204 research outputs found
Preparation of metal nano particles using electrochemical deposition : Pt nano patterned electrodes
A novel alveolar epithelial cell sheet fabricated under feeder-free conditions for potential use in pulmonary regenerative therapy
Bioartificial pulsatile cuffs fabricated from human induced pluripotent stem cell-derived cardiomyocytes using a pre-vascularization technique
NMR and mutational identification of the collagen-binding site of the chaperone Hsp47.
Heat shock protein 47 (Hsp47) acts as a client-specific chaperone for collagen and plays a vital role in collagen maturation and the consequent embryonic development. In addition, this protein can be a potential target for the treatment of fibrosis. Despite its physiological and pathological importance, little is currently known about the collagen-binding mode of Hsp47 from a structural aspect. Here, we describe an NMR study that was conducted to identify the collagen-binding site of Hsp47. We used chicken Hsp47, which has higher solubility than its human counterpart, and applied a selective (15)N-labeling method targeting its tryptophan and histidine residues. Spectral assignments were made based on site-directed mutagenesis of the individual residues. By inspecting the spectral changes that were observed upon interaction with a trimeric collagen peptide and the mutational data, we successfully mapped the collagen-binding site in the B/C β-barrel domain and a nearby loop in a 3D-homology model based upon a serpin fold. This conclusion was confirmed by mutational analysis. Our findings provide a molecular basis for the design of compounds that target the interaction between Hsp47 and procollagen as therapeutics for fibrotic diseases
Prospective effects of free radical scavenger edaravone against xanthine oxidase-mediated permeability increases in human intestinal epithelial cell monolayer
Pressure-induced structural phase transition and new superconducting phase in UTe2
We report on the crystal structure and electronic properties of the heavy
fermion superconductor UTe2 at high pressure up to 11 GPa, as investigated by
X-ray diffraction and electrical resistivity experiments. The X-ray diffraction
measurements under high pressure using a synchrotron light source reveal
anisotropic linear compressibility of the unit cell up to 3.5 GPa, while a
pressure-induced structural phase transition is observed above 3.5-4GPa at room
temperature, where the body-centered orthorhombic crystal structure with the
space group Immm changes into a body-centered tetragonal structure with the
space group I4/mmm. The molar volume drops abruptly at the critical pressure,
while the distance between the first-nearest neighbor of U atoms increases,
implying a switch from the heavy electronic states to the weakly correlated
electronic states. Surprisingly, a new superconducting phase at pressures
higher than 7 GPa was detected at Tsc above 2K with a relatively low
upper-critical field, Hc2(0). The resistivity above 3.5GPa, thus, in the
high-pressure tetragonal phase, shows a large drop below 230 K, which may also
be related to a considerable change from the heavy electronic states to the
weakly correlated electronic states.Comment: 11 pages, 9 figure
First Observation of de Haas-van Alphen Effect and Fermi Surfaces in Unconventional Superconductor UTe2
We report the first observation of the de Haas-van Alphen (dHvA) effect in
the novel spin-triplet superconductor UTe2 using high quality single crystals
with the high residual resistivity ratio (RRR) over 200. The dHvA frequencies,
named alpha and beta, are detected for the field directions between c and
a-axes. The frequency of branch beta increases rapidly with the field angle
tilted from c to a-axis, while branch alpha splits, owing to the maximal and
minimal cross-sectional areas from the same Fermi surface. Both dHvA branches,
alpha and beta reveal two kinds of cylindrical Fermi surfaces with a strong
corrugation at least for branch alpha. The angular dependence of the dHvA
frequencies is in very good agreement with that calculated by the generalized
gradient approximation (GGA) method taking into account the on-site Coulomb
repulsion of U = 2 eV, indicating the main Fermi surfaces are experimentally
detected. The detected cyclotron effective masses are large in the range from
32 to 57 m0 . They are approximately 10-20 times lager than the corresponding
band masses, consistent with the mass enhancement obtained from the Sommerfeld
coefficient and the calculated density of states at the Fermi level. The local
density approximation (LDA) calculations of ThTe2 assuming U4+ with the 5f^2
localized model are in less agreement with our experimental results, in spite
of the prediction for two cylindrical Fermi surfaces, suggesting a mixed
valence states of U4+ and U3+ in UTe2.Comment: 7 pages, 8 figures, submitted to J. Phys. Soc. Jp
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