Bat Wing Research Articles

Learning bioinspired joint geometry from motion capture data of bat flight

Bioinspired robotic systems are often designed by assuming that the kinematics of the biological system of interest are well approximated by an open kinematic chain subject to box constraints. These box-constrains are typically generated by designer interpretation of biomotion and anatomical studies or pragmatic fabrication constraints. In contrast to this standard design paradigm, this paper presents a methodology for learning joint geometry which restricts the range of motion of generic ball joints to only the reachable set observed during biomotion experiments. This reachable set is identified by constructing an analytical-empirical potential energy function over the experimental observations. The energy function effectively ‘pushes’ configurations close to the set of observations. This energy function is then thresholded to identify the zero-potential (ZP) configuration set, and joint geometry is constructed using the resulting contour. We construct an entire bat wing using this method, and demonstrate through motion capture experiments that the learned geometry successfully restricts motions to the ZP set.

Collagen fiber orientation pattern, osteon morphology and distribution, and presence of laminar histology do not distinguish torsion from bending in bat and pigeon wing bones.

Bone can adapt to its habitual load history at various levels of its hierarchical structural and material organization. However, it is unclear how strongly a bone's structural characteristics (e.g. cross-sectional shape) are linked to microstructural characteristics (e.g. distributions of osteons and their vascular canals) or ultrastructural characteristics [e.g. patterns of predominant collagen fiber orientation (CFO)]. We compared the cross-sectional geometry, microstructure and ultrastructure of pigeon (Columba livia domestica) humeri, and third metacarpals (B3M) and humeri of a large bat (Pteropus poliocephalus). The pigeon humerus is habitually torsionally loaded, and has unremodeled ('primary') bone with vessels (secondary osteons are absent) and high 'laminarity' because a large majority of these vessels course circularly with respect to the bone's external surface. In vivo data show that the bat humerus is also habitually torsionally loaded; this contrasts with habitual single-plane bending of the B3M, where invivo data show that it oscillates back and forth in the same direction. In contrast to pigeon humeri where laminar bone is present, the primary tissue of these bat bones is largely avascular, but secondary osteons are present and are usually in the deeper cortex. Nevertheless, the load history of humeri of both species is prevalent/predominant torsion, producing diffusely distributed shear stresses throughout the cross-section. We tested the hypothesis that despite microstructural/osteonal differences in these pigeon and bat bones, they will have similar characteristics at the ultrastructural level that adapt each bone for its load history. We postulate that predominant CFO is this characteristic. However, even though data reported in prior studies of bones of non-flying mammals suggest that CFO would show regional variations in accordance with the habitual 'tension regions' and 'compression regions' in the direction of unidirectional habitual bending, we hypothesized that alternating directions of bending within the same plane would obviate these regional/site-specific adaptations in the B3M. Similarly, but for other reasons, we did not expect regional variations in CFO in the habitually torsionally loaded bat and pigeon humeri because uniformly oblique-to-transverse CFO is the adaptation expected for the diffusely distributed shear stresses produced by torsion/multidirectional loads. We analyzed transverse sections from mid-diaphyses of adult bones for CFO, secondary osteon characteristics (size, shape and population density), cortical thickness in quadrants of the cortex, and additional measures of cross-sectional geometry, including the degree of circular shape that can help distinguish habitual torsion from bending. Results showed the expected lack of regional CFO differences in quasi-circular shaped, and torsionally loaded, pigeon and bat humeri. As expected, the B3M also lacked CFO variations between the opposing cortices along the plane of bending, and the quasi-elliptical cross-sectional shape and regional microstructural/osteonal variations expected for bending were not found. These findings in the B3M show that uniformity in CFO does not always reflect habitual torsional loads. Osteon morphology and distribution, and presence of laminar histology also do not distinguish torsion from bending in these bat and pigeon wing bones.

Animals in the Brain.

Pareidolic associations are commonly used in medical education to enhance perception of radiological abnormalities. A number of animal-inspired neuroradiological pareidolias have been defined which should alert clinicians to specific movement disorder diagnoses. A review of the published literature detailing neuroradiological abnormalities in movement disorder syndromes was conducted, looking specifically for established animal-inspired pareidolic associations. A number of animal-inspired neuroradiological patterns with specific movement disorder associations have been defined. These include eye of the tiger sign, face of the panda sign, swallow tail sign, hummingbird sign, Mickey Mouse sign, ears of the lynx sign, dragonfly cerebellum, tadpole sign, tigroid/leopard skin sign, and bat wing sign. Pareidolias represent a quick and easy way of enhancing perception, thereby improving the efficiency and accuracy of image analysis. Movement disorder physicians should keep in mind these associations, given that they will likely facilitate scan analysis.

Test for Borrelia spp. in bats in an urban area in the South of Brazil.

We investigated the occurrence of relapsing fever (RF) causing Borrelia genus spirochetes in synanthropic bats from the municipality of Maringá, Paraná, South of Brazil. Tissue samples from the wings of bats were collected monthly from April 2013 to February 2014 and extracted DNA was used to evaluate the presence of RF causing Borrelia spp. All bat tissues tested negative for RF causing Borrelia spp. Borrelia spp. do not occur in chiropterans from Maringá.

“The bat wing and a molar tooth in brain-Joubert syndrome”

“The bat wing and a molar tooth in brain-Joubert syndrome”

The Bat wing and a Molar tooth in brain - Joubert syndrome.

The Bat wing and a Molar tooth in brain - Joubert syndrome.

Cellular and Ionic Mechanisms of Arterial Vasomotion.

Rhythmical contractility of blood vessels was first observed in bat wing veins by Jones (Philos Trans R Soc Lond 1852:142, 131-136), and subsequently described in arteries and arterioles of multiple vascular beds in several species. Despite an abundance of descriptive literature regarding the presence of vasomotion, to date we do not have an accurate picture of the cellular and ionic basis of these oscillations in tone, or the physiological relevance of the changes in pulsatile blood flow arising from vasomotion. This chapter reviews our current understanding of the cellular and ionic mechanisms underlying vasomotion in resistance arteries and arterioles. Focus is directed to the ion channels, changes in cytosolic Ca2+ concentration, and involvement of intercellular gap junctions in the development and synchronization of rhythmic changes in membrane potential and cytosolic Ca2+ concentration within the vessel wall that contribute to vasomotion. The physiological consequences of vasomotion are discussed with a focus on the cerebral vasculature, as recent advances show that rhythmic oscillations in cerebral arteriolar diameter appear to be entrained by cortical neural activity to increase the local supply of blood flow to active regions of the brain.

Correlation between Upper Extremity Muscle Strength and Bat Swing Speed in Elementary School Baseball Players

Correlation between Upper Extremity Muscle Strength and Bat Swing Speed in Elementary School Baseball Players

Mesquite bugs, other insects, and a bat in the diet of pallid bats in southeastern Arizona.

The pallid bat (Antrozous pallidus) is a species of western North America, inhabiting ecoregions ranging from desert to oak and pine forest. They are primarily insectivorous predators on large arthropods that occasionally take small vertebrate prey, and are at least seasonally omnivorous in certain parts of their geographic range where they take nectar from cactus flowers and eat cactus fruit pulp and seeds. Until recently, mesquite bugs were primarily tropical-subtropical inhabitants of Mexico and Central America but have since occupied the southwestern United States where mesquite trees occur. Using a noninvasive method, we investigated the bats’ diet at the Cienega Creek Natural Preserve, Arizona, by collecting food parts discarded beneath three night roosts in soil-piping cavities in a mesquite bosque. We also made phenological and behavioral observations of mesquite bugs, Thasus neocalifornicus, and their interactions with the mesquite trees. We determined that the bats discarded inedible parts of 36 species in 8 orders of mainly large-bodied and nocturnal insects below the night-roosts. In addition, one partial bat wing represents probable predation upon a phyllostomid bat, Choeronycteris mexicana. About 17 of the insect taxa are newly reported as prey for pallid bats, as is the bat C. mexicana. The majority of culled insect parts (88%) were from adult mesquite bugs. Mesquite bug nymphs did not appear in the culled insect parts. After breeding in late summer, when nighttime low temperatures dropped below 21 °C, the adult bugs became immobile on the periphery of trees where they probably make easy prey for opportunistic foliage-gleaning pallid bats. Proximity of night-roosts to mesquite bug habitat probably also enhances the bats’ exploitation of these insects in this location.

A computational investigation of lift generation and power expenditure of Pratt's roundleaf bat (Hipposideros pratti) in forward flight.

The aerodynamic mechanisms of bat flight have been studied using a numerical approach. Kinematic data acquired using a high resolution motion capture system was employed to simulate the unsteady air flow around a bat’s wings. A flapping bat wing contains many degrees of freedom, which make 3D motion tracking challenging. In order to overcome this challenge, an optical motion capture system of 21 cameras was used to reduce wing self-occlusion. Over the course of a meter-long flight, 108 discrete marker points on the bat’s wings (Pratt’s roundleaf bat, Hipposideros pratti) were tracked. The time evolution of the surface of each wing was computationally reconstructed in 3D space. The resulting kinematic model was interfaced with an unsteady incompressible flow solver using the immersed boundary method (IBM) and large eddy simulation (LES). Verification and validation of the flow simulation were conducted to establish accuracy. The aerodynamic forces calculated from the simulation compared well to the forces theoretically needed to sustain the observed flight trajectory. The transient flow field generated by the simulation allowed for the direct calculation of lift, drag, and power output of the bat during flight. The mean lift coefficient was found to be 3.21, and the flap cycle averaged aerodynamic power output was 1.05 W. Throughout the flap cycle, the planform area of the wings varied up to 46% between the largest and smallest values. During the upstroke, wing rotation was found to mitigate negative lift thereby improving overall flight efficiency. The high resolution motion capture and flow simulation framework presented here has the potential to facilitate the understanding of complex bat flight aerodynamics for both straight and maneuvering flight modes.

Spondylocarpotarsal synostosis syndrome: “Bat wings” spinal fusions and “ladybug” carpal coalitions

Spondylocarpotarsal synostosis syndrome: “Bat wings” spinal fusions and “ladybug” carpal coalitions

Head-eye movement of collegiate baseball batters during fastball hitting.

Successful baseball hitting involves a combination of highly trained perceptual skills and forceful bat swing motions. The purpose of the present study was to quantify the horizontal movement of the head and eyes while baseball batters hit a fastball to clarify a visual strategy for this highly trained interceptive task. Six collegiate baseball players hit a fastball that was launched from a pitching machine. The ball speed was 31.9 m·s-1 for the Slow Ball Task and 40.3 m·s-1 for the Fast Ball Task. Horizontal head movements were analysed using images that were captured by two high-speed video cameras. The Horizontal eye movement was recorded with electrooculography. The angular speed of the horizontal head and eye movements during hitting were divided into four time periods (I-40 = 21–40% of total ball-flight, I-60 = 41–60% of total ball-flight, I-80 = 61–80% of total ball-flight, I-100 = 81–100% of total ball-flight) and analysed using analysis of variance and a Tukey post-hoc multiple-comparison. In the Slow Ball Task, the horizontal angular velocity of the head during I-80 was significantly faster than that during I-40 (p < 0.05). In the Fast Ball Task, the horizontal angular velocity of the head during I-80 was significantly faster than that during I-40 and I-60 (p < 0.05). These results indicated that the tracking motion of the head became faster as the launched ball came close to the batters, but there was no change in the angular tracking motion of the eyes. Therefore, rapid eye movement may not be suitable to accurately estimate the ball’s future location during fastball hitting based on the eye-centered coordinates. Our findings suggest that conventional vision training with a wide range of saccadic or smooth-pursuit eye movements does not reflect the characteristics of tracking strategies during baseball hitting.

Wound healing in wing membranes of the Egyptian fruit bat (Rousettus aegyptiacus) and big brown bat (Eptesicus fuscus)

Bat flight membranes are critical for locomotion, foraging, and physiological homeostasis. Wild bats frequently injure their flight membranes during interactions with the environment and conspecifics or from disease. Researchers biopsy bat wing membranes to mark individuals or collect tissue for taxonomic and molecular studies. Because there are differences in the embryological development of different wing membrane regions, we evaluated differences in flight membrane healing between 2 anatomical regions using 4-mm diameter circular biopsies in the chiropatagium and plagiopatagium of the Egyptian fruit bat (Rousettus aegyptiacus; Pteropodiformes) and the insectivorous big brown bat (Eptesicus fuscus; Vespertilioniformes). In R. aegyptiacus, plagiopatagium wounds took longer to heal to 50% of their initial area compared to chiropatagium wounds; however, this difference was not observed in E. fuscus. Plagiopatagium wounds also were more likely to enlarge in the days immediately following biopsy in R. aegyptiacus compared to E. fuscus. A sigmoid function accurately modeled wound areas and thus healing times in both species. Given the observed differences in wound-healing times between distinct regions of the bat wing membrane, our results indicate that researchers should choose a tissue biopsy location based on the species and question of interest.

Functional Characterization of Gene Regulatory Elements

Nucleotide variation in gene regulatory elements is a major determinant of phenotypes including morphological diversity between species, human variation and human disease. Despite continual progress in the cataloging of these elements, little is known about the code and grammatical rules that govern their function. Deciphering the code and their grammatical rules will enable high‐resolution mapping of regulatory elements, accurate interpretation of nucleotide variation within them and the design of sequences that can deliver molecules for therapeutic purposes. To this end, we are using massively parallel reporter assays (MPRAs) to simultaneously test the activity of thousands of gene regulatory elements in parallel. By designing MPRAs to learn regulatory grammar or to carry out saturation mutagenesis of every possible nucleotide change in disease causing gene regulatory elements, we are increasing our understanding of the phenotypic consequences of gene regulatory mutations. To better understand how nucleotide changes in gene regulatory elements lead to morphological differences between species, we are using the developing bat wing as a model. Using a combination of whole‐genome sequencing, RNA‐seq and ChIP‐seq (H3K27ac, H3K27me3) on developing bat and mouse forelimbs and hindlimbs at three sequential embryonic stages, we are attempting to decipher the molecular events that underlie bat wing development.Support or Funding InformationNICHD, NCI, NHGRI, NIMH, NHLBIThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Hip and Groin Injuries in Baseball Players.

To discuss the clinical significance of the most common hip and groin injuries in baseball players, as well as an algorithmic approach to diagnosis and treatment of these injuries. (a) Limitations in throwing velocity, pitch control, and bat swing speed may be secondary to decreased mobility and strength within the proximal kinetic chain, which must harness power from the lower extremities and core. (b) Approximately 5.5% of all baseball injuries per year involve the hip/groin and may lead to a significant amount of time spent on the disabled list. Injuries involving the hip and groin are relatively common in baseball players. Our knowledge of the mechanics of overhead throwing continues to evolve, as does our understanding of the contribution of power from the lower extremities and core. It is paramount that the team physician be able to accurately diagnose and treat injuries involving the hip/groin, as they may lead to significant disability and inability to return to elite levels of play. This review focuses on hip- and groin-related injuries in the baseball player, including femoroacetabular impingement, core muscle injury, and osteitis pubis.

The molar tooth sign and the bat wing appearance in Joubert syndrome

A 10-year-old female patient was brought to the outpatient clinic with a history of neurodevelopmental delay, gait and limb incoordination, and oculomotor apraxia. According to her parents, the girl had always showed delayed acquisition of motor milestones when compared to other children, which became more evident when she was 8 months old and was not able to sit. She was able to sit by age of 2, and walked independently, but unsteady, when she was 3.5 years old. She presented with cognitive impairment. Reviewing her history, it became clear that she was hypotonic at birth and subsequently developed gait ataxia in early childhood. She was born to nonconsanguineous parents and there were no other similar cases in her family. On physical examination, she held her head preferentially in a lateralized position to her right side. She showed gait ataxia in tandem walking, abnormal stance with a positive Romberg’s sign, dysmetria, dysdiadochokinesia, diffuse hyperreflexia, bilateral Babinski sign, and oculomotor apraxia. The Wechsler Intelligence Scale for Children-III (WISC-III) demonstrated an IQ of 67 (intellectual disability). There were no other abnormalities on physical examination. Electroencephalogram showed focal paroxysmal discharges of moderate intensity in the posterior parietal-temporal region. Brain magnetic resonance imaging (MRI) demonstrated agenesis of the cerebellar vermis with a slit in the medial line sparing the two cerebellar hemispheres (Figure 1), lengthening and thickening of the cerebellar peduncles, associated with reduction of the anteroposterior diameter of the mesencephalon, the so-called “molar tooth sign” (MTS) (Figure 2). Morphological alterations in the posterior fossa showed a 4th ventricle with a typical “bat wing” appearance (Figure 3). These findings were highly suggestive of Joubert syndrome (JS).

Low thermal dependence of the contractile properties of a wing muscle in the bat Carollia perspicillata.

Temperature affects contractile rate properties in muscle, which may affect locomotor performance. Endotherms are known to maintain high core body temperatures, but temperatures in the periphery of the body can fluctuate. Such a phenomenon occurs in bats, whose wing musculature is relatively poorly insulated, resulting in substantially depressed temperatures in the distal wing. We examined a wing muscle in the small-bodied tropical bat Carollia perspicillata and a hindlimb muscle in the laboratory mouse at 5°C intervals from 22 to 42°C to determine the thermal dependence of the contractile properties of both muscles. We found that the bat extensor carpi radialis longus had low thermal dependence from near body temperature to 10°C lower, with Q10 values of less than 1.5 for relaxation from contraction and shortening velocities in that interval, and with no significant difference in some rate properties in the interval between 32 and 37°C. In contrast, for all temperature intervals below 37°C, Q10 values for the mouse extensor digitorum longus were 1.5 or higher, and rate properties differed significantly across successive temperature intervals from 37 to 22°C. An ANCOVA analysis found that the thermal dependencies of all measured isometric and isotonic rate processes were significantly different between the bat and mouse muscles. The relatively low thermal dependence of the bat muscle likely represents a downward shift of its optimal temperature and may be functionally significant in light of the variable operating temperatures of bat wing muscles.

The Effects of Medicine Ball Training on Bat Swing Velocity in Prepubescent Softball Players

The Effects of Medicine Ball Training on Bat Swing Velocity in Prepubescent Softball Players

Bat-inspired integrally actuated membrane wings with leading-edge sensing

This paper presents a numerical investigation on the closed-loop performance of a two-dimensional actuated membrane wing with fixed supports. The proposed concept mimics aerodynamic sensing and actuation mechanisms found in bat wings to achieve robust outdoor flight: firstly, variable membrane tension, which is obtained in bats through skeleton articulation, is introduced through a dielectric-elastomer construction; secondly, leading-edge airflow sensing is achieved with bioinspired hair-like sensors. Numerical results from a coupled aero-electromechanical model show that this configuration can allow for the tracking of prescribed lift coefficient signals in the presence of disturbances from atmospheric gusts. In particular, disturbance measurements through the hair sensor (a feedforward control strategy) are seen to provide substantial advantage with respect to a reactive (feedback) control strategy determining a reduction of the oscillations of the lift coefficient.

Design of Fractal Array Bionic Ultra Wideband Antenna

According to the requirements of the second generation, the third generation, the fourth generation and the fifth generation mobile communication system, radio frequency identification system and ultra wideband communication system to the antenna's performance, the present paper originally combines bat wing bionic antenna and cross fractal array, designed a fractal array bionic ultra wideband antenna, fabricated the antenna sample and tested the radiation characteristics of the antenna. The result of test indicate that the antenna's working frequency range is 0.728-12.739 GHz, the antenna's working bandwidth is 12.011 GHz, the bandwidth octave is 17.49, the antenna return loss is less than -10 dB in the whole operating frequency band, the minimum value of return loss is -23.18 dB. This antenna completely covered the second generation mobile communication standard GSM frequency band, the third generation mobile communication standard TD-SCDMA frequency band, the third generation mobile communication standard WCDMA frequency band, the fourth generation mobile communication standard TD-LTE frequency band, the three candidate frequency bands of the fifth generation mobile communication, the three common frequency bands of the radio frequency identification system , and working band of ultra wideband communication system. This antenna can meet the requirements of small size, low thickness, low return loss and wide working bandwidth at the same time, it has a broad application prospect.