Antiferromagnetic Zigzag Spin Chain in Magnetic Fields at Finite Temperatures

We study thermodynamic behaviors of the antiferromagnetic zigzag spin chain in magnetic fields, using the density-matrix renormalization group method for the quantum transfer matrix. We focus on the thermodynamics of the system near the critical fields in the ground-state magnetization process($M$-$H$ curve): the saturation field, the lower critical field associated with excitation gap, and the field at the middle-field cusp singularity. We calculate magnetization, susceptibility and specific heat of the zigzag chain in magnetic fields at finite temperatures, and then discuss how the calculated quantities reflect the low-lying excitations of the system related with the critical behaviors in the $M$-$H$ curve.Comment: accepted for publication in Physical Review

Human NK cell development in hIL-7 and hIL-15 knockin NOD/SCID/IL2rgKO mice.

The immune system encompasses acquired and innate immunity that matures through interaction with microenvironmental components. Cytokines serve as environmental factors that foster functional maturation of immune cells. Although NOD/SCID/IL2rgKO (NSG) humanized mice support investigation of human immunity in vivo, a species barrier between human immune cells and the mouse microenvironment limits human acquired as well as innate immune function. To study the roles of human cytokines in human acquired and innate immune cell development, we created NSG mice expressing hIL-7 and hIL-15. Although hIL-7 alone was not sufficient for supporting human NK cell development in vivo, increased frequencies of human NK cells were confirmed in multiple organs of hIL-7 and hIL-15 double knockin (hIL-7xhIL-15 KI) NSG mice engrafted with human hematopoietic stem cells. hIL-7xhIL-15 KI NSG humanized mice provide a valuable in vivo model to investigate development and function of human NK cells

Drift effects and the cosmic ray density gradient in a solar rotation period: First observation with the Global Muon Detector Network (GMDN)

We present for the first time hourly variations of the spatial density gradient of 50 GeV cosmic rays within a sample solar rotation period in 2006. By inversely solving the transport equation, including diffusion, we deduce the gradient from the anisotropy that is derived from the observation made by the Global Muon Detector Network (GMDN). The anisotropy obtained by applying a new analysis method to the GMDN data is precise and free from atmospheric temperature effects on the muon count rate recorded by ground based detectors. We find the derived north-south gradient perpendicular to the ecliptic plane is oriented toward the Helioshperic Current Sheet (HCS) (i.e. southward in the toward sector of the Interplanetary Magnetic Field (IMF) and northward in the away sector). The orientation of the gradient component parallel to the ecliptic plane remains similar in both sectors with an enhancement of its magnitude seen after the Earth crosses the HCS. These temporal features are interpreted in terms of a local maximum of the cosmic ray density at the HCS. This is consistent with the prediction of the drift model for the $A<0$ epoch. By comparing the observed gradient with the numerical prediction of a simple drift model, we conclude that particle drifts in the large-scale magnetic field play an important role in organizing the density gradient, at least in the present $A<0$ epoch. We also found that corotating interaction regions did not have such a notable effect. Observations with the GMDN provide us with a new tool for investigating cosmic ray transport in the IMF.Comment: 35 pages, 10 figures, submitted to the Astrophysical Journa

Integrated analysis of the oral and intestinal microbiome and metabolome of elderly people with more than 26 original teeth: a pilot study

Elderly subjects with more than 20 natural teeth have a higher healthy life expectancy than those with few or no teeth. The oral microbiome and its metabolome are associated with oral health, and they are also associated with systemic health via the oral-gut axis. Here, we analyzed the oral and gut microbiome and metabolome profiles of elderly subjects with more than 26 natural teeth. Salivary samples collected as mouth-rinsed water and fecal samples were obtained from 22 healthy individuals, 10 elderly individuals with more than 26 natural teeth and 24 subjects with periodontal disease. The oral microbiome and metabolome profiles of elderly individuals resembled those of subjects with periodontal disease, with the metabolome showing a more substantial differential abundance of components. Despite the distinct oral metabolome profiles, there was no differential abundance of components in the gut microbiome and metabolomes, except for enrichment of short-chain fatty acids in elderly subjects. Finally, to investigate the relationship between the oral and gut microbiome and metabolome, we analyzed bacterial coexistence in the oral cavity and gut and analyzed the correlation of metabolite levels between the oral cavity and gut. However, there were few associations between oral and gut for bacteria and metabolites in either elderly or healthy subjects. Overall, these results indicate distinct oral microbiome and metabolome profiles, as well as the lack of an oral-gut axis in elderly subjects with a high number of natural teeth

<症例>石灰化胃癌の1例

By upper gastrointestinal series, a 57 years-old woman was pointed out to have scattered calcifications along the greater curvature of the stomach. On computerized tomography, the calcifications distributed in the irregularly thickened gastric wall. With a diagnosis of calcified mucinous adenocarcinoma showing Borrmann type III, total gastrectomy with splenectomy was carried out. The characteristics of this lesion were briefly presented with a review of the literature.57歳女性の上部消化管透視において, 胃の大弯側に散在性の小斑点状の石灰化が指摘された. この石灰化は, 腹部コンビューター断層撮影では不規則に肥厚した胃壁内に存在した. ボールマン III 型の石灰化胃粘液腺癌の診断で胃全摘・脾摘を行った. 画像診断と肉眼標本によって石灰化を証明できた胃癌はまれであり, 本邦報告例では女性に多く, すべて進行癌であった. 腫瘍の粘液産生がこの石灰化に関与すると考えられている. また, 切除率や生存率がかなり低い疾患でもあり, 自験例も術後2年半で癌再発により死亡した. 文献的考察を加えて報告した

Sputtering of SiN films by 540 keV C^[2+]_[60] ions observed using high-resolution Rutherford backscattering spectroscopy

Amorphous silicon nitride films deposited on Si(0 0 1) were irradiated with 540 keV C[60] ions to fluences ranging from 2.5 × 10[11] to 1 × 10[14] ions/cm2. The composition depth profiles of the irradiated samples were measured using high-resolution Rutherford backscattering spectroscopy. Both silicon and nitrogen in the film decrease rapidly with fluence. From the observed result the sputtering yields are obtained as 3900 ± 500 N atoms/ion and 1500 ± 1000 Si atoms/ion. Such large sputtering yield cannot be explained by either the elastic sputtering or the electronic sputtering, indicating that the synergy effect between the elastic sputtering and the electronic sputtering plays an important role

Optimization of Soft Carbon Negative Electrode in Sodium-Ion Batteries Using Surface-Modified Mesophase-Pitch Carbon Fibers

Current efforts to improve sodium-ion batteries are heavily focused on developing high performance carbon materials for the negative electrode. With significant research, hard carbons have come to show massive storage capacities and fast discharge rates. On the other hand, soft carbons have received very little attention, though they likewise encompass a wide variety of materials with structures highly dependent on the starting material and preparation temperature. In our contribution, we systematically evaluate the electrochemical performance of soft carbon electrodes made from mesophase-pitch carbon fibers (MCF). By using felt electrodes, we evaluate the cyclic voltammetry of MCFs prepared at 600–1300 °C and show the best performance with MCF prepared between 700–950 °C. In addition, using a surface modification step with silver showed significantly improved voltammetry for all the materials. Electrochemical impedance measurements further indicated that the surface modification step could decrease both of charge transfer resistances and film resistances attributed to the solid electrolyte interphase. Upon comparing lithium- and sodium-cell, it was revealed that sodium-cell demonstrated more significant increase in current density and decrease in resistance through surface treatment. We further verified our results with measurements on single-fiber electrodes; an increase in currents and a decrease in impedance were also observed by the surface modification, as with the felt electrodes. Overall, we speculate our surface modification removes inhibitors, such as functional groups or impurities, on the MCF surface to prevent sluggish ion transfer or trapping during sodium insertion/extraction