Comparative study of flux pinning, creep and critical currents between YBaCuO crystals with and without Y2BaCuO5 inclusions

In the Y-Ba-Cu-O system, YBa2Cu3O(x) phase is produced by the following peritectic reaction: Y2BaCuO5 + liquid yields 2YBa2Cu3O(x). Through the control of processing conditions and starting compositions, it becomes possible to fabricate large crystals containing fine Y2BaCuO5(211) inclusions. Such crystals exhibit Jc values exceeding 10000 A/sq cm at 77 K and 1T. Recently, researchers developed a novel process which can control the volume fraction of 211 inclusions. Elimination of 211 inclusions is also possible. In this study, researchers prepared YBaCuO crystals with and without 211 inclusions using the novel process, and compared flux pinning, flux creep and critical currents. Magnetic field dependence of Jc for YBaCuO crystals with and with 211 inclusions is shown. It is clear that fine 211 inclusions can contribute to flux pinning. It was also found that flux creep rate could be reduced by increasing flux pinning force. Critical current density estimates based on the conventional flux pinning theory were in good agreement with experimental results

Characterization of a cDNA encoding a precursor of Carassius RFamide, structurally related to a mammalian prolactin-releasing peptide

AbstractWe have characterized the cDNA encoding Carassius RFamide (C-RFa), which is structurally related to mammalian prolactin-releasing peptides (PrRPs), from the brain of the crucian carp. The deduced C-RFa precursor has been shown to comprise 117 amino acids, encoding a single C-RFa sequence. A comparative study of amino acid sequences has revealed that several sequences conserved in preproPrRPs are also found in the C-RFa precursor. Furthermore, the abundant presence of the C-RFa mRNA in the telencephalon, optic tectum, medulla oblongata, and proximal half eye ball was demonstrated by Southern blot analysis of RT-PCR products

Noninvasive quantitative evaluation of viable islet grafts using ¹¹¹In-exendin-4 SPECT/CT

Islet transplantation (IT) is an effective β-cell replacement therapy for patients with type 1 diabetes; however, the lack of methods to detect islet grafts and evaluate their β-cell mass (BCM) has limited the further optimization of IT protocols. Therefore, the development of noninvasive β-cell imaging is required. In this study, we investigated the utility of the ¹¹¹Indium-labeled exendin-4 probe {[Lys12(111In-BnDTPA-Ahx)] exendin-4} (¹¹¹In exendin-4) to evaluate islet graft BCM after intraportal IT. The probe was cultured with various numbers of isolated islets. Streptozotocin-induced diabetic mice were intraportally transplanted with 150 or 400 syngeneic islets. After a 6-week observation following IT, the ex-vivo liver graft uptake of ¹¹¹In-exendin-4 was compared with the liver insulin content. In addition, the in-vivo liver graft uptake of ¹¹¹In exendin-4 using SPECT/CT was compared with that of liver graft BCM measured by a histological method. As a result, probe accumulation was significantly correlated with islet numbers. The ex-vivo liver graft uptake in the 400-islet-transplanted group was significantly higher than that in the control and the 150-islet-transplanted groups, consistent with glycemic control and liver insulin content. In conclusion, in-vivo SPECT/CT displayed liver islet grafts, and uptakes were corroborated by histological liver BCM. ¹¹¹In-exendin-4 SPECT/CT can be used to visualize and evaluate liver islet grafts noninvasively after intraportal IT

Comparative study of flux pinning flux creep and critical currents between YBaCuO crystals with and without Y2BaCuO5 inclusions

In the Y-Ba-Cu-O system YBa2Cu3Ox phase is produced by the following peritectic reaction: Y2BaCuO5 + liquid yields 2YBa2Cu3Ox. Through the control of processing conditions and starting compositions it becomes possible to fabricate large crystals containing fine Y2BaCuO5(211) inclusions. Such crystals exhibit Jc values exceeding 10000 A/sq cm at 77 K and 1T. Recently, researchers developed a novel process which can control the volume fraction of 211 inclusions. Elimination of 211 inclusions is also possible. In this study, researchers prepared YBaCuO crystals with and without 211 inclusions using the novel process and compared flux pinning, flux creep and critical currents. Magnetic field dependence of Jc for YBaCuO crystals with and without 211 inclusions is shown. It is clear that fine 211 inclusions can contribute to flux pinning. It was also found that flux creep rate could be reduced by increasing flux pinning force. Critical current density estimates based on the conventional flux pinning theory were in good agreement with experimental results

Magnetic Field-Induced Strain of Metamagnetic Heusler Alloy Ni41Co9Mn31.5Ga18.5

Ni41Co9Mn31.5Ga18.5 is a re-entrant and metamagnetic Heusler alloy. In order to investigate the magnetic functionality of polycrystalline Ni41Co9Mn31.5Ga18.5, magnetic field-induced strain (MFIS) measurements were performed. A 0.12% MFIS was observed at 340 K and 10 T. Strict MFISs between 330 and 370 K were observed. These magneto-structural variances acted in concert with the metamagnetic property observed by the magnetization measurements and magneto-caloric property observed by the caloric measurements in applied magnetic fields. The MFISs were proportional to the fourth power of the magnetization, and this result is in agreement with Takahashi’s spin fluctuation theory of itinerant electron magnetism. The investigation of time response of the MFIS was performed by means of water-cooled electric magnet, zero magnetic field to 1.66 T in 8.0 s at 354 K. A 2.2×10−4 MFIS was observed, which was 80% of the MFIS in a 60-s mode. This indicates that a high-speed transition has occurred on applying magnetic fields

頸動脈狭窄に対する自己拡張型ステント留置後フォローアップ時のステント径と内腔の検討

Purpose: We examined postoperative stent and lumen expansions after carotid artery stenting (CAS) in patients with carotid artery stenosis. Furthermore, we investigated factors influencing the stent and lumen expansions in a follow-up period. Subjects: 134 cases (128 patients) who underwent CAS and performed follow-up cerebral angiography 12 months after CAS were enrolled into this study. The stenosis rate based on the stent and lumen diameters on follow-up angiography as a percentage of that immediately after CAS was evaluated. Results: Both the stent and lumen diameters were significantly dilated 12 months after CAS (p <0.001). There were no significant stent-type-related differences in the stent expansion rate. In the symptomatic stenosis group, this expansion rate was significantly higher than in the asymptomatic stenosis group (p = 0.02). With respect to the presence or absence of a high signal intensity on time of flight (TOF) magnetic resonance (MR) images, the stent expansion rate was significantly higher in the high signal intensity group (p = 0.006). In patients with a plaque/sternocleidomastoid muscle signal intensity ratio of ≥1.50 on plaque images, it was significantly higher than in those with a value of <1.50 (p = 0.006). However, there were no significant differences in the lumen expansion rate among the groups. Conclusion: Both the stent and vascular lumen were dilated 12 months after CAS. Plaque fragility influenced the stent expansion rate; however, there were no significant factor-related differences in the vascular lumen expansion rate.博士（医学）・乙第1414号・平成30年3月15日©2017 The Editorial Committee of Journal of Neuroendovascular Therapy. All rights reserved. This is an open access article distributed under the terms of Creative Commons Attribution License(CC BY-NC-ND 4.0) https://creativecommons.org/licenses/by-nc-nd/4.0/