158 research outputs found

    Stability of vacancies in β-type Ti-15Mo-5Zr-3Al alloy fabricated via laser powder bed fusion

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    The structural instability in the β-type titanium alloys could affect the stability of vacancies. The stability of vacancies in a β-type Ti-15Mo-5Zr-3Al alloy, fabricated via laser powder bed fusion (LPBF), was investigated using positron annihilation spectroscopy and first-principles calculations. The observed positron lifetimes were close to the experimental and calculated bulk lifetime of Ti-15Mo-5Zr-3Al, which indicates that vacancies were not detected in Ti-15Mo-5Zr-3Al by positron lifetime measurements. Therefore, for the first time, it has been confirmed that quenched-in vacancies are not introduced in the LPBF-manufactured β-type Ti-15Mo-5Zr-3Al despite the fast cooling rate in LPBF process. This feature is preferable for the structural stability in biomedical and industrial applications. The calculated atomic displacement from the ideal bcc lattice positions decreased in β-type Ti-Mo alloys with increasing Mo concentration, indicating that the bcc structure was stabilized by the added Mo. The calculated vacancy formation energies of Ti atoms in β-type Ti-14.5Mo and Ti-27.0Mo alloys exhibited an increasing trend with an increasing number of neighboring Mo atoms. Mo atoms also increased the migration energies of the neighboring paths of vacancies. The calculated results for Ti-15Mo-5Zr-3Al suggest that, while the bcc structure was stabilized by the Mo atoms in Ti-15Mo-5Zr-3Al, the migration and formation energies were still low enough for the diffusion of vacancies.Mizuno M., Sugita K., Do K., et al. Stability of vacancies in β-type Ti-15Mo-5Zr-3Al alloy fabricated via laser powder bed fusion. Additive Manufacturing Letters 7, 100162 (2023); https://doi.org/10.1016/j.addlet.2023.100162

    A usage-centered approach to the promotion of Institutional Repository

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    This presentation explains the four projects of Digital Repository Federation in Japan from the view points of a usage-centered approach to institutional repositories.This is a presentation for SPARC Digital Repository Meeting 2008 held by SPARC, SPARC Europe, SPARC Japan on the 17th and 18the of Novemver 2008 at Baltimore in the United States

    Disappearance of lung adenocarcinoma after total en bloc spondylectomy using frozen tumor-bearing vertebra for reconstruction

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    Purpose: Total en bloc spondylectomy (TES) is a surgical procedure performed to achieve complete resection of an aggressive benign spinal tumor or a malignant spinal tumor. When reconstructing the spine after resection, we have been using liquid nitrogen-frozen resected spine bearing tumor as a bone graft, expecting an immunological response to tumor-specific antigen(s). The purpose of this article is to report a successful treatment case of lung adenocarcinoma metastasis with TES and this cryotherapy. Methods: A 59-year-old male presented with rapid progression of neurological deterioration of the lower limbs due to a spinal metastasis from T8 to T10. The primary lung adenocarcinoma had already been excised under thoracoscopy. The patient underwent TES with reconstruction using frozen tumor-bearing vertebra for the bone graft. Results: One month after surgery, a new nodule appeared at the right middle lobe of the lung. However, we carried out no biopsy of the newly emerged nodule and the patient received no adjuvant chemotherapy or radiotherapy. Six months after surgery, the tumor vanished. No local recurrence or metastasis of the tumor has been observed until now. Conclusions: TES with a liquid nitrogen-frozen tumor specimen could be a promising therapeutic option for cancer patients with spine metastasis. © 2015 Springer-Verlag Berlin HeidelbergEmbargo Period 12 month

    Repeated total en bloc spondylectomy for spinal metastases at different sites in one patient

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    Purpose: Total en bloc spondylectomy (TES) is accompanied by preoperative embolization of segmental arteries, which is limited to three consecutive levels to avoid the risk of spinal cord ischemia. We retrospectively examined the efficacy and safety of repeated TES with embolization of more than three levels of segmental arteries. Methods: Seven patients underwent TES twice for spinal metastases at different levels. Every patient underwent embolization of the bilateral segmental arteries before each surgery. We assessed the total number of segmental arteries embolized, the existence of Adamkiewicz arteries during the embolization procedure, intraoperative blood loss, and the motor function of the lower limbs, using the American Spinal Injury Association (ASIA) motor score. Results: No patient experienced any motor deficit after embolization. During the embolization procedure, an Adamkiewicz artery was depicted in five patients, which precluded embolization at that level. The median number of segmental arteries embolized in total was 9 (9–11). Intraoperative blood loss (median, IQR) was 480 (420–630) ml during the first surgery and 520 (280–600) ml during the second surgery. The ASIA motor scores (median, IQR) were as follows; 100 (98–100) (first admission), 100 (100–100) (first discharge), 100 (98–100) (second admission), and 97 (94–100) (second discharge). No patients had developed statistically significant neurological deterioration, and there had been no local recurrence after a median follow-up of 17.8 months (range 1–51 months). Conclusion: Repeated TES procedures can be performed safely even if more than three levels of segmental arteries are embolized. © 2015, Springer-Verlag Berlin Heidelberg.Embargo Period 12 month

    Increased Systemic Glucose Tolerance with Increased Muscle Glucose Uptake in Transgenic Mice Overexpressing RXRγ in Skeletal Muscle

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    BACKGROUND: Retinoid X receptor (RXR) γ is a nuclear receptor-type transcription factor expressed mostly in skeletal muscle, and regulated by nutritional conditions. Previously, we established transgenic mice overexpressing RXRγ in skeletal muscle (RXRγ mice), which showed lower blood glucose than the control mice. Here we investigated their glucose metabolism. METHODOLOGY/PRINCIPAL FINDINGS: RXRγ mice were subjected to glucose and insulin tolerance tests, and glucose transporter expression levels, hyperinsulinemic-euglycemic clamp and glucose uptake were analyzed. Microarray and bioinformatics analyses were done. The glucose tolerance test revealed higher glucose disposal in RXRγ mice than in control mice, but insulin tolerance test revealed no difference in the insulin-induced hypoglycemic response. In the hyperinsulinemic-euglycemic clamp study, the basal glucose disposal rate was higher in RXRγ mice than in control mice, indicating an insulin-independent increase in glucose uptake. There was no difference in the rate of glucose infusion needed to maintain euglycemia (glucose infusion rate) between the RXRγ and control mice, which is consistent with the result of the insulin tolerance test. Skeletal muscle from RXRγ mice showed increased Glut1 expression, with increased glucose uptake, in an insulin-independent manner. Moreover, we performed in vivo luciferase reporter analysis using Glut1 promoter (Glut1-Luc). Combination of RXRγ and PPARδ resulted in an increase in Glut1-Luc activity in skeletal muscle in vivo. Microarray data showed that RXRγ overexpression increased a diverse set of genes, including glucose metabolism genes, whose promoter contained putative PPAR-binding motifs. CONCLUSIONS/SIGNIFICANCE: Systemic glucose metabolism was increased in transgenic mice overexpressing RXRγ. The enhanced glucose tolerance in RXRγ mice may be mediated at least in part by increased Glut1 in skeletal muscle. These results show the importance of skeletal muscle gene regulation in systemic glucose metabolism. Increasing RXRγ expression may be a novel therapeutic strategy against type 2 diabetes

    Characteristic of GAFCHROMIC XR TYPE T dosimetry film

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    医療の高度化に伴い,近年では長時間のⅩ線透視を行うInterventional Radiology(IVR)手技が頻繁に行われ,副作用としての難治性放射線皮膚障害例の報告が増加している。確定的影響である放射線皮膚障害はしきい値を超えると発症し,線量に依存して障害の程度が重篤となるため,患者被曝線量の測定が重要である。しかし,IVRでは照射部位が多彩で,焦点-皮膚間距離が不安定なため,その測定方法は確立されていない。本研究では,近年IVR等低エネルギー線量測定用フイルムとして開発されたCAFCHROMIC XR TYPE T について性能評価を行い,患者皮膚入射面の被曝線量測定への応用の可能性について検討した。その結果,線量特性,線質特性,ネット値の安定性に良好な特性を示し,臨床に使用可能であったので報告する。In recent years, interventional radiology (IVR) using which uses prolomged fluoroscopy has been performed frequently in clinical radiology. Also, reports of radiation skin injuries whose symptoms occur after IVR has been also increasing. These symptoms will become worse if the radiation induced skin injuries are caused by doses which are above the designated threshold, and the grade of injuries are dependent on dose. Therefore, it is important that patient skin dose is measured correctly. But when perfoming IVR, irradiation is complex pricedure, and there is a measurement error with an unfixed source-to-skin distance. So. in this paper, characteristics of GAFCHROMIC XR TYPE T (which are film for low energy X-rays) are performed. Then, they are decided whether the application to the skin surface incidence dose measurement whoud be posible. From these results usefull data can be obtainned; for exanmpe film characteristics, energy factors and stability of sensivility

    The ASTRO-H X-ray Observatory

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    The joint JAXA/NASA ASTRO-H mission is the sixth in a series of highly successful X-ray missions initiated by the Institute of Space and Astronautical Science (ISAS). ASTRO-H will investigate the physics of the high-energy universe via a suite of four instruments, covering a very wide energy range, from 0.3 keV to 600 keV. These instruments include a high-resolution, high-throughput spectrometer sensitive over 0.3-2 keV with high spectral resolution of Delta E < 7 eV, enabled by a micro-calorimeter array located in the focal plane of thin-foil X-ray optics; hard X-ray imaging spectrometers covering 5-80 keV, located in the focal plane of multilayer-coated, focusing hard X-ray mirrors; a wide-field imaging spectrometer sensitive over 0.4-12 keV, with an X-ray CCD camera in the focal plane of a soft X-ray telescope; and a non-focusing Compton-camera type soft gamma-ray detector, sensitive in the 40-600 keV band. The simultaneous broad bandpass, coupled with high spectral resolution, will enable the pursuit of a wide variety of important science themes.Comment: 22 pages, 17 figures, Proceedings of the SPIE Astronomical Instrumentation "Space Telescopes and Instrumentation 2012: Ultraviolet to Gamma Ray

    The Quiescent Intracluster Medium in the Core of the Perseus Cluster

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    Clusters of galaxies are the most massive gravitationally-bound objects in the Universe and are still forming. They are thus important probes of cosmological parameters and a host of astrophysical processes. Knowledge of the dynamics of the pervasive hot gas, which dominates in mass over stars in a cluster, is a crucial missing ingredient. It can enable new insights into mechanical energy injection by the central supermassive black hole and the use of hydrostatic equilibrium for the determination of cluster masses. X-rays from the core of the Perseus cluster are emitted by the 50 million K diffuse hot plasma filling its gravitational potential well. The Active Galactic Nucleus of the central galaxy NGC1275 is pumping jetted energy into the surrounding intracluster medium, creating buoyant bubbles filled with relativistic plasma. These likely induce motions in the intracluster medium and heat the inner gas preventing runaway radiative cooling; a process known as Active Galactic Nucleus Feedback. Here we report on Hitomi X-ray observations of the Perseus cluster core, which reveal a remarkably quiescent atmosphere where the gas has a line-of-sight velocity dispersion of 164+/-10 km/s in a region 30-60 kpc from the central nucleus. A gradient in the line-of-sight velocity of 150+/-70 km/s is found across the 60 kpc image of the cluster core. Turbulent pressure support in the gas is 4% or less of the thermodynamic pressure, with large scale shear at most doubling that estimate. We infer that total cluster masses determined from hydrostatic equilibrium in the central regions need little correction for turbulent pressure.Comment: 31 pages, 11 Figs, published in Nature July
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