Learning From the Fins of Ray-Finned Fish for the Propulsors of Unmanned Undersea Vehicles

2011 ◽  
Vol 45 (4) ◽  
pp. 65-73 ◽  
Author(s):  
James L. Tangorra ◽  
Timo Gericke ◽  
George V. Lauder
Keyword(s):  
High Speed ◽  
The Body ◽  
External Disturbances ◽  
Pectoral Fins ◽  
Autonomous Regulation ◽  
Wide Range ◽  
Sensorimotor Systems ◽  
And Control ◽  
Vortex Perturbations

AbstractAdvanced propulsors are required to help unmanned undersea vehicles (UUVs) overcome major challenges associated with energy and autonomy. The fins of ray-finned fish provide an excellent model from which to develop propulsors that can create forces efficiently and drive a wide range of behaviors, from hover to low-speed maneuvers to high-speed travel. Although much is known about the mechanics of fins, little is known about the fin’s sensorimotor systems or how fins are regulated in response to external disturbances. This information is crucial for implementing propulsive and control systems that exploit the same phenomena as the biological fins for efficiency, effectiveness, and autonomous regulation. Experiments were conducted to evaluate the in vivo response of the sunfish and its pectoral fins to vortex perturbations applied directly to the fish and to the fins. The fish and the fins responded actively to perturbations that disturbed the motion of the fish body. Surprisingly, perturbations that deformed the fins extensively did not cause a reaction from either the fins or the body. These results indicate that the response of the pectoral fins to large deformations is not reflexive and that fin motions are regulated when it is necessary to correct for disturbances to the motion of the fish. The results also demonstrate a benefit of compliance in propulsors, in that external perturbations can disturb the fins without having its impact be transferred to the fish body.

Locomotor function of the dorsal fin in teleost fishes: experimental analysis of wake forces in sunfish

2001 ◽  
Vol 204 (17) ◽  
pp. 2943-2958 ◽  
Author(s):  
Eliot G. Drucker ◽  
George V. Lauder
Keyword(s):  
High Speed ◽  
Lepomis Macrochirus ◽  
The Body ◽  
Cycle Period ◽  
Teleost Fishes ◽  
Caudal Fin ◽  
Locomotor System ◽  
Pectoral Fins ◽  
Dorsal Fin

SUMMARYA key evolutionary transformation of the locomotor system of ray-finned fishes is the morphological elaboration of the dorsal fin. Within Teleostei, the dorsal fin primitively is a single midline structure supported by soft, flexible fin rays. In its derived condition, the fin is made up of two anatomically distinct portions: an anterior section supported by spines, and a posterior section that is soft-rayed. We have a very limited understanding of the functional significance of this evolutionary variation in dorsal fin design. To initiate empirical hydrodynamic study of dorsal fin function in teleost fishes, we analyzed the wake created by the soft dorsal fin of bluegill sunfish (Lepomis macrochirus) during both steady swimming and unsteady turning maneuvers. Digital particle image velocimetry was used to visualize wake structures and to calculate in vivo locomotor forces. Study of the vortices generated simultaneously by the soft dorsal and caudal fins during locomotion allowed experimental characterization of median-fin wake interactions.During high-speed swimming (i.e. above the gait transition from pectoral- to median-fin locomotion), the soft dorsal fin undergoes regular oscillatory motion which, in comparison with analogous movement by the tail, is phase-advanced (by 30% of the cycle period) and of lower sweep amplitude (by 1.0cm). Undulations of the soft dorsal fin during steady swimming at 1.1bodylengths−1 generate a reverse von Kármán vortex street wake that contributes 12% of total thrust. During low-speed turns, the soft dorsal fin produces discrete pairs of counterrotating vortices with a central region of high-velocity jet flow. This vortex wake, generated in the latter stage of the turn and posterior to the center of mass of the body, counteracts torque generated earlier in the turn by the anteriorly positioned pectoral fins and thereby corrects the heading of the fish as it begins to translate forward away from the turning stimulus. One-third of the laterally directed fluid force measured during turning is developed by the soft dorsal fin. For steady swimming, we present empirical evidence that vortex structures generated by the soft dorsal fin upstream can constructively interact with those produced by the caudal fin downstream. Reinforcement of circulation around the tail through interception of the dorsal fin’s vortices is proposed as a mechanism for augmenting wake energy and enhancing thrust.Swimming in fishes involves the partitioning of locomotor force among several independent fin systems. Coordinated use of the pectoral fins, caudal fin and soft dorsal fin to increase wake momentum, as documented for L. macrochirus, highlights the ability of teleost fishes to employ multiple propulsors simultaneously for controlling complex swimming behaviors.

In-vivo evaluation of lipid lowering ability of Chloris paraguaiensis extracts

2020 ◽  
Vol 7 (2) ◽  
pp. 21-24
Author(s):  
Pavani C H
Keyword(s):  
Medicinal Plants ◽  
Chemical Constituents ◽  
The Body ◽  
Lipid Lowering ◽  
Medical Systems ◽  
In Vivo Evaluation ◽  
Standard Drug ◽  
Anti Oxidant ◽  
And Control

Hyperlipidemia is the immediate results of the excessive fat intake in food. This results in the elevated levels of cholesterol and triglycerides in the blood. This leads to heart conditions like CAD, hypertension, congestive heart failure as risk factors which can be lethal. There are many drugs to treat and control the lipids levels in the body. These drugs are either designed to prevent LDL accumulation and VLDL synthesis. Some drugs also lower the elevated levels of saturated lipids in the body. But many drugs are known to cause side effects and adverse effects; therefore, alternatives to the drugs are the subjects for current investigations. Herbs and medicinal plants are used as treatment sources for many years. They have been used in the Indian medical systems like Ayurveda, Siddha etc. As the application of herbs in the treatment is growing, there is an urgent need for the establishment of Pharmacological reasoning and standardization of the activity of the medicinal plants. Chloris paraguaiensis Steud. is Poyaceae member that is called locally as Uppugaddi. Traditionally it is used to treat Rheumatism, Diabetes, fever and diarrhoea. The chemical constituents are known to have anti-oxidant properties and most of the anti-oxidants have anti-hyperlipidemic activity too. Since the plant has abundant flavonoid and phenol content, the current research focusses on the investigation of the anti-hyperlipidemic activity of the plant Chloris extracts. Extracts of Chloris at 200mg/kg showed a comparably similar anti hyperlipidemia activity to that of the standard drug. The extracts showed a dose based increase in the activity at 100 and 200mg/kg body weight.

scholarly journals Clinical and in Vivo Response Following Surgery or Surgery Plus Adjuvant Chemotherapy or Immunotherapy for Colorectal Carcinoma in a Rat Model

1983 ◽  
Vol 76 (10) ◽  
pp. 833-840 ◽  
Author(s):  
A K House ◽  
M A L Maley
Keyword(s):  
Body Weight ◽  
Adjuvant Chemotherapy ◽  
Surgical Excision ◽  
The Body ◽  
Recurrent Tumour ◽  
Mesenteric Node ◽  
And Control ◽  
Tumour Weight

Two cohorts of rats, 240 with colon cancer and 150 controls, were assessed clinically and immunologically for their response to tumour and its management which was either by surgical excision alone or by surgical excision combined with either adjuvant chemotherapy or immunotherapy. The histology and invasion characteristics were observed for similarity with those of human lesions. Metastases were found in liver, lymph nodes, the peritoneum or lungs in 27% of animals during follow up. Significantly fewer adjuvant-treated rats had metastases than those receiving surgery alone ( P < 0.05), and less total tumour weight was found in the adjuvant-treated rats at four ( P < 0.03) and six ( P < 0.001) weeks postoperatively. Animals in the adjuvant immunotherapy group survived longer than in either other group ( P < 0.001). The crude parameters of host response to tumour, body, spleen and mesenteric lymph node weight were recorded and the latter two indexed to body weight. The body weight of tumour and control rats increased significantly with time ( P < 0.04). The spleen and mesenteric node indices were significantly ( P < 0.04) greater in tumour than control rats and were varied by recurrent tumour growth and by the adjuvant treatment administered postoperatively.

The C-start escape response ofPolypterus senegalus: bilateral muscle activity and variation during stage 1 and 2

2002 ◽  
Vol 205 (17) ◽  
pp. 2591-2603 ◽  
Author(s):  
Eric D. Tytell ◽  
George V. Lauder
Keyword(s):  
Muscle Activity ◽  
Escape Response ◽  
High Speed ◽  
Wave Speed ◽  
Activity Patterns ◽  
Motor Pattern ◽  
The Body ◽  
Wide Range ◽  
Fast Start ◽  
Stage 1

SUMMARYThe fast-start escape response is the primary reflexive escape mechanism in a wide phylogenetic range of fishes. To add detail to previously reported novel muscle activity patterns during the escape response of the bichir, Polypterus, we analyzed escape kinematics and muscle activity patterns in Polypterus senegalus using high-speed video and electromyography (EMG). Five fish were filmed at 250 Hz while synchronously recording white muscle activity at five sites on both sides of the body simultaneously (10 sites in total). Body wave speed and center of mass velocity, acceleration and curvature were calculated from digitized outlines. Six EMG variables per channel were also measured to characterize the motor pattern. P. senegalus shows a wide range of activity patterns, from very strong responses, in which the head often touched the tail, to very weak responses. This variation in strength is significantly correlated with the stimulus and is mechanically driven by changes in stage 1 muscle activity duration. Besides these changes in duration, the stage 1 muscle activity is unusual because it has strong bilateral activity, although the observed contralateral activity is significantly weaker and shorter in duration than ipsilateral activity. Bilateral activity may stiffen the body, but it does so by a constant amount over the variation we observed; therefore, P. senegalus does not modulate fast-start wave speed by changing body stiffness. Escape responses almost always have stage 2 contralateral muscle activity, often only in the anterior third of the body. The magnitude of the stage 2 activity is the primary predictor of final escape velocity.

Challenges on the effect of cell phone radiation on mammalian embryos and fetuses: a review of the literature

Zygote ◽  
2021 ◽  
pp. 1-7
Author(s):  
Maryam Mahaldashtian ◽  
Mohammad Ali Khalili ◽  
Fatemeh Anbari ◽  
Mohammad Seify ◽  
Manuel Belli
Keyword(s):  
Embryo Development ◽  
Animal Studies ◽  
Cell Phones ◽  
Cellular Phone ◽  
The Body ◽  
Human Embryos ◽  
Success Rates ◽  
Wide Range

Summary Cell phones operate with a wide range of frequency bands and emit radiofrequency-electromagnetic radiation (RF-EMR). Concern on the possible health hazards of RF-EMR has been growing in many countries because these RF-EMR pulses may be absorbed into the body cells, directly affecting them. There are some in vitro and in vivo animal studies related to the consequences of RF-EMR exposure from cell phones on embryo development and offspring. In addition, some studies have revealed that RF-EMR from cellular phone may lead to decrease in the rates of fertilization and embryo development, as well as the risk of the developmental anomalies, other studies have reported that it does not interfere with in vitro fertilization or intracytoplasmic sperm injection success rates, or the chromosomal aberration rate. Of course, it is unethical to study the effect of waves generated from cell phones on the forming human embryos. Conversely, other mammals have many similarities to humans in terms of anatomy, physiology and genetics. Therefore, in this review we focused on the existing literature evaluating the potential effects of RF-EMR on mammalian embryonic and fetal development.

Kinematics and efficiency of steady swimming in adult axolotls (Ambystoma mexicanum)

1997 ◽  
Vol 200 (13) ◽  
pp. 1863-1871 ◽  
Author(s):  
K D'Août ◽  
P Aerts
Keyword(s):  
Swimming Speed ◽  
High Speed ◽  
Natural Habitat ◽  
Total Body Length ◽  
Ambystoma Mexicanum ◽  
The Body ◽  
Entire Body ◽  
Amplitude Profile ◽  
Wide Range ◽  
Tail Tip

The kinematics of steady swimming at a wide range of velocities was analysed using high-speed video recordings (500 frames s-1) of eight individuals of Ambystoma mexicanum swimming through a tunnel containing stationary water. Animals in the observed size range (0.135&shy;0.238 m total body length) prefer to swim at similar absolute speeds, irrespective of their body size. The swimming mechanism is of the anguilliform type. The measured kinematic variables &shy; the speed, length, frequency and amplitude (along the entire body) of the propulsive wave &shy; are more similar to those of anguilliform swimming fish than to those of tadpoles, in spite of common morphological features with the latter, such as limbs, external gills and a tapering tail. The swimming speed for a given animal size correlates linearly with the tailbeat frequency (r2=0.71), whereas the wavelength and tail-tip amplitude do not correlate with this variable. The shape of the amplitude profile along the body, however, is very variable between the different swimming bouts, even at similar speeds. It is suggested that, for a given frequency, the amplitude profile along the body is adjusted in a variable way to yield the resulting swimming speed rather than maintaining a fixed-amplitude profile. The swimming efficiency was estimated by calculating two kinematic variables (the stride length and the propeller efficiency) and by applying two hydrodynamic theories, the elongated-body theory and an extension of this theory accounting for the slope at the tail tip. The latter theory was found to be the most appropriate for the axolotl's swimming mode and yields a hydromechanical efficiency of 0.75&plusmn;0.04 (mean &plusmn; s.d.), indicating that Ambystoma mexicanum swims less efficiently than do anuran tadpoles and most fishes. This can be understood given its natural habitat in vegetation at the bottom of lakes, which would favour manoeuvrability and fast escape.

ANP kinetics in normal men: in vivo measurement by a tracer method and correlation with sodium intake

1993 ◽  
Vol 264 (3) ◽  
pp. F480-F489 ◽  
Author(s):  
G. Iervasi ◽  
A. Clerico ◽  
S. Berti ◽  
A. Pilo ◽  
F. Vitek ◽  
...  
Keyword(s):  
High Performance ◽  
Sodium Intake ◽  
Mean Transit Time ◽  
Normal Subjects ◽  
The Body ◽  
Metabolic Clearance ◽  
Healthy Human ◽  
Large Space ◽  
Wide Range

125I-labeled atrial natriuretic peptide (ANP) was bolus injected into seven healthy human male subjects on an unrestricted diet (sodium intake ranging from 80 to 300 mmol/day). A high-performance liquid chromatographic procedure was used to purify the labeled hormone and the principal labeled metabolites in venous plasma samples collected up to 50 min after injection. The main ANP kinetic parameters were derived from the disappearance curves of the 125I-ANP, which were satisfactorily fitted by a biexponential function in all subjects. Newly produced ANP initially distributes in a large space (plasma-equivalent volume is 12.1 +/- 3.6 l/m2 body surface); the hormone rapidly leaves this sampling space through both degradation and distribution in peripheral spaces, as indicated by the single-pass mean transit time through the sampling space (3.9 +/- 1.2 min). The mean residence time in the body (22.7 +/- 23.1 min) and the plasma-equivalent total distribution volume (30.9 +/- 12.0 l/m2) indicate that ANP is also widely distributed outside the initial space. Metabolic clearance rate (MCR) values were distributed across a wide range (from 740 to 2,581 ml.min-1 x m-2) and were shown to correlate strongly with the daily urinary excretion of sodium. These results indicate that: 1) newly produced ANP is rapidly distributed and degraded, 2) the body pool of the hormone can be considered as a combination of two exchanging spaces, 3) circulating ANP is < or = 1/15 of the body pool, and 4) MCR of ANP is closely related to sodium intake, at least in normal subjects on a free sodium intake diet.

Direct Determination of the Body Content of Radionuclides: Abstract

2003 ◽  
Vol 3 (1) ◽  
pp. 9-9
Author(s):  
R. Griffith ◽  
H. Bergmann ◽  
F. A. Fry ◽  
D. Hickman ◽  
J.-L. Genicot ◽  
...  
Keyword(s):  
Direct Measurement ◽  
Direct Determination ◽  
The Body ◽  
Whole Body ◽  
Control Measurement ◽  
In Vivo Measurement ◽  
Calibration Methods ◽  
Partial Body ◽  
And Control

Previous ICRU reports have dealt with the formulation and properties of tissue substitutes and phantoms that are used to calibrate in vivo measurement systems. This report provides guidance on the overall process of the direct measurement of radionuclides in the human body for radiation protection and medical applications. It addresses the detectors and electronics used for the measurement; methods of background reduction and control; measurement geometries for whole body, partial body or organ counting; physical and mathematical calibration methods; data analysis; and quality assurance. It is directed to readers who need practical advice on the establishment and operation of direct measurement facilities.

A System of Notation and Measurement for Space Suit Mobility Evaluation

1968 ◽  
Vol 10 (1) ◽  
pp. 79-93 ◽  
Author(s):  
John A. Roebuck
Keyword(s):  
Integrated System ◽  
The Body ◽  
Human Engineering ◽  
Space Suit ◽  
Body Movements ◽  
Angular Coordinate ◽  
Workspace Analysis ◽  
Wide Range ◽  
And Control ◽  
Standard Techniques

An integrated system of mobility notation and standard techniques for measurement of spacesuit mobility is described. New terminology is proposed to describe human body movements for engineering workspace analysis and suit mobility specifications. Vector and link concepts are combined in a simplified model of man to describe body positions in terms of orientation of limbs with respect to a tri-planar angular coordinate system conceived as attached to the pelvic region. Numerical coding of the body links and joints is described. The notation system may be used as a basis for mathematical modeling for computer analysis of vehicle workspace geometry and control locations. The system is independent of gravitational reference semantic implications and sufficiently general for a wide range of complexity in kinesiological, medical, and human engineering applications.

A Study of Changes in Whole-Body Calcium, Phosphorus, Sodium and Nitrogen by Neutron Activation Analysis in Vivo in Rats on a Calcium-Deficient Diet

1976 ◽  
Vol 51 (4) ◽  
pp. 399-402
Author(s):  
K. Boddy ◽  
R. Lindsay ◽  
I. Holloway ◽  
D. A. S. Smith ◽  
A. Elliott ◽  
...  
Keyword(s):  
Neutron Activation Analysis ◽  
Activation Analysis ◽  
The Body ◽  
Whole Body ◽  
Deficient Diet ◽  
Calcium Phosphorus ◽  
Dietary Period ◽  
Total Body ◽  
And Control

1. A method of measuring changes in the total body content of calcium, phosphorus, nitrogen and sodium in rats by activation analysis in vivo is described. 2. The change in the body content of the elements has been measured in rats on a calcium-deficient diet and in control animals, the body nitrogen being used to represent lean body mass for normalization. 3. There were significant differences in Ca/N and P/N but not in Ca/P ratios between the animals on a deficient diet and control animals at the end of the dietary period.

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