Browsing by Subject "Strength"

Now showing 1 - 5 of 5
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    Effects of Raloxifene and tibial loading on bone mass and mechanics in male and female mice
    (Taylor & Francis, 2022) Berman, Alycia G.; Damrath, John G.; Hatch, Jennifer; Pulliam, Alexis N.; Powell, Katherine M.; Hinton, Madicyn; Wallace, Joseph M.; Biomedical Engineering, School of Engineering and Technology
    Raloxifene (RAL) is a selective estrogen receptor modulator (SERM) that has previously been shown to cause acellular benefits to bone tissue. Due to these improvements, RAL was combined with targeted tibial loading to assess if RAL treatment during periods of active bone formation would allow for further mechanical enhancements. To do so, structural, mechanical, and microstructural effects were assessed in bone from C57BL/6 mice that were treated with RAL (0.5 mg/kg), tibial loading, or both for 6 weeks, beginning at 10 weeks of age. Ex vivo microcomputed tomography (CT) images indicated RAL and loading work together to improve bone mass and architecture, especially within the cancellous region of males. Increases in cancellous bone volume fraction were heavily driven by increases in trabecular thickness, though there were some effects on trabecular spacing and number. In the cortical regions, RAL and loading both increased cross-sectional area, cortical area, and cortical thickness. Whole-bone mechanical testing primarily indicated effects of loading. Further characterization through Raman spectroscopy and nanoindentation showed load-based changes in mineralization and micromechanics, while both loading and RAL caused changes in the secondary collagen structure. In contrast to males, in females, there were large load-based effects in the cancellous and cortical regions, resulting in increased whole-bone mechanical properties. RAL had less of an effect on cancellous and cortical architecture, though some effects were still present. In conclusion, RAL and loading work together to impact bone architecture and mechanical integrity, leading to greater improvements than either treatment individually.
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    Marginal Fit, Mechanical Properties, and Esthetic Outcomes of CAD/CAM Interim Fixed Dental Prostheses (FDPs): A Systematic Review
    (MDPI, 2023-02-28) Al-humood, Hussain; Alfaraj, Amal; Yang, Chao-Chieh; Levon, John; Chu, Tien-Min Gabriel; Lin, Wei-Shao; Prosthodontics, School of Dentistry
    This systematic review aimed to study the outcomes of CAD-CAM (milled and 3D-printed) interim dental prostheses when compared to conventional ones. The focused question of "In natural teeth, what are the outcomes of CAD-CAM interim FDPs compared to the conventionally-manufactured ones regarding marginal fit, mechanical properties, esthetics, and color stability" was formulated. The systematic search was conducted electronically in the PubMed/MEDLINE, CENTRAL, EMBASE, Web of Science, New York Academy of Medicine Grey Literature Report, and Google Scholar databases by using the MeSH keywords and keywords associated with the focused question and limiting articles to those published between 2000 and 2022. A manual search was conducted in selected dental journals. The results were analyzed qualitatively and are presented in table format. Of the included studies, 18 studies were in vitro and 1 was a randomized clinical trial. Of the eight studies analyzing the mechanical properties, five studies favored the milled interim restorations, one study favored both 3D-printed and milled interim restorations, and two studies reported better mechanical properties in conventional interim restorations. Among four studies evaluating the marginal discrepancies, two studies favored the marginal fit in milled interim restorations, one study reported a better marginal fit in both milled and 3D-printed interim restorations, and one study found conventional interim restorations have a better marginal fit and smaller marginal discrepancy when compared to both milled and 3D-printed restorations. Among five studies that evaluated both the mechanical properties and marginal fit, 1 study favored 3D-printed interim restorations and four studies favored milled interim restorations over the conventional ones. Two studies analyzing the esthetics outcomes demonstrated better results with milled interim restorations compared to conventional and 3D-printed interim restorations in terms of their color stabilities. The risk of bias was low for all the studies reviewed. The high level of heterogeneity within the studies excluded meta-analysis. Most of the studies favored the milled interim restorations over the 3D-printed and conventional restorations. The results suggested that milled interim restorations offer a better marginal fit, higher mechanical properties, and better esthetic outcomes in terms of color stabilities.
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    Musculoskeletal Health Worsened from Carnitine Supplementation and Not Impacted by a Novel Individualized Treadmill Training Protocol
    (Karger, 2024) Troutman, Ashley D.; Srinivasan, Shruthi; Metzger, Corinne E.; Fallen, Paul B.; Chen, Neal; O’Neill, Kalisha D.; Allen, Matthew R.; Biruete, Annabel; Moe, Sharon M.; Avin, Keith G.; Physical Therapy, School of Health and Human Sciences
    Introduction: Chronic kidney disease (CKD) negatively affects musculoskeletal health, leading to reduced mobility, and quality of life. In healthy populations, carnitine supplementation and aerobic exercise have been reported to improve musculoskeletal health. However, there are inconclusive results regarding their effectiveness and safety in CKD. We hypothesized that carnitine supplementation and individualized treadmill exercise would improve musculoskeletal health in CKD. Methods: We used a spontaneously progressive CKD rat model (Cy/+ rat) (n = 11-12/gr): (1) Cy/+ (CKD-Ctrl), (2) CKD-carnitine (CKD-Carn), and (3) CKD-treadmill (CKD-TM). Carnitine (250 mg/kg) was injected daily for 10 weeks. Rats in the treadmill group ran 4 days/week on a 5° incline for 10 weeks progressing from 30 min/day for week one to 40 min/day for week two to 50 min/day for the remaining 8 weeks. At 32 weeks of age, we assessed overall cardiopulmonary fitness, muscle function, bone histology and architecture, and kidney function. Data were analyzed by one-way ANOVA with Tukey's multiple comparisons tests. Results: Moderate to severe CKD was confirmed by biochemistries for blood urea nitrogen (mean 43 ± 5 mg/dL CKD-Ctrl), phosphorus (mean 8 ± 1 mg/dL CKD-Ctrl), parathyroid hormone (PTH; mean 625 ± 185 pg/mL CKD-Ctrl), and serum creatinine (mean 1.1 ± 0.2 mg/mL CKD-Ctrl). Carnitine worsened phosphorous (mean 11 ± 3 mg/dL CKD-Carn; p < 0.0001), PTH (mean 1,738 ± 1,233 pg/mL CKD-Carn; p < 0.0001), creatinine (mean 1 ± 0.3 mg/dL CKD-Carn; p < 0.0001), cortical bone thickness (mean 0.5 ± 0.1 mm CKD-Ctrl, 0.4 ± 0.1 mm CKD-Carn; p < 0.05). Treadmill running significantly improves maximal aerobic capacity when compared to CKD-Ctrl (mean 14 ± 2 min CKD-TM, 10 ± 2 min CKD-Ctrl; p < 0.01). Conclusion: Carnitine supplementation worsened CKD progression, mineral metabolism biochemistries, and cortical porosity and did not have an impact on physical function. Individualized treadmill running improved maximal aerobic capacity but did not have an impact on CKD progression or bone properties. Future studies should seek to better understand carnitine doses in conditions of compromised renal function to prevent toxicity which may result from elevated carnitine levels and to optimize exercise prescriptions for musculoskeletal health.
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    Sex and External Size Specific Limitations in Assessing Bone Health From Adult Hand Radiographs
    (Wiley, 2022-06-29) Bigelow, Erin M.R.; Goulet, Robert W.; Ciarelli, Antonio; Schlecht, Stephen H.; Kohn, David H.; Bredbenner, Todd L.; Harlow, Sioban D.; Karvonen-Gutierrez, Carrie A.; Jepsen, Karl J.; Orthopaedic Surgery, School of Medicine
    Morphological parameters measured for the second metacarpal from hand radiographs are used clinically for assessing bone health during growth and aging. Understanding how these morphological parameters relate to metacarpal strength and strength at other anatomical sites is critical for providing informed decision-making regarding treatment strategies and effectiveness. The goals of this study were to evaluate the extent to which 11 morphological parameters, nine of which were measured from hand radiographs, relate to experimentally measured whole-bone strength assessed at multiple anatomical sites and to test whether these associations differed between men and women. Bone morphology and strength were assessed for the second and third metacarpals, radial diaphysis, femoral diaphysis, and proximal femur for 28 white male donors (18-89 years old) and 35 white female donors (36-89+ years old). The only morphological parameter to show a significant correlation with strength without a sex-specific effect was cortical area. Dimensionless morphological parameters derived from hand radiographs correlated significantly with strength for females, but few did for males. Males and females showed a significant association between the circularity of the metacarpal cross-section and the outer width measured in the mediolateral direction. This cross-sectional shape variation contributed to systematic bias in estimating strength using cortical area and assuming a circular cross-section. This was confirmed by the observation that use of elliptical formulas reduced the systematic bias associated with using circular approximations for morphology. Thus, cortical area was the best predictor of strength without a sex-specific difference in the correlation but was not without limitations owing to out-of-plane shape variations. The dependence of cross-sectional shape on the outer bone width measured from a hand radiograph may provide a way to further improve bone health assessments and informed decision making for optimizing strength-building and fracture-prevention treatment strategies.
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    Towards commercialization of self-healing technology in epoxy coating
    (2014) Ye, Lujie; Jones, Alan S.; Zhang, Jing; Zhu, Likun; Chen, Jie
    This work is focused on developing viable self-healing coatings, especially considering the viability of the coating in a commercial context. With this in mind, finding low cost healing agents, with satisfactory healing and mechanical properties as well as adapting the healing system for use in coatings was required. Seven potential healing agents were evaluated and an air-drying triglyceride (linseed oil) was identified as the candidate healing agent. Different encapsulation techniques were evaluated and ureaformaldehyde microcapsules were chosen as the candidate encapsulation technique. Self-healing coatings were fabricated using urea-formaldehyde encapsulated linseed oil. EIS, SEM and TGA technologies were used to evaluate mechanical performance, corrosion resistance, and self-healing performance.