Tetsu Tanaka

Bio: Tetsu Tanaka is an academic researcher from Tohoku University. The author has contributed to research in topics: Wafer & Chip. The author has an hindex of 38, co-authored 406 publications receiving 10375 citations. Previous affiliations of Tetsu Tanaka include NTT DoCoMo & Tokyo Medical and Dental University.

Optical pickup device

Abstract: The present invention has for its object to provide a compact and simplified optical pickup device which secures sufficient quantity of converged light required for recording and reproducing onto/from respective optical disks, can obtain required imaging magnification of respective optical systems, and does not generate performance degradation at lens shift, when recording or reproduction is performed onto/from optical disks with different base material thickness by plural optical systems of a single optical pickup device. A first light source and second light source which emit light beams with different wavelength corresponding to plural kinds of optical information recording media, a beam splitter as a synthesizing means, a collimator lens as an optical converting means, and an objective lens as a converging means are equipped, and a light path length converting means such as a prism mirror, which is made of material having high refractive index, for lengthening light path length (air reduction length) is provided between the synthesizing means and the converging means in a state where the first light source is located nearer to the optical converting means than a back focus thereof is and the second light source is located farther from the optical converting means than a back focus thereof is, thereby to making the synthesizing means close to the converging means.

Source/drain contact resistance of silicided thin-film SOI MOSFET's

Abstract: We developed a source/drain contact (S/D) resistance model for silicided thin-film SOI MOSFET's, and analyzed its dependence on device parameters considering the variation in the thickness of the silicide and residual SOI layers due to silicidation. The S/D resistance is insensitive to the silicide thickness over a wide range of thicknesses; however, it increases significantly when the silicide thickness is less than one hundredth of initial SOI thickness, and when almost all the SOI layer is silicided. To obtain a low S/D resistance, the specific contact resistance must be reduced, that is, the doping concentration at the silicide-SOI interface must be more than 10/sup 20/ cm/sup -3/. >

Investigation of the effect of in situ annealing of FePt nanodots under high vacuum on the chemical states of Fe and Pt by x-ray photoelectron spectroscopy

Abstract: The chemical states of Fe and Pt in in situ annealed L10 structured FePt nanodots formed by self-assembled nanodot deposition method have been systematically investigated by angle resolved x-ray photoelectron spectroscopy. From the Fe3p and the Pt4f core level x-ray photoelectron (XP) spectra, it is evident that both the Fe and Pt of the nanodots were oxidized in the as-grown state. After the in situ annealing under high vacuum, a peak corresponding to metallic Fe begins to appear, and subsequently the metallic peak fraction increased with the increase in the annealing temperature. In line with this, the peak fraction of the respective oxides is drastically decreased. Irrespective of the annealing temperatures, it is inferred from the intensity of the XP spectrum that the Fe atom of the FePt nanodots is highly prone to oxidation than the Pt atom. Nevertheless, the valence band spectra of the as-grown FePt nanodot film clearly depict the presence of metallic Fe–Pt alloy. We would like to explain the result...

Evaluation of Platinum-Black Stimulus Electrode Array for Electrical Stimulation of Retinal Cells in Retinal Prosthesis System

Abstract: A retinal prosthesis system with a three-dimensionally (3D) stacked LSI chip has been proposed. We fabricated a new implantable stimulus electrode array deposited with Platinum-black (Pt-b) on a polyimide-based flexible printed circuit (FPC) for the electrical stimulation of the retinal cells. Impedance measurement of the Pt-b electrode–electrolyte interface in a saline solution was performed and the Pt-b electrode realized a very low impedance. The power consumption at the electrode array when retinal cells were stimulated by a stimulus current was evaluated. The power consumption of the Pt-b stimulus electrode array was 91% lower than that of a previously fabricated Al stimulus electrode array due to a convexo-concave surface. In the cytotoxicity test (CT), we confirmed that Pt implantation induced no cellular degeneration of the rat retina. In the animal experiments, electrically evoked potential (EEP) was successfully recorded using Japanese white rabbits. These results indicate that electrical stimulation using the Pt-b stimulus electrode array can restore visual sensation.

Pillar-shaped stimulus electrode array for high-efficiency stimulation of fully implantable epiretinal prosthesis

Abstract: We developed a pillar-shaped microelectrode array (MEA) with varying heights for enhancing the spherical conformity of fully implantable epiretinal prosthesis comprising a 3D stacked retinal chip The fabricated MEA is composed of 100 pillar electrodes with heights ranging from 60 to 80 µm The Pt-coated Cu pillar electrode with a surface diameter of 70 µm and a height of 75 µm and the Pt planar electrode with a surface diameter of 70 µm have 246 and 125 kΩ impedances, respectively, at 1 kHz in vitro experiment The pillar electrode shows lower impedance than the planar electrode because of a larger surface area However, to avoid cross-talking between pillar electrodes, we developed a sidewall passivation process of the pillar electrode by using the surface tension of polyimide The impedance of the isolated pillar electrode 116 kΩ at 1 kHz is similar to the impedance of the planar electrode, because they have similar electrode surface areas The pillar-shaped MEA shows a better spherical conformity

Deciphering the biology of Mycobacterium tuberculosis from the complete genome sequence

Abstract: Countless millions of people have died from tuberculosis, a chronic infectious disease caused by the tubercle bacillus. The complete genome sequence of the best-characterized strain of Mycobacterium tuberculosis, H37Rv, has been determined and analysed in order to improve our understanding of the biology of this slow-growing pathogen and to help the conception of new prophylactic and therapeutic interventions. The genome comprises 4,411,529 base pairs, contains around 4,000 genes, and has a very high guanine + cytosine content that is reflected in the biased amino-acid content of the proteins. M. tuberculosis differs radically from other bacteria in that a very large portion of its coding capacity is devoted to the production of enzymes involved in lipogenesis and lipolysis, and to two new families of glycine-rich proteins with a repetitive structure that may represent a source of antigenic variation.

Antiinflammatory Therapy with Canakinumab for Atherosclerotic Disease

Abstract: BackgroundExperimental and clinical data suggest that reducing inflammation without affecting lipid levels may reduce the risk of cardiovascular disease. Yet, the inflammatory hypothesis of atherothrombosis has remained unproved. MethodsWe conducted a randomized, double-blind trial of canakinumab, a therapeutic monoclonal antibody targeting interleukin-1β, involving 10,061 patients with previous myocardial infarction and a high-sensitivity C-reactive protein level of 2 mg or more per liter. The trial compared three doses of canakinumab (50 mg, 150 mg, and 300 mg, administered subcutaneously every 3 months) with placebo. The primary efficacy end point was nonfatal myocardial infarction, nonfatal stroke, or cardiovascular death. ResultsAt 48 months, the median reduction from baseline in the high-sensitivity C-reactive protein level was 26 percentage points greater in the group that received the 50-mg dose of canakinumab, 37 percentage points greater in the 150-mg group, and 41 percentage points greater in t...

Complete genome sequence of Pseudomonas aeruginosa PAO1, an opportunistic pathogen.

Abstract: Pseudomonas aeruginosa is a ubiquitous environmental bacterium that is one of the top three causes of opportunistic human infections. A major factor in its prominence as a pathogen is its intrinsic resistance to antibiotics and disinfectants. Here we report the complete sequence of P. aeruginosa strain PAO1. At 6.3 million base pairs, this is the largest bacterial genome sequenced, and the sequence provides insights into the basis of the versatility and intrinsic drug resistance of P. aeruginosa. Consistent with its larger genome size and environmental adaptability, P. aeruginosa contains the highest proportion of regulatory genes observed for a bacterial genome and a large number of genes involved in the catabolism, transport and efflux of organic compounds as well as four potential chemotaxis systems. We propose that the size and complexity of the P. aeruginosa genome reflect an evolutionary adaptation permitting it to thrive in diverse environments and resist the effects of a variety of antimicrobial substances.