Bone tissue engineering has been continuously developing since the concept of “tissue engineering” has been proposed. Biomaterials that are used as the basic material for the fabrication of scaffolds play a vital role in bone tissue engineering. This paper first introduces a strategy for literature search. Then, it describes the structure, mechanical properties and materials of natural bone and the strategies of bone tissue engineering. Particularly, it focuses on the current knowledge about biomaterials used in the fabrication of bone tissue engineering scaffolds, which includes the history, types, properties and applications of biomaterials. The effects of additives such as signaling molecules, stem cells, and functional materials on the performance of the scaffolds are also discussed.

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Biomaterials for bone tissue engineering scaffolds: a review

https://onlinelibrary.wiley.com/doi/pdf/10.1002/nme.1620300710

Computer aided kinematics and dynamics of mechanical systems, by E. J. Haug, Allyn and Bacon, Boston, 1989. No. of pages: 511. Price: £47.10 (hardback), ISBN 0-205-11669-8; £18.95 (international student edition), ISBN 0-205-12097-0

Injectable PLGA microspheres with tunable magnesium ion release for promoting bone regeneration

Magnesium-based biomaterials as emerging agents for bone repair and regeneration: from mechanism to application

Bone is a unique tissue that is capable of repairing itself after damage. However, there are certain instances of fractures and defects that require clinical intervention for proper alignment and healing. As with any implant, careful consideration of the material used to create the implants to treat these problems is needed. If the incorrect material is chosen, the implants themselves can lead to bone fractures or defects, or bone healing may not take place at all. All three classes of biomaterials–metals, ceramics, and polymers–have been used in the treatment of both bone fractures and bone defects, and each has its own unique benefits and limitations for its applications. Furthermore, composites of these different materials have also been created to try to take advantage of all the different benefits offered by each different material. This review highlights different materials that have been used for the development of internal fixators and bone graft substitutes to treat fracture and bone defects as well as their limitations and needed future research.

Orthopedic implants and devices for bone fractures and defects: Past, present and perspective

Dynamic instability, that is, resonance, may occur on an electromagnetic suspension-type Maglev that runs over the elevated guideway, particularly at very low speeds, due to the flexibility of the guideway. An analysis of the dynamic interaction between the vehicle and guideway is required at the design stage to investigate such instability, setting slender guideway in design direction for reducing construction costs. In addition, it is essential to design an effective control algorithm to solve the problem of instability. In this article, a more detailed model for the dynamic interaction of vehicle/guideway is proposed. The proposed model incorporates a 3D full vehicle model based on virtual prototyping, flexible guideway by a modal superposition method and levitation electromagnets including feedback controller into an integrated model. By applying the proposed model to an urban Maglev vehicle newly developed for commercial application, an analysis of the instability phenomenon and an investigation of a...

Coupled vibration analysis of Maglev vehicle-guideway while standing still or moving at low speeds

Magnesium (Mg) ions are the most abundant intracellular divalent cations and play a pivotal role in numerous cellular processes. Biodegradable Mg-containing materials, including scaffolds, are promising candidates for orthopedic applications. Here, we investigated the effect of Mg ions on the cellular properties of osteoblasts. Cytotoxicity tests on osteoblasts confirmed that no cytotoxic effects were found up to a supplementing Mg ion concentration of 10 mM. Mg ions at a concentration of 5 mM increased the migration and invasiveness of osteoblasts. To investigate the stimulatory effect of Mg ions on cell motility in scaffolds, we fabricated 10 wt% Mg ion-containing polycaprolactone (PCL) scaffolds, using the wire-network molding (WNM) technique. Mg ion-containing scaffolds persistently released Mg ions at a concentration of 5 mM in the media after pre-incubation. Furthermore, increased cell motility was confirmed in Mg ion-containing scaffolds by quantification of genomic DNA and protein content. Our results provide an important basis for the function of Mg ions and their effect on cell motility, and propose a novel role for Mg ions in scaffold applications.

Magnesium ions enhance infiltration of osteoblasts in scaffolds via increasing cell motility.

Normally, Maglev (magnetic levitation) vehicles run on elevated guideways. The elevated guideway must satisfy various load conditions of the vehicle, and has to be designed to ensure ride quality, while ensuring that the levitation stability of the vehicle is not affected by the deflection of the guideway. However, because the elevated guideways of Maglev vehicles in South Korea and other countries fabricated so far have been based on over-conservative design criteria, the size of the structures has increased. Further, from the cost perspective, they are unfavourable when compared with other light rail transits such as monorail, rubber wheel, and steel wheel automatic guided transit. Therefore, a slender guideway that does have an adverse effect on the levitation stability of the vehicle is required through optimisation of design criteria. In this study, to predict the effect of various design parameters of the guideway on the dynamic behaviour of the vehicle, simulations were carried out using a ...

Design and Validation of a Slender Guideway for Maglev Vehicle by Simulation and Experiment

In this paper, the dynamic performance evaluation of a 5-degree of freedom (DOF) magnetic levitation and guidance device is addressed. In particular, the electromagnetic forces from an equivalent magnetic circuit model are coupled to a 5-DOF dynamic motion model of the device. With the proposed model, dynamic behaviors are simulated by considering the dynamic interactions between levitation and guidance elements while both systems are operating. In addition, the experimental system is successfully tested and stable levitation and guidance is demonstrated at the desired operating gap and unexpected disturbance forces.

Dynamic Performance Evaluation of 5-DOF Magnetic Levitation and Guidance Device by Using Equivalent Magnetic Circuit Model

With the emergence of high-integration array and large area panel process, the need to minimize the generation of particles in the field of semiconductor, LCD and OLED has grown. As an alternative to the conventional roller system, a contactless magnetic conveyor has been proposed to reduce the generation of particles. An EM-PM hybrid which is one of magnetic levitation types is already proposed for the conveyor system. One of problems pointed out with this approach is the vibration caused by the dynamic interaction between conveyor and rail. To reduce the vibration, the introduction of a secondary suspension system which aims to decouple the levitation electromagnet from the main body is proposed. The objective of this study is to develop a dynamic model for the magnetically levitated conveyor, and to investigate the effect of the introduced suspension system. An integrated model of levitation system and rail based on 3D multibody dynamic model is proposed. With the proposed model, the dynamic characteristics of maglev conveyor system are analyzed, and the effect of the secondary suspension and the stiffness and damping are investigated.

Ki-Jung Kim

Papers

Coupled vibration analysis of Maglev vehicle-guideway while standing still or moving at low speeds

Magnesium ions enhance infiltration of osteoblasts in scaffolds via increasing cell motility.

Design and Validation of a Slender Guideway for Maglev Vehicle by Simulation and Experiment

Dynamic Performance Evaluation of 5-DOF Magnetic Levitation and Guidance Device by Using Equivalent Magnetic Circuit Model

Dynamic Analysis of a Maglev Conveyor Using an EM-PM Hybrid Magnet