Search Results (81)

We identified Murashka, a RING finger protein, in an oogenesis screen as a regulator of Drosophila ovary germline stem cell niche development. Mutant alleles of murashka exhibited an enlarged niche phenotype reminiscent of increased Notch signalling and displayed genetic interactions with Notch alleles, and with polychaetoid, a regulator of Notch during niche development. These interactions uncovered both positive and negative impacts on Notch in different genetic backgrounds. In S2 cells, Murashka formed a complex with Notch and colocalised with Notch in the secretory pathway. Murashka expression in S2 cells down-regulated Notch signalling levels but could result in increased fold induction due to the proportionally greater decrease in basal ligand-independent activity. In vivo Murashka expression had different outcomes on different Notch target genes. We observed a decrease in the expression of vestigial along the anterior/posterior boundary of the wing imaginal disc, but not of wingless at the dorsal/ventral boundary. Instead, weak ectopic wingless was observed, which was synergistically increased by the coexpression of Deltex, a positive regulator of ligand-independent signalling. Our results identify a novel developmental role for murashka, a gene previously only associated with a function in long-term memory, and indicate a regulatory role for Murashka through a physical interaction with Notch that has context-dependent outcomes. Murashka adds to a growing number of ubiquitin ligase regulators which interact with Notch at different locations within its secretory and endocytic trafficking pathways. Full article

The planthopper Pentastiridius leporinus, commonly called reed glass-winged cicada, transmits the pathogens “Candidatus Arsenophonus phytopathogenicus” and “Candidatus Phytoplasma solani”, which are infesting sugar beet and, most recently, also potato in the Upper Rhine valley area of Germany. They cause the “Syndrome Basses Richesses” associated with reduced yield and sugar content in sugar beet, leading to substantial monetary losses to farmers in the region. No effective solutions exist currently. This study uses statistical models to understand to what extent the abundance of cicadas depends on climate regions during the vegetation period (April–October). We further investigated what influence temperature and precipitation have on the abundance of the cicadas in sugar beet fields. Furthermore, we investigated the possible impacts of future climate on cicada abundance. Also, 22 °C and 8 mm/day were found to be the optimal temperature and precipitation conditions for peak male cicada flight activity, while 28 °C and 8 mm/day were the optimum for females. By the end of the 21st century, daily male cicada abundance is projected to increase significantly under the worst-case high greenhouse gas emission scenario RCP8.5 (RCP-Representative Concentration Pathways), with confidence intervals suggesting a possible 5–15-fold increase compared to current levels. In contrast, under the low-emission scenario RCP2.6, male cicada populations are projected to be 60–70% lower than RCP8.5. An understanding of the influence of changing temperature and precipitation conditions is crucial for predicting the spread of this pest to different regions of Germany and other European countries. Full article

In this paper, a beetle with excellent flight ability and a large folding ratio of its hind wings is selected as the biomimetic design. We mimicked the geometric patterns formed during the folding process of the hind wings to construct a deployable mechanism while calculating the sector angles and dihedral angles of the origami mechanism. In the expandable structure of thick plates, hinge-like steps are added on the thick plate to effectively avoid interference motion caused by the folding of the thick plate. The kinematic characteristics of two deployable mechanisms were characterized by ADAMS 2018 software to verify the feasibility of the mechanism design. The finite element method is used to analyze the structural performance of the deployable mechanism, and its modal response is analyzed in both unfolded and folded configurations. The aerodynamic generation of a spatially deployable wing is characterized by computational fluid dynamics (CFD) to study the vortex characteristics at different frame rates. Based on the aerodynamic parameters obtained from CFD simulation, a wavelet neural network is introduced to learn and train the aerodynamic parameters. Full article

Aim: Endo-Wing™ is a soft silicone device with six wing-like projections attached at the end of the colonoscope that provides superior visualization by flattening the colonic fold and helps to maintain a central view of the colonoscope during withdrawal. This study aims to compare the adenoma detection rate (ADR) between standard colonoscopy and Endo-Wing™-assisted colonoscopy. Methods: This is a single-center, single-blind, parallel-group, randomized, actively controlled, exploratory clinical trial conducted between July 2019 and April 2020. Participants aged 45 and above who were symptomatic of colorectal cancer (CRC) or with a history of adenoma and under active surveillance were included. Exclusion criteria included colonic strictures, tumors, active colitis, a previous history of polyposis syndrome, colostomy/ileostomy, or a BPPS score of 0. Participants were subsequently randomized to receive standard colonoscopy (n = 96) or Endo-Wing™-assisted colonoscopy (n = 96) at a 1:1 ratio using a central block randomization method with varying block sizes. The primary endpoint was the ADR, and the differences between the two groups were evaluated using univariable statistical methods. Results: The ADR, the number of adenomas, and the size of adenomas in the Endo-Wing™-assisted colonoscopy group were significantly higher compared to standard colonoscopy (p = 0.005, 0.035, and 0.035, respectively). Cecal intubation rates were similar in both groups (p > 0.999). The proportions of colonoscopy requiring increased sedation and standard sedation were similar in both groups (p = 0.613). No adverse effects of bleeding, perforation, and device dislodgement were reported in both groups. Conclusions: This study concludes that Endo-Wing™-assisted colonoscopy improves the ADR compared to standard colonoscopy. Full article

This study investigates the aerodynamic effects of wing membrane elasticity inspired by bats, which exhibit exceptional maneuverability and stability. By mimicking bat wing folding and flapping motions, a 2-DOF flapping mechanism was developed to examine the impact of wing membrane elasticity. Polydimethylsiloxane (PDMS) membranes with tunable elastic properties were fabricated by adjusting the ratio of the curing agent (B agent), with the 1/50 ratio exhibiting the greatest extensibility and the lowest Young’s modulus. Experimental results demonstrate that wing membrane elasticity significantly influences aerodynamic performance. During flapping, increased elasticity led to larger camber changes, enhancing vertical lift through stronger leading-edge vortices, as confirmed by PIV flow field measurements. However, when elasticity became excessively high, as in the 1/50 membrane, the lift benefit diminished, and horizontal force decreased, indicating a trade-off between vertical and horizontal aerodynamic performance. Additionally, the folding mechanism was found to be critical for drag reduction, reducing nearly 50% of negative horizontal forces during flight. By integrating adjustable wing membrane properties and a bioinspired flapping mechanism, this research provides valuable insights into the aerodynamic characteristics of bat flight. These findings not only enhance the understanding of flapping wing aerodynamics but also offer guidance for the design of efficient and agile bioinspired aerial vehicles. Full article

In view of the fact that the specification does not specify the calculation model for the temperature gradient of the concrete box-shaped arch rib without wing plates, and there is also a lack of relevant research on the temperature model of this type of arch rib, this paper carries out research on the impact of sunshine temperature on a section of concrete box arch rib without a flange plate based on the 355 m Shuiluohe Bridge. Firstly, a temperature experiment of the arch rib without flange plates was conducted. According to the experimental data, the temperature distribution and changing rules of the arch rib cross-section were analyzed. Then, according to the measured temperature data, a calculation mode of the vertical temperature gradient of the arch rib was proposed and compared with the specification. Finally, in view of the most disadvantageous phases of the arch rib in the construction process, the influence of different gradient modes on the structural mechanical behavior was analyzed by means of a simulation model. The results show that along the span from the springing to L/2, the maximal temperatures of the top plate, web plate and bottom plate gradually increase. The temperature gradient of the box’s top plate is the largest, that of the web plate is the second largest, and that of the bottom plate is the smallest. The vertical temperature difference of the key section of the arch rib gradually increases from the springing to L/2, and the maximal temperature difference of the section at L/2 is 16.3 °C, which is 4.2 °C higher than that of the springing section. The vertical temperature gradient proposed in this paper is a four-fold nonlinear model. Compared with the temperature gradient distribution range specified in the specification, the vertical temperature gradient in this article has a wider distribution range in the cross-section height, and the temperature varies more quickly along the cross-section height. The temperature gradient model proposed has more adverse effects on the mechanical behavior of the structure. The temperature gradient model proposed in this paper not only fills the gap in the specification but also provides suggestions for the design and construction of bridges. Meanwhile, the temperature distribution model of this type of arch rib also lays a theoretical foundation for the further development of corresponding thermal insulation materials for concrete surfaces or new concrete materials. Full article

Flying cars are envisioned as key components of the Future Comprehensive Transport Network System. Current flying car designs struggle to balance ground maneuverability with aerial agility, which means they cannot operate on standard roads (3.5 m width). Additionally, the low energy density of existing aviation batteries limits their operational range. Therefore, a high lift-to-drag ratio (L/D) improves efficiency by reducing drag and extending the operational range. This leads to more economical and efficient flight performance, making it particularly beneficial for flying cars. This paper addresses the challenges of the land–air amphibious design and high-L/D configuration design of flying cars, and Computational Fluid Dynamics (CFD) simulations were conducted to optimize the overall configuration of a flying car, followed by creating a 1:4-scale model and validating its aerial posture. The results confirmed the structural integrity of the tilting and folding wing design for amphibious flying cars, achieving a fixed-wing mode L/D of 11. This design effectively addresses the traditional flying car issue of neglecting ground travel requirements by focusing solely on the flight capabilities of simulated aircraft or drones. Full article

Birds are capable of bidirectional changes in wing morphology, transitioning from folded to extended states or vice versa during takeoff and landing. However, most bird-like robots struggle with wing folding, resulting in poor biomimicry and an inability to meet the attitude requirements for flapping wings in multimodal movements. This paper presents a multi-motor solution with an attitude transformation mechanism based on a crank-rocker structure, enabling the wings to transition between folded and extended states while performing flapping, twisting, sweeping, bending, and their coupled motions. A kinematic model of the mechanism is developed, and the length constraints of the main linkages during key movements are derived. A prototype is designed and tested to evaluate the primary flight attitudes required for both basic and multimodal movements. The test results demonstrate that the attitude transformation mechanism, through coordinated motor operation, can replicate the wing movements of birds during different flight phases, allowing the robotic bird’s flapping wings to achieve bird-like flexibility in motion. The key angles of the wing motion were measured using a motion capture system, confirming the accuracy of the kinematic model. Full article

The method proposed in this paper provides a new research idea for biomimetic three-dimensional grid structure material design. The wings of a dragonfly exhibit a complex grid structure, comprising approximately 1–2% of its total weight, yet demonstrating exceptional mechanical efficiency. In order to investigate the feasibility of applying the design optimization method simulating this structure to the material structure design, we adopted a multi-step method to realize the formation of multi-scale grid structures and folds. Initially, the main vein of the front wing was simulated using a branching structure generation technique. Subsequently, a Voronoi grid was overlaid to generate the complete bionic grid structure. Finally, the fold structure of the wing was simulated using origami principles to create a three-dimensional grid structure. This method can obtain the rigid–flexible coupling 3D grid structure by simulating the 3D fold structure design of the dragonfly wing. The results show that the proposed method can obtain structural materials with excellent structural properties by simulating the structural characteristics of dragonfly wings. Full article

Orchids have evolved flowers with unique morphologies through coevolution with pollinators, such as insects. Among the floral organs, the lip (labellum), one of the three petals, exhibits a distinctive shape and plays a crucial role in attracting pollinators and facilitating pollination in many orchids. The lip of the terrestrial orchid Habenaria radiata is shaped like a flying white bird and is believed to attract and provide a platform for nectar-feeding pollinators, such as hawk moths. To elucidate the mechanism of lip morphogenesis, we conducted time-lapse imaging of blooming flowers to observe the extension process of the lip and analyzed the cellular morphology during the generation of serrations. We found that the wing part of the lip folds inward in the bud and fully expands in two hours after blooming. The serrations of the lip were initially formed through cell division and later deepened through polar cell elongation. Transcriptome analysis of floral buds revealed the expression of genes involved in floral organ development, cell division, and meiosis. Additionally, genes involved in serration formation are also expressed in floral buds. This study provides insights into the mechanism underlying the formation of the unique lip morphology in Habenaria radiata. Full article

This study investigates the unsteady aerodynamic mechanisms underlying the efficient flight of birds and proposes a biomimetic flapping-wing aircraft design utilizing a double-crank double-rocker mechanism. Building upon a detailed analysis of avian flight dynamics, a two-stage foldable flapping mechanism was developed, integrating an optimized double-crank double-rocker structure with a secondary linkage system. This design enables synchronized wing flapping and spanwise folding, significantly enhancing aerodynamic efficiency and dynamic performance. The system’s planar symmetric layout and high-ratio reduction gear configuration ensure movement synchronicity and stability while reducing mechanical wear and energy consumption. Through precise modeling, the motion trajectories of the inner and outer wing segments were derived, providing a robust mathematical foundation for motion control and optimization. Computational simulations based on trajectory equations successfully demonstrated the characteristic figure-eight wingtip motion. Using 3D simulations and CFD analysis, key parameters—including initial angle of attack, aspect ratio, flapping frequency, and flapping speed—were optimized. The results indicate that optimal aerodynamic performance is achieved at an initial angle of attack of 9°, an aspect ratio of 5.1, and a flapping frequency and speed of 4–5 Hz and 4–5 m/s, respectively. These findings underscore the potential of biomimetic flapping-wing aircraft in applications such as UAVs and military technology, providing a solid theoretical foundation for future advancements in this field. Full article

In recent years, bioinspired insect flight has become a prominent research area, with a particular focus on beetle-inspired aerial vehicles. Studying the unique flight mechanisms and structural characteristics of beetles has significant implications for the optimization of biomimetic flying devices. Among beetles, Allomyrina dichotoma (rhinoceros beetle) exhibits a distinct wing deployment–flight–retraction sequence, whereby the interaction between the hindwings and protective elytra contributes to lift generation and maintenance. This study investigates A. dichotoma’s wing deployment, flight, and retraction behaviors through motion analysis, uncovering the critical role of the elytra in wing folding. We capture the kinematic parameters throughout the entire flight process and develop an accurate kinematic model of A. dichotoma flight. Using smoke visualization, we analyze the flow field generated during flight, revealing the formation of enhanced leading-edge vortices and attached vortices during both upstroke and downstroke phases. These findings uncover the high-lift mechanism underlying A. dichotoma’s flight dynamics, offering valuable insights for optimizing beetle-inspired micro aerial vehicles. Full article

The folding wing deployment mechanisms of aircraft are constrained by weight and space limitations, necessitating fewer actuators, multiple outputs, compact designs, and high efficiency. However, existing folding wing mechanisms often overlook the impact of performance in configuration design. Additionally, they struggle to achieve the synchronous unfolding of multiple wings using a single drive. This paper presents a design methodology for multi-wing deployment mechanisms based on configuration topology and multiple performance indicators. Specifically, seventeen configurations of multi-wing deployment mechanisms are developed based on functional requirements, along with expression methods for performance indicators, including compactness, mechanism stiffness, dynamic sensitivity, motion transmission, and joint transmission efficiency. The optimal configuration for the multi-wing deployment mechanism is identified utilizing the fuzzy comprehensive evaluation. Moreover, the transmission efficiency of multiple configurations is calculated across different scale parameters. Simulation analyses and prototype experiments are conducted to validate the design. The results indicate that the transmission efficiency of the optimized configuration consistently exceeds that of the other configurations. Maximum efficiencies surpass those of the other configurations by 2.4% and 5.7%. Importantly, this study introduces a quantitative expression method for multiple performance indicators at the configuration design stage. This approach enables the integration of various performance metrics with configuration designs. Overall, this research provides a novel approach for the innovative design of multi-wing deployment mechanisms in aircraft. Additionally, considering performance in the selection of mechanism configurations during engineering design offers valuable insights and potential applications. Full article

The foldable tail wing system of UAVs offers advantages such as reducing the envelope size and improving storage space utilization. However, due to the compact tail wing space, achieving multi-modal locking and unlocking functionality presents significant challenges. This paper designs a new smart SMA actuator for the use of UAV foldable tail wings. The prototype testing demonstrated the advantages and engineering practicality of the actuator. The core content includes three main parts: thermomechanical testing of the SMA actuation performance, structural design of the actuator, and the fabrication and actuation testing of the prototype. The key parameters related to actuation performance, such as phase transformation temperature and actuation force, were determined through DSC and tensile testing. The geometric parameters of the tail wing were determined through kinetics and kinematic analyses. Through the linkage design of two kinematic pairs, the SMA actuator enables both the deployment and locking of the tail wing. The prototype testing results of the folding tail wing show that, after vibration and temperature variation tests, the SMA actuator is still able to output an actuation stroke of 2.15 mm within 20 ms. The SMA actuator integrates locking for both modes of the tail wing and unlocking during mode transitions, offering advantages such as fast response and minimal space requirements. It provides an effective solution tailored to the needs of the foldable tail wing system. Full article

Birds use their claws to perch on branches, which helps them to recover energy and observe their surroundings; however, most biomimetic flapping-wing aircraft can only fly, not perch. This study was conducted on the basis of bionic principles to replicate birds’ claw and wing movements in order to design a highly biomimetic flapping-wing aircraft capable of perching. First, a posture conversion module with a multi-motor hemispherical gear structure allows the aircraft to flap, twist, swing, and transition between its folded and unfolded states. The perching module, based on helical motion, converts the motor’s rotational movement into axial movement to extend and retract the claws, enabling the aircraft to perch. The head and tail motion module has a dual motor that enables the aircraft’s head and tail to move as flexibly as a bird’s. Kinematic models of the main functional modules are established and verified for accuracy. Functional experiments on the prototype show that it can perform all perching actions, demonstrating multi-modal motion capabilities and providing a foundation upon which to develop dynamics models and control methods for highly biomimetic flapping-wing aircraft with perching functionality. Full article