scholarly journals Mechanical Properties of the Sarcolemma and Myoplasm in Frog Muscle as a Function of Sarcomere Length

1972 ◽  
Vol 59 (5) ◽  
pp. 559-585 ◽  
Author(s):  
Stanley I. Rapoport
Keyword(s):  
Elastic Modulus ◽  
Fiber Length ◽  
Elastic Moduli ◽  
Sarcomere Length ◽  
Fiber Surface ◽  
Frog Muscle ◽  
Fiber Tension ◽  
Resistance To Deformation ◽  
Longitudinal Elastic Modulus ◽  
Tension Curve

The elastimeter method was applied to the single muscle fiber of the frog semitendinosus to obtain the elastic moduli of the sarcolemma and myoplasm, as well as their relative contributions to resting fiber tension at different extensions. A bleb which was sucked into a flat-mouthed pipette at the fiber surface separated into an external sarcolemmal membrane and a thick inner myoplasmic region. Measurements showed that the sarcolemma does not contribute to intact fiber tension at sarcomere lengths below 3 µ. It was estimated that the sarcolemma contributed on the order of 10% to intact fiber tension at sarcomere lengths between 3 and 3.75 µ, and more so with further extension. Between these sarcomere lengths, the sarcolemma can be linearly extended and has a longitudinal elastic modulus of 5 x 106 dyne/cm2 (assuming a thickness of 0.1 µ). Resistance to deformation of the inner bleb region is due to myoplasmic elasticity. The myoplasmic elastic modulus was estimated by use of a model and was used to predict a fiber length-tension curve which agreed approximately with observations.

Myofilament overlap in swimming carp. I. Myofilament lengths of red and white muscle

1991 ◽  
Vol 260 (2) ◽  
pp. C283-C288 ◽  
Author(s):  
A. A. Sosnicki ◽  
K. E. Loesser ◽  
L. C. Rome
Keyword(s):  
Actin Filaments ◽  
Sarcomere Length ◽  
White Muscle ◽  
Frog Muscle ◽  
Myosin Filament ◽  
Thin Filaments ◽  
Thin Sections ◽  
Myosin Filaments ◽  
Tension Curve ◽  
Red And White Muscles

To assess myofilament overlap during locomotion, we estimated the length of myosin and actin filaments in axial red and white muscle of carp. Myosin filament lengths were 1.52 +/- 0.009 and 1.50 +/- 0.037 micron (means +/- SD) in the red and white muscle, respectively, as measured from thin sections. After correction for shrinkage (using the troponin-based 385-A axial periodicity), thin filaments were 0.96 +/- 0.009 and 0.97 +/- 0.023 micron in the red and white muscles, respectively. Filaments were also isolated from the white muscle and negatively stained. Myosin filaments were 1.56 +/- 0.025 microns, and actin filaments were 0.99 +/- 0.024 micron in length. The data from thin sections and isolated filaments agreed within 2% for actin and 4% for myosin filaments. The number of actin filament periods (24 for the red and white muscle) and the length of the filaments are the same as in frog. This suggests that the classic sarcomere length-tension curve of frog muscle may be used to estimate the functional properties of carp red and white muscle.

Morphological Basis of the Disparity Between Muscle Length and Sarcomere Length in the Myocardium

1973 ◽  
Vol 31 ◽  
pp. 422-423
Author(s):  
G.E. Adomian ◽  
L. Chuck ◽  
W.W. Pannley
Keyword(s):  
Cardiac Muscle ◽  
Sarcomere Length ◽  
Muscle Length ◽  
Contractile Force ◽  
Direct Function ◽  
Morphological Basis ◽  
Tension Curve

Sonnenblick, et al, have shown that sarcomeres change length as a function of cardiac muscle length along the ascending portion of the length-tension curve. This allows the contractile force to be expressed as a direct function of sarcomere length. Below L max, muscle length is directly related to sarcomere length at lengths greater than 85% of optimum. However, beyond the apex of the tension-length curve, i.e. L max, a disparity occurs between cardiac muscle length and sarcomere length. To account for this disproportionate increase in muscle length as sarcomere length remains relatively stable, the concept of fiber slippage was suggested as a plausible explanation. These observations have subsequently been extended to the intact ventricle.

scholarly journals The Effects of Creep on Elastic Modulus Measurement Using Nanoindentation

2000 ◽  
Vol 649 ◽  
Author(s):  
G. Feng ◽  
A.H.W. Ngan
Keyword(s):  
Elastic Modulus ◽  
Elastic Deformation ◽  
Elastic Moduli ◽  
Holding Time ◽  
Time Dependent ◽  
Nanoindentation Test ◽  
Modification Method ◽  
Unloading Rate ◽  
Modulus Measurement

ABSTRACTDuring the unloading segment of nanoindentation, time dependent displacement (TDD) accompanies elastic deformation. Consequently the modulus calculated by the Oliver-Pharr scheme can be overestimated. In this paper we present evidences for the influence of the measured modulus by TDD. A modification method is also presented to correct for the effects of TDD by extrapolating the TDD law in the holding process to the beginning of the unloading process. Using this method, the appropriate holding time and unloading rate can be estimated for nanoindentation test to minimise the effects of TDD. The elastic moduli of three materials computed by the modification method are compared with the results without considering the TDD effects.

Muscle capillary-to-fiber perimeter ratio: morphometry

1991 ◽  
Vol 261 (5) ◽  
pp. H1617-H1625 ◽  
Author(s):  
O. Mathieu-Costello ◽  
C. G. Ellis ◽  
R. F. Potter ◽  
I. C. MacDonald ◽  
A. C. Groom
Keyword(s):  
Surface Area ◽  
Muscle Fiber ◽  
Sarcomere Length ◽  
Fiber Surface ◽  
Capillary Surface ◽  
Capillary Length ◽  
Hindlimb Muscles ◽  
Using Data ◽  
Degree Of Extension

It is known that a substantial amount of capillary tortuosity is found in shortened muscles. However, the increased capillary length and surface area contributed by tortuosity and branching are seldom taken into account when capillarity is estimated and/or blood-tissue exchange is modeled in muscles. In this paper, we sought morphometric estimates of capillarity in transverse sections that incorporated data on capillary geometry. We derived equations to estimate capillary perimeter per fiber perimeter (i.e., capillary-to-fiber perimeter ratio) in transverse sections. We show how capillary-to-fiber perimeter ratio is related to capillary surface per fiber surface, i.e., to the amount of capillary surface available for exchange per muscle fiber surface area, and how it can be obtained by morphometry. Because capillary tortuosity and fiber perimeter are both a function of sarcomere length, the degree of extension or shortening of muscle samples obviously needs to be taken into account when capillary-to-fiber perimeter ratio is compared between muscles and/or samples. Using data currently available on capillary length and diameter with fiber shortening and extension, we show that it is a feature of capillary-to-fiber perimeter ratio to change relatively little with sarcomere length. As sarcomere length decreases from 2.80 to 1.58 microns in perfusion-fixed hindlimb muscles of rats, capillary and fiber perimeters in transverse sections increase substantially, whereas the ratio between the two variables, capillary-to-fiber perimeter ratio, changes only less than or equal to 10-15%.(ABSTRACT TRUNCATED AT 250 WORDS)

Relation of Cotton Fiber Properties to Sliver Cohesion

1977 ◽  
Vol 47 (11) ◽  
pp. 755-760 ◽  
Author(s):  
Reba Lawson ◽  
Smith Worley ◽  
H. H. Ramey
Keyword(s):  
Fiber Length ◽  
Stepwise Regression ◽  
Statistical Evaluation ◽  
Fiber Surface ◽  
Cohesive Force ◽  
Independent Variables ◽  
Fiber Properties ◽  
Positive Correlations ◽  
Relationship Of ◽  
The Relationship

A statistical evaluation was made of the relationship of certain fiber properties to cohesive force and coefficient of variation of cohesive force. Significant positive correlations were found between the cohesive force and fiber length, tenacity, and fiber yellowness (+b); negative correlations were found with fiber perimeter and reflectance (Rd). When length, colorimeter values, and Micronaire readings were used as independent variables in a stepwise regression program, 53% of the variation in the cohesive force could be explained by upper half mean length and Rd. The addition of other fiber properties whose measurement was influenced by fiber surface properties increased the explainable variation in the cohesive force to 71%.

Consistent red luminescence in π-conjugated polymers with tuneable elastic moduli over five orders of magnitude

2020 ◽  
Vol 7 (5) ◽  
pp. 1421-1426 ◽  
Author(s):  
Zhenfeng Guo ◽  
Akira Shinohara ◽  
Chengjun Pan ◽  
Florian J. Stadler ◽  
Zhonghua Liu ◽  
...  
Keyword(s):  
Elastic Modulus ◽  
Conjugated Polymers ◽  
Elastic Moduli ◽  
Luminescent Properties ◽  
Side Chains ◽  
Wide Range ◽  
Alkyl Side Chains ◽  
Red Luminescence

Bulky but flexible alkyl side chains enable π-conjugated polymers to possess wide-range elastic modulus tuneability, yet consistent red luminescent properties.

Coarse Aggregate Effects on Elastic Moduli of Concrete

1996 ◽  
Vol 1547 (1) ◽  
pp. 29-34 ◽  
Author(s):  
Bouzid Choubane ◽  
Chung-Lung Wu ◽  
Mang Tia
Keyword(s):  
Elastic Modulus ◽  
Dynamic Modulus ◽  
Laboratory Testing ◽  
Elastic Moduli ◽  
Coarse Aggregate ◽  
Textured Surface ◽  
Test Program ◽  
Static Modulus ◽  
Aggregate Effects ◽  
Strength And Stiffness

The results of a laboratory testing program carried out to investigate the effect of coarse aggregate types on the elastic modulus of typical pavement concretes are presented. The elastic modulus was determined in both flexure and compression using static and dynamic means. Three different mixes, made using three different aggregates, were compared. The water-cement ratio was kept at 0.53 throughout the test program. The results showed that within the tested range, the aggregate type significantly affected the studied properties of concrete. Calera aggregate (a dense limestone) with its rough-textured surface and angular shape produced a concrete with higher strength and stiffness than those of concretes made with Brooksville aggregate (a porous limestone) and river gravel. In addition, the measured dynamic modulus in compression was significantly different from that in flexure. Also, in flexure, the dynamic modulus was higher than the static modulus by an average of 23 percent, whereas in compression, the dynamic modulus appeared to be in the same range as the static modulus. The change in frequency from 1 to 7 Hz did not have a significant influence on the dynamic modulus.

scholarly journals A Novel Toolkit for Characterizing the Mechanical and Electrical Properties of Engineered Neural Tissues

Biosensors ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 51 ◽  
Author(s):  
Meghan Robinson ◽  
Karolina Valente ◽  
Stephanie Willerth
Keyword(s):  
Elastic Modulus ◽  
Electrical Properties ◽  
Elastic Moduli ◽  
Direct Method ◽  
Hydrogel Scaffolds ◽  
Force Microscopy ◽  
Mechanical And Electrical Properties ◽  
Atomic Force ◽  
Neural Tissues ◽  
Electrical Signaling

We have designed and validated a set of robust and non-toxic protocols for directly evaluating the properties of engineered neural tissue. These protocols characterize the mechanical properties of engineered neural tissues and measure their electrophysical activity. The protocols obtain elastic moduli of very soft fibrin hydrogel scaffolds and voltage readings from motor neuron cultures. Neurons require soft substrates to differentiate and mature, however measuring the elastic moduli of soft substrates remains difficult to accurately measure using standard protocols such as atomic force microscopy or shear rheology. Here we validate a direct method for acquiring elastic modulus of fibrin using a modified Hertz model for thin films. In this method, spherical indenters are positioned on top of the fibrin samples, generating an indentation depth that is then correlated with elastic modulus. Neurons function by transmitting electrical signals to one another and being able to assess the development of electrical signaling serves is an important verification step when engineering neural tissues. We then validated a protocol wherein the electrical activity of motor neural cultures is measured directly by a voltage sensitive dye and a microplate reader without causing damage to the cells. These protocols provide a non-destructive method for characterizing the mechanical and electrical properties of living spinal cord tissues using novel biosensing methods.

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