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Author

Hiroshi Yoshida

Other affiliations: Toshiba
Bio: Hiroshi Yoshida is an academic researcher from Tohoku University. The author has contributed to research in topics: Signal & Amplifier. The author has an hindex of 31, co-authored 219 publications receiving 3698 citations. Previous affiliations of Hiroshi Yoshida include Toshiba.


Papers
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Journal ArticleDOI
TL;DR: In this article, the authors presented a 950-MHz wireless power transmission system and a high-sensitivity rectifier circuit for ubiquitous sensor network tags, which offers a battery-life-free sensor tag by recharging the output power of a base station into a secondary battery implemented with the tag.
Abstract: This paper presents a 950-MHz wireless power transmission system and a high-sensitivity rectifier circuit for ubiquitous sensor network tags. The wireless power transmission offers a battery-life-free sensor tag by recharging the output power of a base station into a secondary battery implemented with the tag. For realizing the system, a high-sensitivity rectifier with dynamic gate-drain biasing has been developed in a 0.3-/spl mu/m CMOS process. The measurement results show that the proposed rectifier can recharge a 1.2-V secondary battery over -14-dBm input RF power at a power conversion efficiency of 1.2%. In the proposed wireless system, this sensitivity corresponds to 10-m distance communication at 4-W output power from a base station.

414 citations

Journal ArticleDOI
TL;DR: New cyclotetrapeptides, trapoxins A and B were isolated from the culture broth of Helicoma ambiens RF-1023 and exhibit detransformation activities against v-sis oncogene-transformed NIH3T3 cells (sis/NIH 3T3) as antitumor agents.
Abstract: New cyclotetrapeptides, trapoxins A and B were isolated from the culture broth of Helicoma ambiens RF-1023. These compounds exhibit detransformation activities against v-sis oncogene-transformed NIH3T3 cells (sis/NIH3T3) as antitumor agents. The structures were found to be new cyclotetrapeptides, cyclo[(S)-phenylalanyl-(S)-phenylalanyl-(R)-pipecolinyl- (2S,9S)-2-amino-8-oxo-9,10-epoxydecanoyl-] for trapoxin A and cyclo[(S)-phenylalanyl-(S)-phenylalanyl-(R)-prolyl-2- amino-8-oxo-9,10-epoxydecanoyl-] for trapoxin B, by X-ray analysis, mass spectrometric, NMR and chemical studies.

183 citations

Patent
Tomoya Horiguchi1, Hiroshi Yoshida1, Tazuko Tomioka1, Katsuya Nonin1, Ren Sakata1 
27 Apr 2007
TL;DR: In this article, a cognitive radio system includes a state detecting device that scans a frequency band allocated to another radio system than the CR system to detect a first use state of the frequency band; a first server including a first gathering unit that receives first information relating to the first use-state and a second gathering unit; a second server that stores a second use-State of the spectrum allocated to the other radio system; and a notifying unit that notifies a CR system of information of an available channel based on the first information and the second information.
Abstract: A cognitive radio system includes: a state detecting device that scans a frequency band allocated to another radio system than the cognitive radio system to detect a first use-state of the frequency band; a first server including a first gathering unit that receives first information relating to the first use-state and a second gathering unit; a second server that stores a second use-state of the frequency band allocated to the other radio system, the second server configured to provide second information relating to the second use-state to the second gathering unit; and a notifying unit that notifies a terminal device in the cognitive radio system of information of an available channel based on the first information and the second information.

147 citations

Journal ArticleDOI
TL;DR: CSF-tau and CSF-A beta(1-42) must be used as two distinct biomarkers that should be applied appropriately in clinical settings to help in detecting MCI subjects who are predicted to develop AD.

102 citations

Journal ArticleDOI
TL;DR: Preoperative carbohydrate antigen (CA) 19-9, intrahepatic metastasis, and nodal involvement were the significant independent predictors of poor prognosis by multivariate analysis.
Abstract: The aim of this study was to clarify the prognostic factors of intrahepatic cholangiocarcinoma (ICC) following hepatectomy and to examine the impact of lymph node metastasis on survival. This study was therefore carried out as a Project Study of the Japanese Society of Hepato-Biliary-Pancreatic Surgery. Three hundred and forty-one patients who underwent hepatectomy for ICC between 1995 and 2004 at the 9 institutions of the Medical University Hospitals were analyzed retrospectively. Multivariate regression analyses and a Kaplan–Meyer analysis were performed to identify prognostic factors. Pathological lymph node metastasis was one of the significant factors affecting overall survival (hazard ratio 2.10, p < 0.001) based on the multivariate analysis. Among the patients who underwent extended lymphadenectomy beyond the hepatoduodenal ligament, the median survival of 121 patients with nodal involvement was 12.2 months. Only seven patients with nodal involvement have survived for more than 4 years. In the present study, preoperative carbohydrate antigen (CA) 19-9, intrahepatic metastasis, and nodal involvement were the significant independent predictors of poor prognosis by multivariate analysis. Further prospective studies may thus be needed to confirm these findings, because this study has a limitation in that it was a retrospective study with multicenter data collection.

100 citations


Cited by
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Journal ArticleDOI
TL;DR: A review of the information gathered on cellulose structure over the last few decades can be found in this paper, where the authors attempt to bring together basic and complex information which has been gathered on the structure of native cellulose.
Abstract: This article attempts to bring together basic and complex information which has been gathered on cellulose structure, principally that of native cellulose, over the last few decades. Even though advances have been made in the field of crystallography, powder crystallography cannot yield a definitive cellulose structure and single crystal diffraction is not possible due to the lack of suitable crystals. Knowledge obtained on the biosynthesis of native cellulose and on the polymorphy of cellulose and its derivatives help our understanding of ultrastructure. Many inconsistencies between early crystallographic studies of native cellulose have been clarified by the discovery that two polymorphs (α and β) of cellulose I exist. Models of the possible ultrastructural arrangements within native cellulose have been put forward over the decades; with advancement in technology, computer simulations of small and large systems are being created to test the viability of these ultrastructural models. It is hoped that this review will aid in the understanding of the complexity and uncertainties that still exist in this subject

1,460 citations

Journal ArticleDOI
TL;DR: The CSF biomarkers total tau protein, phosphorylated tauprotein, and the 42 amino-acid residue form of amyloid-beta may, if put in the right clinical context, prove to have high enough diagnostic accuracy to meet the challenge of identifying incipient AD in patients with MCI.
Abstract: Summary Early diagnosis of Alzheimer's disease (AD) is needed to initiate symptomatic treatment with acetylcholinesterase inhibitors, and will be of even greater significance if drugs aimed at slowing down the degenerative process, such as vaccination regimes and β-secretase and γ-secretase inhibitors, prove to affect AD pathology and to have clinical effect. However, there is no clinical method to determine in which patients mild cognitive impairment (MCI) will progress to AD with dementia, and in which patients MCI is benign. Hence, there is a great clinical need for biomarkers to identify incipient AD in patients with MCI. The CSF biomarkers total tau protein, phosphorylated tau protein, and the 42 amino-acid residue form of amyloid-β may, if put in the right clinical context, prove to have high enough diagnostic accuracy to meet this challenge.

1,222 citations

Journal ArticleDOI
TL;DR: It was concluded that adenosine triphosphate was activating the enzyme in a fashion functionally distinct from its action as a phosphate donor, since the concentration of adenosines triph phosphate required for activation was much higher than that required for phosphorylation.

809 citations