Change Of Force Distribution Research Articles

Experimental and numerical analysis of a non-dismantling repair method for ancient timber arch lounge bridges

Ancient timber arch lounge bridges are precious cultural heritages in China. The woven arch is the main load-bearing structure of the timber arch lounge bridges, and repairing the woven arch is a very important work in the protection of the ancient timber arch lounge bridges, yet there are few studies on the repair methods. This paper proposes a non-dismantling repair method for the woven arch to meet the repair principle of cultural relics, with minimal repair and minimal interference. This method can be used to replace a small number of the components individually. A strengthened spliced log with a lap joint is used to replace the damaged longitudinal log of the woven arch without dismantling the entire structure. Large-scale model experiments and finite element analyses were performed in this paper to study the effects of the repair method on the woven arch. Deflection and force distribution changes of the woven arch caused by the replacement of the longitudinal logs of the woven arch were studied. The results of finite element analyses are in good agreement with the experimental results. The results show that, under dead load, dismantling a longitudinal log of the woven arch has little interference with the deflection. After dismantling a member of the woven arch, the axial force of the dismantled member will transfer to the adjacent members in the same system. The bearing capacity of the repaired woven arch is comparable to the intact woven arch.

The effects of technological and traditional feedback on back squat performance in untrained women

BackgroundRecently, a novel method for improving movement quality called open-ended augmented feedback has been introduced. However, the effects of using such feedback in a training intervention have not yet been examined. The aim of this study was to assess the changes in performance and movement quality following a five-week resistance-training program with either (1) technological feedback or (2) traditional, verbal feedback from an experienced trainer.MethodsNineteen untrained females (age: 21.84 ± 2.24 years, height: 169.95 ± 5.92 cm, body mass: 65.05 ± 7.93 kg) randomly allocated to one of the two conditions completed five weeks of training with two weekly sessions. Pre- and post-intervention, participants were tested for physical performance (i.e., back squat and isometric mid-thigh pull strength) and movement quality parameters (weight distribution, center of gravity variation, and subjective rating of the back squat technique).ResultsBoth groups similarly increased the training resistance throughout the intervention (p < 0.01), as well as strength in the back squat (technological feedback group: effect size (ES) = 1.31, p = 0.002; traditional feedback group: ES = 1.48, p = 0.002). Only the traditional feedback group increased isometric mid-thigh pull strength (ES = 1.11, p = 0.008) and subjectively rated lifting technique at the same load (p = 0.046). No changes in force distribution (p = 0.062–0.993) or center of gravity variation (p = 0.160–0.969) occurred in either group when lifting the same absolute loads at post-test. However, both groups displayed a greater variation in center of gravity when lifting the same relative load at post-test (technological feedback group: p < 0.001; traditional feedback group: p = 0.006). No differences were found between the groups for any of the observed changes (p = 0.205–0.401).ConclusionsFive weeks of back-squat training with verbal feedback increased isometric mid-thigh pull strength and subjectively rated lifting technique from pre- to post-test, whereas technological feedback did not. Both methods improved back squat strength and training resistance. For resistance-training beginners, the choice between feedback methods should be based on the desired outcomes and the availability of expertise and equipment.

Impact of Anchor Location on Mitral Neochordae Forces: An In Vitro Study

PurposeThis study examined changes in force distribution between the neochordae corresponding to different ventricular anchor locations. DescriptionSeven porcine mitral valves were mounted in a left heart simulator. Neochordae (expanded polytetrafluoroethylene) originated from either a simulated left ventricular apex, papillary muscle base, or papillary muscle tip location. The neochordae were attached at three sites along the P2 leaflet segment: P2Lateral; P2Center, and P2Medial. Mitral regurgitation was induced by cutting posterior leaflet P2 marginal chordae. The forces on each neochord required to restore normal mitral valve coaptation were quantified for different ventricular anchoring origins and leaflet insertion sites. EvaluationThe results showed that under both normotensive and hypertensive conditions, the force exerted was much higher at P2Center than either P2Lateral or P2Medial, independent of ventricular anchor location. Also, forces on both P2Lateral and P2Medial were not statistically different. ConclusionsArtificial neochordae treatment for all anchoring locations was effective in correcting induced mitral regurgitation. The P2 central neochordae had a significantly higher force than both lateral neochords under all conditions.

EphA2 and Ephrin-A5 Guide Eye Lens Suture Alignment and Influence Whole Lens Resilience.

PurposeFine focusing of light by the eye lens onto the retina relies on the ability of the lens to change shape during the process of accommodation. Little is known about the cellular structures that regulate elasticity and resilience. We tested whether Eph–ephrin signaling is involved in lens biomechanical properties.MethodsWe used confocal microscopy and tissue mechanical testing to examine mouse lenses with genetic disruption of EphA2 or ephrin-A5.ResultsConfocal imaging revealed misalignment of the suture between each shell of newly added fiber cells in knockout lenses. Despite having disordered sutures, loss of EphA2 or ephrin-A5 did not affect lens stiffness. Surprisingly, knockout lenses were more resilient and recovered almost completely after load removal. Confocal microscopy and quantitative image analysis from live lenses before, during, and after compression revealed that knockout lenses had misaligned Y-sutures, leading to a change in force distribution during compression. Knockout lenses displayed decreased separation of fiber cell tips at the anterior suture at high loads and had more complete recovery after load removal, which leads to improved whole-lens resiliency.ConclusionsEphA2 and ephrin-A5 are needed for normal patterning of fiber cell tips and the formation of a well-aligned Y-suture with fiber tips stacked on top of previous generations of fiber cells. The misalignment of lens sutures leads to increased resilience after compression. The data suggest that alignment of the Y-suture may constrain the overall elasticity and resilience of the lens.

Effect of Backstay on Tall Structure with Podium Structure

In a multi-functional tall building, generally the building has a more extensive plan area and higher lateral resistance at the lower story level than the above story levels. So, the scope of this study is to understand the realistic behavior of such structures under lateral loads considering the backstay effect as per IS: 16700(2017). A Sensitivity Analysis was performed as per IS: 16700(2017) provisions by considering the stiffness parameters given in code to understand the changes in the shear force distribution among structural elements when the tower and Podium are modeled together. The changes in the force distribution are compared with the structure without the backstay effect. At the podium-tower interface level, the amount of backstay forces developed is also presented in this paper, along with the impact on backstay forces with changes in the lateral resistances by changing floor diaphragm thickness and by changing the podium area.

Mechanochemical control of epidermal stem cell divisions by B-plexins

The precise spatiotemporal control of cell proliferation is key to the morphogenesis of epithelial tissues. Epithelial cell divisions lead to tissue crowding and local changes in force distribution, which in turn suppress the rate of cell divisions. However, the molecular mechanisms underlying this mechanical feedback are largely unclear. Here, we identify a critical requirement of B-plexin transmembrane receptors in the response to crowding-induced mechanical forces during embryonic skin development. Epidermal stem cells lacking B-plexins fail to sense mechanical compression, resulting in disinhibition of the transcriptional coactivator YAP, hyperproliferation, and tissue overgrowth. Mechanistically, we show that B-plexins mediate mechanoresponses to crowding through stabilization of adhesive cell junctions and lowering of cortical stiffness. Finally, we provide evidence that the B-plexin-dependent mechanochemical feedback is also pathophysiologically relevant to limit tumor growth in basal cell carcinoma, the most common type of skin cancer. Our data define a central role of B-plexins in mechanosensation to couple cell density and cell division in development and disease.

Discrete element modelling of desiccation cracking in thin clay layer under different basal boundary conditions

This study aims to investigate the effect of basal boundary conditions on the initiation and propagation of desiccation cracking along the vertical direction in thin clay layer using discrete element method (DEM). A two-dimensional discrete model was proposed considering shrinkage kinetics and property change during the drying process. Different basal boundary constraints were simulated by applying bond between the soil particles and the fixed base particles of difference sizes. The simulation results were compared with the laboratory experiments. The results showed that the model can reproduce the main trend of desiccation process. Larger base particles produced more cracks in the specimen. Both cracks initiated from the top surface and cracks initiated from the bottom soil-base interface were observed and discriminated in the simulation. The model revealed the development of bottom-initiated cracks and unpenetrated cracks beneath the surface that may be neglected in traditional cracking simulations. The study suggests that the different initiation position of cracks is associated with the change of force distribution inside the specimen. Moreover, the effects of different boundary properties (the geometrical roughness, the frictional coefficient and the bond strength), particle density change and evaporation gradient on model performance were investigated.

Effect of Tread Design Changes on Tire Patch Dynamics at High Speeds Using a Dynamic Contact Force Measurement Rig

ABSTRACT The dynamic effects at the tire contact patch are one of the most difficult factors of a tire to measure. Generally, only the total forces at the tire axle are captured during the tests. There are a few methods for identifying the force distribution at the tire contact patch, but most of these methods are limited to static tests or dynamic tests at slow speeds under nonrepeatable conditions, such as with vehicle testing. Because of this limitation, A&amp;D Company, Limited has developed a tire-testing machine called the dynamic contact force testing rig (DCFR) to measure the dynamic force distribution at the contact patch during high speeds and under reproducible conditions. Preliminary studies have shown that minute changes in shear stress and pressure distribution can be measured consistently. This study observes the dynamic force distribution in a high-performance tire under a variety of test conditions: varying normal load, speed, slip angle, and slip ratio. The tire tread was altered manually by siping additional longitudinal and lateral slits in the existing tread pattern. The tests were repeated for each tread pattern: stock tire tread, additional longitudinal slits, and additional lateral slits. The change in force distribution was compared along the longitudinal, lateral, and vertical axes. The results showed how small changes in tread design can influence tire performance. This article is a preliminary study, primarily investigating the capabilities of the DCFR while investigating basic observable trends in force distribution.

Quantitative Study on the Contact Force and Force Chain Characteristics of Ore Particle Systems during Ore Drawing from a Single Drawpoint under the Influence of a Flexible Barrier

It is of great significance to carry out quantitative research on the contact force chain characteristics of ore particle systems during ore drawing to reveal the microscopic and mesoscopic characteristics of ore particle systems during implementation of the synchronous filling shrinkage stoping method. Based on the particle discrete element method, combined with the relevant knowledge of contact mechanics and statistical mechanics, microscopic properties of the ore particle system were studied quantitatively. (1) The probability distributions of the normal and tangential contact forces during ore drawing from a single drawpoint under a flexible barrier are similar, and both show exponential decay. (2) In the regions on both sides of the model, the ore particles will not be released because they are far from the drawpoint; there, the coordination number is stable, and the density of contact network is large. In the upper part of the drawpoint, ore particles flow, the coordination number fluctuates violently, and the density of contact network is small. (3) In the initial stage, the stress distribution of the ore particle system is uniform, and the strong force chain does not show obvious directivity. After that, the directions of the strong force chains in the ore particle system are inclined to the vertical direction, and the strong force chains mainly bear the load in the vertical direction. (4) In the initial stage of drawing, the normal contact force is mainly concentrated in the vertical direction. With the progression of drawing, the normal contact force at an angle of 30° to the horizontal direction increases gradually, and the number of the main direction of the average contact force distribution changes from one to three (the vertical direction and the direction with a ±30° angle to the horizontal direction).

A Pilot Study on Using Forcemyography to Record Upper-limb Movements for Human-machine Interactive Control.

Forcemyography (FMG) is a useful method to record real-time body motions, which has application potentials for human-machine interactive control. The FMG registers the change of force distribution in the normal direction on muscle surface during limb movements, and the body motions can be recognized by decoding the FMG patterns. In this study, we used FMG to record upper-limb movements and evaluated the influence of different configurations of signal channel and feature on motion classification performances. A four-channel wearable FMG acquisition system was developed to record seven upper-limb movements on each of six able-bodied subjects. The preliminary results showed that the signal channel number has significant influence on motion classification performance; however, the influence of signal feature number on motion classification was insignificant. In addition, the influence of channel combination and feature combination were also discussed in this paper. This work would support the application potential of FMG for body motion recording and may provide useful instructions for the application of FMG in human-machine interactive control.

Unusual Presentations of Focal Periphyseal Edema Zones: A Report of Bilateral Symmetric Presentation and Partial Physeal Closure.

Focal periphyseal edema (FOPE) zones are areas of periphyseal edema seen near the time of physeal closure which are believed to be a physiologic phenomenon related to changes in distribution of forces around the physis as it closes. Since the original case series describing these areas of periphyseal edema, there has been little published in regard to FOPE zone outside of review articles. We present a set of three patients identified with focal periphyseal edema zones around the knee and compare our findings with the initial case series. We include a patient presenting with bilateral, nearly symmetric, focal periphyseal edema zones of the proximal tibia physis and a patient with partial closure of the physis at time of presentation, which were not reported in the original case series.

Influence of calcaneus angle and muscle forces on strain distribution in the human Achilles tendon

BackgroundHeterogeneous distribution of tendon strain is considered to contribute to the development of the Achilles tendon overuse injuries. Force distribution between the three portions of the triceps surae muscle and position of the calcaneus might affect the extent of strain differences within the Achilles tendon. Purpose of this study was to determine the effect of changes in force distribution within the triceps muscle and changes in calcaneus position on intratendinous strain distribution of the Achilles tendon. MethodsFive cadaveric Achilles tendons including complete triceps surae and calcaneus were dissected. Specimens were mounted in a loading simulator allowing independent force application for the three parts of triceps muscle and changes calcaneus eversion and inversion position. Strain was determined in different aspects of the Achilles tendon. FindingsChanges of calcaneus position resulted in intratendinous strain differences up to 15%, changes in force distribution within the triceps muscle resulted in strain differences up to 2.5%. Calcaneal eversion was connected to a higher degree of strain in medial tendon portions, while inversion increased strain in lateral tendon portions. InterpretationMedio-lateral, proximo-distal and dorsal–ventral distribution of tendon strain is rather influenced by kinematics of the subtalar joint than by muscular imbalances within the triceps muscle. Clinical movement analyses should focus on motion pattern combining rearfoot eversion with high Achilles tendon load. The results indicate that twist of the Achilles tendon fascicles seems of paramount importance in balancing tendon strain. To get more insight into the Achilles tendon injuries pathogenesis future research should focus on methods monitoring heterogeneous distribution of strain in vivo.

Dynamic simulation of granular packing of fine cohesive particles with different size distributions

A granular packing of fine cohesive particles with three different size distributions (monosize, bimodal and Gaussian) was studied using the Distinct Element Method (DEM). The dissipative forces including viscoelastic and frictional contact forces between the colliding particles cause the energy loss during the packing process, and finally the particles agglomerations is formed. The conservative forces of gravitation and van der Waals forces are also included in the simulations. For the cases of monosized particles packing, the packing structure becomes looser when the particle size becomes smaller. When the particle diameter is less than 100 μm, the type of contact of edge-sharing in-plane equilateral triangle is not dominant in the packing structure. As to the bimodal situations, the change of the particle population ratio does not have much influence on the compactness of the packing structure in the case of small particle size ratio. However, in the cases of large particle size ratio, it is observed that the particle population ratio does affect packing structure compactness. When the smaller particle population ratio increases the packing structure becomes more compact. Regarding the packing of particles with Gaussian distribution, the packing structure becomes more compact as the mean diameter increases. On the other hand, as the particle diameter deviation increases, the packing structure becomes looser. The radial distribution function and force distribution are also analyzed for different packing cases. It is found that the distributed range of contact force is larger than that of van der Waals force in the final granular matters, and the force distribution changes as the particle size distribution changes.

Radial force distribution changes associated with tangential force production in cylindrical grasping, and the importance of anatomical registration

Radial force (Fr) distributions describe grip force coordination about a cylindrical object. Recent studies have employed only explicit Fr tasks, and have not normalized for anatomical variance when considering Fr distributions. The goals of the present study were (i) to explore Fr during tangential force production tasks, and (ii) to examine the extent to which anatomical registration (i.e. spatial normalization of anatomically analogous structures) could improve signal detectability in Fr data. Twelve subjects grasped a vertically oriented cylindrical handle (diameter=6cm) and matched target upward tangential forces of 10, 20, and 30N. Fr data were measured using a flexible pressure mat with an angular resolution of 4.8°, and were registered using piecewise-linear interpolation between five manually identified points-of-interest. Results indicate that Fr was primarily limited to three contact regions: the distal thumb, the distal fingers, and the fingers’ metatacarpal heads, and that, while increases in tangential force caused significant increases in Fr for these regions, they did not significantly affect the Fr distribution across the hand. Registration was found to substantially reduce between-subject variability, as indicated by both accentuated Fr trends, and amplification of the test statistic. These results imply that, while subjects focus Fr primarily on three anatomical regions during cylindrical grasp, inter-subject anatomical differences introduce a variability that, if not corrected for via registration, may compromise one's ability to draw anatomically relevant conclusions from grasping force data.

Flat boundaries and their effect on sand testing

AbstractA study of the effect of the use of flat boundaries on the stressing of a sample of an idealized granular material with no applied shear is presented. Discrete element method (DEM) data of 1D compression were analysed and the local strain field inside the sample was investigated as the sample was stressed. A best‐fit strain was seen to best describe the material behaviour free from boundary effects. The individual particle displacements were probed, providing insight into the behaviour of particles adjacent to the boundaries. In addition, the porosity and force distribution inside the sample were observed, allowing for estimates of the width of a boundary region to be made. This region, non‐representative of far‐field material behaviour, will affect the behaviour of a granular sample in DEM or laboratory tests, with local porosity differences leading to a change in the transport properties of the sample, and force distribution changes leading to a bias in the location of grain cracking or crushing events for sufficiently high stress levels. Nevertheless, the largest effect of the boundary region was a severe underestimation of the stiffness of a granular material. Copyright © 2009 John Wiley &amp; Sons, Ltd.

Task-specific modulation of multi-digit forces to object texture

During multi-digit grasping both local and non-local digit force responses occur in response to changes in texture at selected digits depending on the grasp configuration. However, the extent to which the specific patterns of force distribution depend on the requirement to hold the object against gravity remains to be determined. In the present study, we examined whether grasp force sharing patterns are invariant when the constraint of maintaining the object orientation vertical against gravity is removed. We used changes in object texture to elicit force changes at single digits during two grasping tasks with different behavioral contexts. One task entailed holding an object against gravity (object hold [OH]). A second (force production [FP]) task consisted of generating lifting forces on an object clamped to the tabletop that were matched to those used during OH. Unlike OH, the FP task lacks the behavioral consequences associated with erroneous sharing of normal and tangential digit forces, e.g., object tilt. Ten subjects lifted and simulated lifting an instrumented object measuring grasping normal and vertical tangential forces at all five digits when the textures were uniformly high-friction sandpaper or low-friction rayon and when one digit contacted a different frictional texture than the other four digits. We found that in both tasks texture changes at individual digits elicited force changes at that digit as well as other digits. However, the specific pattern of force distribution changes differed during OH compared to FP. While subjects modulate the normal and tangential digit forces to different degrees depending on object texture and the grasping task, they ignore the requirement of moment equilibrium when this has no consequences on object orientation (FP task). These findings indicate that multi-digit force responses to texture revealed by previous studies are not obligatory and suggest that the behavioral context of a task should be considered when inferring general principles of multi-digit force coordination.

Occlusion: Supporting and Pacing Force Distribution

One of the prominent roles of the occlusion would be to support the force balance wobbling in stomatognathic system, thus pacing and minimizing the change of force distribution with age. Patient's demands on the prosthetic treatment have been becoming higher and more complicated during the past several decades. These demands include not only the precise restoration of the decayed tooth but also the treatment to provide stable and comfortable state of the stomatognathic system in the longer term. These demands would deeply be related to ; 1) How to finalize the information on temporary or treatment prosthesis, which has the resulted shape of the precise functional adjustment, on the final prosthesis, and 2) How to cope with the persistent complaints regarding tooth, tongue and other related sensations. In these aspects, patient's subjectivity and/or esthesis might need to be satisfied with the form and/or function of the resulted prosthesis. The clinical difficulties might be related to the following two points, which are 1) the accuracy of the reproduction procedure from the treatment prosthesis to the final one and 2) stability of the mandibular position or the condylar position which support the functional basis for the prosthesis. In order to cope with the complicated requirements, we have been using double-casting method for providing cast restorations. This is a method to produce a cast restoration in two functional parts. The first casting step consists of a base-crown which covers the abutment tooth and adjacent proximal contact point(s). The second step is the molding of the functionally required occlusal form onto the base-crown. The third step is the metal casting onto the base-crown replacing the molded portion. This method could be applied in various situations where we are forced to match the function and the form. The purpose of this paper is to provide a good orientation to the double-casting method and also to discuss the concept that might pace and minimize the change of force distribution in stomatognathic system.

Contact forces at the sliding interface: Mixed versus pure model alkane monolayers

Classical molecular dynamics simulations of an amorphous carbon tip sliding against monolayers of n-alkane chains are presented. The tribological behavior of tightly packed, pure monolayers composed of chains containing 14 carbon atoms is compared to mixed monolayers that randomly combine equal amounts of 12- and 16-carbon-atom chains. When sliding in the direction of chain cant under repulsive (positive) loads, pure monolayers consistently show lower friction than mixed monolayers. The distribution of contact forces between individual monolayer chain groups and the tip shows pure and mixed monolayers resist tip motion similarly. In contrast, the contact forces "pushing" the tip along differ in the two monolayers. The pure monolayers exhibit a high level of symmetry between resisting and pushing forces which results in a lower net friction. Both systems exhibit a marked friction anisotropy. The contact force distribution changes dramatically as a result of the change in sliding direction, resulting in an increase in friction. Upon continued sliding in the direction perpendicular to chain cant, both types of monolayers are often capable of transitioning to a state where the chains are primarily oriented with the cant along the sliding direction. A large change in the distribution of contact forces and a reduction in friction accompany this transition.

Tissue Oxygenation and EMG during Computer Mouse Work and Submaximal Isometric Wrist Extensions

Sufficient tissue oxygenation (TO2) is essential for muscle function in general. However, it is not known to which extent TO2 is influenced during different low-level contractions. The aim was to study the interaction between EMG activity and TO2 during computer mouse tasks and submaximal isometric contractions at load levels corresponding to levels that occur during repetitive work in industry. Eight healthy subjects performed multidirectional computer mouse tasks (40 and 60 clicks/min) with the right arm. In addition, 1 -minute isometric wrist extensions at 5, 15 and 25 %Maximal Voluntary Contraction (MVC) were performed. Further, a 15 %MVC wrist extension until exhaustion was performed. Near-infrared spectroscopy was used to measure TO2 of m. extensor carpi radialis. EMG was recorded from m. extensor carpi radialis and m. extensor digitorum. During mousing the EMGRMS activity was in generel higher during the high speed compared to the low speed task. Muscular load of the forearm has isometric characteristics to a high degree. No significant difference in TO2 was found between the two mousing speeds. During the isometric contractions EMGRMS increased and TO2 decreased with increasing contraction level. The mean endurance time at the 15 %MVC wrist extension was 22.6 min. The average exerted force remained constant though fluctuations in the force increased as a function of time, indicating impaired force control due to development of fatigue. During the endurance task the EMGRMS activity increased and the EMGMPF decreased, indicating electromyographic signs of muscle fatigue. Within less than one minute TO2 decreased significantly relative to resting values. No further decrease was seen during the endurance contraction. Point of exhaustion was not related either to a gradual or a sudden decrease in TO2. Although the average exerted force remained constant, sudden changes in EMGRMS was seen in some subjects especially in the last part of the contraction, indicating changes in force distribution between muscles. This is assumed to be a fatigue-preventing mechanism. These changes in extensor carpi radialis muscle activity were reflected as opposite changes in TO2-levels, A cross correlation analysis showed a correlation between in extensor carpi radialis muscle activity and TO2, time displacement=3.4 sec, r=−0.31. This indicates that the changes in EMG activity precede the changes in TO2-level. In conclusion, TO2 was inversely related to muscle activity and exerted force. A steady state level below resting level of TO2 was found during the prolonged fatiguing isometric contraction. Point of exhaustion could not be explained either by a gradual or a sudden decrease in TO2.

A tensegrity model of the cytoskeleton in spread and round cells.

Measurements on adherent cells have shown that spreading affects their mechanics. Highly spread cells are stiffer than less spread cells. The stiffness increases approximately linearly with increasing applied stress and more so in highly spread cells than in less spread cells. In this study, a six-strut tensegrity model of the cytoskeleton is used to analyze the effect of spreading on cellular mechanics. Two configurations are considered: a "round" configuration where a spherically shaped model is anchored to a flat rigid surface at three joints, and a "spread" configuration, where three additional joints of the model are attached to the surface. In both configurations a pulling force is applied at a free joint, distal from the anchoring surface, and the corresponding deformation is determined from equations of equilibrium. The model stiffness is obtained as the ratio of applied force to deformation. It is found that the stiffness changes with spreading consistently with the observations in cells. These findings suggest the possibility that the spreading-induced changes of the mechanical properties of the cell are the result of the concomitant changes in force distribution and microstructural geometry of the cytoskeleton.