11 results on '"Mitsuhiro Azuma"'
Search Results
2. System Development Aiming Efficient Recording of Pedigree Information and Database Construction for Genetic Counseling Clinic
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Takuya, Nagasawa, Mitsuhiro, Azuma, Michihiko, Aki, Masaki, Yamada, Mineko, Ushiama, Noriko, Tanabe, Takeshi, Nakajima, Kokichi, Sugano, Hiromi, Sakamoto, and Teruhiko, Yoshida
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Communication ,Humans ,Genetic Counseling ,Ambulatory Care Facilities ,Pedigree - Abstract
In the collaborative research to support genomic medicine, we aim to improve the efficiency of operation such as prevention of hereditary cancer syndromes. In the present work, we built a prototype system to record a pedigree chart, clinical and genetic information on individuals during a genetic counseling session. In a mock examination, we were able to draw the pedigree chart of four generations in about four minutes and to record necessary information without disrupting conversation with counselees.
- Published
- 2018
3. A Low-Complexity Turbo Equalizer for OFDM Communication Systems
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Mitsuhiro Azuma, Alexander N. Lozhkin, and Tomohiko Taniguchi
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Carrier signal ,Computer Networks and Communications ,Computer science ,Orthogonal frequency-division multiplexing ,business.industry ,Bandwidth (signal processing) ,Equalization (audio) ,Communications system ,Interference (wave propagation) ,Subcarrier ,Turbo equalizer ,Electronic engineering ,Frequency offset ,Electrical and Electronic Engineering ,Telecommunications ,business ,Software ,Data transmission ,Communication channel - Abstract
With the growing demand for mobile communications, multicarrier (MC) schemes are receiving an increasing amount of attention, primarily because they handle frequency selective channels better than ordinary single-carrier schemes. However, despite offering several advantages, MC systems have certain weak points. One is their high sensitivity to interchannel interference (ICI). The influence of Doppler shift and ICI are the focus of this paper. Newly proposed B3G/4G systems are developed for data transmission rates higher than those of the IEEE 801.11 It is then necessary that the bandwidth of the subcarrier be small. Moreover, for a higher carrier frequency and mobile speed, the influence of the Doppler shift will be large; therefore, the influence of ICI becomes severer. Using a Markov chain approach, we synthesized a turbo equalizer (TE) that minimizes ICI when interference affects the arbitrary number M of adjacent subchannels. This approach shows the complexity of the proposed algorithm exhibits linear growth with respect to M and independence with respect to the total number of subchannels in the multicarrier system. The proposed ICI cancellation scheme can also be effective in the case of multiple Doppler frequency offsets. This makes the proposed approach attractive for practical implementations.
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- 2006
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4. Protective effect of taurine on the detachment of cultured cardiac fibroblasts from the substratum induced by calcium depletion
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Takahisa Matsuda, Junichi Azuma, A. Kimura, Kyoko Takahashi, Mitsuhiro Azuma, and S. W. Schaffer
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Taurine ,Myocardium ,Organic Chemistry ,Clinical Biochemistry ,Adhesion ,Fibroblasts ,Biology ,Calcium Channel Blockers ,Biochemistry ,Rats ,Cell biology ,Cell membrane ,chemistry.chemical_compound ,medicine.anatomical_structure ,chemistry ,Cell Adhesion ,medicine ,Animals ,Calcium ,sense organs ,Calcium depletion ,Rats, Wistar ,Incubation ,Cells, Cultured - Abstract
Removal of Ca2+ from the incubation medium of cultured rat cardiac fibroblasts causes cellular morphological changes, such as the formation of blebs, the ballooning of the cell membrane and the detachment from the culture dish. A 24 hr preincubation with 20 mM taurine blocked the Ca2+ depletion-induced detachment of the cardiac fibroblasts. However, taurine treatment did not prevent other morphological changes induced by Ca2+ depletion. The data suggest that taurine plays an important role in cell adhesion in the heart.
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- 2004
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5. Effects of Antisense Oligonucleotides to the Cardiac Na+/Ca2+ Exchanger on Calcium Dynamics in Cultured Cardiac Myocytes
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Jana Huschenbett, Mitsuhiro Azuma, Mary L. Michaelis, Kyoko Takahashi, and Junichi Azuma
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Time Factors ,Biophysics ,Diastole ,Biology ,Biochemistry ,Sodium-Calcium Exchanger ,Calcium dynamics ,Gene expression ,Animals ,Myocyte ,RNA, Messenger ,Rats, Wistar ,Molecular Biology ,Cells, Cultured ,Beating rate ,Cardiac cycle ,Myocardium ,Heart ,Cell Biology ,Oligonucleotides, Antisense ,Molecular biology ,Rats ,Mrna level ,Antisense oligonucleotides ,cardiovascular system ,Calcium - Abstract
The present study was designed to explore the role of the Na + /Ca 2+ exchanger on spontaneous beating of cultured cardiac myocytes. Antisense oligonucleotides (AS) based on the sequence of the cardiac Na + /Ca 2+ exchanger were used to decrease expression of this Ca 2+ transporting protein in cardiac myocytes. An application of AS (10 μM) caused an increase in beating rate of myocytes within 6–24 h. After 24 h of exposure, AS increased the beating rate from an average rate of 77 beats/min in control and sense-treated myocytes to 103 beats/min. Moreover, myocytes treated for 24 h with 10 μM AS exhibited an increase in diastolic [Ca 2+ ] i levels. The antisense treatment also led to a ∼20% decrease in expression of Na + /Ca 2+ exchanger proteins within 6–24 h. Changes in mRNA levels following AS treatment could not be detected within 3- to 24-h periods. The results of these studies suggest that the Na + /Ca 2+ exchanger plays a potentiating role in spontaneous the beating process by regulating [Ca 2+ ] i dynamics and that even a small reduction in the levels of the exchanger protein has marked effects on the handling of [Ca 2+ ] i during the cardiac cycle.
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- 1999
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6. Effect of Taurine on Angiotensin II-Induced Hypertrophy of Neonatal Rat Cardiac Cells
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Kyoko Takahashi, Stephen W. Schaffer, Mitsuhiro Azuma, Akemichi Baba, Junichi Azuma, Isamu Yamamoto, and Koki Taira
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Taurine ,medicine.medical_specialty ,Angiotensin receptor ,Biology ,chemistry.chemical_compound ,Internal medicine ,Renin–angiotensin system ,medicine ,Animals ,Myocyte ,Rats, Wistar ,Genes, Immediate-Early ,Pharmacology ,Hyperplasia ,Angiotensin II receptor type 1 ,DNA synthesis ,Angiotensin II ,Myocardium ,Heart ,Hypertrophy ,Rats ,Endocrinology ,Animals, Newborn ,chemistry ,Cell culture ,Cardiology and Cardiovascular Medicine - Abstract
The effect of taurine on angiotensin II-induced hypertrophy of cultured neonatal rat heart cells (myocytes and nonmyocytes) was examined. Angiotensin II (1-100 nM) alone caused an increase in the rate of protein synthesis of myocytes without changing the rate of DNA synthesis and cell number. It mediated increases in DNA synthesis and cell number in nonmyocytes. Furthermore, at the lower concentration of 1 nM, induced c-fos and c-jun expression in both cultured myocytes and nonmyocytes. Exposure of the cells to taurine (20 mM) in the absence of angiotensin II had no effect on either hyperplastic growth or immediate early response gene expression by the two types of cultured cardiac cells. However, myocytes pretreated for 24 h with 20 mM taurine exhibited reduced responsiveness to angiotensin II (1 nM), resulting in lower levels of angiotensin II-mediated stimulation in protein synthesis, and immediate early response gene expression was attenuated. Similarly, taurine treatment of nonmyocytes reduced the degree of hyperplastic growth (DNA synthesis and cell number) and immediate early response gene expression stimulated by angiotensin II. Finally, taurine partially prevented the increase in intracellular free calcium [Ca 2+ ] i mediated by angiotensin II in cardiac cells. Our results indicate that taurine is an effective inhibitor of angiotensin II action.
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- 1997
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7. Demonstration experiment of millimeter wave multi-gigabit wireless LAN system
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Hiroyuki Ohtsuki, Mitsuhiro Azuma, Atsushi Honda, Satoru Shimizu, Takayuki Umaba, Amane Miura, Masazumi Ueba, and Shoichi Kitazawa
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Computer science ,Orthogonal frequency-division multiplexing ,ComputerSystemsOrganization_COMPUTER-COMMUNICATIONNETWORKS ,Physical layer ,law.invention ,IEEE 802.11 ,Hardware_GENERAL ,law ,PHY ,Gigabit ,Media access control ,Electronic engineering ,Wi-Fi ,Throughput (business) - Abstract
We have developed a new 60-GHz band millimeter wave multi-gigabit wireless local area network (WLAN) system that achieves a throughput of more than 1 Gbps. The developed system consists of high-gain eight-sector antenna, physical layer (PHY) for orthogonal frequency multiple access (OFDM) modulation/demodulation, and media access control (MAC) for time and space resource control on point to multi-point (P-MP) communication. The performance of the developed system was evaluated in a room environment. As a result, we confirmed that developed system achieves a high throughput, which exceeds considerably that of current microwave-band WLAN systems based on IEEE802.11.
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- 2009
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8. A study of speech scramblers using the transmultiplexer technique
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Naoya Torii, Mitsuhiro Azuma, Takayuki Hasebe, and Ryota Akiyama
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Signal processing ,Filter design ,Voice activity detection ,Secure communication ,Computer science ,business.industry ,Speech recognition ,Electrical and Electronic Engineering ,Intelligibility (communication) ,business ,Speech processing ,Scrambling ,Group delay and phase delay - Abstract
This paper considers a scrambling technique for an analog voice signal, and proposes a band-split scrambling method applying the transmultiplexer technique, which can effectively divide the voice band using a small amount of signal processing. The principles of signal processing and the filter design are presented. By computer simulation, the quality of the decoded speech, the effect of the channel characteristics and security are evaluated. As a result of quantitative evaluation of the quality of the decoded speech, the relation between the quality of the decoded speech and the number of taps is quantitatively evaluated for fixed and variable scramblings. It is seen that the quality of the voice signal is little affected by the channel characteristics, such as group delay distortion, synchronization error and frequency off-set. Thus, the proposed method is seen to be economical, without requiring additional circuitry as used by various kinds of cancellers. As for security, an intelligibility test using numbers was executed, and high security, comparable to or better than the conventional method, is obtained. Thus, the proposed secure communication method is shown to be effective, with excellent performance in the quality of the scrambled decoded speech economy and security.
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- 1991
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9. Taurine attenuates hypertrophy induced by angiotensin II in cultured neonatal rat cardiac myocytes
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Junichi Azuma, Isamu Yamamoto, Kyoko Takahashi, Yuko Ohyabu, Syokei Kim, Hiroshi Iwao, Stephen W. Schaffer, Mitsuhiro Azuma, and Tsuyoshi Fukuda
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Taurine ,medicine.medical_specialty ,Angiotensin receptor ,Cardiomegaly ,chemistry.chemical_compound ,Internal medicine ,Renin–angiotensin system ,medicine ,Animals ,Vasoconstrictor Agents ,RNA, Messenger ,Rats, Wistar ,Protein kinase A ,Protein kinase C ,Cells, Cultured ,Protein Kinase C ,Cell Size ,Pharmacology ,Mitogen-Activated Protein Kinase 1 ,Angiotensin II receptor type 1 ,Mitogen-Activated Protein Kinase 3 ,biology ,Angiotensin II ,Myocardium ,Angiotensin-converting enzyme ,Blotting, Northern ,Rats ,Endocrinology ,chemistry ,biology.protein ,Mitogen-Activated Protein Kinases - Abstract
The effect of taurine on angiotensin II-induced changes in cell morphology and biochemistry of the cultured neonatal cardiomyocyte was examined. Angiotensin II (1-100 nM) alone caused a slow increase in the surface area of the myocyte accompanied by an induction of the expression of atrial natriuretic peptide (ANP) and an upregulation of transforming growth factor beta(1) gene (TGF-beta(1)). The signaling pathway of angiotensin II (1-100 nM) was found to proceed through protein kinase C and the rapid activation of mitogen-activated protein (MAP) kinases. Pretreatment of the myocyte with taurine (20 mM) in the absence of angiotensin II had no visible effect on cell size or growth rate. However, the cells that were pretreated with taurine (20 mM) for 24 h exhibited reduced responsiveness to angiotensin II (100 nM) relative to surface cell area enlargement and the upregulation of the late and growth factor genes(ANP, TGF-beta(1)). Angiotensin II-mediated activation of the MAP kinases (extracellular signal-regulated protein kinase 1/2: ERK1/2) was not blocked by taurine. Taurine reduced the phosphorylation of a 29-kDa protein, a reaction which was enhanced by angiotensin II and appears to involve protein kinase C step. The results indicate that taurine is an effective inhibitor of certain aspects of angiotensin II action.
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- 2000
10. Taurine Improves Angiotensin II-Induced Hypertrophy of Cultured Neonatal Rat Heart Cells
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Kyoko Takahahsi, Akemichi Baba, Stephen W. Schaffer, Junichi Azuma, and Mitsuhiro Azuma
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medicine.medical_specialty ,Taurine ,DNA synthesis ,Stimulation ,Angiotensin II ,Muscle hypertrophy ,chemistry.chemical_compound ,Endocrinology ,chemistry ,Internal medicine ,Renin–angiotensin system ,medicine ,Protein biosynthesis ,Myocyte - Abstract
The effect of taurine on angiotensin II-induced hypertrophy of cultured neonatal rat heart cells (myocytes and nonmyocytes) was examined. Angiotensin II (1–100 nM) alone caused an increase in the rate of protein synthesis and the surface area of myocytes without altering the rate of DNA synthesis or cell number. It also mediated an increase in DNA synthesis and in cell number of nonmyocytes. Exposure of the cells to taurine (20 mM) in the absence of angiotensin II had no effect on either hyperplastic growth or hypertrophy of the two types of cultured cardiac cells. However, myocytes pretreated with 20 mM taurine exhibited reduced responsiveness to angiotensin II. Following a 24 hr pretreatment with 20 mM taurine, the stimulation in protein synthesis by angiotensin II (1 nM) was significantly suppressed. Similarly, taurine treatment of nonmyocytes reduced the degree of angiotensin II-induced promotion of hyperplastic growth (DNA synthesis and cell number). Finally, taurine partially prevented the rise in [Ca2+]i mediated by angiotensin II in cardiac cells.
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- 1998
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11. Secret speech equipment
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Fumio Amano, Naoya Torii, Mitsuhiro Azuma, and Ryota Akiyama
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Acoustics and Ultrasonics ,Carrier system ,business.industry ,Computer science ,Speech processing ,Signal ,Multiplexing ,Radio spectrum ,Signal multiplexing ,Arts and Humanities (miscellaneous) ,Hardware_GENERAL ,business ,Computer hardware ,Digital signal processing ,Computer Science::Information Theory - Abstract
Disclosed is a secret speech equipment for ensuring the secrecy of an analog voice signal, and used in voice communication systems such as an analog telephone and mobile radio. The equipment comprises a sub-band signal generating unit for treating input digital samples as frequency-multiplexed signals of voice spectra, to split the frequency-multiplexed signals into a plurality of frequency bands, and thus obtain sub-band signals of the frequency bands, a sub-band signal permutating unit for permuting the sequence of the sub-band signals, and a sub-band signal multiplexing unit for multiplexing the permutated sub-band signals.
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- 1992
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