著者

Masayuki Konishi Masaki Takahashi Naoya Endo Shigeharu Numao Shun Takagi Masashi Miyashita Taishi Midorikawa Katsuhiko Suzuki Shizuo Sakamoto

出版者

一般社団法人日本体力医学会

雑誌

The Journal of Physical Fitness and Sports Medicine (ISSN:21868131)

巻号頁・発行日

vol.2, no.1, pp.121-126, 2013-03-25 (Released:2013-04-08)

参考文献数

31

被引用文献数

1 2

---

The aim of this study was to investigate the effects of one night of sleep deprivation on maximal fat oxidation during a graded exercise test. Ten healthy young males underwent two 2-day control and sleep deprivation trials. Participants were allowed normal sleep from 2300 to 0700 for the control trial, whereas they were required to stay awake for 34 h during the sleep deprivation trial. At 1700 on day 2, participants performed a graded exercise test to exhaustion on a treadmill; this allowed us to determine maximal oxygen uptake and maximal fat oxidation. Before and immediately after the graded exercise test, blood samples were collected in order to measure glucose, insulin, free fatty acid, and triglyceride concentrations. Plasma glucose concentrations were significantly higher in the sleep deprivation trial than in the control trial before the graded exercise test. Serum insulin and free fatty acid concentrations were not significantly different between the two trials. Serum triglyceride concentrations were significantly lower in the sleep deprivation trial than in the control trial. The maximal fat oxidation rate, oxygen uptake, and heart rate at maximal fat oxidation intensity, during the graded exercise test, were not significantly different between the two trials. These findings suggest that maximal fat oxidation during graded exercise is unaffected by one night of sleep deprivation.

著者

Masaki Takahashi Katsuhiko Suzuki Hideki Matoba Shizuo Sakamoto Shigeru Obara

出版者

一般社団法人日本体力医学会

雑誌

The Journal of Physical Fitness and Sports Medicine (ISSN:21868131)

巻号頁・発行日

vol.1, no.1, pp.183-189, 2012-05-25 (Released:2012-08-22)

参考文献数

36

被引用文献数

2 7

---

The purpose of this study was to investigate the effects of three different intensities of exercise on oxidative stress and antioxidant capacity. Eight healthy male subjects performed three different intensities of exercise for 20 minutes: (1) 70% anaerobic threshold (AT) (light intensity, LI), (2) 100% AT (moderate intensity, MI), and (3) 130% AT (high intensity, HI) on a cycle ergometer. A control (C) trial was conducted under resting conditions. Blood samples were taken pre-exercise, immediately and 30 min after exercise. In the HI trial only, the concentrations of plasma derivatives of reactive oxygen metabolites (d-ROMs) were significantly higher immediately (P<0.01) and 30 min after exercise (P<0.05) than at pre-exercise. Furthermore, plasma trolox equivalent antioxidant capacity was significantly higher immediately after exercise in the HI trial (P<0.01). And, plasma glutathione peroxidase (GPX) activity was significantly higher immediately after exercise than at pre-exercise in the MI (P<0.05) and HI trials (P<0.01). These data suggest that 20 min of pedaling exercise above the AT level may increase ROS production, while endogenous enzyme activity (especially GPX activity) or non-enzymatic antioxidants may modulate exercise-induced ROS generation. Thus, exercise under the AT level induces very little oxidative stress damage in young people.

著者

Asako Takamasa Katsuhiko Suzuki Yusuke Fukami Tsuyoshi Iizuka Maria Luisa G. Tejada Wataru Fujisaki Yuji Orihashi Takuya Matsumoto

出版者

GEOCHEMICAL SOCIETY OF JAPAN

雑誌

GEOCHEMICAL JOURNAL (ISSN:00167002)

巻号頁・発行日

vol.54, no.3, pp.117-127, 2020 (Released:2020-06-22)

参考文献数

33

被引用文献数

1 5

---

The extinct, relatively short-lived nuclide 182Hf produced 182W as a decay product. Fractionation of Hf-W in the very early Earth led to variations in the 182W/184W ratios of terrestrial rocks; however, because these variations are very small, quantifying 182W/184W ratios requires an extremely precise method. Here, we propose an improved method for highly precise and accurate method for measuring the 182W/184W ratios of terrestrial rocks. Samples were extracted with 4-methyl-2-pentanone and purified by cation and anion exchange chromatography prior to determination of the W isotope ratio by multiple collector inductively-coupled plasma mass spectrometry (MC-ICP-MS) system coupled with a desolvating nebulizer. Sample preparation removed matrix elements (e.g., Hf, Ta, Os, and dimers of Nb and Mo) with masses similar to those of W isotopes, resulting in these elements having a negligible influence on the measured 182W/184W ratios. A W standard solution processed by ion exchange chromatography and/or solvent extraction showed a 183W deficiency, even after mass fractionation correction of the measured isotope data. As reported previously, mass-independent fractionation increases the 182W/184W ratio if the 183W/184W ratio is used to correct for mass fractionation to for better precision in natural samples. However, accurate 182W/184W ratios for a basalt reference material (JB-2) were obtained, even if 183W was used for mass fractionation correction. Our results show that it is also possible to correct for the effects of mass-independent fractionation on the 183W/184W ratio by sample-standard bracketing using a W standard solution subjected to the same preparation procedure used for the samples. A major advantage of the newly developed method is that it requires a smaller amount of sample (0.2–0.3 g; 50–80 ng W for JB-2) compared with that needed for other reported methods (typically 0.7–15 g; 500–1000 ng W). This decrease in sample amount was possible by removing matrix elements from the sample solutions, and cleaning the membrane of the desolvating nebulizer between analyses also contribute to enhancing the W ion beam intensity and to high precision. Analysis of different basalts from the Loihi, Kilauea islands and Ontong Java Plateau with various W isotopic compositions consistent with the previous studies demonstrated the reliability of the method.

著者

Shingo Kato Sanae Sakai Miho Hirai Eiji Tasumi Manabu Nishizawa Katsuhiko Suzuki Ken Takai

出版者

日本微生物生態学会・日本土壌微生物学会

雑誌

Microbes and Environments (ISSN:13426311)

巻号頁・発行日

pp.ME17165, (Released:2018-02-16)

被引用文献数

31

---

Many thermophiles thriving in a natural high-temperature environment remain uncultivated, and their ecophysiological functions in the biogeochemical cycle remain unclear. In the present study, we performed long-term continuous cultivation at 65°C and 70°C using a microbial mat sample, collected from a subsurface geothermal stream, as the inoculum, and reconstructed the whole genome of the maintained populations using metagenomics. Some metagenome-assembled genomes (MAGs), affiliated into phylum-level bacterial and archaeal clades without cultivated representatives, contained genes involved in nitrogen metabolism including nitrification and denitrification. Our results show genetic components and their potential interactions for the biogeochemical nitrogen cycle in a subsurface geothermal environment.