Natural Creatures Research Articles

Biomimetic Self-Adhesive Structures for Wearable Sensors.

Inspired by the adhesion ability of various organisms in nature, the research of biomimetic adhesion has shown a promising application prospect in fields such as manipulators, climbing robots and wearable medical devices. In order to achieve effective adhesion between human skin and a variety of wearable sensors, two natural creatures, octopus and mussel, were selected for bio-imitation in this paper. Through imitating the octopus sucker structure, a micro-cavity array with a large inner cavity and small outer cavity was designed. The fabrication was completed by double-layer adhesive photolithography and PDMS molding, and the adhesion capacity of the structure was further enhanced by the coating of thermal responsive hydrogel PNIPAM. The adhesive force of 3.91 N/cm2 was obtained in the range of the human body temperature. PDA-Lap-PAM hydrogel was prepared by combining mussel foot protein (Mfps) with nano-clay (Lap) as biomimetic mussel mucus. It was found that 0.02 g PDA-Lap-PAM hydrogel can obtain about 2.216 N adhesion, with good hydrophilicity. Through oxygen plasma surface treatment and functional silane surface modification, the fusion of the PDMS film with biomimetic octopus sucker structure and the biomimetic mussel mucus hydrogel patch was realized. The biomimetic octopus sucker structure was attached to the human skin surface to solve the problem of shape-preserving attachment, and the biomimetic mussel mucus hydrogel was attached to the sensor surface to solve the problem of sensor surface adaptation. The fusion structure was used to attach a rigid substrate piezoelectric sensor to the skin for a human pulsewave test. The results verified the self-adhesion feasibility of wearable sensors with biomimetic structures.

Bioinspired Robust Mechanical Properties for Advanced Materials

Nature is a substantial repository for various kinds of aquatic, terrestrial, and wind‐borne plants and animals adapting extensively to sustain life on earth's different environmental conditions. The organisms or structures of these natural creatures possess extraordinary properties or functionalities through well‐organizing usually weak biopolymers and bioinorganic structures, which provide good examples to emulate their mechanical and structural characteristics in materials innovations and discoveries. This review collectively investigates the studies of the structures and mechanical properties of some representative fauna and flora with robust mechanical properties and the corresponding bioinspired materials with mimicking structures and mechanical properties. By learning from the natural structures with robust mechanical properties, bioinspired materials and composites with superior mechanical performance to the constituent materials have been designed and fabricated. Via this study, there is hope to draw some principles for designing innovative materials with extraordinary properties from existing common materials by learning from nature. It is expected that the understanding of the extraordinary natural mechanical properties and the robust bioinspired materials can provide some insights into the design of novel materials and composites.

Bird Cottage

Bird Cottage

Bio‐Inspired Self‐Hydrophobized Sericin Adhesive with Tough Underwater Adhesion Enables Wound Healing and Fluid Leakage Sealing

AbstractGiven that adhesion‐resistance of water severely weakens the bonding strength of tissue adhesives, instant adhesion to wet biological tissue surfaces remains challenging. Inspired by the robust underwater adhesion of natural creatures (such as mussels and barnacles whose underwater adhesion derives from the synergy of hydrophobic and adhesive matrix), a self‐hydrophobized adhesive is developed by co‐assembly of disulfide‐bond hydrolyzed hydrophobic natural sericin protein (a major component of silkworm silk fibers) and tannic acid. Once exposed to water, the self‐aggregation of hydrophobic chains within the adhesive repels water and enhances interfacial hydrogen bonding or electrostatic interactions, mechanistically leading to a robust (>0.5 MPa for solid plates and >0.1 MPa for tissues) and durable (still maintained at 0.4 Mpa even after five cycles) underwater adhesion. Owing to its robust underwater adhesion property, this adhesive possesses multiple advantages outperforming commercial adhesives, such as in vivo wound healing‐promoting effects, effective fluid leakage sealing, and rapid hemostasis activity. This study not only offers a novel strategy for designing and fabricating an underwater adhesive with natural protein but also provides a new adhesive for various potential applications, including promoting wound healing and hemostasis.

Bioinspired Environment Exploration Algorithm in Swarm Based on Lévy Flight and Improved Artificial Potential Field

Inspired by the behaviour of animal populations in nature, we propose a novel exploration algorithm based on Lévy flight (LF) and artificial potential field (APF). The agent is extended to the swarm level using the APF method through the LF search environment. Virtual leaders generate moving steps to explore the environment through the LF mechanism. To achieve collision-free movement in an unknown constrained environment, a swarm-following mechanism is established, which requires the agents to follow the virtual leader to carry out the LF. The proposed method, combining the advantages of LF and APF which achieve the effect of flocking in an exploration environment, does not rely on complex sensors for environment labelling, memorising, or huge computing power. Agents simply perform elegant and efficient search behaviours as natural creatures adapt to the environment and change formations. The method is especially suitable for the camouflaged flocking exploration environment of bionic robots such as flapping drones. Simulation experiments and real-world experiments on E-puck2 robots were conducted to evaluate the effectiveness of the proposed LF-APF algorithm.

Magnetic Actuator with Programmable Force Distribution and Self‐Sensing for Bidirectional Deformation Control

AbstractThe realization of bidirectional deformation function is an important symbol of most natural creatures and intelligent flexible robots. Currently, most soft actuators are developed on the basis of transition between two different states, which means difficulties of control during the whole movement. In this work, variable distribution positions of hard magnetorheological elastomers (H‐MREs) in the matrix are used to achieve different magnetic force distributions. The programmable force distribution promotes different deformations of the magnetic actuators, which enlarges the deformation range by 51.69% under the same magnetic field. Pre‐magnetizing the H‐MREs makes them have a certain residual magnetization. Due to the residual magnetization property of H‐MREs, the magnetized actuator can not only be attracted but also be repelled by the applied magnetic field. This bidirectional deformation capability gives the actuators a wider deformation range and greater clamping force, such as the smart gripper for pinching up object. In addition, the actuators are integrated with a flexible sensing layer with high resolution and strong stability for self‐sensing. This kind of force distribution programmable technology and self‐sensing performance have the potential to broaden the application of actuators in medical equipment requiring high control accuracy.

Investigation and mapping of natural and artificial radioactivity in sediment samples from Borçka Black Lake, Artvin-Turkey

ABSTRACT All living creatures in nature are constantly exposed to ionising radiation, which is emitted from natural and artificial radiation sources. For this reason, it is important to monitor the levels of radioactivity in living spaces and visited areas. In this study, natural (238U, 232Th, 40K) and artificial (137Cs) radioactivity concentrations in sediment samples taken from Borçka Black Lake located on the Nature Park in Artvin province were determined using a high purity germanium detector (HPGe). It was determined that 238U, 232Th, 40K and 137Cs radioisotope concentrations in the sediment samples varied between 8.73 and 26.45, 7.01 and 22.98, 289.92 and 578.98, and 6.26 and 70.96 Bq kg−1, respectively. Mean radioactivity concentrations were found to be 14.99 ± 0.89 Bq kg−1 for 238U, 13.85 ± 1.10 Bq kg−1 for 232Th, 473.67 ± 14.21 Bq kg−1 for 40K and 35.06 ± 0.96 Bq kg−1 for 137Cs. In order to evaluate the radiological hazards, radium equivalent activity, external hazard index, absorbed dose rate in the air, the annual effective dose rate and excess life time cancer risk were calculated and compared with the values recommended by international organisations. As a result, it has been shown with this study that the radioactivity caused by the examined radioisotopes will not pose any health risk for the visitors of Borçka Black Lake.

Ultrasensitive, Highly Stable, and Flexible Strain Sensor Inspired by Nature.

For advanced flexible strain sensors, it is not difficult to achieve high sensitivity only. However, integrating high sensitivity, high stability, and high durability into one sensor still remains a great challenge. Fortunately, natural creatures with diversified excellent performances have given us a lot of ready-made solutions. Here, scorpion and spiderweb are selected as coupling bionic prototypes, which are famous for their ultrasensitive sensing capacity and excellent structural durability, respectively. Based on that, a bioinspired strain sensor is successfully fabricated. The results demonstrate that the bioinspired strain sensor has a sensitivity of 940.5 in the strain range of 0-1.5% and a sensitivity of 2742.3 between 1.5 and 2.5%. Meantime, this sensor with a spiderweb-like reticular structure has a great improvement in stability and durability. Specifically, the sensor exhibits excellent stability during bending and stretching cycles over 80,000 times. Moreover, the response time and recovery time of the sensor are 169 and 195 ms, respectively. Besides, the sensor also has functions such as vibrating frequency identification due to its low hysteresis. Based on the excellent performance, the sensor can be applied to monitor human body motions serving as wearable electronics.

A mini-review: positive impact of COVID-19 on Arial health and ecology.

COVID-19 can cause global pandemics; however, no specific vaccine has been recommended for COVID-19. Nearly 216 countries are trying to stop the spread of the disease, recover from it, and improve its mobility. In a way that people have not experienced in recent years, the COVID-19 pandemic affected humans through the year 2020. To stop the spread of the disease, many governments declared a complete lockdown.The nationwide lockdown had some positive effects on the environment even though it led to a decline in global economic growth. Air pollution levels reduced dramatically as a result of this lockdown on pollution. Most of Europe’s populated cities saw a reduction in NO2 concentration of 45–54%. COVID-19 and air, water, and ecology are connected via two pathways, one occurring before the spread of the disease and the other following after. As a result of industrial activity, transportation, and high human density, pollutants were high in many areas before the disease spread. There was a reduction in population movements as well as a decline in human activities which resulted in a reduction in carbon dioxide emissions, an improvement of the ozone layer, as well as improvements in the Earth’s weather and environment. As a result of a COVID-19 pandemic, human activities are negatively impacted, and the environment is positively affected. Our objective is to provide an assessment of the impact of human activities on the environment and ecology. During times of lockdown, there is a correlation between atmospheric changes and the behavior of natural creatures. Several significant findings are presented, including air pollution reduction, air quality improvement, ozone healing, and ecological sustainability. COVID-19 is beneficial for aerial health, aquatic health, and ecology in this paper.

A Novel Biomimetic Wing Design and Optimizing Aerodynamic Performance

In this article, numerical and experimental analyzes were made by adding winglet and endless blade to the tip of the airfoil to improve the wind turbine blade performance. Similarly, the change in performance was investigated by making notches at different sizes and distances on the trailing edge of the wing structure, inspired by the creatures in nature. First of all, the designed wing structures were analyzed by numerical analysis as a fixed wing, and the lift and drag forces were examined and the aerodynamic performance parameters were examined. Then, the winglet, endless wing and trailing edge notch were mounted to the wing structure cast from a 3D printer, and the energy parameters produced by each design in the wind tunnel were examined. In curved wings, the stress values produced depending on the size of the endless wing structure added to the wing tip have changed and up to 15% aerodynamic performance improvement has been observed in the designed wing structure. In addition, the design was experimentally examined on conventional fixed blades, and up to 6% improvement was observed on fixed blades.

3D-printable colloidal photonic crystals

The architecture of the colloidal photonic crystals (CPCs) is of paramount importance to their functionality and applications. Nevertheless, the realization of CPCs with arbitrarily designed, volumetrically sophisticated structures at the macroscale remains challenging. In this work, a printable CPC ink was developed. By combining this ink with a digital light processing (DLP)-based three-dimensional (3D) printing system, we were able to fabricate the CPC superstructures featuring both digitally defined macroscale geometries and structural colors originating from the ordered structures at the sub-micron scale. Moreover, besides the arbitrarily adjustable and precisely designable architectures, the optical properties, mechanical performances, and stimuli-responsiveness of the printed objects could also be facilely tuned by the composition of the ink or the printing parameters of the DLP system. This technology endows us the ability to fabricate CPCs with a multitude of desirable functions as well as mimic the hierarchical structures and color-manipulation strategies of some creatures in nature, which paves the way for potentially broad applications in intelligent color displays, 3D integrated sensors, biomimetic color-morphing soft robots, and smart anti-counterfeiting labels, among others.

Migration based on environment comparison promotes cooperation in evolutionary games

Human beings and natural creatures often migrate in search of better environments. When both local and global environments can be perceived by individuals, they may determine whether to migrate or not based on the comparison. If the individuals realize the local environments are worse than the global ones, they are more likely to leave their original place. Otherwise, they may choose to stay still. Considering these, we study the evolutionary games in a dynamically changing population on a square lattice, in which the players migrate based on the comparison between local and global environments. The simulation results show that cooperation can be significantly promoted. By examining the strategy patterns during the evolution, we find there exist two evolutionary stages that account for the enhancement of cooperation. One is the clustering of cooperators, in which cooperator clusters get strengthened by slow migration of cooperators and fast migration of defectors. The other is the coalescence of cooperator clusters, which induces further increment of the cooperation level. Besides, we investigate the effects of two different types of noises on cooperation, which are introduced in migration and in strategy imitation, respectively. The results reveal that cooperation could be enhanced by low migration noise whereas high strategy-adoption noise.

A STUDY ON THE MUD PUDDLING ACTIVITY OF BUTTERFLIES IN ALAGARKOVIL HILLS, MADURAI, TAMIL NADU, INDIA

Butterflies are one of the most remarkable creatures of nature, which exhibits an interesting behavior called puddling. The term puddling is used to describe the supplementary feeding of minerals and salts from mud puddles, excrement and carrion. The mud puddling activity of lepidopterans have great significance in influencing the nutritional and reproductive status of the insects. This study aims to record the mud puddling activity of butterflies in Alagarkovil hills, a reserve forest area with rich biodiversity and high anthropogenic activity; and test the soil sample for various minerals and salts to understand the importance of mud puddling in the reproductive behavior of butterflies. The survey of butterflies was done on six sites in the Alagarkovil hills, from July 2017- January 2018 on sunny days, between 0800-1600 hrs, thrice a week using the transect method. A total of 111 species belonging to six families were recorded during the study period, of which the Lycaenidae, Nymphalidae and Pieridae families were mostly found to exhibit mud puddling. In agreement with previous findings, greater numbers of male butterflies were found to participate in mud puddling. Among the six study sites, the mud puddling activity was predominant in the site with copious puddles. The soil analysis of the mud puddling sites showed the presence of salts like sodium and potassium, metal ions like manganese, iron and copper, macro elements like phosphorus, nitrogen and carbon. The percentage of sodium and potassium were found to be higher, which were reported to be the chief elements consumed during mud puddling. The alkaline pH of the soil was found to favor the puddling activity. All these abiotic factors play a significant role in the nutritional and reproductive biology of the butterflies, which can be monitored to assess the community status and diversity of butterflies in an area. Conservation of mud puddling sites could help restore the biodiversity index of the butterflies.

Underwater Soft Robotics: A Review of Bioinspiration in Design, Actuation, Modeling, and Control.

Nature and biological creatures are some of the main sources of inspiration for humans. Engineers have aspired to emulate these natural systems. As rigid systems become increasingly limited in their capabilities to perform complex tasks and adapt to their environment like living creatures, the need for soft systems has become more prominent due to the similar complex, compliant, and flexible characteristics they share with intelligent natural systems. This review provides an overview of the recent developments in the soft robotics field, with a focus on the underwater application frontier.

Laser Fabrication of Titanium Alloy-Based Photothermal Responsive Slippery Surface

In recent years, biomimetic materials inspired from natural organisms have attracted great attention due to their promising functionalities and cutting-edge applications, emerging as an important research topic. For example, how to reduce the reflectivity of the solid surface and increase the absorption of the substrate surface is essential for developing light response smart surface. Suitable solutions to this issue can be found in natural creatures; however, it is technologically challenging. In this work, inspired from butterfly wings, we proposed a laser processing technology to prepare micro nanostructured titanium alloy surfaces with anti-reflection properties. The reflectivity is significantly suppressed, and thus, the light absorption is improved. Consequently, the anti-reflection titanium alloy surface can be further employed as a photothermal substrate for developing light-responsive slippery surface. The sliding behavior of liquid droplets on the smart slippery surface can be well controlled via light irradiation. This method facilitates the preparation of low-reflection and high-absorption metallic surfaces towards bionic applications.

Dynamic study of a stochastic Holling III predator-prey system with a prey refuge

Based on the truth that creatures in nature are concerned about environmental noise, we establish a stochastic Holling III predator-prey system with a prey refuge. In this stochastic system, the well-posedness of the system is investigated. For the extinction and persistence in mean, the threshold conditions are given in the next. Furthermore, the stochastic persistence of the system is also proved. At last, the main results are verified through numerical simulations. Biologically, it is observed that white noise can suppress the survival of populations.

The Sacredness of Nature: Response to Six Objections to Religious Naturalism

The Sacredness of Nature: Response to Six Objections to Religious Naturalism

Major threats and habitat use status of Demoiselle crane (Anthropoides virgo), in district Bannu, Pakistan.

Cranes are the large and attractive Creatures of nature with long necks, legs, and life-span. Adults of both sexes are the same with similar color patterns. Demoiselle cranes spend most of their lifespan on dry grasses. They are also found around the stream, rivers, shallow lakes, natural wetlands, and depressions. To evaluate the current status of habitat use and major threats a study was conducted in tehsil Domel district Bannu. Line transect method and water quality tests (temperature, PH, contamination of E-coli bacteria) were used. To determine the major threats questionnaire method was used. The whole data was analyzed by using SPSS 21 version. Based on the distribution four study sites were selected and four water samples from each study site were taken. Most sites were moderate to highly degraded except Kashoo and kurram river mixing point which was low degraded with livestock grazing and human activities. Water quality tests showed PH ranges from 7-9, temperature 6.5-8.5, and contamination of E-coli in all samples. The social survey revealed that hunting, habitat degradation, and pollution as major threats. Effective long-term conservation and management in the study area are needed to focus on the protection of disturbance-free habitat.

Income Gap Equalization Based on PSO Algorithm in Edge Computing Environment.

In order to explore the current income gap, a method based on the PSO algorithm in the edge computing environment is proposed. PSO calculates and simulates bird flock foraging activities, the Frank Heppner biological group model, and the three rules in bird activities. After studying the activities of these natural creatures, abstract problems are quantified and similar models established. The Gini coefficient is calculated by using grouped data, and the grouping basis is also innovative. The quantile grouping method is adopted, which can effectively solve the difference between the concentration index and the Gini coefficient, and the Gini coefficients of each year can be added up to finally get the Gini coefficient of the stock income. Experimental results show that the Gini coefficient of traffic income in 2017 and 2018 had dropped significantly, but the variation of the Gini coefficient of stock income (Delta CG) was still greater than 0. Obviously, the adjustment speed of the Gini coefficient of stock income was lagging behind, as was the Gini coefficient of traffic income. We found that after 1986, the facilitation effect was greater than the dilution effect, and the facilitation effect continued to push up the stock income gap, which indicated more income flow to the high-income group, with the income flow gap showing an upward trend and the upward trend becoming more and more obvious. It has been proved that the PSO algorithm can effectively identify the income gap in the edge computing environment, and the corresponding policy suggestions are given.

Fabrication of Dual Self-Healing Multifunctional Coating Based on Multicompartment Microcapsules.

By designing and preparing multifunctional materials exhibiting self-healing ability, problems related to their durability outdoors can be solved. This study, inspired by the self-healing mechanism of natural creatures, successfully prepared a dual self-healing multifunctional coating using temperature stimuli-responsive multicompartment microcapsules. Phase change materials (PCMs) were employed to load multicompartment microcapsules that were produced through Pickering emulsion polymerization by applying hydrophobic materials encapsulated by titanium dioxide (TiO2) nanocapsules as Pickering emulsifiers. The multifunctional coating produced using microcapsules and self-healing waterborne polyurethane (WPU) exhibited thermal insulation and antireflection properties, which was attributed to the application of PCMs and TiO2, and it also achieved remarkable superhydrophobicity. Moreover, this coating exhibited the intrinsic and superficial dual self-healing ability, which was attributed to the release of hydrophobic materials from microcapsules and the self-healing ability of WPU. This study can be referenced to guide the fabrication of high-performance self-healing materials, and it can contribute to the long-term use of multifunctional coatings.