55 research outputs found
Theory of heterotic SIS Josephson junctions between single- and multi-gap superconductors
Using the functional integral method, we construct a theory of heterotic SIS
Josephson junctions between single- and two-gap superconductors. The theory
predicts the presence of in-phase and out-of-phase collective oscillation modes
of superconducting phases. The former corresponds to the Josephson plasma mode
whose frequency is drastically reduced for s-wave symmetry, and the
latter is a counterpart of Leggett's mode in Josephson junctions. We also
reveal that the critical current and the Fraunhofer pattern strongly depend on
the symmetry type of the two-gap superconductor
Ambegaokar-Baratoff relations of Josephson critical current in heterojunctions with multi-gap superconductors
An extension of the Ambegaokar-Baratoff relation to a
superconductor-insulator-superconductor (SIS) Josephson junction with multiple
tunneling channels is derived. Appling the resultant relation to a SIS
Josephson junction formed by an iron-based (five-band) and a single-band
Bardeen-Cooper-Schrieffer (BCS) type superconductors, a theoretical bound of
the Josephson critical current () multiplied by the resistance of
the junction () is given. We reveal that such a bound is useful for
identifying the pairing symmetry of iron-pnictide superconductors. One finds
that if a measured value of is smaller than the bound then
the symmetry is -wave, and otherwise -wave without any sign changes.
In addition, we stress that temperature dependence of is
sensitive to the difference of the gap functions from the BCS type gap formula
in the above heterojunction.Comment: 7 pages, 6 figure
In-phase electrodynamics and terahertz wave emission in extended intrinsic Josephson junctions
Relationship between the cAMP levels in leukocytes and the cytokine balance in patients surviving gram negative bacterial pneumonia
Lipopolysaccharide-stimulated leukocytes secrete proinflammatory cytokines including tumor necrosis factor-α and interleukin-12. Over-activation of host defense systems may result in severe tissue damage and requires regulation. Granulocyte colony-stimulating factor and interleukin-10 are candidate cytokines for inducing tolerance to lipopolysaccharide re-stimulation. We compared cytokines secreted by lipopolysaccharide-stimulated blood cells from patients who had survived gram negative bacterial pneumonia (Pseudomonas aeruginosa, Escherichia coli or Proteus mirabilis, n = 26) and age-matched healthy volunteers (n = 18). Interleukin-12p70 and tumor necrosis factor-α expression was significantly lower in patients (p = 0.0039 and p<0.001) compared to healthy controls, while granulocyte colony-stimulating factor production was markedly higher in patients (p<0.001). Levels of interleukin-10 were comparable. Granulocyte colony-stimulating factor expression was inversely correlated with interleukin-12p70 (R = −0.71, p<0.001) and tumor necrosis factor-α (R = −0.64, p<0.001) expression; interleukin-10 showed no significant correlation. In unstimulated leukocytes from patients, cAMP levels were significantly raised (p = 0.020) and were correlated inversely with interleukin-12p70 levels (R = −0.81, p<0.001) and directly with granulocyte colony-stimulating factor (R = 0.72, p = 0.0020), matrix metalloproteinase-9 (R = 0.67, p = 0.0067) and interleukin-10 (R = 0.54, p = 0.039) levels. Our results demonstrate that granulocyte colony-stimulating factor production by lipopolysaccharide-stimulated leukocytes is a useful indicator of tolerance induction in surviving pneumonia patients and that measuring cAMP in freshly isolated leukocytes may also be clinically significant
Simulation of I-V Hysteresis Branches in An Intrinsic Stack of Josephson Junctions in High Superconductors
I-V characteristics of the high T superconductor
BiSrCaCO shows a strong hysteresis, producing many
branches. The origin of hysteresis jumps is studied by use of the model of
multi-layered Josephson junctions proposed by one of the authors (T. K.). The
charging effect at superconducting layers produces a coupling between the next
nearest neighbor phase-differences, which determines the structure of
hysteresis branches. It will be shown that a solution of phase motions is
understood as a combination of rotating and oscillating phase-differences, and
that, at points of hysteresis jumps, there occurs a change in the number of
rotating phase-differences. Effects of dissipation are analyzed. The
dissipation in insulating layers works to damp the phase motion itself, while
the dissipation in superconducting layers works to damp relative motions of
phase-differences. Their effects to hysteresis jumps are discussed.Comment: 18 pages, Latex, 8 figures. To be appear in Phys.Rev.B Vol.60(1999
A case of fulminant amebic colitis that could be saved
An 80-year-old man was admitted to a neighboring hospital with severe diarrhea and bloody stools. He did not have a remarkable medical history, was not homosexual, and had not traveled outside the country for several years. Colonoscopy was performed on the day of admission and revealed multiple ulcerations with edematous mucosa throughout the colorectum. Histopathological findings of biopsy specimen could not identify the reason for the inflamed colon. On postadmission day 6, the patient developed severe abdominal pain and underwent an emergent surgery for pan-peritonitis due to bowel perforation. The laparotomy revealed glossy fecal pan-peritonitis with perforation of the sigmoid colon; necrosis was observed through the entire length of the colon. The colonic tissue was extremely fragile and exhibited a blotting paper-like appearance. Total colectomy, sigmoid mucous fistula, ileostomy, and intraperitoneal drainage were performed. On postadmission day 12, histopathological findings of resected specimen raised the suspicion of amebic dysentery, and we accordingly treated him with metronidazole (2,250 mg/day) administered orally. Abdominal CT images taken on days 12 and 20 postadmission showed multiple liver abscesses, which improved following metronidazole administration. Metronidazole was discontinued 14 days after initiation as the patient’s general condition improved. His condition remained stable thereafter, and he was transferred two months after admission
Antiferromagnetism and single-particle properties in the two-dimensional half-filled Hubbard model: a non-linear sigma model approach
We describe a low-temperature approach to the two-dimensional half-filled
Hubbard model which allows us to study both antiferromagnetism and
single-particle properties. This approach ignores amplitude fluctuations of the
antiferromagnetic (AF) order parameter and is valid below a crossover
temperature which marks the onset of AF short-range order. Directional
fluctuations (spin waves) are described by a non-linear sigma model
(NLM) that we derive from the Hubbard model. At zero temperature and
weak coupling, our results are typical of a Slater antiferromagnet. The AF gap
is exponentially small; there are well-defined Bogoliubov quasi-particles
(QP's) (carrying most of the spectral weight) coexisting with a high-energy
incoherent excitation background. As increases, the Slater antiferromagnet
progressively becomes a Mott-Heisenberg antiferromagnet. The Bogoliubov bands
evolve into Mott-Hubbard bands separated by a large AF gap. A significant
fraction of spectral weight is transferred from the Bogoliubov QP's to
incoherent excitations. At finite temperature, there is a metal-insulator
transition between a pseudogap phase at weak coupling and a Mott-Hubbard
insulator at strong coupling. Finally, we point out that our results
straightforwardly translate to the half-filled attractive Hubbard model, where
the charge and pairing fluctuations combine to
form an order parameter with SO(3) symmetry.Comment: Revtex4, 19 pages, 14 figures; (v2) final version as publishe
ドッキョウ イカ ダイガク コシガヤ ビョウイン ニオケル コウキンザイ ノ シヨウ ジッタイ チョウサ ト テキセイ シヨウ エノ トリクミ (<トクシュウ> カンセンショウ ノ サイキン ノ ドウコウ)
Related polymorphic F-box protein genes between haplotypes clustering in the BAC contig sequences around the S-RNase of Japanese pear
Most fruit trees in the Rosaceae exhibit self-incompatibility, which is controlled by the pistil S gene, encoding a ribonuclease (S-RNase), and the pollen S gene at the S-locus. The pollen S in Prunus is an F-box protein gene (SLF/SFB) located near the S-RNase, but it has not been identified in Pyrus and Malus. In the Japanese pear, various F-box protein genes (PpSFBB-α–γ) linked to the S-RNase are proposed as the pollen S candidate. Two bacterial artificial chromosome (BAC) contigs around the S-RNase genes of Japanese pear were constructed, and 649 kb around S4-RNase and 378 kb around S2-RNase were sequenced. Six and 10 pollen-specific F-box protein genes (designated as PpSFBB4-u1–u4, 4-d1–d2 and PpSFBB2-u1–u5, 2-d1–d5, respectively) were found, but PpSFBB4-α–γ and PpSFBB2-γ were absent. The PpSFBB4 genes showed 66.2–93.1% amino acid identity with the PpSFBB2 genes, which indicated clustering of related polymorphic F-box protein genes between haplotypes near the S-RNase of the Japanese pear. Phylogenetic analysis classified 36 F-box protein genes of Pyrus and Malus into two major groups (I and II), and also generated gene pairs of PpSFBB genes and PpSFBB/Malus F-box protein genes. Group I consisted of gene pairs with 76.3–94.9% identity, while group II consisted of gene pairs with higher identities (>92%) than group I. This grouping suggests that less polymorphic PpSFBB genes in group II are non-S pollen genes and that the pollen S candidates are included in the group I PpSFBB genes
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