Spider Leg Research Articles

Enhanced In‐Plane Omnidirectional Energy Harvesting from Extremely Weak Magnetic Fields via Fourfold Symmetric Magneto‐Mechano‐Electric Coupling

AbstractMagneto‐mechano‐electric (MME) energy harvesters (EHs) have emerged as a promising solution for powering Internet of Things (IoT) sensor networks by capturing ambient stray magnetic fields in urban circumstance. Despite significant advancements, achieving milliwatt‐level power generation from extremely weak (<1 Oe) and randomly oriented magnetic fields remains challenging. Drawing inspiration from the configuration of cross‐shaped spider legs, this study introduces an innovative X‐shaped MME‐EH featuring fourfold symmetric architecture with symmetrically distributed magnets at each end, enabling near‐isotropic in‐plane omnidirectional energy harvesting. Under extremely weak magnetic fields 0.75 and 0.3 Oe at 60 Hz, the device achieves a record‐high output power of 7.31 and 1.67 mWRMS, respectively, representing a 362% improvement in normalized power over the state‐of‐the‐art results. The theoretical model attributes these gains to the synergistic enhancement effect of the second bending mode and the dual‐mode structure, collectively improving both magnetomechanical and electromechanical coupling by augmenting the magnetic moments and suppressing the clamp loss. The device further demonstrates robust real‐world applications, efficiently powering a wireless IoT sensor system by harvesting multidirectional magnetic field energy from household appliances. This work opens new avenues for developing efficient multimodal MME‐EHs capable of harnessing omnidirectional, weak magnetic fields for widespread IoT applications.

Change of Adhesion Properties of Bioinspired Laser-Induced Periodic Nanostructures towards Cribellate Spider Nanofiber Threads by Means of Thin Coatings

We investigated the effect of additional continuous functional coatings, which changed the hydrophilic–hydrophobic properties of the surface without heavily influencing the surface topography at the nanoscale, on the antiadhesive properties of bioinspired laser-induced periodic nanostructures. These nanostructures mimic the antiadhesive structures on the silk-combing area on the legs of cribellate spiders, the calamistrum. The thin films were deposited by matrix-assisted laser deposition and characterized by infrared spectroscopy, X-ray photoelectron spectroscopy, water contact angle measurements, and adhesion tests using capture threads from the cribellate spider webs. In all cases, the nanoripples were preserved and these structured surfaces showed lower adhesion forces compared to flat controls, although not significant. However, this effect was totally overwhelmed by the difference between the adhesion forces on surfaces with different chemical compositions. The largest adhesion forces were observed on hydrophilic surfaces and the lowest ones on hydrophobic surfaces. The fact that the antiadhesion between nanofibers and the nano-structured areas depends strongly on the chemical composition of the surface can be explained by the specific adhesion between individual chemical groups due to frequency dependencies in the theory of van der Waals forces. However, explaining these adhesion properties just by the categories “hydrophilic” or “hydrophobic” is oversimplified.

Highly Sensitive Biomimetic Crack Pressure Sensor with Selective Frequency Response.

High-sensitivity sensors in practical applications face the issue of environmental noise interference, requiring additional noise reduction circuits or filtering algorithms to improve the signal-to-noise ratio (SNR). To address this issue, this study proposes a biomimetic crack pressure sensor with selective frequency response based on hydrogel dampers. The core of this research is to construct a biomimetic crack pressure sensor with selective frequency response using the high-pass filtering characteristics of gelatin-chitosan hydrogels. This design, inspired by the slit sensilla and stratum corneum structure of spider legs, delves into the material properties and principles of hydrogel dampers, exploring their application in biomimetic crack pressure sensors, including parameter selection, structural design, and performance optimization. By delving into the nuanced characteristics and working principles of hydrogel dampers, their integration in biomimetic crack pressure sensors is examined, focusing on aspects like parameter selection, structural engineering, and performance enhancement to selectively sieve out low-frequency noise and transmit target vibrational signals. Experimental results demonstrate that this innovative sensor, while suppressing low-frequency vibration signals, can selectively detect high-frequency signals with high sensitivity. At different vibration frequencies, the relative change in resistance exceeds 200%, and the sensor sensitivity is 7 × 104 kPa-1. Furthermore, this sensor was applied to human voice detection, and the corresponding results verified its frequency-selective performance evidently. This study not only proposes a new design for pressure sensors but also offers fresh insights into the application of biomimetic crack pressure sensors in intricate environments.

5G NB-IoT System Integrated with High-Performance Fiber Sensor Inspired by Cirrus and Spider Structures.

Real-time telemedicine detection can solve the problem of the shortage of public medical resources caused by the coming aging society. However, the development of such an integrated monitoring system is hampered by the need for high-performance sensors and the strict-requirement of long-distance signal transmission and reproduction. Here, a bionic crack-spring fiber sensor (CSFS) inspired by spider leg and cirrus whiskers for stretchable and weavable electronics is reported. Trans-scale conductive percolation networks of multilayer graphene around the surface of outer spring-like Polyethylene terephthalate (PET) fibers and printing Ag enable a high sensitivity of 28475.6 and broad sensing range over 250%. The electromechanical changes in different stretching stages are simulated by Comsol to explain the response mechanism. The CSFS is incorporated into the fabric and realized the human-machine interactions (HMIs) for robot control. Furthermore, the 5G Narrowband Internet of Things (NB-IoT) system is developed for human healthcare data collection, transmission, and reproduction together with the integration of the CSFS, illustrating the huge potential of the approach in human-machine communication interfaces and intelligent telemedicine rehabilitation and diagnosis monitoring.

Diet Affects Egg Laying, Biomass, and Stable Isotope Values in Tetragnathid Spiders.

Riparian tetragnathid spiders are used as biosentinels of aquatic contamination because they are specialized feeders of aquatic emergent insects and are also prey items for terrestrial predators (e.g., birds). Analysis of both trophic position (e.g., stable nitrogen isotopes) and contaminant concentrations are needed to utilize tetragnathids as biosentinels, which can present challenges when collecting enough biomass to reach analytical detection limits, due to their relatively small size. The purpose of this study was to investigate the impacts of a controlled diet source on spider biomass, egg laying and stable isotope values (δ13C and δ15N). Diet significantly influenced the biomass and egg laying of tetragnathids, with some spiders losing up to 50% of their biomass in a single egg-laying event. δ13C had a faster turnover rate in the whole-body of spiders compared to legs, which is important, as spider legs are presently used as surrogates for whole-body δ13C values.

Corrugated V-fold soft actuator with large deformation and high force density

Soft pneumatic actuators with a corrugated structure have the advantage of low inflation pressure and a large actuation range and have great potential for use in grippers. However, they are generally difficult to have both large deformation and high force density performance. Inspired by the hydraulic joints of spider legs, this paper designs a multi-cavity soft-pneumatic actuator with a corrugated V-fold structure, which realizes bending through the deformation of the air cavity structure instead of the traditional way of squeezing the air cavities against each other, and has significantly large curvature high force density compared with actuators such as PneuNets. At an inflation pressure of 40 kPa, the proposed soft actuator achieves a bending angle of 306° with a curvature of 0.114 rad mm−1, while at an inflation pressure of 45 kPa, the actuator achieves an actuation force of 5.15 N with a force density of 0.0101 mN (mm3.kPa)−1. The modeling approach based on continuum mechanics modeling of soft materials combined with finite element analysis (FEA) (or experiment) is proposed to achieve accurate modeling of the bending angle and actuation force of actuators with complex corrugated structures. In addition, the proposed actuator has made initial explorations into the application of soft grippers and has achieved fairly good gripping results compared to other types of grippers.

Fabrication of a spider-legged agricultural spraying and grass cutting robot using Klann-mechanism with green energy-based obstacle detection

The most effective leg processes resembling a spider leg are currently, Joe Klan system, and the Jansen mechanism, which also resembles a human leg. Owing to more practicality and effectiveness, Joe Klan's approach was prioritized. The wheel has been the fundamental element used in all forms of mechanical conveyance since its inception in the Stone Age. However, because of short-term development effects on things like small staircases, obstacles, agricultural regions, and steep, jagged rock piles, wheels have always had significant downsides. Designers contemplate on animal and human legs as a solution to these issues. The present study's major objective is to develop a replacement for the purpose of wheels utilized for seeding, spraying, and removing the grass in order to address the problems which move through agricultural areas. In addition to assemble the pieces that are already on the market, the robot may be remotely directed to cut the grass in an agricultural region.

A Spider-Joint-like Bionic Actuator with an Approximately Triangular Prism Shape.

The unique drive principle and strong manipulation ability of spider legs have led to several bionic robot designs. However, some parameters of bionic actuators still need to be improved, such as torque. Inspired by the hydraulic drive principle of spider legs, this paper describes the design of a bionic actuator characterized by the use of air pressure on each surface and its transmittance in the direction of movement, achieving a torque amplification effect. The produced torque is as high as 4.78 N m. In addition, its torque characteristics during folding motions are similar to those during unfolding motions, showing that the bionic actuator has stable bidirectional drive capability.

Study on Diversity of Fungus Associated with Nephila pilipes

The fungus has various type of association with spider. They can be pathogenic or symbiotic or commensal in relationship to spiders they live on. In the current study the diversity of fungi in association with Nephila pilipes spider were recorded. The fungi were isolated from its legs and saliva. The microscopic and macroscopic characters were obtained. The measurements of hyphae, conidia and conidiophore were recorded. The fungal growth was more on legs compared to saliva. The legs of the adult spider carried more fungi than saliva as they are associated with soil, carrying microflora on their legs. Further the four different fungus isolated as aspergillus, penicillium, Trichoderma and Cladosporium. The penicillium colony had abundant growth, aspergillus had moderate growth and Cladosporium had less growth compared to Trichoderma.

Chinese TikTok (Douyin) challenges and body image concerns: a pilot study

BackgroundSocial media content on Western platforms promoting thinness, or thinspiration, has been found to negatively affect body image perception of users. Less is known about non-Western social media use and its effects on body image concerns. Chinese TikTok, known as Douyin, is a popular short video platform with 600 million daily active users. Recent trends on Douyin encourage users to demonstrate thinness through participation in ‘body challenges’. This paper argues that such content is comparable to thinspiration, however, to date hardly any research has been undertaken on these challenges. Thus, this pilot study aimed to analyse the content of three viral challenges and investigate their impact on Douyin users.MethodsThirty most viewed videos were collected for three challenges (N = 90): the Coin challenge, the A4 Waist challenge, and the Spider leg challenge. Videos were coded for variables relating to thin idealisation, including thin praise, sexualisation and objectification, and analysed through content analytic methods. Video comments (N ≈ 5500) were analysed through thematic analysis, and main themes were identified.ResultsPreliminary findings showed that participants who objectified their bodies to a greater extent expressed more negative body image concerns. In addition, comments on the videos had themes of thin praise, self-comparison, and promotion of dieting behaviours. In particular, videos of the A4 Waist challenge were found to incite more negative self-comparison in viewers.ConclusionPreliminary findings suggest all three challenges promote the thin ideal and encourage body image concerns. Further research about the broader impact of body challenges is needed.

Developing multifunctional and environmental-friendly hot-pressed peanut meal protein adhesive based on peanut waste

Hot-pressed peanut meal protein (HPMP) adhesives showed great potential as an alternative to formaldehyde-based adhesives because of their renewability and environmental-friendly, but their practical applications are severely limited by the poor bonding strength, water resistance and anti-mildew properties. Inspired by the spider leg structure, the functional graded peanut shell fiber (Ag/ZnO@APSF) loaded with metal nanoparticles was constructed through the biomineralization strategy as mineralized skeleton; Luteolin Epoxide (LE) as crosslinking agent. We had developed a green strategy for fabricating a novel HPMP adhesive with strong water resistance, high bonding strength, and strong mold resistance was prepared through a steel bars-concrete network structure using peanut waste, Ag/ZnO@APSF and LE. Compared with pure HPMP adhesive, the dry shear strength and wet shear strength of adhesive increased by 114% (2.29 MPa) and 257.9% (1.36 MPa), respectively. The residual rate increased by 43.8%, the moisture absorption rate and viscosity decreased by 48% and 45.4%, respectively. The adhesive had excellent flame retardancy with a reduction of 35.2% in peak heat release rate and 28.4% in total heat release rate, respectively. The antimildew time increased from 1 d to more than 45 d. In addition, the HPMP adhesive exhibited long-term adhesion behavior (pot life of 14 d), the pre-pressing bonding strength increased by 175.7% (1.02 MPa). This strategy had enhanced the added value of peanut waste and contributed to the development of multifunctional new plant protein adhesives.

Pneu-HTP based extrusion actuation in bio-inspired soft joint

Inspired by the joint structure and actuation mechanism of spider legs, a novel pneumatic soft joint actuator is designed, which achieves joint rotation by mutual compression of two hyperelastic sidewalls under inflation pressure. For this type of extrusion actuation, a pneumatic hyperelastic thin plate (Pneu-HTP) based actuation modeling method is proposed. The two actuating surfaces extruded mutually of the actuator are considered as Pneu-HTPs, and mathematical models for their parallel extrusion actuation and angular extrusion actuation are derived. The finite element analysis (FEA) simulations and experiments were also performed to evaluate the model accuracy of the Pneu-HTP extrusion actuation. The results for the parallel extrusion actuation show that the average relative error between the proposed model and the experiment is only 9.27%, and the goodness-of-fit is greater than 99%. For the angular extrusion actuation, the average relative error between the model and the experiment is 12.5%, and the goodness-of-fit is greater than 99%. The parallel extrusion actuating force and rotational extrusion actuating force of the Pneu-HTP are also highly consistent with the FEA simulation results, which provides a promising method for the accurate modeling of extrusion actuation in soft actuator.

Spatial selectivity by shaping the static field: sweet spots and spider legs

Spatial selectivity by shaping the static field: sweet spots and spider legs

Sensory Structures on the Antenniform Legs of Whip Spider, Phrynichus phipsoni (Arachnida, Amblypygi), from the Indian State of Goa: Scanning Electron Microscopic Elucidation

Amblypygi have a tropical and sub-tropical distribution and their first of the four pairs of legs, is modified as feelers. Their activity period and dark habitats render visual cues ineffective and they rely on non-visual sensory perception. There is agreement among researchers that the whip spiders invest in olfactory and tactile senses imparted by sensory structures concentrated on the tarsal segment of the first pair of long, well-articulated non-ambulatory legs that are constantly moved in all directions to sample the environment for detecting location of prey, as also for navigating. This is the first attempt to elucidate the sensory structures present on the antenniform legs of the whip spider, Phrynichus phipsoni (Pocock, 1894), collected from the state of Goa, India; using scanning electron micro[1]scope, and paves way for further research on sensory biology of this cryptic arachnid order. The examined specimen generally conforms to the diversity and morphology of sensory assemblage on the antenniform legs reported in other amblypygi species. Sensory structures elucidated include terminal trident tarsal claws, tarsal organ, bristles, porous sensilla, club sensilla, rod sensilla, slit sensilla, trichobothria, plate organ, pit organ and foliate leaf like hairs.

Laser-processed antiadhesive bionic combs for handling nanofibers inspired by nanostructures on the legs of cribellate spiders.

Nanofibers are drawing the attention of engineers and scientists because their large surface-to-volume ratio is favorable for applications in medicine, filter technology, textile industry, lithium-air batteries, and optical sensors. However, when transferring nanofibers to a technical product in the form of a random network of fibers, referred to as nonwoven fabric, the stickiness of the freshly produced and thus fragile nanofiber nonwoven remains a problem. This is mainly because nanofibers strongly adhere to any surface because of van der Waals forces. In nature, there are animals that are actually able to efficiently produce, process, and handle nanofibers, namely cribellate spiders. For that, the spiders use the calamistrum, a comb-like structure of modified setae on the metatarsus of the hindmost (fourth) legs, to which the 10-30 nm thick silk nanofibers do not stick due to a special fingerprint-like surface nanostructure. In this work, we present a theoretical model of the interaction of linear nanofibers with a sinusoidally corrugated surface. This model allows for a prediction of the adhesive interaction and, thus, the design of a suitable surface structure to prevent sticking of an artificially nonwoven of nanofibers. According to the theoretical prediction, a technical analogon of the nanoripples was produced by ultrashort pulse laser processing on different technically relevant metal surfaces in the form of so-called laser-induced periodic surface structures (LIPSS). Subsequently, by means of a newly established peel-off test, the adhesion of an electrospun polyamide fiber-based nonwoven was quantified on such LIPSS-covered aluminium alloy, steel, and titanium alloy samples, as well as on polished (flat) control samples as reference and, additionally, on samples with randomly rough surfaces. The latter revealed that the adhesion of electrospun nanofiber nonwoven is significantly lowered on the nanostructured surfaces compared with the polished surfaces.

Fiber-reinforced flexible joint actuator for soft arthropod robots

The flexible joints are the fundamental building blocks of modular soft robots. However, the investigation on flexible joints made entirely of soft material is still in its infancy, with complex structure, small rotation range and insufficient driving force output. Bio-inspired from the hydraulic joints of spider legs, a dexterous fiber-reinforced flexible joint actuator was proposed. For the irregular shape joint actuator with fiber-reinforced structure, its fabrication process and modeling method are discussed. And the advantages of fiber reinforcement are demonstrated in terms of rotation angle, driving torque and efficiency experiments. Compared with the joint actuator without fiber layer, the actuator with a fiber angle of 30° can increase the rotation angle by up to 36% and the driving efficiency by up to 19.6%. The maximum inflation pressure can reach 120 kPa, and the force density 3.56 mN/mm3, which demonstrates extremely high pressure tolerance capacity and force density, and shows the wide applicability of the fan-shaped flexible actuator to enable lightweight, mobile, multifunctional soft robots.

Greater than the sum of your parts: Nonlethal stable isotope sampling methods in spiders

AbstractAs top consumers and generalist predators, spiders are ideal organisms to study food webs and complex ecological functions using stable isotopes. Most researchers use whole‐body samples to analyze stable isotope ratios in spiders. Spiders can regrow lost legs and produce multiple molts during a life cycle, and nonlethal sampling utilizing legs and molts may provide a useful alternative to whole‐body sampling especially in larger bodied or threatened species. Furthermore, removing spider abdomens and thus leftover prey in the gut contents may provide a more accurate isotopic value. We tested the hypothesis that the δ15N, δ13C, or δ2H isotopic values in spider legs are reliable proxies for spider prosomas, abdomens, or whole bodies. We used laboratory‐reared large‐bodied spiders (Pterinochilus murinus) and field‐collected Lycosidae to compare lethal and nonlethal tissue isotopic values. We found that nonlethal samples of spider legs and molts are acceptable alternatives to lethal whole‐body samples to determine δ13C and δ15N stable isotope signatures. Nonlethal samples are not suitable proxies for whole‐body samples to determine δ2H isotopic values. Using nonlethal leg or molts samples in stable isotope investigations of spiders will allow researchers to promote conservation efforts and study threatened species while ensuring accurate and repeatable results.

Skin-Driven Ultrasensitive Mechanoluminescence Sensor Inspired by Spider Leg Joint Slits.

Inspired by the spider's slit organ embedded in the leg joint exoskeleton and its ultrasensitive stress perception, we propose to fix the conflict between the stress concentration requirement for bright mechanoluminescence (ML) and the stress dispersion effect of soft material via integrating slit microstructures into flexible films. The designed slits focus weak stresses onto the corner to achieve high sensitivity, leading to 10-30 times ML intensity improvement at weak strain (<10% stretch) application. Slit morphology and various patterns were well investigated to address the stress distribution regularity. The slit-based ML film offers a facile light-luminescent artificial skin for visualizable stress presentations or detections without electricity power source. It is a practical endeavor of photonic skin for visible vocalization and a significant contribution to dysaudia auxiliary or luminescence augmented expressions for human social interactions, similar to jellyfish or squids.

Permanent deformation of triangle weaver silk enables ultrafast tangle-free release of spider webs.

Entanglements are common in both natural and artificial systems and can result in both beneficial and harmful effects. Most spider webs are static structures held under constant tension and do not tangle. However, many spiders actively load tension into their webs by coiling silk threads that are released to "fire" webs at prey. Here we test whether or not tangling occurs during the rapid release of webs built by the triangle spider Hyptiotes cavatus. We use high-speed videography to examine the release of the spider's web, looking for signs of tangling both visually on the videos and on acceleration graphs. The spider tenses the web by pulling on a silken anchor line using a leg-over-leg movement, deforming the silk into permanent coils and storing excess slack in a loose bundle between the spider's legs. This 1-3cm long bundle of coils straightens during the web's release in as few as 4ms. Though the messy silk coils are pressed closely together, the web's release is never impeded by catastrophic tangling. This lack of serious tangling is perhaps due to the permanent coils preventing random movement of the silk. The coils also compact the loose silk, preventing interference with the spider's movement. The ability to coil its anchor line allows H. cavatus to permanently restructure its silk, facilitating its active web-hunting behavior. Our findings broaden our knowledge of silk manipulation by spiders and may give insights into creating tangle-free systems through structural changes.

Pulmonary actinomycosis: cytomorphological features.

Pulmonary actinomycosis is an uncommon infectious disease. Although the gold standard for diagnosis is histological examination with bacterial culture of lung tissue, cytology samples offer a fast and low-cost alternate diagnostic procedure. The cytology literature on this topic is limited to mostly case reports. Therefore, the aim of this study was to review cytological material in a series of patients with a diagnosis of pulmonary actinomycosis to characterize the main cytomorphological findings. Different cytological respiratory samples including sputum smears, bronchoalveolar lavages (BALs), transthoracic or endobronchial fine needle aspiration cytology (FNAC) and cell block preparations were used for retrospective examination. For all cases patient age, gender, symptoms, and radiological chest findings were recorded. A total of 26 cytological respiratory samples (14 sputum smears, 9 FNAC, two BALs) including direct smears and 6 cell blocks from 9 patients were examined. In sputum smears the most remarkable findings were the presence of dark cotton ball masses with projections like spider legs and/or mouse tails (75% of the samples). Sulfur granules were observed in 4 (40%) of the sputum smears and within FNAC cases. Various respiratory cytology samples including sputum smears, FNAC and BALs can reveal cytomorphological findings diagnostic of pulmonary actinomycosis. Characteristic cytological findings compatible with a diagnosis of this infection include cotton ball masses and less frequently sulfur granules.