1,200 research outputs found

    ^{31}P and ^{75}As NMR evidence for a residual density of states at zero energy in superconducting BaFe_2(As_{0.67}P_{0.33})_2

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    ^{31}P and ^{75}As NMR measurements were performed in superconducting BaFe_2(As_{0.67}P_{0.33})_2 with T_c = 30 K. The nuclear-spin-lattice relaxation rate T_1^{-1} and the Knight shift in the normal state indicate the development of antiferromagnetic fluctuations, and T_1^{-1} in the superconducting (SC) state decreases without a coherence peak just below T_c, as observed in (Ba_{1-x}K_{x})Fe_2As_2. In contrast to other iron arsenide superconductors, the T_1^{-1} \propto T behavior is observed below 4K, indicating the presence of a residual density of states at zero energy. Our results suggest that strikingly different SC gaps appear in BaFe_2(As_{1-x}P_{x})_2 despite a comparable T_c value, an analogous phase diagram, and similar Fermi surfaces to (Ba_{1-x}K_{x})Fe_2As_2.Comment: 4 pages, 5 figure

    Magnetic and superconducting properties of the heavy-fermion CeCoIn5 epitaxial film probed by nuclear quadrupole resonance

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    Since the progress in the fabrication techniques of thin-films of exotic materials such as strongly correlated heavy-fermion compounds, microscopic studies of the magnetic and electronic properties inside the films have been needed. Herein, we report the first observation of 115In nuclear quadrupole resonance (NQR) in an epitaxial film of the heavy-fermion superconductor CeCoIn5, for which the microscopic field gradient within the unit cell as well as magnetic and superconducting properties at zero field are evaluated. We find that the nuclear spin-lattice relaxation rate in the film is in excellent agreement with that of bulk crystals, whereas the NQR spectra show noticeable shifts and significant broadening indicating a change in the electric-field distribution inside the film. The analysis implies a displacement of In layers in the film, which however does not affect the magnetic fluctuations and superconducting pairing. This implies that inhomogeneity of the electronic field gradient in the film sample causes no pair breaking effect.Comment: 12 pages, 6 figure

    The distribution and number of Leu-7 (CD57) positive cells in lung tissue from patients with pulmonary fibrosis.

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    Leu-7 positive lymphocytes, including natural killer cells, play an important role in the immune system's surveillance function to prevent the development of cancer. The incidence of lung cancer is significantly high in patients with end-stage pulmonary fibrosis. We hypothesized that the number of Leu-7 positive cells may be decreased in areas of severe pulmonary fibrosis. To demonstrate this, Leu-7 positive cells were immunohistochemically stained in 41 lung specimens obtained from patients with idiopathic pulmonary fibrosis and pulmonary fibrosis associated with collagen vascular disorders. The number of Leu-7 positive cells was evaluated according to the pathological findings. In pathologically normal lung, Leu-7 positive cells were mostly found within the capillaries of the septa and rarely in the alveolar space or the stroma. The number of Leu-7 positive cells was 0.69 +/- 0.15 in areas of advanced fibrosis (n = 41), 2.39 +/- 0.60 in areas that had newly developeing fibrosis (n = 41), 1.14 +/- 0.57 in bronchiolitis obliterans organizing pneumonia (n = 9), and 1.35 +/- 0.87 in diffuse alveolar damage (DAD) (n = 11). The number of Leu-7 positive cells in areas of newly developing fibrosis (2.39 +/- 0.60) was significantly higher than that in areas of established fibrosis (0.69 +/- 0.15, P &#60; 0.05). Our present study demonstrates a significant decrease in the number of Leu-7 positive cells in areas of advanced fibrosis. This evidence may partly explain the high incidence of lung cancer associated with pulmonary fibrosis.</p

    Term delivery choriocarcinoma patient with brain and lung metastases successfully treated by etoposide, methotrexate, actomycin D, cyclophosphamide and vincristine (EMA-CO) chemotherapy.

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    It is well known that antecedent term delivery and metastasis to sites other than the lungs and vagina are high risk factors for patients with gestational trophoblastic neoplasia. Here we report on a patient with choriocarcinoma who presented with brain and lung metastases after term delivery and was treated by EMA-CO chemotherapy. A 31-year-old woman delivered a healthy infant at term. Frequent episodes of hemoptysis occurred beginning 3 weeks after the delivery. On admission to our hospital, she had lesions in the uterus, lungs and brain as well as motor aphasia and hemiplagia. The pretreatment beta-hCG level was 21,000 ng/ml and the WHO score was 16 (high-risk group). The EMA-CO regimen was administrated as first-line chemotherapy and the patient achieved complete remission after 7 courses. Treatment was terminated after 11 courses and maintained with etoposide (25 mg/day) for 6 months. The patient has remained in complete remission for more than 16 years without other adjuvant therapies. We believe that EMA-CO can currently be considered the regimen of first choice for most high-risk patients with gestational trophoblastic neoplasia in view of its effectiveness and excellent tolerability.</p

    Emergence of Orbital Nematicity in the Tetragonal Phase of BaFe2_2(As1x_{1-x}Px_x)2_2

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    We report on 75^{75}As-NMR measurements in single crystalline BaFe2_{2}(As0.96_{0.96}P0.04_{0.04})2_{2} for magnetic fields parallel to the orthorhombic [110]o[110]_{\rm o} and [100]o[100]_{\rm o} directions above the structural transition temperature TS121T_{\rm S}\simeq121 K. A large difference in the linewidth between the two field directions reveals in-plane anisotropy of the electric field gradient, even in the tetragonal phase. This provides microscopic evidence of population imbalance between As-4px4p_{x} and 4py4p_{y} orbitals, which reaches nxny/nx+ny15|n_x-n_y|/|n_x+n_y| \sim 15\% at TTST\rightarrow T_{\rm S} and is a natural consequence of the orbital ordering of Fe-3dxzd_{xz} and dyzd_{yz} electrons. Surprisingly, this orbital polarization is found to be already static near room temperature, suggesting that it arises from the pinning of anisotropic orbital fluctuations by disorder. The effect is found to be stronger below 160\sim 160 K, which coincides with the appearance of nematicity in previous torque and photoemission measurements. These results impose strong constraints on microscopic models of the nematic state.Comment: 6 pages, 6 figures. Supplemental Materials are included. To appear in J. Phys. Soc. Jpn. (Vol.84 No. 4

    Pathways and variability of the Antarctic Intermediate Water in the western equatorial Pacific Ocean.

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    In the western equatorial Pacific the low-salinity core of Antarctic Intermediate Water (AAIW) is found at about 800 m depth between potential density levels σθ = 27.2 and 27.3. The pathways of AAIW and the degradation of its core are studied, from the Bismarck Sea to the Caroline Basins and into the zonal equatorial current system. Both historical and new observational data, and results from numerical circulation model runs are used. The observations include hydrographic stations from German and Japanese research vessels, and Eulerian and Lagrangian current measurements. The model is the JAMSTEC high-resolution numerical model based on the Modular Ocean Model (MOM 2). The general agreement between results from the observations and from the model enables us to diagnose properties and to provide new information on the AAIW. The analysis confirms the paramount influence of topography on the spreading of the AAIW tongue north of New Guinea. Two cores of AAIW are found in the eastern Bismarck Sea. One core originates from Vitiaz Strait and one from St. George’s Channel, probably arriving on a cyclonic pathway. They merge in the western Bismarck Sea without much change in their total salt content, and the uniform core then increases considerably in salt content when subjected to mixing in the Caroline Basins. Hydrographic and moored current observations as well as model results show a distinct annual signal in salinity and velocity in the AAIW core off New Guinea. It appears to be related to the monsoonal change that is typically found in the near-surface waters in the region. Lagrangian data are used to investigate the structure of the deep New Guinea Coastal Undercurrent, the related cross-equatorial flow and eddy-structure, and the embedment in the zonal equatorial current system. Results from 17 neutrally buoyant RAFOS floats, ballasted to drift in the AAIW core layer, are compared with a numerical tracking experiment. In the model 73 particles are released at five-day intervals from Station J (2.5°N, 142°E), simulating currents at a moored time series station north of New Guinea. Observed and model track patterns are fairly consistent in space and season. Floats cross the equator preferably north of Cenderawasih Bay, with a maximum range in eddy-motion in this region north of New Guinea. The northward route at 135°E is also reflected in a low-salinity tongue reaching up to 3°N. At that longitude the floats seem to ignore the zonally aligned equatorial undercurrents. Farther to the east (139 145°E), however, the float observations are consistent with low-latitude bands of intermediate currents

    X-ray magnetic circular dichroism and photoemission study of the diluted ferromagnetic semiconductor Zn1x_{1-x}Crx_xTe

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    We have performed x-ray magnetic circular dichroism (XMCD) and valence-band photoemission studies of the diluted ferromagnetic semiconductor Zn1x_{1-x}Crx_xTe. XMCD signals due to ferromagnetism were observed at the Cr 2p absorption edge. Comparison with atomic multiplet calculations suggests that the magnetically active component of the Cr ion was divalent under the tetrahedral crystal field with tetragonal distortion along the crystalline a-, b-, and c-axes. In the valence-band spectra, spectral weight near the Fermi level was strongly suppressed, suggesting the importance of Jahn-Teller effect and the strong Coulomb interaction between the Cr 3d electrons

    Characterization of spliced leader trans-splicing in a photosynthetic rhizarian amoeba, Paulinella micropora, and its possible role in functional gene transfer

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    Paulinella micropora is a rhizarian thecate amoeba, belonging to a photosynthetic Paulinella species group that has a unique organelle termed chromatophore, whose cyanobacterial origin is distinct from that of plant and algal chloroplasts. Because acquisition of the chromatophore was quite a recent event compared with that of the chloroplast ancestor, the Paulinella species are thought to be model organisms for studying the early process of primary endosymbiosis. To obtain insight into how endosymbiotically transferred genes acquire expression competence in the host nucleus, here we analyzed the 5′ end sequences of the mRNAs of P. micropora MYN1 strain with the aid of a cap-trapper cDNA library. As a result, we found that mRNAs of 27 genes, including endosymbiotically transferred genes, possessed the common 5′ end sequence of 28–33 bases that were posttranscriptionally added by spliced leader (SL) trans-splicing. We also found two subtypes of SL RNA genes encoded by the P. micropora MYN1 genome. Differing from the other SL trans-splicing organisms that usually possess poly(A)-less SL RNAs, this amoeba has polyadenylated SL RNAs. In this study, we characterize the SL trans-splicing of this unique organism and discuss the putative merits of SL trans-splicing in functional gene transfer and genome evolution
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