Shunsuke Yoshii

Unconventional upper- and lower-critical fields and normal-state magnetic susceptibility of the superconducting compound Na 0.35 CoO 2 ⋅ 1.3 H 2 O

Magnetic properties of the layered superconductor, Na 0 . 3 5 CoO 2 . 1.3H 2 O have been investigated. From the temperature dependence and field dependence of the magnetization, the superconducting transition temperature, aswell as upper- and lower-critical fields have been estimated to be T C =4.6 K, H C 2 (0)=61.0 T and H C 1 (0)=28.1 Oe, respectively. These values give quite unusual phenomenological parameters, i.e., coherent length, penetration depth and Ginzburg-Landau parameter of Β=2.32 nm, λ=5.68×10 2 nm, and κ≡λ/Β =244, respectively, suggesting an unconventional nature of superconductivity. Additionally, the magnetic susceptibility above T C and the magnetization curve up to 54 T are also reported.

Integrated diagnostic strategy for the invasion depth of early gastric cancer by conventional endoscopy and EUS

BACKGROUND Although conventional endoscopy (CE) and EUS are considered useful for predicting the invasion depth (T-staging) in early gastric cancer (EGC), no effective diagnostic strategy has been established. OBJECTIVE To produce simple CE criteria and to elucidate an efficient diagnostic method by combining CE and EUS for accurate T-staging. DESIGN Single-center retrospective analysis. SETTING Academic university hospital. PATIENTS Consecutive patients with EGC from April 2007 to March 2012 who underwent CE and EUS before treatment. INTERVENTIONS Recorded endoscopic images were independently reviewed by 3 observers. The CE criteria for massive invasion were defined, and their utility and the additional value of EUS were assessed. MAIN OUTCOME MEASUREMENTS The accuracy of CE based on the criteria and the accuracy of EUS. RESULTS Two hundred thirty patients were enrolled: 195 with mucosal cancer or cancer in the submucosa less than 500 μm from the muscularis mucosae and 35 with invasive cancers. Multivariate analysis of the CE findings by 1 observer revealed that an irregular surface and a submucosal tumor-like marginal elevation were significantly associated with massive invasion. The simple CE criteria, consisting of those 2 features, had an overall accuracy of 73% to 82% and no significant differences in the diagnostic yield compared with EUS in all observers. CE accurately revealed mucosal cancer, and EUS efficiently salvaged the lesions that were over-diagnosed by CE. With our strategy, which involved the CE criteria and the optimal use of EUS, the comprehensive accuracy exceeded 85% in each observer. LIMITATIONS Retrospective, single-center study. CONCLUSIONS We demonstrated a practical strategy for T-staging in EGC using simple CE criteria and EUS.

High-field magnetization of TmB4

The magnetization M of single crystalline TmB4 has been investigated in high magnetic fields up to 54 T and shows considerably anisotropic behavior. In the ordered antiferromagnetic state, the M for B ∥ [001] reaches the saturation magnetization Ms at about 4 T accompanying with plateaux at 1/8 Ms and 1/2 Ms. On the other hand, for B ∥ [100] and [110], the 1/2 Ms state and the saturation of Mwere observed at much higher field above 30 T. The results are discussed in relation to the effects of magnetic frustration and the crystalline electric field.

Magnetization and specific heat of a UIrGe single crystal in high magnetic fields

The temperature and field dependence of the magnetization were measured on a single crystal of the antiferromagnet UIrGe in pulsed fields up to 51 T, and the specific heat in steady fields up to 18 T. At low temperatures, metamagnetic transitions are observed at critical fields Bc of 21 T and 14 T, applied along the b- and the c-axis, respectively. At 2 K, the magnetization jumps at Bc are 0.36 μB/U along the b-axis and 0.28 μB/U along the c-axis. The a-axis is the hardest magnetization direction with a weak linear magnetic response. Both along the b- and the c-axis, Bcdecreases with increasing temperature. Consistent with the magnetization, the sharp anomalies observed in the specific-heat obey the same dependence.

p53 functional deficiency in human colon cancer cells promotes fibroblast-mediated angiogenesis and tumor growth

Cancer-associated fibroblasts (CAFs) create a microenvironment that contributes to tumor growth; however, the mechanism by which fibroblasts are phenotypically altered to CAFs remains unclear. Loss or mutation of the tumor suppressor p53 plays a crucial role in cancer progression. Herein, we analyzed how the p53 status of cancer cells affects fibroblasts by investigating the in vivo and in vitro effects of loss of p53 function in cancer cells on phenotypic changes in fibroblasts and subsequent tumor progression in human colon cancer cell lines containing wild-type p53 and in cells with a p53 functional deficiency. The growth of p53-deficient tumors was significantly enhanced in the presence of fibroblasts compared with that of p53-wild-type tumors or p53-deficient tumors without fibroblasts. p53-deficient cancer cells produced reactive oxygen species, which activated fibroblasts to mediate angiogenesis by secreting vascular endothelial growth factor (VEGF) both in vivo and in vitro Activated fibroblasts significantly contributed to tumor progression. Deletion of fibroblast-derived VEGF or treatment with N-acetylcysteine suppressed the growth of p53-deficient xenograft tumors. The growth effect of blocking VEGF secreted from cancer cells was equivalent regardless of p53 functional status. Human colon cancer tissues also showed a significant positive correlation between p53 cancer cell staining activated fibroblasts and microvessel density. These results reveal that fibroblasts were altered by exposure to p53-deficient epithelial cancer cells and contributed to tumor progression by promoting neovascularization. Thus, p53 acts as a modulator of the tumor microenvironment.

Esophageal adenocarcinoma with white opaque substance observed by magnifying endoscopy with narrow band imaging.

White opaque substance (WOS) is observed in the gastric neoplasia of 0‐IIa type using magnifying endoscopy with narrow band imaging (NBI‐ME). Colonic and duodenal neoplasms with WOS have also been reported. Immunohistochemical examination with adipophilin reveals WOS in gastric neoplasms as lipid droplets, and WOS is specific for neoplasm with intestinal or gastrointestinal phenotype. We herein report a case of adenocarcinoma of the esophagogastric junction with WOS. A male patient in his sixties was found by esophagogastroduodenoscopy to have an esophageal elevated lesion. NBI‐ME showed whitish deposits that looked similar to WOS in gastric neoplasms. The patient underwent endoscopic submucosal dissection and the lesion was resected in a single piece. This tumor had diffuse positivity for adipophilin and gastrointestinal phenotype.

Present status and future plan of research in high magnetic fields at KYOKUGEN in Osaka University

After brief introduction of history and facility of the High Magnetic Field Laboratory at KYOKUGEN in Osaka University, we describe our high field and multi-frequency electron spin resonance (ESR) apparatus by utilizing pulsed and superconducting magnets for the fields up to about 60 T. For the ESR measurements in pulsed magnetic fields, several Gunn and backward oscillators, and a far infrared laser are used as millimeter and submillimeter wave sources. In steady magnetic fields up to 16 T, we have utilized a vector network analyzer with extensions which covers the frequencies between 8 and 700 GHz almost continuously. The latter ESR apparatus is used not only dense magnetic materials but also weak ones, such as metalloproteins. Therefore, we have developed high sensitive multi-frequency ESR apparatus. To extend ESR studies further, we are now constructing ESR apparatus for much higher fields up to 70 T and the wide frequency range up to 7 THz. Magnetization and transport measurements are also performed in high magnetic fields up to 70 T and 60 T, respectively and magnetization measurements under high pressure up to 1 GPa. We plan to develop a 50 T wide bore pulsed magnet with the diameter of about 50 mm for the use of high sensitive ESR and high pressure measurements above 1 GPa.

Underwater endoscopic submucosal dissection: a novel resection strategy for early gastric cancer located on the greater curvature of the gastric body

Endoscopic submucosal dissection (ESD) has become a standard therapy for early gastric cancer (EGC); however, ESD for lesions located on the greater curvature of the gastric body remains technically challenging, because of the direction of gravity [1]. Pooled water or blood hinders the field of view and interrupts the electric current. Pooled blood also makes it difficult to identify the bleeding point of a hemorrhage during the procedure. Herein, we present a case of EGC resected using underwater ESD (UESD) [2] to overcome these technical difficulties (Video S1). An 84-year-old man was diagnosed with an EGC on the greater curvature of the gastric body (Fig. 1A). After a circumferential marking, a mucosal incision was made as in conventional ESD. The gastric lumen was then filled with saline using a water jet and the lesion was resected underwater (Fig. 1B-D). We used a bipolar device (Jet B-knife, Zeon Medical Co. Tokyo, Japan), because electrical energy using monopolar devices is dispersed in saline, which has an electrical conductivity higher than that of body tissue. The UESD technique achieved complete en bloc resection without any adverse event (Fig. 2). This is the first report to describe UESD for an EGC. The floating effect of the mucosa and submucosa provides good traction against gravity. Water immersion improves visualization by reducing glare and dirt on the lens; in addition, in the case of hemorrhage the bleeding point is well visualized [3]. UESD can be a useful strategy for EGC located on the greater curvature of the gastric body. I M A G E O F T H E M O N T H

Localized gastric amyloidosis mimicking a submucosal tumor-like gastric cancer

Commentary Even with the advent of the proton pump inhibitor and improvements in medical management, peptic ulcer disease remains an important clinical problem. The relative frequency of various adverse events occurs at a rate of approximately 1% to 2% per ulcer patient per year of follow-up. The most serious adverse events of peptic ulcer disease include hemorrhage, perforation, penetration, and gastric outlet obstruction. In contrast to perforating ulcer, penetrating ulcer erodes into another organ instead of the peritoneal cavity. There are reported cases of gastric ulcers penetrated into the pancreas, spleen, gastrohepatic omentum, biliary tract, liver, greater omentum, mesocolon, colon, pericardium, and vascular structures. Based on a recent guideline from the American Society for Gastrointestinal Endoscopy, endoscopy does not have a therapeutic role in the management of penetrating gastric ulcers. When a penetrating ulcer is diagnosed, it is important to quickly seek surgical consultation.

Magnetization of a Dy2Fe14Si3single crystal in high magnetic fields

The magnetization of a Dy2Fe14Si3 single crystal was measured at 4.2 K in pulsed fields up to 52 T along the principal axes. The compound is a ferrimagnet with TC = 500 K, has a spontaneous magnetic moment of 9 μB(at 4.2 K) and exhibits a very large magnetic anisotropy, 100 being the easy axis. In fields applied along the 100 and 120 axes, field-induced phase transitions are observed at 33 T and at 39 T, respectively. The c-axis magnetization curve crosses the easy-axis curve at 23 T. At higher fields, for all directions, the magnetization continues to increase due to further bending of the sublattice moments.