Thermal Conductivity in the Bose-Einstein Condensed State of Triplons in the Bond-Alternating Spin-Chain System Pb2V3O9

In order to clarify the origin of the enhancement of the thermal conductivity in the Bose-Einstein Condensed (BEC) state of field-induced triplons, we have measured the thermal conductivity along the [101] direction parallel to spin-chains, $kappa_{\|[101]}$, and perpendicular to spin-chains, $kappa_{\perp[101]}$, of the S=1/2 bond-alternating spin-chain system Pb2V3O9 in magnetic fields up to 14 T. With increasing field at 3 K, it has been found that both $kappa_{\|[101]}$ and $kappa_{\perp[101]}$ are suppressed in the gapped normal state in low fields. In the BEC state of field-induced triplons in high fields, on the other hand, $kappa_{\|[101]}$ is enhanced with increasing field, while $kappa_{\perp[101]}$ is suppressed. That is, the thermal conductivity along the direction, where the magnetic interaction is strong, is markedly enhanced in the BEC state. Accordingly, our results suggest that the enhancement of $kappa_{\|[101]}$ in the BEC state is caused by the enhancement of the thermal conductivity due to triplons on the basis of the two-fluid model, as in the case of the superfluid state of liquid 4He.Comment: 5 pages, 3 figure

アヒル消化管における内分泌細胞の分布

食道から直腸末端までのアヒル消化管における内分泌細胞の存在と分布を,鉛ヘマトキシリン,塩酸トルイジンブルー,Sevier and Mungerの鍍銀法およびMassonの銀親和反応を用いて検索した。 鉛ヘマトキシリンと塩酸トルイジンブルーで染まる細胞は食道を除く消化管の全部位でみられ,好銀性細胞は腺胃粘膜,腺胃腺および腸管の全部位に,銀親和性細胞は腸管にのみみられた。 内分泌細胞の分布密度は,筋胃幽門部が最も多く,次が腺胃腺であり,腸は十二指腸,空腸,回腸,盲腸,結直腸の5部位とも同程度で幽門部の約1/2,腺胃粘膜および胃峡部は腺胃腺の1/10,筋胃中央部は前2部位よりも少なく最少であった。 筋胃幽門部は,筋胃と十二指腸を分けるわずかな粘膜ひだから筋胃側5㎜位の部分であり,この部に非銀親和性で非好銀性の内分泌細胞が高密度に存在することは興味ある所見である。 これら内分泌細胞の染色性および分布から,アヒル消化管における4種類以上の内分泌細胞の存在が推測された。The four histological methods, previously known to be useful in selective detection of endocrine cells, were applied to the duck digestive tracts, from oesophagus to colorectum. Cells stained with lead-hematoxylin and HC1-toluidine blue were observed in all regions of the duck digestive tracts with the exception of the oesophagus. Argyrophil cells were observed in proventricular mucosa and glands, and in the intestine. Argentaffin cells were observed only in the intestine. The frequency of endocrine cells in the duck digestive tracts was highest in the restricted region of gizzard mucosa where was called the pyloric region in this paper, next in the proventricular glands, equally about half of the frequency in the pyloric region in the five regions of the intestine, one tenth of that of the proventricular glands in the proventricular and isthmus mucosa, and the smallest frequency was noted in the central part of gizzard mucosa. The pyloric region was about 5mm anterior to the narrow mucosal fold separating the gizzard from the intestine. It was an interesting to find that the endocrine cells which were nonargentaffin and nonargyrophil were densely present in this region. From the staining properties and the distribution of the endocrine cells, the possibility of existence of four and more types of endocrine cells in the duck digestive tracts was discussed

Pseudogap Phase Boundary in Overdoped Bi_2Sr_2CaCu_2O_8 Studied by Measuring Out-of-plane Resistivity under the Magnetic Fields

The characteristic pseudogap temperature T* in Bi2Sr2CaCu2O8 system has been systematically evaluated as a function of doping, especially focusing on its overdoped region, by measuring the out-of-plane resistivity under the magnetic fields. Overdoped samples have been prepared by annealing TSFZ-grown Bi2Sr2CaCu2O8 single crystals under the high oxygen pressures (990 kgf/cm2). At a zero field, the out-of-plane resistivity showed a metallic behavior down to Tc (= 62 K), while under the magnetic fields of over 3 T,it showed typical upturn behavior from around 65 K upon decreasing temperature. This result suggests that the pseudogap and superconductivity are different phenomena.Comment: 2 pages, 2 figures. Final version accepted for the Proceedings of the M2S-IX Conference (Tokyo, September 2009

Magnetic field effect on Fe-induced short-range magnetic correlation and electrical conductivity in Bi1.75_{1.75}Pb0.35_{0.35}Sr1.90_{1.90}Cu0.91_{0.91}Fe0.09_{0.09}O6+y_{6+y}

We report electrical resistivity measurements and neutron diffraction studies under magnetic fields of Bi$_{1.75}$Pb$_{0.35}$Sr$_{1.90}$Cu$_{0.91}$Fe$_{0.09}$O$_{6+y}$, in which hole carriers are overdoped. This compound shows short-range incommensurate magnetic correlation with incommensurability $\delta=0.21$, whereas a Fe-free compound shows no magnetic correlation. Resistivity shows an up turn at low temperature in the form of $ln(1/T)$ and shows no superconductivity. We observe reduction of resistivity by applying magnetic fields (i.e., a negative magnetoresistive effect) at temperatures below the onset of short-range magnetic correlation. Application of magnetic fields also suppresses the Fe induced incommensurate magnetic correlation. We compare and contrast these observations with two different models: 1) stripe order, and 2) dilute magnetic moments in a metallic alloy, with associated Kondo behavior. The latter picture appears to be more relevant to the present results.Comment: 7 pages, 5 figure

Periostin is essential for cardiac healingafter acute myocardial infarction

Acute myocardial infarction (AMI) is a common and lethal heart disease, and the recruitment of fibroblastic cells to the infarct region is essential for the cardiac healing process. Although stiffness of the extracellular matrix in the infarct myocardium is associated with cardiac healing, the molecular mechanism of cardiac healing is not fully understood. We show that periostin, which is a matricellular protein, is important for the cardiac healing process after AMI. The expression of periostin protein was abundant in the infarct border of human and mouse hearts with AMI. We generated periostin−/− mice and found no morphologically abnormal cardiomyocyte phenotypes; however, after AMI, cardiac healing was impaired in these mice, resulting in cardiac rupture as a consequence of reduced myocardial stiffness caused by a reduced number of α smooth muscle actin–positive cells, impaired collagen fibril formation, and decreased phosphorylation of FAK. These phenotypes were rescued by gene transfer of a spliced form of periostin. Moreover, the inhibition of FAK or αv-integrin, which blocked the periostin-promoted cell migration, revealed that αv-integrin, FAK, and Akt are involved in periostin signaling. Our novel findings show the effects of periostin on recruitment of activated fibroblasts through FAK-integrin signaling and on their collagen fibril formation specific to healing after AMI

Characterization of the K2-19 Multiple-Transiting Planetary System via High-Dispersion Spectroscopy, AO Imaging, and Transit Timing Variations

K2-19 (EPIC201505350) is an interesting planetary system in which two transiting planets with radii ~ 7 $R_{Earth}$ (inner planet b) and ~ 4 $R_{Earth}$ (outer planet c) have orbits that are nearly in a 3:2 mean-motion resonance. Here, we present results of ground-based follow-up observations for the K2-19 planetary system. We have performed high-dispersion spectroscopy and high-contrast adaptive-optics imaging of the host star with the HDS and HiCIAO on the Subaru 8.2m telescope. We find that the host star is relatively old (>8 Gyr) late G-type star ($T_{eff}$ ~ 5350 K, $M_s$ ~ 0.9 $M_{Sun}$, and $R_{s}$ ~ 0.9 $R_{Sun}$). We do not find any contaminating faint objects near the host star which could be responsible for (or dilute) the transit signals. We have also conducted transit follow-up photometry for the inner planet with KeplerCam on the FLWO 1.2m telescope, TRAPPISTCAM on the TRAPPIST 0.6m telescope, and MuSCAT on the OAO 1.88m telescope. We confirm the presence of transit-timing variations, as previously reported by Armstrong and coworkers. We model the observed transit-timing variations of the inner planet using the synodic chopping formulae given by Deck & Agol (2015). We find two statistically indistinguishable solutions for which the period ratios ($P_{c}/P_{b}$) are located slightly above and below the exact 3:2 commensurability. Despite the degeneracy, we derive the orbital period of the inner planet $P_b$ ~ 7.921 days and the mass of the outer planet $M_c$ ~ 20 $M_{Earth}$. Additional transit photometry (especially for the outer planet) as well as precise radial-velocity measurements would be helpful to break the degeneracy and to determine the mass of the inner planet