Yasuo Ogawa | Tokyo Institute of Technology (original) (raw)
Papers by Yasuo Ogawa
Japan Geoscience Union, Mar 10, 2017
Japan Geoscience Union, Mar 14, 2018
Bulletin of the Volcanological Society of Japan, 2013
Title Shallow Resistivity Structure of Sakurajima Volcano Revealed by Audio-frequency Magnetotell... more Title Shallow Resistivity Structure of Sakurajima Volcano Revealed by Audio-frequency Magnetotellurics Author(s) KANDA, Wataru; YAMAZAKI, Tomoya; OGAWA, Yasuo; HASHIMOTO, Takeshi; SAKANAKA, Shin�ya; AIZAWA, Koki; TAKAKURA, Shinichi; KOYAMA, Takao; YAMADA, Kenta; KOBAYASHI, Tsukasa; KOMORI, Shogo Citation BULLETIN OF THE VOLCANOLOGICAL SOCIETY OF JAPAN, 58(1): 251-267 Issue Date 2013 Doc URL http://hdl.handle.net/2115/67563 Type article File Information Bull. Volcanol. Soc. Japan58-1_251-267.pdf
Journal of geomagnetism and geoelectricity, 1987
Zisin (Journal of the Seismological Society of Japan. 2nd ser.), 2005
American Journal of Physiology-Cell Physiology, 2000
We examined the effect of low concentrations of H2O2on the Ca2+-release channel/ryanodine recepto... more We examined the effect of low concentrations of H2O2on the Ca2+-release channel/ryanodine receptor (RyR) to determine if H2O2plays a physiological role in skeletal muscle function. Sarcoplasmic reticulum vesicles from frog skeletal muscle and type 1 RyRs (RyR1) purified from rabbit skeletal muscle were incorporated into lipid bilayers. Channel activity of the frog RyR was not affected by application of 4.4 mM (0.02%) ethanol. Open probability ( Po) of such ethanol-treated RyR channels was markedly increased on subsequent addition of 10 μM H2O2. Increase of H2O2to 100 μM caused a further increase in channel activity. Application of 4.4 mM ethanol to 10 μM H2O2-treated RyRs activated channel activity. Exposure to 10 or 100 μM H2O2alone, however, failed to increase Po. Synergistic action of ethanol and H2O2was also observed on the purified RyR1 channel, which was free from FK506 binding protein (FKBP12). H2O2at 100–500 μM had no effect on purified channel activity. Application of FKBP1...
The Journal of Biochemistry, 1980
We examined the effects of P1,P5-di(adenosine-5')pentaphosphate (Ap5A), a potent inhibito... more We examined the effects of P1,P5-di(adenosine-5')pentaphosphate (Ap5A), a potent inhibitor of adenylate kinase, on fragmented sarcoplasmic reticulum (FSR) obtained from bullfrog skeletal muscle in view of the possible usefulness of the nucleotide in experiments with FSR to avoid complications due to contaminating adenylate kinase. Ap5A itself does not cause Ca uptake in the place of ATP. It inhibited adenylate kinase activity without affecting the Ca-ATPase or Ca uptake activity of FSR. The observed effect was a competitive inhibition of basic ATPase activity of the light fraction of FSR. Therefore, P1,P5-di(adenosine-5')pentaphosphate represents an extremely useful tool in experiments wth fragmented sarcoplasmic reticulum, such as studies of H+ movement accompanying Ca movement, ATP-ADP exchange reaction, and calorimetry of the Ca uptake process. A rather high concentration (50 muM or more) of Ap5A is required for complete inhibition of adenylate kinase. Further, we detected 1.3-2.8 nmol of (ATP + ADP), 2-4 nmol of Pi, and unidentified metal(s) in 50 nmol of Ap5A, and Ap5A is more labile to acid and molybdate than ATP.
The Journal of Biochemistry, 1989
To clarify the biological role of phosphoinositides including inositol trisphosphate (IP3) in the... more To clarify the biological role of phosphoinositides including inositol trisphosphate (IP3) in the skeletal muscle, we examined the Ca-releasing action on the heavy fraction of sarcoplasmic reticulum (HFSR) from bullfrog skeletal muscle of IP3, phosphatidylinositol monophosphate (PIP), phosphatidylinositol 4,5-bisphosphate (PIP2), and glycerophosphoinositol 4,5-bisphosphate (GPIP2). Only PIP2 caused dose-dependent Ca release. IP3 (up to 55 microM), PIP (up to 37 microM), and GPIP2 (up to 33 microM) were ineffective. The PIP2-induced Ca release is due to the direct action of PIP2, but not its metabolite(s). The properties of the PIP2-induced Ca release are unique and cannot be accounted for by the Ca release mechanisms already reported, such as Ca2+-induced, ionic substitution-induced, or IP3-induced Ca release. The rate of the PIP2-induced Ca release, however, is so slow that it may have no physiological relevance unless stimulating factors or agents exist.
The Journal of Biochemistry, 1980
1. Measurements were made of heat production and proton release during ATP hydrol-ysis by fragmen... more 1. Measurements were made of heat production and proton release during ATP hydrol-ysis by fragmented sarcoplasmic reticulum (FSR) prepared from bullfrog and rabbit skeletal muscle. A microcalorimeter with an improved time resolution was used (Kodma, T. &
SPIE Proceedings, 2003
In this paper we studied about optical and millimeter radio wave cross-link for formation flight ... more In this paper we studied about optical and millimeter radio wave cross-link for formation flight communication satellite system in a geostationary orbit. In formation flight system, since the distance among the satellites becomes short compared with the conventional inter satellite comunication link, the size and the weight of the communication system can be reduced. If the high data rate cross-link among the satellites which is equal to the whole transponder bandwidth can be established, the functionally distributed communications satellite system can be constructed. Then, by exchanging a part of the satellite system without the physical contact, in other words, by exchange some old satellites and new ones, the fully reconfigurable and long lifetime (from the point of the function) satellite communication system which can follow the paradigm shift in the terrestrial communications technology can be realize. On the other hand, however, since the maximum of relative angle error among two satellites is enlarged, the tracking becomes difficult. In this study, it turns the electric power which is gotten from the shortening the distance to making beam width large. Here, we examine communication among two satellites (10Km distance) where the data rate is 1Gbps.
Equilibrium Research, 2014
Japan Geoscience Union, Mar 10, 2017
Japan Geoscience Union, Mar 14, 2018
Bulletin of the Volcanological Society of Japan, 2013
Title Shallow Resistivity Structure of Sakurajima Volcano Revealed by Audio-frequency Magnetotell... more Title Shallow Resistivity Structure of Sakurajima Volcano Revealed by Audio-frequency Magnetotellurics Author(s) KANDA, Wataru; YAMAZAKI, Tomoya; OGAWA, Yasuo; HASHIMOTO, Takeshi; SAKANAKA, Shin�ya; AIZAWA, Koki; TAKAKURA, Shinichi; KOYAMA, Takao; YAMADA, Kenta; KOBAYASHI, Tsukasa; KOMORI, Shogo Citation BULLETIN OF THE VOLCANOLOGICAL SOCIETY OF JAPAN, 58(1): 251-267 Issue Date 2013 Doc URL http://hdl.handle.net/2115/67563 Type article File Information Bull. Volcanol. Soc. Japan58-1_251-267.pdf
Journal of geomagnetism and geoelectricity, 1987
Zisin (Journal of the Seismological Society of Japan. 2nd ser.), 2005
American Journal of Physiology-Cell Physiology, 2000
We examined the effect of low concentrations of H2O2on the Ca2+-release channel/ryanodine recepto... more We examined the effect of low concentrations of H2O2on the Ca2+-release channel/ryanodine receptor (RyR) to determine if H2O2plays a physiological role in skeletal muscle function. Sarcoplasmic reticulum vesicles from frog skeletal muscle and type 1 RyRs (RyR1) purified from rabbit skeletal muscle were incorporated into lipid bilayers. Channel activity of the frog RyR was not affected by application of 4.4 mM (0.02%) ethanol. Open probability ( Po) of such ethanol-treated RyR channels was markedly increased on subsequent addition of 10 μM H2O2. Increase of H2O2to 100 μM caused a further increase in channel activity. Application of 4.4 mM ethanol to 10 μM H2O2-treated RyRs activated channel activity. Exposure to 10 or 100 μM H2O2alone, however, failed to increase Po. Synergistic action of ethanol and H2O2was also observed on the purified RyR1 channel, which was free from FK506 binding protein (FKBP12). H2O2at 100–500 μM had no effect on purified channel activity. Application of FKBP1...
The Journal of Biochemistry, 1980
We examined the effects of P1,P5-di(adenosine-5')pentaphosphate (Ap5A), a potent inhibito... more We examined the effects of P1,P5-di(adenosine-5')pentaphosphate (Ap5A), a potent inhibitor of adenylate kinase, on fragmented sarcoplasmic reticulum (FSR) obtained from bullfrog skeletal muscle in view of the possible usefulness of the nucleotide in experiments with FSR to avoid complications due to contaminating adenylate kinase. Ap5A itself does not cause Ca uptake in the place of ATP. It inhibited adenylate kinase activity without affecting the Ca-ATPase or Ca uptake activity of FSR. The observed effect was a competitive inhibition of basic ATPase activity of the light fraction of FSR. Therefore, P1,P5-di(adenosine-5')pentaphosphate represents an extremely useful tool in experiments wth fragmented sarcoplasmic reticulum, such as studies of H+ movement accompanying Ca movement, ATP-ADP exchange reaction, and calorimetry of the Ca uptake process. A rather high concentration (50 muM or more) of Ap5A is required for complete inhibition of adenylate kinase. Further, we detected 1.3-2.8 nmol of (ATP + ADP), 2-4 nmol of Pi, and unidentified metal(s) in 50 nmol of Ap5A, and Ap5A is more labile to acid and molybdate than ATP.
The Journal of Biochemistry, 1989
To clarify the biological role of phosphoinositides including inositol trisphosphate (IP3) in the... more To clarify the biological role of phosphoinositides including inositol trisphosphate (IP3) in the skeletal muscle, we examined the Ca-releasing action on the heavy fraction of sarcoplasmic reticulum (HFSR) from bullfrog skeletal muscle of IP3, phosphatidylinositol monophosphate (PIP), phosphatidylinositol 4,5-bisphosphate (PIP2), and glycerophosphoinositol 4,5-bisphosphate (GPIP2). Only PIP2 caused dose-dependent Ca release. IP3 (up to 55 microM), PIP (up to 37 microM), and GPIP2 (up to 33 microM) were ineffective. The PIP2-induced Ca release is due to the direct action of PIP2, but not its metabolite(s). The properties of the PIP2-induced Ca release are unique and cannot be accounted for by the Ca release mechanisms already reported, such as Ca2+-induced, ionic substitution-induced, or IP3-induced Ca release. The rate of the PIP2-induced Ca release, however, is so slow that it may have no physiological relevance unless stimulating factors or agents exist.
The Journal of Biochemistry, 1980
1. Measurements were made of heat production and proton release during ATP hydrol-ysis by fragmen... more 1. Measurements were made of heat production and proton release during ATP hydrol-ysis by fragmented sarcoplasmic reticulum (FSR) prepared from bullfrog and rabbit skeletal muscle. A microcalorimeter with an improved time resolution was used (Kodma, T. &
SPIE Proceedings, 2003
In this paper we studied about optical and millimeter radio wave cross-link for formation flight ... more In this paper we studied about optical and millimeter radio wave cross-link for formation flight communication satellite system in a geostationary orbit. In formation flight system, since the distance among the satellites becomes short compared with the conventional inter satellite comunication link, the size and the weight of the communication system can be reduced. If the high data rate cross-link among the satellites which is equal to the whole transponder bandwidth can be established, the functionally distributed communications satellite system can be constructed. Then, by exchanging a part of the satellite system without the physical contact, in other words, by exchange some old satellites and new ones, the fully reconfigurable and long lifetime (from the point of the function) satellite communication system which can follow the paradigm shift in the terrestrial communications technology can be realize. On the other hand, however, since the maximum of relative angle error among two satellites is enlarged, the tracking becomes difficult. In this study, it turns the electric power which is gotten from the shortening the distance to making beam width large. Here, we examine communication among two satellites (10Km distance) where the data rate is 1Gbps.
Equilibrium Research, 2014