Sintering behavior of ultrafine silicon carbide powders obtained by vapor phase reaction

The sintering behavior of ultrafine SiC powder with average particle size of about 0.01-0.06 microns produced by a vapor phase reaction of the Me4Si-H2 system was studied at the temperature range of 1400-2050 deg. It was found that the homogeneous dispersion of C on SiC particles is important to remove the surface oxide layer effectively. B and C and inhibitive effect on SiC grain growth

Regulatory T cells in melanoma revisited by a computational clustering of FOXP3+ T cell subpopulations

CD4+ T cells that express the transcription factor FOXP3 (FOXP3+ T cells) are commonly regarded as immunosuppressive regulatory T cells (Treg). FOXP3+ T cells are reported to be increased in tumour-bearing patients or animals, and considered to suppress anti-tumour immunity, but the evidence is often contradictory. In addition, accumulating evidence indicates that FOXP3 is induced by antigenic stimulation, and that some non-Treg FOXP3+ T cells, especially memory-phenotype FOXP3low cells, produce proinflammatory cytokines. Accordingly, the subclassification of FOXP3+ T cells is fundamental for revealing the significance of FOXP3+ T cells in tumour immunity, but the arbitrariness and complexity of manual gating have complicated the issue. Here we report a computational method to automatically identify and classify FOXP3+ T cells into subsets using clustering algorithms. By analysing flow cytometric data of melanoma patients, the proposed method showed that the FOXP3+ subpopulation that had relatively high FOXP3, CD45RO, and CD25 expressions was increased in melanoma patients, whereas manual gating did not produce significant results on the FOXP3+ subpopulations. Interestingly, the computationally-identified FOXP3+ subpopulation included not only classical FOXP3high Treg but also memory-phenotype FOXP3low cells by manual gating. Furthermore, the proposed method successfully analysed an independent dataset, showing that the same FOXP3+ subpopulation was increased in melanoma patients, validating the method. Collectively, the proposed method successfully captured an important feature of melanoma without relying on the existing criteria of FOXP3+ T cells, revealing a hidden association between the T cell profile and melanoma, and providing new insights into FOXP3+ T cells and Treg

Prognostic Factors in Cutaneous Squamous Cell Carcinoma: Is Patient Delay in Hospital Visit a Predictor of Survival?

The patient's delay in the visit to a hospital seems to play an important role in prognosis in invasive cutaneous squamous cell carcinoma (SCC). This report explored prognostic factors of cutaneous SCC focusing on patient delay in hospital visit. Data of 117 Japanese patients who were treated for invasive cutaneous SCC in our facility between 2000 and 2010 were used for analysis. A multivariate Cox proportional-hazard modelling revealed that a pair of TNM stage (hazard ratio, 5.0; 95% CI, 1.8 to 13.9) and poorer histological differentiation (hazard ratio, 3.2; 95% CI, 0.93 to 10.3), and a pair of tumour size (hazard ratio, 1.02; 95% CI, 1.004 to 1.04) and rapid growth (hazard ratio, 8.25; 95% CI, 1.29 to 52.7) were a prognostic factor whereas patient delay in hospital visit was not. However, patient delay in hospital visit was correlated with larger tumour size

Stellar Overdensity in the Local Arm in Gaia DR2

Using the cross-matched data of Gaia DR2 and the 2MASS Point Source Catalog, we investigated the surface density distribution of stars aged ~1 Gyr in the thin disk in the range of 90° ≤ l ≤ 270°. We selected 4654 stars above the turnoff corresponding to the age ~1 Gyr, that fall within a small box region in the color–magnitude diagram, (J − K s )0 versus M(K s ), for which the distance and reddening are corrected. The selected sample shows an arm-like overdensity at 90° ≤ l ≤ 190°. This overdensity is located close to the Local Arm traced by high-mass star-forming regions (HMSFRs), but its pitch angle is slightly larger than that of the HMSFR-defined arm. Although the significance of the overdensity we report is marginal, its structure poses questions concerning both of the competing scenarios of spiral arms, the density-wave theory, and the dynamic spiral arm model. The offset between the arms traced by stars and HMSFRs, i.e., gas, is difficult to explain using the dynamic arm scenario. On the other hand, the pitch angle of the stellar Local Arm, if confirmed, is larger than that of the Perseus arm, and is difficult to explain using the classical density-wave scenario. The dynamic arm scenario can explain the pitch angle of the stellar Local Arm, if the Local Arm is in a growing up phase, while the Perseus arm is in a disrupting phase. Our result provide a new and complex picture of the Galactic spiral arms, and encourages further studies

Polarised target for Drell-Yan experiment in COMPASS at CERN, part I

In the polarised Drell-Yan experiment at the COMPASS facility in CERN pion beam with momentum of 190 GeV/c and intensity about $10^8$ pions/s interacted with transversely polarised NH$_3$ target. Muon pairs produced in Drel-Yan process were detected. The measurement was done in 2015 as the 1st ever polarised Drell-Yan fixed target experiment. The hydrogen nuclei in the solid-state NH$_3$ were polarised by dynamic nuclear polarisation in 2.5 T field of large-acceptance superconducting magnet. Large helium dilution cryostat was used to cool the target down below 100 mK. Polarisation of hydrogen nuclei reached during the data taking was about 80 %. Two oppositely polarised target cells, each 55 cm long and 4 cm in diameter were used. Overview of COMPASS facility and the polarised target with emphasis on the dilution cryostat and magnet is given. Results of the polarisation measurement in the Drell-Yan run and overviews of the target material, cell and dynamic nuclear polarisation system are given in the part II.Comment: 4 pages, 2 figures, Proceedings of the 22nd International Spin Symposium, Urbana-Champaign, Illinois, USA, 25-30 September 201

Near-threshold Lambda(1520) production by the gamma p -> K+Lambda(1520) reaction at forward K+ angles

Differential cross sections and photon-beam asymmetries for the gamma p -> K+ Lambda(1520) reaction have been measured with linearly polarized photon beams at energies from the threshold to 2.4 GeV at 0.6<cos(theta)<1. A new bump structure was found at W=2.11 GeV in the cross sections. The bump is not well reproduced by theoretical calculations introducing a nucleon resonance with J<=3/2. This result suggests that the bump might be produced by a nucleon resonance possibly with J>=5/2 or by a new reaction process, for example an interference effect with the phi photoproduction having a similar bump structure in the cross sections.Comment: 5 pages, 4 figures, published in Phys. Rev. Let