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You searched for subject:(lmhf). Showing records 1 – 2 of 2 total matches.

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Michigan Technological University

1. Nelson, Brad. A Smart Implantable Bone Fixation Plate Providing Actuation and Load Monitoring for Orthopedic Fracture Healing.

Degree: PhD, Department of Biomedical Engineering, 2019, Michigan Technological University

Fracture non-union occurs in roughly 5-10% of all fracture cases, and current interventions are both time-consuming and costly. There is therefore significant incentive to develop new tools to improve fracture healing outcomes. Several studies have shown that low-magnitude, high-frequency (LMHF) mechanical loading can promote faster healing and reduce the risk of refracture in critical-size long bone fractures. This is typically done using whole-body vibration, which may result in undesirable systemic effects on the rest of the body. This work discusses an implantable piezoelectric fixation plate that can both apply LMHF loading directly to the fracture site using flexible scheduling and indirectly monitor the progress of healing by using the increasing stiffness of the fracture callus. The design and performance of the piezoelectric bone plate show that the device can apply the target treatment and has the sensitivity to be used to observe the progress of healing. An accompanying telemetry system using BLE communication is also introduced which has a footprint of suitable size to be used in rodent studies and can provide the power necessary for piezoelectric actuation. These results pave the way for future studies regarding the efficacy and optimization of LMHF treatments in fracture healing models. Advisors/Committee Members: Keat Ghee Ong.

Subjects/Keywords: Fracture healing; fixation plate; lmhf; piezoelectric; Biomedical Devices and Instrumentation

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Nelson, B. (2019). A Smart Implantable Bone Fixation Plate Providing Actuation and Load Monitoring for Orthopedic Fracture Healing. (Doctoral Dissertation). Michigan Technological University. Retrieved from https://digitalcommons.mtu.edu/etdr/898

Chicago Manual of Style (16th Edition):

Nelson, Brad. “A Smart Implantable Bone Fixation Plate Providing Actuation and Load Monitoring for Orthopedic Fracture Healing.” 2019. Doctoral Dissertation, Michigan Technological University. Accessed December 04, 2020. https://digitalcommons.mtu.edu/etdr/898.

MLA Handbook (7th Edition):

Nelson, Brad. “A Smart Implantable Bone Fixation Plate Providing Actuation and Load Monitoring for Orthopedic Fracture Healing.” 2019. Web. 04 Dec 2020.

Vancouver:

Nelson B. A Smart Implantable Bone Fixation Plate Providing Actuation and Load Monitoring for Orthopedic Fracture Healing. [Internet] [Doctoral dissertation]. Michigan Technological University; 2019. [cited 2020 Dec 04]. Available from: https://digitalcommons.mtu.edu/etdr/898.

Council of Science Editors:

Nelson B. A Smart Implantable Bone Fixation Plate Providing Actuation and Load Monitoring for Orthopedic Fracture Healing. [Doctoral Dissertation]. Michigan Technological University; 2019. Available from: https://digitalcommons.mtu.edu/etdr/898

2. Birmingham, Evelyn. The mechanical environment of the stem cell niche in bone marrow .

Degree: 2014, National University of Ireland – Galway

Understanding how bone marrow mesenchymal stem cells (MSCs) contribute to new bone formation and remodelling in vivo is of principal importance for informing the development of effective bone tissue engineering strategies in vitro. However, the precise stimuli for osteogenic differentiation of MSCs in vivo have not been fully established. The work presented in this thesis uses a combination of experimental and computational modelling approaches to investigate the in vivo environment of the stem cell niche in bone marrow, with a specific goal of identifying important biochemical and mechanical cues for osteogenic differentiation of MSCs. Support cells within the niche are examined for their roles in osteogenic differentiation. Specifically osteocytes and osteoblasts are examined due to their established role as regulatory cells in bone. Osteocytes are found to be more dominant than osteoblasts. However, when cultured together, a synergistic relationship is found to exist between them, for stimulating the osteogenic differentiation of MSCs. Fluid structure interaction (FSI) models are used to determine whether MSCs can be directly stimulated by mechanical cues within the bone marrow. Models predict that the shear stress generated due to physiological loading is within the stimulatory range (maximum values range from 0.025 - 0.25 Pa). Additionally, it is found that the onset of osteoporosis can alter the shear stress within the marrow. Explanted samples of trabecular bone and marrow are physiologically compressed and are found to have greater osteogenic activity, as verified by bone histomorphometry, compared to static samples. FSI models demonstrate that bone strain, not marrow shear stress, is likely the driving mechanical signal during compression. To focus on shear stress in the marrow, low-magnitude high-frequency vibration loading is used as this induces minimal bone strain while generating marrow shear stress. ยต-CT analysis shows strong bone formation and remodelling in vibration samples compared to static samples. Computational models reveal a significant relationship between this formation and remodelling and shear stress in the marrow. Together the results of this PhD thesis demonstrate that: (1) osteocytes and osteoblasts can stimulate osteogenic differentiation of MSCs. (2) Shear stress of sufficient magnitude to stimulate the osteogenic differentiation of MSCs, is generated during compression, but this can be altered in osteoporotic bone. (3) In vivo responses of bone to compression loading are replicated in explanted samples; however, models indicate that bone strain is the dominant signal. Finally, (4) explanted samples exposed to vibrational loading experience more marrow shear stress than in compression loading, and the magnitude of the shear stress has a causal role in the formation of bone and improvement in bone architecture parameters. Advisors/Committee Members: McHugh, Peter (advisor).

Subjects/Keywords: Bone; Bone marrow; MSCs; Stem cell niche; Biomechanics; FE; CFD; FSI; LMHF; Biomedical Engineering

…formation in areas of high shear stress within the marrow Low-magnitude high-frequency (LMHF… …Introduction response remains unknown. The bone strain induced under LMHF is minimal compared to… …that LMHF loading generates significant shear stress within the marrow (Coughlin and… …Niebur, 2012; Dickerson et al., 2008). Additionally, LMHF vibration has been shown to be… …et al., 2008). It is proposed that LMHF vibration generates a mechanical signal within… 

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Birmingham, E. (2014). The mechanical environment of the stem cell niche in bone marrow . (Thesis). National University of Ireland – Galway. Retrieved from http://hdl.handle.net/10379/4422

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Birmingham, Evelyn. “The mechanical environment of the stem cell niche in bone marrow .” 2014. Thesis, National University of Ireland – Galway. Accessed December 04, 2020. http://hdl.handle.net/10379/4422.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Birmingham, Evelyn. “The mechanical environment of the stem cell niche in bone marrow .” 2014. Web. 04 Dec 2020.

Vancouver:

Birmingham E. The mechanical environment of the stem cell niche in bone marrow . [Internet] [Thesis]. National University of Ireland – Galway; 2014. [cited 2020 Dec 04]. Available from: http://hdl.handle.net/10379/4422.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Birmingham E. The mechanical environment of the stem cell niche in bone marrow . [Thesis]. National University of Ireland – Galway; 2014. Available from: http://hdl.handle.net/10379/4422

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

.