Faculty Profiles - NAKANISHI Kazuki

Papers - NAKANISHI Kazuki

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Preparation of silicalite-1 within macroporous silica glass Reviewed

Shikata H, Nakanishi K, Hirao K

JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY Vol. 19 ( 1-3 ) page： 769 - 773 2000.12

Preparation and chromatographic application of macroporous silicate in a capillary Reviewed

Ishizuka N, Nakanishi K, Hirao K, Tanaka N

JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY Vol. 19 ( 1-3 ) page： 371 - 375 2000.12

Porous gels made by phase separation: Recent progress and future directions Reviewed

Nakanishi K

JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY Vol. 19 ( 1-3 ) page： 65 - 70 2000.12

Membrane emulsification using sol-gel derived macroporous silica glass Reviewed

Fuchigami T, Toki M, Nakanishi K

JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY Vol. 19 ( 1-3 ) page： 337 - 341 2000.12

Performance of a monolithic silica column in a capillary under pressure-driven and electrodriven conditions Reviewed

Ishizuka N, Minakuchi H, Nakanishi K, Soga N, Nagayama H, Hosoya K, Tanaka N

ANALYTICAL CHEMISTRY Vol. 72 ( 6 ) page： 1275 - 1280 2000.3

Formation of hierarchical pore structure in silica gel Reviewed

Nakanishi K, Takahashi R, Nagakane T, Kitayama K, Koheiya N, Shikata H, Soga N

JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY Vol. 17 ( 3 ) page： 191 - 210 2000.3

A new monolithic-type HPLC column for fast separations

Cabrera K, Lubda D, Eggenweiler HM, Minakuchi H, Nakanishi K

HRC-JOURNAL OF HIGH RESOLUTION CHROMATOGRAPHY Vol. 23 ( 1 ) page： 93-99 2000.1

Monolithic silica columns for HPLC, micro-HPLC, and CEC Reviewed

Tanaka N, Nagayama H, Kobayashi H, Ikegami T, Hosoya K, Ishizuka N, Minakuchi H, Nakanishi K, Cabrera K, Lubda D

HRC-JOURNAL OF HIGH RESOLUTION CHROMATOGRAPHY Vol. 23 ( 1 ) page： 111 - 116 2000.1

Tailoring mesopores in monolithic macroporous silica for HPLC Reviewed

Nakanishi K, Shikata H, Ishizuka N, Koheiya N, Soga N

HRC-JOURNAL OF HIGH RESOLUTION CHROMATOGRAPHY Vol. 23 ( 1 ) page： 106 - 110 2000.1

Aggregation behavior of alkoxide-derived silica in sol-gel process in presence of poly(ethylene oxide) Reviewed

R Takahashi, K Nakanishi, N Soga

JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY Vol. 17 ( 1 ) page： 7 - 18 2000.1

Language：English Publishing type：Research paper (scientific journal) Publisher：KLUWER ACADEMIC PUBL

Growth behavior of silica in an acid catalyzed sol-gel process from silicon alkoxide in the presence of poly(ethylene oxide), PEO, was investigated by in situ small angle X-ray scattering, SAXS, and Si-29 NMR measurements. The results of SAXS, that aggregation and gel formation behaviors of silica were affected by the presence of PEO, suggested a strong attractive interaction between silica oligomers and PEO. A possible reaction scheme of silica in the presence of PEO is as follows; (1) PEO and small silica oligomers coexist in the solution without specific interaction just after hydrolysis of the silicon alkoxide. (2) With the progress of condensation, a ramified aggregated complex between PEO and silica oligomers is formed, which is characterized by larger apparent value of radius of gyration and smaller fractal dimension than in the PEO-free system. (3) After gelation, the fractal dimension of scatterers remains to be smaller than that in the PEO-free system, because PEO associated with the silica network inhibits aggregation within the gel networks. Furthermore, PEO inhibits the condensation in the aging and in the drying process, leading to less strongly crosslinked dry gel. A temporal maximum in the time evolution of R-g was observed for the samples separated into two phases with their characteristic domain size being larger than several micrometers. This is considered to be a phenomenon related to increase and divergence of correlation length near and at the critical point.

DOI： 10.1023/A:1008753718586

Effect of nonionic surfactant on phase separation behavior in methylsiloxane sol-gel systems Reviewed

Nakanishi K, Miyawaki S, Soga N

KOBUNSHI RONBUNSHU Vol. 57 ( 6 ) page： 396 - 401 2000

Apatite formation on ethylene-vinyl alcohol copolymer modified with silane coupling agent and calcium silicate Reviewed

A Oyane, M Minoda, T Miyamoto, K Nakanishi, M Kawashita, T Kokubo, T Nakamura

BIOCERAMICS Vol. 192-1 page： 713 - 716 2000

Language：English Publishing type：Research paper (scientific journal) Publisher：TRANS TECH PUBLICATIONS LTD

Silanol (SI-OH) groups on materials are believed to induce the apatite nucleation in the body environment. In the present study, the apatite-forming ability of ethylene-vinyl alcohol copolymer (EVOH), whose surface was modified to be abundant in Si-OH groups, was investigated in a simulated body fluid (SBF) with ion concentrations nearly equal to those of human blood plasma. Surface modification of EVOH with Si-OH groups was carried out by reacting isocyanatopropyltriethoxy silane (IPTS) and subsequent hydrolysis of its Si-OC2H5 groups by 1 M-HCl or saturated Ca(OH)(2) aqueous solution. Apatite was, however, not formed on thus surface-modified EVOH in SBF even after 7 d. When the IPTS-treated EVOH was treated with silica or calcium silicate solution, the obtained specimen formed the apatite on its surface in SBF within 7 or 2 d, respectively. The present surface-modification of EVOH is effective for obtaining an apatite-polymer fiber composite in SBF, which could give bone substitute having bone-bonding ability as well as mechanical properties analogous to those of the natural bone.

DOI： 10.4028/www.scientific.net/KEM.192-195.713

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A new monolithic-type HPLC column for fast separations

Karin Cabrera, Dieter Lubda, Hans Michael Eggenweiler, H. Minakuchi, K. Nakanishi

Journal of Separation Science Vol. 23 ( 1 ) page： 93 - 99 2000

Language：English Publishing type：Research paper (scientific journal)

The application of a new silica-based, monolithic-type HPLC-column for fast separations is presented. The column is prepared according to a new sol-gel process, which is based on the hydrolysis and polycondensation of alkoxysilanes in the presence of water soluble polymers. The method leads to "rods" made of a single piece of porous silica with a defined pore structure, i. e. macro- and mesopores. The main feature of silica rod columns is a higher total porosity, about 15% higher than of conventional particulate HPLC columns. The resulting column pressure drop is therefore much lower, allowing operation at higher flow rates including flow gradients. Consequently, HPLC analysis can be performed much faster, as it is demonstrated by various applications. © WILEY-VCH Verlag GmbH, D-69451 Weinheim 2000.

DOI： 10.1002/(SICI)1521-4168(20000101)23:1<93::AID-JHRC93>3.0.CO;2-2

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A new monolithic-type HPLC column for fast separations Reviewed

Cabrera K., Lubda D., Eggenweiler H.M., Minakuchi H., Nakanishi K.

Journal of Separation Science Vol. 23 ( 1 ) page： 93 - 99 2000

Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Separation Science

DOI： 10.1002/(sici)1521-4168(20000101)23:1<93::aid-jhrc93>3.3.co;2-u

Scopus

Apatite formation on ethylene-vinyl alcohol copolymer modified with silanol groups Reviewed

A Oyane, M Minoda, T Miyamoto, R Takahashi, K Nakanishi, HM Kim, T Kokubo, T Nakamura

JOURNAL OF BIOMEDICAL MATERIALS RESEARCH Vol. 47 ( 3 ) page： 367 - 373 1999.12

Language：English Publishing type：Research paper (scientific journal) Publisher：JOHN WILEY & SONS INC

The surfaces of ethylene-vinyl alcohol copolymer (EVOH) substrates were modified with silanol (Si-OH) groups, and their apatite forming ability was examined in a simulated body fluid (SBF) with ion concentrations nearly equal to those of human blood plasma or in a solution with ion concentrations 1.5 times those of SBF (1.5SBF). The surface modification of EVOH was carried out by reacting 3-iso-cyanatopropyltriethoxysilane, followed by hydrolysis of the ethoxysilyl groups into Si-OH groups. However, no apatite formation was observed on the EVOH substrate thus modified, even after 3 weeks in SBF and 1.5SBF. The Si-OH modified EVOH substrate was further modified by hydrolysis and polycondensation of tetraethyoxysilane (TEOS). It was found that the apatite forms on the TEOS-modified substrate within 3 weeks in 1.5SBF. These results suggest that the presence of a large amount of Si-OH groups (i.e., a cluster of Si-OH groups) on the substrate is prerequisite to apatite formation in the body environment. Apatite-EVOH composites prepared by this process might be useful as hard tissues substitutes. (C) 1999 John Wiley & Sons, Inc.

DOI： 10.1002/(SICI)1097-4636(19991205)47:3<367::AID-JBM11>3.0.CO;2-A

Sol-gel modification of silicone to induce apatite-forming ability Reviewed

Oyane A, Nakanishi K, Kim HM, Miyaji F, Kokubo T, Soga N, Nakamura T

BIOMATERIALS Vol. 20 ( 1 ) page： 79 - 84 1999.1

Performance of an octadecylsilylated continuous porous silica column in polypeptide separations Reviewed

Minakuchi H, Ishizuka N, Nakanishi K, Soga N, Tanaka N

JOURNAL OF CHROMATOGRAPHY A Vol. 828 ( 1-2 ) page： 83 - 90 1998.12

Structural study of mesoporous titania and titanium stearic acid complex prepared from titanium alkoxide Reviewed

Takahashi R, Takenaka S, Sato S, Sodesawa T, Ogura K, Nakanishi K

JOURNAL OF THE CHEMICAL SOCIETY-FARADAY TRANSACTIONS Vol. 94 ( 20 ) page： 3161 - 3168 1998.10

Preparation of macroporous titania films by a sol-gel dip-coating method from the system containing poly(ethylene glycol) Reviewed

Kajihara K, Nakanishi K, Tanaka K, Hirao K, Soga N

JOURNAL OF THE AMERICAN CERAMIC SOCIETY Vol. 81 ( 10 ) page： 2670 - 2676 1998.10

Chromatographic properties of miniaturized silica rod columns Reviewed

N Ishizuka, H Minakuchi, K Nakanishi, N Soga, K Hosoya, N Tanaka

HRC-JOURNAL OF HIGH RESOLUTION CHROMATOGRAPHY Vol. 21 ( 8 ) page： 477 - 479 1998.8

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Papers - NAKANISHI Kazuki