A Method to Analyze Plantar Stiffness Variation in Diabetes Using Myotonometric Measurements

Abstract Diabetes mellitus is a group of metabolic disease, which has become globally prevalent, and affects a large population in socio-economically backward countries in Asian continent. Chronic diabetes can lead to ulceration in the plantar region and may result in amputation. Assessment of mechanical properties of plantar tissues can aid in early diagnosis of ulceration. Myotonometry, a technique to measure dynamic stiffness, is preferred due to its noninvasiveness, easy employability, and rapid investigation. In this study, an attempt has been made to analyze the changes in biomechanical properties of plantar soft tissue in diabetes. MyotonPro, a handheld device, is used for this purpose. 43 diabetic subjects with varied duration of diabetes are recruited. Site-specific mechanical properties of the plantar region for both the feet are acquired and statistical analysis is performed. Results show that the MyotonPro is able to differentiate the stages of diabetes. It is seen that there is a spatial variability in the mechanical properties of the plantar. Additionally, it is observed that there is a significant increment in the plantar stiffness value in the group with higher diabetic age (p < 0.05). Further, significant changes in dynamic mechanical properties are also observed in submetatarsal region. Additionally, a right–left asymmetry has been observed in frequency and stiffness values for later stages of diabetes. This study demonstrated the feasibility of MyotonPro in discriminating the stages of diabetic period. Thus, the proposed approach could be useful in early diagnosis of foot ulceration for various clinical conditions.

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The dynamic impact behavior of the human neurocranium

Scientific Reports ◽

10.1038/s41598-021-90322-3 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Johann Zwirner ◽

Benjamin Ondruschka ◽

Mario Scholze ◽

Joshua Workman ◽

Ashvin Thambyah ◽

...

Keyword(s):

Mechanical Properties ◽

Bending Strength ◽

Human Head ◽

Biomechanical Properties ◽

Dynamic Mechanical Properties ◽

Sample Thickness ◽

Impact Behavior ◽

Temporal Area ◽

Biomechanical Models ◽

Age Range

AbstractRealistic biomechanical models of the human head should accurately reflect the mechanical properties of all neurocranial bones. Previous studies predominantly focused on static testing setups, males, restricted age ranges and scarcely investigated the temporal area. This given study determined the biomechanical properties of 64 human neurocranial samples (age range of 3 weeks to 94 years) using testing velocities of 2.5, 3.0 and 3.5 m/s in a three-point bending setup. Maximum forces were higher with increasing testing velocities (p ≤ 0.031) but bending strengths only revealed insignificant increases (p ≥ 0.052). The maximum force positively correlated with the sample thickness (p ≤ 0.012 at 2.0 m/s and 3.0 m/s) and bending strength negatively correlated with both age (p ≤ 0.041) and sample thickness (p ≤ 0.036). All parameters were independent of sex (p ≥ 0.120) apart from a higher bending strength of females (p = 0.040) for the 3.5 -m/s group. All parameters were independent of the post mortem interval (p ≥ 0.061). This study provides novel insights into the dynamic mechanical properties of distinct neurocranial bones over an age range spanning almost one century. It is concluded that the former are age-, site- and thickness-dependent, whereas sex dependence needs further investigation.

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Experimental investigation for dynamic stiffness and dimensional accuracy of FDM manufactured part using IV-Optimal response surface design

Rapid Prototyping Journal ◽

10.1108/rpj-10-2015-0137 ◽

2017 ◽

Vol 23 (4) ◽

pp. 736-749 ◽

Cited By ~ 9

Author(s):

Omar Ahmed Mohamed ◽

Syed Hasan Masood ◽

Jahar Lal Bhowmik

Keyword(s):

Mechanical Properties ◽

Mechanical Performance ◽

Dynamic Stiffness ◽

Dimensional Accuracy ◽

Dynamic Mechanical Properties ◽

Operating Parameters ◽

Optimal Process ◽

Content Type ◽

Optimal Response ◽

Dynamic Mechanical

Purpose Fused deposition modeling (FDM) has become an increasingly important process among the available additive manufacturing technologies in various industries. Although there are many advantages of FDM process, a downside of its industrial application is the attainable dimensional accuracy with tight tolerance without compromising the mechanical performance. This paper aims to study the effects of six FDM operating parameters on two conflicting responses, namely, dynamic stiffness and dimensional stability of FDM produced PC-ABS parts. This study also aims to determine the optimal process settings using graphical optimization that satisfy the dynamic mechanical properties without compromising the dimensional accuracy. Design/methodology/approach The regression models based upon IV-optimal response surface methodology are developed to study the variation of dimensional accuracy and dynamic mechanical properties with changes in process parameter settings. Statistical analysis was conducted to establish the relationships between process variables and dimensional accuracy and dynamic stiffness. Analysis of variance is used to define the level of significance of the FDM operating parameters. Scanning electron microscope and Leica MZ6 optical microscope are used to examine and characterize the morphology of the structures for some specimens. Findings Experimental results highlight the individual and interaction effects of processing conditions on the dynamic stiffness and part accuracy. The results showed that layer thickness (slice height), raster-to-raster air gap and number of outlines have the largest effect on the dynamic stiffness and dimensional accuracy. The results also showed an interesting phenomenon of the effect of number of contours and the influence of other process parameters. The optimal process conditions for highest mechanical performance and part accuracy are obtained. Originality/value The effect of FDM processing parameters on the properties under dynamic and cyclic loading conditions has not been studied in the previous published work. Furthermore, simultaneous optimization of dynamic mechanical properties without compromising the dimensional accuracy has also been investigated. On the basis of experimental findings, it is possible to provide practical suggestions to set the optimal FDM process parameters in relation to dynamic mechanical performance, as well as the dimensional accuracy.

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Biomechanical Properties of the Stifle Joint Lateral Collateral Ligament in Dogs

Veterinary and Comparative Orthopaedics and Traumatology ◽

10.1055/s-0038-1633103 ◽

1992 ◽

Vol 05 (04) ◽

pp. 158-162 ◽

Cited By ~ 1

Author(s):

D. Blackketter ◽

J Harari ◽

J. Dupuis

Keyword(s):

Mechanical Properties ◽

Cruciate Ligament ◽

Lateral Collateral Ligament ◽

Biomechanical Properties ◽

Fibular Head ◽

Joint Stability ◽

Collateral Ligament ◽

Cranial Cruciate Ligament ◽

Stifle Joint

Bone/lateral collateral ligament/bone preparations were tested and structural mechanical properties compared to properties of cranial cruciate ligament in 15 dogs. The lateral collateral ligament has sufficient stiffness to provide stifle joint stability and strength to resist acute overload following fibular head transposition.

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