Positively selected genes of the Chinese tree shrew （Tupaia belangeri chinensis） locomotion system

While the recent release of the Chinese tree shrew （Tupaia belangeri chinensis） genome has made the tree shrew an increasingly viable experimental animal model for biomedical research, further study of the genome may facilitate new insights into the applicability of this model. For example, though the tree shrew has a rapid rate of speed and strong jumping ability, there are limited studies on its locomotion ability. In this study we used the available Chinese tree shrew genome information and compared the evolutionary pattern of 407 locomotion system related orthologs among five mammals （human, rhesus monkey, mouse, rat and dog） and the Chinese tree shrew. Our analyses identified 29 genes with significantly high co （Ka/Ks ratio） values and 48 amino acid sites in 14 genes showed significant evidence of positive selection in the Chinese tree shrew. Some of these positively selected genes, e.g. HOXA6 （homeobox A6） and AVP （arginine vasopressin）, play important roles in muscle contraction or skeletal morphogenesis. These results provide important clues in understanding the genetic bases of locomotor adaptation in the Chinese tree shrew.

Configuration Synthesis and Performance Evaluation Metrics of Lunar Rover Locomotion Systems

A method of topology synthesis based on graph theory and mechanism combination theory was applied to the configuration design of locomotion systems of lunar exploration rovers(LER).Through topology combination of wheel structural unit,suspension unit,and connecting device unit between suspension and load platform,some new locomotion system configurations were proposed and the metrics and indexes to evaluate the performance of the new locomotion system were analyzed.Performance evaluation and comparison between two LER with locomotion systems of different configurations were analyzed.The analysis results indicate that the new locomotion system configuration has good trafficability performance.

Canine Myofascial Kinetic Lines: A Descriptive Dissection Study Including Related Function and Locomotion and Comparison of the Human and Equine Myofascial Kinetic Lines

Aim: This dissection study was conducted to verify if the Myofascial kinetic lines, outlined in detail in humans and recently documented in horses, were present in dogs. These dynamic lines present rows of interconnected muscles, myofascia and other fascia structures, which influence the biomechanics of the spine and limbs. Methods: Forty-two dogs of different breeds and genders were dissected, imaged, and videoed. Results: Similar kinetic lines were verified in the dog, as described in humans and horses, and additionally, three new branches of the lines were discovered. The kinetic lines described were three superficial lines: Dorsal, Ventral, and Lateral, which all started in the hindlimb and ended in the temporal and occipital regions. These lines act respectively in spinal extension, flexion, and lateral flexion. Three profound lines, which started in the tail and ended in the head. The Deep Dorsal Line followed the transversospinal myofascia. The Deep Ventral Line showed an additional start deep in the medial hind limb, continued in the hypaxial myofascia, and enveloped all the viscera. Also, the Deep Lateral Line started in the hindlimb but parted along the trunk in the deep lateral myofascial structures. Two helical lines crossed the midline two or three times and served to rotate the spine. The Functional Line established a sling from the axilla to the contralateral stifle and presented a new ipsilateral branch. The Spiral Line connected the head and the ipsilateral tarsus and additionally presented a new straight branch. The four front limb lines describe their motion: the Front Limb Protraction and Retraction, Adduction, and Abduction Lines. Conclusion: The canine lines mirrored the equine and human lines with exceptions due to differences in anatomy, foot posture, lumbosacral flexibility, and their biomechanical constitution as predator versus prey animals. Additionally, three new canine branches were verified and described.

Inchworm locomotion gait for snakelike robot

To establish a universal and easily controlled gait for practical use of snakelike robot movement, an inchworm locomotion gait model based on a serpenoid curve is presented. By analyzing the relations of two adjacent waves in the process of locomotion and doing an approximation of the serpenoid curve, the motion function of relative angles between two adjacent links and the absolute angles between each link and the baseline on the traveling curve are built. Two efficiency criterions of the gait are given as the energy loss function f and the unit displacement in one cycle dunit.Three parameters of the criterions affecting the efficiency of the gait （ the number of links that form the traveling wave n, the included angle between two adjacent links α, and the phase difference of adjacent included angles β） are discussed by simulations and experiments. The results show that f is insensitive to n; raising n increases dunit significantly; the maximum wave amplitude of α is a decreasing function of n; and increasing α reduces the displacement influence off when n is determined. The gait model is suitable for different inchworm locomotions of a snakelike robot whose traveling waves are formed by different numbers of identical links. A wave formed by more links or a greater relative angle between two adjacent links both lead to greater velocity of the movement.

Stepping up after spinal cord injury:negotiating an obstacle during walking

Every day walking consists of frequent voluntary modifications in the gait pattern to negotiate obstacles.After spinal cord injury,stepping over an obstacle becomes challenging.Stepping over an obstacle requires sensorimotor transformations in several structures of the brain,including the parietal cortex,premotor cortex,and motor cortex.Sensory information and planning are transformed into motor commands,which are sent from the motor cortex to spinal neuronal circuits to alter limb trajectory,coordinate the limbs,and maintain balance.After spinal cord injury,bidirectional communication between the brain and spinal cord is disrupted and animals,including humans,fail to voluntarily modify limb trajectory to step over an obstacle.Therefore,in this review,we discuss the neuromechanical control of stepping over an obstacle,why it fails after spinal cord injury,and how it recovers to a certain extent.

Assessment of locomotion behavioral defects induced by acute toxicity from heavy metal exposure in nematode Caenorhabditis elegans

Locomotion behaviors are susceptible to disruption by a broad spectrum of chemicals and environmental stresses. However, no systematic testing of locomotion behavior defects induced by metal exposure has been conducted in the model organism of nematode Caenorhabditis elegans. In this study, the acute toxicity from heavy metal exposure on the locomotion behaviors was analyzed in nematodes. Endpoints of head thrash, body bend, forward turn, backward turn, and Omega/U turn were chosen to evaluate the locomotio...

Experimentation of Fish Swimming Based on Tracking Locomotion Locus

There are many kinds of swimming mode in the fish world, and we investigated two of them, used by cyprinids and bulltrout. In this paper we track the locomotion locus by marks in different flow velocity from 0.2 m·s^-1 to 0.8 m·s^-1. By fit the data above we could find out the locomotion mechanism of the two kinds of fish and generate a mathematical model of fish kine- matics. The cyprinid fish has a greater oscillation period and amplitude compared with the bulltrout, and the bulltrout changes velocity mainly by controlling frequency of oscillation.

Kinematics of Terrestrial Locomotion in Mole Cricket Gryllotalpa orientalis

The fore leg of mole cricket （Orthoptera： Glyllotalpidae） has developed into claw for digging and excavating. As the result of having a well-suited body and appendages for living underground, mole cricket still needs to manoeuvre on land in some cases with some kinds of gait. In this paper, the three-dimensional kinematics information of mole cricket in terrestrial walking was recorded by using a high speed 3D video recording system. The mode and the gait of the terrestrial walking mole cricket were investigated by analyzing the kinematics parameters, and the kinematics coupling disciplines of each limb and body were discussed. The results show that the locomotion gait of mole cricket in terrestrial walking belongs to a distinctive alternating tripod gait. We also found that the fore legs of a mole cricket are not as effective as that of common hexapod insects, its middle legs and body joints act more effective in walking and turning which compensate the function of fore legs. The terrestrial lo-comotion of mole cricket is the result of biological coupling of three pairs of legs, the distinctive alternating tripod gait and the trunk locomotion.

Circatidal rhythms of locomotion in the American horseshoe crab Limulus polyphemus: Underlying mechanisms and cues that influence them

While eye sensitivity in the American horseshoe crab Limulus polyphemus has long been known to be under the control of an endogenous circadian clock, only recently has horseshoe crab locomotion been shown to be controlled by a separate clock system. In the laboratory, this system drives clear activity rhythms throughout much of the year, not just during the mating season when horseshoe crabs express clear tidal rhythms in the field. Water temperature is a key factor influencing the expression of these rhythms： at 17~C tidal rhythms are expressed by most animals, while at I l^C expression of circatidal rhythms is rarely seen, and at 4~C rhythms are suppressed. Neither long （16：8 Light：Dark） nor short （8：16） photoperiods modify this behavior at any of these temperatures. Synchronization of these circatidal rhythms can be most readily effeeted by water pressure cycles both in situ and in the lab, while temperature and current cycles play lesser, but possibly contributory, roles. Interestingly, Light：Dark cycles appear to have synchronizing as well as ＂masking＂ effects in some individuals. Evidence that each of two daily bouts of activity are independent suggests that the Limulus circatidal rhythm of locomotion is driven by two （circalunidian） clocks, each with a period of 24.8h. While the anatomical locations of either the circadian clock, that drives fluctuations in visual sensitivity, or the circatidal clock, that controls tidal rhythms of locomotion, are currently unknown, preliminary molecular analyses have shown that a 71 kD protein that reacts with antibodies directed against the Drosophila PERIOD （PER） protein is found in both the pro- tocerebrum and the subesophageal ganglion

Differences in cocaine-induced place preference persistence, locomotion and social behaviors between C57BL/6J and BALB/cJ mice

C57BL/6J and BALB/cJ mice display significant differences in sociability and response to drugs, but the phenotypic variability of their susceptibility to cocaine is still not well known. In this study, the differences between these two mice strains in the persistence of cocaine-induced conditioned place preference （CPP）, as well as the locomotion and social behaviors after the 24-hour withdrawal from a four-day cocaine （20 mg/kg/day） administration were investigated. The results showed that the cocaine-induced CPP persisted over two weeks in C57BL/6J mice, while it diminished within one week among BALB/cJ mice. After 24-hours of cocaine withdrawal, high levels of locomotion as well as low levels of social interaction and aggressive behavior were found in C57BL/6J mice, but no significant changes were found in BALB/cJ mice, indicating that cocaine-induced CPP persistence, locomotion and social behavior are not consistent between these two strains, and that overall C57BL/6J mice are more susceptible to cocaine than BALB/cJ mice at the tested doses.

Investigation on Walking and Pacing Stability of German Shepherd Dog for Different Locomotion Speeds

The motion of three German Shepherd Dogs on a treadmill was recorded using a three-dimensional motion capture system. The locomotion speed of the dog was respectively set at 4km·h^-1, 5.5km·h^-1, 7 km·h^-1 and 8.5 km·h^-1. By processing the acquired data, the joint trajectories of the dogs＇ hind limbs were computed and a time series analysis was conducted. Joint angle-angle diagrams were obtained and the Lyapunov exponents were computed. Results show that the stability decreased when speed increased, which can be attributed to the decrease in the stance phase respect to the swing phase when speed is increased. Results also show that the dogs changed gait during the tests, namely walking in the range of 4 km·h^-1 to 7 km·h^-1 and pacing at 8.5 km·h^-1 A significant drop in stability was observed from walking to pacing.

Effect of lead on survival, locomotion and sperm morphology of Asian earthworm, Pheretima guillelmi

To provide basic toxicity data for formulating risk characterization benchmarks, the effects of lead on survival, locomotion, and sperm morphology were investigated in the Asian earthworm Pheretima guillelmi. The LC50 of P. guiUelmi for 7 and 14 d were 4285＋339 mg/kg and 3207＋248 mg/kg, which shows P. guillelmi can tolerate a higher concentration of lead nitrate. The average weight of the surviving earthworms decreased at concentration of 2800 mg Pb/kg soil, and the locomotor ability of earthworms exposed to a range of soil Pb concentrations showed a general decrease with increasing Pb concentrations. We also presented data depicting the sperm morphology of earthworms, which shows potential as a sensitive biomarker for measuring the effects of heavy metal on reproduction.

Segmental Kinematic Coupling of the Human Spinal Column during Locomotion

As one of the most important daily motor activities, human locomotion has been investigated intensively in recent decades. The locomotor functions and mechanics of human lower limbs have become relatively well understood. However, so far our understanding of the motions and functional contributions of the human spine during locomotion is still very poor and simultaneous in-vivo limb and spinal column motion data are scarce. The objective of this study is to investigate the delicate in-vivo kinematic coupling between different functional regions of the human spinal column during locomotion as a stepping stone to explore the locomotor function of the human spine complex. A novel infrared reflective marker cluster system was constrncted using stereophotogrammetry techniques to record the 3D in-vivo geometric shape of the spinal column and the segmental position and orientation of each functional spinal region simultaneously. Gait measurements of normal walking were conducted. The preliminary results show that the spinal column shape changes periodically in the frontal plane during locomotion. The segmental motions of different spinal functional regions appear to be strongly coupled, indicating some synergistic strategy may be employed by the human spinal column to facilitate locomotion. In contrast to traditional medical imaging-based methods, the proposed technique can be used to investigate the dynamic characteristics of the spinal column, hence providing more insight into the functional biomechanics of the human spine.

Locomotion Optimization and Manipulation Planning of a Tetrahedron-Based Mobile Mechanism with Binary Control

Locomotion and manipulation optimization is essential for the performance of tetrahedron-based mobile mechanism. Most of current optimization methods are constrained to the continuous actuated system with limited degree of freedom(DOF), which is infeasible to the optimization of binary control multi-DOF system. A novel optimization method using for the locomotion and manipulation of an 18 DOFs tetrahedron-based mechanism called 5-TET is proposed. The optimization objective is to realize the required locomotion by executing the least number of struts.Binary control strategy is adopted, and forward kinematic and tipping dynamic analyses are performed, respectively.Based on a developed genetic algorithm(GA), the optimal number of alternative struts between two adjacent steps is obtained as 5. Finally, a potential manipulation function is proposed, and the energy consumption comparison between optimal 5-TET and the traditional wheeled robot is carried out. The presented locomotion optimization and manipulation planning enrich the research of tetrahedron-based mechanisms and provide the instruction to the successive locomotion and operation planning of multi-DOF mechanisms.

A Bionic Neural Network for Fish-Robot Locomotion

A bionic neural network for fish-robot locomotion is presented. The bionic neural network inspired from fish neural net- work consists of one high level controller and one chain of central pattern generators （CPGs）. Each CPG contains a nonlinear neural Zhang oscillator which shows properties similar to sine-cosine model. Simulation re, suits show that the bionic neural network presents a good performance in controlling the fish-robot to execute various motions such as startup, stop, forward swimming, backward swimming, turn right and turn left.

Mechanical design and locomotion control of a homogenous lattice modular self-reconfigurable robot

In this paper, we propose a novel, 3D, like cubic shape, modular self-reconfigurable (MSR) robot named M-Cubes. Its key mechanical components are analyzed in detail. By communicating with the neighboring modules, each unit employs its automatic lock device composed of a pin and a hole on each connection plane which can connect or disconnect with neighboring modules. The M-Cubes system consisting of many identical modules cooperates to change their connection, and then the whole structure transforms into arbitrary structure. Furthermore, we describe its locomotion control based on the driving function and the adjacency matrix which is effective for solving the computationally difficult problem and optimizing the system motion path during the self-reconfiguration process. Finally, a simulation experiment using java 3D technology, proved the new method for controlling modular robot is robust and useful.

Monoaminergic and catecholaminergic activation of the central pattern generator for locomotion following spinal cord injury Innovative therapeutic approaches

The development of secondary health complications following spinal cord injury has been increasingly recognized by healthcare professionals as a major concern. These problems most specifically affect complete or near-complete spinal cord injury patients （e.g., those with minimal mobility）, who are not typically rehabilitated with treadmill training approaches, because motor control and leg movements are largely impaired. However, recent pharmaceutical advances in central pattern generator activation may provide new therapeutic hopes for these spinal cord injury patients. This article provides a comprehensive overview, for the non-specialist, of the most recent advances in this field.

Locomotion and Depth Control of Robotic Fish with Modular Undulating Fins

This paper presents an environmental-friendly robotic system mimicking the undulating fins of a fish.To mimic the actual flexible fin of real fish,a fin-like mechanism with a series of connecting linkages is modeled and attached to the robotic fish,by virtue of a specially designed strip.Each link is able to turn and slide with respect to the adjacent link.These driving linkages are then used to form a mechanical fin consisting of several fin segments,which are able to produce undulations,similar to those produced by the actual fish fins.Owing to the modular and re-configurable design of the mechanical fin,we are able to construct biomimetic robotic fish with various swimming modes by fin undulations.Some qualitative and workspace observations by experiments of the robotic fish are shown and discussed.

Metabolic recruitment of spinal locomotion:intracellular neuromodulation by trace amines and their receptors

The trace amines（TAs）are a family of endogenous amines with structural,metabolic,physiological and pharmacological similarities to classical monoamine neurotransmitters.The TA family includes tyramine,octopamine,β-phenylethylamine（PEA）,and tryptamine（Figure 1）.

3-D Locomotion control for a biomimetic robot fish

This paper concerns with 3-D locomotion control methods for a biomimetic robot fish. The system architecture of the fish is firstly presented based on a physical model of carangiform fish. The robot fish has a flexible body, a rigid caudal fin and a pair of pectoral fins, driven by several servomotors. The motion control of the robot fish are then divided into speed control, orientation control, submerge control and transient motion control, corresponding algorithms are detailed respectively. Finally, experiments and analyses on a 4-link, radio-controlled robot fish prototype with 3-D locomotion show its good performance.