127 research outputs found
Epitaxially stabilized iridium spinel oxide without cations in the tetrahedral site
Single-crystalline thin film of an iridium dioxide polymorph Ir2O4 has been
fabricated by the pulsed laser deposition of LixIr2O4 precursor and the
subsequent Li-deintercalation using soft chemistry. Ir2O4 crystallizes in a
spinel (AB2O4) without A cations in the tetrahedral site, which is
isostructural to lambda-MnO2. Ir ions form a pyrochlore sublattice, which is
known to give rise to a strong geometrical frustration. This Ir spinel was
found to be a narrow gap insulator, in remarkable contrast to the metallic
ground state of rutile-type IrO2. We argue that an interplay of strong
spin-orbit coupling and a Coulomb repulsion gives rise to an insulating ground
state as in a layered perovskite Sr2IrO4.Comment: 9 pages, 3 figure
Assessment of intraoral mucosal pain induced by the application of capsaicin
Objective
To develop an objective method for assessing nociceptive behaviour in an animal model of capsaicin-induced intraoral pain. Changes in nociceptive responses were also examined after injury to the inferior alveolar nerve (IAN).
Design
Nociceptive responses evoked by the intraoral application of various doses of capsaicin were analyzed in lightly anaesthetized rats. The number of c-Fos protein-like immunoreactive (Fos-LI) neurons in the medullary dorsal horn (MDH) induced by the intraoral application of capsaicin was measured. Behavioural and c-Fos responses were also examined 14 days after injury to the IAN.
Results
Larger doses of intraoral capsaicin (1, 10 and 100 μg) induced vigorous licking behaviour and c-Fos response in the MDH in a reproducible manner. The magnitudes of both behavioural activity and the c-Fos response from the 10 and 100 μg doses of capsaicin were significantly greater than that by the 1 μg dose. Injury to the IAN exaggerated the behavioural and c-Fos responses evoked by intraoral capsaicin.
Conclusions
The intraoral application of capsaicin is a valid and reliable method for studying intraoral pain and hyperalgesia following nerve injury
The HPB-AML-I cell line possesses the properties of mesenchymal stem cells
<p>Abstract</p> <p>Background</p> <p>In spite of its establishment from the peripheral blood of a case with acute myeloid leukemia (AML)-M1, HPB-AML-I shows plastic adherence with spindle-like morphology. In addition, lipid droplets can be induced in HPB-AML-I cells by methylisobutylxanthine, hydrocortisone, and indomethacin. These findings suggest that HPB-AML-I is similar to mesenchymal stem cells (MSCs) or mesenchymal stromal cells rather than to hematopoietic cells.</p> <p>Methods</p> <p>To examine this possibility, we characterized HPB-AML-I by performing cytochemical, cytogenetic, and phenotypic analyses, induction of differentiation toward mesenchymal lineage cells, and mixed lymphocyte culture analysis.</p> <p>Results</p> <p>HPB-AML-I proved to be negative for myeloperoxidase, while surface antigen analysis disclosed that it was positive for MSC-related antigens, such as CD29, CD44, CD55, CD59, and CD73, but not for CD14, CD19, CD34, CD45, CD90, CD105, CD117, and HLA-DR. Karyotypic analysis showed the presence of complicated abnormalities, but no reciprocal translocations typically detected in AML cases. Following the induction of differentiation toward adipocytes, chondrocytes, and osteocytes, HPB-AML-I cells showed, in conjunction with extracellular matrix formation, lipid accumulation, proteoglycan synthesis, and alkaline phosphatase expression. Mixed lymphocyte culture demonstrated that CD3<sup>+ </sup>T-cell proliferation was suppressed in the presence of HPB-AML-I cells.</p> <p>Conclusions</p> <p>We conclude that HPB-AML-I cells appear to be unique neoplastic cells, which may be derived from MSCs, but are not hematopoietic progenitor cells.</p
Heat Flux of a Transferred Arc Driven by a Transverse Magnetic Field
Theoretical consideration of a magnetically driven arc was performed to elucidate the variation of heat flux with an imposed DC magnetic field. Experiments were conducted to confirm the validity of the theoretical model. The heat flux decreased concomitantly with increased imposed magnetic flux density. Theoretical predictions agreed with experimental results
Exact Description of D-branes via Tachyon Condensation
We examine the fluctuations around a Dp-brane solution in an unstable D-brane
system using boundary states and also boundary string field theory. We show
that the fluctuations correctly reproduce the fields on the Dp-brane. Plugging
these into the action of the unstable D-brane system, we recover not only the
tension and RR charge, but also full effective action of the Dp-brane exactly.
Our method works for general unstable D-brane systems and provides a simple
proof of D-brane descent/ascent relations under the tachyon condensation. In
the lowest dimensional unstable D-brane system, called K-matrix theory,
D-branes are described in terms of operator algebra. We show the equivalence of
the geometric and algebraic descriptions of a D-brane world-volume manifold
using the equivalence between path integral and operator formulation of the
boundary quantum mechanics. As a corollary, the Atiyah-Singer index theorem is
naturally obtained by looking at the coupling to RR-fields. We also generalize
the argument to type I string theory.Comment: 63 pages, LaTeX, no figures, v2: references adde
TGF-β-dependent reprogramming of amino acid metabolism induces epithelial–mesenchymal transition in non-small cell lung cancers
Epithelial–mesenchymal transition (EMT)—a fundamental process in embryogenesis and wound healing—promotes tumor metastasis and resistance to chemotherapy. While studies have identified signaling components and transcriptional factors responsible in the TGF-β-dependent EMT, whether and how intracellular metabolism is integrated with EMT remains to be fully elucidated. Here, we showed that TGF-β induces reprogramming of intracellular amino acid metabolism, which is necessary to promote EMT in non-small cell lung cancer cells. Combined metabolome and transcriptome analysis identified prolyl 4-hydroxylase α3 (P4HA3), an enzyme implicated in cancer metabolism, to be upregulated during TGF-β stimulation. Further, knockdown of P4HA3 diminished TGF-β-dependent changes in amino acids, EMT, and tumor metastasis. Conversely, manipulation of extracellular amino acids induced EMT-like responses without TGF-β stimulation. These results suggest a previously unappreciated requirement for the reprogramming of amino acid metabolism via P4HA3 for TGF-β-dependent EMT and implicate a P4HA3 inhibitor as a potential therapeutic agent for cancer
D-branes, Matrix Theory and K-homology
In this paper, we study a new matrix theory based on non-BPS D-instantons in
type IIA string theory and D-instanton - anti D-instanton system in type IIB
string theory, which we call K-matrix theory. The theory correctly incorporates
the creation and annihilation processes of D-branes. The configurations of the
theory are identified with spectral triples, which are the noncommutative
generalization of Riemannian geometry a la Connes, and they represent the
geometry on the world-volume of higher dimensional D-branes. Remarkably, the
configurations of D-branes in the K-matrix theory are naturally classified by a
K-theoretical version of homology group, called K-homology. Furthermore, we
argue that the K-homology correctly classifies the D-brane configurations from
a geometrical point of view. We also construct the boundary states
corresponding to the configurations of the K-matrix theory, and explicitly show
that they represent the higher dimensional D-branes.Comment: 53 pages, corrected a few typos, version published in JHE
Brane Decay and Death of Open Strings
We show how open strings cease to propagate when unstable D-branes decay. The
information on the propagation is encoded in BSFT two-point functions for
arbitrary profiles of open string excitations. We evaluate them in tachyon
condensation backgrounds corresponding to (i) static spatial tachyon kink (=
lower dimensional BPS D-brane) and (ii) homogeneous rolling tachyon. For (i)
the propagation is restricted to the directions along the tachyon kink, while
for (ii) all the open string excitations cease to propagate at late time and
are subject to a collapsed light cone characterized by Carrollian contraction
of Lorentz group.Comment: 19 pages, published version (typos corrected, a reference added
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