638 research outputs found
DRG-targeted helper-dependent adenoviruses mediate selective gene delivery for therapeutic rescue of sensory neuronopathies in mice
Dorsal root ganglion (DRG) neuron dysfunction occurs in a variety of sensory neuronopathies for which there are currently no satisfactory treatments. Here we describe the development of a strategy to target therapeutic genes to DRG neurons for the treatment of these disorders. We genetically modified an adenovirus (Ad) to generate a helper virus (HV) that was detargeted for native adenoviral tropism and contained DRG homing peptides in the adenoviral capsid fiber protein; we used this HV to generate DRG-targeted helper-dependent Ad (HDAd). In mice, intrathecal injection of this HDAd produced a 100-fold higher transduction of DRG neurons and a markedly attenuated inflammatory response compared with unmodified HDAd. We also injected HDAd encoding the β subunit of β-hexosaminidase (Hexb) into Hexb-deficient mice, a model of the neuronopathy Sandhoff disease. Delivery of the DRG-targeted HDAd reinstated neuron-specific Hexb production, reversed gangliosidosis, and ameliorated peripheral sensory dysfunction. The development of DRG neuron–targeted HDAd with proven efficacy in a preclinical model may have implications for the treatment of sensory neuronopathies of diverse etiologies
Precessional motion of a vortex in a finite-temperature Bose-Einstein condensate
We study the precessing motion of a vortex in a Bose-Einstein condensate of
atomic gases. In addition to the former zero-temperature studies, finite
temperature systems are treated within the Popov and semiclassical
approximations. Precessing vortices are discussed utilizing the rotating frame
of reference. The relationship between the sign of the lowest excitation energy
and the direction of precession is discussed in detail.Comment: 6 pages, 9 figures. More discussion in Sec.III. Reference is update
First-principles study on scanning tunneling microscopy images of hydrogen-terminated Si(110) surfaces
Scanning tunneling microscopy images of hydrogen-terminated Si(110) surfaces
are studied using first-principles calculations. Our results show that the
calculated filled-state images and local density of states are consistent with
recent experimental results, and the empty-state images appear significantly
different from the filled-state ones. To elucidate the origin of this
difference, we examined in detail the local density of states, which affects
the images, and found that the bonding and antibonding states of surface
silicon atoms largely affect the difference between the filled- and empty-state
images.Comment: 4 pages, and 4 figure
A Molecular Line Observation toward Massive Clumps Associated with Infrared Dark Clouds
We have surveyed the N2H+ J=1-0, HC3N J=5-4, CCS J_N=4_3-3_2, NH3 (J, K) =
(1, 1), (2, 2), (3, 3), and CH3OH J=7-6 lines toward the 55 massive clumps
associated with infrared dark clouds by using the Nobeyama Radio Observatory 45
m telescope and the Atacama Submillimeter Telescope Experiment 10 m telescope.
The N2H+, HC3N, and NH3 lines are detected toward most of the objects. On the
other hand, the CCS emission is detected toward none of the objects. The
[CCS]/[N2H+] ratios are found to be mostly lower than unity even in the Spitzer
24 micron dark objects. This suggests that most of the massive clumps are
chemically more evolved than the low-mass starless cores. The CH3OH emission is
detected toward 18 out of 55 objects. All the CH3OH-detected objects are
associated with the Spitzer 24 micron sources, suggesting that star formation
has already started in all the CH3OH-detected objects. The velocity widths of
the CH3OH J_K=7_0-6_0 A+ and 7_{-1}-6_{-1} E lines are broader than those of
N2H+ J=1-0. The CH3OH J_K=7_0-6_0 A+ and 7_{-1}-6_{-1} E lines tend to have
broader linewidth in the MSX dark objects than in the others, the former being
younger or less luminous than the latter. The origin of the broad emission is
discussed in terms of the interaction between an outflow and an ambient cloud.Comment: Accepted to Ap
Mapping Observations of DNC and HN^13C in Dark Cloud Cores
We present results of mapping observations of the DNC, HN^13C, and H^13CO^+
lines (J=1-0) toward 4 nearby dark cloud cores, TMC-1, L1512, L1544, and L63,
along with observations of the DNC and HN^13C lines (J=2-1) toward selected
positions. By use of statistical equilibrium calculations based on the LVG
model, the H_2 densities are derived to be (1.4-5.5)*10^5 cm^-3, and the
[DNC]/[HN^13C] ratios are derived to be 1.25-5.44 with a typical uncertainty by
a factor of 2. The observed [DNC]/[HNC] ratios range from 0.02 to 0.09,
assuming the [^12C]/[^13C] ratio of 60. Distributions of DNC and HN^13C are
generally similar to each other, whereas the distribution of H^13CO^+ is more
extended than those of DNC and HN^13C, indicating that they reside in an inner
part of the cores than HCO^+. The [DNC]/[HN^13C] ratio is rather constant
within each core, although a small systematic gradients are observed in TMC-1
and L63. Particularly, no such systematic gradient is found in L1512 and L1544,
where a significant effect of depletion of molecules is reported toward the
central part of the cores. This suggests that the [DNC]/[HNC] ratio would not
be very sensitive to depletion factor, unlike the [DCO^+]/[HCO^+] ratio. On the
other hand, the core to core variation of the [DNC]/[HNC] ratio, which range an
order of magnitude, is more remarkable than the variation within each core.
These results are interpreted qualitatively by a combination of three competing
time-dependent processes; gas-phase deuterium fractionation, depletion of
molecules onto grain surface, and dynamical evolution of a core.Comment: 22 pages, 8 EPS figures, aasLaTex 5.0, accepted to The Astrophysical
Journa
Molecular Line Observations of a Carbon-Chain-Rich Core L492
We report on molecular abundances and distributions in a starless dense core
L492. We have found that the abundances of carbon-chain molecules such as CCS,
CS, HCN, HCN, and HCN are comparable to those in
chemically young dark cloud cores called "carbon-chain--producing regions",
such as L1495B, L1521B, L1521E, and TMC-1. This is the first dark cloud core
with extremely rich in carbon-chain-molecules that is found outside the Taurus
region. In addition, the deuterium fractionation ratios of DNC/HNC and
DCO/HCO are also comparable to those in carbon-chain--producing
regions, being significantly lower than those in the evolved prestellar cores
such as L1498 and L1544. On the other hand, the abundances of NH and
NH are systematically higher than those in carbon-chain--producing
regions. Our mapping observations reveal that the central hole of molecular
distributions, which were reported for CCS and CS in evolved prestellar
cores is not significant in L492, indicating that the depletion factor of
molecules is not very high. Furthermore, L492 is dynamically more evolved than
carbon-chain--producing regions, and the protostellar collapse has started like
L1498 and L1544. Therefore, it is likely that the chemical and dynamical
evolutionary stage of L492 is intermediate between carbon-chain--producing
regions (L1495B, L1521B, L1521E, and TMC-1) and evolved prestellar cores (L1498
and L1544).Comment: 26 pages, 8 figures, accepted for publication in The Astrophysical
Journal (Preprint with high resolution figures will be available at
http://www.nro.nao.ac.jp/library/report/list.html
Spin domain formation in spinor Bose-Einstein condensation
The spatial structure of the spinor Bose-Einstein condensates with the spin
degrees of freedom is analyzed based on the generalized Gross-Pitaevskii
equation (GP) in the light of the present spin domain experiment on m_F=\pm 1,
and 0 of the hyperfine state F=1 of ^{23}Na atom gases. The GP solutions in
three- and one-spatial dimensional cases reproduce the observed spin domain
structures, revealing the length scale associated with the existence of the
weak interaction of the spin-spin channel, other than the ordinary coherence
length related to the density-density channel. The obtained domain structure in
GP is compared with the result in Thomas-Fermi approximation. The former
solution is found to better describe the observed features than the latter.Comment: 9 pages, 14 figure
Estimation of Power Balance in Steady State LHCD Discharges on TRIAM-1M
On TRIAM-1M, a long duration discharge for more than 5 h was achieved
successfully by fully non-inductive lower hybrid current drive. Heat load
distribution to the plasma facing components (PFCs) in the 5 h discharge was
investigated by using calorimetric measurements. The injected RF power was
coincident with the total amount of heat load to PFCs estimated by calorimetric
measurement. The power balance including the portion of direct loss power of
fast electron, heat flux due to the charge exchange process was able to be
estimated in this long duration discharge.Comment: 12th International Congress on Plasma Physics, 25-29 October 2004,
Nice (France
First-Principles Study on Peierls Instability in Infinite Single-Row Al Wires
We present the relation between the atomic and spin-electronic structures of
infinite single-row atomic wires made of Al atoms during their elongation using
first-principles molecular-dynamics simulations. Our study reveals that the
Peierls transition indeed occurs in the wire with magnetic ordering: it
ruptures to form a trimerized structure with antiferromagnetic ordering and
changes from a conductor to an insulator just before forming a linear wire of
equally-spaced atoms. The formation of the trimerized wire is discussed in
terms of the behavior of the -symmetry bands of the Al wire.Comment: 10 pages, 4 figure
First-principles study of electron transport through cages
Electron transport properties of C molecules suspended between gold
electrodes are investigated using first-principles calculations. Our study
reveals that the conductances are quite sensitive to the number of C
molecules between electrodes: the conductances of C monomers are near 1
G, while those of dimers are markedly smaller, since incident electrons
easily pass the C molecules and are predominantly scattered at the
C-C junctions. Moreover, we find both channel currents locally
circulating the outermost carbon atoms.Comment: 8 pages and 3 figure
- …