M. Hirano, N. Ohtsu, Argon plasma etching process enhancing antibacterial
activity of stainless steel surface via nanopillar fabrication, 7th Asia
COnference on Material and Manufacturing Technology, ACMMT 2025 (11/4-7,
Pattaya, Thailand)
N. Ohtsu, R. Kawakami, M. Hirano, Pulsed anodization technology for improving
the surface biocompatibility of a superelastic NiTi alloy, 7th Asia COnference
on Material and Manufacturing Technology, ACMMT 2025 (11/4-7, Pattaya,
Thailand)
K. Kitazawa, N. Ohtsu, M. Hirano, Investigation of stainless steel nanopillar
surface structure to prevent antibacterial activity deterioration induced
by abrasion, Asian-European International Conference on Plasma Surface
Engineering, AEPSE 2025 (11/2-6, Phuket, Thailand)
Y. Kitadate,A. Yoshino, K. Yonemoto, E. Hashiba, M. Hirano, N. Ohtsu, Wavelength
dependence in laser induced plasma used for fabricating a nitride titanium
surface in air, Asian-European International Conference on Plasma Surface
Engineering, AEPSE 2025 (11/2-6, Phuket, Thailand)
R. Takada, A. Kitayama, M. Hirano, N. Ohts, Effect of the pulsed anodizing
duration on the layer characteristics of NiTi alloy, Asian-European International
Conference on Plasma Surface Engineering, AEPSE 2025 (11/2-6, Phuket, Thailand)
N. Ohtsu, Y. Kitadate, M. Tachibana, M. Hirano, A metal surface nitriding
processable in air utilizing a laser induced plasma, Asian-European International
Conference on Plasma Surface Engineering, AEPSE 2025 (11/2-6, Phuket, Thailand)
M. Hirano, N. Ohtsu, Antibacterial nanopillar formation on stainless steel
surface utilizing argon plasma etching process, Asian-European International
Conference on Plasma Surface Engineering, AEPSE 2025 (11/2-6, Phuket, Thailand)
(Invited) N. Ohtsu, R. Kawakami, M. Hirano, Pulsed anodization process to form a
biocompatible layer on superelastic NiTi alloy surface, International Conference
on Processing & Manufacturing of Advanced Materials, THERMEC'2025 (6/30-7/4,
Tours, France)
(Invited) M. Hirano, K. Miura, N. Ohtsu, R. Kawakami, M. Hirano, Argon plasma etching
process to fabricate the antibacterial nanopillars on stainless steel surface,
International Conference on Processing & Manufacturing of Advanced
Materials, THERMEC'2025 (6/30-7/4, Tours, France)
(Invited) N. Ohtsu, Wear Resistance Improvement of Stainless Steels by An Open Atmosphere
Laser Nitriding, 13th Asia Conference on Mechanical and Materials Engineering,
ACMME' 2025 (6/18-21, Tokyo, Japan)
(Invited) N. Ohtsu, Pulsed anodization to form a biocompatible oxide layer on a
superelastic NiTi alloy, 4th International Symposium on Anodizing Science
and Technology, AST 2025 (6/1-6/4, Narita, Japan)
A. Kitayama, R. Takada, R. Kawakami, M. Hirano, N Ohtsu, Pulsed anodization
to form a biocompatible oxide layer on a superelastic NiTi alloy, 4th International
Symposium on Anodizing Science and Technology, AST 2025 (6/1-6/4, Narita,
Japan)
N. Ohtsu, K. Yonemoto, A. Yoshino, Y. Kitadate, M. Nakai, M. Hirano, Wear
resistance improvement of steinles sttel by a facile laser surface processing,
The14th TSME International Conference on Mechanical Engineering, TSME-ICOME
2024 (12/10-13,Pattaya, Thailand)
(Invited)N. Ohtsu, An open atmosphere laser nitriding on metal surfaces utilizing
a laser induced plasma, 6th Asia Conference on Material and Manufacturing
Technology, ACMMT 2024 (11/25-28, Online)
M. Hirano, K. Maruyama, N. Ohtsu, Enhancing hardness of commercial pure
Ti via radio-frequency magnetron He plasma, The 12th Vacuum and Surface
Science Confernce of Asia and Australia, VASSCAA-12 (10/13-17, Taipei,
Taiwan)
N. Ohtsu, A. Yoshino, K. Yonemoto, An open atmosphere nitriding phenomenon
on metal surfaces triggered by laser induced plasma, 19th Conference on
Plasma Surface Engineering, PSE 2024 (9/2-5, Erfurt, Germany)
K. Yonemoto, A. Yoshino, Y. Kitadate, N. Ohtsu, Characteristic variation
of the focused pulsed laser-irradiated titanium surface in N2-O2 atmosphere
with different mixture ratio, 19th Conference on Plasma Surface Engineering,
PSE 2024 (9/2-5, Erfurt, Germany)
A. Yoshino, K. Yonemoto, Y. Kitadate, T. Kiba, N. Ohtsu, Optimization of
laser-induced plasma for facilitating the open atmosphere laser nitriding
on titanium surface, 19th Conference on Plasma Surface Engineering, PSE
2024 (9/2-5, Erfurt, Germany)
N. Ohtsu, R. Takada R. Kawakami, Dominant characteristic of an anodized
NiTi alloy surface that suppress a Ni ion release in biological environment,
European Conference on Application of Surface and Interface Analysis, ECASIA
2024 (6/9-14,Gothenburg,Sweden)
N. Ohtsu, A. Tsuruta, R. Kawakami, M. Hirano, Fabrication of high durability
photocatalytic N-doped TiO2 layer on Ti substrate through anodization in
hot non-aqueous nitrate electrolyteals, The International Conference on
Applied Physics and Materials Applications, ICAPMA2023 (12/6-9, Pattaya,
Thailand)
(Invited) N. Ohtsu, H. Taniho, K. Tate, Z. Wang, M. Ohta, Pulsed anodization to
improve the biocompatibility of superelastic NiTi alloy, The 11th Pacific
Rim International Conference on Advanced Materials and Processing, PRICM
11 (11/19-23, Jeju, Korea)
Y. Matsui, R. Kawakami, Y. Sakurai, N. Ohtsu, Endothelial cell behavior
on pulsed-anodized NiTi alloys using different electrolytes , The 11th
Pacific Rim International Conference on Advanced Materials and Processing,
PRICM 11 (11/19-23, Jeju, Korea)
R. Kawakami, Y. Matsui, R. Takada, N. Ohtsu, Variation of Ni ion release
behavior of a pulsed-anodized NiTi alloy surface by a voltage setting ,
The 11th Pacific Rim International Conference on Advanced Materials and
Processing, PRICM 11 (11/19-23, Jeju, Korea)
N. Ohtsu, An open atmosphere nitriding phenomenon on metal surfaces triggered
by laser induced plasma, Euromat'2023 (9/3-7, Frankfurt, Germany)
R. Kawakami, K.Tate, Y. Matsui, A. Tsuruta, N. Ohtsu, Variation of Ni-ion
release behaviour of the pulsed anodized NiTi alloy by the adjustment of
pulse waveform, International Conference on Processing & Manufacturing
of Advanced Materials, Thermec'2023 (7/2-7, Vienna, Austria)
(Invited) N. Ohtsu, R. Endo, S. Takeda An open atmosphere nitriding phenomenon on
metal surfaces triggered by laser induced plasma , International Conference
on Processing & Manufacturing of Advanced Materials, Thermec'2023 (7/2-7,
Vienna, Austria)
Y. Sakuraba, N. Ohtsu, R. Kawakami, Hardness distribution generation in
a welded AISI H13 steel and its removal by laser heat treatment, International
Conference on Processing & Manufacturing of Advanced Materials, Thermec'2023
(7/2-7, Vienna, Austria)
(Invited)N. Ohtsu, An open atmosphere laser nitridng process on titanium, 2nd International
Materials Engineering and Advanced Manufacturing Technologies Congress,
IMEAMTC'23, (1/12〜13, Online)
N. Ohtsu, Fractional Analysis Process of Surface-Adsorbed Proteins Using
Sds-Page, Pacific Rim Symposium on Surface, Coatings & Interface, PacSurf
2022 (12/11〜15, Hawaii)
K. Tate、Y. Matsui, R. Kawakami, N. Ohtsu, Cell responses on pulsed-anodized
nitinol alloy with different surface property, 6th International Conference
on Nanomaterials and Biomaterials,ICNB 2022 (11/12〜14, Bangkok)
S. Takeda, M. Hiranoi, N. Ohtsu, Fabrication of antibacterial nanopillars
on AISI 316 surface via argon plasma etchingprocess, 4th Asia Conference
on Material and Manufacturing Technology, ACMMT 2022 (11/12〜14, Bangkok)
R. Endo, S. Takeda, N. Ohtsu, A nitride layer formation on titanium surface
through laser irradiation in an open atmospheric condition, 4th Asia Conference
on Material and Manufacturing Technology, ACMMT 2022 (11/12〜14, Bangkok)
M. Hirano, S. Taleda, N. Ohtsu, Effect of crystal phase and composition
of stainless steels on antibacterial nanopillar surface fabricated by argon
plasma etching, 22th International Vacuum Congress, IVC-22 (9/11〜16, Sapporo)
H. Taniho, K. Tate、R. Kawakami, N. Ohtsu, Characteristic variation of pulsed
anodized NiTi surface caused by the voltage-OFF period, Materials Research
Meetin 2021, MRM2021(12/13〜16, Yokohama)
K.Tate, H. Taniho, R. Kawakami, N. Ohtsu, Cell responses on a pulsed anodized
NiTi surface with a different Ni releasing behavior, Materials Research
Meetin 2021, MRM2021(12/13〜16, Yokohama)
Y. Yotsuji, Y. Funane, N. Ohtsu, Investigation of photocatalytic antiviral
performance on an anodized titanium surface using a temperature-controlled
alcoholic nitrate electrolyte, Materials Research Meetin 2021, MRM2021(12/13〜16,
Yokohama)
(Invited) N. Ohtsu, H. Taniho, K. Tate, Z. Wang, M. Ohta Biological responses on
a surface modified nitinol alloy through the anodization technique, 18th
International Conference on Flow Dynamics, ICFD2021,(10/27-29, Virtual)
K. Yamasaki, H. Taniho, K. Tate, N, Ohtsu, Ni ion release from a pulsed
anodized NiTi alloy surface using various electrolytes, 14th Inbternarional
COnference on Surfaces, Coatings and Nanostructured Materials, NANOSMAT
2020 (9/8〜10, Virtual)
M.Hirano, S. Takeda, K. Miura, M. Yamane, N. Ohtsu, Fabrication of antibacterial
nanopillars on stainless steel surface , 14th Inbternarional COnference
on Surfaces, Coatings and Nanostructured Materials, NANOSMAT 2020 (9/8〜10,
Virtual)
H. Taniho, K. Yamasaki, N. Ohtsu, Enhancement of Ni release inhibition
effect on pulsed anodized NiTi alloy through the pulse width optimization,
14th Inbternarional COnference on Surfaces, Coatings and Nanostructured
Materials, NANOSMAT 2020 (9/8〜10,Virtual)
Y.Funane, S. Yotsuji, N. Ohtsu, Improvement of performances on anodic TiO2
layer using nitrate/non-aqueous electrolyte via temperatures optimization,
14th Inbternarional COnference on Surfaces, Coatings and Nanostructured
Materials, NANOSMAT 2020 (9/8〜10,Virtual)
M.Hirano, K. Miura, M. Yamane, N. Ohtsu, Fabrication of antibacterial nanopillars
on stainless steel surface, 11th World Biomaterials Congress, WBC 2020
(12/11〜15, Virtual)
N. Ohtsu, T. Kawakami, Y. Konaka, K. Kuroda, Establishment of fractional
determination process of adsorbed proteins on titanium surface using SDS-PAGE,
11th World Biomaterials Congress, WBC 2020 (12/11〜15, Virtual)
N. Ohtsu, M. Gotoh, Y. Kohari, Y. Shimotori, T.-Y. Chiou, Y. Nagata, H.
Arai, M. Murata, Production of antimicrobial agent from a peppermint herbal
water, International Conference on Functional Materials and Chemical Engineering,
ICFMCE 2019 (12/15〜17, Bangkok, Thailand)
N. Ohtsu, T. Kawakami, Y. Konaka, K. Kuroda,Fractional analytical procedure
for adsorbed proteins onto a material surface, International Conference
on Materials and Systems for Sustainability, ICMaSS 2019 (11/1〜3, Nagoya,
Japan)
R. Kuroda, K. Kuroda, M. Okido, K. Yamaguchi, N. Ohtsu, Antibacterial Properties
of Ti Surface Using Metallic Ions Adsorption, International Conference
on Materials and Systems for Sustainability, ICMaSS 2019 (11/1〜3, Nagoya,
Japan)
K. Yamasaki, K. Takiguchi, S. Komai, N. Ohtsu, Surface characteristics
and Ni ion release behavior of anodized NiTi alloy surface using the mixed
electrolyte comprising HNO3 and H3PO4 , International Conference on Materials
and Systems for Sustainability, ICMaSS 2019 (11/1〜3, Nagoya, Japan)
K. Miura,M. Yamane, N. Ohtsu, Phase control of the plasma-nitrided SUS316
surface by N2 and H2 gas mixture ratio, International Conference on Materials
and Systems for Sustainability, ICMaSS 2019 (11/1〜3, Nagoya, Japan)
N. Ohtsu, M. Oku, K. Wagatsuma, XPS spectra of clean metallic silicide
surfaces obtained by in-situ fracture, European Conference on Application
of Surface and Interface Analysis, ECASIA 2019 (9/16〜20, Dresden, Germany)
T. Kawakami, H. Sawagucti, T. Syouji, N. Ohtsu, Effect of the surface chemical
state on competitive protein adsorption on titanium surface : A combinational
analysis using SDS-PAGE and XPS, European Conference on Application of
Surface and Interface Analysis, ECASIA 2019 (9/16〜20, Dresden, Germany)
S. Komai, M. Hirano, N. Ohtsu, Characterization of strontium-contained
apatite layer fabricated using calcium-phosphate slurry processing, European
Conference on Application of Surface and Interface Analysis, ECASIA 2019
(9/16〜20, Dresden, Germany)
K. Yamaguchi, Y. Funane, Y. Konaka, N. Ohtsu, Characteristics of anodic
oxide layer on titanium substrate using nitrate electrolyte in various
alcohols as solvent, European Conference on Application of Surface and
Interface Analysis, ECASIA 2019 (9/16〜20, Dresden, Germany)
M. Hirano, M. Yamane, N. Ohtsu, Hydrophilic properties of plasma-treated
titanium surface : Effect of gas composition and discharge modes, European
Conference on Application of Surface and Interface Analysis, ECASIA 2019
(9/16〜20, Dresden, Germany)
K. Takiguchi, M. Yamane, N. Ohtsu, Surface modification of pure iron through
a focused pulse Nd: YAG laser irradiation in nitrogen atmosphere, European
Conference on Application of Surface and Interface Analysis, ECASIA 2019
(9/16〜20, Dresden, Germany)
S. Komai, M. Hirano, N. Ohtsu, Preparation of strontium-doped apatite layer
on titanium substrate through calcium phosphate slurry processing and ion
release from the layer, International Symposium for Advanced Materials
Research, ISAMR 2019 (8/22〜25, Kaohsiung, Taiwan)
K. Takuguchi, K. Yamasaki, N. Ohtsu, Effect of anion species and concentration
in electrolyte on NiTi anodization, International Symposium for Advanced
Materials Research, ISAMR 2019 (8/22〜25, Kaohsiung, Taiwan)
K. Yamaguchi, Y. Funane, N. Ohtsu, Comparison of anodized layer on titanium
using nitrate electrolyte in various alcohol solvents for investigating
layer growth mechanism, International Symposium for Advanced Materials
Research, ISAMR 2019 (8/22〜25, Kaohsiung, Taiwan)
(Invited) N. Ohtsu , Simple chemical treatment process to give osteoconductivity
and antibacterial efficacy on titanium implant , International Symposium
for Advanced Materials Research, ISAMR 2019 (8/22〜25, Kaohsiung, Taiwan)
N. Ohtsu, Y. Hirano, K. Yamaguchi, K. Yamasaki, Surface characteristics,
Ni ion release, and antibacterial efficacy of anodized NiTi alloy using
HNO3 electrolyte of various concentrations, International Conference on
Applied Surface Science, ICASS 2019 (6/17〜20, Pisa, Italy)
K. Yamaguchi, Y. Konaka, N. Ohtsu, Fabrication of a photocatalytic antibacterial
layer on a Ti material through anodization with nitrate/glycerol electrolyte,
Anodizing Science Technology, AST 2019 (6/2〜5, Awaji, Japan)
N. Ohtsu, Y. Hirano, K. Takiguchi, K. Yamasaki, Oxide layer growth on nickel-titanium
alloy through anodization , Anodizing Science Technology, AST 2019 (6/2〜5,
Awaji, Japan)
N. Ohtsu, T.Kuji, M. Hirano, Roles of Anodic Oxide Layer on the Improvement
of Cellular Response of Titanium Implan, Pacific Rim Symposium on Surface,
Coatings & Interface, Pacsurf 2018 (12/2〜6, Waikoloa, Hawaii)
N. Ohtsu, Y. Hirano, H. Arai, Control of Ni ion release from NiTi shape
memory alloy using anodization in HNO3 electrolyte, 18th Asia Pacific Corrosion
Control COnference, APCCC-18 (11/5〜9, Pattaya, Thailand)
N. Ohtsu, Y. Hirano, Corrosion behavior of nickel-titanium alloy with TiO2
layer formed via anodization in HNO3 electrolytes, The 9th Vacuum and Surface
Science Conferene of Asia and Australia, VASSCAA-9 (8/13〜16, Sydney, Australia)
K. Sakamoto, F. Hayashi, N. Ohtsu, Formation of Ni-free oxide layer on
NiTi alloy by a combination of chemical and thermal treatments, THERMEC'2018
-International Conference on processing & manufacturing of advanced
materials (7/8〜13, Paris, France)
(Invited) N. Ohtsu, T. Kuji, M. Hirano, Effects of processing voltage on cellular
response of titanium anodized in phosphoric acid electrolyte, THERMEC'2018
-International Conference on processing & manufacturing of advanced
materials (7/8〜13, Paris, France)
N. Ohtsu, Y. Kakuchi, T. Ohtsuki, Y. Yokoiwa, Antibacterial efficacy of
hydroxyapatite coating including Zn formed by chemical solution deposition,
2nd International Conference on Applied Surface Science (6/12〜15, Dalian,
China)
N. Ohtsu, Y. Hirano, Comparison of nickel-titanium alloy surface anodized
in phosphoric- and sulfuric-acid electrolytes, 17th European Conference
on Applications of Surface and Interface Analysis (9/24〜29, Montpellier,
France)
(Invited) N. Ohtsu, Y. Kakuchi, Y. Yoshida, Antibacterial hydroxyapatite coating
on titanium via a simple chemical treatment process using calciunm phosphate
slurry, 18th International Union of Materials Research Society - Internationa
Conference in Asia (11/5〜9, Taipei, Taiwan)
Y. Hirano, N. Ohtsu, Effect of HNO3 concentration on the surface morphology
and layer thickness of the anodic oxide layer on NiTi alloy, 18th International
Union of Materials Research Society - Internationa Conference in Asia (11/5〜9,
Taipei, Taiwan)
M. Bai, N. Ohtsu, Effect of water addition to NH4NO3/ethylene glycol electrolyte
on the growth of anodic layer on titanium, 18th International Union of
Materials Research Society - Internationa Conference in Asia (11/5〜9, Taipei,
Taiwan)
N. Ohtsu, H. Arai, Calcium-phosphate slurry processing: a novel chemical
treatment technique to activate osteogenesis on titanium, 10nd World Biomaterials
Congress (5/17〜22, Montreal, Canada)
N. Ohtsu, T. Kozuka, M. Yamane, K. Ishikawa, Improvement of high temperature
stability of Pd-coated Nb using surface plasma nitriding, 15th International
Symposium on Metal-Hydrogen System (8/7〜12, Interlaken, Switzerland)
Y. Hirano, Y. Kakuchi, N. Ohtsu, A chemically stable TiO2 layer formation
on NiTi alloy by electrochemical process, Pure and Applied Chemistry International
Conference 2017 (2/2〜3, Bangkok, Thai)