Attachment Devices Research Articles

Evidence for a sexually selected function of the attachment system in bedbugs Cimex lectularius (Heteroptera, Cimicidae).

Attachment to surfaces is a major aspect of an animal's interaction with the environment. Consequently, shaping of the attachment system in relation to weight load and substrate is considered to have occurred mainly by natural selection. However, sexual selection may also be important because many animals attach to their partner during mating. The two hypotheses generate opposing predictions in species where males are smaller than females. Natural selection predicts that attachment ability will scale positively with load, and hence body size, and so will be larger in females than males. Sexual selection predicts attachment forces in males will be larger than those in females, despite the males' smaller size because males benefit from uninterrupted copulation by stronger attachment to the female. We tested these predictions in the common bedbug Cimex lectularius, a species in which both sexes, as well as nymphs, regularly carry large loads: blood meals of up to 3times their body weight. By measuring attachment forces to smooth surfaces and analysing in situ fixed copulating pairs and the morphology of attachment devices, we show that: (i) males generate twice the attachment force of females, despite weighing 15% less; (ii) males adhere to females during copulation using hairy tibial adhesive pads; (iii) there are more setae, and more setae per unit area, in the pads of males than in those of females but there is no difference in the shape of the tarsal setae; and (iv) there is an absence of hairy tibial attachment pads and a low attachment force in nymphs. These results are consistent with a sexually selected function of attachment in bedbugs. Controlling sperm transfer and mate guarding by attaching to females during copulation may also shape the evolution of male attachment structures in other species. More generally, we hypothesise the existence of an arms race in terms of male attachment structures and female counterparts to impede attachment, which may result in a similar evolutionary diversification to male genitalia.

Complementary effect of attachment devices in stick insects (Phasmatodea).

Stick insects are well adapted in their locomotion to various surfaces and topographies of natural substrates. Single pad measurements characterised the pretarsal arolia of these insects as shear-sensitive adhesive pads and the tarsal euplantulae as load-sensitive friction pads. Different attachment microstructures on the euplantulae reveal an adaptation of smooth euplantulae to smooth surfaces and nubby eupantulae to a broader range of surface roughness. However, how different attachment pads and claws work in concert and how strong the contribution of different structures is to the overall attachment performance remains unclear. We therefore assessed combinatory effects in the attachment system of two stick insect species with different types of euplantular microstructures by analysing their usage in various posture situations and the performance on different levels of substrate roughness. For comparison, we provide attachment force data of the whole attachment system. The combination of claws, arolia and euplantulae provides mechanical interlocking on rough surfaces, adhesion and friction on smooth surfaces in different directions, and facilitates attachment on different inclines and on a broad range of surface roughness, with the least performance in the range 0.3-1.0 µm. On smooth surfaces, stick insects use arolia always, but employ euplantulae if the body weight can generate load on them (upright, wall). On structured surfaces, claws enable mechanical interlocking at roughnesses higher than 12 µm. On less-structured surfaces, the attachment strength depends on the use of pads and, corroborating earlier studies, favours smooth pads on smooth surfaces, but nubby euplantulae on micro-rough surfaces.

To cap/cuff or ring: do distal attachment devices improve the adenoma detection?

ABSTRACTIntroduction: Colonoscopy reduces the risk of colorectal cancer, by interrupting the adenoma–carcinoma sequence enabling the detection and removal of adenomas before they turn into colorectal cancer. Colonoscopy has its limitations as adenoma miss rates as high as 25% have been reported. The reasons for missed pathology are complicated and multi-factorial. The recent drive to improve adenoma detection rates has led to a plethora of new technologies.Areas covered: An increasing number of advanced endoscopes and distal attachment devices have appeared in the market. Advanced endoscopes aim to improve mucosal visualization by widening the field of view. Distal attachment devices aim to increase adenoma detection behind folds by flattening folds on withdrawal. In this review article, we discuss the three following distal attachment devices: the transparent cap, the Endocuff, and the Endoring.Expert commentary: The authors believe that the distal attachment devices will have a greater benefit for endoscopists with low baseline adenoma detection rates.

Restoring Natural Forearm Rotation in Transradial Osseointegrated Amputees

Osseointegrated transradial prostheses have the potential to preserve the natural range of wrist rotation, which improves the performance of activities of daily living and reduces compensatory movements that potentially lead to secondary health problems over time. This is possible by enabling the radius and the ulna bone to move with respect to each other, restoring the functionality of the original distal-radioulnar joint. In this paper, we report on psychophysics tests performed on an osseointegrated transradial amputee with the aim to understand the extent of mobility of the implants that is required to preserve the natural forearm rotation. Based on these experiments, we designed and developed an attachment device between the implants and the hand prosthesis that serves as an artificial distal radio-ulnar joint. This device was fitted on an osseointegrated transradial amputee and its functionality assessed by means of the Southampton Hand Assessment Procedure (SHAP) and the Minnesota Manual Dexterity test (MMDT). We found that the axial rotation of the implants is required to preserve forearm rotation, to distribute loads equally over the two implants (60% radius - 40% ulna), and to enable loading of the implants without unpleasant feelings for the patient. Higher function was recorded when our attachment device enabled forearm rotation: SHAP from 61 to 71, MMDT from 258s to 231s. Natural forearm rotation can be successfully restored in transradial amputees by using osseointegration and our novel mechanical attachment to the hand prosthesis.

Attachment ability of the polyphagous bug Nezara viridula (Heteroptera: Pentatomidae) to different host plant surfaces

The present investigation tests through friction experiments the attachment ability of adults of the southern green stink bug Nezara viridula L. (Heteroptera: Pentatomidae), a polyphagous insect representing a cosmopolitan pest, on different host plant species characterized by smooth, hairy and waxy surfaces. Surfaces of different tested plants have been studied in Cryo-Scanning Electron Microscope (Cryo-SEM). The load cell force transducer was used to evaluate the potential damage to the insect attachment devices induced by walking on the different leaf surfaces. In case of the plant Phaseolus vulgaris, where insects showed a strong reduction in their adhesion ability during and after walking on the leaf, the damage to the insect by two cultivars with different morphological features and the insect ability to recover after 24 h has been evaluated. The ability to recover notwithstanding the damage to attachment devices, shown by Cryo-SEM investigations, together with the strong attachment forces produced on various plant leaves, characterized by different morphological features, is in agreement with the great adaptability and ecological plasticity of this widely-spread bug species. The present study, increasing our knowledge on the mechanical interaction of this species with different host plant species, can help to develop new strategies to control this insect pest.

The legs of “spider associated” parasitic primary larvae of Mantispa aphavexelte (Mantispidae, Neuroptera) – Attachment devices and phylogenetic implications

The legs of the primary larva of Mantispa aphavexelte, parasite in egg sacks of spiders, were examined using scanning electron microscopy (SEM), histology and confocal laser scanning microscopy (CLSM). The leg morphology is described in detail, including intrinsic muscles. Functional adaptations of the leg attachment devices are discussed, especially regarding the material composition. For example, a sole-like flexible ventral tarsal surface containing resilin is combined with sclerotized pseudo-claws. This likely enables the larvae to cope with surface structures on the spider's body, with substrates on the ground, and also with various structural elements in the spider's nest. The leg morphology is evaluated with respect to phylogenetic affinities. A trumpet-shaped, elongated empodium has likely evolved early in the evolution of Neuroptera and may consequently belong to the groundplan of a large subgroup of the order. It characterizes most groups of the hemerobiform lineage and is also present in the myrmeleontiform Psychopsidae. The presence of a tarsal protrusion resembling a pretarsus confirms the monophyletic origin of Mantispoidea. A single fixed tooth and a specific surface structure are potential autapomorphies of Mantispidae. A distal tibial subunit partly separated from the main part of the leg segment is an apomorphy only described for larvae of M. aphavexelte.

Exam 1: Comparative Efficacy of Colonoscope Distal Attachment Devices in Increasing Rates of Adenoma Detection: A Network Meta-analysis

Exam 1: Comparative Efficacy of Colonoscope Distal Attachment Devices in Increasing Rates of Adenoma Detection: A Network Meta-analysis

Contribution of different tarsal attachment devices to the overall attachment ability of the stink bug Nezara viridula.

The tarsal attachment devices of the southern green stink bug Nezara viridula, a cosmopolitan pest of different crops, encompass a pair of claws, distal pretarsal smooth pulvilli, and a proximal hairy pad on the ventral basitarsus. To evaluate the role of these attachment devices in generating attachment, behavioural experiments testing locomotion of insects with ablated pulvilli, shaved hairs and cut-off claws were performed. Using traction force experiments, insect attachment performance was evaluated on artificial substrates characterised by different roughness and on two substrates with different surface energies in the air and under water. To examine the contact area of attachment devices during resting, pulling and inverted walking, intact insects and those without claws were video-recorded using a high-speed camera. The present data reveal a great involvement of pulvilli in insect attachment on all the tested surfaces, while the hairy pad seems to have a role in producing friction forces only on smooth surfaces and on surfaces with intermediate roughness. The hairy pad was revealed to be important in adhesion to hydrophobic substrates under water, a function that could be relevant for N. viridula insects in consideration that many plant leaves tend to have hydrophobic surfaces and may be often covered by water film.

Pedestrian injury severity in the event of a collision with a truck: are energy absorbing adaptive deformable fronts suitable

It is well known that adaptive deformable fronts attached to trucks reduce pedestrian injury. However, the suitability of these frontal attachment devices from a holistic point of view, considering both primary and secondary impacts, is questioned in this paper. Using head-injury-criteria index, the effects of pedestrian gait and different closing speeds are considered for evaluation of numerous truck-pedestrian side and rear impact situations. Numerical simulations, considering coupled rigid and deformable-body dynamics, have been carried out in this paper to arrive at conclusions. For primary side impact scenario DEA frontal attachment provides a performance improvement specifically for 0% gait; however, the performance improvement is non-uniform for other gait cycles. For primary rear impact scenarios, it is observed that DEA is not a useful alternative at all. For secondary collision scenarios (involving both side and rear impacts) DEA is not at all an effective means for performance improvement.

Scaling of claw sharpness: mechanical constraints reduce attachment performance in larger insects.

Claws are the most widespread attachment devices in animals, but comparatively little is known about the mechanics of claw attachment. A key morphological parameter in determining attachment ability is claw sharpness; however, there is a conflict between sharpness and fracture resistance. Sharper claws can interlock on more surfaces but are more likely to break. Body size interacts with this conflict such that larger animals should have much blunter claws and consequently poorer attachment ability than smaller animals. This expected size-induced reduction in attachment performance has not previously been investigated, and it is unclear how animals deal with this effect, and whether it indeed exists. We explored the scaling of claw sharpness with body size using four insect species (Nauphoeta cinerea, Gromphadorhina portentosa, Atta cephalotes and Carausius morosus) each covering a large size range. The scaling of claw sharpness varied significantly between species, suggesting that they face different pressures regarding claw function. Attachment forces were measured for A. cephalotes and G. portentosa (which had different scaling of claw sharpness) on several rough surfaces using a centrifuge setup. As expected, attachment performance was poorer in larger animals. Firstly, larger animals were more likely to slip, although this effect depended on the scaling of claw sharpness. Secondly, when they gripped, they attached with smaller forces relative to their weight. This size-induced reduction in attachment performance has significant implications for the attachment ability of larger animals on rough surfaces.

Pedestrian injury severity in the event of a collision with a truck: are energy absorbing adaptive deformable fronts suitable

It is well known that adaptive deformable fronts attached to trucks reduce pedestrian injury. However, the suitability of these frontal attachment devices from a holistic point of view, considering both primary and secondary impacts, is questioned in this paper. Using head-injury-criteria index, the effects of pedestrian gait and different closing speeds are considered for evaluation of numerous truck-pedestrian side and rear impact situations. Numerical simulations, considering coupled rigid and deformable-body dynamics, have been carried out in this paper to arrive at conclusions. For primary side impact scenario DEA frontal attachment provides a performance improvement specifically for 0% gait; however, the performance improvement is non-uniform for other gait cycles. For primary rear impact scenarios, it is observed that DEA is not a useful alternative at all. For secondary collision scenarios (involving both side and rear impacts) DEA is not at all an effective means for performance improvement.

Methods to measure the mechanical behaviour of tree roots: A review

The presence of forests on hillslopes significantly reduces the slopes susceptibility to rainfall triggered shallow landslides. This is due largely to the reinforcement of the hillslope soil by tree roots which increase the shear strength of the soil, and in some instances, anchor the soil mantle to the underlying bedrock by deeply penetrating roots. Quantifying the reinforcing effects of tree roots within soils and the evaluation of hillslope stability using geomechanical and numerical models relies on a realistic representation of the characteristics of tree roots distribution within the hillslope and the mechanical strength of those roots. The variety of experimental methods that have been developed since the 1960s and are used to generate these root strength and rooted-soil shear-strength data are reviewed. The majority of these studies have focused on determining the tensile strength of individual roots by loading the root in a pulling device until it breaks and/or determining the shear-strength of rooted soil in comparison to non-rooted soil in a Coulomb-type shear-box test. These studies have also generally either examined mature root systems in the field or relatively young plants grown in special containers specifically designed for tensile tests or laboratory shear-box tests. A particular difficulty that most studies have encountered is fixing or securing the ends of roots in the attachment device of the testing apparatus (so called root-pullers or tensile testing machines) as the various styles of clamping employed can easily damage the root which reduces the measured strength or otherwise results in an unrealistic test result. Laboratory shear-box tests encounter a similar difficulty in that the roots are not generally fixed or constrained at the base of the shear-box; field shear-box tests tend to avoid this problem as the roots are present in their natural anchoring characteristics in the soil and rock substrate. A result universally reported in rooted soil shear-box test studies is that the peak shear-strength of rooted soil significantly exceeds the peak shear-strength of that soil in a non-rooted condition and that the rooted-soil peak strength is typically recorded at a shear-displacement distance several times that of the non-rooted soil. This result fundamentally explains the reduced susceptibility of forested hillslopes to shallow landslides. A variety of solutions developed to deal with the difficulties that root and rooted-soil tests present are outlined. A set of suggested protocols for conducting root tensile tests and field pullout tests are also presented. It is intended that the adoption of these protocols will enable more effective and direct comparisons of test results and more confident interpretation with respect to the similarities and differences between test results generated from different species and field sites.

Biomechanical analysis of the posterior bony column of the lumbar spine

BackgroundEach part of the rear bone structure can become an anchor point for an attachment device. The objective of this study was to evaluate the stiffness and strength of different parts of the rear lumbar bone structure by axial compression damage experiments.MethodsFive adult male lumbar bone structures from L2 to L5 were exposed. The superior and inferior articular processes, upper and lower edges of the lamina, and upper and lower edges of the spinous process were observed and isolated and then divided into six groups (n = 10). The specimens were placed between the compaction disc and the load platform in a universal testing machine, which was first preloaded to 5.0 N tension to eliminate water on the surface and then loaded to the specimen curve decline at a constant tension loading rate of 0.01 mm/s, until the specimens had been destroyed.ResultsSignificant differences in mechanical properties were found among different parts of the rear lumbar bone structure. Compared with other parts, the lower edge of the lamina has good mechanical properties, which have a high modulus of elasticity; the superior and inferior articular processes have greater ultimate strength, which can withstand greater compressive loads; and the mechanical properties of the spinous process are poor, and it is significantly stiffer and weaker than the lamina and articular processes.ConclusionThese data can be useful in future spinal biomechanics research leading to better biomechanical compatibility and provide theoretical references for spinal implant materials.

Strongest grip on the rod: tarsal morphology and attachment of Japanese pine sawyer beetles

Plant-dwelling beetles overcome challenging attachment hurdles by means of ellaborated, tarsal attachment devices, which are frequently equipped with hairy adhesive pads. While the tarsal functional morphology has been intensively studied in leaf and ladybird beetles during the last decades, longhorn beetles (Cerambycidae) have been widely neglected in experimental studies on insect attachment. However, they are known to strongly hold on to plant substrates, using tarsi that are densely covered with adhesive setae. In the present study, we examined the Japanese pine sawyer beetle, Monochamus alternatus, which lives in an arboreal habitat, as an exemplary case. Traction force of male and female beetles on (1) flat and (2) cylindrical, rod-shaped glass was measured. The substrates are further called (1) glass plate and (2) glass rod.Both male and female M. alternatus bear ribbon-shaped tarsal adhesive setae with broadened, ultrathin terminals. They release a distinct amount of adhesion-mediating fluid after each step. The beetles never walked on the vertically oriented glass plate. However, they performed well on the horizontal plate, as well as on the horizontally and vertically oriented glass rod. Males generated higher forces and safety factors (traction force devided by the body weight) than females, reaching up to 206 mN traction force and a safety factor of 32 on the horizontal glass rod. Thus, they are able to carry their remarkable body weight (ca. 300 mg) throughout a rather long life span.We assume the adaptation of M. alternatus to the attachment on convex and rod-shaped structures to be present in its natural habitat. This longhorn beetle species achieves a proper hold through a combination of interacting parameters: appropriate body alignment and two-sided leg grasping, and generation of normal and friction forces by tarsal pads. This smart attachment system gives rise to the reconsideration of the ecological and evolutionary background, and provides insights for the development of bio-inspired technical grippers.

Vacuum Control in the Surface Attaching Devices of the Mobile Robots during their Movement under the Aerodynamic Attachment Force

During the movement of the horizon mobile robots over different complex ferromagnetic and non-ferromagnetic surfaces, like walls, ceilings or slopes of various angles, their contacts with the surfaces can be realized by the attaching devices, which ensure an aerodynamic attachment force due to creation of vacuum. In industrial robotics such devices are designed for grasping objects with manipulators on the assembly lines. In the mobile robotics such devices are suitable for creation of an attachment force for the robots. The control system provides an aerodynamic attachment force due to control of the pressure level inside the vacuum area. This ensures adaptation for the mobile robots moving over the surfaces with different quality parameters. This paper describes creation of vacuum with a centrifugal pump and a turbine. It also presents an attachment device based on a centrifugal pump or a turbine, which can create an aerodynamic attachment force for movement of a mobile robot over the sloped surfaces. The air pressure inside the turbine depends on the shape of the blades, the air density and the circumferential speed of the blades. The air pressure created by the centrifugal pump or the turbine is proportional to the blades' rotary speed squared. The dependence of the air pressure on the air flow is obtained. This ensures calculation of the attachment force for the control system of a mobile robot. Simultaneous solving of the equations presented in this paper for the air pressure and the air flow provides an opportunity to obtain the operating modes for different types of the vacuum devices based on a centrifugal pump or a turbine. A possibility of the aerodynamic attachment force control by varying of the gap between the mobile robot and the surface is analyzed. Various parameters of air, such as density, average velocity and flow rate, are discussed. Creation of vacuum inside the vacuum area is considered. The experimental results concerning the pressure control, the attachment force and vacuum creation are presented.

Finger-attachment device for the feedback of gripping and pulling force in a manipulating system for brain tumor resection.

Development and evaluation of an effective attachment device for a bilateral brain tumor resection robotic surgery system based on the sensory performance of the human index finger in order to precisely detect gripping- and pulling-force feedback. First, a basic test was conducted to investigate the performance of the human index finger in the gripping- and pulling-force feedback system. Based on the test result, a new finger-attachment device was designed and constructed. Then, discrimination tests were conducted to assess the pulling force and the feedback on the hardness of the gripped material. The results of the basic test show the application of pulling force on the side surface of the finger has an advantage to distinguish the pulling force when the gripping force is applied on the finger-touching surface. Based on this result, a finger-attachment device that applies a gripping force on the finger surface and pulling force on the side surface of the finger was developed. By conducting a discrimination test to assess the hardness of the gripped material, an operator can distinguish whether the gripped material is harder or softer than a normal brain tissue. This will help in confirming whether the gripped material is a tumor. By conducting a discrimination test to assess the pulling force, an operator can distinguish the pulling-force resistance when attempting to pull off the soft material. Pulling-force feedback may help avoid the breaking of blood pipes when they are trapped in the gripper or attached to the gripped tissue. The finger-attachment device that was developed for detecting gripping- and pulling-force feedback may play an important role in the development of future neurosurgery robotic systems for precise and safe resection of brain tumors.

Functional morphology of tarsal adhesive pads and attachment ability in ticks Ixodes ricinus (Arachnida, Acari, Ixodidae).

The presence of well-developed, elastic claws on ticks and widely pilose hosts led us to hypothesise that ticks are mostly adapted to attachment and locomotion on rough, strongly corrugated and hairy, felt-like substrates. However, by using a combination of morphological and experimental approaches, we visualised the ultrastructure of attachment devices of Ixodes ricinus and showed that this species adheres more strongly to smooth surfaces than to rough ones. Between paired, elongated, curved, elastic claws, I. ricinus bears a large, flexible, foldable adhesive pad, which represents an adaptation to adhesion on smooth surfaces. Accordingly, ticks attached strongest to glass and to surface profiles similar to those of the human skin, generating safety factors (attachment force relative to body weight) up to 534 (females). Considerably lower attachment force was found on silicone substrates and as a result of thanatosis after jolting.

Attachment ability of the southern green stink bug Nezara viridula (Heteroptera: Pentatomidae).

The present paper characterizes the attachment ability of males and females of Nezara viridula (Heteroptera: Pentatomidae) on artificial surfaces (smooth hydrophilic, smooth hydrophobic, different surface roughness) and on both leaf surfaces of the typical host plant species Vicia faba, using a centrifugal force tester and a traction force experiments set up. N. viridula is a serious crop pest in the world and shows attachment devices different from the so far investigated Heteroptera, with a tarsus characterized by distal smooth flexible pulvilli combined with claws and proximal ventral hairy pad. Notwithstanding the different body mass between the sexes, no difference was found between friction forces generated by females and males. Friction force was higher on hydrophilic surfaces than on hydrophobic ones and was lower on both sides of V. faba leaf compared with both hydrophilic and hydrophobic artificial smooth surfaces. On the surfaces with different roughness, the friction force values varied significantly, with the higher attachment ability on the surface with very high asperity size followed by the smooth surface. The lowest attachment was on the surfaces with intermediate asperity sizes. These results could be related to the specific combination of attachment devices of N. viridula.

Attachment of honeybees and greenbottle flies to petal surfaces

Flower surfaces play a key role in the interaction with pollinators acting as signals and landing sites to attach to. To test attachment, Carniolan honeybees and greenbottle flies were used. Both species represent pollinators equipped with smooth or hairy tarsal attachment devices, respectively. A combination of microscopic methods and traction force measurements was applied in order to understand and evaluate the efficiency of pollinator attachment to a variety of petal surfaces. Although the petal surface texture influenced the attachment, coevolutionary relationships or adaptations between flower surfaces and pollinator tarsi could not be confirmed. Since pollinators appear to be opportunistic, they are expected to attach to a variety of flower surfaces. Rougher surfaces, including conical and papillate epidermal cells, significantly increased the foothold of flies and honeybees, while flat, tabular epidermal cells covered with microstructures like cuticular folds and epicuticular wax crystals impaired attachment. Carniolan honeybees generated larger forces than greenbottle flies, but the latter showed higher safety factors. However, tendencies in attachment ability toward sufficient and insufficient substrates are similar in flies and bees.

Inexpensive Attachment Device for Cell Therapy Administration into Injured Spinal Cord

Cell therapy is configured as a promising strategy for the treatment of spinal cord injury (SCI), but it requires reliable systems to achieve microinjections with different rates and volumes, according to the different characteristics of the injured spinal cord tissue and the targets previously selected. We sought to describe an original and inexpensive device for support of microinjection systems in the course of spinal cord surgery. Our attachment device consists of an arch and a system of bars that can be fixed to the operating table and on which a microinjection pump can be displaced and fixed in the course of surgery. This device has been used for therapy administration into injured spinal cords. It is easy to use and permits reproducible results. We have described an original attachment device for the support of a microinjection pump. It is applicable to spinal cord surgery and should be considered as a cheap solution for intralesional administration of cell therapy after spinal cord injury.