Direct Measurements of the Stiffness of Echinoderm Sperm Flagella

1979 ◽  
Vol 79 (1) ◽  
pp. 235-243 ◽  
Author(s):  
MAKOTO OKUNO ◽  
YUKIO HIRAMOTO
Keyword(s):  
Young’S Modulus ◽  
Inorganic Phosphate ◽  
Sea Water ◽  
Flexural Rigidity ◽  
Young's Modulus ◽  
Entire Length ◽  
Free Solution ◽  
Direct Measurements ◽  
Hemicentrotus Pulcherrimus

1. The stiffness (flexural rigidity) of some echinoderm sperm flagella was measured, using a flexible glass microneedle. 2. Values of 0.3-1.5 × 10−21 N m2 were obtained for the stiffness of live flagella which were immobilized with CO2-saturated sea water. 3. The immobilized live flagellum was uniform in stiffness along its entire length, except in a particular plane of imposed bending in which flexible regions were observed. 4. Demembranated flagella (Hemicentrotus pulcherrimus) in an ATP-free solution were about ten times stiffer (1.1 × 10−20 N m2) than immobilized live ones (0.5-0.9 × 10−21 N m2). The stiffness was decreased by addition of ATP to the solution and became equivalent to that of live ones when the solution contained 10 mM ATP. 5. In the demembranated flagella, the effects of ADP and ATP on the stiffness were similar. Other nucleotide phosphates and inorganic phosphate did not reduce the stiffness. 6. Young's modulus of microtubules is estimated to be 2.5 × 109 Nm2 on the basis that the microtubules have no tight connexion with one another in immobilized live flagella.

The Mechanical Properties of the Cell Surface

1955 ◽  
Vol 32 (4) ◽  
pp. 734-750 ◽  
Author(s):  
J. M. MITCHISON ◽  
M. M. SWANN
Keyword(s):  
Cell Surface ◽  
Young’S Modulus ◽  
Sea Water ◽  
Young's Modulus ◽  
Contractile Ring ◽  
A Value ◽  
Sudden Rise ◽  
Slow Rise ◽  
Stage Yield ◽  
Sperm Aster

1. Measurements with the cell elastimeter on the stiffness of the cell membrane of fertilized sea-urchin eggs show the following general features. There is a sudden rise at fertilization, followed by a fall during the early sperm aster stage to the lowest value reached during development (a Young's modulus of about 0.58 x 104 dynes/cm.2). The stiffness rises slowly until metaphase, after which it rises rapidly to reach a maximum during late anaphase and early cleavage (6.81 x 104 dynes/cm.2). During the later stages of cleavage the stiffness falls again and reaches a value in the second interphase which is about twice as high as in the first interphase. Masurements on naked eggs in calcium-free sea water indicate that the slow rise in metaphase is due to the development of the hyaline layer. 2. Measurements on swollen and shrunken eggs at cleavage indicate that there is no interal pressure in the eggs at this stage, but similar experiments with eggs at the sperm aster stage yield anomalous results. Observations on the wrinkling point in shrunken eggs show that the maximum possible internal pressure is 19 dynes/cm.2 for sperm aster eggs and 500 dynes/cm.2 for cleaving eggs. 3. The bearing of these results on various theories of the mechanism of cleavage is briefly discussed. The rise in Young's modulus of the whole cell surface at cleavage argues against theories depending on the action of the spindle and asters, and against theories proposing a contractile ring in the surface. The rise is, however, what might be expected on the basis of the expanding membrane theory.

Flexural Rigidity and Elastic Constant of Cilia

1972 ◽  
Vol 56 (2) ◽  
pp. 459-467 ◽  
Author(s):  
SHOJI A. BABA
Keyword(s):  
Elastic Constant ◽  
Young’S Modulus ◽  
Flexural Rigidity ◽  
Young's Modulus ◽  
Recovery Phase

1. The flexural rigidity of the large abfrontal cilia of Mytilus has been measured with a flexible glass micro-needle. 2. The same cilium has similar values to the flexural rigidity irrespective of the phases of beat cycle (including the recovery phase) and of the direction of force applied. 3. The values of 3-13 x 10-9 dyne. cm2 have been obtained for the flexural rigidity of compound cilia of various sizes; 2-3 x 10-10 dyne.cm2 for that of the component cilia. 4. The Young's modulus of the microtubule is estimated to be 5-9 x 1010 dyne/cm2 on the basis that the outer doublet microtubules are tightly connected with one another.

scholarly journals Mechanical Properties of Isolated Primary Cilia Measured by Micro-tensile Test and Atomic Force Microscopy

2021 ◽  
Vol 9 ◽  
Author(s):  
Tien-Dung Do ◽  
Jimuro Katsuyoshi ◽  
Haonai Cai ◽  
Toshiro Ohashi
Keyword(s):  
Mechanical Properties ◽  
Atomic Force Microscopy ◽  
Young’S Modulus ◽  
Primary Cilia ◽  
Flexural Rigidity ◽  
Young's Modulus ◽  
Optical Trap ◽  
Mechanical Stimuli ◽  
Force Microscopy ◽  
Atomic Force

Mechanotransduction is a well-known mechanism by which cells sense their surrounding mechanical environment, convert mechanical stimuli into biochemical signals, and eventually change their morphology and functions. Primary cilia are believed to be mechanosensors existing on the surface of the cell membrane and support cells to sense surrounding mechanical signals. Knowing the mechanical properties of primary cilia is essential to understand their responses, such as sensitivity to mechanical stimuli. Previous studies have so far conducted flow experiments or optical trap techniques to measure the flexural rigidity EI (E: Young’s modulus, I: second moment of inertia) of primary cilia; however, the flexural rigidity is not a material property of materials and depends on mathematical models used in the determination, leading to a discrepancy between studies. For better characterization of primary cilia mechanics, Young’s modulus should be directly and precisely measured. In this study, the tensile Young’s modulus of isolated primary cilia is, for the first time, measured by using an in-house micro-tensile tester. The different strain rates of 0.01–0.3 s−1 were applied to isolated primary cilia, which showed a strain rate–dependent Young’s modulus in the range of 69.5–240.0 kPa on average. Atomic force microscopy was also performed to measure the local Young’s modulus of primary cilia, showing the Young’s modulus within the order of tens to hundreds of kPa. This study could directly provide the global and local Young’s moduli, which will benefit better understanding of primary cilia mechanics.

Mechanical properties of FeAlSi powders prepared by mechanical alloying from different initial feedstock materials

2019 ◽  
Vol 107 (2) ◽  
pp. 207 ◽  
Author(s):  
Jaroslav Čech ◽  
Petr Haušild ◽  
Miroslav Karlík ◽  
Veronika Kadlecová ◽  
Jiří Čapek ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Mechanical Alloying ◽  
Young’S Modulus ◽  
Milling Time ◽  
Young's Modulus ◽  
Element Model ◽  
X Ray Diffraction ◽  
X Ray ◽  
Powder Particles ◽  
Complete Homogenization

FeAl20Si20 (wt.%) powders prepared by mechanical alloying from different initial feedstock materials (Fe, Al, Si, FeAl27) were investigated in this study. Scanning electron microscopy, X-ray diffraction and nanoindentation techniques were used to analyze microstructure, phase composition and mechanical properties (hardness and Young’s modulus). Finite element model was developed to account for the decrease in measured values of mechanical properties of powder particles with increasing penetration depth caused by surrounding soft resin used for embedding powder particles. Progressive homogenization of the powders’ microstructure and an increase of hardness and Young’s modulus with milling time were observed and the time for complete homogenization was estimated.

Degradation of Rocks, Through Cracking Caused by Differential Thermal Expansion, in Relation to Nuclear Waste Repositories

1981 ◽  
Vol 6 ◽  
Author(s):  
J.R. Mclaren ◽  
R.W. Davidge ◽  
I. Titchell ◽  
K. Sincock ◽  
A. Bromley
Keyword(s):  
Thermal Expansion ◽  
Grain Boundary ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Crack Density ◽  
Granitic Rocks ◽  
Multiphase Materials ◽  
Thermal Expansion Behaviour ◽  
Waste Repositories ◽  
Expansion Behaviour

ABSTRACTHeating to temperatures up to 500°C, gives a reduction in Young's modulus and increase in permeability of granitic rocks and it is likely that a major reason is grain boundary cracking. The cracking of grain boundary facets in polycrystalline multiphase materials showing anisotropic thermal expansion behaviour is controlled by several microstructural factors in addition to the intrinsic thermal and elastic properties. Of specific interest are the relative orientations of the two grains meeting at the facet, and the size of the facet; these factors thus introduce two statistical aspects to the problem and these are introduced to give quantitative data on crack density versus temperature. The theory is compared with experimental measurements of Young's modulus and permeability for various rocks as a function of temperature. There is good qualitative agreement, and the additional (mainly microstructural) data required for a quantitative comparison are defined.

Is it necessary to calculate Young’s modulus in AFM nanoindentation experiments regarding biological samples?

2020 ◽  
Vol 12 ◽  
Author(s):  
S.V. Kontomaris ◽  
A. Malamou ◽  
A. Stylianou
Keyword(s):  
Young’S Modulus ◽  
Biological Samples ◽  
Young's Modulus ◽  
Reference Sample ◽  
Nonlinear Behavior ◽  
Accurate Method ◽  
Accurate Solution ◽  
Hertz Model ◽  
Work Done

Background: The determination of the mechanical properties of biological samples using Atomic Force Microscopy (AFM) at the nanoscale is usually performed using basic models arising from the contact mechanics theory. In particular, the Hertz model is the most frequently used theoretical tool for data processing. However, the Hertz model requires several assumptions such as homogeneous and isotropic samples and indenters with perfectly spherical or conical shapes. As it is widely known, none of these requirements are 100 % fulfilled for the case of indentation experiments at the nanoscale. As a result, significant errors arise in the Young’s modulus calculation. At the same time, an analytical model that could account complexities of soft biomaterials, such as nonlinear behavior, anisotropy, and heterogeneity, may be far-reaching. In addition, this hypothetical model would be ‘too difficult’ to be applied in real clinical activities since it would require very heavy workload and highly specialized personnel. Objective: In this paper a simple solution is provided to the aforementioned dead-end. A new approach is introduced in order to provide a simple and accurate method for the mechanical characterization at the nanoscale. Method: The ratio of the work done by the indenter on the sample of interest to the work done by the indenter on a reference sample is introduced as a new physical quantity that does not require homogeneous, isotropic samples or perfect indenters. Results: The proposed approach, not only provides an accurate solution from a physical perspective but also a simpler solution which does not require activities such as the determination of the cantilever’s spring constant and the dimensions of the AFM tip. Conclusion: The proposed, by this opinion paper, solution aims to provide a significant opportunity to overcome the existing limitations provided by Hertzian mechanics and apply AFM techniques in real clinical activities.

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