What's New
2016（July－December）
-
2016.12.25
-
2016.12.2
-
2016.11.30
-
2016.11.30
-
2016.11.22
-
2016.11.21
-
2016.11.21
-
2016.11.9
-
2016.11.5
-
2016.11.1
-
2016.10.22
-
2016.9.22
-
2016.9.21
-
2016.8.4
-
2016.7.15
-
2016.7.8
-
2016.12.25
A paper that found that melanoma, a bone-resorbing cancer, disrupts bone orientation and reduces bone mechanical function was published in the Journal of Structural Biology as an open access journal.
Aiko Sekita, Aira Matsugaki, Takuya Ishimoto, Takayoshi Nakano:
Synchronous disruption of anisotropic arrangement of the osteocyte network and collagen/apatite in melanoma bone metastasis,
Journal of Structural Biology, (2016),
DOI: 10.1016/j.jsb.2016.12.003.Abstract
Cancer metastasis to bones increases the risk of fragility fracture by altering bone metabolism and disrupting bone structure. Osteocytes, which organize a dense network that is closely linked with the circumambient matrix, play a key role in regulation of bone microstructure and material properties. The aim of this study was to elucidate the influence of cancer metastasis on the organization of the osteocyte network and collagen/biological apatite (BAp) microstructure in the context of osteocyte/matrix coupling. Using a mouse model intracardially injected with B16F10 melanoma cells or vehicle, the geometric and metabolic changes to osteocytes were analyzed by nano-computed tomography (nano-CT) and histology, and the alignment of collagen fibrils and BAp was analyzed by birefringence measurement and microbeam-X-ray diffraction, respectively. The material properties of bones were further analyzed with nanoindentation method. These experiments revealed that the osteocyte network was markedly disorganized in cancer-bearing bone tissues. The osteocytes showed a variety of residing states in the lacunae; some lacunae were osteolytic while some were replete with immature matrix, suggesting significant disruption in osteocyte/matrix coupling. Collagen/BAp microstructure was also disorganized in cancer-bearing bones as observed by significant decreases in the preferential alignment of both collagen fibrils and BAp; the latter was further shown to be significantly correlated with Young's modulus. The present study revealed that the disruption in the arrangement of the osteocyte network and collagen/BAp microstructure and the deterioration of mechanical function occurred synchronously during cancer bone metastasis.Click here for this paper.
-
2016.12.2
An article on cell control by metal surface shape appeared in the December issue of Matelia.
Aira Matsugaki, Takayoshi Nakano:
Cell Alignment Imaging Based on Materials Engineering Methods,
Special Issue on Frontiers of Microstructure Research for Materials Development by Microscopy (10) - Advances in Microscopic Imaging Techniques and New Developments in Materials Science - (1) Various Imaging Techniques, Matelia, 55 [12], (2016), pp. 579.Click here for this PDF.
-
2016.11.30
Our paper on the contribution of peculiar band structure in TiAl to mechanical properties by layer-by-layer fabrication has gained open access.
M. Todai, T. Nakano, T. Liu, H. Y. Yasuda, K. Hagihara, K. Cho, M. Ueda, M.Takayama:
Effect of building direction on the microstructure and tensile properties of Ti-48Al-2Cr-2Nb alloy additively manufactured by electron beam melting,
Additive Mannufacturing, 13C (2017), pp. 61-70
DOI: http://dx.doi.org/10.1016/j.addma.2016.11.001Abstract
This paper clarified a novel strategy to improve the tensile properties of the Ti-48Al-2Cr-2Nb alloys fabricated by electron beam melting (EBM), via the finding of the development of unique layered microstructure composed of duplex-like fine grains layers and coarser γ grains layers. It was clarified that the mechanical properties of the alloy fabricated by EBM can be controlled by varying an angle θ between EBM-building directions and stress loading direction. At room temperature, the yield strength exhibits high values more than 550 MPa at all the loading orientations investigated (θ = 0, 45 and 90°). In addition, the elongation at θ = 45° was surprisingly larger than 2%, owing to the development of this unique layered microstructure. The anisotropy of the yield strength decreased with increasing temperature. All the examined alloys exhibited a brittle-ductile transition temperature of approximately 750 °C and the yield strength and tensile elongation at 800 °C were over 350 MPa and 40%, respectively.
By the detailed observation of the microstructure, the formation mechanism of the unique layered microstructure was found to be closely related to the repeated local heat treatment effect during the EBM process, and thus its control is further possible by the tuning-up of the process parameters. The results demonstrate that the EBM process enables not only the fabrication of TiAl products with complex shape but also the control of the tensile properties associated with the peculiar microstructure formed during the process.Click here for this paper.
-
2016.11.30
An article about the high-strength, high-entropy alloy with excellent biocompatibility developed in our laboratory was published in the Nikkan Kogyo Shimbun.
Click here for this article.
-
2016.11.22
The world's first paper on the modeling of heat-resistant MoSi₂ and the fabrication of <001]-fiber textures has gained open access.
Koji Hagihara, Takayoshi Nakano*, Masahiro Suzuki, Takuya Ishimoto, Su yalatu, Shi-Hai Sun:
Successful additive manufacturing of MoSi2 including crystallographic texture and shape control,
Journal of Alloys and Compounds (JALCOM), 696, (2017), pp.67–72
DOI: 10.1016/j.jallcom.2016.11.191Abstract
MoSi2 is one of the promising candidates for ultrahigh-temperature structural materials. However, its product fabrication has been limited owing to its significant brittleness until now. As an approach to overcome this, we have first successfully fabricated MoSi2 samples via additive manufacturing (AM). Control of the thermal expansion coefficient of the start plate for AM is important for building a three-dimensional MoSi2 product with a low deformability. Moreover, unidirectional laser scanning is found to be significantly effective for controlling the crystallographic texture in MoSi2 with a low crystal symmetry. By the unidirectional scanning, [001] texture could be developed along the scanning direction, which possibly results in the fabrication of the MoSi2 products with better high-temperature strength.
Click here for this paper.
-
2016.11.21
Dr. Nakano received the Award of Japanese Society for Biomaterials (in science field) at the Japanese Society for Biomaterials Symposium 2016.
Dr. Nakano received the Award of Japanese Society for Biomaterials(in science field) and gave the award lecture.
-
2016.11.21
The paper on dental implants considering bone orientation, which we have been working on in collaboration with Nagasaki University, is now open access.
Shinichiro Kuroshima, Takayoshi Nakano, Takuya Ishimoto, Muneteru Sasaki, Maaya Inoue, Munenori Yasutake, Takeshi Sawase:
Optimally oriented grooves on dental implants improve bone quality around implants under repetitive mechanical loading,
Acta Biomaterialia, 48, 15, 2017, pp433-444.Abstract
The aim was to investigate the effect of groove designs on bone quality under controlled-repetitive load conditions for optimizing dental implant design. Anodized Ti-6Al-4V alloy implants with −60° and +60° grooves around the neck were placed in the proximal tibial metaphysis of rabbits. The application of a repetitive mechanical load was initiated via the implants (50 N, 3 Hz, 1800 cycles, 2 days/week) at 12 weeks after surgery for 8 weeks. Bone quality, defined as osteocyte density and degree of biological apatite (BAp) c-axis/collagen fibers, was then evaluated. Groove designs did not affect bone quality without mechanical loading; however, repetitive mechanical loading significantly increased bone-to-implant contact, bone mass, and bone mineral density (BMD). In +60° grooves, the BAp c-axis/collagen fibers preferentially aligned along the groove direction with mechanical loading. Moreover, osteocyte density was significantly higher both inside and in the adjacent region of the +60° grooves, but not −60° grooves. These results suggest that the +60° grooves successfully transmitted the load to the bone tissues surrounding implants through the grooves. An optimally oriented groove structure on the implant surface was shown to be a promising way for achieving bone tissue with appropriate bone quality. This is the first report to propose the optimal design of grooves on the necks of dental implants for improving bone quality parameters as well as BMD. The findings suggest that not only BMD, but also bone quality, could be a useful clinical parameter in implant dentistry.Statement of Significance
Although the paradigm of bone quality has shifted from density-based assessments to structural evaluations of bone, clarifying bone quality based on structural bone evaluations remains challenging in implant dentistry. In this study, we firstly demonstrated that the optimal design of dental implant necks improved bone quality defined as osteocytes and the preferential alignment degree of biological apatite c-axis/collagen fibers using light microscopy, polarized light microscopy, and a microbeam X-ray diffractometer system, after application of controlled mechanical load. Our new findings suggest that bone quality around dental implants could become a new clinical parameter as well as bone mineral density in order to completely account for bone strength in implant dentistry.Click here for this paper.
-
2016.11.9
Our paper on high-entropy alloys has been accepted for publication in "scripta Materialia" and will be open access on November 9.
Mitsuharu Todai, Takeshi Nagase, Takao Hori, Aira Matsugaki, Aiko Sekita, Takayoshi Nakano:
Novel TiNbTaZrMo high-entropy alloys for metallic biomaterials,
Scripta Materialia, 129C, (2017), pp.65–68
DOI: 10.1016/j.scriptamat.2016.10.028Click here for this paper.
-
2016.11.5
Ms. Liu (M2) won the Best Poster Award at the 131st Japan Institute of Light Metals.
Liu Tianqi, Mitsuharu Todai, Hiroyuki Yasuda, Ken Zhao, Koji Hagiwara, Takayoshi Nakano, Ayako Ikeda, Daisuke Kondo:
Introduction of Specific Layered Microstructure by Electron Beam Additive Manufacturing and Development of High Ductility Ti-48Al-2Cr-2Nb Alloy Using the Microstructure -
2016.11.1
An article about our laboratory's research was published in the November issue of Monthly Municipal Solutions (pages 69-71).
This article, "New findings on bone function recovery at Osaka University," was written by Takeshi Hayashi of the Nikkan Kogyo Shimbun and introduces Nakano Lab's research.
Click here for more details.
-
2016.10.22
The results of our laboratory's research on reduced bone matrix orientation under no load were published in Carcified Tissue International (CTIN).
Jun Wang, Takuya Ishimoto and Takayoshi Nakano:
Unloading-induced degradation of the anisotropic arrangement of collagen/apatite in rat femurs,
Carcified Tissue International (CTIN), (2016) in press.
DOI:10.1007/s00223-016-0200-0Abstract
The specific orientation of collagen and biological apatite (BAp) is an anisotropic feature of bone micro-organization; it is an important determinant of bone mechanical function and performance under anisotropic stress. However, it is poorly understood how this microstructure orientation is altered when the mechanical environment changes. We hypothesized that the preferential orientation of collagen/BAp would change in response to changes in mechanical conditions, similar to the manner in which bone mass and bone shape change. In the present study, we investigated the effect of unloading (removal of anisotropic stress) on the preferential orientation of collagen/BAp using a rat sciatic neurectomy model. Bone tissue that formed under unloaded conditions showed a more disordered collagen/BAp orientation than bone tissue that formed under physiological conditions. Coincidentally, osteocytes in unloaded bone displayed spherical morphology and random alignment. To the best of our knowledge, this study is the first to demonstrate the degradation of preferential collagen/BAp orientation in response to unloading conditions. In summary, we identified alterations in bone material anisotropy as an important aspect of the bone’s response to unloading, which had previously been examined with regard to bone loss only.Click here for this paper.
-
2016.9.22
Mr. Yamazaki (M1) and our lab's presentation won The 159th Japan Institute of Metals and Materials The Metals Best Poster Award.
〇Daisuke Yamazaki, Ryosuke Kozasa, Aya Matsugaki, Takayoshi Nakano:
Construction of in vivo similar anisotropic vascular structuresTakao Hori, LIU TIANQI, Masahiro Suzuki, Kenta Hisamoto:
One-of-a-kind custom lights by metal 3D printer,
The 159th Japan Institute of Metals and Materials World Materials Day Award〇Jisun Lee, Koji Hagiwara, Takayoshi Nakano, Michiaki Yamazaki, Yoshihito Kawamura:
Composition, temperature and strain rate dependence of plastic behavior of Mg-based LPSO phase〇Kentaro Ishii, Koji Hagiwara, and Takayoshi Nakano.
Correlation between microstructure and dissolution behavior of Ca-Mg-Zn-based soluble multi-phase alloys -
2016.9.21
At the 159th Annual Meeting of the Japan Institute of Metals, Dr. Todai received The 26th Japan Institute of Metals and Materials Young Researcher Award, and Dr. Ikeo (currently an assistant professor at Kobe University) received The 64th Japan Institute
○Mitsuharu Todai:
Development of Structural Materials for Biomedical Applications from the Viewpoint of Materials Physics○Naoko Ikeo, Takuya Ishimoto, Natsumi Hiramoto, Hidetsugu Fukuda, Hiroyuki Ogisu, Yutaro Araki, Takayoshi Nakano:
Solid/Powder Clad Ti-6Al-4V Alloy with Low young’s Modulus and High Toughness fabricated by Electron Beam Melting,
Materials Transaction, Vol.56, No.5 -
2016.8.4
Mr. Inagaki won the Excellent Poster Award for Young Scientist at PRICM9.
Y. Inagaki, R. Ozasa, A. Matsugaki, T. Nakano:
Osteoblast Arrangement Controlled by Interaction with Osteoclast -
2016.7.15
Our lab's paper on TNTZ has been published in the journal "Scientific Reports" published by nature.
Koji Hagihara, Takayoshi Nakano, Hideaki Maki, Yukichi Umakoshi, Mitsuo Niinomi:
Isotropic plasticity of β-type Ti-29Nb-13Ta-4.6Zr alloy single crystals for the development ofsingle crystalline β-Ti implants
Scientific Reports, 6, 20779, (2016)
DOI: 10.1038/srep29779Abstract
β-type Ti-29Nb-13Ta-4.6Zr alloy is a promising novel material for biomedical applications. We have proposed a 'single crystalline β-Ti implant' as new hard tissue replacements for suppressing the stress shielding by achieving a drastic reduction in the Young's modulus. To develop this, the orientation dependence of the plastic deformation behavior of the Ti-29Nb-13Ta-4.6Zr single crystal was first clarified. Dislocation slip with a Burgers vector parallel to <111> was the predominant deformation mode in the wide loading orientation. The orientation dependence of the yield stress due to <111> dislocations was small, in contrast to other β-Ti alloys. In addition, {332} twin was found to be operative at the loading orientation around [001]. The asymmetric features of the {332} twin formation depending on the loading orientation could be roughly anticipated by their Schmid factors. However, the critical resolved shear stress for the {332} twins appeared to show orientation dependence. The simultaneous operation of <111> slip and {332} twin were found to be the origin of the good mechanical properties with excellent strength and ductility. It was clarified that the Ti-29Nb-13Ta-4.6Zr alloy single crystal shows the "plastically almost-isotropic and elastically highly-anisotropic" nature, that is desirable for the development of 'single crystalline β-Ti implant' -
2016.7.8
Our paper on anomalous strengthening mechanism using CoCr single crystal has been published in "Scripta Materialia".
Koji Hagihara, Takayoshi Nakano, Keita Sasaki:
Anomalous strengthening behavior of Co-Cr-Mo alloy single crystals for biomedical application,
Scripta Materialia, 123 (2016), pp.149-153
DOI: 10.1016/j.scriptamat.2016.06.016Abstract
This is the first repot on the deformation behavior of Co-Cr-Mo biomedical alloy single crystals predominantly having an fcc structure. In the single crystal, one of four ε-variants was selectively formed, and its geometry was found to drastically affect the mechanical properties. The yield stress in the [111] orientation, in which the formation of ε-phase strain-induced martensite (SIM) crosses the grown-in ε-variant, was more than six times larger than that in the [149] orientation, where SIM was formed parallel to the grown-in ε-variant. The intersection mechanism of the ε-variants is discussed via observations of the deformation microstructure.