Accommodation and presbyopia in the human eye 1: Evaluation of in vivo measurement techniques

1989 ◽  
Vol 28 (6) ◽  
pp. 1097 ◽  
Author(s):  
Jane F. Koretz ◽  
Paul L. Kaufman ◽  
Michael W. Neider ◽  
Patrick A. Goeckner
Keyword(s):  
Measurement Techniques ◽  
Human Eye ◽  
In Vivo Measurement

Noncontact Determination of the Mechanical Properties of the Human Vocal Folds

2008 ◽  
Author(s):  
Shinji Deguchi ◽  
Kazutaka Kawashima
Keyword(s):  
Mechanical Properties ◽  
Vocal Fold ◽  
Measurement Techniques ◽  
Voice Quality ◽  
Vocal Folds ◽  
In Vivo Measurement ◽  
In Vitro Measurements ◽  
Excited Oscillation

Mechanical properties of the vocal folds (such as stiffness or viscoelastic properties) play an essential role in phonation. They affect not only voice quality but also onset threshold of vocal fold self-excited oscillation, a sound source of voice [1]. Many experimental data on the mechanical properties have been reported so far, in which in vitro [2] or in vivo measurement techniques [3] were employed. In vitro measurements give us detailed information on the mechanical properties, yet it would be required to consider possible loss of freshness of the specimen. Meanwhile, current in vivo measurement methods utilize a thin probe to deform the vocal fold tissue located at the back of the throat and hence need technical skills for the surveyor to successfully obtain its loading-deformation relationship.

scholarly journals Review of current in vivo measurement techniques for quantifying enteric methane emission from ruminants

2016 ◽  
Vol 219 ◽  
pp. 13-30 ◽  
Author(s):  
K.J. Hammond ◽  
L.A. Crompton ◽  
A. Bannink ◽  
J. Dijkstra ◽  
D.R. Yáñez-Ruiz ◽  
...  
Keyword(s):  
Methane Emission ◽  
Measurement Techniques ◽  
In Vivo Measurement ◽  
Enteric Methane

scholarly journals Biometric Measurement of Anterior Segment: A Review

Sensors ◽  
2020 ◽  
Vol 20 (15) ◽  
pp. 4285
Author(s):  
Bin Liu ◽  
Chengwei Kang ◽  
Fengzhou Fang
Keyword(s):  
High Speed ◽  
Anterior Segment ◽  
Future Research ◽  
Basic Principles ◽  
Human Eye ◽  
In Vivo Measurement ◽  
Research Perspectives ◽  
Scattering Effects ◽  
Fine Resolution

Biometric measurement of the anterior segment is of great importance for the ophthalmology, human eye modeling, contact lens fitting, intraocular lens design, etc. This paper serves as a comprehensive review on the historical development and basic principles of the technologies for measuring the geometric profiles of the anterior segment. Both the advantages and drawbacks of the current technologies are illustrated. For in vivo measurement of the anterior segment, there are two main challenges that need to be addressed to achieve high speed, fine resolution, and large range imaging. One is the motion artefacts caused by the inevitable and random human eye movement. The other is the serious multiple scattering effects in intraocular turbid media. The future research perspectives are also outlined in this paper.

scholarly journals Parallel Fourier domain optical coherence tomography for in vivo measurement of the human eye

2005 ◽  
Vol 13 (4) ◽  
pp. 1131 ◽  
Author(s):  
Branislav Grajciar ◽  
Michael Pircher ◽  
Adolf F. Fercher ◽  
Rainer A. Leitgeb
Keyword(s):  
Optical Coherence Tomography ◽  
Fourier Domain ◽  
Optical Coherence ◽  
Human Eye ◽  
In Vivo Measurement

scholarly journals In Vivo Measurement of Neurochemical Abnormalities in the Hippocampus in a Rat Model of Cuprizone-Induced Demyelination

Diagnostics ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 45
Author(s):  
Do-Wan Lee ◽  
Jae-Im Kwon ◽  
Chul-Woong Woo ◽  
Hwon Heo ◽  
Kyung Won Kim ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Rat Model ◽  
Resonance Spectroscopy ◽  
Chow Diet ◽  
Gamma Aminobutyric Acid ◽  
Sprague Dawley ◽  
In Vivo Measurement ◽  
Hippocampal Lesions ◽  
Total Creatine

This study quantitatively measured the changes in metabolites in the hippocampal lesions of a rat model of cuprizone-induced demyelination as detected using in vivo 7 T proton magnetic resonance spectroscopy. Nineteen Sprague Dawley rats were randomly divided into two groups and fed a normal chow diet or cuprizone (0.2%, w/w) for 7 weeks. Demyelinated hippocampal lesions were quantitatively measured using a 7 T magnetic resonance imaging scanner. All proton spectra were quantified for metabolite concentrations and relative ratios. Compared to those in the controls, the cuprizone-induced rats had significantly higher concentrations of glutamate (p = 0.001), gamma-aminobutyric acid (p = 0.019), and glutamate + glutamine (p = 0.001); however, creatine + phosphocreatine (p = 0.006) and myo-inositol (p = 0.001) concentrations were lower. In addition, we found that the glutamine and glutamate complex/total creatine (p < 0.001), glutamate/total creatine (p < 0.001), and GABA/total creatine (p = 0.002) ratios were significantly higher in cuprizone-treated rats than in control rats. Our results showed that cuprizone-induced neuronal demyelination may influence the severe abnormal metabolism in hippocampal lesions, and these responses could be caused by microglial activation, mitochondrial dysfunction, and astrocytic necrosis.

scholarly journals Towards planning of osteotomy around the knee with quantitative inclusion of the adduction moment: a biomechanical approach

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Margit Biehl ◽  
Philipp Damm ◽  
Adam Trepczynski ◽  
Stefan Preiss ◽  
Gian Max Salzmann
Keyword(s):  
Gait Analysis ◽  
Measurement Data ◽  
Frontal Plane ◽  
Medial Compartment ◽  
Knee Adduction Moment ◽  
In Vivo Measurement ◽  
Force Ratio ◽  
Leg Alignment ◽  
Alignment Angle

Abstract Purpose Despite practised for decades, the planning of osteotomy around the knee, commonly using the Mikulicz-Line, is only empirically based, clinical outcome inconsistent and the target angle still controversial. A better target than the angle of frontal-plane static leg alignment might be the external frontal-plane lever arm (EFL) of the knee adduction moment. Hypothetically assessable from frontal-plane-radiograph skeleton dimensions, it might depend on the leg-alignment angle, the hip-centre-to-hip-centre distance, the femur- and tibia-length. Methods The target EFL to achieve a medial compartment force ratio of 50% during level-walking was identified by relating in-vivo-measurement data of knee-internal loads from nine subjects with instrumented prostheses to the same subjects’ EFLs computed from frontal-plane skeleton dimensions. Adduction moments derived from these calculated EFLs were compared to the subjects’ adduction moments measured during gait analysis. Results Highly significant relationships (0.88 ≤ R2 ≤ 0.90) were found for both the peak adduction moment measured during gait analysis and the medial compartment force ratio measured in vivo to EFL calculated from frontal-plane skeleton dimensions. Both correlations exceed the respective correlations with the leg alignment angle, EFL even predicts the adduction moment’s first peak. The guideline EFL for planning osteotomy was identified to 0.349 times the epicondyle distance, hence deducing formulas for individualized target angles and Mikulicz-Line positions based on full-leg radiograph skeleton dimensions. Applied to realistic skeleton geometries, widespread results explain the inconsistency regarding correction recommendations, whereas results for average geometries exactly meet the most-consented “Fujisawa-Point”. Conclusion Osteotomy outcome might be improved by planning re-alignment based on the provided formulas exploiting full-leg-radiograph skeleton dimensions.

Sign in / Sign up

Export Citation Format

Share Document