Proceedings of the Japan Academy, Series B
Online ISSN : 1349-2896
Print ISSN : 0386-2208
ISSN-L : 0386-2208
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Reviews
  • Hiroyuki MATSUNAMI
    2020 Volume 96 Issue 7 Pages 235-254
    Published: July 31, 2020
    Released: August 12, 2020
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    Today, the silicon carbide (SiC) semiconductor is becoming the front runner in advanced power electronic devices. This material has been considered to be useful for abrasive powder, refractory bricks as well as ceramic varistors. Big changes have occurred owing to the author’s inspirational idea in 1968 to “make transistors from unusual material”. The current paper starts by describing the history of SiC research involving fundamental studies by the author’s group: unique epitaxial crystal growth techniques, the physical characterization of grown layers and processes for device fabrication. Trials for fabricating SiC power devices and their characteristics conducted until 2004 are precisely described. Recent progress in SiC crystal growth and peripheral techniques for SiC power devices are introduced. Finally, the present progress concerning SiC power devices is introduced together with the implementation of those devices in society.

  • Tadao KAKIZOE
    2020 Volume 96 Issue 7 Pages 255-265
    Published: July 31, 2020
    Released: August 12, 2020
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    More than 90% of bladder cancer is composed of transitional cell carcinoma (TCC), being characterized by the development of multiple tumors in the entire urinary tract over time. When cystectomy is conducted, the urinary tract must be reconstructed by various procedures, which can include an orthotopic neobladder using the patient’s own intestine formed into a spherical shape anastomosed to the urethra. Using this procedure, patients can void urine from their own urethra even after cystectomy. The incidence of subsequent urethral cancer arising after cystectomy is known to be relatively high; however, if patients with a high risk of urethral recurrence are appropriately excluded, a neobladder can be safely provided for patients. Orthotopic neobladder use is reviewed from an oncological viewpoint and the patient’s quality of life after cystectomy for bladder cancer.

  • Akira INOUE
    2020 Volume 96 Issue 7 Pages 266-272
    Published: July 31, 2020
    Released: August 12, 2020
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    The identification of mutations in the epidermal growth factor receptor (EGFR) gene has revolutionized the treatment strategy for non-small cell lung cancer (NSCLC). The effectiveness of individualized treatment using EGFR tyrosine kinase inhibitors (TKIs) for EGFR-mutated NSCLC has mainly been clarified in clinical trials within Japan, and EGFR-TKI monotherapy has been established as the standard first-line treatment for EGFR-mutated NSCLC. Since then, combination regimens involving EGFR-TKI and chemotherapy or anti-angiogenic agents have been developed. Regarding combinations, the NEJ009 study conducted in Japan showed a significant prolongation of progression-free survival and overall survival compared with gefitinib alone. The NEJ009 regimen may be a reasonable option for patients with good performance status in terms of risk–benefit balance. However, further investigation is warranted to improve clinical outcomes in EGFR-mutated NSCLC.

  • Hiroshi HAMADA
    2020 Volume 96 Issue 7 Pages 273-296
    Published: July 31, 2020
    Released: August 12, 2020
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    Although the human body appears superficially symmetrical with regard to the left–right (L-R) axis, most visceral organs are asymmetric in terms of their size, shape, or position. Such morphological asymmetries of visceral organs, which are essential for their proper function, are under the control of a genetic pathway that operates in the developing embryo. In many vertebrates including mammals, the breaking of L-R symmetry occurs at a structure known as the L-R organizer (LRO) located at the midline of the developing embryo. This symmetry breaking is followed by transfer of an active form of the signaling molecule Nodal from the LRO to the lateral plate mesoderm (LPM) on the left side, which results in asymmetric expression of Nodal (a left-side determinant) in the left LPM. Finally, L-R asymmetric morphogenesis of visceral organs is induced by Nodal-Pitx2 signaling. This review will describe our current understanding of the mechanisms that underlie the generation of L-R asymmetry in vertebrates, with a focus on mice.

  • Kazushige OBARA
    2020 Volume 96 Issue 7 Pages 297-315
    Published: July 31, 2020
    Released: August 12, 2020
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    Slow earthquakes are a recently discovered phenomenon that mainly occur updip and downdip of the seismogenic zones of great earthquakes along the subducting plate interface. The spatiotemporal activity of various slow earthquakes occurring in the Nankai subduction zone is characterized by along-strike heterogeneity and along-dip systematic changes. Various slow earthquakes are horizontally distributed at their own depths and along-strike segments can be observed with respect to this distribution downdip of the locked zone; however, slow and great earthquakes occur in the same depth range near the Nankai Trough and Japan Trench axes. The frequently observed spatiotemporal interactions between different slow earthquakes can be attributed to their sensitivity and the stress transfer of the surrounding areas. This stress transfer is expected to extend to the adjacent sections in the seismogenic zone. Therefore, precise monitoring of slow earthquakes is important for future evaluations of great earthquakes, which requires the long-term maintenance and continuous improvement of the high-quality observation networks.

  • Hiroyuki MANO
    2020 Volume 96 Issue 7 Pages 316-321
    Published: July 31, 2020
    Released: August 12, 2020
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    Advances in cancer research have revolutionized the way cancer is diagnosed and treated. Any cancer is now known to be an amalgamation of many subtypes, each carrying its specific cancer-causing gene or oncogene. It is also evident that a given oncogene is often present across a wide range of cancer subtypes, albeit at different frequencies. These lines of information have brought cancer genomic medicine (CGM) to the clinic, where genetic information is used to optimize therapeutic intervention. In 2017, the Expert Meeting for Cancer Genomic Medicine Promotion Consortium in the Ministry of Health, Labour and Welfare (MHLW) of Japan submitted a blueprint for the CGM platform in Japan. Accordingly, the MHLW designated a total of 206 hospitals that conduct cancer gene panel testing under the national health insurance system and established the Center for Cancer Genomics and Advanced Therapeutics to store genomic/clinical information of cancer patients. Since June 2019, the CGM officially started in Japan.

Original Article
  • Yuji SANO, Satoki ONDA, Takanori KAGOSHIMA, Toshihiro MIYAJIMA, Naoto ...
    2020 Volume 96 Issue 7 Pages 322-334
    Published: July 31, 2020
    Released: August 12, 2020
    JOURNALS FREE ACCESS FULL-TEXT HTML

    Here, we report the groundwater oxygen isotope anomalies caused by the 2016 Kumamoto earthquake (MJMA7.3) that occurred in Southwest Japan on April 16, 2016. One hundred and seventeen groundwater samples were collected from a deep well located 3 km to the southeast of the epicenter in Mifune Town, Kumamoto Prefecture; they were drinking water packed in PET bottles and distributed in the area between April 2015 and March 2018. Further, the oxygen and hydrogen isotopes were evaluated via cavity ring-down spectroscopy without performing any pretreatment. An anomalous increase was observed with respect to the δ18O value (up to 0.51‰) soon after the earthquake along with a precursory increase of 0.38‰ in January 2016 before the earthquake. During these periods, there was no noticeable change in the hydrogen isotopic ratios. Rapid crustal deformation related to the earthquake may have enhanced the microfracturing of the aquifer rocks and the production of new surfaces, inducing δ18O enrichment via oxygen isotopic exchange between rock and porewater without changing δ2H.

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