts associated with low rewards. When recording the subthalamic nucleus activity, we found a clear neural response to both reward and effort cues in the 1-10 Hz range. In addition these responses were informative of the subjective value of reward and level of effort rather than their actual quantities, such that they were predictive of the participant's decisions. OFF levodopa, this link with acceptance was weakened. Finally, we found that these responses did not index conflict, as they did not vary as a function of the distance from indifference in the acceptance decision. These findings show that low-frequency neuronal activity in the subthalamic nucleus may encode the information required to make cost-benefit comparisons, rather than signal conflict. The link between these neural responses and behaviour was stronger under dopamine replacement therapy. Our findings are consistent with the view that Parkinson's disease symptoms may be caused by a disruption of the processes involved in balancing the value of actions with their associated effort cost. © The Author (2016). Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Monte Carlo investigation of the increased radiation deposition due to gold nanoparticles using kilovoltage and megavoltage photons in a 3D randomized cell model.

PubMed

Douglass, Michael; Bezak, Eva; Penfold, Scott

2013-07-01

Investigation of increased radiation dose deposition due to gold nanoparticles (GNPs) using a 3D computational cell model during x-ray radiotherapy. Two GNP simulation scenarios were set up in Geant4; a single 400 nm diameter gold cluster randomly positioned in the cytoplasm and a 300 nm gold layer around the nucleus of the cell. Using an 80 kVp photon beam, the effect of GNP on the dose deposition in five modeled regions of the cell including cytoplasm, membrane, and nucleus was simulated. Two Geant4 physics lists were tested: the default Livermore and custom built Livermore/DNA hybrid physics list. 10(6) particles were simulated at 840 cells in the simulation. Each cell was randomly placed with random orientation and a diameter varying between 9 and 13 μm. A mathematical algorithm was used to ensure that none of the 840 cells overlapped. The energy dependence of the GNP physical dose enhancement effect was calculated by simulating the dose deposition in the cells with two energy spectra of 80 kVp and 6 MV. The contribution from Auger electrons was investigated by comparing the two GNP simulation scenarios while activating and deactivating atomic de-excitation processes in Geant4. The physical dose enhancement ratio (DER) of GNP was calculated using the Monte Carlo model. The model has demonstrated that the DER depends on the amount of gold and the position of the gold cluster within the cell. Individual cell regions experienced statistically significant (p < 0.05) change in absorbed dose (DER between 1 and 10) depending on the type of gold geometry used. The DER resulting from gold clusters attached to the cell nucleus had the more significant effect of the two cases (DER ≈ 55). The DER value calculated at 6 MV was shown to be at least an order of magnitude smaller than the DER values calculated for the 80 kVp spectrum. Based on simulations, when 80 kVp photons are used, Auger electrons have a statistically insignificant (p < 0.05) effect on the overall dose increase in the cell. The low energy of the Auger electrons produced prevents them from propagating more than 250-500 nm from the gold cluster and, therefore, has a negligible effect on the overall dose increase due to GNP. The results presented in the current work show that the primary dose enhancement is due to the production of additional photoelectrons.

New quasibound states of the compound nucleus in α -particle capture by the nucleus

NASA Astrophysics Data System (ADS)

Maydanyuk, Sergei P.; Zhang, Peng-Ming; Zou, Li-Ping

2017-07-01

We generalize the theory of nuclear decay and capture of Gamow that is based on tunneling through the barrier and internal oscillations inside the nucleus. In our formalism an additional factor is obtained, which describes distribution of the wave function of the the α particle inside the nuclear region. We discover new most stable states (called quasibound states) of the compound nucleus (CN) formed during the capture of α particle by the nucleus. With a simple example, we explain why these states cannot appear in traditional calculations of the α capture cross sections based on monotonic penetrabilities of a barrier, but they appear in a complete description of the evolution of the CN. Our result is obtained by a complete description of the CN evolution, which has the advantages of (1) a clear picture of the formation of the CN and its disintegration, (2) a detailed quantum description of the CN, (3) tests of the calculated amplitudes based on quantum mechanics (not realized in other approaches), and (4) high accuracy of calculations (not achieved in other approaches). These peculiarities are shown with the capture reaction of α +44Ca . We predict quasibound energy levels and determine fusion probabilities for this reaction. The difference between our approach and theory of quasistationary states with complex energies applied for the α capture is also discussed. We show (1) that theory does not provide calculations for the cross section of α capture (according to modern models of the α capture), in contrast with our formalism, and (2) these two approaches describe different states of the α capture (for the same α -nucleus potential).

Mass-loading of the solar wind at 67P/Churyumov-Gerasimenko. Observations and modelling

NASA Astrophysics Data System (ADS)

Behar, E.; Lindkvist, J.; Nilsson, H.; Holmström, M.; Stenberg-Wieser, G.; Ramstad, R.; Götz, C.

2016-11-01

Context. The first long-term in-situ observation of the plasma environment in the vicinity of a comet, as provided by the European Rosetta spacecraft. Aims: Here we offer characterisation of the solar wind flow near 67P/Churyumov-Gerasimenko (67P) and its long term evolution during low nucleus activity. We also aim to quantify and interpret the deflection and deceleration of the flow expected from ionization of neutral cometary particles within the undisturbed solar wind. Methods: We have analysed in situ ion and magnetic field data and combined this with hybrid modeling of the interaction between the solar wind and the comet atmosphere. Results: The solar wind deflection is increasing with decreasing heliocentric distances, and exhibits very little deceleration. This is seen both in observations and in modeled solar wind protons. According to our model, energy and momentum are transferred from the solar wind to the coma in a single region, centered on the nucleus, with a size in the order of 1000 km. This interaction affects, over larger scales, the downstream modeled solar wind flow. The energy gained by the cometary ions is a small fraction of the energy available in the solar wind. Conclusions: The deflection of the solar wind is the strongest and clearest signature of the mass-loading for a small, low-activity comet, whereas there is little deceleration of the solar wind.

Monte Carlo calculation of the maximum therapeutic gain of tumor antivascular alpha therapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huang, Chen-Yu; Oborn, Bradley M.; Guatelli, Susanna

Purpose: Metastatic melanoma lesions experienced marked regression after systemic targeted alpha therapy in a phase 1 clinical trial. This unexpected response was ascribed to tumor antivascular alpha therapy (TAVAT), in which effective tumor regression is achieved by killing endothelial cells (ECs) in tumor capillaries and, thus, depriving cancer cells of nutrition and oxygen. The purpose of this paper is to quantitatively analyze the therapeutic efficacy and safety of TAVAT by building up the testing Monte Carlo microdosimetric models. Methods: Geant4 was adapted to simulate the spatial nonuniform distribution of the alpha emitter {sup 213}Bi. The intraluminal model was designed tomore » simulate the background dose to normal tissue capillary ECs from the nontargeted activity in the blood. The perivascular model calculates the EC dose from the activity bound to the perivascular cancer cells. The key parameters are the probability of an alpha particle traversing an EC nucleus, the energy deposition, the lineal energy transfer, and the specific energy. These results were then applied to interpret the clinical trial. Cell survival rate and therapeutic gain were determined. Results: The specific energy for an alpha particle hitting an EC nucleus in the intraluminal and perivascular models is 0.35 and 0.37 Gy, respectively. As the average probability of traversal in these models is 2.7% and 1.1%, the mean specific energy per decay drops to 1.0 cGy and 0.4 cGy, which demonstrates that the source distribution has a significant impact on the dose. Using the melanoma clinical trial activity of 25 mCi, the dose to tumor EC nucleus is found to be 3.2 Gy and to a normal capillary EC nucleus to be 1.8 cGy. These data give a maximum therapeutic gain of about 180 and validate the TAVAT concept. Conclusions: TAVAT can deliver a cytotoxic dose to tumor capillaries without being toxic to normal tissue capillaries.« less

Heterogeneous nucleation from a supercooled ionic liquid on a carbon surface

NASA Astrophysics Data System (ADS)

He, Xiaoxia; Shen, Yan; Hung, Francisco R.; Santiso, Erik E.

2016-12-01

Classical molecular dynamics simulations were used to study the nucleation of the crystal phase of the ionic liquid [dmim+][Cl-] from its supercooled liquid phase, both in the bulk and in contact with a graphitic surface of D = 3 nm. By combining the string method in collective variables [Maragliano et al., J. Chem. Phys. 125, 024106 (2006)], with Markovian milestoning with Voronoi tessellations [Maragliano et al., J. Chem. Theory Comput. 5, 2589-2594 (2009)] and order parameters for molecular crystals [Santiso and Trout, J. Chem. Phys. 134, 064109 (2011)], we computed minimum free energy paths, the approximate size of the critical nucleus, the free energy barrier, and the rates involved in these nucleation processes. For homogeneous nucleation, the subcooled liquid phase has to overcome a free energy barrier of ˜85 kcal/mol to form a critical nucleus of size ˜3.6 nm, which then grows into the monoclinic crystal phase. This free energy barrier becomes about 42% smaller (˜49 kcal/mol) when the subcooled liquid phase is in contact with a graphitic disk, and the critical nucleus formed is about 17% smaller (˜3.0 nm) than the one observed for homogeneous nucleation. The crystal formed in the heterogeneous nucleation scenario has a structure that is similar to that of the bulk crystal, with the exception of the layers of ions next to the graphene surface, which have larger local density and the cations lie with their imidazolium rings parallel to the graphitic surface. The critical nucleus forms near the graphene surface separated only by these layers of ions. The heterogeneous nucleation rate (˜4.8 × 1011 cm-3 s-1) is about one order of magnitude faster than the homogeneous rate (˜6.6 × 1010 cm-3 s-1). The computed free energy barriers and nucleation rates are in reasonable agreement with experimental and simulation values obtained for the homogeneous and heterogeneous nucleation of other systems (ice, urea, Lennard-Jones spheres, and oxide glasses).

Heterogeneous nucleation from a supercooled ionic liquid on a carbon surface.

PubMed

He, Xiaoxia; Shen, Yan; Hung, Francisco R; Santiso, Erik E

2016-12-07

Classical molecular dynamics simulations were used to study the nucleation of the crystal phase of the ionic liquid [dmim + ][Cl - ] from its supercooled liquid phase, both in the bulk and in contact with a graphitic surface of D = 3 nm. By combining the string method in collective variables [Maragliano et al., J. Chem. Phys. 125, 024106 (2006)], with Markovian milestoning with Voronoi tessellations [Maragliano et al., J. Chem. Theory Comput. 5, 2589-2594 (2009)] and order parameters for molecular crystals [Santiso and Trout, J. Chem. Phys. 134, 064109 (2011)], we computed minimum free energy paths, the approximate size of the critical nucleus, the free energy barrier, and the rates involved in these nucleation processes. For homogeneous nucleation, the subcooled liquid phase has to overcome a free energy barrier of ∼85 kcal/mol to form a critical nucleus of size ∼3.6 nm, which then grows into the monoclinic crystal phase. This free energy barrier becomes about 42% smaller (∼49 kcal/mol) when the subcooled liquid phase is in contact with a graphitic disk, and the critical nucleus formed is about 17% smaller (∼3.0 nm) than the one observed for homogeneous nucleation. The crystal formed in the heterogeneous nucleation scenario has a structure that is similar to that of the bulk crystal, with the exception of the layers of ions next to the graphene surface, which have larger local density and the cations lie with their imidazolium rings parallel to the graphitic surface. The critical nucleus forms near the graphene surface separated only by these layers of ions. The heterogeneous nucleation rate (∼4.8 × 10 11 cm -3 s -1 ) is about one order of magnitude faster than the homogeneous rate (∼6.6 × 10 10 cm -3 s -1 ). The computed free energy barriers and nucleation rates are in reasonable agreement with experimental and simulation values obtained for the homogeneous and heterogeneous nucleation of other systems (ice, urea, Lennard-Jones spheres, and oxide glasses).

Neutrino-induced reactions on nuclei

NASA Astrophysics Data System (ADS)

Gallmeister, K.; Mosel, U.; Weil, J.

2016-09-01

Background: Long-baseline experiments such as the planned deep underground neutrino experiment (DUNE) require theoretical descriptions of the complete event in a neutrino-nucleus reaction. Since nuclear targets are used this requires a good understanding of neutrino-nucleus interactions. Purpose: Develop a consistent theory and code framework for the description of lepton-nucleus interactions that can be used to describe not only inclusive cross sections, but also the complete final state of the reaction. Methods: The Giessen-Boltzmann-Uehling-Uhlenbeck (GiBUU) implementation of quantum-kinetic transport theory is used, with improvements in its treatment of the nuclear ground state and of 2p2h interactions. For the latter an empirical structure function from electron scattering data is used as a basis. Results: Results for electron-induced inclusive cross sections are given as a necessary check for the overall quality of this approach. The calculated neutrino-induced inclusive double-differential cross sections show good agreement data from neutrino and antineutrino reactions for different neutrino flavors at MiniBooNE and T2K. Inclusive double-differential cross sections for MicroBooNE, NOvA, MINERvA, and LBNF/DUNE are given. Conclusions: Based on the GiBUU model of lepton-nucleus interactions a good theoretical description of inclusive electron-, neutrino-, and antineutrino-nucleus data over a wide range of energies, different neutrino flavors, and different experiments is now possible. Since no tuning is involved this theory and code should be reliable also for new energy regimes and target masses.

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

NASA Astrophysics Data System (ADS)

Hrtánková, Jaroslava; Mareš, Jiří

2018-01-01

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

Axial deformed solution of the Skyrme-Hartree-Fock-Bogolyubov equations using the transformed harmonic oscillator Basis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Perez, R. Navarro; Schunck, N.; Lasseri, R.

2017-03-09

HFBTHO is a physics computer code that is used to model the structure of the nucleus. It is an implementation of the nuclear energy Density Functional Theory (DFT), where the energy of the nucleus is obtained by integration over space of some phenomenological energy density, which is itself a functional of the neutron and proton densities. In HFBTHO, the energy density derives either from the zero-range Dkyrme or the finite-range Gogny effective two-body interaction between nucleons. Nuclear superfluidity is treated at the Hartree-Fock-Bogoliubov (HFB) approximation, and axial-symmetry of the nuclear shape is assumed. This version is the 3rd release ofmore » the program; the two previous versions were published in Computer Physics Communications [1,2]. The previous version was released at LLNL under GPL 3 Open Source License and was given release code LLNL-CODE-573953.« less

Statistical γ -decay properties of 64Ni and deduced (n ,γ ) cross section of the s -process branch-point nucleus 63Ni

NASA Astrophysics Data System (ADS)

Crespo Campo, L.; Bello Garrote, F. L.; Eriksen, T. K.; Görgen, A.; Guttormsen, M.; Hadynska-Klek, K.; Klintefjord, M.; Larsen, A. C.; Renstrøm, T.; Sahin, E.; Siem, S.; Springer, A.; Tornyi, T. G.; Tveten, G. M.

2016-10-01

Particle-γ coincidence data have been analyzed to obtain the nuclear level density and the γ -strength function of 64Ni by means of the Oslo method. The level density found in this work is in very good agreement with known energy levels at low excitation energies as well as with data deduced from particle-evaporation measurements at excitation energies above Ex≈5.5 MeV. The experimental γ -strength function presents an enhancement at γ energies below Eγ≈3 MeV and possibly a resonancelike structure centered at Eγ≈9.2 MeV. The obtained nuclear level density and γ -strength function have been used to estimate the (n ,γ ) cross section for the s -process branch-point nucleus 63Ni, of particular interest for astrophysical calculations of elemental abundances.

A deep NuSTAR observation of M51: Investigating its Compton-thick nucleus, LINER companion and ULXs above 10 keV

NASA Astrophysics Data System (ADS)

Brightman, Murray; Annuar, Ady; Alexander, David M.; Earnshaw, Hannah; Gandhi, Poshak; Hornschemeier, Ann E.; Lehmer, Bret; Ptak, Andrew; Rangelov, Blagoy; Roberts, Tim P.; Stern, Daniel; Zezas, Andreas

2017-08-01

We present the results from a deep 200ks observation of M51 with NuSTAR. This observation was taken simultaneously with Chandra to provide soft-X-ray-coverage as well as to resolve the different point sources. We detect the Compton-thick nucleus of M51a, the LINER nucleus of M51b and several ultraluminous X-ray sources located in the galaxies above 10 keV. From X-ray torus modeling, we find that the covering factor of the torus in the nucleus of M51a is ~40% and supports a decline in the obscured fration at low X-ray luminosities. We find that the X-ray spectrum of the intermediate mass black hole candidate, ULX-7, is consistent with a power-law up to high energies, supporting its IMBH status. We further resolve the nucleus of M51b into two X-ray sources with Chandra, and measure its X-ray luminosity.

The Pt site reactivity of the molecular graphs of Au6Pt isomers

NASA Astrophysics Data System (ADS)

Xu, Tianlv; Jenkins, Samantha; Xiao, Chen-Xia; Maza, Julio R.; Kirk, Steven R.

2013-12-01

Within the framework of the theory of atoms in molecules (QTAIM), in an exploratory study we propose a new measure of site reactivity equivalent to the atomic coordination number based purely on the electronic structure. It was found that the number of ring critical points (NNRCPs) positioned on the boundary of the atomic basin of the dopant (Pt) nucleus correlated very well with the relative zero point energy (ZPE) corrected energies. A weaker condition (i.e. than the number of associated bond paths) for the association of the dopant Pt nucleus with the Au6Pt molecular graph is found for NNRCP = 0.

In-Beam Gamma-ray Spectroscopy in the sdpf 37Ar Nucleus

NASA Astrophysics Data System (ADS)

Silveira, M. A. G.; Medina, N. H.; Seale, W. A.; Ribas, R. V.; de Oliveira, J. R. B.; Zilio, S.; Lenzi, S. M.; Napoli, D. R.; Marginean, N.; Vedova, F. Della; Farnea, E.; Ionescu-Bujor, M.; Iordachescu, A.

2007-10-01

The nucleus 37Ar has been studied with γ-ray spectroscopy in the 24Mg(16O,2pn) reaction at a beam energy of 70 MeV. Twenty two new excited states up to an excitation energy of 13 MeV have been observed. We compare the first negative and positive parity yrast states with large-scale-shell-model calculations using the Antoine code and the SDPF interaction, considering the excitation of the 1d5/2,2s1/2 and 1d3/2 nucleons to 1f7/2 and 2p3/2 in the sdpf valence space.

Radio and X-ray variability of the nucleus of Centaurus A /NGC 5128/

NASA Technical Reports Server (NTRS)

Beall, J. H.; Rose, W. K.; Graf, W.; Price, K. M.; Dent, W. A.; Hobbs, R. W.; Dennis, B. R.; Crannell, C. J.; Conklin, E. K.; Ulich, B. L.

1978-01-01

Centaurus A (NGC 5128) has been observed at radio frequencies of 10.7, 31.4, 85.2, and 89 GHz and at X-ray energies greater than 20 keV. These observations, together with results reported by other workers, are interpreted in terms of models of the nucleus of this radio galaxy. The radio observations cover the period from 1973 through early 1977. The X-ray observations cover two 10-day intervals, one in July and August (1975) and the other in July and August 1976. The source exhibits significant variability in all the observed radio frequencies. The observed radio and X-ray intensities show some concurrent variations but do not track one another throughout the observations. A model of the source in which X-rays are produced by inverse Compton scattering of blackbody photons by relativistic electrons is proposed to explain these observations. The observed variations in the electromagnetic spectrum are shown to be consistent with adiabatic expansion of a trapped plasma in conjunction with turbulent accelerations of the relativistic electrons. Upper limits obtained with the model indicate that there may be sufficient energy available in the nucleus to form radio lobes with the same total energy as those already present.

Energy dependence of strangeness production and event-byevent fluctuations

NASA Astrophysics Data System (ADS)

Rustamov, Anar

2018-02-01

We review the energy dependence of strangeness production in nucleus-nucleus collisions and contrast it with the experimental observations in pp and p-A collisions at LHC energies as a function of the charged particle multiplicities. For the high multiplicity final states the results from pp and p-Pb reactions systematically approach the values obtained from Pb-Pb collisions. In statistical models this implies an approach to the thermodynamic limit, where differences of mean multiplicities between various formalisms, such as Canonical and Grand Canonical Ensembles, vanish. Furthermore, we report on event-by-event net-proton fluctuations as measured by STAR at RHIC/BNL and by ALICE at LHC/CERN and discuss various non-dynamical contributions to these measurements, which should be properly subtracted before comparison to theoretical calculations on dynamical net-baryon fluctuations.

Regional Differential Effects of the Novel Histamine H3 Receptor Antagonist 6-[(3-Cyclobutyl-2,3,4,5-tetrahydro-1H-3-benzazepin-7-yl)oxy]-N-methyl-3-pyridinecarboxamide hydrochloride (GSK189254) on Histamine Release in the Central Nervous System of Freely Moving Rats

PubMed Central

Giannoni, Patrizia; Medhurst, Andrew D.; Passani, Maria Beatrice; Giovannini, Maria Grazia; Ballini, Chiara; Corte, Laura Della

2010-01-01

After oral administration, the nonimidazole histamine H3 receptor antagonist, 6-[(3-cyclobutyl-2,3,4,5-tetrahydro-1H-3-benzazepin-7-yl)oxy]-N-methyl-3-pyridinecarboxamide hydrochloride (GSK189254), increased histamine release from the tuberomammillary nucleus, where all histaminergic somata are localized, and from where their axons project to the entire brain. To further understand functional histaminergic circuitry in the brain, dual-probe microdialysis was used to pharmacologically block H3 receptors in the tuberomammillary nucleus, and monitor histamine release in projection areas. Perfusion of the tuberomammillary nucleus with GSK189254 increased histamine release from the tuberomammillary nucleus, nucleus basalis magnocellularis, and cortex, but not from the striatum or nucleus accumbens. Cortical acetylcholine (ACh) release was also increased, but striatal dopamine release was not affected. When administered locally, GSK189254 increased histamine release from the nucleus basalis magnocellularis, but not from the striatum. Thus, defined by their sensitivity to GSK189254, histaminergic neurons establish distinct pathways according to their terminal projections, and can differentially modulate neurotransmitter release in a brain region-specific manner. Consistent with its effects on cortical ACh release, systemic administration of GSK189254 antagonized the amnesic effects of scopolamine in the rat object recognition test, a cognition paradigm with important cortical components. PMID:19815811

Bidirectional modulation of fear extinction by mediodorsal thalamic firing in mice.

PubMed

Lee, Sukchan; Ahmed, Touqeer; Lee, Soojung; Kim, Huisu; Choi, Sukwoo; Kim, Duk-Soo; Kim, Sang Jeong; Cho, Jeiwon; Shin, Hee-Sup

2011-12-25

The mediodorsal thalamic nucleus has been implicated in the control of memory processes. However, the underlying neural mechanism remains unclear. Here we provide evidence for bidirectional modulation of fear extinction by the mediodorsal thalamic nucleus. Mice with a knockout or mediodorsal thalamic nucleus-specific knockdown of phospholipase C β4 exhibited impaired fear extinction. Mutant mediodorsal thalamic nucleus neurons in slices showed enhanced burst firing accompanied by increased T-type Ca(2+) currents; blocking of T channels in vivo rescued the fear extinction. Tetrode recordings in freely moving mice revealed that, during extinction, the single-spike (tonic) frequency of mediodorsal thalamic nucleus neurons increased in wild-type mice, but was static in mutant mice. Furthermore, tonic-evoking microstimulations of the mediodorsal thalamic nucleus, contemporaneous with the extinction tones, rescued fear extinction in mutant mice and facilitated it in wild-type mice. In contrast, burst-evoking microstimulation suppressed extinction in wild-type mice, mimicking the mutation. These results suggest that the firing mode of the mediodorsal thalamic nucleus is critical for the modulation of fear extinction.

Cross section calculations for subthreshold pion production in peripheral heavy-ion collisions

NASA Technical Reports Server (NTRS)

Norbury, J. W.; Cucinotta, F. A.; Deutchman, P. A.; Townsend, L. W.

1986-01-01

Total cross sections angular distributions, and spectral distributions for the exclusive production of charged and neutral subthreshold pions produced in peripheral nucleus-nucleus collisions are calculated by using a particle-hole formalism. The pions result from the formation and decay of an isobar giant resonance state formed in a C-12 nucleus. From considerations of angular momentum conservation and for the sake of providing a unique experimental signature, the other nucleus, chosen for this work to be C-12 also, is assumed to be excited to one of its isovector (1+) giant resonance states. The effects of nucleon recoil by the pion emission are included, and Pauli blocking and pion absorption effects are studied by varying the isobar width. Detailed comparisons with experimental subthreshold pion data for incident energies between 35 and 86 MeV/nucleon are made.

Long-lived K isomer and enhanced γ vibration in the neutron-rich nucleus 172Dy: Collectivity beyond double midshell

NASA Astrophysics Data System (ADS)

Watanabe, H.; Zhang, G. X.; Yoshida, K.; Walker, P. M.; Liu, J. J.; Wu, J.; Regan, P. H.; Söderström, P.-A.; Kanaoka, H.; Korkulu, Z.; Lee, P. S.; Nishimura, S.; Yagi, A.; Ahn, D. S.; Alharbi, T.; Baba, H.; Browne, F.; Bruce, A. M.; Carroll, R. J.; Chae, K. Y.; Dombradi, Zs.; Doornenbal, P.; Estrade, A.; Fukuda, N.; Griffin, C.; Ideguchi, E.; Inabe, N.; Isobe, T.; Kanaya, S.; Kojouharov, I.; Kondev, F. G.; Kubo, T.; Kubono, S.; Kurz, N.; Kuti, I.; Lalkovski, S.; Lane, G. J.; Lee, C. S.; Lee, E. J.; Lorusso, G.; Lotay, G.; Moon, C.-B.; Nishizuka, I.; Nita, C. R.; Odahara, A.; Patel, Z.; Phong, V. H.; Podolyák, Zs.; Roberts, O. J.; Sakurai, H.; Schaffner, H.; Shand, C. M.; Shimizu, Y.; Sumikama, T.; Suzuki, H.; Takeda, H.; Terashima, S.; Vajta, Zs.; Valiente-Dóbon, J. J.; Xu, Z. Y.

2016-09-01

The level structure of 172Dy has been investigated for the first time by means of decay spectroscopy following in-flight fission of a 238U beam. A long-lived isomeric state with T1/2 = 0.71 (5) s and Kπ =8- has been identified at 1278 keV, which decays to the ground-state and γ-vibrational bands through hindered electromagnetic transitions, as well as to the daughter nucleus 172Ho via allowed β decays. The robust nature of the Kπ =8- isomer and the ground-state rotational band reveals an axially-symmetric structure for this nucleus. Meanwhile, the γ-vibrational levels have been identified at unusually low excitation energy compared to the neighboring well-deformed nuclei, indicating the significance of the microscopic effect on the non-axial collectivity in this doubly mid-shell region. The underlying mechanism of enhanced γ vibration is discussed in comparison with the deformed Quasiparticle Random-Phase Approximation based on a Skyrme energy-density functional.

\\psi (2S) enhancement in p-Pb collision as an indication of quark-gluon plasma formation at the Large Hadron Collider

NASA Astrophysics Data System (ADS)

Ganesh, S.; Singh, R., Captain; Mishra, M.

2018-03-01

Proton-nucleus collisions serve as an important baseline for the understanding and interpretation of the nucleus-nucleus collisions. These collisions have been employed to characterize the cold nuclear matter effects at SPS and Relativistic Heavy-Ion Collider energies for the past several years, as it was thought that quark-gluon plasma (QGP) is not formed in such collisions. However, at the Large Hadron Collider (LHC), there seems a possibility that QGP is formed during proton-lead (p-Pb) collisions. In this work, we have derived an expression for gluon induced excitation of J/\\psi to \\psi (2S), using pNRQCD, and show that the relative enhancement of \\psi (2S) vis-à-vis J/\\psi , especially at high p T , gives further indication that the QGP is indeed formed in p-Pb collisions at the most central collisions at LHC energy. J/\\psi and \\psi (2S) suppression effects seen at ALICE are also qualitatively explained.

Electrical coupling: novel mechanism for sleep-wake control.

PubMed

Garcia-Rill, Edgar; Heister, David S; Ye, Meijun; Charlesworth, Amanda; Hayar, Abdallah

2007-11-01

Recent evidence suggests that certain anesthetic agents decrease electrical coupling, whereas the stimulant modafinil appears to increase electrical coupling. We investigated the potential role of electrical coupling in 2 reticular activating system sites, the subcoeruleus nucleus and in the pedunculopontine nucleus, which has been implicated in the modulation of arousal via ascending cholinergic activation of intralaminar thalamus and descending activation of the subcoeruleus nucleus to generate some of the signs of rapid eye movement sleep. We used 6- to 30-day-old rat pups to obtain brainstem slices to perform whole-cell patch-clamp recordings. Recordings from single cells revealed the presence of spikelets, manifestations of action potentials in coupled cells, and of dye coupling of neurons in the pedunculopontine nucleus. Recordings in pairs of pedunculopontine nucleus and subcoeruleus nucleus neurons revealed that some of these were electrically coupled with coupling coefficients of approximately 2%. After blockade of fast synaptic transmission, the cholinergic agonist carbachol was found to induce rhythmic activity in pedunculopontine nucleus and subcoeruleus nucleus neurons, an effect eliminated by the gap junction blockers carbenoxolone or mefloquine. The stimulant modafinil was found to decrease resistance in neurons in the pedunculopontine nucleus and subcoeruleus nucleus after fast synaptic blockade, indicating that the effect may be due to increased coupling. The finding of electrical coupling in specific reticular activating system cell groups supports the concept that this underlying process behind specific neurotransmitter interactions modulates ensemble activity across cell populations to promote changes in sleep-wake state.

Intracerebroventricular Catalase Reduces Hepatic Insulin Sensitivity and Increases Responses to Hypoglycemia in Rats.

PubMed

Pauliina Markkula, S; Lyons, David; Yueh, Chen-Yu; Riches, Christine; Hurst, Paul; Fielding, Barbara; Heisler, Lora K; Evans, Mark L

2016-12-01

Specialized metabolic sensors in the hypothalamus regulate blood glucose levels by influencing hepatic glucose output and hypoglycemic counterregulatory responses. Hypothalamic reactive oxygen species (ROS) may act as a metabolic signal-mediating responses to changes in glucose, other substrates and hormones. The role of ROS in the brain's control of glucose homeostasis remains unclear. We hypothesized that hydrogen peroxide (H 2 O 2 ), a relatively stable form of ROS, acts as a sensor of neuronal glucose consumption and availability and that lowering brain H 2 O 2 with the enzyme catalase would lead to systemic responses increasing blood glucose. During hyperinsulinemic euglycemic clamps in rats, intracerebroventricular catalase infusion resulted in increased hepatic glucose output, which was associated with reduced neuronal activity in the arcuate nucleus of the hypothalamus. Electrophysiological recordings revealed a subset of arcuate nucleus neurons expressing proopiomelanocortin that were inhibited by catalase and excited by H 2 O 2 . During hypoglycemic clamps, intracerebroventricular catalase increased glucagon and epinephrine responses to hypoglycemia, consistent with perceived lower glucose levels. Our data suggest that H 2 O 2 represents an important metabolic cue, which, through tuning the electrical activity of key neuronal populations such as proopiomelanocortin neurons, may have a role in the brain's influence of glucose homeostasis and energy balance.

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

NASA Astrophysics Data System (ADS)

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

2016-05-01

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

Role of nesprin-1 in nuclear deformation in endothelial cells under static and uniaxial stretching conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anno, Toshiro; Sakamoto, Naoya, E-mail: sakan@me.kawasaki-m.ac.jp; Sato, Masaaki

Highlights: Black-Right-Pointing-Pointer Nesprin-1 knockdown decreases widths of nuclei in ECs under static condition. Black-Right-Pointing-Pointer Nuclear strain caused by stretching is increased by nesprin-1 knockdown in ECs. Black-Right-Pointing-Pointer We model mechanical interactions of F-actin with the nucleus in stretched cells. Black-Right-Pointing-Pointer F-actin bound to nesprin-1 may cause sustainable force transmission to the nucleus. -- Abstract: The linker of nucleus and cytoskeleton (LINC) complex, including nesprin-1, has been suggested to be crucial for many biological processes. Previous studies have shown that mutations in nesprin-1 cause abnormal cellular functions and diseases, possibly because of insufficient force transmission to the nucleus through actin filamentsmore » (F-actin) bound to nesprin-1. However, little is known regarding the mechanical interaction between the nucleus and F-actin through nesprin-1. In this study, we examined nuclear deformation behavior in nesprin-1 knocked-down endothelial cells (ECs) subjected to uniaxial stretching by evaluating nuclear strain from lateral cross-sectional images. The widths of nuclei in nesprin-1 knocked-down ECs were smaller than those in wild-type cells. In addition, nuclear strain in nesprin-1 knocked-down cells, which is considered to be compressed by the actin cortical layer, increased compared with that in wild-type cells under stretching condition. These results indicate that nesprin-1 knockdown releases the nucleus from the tension of F-actin bound to the nucleus, thereby increasing allowance for deformation before stretching, and that F-actin bound to the nucleus through nesprin-1 causes sustainable force transmission to the nucleus.« less

Sexual behavior induction of c-Fos in the nucleus accumbens and amphetamine-stimulated locomotor activity are sensitized by previous sexual experience in female Syrian hamsters.

PubMed

Bradley, K C; Meisel, R L

2001-03-15

Dopamine transmission in the nucleus accumbens can be activated by drugs, stress, or motivated behaviors, and repeated exposure to these stimuli can sensitize this dopamine response. The objectives of this study were to determine whether female sexual behavior activates nucleus accumbens neurons and whether past sexual experience cross-sensitizes neuronal responses in the nucleus accumbens to amphetamine. Using immunocytochemical labeling, c-Fos expression in different subregions (shell vs core at the rostral, middle, and caudal levels) of the nucleus accumbens was examined in female hamsters that had varying amounts of sexual experience. Female hamsters, given either 6 weeks of sexual experience or remaining sexually naive, were tested for sexual behavior by exposure to adult male hamsters. Previous sexual experience increased c-Fos labeling in the rostral and caudal levels but not in the middle levels of the nucleus accumbens. Testing for sexual behavior increased labeling in the core, but not the shell, of the nucleus accumbens. To validate that female sexual behavior can sensitize neurons in the mesolimbic dopamine pathway, the locomotor responses of sexually experienced and sexually naive females to an amphetamine injection were then compared. Amphetamine increased general locomotor activity in all females. However, sexually experienced animals responded sooner to amphetamine than did sexually naive animals. These data indicate that female sexual behavior can activate neurons in the nucleus accumbens and that sexual experience can cross-sensitize neuronal responses to amphetamine. In addition, these results provide additional evidence for functional differences between the shell and core of the nucleus accumbens and across its anteroposterior axis.

Total absorption γ -ray spectroscopy of the β -delayed neutron emitters Br 87 , Br 88 , and Rb 94

DOE Office of Scientific and Technical Information (OSTI.GOV)

Valencia, E.; Tain, J. L.; Algora, A.

2017-02-01

We investigate the decay of Br-87,Br-88 and Rb-94 using total absorption gamma-ray spectroscopy. These important fission products are beta-delayed neutron emitters. Our data show considerable beta gamma intensity, so far unobserved in high-resolution gamma-ray spectroscopy, from states at high excitation energy. We also find significant differences with the beta intensity that can be deduced from existing measurements of the beta spectrum. We evaluate the impact of the present data on reactor decay heat using summation calculations. Although the effect is relatively small it helps to reduce the discrepancy between calculations and integral measurements of the photon component for U-235 fissionmore » at cooling times in the range 1-100 s. We also use summation calculations to evaluate the impact of present data on reactor antineutrino spectra. We find a significant effect at antineutrino energies in the range of 5 to 9 MeV. In addition, we observe an unexpected strong probability for. emission from neutron unbound states populated in the daughter nucleus. The. branching is compared to Hauser-Feshbach calculations, which allow one to explain the large value for bromine isotopes as due to nuclear structure. However the branching for Rb-94, although much smaller, hints of the need to increase the radiative width gamma by one order of magnitude. This increase in gamma would lead to a similar increase in the calculated (n, gamma) cross section for this very neutron-rich nucleus with a potential impact on r process abundance calculations.« less

Single-prolonged stress induces apoptosis in dorsal raphe nucleus in the rat model of posttraumatic stress disorder

PubMed Central

2012-01-01

Introduction Post-traumatic stress disorder (PTSD) is an anxiety disorder that develops after exposure to a life-threatening traumatic experience. Meta-analyses of the brainstem showed that midsagittal area of the pons was significantly reduced in patients with PTSD, suggesting a potential apoptosis in dorsal raphe nucleus after single-prolonged stress (SPS). The aim of this study is to investigate whether SPS induces apoptosis in dorsal raphe nucleus in PTSD rats, which may be a possible mechanism of reduced volume of pons and density of gray matter. Methods In this study, rats were randomly divided into 1d, 7d and 14d groups after SPS along with the control group. The apoptosis rate was determined using annexin V-FITC/PI double-labeled flow cytometry (FCM). Levels of Cytochrome c (Cyt-C) was examined by Western blotting. Expression of Cyt-C on mitochondria in the dorsal raphe nucleus neuron was determined by enzymohistochemistry under transmission electron microscopy (TEM). The change of thiamine monophosphatase (TMP) levels was assessed by enzymohistochemistry under light microscope and TEM. Morphological changes of the ultrastructure of the dorsal raphe nucleus neuron were determined by TEM. Results Apoptotic morphological alterations were observed in dorsal raphe nucleus neuron for all SPS-stimulate groups of rats. The apoptosis rates were significantly increased in dorsal raphe nucleus neuron of SPS rats, along with increased release of cytochrome c from the mitochondria into the cytoplasm, increased expression of Cyt-C and TMP levels in the cytoplasm, which reached to the peak of increase 7 days of SPS. Conclusions The results indicate that SPS induced Cyt-C released from mitochondria into cytosol and apoptosis in dorsal raphe nucleus neuron of rats. Increased TMP in cytoplasm facilitated the clearance of apoptotic cells. We propose that this presents one of the mechanisms that lead to reduced volume of pons and gray matter associated with PTSD. PMID:23181934

Extraction of In-Medium Nucleon-Nucleon Amplitude From Experiment

NASA Technical Reports Server (NTRS)

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

1998-01-01

The in-medium nucleon-nucleon amplitudes are extracted from the available proton-nucleus total reaction cross sections data. The retrieval of the information from the experiment makes the estimate of reaction cross sections very reliable. Simple expressions are given for the in-medium nucleon-nucleon amplitudes for any system of colliding nuclei as a function of energy. Excellent agreement with experimental observations is demonstrated in the ion-nucleus interactions.

Temperature dependence of stacking faults in catalyst-free GaAs nanopillars.

PubMed

Shapiro, Joshua N; Lin, Andrew; Ratsch, Christian; Huffaker, D L

2013-11-29

Impressive opto-electronic devices and transistors have recently been fabricated from GaAs nanopillars grown by catalyst-free selective-area epitaxy, but this growth technique has always resulted in high densities of stacking faults. A stacking fault occurs when atoms on the growing (111) surface occupy the sites of a hexagonal-close-pack (hcp) lattice instead of the normal face-centered-cubic (fcc) lattice sites. When stacking faults occur consecutively, the crystal structure is locally wurtzite instead of zinc-blende, and the resulting band offsets are known to negatively impact device performance. Here we present experimental and theoretical evidence that indicate stacking fault formation is related to the size of the critical nucleus, which is temperature dependent. The difference in energy between the hcp and fcc orientation of small nuclei is computed using density-function theory. The minimum energy difference of 0.22 eV is calculated for a nucleus with 21 atoms, so the population of nuclei in the hcp orientation is expected to decrease as the nucleus grows larger. The experiment shows that stacking fault occurrence is dramatically reduced from 22% to 3% by raising the growth temperature from 730 to 790 ° C. These data are interpreted using classical nucleation theory which dictates a larger critical nucleus at higher growth temperature.

Semiclassical approach to atomic decoherence by gravitational waves

NASA Astrophysics Data System (ADS)

Quiñones, D. A.; Varcoe, B. T. H.

2018-01-01

A new heuristic model of interaction of an atomic system with a gravitational wave (GW) is proposed. In it, the GW alters the local electromagnetic field of the atomic nucleus, as perceived by the electron, changing the state of the system. The spectral decomposition of the wave function is calculated, from which the energy is obtained. The results suggest a shift in the difference of the atomic energy levels, which will induce a small detuning to a resonant transition. The detuning increases with the quantum numbers of the levels, making the effect more prominent for Rydberg states. We performed calculations on the Rabi oscillations of atomic transitions, estimating how they would vary as a result of the proposed effect.

Mutation induction in yeast by very heavy ions

NASA Astrophysics Data System (ADS)

Kiefer, J.

1994-10-01

Resistance to canavanine was studied in haploid yeast after exposure to heavy ions (argon to uranium) of energies between 1 and 10 MeV/u covering a LET-range up to about 10000 keV/μm. Mutations were found in all instances but the induction cross sections increased with ion energy. This is taken to mean that the contribution of penumbra electrons plays an important role. The probability to recover surviving mutants is highest if the cell is not directly hit by the particle. The experiments demonstrate that the geometrical dimensions of the target cell nucleus as well as its sensitivity in terms of survival have a critical influence on mutation induction with very heavy ions.

Determination of Fusion Barrier Distributions from Quasielastic Scattering Cross Sections towards Superheavy Nuclei Synthesis

NASA Astrophysics Data System (ADS)

Tanaka, Taiki; Narikiyo, Yoshihiro; Morita, Kosuke; Fujita, Kunihiro; Kaji, Daiya; Morimoto, Kouji; Yamaki, Sayaka; Wakabayashi, Yasuo; Tanaka, Kengo; Takeyama, Mirei; Yoneda, Akira; Haba, Hiromitsu; Komori, Yukiko; Yanou, Shinya; Jean-Paul Gall, Benoît; Asfari, Zouhair; Faure, Hugo; Hasebe, Hiroo; Huang, Minghui; Kanaya, Jumpei; Murakami, Masashi; Yoshida, Atsushi; Yamaguchi, Takayuki; Tokanai, Fuyuki; Yoshida, Tomomi; Yamamoto, Shoya; Yamano, Yuki; Watanabe, Kenyu; Ishizawa, Satoshi; Asai, Masato; Aono, Ryuji; Goto, Shin-ichi; Katori, Kenji; Hagino, Kouichi

2018-01-01

In order to study the nucleus-nucleus interactions for syntheses of superheavy nuclei, we measured excitation functions for the quasielastic scattering of 48Ca+208Pb, 50Ti+208Pb, and 48Ca+248Cm using the gas-filled-type recoil ion separator GARIS. The quasielastic scattering events were clearly separated from deep-inelastic events by using GARIS and its focal plan detectors, except for high-incident-energy points. The quasielastic barrier distributions were successfully extracted for these systems, and compared with coupled-channels calculations. The results of the calculations indicate that vibrational and rotational excitations of the colliding nuclei, as well as neutron transfers before contact, strongly affect the structure of the barrier distribution. For the reactions of 48Ca+208Pb and 50Ti+208Pb, a local maximum of the barrier distribution occurred at the same energy as the peak of the 2n evaporation cross section of the system. On the other hand, for the hot fusion reaction of 48Ca+248Cm, the 4n evaporation cross section of the system peaks at energies well above the maximum of the barrier distribution. This may be attributed to the deformation of the target nucleus. We argue that these findings can be utilized to locate the optimal energy for future searches for undiscovered superheavy nuclei.

MUPUS --- a Suite of Small Instruments for the ROSETTA Surface Science Package to Measure the Thermal and Mechanical Properties of a Comet Nucleus

NASA Astrophysics Data System (ADS)

Spohn, T.; MUPUS Team

1996-09-01

The Surface Science Package, which will be deployed in course of the ROSETTA mission on the surface of the target comet, offers the unprecedented opportunity to study the physical properties and dominating processes of a comet nucleus in situ. While most SSP experiments focuse on composition and chemistry, the MUPUS instrument package is aimed to study the energy balance of the nucleus/coma interface and the evolution of key thermal and mechanical parameters. Unlike planetary evolution, cometary evolution is influenced by the energy input at the surface. The near surface layers are accessible with some effort and may thus be directly studied. A penetrator equipped with temperature sensors and heaters (MUPUS--PEN) aims to measure the vertical temperature distribution (PEN--TP) and the thermal conductivity (PEN--THC) in the first tens of centimeters of the nucleus as they evolve with time. A combined evaluation of the PEN--TP and PEN--THC data will allow to understand vertical surface heat flow into or from the comet nucleus and the energy balance of the comet. The surface temperature will be measured with an infrared thermal mapper (MUPUS TM). Both thermal sensors will provide a ground truth for IR data from the orbiter. The PEN--M sensor will measure mechanical properties like hardness and grain size during penetration. A compton backscatter densitometer (CBD) will be used to measure the density. Additional temperature sensors and penetrometers in the SSP's anchor(s) will supplement the data and expand the volume probed. The results will help to understand the onset of activity, gas and dust emission, which will be measured by the orbiter. Understanding the dominating processes and their time scales allows to determine the present state of the surface material ("Is the matter found close to the surface pristine?") as well as extrapolation both into the past and the future.

Cosmic mass spectrometer

NASA Astrophysics Data System (ADS)

Anchordoqui, Luis A.; Barger, Vernon; Weiler, Thomas J.

2018-03-01

We argue that if ultrahigh-energy (E ≳1010GeV) cosmic rays are heavy nuclei (as indicated by existing data), then the pointing of cosmic rays to their nearest extragalactic sources is expected for 1010.6 ≲ E /GeV ≲1011. This is because for a nucleus of charge Ze and baryon number A, the bending of the cosmic ray decreases as Z / E with rising energy, so that pointing to nearby sources becomes possible in this particular energy range. In addition, the maximum energy of acceleration capability of the sources grows linearly in Z, while the energy loss per distance traveled decreases with increasing A. Each of these two points tend to favor heavy nuclei at the highest energies. The traditional bi-dimensional analyses, which simultaneously reproduce Auger data on the spectrum and nuclear composition, may not be capable of incorporating the relative importance of all these phenomena. In this paper we propose a multi-dimensional reconstruction of the individual emission spectra (in E, direction, and cross-correlation with nearby putative sources) to study the hypothesis that primaries are heavy nuclei subject to GZK photo-disintegration, and to determine the nature of the extragalactic sources. More specifically, we propose to combine information on nuclear composition and arrival direction to associate a potential clustering of events with a 3-dimensional position in the sky. Actually, both the source distance and maximum emission energy can be obtained through a multi-parameter likelihood analysis to accommodate the observed nuclear composition of each individual event in the cluster. We show that one can track the level of GZK interactions on an statistical basis by comparing the maximum energy at the source of each cluster. We also show that nucleus-emitting-sources exhibit a cepa stratis structure on Earth which could be pealed off by future space-missions, such as POEMMA. Finally, we demonstrate that metal-rich starburst galaxies are highly-plausible candidate sources, and we use them as an explicit example of our proposed multi-dimensional analysis.

Forward-backward multiplicity correlations of target fragments in nucleus-emulsion collisions at a few hundred MeV/u

NASA Astrophysics Data System (ADS)

Zhang, Dong-Hai; Chen, Yan-Ling; Wang, Guo-Rong; Li, Wang-Dong; Wang, Qing; Yao, Ji-Jie; Zhou, Jian-Guo; Li, Rong; Li, Jun-Sheng; Li, Hui-Ling

2015-01-01

The forward-backward multiplicity and correlations of a target evaporated fragment (black track particle) and target recoiled proton (grey track particle) emitted from 150 A MeV 4He, 290 A MeV 12C, 400 A MeV 12C, 400 A MeV 20Ne and 500 A MeV 56Fe induced different types of nuclear emulsion target interactions are investigated. It is found that the forward and backward averaged multiplicity of a grey, black and heavily ionized track particle increases with the increase of the target size. The averaged multiplicity of a forward black track particle, backward black track particle, and backward grey track particle do not depend on the projectile size and energy, but the averaged multiplicity of a forward grey track particle increases with an increase of projectile size and energy. The backward grey track particle multiplicity distribution follows an exponential decay law and the decay constant decreases with an increase of target size. The backward-forward multiplicity correlations follow linear law which is independent of the projectile size and energy, and the saturation effect is observed in some heavy target data sets.

Near-barrier Fusion Evaporation and Fission of 28Si+174Yb and 32S+170Er

NASA Astrophysics Data System (ADS)

Wang, Dongxi; Lin, Chengjian; Jia, Huiming; Ma, Nanru; Sun, Lijie; Xu, Xinxing; Yang, Lei; Yang, Feng; Zhang, Huanqiao; Bao, Pengfei

2017-11-01

Fusion evaporation residues and fission fragments have been measured, respectively, at energies around the Coulomb barrier for the 28Si+174Yb and 32S+170Er systems forming the same compound nucleus 202Po. The excitation function of fusion evaporation, fission as well as capture reactions were deduced. Coupled-channels analyses reveal that couplings to the deformations of targets and the two-phonon states of projectiles contribute much to the enhancement of capture cross sections at sub-barrier energies. The mass and total kinetic energy of fission fragments were deduced by the time-difference method assuming full momentum transfer in a two-body kinematics. The mass-energy and mass-angle distributions were obtained and no obvious quasi-fission components were observed in this bombarding energy range. Further, mass distributions of fission fragments were fitted to extract their widths. Results show that the mass widths decrease monotonically with decreasing energy, but might start to increase when Ec.m./VB < 0.95 for both systems.

SIRTUIN 1 AND SIRTUIN 3: PHYSIOLOGICAL MODULATORS OF METABOLISM

PubMed Central

Nogueiras, Ruben; Habegger, Kirk M.; Chaudhary, Nilika; Finan, Brian; Banks, Alexander S.; Dietrich, Marcelo O.; Horvath, Tamas L.; Sinclair, David A.; Pfluger, Paul T.; Tschöop, Matthias H.

2013-01-01

The sirtuins are a family of highly conserved NAD+-dependent deacetylases that act as cellular sensors to detect energy availability and modulate metabolic processes. Two sirtuins that are central to the control of metabolic processes are mammalian sirtuin 1 (SIRT1) and sirtuin 3 (SIRT3), which are localized to the nucleus and mitochondria, respectively. Both are activated by high NAD+ levels, a condition caused by low cellular energy status. By deacetylating a variety of proteins that induce catabolic processes while inhibiting anabolic processes, SIRT1 and SIRT3 coordinately increase cellular energy stores and ultimately maintain cellular energy homeostasis. Defects in the pathways controlled by SIRT1 and SIRT3 are known to result in various metabolic disorders. Consequently, activation of sirtuins by genetic or pharmacological means can elicit multiple metabolic benefits that protect mice from diet-induced obesity, type 2 diabetes, and nonalcoholic fatty liver disease. PMID:22811431

Neural correlates underlying naloxone-induced amelioration of sexual behavior deterioration due to an alarm pheromone

PubMed Central

Kobayashi, Tatsuya; Kiyokawa, Yasushi; Takeuchi, Yukari; Mori, Yuji

2015-01-01

Sexual behavior is suppressed by various types of stressors. We previously demonstrated that an alarm pheromone released by stressed male Wistar rats is a stressor to other rats, increases the number of mounts needed for ejaculation, and decreases the hit rate (described as the number of intromissions/sum of the mounts and intromissions). This deterioration in sexual behavior was ameliorated by pretreatment with the opioid receptor antagonist naloxone. However, the neural mechanism underlying this remains to be elucidated. Here, we examined Fos expression in 31 brain regions of pheromone-exposed rats and naloxone-pretreated pheromone-exposed rats 60 min after 10 intromissions. As previously reported, the alarm pheromone increased the number of mounts and decreased the hit rate. In addition, Fos expression was increases in the anterior medial division (BNSTam), anterior lateral division (BNSTal) and posterior division (BNSTp) of the bed nucleus of the stria terminalis, parvocellular part of the paraventricular nucleus of the hypothalamus, arcuate nucleus, dorsolateral and ventrolateral periaqueductal gray, and nucleus paragigantocellularis (nPGi). Fos expression was decreased in the magnocellular part of the paraventricular nucleus of the hypothalamus. Pretreatment with naloxone blocked the pheromone-induced changes in Fos expression in the magnocellular part of the paraventricular nucleus of the hypothalamus, ventrolateral periaqueductal gray, and nPGi. Based on these results, we hypothesize that the alarm pheromone deteriorated sexual behavior by activating the ventrolateral periaqueductal gray-nucleus paragigantocellularis cluster and suppressing the magnocellular part of the paraventricular nucleus of the hypothalamus (PVN) via the opioidergic pathway. PMID:25755631

Initialization of hydrodynamics in relativistic heavy ion collisions with an energy-momentum transport model

NASA Astrophysics Data System (ADS)

Naboka, V. Yu.; Akkelin, S. V.; Karpenko, Iu. A.; Sinyukov, Yu. M.

2015-01-01

A key ingredient of hydrodynamical modeling of relativistic heavy ion collisions is thermal initial conditions, an input that is the consequence of a prethermal dynamics which is not completely understood yet. In the paper we employ a recently developed energy-momentum transport model of the prethermal stage to study influence of the alternative initial states in nucleus-nucleus collisions on flow and energy density distributions of the matter at the starting time of hydrodynamics. In particular, the dependence of the results on isotropic and anisotropic initial states is analyzed. It is found that at the thermalization time the transverse flow is larger and the maximal energy density is higher for the longitudinally squeezed initial momentum distributions. The results are also sensitive to the relaxation time parameter, equation of state at the thermalization time, and transverse profile of initial energy density distribution: Gaussian approximation, Glauber Monte Carlo profiles, etc. Also, test results ensure that the numerical code based on the energy-momentum transport model is capable of providing both averaged and fluctuating initial conditions for the hydrodynamic simulations of relativistic nuclear collisions.

The neuroanatomical function of leptin in the hypothalamus.

PubMed

van Swieten, M M H; Pandit, R; Adan, R A H; van der Plasse, G

2014-11-01

The anorexigenic hormone leptin plays an important role in the control of food intake and feeding-related behavior, for an important part through its action in the hypothalamus. The adipose-derived hormone modulates a complex network of several intercommunicating orexigenic and anorexigenic neuropeptides in the hypothalamus to reduce food intake and increase energy expenditure. In this review we present an updated overview of the functional role of leptin in respect to feeding and feeding-related behavior per distinct hypothalamic nuclei. In addition to the arcuate nucleus, which is a major leptin sensitive hub, leptin-responsive neurons in other hypothalamic nuclei, including the, dorsomedial-, ventromedial- and paraventricular nucleus and the lateral hypothalamic area, are direct targets of leptin. However, leptin also modulates hypothalamic neurons in an indirect manner, such as via the melanocortin system. The dissection of the complexity of leptin's action on the networks involved in energy balance is subject of recent and future studies. A full understanding of the role of hypothalamic leptin in the regulation of energy balance requires cell-specific manipulation using of conditional deletion and expression of leptin receptors. In addition, optogenetic and pharmacogenetic tools in combination with other pharmacological (such as the recent discovery of a leptin receptor antagonist) and neuronal tracing techniques to map the circuit, will be helpful to understand the role of leptin receptor expressing neurons. Better understanding of these circuits and the involvement of leptin could provide potential sites for therapeutic interventions in obesity and metabolic diseases characterized by dysregulation of energy balance. Copyright © 2014 Elsevier B.V. All rights reserved.

Nuclear Poincaré cycle synchronizes with the incident de Broglie wave to predict regularity in neutron resonance energies

NASA Astrophysics Data System (ADS)

Ohkubo, Makio

2016-06-01

In observed neutron resonances, long believed to be a form of quantum chaos, regular family structures are found in the s-wave resonances of many even-even nuclei in the tens keV to MeV region [M.Ohkubo, Phys. Rev. C 87, 014608(2013)]. Resonance reactions take place when the incident de Broglie wave synchronizes with the Poincaré cycle of the compound nucleus, which is composed of several normal modes with periods that are time quantized by inverse Fermi energy. Based on the breathing model of the compound nucleus, neutron resonance energies in family structures are written by simple arithmetic expressions using Sn and small integers. Family structures in observed resonances of 40Ca+n and 37Cl+n are described as simple cases. A model for time quantization is discussed.

Astrophysical S-Factor of p 7Be Capture at Low Energies

NASA Astrophysics Data System (ADS)

Dubovichenko, S. B.; Burkova, N. A.; Dzhazairov-Kakhramanov, A. V.; Tkachenko, A. S.

2018-04-01

In the modified potential cluster model, the possibility of describing the astrophysical S-factor of radiative p7Be→8Bγ capture to the ground state of the 8B nucleus at energies from 10 keV to 1 MeV is considered. Potentials of intercluster interactions, matched to the spectra of the 8B nucleus for scattering processes, and the potential of the bound 3P2 ground state in the p7Be cluster channel are constructed. The resonance in the 3P1 scattering wave at the energy 0.722 MeV, which leads to an M1-transition to the ground state, is considered. Total cross sections and the reaction rate of p7Be capture are calculated in the temperature range from 0.01·T9 to 5·T9.

On the variations of O III forbidden line intensities in the spectrum of the planetary nebula IC 4997

NASA Astrophysics Data System (ADS)

Egikyan, A. G.

1997-10-01

The causes of asynchronous variations in the intensities of forbidden O III lines in the spectrum of the planetary nebula IC 4997 are considered. It is shown that the strengthening of the 4363-A line with a simultaneous weakening of the N1 and N2 lines can be explained by a severalfold increase of the mass-loss rate from the nucleus, up to 1-2 x 10 exp -7 solar mass/yr, over several years. The ionization model of the nebula under the combined effect of nucleus emission and the emission from a variable hot stellar wind with electron temperature of 500,000 K is used to calculate the theoretical line intensities. The calculations included 12 levels of O III. In the region of O III line formation, the electron density of 10 exp 6/cu cm and Te, which varies from 12,000 to 15,000 K, yield theoretical line intensities that are in best agreement with observations. The X-ray luminosity of the stellar wind from the nucleus at energies not less than 0.2 keV is on the order of 10 exp 35 erg/s, but the interstellar extinction rules out the possibility of observing this object.

Energy imbalance alters Ca2+ handling and excitability of POMC neurons

PubMed Central

Paeger, Lars; Pippow, Andreas; Hess, Simon; Paehler, Moritz; Klein, Andreas C; Husch, Andreas; Pouzat, Christophe; Brüning, Jens C; Kloppenburg, Peter

2017-01-01

Satiety-signaling, pro-opiomelanocortin (POMC)-expressing neurons in the arcuate nucleus of the hypothalamus play a pivotal role in the regulation of energy homeostasis. Recent studies reported altered mitochondrial dynamics and decreased mitochondria- endoplasmic reticulum contacts in POMC neurons during diet-induced obesity. Since mitochondria play a crucial role in Ca2+ signaling, we investigated whether obesity alters Ca2+ handling of these neurons in mice. In diet-induced obesity, cellular Ca2+ handling properties including mitochondrial Ca2+ uptake capacity are impaired, and an increased resting level of free intracellular Ca2+ is accompanied by a marked decrease in neuronal excitability. Experimentally increasing or decreasing intracellular Ca2+ concentrations reproduced electrophysiological properties observed in diet-induced obesity. Taken together, we provide the first direct evidence for a diet-dependent deterioration of Ca2+ homeostasis in POMC neurons during obesity development resulting in impaired function of these critical energy homeostasis-regulating neurons. DOI: http://dx.doi.org/10.7554/eLife.25641.001 PMID:28762947

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kopeliovich, B. Z.; Institut fuer Theoretische Physik der Universitaet, Philosophenweg 19, D-69120 Heidelberg; Potashnikova, I. K.

Two novel QCD effects, double-color filtering and mutual boosting of the saturation scales in colliding nuclei, affect the transparency of the nuclei for quark dipoles in comparison with proton-nucleus collisions. The former effect increases the survival probability of the dipoles, since color filtering in one nucleus makes the other one more transparent. The second effect acts in the opposite direction and is stronger; it makes the colliding nuclei more opaque than in the case of pA collisions. As a result of parton saturation in nuclei the effective scale is shifted upward, which leads to an increase of the gluon densitymore » at small x. This in turn leads to a stronger transverse momentum broadening in AA compared with pA collisions, i.e., to an additional growth of the saturation momentum. Such a mutual boosting leads to a system of reciprocity equations, which result in a saturation scale, a few times higher in AA than in pA collisions at the energies of the large hadron collider (LHC). Since the dipole cross section is proportional to the saturation momentum squared, the nuclei become much more opaque for dipoles in AA than in pA collisions. For the same reason gluon shadowing turns out to be boosted to a larger magnitude compared with the product of the gluon shadowing factors in each of the colliding nuclei. All these effects make it more difficult to establish a baseline for anomalous J/{Psi} suppression in heavy ion collisions at high energies.« less

CONCERNING THE PROBLEM OF THE SYSTEMATIZATION OF $beta$ SPECTRA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Seidl, R.

1956-01-01

S>From data on the energy liberated during KB capture or ing BETA decay, the problem of the construction of a shell model of the nucleus is considered. It is proposed at the BETA transition is carried out by the last particle in the shell. The neutron and proton levels are considered individually. It is stated, that on the basis of the data on topes and the values of the nuclear spins. To obtain agreement with the nuclear binding energies and the data on nuclear reactions, it becomes necessary to propose that the transition of each nucleon causes a lowering ofmore » the bottom of the potentisl well of the nucleus.« less

Glucokinase activity in the arcuate nucleus regulates glucose intake

PubMed Central

Hussain, Syed; Richardson, Errol; Ma, Yue; Holton, Christopher; De Backer, Ivan; Buckley, Niki; Dhillo, Waljit; Bewick, Gavin; Zhang, Shuai; Carling, David; Bloom, Steve; Gardiner, James

2014-01-01

The brain relies on a constant supply of glucose, its primary fuel, for optimal function. A taste-independent mechanism within the CNS that promotes glucose delivery to the brain has been postulated to maintain glucose homeostasis; however, evidence for such a mechanism is lacking. Here, we determined that glucokinase activity within the hypothalamic arcuate nucleus is involved in regulation of dietary glucose intake. In fasted rats, glucokinase activity was specifically increased in the arcuate nucleus but not other regions of the hypothalamus. Moreover, pharmacologic and genetic activation of glucokinase in the arcuate nucleus of rodent models increased glucose ingestion, while decreased arcuate nucleus glucokinase activity reduced glucose intake. Pharmacologic targeting of potential downstream glucokinase effectors revealed that ATP-sensitive potassium channel and P/Q calcium channel activity are required for glucokinase-mediated glucose intake. Additionally, altered glucokinase activity affected release of the orexigenic neurotransmitter neuropeptide Y in response to glucose. Together, our results suggest that glucokinase activity in the arcuate nucleus specifically regulates glucose intake and that appetite for glucose is an important driver of overall food intake. Arcuate nucleus glucokinase activation may represent a CNS mechanism that underlies the oft-described phenomena of the “sweet tooth” and carbohydrate craving. PMID:25485685

Large area emulsion chamber experiments for the Space Shuttle

NASA Technical Reports Server (NTRS)

Parnell, T. A.

1985-01-01

Emulsion-chamber experiments employing nuclear-track emulsions, etchable plastic detectors, metal plates, and X-ray films continue to demonstrate high productivity and potential in the study of cosmic-ray primaries and their interactions. Emulsions, with unsurpassed track-recording capability, provide an appropriate medium for the study of nucleus-nucleus interactions at high energy, which will likely produce observations of a phase change in nuclear matter. The many advantages of emulsion chambers (excellent multitrack recording capability, large geometry factor, low apparatus cost, simplicity of design and construction) are complemented by the major advantages of the Space Shuttle as an experiment carrier. A Shuttle experiment which could make a significant advance in both cosmic-ray primary and nucleus-nucleus interaction studies is described. Such an experiment would serve as a guide for use of emulsions during the Space Station era. Some practical factors that must be considered in planning a Shuttle exposure of emulsion chambers are discussed.

Surface-peaked medium effects in the interaction of nucleons with finite nuclei

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aguayo, F. J.; Arellano, H. F.

We investigate the asymptotic separation of the optical model potential for nucleon-nucleus scattering in momentum space, where the potential is split into a medium-independent term and another depending exclusively on the gradient of the density-dependent g matrix. This decomposition confines the medium sensitivity of the nucleon-nucleus coupling to the surface of the nucleus. We examine this feature in the context of proton-nucleus scattering at beam energies between 30 and 100 MeV and find that the pn coupling accounts for most of this sensitivity. Additionally, based on this general structure of the optical potential we are able to treat both, themore » medium dependence of the effective interaction and the full mixed density as described by single-particle shell models. The calculated scattering observables agree within 10% with those obtained by Arellano, Brieva, and Love in their momentum-space g-folding approach.« less

Differential response of TRHergic neurons of the hypothalamic paraventricular nucleus (PVN) in female animals submitted to food-restriction or dehydration-induced anorexia and cold exposure.

PubMed

Jaimes-Hoy, Lorraine; Joseph-Bravo, Patricia; de Gortari, Patricia

2008-02-01

TRH neurons of the hypothalamic paraventricular nucleus (PVN), regulate pituitary-thyroid axis (HPT). Fasting activates expression of orexigenic peptides from the arcuate nucleus, increases corticosterone while reduces leptin, and pro-TRH mRNA levels despite low serum thyroid hormone concentration (tertiary hypothyroidism). TRH synthesis is positively regulated by anorexigenic peptides whose expression is reduced in fasting. The model of dehydration-induced anorexia (DIA) leads to decreased voluntary food intake but peptide expression in the arcuate is similar to forced-food restriction (FFR), where animals remain hungered. We compared the response of HPT axis of female Wistar rats submitted to DIA (2.5% saline solution, food ad libitum, 7 days) with FFR (provided with the amount of food ingested by DIA) and naïve (N) group fed ad libitum, as well as their response to acute cold exposure. Pro-TRH and pro-CRH mRNA levels in the PVN were measured by RT-PCR, TRH content, serum concentration of TSH and thyroid hormones by radioimmunoassay. DIA rats reduced 80% their food consumption compared to N, decreased PVN pro-CRH expression, serum estradiol and leptin levels, increased corticosterone similar to FFR. HPT axis of DIA animals failed to adapt: FFR presented tertiary hypothyroidism and DIA, primary. Response to cold stimulation leading to increased pro-TRH mRNA levels and TRH release was preserved under reduced energy availability in FFR rats but not in DIA, although the dynamics of hormonal release differed: TSH release augmented only in naïve; thyroxine in all but highest in DIA, and triiodothyronine in FFR and DIA suggesting a differential regulation of deiodinases.

GLP-1 Receptor Stimulation of the Lateral Parabrachial Nucleus Reduces Food Intake: Neuroanatomical, Electrophysiological, and Behavioral Evidence

PubMed Central

Richard, Jennifer E.; Farkas, Imre; Anesten, Fredrik; Anderberg, Rozita H.; Dickson, Suzanne L.; Gribble, Fiona M.; Reimann, Frank; Jansson, John-Olov; Liposits, Zsolt

2014-01-01

The parabrachial nucleus (PBN) is a key nucleus for the regulation of feeding behavior. Inhibitory inputs from the hypothalamus to the PBN play a crucial role in the normal maintenance of feeding behavior, because their loss leads to starvation. Viscerosensory stimuli result in neuronal activation of the PBN. However, the origin and neurochemical identity of the excitatory neuronal input to the PBN remain largely unexplored. Here, we hypothesize that hindbrain glucagon-like peptide 1 (GLP-1) neurons provide excitatory inputs to the PBN, activation of which may lead to a reduction in feeding behavior. Our data, obtained from mice expressing the yellow fluorescent protein in GLP-1-producing neurons, revealed that hindbrain GLP-1-producing neurons project to the lateral PBN (lPBN). Stimulation of lPBN GLP-1 receptors (GLP-1Rs) reduced the intake of chow and palatable food and decreased body weight in rats. It also activated lPBN neurons, reflected by an increase in the number of c-Fos-positive cells in this region. Further support for an excitatory role of GLP-1 in the PBN is provided by electrophysiological studies showing a remarkable increase in firing of lPBN neurons after Exendin-4 application. We show that within the PBN, GLP-1R activation increased gene expression of 2 energy balance regulating peptides, calcitonin gene-related peptide (CGRP) and IL-6. Moreover, nearly 70% of the lPBN GLP-1 fibers innervated lPBN CGRP neurons. Direct intra-lPBN CGRP application resulted in anorexia. Collectively, our molecular, anatomical, electrophysiological, pharmacological, and behavioral data provide evidence for a functional role of the GLP-1R for feeding control in the PBN. PMID:25116706

Effects of systemic L-tyrosine on dopamine release from rat corpus striatum and nucleus accumbens

NASA Technical Reports Server (NTRS)

During, Matthew J.; Acworth, Ian N.; Wurtman, Richard J.

1988-01-01

Intracerebral dialysis was used to monitor extracellular fluid from rat striatum and nucleus accumbens following the intraperitoneal administration of tyrosine. Dopamine concentrations in dialysates from both the striatum and the nucleus accumbens increased significantly in response to the tyrosine. The magnitude of the tyrosine effect was greater in the nucleus accumbens than in the striatum. Hence, mesolimbic dopaminergic neurons may be especially responsive to precursor availability.

Comparison of exact solution with Eikonal approximation for elastic heavy ion scattering

NASA Technical Reports Server (NTRS)

Dubey, Rajendra R.; Khandelwal, Govind S.; Cucinotta, Francis A.; Maung, Khin Maung

1995-01-01

A first-order optical potential is used to calculate the total and absorption cross sections for nucleus-nucleus scattering. The differential cross section is calculated by using a partial-wave expansion of the Lippmann-Schwinger equation in momentum space. The results are compared with solutions in the Eikonal approximation for the equivalent potential and with experimental data in the energy range from 25A to 1000A MeV.

Eikonal Scattering in the sdg Interacting Boson Model:. Analytical Results in the SUsdg(3) Limit and Their Generalizations

NASA Astrophysics Data System (ADS)

Kota, V. K. B.

General expression for the representation matrix elements in the SUsdg(3) limit of the sdg interacting boson model (sdgIBM) is derived that determine the scattering amplitude in the eikonal approximation for medium energy proton-nucleus scattering when the target nucleus is deformed and it is described by the SUsdg(3) limit. The SUsdg(3) result is generalized to two important situations: (i) when the target nucleus ground band states are described as states arising out of angular momentum projection from a general single Kπ = 0+ intrinsic state in sdg space; (ii) for rotational bands built on one-phonon excitations in sdgIBM.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lappi, T.; Schenke, B.; Schlichting, S.

Here we examine the origins of azimuthal correlations observed in high energy proton-nucleus collisions by considering the simple example of the scattering of uncorrelated partons off color fields in a large nucleus. We demonstrate how the physics of fluctuating color fields in the color glass condensate (CGC) effective theory generates these azimuthal multiparticle correlations and compute the corresponding Fourier coefficients v n within different CGC approximation schemes. We discuss in detail the qualitative and quantitative differences between the different schemes. Lastly, we will show how a recently introduced color field domain model that captures key features of the observed azimuthalmore » correlations can be understood in the CGC effective theory as a model of non-Gaussian correlations in the target nucleus.« less

Galaxy IC 3639 with Obscured Active Galactic Nucleus

NASA Image and Video Library

2017-01-07

IC 3639, a galaxy with an active galactic nucleus, is seen in this image combining data from the Hubble Space Telescope and the European Southern Observatory. This galaxy contains an example of a supermassive black hole hidden by gas and dust. Researchers analyzed NuSTAR data from this object and compared them with previous observations from NASA's Chandra X-Ray Observatory and the Japanese-led Suzaku satellite. The findings from NuSTAR, which is more sensitive to higher energy X-rays than these observatories, confirm the nature of IC 3639 as an active galactic nucleus that is heavily obscured, and intrinsically much brighter than observed. http://photojournal.jpl.nasa.gov/catalog/PIA21087

Recent Results and the Future of the NA61/SHINE Strong Interactions Program

NASA Astrophysics Data System (ADS)

Łysakowski, B.

NA61/SHINE is a fixed target experiment at the CERN Super-Proton- Synchrotron. The main goals of the experiment are to discover the critical point of strongly interacting matter and study the properties of the onset of deconfnement. In order to reach these goals the collaboration studies hadron production properties in nucleus-nucleus, proton-proton and proton-nucleus interactions. In this talk, recent results on particle production in p+p interactions, as well as Be+Be and Ar+Sc collisions in the SPS energy range are reviewed. The results are compared with available world data. The future of the NA61/SHINE scientifc program is also presented.

Food intake reductions and increases in energetic responses by hindbrain leptin and melanotan II are enhanced in mice with POMC-specific PTP1B deficiency.

PubMed

De Jonghe, Bart C; Hayes, Matthew R; Zimmer, Derek J; Kanoski, Scott E; Grill, Harvey J; Bence, Kendra K

2012-09-01

Leptin regulates energy balance through central circuits that control food intake and energy expenditure, including proopiomelanocortin (POMC) neurons. POMC neuron-specific deletion of protein tyrosine phosphatase 1B (PTP1B) (Ptpn1(loxP/loxP) POMC-Cre), a negative regulator of CNS leptin signaling, results in resistance to diet-induced obesity and improved peripheral leptin sensitivity in mice, thus establishing PTP1B as an important component of POMC neuron regulation of energy balance. POMC neurons are expressed in the pituitary, the arcuate nucleus of the hypothalamus (ARH), and the nucleus of the solitary tract (NTS) in the hindbrain, and it is unknown how each population might contribute to the phenotype of POMC-Ptp1b(-/-) mice. It is also unknown whether improved leptin sensitivity in POMC-Ptp1b(-/-) mice involves altered melanocortin receptor signaling. Therefore, we examined the effects of hindbrain administration (4th ventricle) of leptin (1.5, 3, and 6 μg) or the melanocortin 3/4R agonist melanotan II (0.1 and 0.2 nmol) in POMC-Ptp1b(-/-) (KO) and control PTP1B(fl/fl) (WT) mice on food intake, body weight, spontaneous physical activity (SPA), and core temperature (T(C)). The results show that KO mice were hypersensitive to hindbrain leptin- and MTII-induced food intake and body weight suppression and SPA compared with WT mice. Greater increases in leptin- but not MTII-induced T(C) were also observed in KO vs. WT animals. In addition, KO mice displayed elevated hindbrain and hypothalamic MC4R mRNA expression. These studies are the first to show that hindbrain administration of leptin or a melanocortin receptor agonist alters energy balance in mice likely via participation of hindbrain POMC neurons.

Characterization of the Variability of Nucleoli in the Cells of Panax ginseng Meyer In Vivo and In Vitro.

PubMed

Khrolenko, Yuliya A; Burundukova, Olga L; Lauve, Lyudmila S; Muzarok, Tamara I; Makhan'kov, Vyacheslav V; Zhuravlev, Yuri N

2012-07-01

Results of karyological study of intact plants and some callus lines of Panax ginseng are presented. In the native plants of P. ginseng the nucleus with 1 nucleolus (90%) dominate, and nucleus with 2 nucleoli is rare. One nucleolar nucleus also dominate in interphase nuclei of cells of cultivated P. ginseng (from 2006), but we also found nucleus with 2 to 3 nucleoli in the same cell lines. Interphase nuclei of P. ginseng in long cultivated lines (from 1988) contain 1 to 9 nucleoli, with a predominance of nuclei containing from 3 to 4 nucleoli. It was shown that long-time cells (cultivated since 1988) had cytogenetic changes such as increase level of polyploid and aneuploid cells, increase of nucleoli number into interphase nucleus and decrease of nuclei/nucleoli ratio. These long-time cultivated cells had very low ginsenoside content.

Characterization of the Variability of Nucleoli in the Cells of Panax ginseng Meyer In Vivo and In Vitro

PubMed Central

Khrolenko, Yuliya A.; Burundukova, Olga L.; Lauve, Lyudmila S.; Muzarok, Tamara I.; Makhan’kov, Vyacheslav V.; Zhuravlev, Yuri N.

2012-01-01

Results of karyological study of intact plants and some callus lines of Panax ginseng are presented. In the native plants of P. ginseng the nucleus with 1 nucleolus (90%) dominate, and nucleus with 2 nucleoli is rare. One nucleolar nucleus also dominate in interphase nuclei of cells of cultivated P. ginseng (from 2006), but we also found nucleus with 2 to 3 nucleoli in the same cell lines. Interphase nuclei of P. ginseng in long cultivated lines (from 1988) contain 1 to 9 nucleoli, with a predominance of nuclei containing from 3 to 4 nucleoli. It was shown that long-time cells (cultivated since 1988) had cytogenetic changes such as increase level of polyploid and aneuploid cells, increase of nucleoli number into interphase nucleus and decrease of nuclei/nucleoli ratio. These long-time cultivated cells had very low ginsenoside content. PMID:23717134

Geometry Survey of the Time-of-Flight Neutron-Elastic Scattering (Antonella) Experiment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oshinowo, Babatunde O.; Izraelevitch, Federico

The Antonella experiment is a measurement of the ionization efficiency of nuclear recoils in silicon at low energies [1]. It is a neutron elastic scattering experiment motivated by the search for dark matter particles. In this experiment, a proton beam hits a lithium target and neutrons are produced. The neutron shower passes through a collimator that produces a neutron beam. The beam illuminates a silicon detector. With a certain probability, a neutron interacts with a silicon nucleus of the detector producing elastic scattering. After the interaction, a fraction of the neutron energy is transferred to the silicon nucleus which acquiresmore » kinetic energy and recoils. This kinetic energy is then dissipated in the detector producing ionization and thermal energy. The ionization produced is measured with the silicon detector electronics. On the other hand, the neutron is scattered out of the beam. A neutron-detector array (made of scintillator bars) registers the neutron arrival time and the scattering angle to reconstruct the kinematics of the neutron-nucleus interaction with the time-of-flight technique [2]. In the reconstruction equations, the energy of the nuclear recoil is a function of the scattering angle with respect to the beam direction, the time-of-flight of the neutron and the geometric distances between components of the setup (neutron-production target, silicon detector, scintillator bars). This paper summarizes the survey of the different components of the experiment that made possible the off-line analysis of the collected data. Measurements were made with the API Radian Laser Tracker and I-360 Probe Wireless. The survey was completed at the University of Notre Dame, Indiana, USA in February 2015.« less

Differential Effects of Two Fermentable Carbohydrates on Central Appetite Regulation and Body Composition

PubMed Central

Gibson, Glenn R.; Tuohy, Kieran M.; Sharma, Raj Kumar; Swann, Jonathan R.; Deaville, Eddie R.; Sleeth, Michele L.; Thomas, E. Louise; Holmes, Elaine; Bell, Jimmy D.; Frost, Gary

2012-01-01

Background Obesity is rising at an alarming rate globally. Different fermentable carbohydrates have been shown to reduce obesity. The aim of the present study was to investigate if two different fermentable carbohydrates (inulin and β-glucan) exert similar effects on body composition and central appetite regulation in high fat fed mice. Methodology/Principal Findings Thirty six C57BL/6 male mice were randomized and maintained for 8 weeks on a high fat diet containing 0% (w/w) fermentable carbohydrate, 10% (w/w) inulin or 10% (w/w) β-glucan individually. Fecal and cecal microbial changes were measured using fluorescent in situ hybridization, fecal metabolic profiling was obtained by proton nuclear magnetic resonance (1H NMR), colonic short chain fatty acids were measured by gas chromatography, body composition and hypothalamic neuronal activation were measured using magnetic resonance imaging (MRI) and manganese enhanced MRI (MEMRI), respectively, PYY (peptide YY) concentration was determined by radioimmunoassay, adipocyte cell size and number were also measured. Both inulin and β-glucan fed groups revealed significantly lower cumulative body weight gain compared with high fat controls. Energy intake was significantly lower in β-glucan than inulin fed mice, with the latter having the greatest effect on total adipose tissue content. Both groups also showed an increase in the numbers of Bifidobacterium and Lactobacillus-Enterococcus in cecal contents as well as feces. β- glucan appeared to have marked effects on suppressing MEMRI associated neuronal signals in the arcuate nucleus, ventromedial hypothalamus, paraventricular nucleus, periventricular nucleus and the nucleus of the tractus solitarius, suggesting a satiated state. Conclusions/Significance Although both fermentable carbohydrates are protective against increased body weight gain, the lower body fat content induced by inulin may be metabolically advantageous. β-glucan appears to suppress neuronal activity in the hypothalamic appetite centers. Differential effects of fermentable carbohydrates open new possibilities for nutritionally targeting appetite regulation and body composition. PMID:22952656

X-Ray Variability Characteristics of the Seyfert 1 Galaxy NGC 3783

NASA Astrophysics Data System (ADS)

Markowitz, A.

2005-12-01

We have characterized the energy-dependent X-ray variability properties of the Seyfert 1 galaxy NGC 3783 using archival XMM-Newton and Rossi X-Ray Timing Explorer data. The high-frequency fluctuation power spectral density function (PSD) slope is consistent with flattening toward higher energies. Light-curve cross-correlation functions yield no significant lags, but peak coefficients generally decrease as energy separation of the bands increases on both short and long timescales. We have measured the coherence between various X-ray bands over the temporal frequency range of 6×10-8-1×10-4 Hz; this range includes the temporal frequency of the low-frequency PSD break tentatively detected by Markowitz et al. and includes the lowest temporal frequency over which coherence has been measured in any active galactic nucleus to date. Coherence is generally near unity at these temporal frequencies, although it decreases slightly as energy separation of the bands increases. Temporal frequency-dependent phase lags are detected on short timescales; phase lags are consistent with increasing as energy separation increases or as temporal frequency decreases. All of these results are similar to those obtained previously for several Seyfert galaxies and stellar mass black hole systems. Qualitatively, these results are consistent with the variability models of Kotov et al. and Lyubarskii, wherein the X-ray variability is due to inwardly propagating variations in the local mass accretion rate.

Random-matrix approach to the statistical compound nuclear reaction at low energies using the Monte-Carlo technique [PowerPoint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kawano, Toshihiko

2015-11-10

This theoretical treatment of low-energy compound nucleus reactions begins with the Bohr hypothesis, with corrections, and various statistical theories. The author investigates the statistical properties of the scattering matrix containing a Gaussian Orthogonal Ensemble (GOE) Hamiltonian in the propagator. The following conclusions are reached: For all parameter values studied, the numerical average of MC-generated cross sections coincides with the result of the Verbaarschot, Weidenmueller, Zirnbauer triple-integral formula. Energy average and ensemble average agree reasonably well when the width I is one or two orders of magnitude larger than the average resonance spacing d. In the strong-absorption limit, the channel degree-of-freedommore » ν a is 2. The direct reaction increases the inelastic cross sections while the elastic cross section is reduced.« less

Hypothalamic Vitamin D Improves Glucose Homeostasis and Reduces Weight

PubMed Central

Arble, Deanna M.; Chambers, Adam P.; Gutierrez-Aguilar, Ruth; He, Yanlin; Xu, Yong; Gardner, David; Moore, David D.; Seeley, Randy J.; Sandoval, Darleen A.

2016-01-01

Despite clear associations between vitamin D deficiency and obesity and/or type 2 diabetes, a causal relationship is not established. Vitamin D receptors (VDRs) are found within multiple tissues, including the brain. Given the importance of the brain in controlling both glucose levels and body weight, we hypothesized that activation of central VDR links vitamin D to the regulation of glucose and energy homeostasis. Indeed, we found that small doses of active vitamin D, 1α,25-dihydroxyvitamin D3 (1,25D3) (calcitriol), into the third ventricle of the brain improved glucose tolerance and markedly increased hepatic insulin sensitivity, an effect that is dependent upon VDR within the paraventricular nucleus of the hypothalamus. In addition, chronic central administration of 1,25D3 dramatically decreased body weight by lowering food intake in obese rodents. Our data indicate that 1,25D3-mediated changes in food intake occur through action within the arcuate nucleus. We found that VDR colocalized with and activated key appetite-regulating neurons in the arcuate, namely proopiomelanocortin neurons. Together, these findings define a novel pathway for vitamin D regulation of metabolism with unique and divergent roles for central nervous system VDR signaling. Specifically, our data suggest that vitamin D regulates glucose homeostasis via the paraventricular nuclei and energy homeostasis via the arcuate nuclei. PMID:27217488

DOE Office of Scientific and Technical Information (OSTI.GOV)

Akkelin, S.V.; Sinyukov, Yu.M.

A method allowing analysis of the overpopulation of phase space in heavy ion collisions in a model-independent way is proposed within the hydrodynamic approach. It makes it possible to extract a chemical potential of thermal pions at freeze-out, irrespective of the form of freeze-out (isothermal) hypersurface in Minkowski space and transverse flows on it. The contributions of resonance (with masses up to 2 GeV) decays to spectra, interferometry volumes, and phase-space densities are calculated and discussed in detail. The estimates of average phase-space densities and chemical potentials of thermal pions are obtained for SPS and RHIC energies. They demonstrate thatmore » multibosonic phenomena at those energies might be considered as a correction factor rather than as a significant physical effect. The analysis of the evolution of the pion average phase-space density in chemically frozen hadron systems shows that it is almost constant or slightly increases with time while the particle density and phase-space density at each space point decreases rapidly during the system's expansion. We found that, unlike the particle density, the average phase-space density has no direct link to the freeze-out criterion and final thermodynamic parameters, being connected rather to the initial phase-space density of hadronic matter formed in relativistic nucleus-nucleus collisions.« less

Radiative lifetime and energy of the low-energy isomeric level in 229Th

NASA Astrophysics Data System (ADS)

Tkalya, E. V.; Schneider, Christian; Jeet, Justin; Hudson, Eric R.

2015-11-01

We estimate the range of the radiative lifetime and energy of the anomalous, low-energy 3 /2+(7.8 ±0.5 eV) state in the 229Th nucleus. Our phenomenological calculations are based on the available experimental data for the intensities of M 1 and E 2 transitions between excited levels of the 229Th nucleus in the Kπ[N nZΛ ] =5 /2+[633 ] and 3 /2+[631 ] rotational bands. We also discuss the influence of certain branching coefficients, which affect the currently accepted measured energy of the isomeric state. From this work, we establish a favored region, 0.66 ×106seV3/ω3≤τ ≤2.2 ×106seV3/ω3 , where the transition lifetime τ as a function of transition energy ω should lie at roughly the 95% confidence level. Together with the result of Beck et al. [LLNL-PROC-415170 (2009)], we establish a favored area where transition lifetime and energy should lie at roughly the 90% confidence level. We also suggest new nuclear physics measurements, which would significantly reduce the ambiguity in the present data.

Retention of Gadolinium-Based Contrast Agents in Multiple Sclerosis: Retrospective Analysis of an 18-Year Longitudinal Study.

PubMed

Forslin, Y; Shams, S; Hashim, F; Aspelin, P; Bergendal, G; Martola, J; Fredrikson, S; Kristoffersen-Wiberg, M; Granberg, T

2017-07-01

Gadolinium-based contrast agents have been associated with lasting high T1-weighted signal intensity in the dentate nucleus and globus pallidus, with histopathologically confirmed gadolinium retention. We aimed to longitudinally investigate the relationship of multiple gadolinium-based contrast agent administrations to the Signal Intensity Index in the dentate nucleus and globus pallidus and any associations with cognitive function in multiple sclerosis. The Signal Intensity Index in the dentate nucleus and globus pallidus was retrospectively evaluated on T1-weighted MR imaging in an 18-year longitudinal cohort study of 23 patients with MS receiving multiple gadolinium-based contrast agent administrations and 23 healthy age- and sex-matched controls. Participants also underwent comprehensive neuropsychological testing. Patients with MS had a higher Signal Intensity Index in the dentate nucleus ( P < .001), but not in the globus pallidus ( P = .19), compared with non-gadolinium-based contrast agent-exposed healthy controls by an unpaired t test. Increasing numbers of gadolinium-based contrast agent administrations were associated with an increased Signal Intensity Index in the dentate nucleus (β = 0.45, P < .001) and globus pallidus (β = 0.60, P < .001). This association remained stable with corrections for the age, disease duration, and physical disability for both the dentate nucleus (β = 0.43, P = .001) and globus pallidus (β = 0.58, P < .001). An increased Signal Intensity Index in the dentate nucleus among patients with MS was associated with lower verbal fluency scores, which remained significant after correction for several aspects of disease severity (β = -0.40 P = .013). Our data corroborate previous reports of lasting gadolinium retention in brain tissues. An increased Signal Intensity Index in the dentate nucleus and globus pallidus was associated with lower verbal fluency, which does not prove causality but encourages further studies on cognition and gadolinium-based contrast agent administration. © 2017 by American Journal of Neuroradiology.

Effect of novel atypical antipsychotic, blonanserin, on extracellular neurotransmitter level in rat prefrontal cortex.

PubMed

Ohoyama, Keiko; Yamamura, Satoshi; Hamaguchi, Tatsuya; Nakagawa, Masanori; Motomura, Eishi; Shiroyama, Takashi; Tanii, Hisashi; Okada, Motohiro

2011-02-25

To clarify the mechanisms of action of blonanserin, an atypical antipsychotic drug, we studied the effects of systemic administration of blonanserin and risperidone on extracellular levels of norepinephrine, dopamine, serotonin, GABA and glutamate in the medial prefrontal cortex using microdialysis, and neuronal firing in the ventral tegmental area, locus coeruleus, dorsal raphe nucleus and mediodorsal thalamic nucleus using radiotelemetry. The binding affinities of blonanserin to D(2) and 5-HT(2A) receptors in the rat brain were confirmed and found to be similar. Blonanserin transiently increased neuronal firing in locus coeruleus and ventral tegmental area but not in dorsal raphe nucleus or mediodorsal thalamic nucleus, whereas risperidone increased the firing in locus coeruleus, ventral tegmental area and dorsal raphe nucleus but not in mediodorsal thalamic nucleus. Blonanserin persistently increased frontal extracellular levels of norepinephrine and dopamine but not serotonin, GABA or glutamate, whereas risperidone persistently increased those of norepinephrine, dopamine and serotonin but not GABA or glutamate. These results suggest a pharmacological correlation between the stimulatory effects of these antipsychotics on frontal monoamine release and neuronal activity in monoaminergic nuclei. Inhibition of the α(2) adrenoceptor increased extracellular monoamine levels and enhanced blonanserin-induced increase in extracellular serotonin level. These results indicated that the combination of antagonism of D(2) and 5-HT(2A) receptors contribute to the rise in extracellular levels of norepinephrine and dopamine, and that α(2) adrenoceptors play important roles in frontal serotonin release. They also suggest that blonanserin-induced activation of monoaminergic transmission could be, at least partially, involved in atypical antipsychotic properties of blonanserin. Copyright © 2010 Elsevier B.V. All rights reserved.

Hartree-Fock implementation using a Laguerre-based wave function for the ground state and correlation energies of two-electron atoms.

PubMed

King, Andrew W; Baskerville, Adam L; Cox, Hazel

2018-03-13

An implementation of the Hartree-Fock (HF) method using a Laguerre-based wave function is described and used to accurately study the ground state of two-electron atoms in the fixed nucleus approximation, and by comparison with fully correlated (FC) energies, used to determine accurate electron correlation energies. A variational parameter A is included in the wave function and is shown to rapidly increase the convergence of the energy. The one-electron integrals are solved by series solution and an analytical form is found for the two-electron integrals. This methodology is used to produce accurate wave functions, energies and expectation values for the helium isoelectronic sequence, including at low nuclear charge just prior to electron detachment. Additionally, the critical nuclear charge for binding two electrons within the HF approach is calculated and determined to be Z HF C =1.031 177 528.This article is part of the theme issue 'Modern theoretical chemistry'. © 2018 The Author(s).

Electrical Coupling: Novel Mechanism for Sleep-Wake Control

PubMed Central

Garcia-Rill, Edgar; Heister, David S.; Ye, Meijun; Charlesworth, Amanda; Hayar, Abdallah

2007-01-01

Study Objectives: Recent evidence suggests that certain anesthetic agents decrease electrical coupling, whereas the stimulant modafinil appears to increase electrical coupling. We investigated the potential role of electrical coupling in 2 reticular activating system sites, the subcoeruleus nucleus and in the pedunculopontine nucleus, which has been implicated in the modulation of arousal via ascending cholinergic activation of intralaminar thalamus and descending activation of the subcoeruleus nucleus to generate some of the signs of rapid eye movement sleep. Design: We used 6- to 30-day-old rat pups to obtain brainstem slices to perform whole-cell patch-clamp recordings. Measurements and Results: Recordings from single cells revealed the presence of spikelets, manifestations of action potentials in coupled cells, and of dye coupling of neurons in the pedunculopontine nucleus. Recordings in pairs of pedunculopontine nucleus and subcoeruleus nucleus neurons revealed that some of these were electrically coupled with coupling coefficients of approximately 2%. After blockade of fast synaptic transmission, the cholinergic agonist carbachol was found to induce rhythmic activity in pedunculopontine nucleus and subcoeruleus nucleus neurons, an effect eliminated by the gap junction blockers carbenoxolone or mefloquine. The stimulant modafinil was found to decrease resistance in neurons in the pedunculopontine nucleus and subcoeruleus nucleus after fast synaptic blockade, indicating that the effect may be due to increased coupling. Conclusions: The finding of electrical coupling in specific reticular activating system cell groups supports the concept that this underlying process behind specific neurotransmitter interactions modulates ensemble activity across cell populations to promote changes in sleep-wake state. Citation: Garcia-Rill E; Heister DS; Ye M; Charlesworth A; Hayar A. Electrical coupling: novel mechanism for sleep-wake control. SLEEP 2007;30(11):1405-1414. PMID:18041475

The structure of motion in a 4-component galaxy mass model

NASA Astrophysics Data System (ADS)

Caranicolas, N. D.

1996-03-01

We use a composite galaxy model consisting of a disk-halo, bulge, nucleus and dark-halo components in order to investigate the motion of stars in ther-z plane. It is observed that high angular momentum stars move in regular orbits. The majority of orbits are box orbits. There are also banana-like orbits. For a given value of energy, only a fraction of the low angular momentum stars — those going near the nucleus — show chaotic motion while the rest move in regular orbits. Again one observes the above two kinds of orbits. In addition to the above one can also see orbits with the characteristics of the 2/3 and 3/4 resonance. It is also shown that, in the absence of the bulge component, the area of chaotic motion in the surface of section increases, significantly. This suggests that a larger number of low angular momentum stars are in chaotic orbits in galaxies with massive nuclei and no bulge components.

Measurement of key resonances for the 24Al(p ,γ )25Si reaction rate using in-beam γ -ray spectroscopy

NASA Astrophysics Data System (ADS)

Longfellow, B.; Gade, A.; Brown, B. A.; Richter, W. A.; Bazin, D.; Bender, P. C.; Bowry, M.; Elman, B.; Lunderberg, E.; Weisshaar, D.; Williams, S. J.

2018-05-01

Energy levels and branching ratios for the rp-process nucleus 25Si were determined from the reactions 9Be(26Si,25Si)X and 9Be(25Al,25Si)X using in-beam γ -ray spectroscopy with both high-efficiency and high-resolution detector arrays. Proton-unbound states at 3695(14) and 3802(11) keV were identified and assigned tentative spins and parities based on comparison to theory and the mirror nucleus. The 24Al(p ,γ )25Si reaction rate was calculated using the experimental states and states from charge-dependent USDA and USDB shell-model calculations with downward shifts of the 1 s1 /2 proton orbital to account for the observed Thomas-Ehrman shift, leading to a factor of 10-100 increase in rate for the temperature region of 0.22 GK as compared to a previous calculation. These shifts may be applicable to neighboring nuclei, impacting the proton capture rates in this region of the chart.

Trace element abundance determinations by Synchrotron X Ray Fluorescence (SXRF) on returned comet nucleus mineral grains

NASA Technical Reports Server (NTRS)

Flynn, G. J.; Sutton, S. R.

1989-01-01

Trace element analyses were performed on bulk cosmic dust particles by Proton Induced X Ray Emission (PIXE) and Synchrotron X Ray Fluorescence (SXRF). When present at or near chondritic abundances the trace elements K, Ti, Cr, Mn, Cu, Zn, Ga, Ge, Se, and Br are presently detectable by SXRF in particles of 20 micron diameter. Improvements to the SXRF analysis facility at the National Synchrotron Light Source presently underway should increase the range of detectable elements and permit the analysis of smaller samples. In addition the Advanced Photon Source will be commissioned at Argonne National Laboratory in 1995. This 7 to 8 GeV positron storage ring, specifically designed for high-energy undulator and wiggler insertion devices, will be an ideal source for an x ray microprobe with one micron spatial resolution and better than 100 ppb elemental sensitivity for most elements. Thus trace element analysis of individual micron-sized grains should be possible by the time of the comet nucleus sample return mission.

Design principles of nuclear receptor signaling: how complex networking improves signal transduction

PubMed Central

Kolodkin, Alexey N; Bruggeman, Frank J; Plant, Nick; Moné, Martijn J; Bakker, Barbara M; Campbell, Moray J; van Leeuwen, Johannes P T M; Carlberg, Carsten; Snoep, Jacky L; Westerhoff, Hans V

2010-01-01

The topology of nuclear receptor (NR) signaling is captured in a systems biological graphical notation. This enables us to identify a number of ‘design' aspects of the topology of these networks that might appear unnecessarily complex or even functionally paradoxical. In realistic kinetic models of increasing complexity, calculations show how these features correspond to potentially important design principles, e.g.: (i) cytosolic ‘nuclear' receptor may shuttle signal molecules to the nucleus, (ii) the active export of NRs may ensure that there is sufficient receptor protein to capture ligand at the cytoplasmic membrane, (iii) a three conveyor belts design dissipating GTP-free energy, greatly aids response, (iv) the active export of importins may prevent sequestration of NRs by importins in the nucleus and (v) the unspecific nature of the nuclear pore may ensure signal-flux robustness. In addition, the models developed are suitable for implementation in specific cases of NR-mediated signaling, to predict individual receptor functions and differential sensitivity toward physiological and pharmacological ligands. PMID:21179018

Neutron production during the interaction of monoenergetic electrons with a Tungsten foil in the radiotherapeutic energy range

NASA Astrophysics Data System (ADS)

Soto-Bernal, Tzinnia Gabriela; Baltazar-Raigosa, Antonio; Medina-Castro, Diego; Vega-Carrillo, Hector Rene

2017-10-01

The electron, photon, and neutron spectra produced during the interaction between monoenergetic electron beams (8, 10, 12, 15, and 18 MeV) and a 0.05 cm-thick tungsten scattering foil were estimated using Monte Carlo method. Incoming electrons is a pencil beam that after collide with the foil acquires a broader distribution peaked in the same direction of the incoming electrons. Electron spectra show the influence of the binding energy of electrons in the tungsten shells and the increase of the electron fluence. In the interaction between the electrons in the beam and the tungsten atoms in the foil, bremsstrahlung and characteristic photons are produced. These photons are also peaked in the same direction of the incoming beam, and the electron fluence increases as the energy of the electron beam raises. The electron and photon spectra have particles whose energy is larger than the binding energy of neutron in the nucleus. Thus neutron production was noticed for 10, 12, 15, and 18 MeV electron beam. The neutron fluence becomes larger as the energy of the electron beam increases, the neutron spectra are mainly evaporation neutrons for 10 and 12 MeV, and for 15 and 18 MeV knock-on neutrons are also produced. Neutrons are produced in the foil volume having a quasi-isotropic distribution.

Review on DTU-parton model for hadron-hadron and hadron-nucleus collisions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chiu, C.B.

1980-08-01

The parton picture of color separation of dual string and its subsequent breakup is used to motivate the DTU-parton model for high energy small p/sub T/ multiparticle productions in hadron-hadron and hadron-nucleus collisions. A brief survey on phenomenological applications of the model: such as the inclusive spectra for various hh processes and central plateau heights predicted, hA inclusive spectra and the approximate anti v-universalities is presented.

Non-classical nuclei and growth kinetics of Cr precipitates in FeCr alloys during ageing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Yulan; Hu, Shenyang Y.; Zhang, Lei

2014-01-10

In this manuscript, we quantitatively calculated the thermodynamic properties of critical nuclei of Cr precipitates in FeCr alloys. The concentration profiles of the critical nuclei and nucleation energy barriers were predicted by the constrained shrinking dimer dynamics (CSDD) method. It is found that Cr concentration distribution in the critical nuclei strongly depend on the overall Cr concentration as well as temperature. The critical nuclei are non-classical because the concentration in the nuclei is smaller than the thermodynamic equilibrium value. These results are in agreement with atomic probe observation. The growth kinetics of both classical and non-classical nuclei was investigated bymore » the phase field approach. The simulations of critical nucleus evolution showed a number of interesting phenomena: 1) a critical classical nucleus first shrinks toward its non-classical nucleus and then grows; 2) a non-classical nucleus has much slower growth kinetics at its earlier growth stage compared to the diffusion-controlled growth kinetics. 3) a critical classical nucleus grows faster at the earlier growth stage than the non-classical nucleus. All of these results demonstrate that it is critical to introduce the correct critical nuclei in order to correctly capture the kinetics of precipitation.« less

Meson-nucleus potentials and the search for meson-nucleus bound states

NASA Astrophysics Data System (ADS)

Metag, V.; Nanova, M.; Paryev, E. Ya.

2017-11-01

Recent experiments studying the meson-nucleus interaction to extract meson-nucleus potentials are reviewed. The real part of the potentials quantifies whether the interaction is attractive or repulsive while the imaginary part describes the meson absorption in nuclei. The review is focused on mesons which are sufficiently long-lived to potentially form meson-nucleus quasi-bound states. The presentation is confined to meson production off nuclei in photon-, pion-, proton-, and light-ion induced reactions and heavy-ion collisions at energies near the production threshold. Tools to extract the potential parameters are presented. In most cases, the real part of the potential is determined by comparing measured meson momentum distributions or excitation functions with collision model or transport model calculations. The imaginary part is extracted from transparency ratio measurements. Results on K+ ,K0 ,K- , η ,η‧ , ω, and ϕ mesons are presented and compared with theoretical predictions. The interaction of K+ and K0 mesons with nuclei is found to be weakly repulsive, while the K- , η ,η‧ , ω and ϕ meson-nucleus potentials are attractive, however, with widely different strengths. Because of meson absorption in the nuclear medium the imaginary parts of the meson-nucleus potentials are all negative, again with a large spread. An outlook on planned experiments in the charm sector is given. In view of the determined potential parameters, the criteria and chances for experimentally observing meson-nucleus quasi-bound states are discussed. The most promising candidates appear to be the η and η‧ mesons.

Oral alprazolam acutely increases nucleus accumbens perfusion

PubMed Central

Wolf, Daniel H.; Pinkham, Amy E.; Satterthwaite, Theodore D.; Ruparel, Kosha; Elliott, Mark A.; Valdez, Jeffrey; Smith, Mark A.; Detre, John A.; Gur, Ruben C.; Gur, Raquel E.

2014-01-01

Benzodiazepines treat anxiety, but can also produce euphoric effects, contributing to abuse. Using perfusion magnetic resonance imaging, we provide the first direct evidence in humans that alprazolam (Xanax) acutely increases perfusion in the nucleus accumbens, a key reward-processing region linked to addiction. PMID:23070072

Shape coexistence in the N = 19 neutron-rich nucleus 31Mg explored by β-γ spectroscopy of spin-polarized 31Na

NASA Astrophysics Data System (ADS)

Nishibata, H.; Shimoda, T.; Odahara, A.; Morimoto, S.; Kanaya, S.; Yagi, A.; Kanaoka, H.; Pearson, M. R.; Levy, C. D. P.; Kimura, M.

2017-04-01

The structure of excited states in the neutron-rich nucleus 31Mg, which is in the region of the ;island of inversion; associated with the neutron magic number N = 20, is studied by β-γ spectroscopy of spin-polarized 31Na. Among the 31Mg levels below the one neutron separation energy of 2.3 MeV, the spin values of all five positive-parity levels are unambiguously determined by observing the anisotropic β decay. Two rotational bands with Kπ = 1 /2+ and 1 /2- are proposed based on the spins and energies of the levels. Comparison on a level-by-level basis is performed between the experimental results and theoretical calculations by the antisymmetrized molecular dynamics (AMD) plus generator coordinate method (GCM). It is found that various nuclear structures coexist in the low excitation energy region in 31Mg.

Coded-aperture imaging of the Galactic center region at gamma-ray energies

NASA Technical Reports Server (NTRS)

Cook, Walter R.; Grunsfeld, John M.; Heindl, William A.; Palmer, David M.; Prince, Thomas A.

1991-01-01

The first coded-aperture images of the Galactic center region at energies above 30 keV have revealed two strong gamma-ray sources. One source has been identified with the X-ray source IE 1740.7 - 2942, located 0.8 deg away from the nucleus. If this source is at the distance of the Galactic center, it is one of the most luminous objects in the galaxy at energies from 35 to 200 keV. The second source is consistent in location with the X-ray source GX 354 + 0 (MXB 1728-34). In addition, gamma-ray flux from the location of GX 1 + 4 was marginally detected at a level consistent with other post-1980 measurements. No significant hard X-ray or gamma-ray flux was detected from the direction of the Galactic nucleus or from the direction of the recently discovered gamma-ray source GRS 1758-258.

The tightly bound nuclei in the liquid drop model

NASA Astrophysics Data System (ADS)

Sree Harsha, N. R.

2018-05-01

In this paper, we shall maximise the binding energy per nucleon function in the semi-empirical mass formula of the liquid drop model of the atomic nuclei to analytically prove that the mean binding energy per nucleon curve has local extrema at A ≈ 58.6960, Z ≈ 26.3908 and at A ≈ 62.0178, Z ≈ 27.7506. The Lagrange method of multipliers is used to arrive at these results, while we have let the values of A and Z take continuous fractional values. The shell model that shows why 62Ni is the most tightly bound nucleus is outlined. A brief account on stellar nucleosynthesis is presented to show why 56Fe is more abundant than 62Ni and 58Fe. We believe that the analytical proof presented in this paper can be a useful tool to the instructors to introduce the nucleus with the highest mean binding energy per nucleon.

The threshold laws for electron-atom and positron-atom impact ionization

NASA Technical Reports Server (NTRS)

Temkin, A.

1983-01-01

The Coulomb-dipole theory is employed to derive a threshold law for the lowest energy needed for the separation of three particles from one another. The study focuses on an electron impinging on a neutral atom, and the dipole is formed between an inner electron and the nucleus. The analytical dependence of the transition matrix element on energy is reduced to lowest order to obtain the threshold law, with the inner electron providing a shield for the nucleus. Experimental results using the LAMPF accelerator to produce a high energy beam of H- ions, which are then exposed to an optical laser beam to detach the negative H- ion, are discussed. The threshold level is found to be confined to the region defined by the upper bound of the inverse square of the Coulomb-dipole region. Difficulties in exact experimental confirmation of the threshold are considered.

Flavor-dependent eigenvolume interactions in a hadron resonance gas

NASA Astrophysics Data System (ADS)

Alba, P.; Vovchenko, V.; Gorenstein, M. I.; Stoecker, H.

2018-06-01

Eigenvolume effects in the hadron resonance gas (HRG) model are studied for experimental hadronic yields in nucleus-nucleus collisions. If particle eigenvolumes are different for different hadron species, the excluded volume HRG (EV-HRG) improves fits to multiplicity data. In particular, using different mass-volume relations for strange and non-strange hadrons we observe a remarkable improvement in the quality of the fits. This effect appears to be rather insensitive to other details in the schemes employed in the EV-HRG. We show that the parameters found from fitting the data of the ALICE Collaboration in central Pb+Pb collisions at the collision energy √{sNN } = 2.76 TeV entail the same improvement for all centralities at the same collision energy, and for the RHIC and SPS data at lower collision energies. Our findings are put in the context of recent fits of lattice QCD results.

Homogenous Nucleation and Crystal Growth in a Model Liquid from Direct Energy Landscape Sampling Simulation

NASA Astrophysics Data System (ADS)

Walter, Nathan; Zhang, Yang

Nucleation and crystal growth are understood to be activated processes involving the crossing of free-energy barriers. Attempts to capture the entire crystallization process over long timescales with molecular dynamic simulations have met major obstacles because of molecular dynamics' temporal constraints. Herein, we circumvent this temporal limitation by using a brutal-force, metadynamics-like, adaptive basin-climbing algorithm and directly sample the free-energy landscape of a model liquid Argon. The algorithm biases the system to evolve from an amorphous liquid like structure towards an FCC crystal through inherent structure, and then traces back the energy barriers. Consequently, the sampled timescale is macroscopically long. We observe that the formation of a crystal involves two processes, each with a unique temperature-dependent energy barrier. One barrier corresponds to the crystal nucleus formation; the other barrier corresponds to the crystal growth. We find the two processes dominate in different temperature regimes. Compared to other computation techniques, our method requires no assumptions about the shape or chemical potential of the critical crystal nucleus. The success of this method is encouraging for studying the crystallization of more complex

The human subthalamic nucleus encodes the subjective value of reward and the cost of effort during decision-making

PubMed Central

Zénon, Alexandre; Duclos, Yann; Carron, Romain; Witjas, Tatiana; Baunez, Christelle; Régis, Jean; Azulay, Jean-Philippe; Brown, Peter; Eusebio, Alexandre

2016-01-01

Adaptive behaviour entails the capacity to select actions as a function of their energy cost and expected value and the disruption of this faculty is now viewed as a possible cause of the symptoms of Parkinson’s disease. Indirect evidence points to the involvement of the subthalamic nucleus—the most common target for deep brain stimulation in Parkinson’s disease—in cost-benefit computation. However, this putative function appears at odds with the current view that the subthalamic nucleus is important for adjusting behaviour to conflict. Here we tested these contrasting hypotheses by recording the neuronal activity of the subthalamic nucleus of patients with Parkinson’s disease during an effort-based decision task. Local field potentials were recorded from the subthalamic nucleus of 12 patients with advanced Parkinson’s disease (mean age 63.8 years ± 6.8; mean disease duration 9.4 years ± 2.5) both OFF and ON levodopa while they had to decide whether to engage in an effort task based on the level of effort required and the value of the reward promised in return. The data were analysed using generalized linear mixed models and cluster-based permutation methods. Behaviourally, the probability of trial acceptance increased with the reward value and decreased with the required effort level. Dopamine replacement therapy increased the rate of acceptance for efforts associated with low rewards. When recording the subthalamic nucleus activity, we found a clear neural response to both reward and effort cues in the 1–10 Hz range. In addition these responses were informative of the subjective value of reward and level of effort rather than their actual quantities, such that they were predictive of the participant’s decisions. OFF levodopa, this link with acceptance was weakened. Finally, we found that these responses did not index conflict, as they did not vary as a function of the distance from indifference in the acceptance decision. These findings show that low-frequency neuronal activity in the subthalamic nucleus may encode the information required to make cost-benefit comparisons, rather than signal conflict. The link between these neural responses and behaviour was stronger under dopamine replacement therapy. Our findings are consistent with the view that Parkinson’s disease symptoms may be caused by a disruption of the processes involved in balancing the value of actions with their associated effort cost. PMID:27190012

Nanosecond lifetime measurements of Iπ=9/2- intrinsic excited states and low-lying B(E1) strengths in 183Re using combined HPGe-LaBr3 coincidence spectroscopy

NASA Astrophysics Data System (ADS)

Gurgi, L. A.; Regan, P. H.; Daniel, T.; Podolyák, Zs.; Bruce, A. M.; Mason, P. J. R.; Mǎrginean, N.; Mǎrginean, R.; Werner, V.; Alharbi, T.; Alkhomashi, N.; Bajoga, A. D.; Britton, R.; Cǎta-Danil, I.; Carroll, R. J.; Deleanu, D.; Bucurescu, D.; Florea, N.; Gheorghe, I.; Ghita, D. G.; Glodariu, T.; Lice, R.; Mihai, C.; Mulholland, K. F.; Negret, A.; Olacel, A.; Roberts, O. J.; Sava, T.; Söderström, P.-A.; Stroe, L.; Suvaila, R.; Toma, S.; Wilson, E.; Wood, R. T.

2017-08-01

This paper presents precision measurements of electromagnetic decay probabilities associated with electric dipole transitions in the prolate-deformed nucleus 183Re. The nucleus of interest was formed using the fusion evaporation reaction 180Hf(7Li,4n)183Re at a beam energy of 30 MeV at the tandem accelerator at the HH-IFIN Institute, Bucharest Romania. Coincident decay gamma rays from near-yrast cascades were detected using the combined HPGe-LaBr3 detector array ROSPHERE. The time differences between cascade gamma rays were measured using the LaBr3 detectors to determine the half-lives of the two lowest lying spin-parity 9/2- states at excitation energies of 496 and 617 keV to be 5.65(5) and 2.08(3) ns respectively. The deduced E1 transition rates from these two states are discussed in terms of the K-hindrance between the low-lying structures in this prolate-deformed nucleus.

Vacuum low-temperature superconductivity is the essence of superconductivity - Atomic New Theory

NASA Astrophysics Data System (ADS)

Yongquan, Han

2010-10-01

The universe when the temperature closest to the Big Bang the temperature should be nuclear. Because, after the big bang, instant formation of atoms, nuclei and electrons between the absolute vacuum, the nucleus can not emit energy. (Radioactive elements, except in fact, radiation Yuan Su limited power emitted) which causes atomic nuclei and external temperature difference are so enormous that a large temperature difference reasons, all external particles became closer to the nucleus, affect the motion of electrons. When the conductor conductivity and thus affect the conductivity, the formation of resistance. Assumption that no particles affect the motion of electrons (except outside the nucleus) to form a potential difference will not change after the vector form, is now talking about the phenomenon of superconductivity, and then to introduce general, the gap between atoms in molecules or between small, valence electron number of high temperature superconducting conductors. This theory of atomic nuclei, but also explain the atomic and hydrogen bombs can remain after an explosion Why can release enormous energy reasons. Can also explain the ``super flow'' phenomenon. natural world. Tel 13241375685

Branching ratios of α-decay to ground and excited states of Fm, Cf, Cm and Pu

NASA Astrophysics Data System (ADS)

Hassanabadi, H.; Hosseini, S. S.

2018-06-01

We use the well-known Wentzel-Kramers-Brillouin (WKB) barrier penetration probability to calculate α-decay branching ratios for ground and excited states of heavy even-even nuclei of Fermium (248-254Fm), Californium (244-252Cf), Curium (238-248Cm) and Plutonium (234-244Pu) with 94 ≤Zp ≤100. We obtained the branching ratios for the excited states of daughter nucleus by the α-decay energy (Qα), the angular momentum of α-particle (ℓα), and the excitation probability of the daughter nucleus with the excitation energy of state ℓ in the daughter nucleus (i.e. Eℓ*). α-Decay half-lives have been evaluated by using the proximity potential model for the heavy even-even nuclei. We have reported the half-lives and compared the results with the experimental data. The theoretical branching ratios of α-transitions in our calculation are found to agree with the available experimental data well for 0+→ 0+, 0+→ 2+, 0+→ 4+, 0+→ 6+ and 0+ → 8+α-transitions.

Melanin-Concentrating Hormone: A New Sleep Factor?

PubMed Central

Torterolo, Pablo; Lagos, Patricia; Monti, Jaime M.

2011-01-01

Neurons containing the neuropeptide melanin-concentrating hormone (MCH) are mainly located in the lateral hypothalamus and the incerto-hypothalamic area, and have widespread projections throughout the brain. While the biological functions of this neuropeptide are exerted in humans through two metabotropic receptors, the MCHR1 and MCHR2, only the MCHR1 is present in rodents. Recently, it has been shown that the MCHergic system is involved in the control of sleep. We can summarize the experimental findings as follows: (1) The areas related to the control of sleep and wakefulness have a high density of MCHergic fibers and receptors. (2) MCHergic neurons are active during sleep, especially during rapid eye movement (REM) sleep. (3) MCH knockout mice have less REM sleep, notably under conditions of negative energy balance. Animals with genetically inactivated MCHR1 also exhibit altered vigilance state architecture and sleep homeostasis. (4) Systemically administered MCHR1 antagonists reduce sleep. (5) Intraventricular microinjection of MCH increases both slow wave sleep (SWS) and REM sleep; however, the increment in REM sleep is more pronounced. (6) Microinjection of MCH into the dorsal raphe nucleus increases REM sleep time. REM seep is inhibited by immunoneutralization of MCH within this nucleus. (7) Microinjection of MCH in the nucleus pontis oralis of the cat enhances REM sleep time and reduces REM sleep latency. All these data strongly suggest that MCH has a potent role in the promotion of sleep. Although both SWS and REM sleep are facilitated by MCH, REM sleep seems to be more sensitive to MCH modulation. PMID:21516258

Neuronal hypothalamic regulation of body metabolism and bone density is galanin dependent.

PubMed

Idelevich, Anna; Sato, Kazusa; Nagano, Kenichi; Rowe, Glenn; Gori, Francesca; Baron, Roland

2018-06-01

In the brain, the ventral hypothalamus (VHT) regulates energy and bone metabolism. Whether this regulation uses the same or different neuronal circuits is unknown. Alteration of AP1 signaling in the VHT increases energy expenditure, glucose utilization, and bone density, yet the specific neurons responsible for each or all of these phenotypes are not identified. Using neuron-specific, genetically targeted AP1 alterations as a tool in adult mice, we found that agouti-related peptide-expressing (AgRP-expressing) or proopiomelanocortin-expressing (POMC-expressing) neurons, predominantly present in the arcuate nucleus (ARC) within the VHT, stimulate whole-body energy expenditure, glucose utilization, and bone formation and density, although their effects on bone resorption differed. In contrast, AP1 alterations in steroidogenic factor 1-expressing (SF1-expressing) neurons, present in the ventromedial hypothalamus (VMH), increase energy but decrease bone density, suggesting that these effects are independent. Altered AP1 signaling also increased the level of the neuromediator galanin in the hypothalamus. Global galanin deletion (VHT galanin silencing using shRNA) or pharmacological galanin receptor blockade counteracted the observed effects on energy and bone. Thus, AP1 antagonism reveals that AgRP- and POMC-expressing neurons can stimulate body metabolism and increase bone density, with galanin acting as a central downstream effector. The results obtained with SF1-expressing neurons, however, indicate that bone homeostasis is not always dictated by the global energy status, and vice versa.

Palmitic acid mediates hypothalamic insulin resistance by altering PKC-theta subcellular localization in rodents.

PubMed

Benoit, Stephen C; Kemp, Christopher J; Elias, Carol F; Abplanalp, William; Herman, James P; Migrenne, Stephanie; Lefevre, Anne-Laure; Cruciani-Guglielmacci, Céline; Magnan, Christophe; Yu, Fang; Niswender, Kevin; Irani, Boman G; Holland, William L; Clegg, Deborah J

2009-09-01

Insulin signaling can be modulated by several isoforms of PKC in peripheral tissues. Here, we assessed whether one specific isoform, PKC-theta, was expressed in critical CNS regions that regulate energy balance and whether it mediated the deleterious effects of diets high in fat, specifically palmitic acid, on hypothalamic insulin activity in rats and mice. Using a combination of in situ hybridization and immunohistochemistry, we found that PKC-theta was expressed in discrete neuronal populations of the arcuate nucleus, specifically the neuropeptide Y/agouti-related protein neurons and the dorsal medial nucleus in the hypothalamus. CNS exposure to palmitic acid via direct infusion or by oral gavage increased the localization of PKC-theta to cell membranes in the hypothalamus, which was associated with impaired hypothalamic insulin and leptin signaling. This finding was specific for palmitic acid, as the monounsaturated fatty acid, oleic acid, neither increased membrane localization of PKC-theta nor induced insulin resistance. Finally, arcuate-specific knockdown of PKC-theta attenuated diet-induced obesity and improved insulin signaling. These results suggest that many of the deleterious effects of high-fat diets, specifically those enriched with palmitic acid, are CNS mediated via PKC-theta activation, resulting in reduced insulin activity.

Optimization of Light-Harvesting Pigment Improves Photosynthetic Efficiency.

PubMed

Jin, Honglei; Li, Mengshu; Duan, Sujuan; Fu, Mei; Dong, Xiaoxiao; Liu, Bing; Feng, Dongru; Wang, Jinfa; Wang, Hong-Bin

2016-11-01

Maximizing light capture by light-harvesting pigment optimization represents an attractive but challenging strategy to improve photosynthetic efficiency. Here, we report that loss of a previously uncharacterized gene, HIGH PHOTOSYNTHETIC EFFICIENCY1 (HPE1), optimizes light-harvesting pigments, leading to improved photosynthetic efficiency and biomass production. Arabidopsis (Arabidopsis thaliana) hpe1 mutants show faster electron transport and increased contents of carbohydrates. HPE1 encodes a chloroplast protein containing an RNA recognition motif that directly associates with and regulates the splicing of target RNAs of plastid genes. HPE1 also interacts with other plastid RNA-splicing factors, including CAF1 and OTP51, which share common targets with HPE1. Deficiency of HPE1 alters the expression of nucleus-encoded chlorophyll-related genes, probably through plastid-to-nucleus signaling, causing decreased total content of chlorophyll (a+b) in a limited range but increased chlorophyll a/b ratio. Interestingly, this adjustment of light-harvesting pigment reduces antenna size, improves light capture, decreases energy loss, mitigates photodamage, and enhances photosynthetic quantum yield during photosynthesis. Our findings suggest a novel strategy to optimize light-harvesting pigments that improves photosynthetic efficiency and biomass production in higher plants. © 2016 American Society of Plant Biologists. All Rights Reserved.

Optimization of Light-Harvesting Pigment Improves Photosynthetic Efficiency1[OPEN

PubMed Central

Jin, Honglei; Li, Mengshu; Duan, Sujuan; Fu, Mei; Dong, Xiaoxiao; Feng, Dongru; Wang, Jinfa

2016-01-01

Maximizing light capture by light-harvesting pigment optimization represents an attractive but challenging strategy to improve photosynthetic efficiency. Here, we report that loss of a previously uncharacterized gene, HIGH PHOTOSYNTHETIC EFFICIENCY1 (HPE1), optimizes light-harvesting pigments, leading to improved photosynthetic efficiency and biomass production. Arabidopsis (Arabidopsis thaliana) hpe1 mutants show faster electron transport and increased contents of carbohydrates. HPE1 encodes a chloroplast protein containing an RNA recognition motif that directly associates with and regulates the splicing of target RNAs of plastid genes. HPE1 also interacts with other plastid RNA-splicing factors, including CAF1 and OTP51, which share common targets with HPE1. Deficiency of HPE1 alters the expression of nucleus-encoded chlorophyll-related genes, probably through plastid-to-nucleus signaling, causing decreased total content of chlorophyll (a+b) in a limited range but increased chlorophyll a/b ratio. Interestingly, this adjustment of light-harvesting pigment reduces antenna size, improves light capture, decreases energy loss, mitigates photodamage, and enhances photosynthetic quantum yield during photosynthesis. Our findings suggest a novel strategy to optimize light-harvesting pigments that improves photosynthetic efficiency and biomass production in higher plants. PMID:27609860

Size distribution and growth rate of crystal nuclei near critical undercooling in small volumes

NASA Astrophysics Data System (ADS)

Kožíšek, Z.; Demo, P.

2017-11-01

Kinetic equations are numerically solved within standard nucleation model to determine the size distribution of nuclei in small volumes near critical undercooling. Critical undercooling, when first nuclei are detected within the system, depends on the droplet volume. The size distribution of nuclei reaches the stationary value after some time delay and decreases with nucleus size. Only a certain maximum size of nuclei is reached in small volumes near critical undercooling. As a model system, we selected recently studied nucleation in Ni droplet [J. Bokeloh et al., Phys. Rev. Let. 107 (2011) 145701] due to available experimental and simulation data. However, using these data for sample masses from 23 μg up to 63 mg (corresponding to experiments) leads to the size distribution of nuclei, when no critical nuclei in Ni droplet are formed (the number of critical nuclei < 1). If one takes into account the size dependence of the interfacial energy, the size distribution of nuclei increases to reasonable values. In lower volumes (V ≤ 10-9 m3) nucleus size reaches some maximum extreme size, which quickly increases with undercooling. Supercritical clusters continue their growth only if the number of critical nuclei is sufficiently high.

Gallic acid inhibits the release of ADAMTS4 in nucleus pulposus cells by inhibiting p65 phosphorylation and acetylation of the NF-κB signaling pathway.

PubMed

Huang, Yao; Chen, Jian; Jiang, Tao; Zhou, Zheng; Lv, Bin; Yin, Guoyong; Fan, Jin

2017-07-18

This study investigated the inhibitory effect of gallic acid (GA) on the release of A Disintegrin and Metalloproteinase with Thrombospondin motifs 4 (ADAMTS4) through the regulation of the NF-κB signaling pathway, which is closely related to the matrix metalloproteinases in nucleus pulposus cells. Different concentrations of GA were added to TNF-α-induced human nucleus pulposus cells (hNPCs) and intervertebral disc degeneration rat model. ADAMTS-4 expression increased both in the TNF-α-induced nucleus pulposus cells and intervertebral disc degeneration rat model. By contrast, the release of ADAMTS-4 was reduced, and the TNF-α-induced apoptosis of nucleus pulposus cells was significantly inhibited after addition of GA at different concentrations. Further study found that the levels of phosphorylated p65 (p-p65) was increased and the classical NF-κB signal pathway was activated after the nucleus pulposus cells were stimulated by TNF-α. Meanwhile, GA suppressed the p65 phosphorylation and inceased p65 deacetylation levels. As a consequence, GA can decrease the expression of ADAMTS-4 in nucleus pulposus cells by regulating the phosphorylation and acetylation of p65 in NF-κB signaling pathways.

[Calcium distribution in the central cell of lettuce (Lactuca sativa L.) before and after pollination].

PubMed

Qiu, Yi Lan; Liu, Ru Shi; Ye, Lv; Tian, Hui

2008-02-01

Potassium antimonite precipitation was used to locate calcium in the central cell of lettuce (Lactuca sativa L.) before and after pollination. At 3d before anthesis, two polar nuclei of central cell separately located at two polarity of the cell, and few calcium precipitates (ppts) appeared in the polar nuclei and cytoplasm, but some ppts in its small vacuoles. At 2d before anthesis, two polar nuclei moved toward the middle of the cell and fused to form a secondary nucleus, and the ppts evidently increased in the nucleus and cytoplasm. At 1d before anthesis, secondary nucleus again moved toward micropylar end and located near the egg to prepare for fertilization. Calcium precipitates were mainly accumulated in the secondary nucleus. After pollination and before fertilization, the distribution of calcium ppts was similar to that before pollination. At 4h after pollination, the central cell was fertilized, and calcium ppts evidently increased in the cell and numerous were accumulated in its nucleus and cytoplasm. At 6h after pollination, the primary endosperm nucleus completed its first division and formed two dissociate endosperm nuclei, and still many calcium precipitates appeared in the nucleus and cytoplasm. With endosperm development, calcium ppts decreased in the endosperm cell. At 1d after emasculated and without pollination, the secondary nucleus of the cell still bordered on the egg and some calcium ppts appeared in the secondary nucleus. The results indicated that the temporal and spatial changes of calcium in the central cell may play an important physiological role during the development of the central cell and endosperm.

Testosterone Rapidly Augments Retrograde Endocannabinoid Signaling in Proopiomelanocortin Neurons to Suppress Glutamatergic Input from Steroidogenic Factor 1 Neurons via Upregulation of Diacylglycerol Lipase-α

PubMed Central

Conde, Kristie; Fabelo, Carolina; Krause, William C.; Propst, Robert; Goethel, Jordan; Fischer, Daniel; Hur, Jin; Meza, Cecilia; Ingraham, Holly A.; Wagner, Edward J.

2018-01-01

Testosterone exerts profound effects on reproduction and energy homeostasis. Like other orexigenic hormones, it increases endocannabinoid tone within the hypothalamic feeding circuitry. Therefore, we tested the hypothesis that testosterone upregulates the expression of diacylglycerol lipase (DAGL)α in the hypothalamic arcuate nucleus (ARC) to increase energy intake via enhanced endocannabinoid-mediated retrograde inhibition of anorexigenic proopiomelanocortin (POMC) neurons. Energy intake, meal patterns, and energy expenditure were evaluated in orchidectomized, male guinea pigs treated subcutaneously with testosterone propionate (TP; 400 μg) or its sesame oil vehicle (0.1 mL). TP rapidly increased energy intake, meal size, O2 consumption, CO2 production, and metabolic heat production, all of which were antagonized by prior administration of the DAGL inhibitor orlistat (3 μg) into the third ventricle. These orlistat-sensitive, TP-induced increases in energy intake and expenditure were temporally associated with a significant elevation in ARC DAGLα expression. Electrophysiological recordings in hypothalamic slices revealed that TP potentiated depolarization-induced suppression of excitatory glutamatergic input onto identified ARC POMC neurons, which was also abolished by orlistat (3 μM), the CB1 receptor antagonist AM251 (1 μM), and the AMP-activated protein kinase inhibitor compound C (30 μM) and simulated by transient bath application of the dihydrotestosterone mimetic Cl-4AS-1 (100 nM) and testosterone-conjugated bovine serum albumin (100 nM). Thus, testosterone boosts DAGLα expression to augment retrograde, presynaptic inhibition of glutamate release onto ARC POMC neurons that, in turn, increases energy intake and expenditure. These studies advance our understanding of how androgens work within the hypothalamic feeding circuitry to affect changes in energy balance. PMID:27871072

Fission Fragment Mass Distributions and Total Kinetic Energy Release of 235-Uranium and 238-Uranium in Neutron-Induced Fission at Intermediate and Fast Neutron Energies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Duke, Dana Lynn

2015-11-12

This Ph.D. dissertation describes a measurement of the change in mass distributions and average total kinetic energy (TKE) release with increasing incident neutron energy for fission of 235U and 238U. Although fission was discovered over seventy-five years ago, open questions remain about the physics of the fission process. The energy of the incident neutron, En, changes the division of energy release in the resulting fission fragments, however, the details of energy partitioning remain ambiguous because the nucleus is a many-body quantum system. Creating a full theoretical model is difficult and experimental data to validate existing models are lacking. Additional fissionmore » measurements will lead to higher-quality models of the fission process, therefore improving applications such as the development of next-generation nuclear reactors and defense. This work also paves the way for precision experiments such as the Time Projection Chamber (TPC) for fission cross section measurements and the Spectrometer for Ion Determination in Fission (SPIDER) for precision mass yields.« less

Total absorption γ -ray spectroscopy of the β -delayed neutron emitters Br 87 , Br 88 , and Rb 94

DOE PAGES

Valencia, E.; Tain, J. L.; Algora, A.; ...

2017-02-21

In this paper, we investigate the decay of 87,88Br and 94Rb using total absorption γ-ray spectroscopy. These important fission products are β-delayed neutron emitters. Our data show considerable βγ intensity, so far unobserved in high-resolution γ-ray spectroscopy, from states at high excitation energy. We also find significant differences with the β intensity that can be deduced from existing measurements of the β spectrum. We evaluate the impact of the present data on reactor decay heat using summation calculations. Although the effect is relatively small it helps to reduce the discrepancy between calculations and integral measurements of the photon component formore » 235U fission at cooling times in the range 1-100 s. We also use summation calculations to evaluate the impact of present data on reactor antineutrino spectra. We find a significant effect at antineutrino energies in the range of 5 to 9 MeV. In addition, we observe an unexpected strong probability for γ emission from neutron unbound states populated in the daughter nucleus. The γ branching is compared to Hauser-Feshbach calculations, which allow one to explain the large value for bromine isotopes as due to nuclear structure. However the branching for 94Rb, although much smaller, hints of the need to increase the radiative width Γ γ by one order of magnitude. Finally, this increase in Γ γ would lead to a similar increase in the calculated (n, γ) cross section for this very neutron-rich nucleus with a potential impact on r process abundance calculations.« less

Glenn T. Seaborg and heavy ion nuclear science

DOE Office of Scientific and Technical Information (OSTI.GOV)

Loveland, W.

1992-04-01

Radiochemistry has played a limited but important role in the study of nucleus-nucleus collisions. Many of the important radiochemical studies have taken place in Seaborg's laboratory or in the laboratories of others who have spent time in Berkeley working with Glenn T. Seaborg. I will discuss studies of low energy deep inelastic reactions with special emphasis on charge equilibration, studies of the properties of heavy residues in intermediate energy nuclear collisions and studies of target fragmentation in relativistic and ultrarelativistic reactions. The emphasis will be on the unique information afforded by radiochemistry and the physical insight derived from radiochemical studies.more » Future roles of radiochemistry in heavy ion nuclear science also will be discussed.« less

Glenn T. Seaborg and heavy ion nuclear science

DOE Office of Scientific and Technical Information (OSTI.GOV)

Loveland, W.

1992-04-01

Radiochemistry has played a limited but important role in the study of nucleus-nucleus collisions. Many of the important radiochemical studies have taken place in Seaborg`s laboratory or in the laboratories of others who have spent time in Berkeley working with Glenn T. Seaborg. I will discuss studies of low energy deep inelastic reactions with special emphasis on charge equilibration, studies of the properties of heavy residues in intermediate energy nuclear collisions and studies of target fragmentation in relativistic and ultrarelativistic reactions. The emphasis will be on the unique information afforded by radiochemistry and the physical insight derived from radiochemical studies.more » Future roles of radiochemistry in heavy ion nuclear science also will be discussed.« less

Competing decay modes of a high-spin isomer in the proton-unbound nucleus ¹⁵⁸Ta*

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carroll, R. J.; Page, R. D.; Joss, D. T.

2015-01-01

An isomeric state at high spin and excitation energy was recently observed in the proton-unbound nucleus 158Ta. This state was observed to decay by both α and γ decay modes. The large spin change required to decay via γ-ray emission incurs a lifetime long enough for α decay to compete. The α decay has an energy of 8644(11) keV, which is among the highest observed in the region, a partial half-life of 440(70) μs and changes the spin by 11ℏ. In this study, additional evidence supporting the assignment of this α decay to the high-spin isomer in 158Ta will bemore » presented.« less

Electron capture rates in stars studied with heavy ion charge exchange reactions

NASA Astrophysics Data System (ADS)

Bertulani, C. A.

2018-01-01

Indirect methods using nucleus-nucleus reactions at high energies (here, high energies mean ~ 50 MeV/nucleon and higher) are now routinely used to extract information of interest for nuclear astrophysics. This is of extreme relevance as many of the nuclei involved in stellar evolution are short-lived. Therefore, indirect methods became the focus of recent studies carried out in major nuclear physics facilities. Among such methods, heavy ion charge exchange is thought to be a useful tool to infer Gamow-Teller matrix elements needed to describe electron capture rates in stars and also double beta-decay experiments. In this short review, I provide a theoretical guidance based on a simple reaction model for charge exchange reactions.

Measurements of Reaction Cross Sections for 9-11C

NASA Astrophysics Data System (ADS)

Nishizuka, Kenji; Takechi, Maya; Ohtsubo, Takashi; Nishimura, Daiki; Fukuda, Mitsunori; Aoki, Kazuya; Abe, Keijiro; Ikeda, Ayaka; Izumikawa, Takuji; Oikawa, Hiroyuki; Ohnishi, Kosuke; Ohno, Junichi; Ohmika, Shunichiro; Kato, Ikuma; Kanke, Yuki; Kanbe, Shunsuke; Kanda, Naoto; Kikuchi, Haruka; Kitagawa, Atsushi; Sato, Shinji; Sayama, Umito; Shimaya, Jiro; Sugihara, Takanobu; Suzuki, Shinji; Suzuki, Takeshi; Takahashi, Hiroki; Taguchi, Yoshisada; Takei, Yuki; Takeuchi, Yuki; Takenouchi, Arashi; Takemoto, Takanori; Tadano, Natsuki; Tanaka, Masaomi; Tanaka, Yutaro; Chikaato, Kazuya; Du, Hang; Nagai, Takumi; Nagumo, Junya; Fukuda, Shigekazu; Hori, Kensyu; Honma, Akira; Machida, Masahiro; Matsunaga, Satoshi; Mizukami, Atsushi; Mihara, Mototsugu; Miyata, Eri; Murooka, Daiki; Yagi, Shoichi; Yamaoka, Shintaro; Yamaguchi, Takayuki; Yokoyama, Kouhei

In order to probe the differences of matter and charge radii of atomic nucleus in the proton-rich C isotopes, measurements of reaction cross sections (σR) for 9-11C on proton targets in the energy range from 50 to 120A MeV were performed at HIMAC facility, NIRS. Owing to the large differences between proton-proton and proton-neutron scattering cross sections at this intermediate energy region, σR data for atomic nuclei on proton targets are expected to have the sensitivity to the differences between proton and neutron distributions in the nucleus. Present preliminary data are compared with the Glauber calculation, which suggest the larger enhancements of proton distributions in 9C and 10C compared to 11C.

Improving cell penetration of helical peptides stabilized by N-terminal crosslinked aspartic acids.

PubMed

Zhao, Hui; Jiang, Yanhong; Tian, Yuan; Yang, Dan; Qin, Xuan; Li, Zigang

2017-01-04

Cell penetration and nucleus translocation efficiency are important for the cellular activities of peptide therapeutics. For helical peptides stabilized by N-terminal crosslinked aspartic acid, correlations between their penetration efficiency/nucleus translocation and physicochemical properties were studied. An increase in hydrophobicity and isoelectric point will promote cellular uptake and nucleus translocation of stabilized helices.

Behavioral Flexibility Is Increased by Optogenetic Inhibition of Neurons in the Nucleus Accumbens Shell during Specific Time Segments

ERIC Educational Resources Information Center

Aquili, Luca; Liu, Andrew W.; Shindou, Mayumi; Shindou, Tomomi; Wickens, Jeffery R.

2014-01-01

Behavioral flexibility is vital for survival in an environment of changing contingencies. The nucleus accumbens may play an important role in behavioral flexibility, representing learned stimulus-reward associations in neural activity during response selection and learning from results. To investigate the role of nucleus accumbens neural activity…

Momentum dependence of the imaginary part of the ω- and η^'-nucleus optical potential

NASA Astrophysics Data System (ADS)

Friedrich, S.; Nanova, M.; Metag, V.; Afzal, F. N.; Bayadilov, D.; Bantes, B.; Beck, R.; Becker, M.; Böse, S.; Brinkmann, K.-T.; Crede, V.; Drexler, P.; Eberhardt, H.; Elsner, D.; Frommberger, F.; Funke, Ch.; Gottschall, M.; Grüner, M.; Gutz, E.; Hammann, Ch.; Hannappel, J.; Hartmann, J.; Hillert, W.; Hoffmeister, Ph.; Honisch, Ch.; Jude, T.; Kaiser, D.; Kalischewski, F.; Keshelashvili, I.; Klein, F.; Koop, K.; Krusche, B.; Lang, M.; Makonyi, K.; Messi, F.; Müller, J.; Müllers, J.; Piontek, D.-M.; Rostomyan, T.; Schaab, D.; Schmidt, Ch.; Schmieden, H.; Schmitz, R.; Seifen, T.; Sokhoyan, V.; Sowa, C.; Spieker, K.; Thiel, A.; Thoma, U.; Triffterer, T.; Urban, M.; van Pee, H.; Walther, D.; Wendel, Ch.; Werthmüller, D.; Wiedner, U.; Wilson, A.; Witthauer, L.; Wunderlich, Y.; Zaunick, H.-G.

2016-09-01

The photoproduction of ω and η^' mesons off carbon and niobium nuclei has been measured as a function of the meson momentum for incident photon energies of 1.2-2.9GeV at the electron accelerator ELSA. The mesons have been identified via the ω → π0 γ → 3 γ and η^' → π0 π0η → 6 γ decays, respectively, registered with the CBELSA/TAPS detector system. From the measured meson momentum distributions the momentum dependence of the transparency ratio has been determined for both mesons. Within a Glauber analysis the in-medium ω and η^' widths and the corresponding absorption cross sections have been deduced as a function of the meson momentum. The results are compared to recent theoretical predictions for the in-medium ω width and η^'-N absorption cross sections. The energy dependence of the imaginary part of the ω- and η^'-nucleus optical potential has been extracted. The finer binning of the present data compared to the existing data allows a more reliable extrapolation towards the production threshold. The modulus of the imaginary part of the η^'-nucleus potential is found to be about three times smaller than recently determined values of the real part of the η^'-nucleus potential, which makes the η^' meson a suitable candidate for the search for meson-nucleus bound states. For the ω meson, the modulus of the imaginary part near threshold is comparable to the modulus of the real part of the potential. As a consequence, only broad structures can be expected, which makes the observation of ω mesic states very difficult experimentally.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alvioli, M.; Frankfurt, L.; Guzey, V.

Here, we model effects of color fluctuations (CFs) in the light-cone photon wave function and for the first time make predictions for the distribution over the number of wounded nucleons ν in the inelastic photon–nucleus scattering. We show that CFs lead to a dramatic enhancement of this distribution at ν=1 and large ν>10. We also study the implications of different scales and CFs in the photon wave function on the total transverse energy ΣE T and other observables in inelastic γA scattering with different triggers. Our predictions can be tested in proton–nucleus and nucleus–nucleus ultraperipheral collisions at the LHC andmore » will help to map CFs, whose first indications have already been observed at the LHC.« less

Tracing the origin of azimuthal gluon correlations in the color glass condensate

NASA Astrophysics Data System (ADS)

Lappi, T.; Schenke, B.; Schlichting, S.; Venugopalan, R.

2016-01-01

We examine the origins of azimuthal correlations observed in high energy proton-nucleus collisions by considering the simple example of the scattering of uncorrelated partons off color fields in a large nucleus. We demonstrate how the physics of fluctuating color fields in the color glass condensate (CGC) effective theory generates these azimuthal multiparticle correlations and compute the corresponding Fourier coefficients v n within different CGC approximation schemes. We discuss in detail the qualitative and quantitative differences between the different schemes. We will show how a recently introduced color field domain model that captures key features of the observed azimuthal correlations can be understood in the CGC effective theory as a model of non-Gaussian correlations in the target nucleus.

Accumulation of glycogen in axotomized adult rat facial motoneurons.

PubMed

Takezawa, Yosuke; Baba, Otto; Kohsaka, Shinichi; Nakajima, Kazuyuki

2015-06-01

This study biochemically determined glycogen content in the axotomized facial nucleus of adult rats up to 35 days postinsult. The amounts of glycogen in the transected facial nucleus were significantly increased at 5 days postinsult, peaked at 7 days postinsult, and declined to the control levels at 21-35 days postinsult. Immunohistochemical analysis with antiglycogen antibody revealed that the quantity of glycogen granules in the axotomized facial nucleus was greater than that in the control nucleus at 7 days postinjury. Dual staining methods with antiglycogen antibody and a motoneuron marker clarified that the glycogen was localized mainly in motoneurons. Immunoblotting and quantification analysis revealed that the ratio of inactive glycogen synthase (GS) to total GS was significantly decreased in the injured nucleus at about 1-3 days postinsult and significantly increased from 7 to 14 days postinsult, suggesting that glycogen is actively synthesized in the early period postinjury but suppressed after 7 days postinsult. The enhanced glycogen at about 5-7 days postinsult is suggested to be responsible for the decrease in inactive GS levels, and the decrease of glycogen after 7 days postinsult is considered to be caused by increased inactive GS levels and possibly the increase in active glycogen phosphorylase. © 2015 Wiley Periodicals, Inc.

JPRS Report, Science and Technology, Europe.

DTIC Science & Technology

1989-06-16

nature of their central energy sources, to the complex distribution of gases around the nucleus and possibly to understanding the origin of the diffuse...development. CCD’s are ideal for single photon X-ray imaging and spectroscopy. They have a high quantum efficiency over a broad energy range, high spatial...resolution, low readout noise, and an energy resolution approaching 100 at high energy levels. Reflection gratings have been chosen for XMM rather

Nuclear reactions induced by high-energy alpha particles

NASA Technical Reports Server (NTRS)

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.

Agouti-related protein increases food hoarding more than food intake in Siberian hamsters.

PubMed

Day, Diane E; Bartness, Timothy J

2004-01-01

Agouti-related protein (AgRP), an endogenous melanocortin 3/4 receptor antagonist, appears to play an important role in the control of food intake and energy balance because exogenous administration in rats and overexpression in mice result in hyperphagia and body mass gain. Furthermore, arcuate nucleus AgRP mRNA is increased with fasting in laboratory rats and mice and is decreased with refeeding. In Siberian hamsters, fasting also increases arcuate nucleus AgRP mRNA, but these animals increase food hoarding, rather than food intake with refeeding. Therefore, we tested whether exogenous AgRP increased food hoarding in this species. Hamsters were trained in a hoarding/foraging apparatus to run a programmed number of wheel revolutions to earn food pellets. Four doses of AgRP-(83-132) or vehicle were injected into the third ventricle at the beginning of the dark phase, and food hoarding, food intake, and foraging were measured at various time points subsequently. Overall, food hoarding was stimulated as much as 10 times more than food intake, and both responses occurred as early as 1 h after injection. Food hoarding was increased the greatest at the lowest dose (0.1 nmol), whereas food intake was increased the greatest at the second lowest dose (1 nmol). Food intake and especially food hoarding were increased up to seven days after the AgRP injections. Foraging was increased at all AgRP doses except the highest dose (100 nmol). These results suggest that AgRP triggers the search for food in this species, and once they find it, hoarding predominates over eating.

Sensitivity of the nuclear deformability and fission barriers to the equation of state

NASA Astrophysics Data System (ADS)

Seif, W. M.; Anwer, Hisham

2018-07-01

The model-dependent analysis of the fission data impacts the extracted fission-related quantities, which are not directly observables, such as the super- and hyperdeformed isomeric states and their energies. We investigated the model dependence of the deformability of a nucleus and its fission barriers on the nuclear equation of state. Within the microscopic-macroscopic model based on a large number of Skyrme nucleon-nucleon interactions, the total energy surfaces and the double-humped fission barrier of 230Th are calculated in a multidimensional deformation space. In addition to the ground-state (GS) and the superdeformed (SD) minima, all the investigated forces yielded a hyperdeformed (HD) minimum. The contour map of the shell-plus-pairing energy clearly displayed the three minima. We found that the GS binding energy and the deformation energy of the different deformation modes along the fission path increase with the incompressibility coefficient K0, while the fission barrier heights and the excitation energies of the SD and HD modes decrease with it. Conversely, the surface-energy coefficient asurf, the symmetry-energy, and its density-slope parameter decrease the GS energy and the deformation energies, but increase the fission barrier heights and the excitation energies. The obtained deformation parameters of the different deformation modes exhibit almost independence on K0, and on the symmetry-energy and its density-slope. The principle deformation parameters of the SD and HD isomeric states tend to decrease with asurf.

Iron deposits in post-mortem brains of patients with neurodegenerative and cerebrovascular diseases: a semi-quantitative 7.0 T magnetic resonance imaging study.

PubMed

De Reuck, J L; Deramecourt, V; Auger, F; Durieux, N; Cordonnier, C; Devos, D; Defebvre, L; Moreau, C; Caparros-Lefebvre, D; Leys, D; Maurage, C A; Pasquier, F; Bordet, R

2014-07-01

Accumulation of iron (Fe) is often detected in brains of people suffering from neurodegenerative diseases. However, no studies have compared the Fe load between these disease entities. The present study investigates by T2*-weighted gradient-echo 7.0 T magnetic resonance imaging (MRI) the Fe content in post-mortem brains with different neurodegenerative and cerebrovascular diseases. One hundred and fifty-two post-mortem brains, composed of 46 with Alzheimer's disease (AD), 37 with frontotemporal lobar degeneration (FTLD), 11 with amyotrophic lateral sclerosis, 13 with Lewy body disease, 14 with progressive supranuclear palsy, 16 with vascular dementia (VaD) and 15 controls without a brain disease, were examined. The Fe load was determined semi-quantitatively on T2*-weighted MRI serial brain sections in the claustrum, caudate nucleus, putamen, globus pallidus, thalamus, subthalamic nucleus, hippocampus, mamillary body, lateral geniculate body, red nucleus, substantia nigra and dentate nucleus. The disease diagnosis was made on subsequent neuropathological examination. The Fe load was significantly increased in the claustrum, caudate nucleus and putamen of FTLD brains and to a lesser degree in the globus pallidus, thalamus and subthalamic nucleus. In the other neurodegenerative diseases no Fe accumulation was observed, except for a mild increase in the caudate nucleus of AD brains. In VaD brains no Fe increase was detected. Only FTLD displays a significant Fe load, suggesting that impaired Fe homeostasis plays an important role in the pathogenesis of this heterogeneous disease entity. © 2014 The Author(s) European Journal of Neurology © 2014 EAN.

Thermodynamic and Kinetic Properties of Intrinsic Defects and Mg Transmutants in 3C-SiC Determined by Density Functional Theory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hu, Shenyang Y.; Setyawan, Wahyu; Van Ginhoven, Renee M.

2014-02-20

Density functional theory (DFT) is used to calculate the thermodynamic and kinetic properties of transmutant Mg in 3C-SiC due to high-energy neutron irradiation associated with the fusion nuclear environment. The formation and binding energies of intrinsic defects, Mg-related defects, and clusters in 3C-SiC are systematically calculated. The minimum energy paths and activation energies during point defect migration and small cluster evolution are studied using a generalized solid-state elastic band (G-SSNEB) method with DFT energy calculations. Stable defect structures and possible defect migration mechanisms are identified. The evolution of binding energies during Mg2Si formation demonstrates that the formation of Mg2Si needsmore » to overcome a critical nucleus size and nucleation barrier. It is also found that a compressive stress field exists around the Mg2Si nucleus. These data are important inputs in meso- and macro-scale modeling and experiments to understand and predict the impact of Mg on phase stability, microstructure evolution, and performance of SiC and SiC-based materials during long-term neutron exposures.« less

Restoring Segmental Biomechanics Through Nucleus Augmentation: An In Vitro Study.

PubMed

Pelletier, Matthew H; Cohen, Charles S; Ducheyne, Paul; Walsh, William R

2016-12-01

In vitro biomechanical laboratory study. The purpose of this study is to evaluate a mechanical treatment to create a degenerative motion segment and the ability of nucleus augmentation to restore biomechanics. In cases with an intact annulus fibrosus, the replacement or augmentation of the nucleus pulposus alone may provide a less invasive option to restore normal biomechanics and disk height when compared with spinal fusion or total disk replacement. Laboratory testing allows these changes to be fully characterized. However, without preexisting pathology, nucleus augmentation therapies are difficult to evaluate in vitro. The present study evaluated pure moment bending and compressive biomechanics in 3 states (n=6): (1) intact, (2) after creep loading and nucleus disruption to induce degenerative biomechanical changes, and (3) after nucleus augmentation through an injectable polymer (DiscCell). Neutral zone and ROM were increased in all modes of bending after the degenerative treatment. The most sensitive mode of bending was lateral bending, with intact ROM (20.0±2.9 degrees) increased to 22.3±2.6 degrees after degenerative treatment and reduced to 18.4±1.6 degrees after injection of the polymer. All bending ROM and NZ changes induced by the degenerative treatment were reversed by nucleus augmentation. This material was shown to be effective at altering motion segment biomechanics and restoring disk height during time zero tests. This technique may provide a model to examine the time zero performance of a nucleus augmentation device/material.

Relativistic Thomas-Fermi treatment of compressed atoms and compressed nuclear matter cores of stellar dimensions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rotondo, M.; Rueda, Jorge A.; Xue, S.-S.

The Feynman-Metropolis-Teller treatment of compressed atoms is extended to the relativistic regimes. Each atomic configuration is confined by a Wigner-Seitz cell and is characterized by a positive electron Fermi energy. The nonrelativistic treatment assumes a pointlike nucleus and infinite values of the electron Fermi energy can be attained. In the relativistic treatment there exists a limiting configuration, reached when the Wigner-Seitz cell radius equals the radius of the nucleus, with a maximum value of the electron Fermi energy (E{sub e}{sup F}){sub max}, here expressed analytically in the ultrarelativistic approximation. The corrections given by the relativistic Thomas-Fermi-Dirac exchange term are alsomore » evaluated and shown to be generally small and negligible in the relativistic high-density regime. The dependence of the relativistic electron Fermi energies by compression for selected nuclei are compared and contrasted to the nonrelativistic ones and to the ones obtained in the uniform approximation. The relativistic Feynman-Metropolis-Teller approach here presented overcomes some difficulties in the Salpeter approximation generally adopted for compressed matter in physics and astrophysics. The treatment is then extrapolated to compressed nuclear matter cores of stellar dimensions with A{approx_equal}(m{sub Planck}/m{sub n}){sup 3}{approx}10{sup 57} or M{sub core}{approx}M{sub {circle_dot}}. A new family of equilibrium configurations exists for selected values of the electron Fermi energy varying in the range 0

Inclusive Prompt Photons from the Color Glass Condensate at NLO

NASA Astrophysics Data System (ADS)

Benić, Sanjin; Fukushima, Kenji; Garcia-Montero, Oscar; Venugopalan, Raju

2018-05-01

The cross-section for photons radiated by quarks in proton-nucleus collisions at collider energies was obtained using the Color Glass Condensate framework, in the dense-dilute kinematics regime. We observe that the inclusive photon cross-section is proportional to all-twist Wilson line correlators in the nucleus. These correlators also appear in quark-pair production; unlike the latter, photon production is insensitive to hadronization uncertainties and therefore more sensitive to multi-parton correlations in the gluon saturation regime of QCD.

Variational principle model for the nuclear caloric curve

DOE Office of Scientific and Technical Information (OSTI.GOV)

Das Gupta, S.

2005-12-15

Following the lead of a recent work, I perform a variational principle model calculation for the nuclear caloric curve. A Skyrme-type interaction with and without momentum dependence is used. The calculation is done for a large nucleus, i.e., in the nuclear matter limit. Thus I address the issue of volume fragmentation only. Nonetheless, the results are similar to the previous, largely phenomenological calculation for a finite nucleus. I find that the onset of fragmentation can be sudden as a function of temperature or excitation energy.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nesterov, V. A., E-mail: archerix@ukpost.ua

On the basis of the energy-density method, the effect of simultaneously taking into account the Pauli exclusion principle and the monopole and quadrupole polarizations of interacting nuclei on their interaction potential is considered for the example of the {sup 16}O + {sup 16}O system by using the wave function for the two-center shell model. The calculations performed in the adiabatic approximation reveal that the inclusion of the Pauli exclusion principle and the polarization of interacting nuclei, especially their quadrupole polarization, has a substantial effect on the potential of the nucleus-nucleus interaction.

Formation of the 50-Year Element 94 from Deuteron Bombardment of U{sup 238}

DOE R&D Accomplishments Database

Kennedy, J. W.; Perlman, M. L.; Segre, E.; Wahl, A. C.

1942-06-01

It has been shown by bombardment with deuterons of a sample of U{sup 238}, greatly depleted in U{sup 235} and U{sup 234}, that the 50-year 94 activity and 2.0 day 93 activity are formed in approximately the same yield as with the natural mixture of uranium isotopes. The activities are thus shown to arise from the U{sup 238} nucleus, and from considerations of the energy of the compound nucleus (U{sup 238} + d).

Biological and Catalytic Conversion of Sugars and Lignin Publications |

Science.gov Websites

mechanism of free and cellulosomal enzyme synergy, ACS Sustainable Chem. Eng. Evaluation of clean Free Energy, J. Amer. Chem. Soc. Process Design and Economics for the Conversion of Lignocellulosic Processive Cellulase with Multiple Absolute Binding Free Energy Methods, J. Biol. Chem. Optimizing Nucleus

The νGeN experiment at the Kalinin Nuclear Power Plant

NASA Astrophysics Data System (ADS)

Belov, V.; Brudanin, V.; Egorov, V.; Filosofov, D.; Fomina, M.; Gurov, Yu.; Korotkova, L.; Lubashevskiy, A.; Medvedev, D.; Pritula, R.; Rozova, I.; Rozov, S.; Sandukovsky, V.; Timkin, V.; Yakushev, E.; Yurkowski, J.; Zhitnikov, I.

2015-12-01

The ν GeN is new experiment at the Kalinin Nuclear Power Plant (KNPP) for detection of coherent Neutrino-Ge Nucleus elastic scattering. Recent neutrino and Dark Matter search experiments have revolutionized the detection of rear events, and rear events with low energies, in particular. Experiments have achieved sensitivities on the level of several events per hundred kg of detector material per day with energy thresholds from few hundred eV. This opens up a new unique possibility for experimental detection of neutrino-nucleus coherent scattering that has been considered to be impossible so far. The νGeN project uses low threshold high-purity Ge-detectors (HPGe) developed by JINR (Dubna, Russia) in collaboration with BSI (Baltic Scientific Instruments, Riga, Latvia) for creation of a setup designated for first observation of neutrino coherent scattering on Ge. As a powerful neutrino source the experiment will use electron antineutrinos from one of the power-generating units (reactor unit #3) of the KNPP. The coherent neutrino scattering will be observed using a differential method that compares 1) the spectra measured at the reactor operation and shut-down periods; 2) the spectra measured at different distances from the reactor core during the reactor operation. For a setup placed at a 10 m distance from the center of reactor core and with an energy threshold of 350 eV up to tens of events corresponding to neutrino coherent scattering on Ge are expected to be detected per day in the constructed setup with four HPGe low-energy-threshold detectors (~ 400 grams each). The setup sensitivity will be even more increased by using new detectors with total mass up to 5 kg.

Non-homeostatic body weight regulation through a brainstem-restricted receptor for GDF15

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hsu, Jer-Yuan; Crawley, Suzanne; Chen, Michael

Under homeostatic conditions, animals use well-defined hypothalamic neural circuits to help maintain stable body weight, by integrating metabolic and hormonal signals from the periphery to balance food consumption and energy expenditure1,2. In stressed or disease conditions, however, animals use alternative neuronal pathways to adapt to the metabolic challenges of altered energy demand3. Recent studies have identified brain areas outside the hypothalamus that are activated under these ‘non-homeostatic’ conditions4,5,6, but the molecular nature of the peripheral signals and brain-localized receptors that activate these circuits remains elusive. Here we identify glial cell-derived neurotrophic factor (GDNF) receptor alpha-like (GFRAL) as a brainstem-restricted receptormore » for growth and differentiation factor 15 (GDF15). GDF15 regulates food intake, energy expenditure and body weight in response to metabolic and toxin-induced stresses; we show that Gfral knockout mice are hyperphagic under stressed conditions and are resistant to chemotherapy-induced anorexia and body weight loss. GDF15 activates GFRAL-expressing neurons localized exclusively in the area postrema and nucleus tractus solitarius of the mouse brainstem. It then triggers the activation of neurons localized within the parabrachial nucleus and central amygdala, which constitute part of the ‘emergency circuit’ that shapes feeding responses to stressful conditions7. GDF15 levels increase in response to tissue stress and injury, and elevated levels are associated with body weight loss in numerous chronic human diseases8,9. By isolating GFRAL as the receptor for GDF15-induced anorexia and weight loss, we identify a mechanistic basis for the non-homeostatic regulation of neural circuitry by a peripheral signal associated with tissue damage and stress. These findings provide opportunities to develop therapeutic agents for the treatment of disorders with altered energy demand.« less

Changes in Nutritional Status after Deep Brain Stimulation of the Nucleus Basalis of Meynert in Alzheimer's Disease--Results of a Phase I Study.

PubMed

Noreik, M; Kuhn, J; Hardenacke, K; Lenartz, D; Bauer, A; Bührle, C P; Häussermann, P; Hellmich, M; Klosterkötter, J; Wiltfang, J; Maarouf, M; Freund, H-J; Visser-Vandewalle, V; Sturm, V; Schulz, R-J

2015-10-01

The progression of Alzheimer's disease (AD) is associated with impaired nutritional status. New methods, such as deep brain stimulation (DBS), are currently being tested to decrease the progression of AD. DBS is an approved method in the treatment of Parkinson's disease, and its suitability for the treatment of AD patients is currently under experimental investigation. To evaluate the advantages and disadvantages of this new treatment, it is important to assess potential side effects of DBS regarding the nucleus basalis of Meynert; this new treatment is thought to positively affect cognition and might counteract the deterioration of nutritional status and progressive weight loss observed in AD. This study aims to assess the nutritional status of patients with AD before receiving DBS of the nucleus basalis of Meynert and after 1 year, and to analyze potential associations between changes in cognition and nutritional status. A 1-year phase I proof-of-concept study. The Department of Psychiatry and Psychotherapy at the University of Cologne. We assessed a consecutive sample of patients with mild to moderate AD (n=6) who fulfilled the inclusion criteria and provided written informed consent. Bilateral low-frequency DBS of the nucleus basalis of Meynert. Nutritional status was assessed using a modified Mini Nutritional Assessment, bioelectrical impedance analysis, a completed 3-day food diary, and analysis of serum levels of vitamin B12 and folate. With a normal body mass index (BMI) at baseline (mean 23.75 kg/m²) and after 1 year (mean 24.59 kg/m²), all but one patient gained body weight during the period of the pilot study (mean 2.38 kg, 3.81% of body weight). This was reflected in a mainly stable or improved body composition, assessed by bioelectrical impedance analysis, in five of the six patients. Mean energy intake increased from 1534 kcal/day (min 1037, max 2370) at baseline to 1736 kcal/day (min 1010, max 2663) after 1 year, leading to the improved fulfillment of energy needs in four patients. The only nutritional factors that were associated with changes in cognition were vitamin B12 level at baseline (Spearman's rho = 0.943, p = 0.005) and changes in vitamin B12 level (Spearman's rho = -0.829, p = 0.042). Patients with AD that received DBS of the nucleus basalis of Meynert demonstrated a mainly stable nutritional status within a 1-year period. Whether DBS is causative regarding these observations must be investigated in additional studies.

Study of angular momentum variation due to entrance channel effect in heavy ion fusion reactions

NASA Astrophysics Data System (ADS)

Kumar, Ajay

2014-05-01

A systematic investigation of the properties of hot nuclei may be studied by detecting the evaporated particles. These emissions reflect the behavior of the nucleus at various stages of the deexcitation cascade. When the nucleus is formed by the collision of a heavy nucleus with a light particle, the statistical model has done a good job of predicting the distribution of evaporated particles when reasonable choices were made for the level densities and yrast lines. Comparison to more specific measurements could, of course, provide a more severe test of the model and enable one to identify the deviations from the statistical model as the signature of other effects not included in the model. Some papers have claimed that experimental evaporation spectra from heavy-ion fusion reactions at higher excitation energies and angular momenta are no longer consistent with the predictions of the standard statistical model. In order to confirm this prediction we have employed two systems, a mass-symmetric (31P+45Sc) and a mass-asymmetric channel (12C+64Zn), leading to the same compound nucleus 76Kr* at the excitation energy of 75 MeV. Neutron energy spectra of the asymmetric system (12C+64Zn) at different angles are well described by the statistical model predictions using the normal value of the level density parameter a = A/8 MeV-1. However, in the case of the symmetric system (31P+45Sc), the statistical model interpretation of the data requires the change in the value of a = A/10 MeV-1. The delayed evolution of the compound system in case of the symmetric 31P+45Sc system may lead to the formation of a temperature equilibrated dinuclear complex, which may be responsible for the neutron emission at higher temperature, while the protons and alpha particles are evaporated after neutron emission when the system is sufficiently cooled down and the higher g-values do not contribute in the formation of the compound nucleus for the symmetric entrance channel in case of charged particle emission.

Neuronal plasticity in the hedgehog supraoptic nucleus during hibernation.

PubMed

Sanchez-Toscano, F; Caminero, A A; Machin, C; Abella, G

1989-01-01

The purpose of the present study was to identify processes of plasticity in the receptive field of neurosecretory neurons of the supraoptic nucleus during hibernation in the hedgehog, in order to correlate them with the increased neurosecretory activity observed in this nucleus during this annual period. Using the Rapid Golgi method, a quantitative study was conducted in the receptive field of bipolar and multipolar neurons (the main components of the nucleus). Results indicate a generalized increase in the following characteristics: (1) number of dendritic spines per millimeter along the dendritic shafts; (2) degree of branching in the dendritic field; and (3) dendritic density around the neuronal soma. These data demonstrate modification of the dendritic field in the supraoptic nucleus during hibernation, a change undoubtedly related to functional conditions. Since the observed changes affect structures such as dendritic spines which are directly related to the arrival of neural afferences, the discussion is centered on the types of stimuli which may be responsible for the observed processes.

Energy expenditure: a critical determinant of energy balance with key hypothalamic controls.

PubMed

Richard, D

2007-09-01

Energy stores are regulated through complex neural controls exerted on both food intake and energy expenditure. These controls are insured by interconnected neurons that produce different peptides or classic neurotransmitters, which have been regrouped into anabolic' and catabolic' systems. While the control of energy intake has been addressed in numerous investigations, that of energy expenditure has, as yet, only received a moderate interest, even though energy expenditure represents a key determinant of energy balance. In laboratory rodents, in particular, a strong regulatory control is exerted on brown adipose tissue (BAT), which represent an efficient thermogenic effector. BAT thermogenesis is governed by the sympathetic nervous system (SNS), whose activity is controlled by neurons comprised in various brain regions, which include the paraventricular hypothalamic nucleus (PVH), the arcuate nucleus (ARC) and the lateral hypothalamus (LH). Proopiomelanocortin neurons from the ARC project to the PVH and terminate in the vicinity of the melanocortin-4 receptors, which are concentrated in the descending division of the PVH, which comprise neurons controlling the SNS outflow to BAT. The LH contains neurons producing melanin-concentrating hormone or orexins, which also are important peptides in the control of energy expenditure. These neurons are not only polysynaptically connected to BAT, but also linked to brains regions controlling motivated behaviors and locomotor activity and, consequently, their role in the control of energy expenditure could go beyond BAT thermogenesis.

Isomer depletion as experimental evidence of nuclear excitation by electron capture

NASA Astrophysics Data System (ADS)

Chiara, C. J.; Carroll, J. J.; Carpenter, M. P.; Greene, J. P.; Hartley, D. J.; Janssens, R. V. F.; Lane, G. J.; Marsh, J. C.; Matters, D. A.; Polasik, M.; Rzadkiewicz, J.; Seweryniak, D.; Zhu, S.; Bottoni, S.; Hayes, A. B.; Karamian, S. A.

2018-02-01

The atomic nucleus and its electrons are often thought of as independent systems that are held together in the atom by their mutual attraction. Their interaction, however, leads to other important effects, such as providing an additional decay mode for excited nuclear states, whereby the nucleus releases energy by ejecting an atomic electron instead of by emitting a γ-ray. This ‘internal conversion’ has been known for about a hundred years and can be used to study nuclei and their interaction with their electrons. In the inverse process—nuclear excitation by electron capture (NEEC)—a free electron is captured into an atomic vacancy and can excite the nucleus to a higher-energy state, provided that the kinetic energy of the free electron plus the magnitude of its binding energy once captured matches the nuclear energy difference between the two states. NEEC was predicted in 1976 and has not hitherto been observed. Here we report evidence of NEEC in molybdenum-93 and determine the probability and cross-section for the process in a beam-based experimental scenario. Our results provide a standard for the assessment of theoretical models relevant to NEEC, which predict cross-sections that span many orders of magnitude. The greatest practical effect of the NEEC process may be on the survival of nuclei in stellar environments, in which it could excite isomers (that is, long-lived nuclear states) to shorter-lived states. Such excitations may reduce the abundance of the isotope after its production. This is an example of ‘isomer depletion’, which has been investigated previously through other reactions, but is used here to obtain evidence for NEEC.

Orexin receptors in the developing piglet hypothalamus, and effects of nicotine and intermittent hypercapnic hypoxia exposures.

PubMed

Hunt, Nicholas J; Waters, Karen A; Machaalani, Rita

2013-05-01

Orexin and its receptors (OxR1 and OxR2) play a significant role in arousal and sleep regulation. Using developing piglets, we aimed to determine the effects of nicotine and Intermittent Hypercapnic Hypoxia (IHH), alone or in combination, on orexin receptor expression in the hypothalamus. Four piglet groups were studied: control (n=14), nicotine (n=14), IHH (n=10) and nic+IHH (n=14). Applying immunohistochemistry for OxR1 and OxR2 expression, eight nuclei/areas of the hypothalamus: dorsal medial nucleus (DMN), arcuate nucleus (ARC), perifornical area (PFA), paraventricular nucleus (PVN), lateral hypothalamic area (LHA), ventral medial nucleus (VMN), supraoptic nucleus, retrochiasmatic part (SONr) and tuberal mammillary nucleus (TMN), were studied. Compared to controls, OxR1 and OxR2 were increased due to exposures, however this was region dependent. Nicotine increased OxR1 in the DMN (P<0.001) and SONr (P=0.036), and OxR2 in the DMN (P<0.001), VMN (P=0.014) and the TMN (P=0.026). IHH increased OxR1 in the DMN, PVN, VMN and SONr (P<0.01 for all), and OxR2 in DMN (P<0.001), PFA (P=0.001), PVN (P=0.004), VMN (P=0.041) and the TMN (P<0.001). The nic+IHH exposure increased OxR1 expression in all nuclei (TMN excluded) however, the changes were not significantly different from IHH alone. For OxR2, the increased expression after nic+IHH was significant compared to IHH in the DMN, ARC and SONr. These results show that nicotine increases orexin receptor expression in a region dependent manner. IHH induced increases were specific to arousal and stress related regions and nic+IHH results suggest that for OxR1, nicotine has no additive effect whereas for OxR2 it does, and is region dependent. Copyright © 2013 Elsevier B.V. All rights reserved.

Periodic mechanical stress activates EGFR-dependent Rac1 mitogenic signals in rat nucleus pulpous cells via ERK1/2

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gao, Gongming; Shen, Nan; Jiang, Xuefeng

2016-01-15

The mitogenic effects of periodic mechanical stress on nucleus pulpous cells have been studied extensively but the mechanisms whereby nucleus pulpous cells sense and respond to mechanical stimulation remain a matter of debate. We explored this question by performing cell culture experiments in our self-developed periodic stress field and perfusion culture system. Under periodic mechanical stress, rat nucleus pulpous cell proliferation was significantly increased (p < 0.05 for each) and was associated with increases in the phosphorylation and activation of EGFR, Rac1, and ERK1/2 (p < 0.05 for each). Pretreatment with the ERK1/2 selective inhibitor PD98059 reduced periodic mechanical stress-induced nucleus pulpous cell proliferationmore » (p < 0.05 for each), while the activation levels of EGFR and Rac1 were not inhibited. Proliferation and phosphorylation of ERK1/2 were inhibited after pretreatment with the Rac1 inhibitor NSC23766 in nucleus pulpous cells in response to periodic mechanical stress (p < 0.05 for each), while the phosphorylation site of EGFR was not affected. Inhibition of EGFR activity with AG1478 abrogated nucleus pulpous cell proliferation (p < 0.05 for each) and attenuated Rac1 and ERK1/2 activation in nucleus pulpous cells subjected to periodic mechanical stress (p < 0.05 for each). These findings suggest that periodic mechanical stress promotes nucleus pulpous cell proliferation in part through the EGFR-Rac1-ERK1/2 signaling pathway, which links these three important signaling molecules into a mitogenic cascade. - Highlights: • The mechanism involved in nucleus pulpous cells to respond to mechanical stimuli. • Periodic mechanical stress can stimulate the phosphorylation of EGFR. • EGFR activates Rac1 and leads to rat nucleus pulpous cell proliferation. • EGFR and Rac1 activate ERK1/2 mitogenic signals in nucleus pulpous cells. • EGFR-Rac1-ERK1/2 is constitutes at least one critical signal transduction pathway.« less

DNA Damage Related Crosstalk Between the Nucleus and Mitochondria

PubMed Central

Saki, Mohammad; Prakash, Aishwarya

2017-01-01

The electron transport chain is the primary pathway by which a cell generates energy in the form of ATP. Byproducts of this process produce reactive oxygen species that can cause damage to mitochondrial DNA. If not properly repaired, the accumulation of DNA damage can lead to mitochondrial dysfunction linked to several human disorders including neurodegenerative diseases and cancer. Mitochondria are able to combat oxidative DNA damage via repair mechanisms that are analogous to those found in the nucleus. Of the repair pathways currently reported in the mitochondria, the base excision repair pathway is the most comprehensively described. Proteins that are involved with the maintenance of mtDNA are encoded by nuclear genes and translocate to the mitochondria making signaling between the nucleus and mitochondria imperative. In this review, we discuss the current understanding of mitochondrial DNA repair mechanisms and also highlight the sensors and signaling pathways that mediate crosstalk between the nucleus and mitochondria in the event of mitochondrial stress. PMID:27915046

Estradiol Regulates Brown Adipose Tissue Thermogenesis via Hypothalamic AMPK

PubMed Central

Martínez de Morentin, Pablo B.; González-García, Ismael; Martins, Luís; Lage, Ricardo; Fernández-Mallo, Diana; Martínez-Sánchez, Noelia; Ruíz-Pino, Francisco; Liu, Ji; Morgan, Donald A.; Pinilla, Leonor; Gallego, Rosalía; Saha, Asish K.; Kalsbeek, Andries; Fliers, Eric; Bisschop, Peter H.; Diéguez, Carlos; Nogueiras, Rubén; Rahmouni, Kamal; Tena-Sempere, Manuel; López, Miguel

2014-01-01

Summary Estrogens play a major role in the modulation of energy balance through central and peripheral actions. Here, we demonstrate that central action of estradiol (E2) inhibits AMP-activated protein kinase (AMPK) through estrogen receptor alpha (ERα) selectively in the ventromedial nucleus of the hypothalamus (VMH), leading to activation of thermogenesis in brown adipose tissue (BAT) through the sympathetic nervous system (SNS) in a feeding-independent manner. Genetic activation of AMPK in the VMH prevented E2-induced increase in BAT-mediated thermogenesis and weight loss. Notably, fluctuations in E2 levels during estrous cycle also modulate this integrated physiological network. Together, these findings demonstrate that E2 regulation of the VMH AMPK-SNS-BAT axis is an important determinant of energy balance and suggest that dysregulation in this axis may account for the common changes in energy homeostasis and obesity linked to dysfunction of the female gonadal axis. PMID:24856932

Differential expression of cocaine- and amphetamine-regulated transcript and agouti related-protein in chronically food-restricted sheep.

PubMed

Henry, B A; Rao, A; Ikenasio, B A; Mountjoy, K G; Tilbrook, A J; Clarke, I J

2001-11-09

Recently, much attention has focused on the role of the melanocortin system in the regulation of energy homeostasis, especially the satiety effects of the pro-opiomelanocortin (POMC)-derived peptide alpha-melanocyte stimulating hormone (alpha-MSH). We have found that POMC mRNA levels are similar in fat and thin sheep and the current study sought to further characterize the effects of nutritional status on the melanocortin system. To this end, we studied the expression of agouti-related peptide (AGRP) (an endogenous antagonist of alpha-MSH) and cocaine- and amphetamine-regulated transcript (CART), which is co-localized within POMC cells of the arcuate nucleus (ARC) in rodents. Twelve ovariectomized ewes were randomly divided into two groups and fed a maintenance (n=6) or restricted diet (n=6). At the time of experimentation, the animals had significantly (P<0.0001) different bodyweights (53.4+/-2.2 kg, ad libitum vs. 30.4+/-1.2 kg, food-restricted), which was largely due to altered body fat deposits. In situ hybridization was used to study the expression of POMC, AGRP and CART. The expression of POMC in the ARC was similar in ad libitum and food-restricted animals but the expression of AGRP was profoundly increased in the food-restricted group. The expression of CART was abundant throughout the hypothalamus but was not found in the ARC. In food-restricted animals, the expression of CART was lower in the retrochiasmatic nucleus (P<0.01), paraventricular nucleus (P<0.001), the dorsomedial nucleus and the lateral hypothalamic area (P<0.05), but was higher (P<0.01) in the posterior hypothalamic area. Thus, long-term changes in nutritional status have profound effects on the expression of AGRP and CART in the hypothalamus.

Measurement of Plutonium-240 Angular Momentum Dependent Fission Probabilities Using the Alpha-Alpha' Reaction

NASA Astrophysics Data System (ADS)

Koglin, Johnathon

Accurate nuclear reaction data from a few keV to tens of MeV and across the table of nuclides is essential to a number of applications of nuclear physics, including national security, nuclear forensics, nuclear astrophysics, and nuclear energy. Precise determination of (n, f) and neutron capture cross sections for reactions in high- ux environments are particularly important for a proper understanding of nuclear reactor performance and stellar nucleosynthesis. In these extreme environments reactions on short-lived and otherwise difficult-to-produce isotopes play a significant role in system evolution and provide insights into the types of nuclear processes taking place; a detailed understanding of these processes is necessary to properly determine cross sections far from stability. Indirect methods are often attempted to measure cross sections on isotopes that are difficult to separate in a laboratory setting. Using the surrogate approach, the same compound nucleus from the reaction of interest is created through a "surrogate" reaction on a different isotope and the resulting decay is measured. This result is combined with appropriate reaction theory for compound nucleus population, from which the desired cross sections can be inferred. This method has shown promise, but the theoretical framework often lacks necessary experimental data to constrain models. In this work, dual arrays of silicon telescope particle identification detectors and photovoltaic (solar) cell fission fragment detectors have been used to measure the fission probability of the 240Pu(alpha, alpha'f) reaction - a surrogate for the 239Pu(n, f) - and fission of 35.9(2)MeV at eleven scattering angles from 40° to 140° in 10° intervals and at nuclear excitation energies up to 16MeV. Within experimental uncertainty, the maximum fission probability was observed at the neutron separation energy for each alpha scattering angle. Fission probabilities were separated into five 500 keV bins from 5:5MeV to 8:0MeV and one bin from 4:5MeV to 5:5MeV. Across energy bins the fission probability increases approximately linearly with increasing alpha' scattering angle. At 90° the fission probability increases from 0:069(6) in the lowest energy bin to 0:59(2) in the highest. Likewise, within a single energy bin the fission probability increases with alpha' scattering angle. Within the 6:5MeV and 7:0MeV energy bin, the fission probability increased from 0:41(1) at 60° to 0:81(10) at 140°. Fission fragment angular distributions were also measured integrated over each energy bin. These distributions were fit to theoretical distributions based on combinations of transitional nuclear vibrational and rotational excitations at the saddle point. Contributions from specific K vibrational states were extracted and combined with fission probability measurements to determine the relative fission probability of each state as a function of nuclear excitation energy. Within a given excitation energy bin, it is found that contributions from K states greater than the minimum K = 0 state tend to increase with the increasing alpha' scattering angle. This is attributed to an increase in the transferred angular momentum associated with larger scattering angles. The 90° alpha' scattering angle produced the highest quality results. The relative contributions of K states do not show a discernible trend across the energy spectrum. The energy-binned results confirm existing measurements that place a K = 2 state in the first energy bin with the opening of K = 1 and K = 4 states at energies above 5:5MeV. This experiment represents the first of its kind in which fission probabilities and angular distributions are simultaneously measured at a large number of scattering angles. The acquired fission probability, angular distribution, and K state contribution provide a diverse dataset against which microscopic fission models can be constrained and further the understanding of the properties of the 240Pu fission.

Glutamate Receptors in the Central Nucleus of the Amygdala Mediate Cisplatin-Induced Malaise and Energy Balance Dysregulation through Direct Hindbrain Projections

PubMed Central

Alhadeff, Amber L.; Holland, Ruby A.; Nelson, Alexandra; Grill, Harvey J.

2015-01-01

Cisplatin chemotherapy is used commonly to treat a variety of cancers despite severe side effects such as nausea, vomiting, and anorexia that compromise quality of life and limit treatment adherence. The neural mechanisms mediating these side effects remain elusive despite decades of clinical use. Recent data highlight the dorsal vagal complex (DVC), lateral parabrachial nucleus (lPBN), and central nucleus of the amygdala (CeA) as potential sites of action in mediating the side effects of cisplatin. Here, results from immunohistochemical studies in rats identified a population of cisplatin-activated DVC neurons that project to the lPBN and a population of cisplatin-activated lPBN calcitonin gene-related peptide (CGRP, a marker for glutamatergic neurons in the lPBN) neurons that project to the CeA, outlining a neuroanatomical circuit that is activated by cisplatin. CeA gene expressions of AMPA and NMDA glutamate receptor subunits were markedly increased after cisplatin treatment, suggesting that CeA glutamate receptor signaling plays a role in mediating cisplatin side effects. Consistent with gene expression results, behavioral/pharmacological data showed that CeA AMPA/kainate receptor blockade attenuates cisplatin-induced pica (a proxy for nausea/behavioral malaise in nonvomiting laboratory rodents) and that CeA NMDA receptor blockade attenuates cisplatin-induced anorexia and body weight loss in addition to pica, demonstrating that glutamate receptor signaling in the CeA is critical for the energy balance dysregulation caused by cisplatin treatment. Together, these data highlight a novel circuit and CGRP/glutamatergic mechanism through which cisplatin-induced malaise and energy balance dysregulation are mediated. SIGNIFICANCE STATEMENT To treat cancer effectively, patients must follow prescribed chemotherapy treatments without interruption, yet most cancer treatments produce side effects that devastate quality of life (e.g., nausea, vomiting, anorexia, weight loss). Although hundreds of thousands of patients undergo chemotherapies each year, the neural mechanisms mediating their side effects are unknown. The current data outline a neural circuit activated by cisplatin chemotherapy and demonstrate that glutamate signaling in the amygdala, arising from hindbrain projections, is required for the full expression of cisplatin-induced malaise, anorexia, and body weight loss. Together, these data help to characterize the neural circuits and neurotransmitters mediating chemotherapy-induced energy balance dysregulation, which will ultimately provide an opportunity for the development of well tolerated cancer and anti-emetic treatments. PMID:26245970

Direct observation of nanoparticle-cancer cell nucleus interactions.

PubMed

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

2012-04-24

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

Comprehensive track-structure based evaluation of DNA damage by light ions from radiotherapy-relevant energies down to stopping

PubMed Central

Friedland, W.; Schmitt, E.; Kundrát, P.; Dingfelder, M.; Baiocco, G.; Barbieri, S.; Ottolenghi, A.

2017-01-01

Track structures and resulting DNA damage in human cells have been simulated for hydrogen, helium, carbon, nitrogen, oxygen and neon ions with 0.25–256 MeV/u energy. The needed ion interaction cross sections have been scaled from those of hydrogen; Barkas scaling formula has been refined, extending its applicability down to about 10 keV/u, and validated against established stopping power data. Linear energy transfer (LET) has been scored from energy deposits in a cell nucleus; for very low-energy ions, it has been defined locally within thin slabs. The simulations show that protons and helium ions induce more DNA damage than heavier ions do at the same LET. With increasing LET, less DNA strand breaks are formed per unit dose, but due to their clustering the yields of double-strand breaks (DSB) increase, up to saturation around 300 keV/μm. Also individual DSB tend to cluster; DSB clusters peak around 500 keV/μm, while DSB multiplicities per cluster steadily increase with LET. Remarkably similar to patterns known from cell survival studies, LET-dependencies with pronounced maxima around 100–200 keV/μm occur on nanometre scale for sites that contain one or more DSB, and on micrometre scale for megabasepair-sized DNA fragments. PMID:28345622

Spin distributions and cross sections of evaporation residues in the 28Si+176Yb reaction

NASA Astrophysics Data System (ADS)

Sudarshan, K.; Tripathi, R.; Sodaye, S.; Sharma, S. K.; Pujari, P. K.; Gehlot, J.; Madhavan, N.; Nath, S.; Mohanto, G.; Mukul, I.; Jhingan, A.; Mazumdar, I.

2017-02-01

Background: Non-compound-nucleus fission in the preactinide region has been an active area of investigation in the recent past. Based on the measurements of fission-fragment mass distributions in the fission of 202Po, populated by reactions with varying entrance channel mass asymmetry, the onset of non-compound-nucleus fission was proposed to be around ZpZt˜1000 [Phys. Rev. C 77, 024606 (2008), 10.1103/PhysRevC.77.024606], where Zp and Zt are the projectile and target proton numbers, respectively. Purpose: The present paper is aimed at the measurement of cross sections and spin distributions of evaporation residues in the 28Si+176Yb reaction (ZpZt=980 ) to investigate the fusion hindrance which, in turn, would give information about the contribution from non-compound-nucleus fission in this reaction. Method: Evaporation-residue cross sections were measured in the beam energy range of 129-166 MeV using the hybrid recoil mass analyzer (HYRA) operated in the gas-filled mode. Evaporation-residue cross sections were also measured by the recoil catcher technique followed by off-line γ -ray spectrometry at few intermediate energies. γ -ray multiplicities of evaporation residues were measured to infer about their spin distribution. The measurements were carried out using NaI(Tl) detector-based 4π-spin spectrometer from the Tata Institute of Fundamental Research, Mumbai, coupled to the HYRA. Results: Evaporation-residue cross sections were significantly lower compared to those calculated using the statistical model code pace2 [Phys. Rev. C 21, 230 (1980), 10.1103/PhysRevC.21.230] with the coupled-channel fusion model code ccfus [Comput. Phys. Commun. 46, 187 (1987), 10.1016/0010-4655(87)90045-2] at beam energies close to the entrance channel Coulomb barrier. At higher beam energies, experimental cross sections were close to those predicted by the model. Average γ -ray multiplicities or angular momentum values of evaporation residues were in agreement with the calculations of the code ccfus + pace2 within the experimental uncertainties at all the beam energies. Conclusions: Deviation of evaporation-residue cross sections from the "fusion + statistical model" predictions at beam energies close to the entrance channel Coulomb barrier indicates fusion hindrance at these beam energies which would lead to non-compound-nucleus fission. However, reasonable agreement of average angular momentum values of evaporation residues at these beam energies with those calculated using the coupled-channel fusion model with the statistical model codes ccfus + pace2 suggests that fusion suppression at beam energies close to the entrance channel Coulomb barrier where populated l waves are low is not l dependent.

Excitatory innervation of caudal hypoglossal nucleus from nucleus reticularis gigantocellularis in the rat.

PubMed

Yang, C C; Chan, J Y; Chan, S H

1995-03-01

We examined the possible innervation of the caudal hypoglossal nucleus by the nucleus reticularis gigantocellularis of the medulla oblongata, based on single-neuron recording and retrograde tracing experiments in Sprague-Dawley rats. Under pentobarbital sodium (50 mg/kg, i.p.) anesthesia, electrical stimulation of the caudal portion of the nucleus reticularis gigantocellularis with repetitive 0.5-ms rectangular pulses increased (46 of 51 neurons) the basal discharge frequency of spontaneously active cells, or evoked spike activity in silent, hypoglossal neurons located at the level of the obex. This excitatory effect was related to the intensity (25-100 microA) and/or frequency (0.5-20 Hz) of the stimulating pulses to the nucleus reticularis gigantocellularis. Perikaryal activation of neurons by microinjection of L-glutamate (0.5 nmol, 25 nl) into the caudal portion of the nucleus reticularis gigantocellularis similarly produced an excitatory action on eight of 14 hypoglossal neurons. Retrogradely labeled neurons were found bilaterally within the confines of the nucleus reticularis gigantocellularis following unilateral microinjection of wheatgerm agglutinin-conjugated horseradish peroxidase or Fast Blue into the corresponding hypoglossal recording sites. Furthermore, the distribution of labeled neurons in the nucleus reticularis gigantocellularis substantially overlapped with the loci of electrical or chemical stimulation. These complementary electrophysiological and neuroanatomical results support the conclusion that an excitatory link exists between the nucleus reticularis gigantocellularis and at least the caudal portion of the hypoglossal nucleus in the rat.

Fusion of deformed nuclei in the reactions of 76Ge+150Nd and 28Si+198Pt at the Coulomb barrier region

NASA Astrophysics Data System (ADS)

Nishio, K.; Ikezoe, H.; Mitsuoka, S.; Lu, J.

2000-07-01

Evaporation residue cross sections for 28Si+198Pt and 76Ge+150Nd, both of which form a compound nucleus 226U, were measured in the vicinity of the Coulomb barrier. The measurement gives direct evidence that the system really fuses together to form a fully equilibrated compound nucleus. For the 28Si+198Pt reaction, we have measured the fission fragments to determine the fusion cross section by taking advantage of the highly fissile character of 226U. The evaporation residue cross section and the fusion cross section for 28Si+198Pt allowed us to investigate the deexcitation process (exit channel) of the compound nucleus 226U, and the parameters entering in a statistical model calculation could be determined. By estimating the deexcitation of the compound nucleus 226U with the statistical model, the effect of the deformed nucleus 150Nd on the fusion reaction 76Ge+150Nd was extracted. The experimental data indicated that there is more than 13 MeV extra-extra-push energy for the system to fuse together when the projectile 76Ge collides at the tip of the deformed 150Nd nucleus. On the contrary, for the side collision which is more compact in configuration than the tip collision, no fusion hindrance is suggested.

[Ultrasonic measurements of fetal thalamus, caudate nucleus and lenticular nucleus in prenatal diagnosis].

PubMed

Yang, Ruiqi; Wang, Fei; Zhang, Jialing; Zhu, Chonglei; Fan, Limei

2015-05-19

To establish the reference values of thalamus, caudate nucleus and lenticular nucleus diameters through fetal thalamic transverse section. A total of 265 fetuses at our hospital were randomly selected from November 2012 to August 2014. And the transverse and length diameters of thalamus, caudate nucleus and lenticular nucleus were measured. SPSS 19.0 statistical software was used to calculate the regression curve of fetal diameter changes and gestational weeks of pregnancy. P < 0.05 was considered as having statistical significance. The linear regression equation of fetal thalamic length diameter and gestational week was: Y = 0.051X+0.201, R = 0.876, linear regression equation of thalamic transverse diameter and fetal gestational week was: Y = 0.031X+0.229, R = 0.817, linear regression equation of fetal head of caudate nucleus length diameter and gestational age was: Y = 0.033X+0.101, R = 0.722, linear regression equation of fetal head of caudate nucleus transverse diameter and gestational week was: R = 0.025 - 0.046, R = 0.711, linear regression equation of fetal lentiform nucleus length diameter and gestational week was: Y = 0.046+0.229, R = 0.765, linear regression equation of fetal lentiform nucleus diameter and gestational week was: Y = 0.025 - 0.05, R = 0.772. Ultrasonic measurement of diameter of fetal thalamus caudate nucleus, and lenticular nucleus through thalamic transverse section is simple and convenient. And measurements increase with fetal gestational weeks and there is linear regression relationship between them.

Acute and repeated ECS treatment increases CRF, POMC and PENK gene expression in selected regions of the rat hypothalamus.

PubMed

Garcia-Garcia, L; Llewellyn-Jones, V; Fernandez Fernandez, I; Fuentes, J A; Manzanares, J

1998-01-05

The purpose of this study was to investigate the effects of acute and repeated electroconvulsive shock (ECS) on corticotropin releasing factor (CRF), proopiomelanocortin (POMC) and proenkephalin (PENK) gene expression in selected regions of the brain and pituitary of the rat. Acute ECS increased CRF gene expression in the paraventricular nucleus (PVN) by 20%, an effect that was further enhanced to 38% when rats received repeated ECS treatment. Acute and repeated ECS increased POMC gene expression in the arcuate nucleus (ARC) by 49-59% but failed to alter these mRNA levels in the anterior lobe (AL) of the pituitary gland. PENK gene expression was increased by 35% in the nucleus accumbens (NA) and by 180% the ventromedial nucleus (VMN) after acute or repeated ECS treatment but no significant changes were found in the PVN or striatum (ST). Taken together, these results indicate a differential CRF and opioid gene expression regulation after acute or repeated ECS treatment that may be relevant to their therapeutic or side effects in depression.

Energy metabolism of intervertebral disc under mechanical loading.

PubMed

Wang, Chong; Gonzales, Silvia; Levene, Howard; Gu, Weiyong; Huang, Chun-Yuh Charles

2013-11-01

Intervertebral disc (IVD) degeneration is closely associated with low back pain (LBP), which is a major health concern in the U.S. Cellular biosynthesis of extracellular matrix (ECM), which is important for maintaining tissue integrity and preventing tissue degeneration, is an energy demanding process. Due to impaired nutrient support in avascular IVD, adenosine triphosphate (ATP) supply could be a limiting factor for maintaining normal ECM synthesis. Therefore, the objective of this study was to investigate the energy metabolism in the annulus fibrosus (AF) and nucleus pulposus (NP) of porcine IVD under static and dynamic compressions. Under compression, pH decreased and the contents of lactate and ATP increased significantly in both AF and NP regions, suggesting that compression can promote ATP production via glycolysis and reduce pH by increasing lactate accumulation. A high level of extracellular ATP content was detected in the NP region and regulated by compressive loading. Since ATP can serve not only as an intra-cellular energy currency, but also as a regulator of a variety of cellular activities extracellularly through the purinergic signaling pathway, our findings suggest that compression-mediated ATP metabolism could be a novel mechanobiological pathway for regulating IVD metabolism. © 2013 Orthopaedic Research Society.

Instabilities in a nonstationary model of self-gravitating disks. III. The phenomenon of lopsidedness and a comparison of perturbation modes

NASA Astrophysics Data System (ADS)

Mirtadjieva, K. T.; Nuritdinov, S. N.; Ruzibaev, J. K.; Khalid, Muhammad

2011-06-01

This is an examination of the gravitational instability of the major large-scale perturbation modes for a fixed value of the azimuthal wave number m = 1 in nonlinearly nonstationary disk models with isotropic and anisotropic velocity diagrams for the purpose of explaining the displacement of the nucleus away from the geometric center (lopsidedness) in spiral galaxies. Nonstationary analogs of the dispersion relations for these perturbation modes are obtained. Critical diagrams of the initial virial ratio are constructed from the rotation parameters for the models in each case. A comparative analysis is made of the instability growth rates for the major horizontal perturbation modes in terms of two models, and it is found that, on the average, the instability growth rate for the m = 1 mode with a radial wave number N = 3 almost always has a clear advantage relative to the other modes. An analysis of these results shows that if the initial total kinetic energy in an isotropic model is no more than 12.4% of the initial potential energy, then, regardless of the value of the rotation parameter Ω, an instability of the radial motions always occurs and causes the nucleus to shift away from the geometrical center. This instability is aperiodic when Ω = 0 and is oscillatory when Ω ≠ 0 . For the anisotropic model, this kind of structure involving the nucleus develops when the initial total kinetic energy in the model is no more than 30.6% of the initial potential energy.

The Gamow-state description of the decay energy spectrum of neutron-unbound 25O

NASA Astrophysics Data System (ADS)

Id Betan, R. M.; de la Madrid, R.

2018-02-01

We show the feasibility of calculating the decay energy spectrum of neutron emitting nuclei within the Gamow-state description of resonances by obtaining the decay energy spectrum of 25O. We model this nucleus as a valence neutron interacting with an 24O inert core, and we obtain the resulting resonant energies, widths and decay energy spectra for the ground and first excited states. We also discuss the similarities and differences between the decay energy spectrum of a Gamow state and the Breit-Wigner distribution with energy-dependent width.

A leptin-regulated circuit controls glucose mobilization during noxious stimuli.

PubMed

Flak, Jonathan N; Arble, Deanna; Pan, Warren; Patterson, Christa; Lanigan, Thomas; Goforth, Paulette B; Sacksner, Jamie; Joosten, Maja; Morgan, Donald A; Allison, Margaret B; Hayes, John; Feldman, Eva; Seeley, Randy J; Olson, David P; Rahmouni, Kamal; Myers, Martin G

2017-08-01

Adipocytes secrete the hormone leptin to signal the sufficiency of energy stores. Reductions in circulating leptin concentrations reflect a negative energy balance, which augments sympathetic nervous system (SNS) activation in response to metabolically demanding emergencies. This process ensures adequate glucose mobilization despite low energy stores. We report that leptin receptor-expressing neurons (LepRb neurons) in the periaqueductal gray (PAG), the largest population of LepRb neurons in the brain stem, mediate this process. Application of noxious stimuli, which often signal the need to mobilize glucose to support an appropriate response, activated PAG LepRb neurons, which project to and activate parabrachial nucleus (PBN) neurons that control SNS activation and glucose mobilization. Furthermore, activating PAG LepRb neurons increased SNS activity and blood glucose concentrations, while ablating LepRb in PAG neurons augmented glucose mobilization in response to noxious stimuli. Thus, decreased leptin action on PAG LepRb neurons augments the autonomic response to noxious stimuli, ensuring sufficient glucose mobilization during periods of acute demand in the face of diminished energy stores.

Sequential character of low-energy ternary and quaternary nuclear fission

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kadmensky, S. G., E-mail: kadmensky@phys.vsu.ru; Bulychev, A. O.

2016-09-15

An analysis of low-energy true ternary (quaternary) nuclear fission leads to the conclusion that these fission modes have a sequential two-step (three-step) character such that the emission of a third particle (third and fourth particles) and the separation of fission fragments occur at distinctly different instants, in contrast to the simultaneous emergence of all fission products in the case of onestep ternary (quaternary) fission. This conclusion relies on the following arguments. First, the emission of a third particle (third and fourth particles) from a fissile nucleus is due to a nonevaporative mechanism associated with a nonadiabatic character of the collectivemore » deformation motion of this nucleus at the stages preceding its scission. Second, the axial symmetry of the deformed fissile compound nucleus and the direction of its symmetry axis both remain unchanged at all stages of ternary (quaternary) fission. This circumstancemakes it possible to explain themechanism of the appearance of observed anisotropies and T — odd asymmeries in the angular distributions of products of ternary (quaternary) nuclear fission. Third, the T —odd asymmetry discovered experimentally in ternary nuclear fission induced by cold polarized neutrons obeys the T —invariance condition only in the case of a sequential two-step (three-step) character of true ternary (quaternary) nuclear fission. At the same time, this asymmetry is not a T —invariant quantity in the case of the simultaneous emission of products of true ternary (quaternary) nuclear fission from the fissile compound nucleus.« less

Regulatory interactions of stress and reward on rat forebrain opioidergic and GABAergic circuitry

PubMed Central

Christiansen, A.M.; Herman, J.P.; Ulrich-Lai, Y.M.

2011-01-01

Palatable food intake reduces stress responses, suggesting that individuals may consume such “comfort” food as self-medication for stress relief. The mechanism by which palatable foods provide stress relief is not known, but likely lies at the intersection of forebrain reward and stress regulatory circuits. Forebrain opioidergic and gamma-aminobutyric acid (GABA)ergic signaling is critical for both reward and stress regulation suggesting that these systems are prime candidates for mediating stress relief by palatable foods. Thus, the current study aimed to determine 1) how palatable “comfort” food alters stress induced changes in the mRNA expression of inhibitory neurotransmitters in reward and stress neurocircuitry, and 2) identify candidate brain regions that may underlie comfort food-mediated stress reduction. We used a model of palatable “snacking” in combination with a model of chronic variable stress followed by in situ hybridization to determine forebrain levels of pro-opioid and glutamic acid decarboxylase (GAD) mRNA. The data identify regions within the extended amygdala, striatum, and hypothalamus as potential regions for mediating hypothalamic-pituitary-adrenal axis (HPA)-buffering following palatable snacking. Specifically, palatable snacking alone decreased enkephalin mRNA expression in the anterior bed nucleus of the stria terminalis and the nucleus accumbens, as well as decreasing GAD65 mRNA in the posterior bed nucleus of the stria terminalis. Chronic stress alone increased enkephalin mRNA in the hypothalamus, nucleus accumbens, amygdala, and hippocampus; increased dynorphin mRNA in the nucleus accumbens; increased GAD65 mRNA in the anterior hypothalamus and bed nucleus of the stria terminalis; and decreased GAD65 mRNA in the dorsal hypothalamus. Importantly, palatable food intake prevented stress-induced gene expression changes in subregions of the hypothalamus, bed nucleus of the stria terminalis, and nucleus accumbens. Overall, these data suggest that complex interactions exist between brain reward and stress pathways and that palatable snacking can mitigate many of the neurochemical alterations induced by chronic stress. PMID:21291318

Dynamical approach to heavy-ion induced fusion using actinide target

NASA Astrophysics Data System (ADS)

Aritomo, Y.; Hagino, K.; Chiba, S.; Nishio, K.

2012-10-01

To treat heavy-ion reactions using actinide target nucleus, we propose a model which takes into account the coupling to the collective states of interacting nuclei in the penetration of the Coulomb barrier and the dynamical evolution of nuclear shape from the contact configuration. A fluctuation-dissipation model (Langevin equation) was applied in the dynamical calculation, where effect of nuclear orientation at the initial impact on the prolately deformed target nucleus was considered. Using this model, we analyzed the experimental data for the mass distribution of fission fragments (MDFF) in the reaction of 36S+238U at several incident energies. Fusion-fission, quasifission and deep-quasi-fission are separated as different trajectories on the potential energy surface. We estimated the fusion cross section of the reaction.

Neutrino-nucleus interactions at the LBNF near detector

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mosel, Ulrich

2015-10-15

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

Tracing the origin of azimuthal gluon correlations in the color glass condensate

DOE PAGES

Lappi, T.; Schenke, B.; Schlichting, S.; ...

2016-01-11

Here we examine the origins of azimuthal correlations observed in high energy proton-nucleus collisions by considering the simple example of the scattering of uncorrelated partons off color fields in a large nucleus. We demonstrate how the physics of fluctuating color fields in the color glass condensate (CGC) effective theory generates these azimuthal multiparticle correlations and compute the corresponding Fourier coefficients v n within different CGC approximation schemes. We discuss in detail the qualitative and quantitative differences between the different schemes. Lastly, we will show how a recently introduced color field domain model that captures key features of the observed azimuthalmore » correlations can be understood in the CGC effective theory as a model of non-Gaussian correlations in the target nucleus.« less

Recent results from the strong interactions program of NA61/SHINE

NASA Astrophysics Data System (ADS)

Pulawski, Szymon

2017-12-01

The NA61/SHINE experiment studies hadron production in hadron+hadron, hadron+nucleus and nucleus+nucleus collisions. The strong interactions program has two main purposes: study the properties of the onset of deconfinement and search for the signatures of the critical point of strongly interacting matter. This aim is pursued by performing a two-dimensional scan of the phase diagram by varying the energy/momentum (13A-158A GeV/c) and the system size (p+p, Be+Be, Ar+Sc, Xe+La) of the collisions. This publication reviews recent results from p+p, Be+Be and Ar+Sc interactions. Measured particle spectra are discussed and compared to NA49 results from Pb+Pb collisions. The results illustrate the progress towards scanning the phase diagram of strongly interacting matter.

Hypothalamic AMPK and fatty acid metabolism mediate thyroid regulation of energy balance.

PubMed

López, Miguel; Varela, Luis; Vázquez, María J; Rodríguez-Cuenca, Sergio; González, Carmen R; Velagapudi, Vidya R; Morgan, Donald A; Schoenmakers, Erik; Agassandian, Khristofor; Lage, Ricardo; Martínez de Morentin, Pablo Blanco; Tovar, Sulay; Nogueiras, Rubén; Carling, David; Lelliott, Christopher; Gallego, Rosalía; Oresic, Matej; Chatterjee, Krishna; Saha, Asish K; Rahmouni, Kamal; Diéguez, Carlos; Vidal-Puig, Antonio

2010-09-01

Thyroid hormones have widespread cellular effects; however it is unclear whether their effects on the central nervous system (CNS) contribute to global energy balance. Here we demonstrate that either whole-body hyperthyroidism or central administration of triiodothyronine (T3) decreases the activity of hypothalamic AMP-activated protein kinase (AMPK), increases sympathetic nervous system (SNS) activity and upregulates thermogenic markers in brown adipose tissue (BAT). Inhibition of the lipogenic pathway in the ventromedial nucleus of the hypothalamus (VMH) prevents CNS-mediated activation of BAT by thyroid hormone and reverses the weight loss associated with hyperthyroidism. Similarly, inhibition of thyroid hormone receptors in the VMH reverses the weight loss associated with hyperthyroidism. This regulatory mechanism depends on AMPK inactivation, as genetic inhibition of this enzyme in the VMH of euthyroid rats induces feeding-independent weight loss and increases expression of thermogenic markers in BAT. These effects are reversed by pharmacological blockade of the SNS. Thus, thyroid hormone-induced modulation of AMPK activity and lipid metabolism in the hypothalamus is a major regulator of whole-body energy homeostasis.

Hypothalamic AMPK and fatty acid metabolism mediate thyroid regulation of energy balance

PubMed Central

López, Miguel; Varela, Luis; Vázquez, María J.; Rodríguez-Cuenca, Sergio; González, Carmen R.; Velagapudi, Vidya R.; Morgan, Donald A.; Schoenmakers, Erik; Agassandian, Khristofor; Lage, Ricardo; de Morentin, Pablo Blanco Martínez; Tovar, Sulay; Nogueiras, Rubén; Carling, David; Lelliott, Christopher; Gallego, Rosalía; Orešič, Matej; Chatterjee, Krishna; Saha, Asish K.; Rahmouni, Kamal; Diéguez, Carlos; Vidal-Puig, Antonio

2010-01-01

Thyroid hormones have widespread cellular effects; however it is unclear whether their effects on the central nervous system (CNS) contribute to global energy balance. Here, we demonstrate that either whole body hyperthyroidism or central administration of triiodothyronine (T3) decreases the activity of hypothalamic AMP-activated protein kinase (AMPK), increases sympathetic nervous system (SNS) activity and upregulates thermogenic markers in brown adipose tissue (BAT). Inhibition of the lipogenic pathway in the ventromedial nucleus of the hypothalamus (VMH) prevents CNS-mediated activation of BAT by thyroid hormone and reverses the weight loss associated with hyperthyroidism. Similarly inhibition of thyroid hormone receptors (TRs) in the VMH reverses the weight loss associated with hyperthyroidism. This regulatory mechanism depends on AMPK inactivation as genetic ablation of this enzyme in the VMH of euthyroid rats induces feeding-independent weight loss and increases expression of thermogenic markers in BAT. These effects are reversed by pharmacological blockade of the SNS. Thus, thyroid-hormone-induced modulation of AMPK activity and lipid metabolism in the hypothalamus is an important regulator of energy homeostasis. PMID:20802499

Neuropeptide Y and peptide YY: important regulators of energy metabolism.

PubMed

Nguyen, Amy D; Herzog, Herbert; Sainsbury, Amanda

2011-02-01

An overview of recent developments documenting the neuropeptide Y (NPY) family's role in energy metabolism. Specifically focusing on site-specific functions of NPY and increasing evidence of peptide YY (PYY) as a weight loss therapeutic. Studying the NPY family in hypothalamic nuclei, other than the arcuate and paraventricular nuclei, is a recent shift in metabolic research. NPY overexpression in the dorsomedial hypothalamus increases food intake whereas its ablation in this area reduces hyperphagia and obesity. Similarly, NPY exerts orexigenic effects in the ventromedial nucleus. However, specific arcuate Y2 receptor ablation leads to positive energy balance, suggesting the NPY family demonstrates location-specific functions. Peripherally, dual blockade of cannabinoid and NPY pathways has synergistic effects on weight loss, as does combined administration of PYY3-36 and oxyntomodulin in reducing food intake, perhaps due to the recently discovered role of PYY in mediating intestinal Gpr119 activity and controlling glucose tolerance. Conditional Y receptor knockout models have provided deeper insights on NPY's functions according to location. Further study of PYY appears vital, due to recent evidence of its role in intestinal motility, with exercise positively influencing PYY levels.

Directed Communication between Nucleus Accumbens and Neocortex in Humans Is Differentially Supported by Synchronization in the Theta and Alpha Band.

PubMed

Horschig, Jörn M; Smolders, Ruud; Bonnefond, Mathilde; Schoffelen, Jan-Mathijs; van den Munckhof, Pepijn; Schuurman, P Richard; Cools, Roshan; Denys, Damiaan; Jensen, Ole

2015-01-01

Here, we report evidence for oscillatory bi-directional interactions between the nucleus accumbens and the neocortex in humans. Six patients performed a demanding covert visual attention task while we simultaneously recorded brain activity from deep-brain electrodes implanted in the nucleus accumbens and the surface electroencephalogram (EEG). Both theta and alpha oscillations were strongly coherent with the frontal and parietal EEG during the task. Theta-band coherence increased during processing of the visual stimuli. Granger causality analysis revealed that the nucleus accumbens was communicating with the neocortex primarily in the theta-band, while the cortex was communicating the nucleus accumbens in the alpha-band. These data are consistent with a model, in which theta- and alpha-band oscillations serve dissociable roles: Prior to stimulus processing, the cortex might suppress ongoing processing in the nucleus accumbens by modulating alpha-band activity. Subsequently, upon stimulus presentation, theta oscillations might facilitate the active exchange of stimulus information from the nucleus accumbens to the cortex.

Characterization of beta-phenylethylamine-induced monoamine release in rat nucleus accumbens: a microdialysis study.

PubMed

Nakamura, M; Ishii, A; Nakahara, D

1998-05-22

In vivo microdialysis was used to investigate the effect of beta-phenylethylamine on extracellular levels of monoamines and their metabolites in the nucleus accumbens of conscious rats. At all doses tested (1, 10 and 100 microM), infusion of beta-phenylethylamine through the microdialysis probe significantly increased extracellular levels of dopamine in the nucleus accumbens. These increases were dose-related. The increase in dopamine levels induced by 100 microM beta-phenylethylamine was not affected by co-perfusion of 4 microM tetrodotoxin. The ability of 100 microM beta-phenylethylamine to increase the extracellular level of dopamine was comparable to that of the same dose of methamphetamine. On the other hand, beta-phenylethylamine had a much less potent enhancing effect on 5-hydroxytryptamine (5-HT) than dopamine levels. Only the highest dose (100 microM) caused a statistically significant effect on 5-HT levels. Over the dose range tested (1, 10 and 100 microM), beta-phenylethylamine had no effect on extracellular metabolite levels of dopamine and 5-HT. The results suggest that beta-phenylethylamine increases the efflux of monoamines, preferentially dopamine, without affecting monoamine metabolism, in the nucleus accumbens.

The response of a scintillation counter below an emulsion chamber to heavy nucleus interactions in the chamber

NASA Technical Reports Server (NTRS)

Burnett, T. H.; Dake, S.; Derrickson, J. H.; Fountain, W. F.; Fuki, M.; Gregory, J. C.; Hayashi, T.; Hayashi, T.; Holynski, R.; Iwai, J.;

Outbursts of H2O in Comet P/Halley

NASA Astrophysics Data System (ADS)

Larson, H. P.; Hu, H.-Y.; Mumma, M. J.; Weaver, H. A.

1990-07-01

Comet Halley gas-production monitoring efforts in March 1986 with the NASA Kuiper Airborne Observatory's Fourier transform spectrometer have indicated rapid temporal variations in H2O emissions; a continuous record of an H2O outburst was thus obtained. The event, in which H2O brightness increased by a factor of 2.2 in less than 10 min, is ascribable to an energetic process in the nucleus whose character may have been that of amorphous H2O ice crystallization, chemical explosion, thermal stress, or a compressed gas pocket. The timing and energy of the event appear to require an internal energy source; amorphous ice crystallization is held to be most consistent with compositional and thermal models of cometary nuclei as well as the observations.

Constraining the equation of state with identified particle spectra

NASA Astrophysics Data System (ADS)

Monnai, Akihiko; Ollitrault, Jean-Yves

2017-10-01

We show that in a central nucleus-nucleus collision, the variation of the mean transverse mass with the multiplicity is determined, up to a rescaling, by the variation of the energy over entropy ratio as a function of the entropy density, thus providing a direct link between experimental data and the equation of state. Each colliding energy thus probes the equation of state at an effective entropy density, whose approximate value is 19 fm-3 for Au+Au collisions at 200 GeV and 41 fm-3 for Pb+Pb collisions at 2.76 TeV, corresponding to temperatures of 227 and 279 MeV if the equation of state is taken from lattice calculations. The relative change of the mean transverse mass as a function of the colliding energy gives a direct measure of the pressure over energy density ratio P /ɛ , at the corresponding effective density. Using Relativistic Heavy Ion Collider (RHIC) and Large Hadron Collider (LHC) data, we obtain P /ɛ =0.21 ±0.10 , in agreement with the lattice value P /ɛ =0.23 in the corresponding temperature range. Measurements over a wide range of colliding energies using a single detector with good particle identification would help reduce the error.

Event-by-event pseudo-rapidity fluctuations in high energy nucleus-nucleus interactions

NASA Astrophysics Data System (ADS)

Bhattacharyya, Swarnapratim; Haiduc, Maria; Neagu, Alina Tania; Firu, Elena

2013-10-01

A detailed study of event-by-event pseudo-rapidity fluctuations in relativistic heavy-ion collisions in terms of the Φ measure and its multiplicity and target dependence has been carried out for heavy (AgBr) and light (CNO) groups of targets present in the nuclear emulsion using O16 (at an incident momentum of 4.5 A GeV/c), Ne22 (at an incident momentum of 4.1 A GeV/c), Si28 (at an incident momentum of 4.5 A GeV/c) and S32 (at an incident momentum of 4.5 A GeV/c) projectiles. For all the interactions, the total ensemble of events has been divided into three overlapping multiplicity classes depending on the number of shower particles. For all the interactions and for each multiplicity class, the Φ values are found to be greater than zero indicating the presence of strong correlation in the multiparticle production at Dubna energy. The measured Φ values are found to decrease with the increase of average multiplicity for all the interactions. The Φ values for the AgBr target are found to be greater than that for the CNO target for all the projectiles. This observation indicates the presence of stronger correlation for heavier projectiles. The experimental results have been compared with the modified FRITIOF model. It has been seen that the modified FRITIOF model cannot reproduce the experimental results.

Loss of polyubiquitin gene Ubb leads to metabolic and sleep abnormalities in mice

PubMed Central

Ryu, K.-Y.; Fujiki, N.; Kazantzis, M.; Garza, J. C.; Bouley, D. M.; Stahl, A.; Lu, X.-Y.; Nishino, S.; Kopito, R. R.

2010-01-01

Aims Ubiquitin performs essential roles in a myriad of signalling pathways required for cellular function and survival. Recently, we reported that disruption of the stress-inducible ubiquitin-encoding gene Ubb reduces ubiquitin content in the hypothalamus and leads to adult-onset obesity coupled with a loss of arcuate nucleus neurones and disrupted energy homeostasis in mice. Neuropeptides expressed in the hypothalamus control both metabolic and sleep behaviours. In order to demonstrate that the loss of Ubb results in broad hypothalamic abnormalities, we attempted to determine whether metabolic and sleep behaviours were altered in Ubb knockout mice. Methods Metabolic rate and energy expenditure were measured in a metabolic chamber, and sleep stage was monitored via electroencephalographic/electromyographic recording. The presence of neurodegeneration and increased reactive gliosis in the hypothalamus were also evaluated. Results We found that Ubb disruption leads to early-onset reduced activity and metabolic rate. Additionally, we have demonstrated that sleep behaviour is altered and sleep homeostasis is disrupted in Ubb knockout mice. These early metabolic and sleep abnormalities are accompanied by persistent reactive gliosis and the loss of arcuate nucleus neurones, but are independent of neurodegeneration in the lateral hypothalamus. Conclusions Ubb knockout mice exhibit phenotypes consistent with hypothalamic dysfunction. Our data also indicate that Ubb is essential for the maintenance of the ubiquitin levels required for proper regulation of metabolic and sleep behaviours in mice. PMID:20002312

Hypothyroidism Compromises Hypothalamic Leptin Signaling in Mice

PubMed Central

Groba, Claudia; Mayerl, Steffen; van Mullem, Alies A.; Visser, Theo J.; Darras, Veerle M.; Habenicht, Andreas J.

2013-01-01

The impact of thyroid hormone (TH) on metabolism and energy expenditure is well established, but the role of TH in regulating nutritional sensing, particularly in the central nervous system, is only poorly defined. Here, we studied the consequences of hypothyroidism on leptin production as well as leptin sensing in congenital hypothyroid TRH receptor 1 knockout (Trhr1 ko) mice and euthyroid control animals. Hypothyroid mice exhibited decreased circulating leptin levels due to a decrease in fat mass and reduced leptin expression in white adipose tissue. In neurons of the hypothalamic arcuate nucleus, hypothyroid mice showed increased leptin receptor Ob-R expression and decreased suppressor of cytokine signaling 3 transcript levels. In order to monitor putative changes in central leptin sensing, we generated hypothyroid and leptin-deficient animals by crossing hypothyroid Trhr1 ko mice with the leptin-deficient ob/ob mice. Hypothyroid Trhr1/ob double knockout mice showed a blunted response to leptin treatment with respect to body weight and food intake and exhibited a decreased activation of phospho-signal transducer and activator of transcription 3 as well as a up-regulation of suppressor of cytokine signaling 3 upon leptin treatment, particularly in the arcuate nucleus. These data indicate alterations in the intracellular processing of the leptin signal under hypothyroid conditions and thereby unravel a novel mode of action by which TH affects energy metabolism. PMID:23518925

Hypothalamic Vitamin D Improves Glucose Homeostasis and Reduces Weight.

PubMed

Sisley, Stephanie R; Arble, Deanna M; Chambers, Adam P; Gutierrez-Aguilar, Ruth; He, Yanlin; Xu, Yong; Gardner, David; Moore, David D; Seeley, Randy J; Sandoval, Darleen A

2016-09-01

Despite clear associations between vitamin D deficiency and obesity and/or type 2 diabetes, a causal relationship is not established. Vitamin D receptors (VDRs) are found within multiple tissues, including the brain. Given the importance of the brain in controlling both glucose levels and body weight, we hypothesized that activation of central VDR links vitamin D to the regulation of glucose and energy homeostasis. Indeed, we found that small doses of active vitamin D, 1α,25-dihydroxyvitamin D3 (1,25D3) (calcitriol), into the third ventricle of the brain improved glucose tolerance and markedly increased hepatic insulin sensitivity, an effect that is dependent upon VDR within the paraventricular nucleus of the hypothalamus. In addition, chronic central administration of 1,25D3 dramatically decreased body weight by lowering food intake in obese rodents. Our data indicate that 1,25D3-mediated changes in food intake occur through action within the arcuate nucleus. We found that VDR colocalized with and activated key appetite-regulating neurons in the arcuate, namely proopiomelanocortin neurons. Together, these findings define a novel pathway for vitamin D regulation of metabolism with unique and divergent roles for central nervous system VDR signaling. Specifically, our data suggest that vitamin D regulates glucose homeostasis via the paraventricular nuclei and energy homeostasis via the arcuate nuclei. © 2016 by the American Diabetes Association.

Projected Shell Model Description of Positive Parity Band of 130Pr Nucleus

NASA Astrophysics Data System (ADS)

Singh, Suram; Kumar, Amit; Singh, Dhanvir; Sharma, Chetan; Bharti, Arun; Bhat, G. H.; Sheikh, J. A.

2018-02-01

Theoretical investigation of positive parity yrast band of odd-odd 130Pr nucleus is performed by applying the projected shell model. The present study is undertaken to investigate and verify the very recently observed side band in 130Pr theoretically in terms of quasi-particle (qp) configuration. From the analysis of band diagram, the yrast as well as side band are found to arise from two-qp configuration πh 11/2 ⊗ νh 11/2. The present calculations are viewed to have qualitatively reproduced the known experimental data for yrast states, transition energies, and B( M1) / B( E2) ratios of this nucleus. The recently observed positive parity side band is also reproduced by the present calculations. The energy states of the side band are predicted up to spin 25+, which is far above the known experimental spin of 18+ and this could serve as a motivational factor for future experiments. In addition, the reduced transition probability B( E2) for interband transitions has also been calculated for the first time in projected shell model, which would serve as an encouragement for other research groups in the future.

K-mixing in the doubly mid-shell nuclide 170Dy and the role of vibrational degeneracy

NASA Astrophysics Data System (ADS)

Söderström, P.-A.; Walker, P. M.; Wu, J.; Liu, H. L.; Regan, P. H.; Watanabe, H.; Doornenbal, P.; Korkulu, Z.; Lee, P.; Liu, J. J.; Lorusso, G.; Nishimura, S.; Phong, V. H.; Sumikama, T.; Xu, F. R.; Yagi, A.; Zhang, G. X.; Ahn, D. S.; Alharbi, T.; Baba, H.; Browne, F.; Bruce, A. M.; Carroll, R. J.; Chae, K. Y.; Dombradi, Zs.; Estrade, A.; Fukuda, N.; Griffin, C. J.; Ideguchi, E.; Inabe, N.; Isobe, T.; Kanaoka, H.; Kanaya, S.; Kojouharov, I.; Kondev, F. G.; Kubo, T.; Kubono, S.; Kurz, N.; Kuti, I.; Lalkovski, S.; Lane, G. J.; Lee, E. J.; Lee, C. S.; Lotay, G.; Moon, C.-B.; Nishizuka, I.; Niţă, C. R.; Odahara, A.; Patel, Z.; Podolyák, Zs.; Roberts, O. J.; Sakurai, H.; Schaffner, H.; Shand, C. M.; Suzuki, H.; Takeda, H.; Terashima, S.; Vajta, Zs.; Valiente-Dòbon, J. J.; Xu, Z. Y.

2016-11-01

A detailed study of the structure of the doubly mid-shell nucleus 104 1 66 170 Dy has been carried out, following isomeric and β decay. We have measured the yrast band up to the spin-parity Jπ =6+ state, the K = 2γ-vibration band up to the 5+ state, a low-lying negative-parity band based on a 2- state that could be a candidate for the lowest energy octupole vibration state within this nucleus, and a candidate for the Kπ =6+ two quasi-particle isomer. This state was determined to have an excitation energy of 1643.91(23) keV and a half life of 0.99(4) μs, with a reduced hindrance for its decay to the ground-state band an order of magnitude lower than predicted by NpNn systematics. This is interpreted as being due to γ-vibrational mixing from a near degeneracy of the isomer and the 6+ state of the γ band. Furthermore, the parent nucleus 170Tb has been determined to have a half-life of 0.91 (+18-13) s with a possible spin-parity of 2-.

NASA Radiation Track Image GUI for Assessing Space Radiation Biological Effects

NASA Technical Reports Server (NTRS)

Ponomarev, Artem L.; Cucinotta, Francis A.

2006-01-01

The high-charge high-energy (HZE) ion components of the galactic cosmic rays when compared to terrestrial forms of radiations present unique challenges to biological systems. In this paper we present a deoxyribonucleic acid (DNA) breakage model to visualize and analyze the impact of chromatin domains and DNA loops on clustering of DNA damage from X rays, protons, and HZE ions. Our model of DNA breakage is based on a stochastic process of DNA double-strand break (DSB) formulation that includes the amorphous model of the radiation track and a polymer model of DNA packed in the cell nucleus. Our model is a Monte-Carlo simulation based on a randomly located DSB cluster formulation that accomodates both high- and low-linear energy transfer radiations. We demonstrate that HZE ions have a strong impact on DSB clustering, both along the chromosome length and in the nucleus volume. The effects of chromosomal domains and DNA loops on the DSB fragment-size distribution and the spatial distribution of DSB in the nucleus were studied. We compare our model predictions with the spatial distribution of DSB obtained from experiments. The implications of our model predictions for radiation protection are discussed.

Desipramine and citalopram attenuate pretest swim-induced increases in prodynorphin immunoreactivity in the dorsal bed nucleus of the stria terminalis and the lateral division of the central nucleus of the amygdala in the forced swimming test.

PubMed

Chung, Sung; Kim, Hee Jeong; Kim, Hyun Ju; Choi, Sun Hye; Cho, Jin Hee; Cho, Yun Ha; Kim, Dong-Hoon; Shin, Kyung Ho

2014-10-01

Dynorphin in the nucleus accumbens shell plays an important role in antidepressant-like effect in the forced swimming test (FST), but it is unclear whether desipramine and citalopram treatments alter prodynorphin levels in other brain areas. To explore this possibility, we injected mice with desipramine and citalopram 0.5, 19, and 23 h after a 15-min pretest swim and observed changes in prodynorphin expression before the test swim, which was conducted 24 h after the pretest swim. The pretest swim increased prodynorphin immunoreactivity in the dorsal bed nucleus of the stria terminalis (dBNST) and lateral division of the central nucleus of the amygdala (CeL). This increase in prodynorphin immunoreactivity in the dBNST and CeL was blocked by desipramine and citalopram treatments. Similar changes in prodynorphin mRNA levels were observed in the dBNST and CeL, but these changes did not reach significance. To understand the underlying mechanism, we assessed changes in phosphorylated CREB at Ser(133) (pCREB) immunoreactivity in the dBNST and central nucleus of the amygdala (CeA). Treatment with citalopram but not desipramine after the pretest swim significantly increased pCREB immunoreactivity only in the dBNST. These results suggest that regulation of prodynorphin in the dBNST and CeL before the test swim may be involved in the antidepressant-like effect of desipramine and citalopram in the FST and suggest that changes in pCREB immunoreactivity in these areas may not play an important role in the regulation of prodynorphin in the dBNST and CeA. Copyright © 2014 Elsevier Ltd. All rights reserved.

High-resolution study of Gamow-Teller excitations in the 42Ca(3He,t )42Sc reaction and the observation of a "low-energy super-Gamow-Teller state"

NASA Astrophysics Data System (ADS)

Fujita, Y.; Fujita, H.; Adachi, T.; Susoy, G.; Algora, A.; Bai, C. L.; Colò, G.; Csatlós, M.; Deaven, J. M.; Estevez-Aguado, E.; Guess, C. J.; Gulyás, J.; Hatanaka, K.; Hirota, K.; Honma, M.; Ishikawa, D.; Krasznahorkay, A.; Matsubara, H.; Meharchand, R.; Molina, F.; Nakada, H.; Okamura, H.; Ong, H. J.; Otsuka, T.; Perdikakis, G.; Rubio, B.; Sagawa, H.; Sarriguren, P.; Scholl, C.; Shimbara, Y.; Stephenson, E. J.; Suzuki, T.; Tamii, A.; Thies, J. H.; Yoshida, K.; Zegers, R. G. T.; Zenihiro, J.

2015-06-01

To study the Gamow-Teller (GT) transitions from the Tz=+1 nucleus 42Ca to the Tz=0 nucleus 42Sc, where Tz is the z component of isospin T , we performed a (p ,n )-type (3He,t ) charge-exchange reaction at 140 MeV/nucleon and scattering angles around 0∘. With an energy resolution of 29 keV, states excited by GT transitions (GT states) could be studied accurately. The reduced GT transition strengths B (GT) were derived up to the excitation energy of 13 MeV, assuming the proportionality between the cross sections at 0∘ and B (GT) values. The main part of the observed GT transition strength is concentrated in the lowest 0.611-MeV, Jπ=1+ GT state. All the other states at higher energies are weakly excited. Shell-model calculations could reproduce the gross feature of the experimental B (GT) distribution, and random-phase-approximation calculations including an attractive isoscalar interaction showed that the 0.611-MeV state has a collective nature. It was found that this state has all of the properties of a "low-energy super-Gamow-Teller state." It is expected that low-lying Jπ=1+ GT states have T =0 in the Tz=0 nucleus 42Sc. However, T =1 states are situated in a higher energy region. Assuming an isospin-analogous structure in A =42 isobars, analogous T =1 , 1+ states are also expected in 42Ca. Comparing the (3He 42,tCa) 42Sc and 42Ca(p ,p') spectra measured at 0∘, candidates for T =1 GT states could be found in the 10 -12 -MeV region of 42Sc. They were all weakly excited. The mass dependence of the GT strength distributions in Sc isotopes is also discussed.

Increase in cocaine- and amphetamine-regulated transcript (CART) in specific areas of the mouse brain by acute caffeine administration.

PubMed

Cho, Jin Hee; Cho, Yun Ha; Kim, Hyo Young; Cha, Seung Ha; Ryu, Hyun; Jang, Wooyoung; Shin, Kyung Ho

2015-04-01

Caffeine produces a variety of behavioral effects including increased alertness, reduced food intake, anxiogenic effects, and dependence upon repeated exposure. Although many of the effects of caffeine are mediated by its ability to block adenosine receptors, it is possible that other neural substrates, such as cocaine- and amphetamine-regulated transcript (CART), may be involved in the effects of caffeine. Indeed, a recent study demonstrated that repeated caffeine administration increases CART in the mouse striatum. However, it is not clear whether acute caffeine administration alters CART in other areas of the brain. To explore this possibility, we investigated the dose- and time-dependent changes in CART immunoreactivity (CART-IR) after a single dose of caffeine in mice. We found that a high dose of caffeine (100 mg/kg) significantly increased CART-IR 2 h after administration in the nucleus accumbens shell (AcbSh), dorsal bed nucleus of the stria terminalis (dBNST), central nucleus of the amygdala (CeA), paraventricular hypothalamic nucleus (PVN), arcuate hypothalamic nucleus (Arc), and locus coeruleus (LC), and returned to control levels after 8 h. But this increase was not observed in other brain areas. In addition, caffeine administration at doses of 25 and 50 mg/kg appears to produce dose-dependent increases in CART-IR in these brain areas; however, the magnitude of increase in CART-IR observed at a dose of 50 mg/kg was similar or greater than that observed at a dose of 100 mg/kg. This result suggests that CART-IR in AcbSh, dBNST, CeA, PVN, Arc, and LC is selectively affected by caffeine administration. Copyright © 2015 Elsevier Ltd. All rights reserved.

Pedunculopontine nucleus electric stimulation alleviates akinesia independently of dopaminergic mechanisms.

PubMed

Jenkinson, Ned; Nandi, Dipankar; Oram, Rebecca; Stein, John F; Aziz, Tipu Z

2006-04-24

The symptom of Parkinson's disease that is most disabling and difficult to treat is akinesia. We have previously shown that low-frequency stimulation of the pedunculopontine nucleus can alleviate such akinesia in a macaque rendered Parkinsonian using 1-methyl 4-phenyl 1,2,3,6-tetrahydropyridine. Here, we have extended that study to show that adding stimulation of the pedunculopontine nucleus to levodopa treatment in this Parkinsonian monkey increased its motor activity significantly more than levodopa alone. This additivity suggests that pedunculopontine nucleus stimulation may improve movement by acting at a site downstream from where levodopa therapy affects the basal ganglia.

Interactions between the nucleus accumbens and auditory cortices predict music reward value.

PubMed

Salimpoor, Valorie N; van den Bosch, Iris; Kovacevic, Natasa; McIntosh, Anthony Randal; Dagher, Alain; Zatorre, Robert J

2013-04-12

We used functional magnetic resonance imaging to investigate neural processes when music gains reward value the first time it is heard. The degree of activity in the mesolimbic striatal regions, especially the nucleus accumbens, during music listening was the best predictor of the amount listeners were willing to spend on previously unheard music in an auction paradigm. Importantly, the auditory cortices, amygdala, and ventromedial prefrontal regions showed increased activity during listening conditions requiring valuation, but did not predict reward value, which was instead predicted by increasing functional connectivity of these regions with the nucleus accumbens as the reward value increased. Thus, aesthetic rewards arise from the interaction between mesolimbic reward circuitry and cortical networks involved in perceptual analysis and valuation.

Direct Observation of Nanoparticle-Cancer Cell Nucleus Interactions

PubMed Central

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

2012-01-01

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

CGRP Antagonist Infused into the Bed Nucleus of the Stria Terminalis Impairs the Acquisition and Expression of Context but Not Discretely Cued Fear

ERIC Educational Resources Information Center

Sink, Kelly S.; Davis, Michael; Walker, David L.

2013-01-01

Calcitonin gene-related peptide (CGRP) infusions into the bed nucleus of the stria terminalis (BNST) evoke increases in startle amplitude and increases in anxiety-like behavior in the plus maze. Conversely, intra-BNST infusions of the CGRP antagonist CGRP[subscript 8-37] block unconditioned startle increases produced by fox odor. Here we evaluate…

Measurements of production cross sections of 10Be and 26Al by 120 GeV and 392 MeV proton bombardment of 89Y, 159Tb, and natCu targets

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sekimoto, S.; Okumura, S.; Yashima, H.

2015-08-12

The production cross sections of 10Be and 26Al were measured by accelerator mass spectrometry using 89Y, 159Tb, and natCu targets bombarded by protons with energies E p of 120 GeV and 392 MeV. The production cross sections obtained for 10Be and 26Al were compared with those previously reported using E p = 50 MeV–24 GeV and various targets. It was found that the production cross sections of 10Be monotonically increased with increasing target mass number when the proton energy was greater than a few GeV. On the other hand, it was also found that the production cross sections of 10Bemore » decreased as the target mass number increased from that of carbon to those near the mass numbers of nickel and zinc when the proton energy was below approximately 1 GeV. They also increased as the target mass number increased from near those of nickel and zinc to that of bismuth, in the same proton energy range. Similar results were observed in the production cross sections of 26Al, though the absolute values were quite different between 10Be and 26Al. As a result, the difference between these production cross sections may depend on the impact parameter (nuclear radius) and/or the target nucleus stiffness.« less

Immunosuppressive Yersinia Effector YopM Binds DEAD Box Helicase DDX3 to Control Ribosomal S6 Kinase in the Nucleus of Host Cells.

PubMed

Berneking, Laura; Schnapp, Marie; Rumm, Andreas; Trasak, Claudia; Ruckdeschel, Klaus; Alawi, Malik; Grundhoff, Adam; Kikhney, Alexey G; Koch-Nolte, Friedrich; Buck, Friedrich; Perbandt, Markus; Betzel, Christian; Svergun, Dmitri I; Hentschke, Moritz; Aepfelbacher, Martin

2016-06-01

Yersinia outer protein M (YopM) is a crucial immunosuppressive effector of the plaque agent Yersinia pestis and other pathogenic Yersinia species. YopM enters the nucleus of host cells but neither the mechanisms governing its nucleocytoplasmic shuttling nor its intranuclear activities are known. Here we identify the DEAD-box helicase 3 (DDX3) as a novel interaction partner of Y. enterocolitica YopM and present the three-dimensional structure of a YopM:DDX3 complex. Knockdown of DDX3 or inhibition of the exportin chromosomal maintenance 1 (CRM1) increased the nuclear level of YopM suggesting that YopM exploits DDX3 to exit the nucleus via the CRM1 export pathway. Increased nuclear YopM levels caused enhanced phosphorylation of Ribosomal S6 Kinase 1 (RSK1) in the nucleus. In Y. enterocolitica infected primary human macrophages YopM increased the level of Interleukin-10 (IL-10) mRNA and this effect required interaction of YopM with RSK and was enhanced by blocking YopM's nuclear export. We propose that the DDX3/CRM1 mediated nucleocytoplasmic shuttling of YopM determines the extent of phosphorylation of RSK in the nucleus to control transcription of immunosuppressive cytokines.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kino, Motoki; Ito, Hirotaka; Kawakatu, Nozomu

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

AGN ACTIVITY AND IGM HEATING IN THE FOSSIL CLUSTER RX J1416.4+2315

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miraghaei, H.; Khosroshahi, H. G.; Abbassi, S.

2015-12-15

We study active galactic nucleus (AGN) activity in the fossil galaxy cluster RX J1416.4+2315. Radio observations were carried out using the Giant Metrewave Radio Telescope at two frequencies, 1420 and 610 MHz. A weak radio lobe that extends from the central nucleus is detected in the 610 MHz map. Assuming the radio lobe originated from the central AGN, we show that the energy injection into the intergalactic medium is only sufficient to heat up the central 50 kpc within the cluster core, while the cooling radius is larger (∼130 kpc). In the hardness ratio map, three low energy cavities havemore » been identified. No radio emission is detected for these regions. We evaluated the power required to inflate the cavities and showed that the total energy budget is sufficient to offset the radiative cooling. We showed that the initial conditions would change the results remarkably. Furthermore, the efficiency of the Bondi accretion in powering the AGN has been estimated.« less

Analysis of the energy of the first four excited states of the ground-state rotational bands of the even-even nuclei from 6C8 to 56Ba90 with the model of a single cluster of nucleons revolving about a sphere.

PubMed Central

Pauling, L

1991-01-01

The results of the analysis of the first four energy levels of the ground-state rotational bands of even-even nuclei from 6C8 to 56Ba90 on the basis of the revolving-cluster model are reported. Values of the nucleon number of the revolving cluster are assigned on the basis in part of the shell model and in part of the expectation that the corresponding values of the radius of revolution would change only slightly from one energy level to an adjacent level or from one nucleus to an adjacent nucleus. The values of the radius of revolution are found to change gradually from about 5 to 6 fm for the lighter nuclei to 7 to 8 fm for the heavier nuclei in the sequence studied. PMID:11607232

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kish, Edward R.; Desai, Tushar V.; Greer, Douglas R.

The authors have examined the nucleation of diindenoperylene (DIP) on SiO{sub 2} employing primarily atomic force microscopy and focusing on the effect of incident kinetic energy employing both thermal and supersonic sources. For all incident kinetic energies examined (E{sub i} = 0.09–11.3 eV), the nucleation of DIP is homogeneous and the dependence of the maximum island density on the growth rate is described by a power law. A critical nucleus of approximately two molecules is implicated by our data. A re-examination of the nucleation of pentacene on SiO{sub 2} gives the same major result that the maximum island density is determined by themore » growth rate, and it is independent of the incident kinetic energy. These observations are readily understood by factoring in the size of the critical nucleus in each case, and the island density, which indicates that diffusive transport of molecules to the growing islands dominate the dynamics of growth in the submonolayer regime.« less

Hadron calorimeter (PSD) with new photo-detectors (MPPC) in NA61 experiment at CERN

NASA Astrophysics Data System (ADS)

Golubeva, M.; Guber, F.; Ivashkin, A.; Izvestnyy, A.; Kurepin, A.; Morozov, S.; Petukhov, O.; Selyuzhenkov, I.; Svintsov, I.; Taranenko, A.

2017-01-01

The Projectile Spectator Detector (PSD) is a segmented hadron calorimeter used in NA61 experiment (CERN) to determine a collision centrality as well as an event plane orientation in nucleus-nucleus collisions. The main goal of the experiment includes studying the onset of de-confinement and searching for the critical point of strongly interacting matter. It is of crucial importance to have a precise characterization of the event class with the PSD for the analysis of event-by-event observables. The PSD has been already used for centrality selection on trigger level in measurements of Be+Be and Ar+Sc reactions at beam energies 13 - 158 AGeV and Pb+Pb reaction at beam energy 30 AGeV. In 2016, the central modules of PSD have been equipped with new Hamamatsu MPPC silicon photo-detectors in order to extend dynamic range for studying Pb+Pb reaction at the full energy range 13 - 158 AGeV. Results of the PSD response on proton and lead beams are presented.

Kinetic theory of heterogeneous nucleation; effect of nonuniform density in the nuclei.

PubMed

Berim, Gersh O; Ruckenstein, Eli

2011-03-01

The heterogeneous nucleation of a liquid from a vapor in contact with a planar solid surface or a solid surface with cavities is examined on the basis of the kinetic theory of nucleation developed by Nowakowski and Ruckenstein [J. Phys. Chem. 96 (1992) 2313] which is extended to nonuniform fluid density distribution (FDD) in the nucleus. The latter is determined under the assumption that at each moment the FDD in the nucleus is provided by the density functional theory (DFT) for a nanodrop. As a result of this assumption, the theory does not require to consider that the contact angle which the nucleus makes with the solid surface and the density of the nucleus are independent parameters since they are provided by the DFT. For all considered cases, the nucleation rate is higher in the cavities than on a planar surface and increases with increasing strength of the fluid-solid interactions and decreasing cavity radius. The difference is small at high supersaturations (small critical nuclei), but becomes larger at low supersaturations when the critical nucleus has a size comparable with the size of the cavity. The nonuniformity of the FDD in the nucleus decreases the nucleation rate when compared to the uniform FDD. Copyright © 2010 Elsevier Inc. All rights reserved.

Featured Article: Effect of copper on nuclear translocation of copper chaperone for superoxide dismutase-1

PubMed Central

Wang, Lin; Ge, Yan

2016-01-01

Copper chaperone for superoxide dismutase-1 (CCS-1), facilitating copper insertion into superoxide dismutase 1 (SOD-1), is present in the nucleus. However, it is unknown how CCS-1 is translocated to the nucleus. The present study was undertaken to determine the effect of copper on nuclear translocation of CCS-1. Human umbilical vein endothelial cells (HUVECs) were subjected to hypoxia, causing an increase in both copper and CCS-1 in the nucleus. Treatment with tetraethylenepentamine (TEPA) not only decreased the total cellular concentration and the nuclear translocation of copper, but also completely suppressed the entry of CCS-1 to the nucleus. On the other hand, siRNA targeting CCS-1 neither inhibited the increase in total concentrations nor blocked the nuclear translocation of copper. This study thus demonstrates that under hypoxia condition, both copper and CCS-1 are transported to the nucleus. The nuclear translocation of CCS-1 is copper dependent, but the nuclear translocation of copper could take place alternatively in a CCS-1-independent pathway. PMID:27190267

In vitro and in silico investigations of disc nucleus replacement

PubMed Central

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

2012-01-01

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

Nineteenth International Cosmic Ray Conference. Conference Papers: Invited Rapporteur, Highlight, Miscellaneous, Volume 9

NASA Technical Reports Server (NTRS)

Jones, F. C. (Compiler)

1986-01-01

Invited talks, rapporteur talks, and highlight talks are included. Topics of the invited and highlight talks include astrophysical jets, gamma-ray line astronomy, cosmic rays and gamma rays in astrophysics, the early universe, elementary particle physics, solar flares and acceleration of energetic particles, cosmogenic nuclei, extragalactic astronomy, composition of solar flare particles, very high energy gamma ray sources, gamma-ray bursts, shock acceleration in the solar wind, cosmic rays in deep underground detectors, spectrum of cosmic rays at 10 to the 19th power eV, and nucleus-nucleus interactions.

Evidence of scaling of void probability in nucleus-nucleus interactions at few GeV energy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ghosh, Dipak; Biswas, Biswanath; Deb, Argha

1997-11-01

The rapidity gap probability in the {sup 24}Mg-AgBr interaction at 4.5GeV/c/nucleon has been studied in detail. The data reveal scaling behavior of the void probability in the central rapidity domain which confirms the validity of the linked-pair approximation for the N-particle cumulant correlation functions. This scaling behavior appears to be similar to the void probability in the Perseus-Pisces supercluster region of galaxies. {copyright} {ital 1997} {ital The American Physical Society}

Target correlation effects on neutron-nucleus total, absorption, and abrasion cross sections

NASA Technical Reports Server (NTRS)

Cucinotta, Francis A.; Townsend, Lawrence W.; Wilson, John W.

1991-01-01

Second order optical model solutions to the elastic scattering amplitude were used to evaluate total, absorption, and abrasion cross sections for neutron nucleus scattering. Improved agreement with experimental data for total and absorption cross sections is found when compared with first order (coherent approximation) solutions, especially below several hundred MeV. At higher energies, the first and second order solutions are similar. There are also large differences in abrasion cross section calculations; these differences indicate a crucial role for cluster knockout in the abrasion step.

Ground-state proton decay of 69Br and implications for the rp -process 68Se waiting-point

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rogers, Andrew M; Shapira, Dan; Lynch, William

2011-01-01

The first direct measurement of the proton separation energy, S p , for the proton-unbound nucleus 69Br is reported. Of interest is the exponential dependence of the 2 p-capture rate on S p which can bypass the 68Se waiting-point in the astrophysical rp process. An analysis of the observed proton decay spectrum is given in terms of the 69Se mirror nucleus and the influence of S p is explored within the context of a single-zone X-ray burst model.

Investigation of the heavy nuclei fission with anomalously high values of the fission fragments total kinetic energy

NASA Astrophysics Data System (ADS)

Khryachkov, Vitaly; Goverdovskii, Andrei; Ketlerov, Vladimir; Mitrofanov, Vecheslav; Sergachev, Alexei

2018-03-01

Binary fission of 232Th and 238U induced by fast neutrons were under intent investigation in the IPPE during recent years. These measurements were performed with a twin ionization chamber with Frisch grids. Signals from the detector were digitized for further processing with a specially developed software. It results in information of kinetic energies, masses, directions and Bragg curves of registered fission fragments. Total statistics of a few million fission events were collected during each experiment. It was discovered that for several combinations of fission fragment masses their total kinetic energy was very close to total free energy of the fissioning system. The probability of such fission events for the fast neutron induced fission was found to be much higher than for spontaneous fission of 252Cf and thermal neutron induced fission of 235U. For experiments with 238U target the energy of incident neutrons were 5 MeV and 6.5 MeV. Close analysis of dependence of fission fragment distribution on compound nucleus excitation energy gave us some explanation of the phenomenon. It could be a process in highly excited compound nucleus which leads the fissioning system from the scission point into the fusion valley with high probability.

Palmitic acid mediates hypothalamic insulin resistance by altering PKC-θ subcellular localization in rodents

PubMed Central

Benoit, Stephen C.; Kemp, Christopher J.; Elias, Carol F.; Abplanalp, William; Herman, James P.; Migrenne, Stephanie; Lefevre, Anne-Laure; Cruciani-Guglielmacci, Céline; Magnan, Christophe; Yu, Fang; Niswender, Kevin; Irani, Boman G.; Holland, William L.; Clegg, Deborah J.

2009-01-01

Insulin signaling can be modulated by several isoforms of PKC in peripheral tissues. Here, we assessed whether one specific isoform, PKC-θ, was expressed in critical CNS regions that regulate energy balance and whether it mediated the deleterious effects of diets high in fat, specifically palmitic acid, on hypothalamic insulin activity in rats and mice. Using a combination of in situ hybridization and immunohistochemistry, we found that PKC-θ was expressed in discrete neuronal populations of the arcuate nucleus, specifically the neuropeptide Y/agouti-related protein neurons and the dorsal medial nucleus in the hypothalamus. CNS exposure to palmitic acid via direct infusion or by oral gavage increased the localization of PKC-θ to cell membranes in the hypothalamus, which was associated with impaired hypothalamic insulin and leptin signaling. This finding was specific for palmitic acid, as the monounsaturated fatty acid, oleic acid, neither increased membrane localization of PKC-θ nor induced insulin resistance. Finally, arcuate-specific knockdown of PKC-θ attenuated diet-induced obesity and improved insulin signaling. These results suggest that many of the deleterious effects of high-fat diets, specifically those enriched with palmitic acid, are CNS mediated via PKC-θ activation, resulting in reduced insulin activity. PMID:19726875

Impacts of compression on crystallization behavior of freeze-dried amorphous sucrose.

PubMed

Imamura, Koreyoshi; Nomura, Mayo; Tanaka, Kazuhiro; Kataoka, Nobuhide; Oshitani, Jun; Imanaka, Hiroyuki; Nakanishi, Kazuhiro

2010-03-01

An amorphous matrix comprised of sugar molecules is used as excipient and stabilizing agent for labile ingredients in the pharmaceutical industry. The amorphous sugar matrix is often compressed into a tablet form to reduce the volume and improve handling. Herein, the effect of compression on the crystallization behavior of an amorphous sucrose matrix was investigated. Amorphous sucrose samples were prepared by freeze-drying and compressed under different conditions, followed by analyses by differential scanning calorimetry, isothermal crystallization tests, X-ray powder diffractometry, Fourier transform infrared spectroscopy (FTIR), and gas pycnometry. The compressed sample had a lower crystallization temperature and a shorter induction period for isothermal crystallization, indicating that compression facilitates the formation of the critical nucleus of a sucrose crystal. Based on FTIR and molecular dynamics simulation results, the conformational distortion of sucrose molecules due to the compression appears to contribute to the increase in the free energy of the system, which leads to the facilitation of critical nucleus formation. An isothermal crystallization test indicated an increase in the growth rate of sucrose crystals by the compression. This can be attributed to the transformation of the microstructure from porous to nonporous, as the result of compression. 2009 Wiley-Liss, Inc. and the American Pharmacists Association

Dynamic Amygdala Influences on the Fronto-Striatal Brain Mechanisms Involved in Self-Control of Impulsive Desires.

PubMed

Krämer, Bernd; Gruber, Oliver

2015-01-01

Human decisions are guided by a variety of motivational factors, such as immediate rewards, long-term goals, and emotions. We used functional magnetic resonance imaging to investigate the dynamic functional interactions between the amygdala, the nucleus accumbens, and the prefrontal cortex that underlie the influences of emotions, desires, and rationality on human decisions. We found that increased functional connectivity between the amygdala and the nucleus accumbens facilitated the approach of an immediate reward in the presence of emotional information. Further, increased functional interactions of the anteroventral prefrontal cortex with the amygdala and the nucleus accumbens were associated with rational decisions in dilemma situations. These findings support previous animal studies by demonstrating that emotional signals from the amygdala and goal-oriented information from prefrontal cortices interface in the nucleus accumbens to guide human decisions and reward-directed actions. © 2015 S. Karger AG, Basel.

Glucose Induces Slow-Wave Sleep by Exciting the Sleep-Promoting Neurons in the Ventrolateral Preoptic Nucleus: A New Link between Sleep and Metabolism.

PubMed

Varin, Christophe; Rancillac, Armelle; Geoffroy, Hélène; Arthaud, Sébastien; Fort, Patrice; Gallopin, Thierry

2015-07-08

Sleep-active neurons located in the ventrolateral preoptic nucleus (VLPO) play a crucial role in the induction and maintenance of slow-wave sleep (SWS). However, the cellular and molecular mechanisms responsible for their activation at sleep onset remain poorly understood. Here, we test the hypothesis that a rise in extracellular glucose concentration in the VLPO can promote sleep by increasing the activity of sleep-promoting VLPO neurons. We find that infusion of a glucose concentration into the VLPO of mice promotes SWS and increases the density of c-Fos-labeled neurons selectively in the VLPO. Moreover, we show in patch-clamp recordings from brain slices that VLPO neurons exhibiting properties of sleep-promoting neurons are selectively excited by glucose within physiological range. This glucose-induced excitation implies the catabolism of glucose, leading to a closure of ATP-sensitive potassium (KATP) channels. The extracellular glucose concentration monitors the gating of KATP channels of sleep-promoting neurons, highlighting that these neurons can adapt their excitability according to the extracellular energy status. Together, these results provide evidence that glucose may participate in the mechanisms of SWS promotion and/or consolidation. Although the brain circuitry underlying vigilance states is well described, the molecular mechanisms responsible for sleep onset remain largely unknown. Combining in vitro and in vivo experiments, we demonstrate that glucose likely contributes to sleep onset facilitation by increasing the excitability of sleep-promoting neurons in the ventrolateral preoptic nucleus (VLPO). We find here that these neurons integrate energetic signals such as ambient glucose directly to regulate vigilance states accordingly. Glucose-induced excitation of sleep-promoting VLPO neurons should therefore be involved in the drowsiness that one feels after a high-sugar meal. This novel mechanism regulating the activity of VLPO neurons reinforces the fundamental and intimate link between sleep and metabolism. Copyright © 2015 the authors 0270-6474/15/359900-12$15.00/0.

Measurement of key resonances for the Al 24 ( p , γ ) Si 25 reaction rate using in-beam γ -ray spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Longfellow, B.; Gade, A.; Brown, B. A.

Energy levels and branching ratios for the rp-process nucleus 25Si were determined from the reactions 9Be ( 26Si, 25Si) X and 9Be ( 25Al, 25Si) X using in-beam γ-ray spectroscopy with both high-efficiency and high-resolution detector arrays. Proton-unbound states at 3695(14) and 3802(11) keV were identified and assigned tentative spins and parities based on comparison to theory and the mirror nucleus. The 24Al (p, γ) 25Si reaction rate was calculated using the experimental states and states from charge-dependent USDA and USDB shell-model calculations with downward shifts of the 1s 1/2 proton orbital to account for the observed Thomas-Ehrman shift, leadingmore » to a factor of 10–100 increase in rate for the temperature region of 0.22 GK as compared to a previous calculation. These shifts may be applicable to neighboring nuclei, impacting the proton capture rates in this region of the chart.« less

Measurement of key resonances for the Al 24 ( p , γ ) Si 25 reaction rate using in-beam γ -ray spectroscopy

DOE PAGES

Longfellow, B.; Gade, A.; Brown, B. A.; ...

2018-05-04

Energy levels and branching ratios for the rp-process nucleus 25Si were determined from the reactions 9Be ( 26Si, 25Si) X and 9Be ( 25Al, 25Si) X using in-beam γ-ray spectroscopy with both high-efficiency and high-resolution detector arrays. Proton-unbound states at 3695(14) and 3802(11) keV were identified and assigned tentative spins and parities based on comparison to theory and the mirror nucleus. The 24Al (p, γ) 25Si reaction rate was calculated using the experimental states and states from charge-dependent USDA and USDB shell-model calculations with downward shifts of the 1s 1/2 proton orbital to account for the observed Thomas-Ehrman shift, leadingmore » to a factor of 10–100 increase in rate for the temperature region of 0.22 GK as compared to a previous calculation. These shifts may be applicable to neighboring nuclei, impacting the proton capture rates in this region of the chart.« less

Microscopic mechanism of nanocrystal formation from solution by cluster aggregation and coalescence

PubMed Central

Hassan, Sergio A.

2011-01-01

Solute-cluster aggregation and particle fusion have recently been suggested as alternative routes to the classical mechanism of nucleation from solution. The role of both processes in the crystallization of an aqueous electrolyte under controlled salt addition is here elucidated by molecular dynamics simulation. The time scale of the simulation allows direct observation of the entire crystallization pathway, from early events in the prenucleation stage to the formation of a nanocrystal in equilibrium with concentrated solution. The precursor originates in a small amorphous aggregate stabilized by hydration forces. The core of the nucleus becomes crystalline over time and grows by coalescence of the amorphous phase deposited at the surface. Imperfections of ion packing during coalescence promote growth of two conjoint crystallites. A parameter of order and calculated cohesive energies reflect the increasing crystalline order and stress relief at the grain boundary. Cluster aggregation plays a major role both in the formation of the nucleus and in the early stages of postnucleation growth. The mechanism identified shares common features with nucleation of solids from the melt and of liquid droplets from the vapor. PMID:21428633

Odd-Z Transactinide Compound Nucleus Reactions Including the Discovery of 260Bh

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nelson, Sarah L.

Several reactions producing odd-Z transactinide compound nuclei were studiedwith the 88-Inch Cyclotron and the Berkeley Gas-Filled Separator at the Lawrence Berkeley National Laboratory. The goal was to produce the same compound nucleus ator near the same excitation energy with similar values of angular momentum via differentnuclear reactions. In doing so, it can be determined if there is a preference in entrancechannel, because under these experimental conditions the survival portion of Swiatecki, Siwek-Wilcznska, and Wilczynski's"Fusion By Diffusion" model is nearly identical forthe two reactions. Additionally, because the same compound nucleus is produced, theexit channel is the same. Four compound nuclei were examined in this study: 258Db, 262Bh, 266Mt, and 272Rg. These nuclei were produced by using very similar heavy-ion induced-fusion reactions which differ only by one proton in the projectile or target nucleus (e.g.: 50Ti + 209Bi vs. 51V + 208Pb). Peak 1n exit channel cross sections were determined for each reaction in each pair, and three of the four pairs' cross sections were identical within statistical uncertainties. This indicates there is not an obvious preference of entrancechannel in these paired reactions. Charge equilibration immediately prior to fusionleading to a decreased fusion barrier is the likely cause of this phenomenon. In addition to this systematic study, the lightest isotope of element 107, bohrium, was discovered in the 209Bi( 52Cr,n) reaction. 260Bh was found to decay by emission of a 10.16 MeV alpha particle with a half-life of 35more » $$+19\\atop{-9}$$ ms. The cross section is 59 pb at an excitation energy of 15.0 MeV. The effect of the N = 152 shell is also seen in this isotope's alpha particle energy, the first evidence of such an effect in Bh. All reactions studied are also compared to model predictions by Swiatecki, Siwek-Wilcznska, and Wilczynski 's" Fusion By Diffusion " theory.« less

Atomic Energy Basics, Understanding the Atom Series.

ERIC Educational Resources Information Center

Atomic Energy Commission, Oak Ridge, TN. Div. of Technical Information.

This booklet is part of the "Understanding the Atom Series," though it is a later edition and not included in the original set of 51 booklets. A basic survey of the principles of nuclear energy and most important applications are provided. These major topics are examined: matter has molecules and atoms, the atom has electrons, the nucleus,…

Description of alpha-nucleus interaction cross sections for cosmic ray shielding studies

NASA Technical Reports Server (NTRS)

Cucinotta, Francis A.; Townsend, Lawrence W.; Wilson, John W.

1993-01-01

Nuclear interactions of high-energy alpha particles with target nuclei important for cosmic ray studies are discussed. Models for elastic, quasi-elastic, and breakup reactions are presented and compared with experimental data. Energy-dependent interaction cross sections and secondary spectra are presented based on theoretical models and the limited experimental data base.

A Macroscopic Analogue of the Nuclear Pairing Potential

ERIC Educational Resources Information Center

Dunlap, Richard A.

2013-01-01

A macroscopic system involving permanent magnets is used as an analogue to nucleons in a nucleus to illustrate the significance of the pairing interaction. This illustrates that the view of the total nuclear energy based only on the nucleon occupancy of the energy levels can yield erroneous results and it is only when the pairing interaction is…

Determination of the η‧-nucleus optical potential

NASA Astrophysics Data System (ADS)

Nanova, M.; Metag, V.; Paryev, E. Ya.; Bayadilov, D.; Bantes, B.; Beck, R.; Beloglazov, Y. A.; Böse, S.; Brinkmann, K.-T.; Challand, Th.; Crede, V.; Dahlke, T.; Dietz, F.; Drexler, P.; Eberhardt, H.; Elsner, D.; Ewald, R.; Fornet-Ponse, K.; Friedrich, S.; Frommberger, F.; Funke, Ch.; Gottschall, M.; Gridnev, A.; Grüner, M.; Gutz, E.; Hammann, Ch.; Hammann, D.; Hannappel, J.; Hartmann, J.; Hillert, W.; Hoffmeister, P.; Honisch, Ch.; Jaegle, I.; Kaiser, D.; Kalinowsky, H.; Kammer, S.; Keshelashvili, I.; Kleber, V.; Klein, F.; Klempt, E.; Krusche, B.; Lang, M.; Lopatin, I. V.; Maghrbi, Y.; Makonyi, K.; Müller, J.; Odenthal, T.; Piontek, D.; Schaepe, S.; Schmidt, Ch.; Schmieden, H.; Schmitz, R.; Seifen, T.; Thiel, A.; Thoma, U.; van Pee, H.; Walther, D.; Wendel, Ch.; Wiedner, U.; Wilson, A.; Winnebeck, A.; Zenke, F.

2013-12-01

The excitation function and momentum distribution of η‧ mesons have been measured in photon induced reactions on 12C in the energy range of 1250-2600 MeV. The experiment was performed with tagged photon beams from the ELSA electron accelerator using the Crystal Barrel and TAPS detectors. The data are compared to model calculations to extract information on the sign and magnitude of the real part of the η‧-nucleus potential. Within the model, the comparison indicates an attractive potential of -(37±10(stat)±10(syst)) MeV depth at normal nuclear matter density. Since the modulus of this depth is larger than the modulus of the imaginary part of the η‧-nucleus potential of -(10±2.5) MeV, determined by transparency ratio measurements, a search for resolved η‧-bound states appears promising.

Mapping color fluctuations in the photon in ultraperipheral heavy ion collisions at the Large Hadron Collider

DOE PAGES

Alvioli, M.; Frankfurt, L.; Guzey, V.; ...

2017-02-20

Here, we model effects of color fluctuations (CFs) in the light-cone photon wave function and for the first time make predictions for the distribution over the number of wounded nucleons ν in the inelastic photon–nucleus scattering. We show that CFs lead to a dramatic enhancement of this distribution at ν=1 and large ν>10. We also study the implications of different scales and CFs in the photon wave function on the total transverse energy ΣE T and other observables in inelastic γA scattering with different triggers. Our predictions can be tested in proton–nucleus and nucleus–nucleus ultraperipheral collisions at the LHC andmore » will help to map CFs, whose first indications have already been observed at the LHC.« less

Wobbling mode inf {sup 167}Ta.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hartley, D. J.; Janssens, R. V. F.; Riedinger, L. L.

2009-01-01

The collective wobbling mode, the strongest signature for the rotation of a triaxial nucleus, has previously been seen only in a few Lu isotopes in spite of extensive searches in nearby isotopes. A sequence of transitions in the N = 94 {sup 167}Ta nucleus exhibiting features similar to those attributed to the wobbling bands in the Lu nuclei has now been found. This band feeds into the {pi}/{sub 13/2} band at a relative energy similar to that seen in the established wobbling bands and its dynamic moment of inertia and alignment properties are nearly identical to the /{sub 13/2} structuremore » over a significant frequency range. Given these characteristics, it is likely that the wobbling mode has been observed for the first time in a nucleus other than Lu, making this collective motion a more general phenomenon.« less

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

DOE PAGES

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

2015-10-02

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

Monte Carlo based dosimetry for neutron capture therapy of brain tumors

NASA Astrophysics Data System (ADS)

Zaidi, Lilia; Belgaid, Mohamed; Khelifi, Rachid

2016-11-01

Boron Neutron Capture Therapy (BNCT) is a biologically targeted, radiation therapy for cancer which combines neutron irradiation with a tumor targeting agent labeled with a boron10 having a high thermal neutron capture cross section. The tumor area is subjected to the neutron irradiation. After a thermal neutron capture, the excited 11B nucleus fissions into an alpha particle and lithium recoil nucleus. The high Linear Energy Transfer (LET) emitted particles deposit their energy in a range of about 10μm, which is of the same order of cell diameter [1], at the same time other reactions due to neutron activation with body component are produced. In-phantom measurement of physical dose distribution is very important for BNCT planning validation. Determination of total absorbed dose requires complex calculations which were carried out using the Monte Carlo MCNP code [2].

Higher moments of multiplicity fluctuations in a hadron-resonance gas with exact conservation laws

NASA Astrophysics Data System (ADS)

Fu, Jing-Hua

2017-09-01

Higher moments of multiplicity fluctuations of hadrons produced in central nucleus-nucleus collisions are studied within the hadron-resonance gas model in the canonical ensemble. Exact conservation of three charges, baryon number, electric charge, and strangeness is enforced in the large volume limit. Moments up to the fourth order of various particles are calculated at CERN Super Proton Synchrotron, BNL Relativistic Heavy Ion Collider (RHIC), and CERN Large Hadron Collider energies. The asymptotic fluctuations within a simplified model with only one conserved charge in the canonical ensemble are discussed where simple analytical expressions for moments of multiplicity distributions can be obtained. Moments products of net-proton, net-kaon, and net-charge distributions in Au + Au collisions at RHIC energies are calculated. The pseudorapidity coverage dependence of net-charge fluctuation is discussed.

Uncertainties in modeling low-energy neutrino-induced reactions on iron-group nuclei

NASA Astrophysics Data System (ADS)

Paar, N.; Suzuki, T.; Honma, M.; Marketin, T.; Vretenar, D.

2011-10-01

Charged-current neutrino-nucleus cross sections for 54,56Fe and 58,60Ni are calculated and compared using frameworks based on relativistic and Skyrme energy-density functionals and on the shell model. The current theoretical uncertainties in modeling neutrino-nucleus cross sections are assessed in relation to the predicted Gamow-Teller transition strength and available data, to multipole decomposition of the cross sections, and to cross sections averaged over the Michel flux and Fermi-Dirac distribution. By employing different microscopic approaches and models, the decay-at-rest (DAR) neutrino-56Fe cross section and its theoretical uncertainty are estimated to be <σ>th=(258±57)×10-42cm2, in very good agreement with the experimental value <σ>exp=(256±108±43)×10-42cm2.

Measurements of the {sup 116}Cd(p,n) and {sup 116}Sn(n,p) reactions at 300 MeV for studying Gamow-Teller transition strengths in the intermediate nucleus of the {sup 116}Cd double-{beta} decay

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sasano, M.; Kuboki, H.; Sekiguchi, K.

2009-11-09

The double differential cross sections for the {sup 116}Cd(p,n) and {sup 116}Sn(n,p) reactions at 300 MeV have been measured over a wide excitation-energy region including Gamow-Teller (GT) giant resonance (GTGR) for studying GT transition strengths in the intermediate nucleus of the {sup 116}Cd double-{beta} decay, namely {sup 116}In. A large amount of the strengths in the {beta}{sup +} direction has been newly found in the energy region up to 30 MeV, which may imply that the GT strengths in the GTGR region contribute to the nuclear matrix element of the two-neutrino double-{beta} decay.

Pion emission in α-particle interactions with various targets of nuclear emulsion detector

NASA Astrophysics Data System (ADS)

Abdelsalam, A.; Abou-Moussa, Z.; Rashed, N.; M. Badawy, B.; A. Amer, H.; Osman, W.; M. El-Ashmawy, M.; Abdallah, N.

2015-09-01

The behavior of relativistic hadron multiplicity for 4He-nucleus interactions is investigated. The experiment is carried out at 2.1 A and 3.7 A GeV (Dubna energy) to search for the incident energy effect on the interactions inside different emulsion target nuclei. Data are presented in terms of the number of emitted relativistic hadrons in both forward and backward angular zones. The dependence on the target size is presented. For this purpose the statistical events are discriminated into groups according to the interactions with H, CNO, Em, and AgBr target nuclei. The separation of events, into the mentioned groups, is executed based on Glauber's multiple scattering theory approach. Features suggestive of a decay mechanism seem to be a characteristic of the backward emission of relativistic hadrons. The results strongly support the assumption that the relativistic hadrons may already be emitted during the de-excitation of the excited target nucleus, in a behavior like that of compound-nucleus disintegration. Regarding the limiting fragmentation hypothesis beyond 1 A GeV, the target size is the main parameter affecting the backward production of the relativistic hadron. The incident energy is a principal factor responsible for the forward relativistic hadron production, implying that this system of particle production is a creation system. However, the target size is an effective parameter as well as the projectile size considering the geometrical concept regarded in the nuclear fireball model. The data are analyzed in the framework of the FRITIOF model.

A review of electron-nucleus bremsstrahlung cross sections between 1 and 10 MeV

NASA Astrophysics Data System (ADS)

Mangiarotti, A.; Martins, M. N.

2017-12-01

More than 80 years have passed since the first calculations of electron-nucleus bremsstrahlung cross sections were published by Sommerfeld, for non-relativistic electrons, and, independently, by Sauter, Bethe and Heitler, and Racah, for relativistic electrons. The Bethe-Heitler expression, that is based on the first Born approximation and includes the screening of the Coulomb field of the nucleus by the atomic electrons, has proven to work well at moderately high energies where the Landau-Pomeranchuk-Migdal effect is negligible. We review the current theoretical and experimental status with a highlight on electrons with kinetic energies between 1 and 10 MeV. The choice is motivated by the peculiar difficulties present in this energy region, where it is necessary to treat simultaneously the interaction with the Coulomb field beyond the first Born approximation and the effect of screening. A fully numerical approach within the S-matrix formalism has proven to be extremely difficult above a few MeV, because the number of partial waves needed for an accurate evaluation is prohibitively large. Here we focus on analytic results, including the more complex ones employing the Furry-Sommerfeld-Maue wave functions and taking into account the next-to-leading order, and discuss the advantages and limitations in light of the best available data. The influence of multiple scattering in the target is investigated under the actual experimental conditions. A comparison with the widely used cross section tabulations by Seltzer and Berger is also presented.

Cellular dosimetry calculations for Strontium-90 using Monte Carlo code PENELOPE.

PubMed

Hocine, Nora; Farlay, Delphine; Boivin, Georges; Franck, Didier; Agarande, Michelle

2014-11-01

To improve risk assessments associated with chronic exposure to Strontium-90 (Sr-90), for both the environment and human health, it is necessary to know the energy distribution in specific cells or tissue. Monte Carlo (MC) simulation codes are extremely useful tools for calculating deposition energy. The present work was focused on the validation of the MC code PENetration and Energy LOss of Positrons and Electrons (PENELOPE) and the assessment of dose distribution to bone marrow cells from punctual Sr-90 source localized within the cortical bone part. S-values (absorbed dose per unit cumulated activity) calculations using Monte Carlo simulations were performed by using PENELOPE and Monte Carlo N-Particle eXtended (MCNPX). Cytoplasm, nucleus, cell surface, mouse femur bone and Sr-90 radiation source were simulated. Cells are assumed to be spherical with the radii of the cell and cell nucleus ranging from 2-10 μm. The Sr-90 source is assumed to be uniformly distributed in cell nucleus, cytoplasm and cell surface. The comparison of S-values calculated with PENELOPE to MCNPX results and the Medical Internal Radiation Dose (MIRD) values agreed very well since the relative deviations were less than 4.5%. The dose distribution to mouse bone marrow cells showed that the cells localized near the cortical part received the maximum dose. The MC code PENELOPE may prove useful for cellular dosimetry involving radiation transport through materials other than water, or for complex distributions of radionuclides and geometries.

Regulation of CCN2/CTGF Expression in the Nucleus Pulposus of the Intervertebral Disc: Role of Smad and AP1 Signaling

PubMed Central

Tran, Cassie M.; Markova, Dessislava; Smith, Harvey E.; Susarla, Bala; Ponnappan, Ravi Kumar; Anderson, D Greg; Symes, Aviva; Shapiro, Irving M.; Risbud, Makarand V.

2011-01-01

Objective To investigate TGFβ regulation of CTGF expression in cells of the nucleus pulposus. Methods Real Time RT-PCR and Western blot analysis was used to measure CTGF expression in the nucleus pulposus. Transfections were used to measure the effect of Smad2/3/7 and AP1on TGFβ mediated CTGF promoter activity. Results CTGF expression was lower in the neonatal disc compared with the skeletally mature rat disc. An increase in CTGF expression and promoter activity was observed in nucleus pulposus cells after TGFβ treatment. Deletion analysis indicated that promoter constructs lacking smad and AP1 motifs were unresponsive to treatment. Analysis showed that full-length Smad3 and the Smad3-MH2 domain alone increased CTGF activity. Further evidence of Smad3 and AP1 involvement was seen when DN-Smad3, SiRNA-Smad3, smad7 and DN-AP1 suppressed TGFβ mediated activation of the CTGF promoter. When either Smad3 or AP1 sites were mutated, CTGF promoter induction by TGFβ was suppressed. We also observed a decrease in expression of CTGF in discs of Smad3 null mice compared to the wild type. Analysis of human nucleus pulposus indicated a trend of increasing CTGF and TGFβ expression in the degenerate state. Conclusion TGFβ, through Smad3 and AP1, serves as a positive regulator of CTGF expression in the nucleus pulposus. We propose that CTGF is a part of the limited reparative response of the degenerate disc. PMID:20222112

The involvement of brain-derived neurotrophic factor in 3,4-methylenedioxymethamphetamine-induced place preference and behavioral sensitization.

PubMed

Mouri, Akihiro; Noda, Yukihiro; Niwa, Minae; Matsumoto, Yurie; Mamiya, Takayoshi; Nitta, Atsumi; Yamada, Kiyofumi; Furukawa, Shoei; Iwamura, Tatsunori; Nabeshima, Toshitaka

2017-06-30

3,4-Methylenedioxymethamphetamine (MDMA) is known to induce dependence and psychosis in humans. Brain-derived neurotrophic factor (BDNF) is involved in the synaptic plasticity and neurotrophy in midbrain dopaminergic neurons. This study aimed to investigate the role of BDNF in MDMA-induced dependence and psychosis. A single dose of MDMA (10mg/kg) induced BDNF mRNA expression in the prefrontal cortex, nucleus accumbens, and amygdala, but not in the striatum or the hippocampus. However, repeated MDMA administration for 7 days induced BDNF mRNA expression in the striatum and hippocampus. Both precursor and mature BDNF protein expression increased in the nucleus accumbens, mainly in the neurons. Additionally, rapidly increased extracellular serotonin levels and gradually and modestly increased extracellular dopamine levels were noted within the nucleus accumbens of mice after repeated MDMA administration. Dopamine receptor antagonists attenuated the effect of repeated MDMA administration on BDNF mRNA expression in the nucleus accumbens. To examine the role of endogenous BDNF in the behavioral and neurochemical effects of MDMA, we used mice with heterozygous deletions of the BDNF gene. MDMA-induced place preference, behavioral sensitization, and an increase in the levels of extracellular serotonin and dopamine within the nucleus accumbens, were attenuated in BDNF heterozygous knockout mice. These results suggest that BDNF is implicated in MDMA-induced dependence and psychosis by activating the midbrain serotonergic and dopaminergic neurons. Copyright © 2017 Elsevier B.V. All rights reserved.

Prolonged consumption of soy or fish-oil-enriched diets differentially affects the pattern of hypothalamic neuronal activation induced by refeeding in rats.

PubMed

Watanabe, Regina L H; Andrade, Iracema S; Zemdegs, Juliane C S; Albuquerque, Kelse T; Nascimento, Claudia M O; Oyama, Lila M; Carmo, Maria G T; Nogueira, Maria I; Ribeiro, Eliane B

2009-12-01

We used c-Fos immunoreactivity to estimate neuronal activation in hypothalamic feeding-regulatory areas of 3-month-old rats fed control or oil-enriched diets (soy or fish) since weaning. While no diet effect was observed in c-Fos immunoreactivity of 24-h fasted animals, the acute response to refeeding was modified by both hyperlipidic diets but with different patterns. Upon refeeding, control-diet rats had significantly increased c-Fos immunoreactivity only in the paraventricular hypothalamic nucleus (PVH, 142%). In soy-diet rats, refeeding with the soy diet increased c-Fos immunoreactivity in dorsomedial hypothalamic nucleus (DMH, 271%) and lateral hypothalamic area (LH, 303%). Refeeding fish-diet rats with the fish diet increased c-Fos immunoreactivity in PVH (161%), DMH (177%), VMH (81%), and ARC (127%). Compared to the fish-diet, c-Fos immunoreactivity was increased in LH by the soy-diet while it was decreased in ventromedial hypothalamic nucleus (VMH) and arcuate hypothalamic nucleus (ARC). Based on the known roles of the activated nuclei, it is suggested that, unlike the fish-diet, the soy-diet induced a potentially obesogenic profile, with high LH and low VMH/PVH activation after refeeding.

Prospects for detection of target-dependent annual modulation in direct dark matter searches

DOE PAGES

Nobile, Eugenio Del; Gelmini, Graciela B.; Witte, Samuel J.

2016-02-03

Earth's rotation about the Sun produces an annual modulation in the expected scattering rate at direct dark matter detection experiments. The annual modulation as a function of the recoil energy E R imparted by the dark matter particle to a target nucleus is expected to vary depending on the detector material. However, for most interactions a change of variables from E R to v min, the minimum speed a dark matter particle must have to impart a fixed E R to a target nucleus, produces an annual modulation independent of the target element. We recently showed that if the darkmore » matter-nucleus cross section contains a non-factorizable target and dark matter velocity dependence, the annual modulation as a function of v min can be target dependent. Here we examine more extensively the necessary conditions for target-dependent modulation, its observability in present-day experiments, and the extent to which putative signals could identify a dark matter-nucleus differential cross section with a non-factorizable dependence on the dark matter velocity.« less

Effect of complex configurations on the description of properties of {sup 132}Sn beta decay

DOE Office of Scientific and Technical Information (OSTI.GOV)

Severyukhin, A. P., E-mail: sever@theor.jinr.ru; Sushenok, E. O.

2015-07-15

Gamow–Teller transitions in the beta decay of the {sup 132}Sn neutron-rich nucleus was described microscopically. The coupling of one- and two-phonon components of the wave functions was taken into account on the basis of Skyrme interactions featuring various contributions of the tensor component. A separable approximation of the particle—hole interaction made it possible tohole interaction perform calculations in a large configuration space. It was shown that an increase in the strength of the neutron—proton tensor interaction led to an increase in the energy of Gamow—Teller transitions. In addition, a decrease in the {sup 132}Sn half-life with respect to beta decaymore » was obtained.« less

Energy distribution of relativistic electrons in the kiloparsec scale jet of M 87 with Chandra

NASA Astrophysics Data System (ADS)

Sun, Xiao-Na; Yang, Rui-Zhi; Rieger, Frank M.; Liu, Ruo-Yu; Aharonian, Felix

2018-05-01

The X-ray emission from the jets in active galactic nuclei (AGN) carries important information on the distributions of relativistic electrons and magnetic fields on large scales. We reanalysed archival Chandra observations on the jet of M 87 from 2000 to 2016 with a total exposure of 1460 kiloseconds to explore the X-ray emission characteristics along the jet. We investigated the variability behaviours of the nucleus and the inner jet component HST-1, and confirm indications for day-scale X-ray variability in the nucleus contemporaneous to the 2010 high TeV γ-ray state. HST-1 shows a general decline in X-ray flux over the last few years consistent with its synchrotron interpretation. We extracted the X-ray spectra for the nucleus and all knots in the jet, showing that they are compatible with a single power law within the X-ray band. There are indications that the resultant X-ray photon index exhibit a trend, with slight but significant index variations ranging from ≃ 2.2 (e.g. in knot D) to ≃ 2.4-2.6 (in the outer knots F, A, and B). When viewed in a multiwavelength context, a more complex situation can be seen. Fitting the radio to X-ray spectral energy distributions (SEDs) assuming a synchrotron origin, we show that a broken power-law electron spectrum with break energy Eb around 1 (300 μG/B)1/2 TeV allows a satisfactory description of the multiband SEDs for most of the knots. However, in the case of knots B, C, and D we find indications that an additional high-energy component is needed to adequately reproduce the broad-band SEDs. We discuss the implications and suggest that a stratified jet model may account for the differences.

High-resolution study of Gamow-Teller transitions in the 47Ti(3He,t)47V reaction

NASA Astrophysics Data System (ADS)

Ganioǧlu, E.; Fujita, H.; Fujita, Y.; Adachi, T.; Algora, A.; Csatlós, M.; Deaven, J. M.; Estevez-Aguado, E.; Guess, C. J.; Gulyás, J.; Hatanaka, K.; Hirota, K.; Honma, M.; Ishikawa, D.; Krasznahorkay, A.; Matsubara, H.; Meharchand, R.; Molina, F.; Okamura, H.; Ong, H. J.; Otsuka, T.; Perdikakis, G.; Rubio, B.; Scholl, C.; Shimbara, Y.; Susoy, G.; Suzuki, T.; Tamii, A.; Thies, J. H.; Zegers, R. G. T.; Zenihiro, J.

2013-01-01

Given the importance of Gamow-Teller (GT) transitions in nuclear structure and astrophysical nuclear processes, we have studied Tz=+3/2→+1/2, GT transitions starting from the 47Ti nucleus in the (3He,t) charge-exchange reaction at 0∘ and at an intermediate incident energy of 140 MeV/nucleon. The experiments were carried out at the Research Center for Nuclear Physics (RCNP), Osaka, using the high-resolution facility with a high-dispersion beam line and the Grand-Raiden spectrometer. With an energy resolution of 20 keV, individual GT transitions were observed and GT strength was derived for each state populated up to an excitation energy (Ex) of 12.5 MeV. The GT strength was widely distributed from low excitation energy up to 12.5 MeV, where we had to stop the analysis because of the high level density. The distribution of the GT strengths was compared with the results of shell model calculations using the GXPF1 interaction. The calculations could reproduce the experimental GT distributions well. The GT transitions from the ground state of 47Ti and the M1 transitions from the isobaric analog state in 47V to the same low-lying states in 47V are analogous. It was found that the ratios of GT transition strengths to the ground state, the 0.088-MeV state, and the 0.146-MeV state are similar to the ratios of the strengths of the analogous M1 transitions from the isobaric analog state (IAS) to these states. The measured distribution of the GT strengths was also compared with those starting from the Tz=+3/2 nucleus 41K to the Tz=+1/2 nucleus 41Ca.

Deletion of Protein Kinase C λ in POMC Neurons Predisposes to Diet-Induced Obesity

PubMed Central

Dorfman, Mauricio D.; Krull, Jordan E.; Scarlett, Jarrad M.; Guyenet, Stephan J.; Sajan, Mini P.; Damian, Vincent; Nguyen, Hong T.; Leitges, Michael; Morton, Gregory J.; Farese, Robert V.; Schwartz, Michael W.

2017-01-01

Effectors of the phosphoinositide 3-kinase (PI3K) signal transduction pathway contribute to the hypothalamic regulation of energy and glucose homeostasis in divergent ways. Here we show that central nervous system (CNS) action of the PI3K signaling intermediate atypical protein kinase C (aPKC) constrains food intake, weight gain, and glucose intolerance in both rats and mice. Pharmacological inhibition of CNS aPKC activity acutely increases food intake and worsens glucose tolerance in chow-fed rodents and causes excess weight gain during high-fat diet (HFD) feeding. Similarly, selective deletion of the aPKC isoform Pkc-λ in proopiomelanocortin (POMC) neurons disrupts leptin action, reduces melanocortin content in the paraventricular nucleus, and markedly increases susceptibility to obesity, glucose intolerance, and insulin resistance specifically in HFD-fed male mice. These data implicate aPKC as a novel regulator of energy and glucose homeostasis downstream of the leptin-PI3K pathway in POMC neurons. PMID:28073831

CDK1 enhances mitochondrial bioenergetics for radiation-induced DNA repair

DOE PAGES

Qin, Lili; Fan, Ming; Candas, Demet; ...

2015-12-06

Nuclear DNA repair capacity is a critical determinant of cell fate under genotoxic stress conditions. DNA repair is a well-defined energy-consuming process. However, it is unclear how DNA repair is fueled and whether mitochondrial energy production contributes to nuclear DNA repair. Here, we report a dynamic enhancement of oxygen consumption and mitochondrial ATP generation in irradiated normal cells, paralleled with increased mitochondrial relocation of the cell-cycle kinase CDK1 and nuclear DNA repair. The basal and radiation-induced mitochondrial ATP generation is reduced significantly in cells harboring CDK1 phosphorylation-deficient mutant complex I subunits. Similarly, mitochondrial ATP generation and nuclear DNA repair aremore » also compromised severely in cells harboring mitochondrially targeted, kinase-deficient CDK1. These findings demonstrate a mechanism governing the communication between mitochondria and the nucleus by which CDK1 boosts mitochondrial bioenergetics to meet the increased cellular fuel demand for DNA repair and cell survival under genotoxic stress conditions.« less

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

NASA Astrophysics Data System (ADS)

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

2012-12-01

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

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

NASA Astrophysics Data System (ADS)

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

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

Expression and distribution of TRPV2 in rat brain.

PubMed

Nedungadi, Thekkethil Prashant; Dutta, Mayurika; Bathina, Chandra Sekhar; Caterina, Michael J; Cunningham, J Thomas

2012-09-01

Transient receptor potential (TRP) proteins are non-selective cation channels that mediate sensory transduction. The neuroanatomical localization and the physiological roles of isoform TRPV2 in the rodent brain are largely unknown. We report here the neuroanatomical distribution of TRPV2 in the adult male rat brain focusing on the hypothalamus and hindbrain regions involved in osmoregulation, autonomic function and energy metabolism. For this we utilized immunohistochemistry combined with brightfield microscopy. In the forebrain, the densest immunostaining was seen in both the supraoptic nucleus (SON) and the magnocellular division of the paraventricular nucleus (PVN) of the hypothalamus. TRPV2 immunoreactivity was also seen in the organum vasculosum of the lamina terminalis, the median preoptic nucleus and the subfornical organ, in addition to the arcuate nucleus of the hypothalamus (ARH), the medial forebrain bundle, the cingulate cortex and the globus pallidus to name a few. In the hindbrain, intense staining was seen in the nucleus of the solitary tract, hypoglossal nucleus, nucleus ambiguous, and the rostral division of the ventrolateral medulla (RVLM) and some mild staining in the area prostrema. To ascertain the specificity of the TRPV2 antibody used in this paper, we compared the TRPV2 immunoreactivity of wildtype (WT) and knockout (KO) mouse brain tissue. Double immunostaining with arginine vasopressin (AVP) using confocal microscopy showed a high degree of colocalization of TRPV2 in the magnocellular SON and PVN. Using laser capture microdissection (LCM) we also show that AVP neurons in the SON contain TRPV2 mRNA. TRPV2 was also co-localized with dopamine beta hydroxylase (DBH) in the NTS and the RVLM of the hindbrain. Based on our results, TRPV2 may play an important role in several CNS networks that regulate body fluid homeostasis, autonomic function, and metabolism. Copyright © 2012 Elsevier Inc. All rights reserved.

Expression and Distribution of TRPV2 in Rat Brain

PubMed Central

Nedungadi, Thekkethil Prashant; Dutta, Mayurika; Bathina, Chandra Sekhar; Caterina, Michael J; Cunningham, J. Thomas

2012-01-01

Transient receptor potential (TRP) proteins are non-selective cation channels that mediate sensory transduction. The neuroanatomical localization and the physiological roles of isoform TRPV2 in the rodent brain are largely unknown. We report here the neuroanatomical distribution of TRPV2 in the adult male rat brain focusing on hypothalamus and hindbrain regions involved in osmoregulation, autonomic function and energy metabolism. For this we utilized immunohistochemistry combined with brighfield microscopy. In the forebrain, the densest immunostaining was seen in both the supraoptic nucleus (SON) and the magnocellular division of the paraventricular nucleus (PVN) of the hypothalamus. TRPV2 immunoreactivity was also seen in the organum vasculosum of the lamina terminalis, the median preoptic nucleus and the subfornical organ, in addition to the arcuate nucleus of the hypothalamus (ARH), the medial forebrain bundle, the cingulate cortex and the globus pallidus to name a few. In the hindbrain, intense staining was seen in the nucleus of the solitary tract, hypoglossal nucleus, nucleus ambiguous, and the rostral division of the ventrolateral medulla (RVLM) and some mild staining in the area prostrema. To ascertain the specificity of the TRPV2 antibody used in this paper, we compared the TRPV2 immunoreactivity of wildtype (WT) and knockout (KO) mouse brain tissue. Double immunostaining with arginine vasopressin (AVP) using confocal microscopy showed a high degree of colocalization of TRPV2 in the magnocellular SON and PVN. Using laser capture microdissection (LCM) we also show that AVP neurons in the SON contain TRPV2 mRNA. TRPV2 was also co-localized with dopamine beta hydroxylase (DBH) in the NTS and the RVLM of the hindbrain. Based on our results, TRPV2 may play an important role in several CNS networks that regulate body fluid homeostasis, autonomic function, and metabolism. PMID:22750329

Environmental enrichment alters protein expression as well as the proteomic response to cocaine in rat nucleus accumbens

PubMed Central

Lichti, Cheryl F.; Fan, Xiuzhen; English, Robert D.; Zhang, Yafang; Li, Dingge; Kong, Fanping; Sinha, Mala; Andersen, Clark R.; Spratt, Heidi; Luxon, Bruce A.; Green, Thomas A.

2014-01-01

Prior research demonstrated that environmental enrichment creates individual differences in behavior leading to a protective addiction phenotype in rats. Understanding the mechanisms underlying this phenotype will guide selection of targets for much-needed novel pharmacotherapeutics. The current study investigates differences in proteome expression in the nucleus accumbens of enriched and isolated rats and the proteomic response to cocaine self-administration using a liquid chromatography mass spectrometry (LCMS) technique to quantify 1917 proteins. Results of complementary Ingenuity Pathways Analyses (IPA) and gene set enrichment analyses (GSEA), both performed using protein quantitative data, demonstrate that cocaine increases vesicular transporters for dopamine and glutamate as well as increasing proteins in the RhoA pathway. Further, cocaine regulates proteins related to ERK, CREB and AKT signaling. Environmental enrichment altered expression of a large number of proteins implicated in a diverse number of neuronal functions (e.g., energy production, mRNA splicing, and ubiquitination), molecular cascades (e.g., protein kinases), psychiatric disorders (e.g., mood disorders), and neurodegenerative diseases (e.g., Huntington's and Alzheimer's diseases). Upregulation of energy metabolism components in EC rats was verified using RNA sequencing. Most of the biological functions and pathways listed above were also identified in the Cocaine X Enrichment interaction analysis, providing clear evidence that enriched and isolated rats respond quite differently to cocaine exposure. The overall impression of the current results is that enriched saline-administering rats have a unique proteomic complement compared to enriched cocaine-administering rats as well as saline and cocaine-taking isolated rats. These results identify possible mechanisms of the protective phenotype and provide fertile soil for developing novel pharmacotherapeutics. Proteomics data are available via ProteomeXchange with identifier PXD000990. PMID:25100957

Mct8 and trh co-expression throughout the hypothalamic paraventricular nucleus is modified by dehydration-induced anorexia in rats.

PubMed

Alvarez-Salas, Elena; Mengod, Guadalupe; García-Luna, Cinthia; Soberanes-Chávez, Paulina; Matamoros-Trejo, Gilberto; de Gortari, Patricia

2016-04-01

Thyrotropin-releasing hormone (TRH) is a neuropeptide with endocrine and neuromodulatory effects. TRH from the paraventricular hypothalamic nucleus (PVN) participates in the control of energy homeostasis; as a neuromodulator TRH has anorexigenic effects. Negative energy balance decreases PVN TRH expression and TSH concentration; in contrast, a particular model of anorexia (dehydration) induces in rats a paradoxical increase in TRH expression in hypophysiotropic cells from caudal PVN and high TSH serum levels, despite their apparent hypothalamic hyperthyroidism and low body weight. We compared here the mRNA co-expression pattern of one of the brain thyroid hormones' transporters, the monocarboxylate transporter-8 (MCT8) with that of TRH in PVN subdivisions of dehydration-induced anorexic (DIA) and control rats. Our aim was to identify whether a low MCT8 expression in anorexic rats could contribute to their high TRH mRNA content.We registered daily food intake and body weight of 7-day DIA and control rats and analyzed TRH and MCT8 mRNA co-expression throughout the PVN by double in situ hybridization assays. We found that DIA rats showed increased number of TRHergic cells in caudal PVN, as well as a decreased percentage of TRH-expressing neurons that co-expressed MCT8 mRNA signal. Results suggest that the reduced proportion of double TRH/MCT8 expressing cells may be limiting the entry of hypothalamic triiodothyronine to the greater number of TRH-expressing neurons from caudal PVN and be in part responsible for the high TRH expression in anorexia rats and for the lack of adaptation of their hypothalamic-pituitary-thyroid axis to their low food intake.

Dynamic interaction between actin and nesprin2 maintain the cell nucleus in a prestressed state

NASA Astrophysics Data System (ADS)

Kumar, Abhishek; Shivashankar, G. V.

2016-12-01

Mechanical coupling between the nucleus and the cytoskeleton is indispensable for direct force transduction from the extra cellular matrix (ECM) to the chromatin. Although this physical coupling has been shown to be crucial for nuclear positioning and its function, the quantification of nuclear-cytoskeleton interaction has been lacking. In this paper, using various quantitative fluorescence spectroscopy techniques, we investigate the nature of this connection. High-resolution 3D imaging shows that nesprin2G forms short linear structures along actin stress fibers (ASFs) in the apical region of the nucleus. Fluorescence recovery after photobleaching (FRAP) revealed that the alignment of nesprin2G becomes heterogeneous when cell shape is engineered from elongated rectangular shape to square using micropatterned substrates. Further, fluorescence cross-correlation spectroscopy (FCCS) revealed that actin interacts transiently with outer nuclear membrane protein nesprin2G with a time scale of 12 ms. In addition, fluorescence resonance energy transfer (FRET) experiments show that the apical ASFs and nesprin2G are in close physical proximity. This interaction is spatially heterogeneous with high FRET along the ASFs. Lastly, we show that the disruption of actin to nuclear connection by over-expression of Dominant Negative Klarsicht, ANC-1, Syne Homology (DNKASH) leads to an increase in nuclear height. These results not only reveal the characteristics of actin-nesprin2G interaction and its significance in regulating nuclear morphology, but also validate the utility of quantitative fluorescence techniques in deciphering physical connections that are essential for mechanotransduction.

Purinergic A2b Receptor Activation by Extracellular Cues Affects Positioning of the Centrosome and Nucleus and Causes Reduced Cell Migration.

PubMed

Ou, Young; Chan, Gordon; Zuo, Jeremy; Rattner, Jerome B; van der Hoorn, Frans A

2016-07-15

The tight, relative positioning of the nucleus and centrosome in mammalian cells is important for the regulation of cell migration. Under pathophysiological conditions, the purinergic A2b receptor can regulate cell motility, but the underlying mechanism remains unknown. Expression of A2b, normally low, is increased in tissues experiencing adverse physiological conditions, including hypoxia and inflammation. ATP is released from such cells. We investigated whether extracellular cues can regulate centrosome-nucleus positioning and cell migration. We discovered that hypoxia as well as extracellular ATP cause a reversible increase in the distance between the centrosome and nucleus and reduced cell motility. We uncovered the underlying pathway: both treatments act through the A2b receptor and specifically activate the Epac1/RapGef3 pathway. We show that cells lacking A2b do not respond in this manner to hypoxia or ATP but transfection of A2b restores this response, that Epac1 is critically involved, and that Rap1B is important for the relative positioning of the centrosome and nucleus. Our results represent, to our knowledge, the first report demonstrating that pathophysiological conditions can impact the distance between the centrosome and nucleus. Furthermore, we identify the A2b receptor as a central player in this process. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Purinergic A2b Receptor Activation by Extracellular Cues Affects Positioning of the Centrosome and Nucleus and Causes Reduced Cell Migration*

PubMed Central

Ou, Young; Chan, Gordon; Zuo, Jeremy; Rattner, Jerome B.; van der Hoorn, Frans A.

2016-01-01

The tight, relative positioning of the nucleus and centrosome in mammalian cells is important for the regulation of cell migration. Under pathophysiological conditions, the purinergic A2b receptor can regulate cell motility, but the underlying mechanism remains unknown. Expression of A2b, normally low, is increased in tissues experiencing adverse physiological conditions, including hypoxia and inflammation. ATP is released from such cells. We investigated whether extracellular cues can regulate centrosome-nucleus positioning and cell migration. We discovered that hypoxia as well as extracellular ATP cause a reversible increase in the distance between the centrosome and nucleus and reduced cell motility. We uncovered the underlying pathway: both treatments act through the A2b receptor and specifically activate the Epac1/RapGef3 pathway. We show that cells lacking A2b do not respond in this manner to hypoxia or ATP but transfection of A2b restores this response, that Epac1 is critically involved, and that Rap1B is important for the relative positioning of the centrosome and nucleus. Our results represent, to our knowledge, the first report demonstrating that pathophysiological conditions can impact the distance between the centrosome and nucleus. Furthermore, we identify the A2b receptor as a central player in this process. PMID:27226580

GEANT 4 simulation of (99)Mo photonuclear production in nanoparticles.

PubMed

Dikiy, N P; Dovbnya, A N; Fedorchenko, D V; Khazhmuradov, M A

2016-08-01

GEANT 4 Monte-Carlo simulation toolkit is used to study the kinematic recoil method of (99)Mo photonuclear production. Simulation for bremsstrahlung photon spectrum with maximum photon energy 30MeV showed that for MoO3 nanoparticle escape fraction decreases from 0.24 to 0.08 when nanoparticle size increases from 20nm to 80nm. For the natural molybdenum and pure (100)Mo we obtained the lower values: from 0.17 to 0.05. The generation of accompanying molybdenum nuclei is significantly lower for pure (100)Mo and is about 3.6 nuclei per single (99)Mo nucleus, while natural molybdenum nanoparticle produce about 48 accompanying nuclei. Also, we have shown that for high-energy photons escape fraction of (99)Mo decreases, while production of unwanted molybdenum isotopes is significantly higher. Copyright © 2016 Elsevier Ltd. All rights reserved.

Does a continuous solid nucleus exist in comets.

NASA Technical Reports Server (NTRS)

Lyttleton, R. A.

1972-01-01

The implication of actual cometary observations for the physical nature of comets is briefly reviewed, bringing out the complete conflict with observation of the ice-dust solid nucleus model put forward in recent years as representing the fundamental structure of comets. That under increasing solar heat the nucleus develops an expanding atmosphere is inconsistent with the well-established phenomenon that the coma contracts with decreasing distance from the sun. Several comets remaining always beyond Mars have nevertheless been strongly active and produced fine tails. That some comets show at times a star-like point of light is readily explicable on the dust-cloud structure and by no means establishes that a solid nucleus exists. With the nucleus-area corresponding not to a small solid mass but to an optical phenomenon, there would be no reason to expect that it would describe a precise dynamical orbit. On the hypothesis of a nucleus, it is necessary to postulate further some internal jet-propulsion mechanism to account for the orbital deviations.

Mapping out the QCD phase transition in multiparticle production

NASA Astrophysics Data System (ADS)

Kabana, Sonja; Minkowski, Peter

2001-04-01

We analyse multiparticle production in a thermal framework for seven central nucleus + nucleus collisions, e+ + e- annihilation into hadrons on the Z resonance and four hadronic reactions p + p and p + pbar with partial centrality selection), with centre of mass energies ranging from √(s) = 2.6 GeV (per nucleon pair) to 1.8 TeV. Thermodynamic parameters at chemical freeze-out (temperature and baryon and strangeness fugacities) are obtained from appropriate fits, generally improving in quality for reactions subjected to centrality cuts. All systems with non-vanishing fugacities are extrapolated along trajectories of equal energy density, density and entropy density to zero fugacities. The so-obtained temperatures extrapolated to zero fugacities as a function of initial energy density ɛin universally show a strong rise followed by a saturating limit of Tlim = 155 +/- 6 +/- 20 MeV. We interpret this behaviour as mapping out the boundary between quark gluon plasma and hadronic phases. The ratio of strange antiquarks to light ones as a function of the initial energy density ɛin shows the same behaviour as the temperature, saturating at a value of 0.365 +/- 0.033 +/- 0.07. No distinctive feature of `strangeness enhancement' is seen for heavy ion collisions relative to hadronic and leptonic reactions, when compared at the same initial energy density.

Reexamining the role of the (n ,γ f ) process in the low-energy fission of 235U and 239Pu

NASA Astrophysics Data System (ADS)

Lynn, J. E.; Talou, P.; Bouland, O.

2018-06-01

The (n ,γ f ) process is reviewed in light of modern nuclear reaction calculations in both slow and fast neutron-induced fission reactions on 235U and 239Pu. Observed fluctuations of the average prompt fission neutron multiplicity and average total γ -ray energy below 100-eV incident neutron energy are interpreted in this framework. The surprisingly large contribution of the M 1 transitions to the prefission γ -ray spectrum of 239Pu is explained by the dominant fission probabilities of 0+ and 2+ transition states, which can only be accessed from compound nucleus states formed by the interaction of s -wave neutrons with the target nucleus in its ground state, and decaying through M 1 transitions. The impact of an additional low-lying M 1 scissors mode in the photon strength function is analyzed. We review experimental evidence for fission fragment mass and kinetic-energy fluctuations in the resonance region and their importance in the interpretation of experimental data on prompt neutron data in this region. Finally, calculations are extended to the fast energy range where (n ,γ f ) corrections can account for up to 3% of the total fission cross section and about 20% of the capture cross section.

Summary talk: Experiments at low energies

NASA Astrophysics Data System (ADS)

Leifels, Yvonne

2016-01-01

In heavy-ion collisions at beam energies √sNN between 1 and 150A GeV highest baryonic densities are reached at rather moderate temperatures. By varying the beam energy and the system size a broad range of the QCD phase diagram is scanned where several interesting phenomena are predicted by theoretical models. Apart from possible phase transitions and existence of a critical point in this regime, the production of strangeness and the interaction of strange particles with the surrounding hot and dense nuclear medium constitutes a prominent probe not only to address the underlying reaction mechanisms and production processes but in particular to constrain densities and temperatures reached in the course of the collision. Recent results on heavy-ion collisions in this beam energy regime obtained by various experimental collaborations are summarized, with special emphasis on strangeness production, rare probes, and critical phenomena. The importance of data on elementary reactions (i.e., pp, p+nucleus, and π+nucleus) as a bench mark for theoretical models and their relevance for understanding the underlying mechanisms of heavy-ion collisions are being discussed. Several interesting observables have been presented in various contributions, which give further motivation for the construction of high-rate experiments at new accelerator facilities.

An alarm pheromone reduces ventral tegmental area-nucleus accumbens shell responsivity.

PubMed

Gutiérrez-García, Ana G; Contreras, Carlos M; Saldivar-Lara, Mauricio

2018-06-21

2-Heptanone (methyl n-amyl ketone) is a ketone that produces alarm reactions in insects (e.g., bees and ants). As an olfactory stimulus, 2-heptanone produces anxiety reactions in the short term and despair in the long term in rodent models. Among the anatomical connections of the olfactory system that integrate behavioral responses, connections between the amygdala and nucleus accumbens are important, which in turn form a circuit with the ventral tegmental area (VTA). 2-Heptanone increases the firing rate of amygdala neurons without participation of the vomeronasal organ. The olfactory amygdala-VTA-nucleus accumbens circuit may integrate defensive behaviors, but the possible actions of 2-heptanone on the responsivity of VTA-nucleus accumbens connections have not yet been explored. In the present study, multiunit activity recordings were obtained in adult Wistar rats from the core and shell subregions of the nucleus accumbens during electrical stimulation of the VTA under basal conditions and later during simultaneous stimulation of the VTA and olfactory exposure to 2-heptanone. 2-Heptanone reduced the responsivity of the VTA-nucleus accumbens shell but did not influence the responsivity of the VTA-nucleus accumbens core. The lower VTA-nucleus accumbens shell excitability may be related to a primary defensive warning when exposed to an alarm pheromone. Copyright © 2018 Elsevier B.V. All rights reserved.

PPG neurons of the lower brain stem and their role in brain GLP-1 receptor activation

PubMed Central

Cork, Simon C.

2015-01-01

Within the brain, glucagon-like peptide-1 (GLP-1) affects central autonomic neurons, including those controlling the cardiovascular system, thermogenesis, and energy balance. Additionally, GLP-1 influences the mesolimbic reward system to modulate the rewarding properties of palatable food. GLP-1 is produced in the gut and by hindbrain preproglucagon (PPG) neurons, located mainly in the nucleus tractus solitarii (NTS) and medullary intermediate reticular nucleus. Transgenic mice expressing glucagon promoter-driven yellow fluorescent protein revealed that PPG neurons not only project to central autonomic control regions and mesolimbic reward centers, but also strongly innervate spinal autonomic neurons. Therefore, these brain stem PPG neurons could directly modulate sympathetic outflow through their spinal inputs to sympathetic preganglionic neurons. Electrical recordings from PPG neurons in vitro have revealed that they receive synaptic inputs from vagal afferents entering via the solitary tract. Vagal afferents convey satiation to the brain from signals like postprandial gastric distention or activation of peripheral GLP-1 receptors. CCK and leptin, short- and long-term satiety peptides, respectively, increased the electrical activity of PPG neurons, while ghrelin, an orexigenic peptide, had no effect. These findings indicate that satiation is a main driver of PPG neuronal activation. They also show that PPG neurons are in a prime position to respond to both immediate and long-term indicators of energy and feeding status, enabling regulation of both energy balance and general autonomic homeostasis. This review discusses the question of whether PPG neurons, rather than gut-derived GLP-1, are providing the physiological substrate for the effects elicited by central nervous system GLP-1 receptor activation. PMID:26290108

PPG neurons of the lower brain stem and their role in brain GLP-1 receptor activation.

PubMed

Trapp, Stefan; Cork, Simon C

2015-10-15

Within the brain, glucagon-like peptide-1 (GLP-1) affects central autonomic neurons, including those controlling the cardiovascular system, thermogenesis, and energy balance. Additionally, GLP-1 influences the mesolimbic reward system to modulate the rewarding properties of palatable food. GLP-1 is produced in the gut and by hindbrain preproglucagon (PPG) neurons, located mainly in the nucleus tractus solitarii (NTS) and medullary intermediate reticular nucleus. Transgenic mice expressing glucagon promoter-driven yellow fluorescent protein revealed that PPG neurons not only project to central autonomic control regions and mesolimbic reward centers, but also strongly innervate spinal autonomic neurons. Therefore, these brain stem PPG neurons could directly modulate sympathetic outflow through their spinal inputs to sympathetic preganglionic neurons. Electrical recordings from PPG neurons in vitro have revealed that they receive synaptic inputs from vagal afferents entering via the solitary tract. Vagal afferents convey satiation to the brain from signals like postprandial gastric distention or activation of peripheral GLP-1 receptors. CCK and leptin, short- and long-term satiety peptides, respectively, increased the electrical activity of PPG neurons, while ghrelin, an orexigenic peptide, had no effect. These findings indicate that satiation is a main driver of PPG neuronal activation. They also show that PPG neurons are in a prime position to respond to both immediate and long-term indicators of energy and feeding status, enabling regulation of both energy balance and general autonomic homeostasis. This review discusses the question of whether PPG neurons, rather than gut-derived GLP-1, are providing the physiological substrate for the effects elicited by central nervous system GLP-1 receptor activation. Copyright © 2015 the American Physiological Society.

Automated pipeline to analyze non-contact infrared images of the paraventricular nucleus specific leptin receptor knock-out mouse model

NASA Astrophysics Data System (ADS)

Diaz Martinez, Myriam; Ghamari-Langroudi, Masoud; Gifford, Aliya; Cone, Roger; Welch, E. B.

2015-03-01

Evidence of leptin resistance is indicated by elevated leptin levels together with other hallmarks of obesity such as a defect in energy homeostasis.1 As obesity is an increasing epidemic in the US, the investigation of mechanisms by which leptin resistance has a pathophysiological impact on energy is an intensive field of research.2 However, the manner in which leptin resistance contributes to the dysregulation of energy, specifically thermoregulation,3 is not known. The aim of this study was to investigate whether the leptin receptor expressed in paraventricular nucleus (PVN) neurons plays a role in thermoregulation at different temperatures. Non-contact infrared (NCIR) thermometry was employed to measure surface body temperature (SBT) of nonanesthetized mice with a specific deletion of the leptin receptor in the PVN after exposure to room (25 °C) and cold (4 °C) temperature. Dorsal side infrared images of wild type (LepRwtwt/sim1-Cre), heterozygous (LepRfloxwt/sim1-Cre) and knock-out (LepRfloxflox/sim1-Cre) mice were collected. Images were input to an automated post-processing pipeline developed in MATLAB to calculate average and maximum SBTs. Linear regression was used to evaluate the relationship between sex, cold exposure and leptin genotype with SBT measurements. Findings indicate that average SBT has a negative relationship to the LepRfloxflox/sim1-Cre genotype, the female sex and cold exposure. However, max SBT is affected by the LepRfloxflox/sim1-Cre genotype and the female sex. In conclusion this data suggests that leptin within the PVN may have a neuroendocrine role in thermoregulation and that NCIR thermometry combined with an automated imaging-processing pipeline is a promising approach to determine SBT in non-anesthetized mice.

Cavitation in a metallic liquid: Homogeneous nucleation and growth of nanovoids

NASA Astrophysics Data System (ADS)

Cai, Y.; Wu, H. A.; Luo, S. N.

2014-06-01

Large-scale molecular dynamics (MD) simulations are performed to investigate homogeneous nucleation and growth of nanovoids during cavitation in liquid Cu. We characterize in detail the atomistic cavitation processes by following the temporal evolution of cavities or voids, analyze the nucleation behavior with the mean first-passage time (MFPT) and survival probability (SP) methods, and discuss the results against classical nucleation theory (CNT), the Tolman equation for surface energy, independent calculation of surface tension via integrating the stress profiles, the Johnson-Mehl-Avrami (JMA) growth law, and the power law for nucleus size distributions. Cavitation in this representative metallic liquid is a high energy barrier Poisson processes, and the steady-state nucleation rates obtained from statistical runs with the MFPT and SP methods are in agreement. The MFPT method also yields the critical nucleus size and the Zeldovich factor. Fitting with the Tolman's equation to the MD simulations yields the surface energy of a planar interface (˜0.9 J {m}^{-2}) and the Tolman length (0.4-0.5 Å), and those values are in accord with those from integrating the stress profiles of a planar interface. Independent CNT predictions of the nucleation rate (1033 - 34 s-1 m-3) and critical size (3-4 Å in radius) are in agreement with the MFPT and SP results. The JMA law can reasonably describe the nucleation and growth process. The size distribution of subcritical nuclei appears to follow a power law with an exponent decreasing with increasing tension owing to coupled nucleation and growth, and that of the supercritical nuclei becomes flattened during further stress relaxation due to void coalescence.

Cavitation in a metallic liquid: homogeneous nucleation and growth of nanovoids.

PubMed

Cai, Y; Wu, H A; Luo, S N

2014-06-07

Large-scale molecular dynamics (MD) simulations are performed to investigate homogeneous nucleation and growth of nanovoids during cavitation in liquid Cu. We characterize in detail the atomistic cavitation processes by following the temporal evolution of cavities or voids, analyze the nucleation behavior with the mean first-passage time (MFPT) and survival probability (SP) methods, and discuss the results against classical nucleation theory (CNT), the Tolman equation for surface energy, independent calculation of surface tension via integrating the stress profiles, the Johnson-Mehl-Avrami (JMA) growth law, and the power law for nucleus size distributions. Cavitation in this representative metallic liquid is a high energy barrier Poisson processes, and the steady-state nucleation rates obtained from statistical runs with the MFPT and SP methods are in agreement. The MFPT method also yields the critical nucleus size and the Zeldovich factor. Fitting with the Tolman's equation to the MD simulations yields the surface energy of a planar interface (~0.9 J m⁻²) and the Tolman length (0.4-0.5 Å), and those values are in accord with those from integrating the stress profiles of a planar interface. Independent CNT predictions of the nucleation rate (10(33 - 34) s(-1) m(-3)) and critical size (3-4 Å in radius) are in agreement with the MFPT and SP results. The JMA law can reasonably describe the nucleation and growth process. The size distribution of subcritical nuclei appears to follow a power law with an exponent decreasing with increasing tension owing to coupled nucleation and growth, and that of the supercritical nuclei becomes flattened during further stress relaxation due to void coalescence.

Effect of repulsive and attractive three-body forces on nucleus-nucleus elastic scattering

DOE Office of Scientific and Technical Information (OSTI.GOV)

Furumoto, T.; Sakuragi, Y.; Yamamoto, Y.

2009-10-15

The effect of the three-body force (TBF) is studied in nucleus-nucleus elastic scattering on the basis of Brueckner theory for nucleon-nucleon (NN) effective interaction (complex G matrix) in the nuclear matter. A new G matrix called CEG07 proposed recently by the present authors includes the TBF effect and reproduces a realistic saturation curve in the nuclear matter, and it is shown to well reproduce proton-nucleus elastic scattering. The microscopic optical potential for the nucleus-nucleus system is obtained by folding the G matrix with nucleon density distributions in colliding nuclei. We first analyze in detail the {sup 16}O+{sup 16}O elastic scatteringmore » at E/A=70 MeV. The observed cross sections are nicely reproduced up to the most backward scattering angles only when the TBF effect is included. The use of the frozen-density approximation (FDA) is essentially important to properly estimate the effect of the TBF in nucleus-nucleus scattering. Other prescriptions for defining the local density have also been tested, but only the FDA prescription gives a proper description of the experimental cross sections as well as the effect of the TBF. The effects of the three-body attraction and the {omega}-rearrangement term are also analyzed. The CEG07 interaction is compared with CDM3Y6, which is a reliable and successful effective density-dependent NN interaction used in the double-folding model. The CEG07 G matrix is also tested in the elastic scattering of {sup 16}O by the {sup 12}C, {sup 28}Si, and {sup 40}Ca targets at E/A=93.9 MeV, and in the elastic scattering of {sup 12}C by the {sup 12}C target at E/A=135 MeV with great success. The decisive effect of the TBF is clearly seen also in those systems. Finally, we have tested CEG07a, CEG07b, and CEG07c for the {sup 16}O+{sup 16}O system at various energies.« less

Gold nanoparticle-aided brachytherapy with vascular dose painting: estimation of dose enhancement to the tumor endothelial cell nucleus.

PubMed

Ngwa, Wilfred; Makrigiorgos, G Mike; Berbeco, Ross I

2012-01-01

Theoretical microdosimetry at the subcellular level is employed in this study to estimate the dose enhancement to tumor endothelial cell nuclei, caused by radiation-induced photo/Auger electrons originating from gold nanoparticles (AuNPs) targeting the tumor endothelium, during brachytherapy. A tumor vascular endothelial cell (EC) is modeled as a slab of 2 μm (thickness) × 10 μm (length) × 10 μm (width). The EC contains a nucleus of 5 μm diameter and thickness of 0.5-1 μm, corresponding to nucleus size 5%-10% of cellular volume, respectively. Analytic calculations based on the electron energy loss formula of Cole were carried out to estimate the dose enhancement to the nucleus caused by photo/Auger electrons from AuNPs attached to the exterior surface of the EC. The nucleus dose enhancement factor (nDEF), representing the ratio of the dose to the nucleus with and without the presence of gold nanoparticles was calculated for different AuNP local concentrations. The investigated concentration range considers the potential for significantly higher local concentration near the EC due to preferential accumulation of AuNP in the tumor vasculature. Four brachytherapy sources: I-125, Pd-103, Yb-169, and 50 kVp x-rays were investigated. For nucleus size of 10% of the cellular volume and AuNP concentrations ranging from 7 to 140 mg/g, brachytherapy sources Pd-103, I-125, 50 kVp, and Yb-169 yielded nDEF values of 5.6-73, 4.8-58.3, 4.7-56.6, and 3.2-25.8, respectively. Meanwhile, for nucleus size 5% of the cellular volume in the same concentration range, Pd-103, I-125, 50 kVp, and Yb-169 yielded nDEF values of 6.9-79.2, 5.1-63.2, 5.0-61.5, and 3.3-28.3, respectively. The results predict that a substantial dose boost to the nucleus of endothelial cells can be achieved by applying tumor vasculature-targeted AuNPs in combination with brachytherapy. Such vascular dose boosts could induce tumor vascular shutdown, prompting extensive tumor cell death.

Role of Electronic Structure In Ion Band State Theory of Low Energy Nuclear Reactions

NASA Astrophysics Data System (ADS)

Chubb, Scott

2004-03-01

The Nuts and Bolts of our Ion Band State (IBS) theory of low energy nuclear reactions (LENR's) in palladium-deuteride (PdD) and palladium-hydride (PdH) are the electrons that hold together or tear apart the bonds (or lack of bonds) between deuterons (d's) or protons (p's) and the host material. In PdDx and PdH_x, this bonding is strongly correlated with loading: in ambient loading conditions (x< 0. 6), the bonding in hibits IBS occupation. As x arrow 1, slight increases and decreases in loading can lead to vibrations (which have conventionally been thought to occur from phonons) that can induce potential losses or increases of p/d. Naive assumptions about phonons fail to include these losses and increases. These effects can occur because neither H or D has core electrons and because in either PdD or PdH, the electrons near the Fermi Energy have negligible overlap with the nucleus of either D or H. I use these ideas to develop a formal justification, based on a generalization of conventional band theory (Scott Chubb, "Semi-Classical Conduction of Charged and Neutral Particles in Finite Lattices," 2004 March Meeting."), for the idea that occupation of IBS's can occur and that this can lead to nuclear reactions.

Pseudorapidity configurations in collisions between gold nuclei and track-emulsion nuclei

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gulamov, K. G.; Zhokhova, S. I.; Lugovoi, V. V., E-mail: lugovoi@uzsci.net

2010-07-15

A method of parametrically invariant quantities is developed for studying pseudorapidity configurations in nucleus-nucleus collisions involving a large number of secondary particles. In simple models where the spectrum of pseudorapidities depends on three parameters, the shape of the spectrum may differ strongly from the shape of pseudorapidity configurations in individual events. Pseudorapidity configurations in collisions between gold nuclei of energy 10.6 GeV per nucleon and track-emulsion nuclei are contrasted against those in random stars calculated theoretically. An investigation of pseudorapidity configurations in individual events is an efficient method for verifying theoretical models.

On the symmetries of the 12C nucleus

NASA Astrophysics Data System (ADS)

Cseh, J.; Trencsényi, R.

The consequences of some symmetries of the three-alpha system are discussed. In particular, the recent description of the low-energy spectrum of the 12C nucleus in terms of the algebraic cluster model (ACM) is compared to that of the multichannel dynamical symmetry (MUSY), which is the intersection of the shell and cluster models. The previous one applies interactions of a D3h geometric symmetry [D. J. Marin-Lambarri et al., Phys. Rev. Lett. 113 (2014) 012502], while the latter one has a U(3) dynamical symmetry. The available data is in line with both descriptions.

Shadowing in deep inelastic muon scattering from nuclear targets

NASA Astrophysics Data System (ADS)

Arneodo, M.; Arvidson, A.; Aubert, J. J.; Badelek, B.; Beaufays, J.; Bee, C. P.; Benchouk, C.; Berghoff, G.; Bird, I.; Blum, D.; Böhm, E.; De Bouard, X.; Brasse, F. W.; Braun, H.; Broll, C.; Brown, S.; Brück, H.; Brüll, A.; Calen, H.; Chima, J. S.; Ciborowski, J.; Clifft, R.; Coignet, G.; Combley, F.; Coughlan, J.; D'Agostini, G.; Dahlgren, S.; Dengler, F.; Derado, I.; Dreyer, T.; Drees, J.; Drobnitzki, M.; Düren, M.; Eckardt, V.; Edwards, A.; Edwards, M.; Ernst, T.; Eszes, G.; Favier, J.; Ferrero, M. I.; Figiel, J.; Foster, J.; Ftacnik, J.; Gabathuler, E.; Gajewski, J.; Gamet, R.; Geddes, N.; Grafström, P.; Gustafsson, L.; Haas, J.; Hagberg, E.; Hasert, F. J.; Hayman, P.; Heusse, P.; Jaffré, M.; Jacholkowska, A.; Janata, F.; Jancso, G.; Johnson, A. S.; Kabuss, E. M.; Kaiser, R.; Kellner, G.; Krüger, A.; Krüger, J.; Kullander, S.; Landgraf, U.; Lanske, D.; Loken, J.; Long, K.; Maire, M.; Malecki, P.; Manz, A.; Maselli, S.; Mohr, W.; Montanet, F.; Montgomery, H. E.; Nagy, E.; Nassalski, J.; Norton, P. R.; Oakham, F. G.; Osborne, A. M.; Pascaud, C.; Pawlik, B.; Payre, P.; Peroni, C.; Peschel, H.; Pessard, H.; Pettingale, J.; Pietrzyk, B.; Pietrzyk, U.; Pönsgen, B.; Pötsch, M.; Renton, P.; Ribarics, P.; Rith, K.; Rondio, E.; Sandacz, A.; Scheer, M.; Schlagböhmer, A.; Schiemann, H.; Schmitz, N.; Schneegans, M.; Scholz, M.; Schröder, T.; Schultze, K.; Seidel, A.; Sloan, T.; Stier, H. E.; Studt, M.; Taylor, G. N.; Thénard, J. M.; Thompson, J. C.; De La Torre, A.; Toth, J.; Urban, L.; Urban, L.; Wallucks, W.; Whalley, M.; Wheeler, S.; Williams, W. S. C.; Wimpenny, S. J.; Windmolders, R.; Wolf, G.; Ziemons, K.; European Muon Collaboration

1988-09-01

Results are presented on the ratio of the inelastic muon-nucleus cross section per nucleon for carbon and calcium relative to that for deuterium. The measurements were made in the kinematic range of low x (0.003-0.1) and low Q2 (0.3-3.2 GeV 2) at an incident muon energy of 280 GeV. The calcium to deuterium ratio shows a significant x dependence which is interpreted as a shadowing effect. No strong Q2 dependence is observed. This suggests that the effect is due at least partially to parton interactions within the nucleus.

The Low-Power Nucleus of PKS 1246-410 in the Centaurus Cluster

DOE Office of Scientific and Technical Information (OSTI.GOV)

Taylor, G.B.; /KIPAC, Menlo Park /NRAO, Socorro /New Mexico U.; Sanders, J.S.

2005-10-21

We present Chandra, Very Large Array (VLA), and Very Long Baseline Array (VLBA) observations of the nucleus of NGC 4696, a giant elliptical in the Centaurus cluster of galaxies. Like M87 in the Virgo cluster, PKS 1246-410 in the Centaurus cluster is a nearby example of a radio galaxy in a dense cluster environment. In analyzing the new X-ray data we have found a compact X-ray feature coincident with the optical and radio core. While nuclear emission from the X-ray source is expected, its luminosity is low, < 10{sup 40} erg s{sup -1}. We estimate the Bondi accretion radius tomore » be 30 pc and the accretion rate to be 0.01 M{sub {circle_dot}} y{sup -1} which under the canonical radiative efficiency of 10% would overproduce by 3.5 orders of magnitude the radiative luminosity. Much of this energy can be directed into the kinetic energy of the jet, which over time inflates the observed cavities seen in the thermal gas. The VLBA observations reveal a weak nucleus and a broad, one-sided jet extending over 25 parsecs in position angle -150 degrees. This jet is deflected on the kpc-scale to a more east-west orientation (position angle of -80 degrees).« less

Optical model with multiple band couplings using soft rotator structure

NASA Astrophysics Data System (ADS)

Martyanov, Dmitry; Soukhovitskii, Efrem; Capote, Roberto; Quesada, Jose Manuel; Chiba, Satoshi

2017-09-01

A new dispersive coupled-channel optical model (DCCOM) is derived that describes nucleon scattering on 238U and 232Th targets using a soft-rotator-model (SRM) description of the collective levels of the target nucleus. SRM Hamiltonian parameters are adjusted to the observed collective levels of the target nucleus. SRM nuclear wave functions (mixed in K quantum number) have been used to calculate coupling matrix elements of the generalized optical model. Five rotational bands are coupled: the ground-state band, β-, γ-, non-axial- bands, and a negative parity band. Such coupling scheme includes almost all levels below 1.2 MeV of excitation energy of targets. The "effective" deformations that define inter-band couplings are derived from SRM Hamiltonian parameters. Conservation of nuclear volume is enforced by introducing a monopolar deformed potential leading to additional couplings between rotational bands. The present DCCOM describes the total cross section differences between 238U and 232Th targets within experimental uncertainty from 50 keV up to 200 MeV of neutron incident energy. SRM couplings and volume conservation allow a precise calculation of the compound-nucleus (CN) formation cross sections, which is significantly different from the one calculated with rigid-rotor potentials with any number of coupled levels.

K-mixing in the doubly mid-shell nuclide 170Dy and the role of vibrational degeneracy

DOE PAGES

Soderstrom, P. -A.; Walker, P. M.; Wu, J.; ...

2016-10-04

Here, a detailed study of the structure of the doubly mid-shell nucleus 170 66Dy 104 has been carried out, following isomeric and β decay. We have measured the yrast band up to the spin-parity J π = 6 + state, the K = 2 γ -vibration band up to the 5 + state, a low-lying negative-parity band based on a 2¯ state that could be a candidate for the lowest energy octupole vibration state within this nucleus, and a candidate for the K π = 6+ two quasi-particle isomer. This state was determined to have an excitation energy of 1643.91(23)more » keV and a half life of 0.99(4) μs, with a reduced hindrance for its decay to the groundstate band an order of magnitude lower than predicted by N pN n systematics. This is interpreted as being due to γ -vibrational mixing from a near degeneracy of the isomer and the 6 + state of the γ band. Furthermore, the parent nucleus 170Tb has been determined to have a half-life of 0.91( +18 –13) s with a possible spin-parity of 2¯.« less

The nuclear superbubble of NGC 3079

NASA Technical Reports Server (NTRS)

Veilleux, S.; Cecil, G.; Bland-Hawthorn, J.; Tully, R. B.; Filippenko, A. V.; Sargent, W. L. W.

1994-01-01

We have used the Hawaii Imaging Fabry-Perot Interferometer (HIFI) at the CFH 3.6 m telescope to map H-alpha + (N II) lambda-lambda 6548, 6583 emission-line profiles across the entire edge-on, nearby SBc galaxy NGC 3079, with resolution 70 km/s and subarcsecond sampling. Blue and red long-slit spectra were obtained with the Double Spectrograph on the Palomar 5 meter telescope to provide additional emission-line diagnostics. A spectacular, line emitting bubble of diameter 13 sec (approximately 1.1 kpc) is observed immediately east of the nucleus. Its unusual gaseous excitation (e.g., (N II) lambda(6583)/H-alpha greater than 1) suggests that shocks are important. Extremely violent gas motions that range over 2000 km/s are detected across the bubble and diametrically opposite on the west side of the nucleus. Nonrotational motions are also found in the inner galaxy disk. The superbubble of NGC 3079 is the most powerful example known of a wind-blown bubble, and an excellent laboratory to study wind dynamics. The dimensions and energies of the bubble imply that is likely to be in the blowout phase and partially ruptured. The predicted rate of kinetic energy output from the central starburst appears sufficient to power most of this outflow. It is possible that a central active galactic nucleus also contributes to the outflow.

Brain-mediated dysregulation of the bone marrow activity in angiotensin II-induced hypertension.

PubMed

Jun, Joo Yun; Zubcevic, Jasenka; Qi, Yanfei; Afzal, Aqeela; Carvajal, Jessica Marulanda; Thinschmidt, Jeffrey S; Grant, Maria B; Mocco, J; Raizada, Mohan K

2012-11-01

Oxidative stress in the brain is implicated in increased sympathetic drive, inflammatory status, and vascular dysfunctions, associated with development and establishment of hypertension. However, little is known about the mechanism of this impaired brain-vascular communication. Here, we tested the hypothesis that increased oxidative stress in the brain cardioregulatory areas, such as the paraventricular nucleus of the hypothalamus, is driven by mitochondrial reactive oxygen species and leads to increased inflammatory cells (ICs) and decreased/dysfunctional endothelial progenitor cells (EPCs), thereby compromising vasculature repair and accelerating hypertension. Chronic angiotensin II infusion resulted in elevated blood pressure and sympathetic vasomotor drive, decreased spontaneous baroreflex gain, and increased microglia activation in the paraventricular nucleus. This was associated with 46% decrease in bone marrow (BM)-derived EPCs and 250% increase in BM ICs, resulting in 5-fold decrease of EPC/IC ratio in the BM. Treatment with mitochondrial-targeted antioxidant, a scavenger of mitochondrial O(2)(-·), intracerebroventricularly but not subcutaneously attenuated angiotensin II-induced hypertension, decreased activation of microglia in the paraventricular nucleus, and normalized EPCs/ICs. This functional communication between the brain and BM was confirmed by retrograde neuronal labeling from the BM with green fluorescent protein-tagged pseudorabies virus. Administration of green fluorescent protein-tagged pseudorabies virus into the BM resulted in predominant labeling of paraventricular nucleus neurons within 3 days, with some fluorescence in the nucleus tractus solitarius, the rostral ventrolateral medulla, and subfornical organ. Taken together, these data demonstrate that inhibition of mitochondrial reactive oxygen species attenuates angiotensin II-induced hypertension and corrects the imbalance in EPCs/ICs in the BM. They suggest that an imbalance in vascular reparative and ICs may perpetuate vascular pathophysiology in this model of hypertension.

Determination of the real part of the η'-Nb optical potential

NASA Astrophysics Data System (ADS)

Nanova, M.; Friedrich, S.; Metag, V.; Paryev, E. Ya.; Afzal, F. N.; Bayadilov, D.; Beck, R.; Becker, M.; Böse, S.; Brinkmann, K.-T.; Crede, V.; Elsner, D.; Frommberger, F.; Grüner, M.; Gutz, E.; Hammann, Ch.; Hannappel, J.; Hartmann, J.; Hillert, W.; Hoffmeister, P.; Honisch, Ch.; Jude, T.; Kalischewski, F.; Keshelashvili, I.; Klein, F.; Koop, K.; Krusche, B.; Lang, M.; Makonyi, K.; Messi, F.; Müller, J.; Müllers, J.; Piontek, D.-M.; Rostomyan, T.; Schaab, D.; Schmidt, C.; Schmieden, H.; Schmitz, R.; Seifen, T.; Sowa, C.; Spieker, K.; Thiel, A.; Thoma, U.; Triffterer, T.; Urban, M.; van Pee, H.; Walther, D.; Wendel, C.; Werthmüller, D.; Wiedner, U.; Wilson, A.; Witthauer, L.; Wunderlich, Y.; Zaunick, H.-G.; Cbelsa/Taps Collaboration

2016-08-01

The excitation function and momentum distribution of η' mesons have been measured in photoproduction off 93Nb in the energy range of 1.2-2.9 GeV. The experiment has been performed with the combined Crystal Barrel and MiniTAPS detector system, using tagged photon beams from the ELSA electron accelerator. Information on the sign and magnitude of the real part of the η'-Nb potential has been extracted from a comparison of the data with model calculations. An attractive potential of -(41 ±10 (stat )±15 (syst )) MeV depth at normal nuclear matter density is deduced within model uncertainties. This value is consistent with the potential depth of -(37 ±10 (stat )±10 (syst )) MeV obtained in an earlier measurement for a light nucleus (carbon). This relatively shallow η'-nucleus potential will make the search for η'-nucleus bound states more difficult.

Development of New High Resolution Neutron Detector

NASA Astrophysics Data System (ADS)

Mostella, L. D., III; Rajabali, M.; Loureiro, D. P.; Grzywacz, R.

2017-09-01

Beta-delayed neutron emission is a prevalent form of decay for neutron-rich nuclei. This occurs when an unstable nucleus undergoes beta decay, but produces a daughter nucleus in an excited state above the neutron separation energy. The daughter nucleus then de-excites by ejecting one or more neutrons. We wish to map the states from which these nuclei decay via neutron spectroscopy using NEXT, a new high resolution neutron detector. NEXT utilizes silicon photomultipliers and 6 mm thick pulse-shape discriminating plastic scintillators, allowing for smaller and more compact modular geometries in the NEXT array. Timing measurements for the detector were performed and a resolution of 893 ps (FWHM) has been achieved so far. Aspects of the detector that were investigated and will be presented here include scintillator geometry, wrapping materials, fitting functions for the digitized signals, and electronic components coupled to the silicon photomultipliers for signal shaping.

Charge radius of the 13N* proton halo nucleus with Halo Effective Field Theory

NASA Astrophysics Data System (ADS)

Mosavi Khansari, M.; Khalili, H.; Sadeghi, H.

2018-02-01

We evaluated the charge radius of the first excited state of 13N with halo Effective Field Theory (hEFT) at the low energies. The halo effective field theory without pion is used to examine the halo nucleus bound state with a large S-wave scattering length. We built Lagrangian from the effective core and the valence proton of the fields and obtained the charge form factor at Leading-Order (LO). The charge radius at leading order for the first excited state of the proton halo nucleus, 13N, has been estimated as rc = 2.52 fm. This result is without any finite-size contributions included from the core and the proton. If we consider the contributions of the charge radius of the proton and the core, the result will be [rC]13N* = 5.85 fm.

Coulomb Excitation of the N = 50 nucleus 80Zn

NASA Astrophysics Data System (ADS)

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

2008-05-01

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

Looking for the Phase Transition—Recent NA61/SHINE Results

NASA Astrophysics Data System (ADS)

Turko, Ludwik

2018-03-01

The fixed-target NA61/SHINE experiment (SPS CERN) looks for the critical point of strongly interacting matter and the properties of the onset of deconfinement. It is a two dimensional scan of measurements of particle spectra and fluctuations in proton-proton, proton-nucleus and nucleus-nucleus interactions as a function of collision energy and system size, corresponding to a two dimensional phase diagram (temperature T - baryonic chemical potential $\\mu_B$). New NA61/SHINE results are presented here, such as transverse momentum and multiplicity fluctuations in Ar+Sc collisions compared to NA61/SHINE p+p and Be+Be data, as well as to earlier NA49 A+A results. Recently, a preliminary signature for the new size dependent effect - rapid changes in system size dependence was observed in NA61-SHINE data, labeled as percolation threshold or onset of fireball. This would be closely related to the vicinity of the hadronic phase transition region.