Long polymeric tips of atomic force microscopy for large biological samples:

MURAMATSU, H.,YAMAMOTO, Y.,SATO, A.,ENOMOTO, S.,KIM, W. S.,CHANG, S. M.,KIM, J. M. Blackwell Publishing Ltd 2006 Journal of microscopy Vol.224 No.2

Pressure-Induced Selectivity for Probing Inner Tubes in Double- and Triple-Walled Carbon Nanotubes: A Resonance Raman Study

Alencar, R. S.,Aguiar, A. L.,Paschoal, A. R.,Freire, P. T. C.,Kim, Y. A.,Muramatsu, H.,Endo, M.,Terrones, H.,Terrones, M.,San-Miguel, A.,Dresselhaus, M. S.,Souza Filho, A. G. American Chemical Society 2014 The Journal of Physical Chemistry Part C Vol.118 No.15

<P>The dependence of the radial breathing modes (RBMs) and the tangential mode (G-band) of triple-wall carbon nanotubes (TWCNTs) under hydrostatic pressure is reported. Pressure screening effects are observed for the innermost tubes of TWCNTs similar to what has been already found for DWCNTs. However, using the RBM pressure coefficients in conjunction with the histogram of the diameter distribution, we were able to separate the RBM Raman contribution related to the intermediate tubes of TWCNTs from that related to the inner tubes of DWCNTs. By combining Raman spectroscopy and high-pressure measurements, it was possible to identify these two categories of inner tubes even if the two tubes exhibit the same diameters because their pressure response is different. Furthermore, it was possible to observe similar RBM profiles for the innermost tubes of TWCNTs using different resonance laser energies but also under different pressure conditions. This is attributed to changes in the electronic transition energies caused by small pressure-induced deformations. By using Raman spectroscopy, it was possible to estimate the displacement of the optical energy levels with pressure.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jpccck/2014/jpccck.2014.118.issue-15/jp4126045/production/images/medium/jp-2013-126045_0004.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/jp4126045'>ACS Electronic Supporting Info</A></P>

Linear carbon chains inside multi-walled carbon nanotubes: Growth mechanism, thermal stability and electrical properties

Kang, C.S.,Fujisawa, K.,Ko, Y.I.,Muramatsu, H.,Hayashi, T.,Endo, M.,Kim, H.J.,Lim, D.,Kim, J.H.,Jung, Y.C.,Terrones, M.,Dresselhaus, M.S.,Kim, Y.A. Pergamon Press ; Elsevier Science Ltd 2016 Carbon Vol.107 No.-

<P>Linear carbon chains (LCCs) consisting of sp-hybridized carbon atoms are considered a fascinating 1D system and could be used in the fabrication of the next-generation molecular devices because of its ideal linear atomic nature. A large portion of long LCCs inside multi-walled carbon nanotubes (MWCNTs) were synthesized by atmospheric arc discharge in the presence of boron. Closed-end growth of MWCNTs in the arc process is suggested as a critical condition for the simultaneous growth of LCCs within the inner cores of carbon nanotubes. The strong Raman line around 1850 cm(-1) was used to characterize the degree of filling as well as their structural stability under high temperature thermal treatments. We observed a distinctive change in the electrical conductivity of the MWCNT assembly before and after the disappearance of LCCs due to the expected strong coupling interaction between the LCCs and the innermost tube. This work demonstrates for the first time the enhanced effect of confined linear carbon chains on the overall electrical conductivity of MWCNT assemblies. (C) 2016 Elsevier Ltd. All rights reserved.</P>

From high pressure radial collapse to graphene ribbon formation in triple-wall carbon nanotubes

Silva-Santos, S.D.,Alencar, R.S.,Aguiar, A.L.,Kim, Y.A.,Muramatsu, H.,Endo, M.,Blanchard, N.P.,San-Miguel, A.,Souza Filho, A.G. Elsevier 2019 Carbon Vol.141 No.-

<P><B>Abstract</B></P> <P>The radial stability and the irreversible transformation of triple-wall carbon nanotubes (TWCNTs) bundles are investigated at high pressure conditions both experimentally and theoretically (exp. up 72 GPa). The tubes having a mean internal diameter of 0.83 nm and graphite-like intertube distance, show an onset of the radial collapse evidenced by the evolution of optical phonons. The nanotube collapse onset is observed at ∼ 22 GPa completes for the two external tubes at ∼ 29 GPa, however the innermost tube remains stable up to ∼ 37 GPa. Molecular dynamic calculations performed on smaller diameter TWCNTs bundles, as a model system, confirmed the multiple-stage pressure-induced collapse process. An analytical expression for the collapse pressure of carbon nanotubes having an arbitrary number of walls is proposed. Our experiments and modelling show that for pressures beyond ∼ 60 GPa an irreversible structural transformation of TWCNTs takes place. <I>Ex situ</I> transmission electron microscopy characterization on the recovered sample from 72 GPa revealed the mechanical failure of carbon nanotubes which evolve towards ribbon-like structures as corroborated by Raman spectroscopy. Modelling the tubes evolution at high pressure and high temperature showed the formation of new structures ranging from ribbon-like to graphite-like with either different degrees of amorphization or s <SUP> p 3 </SUP> interlinking.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Polymer tips for application of atomic force microscopy

Kim, W.S.,Park, K.M.,Park, J.J.,Chang, S.M.,Kim, I.H.,Muramatsu, H.,Kim, J.M. ELSEVIER 2007 CURRENT APPLIED PHYSICS Vol.7 No.5

A hydrophobic polymer tip for atomic force microscopy has been fabricated by two-photon adsorbed photopolymerization techniques and has been applied for the high resolution imaging of a hydrophilic metal surface. Using optimized photopolymerization conditions, we have succeeded in fabricating sub-100-nm sized polymer tips. This fabricating resolution of two-photon adsorbed photopolymerization is also confirmed by other supporting experiments. The imaging results show that the capillary-force-induced image distortion can be successfully removed by applying a pure hydrophobic polymer tip with a lateral resolution better than 5nm, which is difficult to achieve with a commercial tip without any environmental control.

Involvement of laminin and integrins in adhesion and migration of junctional epithelium cells

Kinumatsu, T.,Hashimoto, S.,Muramatsu, T.,Sasaki, H.,Jung, H-S,Yamada, S.,Shimono, M. Blackwell Publishing Ltd 2009 Journal of periodontal research Vol.44 No.1

<P>Background and Objective: </P><P>The junctional epithelium attaches to the enamel surface with hemidesmosomes (of which laminin-5 and integrin-&agr;<SUB>6</SUB>&bgr;<SUB>4</SUB> are the main components) in the internal basal lamina. Laminin-5 is also involved in cell motility with integrin-&agr;<SUB>3</SUB>&bgr;<SUB>1</SUB>, although their functions have not yet been clarified. The purpose of this study was to determine the functions of those adhesive components between the tooth and the junctional epithelium during cell migration. Because an idea has been proposed that directly attached to tooth cells (DAT cells) may not contribute to cell migration, 5-bromo-2-deoxyuridine staining was performed to confirm cell migration.</P><P>Material and Methods: </P><P>We investigated laminin-&ggr;<SUB>2</SUB> (contained only in laminin-5), integrin-&bgr;<SUB>4</SUB> (involved in cell–extracellular matrix contact) and integrin-&agr;<SUB>3</SUB> (inducing cell migration) in the junctional epithelium, oral gingival epithelium and gingival sulcus epithelium of 6-wk-old ICR mice using laser microdissection, quantitative real-time reverse transcription-polymerase chain reaction, immunofluorescence and 5-bromo-2-deoxyuridine staining.</P><P>Results: </P><P>Laminin and integrins were clearly immunolocalized in the basal lamina of all epithelium. Quantitative analysis of laminin and integrin mRNAs by laser microdissection showed that they were more highly expressed in DAT cells than in basal cells in the oral gingival epithelium. In particular, a 12-fold higher expression of laminin-5 was observed in the junctional epithelium compared with the oral gingival epithelium. 5-Bromo-2-deoxyuridine staining showed rapid coronal migration of DAT cells.</P><P>Conclusion: </P><P>These results suggest that the abundant expression of laminin-5 and integrin-&agr;<SUB>6</SUB>&bgr;<SUB>4</SUB> is involved in the attachment of DAT cells to teeth by hemidesmosomes. Abundant expression of laminin-5 and integrin-&agr;<SUB>3</SUB>&bgr;<SUB>1</SUB> might assist in DAT cell migration, confirmed by 5-bromo-2-deoxyuridine staining during the turnover of junctional epithelium.</P>

Immunolocalization of laminin and integrin in regenerating junctional epithelium of mice after gingivectomy

Masaoka, T.,Hashimoto, S.,Kinumatsu, T.,Muramatsu, T.,Jung, H.-S.,Yamada, S.,Shimono, M. Blackwell Publishing Ltd 2009 Journal of periodontal research Vol.44 No.4

<P>Background and Objective: </P><P>The expression patterns of adhesive proteins and extracellular matrix proteins in regenerating gingival epithelium after gingivectomy are unknown. The aim of this study was to examine the expression of laminin 1, laminin &ggr;<SUB>2</SUB> (a specific component of laminin 5), integrin &bgr;<SUB>4</SUB> and integrin &agr;<SUB>3</SUB> in the regenerating gingival epithelium in order to understand the mechanism of wound healing during reconstitution of the sulcular environment.</P><P>Material and Methods: </P><P>The palatal gingivae of the maxillary molars of Institute of Cancer Research mice were excised, and the regenerating tissues were examined 1, 3, 5, 7 and 14 days later. Fresh, non-fixed and non-decalcified frozen sections were prepared and stained using immunofluorescence.</P><P>Results: </P><P>At 1 day post-surgery, intense expression of laminin &ggr;<SUB>2</SUB>, integrin &bgr;<SUB>4</SUB> and integrin &agr;<SUB>3</SUB> was distinct in the frontal margin of the regenerating oral epithelium. Laminin &ggr;<SUB>2</SUB> was diffusely detected on the root surface and in connective tissues beneath the regenerating oral epithelium at 3 and 5 days. At 7 days, laminin &ggr;<SUB>2</SUB> was intermittently recognizable in the internal basal lamina (IBL) close to tooth-facing cells, while laminin &ggr;<SUB>2</SUB>, integrin &bgr;<SUB>4</SUB> and integrin &agr;<SUB>3</SUB> were observed in the IBL and in the external basal lamina (EBL) of the regenerating junctional epithelium at 14 days.</P><P>Conclusion: </P><P>These results suggest that secretion of laminin 5 in the connective tissue may induce epithelial cell migration, and that binding of laminin 5 to integrin &agr;<SUB>6</SUB>&bgr;<SUB>4</SUB> and integrin &agr;<SUB>3</SUB>&bgr;<SUB>1</SUB> in the IBL may provoke cell adhesion and migration of cells facing the tooth on the enamel surface of the regenerating junctional epithelium.</P>

Wide Area Distribution of Nitrogen Concentrations in Mountain Streams of Hyogo Prefecture, Japan

K. Muramatsu,Y. Komai,S. Umemoto,T. Inoue 대한환경공학회 2010 Environmental Engineering Research Vol.15 No.2

To study the relationship between the concentrations of nitrogen in mountain streams, and anthropologic and natural factors, the water chemistry of the mountain streams in the entire Hyogo Prefecture, Japan, were investigated. A thousand mountain streams were investigated between 1998 and 2001. The concentrations of nitrate nitrogen ranged from 2.92 to 0.1 mg/L, with an arithmetic mean value of 0.45 mg/L. A number of streams showing more than 1.0 mg/L of nitrate nitrogen accounted for 8% of the mountain streams investigated. These results indicated that the concentrations of nitrate nitrogen in the mountain streams were low in the entire Hyogo Prefecture. In general, the mountain stream water in Hyogo Prefecture appears to not have been affected by wet and dry deposition originating from anthropologic sources in mountain streams and Japan. On the other hand, sites with more than 0.8 mg/L nitrate nitrogen were distributed over the entire Hyogo Prefecture, which were classified into five groups. Each group showed unique geographical, geological and anthropological characteristics. No common characteristic among five groups were discover. These results suggest that the cause of high concentrations of nitrogen in mountain streams is not from a uniform set of conditions.

Covalent Attachment of Aromatic Diisocyanate to the Sidewalls of Single‐ and Double‐Walled Carbon Nanotubes

Jung, Yong Chae,Muramatsu, Hiroyuki,Hayashi, Takuya,Kim, Jin Hee,Kim, Yoong Ahm,Endo, Morinobu,Dresselhaus, Mildred S. WILEY‐VCH Verlag 2010 European journal of inorganic chemistry Vol.2010 No.27

<P><B>Abstract</B></P><P>We carried out covalent functionalization of single‐ and double‐walled carbon nanotubes (SWNTs and DWNTs) comparatively by using isocyanate chemistry. The introduction of aromatic diisocyanate on the sidewalls of the tubes was verified by the strong IR peak around 2272 cm<SUP>–1</SUP> arising from the NCO asymmetric stretching mode, by the intensified sp<SUP>3</SUP> peak at 285.2 eV in the C1s photoemission spectra, and by a typical TEM image of the amorphous‐like coating. The suppression of the optical properties in a covalently isocyanate‐functionalized SWNT is due to a breakdown of the van Hove singularities, whereas the strong optical activity in a covalently isocyanate‐functionalized DWNT originates from the geometrically shielded inner tubes. The chemically active isocyanate groups at the end of the phenyl diisocyanate that are covalently attached to the sidewalls of the DWNTs will allow us to utilize isocyanate chemistry in synthesizing functional organic–inorganic hybrid materials as well as high‐performance polymer composites.</P>

Estimating 3-D Surface Geometrical Features on the Basis of Surface Curvature Consistency

H.B. Zha,S. Muramatsu,T. Nagata 제어로봇시스템학회 1993 제어로봇시스템학회 국내학술대회 논문집 Vol.1993 No.10