Kieran Egan, Maureen Stout, and Keiichi Takaya (Eds.) Teaching and Learning Outside the Box: Inspiring Imagination Across the Curriculum. New York: Teachers College Press, 2007.

( Keiichi Takaya ) 경북대학교 중등교육연구소 2018 Asia Pacific Journal of Educational Research Vol.1 No.2

Effect of the COVID-19 pandemic lockdown on the physique of school-age children in Japan

Takaya Junji,Higashino Hirohiko,Takaya Ryuzo,Sakaguchi Hiromi,Tanoue Jitsuo,Higashide Takashi,Moriguchi Hisako,Nakao Masatoshi,Takai Yasuyuki 대한소아내분비학회 2023 Annals of Pediatirc Endocrinology & Metabolism Vol.28 No.2

Purpose: Schools in Japan were closed nationwide from March to May 2020 because of the coronavirus disease 2019 (COVID-19) pandemic. Many suspect that this school closure affected children’s mental and physical health. We investigated changes in school-age children’s physiques to determine the effects of the COVID-19 lockdown and restrictions on their health. Methods: Data were extracted from a database of school physical examinations in Osaka elementary and junior high schools for 4 consecutive years from 2018 to 2021. The following characteristics were analyzed: short stature, tall stature, underweight, mild obesity, middle grade obesity, and severe obesity. The paired Student t-test was used to compare school examination data in the prepandemic period (2018–2019), pandemic lockdown (2019–2020), and post-lockdown period (2020–2021). Results: Obesity rates in elementary school students aged 6–12 years, particularly in boys, were significantly higher during the lockdown than they were in 2019. After the pandemic, the tall stature rate continued to rise, while rates of short stature and underweight decreased in both sexes in 2020. In junior high school students aged 12–15 years, rates of obesity and underweight tended to decrease in 2020. However, these rates rebounded and rose in 2021 when the lockdown was lifted. Conclusion: During the COVID-19 pandemic lockdown, elementary school students gained weight, while junior high school students lost weight. The lockdown that was implemented during the COVID-19 pandemic had an unfavorable effect on weight gain, particularly in young school-age children.

A high efficient class-E amplifier with switchable damper

Takaya Yamazato,Duk-Kyu Park,Dong-Heon Lee,Ji-Yeon Kim,Sang-Hyun Chun,Jong-Heon Kim 한국콘텐츠학회 2008 ICCC International Digital Design Invitation Exhib Vol.2008 No.12

Study on Single-phase Photovoltaic Power Generation System with Power Decoupling and Generation Control Functions

Takaya Sekiguchi,Toshihisa Shimizu 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5

In photovoltaic (PV) power generation systems, extant studies which focused on either a generation control circuit (GCC) to prevent power reduction caused by a partial shadow or an active power decoupling method (APD) to reduce power pulsation with twice the utility frequency have been reported from various authors. However, to the best of the authors’ knowledge, only a few studies examine PV inverters in which both GCC and APD functions are installed. In this paper, a utility interactive PV inverter equipped with GCC and APD functions is proposed.

Brown preadipocyte transplantation locally ameliorates obesity

Takaya, Kento,Matsuda, Naruhito,Asou, Toru,Kishi, Kazuo Korean Society of Plastic and Reconstructive Surge 2021 Archives of Plastic Surgery Vol.48 No.4

Background Brown adipose tissue (BAT) is a potential target for anti-obesity treatments. Previous studies have shown that BAT activation causes an acute metabolic boost and reduces adiposity. Furthermore, BAT and BAT-derived cell transplantation reportedly help treat obesity by regulating glucose and fatty acid metabolism. However, since BAT transplantation leads to whole-body weight loss, we speculated that earlier approaches cause a generalized and unnecessary fat tissue loss, including in breast and hip tissues. Methods We transplanted white adipose tissue-derived or BAT-derived preadipocytes prepared from C57BL/6 mice into one side of the inguinal fat pads of an obese mouse model (db/db mice) to examine whether it would cause fat loss at the peri-transplant site (n=5 each). The same volume of phosphate-buffered saline was injected as a control on the other side. Six weeks after transplantation, the inguinal fat pad was excised and weighed. We also measured the concentrations of glucose, triglycerides, fatty acids, and total cholesterol in the peripheral blood. Results BAT-derived preadipocytes showed abundant mitochondria and high levels of mitochondrial membrane uncoupling protein 1 expression, both in vivo and in vitro, with a remarkable reduction in weight of the inguinal fat pad after transplantation (0.17±0.12 g, P=0.043). Only free fatty acid levels tended to decrease in the BAT-transplanted group, but the difference was not significant (P=0.11). Conclusions Our results suggest that brown adipocytes drive fat degradation around the transplantation site. Thus, local transplantation of BAT-derived preadipocytes may be useful for treating obesity, as well as in cosmetic treatments.

Donor unit effect on DPP based organic field-effect transistor performance

Takaya, Tomotsugu,Mamo, Melaku Dereje,Karakawa, Makoto,Noh, Yong-Young Applied Science Publishers 2018 Dyes and pigments Vol.158 No.-

<P><B>Abstract</B></P> <P>We report diketopyrrolopyrrole (DPP) based copolymers, poly (diketopyrrolopyrrole-cyclopentadithiophene) (PDPPTT-CPDT) and poly(diketopyrrolopyrrolebenzo[1,2-b:4,5-b’]dithiophene) (PDPPTT-BDT) to investigate donor unit structure effects on organic field-effect transistor (OFET) performance. The highest occupied molecular orbital (HOMO) level and copolymer band gap were tuned by introducing different donor units on the acceptor DPP backbone. PDPPTT-BDT OFETs show 10 fold higher hole field-effect mobility, up to 0.08 cm<SUP>2</SUP> V<SUP>−1</SUP> s<SUP>−1</SUP>, than PDPPTT-CPDT OFETs due to better crystallinity and higher HOMO energetic levels. PDPPTT-CPDT and PDPPTT-BDT were operationally stable with negligible threshold voltage shift after cycling.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Two DPP based copolymers with different donor units are reported for OFET application. </LI> <LI> Introduction of different donor units tuned copolymer HOMO/LUMO levels and band gaps. </LI> <LI> Photophysical properties exhibited distinct thin film molecular interactions and crystallinities. </LI> <LI> PDPPTT-BDT exhibited stronger p-type properties with 10-fold higher hole mobility OFETs. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Adaptive Rate Subscriber Loop Data Transmission using Ethernet Interfaces

Takaya.Norifumi,Dodds, David E.,McCrosky, Carl D. 대한전자공학회 1996 APCCAS:Asia Pacific Conference on Circuits And Sys Vol.1 No.1

The increasing demand for Internet and World Wide Web access from the home has stimulated research into finding methods of providing access at rates greater than the 28.8 kb/s offered by current computer modems. Most copper telephone pairs have bandwidth capacities much greater than the 3.4 kHz voice-band. Using this excess bandwidth it is possible to substantially exceed current modem rates. This paper describes an inexpensive and readily deployable network access technology capable of providing bit rates ranging from hundreds of kbs to potentially greater than 1 Mb/s on existing copper telephone lines. The usable bit rate, which varies depending on the length and gauge of the wire, is adaptively determined at system start up. The results of rate adaption testing are presented, as well as the results of throughput testing when TCP is used to provide flow control across the adaptive rate transmission line. It is also shown that current IBM compatible computers are only capable of supporting data rates of slightly more than 1 Mb/s through Ethernet adaptor cards; providing access rates beyond a few Mb/s is currently unnecessary.

Isoindigo benzodifurandione based conjugated polymers for high performance organic field-effect transistors

Takaya, Tomotsugu,Mamo, Melaku Dereje,Karakawa, Makoto,Noh, Yong-Young The Royal Society of Chemistry 2018 Journal of Materials Chemistry C Vol.6 No.29

<P>We report isoindigo based copolymers, poly(isoindigo benzodifurandione-bithiophene-alkoxyl) (PIBDF-BTO) and poly(isoindigo-bithiophene-alkoxyl) (PI-BTO) for high performance organic field-effect transistors (OFETs). PIBDF-BTO was synthesized by introducing strong electron withdrawing BDF into the acceptor isoindigo unit of PI-BTO to deepen the polymer highest occupied molecular orbital and the lowest unoccupied molecular orbital. This modification provided better polymer chain crystallinity and connectivity in thin film through increased intermolecular interactions and larger co-planarity in PIBDF-BTO. X-ray diffraction and atomic force microscopy showed higher crystallinity and well-arranged nano-fibril morphological PIBDF-BTO film compared with PI-BTO film. PIBDF-BTO OFETs showed much higher field effect mobility with well-balanced ambipolar transport with hole and electron mobilities of 0.27 and 0.22 cm<SUP>2</SUP> V<SUP>−1</SUP> s<SUP>−1</SUP> compared to PI-BTO OFETs with hole mobility 0.004 cm<SUP>2</SUP> V<SUP>−1</SUP> s<SUP>−1</SUP> and very low electron mobility. PIBDF-BTO also showed better hole and electron injection properties due to the narrower band gap (0.97 eV) compared to PI-BTO (1.35 eV). PI-BTO and PIBDF-BTO OFETs were operationally stable with negligible threshold voltage shift after continuous cycling measurements.</P>

Mitigation Techniques of Channel Collisions in the TTFR-Based Asynchronous Spectral Phase-Encoded Optical CDMA System

Takaya Miyazawa,Iwao Sasase 한국통신학회 2009 Journal of communications and networks Vol.11 No.1

In this paper, we propose a chip-level detection and a spectral-slice scheme for the tunable-transmitter/fixed-receiver (TTFR)-based asynchronous spectral phase-encoded optical codedivision multiple-access (CDMA) system combined with timeencoding. The chip-level detection can enhance the tolerance of multiple access interference (MAI) because the channel collision does not occur as long as there is at least one weighted position without MAI. Moreover, the spectral-slice scheme can reduce the interference probability because the MAI with the different frequency has no adverse effects on the channel collision rate. As a result, these techniques mitigate channel collisions. We analyze the channel collision rate theoretically, and show that the proposed system can achieve a lower channel collision rate in comparison to both conventional systems with and without the time-encoding method.

23-hydroxyursolic acid causes cell growth-inhibition by inducing caspase-dependent apoptosis in human cervical squamous carcinoma HeLa cells.

Takaya, Makiko,Nomura, Masaaki,Takahashi, Tatsuo,Kondo, Yoko,Lee, Kyung-Tae,Kobayashi, Shinjiro Potamitis Press 2009 Anticancer research Vol.29 No.4

<P>BACKGROUND: There are few reports on the biological activities of 23-hydroxyursolic acid (23-HUA). The mechanism of growth-inhibition induced by 23-HUA, isolated from Cussonia bancoensis, in human cervical squamous carcinoma HeLa cells is hereby investigated. MATERIALS AND METHODS: The growth-inhibitory activity was measured by MTS assay. Caspases activation and expression of apoptosis-related proteins were detected by Western blotting. Apoptotic cells were observed by morphological analysis with Hoechst 33342. RESULTS: 23-HUA inhibited the growth of HeLa cells in a concentration dependent manner. Proteolytically generated fragments of caspase-3, -8 and -9 were observed in HeLa cells treated with 60 microM 23-HUA. The expression of Bcl-X(L), an anti-apoptotic protein, was markedly decreased by 60 microM 23-HUA. Morphological analysis showed that apoptotic changes occurred after treatment with 60 microM 23-HUA, and the changes were inhibited by a pan-caspase inhibitor, Z-VAD-FMK. CONCLUSION: These results indicate that 23-HUA causes potent growth-inhibition by the induction of apoptosis via activation of caspases in HeLa cells.</P>