Publications by authors named "Kohei Mizuno"

19 Publications

  • Page 1 of 1

Effects on cervical vestibular-evoked myogenic potentials of four clinically used head and neck measurement positions in healthy subjects.

Acta Otolaryngol 2021 Aug 27;141(8):729-735. Epub 2021 Jul 27.

Division of Hearing and Balance Research, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Tokyo, Japan.

Background: The most reliable head and neck position for cervical vestibular-evoked myogenic potentials (cVEMPs) measurements yet to be determined.

Aims/objectives: To assess how four body positions used during clinical recordings of cVEMPs affect cVEMP parameters.

Material And Method: cVEMPs of 10 healthy subjects (26-50 years old) were recorded in four body positions: sitting/head rotated; supine/head rotated; semi-recumbent/head rotated and elevated; supine/head elevated.

Results: Mean background sternocleidomastoid muscle (SCM) electrical activity was significantly higher in positions C and D than in positions A and B. The latencies of p13 and n23 differed significantly among the four positions. Raw p13-n23 complex amplitude was significantly greater in positions C and D than in A and B. These differences were reduced when amplitudes were corrected by SCM activity. For positions A and B, one and two subjects, respectively, had an abnormal raw asymmetry ratio (AR). After correction, all subjects had normal ARs in all positions.

Conclusions And Significance: Body positions in which the head is elevated produce a quicker and larger cVEMP response compared to positions in which the head is not elevated. The difference in ARs among positions can be ignored as long as the correction is made.
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http://dx.doi.org/10.1080/00016489.2021.1943520DOI Listing
August 2021

Targeting potential of alginate-glycyl-prednisolone conjugate nanogel to inflamed joints in rats with adjuvant-induced arthritis.

J Drug Target 2021 09 10;29(8):892-899. Epub 2021 Mar 10.

Department of Drug Delivery Research, Hoshi University, Tokyo, Japan.

The efficacy of alginate-glycyl-prednisolone conjugate nanogel (AL-GP-NG) was previously reported to be better than that of prednisolone (PD) alone in arthritic rats. In the present study, novel AL-GP-NG was prepared and its targeting potential was investigated. AL-GP-NG with a PD content of 6.3% (w/w) was obtained and had a slightly larger submicron size and similar zeta potential to that of the previous nanogel. Drug release profiles and pharmacokinetic features were similar to those of the previous nanogel. AL-GP-NG showed prolonged release at weakly acidic and neutral pH and the good systemic retention of total (free + conjugated) PD after an intravenous (i.v.) injection in rats. In animal studies using normal and adjuvant-induced arthritic rats, the distribution of total PD was examined after an i.v. injection. AL-GP-NG achieved a markedly higher drug concentration at inflamed joints than PD alone. Furthermore, ALGP-NG showed specific drug localisation to inflamed joints in arthritic rats, but not in normal rats. Furthermore, specific drug localisation to the joints by AL-GP-NG persisted. Collectively, these results demonstrated the good targeting potential of AL-GP-NG to inflamed joints, suggesting its suitability for the treatment of arthritis.
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http://dx.doi.org/10.1080/1061186X.2021.1892116DOI Listing
September 2021

Preparation and evaluation of conjugate nanogels of glycyl-prednisolone with natural anionic polysaccharides as anti-arthritic delivery systems.

Drug Deliv 2021 Dec;28(1):144-152

Department of Drug Delivery Research, Hoshi University, Tokyo, Japan.

Although prednisolone (PD) is used as an anti-arthritis drug due to its rapid and strong anti-inflammatory potential, its frequent and large dosing often brings about adverse effects. Therefore, targeting therapy has attracted increasing attention to overcome such adverse effects. In the present study, nanogels (NGs) composed of macromolecule-PD conjugates were developed as a novel targeting delivery system, and their anti-inflammatory potential was examined. Conjugates were prepared by carbodiimide coupling between glycyl-prednisolone (GP) and the natural anionic polysaccharides, alginic acid (AL) and hyaluronic acid (HA). NGs were produced by the evaporation of organic solvent from the conjugate solution. The obtained NGs, named AL-GP-NG and HA-GP-NG, respectively, were examined for particle characteristics, release, pharmacokinetics, and efficacy. Both NGs were several hundred nanometers in size, had negative zeta potentials, and several % (w/w) drug contents. They released PD gradually at pH 7.4 and 6. They exhibited fairly good retention in the systemic circulation. In the efficacy examination using rats with adjuvant-induced arthritis, both NGs showed the stronger and more prolonged suppression of paw inflammation than PD alone. These suggested that the present NGs should be possibly useful as anti-arthritis targeting therapeutic systems.
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http://dx.doi.org/10.1080/10717544.2020.1865478DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7782909PMC
December 2021

Large Deformation of a DNA-Origami Nanoarm Induced by the Cumulative Actuation of Tension-Adjustable Modules.

Angew Chem Int Ed Engl 2020 04 20;59(15):6230-6234. Epub 2020 Feb 20.

Department of Robotics, Graduate School of Engineering, Tohoku University, 6-6-01 Aramaki-Aza Aoba, Aoba-ku, Sendai, 980-8579, Japan.

Making use of the programmability and structural flexibility of the DNA molecule, a DNA-origami nanoarm capable of undergoing large deformation is constructed. This DNA-origami nanoarm comprised serially repeated tension-adjustable modules, the cumulative actuation of which resulted in a large deformation of the arm structure, which transformed from a linear shape into an arched shape. Combining atomic force microscopy and theoretical analyses based on the mechanics of materials, we demonstrate that the degree of deformation can be systematically controlled by merely replacing a set of strands that is required for the actuation of the module. Moreover, by employing a G-quadruplex-forming sequence for the actuation, we could achieve reversible ion-induced contraction and relaxation of the nanoarm. The adjustability and scalability of this design could enable the production of DNA nanodevices that exhibit large deformation in response to external stimuli.
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http://dx.doi.org/10.1002/anie.201916233DOI Listing
April 2020

In vitro evaluation of genotoxic effects under magnetic resonant coupling wireless power transfer.

Int J Environ Res Public Health 2015 Apr 7;12(4):3853-63. Epub 2015 Apr 7.

Laboratory of Applied Radio Engineering for Humanosphere, Research Institute for Sustainable Humanosphere, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan.

Wireless power transfer (WPT) technology using the resonant coupling phenomenon has been widely studied, but there are very few studies concerning the possible relationship between WPT exposure and human health. In this study, we investigated whether exposure to magnetic resonant coupling WPT has genotoxic effects on WI38VA13 subcloned 2RA human fibroblast cells. WPT exposure was performed using a helical coil-based exposure system designed to transfer power with 85.4% efficiency at a 12.5-MHz resonant frequency. The magnetic field at the positions of the cell culture dishes is approximately twice the reference level for occupational exposure as stated in the International Commission on Non-Ionizing Radiation Protection (ICNIRP) guidelines. The specific absorption rate at the positions of the cell culture dishes matches the respective reference levels stated in the ICNIRP guidelines. For assessment of genotoxicity, we studied cell growth, cell cycle distribution, DNA strand breaks using the comet assay, micronucleus formation, and hypoxanthine-guanine phosphoribosyltransferase (HPRT) gene mutation, and did not detect any significant effects between the WPT-exposed cells and control cells. Our results suggest that WPT exposure under the conditions of the ICNIRP guidelines does not cause detectable cellular genotoxicity.
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http://dx.doi.org/10.3390/ijerph120403853DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4410220PMC
April 2015

ELF magnetic fields do not affect cell survival and DNA damage induced by ultraviolet B.

Bioelectromagnetics 2014 Feb 12;35(2):108-15. Epub 2013 Oct 12.

Research Institute for Sustainable Humanosphere, Kyoto University, Uji, Japan; Power Engineering R&D Center, Kansai Electric Power Company, Osaka, Japan.

We investigated whether extremely low frequency (ELF) magnetic field exposure has modification effects on cell survival after ultraviolet B (UV-B) irradiation and on repair process of DNA damage induced by UV-B irradiation in WI38VA13 subcloned 2RA and XP2OS(SV) cells. The ELF magnetic field exposure was conducted using a Helmholtz coil-based system that was designed to generate a sinusoidal magnetic field at 5 mT and 60 Hz. Cell survival was assessed by WST assay after UV-B irradiation at 20-80 J/m(2) , ELF magnetic field exposure for 24 h, followed by incubation for 48 h. DNA damage was assessed by quantification of cyclobutane pyrimidine dimer formation and 6-4 photoproduct formation using ELISA after UV-B irradiation at 20-80 J/m(2) followed by ELF magnetic field exposure for 24 h. No significant changes were observed in cell survival between ELF magnetic field and sham exposures. Similarly, DNA damage induced by UV-B irradiation did not change significantly following ELF magnetic field exposure. Our results suggest that ELF magnetic field exposure at 5 mT does not have modification effect on cell survival after UV-B irradiation and on repair process of DNA damage induced by UV-B irradiation.
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http://dx.doi.org/10.1002/bem.21821DOI Listing
February 2014

Biopersistence of inhaled MWCNT in rat lungs in a 4-week well-characterized exposure.

Inhal Toxicol 2011 Nov;23(13):784-91

Institute of Industrial Ecological Sciences, University of Occupational and Environmental Health, Japan, Kitakyushu, Japan.

It is important to conduct a risk assessment that includes hazard assessment and exposure assessment for the safe production and handling of newly developed nanomaterials. We conducted an inhalation study of a multi-wall carbon nanotube (MWCNT) as a hazard assessment. Male Wistar rats were exposed to well-dispersed MWCNT for 4 weeks by whole body inhalation. The exposure concentration in the chamber was 0.37 ± 0.18 mg/m³. About 70% of the MWCNTs in the chamber were single fiber. The geometric mean diameter (geometric standard deviation, GSD) and geometric mean length (GSD) of the aerosolized MWCNTs in the chamber were 63 nm (1.5) and 1.1 μm (2.7), respectively. The amounts of MWCNT deposited in the rat lungs were determined by the X-ray diffraction method and elemental carbon analysis. The average deposited amounts at 3 days after the inhalation were 68 μg/lung by the X-ray diffraction method and 76 μg/lung by elemental carbon analysis. The calculated deposition fractions were 18% and 20% in each analysis. The amount of retained MWCNT in the lungs until 3 months after the inhalation decreased exponentially and the calculated biological half times of MWCNT were 51 days and 54 days, respectively. The clearance was not delayed, but a slight increase in lung weight at 3 days after the inhalation was observed.
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http://dx.doi.org/10.3109/08958378.2011.608096DOI Listing
November 2011

Pulmonary and systemic responses of highly pure and well-dispersed single-wall carbon nanotubes after intratracheal instillation in rats.

Inhal Toxicol 2011 Nov 17;23(13):814-28. Epub 2011 Oct 17.

Research Institute of Science for Safety and Sustainability, National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan.

The present study was conducted to assess the pulmonary and systemic responses in rats after intratracheal instillation of highly pure, well-dispersed, and well-characterized SWCNTs. Exposure to SWCNTs up to 2 mg/kg did not produce mortality, changes in clinical signs, or body weights during the observation period. Dose-dependent changes were observed in the lung weight, BALF inflammatory cells, and biochemical parameters such as LDH value, protein content, IL-1β and IL-6 activity, and histopathology. In the 0.04 mg/kg SWCNT-exposed group, almost no changes were observed during the observation period. In the 0.2 mg/kg SWCNT-exposed group, pulmonary inflammatory responses were observed after instillation. In the 1 mg/kg and 2 mg/kg SWCNT-exposed group, acute lung inflammation and subsequent granuloma accompanied by increased lung weights were observed. Furthermore, the histopathological findings in the lungs of rats exposed to SWCNTs showed inflammatory responses related with the vital reaction to the foreign substance that was instilled intratracheally, and there were no fibrosis, atypical lesion, or tumor-related findings even at the highest dose (2 mg/kg) of SWCNT-exposed groups up to 6 months after instillation. For all groups, histopathological changes due to the instillation exposure of SWCNTs were observed only in the lungs and lung-associated lymph nodes and not in the other tissues examined (i.e. the liver, kidney, spleen, and cerebrum).
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http://dx.doi.org/10.3109/08958378.2011.614968DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3251003PMC
November 2011

Pulmonary toxicity of well-dispersed single-wall carbon nanotubes after inhalation.

Nanotoxicology 2012 Nov 26;6(7):766-75. Epub 2011 Sep 26.

Institute of Industrial Ecological Sciences, University of Occupational and Environmental Health Japan, Kitakyushu, Japan.

Single-wall carbon nanotubes (SWCNTs) were well-dispersed by ultrasonication to conduct an inhalation study. SWCNTs were generated using a pressurised nebuliser with liquid suspension of SWCNTs. Wistar rats were exposed to the well-dispersed SWCNT (diameter of bundle: 0.2 μm; length of bundle: 0.7 μm) for 4 weeks. The low and high mass concentrations of SWCNTs were 0.03 ± 0.003 and 0.13 ± 0.03 mg/m(3), respectively. The rats were sacrificed at 3 days, 1 month, and 3 months after the end of exposure. There were no increases of total cell or neutrophil counts in the bronchoalveolar lavage fluid (BALF), or the concentration of cytokine-induced neutrophil chemoattractant in the lungs or BALF in both the high and low concentration-exposed groups. Pulmonary infiltration of neutrophils was not observed in either exposed group throughout the observation period. Well-dispersed SWCNT did not induce neutrophil inflammation in the lung under the conditions in the present study.
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http://dx.doi.org/10.3109/17435390.2011.620719DOI Listing
November 2012

Evaluation of the genotoxic potential of single-wall carbon nanotubes by using a battery of in vitro and in vivo genotoxicity assays.

Regul Toxicol Pharmacol 2011 Nov 29;61(2):192-8. Epub 2011 Jul 29.

Research Institute of Science for Safety and Sustainability, National Institute of Advanced Industrial Science and Technology (AIST), Ibaraki, Japan.

The genotoxic potential of a high purity sample of single-wall carbon nanotubes (SWCNTs) was evaluated using a battery of in vitro and in vivo genotoxicity assays. These comprised a bacterial reverse mutation test (Ames test), an in vitro chromosomal aberration test, and an in vivo mouse bone marrow micronucleus test. The SWCNTs exerted no genotoxicity in Salmonella typhimurium TA97, TA98, TA100, and TA1535, or in Escherichia coli WP2 uvrA/pKM101, whether in the absence or presence of metabolic activation and at concentrations of 12.5-500 μg/plate. In the chromosomal aberration test, at 300-1000 μg/mL, the SWCNTs did not increase the number of structural or numerical chromosomal aberrations, whether the test was conducted with or without metabolic activation. In the in vivo bone marrow micronucleus test, doses of 60 mg/kg and 200mg/kg SWCNTs did not affect the proportions of immature and total erythrocytes, nor did it increase the number of micronuclei in the immature erythrocytes of mice. The results of these studies show that the high purity and well-dispersed sample of SWCNTs are not genotoxic under the conditions of the in vitro bacterial reverse mutation assay, chromosomal aberration assay, or in vivo bone marrow micronucleus test, and thus appear not to pose a genotoxic risk to human health in vivo.
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http://dx.doi.org/10.1016/j.yrtph.2011.07.008DOI Listing
November 2011

Pulmonary toxicity of well-dispersed multi-wall carbon nanotubes following inhalation and intratracheal instillation.

Nanotoxicology 2012 Sep 29;6(6):587-99. Epub 2011 Jun 29.

Institute of Industrial Ecological Sciences, School of Medicine, University of Occupational and Environment Health, Japan.

Multi-walled carbon nanotubes (MWCNTs), dispersed in suspensions consisting mainly of individual tubes, were used for intratracheal instillation and inhalation studies. Rats intratracheally received a dose of 0.2 mg, or 1 mg of MWCNTs and were sacrificed from 3 days to 6 months. MWCNTs induced a pulmonary inflammation, as evidenced by a transient neutrophil response in the low-dose groups, and presence of small granulomatous lesion and persistent neutrophil infiltration in the high-dose groups. In the inhalation study, rats were exposed to 0.37 mg/m(3) aerosols of well-dispersed MWCNTs (>70% of MWCNTs were individual fibers) for 4 weeks, and were sacrificed at 3 days, 1 month, and 3 months after the end of exposure. The inhalation exposures delivered less amounts of MWCNTs into the lungs, and therefore less pulmonary inflammation responses was observed, as compared to intratracheal instillation. The results of our study show that well-dispersed MWCNT can produce pulmonary lesions, including inflammation.
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http://dx.doi.org/10.3109/17435390.2011.594912DOI Listing
September 2012

Biological response and morphological assessment of individually dispersed multi-wall carbon nanotubes in the lung after intratracheal instillation in rats.

Toxicology 2010 Oct 7;276(3):143-53. Epub 2010 Aug 7.

Research Institute of Science for Safety and Sustainability, National Institute of Advanced Industrial Science and Technology, 16-1 Onagawa, Tsukuba, Ibaraki 305-8569, Japan.

Biological responses of multi-wall carbon nanotubes (MWCNTs) were assessed after a single intratracheal instillation in rats. The diameter and median length of the MWCNTs used in this study were approximately 60 nm and 1.5 μm, respectively. Groups of male Sprague-Dawley rats were intratracheally instilled with 0.04, 0.2, or 1 mg/kg of the individually dispersed MWCNT suspension. After instillation, the bronchoalveolar lavage fluid was assessed for inflammatory cells and markers, and the lung, liver, kidney, spleen, and cerebrum were histopathologically evaluated at 3-day, 1-week, 1-month, 3-month, and 6-month post-exposure. Transient pulmonary inflammatory responses were observed only in the lungs of the group of rats exposed to 1 mg/kg of MWCNTs. Morphology of the instilled MWCNTs in the lungs of rats was assessed using light microscopy and transmission electron microscopy (TEM). Light microscopy examination revealed that MWCNTs deposited in the lungs of the rats were typically phagocytosed by the alveolar macrophages and these macrophages were consequently accumulated in the alveoli until 6-month post-exposure. The 400 TEM images obtained showed that all MWCNTs were located in the alveolar macrophages or macrophages in the interstitial tissues, and MWCNTs were not located in the cells of the interstitial tissues. There was no evidence of chronic inflammation, such as angiogenesis or fibrosis, induced by MWCNT instillation. These results suggest that MWCNTs were being processed and cleared by alveolar macrophages.
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http://dx.doi.org/10.1016/j.tox.2010.07.021DOI Listing
October 2010

A black body absorber from vertically aligned single-walled carbon nanotubes.

Proc Natl Acad Sci U S A 2009 Apr 1;106(15):6044-7. Epub 2009 Apr 1.

Research Center for Advanced Carbon Materials, National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki 305-8565, Japan.

Among all known materials, we found that a forest of vertically aligned single-walled carbon nanotubes behaves most similarly to a black body, a theoretical material that absorbs all incident light. A requirement for an object to behave as a black body is to perfectly absorb light of all wavelengths. This important feature has not been observed for real materials because materials intrinsically have specific absorption bands because of their structure and composition. We found a material that can absorb light almost perfectly across a very wide spectral range (0.2-200 mum). We attribute this black body behavior to stem from the sparseness and imperfect alignment of the vertical single-walled carbon nanotubes.
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http://dx.doi.org/10.1073/pnas.0900155106DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2669394PMC
April 2009

Integrated three-dimensional microelectromechanical devices from processable carbon nanotube wafers.

Nat Nanotechnol 2008 May 4;3(5):289-94. Epub 2008 May 4.

Nanotube Research Center, National Institute of Advanced Industrial Science and Technology, Tsukuba 305-8565, Japan.

In order to be useful as microelectromechanical devices, carbon nanotubes with well-controlled properties and orientations should be made at high density and be placed at predefined locations. We address this challenge by hierarchically assembling carbon nanotubes into closely packed and highly aligned three-dimensional wafer films from which a wide range of complex and three-dimensional nanotube structures were lithographically fabricated. These include carbon nanotube islands on substrates, suspended sheets and beams, and three-dimensional cantilevers, all of which exist as single cohesive units with useful mechanical and electrical properties. Every fabrication step is both parallel and scalable, which makes it easy to further integrate these structures into functional three-dimensional nanodevice systems. Our approach opens up new ways to make economical and scalable devices with unprecedented structural complexity and functionality.
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http://dx.doi.org/10.1038/nnano.2008.98DOI Listing
May 2008

Size-selective growth of double-walled carbon nanotube forests from engineered iron catalysts.

Nat Nanotechnol 2006 Nov 3;1(2):131-6. Epub 2006 Nov 3.

Research Center for Advanced Carbon Materials, National Institute of Advanced Industrial Science and Technology, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan.

We have succeeded in synthesizing vertically aligned doubled-walled carbon nanotube (DWNT) forests with heights of up to 2.2 mm by water-assisted chemical vapour deposition (CVD). We achieved 85% selectivity of DWNTs through a semi-empirical analysis of the relationships between the tube type and mean diameter and between the mean diameter and the film thickness of sputtered Fe, which was used here as a catalyst. Accordingly, catalysts were engineered for optimum DWNT selectivity by precisely controlling the Fe film thickness. The high efficiency of water-assisted CVD enabled the synthesis of nearly catalyst-free DWNT forests with a carbon purity of 99.95%, which could be templated into organized structures from lithographically patterned catalyst islands.
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http://dx.doi.org/10.1038/nnano.2006.95DOI Listing
November 2006

Selective matching of catalyst element and carbon source in single-walled carbon nanotube synthesis on silicon substrates.

J Phys Chem B 2005 Feb;109(7):2632-7

Research Center for Advanced Carbon Materials, National Institute of Advanced Industrial Science and Technology, Tsukuba, 305-8565, Japan.

We have studied the compatibility of various catalysts for ethylene and ethanol chemical vapor deposition (CVD) syntheses of single-walled carbon nanotubes (SWNTs) on Si substrates. A strong selectivity between the catalyst elemental species and carbon source was found; SWNT yield for Fe (Co) catalysts was much higher for ethylene (ethanol) CVD than for ethanol (ethylene) CVD. This strong and completely opposite selectivity implies significantly different SWNT growth mechanisms for ethanol and ethylene CVD on Si substrates.
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http://dx.doi.org/10.1021/jp0454117DOI Listing
February 2005

84% catalyst activity of water-assisted growth of single walled carbon nanotube forest characterization by a statistical and macroscopic approach.

J Phys Chem B 2006 Apr;110(15):8035-8

Research Center for Advanced Carbon Materials, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba 305-8565, Japan.

We propose a statistical and macroscopic analysis to estimate the catalyst activity of water-assisted growth (super-growth) of single-walled nanotubes (SWNT) and to characterize SWNT forests. The catalyst activity was estimated to be 84% (+/-6%), the highest ever reported. The SWNT forest was found to be a very sparse material where SWNTs represent only 3.6% of the total volume. This structural sparseness is believed to play a critical role in achieving highly efficient growth.
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http://dx.doi.org/10.1021/jp060080eDOI Listing
April 2006

Kinetics of water-assisted single-walled carbon nanotube synthesis revealed by a time-evolution analysis.

Phys Rev Lett 2005 Jul 29;95(5):056104. Epub 2005 Jul 29.

Japan Fine Ceramics Center, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, 305-8565, Japan.

Here we investigate the kinetics of water-assisted CVD (henceforth denoted as supergrowth CVD) by a quantitative time-evolution analysis based on a simple growth model. We found that the supergrowth can be well described by a model where the dynamics of the catalyst activity is treated similar to radioactive decay. An in-depth analysis based on this growth model revealed the kinetics of the supergrowth CVD, showing a scale relationship between the carbon source and water, and elucidated the role of water as a catalyst activity enhancer and preserver.
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http://dx.doi.org/10.1103/PhysRevLett.95.056104DOI Listing
July 2005

Water-assisted highly efficient synthesis of impurity-free single-walled carbon nanotubes.

Science 2004 Nov;306(5700):1362-4

Research Center for Advanced Carbon Materials, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, 305-8565, Japan.

We demonstrate the efficient chemical vapor deposition synthesis of single-walled carbon nanotubes where the activity and lifetime of the catalysts are enhanced by water. Water-stimulated enhanced catalytic activity results in massive growth of superdense and vertically aligned nanotube forests with heights up to 2.5 millimeters that can be easily separated from the catalysts, providing nanotube material with carbon purity above 99.98%. Moreover, patterned, highly organized intrinsic nanotube structures were successfully fabricated. The water-assisted synthesis method addresses many critical problems that currently plague carbon nanotube synthesis.
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http://dx.doi.org/10.1126/science.1104962DOI Listing
November 2004
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