scholarly journals Kinematics and control of frog hindlimb movements

1991 ◽  
Vol 65 (3) ◽  
pp. 547-562 ◽  
Author(s):  
D. J. Ostry ◽  
A. G. Feldman ◽  
J. R. Flanagan
Keyword(s):  
Nervous System ◽  
High Speed ◽  
Imaging System ◽  
Maximum Velocity ◽  
Joint Space ◽  
Motion Path ◽  
Three Dimension ◽  
Joint Angles ◽  
Joint Configuration ◽  
Straight Line

1. The determinants of the motion path of the hindlimb were explored in both intact and spinal frogs. In the spinal preparations the kinematic properties of withdrawal and crossed-extension reflexes were studied. In the intact frog the kinematics of withdrawal and swimming movements were examined. Frog hindlimb paths were described in joint angle (intrinsic) coordinates rather than limb endpoint (extrinsic) coordinates. 2. To study withdrawal and crossed-extension reflexes, the initial angles at the hip, knee, and ankle were varied. Withdrawal and crossed extension were recorded in three dimension (3-D) with the use of an infra-red spatial imaging system. Swimming movements against currents of different speeds were obtained with high-speed film. 3. Three strategies were considered related to the form of the hypothesized equilibrium paths specified by the nervous system: all trajectories lie on a single line in angular coordinates; all trajectories are directed toward a common final position; and all trajectories have the same direction independent of initial joint configuration. 4. Joint space paths in withdrawal were found to be straight and parallel independent of the initial joint configuration. The hip and knee were found to start simultaneously and in 75% of the conditions tested to reach maximum velocity simultaneously. Hip-knee maximum velocity ratios were similar in magnitude over differences in initial joint angles. This is consistent with the observation of parallel paths and supports the view that the nervous system specifies a single direction for equilibrium trajectories. 5. Straight line paths with slopes similar to those observed in withdrawal in the spinal preparation were found in swimming movements in the intact frog. Straight line paths in joint space are consistent with the idea that swimming and withdrawal are organized and controlled in a joint-level coordinate system. The similarities observed between spinal and intact preparations suggest that a common set of constructive elements underlies these behaviors. 6. Path curvature was introduced when joint limits were approached toward the end of the movement. Depending on the initial joint angles, the joint movements ended at different times. When initial joint angles were unequal, joints moving from smaller initial angles reached their functional limits earlier and stopped first. 7. In withdrawal and crossed extension in the spinal frog, velocity profiles at a given joint were similar over the initial portion of the curve for movements of different amplitude. This is consistent with the idea that withdrawal and crossed-extension movements of different amplitude are produced by a constant rate of shift of the equilibrium position.

Stereotypical Fingertip Trajectories During Grasp

2003 ◽  
Vol 90 (6) ◽  
pp. 3702-3710 ◽  
Author(s):  
D. G. Kamper ◽  
E. G. Cruz ◽  
M. P. Siegel
Keyword(s):  
Logarithmic Spiral ◽  
Joint Space ◽  
Joint Angles ◽  
Object Type ◽  
Cartesian Space ◽  
Reach And Grasp ◽  
Straight Line ◽  
Hand Impairment ◽  
Finger Posture ◽  
Specific Part

The kinematics of movement of all five digits was analyzed during reach-and-grasp tasks for a variety of objects. Ten healthy subjects performed 20 trials involving the grasp of five objects of distinct size and shape. Joint angles were recorded, and digit trajectories were computed using forward kinematics. For a given subject, fingertip trajectories were consistent across trials. The different-sized objects largely produced movement along different portions of a stereotypical trajectory described by a logarithmic spiral. The spirals fit the actual finger positions with a mean error across all trials of 0.23 ± 0.25 cm and accounted for over 98% of the variance in finger position. These patterns were consistent independent of initial finger posture. Subjects did not produce straight-line movements, either in Cartesian space or joint space. The direction of the thumb trajectories exhibited a greater dependence on object type than the finger trajectories, but still utilized a small percentage (<5%) of the available workspace. These results suggest that restoration of a small but specific part of the workspace could have significant impact on function following hand impairment.

In Vivo Bone Motion From High Frame Rate Stereo Radiography

2003 ◽  
Author(s):  
William J. Anderst ◽  
Scott Tashman
Keyword(s):  
Subchondral Bone ◽  
High Speed ◽  
Imaging System ◽  
Close Contact ◽  
Cruciate Ligament ◽  
Joint Space ◽  
Frame Rate ◽  
Bone Surface ◽  
Post Surgery ◽  
Ct Slices

This paper presents a method to calculate functional joint space during dynamic movement. This method combines high-speed biplane radiographic image data and three-dimensional (3D) bone surface data obtained from computed tomography (CT). Subjects were patients undergoing anterior cruciate ligament (ACL) reconstructive surgery. Three tantalum beads were implanted bilaterally into both the femur and tibia during surgery. CT scans were performed after bead implantation, and the CT slices were reconstructed into 3D solid figures, with the implanted beads identifiable within the stack of CT slices. Subjects were tested 6,12 and 24 months post surgery. Testing activities included downhill running on a treadmill and one-legged hopping onto a force plate. During testing, the stereo-radiographic imaging system collected images at 250 frames per second. Later, the implanted beads were identified in the x-ray images and tracked in 3D with an accuracy of 0.10 mm. The 3D bead location data were used to position the reconstructed solid bone figures in 3D space. In this way, the location of each bone surface was determined each instant. This method can be used to identify the regions of close contact between bones during dynamic motion, to calculate the surface area of subchondral bone within close contact, and to determine the changing position of the close contact area during dynamic activities. Using these techniques, comparisons can be made between subchondral bone motion in healthy and reconstructed joints and changes in dynamic joint space can be measured over time.

scholarly journals Dance motion capture and composition using multiple RGB and depth sensors

2017 ◽  
Vol 13 (2) ◽  
pp. 155014771769608 ◽  
Author(s):  
Yejin Kim
Keyword(s):  
Motion Capture ◽  
High Speed ◽  
Motion Path ◽  
High Complexity ◽  
Motion Data ◽  
Depth Sensors ◽  
Motion Editing ◽  
Human Movements ◽  
Marker Free ◽  
Motion Search

Dynamic human movements such as dance are difficult to capture without using external markers due to the high complexity of a dancer’s body. This article introduces a marker-free motion capture and composition system for dance motion that uses multiple RGB and depth sensors. Our motion capture system utilizes a set of high-speed RGB and depth sensors to generate skeletal motion data from an expert dancer. During the motion acquisition process, a skeleton tracking method based on a particle filter is provided to estimate the motion parameters for each frame from a sequence of color images and depth features retrieved from the sensors. The expert motion data become archived in a database. The authoring methods in our composition system automate most of the motion editing processes for general users by providing an online motion search with an input posture and then performing motion synthesis on an arbitrary motion path. Using the proposed system, we demonstrate that various dance performances can be composed in an intuitive and efficient way on client devices such as tablets and kiosk PCs.

Betadine has a ciliotoxic effect on ciliated human respiratory cells

2014 ◽  
Vol 129 (S1) ◽  
pp. S45-S50 ◽  
Author(s):  
J H Kim ◽  
J Rimmer ◽  
N Mrad ◽  
S Ahmadzada ◽  
R J Harvey
Keyword(s):  
Epithelial Cells ◽  
High Speed ◽  
Imaging System ◽  
Beat Frequency ◽  
Ciliary Beat Frequency ◽  
Positive Control ◽  
Clinical Dose ◽  
Significant Difference ◽  
Sinonasal Mucosa ◽  
Ciliary Beat

AbstractObjective:This study investigated the effect of Betadine on ciliated human respiratory epithelial cells.Methods:Epithelial cells from human sinonasal mucosa were cultured at the air–liquid interface. The cultures were tested with Hanks' balanced salt solution containing 10 mM HEPES (control), 100 µM ATP (positive control), 5 per cent Betadine or 10 per cent Betadine (clinical dose). Ciliary beat frequency was analysed using a high-speed camera on a computer imaging system.Results:Undiluted 10 per cent Betadine (n = 6) decreased the proportion of actively beating cilia over 1 minute (p < 0.01). Ciliary beat frequency decreased from 11.15 ± 4.64 Hz to no detectable activity. The result was similar with 5 per cent Betadine (n = 7), with no significant difference compared with the 10 per cent solution findings.Conclusion:Betadine, at either 5 and 10 per cent, was ciliotoxic. Caution should be applied to the use of topical Betadine solution on the respiratory mucosal surface.

Kinematics of Tongue Projection in Chamaeleo Oustaleti

1991 ◽  
Vol 159 (1) ◽  
pp. 109-133 ◽  
Author(s):  
PETER C. WAINWRIGHT ◽  
DAVID M. KRAKLAU ◽  
ALBERT F. BENNETT
Keyword(s):  
High Speed ◽  
Prey Capture ◽  
Maximum Velocity ◽  
Head Movements ◽  
Florida State University ◽  
State University ◽  
Maximum Acceleration ◽  
Related Family ◽  
High Speed Cinematography ◽  
Tongue Movements

The kinematics of prey capture by the chamaeleonid lizard Chamaeleo oustaleti were studied using high-speed cinematography. Three feeding sequences from each of two individuals were analyzed for strike distances of 20 and 35 cm, at 30°C. Ten distances and angles were measured from sequential frames beginning approximately 0.5 s prior to tongue projection and continuing for about 1.0 s. Sixteen additional variables, documenting maximum excursions and the timing of events, were calculated from the kinematic profiles. Quantified descriptions of head, hyoid and tongue movements are presented. Previously unrecognized rapid protraction of the hyobranchial skeleton simultaneously with the onset of tongue projection was documented and it is proposed that this assists the accelerator muscle in powering tongue projection. Acceleration of the tongue occurred in about 20ms, reaching a maximum acceleration of 486 m s−2 and maximum velocity of 5.8m s−1 in 35 cm strikes. Deceleration of the tongue usually began within 5 ms before prey contract and the direction of tongue movement was reversed within 10 ms of prey contact. Retraction of the tongue, caused by shortening of the retractor muscles, reached a maximum velocity of 2.99 ms−1 and was complete 330 ms after prey contact. Projection distance influences many aspects of prey capture kinematics, particularly projection time, tongue retraction time and the extent of gape and head movements during tongue retraction, all of which are smaller in shorter feedings. Though several features of the chameleon strike have apparently been retained from lizards not capable of ballistic tongue projection, key differences are documented. Unlike members of a related family, the Agamidae, C. oustaleti uses no body lunge during prey capture, exhibits gape reduction during tongue projection and strongly depresses the head and jaws during tongue retraction. Note: Present address: Department of Biological Sciences, Florida State University, Tallahassee, FL 32306, USA.

Sliding Dynamics of a Water Droplet On Silicon Oil Film Surface

2021 ◽  
Author(s):  
Bekir Sami Yilbas ◽  
Anwaruddin Siddiqui Mohammed ◽  
Abba Abdulhamid Abubakar ◽  
Saeed Bahatab ◽  
Hussain Al-Qahtani ◽  
...  
Keyword(s):  
Water Droplet ◽  
High Speed ◽  
Film Surface ◽  
Maximum Velocity ◽  
Optical Transmittance ◽  
Gravitational Energy ◽  
Droplet Motion ◽  
Droplet Dynamics ◽  
Oil Film ◽  
Silicon Oil

Abstract A sliding droplet over the silicon oil film is examined and the dynamics of droplet motion are explored. The solution crystallized wafer surfaces are silicon oil impregnated and the uniform thickness oil film is realized. A recording facility operating at high-speed and the tracker program are used to monitor and evaluate the droplet dynamics during droplet sliding. The sliding behavior and flow generated in the droplet fluid are predicted by adopting the experimental terms. Findings revealed that the crystallized surface possesses the texture composing of spherules and fibrils, which give rise to 132o ± 4o contact angle and 38o ± 4o hysteresis. Oil impregnation on the crystalized surface improves the optical transmittance by three times for 250 nm to 500 nm wavelength range and almost 1.5 times after 500 nm to 850 nm wavelengths of the optical spectrum. The oil rim and ridges are developed in sliding water droplet vicinity while influencing droplet motion; however, this influence is estimated as almost 12% of droplet gravitational energy change during sliding. A circulatory flow is developed inside the droplet fluid and the maximum velocity in the droplet fluid changes as the droplet location changes on the oil surface during its sliding.

Comparison of the fast-start performances of closely related, morphologically distinct threespine sticklebacks (Gasterosteus spp.)

1996 ◽  
Vol 199 (12) ◽  
pp. 2595-2604 ◽  
Author(s):  
T Law ◽  
R Blake
Keyword(s):  
Angular Velocity ◽  
High Speed ◽  
High Performance ◽  
Gasterosteus Aculeatus ◽  
Morphological Characteristics ◽  
Maximum Velocity ◽  
Threespine Stickleback ◽  
Biomechanical Study ◽  
Maximum Acceleration ◽  
Fast Start

Fast-start escape performances for two species of threespine stickleback, Gasterosteus spp., were investigated using high-speed cinematography (400 Hz). The two fishes (not yet formally described, referred to here as benthic and limnetic) inhabit different niches within Paxton Lake, British Columbia, Canada, and are recent, morphologically distinct species. All escape responses observed for both species were double-bend C-type fast-starts. There were no significant differences between the species for any linear or angular parameter (pooled averages, both species: duration 0.048 s, distance 0.033 m, maximum velocity 1.10 m s-1, maximum acceleration 137 m s-2, maximum horizontal angular velocity 473.6 rad s-1 and maximum overall angular velocity 511.1 rad s-1). Benthics and limnetics have the greatest added mass (Ma) at 0.3 and 0.6 body lengths, respectively. The maximum Ma does not include the fins for benthics, but for limnetics the dorsal and anal fins contribute greatly to the maximum Ma. The deep, posteriorly placed fins of limnetics enable them to have a fast-start performance equivalent to that of the deeper-bodied benthics. Both the limnetic and benthic fishes have significantly higher escape fast-start velocities than their ancestral form, the anadromous threespine stickleback Gasterosteus aculeatus, suggesting that the high performance of the Paxton Lake sticklebacks is an evolutionarily derived trait. In this biomechanical study of functional morphology, we demonstrate that similar high fast-start performance can be achieved by different suites of morphological characteristics and suggest that predation might be the selective force for the high escape performance in these two fishes.

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