The Hydraulic Mechanism of the Predatory Strike in Dragonfly Larvae

1980 ◽  
Vol 88 (1) ◽  
pp. 1-20 ◽  
Author(s):  
YOSHITAKA TANAKA ◽  
MITUHIKO HISADA
Keyword(s):  
High Speed ◽  
Late Phase ◽  
Angular Acceleration ◽  
The Body ◽  
Extensor Muscles ◽  
Flexor Muscles ◽  
Electrophysiological Measurements ◽  
Hydraulic Mechanism ◽  
Great Acceleration ◽  
Internal Body

1. Aeschna larvae catch prey with a fast-moving elongated labium. The mechanism of this movement was analysed by high-speed cinematographs and by hydrostatic and electrophysiological measurements. 2. The strike movement consists of an initial, mid and late phase. The angular acceleration of the joints of the labium is 2·6 × 105 and 7·8 × 105 deg·s−2 during the initial and mid phase respectively. The torque necessary for the acceleration was calculated to be 1·3 × 10−5 and 4·0 × 10−5 N.m for the initial and mid-phases respectively. 3. The relation between the pressure applied to the labium and the extension torque at the joints has been established. No torque develops about the postmentum-prementum joint as long as the click of the flexed labium is engaged. 4. The power production of the extensor muscles is less than the power output of the mid phase. The power for the mid phase is derived from the internal body pressure developed by the contraction of the abdominal dorsoventral muscles. The required pressure for the mid phase is about 60 cmH2O if the resistance is neglected and 80 cmH2O when the resistance is considered. 5. Abdominal dorso-ventral muscles contract 110–500 ms before the onset of the strike and the body pressure of the animal increases to a peak of 40–120 cmH2O at the onset of the strike. 6. The geometry of the labial joints gives the primary flexor muscles of the labium a large mechanical advantage over the extensor muscles in the fully flexed labium, and allows the extensor muscles to contract almost isometrically. 7. The extensor muscles and the primary flexor muscles co-contract for 75–100 ms before the strike. The strike movement begins when the flexor muscles relax. The stored energy in the extensor system is released suddenly and disengages the click producing the initial phase. Once the click is disengaged the internal pressure produces the large torque to move the labium with great acceleration during the mid phase.

scholarly journals Operation of the alula as an indicator of gear change in hoverflies

2011 ◽  
Vol 9 (71) ◽  
pp. 1194-1207 ◽  
Author(s):  
Simon M. Walker ◽  
Adrian L. R. Thomas ◽  
Graham K. Taylor
Keyword(s):  
High Speed ◽  
Aerodynamic Force ◽  
Angular Acceleration ◽  
The State ◽  
The Body ◽  
Kinematic Parameters ◽  
Wing Kinematics ◽  
Change Mechanism ◽  
The Third ◽  
Gear Change

The alula is a hinged flap found at the base of the wings of most brachyceran Diptera. The alula accounts for up to 10 per cent of the total wing area in hoverflies (Syrphidae), and its hinged arrangement allows the wings to be swept back over the thorax and abdomen at rest. The alula is actuated via the third axillary sclerite, which is a component of the wing hinge that is involved in wing retraction and control. The third axillary sclerite has also been implicated in the gear change mechanism of flies. This mechanism allows rapid switching between different modes of wing kinematics, by imposing or removing contact with a mechanical stop limiting movement of the wing during the lower half of the downstroke. The alula operates in two distinct states during flight—flipped or flat—and we hypothesize that its state indicates switching between different flight modes. We used high-speed digital video of free-flying hoverflies ( Eristalis tenax and Eristalis pertinax ) to investigate whether flipping of the alula was associated with changes in wing and body kinematics. We found that alula state was associated with different distributions of multiple wing kinematic parameters, including stroke amplitude, stroke deviation angle, downstroke angle of incidence and timing of supination. Changes in all of these parameters have previously been linked to gear change in flies. Symmetric flipping of the alulae was associated with changes in the symmetric linear acceleration of the body, while asymmetric flipping of the alulae was associated with asymmetric angular acceleration of the body. We conclude that the wings produce less aerodynamic force when the alula is flipped, largely as a result of the accompanying changes in wing kinematics. The alula changes state at mid-downstroke, which is the point at which the gear change mechanism is known to come into effect. This transition is accompanied by changes in the other wing kinematic parameters. We therefore find that the state of the alula is linked to the same parameters as are affected by the gear change mechanism. We conclude that the state of the alula does indeed indicate the operation of different flight modes in Eristalis , and infer that a likely mechanism for these changes in flight mode is the gear change mechanism.

Unexpected motor patterns for hindlimb muscles during slope walking in the cat

1995 ◽  
Vol 74 (5) ◽  
pp. 2211-2215 ◽  
Author(s):  
J. L. Smith ◽  
P. Carlson-Kuhta
Keyword(s):  
High Speed ◽  
Stance Phase ◽  
Vastus Lateralis ◽  
Activity Patterns ◽  
Biceps Femoris ◽  
Related Activity ◽  
Motor Patterns ◽  
Extensor Muscles ◽  
Flexor Muscles ◽  
External Forces

1. Hindlimb kinematics and motor patterns were assessed from high-speed cine film synchronized with electromyographic (EMG) data from cats trained to walk on a walkway placed at four grades (25, 50, 75, and 100%). 2. Flexor muscles of the hip (iliopsoas) and ankle (tibialis anterior) had similar activity patterns for the swing phase of up- and down-slope walking; both flexor muscles also had stance-related activity during down-slope walking and this was unexpected. Extensor muscles of the hip (anterior biceps femoris and anterior semimembranosus), knee [vastus lateralis (VL)], and ankle [lateral gastrocnemius (LG)] were active during the stance phase of up-slope walking. The VL and LG activity was reduced in duration during stance of down-slope walking and centered around paw contact. Hip extensors, however, were totally inactive during stance of down-slope walking, and this was not expected. 3. Flexor muscles at the hip and ankle (not extensor muscles) dominated the stance phase of down-slope walking, especially at the steeper slopes. This switch in motor patterns may be required to counterbalance external forces that produced extension at the hip and ankle joints during the stance phase of down-slope walking. Neural mechanisms for programming stance-related activity of flexor muscles are discussed.

Phase-dependent responses evoked in limb muscles by stimulation of medullary reticular formation during locomotion in thalamic cats

1984 ◽  
Vol 52 (4) ◽  
pp. 653-675 ◽  
Author(s):  
T. Drew ◽  
S. Rossignol
Keyword(s):  
Reticular Formation ◽  
The Body ◽  
The Other ◽  
Step Cycle ◽  
Medullary Reticular Formation ◽  
Locomotor Rhythm ◽  
Extensor Muscles ◽  
Short Period ◽  
Flexor Muscles ◽  
Excitatory Responses

Electromyographic and kinematic responses of all four limbs were studied when loci within the medullary reticular formation (MRF) were stimulated (30-ms train of 0.2-ms pulses at 300 Hz, strength 35 microA) during treadmill locomotion in spontaneously walking thalamic cats. Responses could be evoked in flexor or extensor muscles of any given limb by such stimulation, depending on the time during the step cycle at which the stimulus was delivered. Stimulation normally excited flexor muscles but could either excite or inhibit extensor muscles depending on the exact position of the electrode. Excitatory responses in extensor muscles were often followed by a short period of inhibition of activity. The responses in muscles of the opposing limbs of the same girdle were, in general, reciprocally organized. For instance, a stimulus delivered during the swing phase of the ipsilateral limb normally evoked excitatory responses both in flexor muscles of that limb and in extensor muscles of the contralateral limb. The same stimulus delivered during the stance phase of the ipsilateral limb evoked excitatory responses in ipsilateral extensor muscles and in contralateral flexor muscles. Responses were also observed at the same time in fore- and hindlimbs that were well organized with respect to the locomotor cycle. Seventy-five percent of all responses occurred within 8-20 ms of the onset of the stimulus train. Responses evoked in muscles of the opposing limbs of one girdle (e.g., a flexor of one limb and an extensor of the other) had similar latencies, suggesting that the responses were synchronously organized on both sides of the body rather than one being a consequence of the other. Although the majority of responses in a given muscle were elicited during its period of activity, responses could occasionally be evoked when there was no activity in that muscle or could be absent despite activity in the muscle. The short trains of stimuli were normally potent enough to affect the limb trajectory, which reflected changes in the onset or the offset of the activity of most muscles. Thus the stimuli effectively changed both the duration of the period of activity in these muscles and the overall step cycle. Longer trains of stimuli (200 ms) markedly amplified these changes to the point of completely resetting the locomotor rhythm.(ABSTRACT TRUNCATED AT 400 WORDS)

The Comparative Analysis on Muscles of Short and Long Track Speed Skating Athletes

2011 ◽  
Vol 117-119 ◽  
pp. 737-740
Author(s):  
Jiao Yang Xia
Keyword(s):  
High Speed ◽  
Testing System ◽  
Isokinetic Testing ◽  
Speed Skating ◽  
Extensor Muscles ◽  
Flexor Muscles ◽  
Ankle Muscle ◽  
Left And Right ◽  
Track Athletes ◽  
All Speeds

The knee and ankle muscle strength of excellent male skating athletes is measured and analyzed by Cybex isokinetic testing system. Based on the features of athletes’ muscles strength, the study aims to find if there are differences and shortages between long track and short track speed skating athletes and whether they can learn from each other in the training, then to make the further discussion on the event itself. The main conclusions are as follows: 1. In the index of maximum strength, the torque/BW features of knee and ankle of the short track athletes are more fit the law of skating event, while the long track athletes do good in low speed, but opposite in high speed. The long track skaters need to improve the strength in high speed. 2. In the index of flexor-extensor, both long and short-track are lower than the recommended values, especially the short track. The two groups need to improve the strength of flexor muscles and to keep balance and coordinate of knee muscles. 3. In the index of acceleration, the power values of long track skaters are higher than short track skater’s, except left extensor muscles. The left extensor muscles of long track skaters are lower than their right ones, and should improve the balance of both legs. The short track skaters need to improve the powers of left and right knees in all speeds.

Body Weight: its Relationship to Tissue Composition, Segmental Distribution of Mass, and Motor Function III.* The Didelphidae of French Guyana

1983 ◽  
Vol 31 (3) ◽  
pp. 299 ◽  
Author(s):  
TI Grand
Keyword(s):  
Body Weight ◽  
High Speed ◽  
Alimentary Tract ◽  
The Body ◽  
Muscle Size ◽  
Tissue Composition ◽  
Large Head ◽  
Extensor Muscles ◽  
French Guyana ◽  
Total Muscle

Two sets of anatomical data are presented for six marsupial genera from French Guyana: tissue (skin, muscle, bone) and organ (alimentary tract, brain, eyes) proportions, and segmental distribution of mass (head, tail, thighs, etc.). As a percentage of total weight, skin is about equal in all genera, but the percentage of muscle is low in Caluromys and Didelphis (32%) and exceptionally high in Metachirus (45%); the percentage of viscera is low in Marmosa (6%) and high in Caluromys (10%). Philander, Caluromys, and Marmosa are similar in the segmental distribution of weight: large head, moderately sized thighs, and heavy, prehensile tail. Caluromys and Philander differ in the percentage of total muscle, size of the eyes, and weight of the alimentary tract. Only Monodelphis and Metachirus strongly diverge from the group, and Metachirus possesses many characteristics of high-speed terrestrial cursors such as Dolichotis and Lepus: high percentage of muscle in the body; muscular arms and thighs; elongated and lightened feet; and heavy lumbar extensor muscles. Basically, however, the Didelphidae remain small, prehensile-tailed, scampering and climbing omnivores with only moderate hindlimb dominance. They have not differentiated structurally as much as the prosimians in comparable niches in West Africa or Madagascar. Certain forces have acted conservatively upon body size and locomotor tissues.

Some Special Aspects of Hypersonic Flow Fields

1959 ◽  
Vol 63 (585) ◽  
pp. 508-512 ◽  
Author(s):  
K. W. Mangler
Keyword(s):  
Hypersonic Flow ◽  
High Speed ◽  
Flow Fields ◽  
The Body ◽  
Lower Velocity ◽  
Bow Wave ◽  
Total Head ◽  
Bow Shocks ◽  
Lower Entropy ◽  
Subsonic Region

When a body moves through air at very high speed at such a height that the air can be considered as a continuum, the distinction between sharp and blunt noses with their attached or detached bow shocks loses its significance, since, in practical cases, the bow wave is always detached and fairly strong. In practice, all bodies behave as blunt shapes with a smaller or larger subsonic region near the nose where the entropy and the corresponding loss of total head change from streamline to streamline due to the curvature of the bow shock. These entropy gradients determine the behaviour of the hypersonic flow fields to a large extent. Even in regions where viscosity effects are small they give rise to gradients of the velocity and shear layers with a lower velocity and a higher entropy near the surface than would occur in their absence. Thus one can expect to gain some relief in the heating problems arising on the surface of the body. On the other hand, one would lose farther downstream on long slender shapes as more and more air of lower entropy is entrained into the boundary layer so that the heat transfer to the surface goes up again. Both these flow regions will be discussed here for the simple case of a body of axial symmetry at zero incidence. Finally, some remarks on the flow field past a lifting body will be made. Recently, a great deal of information on these subjects has appeared in a number of reviewing papers so that little can be added. The numerical results on the subsonic flow regions in Section 2 have not been published before.

Visualization of Invasion into the Body and Internal Diffusion of Nanoparticles

2008 ◽  
Vol 396-398 ◽  
pp. 569-572
Author(s):  
Fumio Watari ◽  
Shigeaki Abe ◽  
I.D. Rosca ◽  
Atsuro Yokoyama ◽  
Motohiro Uo ◽  
...  
Keyword(s):  
Biomedical Applications ◽  
Fluorescent Microscopy ◽  
The Body ◽  
Internal Diffusion ◽  
Whole Body ◽  
X Ray ◽  
Body Level ◽  
Organ Level ◽  
Level 2 ◽  
Internal Body

Nanoparticles may invade directly into the internal body through the respiratory or digestive system and diffuse inside body. The behavior of nanoparticles in the internal body is also essential to comprehend for the realization of DDS. Thus it is necessary to reveal the internal dynamics for the proper treatments and biomedical applications of nanoparticles. In the present study the plural methods with different principles such as X-ray scanning analytical microscope (XSAM), MRI and Fluorescent microscopy were applied to enable the observation of the internal diffusion of micro/nanoparticles in the (1) whole body level, (2) inner organ level and (3) tissue and intracellular level. Chemical analysis was also done by ICP-AES for organs and compared with the results of XSAM mapping.

scholarly journals Wearable Vibration Sensor for Measuring the Wing Flapping of Insects

Sensors ◽  
2021 ◽  
Vol 21 (2) ◽  
pp. 593
Author(s):  
Ryota Yanagisawa ◽  
Shunsuke Shigaki ◽  
Kotaro Yasui ◽  
Dai Owaki ◽  
Yasuhiro Sugimoto ◽  
...  
Keyword(s):  
High Speed ◽  
Environmental Changes ◽  
Underlying Mechanism ◽  
Indirect Measurement ◽  
Feedback Mechanism ◽  
The Body ◽  
Vibration Sensor ◽  
Wingbeat Frequency ◽  
Film Sensor ◽  
Insect Wing

In this study, we fabricated a novel wearable vibration sensor for insects and measured their wing flapping. An analysis of insect wing deformation in relation to changes in the environment plays an important role in understanding the underlying mechanism enabling insects to dynamically interact with their surrounding environment. It is common to use a high-speed camera to measure the wing flapping; however, it is difficult to analyze the feedback mechanism caused by the environmental changes caused by the flapping because this method applies an indirect measurement. Therefore, we propose the fabrication of a novel film sensor that is capable of measuring the changes in the wingbeat frequency of an insect. This novel sensor is composed of flat silver particles admixed with a silicone polymer, which changes the value of the resistor when a bending deformation occurs. As a result of attaching this sensor to the wings of a moth and a dragonfly and measuring the flapping of the wings, we were able to measure the frequency of the flapping with high accuracy. In addition, as a result of simultaneously measuring the relationship between the behavior of a moth during its search for an odor source and its wing flapping, it became clear that the frequency of the flapping changed depending on the frequency of the odor reception. From this result, a wearable film sensor for an insect that can measure the displacement of the body during a particular behavior was fabricated.

scholarly journals Evidence for a vertebrate catapult: elastic energy storage in the plantaris tendon during frog jumping

2011 ◽  
Vol 8 (3) ◽  
pp. 386-389 ◽  
Author(s):  
Henry C. Astley ◽  
Thomas J. Roberts
Keyword(s):  
Energy Storage ◽  
Elastic Energy ◽  
High Speed ◽  
Angular Acceleration ◽  
Whole Body ◽  
Joint Motion ◽  
Joint Movement ◽  
Fascicle Length ◽  
Muscle Fascicle ◽  
Muscle Shortening

Anuran jumping is one of the most powerful accelerations in vertebrate locomotion. Several species are hypothesized to use a catapult-like mechanism to store and rapidly release elastic energy, producing power outputs far beyond the capability of muscle. Most evidence for this mechanism comes from measurements of whole-body power output; the decoupling of joint motion and muscle shortening expected in a catapult-like mechanism has not been demonstrated. We used high-speed marker-based biplanar X-ray cinefluoroscopy to quantify plantaris muscle fascicle strain and ankle joint motion in frogs in order to test for two hallmarks of a catapult mechanism: (i) shortening of fascicles prior to joint movement (during tendon stretch), and (ii) rapid joint movement during the jump without rapid muscle-shortening (during tendon recoil). During all jumps, muscle fascicles shortened by an average of 7.8 per cent (54% of total strain) prior to joint movement, stretching the tendon. The subsequent period of initial joint movement and high joint angular acceleration occurred with minimal muscle fascicle length change, consistent with the recoil of the elastic tendon. These data support the plantaris longus tendon as a site of elastic energy storage during frog jumping, and demonstrate that catapult mechanisms may be employed even in sub-maximal jumps.

Influence of Attached Masses on Impact Forces and Running Style in Heel-Toe Running

1987 ◽  
Vol 3 (3) ◽  
pp. 264-275 ◽  
Author(s):  
Alexander Bahlsen ◽  
Benno M. Nigg
Keyword(s):  
Body Mass ◽  
High Speed ◽  
Impact Force ◽  
Force Plate ◽  
The Body ◽  
Additional Mass ◽  
Impact Forces ◽  
Running Shoes ◽  
High Speed Film ◽  
Vertical Impact

Impact forces analysis in heel-toe running is often used to examine the reduction of impact forces for different running shoes and/or running techniques. Body mass is reported to be a dominant predictor of vertical impact force peaks. However, it is not evident whether this finding is only true for the real body mass or whether it is also true for additional masses attached to the body (e.g., running with additional weight or heavy shoes). The purpose of this study was to determine the effect of additional mass on vertical impact force peaks and running style. Nineteen subjects (9 males, 10 females) with a mean mass of 74.2 kg/56.2 kg (SD = 10.0 kg and 6.0 kg) volunteered to participate in this study. Additional masses were attached to the shoe (.05 and .1 kg), the tibia (.2, .4, .6 kg), and the hip (5.9 and 10.7 kg). Force plate measurements and high-speed film data were analyzed. In this study the vertical impact force peaks, Fzi, were not affected by additional masses, the vertical active force peaks, Fza, were only affected by additional masses greater than 6 kg, and the movement was only different in the knee angle at touchdown, ϵ0, for additional masses greater than .6 kg. The results of this study did not support findings reported earlier in the literature that body mass is a dominant predictor of external vertical impact force peaks.

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