5,291 research outputs found
Life fingerprints of nuclear reactions in the body of animals
Nuclear reactions are a very important natural phenomenon in the universe. On the earth, cosmic rays constantly cause nuclear reactions. High energy beams created by medical devices also induce nuclear reactions in the human body. The biological role of these nuclear reactions is unknown. Here we show that the in vivo biological systems are exquisite and sophisticated by nature in influence on nuclear reactions and in resistance to radical damage in the body of live animals. In this study, photonuclear reactions in the body of live or dead animals were induced with 50-MeV irradiation. Tissue nuclear reactions were detected by positron emission tomography (PET) imaging of the induced beta+ activity. We found the unique tissue "fingerprints" of beta+ (the tremendous difference in beta+ activities and tissue distribution patterns among the individuals) are imprinted in all live animals. Within any individual, the tissue "fingerprints" of 15O and 11C are also very different. When the animal dies, the tissue "fingerprints" are lost. The biochemical, rather than physical, mechanisms could play a critical role in the phenomenon of tissue "fingerprints". Radiolytic radical attack caused millions-fold increases in 15O and 11C activities via different biochemical mechanisms, i.e. radical-mediated hydroxylation and peroxidation respectively, and more importantly the bio-molecular functions (such as the chemical reactivity and the solvent accessibility to radicals). In practice biologically for example, radical attack can therefore be imaged in vivo in live animals and humans using PET for life science research, disease prevention, and personalized radiation therapy based on an individual's bio-molecular response to ionizing radiation
FAST polarization mapping of the SNR VRO 42.05.01
We have obtained the polarization data cube of the VRO 42.05.01 supernova
remnant at 1240 MHz using the Five-hundred-meter Aperture Spherical radio
Telescope (FAST). Three-dimensional Faraday Synthesis is applied to the FAST
data to derive the Faraday depth spectrum. The peak Faraday depth map shows a
large area of enhanced foreground RM of ~60 rad m-2 extending along the
remnant's "wing" section, which coincides with a large-scale HI shell at -20
km/s. The two depolarization patches within the "wing" region with RM of 97 rad
m-2 and 55 rad m-2 coincide with two HI structures in the HI shell. Faraday
screen model fitting on the Canadian Galactic Plane Survey (CGPS) 1420 MHz
full-scale polarization data reveals a distance of 0.7-0.8d_{SNR} in front of
the SNR with enhanced regular magnetic field there. The highly piled-up
magnetic field indicates that the HI shell at -20 km/s could originate from an
old evolved SNR.Comment: 9 pages, 8 figures, accepted by Ap
Improvement of Sciatic Nerve Regeneration Using Laminin-Binding Human NGF-Ξ²
Sciatic nerve injuries often cause partial or total loss of motor, sensory and autonomic functions due to the axon discontinuity, degeneration, and eventual death which finally result in substantial functional loss and decreased quality of life. Nerve growth factor (NGF) plays a critical role in peripheral nerve regeneration. However, the lack of efficient NGF delivery approach limits its clinical applications. We reported here by fusing with the N-terminal domain of agrin (NtA), NGF-Ξ² could target to nerve cells and improve nerve regeneration. was also measured. Using the rat sciatic nerve crush injury model, the nerve repair and functional restoration by utilizing LBD-NGF were tested.. In the rat sciatic nerve crush injury model, we found that LBD-NGF could be retained and concentrated at the nerve injury sites to promote nerve repair and enhance functional restoration following nerve damages.Fused with NtA, NGF-Ξ² could bind to laminin specifically. Since laminin is the major component of nerve extracellular matrix, laminin binding NGF could target to nerve cells and improve the repair of peripheral nerve injuries
Superfluidity of Bosons in Kagome Lattices with Frustration
In this letter we consider spinless bosons in a Kagome lattice with
nearest-neighbor hopping and on-site interaction, and the sign of hopping is
inverted by insetting a {\pi} flux in each triangle of Kagome lattice so that
the lowest single particle band is perfectly flat. We show that in the high
density limit, despite of the infinite degeneracy of the single particle ground
states, interaction will select out the Bloch state at the K point of Brillouin
zone for boson condensation at the lowest temperature. As temperature
increases, the single boson superfluid order can be easily destroyed, while an
exotic triple-boson paired superfluid order will remain. We establish that this
trion superfluid exists in a broad temperature regime until the temperature is
increased to the same order of hopping and then the system turns into normal
phases. Finally we show that time of flight measurement of momentum
distribution and its noise correlation can be used to distinguish these three
phases.Comment: 4 pages + references, 5 figure
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