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Maki Ashida

  (蘆田 茉希)

Profile Information

Affiliation
Assistant Professor, Faculty of Science and Technology Department of Science and Technology , Seikei University
Degree
博士（工学）
J-GLOBAL ID
201801006443704147
researchmap Member ID
7000025465

Research Interests

 1

Research Areas

 1

Research History

 8
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Awards

 24
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Papers

 51
  • Taichi Akutsu, Maki Ashida, Shotaro Hisano, Chie Ashida, Eric Des Marias, Shizuka Sutani
    Arts & Communication, 2(2) 1782-1782, May 6, 2024  Peer-reviewed
    Despite the existing research on flow in music education, there remains a lack of researches in understanding children’s flow experiences in the context of playing musical instrument, electronic technological instruments, and other traditional instruments. This study investigates the observable flow experience among young children during their interactions with musical instrument digital interface instruments, violins, and bell-like instruments. The research employed a case study approach, with 20 children aged two to nine (11 females and nine males) participating in the study. In the study, we, as practitioner-researchers, offered workshops for children to experience a variety of traditional and non-traditional musical instruments. Throughout the study, researchers collected 89 video clips for analysis, using four cameras operated by four assistants who were trained to capture children’s flow in a musical context. These monthly sessions, each lasting an average of 60 min, began with the first session dedicated to capturing the very first encounter of children with various musical devices, instruments, and materials. Custodero’s Flow Indicators in Musical Activities captured children’s flow experiences during workshops. The findings included interpretations of the children’s flow experiences as they explored different devices, instruments, and materials, with a particular emphasis on accessibility and developmental considerations within the social context of children’s musical flow.
  • Kaveh Edalati, Anwar Q. Ahmed, Saeid Akrami, Kei Ameyama, Valery Aptukov, Rashid N. Asfandiyarov, Maki Ashida, Vasily Astanin, Andrea Bachmaier, Victor Beloshenko, Elena V. Bobruk, Krzysztof Bryła, José María Cabrera, Amanda P. Carvalho, Nguyen Q. Chinh, In-Chul Choi, Robert Chulist, Jorge M. Cubero-Sesin, Gregory Davdian, Muhammet Demirtas, Sergiy Divinski, Karsten Durst, Jiri Dvorak, Parisa Edalati, Satoshi Emura, Nariman A. Enikeev, Ghader Faraji, Roberto B. Figueiredo, Ricardo Floriano, Marjan Fouladvind, Daniel Fruchart, Masayoshi Fuji, Hiroshi Fujiwara, Marcell Gajdics, Diana Gheorghe, Łukasz Gondek, Joaquín E. González-Hernández, Alena Gornakova, Thierry Grosdidier, Jen Gubicza, Dmitry Gunderov, Liqing He, Oscar Fabian Higuera, Shoichi Hirosawa, Anton Hohenwarter, Zenji Horita, Jelena Horky, Yi Huang, Jacques Huot, Yoshifumi Ikoma, Tatsumi Ishihara, Yulia Ivanisenko, Jae-il Jang, Alberto M. Jorge, Mie Kawabata-Ota, Megumi Kawasaki, Tarek Khelfa, Junya Kobayashi, Lembit Kommel, Anna Korneva, Petr Kral, Natalia Kudriashova, Shigeru Kuramoto, Terence G. Langdon, Dong-Hyun Lee, Valery I. Levitas, Cong Li, Hai-Wen Li, Yongtao Li, Zheng Li, Huai-Jun Lin, Klaus-Dieter Liss, Ying Liu, Diana Maritza Marulanda Cardona, Kenji Matsuda, Andrey Mazilkin, Yoji Mine, Hiroyuki Miyamoto, Suk-Chun Moon, MullerTimo Müller, Jairo Alberto Muñoz, Maxim Yu. Murashkin, Muhammad Naeem, Marc Novelli, Dániel Olasz, Reinhard Pippan, Vladimir V. Popov, Elena N. Popova, Gencaga Purcek, Patricia de Rango, Oliver Renk, Delphine Retraint, Ádám Révész, Virginie Roche, Pablo Rodriguez-Calvillo, Liliana Romero-Resendiz, Xavier Sauvage, Takahiro Sawaguchi, Hadi Sena, Hamed Shahmir, Xiaobin Shi, Vaclav Sklenicka, Werner Skrotzki, Nataliya Skryabina, Franziska Staab, Boris Straumal, Zhidan Sun, Maciej Szczerba, Yoichi Takizawa, Yongpeng Tang, Ruslan Z. Valiev, Alina Vozniak, Andrei Voznyak, Bo Wang, Jing Tao Wang, Gerhard Wilde, Fan Zhang, Meng Zhang, Peng Zhang, Jianqiang Zhou, Xinkun Zhu, Yuntian T. Zhu
    Journal of Alloys and Compounds, 174667-174667, May, 2024  Peer-reviewed
  • Maki Ashida
    Materials Transactions, 64(8) 1784-1790, Jul, 2023  Peer-reviewedLead authorCorresponding author
    Ti6Al7Nb alloys have been widely used in the medical field, particularly in artificial hip joints, spinal fixators, and dental implants, owing to their light weight, low toxicity, and superior corrosion resistance. Grain refinement through a severe plastic deformation process under high pressure, such as high-pressure torsion (HPT) or high-pressure sliding, is widely employed for strengthening metallic materials. This overview presents the recent advances in the effect of HPT on the mechanical properties of the Ti6Al7Nb alloy. This alloy was grain-refined through HPT under applied pressures of 2 and 6 GPa, and the results revealed that the alloy subjected to HPT processing at 6 GPa exhibited a higher strength. To inhibit the decrease in the total elongation of the alloy, the number of revolutions in the HPT process was set to moderate. The tensile properties achieved after HPT processing were found to be dependent on the initial microstructure before the HPT treatment. Furthermore, an alloy with a bimodal equiaxed and acicular structure was subjected to grain refinement via the HPT process. The results revealed that fragmentation of the acicular structure during HPT further increased the strength. Moreover, the HPT-processed Ti6Al7Nb alloy exhibited superplasticity. It was thus confirmed that grain refinement by HPT is an effective method for strengthening the Ti6Al7Nb alloy, which is advantageous for medical applications.
  • Yusuke Tsutsumi, Harumi Tsutsumi, Tomoyo Manaka, Peng Chen, Maki Ashida, Hideki Katayama, Takao Hanawa
    COATINGS, 13(3) 627, Mar, 2023  Peer-reviewed
    A customized micro-arc oxidation (MAO) treatment technique was developed to obtain antibacterial properties with no toxicity on Ti surfaces. A two-step MAO treatment was used to fabricate a specimen containing both Ag and Zn in its surface oxide layer, and the optimal incorporation conditions were determined. Surface characterization by EDS was performed followed by the antibacterial properties against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) and osteogenic cell compatibility evaluations. In addition, metal ion release tests were performed to evaluate the contents of Ag and Zn and the ion release behavior in order to simulate practical usage. MAO-treated specimens prepared using proper concentrations of Ag and Zn (0.5Ag-5Zn: 0.5 mM AgNO3 and 5.0 mM ZnCl, respectively) exhibited excellent antibacterial properties against E. coli and S. aureus and no toxicity to MC3T3-E1 in antibacterial and cytotoxic evaluations, respectively. The antibacterial property of 0.5Ag-5Zn against S. aureus was sustained even after two months of immersion in physiological saline, simulating the in vivo environment.
  • Tomoyo Manaka, Yusuke Tsutsumi, Yukyo Takada, Peng Chen, Maki Ashida, Kotaro Doi, Hideki Katayama, Takao Hanawa
    MATERIALS TRANSACTIONS, 64(1) 131-137, Jan, 2023  Peer-reviewed
    In orthopedics, occasionally, different types of metals are used in applications in which they are in contact with each other. However, few studies have electrochemically investigated the galvanic corrosion of orthopedic implants formed of different metals. In this study, galvanic corrosion of Ti-6Al-4V ELI alloy, Co-Cr-Mo alloy, and 316L type stainless steel, which are used in orthopedics, and a newly developed Zr-1Mo alloy as a low-magnetic susceptibility material was evaluated in saline. Coupling of the Ti-6Al-4V ELI and Co-Cr-Mo alloys did not exhibit localized corrosion and maintained highly stable passive films. Coupling of the 316L type stainless steel and Co-Cr-Mo alloy, temporary localized corrosion occurred. Similarly, coupling of the Zr-1Mo and Co-Cr-Mo alloys, temporary localized corrosion occurred. However, both of 316L type stainless steel and Zr-1Mo alloy were finally repassivated spontaneously with the immersion time. The degree of the localized corrosion of the Zr-1Mo alloy was smaller than that of 316L type stainless steel. No galvanic current was observed when the Ti-6Al-4V ELI and Co-Cr-Mo alloys were coupled. A slight galvanic current flowed when 316L type stainless steel or the Zr-1Mo alloy was coupled with the other alloys; however, the galvanic current with the Zr-1Mo alloy coupling recovered to zero after a certain period owing to repassivation. No metal ions were detected from the couplings with Zr-1Mo
  • Yuzuki Eda, Tomoyo Manaka, Takao Hanawa, Peng Chen, Maki Ashida, Kazuhiko Noda
    Surface and Interface Analysis, 54(8) 892-898, Aug, 2022  Peer-reviewed
    Titanium (Ti) is always covered by thin passive films. Thus, valence band (VB) spectra, obtained using X-ray photoelectron spectroscopy (XPS), are superpositions of the VB spectra of passive films and that of the metallic Ti substrate. In this study, to obtain the VB spectra only of passive films, angular resolution (for eliminating the substrate Ti contribution) and argon ion sputtering (for removing passive films) were used along with XPS. The passive film on Ti was determined to consist of a very thin TiO2 layer with small amounts of Ti2O3, TiO, hydroxyl groups, and water with a thickness of 5.9 nm. The VB spectra of Ti were deconvoluted into four peak components: a peak at similar to 1 eV, attributed to the Ti metal substrate; a broad peak in the 3-10 eV range, mainly attributed to O 2p (similar to 6 eV) and O 2p-Ti 3d hybridized states (similar to 8 eV), owing to the pi (non-bonding) and sigma (bonding) orbitals in the passive oxide film; and a peak at similar to 13 eV, attributed to the 3 sigma orbital of O 2p as OH- or H2O. The VB region spectrum between approximately 3 and 14 eV from Ti is originating from the passive film on Ti. In particular, characterization of VB spectrum obtained with a takeoff angle of less than 24 degrees is effective to obtain VB spectrum only from the passive film on Ti. The property as n-type semiconductor of the passive film on Ti is probably higher than that of rutile TiO2 ceramics.
  • Maki Ashida, Minami Hanai, Peng Chen, Takao Hanawa
    MATERIALS TRANSACTIONS, 63(6) 948-956, Jun 1, 2022  Peer-reviewedLead authorCorresponding author
  • Hiromitsu SATO, Peng CHEN, Maki ASHIDA, Yusuke TSUTSUMI, Hiroyuki HARADA, Takao HANAWA
    Dental Materials Journal, 41(3) 421-428, May 25, 2022  Peer-reviewed
  • Tomoyo Manaka, Yusuke Tsutsumi, Peng Chen, Maki Ashida, Hideki Katayama, Takao Hanawa
    Journal of The Electrochemical Society, 168(12) 121505-121505, Dec 1, 2021  Peer-reviewed
    An electrochemical surface treatment was developed to visualize the corrosion-inducing inclusions of Zr in chloride environments. Pure Zr and Zr alloy (Zr–0.5O–0.5C) were evaluated in this study. The electrochemical surface treatment consisted of repeated galvanostatic anodic polarization and potentiostatic cathodic polarization. After the electrochemical surface treatment, only one brittle and non-conductive shell of Zr oxide was observed at the corrosion initiation site on the tested surface. The corrosion-inducing inclusions were found inside the corrosion pit under the optimum polarization conditions. At the corrosion initiation site on pure Zr, the area inside the corrosion pit contained larger amounts of O, C, and Si than the surrounding matrix. In the case of the Zr-0.5O–0.5C alloy, relatively larger inclusions were observed after the treatment. Extremely large amounts of Si, together with O and C, were present in the inclusions. The inclusions that induced localized corrosion on the pure Zr and Zr-0.5O–0.5C specimens were found to be precipitated, involving the specific aggregation of Si. The surface treatment developed in this study is expected to be utilized as a powerful tool to elucidate the localized corrosion mechanism of Zr in chloride environments.
  • Tsutsumi Y, Ishimoto T, Oishi T, Manaka T, Chen P, Ashida M, Doi K, Katayama H, Hanawa T, Nakano T
    Additive Manufact, 45 102066, Sep, 2021  Peer-reviewed
    Improvement of corrosion resistance of austenitic 316L stainless steel via laser powder bed fusion (LPBF) is currently a prominent research topic; however, the effects of crystallographic texture and the related grain boundary density on the corrosion resistance of LPBF-fabricated parts have not been elucidated. For biomedical applications, crystallographic texture control from a single crystalline-like to randomly oriented polycrystalline microstructure is highly attractive for optimizing the mechanical properties (particularly the Young's modulus) of implants. An investigation of the impacts of crystallographic planes and grain boundaries exposed to the biological environment on corrosion behavior is necessary. 316L stainless steels with different crystallographic textures and grain boundary densities were successfully fabricated via LPBF. The corrosion resistances of the LPBF-fabricated specimens were comprehensively assessed by anodic polarization, dissolution, and crevice corrosion repassivation tests. The LPBF-fabricated specimens showed extremely high pitting potentials in the physiological saline compared with the commercially available counterparts, and importantly, excellent pitting corrosion resistance was observed irrespective of the crystallographic planes and grain boundary density exposed. Moreover, the LPBF-fabricated specimens did not show metastable pitting corrosion even in an accelerated test using an acid solution. The repassivation behavior of the specimens was not affected by LPBF. Such a drastic improvement in the corrosion resistances of the LPBF-fabricated specimens might be attributed to suppression of inclusion coarsening owing to the rapid cooling rate during solidification in LPBF. By using LPBF, the desired crystallographic texture can be introduced based on the desired mechanical properties without concern for corrosiveness.
  • Masaya Shimabukuro, Tomoyo Manaka, Yusuke Tsutsumi, Kosuke Nozaki, Chen Peng, Maki Ashida, Akiko Nagai, Takao Hanawa
    Zairyo-to-Kankyo, 70(8) 265-270, Aug 10, 2021  Peer-reviewed
  • Tsutsumi H, Tsutsumi Y, Shimabukuro M, Manaka T, Chen P, Ashida M, Ishikawa K, Katayama H, Hanawa T
    Coatings, 11(7) 798-798, Jul, 2021  Peer-reviewed
    Recently, biofilm formation caused by bacterial adhesion and colonization has been recognized as the major cause of failure in orthopedic and dental implant surgeries. In this study, a customized micro-arc oxidation (MAO) treatment technique was developed to obtain desirable antibacterial properties on Ti surfaces. The two-step MAO treatment was applied in the fabrication of specimens with Ag and with/without Zn in their surface oxide layer. In order to simulate practical usage, surface analyses and immersion tests were performed to evaluate the incorporation of Ag and Zn into the resulting oxide layer and ion release behavior, respectively. Additionally, the antibacterial properties of the specimens after long-term immersion in physiological saline were evaluated using Gram-negative facultative anaerobic bacteria. The MAO-treated specimens containing Ag and Zn exhibited excellent antibacterial properties against Escherichia coli, which were sustained even after 6 months of immersion in physiological saline to simulate practical usage. Moreover, the Ag ions released from the surface oxide indicate the antibacterial properties of the specimen in the early stage, while the release of the corrosion products of Zn demonstrates its antibacterial properties in the later stage.
  • Manaka T, Tsutsumi Y, Ashida M, Chen P, Katayama H, Hanawa T
    Mater Trans, 62(6) 788-796, Jun, 2021  Peer-reviewed
    An electrochemical surface treatment technique was developed in this study to improve the localized corrosion resistance of zirconium in a chloride ion environment. A combination of anodic and cathodic polarization cycles was applied to induce the selective dissolution of the inclusions that could potentially initiate the localized corrosion of zirconium. Shallow dips were observed on the specimen surface after the treatment, thereby indicating the dissolution of the inclusions. The electrochemical treatments via galvanostatic anodic polarization and potentiostatic cathodic polarization in concentrated phosphate-buffered saline resulted in a high pitting potential of greater than 2V in a simulated body fluid. This indicated that the devised technique realized a significant increase in the localized corrosion resistance of the treated Zr.
  • Shimabukuro M, Tsutsumi H, Tsutsumi Y, Manaka T, Chen P, Ashida M, Ishikawa K, Katayama H, Hanawa T
    Dent Mater J, 40(3) 592-598, May, 2021  Peer-reviewed
    A customized micro arc oxidation (MAO) treatment technique was developed to obtain desirable antibacterial properties on titanium surfaces. The two-step MAO treatment was applied to fabricate a specimen containing both Ag and Zn in its surface oxide layer. Surface analyses and metal-ion release tests were performed to evaluate the presence of Ag and Zn and the ion release behavior for simulating practical usage, respectively. Additionally, the antibacterial properties of the specimens were also evaluated using gram-negative facultative anaerobic bacteria. The MAO-treated specimens containing both Ag and Zn showed excellent antibacterial properties against Escherichia coli, and the properties were sustained even after 28 days of immersion in physiological saline to simulate the living environment.
  • Hiji A, Hanawa T, Yokoi T, Chen P, Ashida M, Kawashita M
    Langmuir, 37(12) 3597-3604, Mar, 2021  Peer-reviewed
  • Tomoyo Manaka, Yusuke Tsutsumi, Maki Ashida, Peng Chen, Hideki Katayama, Takao Hanawa
    Zairyo-to-Kankyo, 69(11) 307-314, Nov 10, 2020  
  • Tsutsumi Y, Muto I, Nakano S, Tsukada J, Manaka T, Chen P, Ashida M, Sugawara Y, Shimojo M, Hara N, Katayama H, Hanawa T
    J Electrochem Soc, 167(14) 141507-141507, Nov, 2020  Peer-reviewed
  • 真中智世, 堤 祐介, 蘆田茉希, 陳 鵬, 片山英樹, 塙 隆夫
    材料と環境, 69(11) 307-314, Nov, 2020  Peer-reviewed
  • Hiji A, Hanawa T, Shimabukuro M, Chen P, Ashida M, Ishikawa K
    Surf Interface Anal, 53(2) 185-193, Oct, 2020  Peer-reviewed
  • Shimabukuro M, Tsutsumi Y, Nozaki K, Chen P, Yamada R, Ashida M, Doi H, Nagai A, Hanawa T
    Dent Materi J, 39(4) 639-647, Aug, 2020  Peer-reviewed
  • Shimabukuro M, Hiji A, Manaka T, Nozaki K, Chen P, Ashida M, Tsutusmi Y, Nagai A, Hanawa T
    J Funct Biomater, 11(2) 44-44, Jun, 2020  Peer-reviewed
    Recently, silver (Ag) and copper (Cu) have been incorporated into a titanium (Ti) surface to realize their antibacterial property. This study investigated both the durability of the antibacterial effect and the surface change of the Ag- and Cu-incorporated porous titanium dioxide (TiO2) layer. Ag- and Cu-incorporated TiO2 layers were formed by micro-arc oxidation (MAO) treatment using the electrolyte with Ag and Cu ions. Ag- and Cu-incorporated specimens were incubated in saline during a period of 0–28 days. The changes in both the concentrations and chemical states of the Ag and Cu were characterized using X-ray photoelectron spectroscopy (XPS). The durability of the antibacterial effects against Escherichia coli (E. coli) were evaluated by the international organization for standardization (ISO) method. As a result, the Ag- and Cu-incorporated porous TiO2 layers were formed on a Ti surface by MAO. The chemical state of Ag changed from Ag2O to metallic Ag, whilst that of Cu did not change by incubation in saline for up to 28 days. Cu existed as a stable Cu2O compound in the TiO2 layer during the 28 days of incubation in saline. The concentrations of Ag and Cu were dramatically decreased by incubation for up to 7 days, and remained a slight amount until 28 days. The antibacterial effect of Ag-incorporated specimens diminished, and that of Cu was maintained even after incubation in saline. Our study suggests the importance of the time-transient effects of Ag and Cu on develop their antibacterial effects.
  • Shimabukuro M, Manaka T, Tsutsumi Y, Nozaki K, Chen P, Ashida M, Nagai A, Hanawa T
    Mater Trans, 61(6) 1143-1148, Jun, 2020  Peer-reviewed
  • Ashida M, Tsutsumi Y, Homma K, Chen P, Shimojo M, Hanawa T
    Mater Trans, 61(4) 776-781, Mar, 2020  Peer-reviewedLead author
  • Masaya Shimabukuro, Yusuke Tsutsumi, Risa Yamada, Maki Ashida, Peng Chen, Hisashi Doi, Kosuke Nozaki, Akiko Nagai, Takao Hanawa
    ACS BIOMATERIALS SCIENCE & ENGINEERING, 5(11) 5623-5630, Nov, 2019  Peer-reviewed
    Recently, the problem of infection on implanted devices caused by the formation of biofilms has been recognized. Surface treatment to prevent the initial stages of bacterial adhesion and subsequent bacterial growth is the only possible solution against such infection. In this study, simple electrochemical treatment was used for introducing silver, an antibiotic agent, on the titanium surface. A porous oxide layer containing small amounts of silver was formed on the metal of the substrate. This was done by microarc oxidation using the electrolyte with silver nitrate. The porous oxide layer was almost amorphous with a small fraction of anatase phase. The samples prepared using the electrolyte containing 0.04 mM or a higher concentration of silver nitrate showed an excellent antibacterial effect against both E. coli and S. aureus. However, the proliferation of osteoblast-like cells in the samples was not affected when a concentration of 0.5 mM or lower was used. Moreover, samples containing silver showed no harmful effects on the process of bone differentiation. Furthermore, the calcification process of the cells on the samples treated with and without silver were more promoted than that on untreated Ti. Thus, we found that it is possible to use this optimum concentration of silver to realize the conflicting biofunctions: its antibacterial property and osteogenic cell compatibility.
  • Masaya Shimabukuro, Yusuke Tsutsumi, Kosuke Nozaki, Peng Chen, Risa Yamada, Maki Ashida, Hisashi Doi, Akiko Nagai, Takao Hanawa
    Coatings, 9(11) 705-705, Oct 29, 2019  Peer-reviewed
    This study investigated the time transient effect of zinc (Zn) in the porous titanium dioxide formed by micro-arc oxidation (MAO) treatment routinely performed for Zn-containing electrolytes. The aim of our analysis was to understand the changes in both the chemical and biological properties of Zn in physiological saline. The morphology of the Zn-incorporated MAO surface did not change, and a small amount of Zn ions were released at early stages of incubation in saline. We observed a decrease in Zn concentration in the oxide layer because its release and chemical state (Zn2+ compound to ZnO) changed over time during incubation in saline. In addition, the antibacterial property of the Zn-incorporated MAO surface developed at late periods after the incubation process over a course of 28 days. Furthermore, osteogenic cells were able to proliferate and were calcified on the specimens with Zn. The changes related to Zn in saline had non-toxic effects on the osteogenic cells. In conclusion, the time transient effect of Zn in a porous titanium dioxide layer was beneficial to realize dual functions, namely the antibacterial property and osteogenic cell compatibility. Our study suggests the importance of the chemical state changes of Zn to control its chemical and biological properties.
  • Shimabukuro M, Ito H, Tsutsumi Y, Nozaki K, Chen P, Yamada R, Ashida M, Nagai A, Hanawa T
    Metals, 9(11) 1145-1145, Oct, 2019  Peer-reviewed
    The effects of Ti, Nb, Ta, Zr, and Ag on cellular and bacterial adhesion were investigated in this study. Moreover, the relationships between surface compositions, metal ion release behaviors, and biological responses were examined. As a result, MC3T3-E1 cells and S. aureus were able to better attach to Ti and Zr rather than the Nb and Ta specimens. For the Ag specimen, the amount of Ag ions released into Hanks’ solution was the largest among all the specimens. Cellular and bacterial adhesion onto the Ag specimen was inhibited compared with the other specimens, because of Ag ion release. Alternatively, Nb and Ta specimens exhibited specific biological responses. Cellular adhesion on Nb and Ta specimens was similar to that on Ti, while bacterial adhesion on Nb and Ta specimens was inhibited compared with that on Ti. This study proved that Nb and Ta inhibited bacterial adhesion and exhibited no harmful effects on cellular adhesion. In addition, these results indicate that the passive layer on Nb and Ta plays a key role in the inhibition of bacterial adhesion.
  • Iku KAWABATA, Haruki IMAI, Zuisei KANNO, Akemi TETSUMURA, Yusuke TSUTSUMI, Hisashi DOI, Maki ASHIDA, Tohru KURABAYASHI, Takao HANAWA, Toru YAMAMOTO, Takashi ONO
    Dental Materials Journal, 38(4) 638-645, Jul 26, 2019  Peer-reviewed
    Differences in the volumes of artifacts caused by variously shaped titanium objects on magnetic resonance imaging (MRI) were evaluated. Spherical-, square cubic-, and regular tetrahedron-shaped isotropic, and elongated spherical-, elongated cubic-, and elongated tetrahedron-shaped anisotropic objects, with identical volumes, were prepared. Samples were placed on a nickel-doped agarose gel phantom and covered with nickel-nitrate hexahydrate solution. Three-Tesla MR images were obtained using turbo spin echo and gradient echo sequences. Areas with ±30% of the signal intensity of the standard background value were considered artifacts. Sample volumes were deducted from these volumes to calculate the total artifact volumes. Isotropic samples had similar artifact volumes. For anisotropic samples, the artifact volume increased in proportion with the normalized projection area. MRI artifact size can be reduced by high anisotropic designs, and by positioning the long axis of the metal device as parallel as possible to the magnetic field axis.
  • Watanabe K, Ashida M, Masuda T, Kral P, Takizawa Y, Yumoto M, Otagiri Y, Sklenicka V, Hanawa T, Horita Z
    Mater Trans, 60(9) 1785-1791, Jul, 2019  Peer-reviewedCorresponding author
    © 2019 The Japan Institute of Light Metals A Ti6Al7Nb alloy was processed by severe plastic deformation through high-pressure sliding (HPS) at room temperature for grain refinement. The microstructure consists of grains with sizes of 200300 nm in diameter having high and low angles boundaries. Superplasticity appeared with the total elongation of more than 400% and this was more likely when the tensile specimen is deformed in the direction parallel than perpendicular to the sliding direction. However, the superplastic elongation is almost the same irrespective of whether the sliding was made in the single direction or in the reversible directions as far as the total sliding distance is the same. The total elongation is invariably higher for the tensile testing at 1123 K than at the other temperatures, reaching the highest elongation of 790% at the initial strain rate of 1 © 1013 s11. The strain rate sensitivity and the activation energy for the deformation were determined to be more than 30.3 and 199 kJ/mol, respectively. The microstructural observation reveals that the ¡ phase region covers more than 85% of the tensile specimens after deformation and their grains are equiaxed in shape. It is concluded that the superplastic deformation is mainly controlled by grain boundary sliding through thermally activation by lattice diffusion.
  • Oishi M, Tsutsumi Y, Chen P, Nakaishi M, Ashida M, Doi H, Hanawa T
    Dent. Mater. J., 38(3) 496-504, Jun, 2019  Peer-reviewed
  • Chen P, Aso T, Sasaki R, Ashida M, Tsutsumi Y, Doi H, Hanawa T
    J. Biomed. Mater. Res. A, Jul, 2018  Peer-reviewed
  • Ashida M, Morita M, Tsutsumi Y, Nomura N, Doi H, Chen P, Hanawa T
    Metals, 8(6) 454, Jun, 2018  Peer-reviewedLead author
  • Oishi M, Tsutsumi Y, Chen P, Ashida M, Doi H, Hanawa T
    Surf Interface Anal, 50(5) 587-591, May, 2018  Peer-reviewed
  • Watanabe K, Ashida M, Masuda T, Kral P, Takizawa Y, Yumoto M, Otagiri Y, Sklenicka V, Hanawa T, Horita Z
    J Japan Instit Light Met, 68(1) 9-15, Jan, 2018  Peer-reviewed
    © 2018 The Japan Institute of Light Metals. A Ti-6Al-7Nb alloy was processed by severe plastic deformation through high-pressure sliding (HPS) at room temperature for grain refinement. The microstructure consists of grains with sizes of 100-200 nm in diameter having high and low angles boundaries. Superplasticity appeared with the total elongation of more than 400% and this was more likely when the tensile specimen is deformed in the direction parallel than perpendicular to the sliding direction. However, the superplastic elongation is almost the same irrespective of whether the sliding was made in the single direction or in the reversible directions as far as the total sliding distance is the same. The total elongation is invariably higher for the tensile testing at 1123 K than at the other temperatures, reaching the highest elongation of 790% at the initial strain rate of 1×10-3 s-1. The strain rate sensitivity and the activation energy for the deformation were determined to be more than ∼0.3 and 200 kJ/mol, respectively. The microstructural observation reveals that the α phase region covers more than 85% of the tensile specimens after deformation and their grains are equiaxed in shape. It is concluded that the superplastic deformation is mainly controlled by grain boundary sliding through thermally activation by lattice diffusion.
  • Chen P, Aso T, Sasaki R, Tsutsumi Y, Ashida M, Doi H, Hanawa T
    J Biomed Nanotechnol, 13(3) 324-336, Mar, 2017  Peer-reviewed
  • Tsustumi Y, Doi H, Nomura N, Ashida M, Chen P, Kawasaki A, Hanawa T
    Mater. Trans., 57(12) 2033-2040, Dec, 2016  Peer-reviewed
    <p>Air-formed surface oxide films on four types of Co-Cr- alloys were characterized using X-ray photoelectron spectroscopy (XPS) and five types of Co-Cr alloys were anodically polarized, to identify the effects of the addition of N, Mo, and W to Co-Cr alloys containing high Cr on the surface composition and corrosion resistance. Co-20Cr-15W-10Ni (ASTM F90), Co-30Cr-6Mo, Co-33Cr-5Mo-0.3N, and Co-33Cr-9W-0.3N were employed for XPS and the above four alloys and another Co-30Cr-6Mo (ASTM F75) were employed for anodic polarization. The surface oxide film on the Co-Cr alloys consisted of oxide species of Co, Cr, Mo, W and/or Ni contains a large amount of OH− with a thickness of 2.6–3.2 nm. Cations existed in the oxide as Co2+, Cr3+, Mo4+, Mo5+, Mo6+, W6+ and Ni2+. Cr and Mo are enriched and Co and Ni are depleted in the surface oxide film. W was enriched in the case of Co-20Cr-15W-10Ni but depleted in the case of Co-33Cr-9W-0.3N. On the other hand, Cr, Mo, W and Ni were enriched and Co was depleted in the substrate alloy just under the surface oxide film in the polished alloy. During rapid formation of the surface oxide film, Cr was preferentially oxidized and the oxidation of Co and Ni delayed, according to the oxidation and reduction potentials of these elements. The Co-Cr alloys essentially have high localized corrosion resistance that is not easily affected by a small change of composition. Co-33Cr-5Mo-0.3N shows higher corrosion resistance compare than conventional Co-Cr alloys.</p>
  • Tsutsumi Y, Ashida M, Nakahara K, Serizawa A, Doi H, Grandini CR, Rocha LA, Hanawa T
    Mater. Trans., 57(12) 2015-2019, Dec, 2016  Peer-reviewed
    © 2016 The Japan Institute of Metals and Materials. Ti-15Zr-7.5Mo alloy was melted and its structure and mechanical properties were evaluated, followed by micro-arc oxidation (MAO) treatment to add bioactivity. Melted Ti-15Zr-7.5Mo alloy was consisted of mainly β containing of metastable α" and ω phases. The Vickers hardness of the alloy was 420 HV and larger than those of Ti-6Al-4V alloy (320 HV) and Ti-29Nb-13Ta-4.6Zr ally (TNTZ) (180 HV). The Young's modulus of the alloy was about 104-112 GPa and almost the same as that of Ti-6Al-4V alloy (113 GPa) and larger than that of TNTZ (80 GPa). The MAO treatment was performed in a mixed electrolyte of 0.1-mol L-1 calcium glycerophosphate and 0.15-mol L-1 calcium acetate with a positive maximum voltage of 400 V and a 31.2 mA cm-2 for 600 s. Porous composite oxide of Ti, Zr, and Mo containing large amounts of Ca and P was formed on Ti-15Zr-7.5Mo alloy by micro arc oxidation (MAO) treatment. Zr was preferentially enriched and Ti and Mo were depleted in the oxide layer. Pore size was larger than that of CP Ti. The ability of calcium phosphate formation of the alloy in Hanks' solution after MAO treatment was less than those of CP Ti and TNTZ. It is necessary for the alloy to conduct a chemical treatment to accelerate bone formation.
  • Chen P, Ashida M, Doi H, Tsutsumi Y, Horita Z, Hanawa T
    Mater Trans, 57(12) 2020-2025, Nov, 2016  Peer-reviewed
    <p>In this study, we evaluated the cytocompatibility of high-pressure torsion (HPT)-processed Ti-6Al-7Nb alloys. Grain size of titanium (Ti) alloys decreased from 5 µm (without HPT processing, HPT-0) to ～100 nm (at 2 GPa, HPT-2) or ～70 nm (at 6 GPa, HPT-6) through HPT processing. Cell adhesion, proliferation, and differentiation were evaluated with mouse preosteoblast (MC3T3-E1). A locomotion trend was presented by cells cultured on HPT-2 to compare with other specimens, while, an immobilization trend was presented by cells cultured on HPT-6 to compare with other specimens. Akp2 (alkaline phosphatase 2) expression was higher in cells cultured on HPT-2 than that on HPT-0 and HPT-6, indicating enhanced osteogenic differentiation. Our results demonstrate that HPT-processed Ti-6Al-7Nb alloys offer good cytocompatibility.</p>
  • Kajima Y, Takaichi A, Nakamoto T, Kimura T, Yogo Y, Ashida M, Doi H, Nomura N, Takahashi H, Hanawa T, Wakabayashi N
    J. Mech. Behav. Biomed. Mater., 59 446-458, Jun, 2016  Peer-reviewed
    We aimed to investigate the fatigue strength of Co-Cr-Mo clasps for removable partial dentures prepared by selective laser melting (SLM). The Co-Cr-Mo alloy specimens for tensile tests (dumbbell specimens) and fatigue tests (clasp specimens) were prepared by SLM with varying angles between the building and longitudinal directions (i.e., 0° (TL0, FL0), 45° (TL45, FL45), and 90° (TL90, FL90)). The clasp specimens were subjected to cyclic deformations of 0.25mm and 0.50mm for 10(6) cycles. The SLM specimens showed no obvious mechanical anisotropy in tensile tests and exhibited significantly higher yield strength and ultimate tensile strength than the cast specimens under all conditions. In contrast, a high degree of anisotropy in fatigue performance associated with the build orientation was found. For specimens under the 0.50mm deflection, FL90 exhibited significantly longer fatigue life (205,418 cycles) than the cast specimens (112,770 cycles). In contrast, the fatigue lives of FL0 (28,484 cycles) and FL45 (43,465 cycles) were significantly shorter. The surface roughnesses of FL0 and FL45 were considerably higher than those of the cast specimens, whereas there were no significant differences between FL90 and the cast specimens. Electron backscatter diffraction (EBSD) analysis indicated the grains of FL0 showed preferential close to <001> orientation of the γ phase along the normal direction to the fracture surface. In contrast, the FL45 and FL90 grains showed no significant preferential orientation. Fatigue strength may therefore be affected by a number of factors, including surface roughness and crystal orientation. The SLM process is a promising candidate for preparing tough removable partial denture frameworks, as long as the appropriate build direction is adopted.
  • DOI Hisashi, ASHIDA Maki, TSUTSUMI Yusuke, NOMURA Naoyuki, HANAWA Takao
    THE JOURNAL OF JAPANESE SOCIETY FOR DENTAL MATERIALS AND DEVICES, 35(3) 217-225, May, 2016  Peer-reviewed
    <p>The Co-Cr-Mo alloy is widely applied as a biocompatible metal, because it shows excellent strength and corrosion resistance. Especially, cobalt-chromium alloy of various types has been practically used as an alloy for dental casting. By increasing the N concentration of this alloy, the mechanical properties were improved. In addition, detailed examination also seems to be necessary on the characteristics as the concentration of Cr increases. In this study, mechanical properties and corrosion resistance were considered using a tensile test and an elution test in 1％ lactic acid when N and Cr concentrations of the Co-Cr-Mo alloy were changed. As a result, the ductility was rapidly improved in 0.2〜0.4 mass％ N alloy. Also, as the Cr concentration increased from 32 mass％, the strength increased but it became brittle when it exceeded 36％. Regarding the corrosion resistance, there was no effect of the concentration of N or Cr.</p>
  • Chen P, Nagai A, Tsutsumi Y, Ashida M, Doi H, Hanawa T
    J Biomed Mater Res A, 104(3) 639-651, Mar, 2016  Peer-reviewed
  • Tsutsumi Y, Niinomi M, Nakai M, Shimabukuro M, Ashida M, Chen P, Doi H, Hanawa T
    Metals, 6(4) 76, Mar, 2016  Peer-reviewedInvited
  • Okamoto H, Tsutsumi Y, Watanabe M, Yamakage K, Ashida M, Chen P, Doi H, Miura H, Matsumura M, Hanawa T
    Electrochemistry, 83(12) 1048-1052, Dec, 2015  Peer-reviewed
  • Tsutsumi Y, Nishisaka T, Doi H, Ashida M, Chen P, Hanawa T
    Surf Iinterface anal, 47(13) 1148-1154, Dec, 2015  Peer-reviewed
  • Umezawa T, Chen P, Tsutsumi Y, Doi H, Ashida M, Suzuki S, Moriyama K, Hanawa T
    Dental Materials Journal, 34(5) 713-718, Oct, 2015  
    To confirm similarity of hard tissue compatibility between titanium and zirconium, calcification of MC3T3-E1 cells on titanium and zirconium was evaluated in this study. Mirror-polished titanium (Ti) and zirconium (Zr) disks and zirconium-sputter deposited titanium (Zr/Ti) were employed in this study. The surface of specimens were characterized using scanning electron microscopy and X-ray diffraction. Then, the cellular proliferation, differentiation and calcification of MC3T3-E1 cells on specimens were investigated. The surface of Zr/Ti was much smoother and cleaner than those of Ti and Zr. The proliferation of the cell was the same among three specimens, while the differentiation and calcification on Zr/Ti were faster than those on Ti and Zr. Therefore, Ti and Zr showed the identical hard tissue compatibility according to the evaluation with MC3T3-E1 cells. Sputter deposition may improve cytocompatibility.
  • Ashida M, Sugimoto T, Nomura N, Tsutsumi Y, Chen P, Doi H, Hanawa T
    Mater. Trans., 56(9) 1544-1548, Jul, 2015  Peer-reviewedLead authorCorresponding author
    A large-scale ingot of Zr-1Mo alloy was produced for industrial manufacturing to investigate whether it is possible to produce an ingot with homogeneity. The homogeneous ingot with a chemical composition of Zr-1 mass%Mo was prepared successfully. The microstructure, mechanical properties, and magnetic susceptibility were evaluated. The microstructure showed a coarse colony structure of a plate-like α phase and a thin β phase. An ω phase precipitation was observed in the β phase. Elongation of 23% and magnetic susceptibility of 12.4 × 10−9 m3 kg−1 (0.98 × 10−6 cm3 g−1) were achieved. We found that it is possible to produce a homogeneous large-scale ingot of Zr-1Mo with high elongation and low magnetic susceptibility.
  • Ashida M, Chen P, Doi H, Tsutsumi Y, Hanawa T, Horita Z
    Mater. Sci. Eng. A, 640 449-453, Jun, 2015  Peer-reviewedLead authorCorresponding author
  • Yu M, Chen P, Tsutsumi Y, Doi H, Ashida M, Kasugai S, Hanawa T
    Dent. Mater. J., 33 490-498, Aug, 2014  Peer-reviewed
  • Edalati K, Ashida M, Horita Z, Matsui T, Kato H
    Wear, 310 83-89, Feb, 2014  Peer-reviewed
  • Maki Ashida, Peng Chen, Hisashi Doi, Yusuke Tsutsumi, Takao Hanawa, Zenji Horita
    11TH INTERNATIONAL CONFERENCE ON TECHNOLOGY OF PLASTICITY, ICTP 2014, 81 1523-1528, 2014  Peer-reviewedLead authorCorresponding author
    Ti-6Al-7Nb was deformed by high-pressure torsion to improve the mechanical properties of the alloy. high-pressure torsion was conducted at room temperature under pressures of 2 and 6 GPa for disk-shaped specimens. Microstructure was characterized by transmission electron microscopy (TEM) and X-ray diffraction analysis (XRD). Mechanical properties were evaluated by tensile test and Vickers microhardness measurement. The grain size was refined to about 100 nm after high-pressure torsion processing under 6 GPa through 5 revolutions. Hardness increased with straining by high-pressure torsion and the values after high-pressure torsion processing under 6 GPa were higher than those under 2 GPa. Tensile strength after high-pressure torsion processing of all conditions was higher than that before high-pressure torsion processing. It was found that microstructure and mechanical properties were improved by high-pressure torsion processing. (C) 2014 Published by Elsevier Ltd.
  • Maki Ashida, Zenji Horita
    JOURNAL OF MATERIALS SCIENCE, 47(22) 7821-7827, Nov, 2012  Peer-reviewedLead authorCorresponding author
    Pure Al powders were mixed with a 30 % volume fraction of Al2O3 powders having particle sizes of similar to 30 nm. The mixed powders were first subjected to ball milling (BM) and thereafter consolidated by high-pressure torsion (HPT) at room temperature under a pressure of 3 GPa for 10 turns. The Al-Al2O3 composite produced by BM and HPT (BM + HPT) had a more uniform dispersion of the nano-sized Al2O3 particles in the Al matrix. Hardness values of the BM + HPT composites were higher than those of the composites without BM. It is shown that the use of BM powders for HPT is more effective in achieving a uniform dispersion of the nano-sized Al2O3 particles and in improving mechanical properties of the Al-Al2O3 nanocomposites.

Misc.

 5
  • Yusuke Tsutsumi, Takuya Ishimoto, Kyosuke Ueda, Shinpei Maruyama, Tetsuji Kuse, Aira Matsugaki, Maki Ashida, Peng Chen
    Materia Japan, 59(12) 679-684, Dec 1, 2020  Peer-reviewed
  • Peng Chen, Keisuke Takenaka, Masahiro Tsukamoto, Maki Ashida, Yusuke Tsutsumi, Hisashi Doi, Takao Hanawa
    Transactions of the Annual Meeting of the Society for Biomaterials and the Annual International Biomaterials Symposium, 40 355, 2019  
    Introduction: The next generation surface modification on medical and dental implants is coatings of tissue or stem cells on them.1 To promote cellular attachment and formation of tissues on materials, the control of patterned surface topography is necessary, as the surface topography of a material governs its biocompatibility. For example, in the case of titanium (Ti), nanometer scale topographical features influence cell spreading and micrometer scale topography promotes stem cell differentiation in vitro.2-4 To clarify the role of patterned nano topographies on the biocompatibility and osteoconductivity of metal implant, we investigated the adhesion and calcification of mouse preosteoblast (MC3T3-E1) to Ti surfaces with three surface patterned nano-ripples topography fabricated by single-shot femtosecond laser irradiation.
  • 高市 敦士, 加嶋 祐佳, 中本 貴之, 蘆田 茉希, 土居 壽, 野村 直之, 塙 隆夫, 高橋 英和, 若林 則幸
    日本歯科理工学会誌, 34(5) 326-326, Sep, 2015  
  • Tsutsumi Y, Ashida M, Doi H, Hanawa T
    The journal of the Japanese Society for Dental Materials and Devices, 34(2) 121-121, Mar 25, 2015  
    Micro-arc oxidation (MAO) was performed on a titanium (Ti) to achieve both hard-tissue compatibility and antibacterial property. The surface oxide layer formed on Ti by MAO treatment in a mixture of calcium glycerophosphate, calcium acetate, and silver nitrate was evaluated by surface analyses, cell and microbial testing. Small amount of Ag was incorporated into the porous oxide layer by MAO treatment. Ag-ion release was confirmed during immersion in a physiological saline. The released Ag ions completely inhibit the proliferation of E. coli while the proliferation and mineralization activity of MC3T3-E1 cells was not affected when MAO treatment condition was optimized.
  • 49 3-6, 2015  

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