180 research outputs found

    Time-Resolved Observation of Deposition Process of Ultrananocrystalline Diamond/Hydrogenated Amorphous Carbon Composite Films in Pulsed Laser Deposition

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    Optical emission spectroscopy was used to study pulsed laser ablation of graphite in a hydrogen atmosphere wherein ultrananocrystalline diamond (UNCD)/hydrogenated amorphous carbon (a-C:H) composite films were grown on heated substrates. Time-resolved photographs of a plume that expanded from a laser-irradiation spot toward a substrate were taken using a high-speed ICCD camera equipped with narrow-bandpass filters. While the emissions from C atoms and C2 dimers lasted above the laser-irradiation spot on the target, the emission from C+ ions lasted above the substrate surface for approximately 7 microseconds, although the emission lifetime of species is generally approximately 10 nanoseconds. This implies that C+ ions actively collided with each other above the substrate surface for such a long time. We believe that the keys to UNCD growth in PLD are the supply of highly energetic carbon species at a high density to the substrate and existence of atomic hydrogen during the growth

    Faint warm debris disks around nearby bright stars explored by AKARI and IRSF

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    Context: Debris disks are important observational clues for understanding planetary-system formation process. In particular, faint warm debris disks may be related to late planet formation near 1 AU. A systematic search of faint warm debris disks is necessary to reveal terrestrial planet formation. Aims: Faint warm debris disks show excess emission that peaks at mid-IR wavelengths. Thus we explore debris disks using the AKARI mid-IR all-sky point source catalog (PSC), a product of the second generation unbiased IR all-sky survey. Methods : We investigate IR excess emission for 678 isolated main-sequence stars for which there are 18 micron detections in the AKARI mid-IR all-sky catalog by comparing their fluxes with the predicted fluxes of the photospheres based on optical to near-IR fluxes and model spectra. The near-IR fluxes are first taken from the 2MASS PSC. However, 286 stars with Ks<4.5 in our sample have large flux errors in the 2MASS photometry due to saturation. Thus we have measured accurate J, H, and Ks band fluxes, applying neutral density (ND) filters for Simultaneous InfraRed Imager for Unbiased Survey (SIRIUS) on IRSF, the \phi 1.4 m near-IR telescope in South Africa, and improved the flux accuracy from 14% to 1.8% on average. Results: We identified 53 debris-disk candidates including eight new detections from our sample of 678 main-sequence stars. The detection rate of debris disks for this work is ~8%, which is comparable with those in previous works by Spitzer and Herschel. Conclusion: The importance of this study is the detection of faint warm debris disks around nearby field stars. At least nine objects have a large amount of dust for their ages, which cannot be explained by the conventional steady-state collisional cascade model.Comment: 17 pages, 21 figures, accepted for publication in Astronomy and Astrophysic

    Baseline serum PINP level is associated with the increase in hip bone mineral density seen with Romosozumab treatment in previously untreated women with osteoporosis

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    Summary: Baseline serum PINP value was significantly and independently associated with the increased bone mineral density (≥ 3%) in both total hip and femoral necks by 12 months of romosozumab treatment in patients with treatment-naive postmenopausal osteoporosis. Purpose: Some patients fail to obtain a sufficiently increased hip bone mineral density (BMD) by romosozumab (ROMO) treatment. This study aimed to investigate the prognostic factor for increased hip BMD with ROMO in patients with treatment-naive postmenopausal osteoporosis. Methods: This prospective, observational, and multicenter study included patients (n = 63: mean age, 72.6 years; T-scores of the lumbar spine [LS], − 3.3; total hip [TH], − 2.6; femoral neck [FN], − 3.3; serum type I procollagen N-terminal propeptide [PINP], 68.5 µg/L) treated by ROMO for 12 months. BMD and serum bone turnover markers were evaluated at each time point. A responder analysis was performed to assess the patient percentage, and both univariate and multivariate analyses were performed to investigate the factors associated with clinically significant increased BMD (≥ 3%) in both TH and FN. Results: Percentage changes of BMD from baseline in the LS, TH, and FN areas were 17.5%, 4.9%, and 4.3%, respectively. In LS, 96.8% of patients achieved ≥ 6% increased LS-BMD, although 57.1% could not achieve ≥ 3% increased BMD in either TH or FN. Multiple regression analysis revealed that only the baseline PINP value was significantly and independently associated with ≥ 3% increased BMD in both TH and FN (p = 0.019, 95% confidence interval = 1.006–1.054). The optimal cut-off PINP value was 53.7 µg/L with 54.3% sensitivity and 92.3% specificity (area under the curve = 0.752). Conclusions: In a real-world setting, baseline PINP value was associated with the increased BMD of TH and FN by ROMO treatment in treatment-naive patients.This version of the article has been accepted for publication, after peer review (when applicable) and is subject to Springer Nature’s AM terms of use, but is not the Version of Record and does not reflect post-acceptance improvements, or any corrections. The Version of Record is available online at: https://doi.org/10.1007/s00198-022-06642-1Kashii M., Kamatani T., Nagayama Y., et al. Baseline serum PINP level is associated with the increase in hip bone mineral density seen with Romosozumab treatment in previously untreated women with osteoporosis. Osteoporosis International 34, 563 (2023

    Computer simulation analysis of fracture dislocation of the proximal interphalangeal joint using the finite element method.

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    Stress is a proximal interphalangeal (PIP) joint model was analyzed by the two-dimensional and three-dimensional finite element methods (FEM) to study the onset mechanisms of the middle phalangeal base fracture. The structural shapes were obtained from sagittally sectioned specimens of the PIP joint for making FEM models. In those models, four different material properties were given corresponding to cortical bone, subchondral bone, cancellous bone and cartilage. Loading conditions were determined by estimating the amount and position of axial pressure added to the middle phalanx. A general finite element program (MARC) was used for computer simulation analysis. The results of the fracture experiments compared with the clinical manifestation of the fractures justify the applicability of the computer simulation models using FEM analysis. The stress distribution changed as the angle of the PIP joint changed. Concentrated stress was found on the volar side of the middle phalangeal base in the hyperextension position, and was found on the dorsal side in the flexion position. In the neutral position, the stress was found on both sides. Axial stress on the middle phalanx causes three different types of fractures (volar, dorsal and both) depending upon the angle of the PIP joint. These results demonstrate that the type of PIP joint fracture dislocation depends on the angle of the joint at the time of injury. The finite element method is one of the most useful methods for analyzing the onset mechanism of fractures.</p

    The significance of extended lymphadenectomy for colorectal cancer with isolated synchronous extraregional lymph node metastasis

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    SummaryBackground/ObjectiveThe significance of extended lymphadenectomy for colorectal cancer with extraregional lymph node metastasis, such as para-aortic lymph node metastasis, has not been established. The purpose of this study was to evaluate the significance of extended lymphadenectomy for colorectal cancer with synchronous isolated extraregional lymph node metastasis.MethodsBetween July 2004 and December 2013, 16 patients with synchronous extraregional lymph node metastasis without other organ metastases underwent curative resection and extended lymphadenectomy (R0 group). The clinical characteristics and survival outcomes of the R0 group were compared with those of 12 patients with extraregional lymph node metastasis who underwent palliative surgery (control group).ResultsIn the R0 group, the 5-year cancer-specific survival (CSS) rate was 70.3% and the 5-year relapse-free survival (RFS) rate was 60.5%. The 5-year CSS differed significantly between the R0 and control groups (70.3% vs. 12.5%; p = 0.0003). Univariate analyses revealed that the total numbers of metastatic lymph nodes and metastatic regional lymph nodes present were significantly associated with RFS (p = 0.019 for both).ConclusionFindings from our study suggest that extended lymphadenectomy for colorectal cancer with synchronous isolated extraregional lymph node metastasis might be effective in carefully selected patients
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