637 research outputs found
Thermo-Hysteresis Phenomenon of the Electrical Resistivity in Fe_2Ti Suggesting Its Martensitic Transformation
Some indirect evidence is found of the occurrence of a martensitic transformation below room temperature in the Laves phase compounds in the Fe-Ti alloy system. The detailed measurements of the electrical resistivity from 4.2 to 1200°K show a large thermo-hysteresis, suggesting that the low temperature transformation develops just below room temperature and the high temperature one begins at about 560°K in the stoichiometric compound. Although the X-ray powder photographs show no clear evidence of a new phase, it may be interpreted that the new phase consists of a very small volume with a fine structure
A likely detection of a local interplanetary dust cloud passing near the Earth in the AKARI mid-infrared all-sky map
Context. We are creating the AKARI mid-infrared all-sky diffuse maps. Through
a foreground removal of the zodiacal emission, we serendipitously detected a
bright residual component whose angular size is about 50 x 20 deg. at a
wavelength of 9 micron. Aims. We investigate the origin and the physical
properties of the residual component. Methods. We measured the surface
brightness of the residual component in the AKARI mid-infrared all-sky maps.
Results. The residual component was significantly detected only in 2007
January, even though the same region was observed in 2006 July and 2007 July,
which shows that it is not due to the Galactic emission. We suggest that this
may be a small cloud passing near the Earth. By comparing the observed
intensity ratio of I_9um/I_18um with the expected intensity ratio assuming
thermal equilibrium of dust grains at 1 AU for various dust compositions and
sizes, we find that dust grains in the moving cloud are likely to be much
smaller than typical grains that produce the bulk of the zodiacal light.
Conclusions. Considering the observed date and position, it is likely that it
originates in the solar coronal mass ejection (CME) which took place on 2007
January 25.Comment: 5 pages, 4 figures, accepted by Astronomy and Astrophysic
Mohawk promotes the maintenance and regeneration of the outer annulus fibrosus of intervertebral discs.
The main pathogenesis of intervertebral disc (IVD) herniation involves disruption of the annulus fibrosus (AF) caused by ageing or excessive mechanical stress and the resulting prolapse of the nucleus pulposus. Owing to the avascular nature of the IVD and lack of understanding the mechanisms that maintain the IVD, current therapies do not lead to tissue regeneration. Here we show that homeobox protein Mohawk (Mkx) is a key transcription factor that regulates AF development, maintenance and regeneration. Mkx is mainly expressed in the outer AF (OAF) of humans and mice. In Mkx(-/-) mice, the OAF displays a deficiency of multiple tendon/ligament-related genes, a smaller OAF collagen fibril diameter and a more rapid progression of IVD degeneration compared with the wild type. Mesenchymal stem cells overexpressing Mkx promote functional AF regeneration in a mouse AF defect model, with abundant collagen fibril formation. Our results indicate a therapeutic strategy for AF regeneration
Detection of human herpesviruses in the cerebrospinal fluid from patients diagnosed with or suspected of having progressive multifocal leukoencephalopathy
Kondo Effect in the Transport Properties of the CsCl-Type Compounds Fe_<1-x>Ti_<1+x> : II. Magnetic Scattering Center due to Atomic Disordering(Physics)
Neutron diffraction measurements were made at room temperature for the CsCl-type compounds, Fe_Ti_, in order to confirm the origins of the anomalous transport phenomena in the titanium-rich compositions and the superparamagnetism near the stoichiometric one. On the basis of those results, it could be concluded that the former behaviour is due to the Kondo effect, originating in a magnetic cluster of nine iron atoms with a concentration of about 10^, produced by the atomic disorder. The composition dependence of the residual resistivity also seems to be explainable from this point of view
Gravitational Instantons and Moduli Spaces of Topological 2-form Gravity
A topological version of four-dimensional (Euclidean) Einstein gravity which
we propose regards anti-self-dual 2-forms and an anti-self-dual part of the
frame connections as fundamental fields. The theory describes the moduli spaces
of conformally self-dual Einstein manifolds for the non-zero cosmological
constant case and Einstein-Kahlerian manifold with the vanishing real first
Chern class for the zero cosmological constant. In the non-zero cosmological
constant case, we evaluate the index of the elliptic complex associated with
the moduli space and calculate the partition function. We also clarify the
moduli space and its dimension for the zero cosmological constant case which
are related to the Plebansky's heavenly equations.Comment: 36pages, LaTex, TIT/HEP-247/COSMO-4
Local virial relation for self-gravitating system
We demonstrate that the quasi-equilibrium state in self-gravitating -body
system after cold collapse are uniquely characterized by the local virial
relation using numerical simulations. Conversely assuming the constant local
virial ratio and Jeans equation for spherically steady state system, we
investigate the full solution space of the problem under the constant
anisotropy parameter and obtain some relevant solutions. Especially, the local
virial relation always provides a solution which has a power law density
profile in both the asymptotic regions and . This type of
solutions observed commonly in many numerical simulations. Only the anisotropic
velocity dispersion controls this asymptotic behavior of density profile.Comment: 9 pages, 15 eps figures, RevTex, submitted to PR
Half-Metallic Ferrimagnetism in Mn_2VAl
We show that Mn_2VAl is a compound for which the generalized gradient
approximation (GGA) to the exchange-correlation functional in density
functional theory makes a qualitative change in predicted behavior compared to
the usual local density approximation (LDA). Application of GGA leads to
prediction of Mn_2VAl being a half-metallic ferrimagnet, with the minority
channel being the conducting one. The electronic and magnetic structure is
analyzed and contrasted with the isostructural enhanced semimetal Fe_2VAl.Comment: 5 pages, Latex, 6 postscript figures. Description and figures of the
(minority) Fermi surfaces have been adde
Transverse Plane Tendon and Median Nerve Motion in the Carpal Tunnel: Ultrasound Comparison of Carpal Tunnel Syndrome Patients and Healthy Volunteers
The median nerve and flexor tendons are known to translate transversely in the carpal tunnel. The purpose of this study was to investigate these motions in differential finger motion using ultrasound, and to compare them in healthy people and carpal tunnel syndrome patients.Transverse ultrasounds clips were taken during fist, index finger, middle finger and thumb flexion in 29 healthy normal subjects and 29 CTS patients. Displacement in palmar-dorsal and radial-ulnar direction was calculated using Analyze software. Additionally, the distance between the median nerve and the tendons was calculated.We found a changed motion pattern of the median nerve in middle finger, index finger and thumb motion between normal subjects and CTS patients (p<0.05). Also, we found a changed motion direction in CTS patients of the FDS III tendon in fist and middle finger motion, and of the FDS II and flexor pollicis longus tendon in index finger and thumb motion, respectively (p<0.05). The distance between the median nerve and the FDS II or FPL tendon is significantly greater in patients than in healthy volunteers for index finger and thumb motion, respectively (p<0.05).Our results suggest a changed motion pattern of the median nerve and several tendons in carpal tunnel syndrome patients compared to normal subjects. Such motion patterns may be useful in distinguishing affected from unaffected individuals, and in studies of the pathomechanics of carpal tunnel syndrome
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