Aging effects on compressive energy dissipation of cortical bone

Bone fracture has imposed a significant burden on the health of society. The “bone quality” is used to refer to factors affecting bone fracture risk [1]. Energy dissipation till fracture, known as toughness, is a major measure of bone quality [2]. However, underlying mechanisms of energy dissipation in bone is still not clear. It has been well documented that the post-yield behavior of bone determines the major part of the toughness of bone [3, 4]. Therefore, it is important to study post-yield behaviors of human bone, especially the different pathways for energy dissipation, in order to better understand how age-related change affects bone quality. Bone behaves differently under different loading modes [5]. Different from loading in tension, after reaching the maximum stress, cortical bone in compression can continue to bear load till large deformation without brittle failure and dramatic reduction in elastic modulus [5, 6]. However, few studies of progression of post-yield behaviors of cortical bone in compression were reported in the literature.

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Age-related factors affecting the postyield energy dissipation of human cortical bone

Journal of Orthopaedic Research® ◽

10.1002/jor.20337 ◽

2007 ◽

Vol 25 (5) ◽

pp. 646-655 ◽

Cited By ~ 86

Author(s):

Jeffry S. Nyman ◽

Anuradha Roy ◽

Jerrod H. Tyler ◽

Rae L. Acuna ◽

Heather J. Gayle ◽

...

Keyword(s):

Energy Dissipation ◽

Cortical Bone ◽

Related Factors ◽

Factors Affecting ◽

Human Cortical Bone ◽

Age Related

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Progressive Post-Yield Behavior of Human Cortical Bone in Shear

ASME 2011 Summer Bioengineering Conference, Parts A and B ◽

10.1115/sbc2011-53677 ◽

2011 ◽

Cited By ~ 1

Author(s):

Xuanliang Neil Dong ◽

Qing Luo ◽

Bijay Giri ◽

Xiaodu Wang

Keyword(s):

Energy Dissipation ◽

Cortical Bone ◽

Bone Fragility ◽

Stress Fields ◽

Yield Behavior ◽

Test Region ◽

Loading Modes ◽

Iosipescu Test ◽

Progressive Loading ◽

Loading Scheme

Post-yield behavior is important for bone fragility since it accounts for the major part of energy dissipation of bone. Therefore, it is essential to study the post-yield behavior of bone to understand the different pathways for energy dissipation [1]. The post-yield behavior of bone may depend on the different loading modes. Previous studies have utilized a novel progressive loading scheme to study the post-yield behavior of cortical bone at tension [2] and compression [3]. However, few studies have reported post-yield behaviors of cortical bone in shear [4]. One of major challenges in shear tests of cortical bone is to achieve a uniform stress field over a test region. For example, the notches of the Iosipescu test may cause non-constant stress fields and locally high stresses when small amounts of bending are present [5]. The objective of this study was to develop the progressive loading scheme of shear in bone using an inclined double notch shear test, in which homogeneous shear stress fields were produced [5].

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Effects of Aging on the Subcortical Encoding of Stop Consonants

American Journal of Audiology ◽

10.1044/2020_aja-19-00044 ◽

2020 ◽

Vol 29 (3) ◽

pp. 391-403

Author(s):

Dania Rishiq ◽

Ashley Harkrider ◽

Cary Springer ◽

Mark Hedrick

Keyword(s):

Older Adults ◽

Repeated Measures ◽

Mixed Model ◽

Auditory Brainstem ◽

Auditory Brainstem Responses ◽

Aging Effects ◽

Formant Frequency ◽

Place Of Articulation ◽

Second Formant ◽

Effects Of Aging

Purpose The main purpose of this study was to evaluate aging effects on the predominantly subcortical (brainstem) encoding of the second-formant frequency transition, an essential acoustic cue for perceiving place of articulation. Method Synthetic consonant–vowel syllables varying in second-formant onset frequency (i.e., /ba/, /da/, and /ga/ stimuli) were used to elicit speech-evoked auditory brainstem responses (speech-ABRs) in 16 young adults ( M age = 21 years) and 11 older adults ( M age = 59 years). Repeated-measures mixed-model analyses of variance were performed on the latencies and amplitudes of the speech-ABR peaks. Fixed factors were phoneme (repeated measures on three levels: /b/ vs. /d/ vs. /g/) and age (two levels: young vs. older). Results Speech-ABR differences were observed between the two groups (young vs. older adults). Specifically, older listeners showed generalized amplitude reductions for onset and major peaks. Significant Phoneme × Group interactions were not observed. Conclusions Results showed aging effects in speech-ABR amplitudes that may reflect diminished subcortical encoding of consonants in older listeners. These aging effects were not phoneme dependent as observed using the statistical methods of this study.

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Age Differences in Eye Movements During Reading: Degenerative Problems or Compensatory Strategy?

European Psychologist ◽

10.1027/1016-9040/a000344 ◽

2019 ◽

Vol 24 (4) ◽

pp. 297-311

Author(s):

José David Moreno ◽

José A. León ◽

Lorena A. M. Arnal ◽

Juan Botella

Keyword(s):

Eye Movements ◽

Eye Movement ◽

Meta Analysis ◽

Age Groups ◽

Behavioral Changes ◽

Aging Effects ◽

Movement Data ◽

Sentence Reading ◽

The Difference ◽

Eye Movements During Reading

Abstract. We report the results of a meta-analysis of 22 experiments comparing the eye movement data obtained from young ( Mage = 21 years) and old ( Mage = 73 years) readers. The data included six eye movement measures (mean gaze duration, mean fixation duration, total sentence reading time, mean number of fixations, mean number of regressions, and mean length of progressive saccade eye movements). Estimates were obtained of the typified mean difference, d, between the age groups in all six measures. The results showed positive combined effect size estimates in favor of the young adult group (between 0.54 and 3.66 in all measures), although the difference for the mean number of fixations was not significant. Young adults make in a systematic way, shorter gazes, fewer regressions, and shorter saccadic movements during reading than older adults, and they also read faster. The meta-analysis results confirm statistically the most common patterns observed in previous research; therefore, eye movements seem to be a useful tool to measure behavioral changes due to the aging process. Moreover, these results do not allow us to discard either of the two main hypotheses assessed for explaining the observed aging effects, namely neural degenerative problems and the adoption of compensatory strategies.

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