An Origami-Like Sheath of a Honeybee Tongue for Fluid Viscosity Sensing

Mechanoreceptors play a vital role for animals to sense and monitor environmental parameters,like flow speed,tactile resistance,and pressure.The hairy-structured trichoid sensillum,a common type of mechanoreceptor in insects,is generally non-motile,embedded in a socket connected with cuticular substrate.However,we discover that the trichoid sensilla on the tongue of western bees(Apis mellifera L.)is rotatable and can be actively maneuvered by bees.The trichoid sensilla together with the socket base are mounted on the origami-like sheath of the tongue,and can rotate outwards along with the deformation of the tongue sheath.We illustrate that the rotation of the tongue sensilla hairs can locally generate shear force in the liquid to sense the viscosity,which may facilitate bees to adjust their feeding strategies.The viscosity sensitivity of the rotatable trichoid sensilla based on the origami-like mechanism,according to our mechanical model,is 13 times greater than that of the fixed sensilla.In addition,our finite element analysis shows that strain would concentrate on the trichoid sensilla base when rotating in the liquid,which may structurally enhance its perception sensitivity.This study reports a new mechanism of active mechanoreceptors and may have implications for origami mechanisms with correlative functional components,especially for micro-robotic systems used in underwater viscosity sensing.

Mechanistic Analysis and Bio-inspired Applications for a Bidirectional Stiffness of a Water Snail Operculum

The water snail Pomacea canaliculata retracts the discoidal and multi-layered operculum to protect the soft body from being attacked by predators,and releases it when threats lifted.However,the duration of the operculum retraction is usually less than that of the operculum protraction.In this paper,we elucidate the biological compliant mechanism of the operculum.By using confocal laser scanning microscopy,we find that the operculum has compliant sandwiched layers between hard layers.The layered structure results in a compliant mechanism with a bidirectional stiffness for the locking and unlocking processes of the operculum.A mathematical model is derived to rationalize the bidirectional stiffness mechanism of the operculum.In addition,we carry out the experiments on the locking and unlocking processes.The experimental results show that the locking tension is about two-fifths of the unlocking tension of the operculum.Moreover,based on the mechanical properties of the operculum with the layered structure,we designed an operculum-inspired structure,which may have a variety of potential applications in combined driving patterns.

The increasing expression of GPX7 related to the malignant clinical features leading to poor prognosis of glioma patients

Background:Glioma is the most common malignant brain tumor in adults.The standard treatment scheme of glioma is surgical resection combined alternative radio-and chemotherapy.However,the outcome of glioma patients was unsatisfied.Here,we aimed to explore the molecular and biological function characteristics of GPX7 in glioma.Methods:The multidimensional data of glioma samples were downloaded from Chinese Glioma Genome Atlas(CGGA).RT-qPCR method was used to identify the expression status of GPX7.Kaplan–Meier curves and Cox regression analysis were used to explore the prognostic value of GPX7.Gene Set Enrichment Analysis(GSEA)was applied to investigate the GPX7-related functions in glioma.Results:The results indicated that the expression of GPX7 in glioma was higher compared to that in normal brain tissue.Univariate and multivariate Cox regression analyses confirmed that the expression value of GPX7 was an independent prognostic factor in glioma.The GSEA analysis showed that GPX7 was significantly enriched in the cell cycle pathway,ECM pathway,focal adhesion pathway,and toll-like receptor pathway.Conclusions:The GPX7 was recommended as an independent risk factor for patients diagnosed with glioma for the first time and GPX7 could be potentially used as the therapy target in future.Furthermore,we attempted to explore a potential biomarker for improving the diagnosis and prognosis of patients with glioma.

A Mathematical Modeling Method Elucidating the Integrated Gripping Performance of Ant Mandibles and Bio-inspired Grippers

The ability to grip unhatched eggs is a skill exploited by the ants Harpegnathos venator,as they care their brood in tunneled nests,which is of extreme difficulty to keep the eggs intact while gripping.In this paper we propose a mathematical modeling method to elucidate the mechanism of such a gripping behavior in the ant mandibles.The new method can be subdivided into following steps.As a preliminary,the concavity geometry and mandible kinematics are examined experimentally.Second,coordinate transformation is used to predict the real-time spatial topology of the concavity.Third,we come up with a new method to quantify the workspace required to grip and the contact area between the concavity and ant egg.Our model indicates that the biaxial rotation fashion with specialized concavities can reduce workspace by 40%and increase contact area by 53%on average compared with the uniaxial rotation pattern,which augments success rate of gentle gripping.This methodology may have applications in evaluating mechanical performance in both natural and artificial grippers.

Effects of Nectar Property on Compensated Dipping Behavior of Honey Bees with Damaged Tongues

In nature,bees with damaged tongues are adapted to have a feat in collecting nectariferous sources in a large spectrum of concentrations(19%-69%)or viscosities(10^(-3)Pa·s to 10^(-1)Pa·s);however,eff ects of nectar property on compensated dipping behavior remain elusive.Combining the bee tongue anatomy,high-speed videography,and mathematical models,we investigate responses of honey bees with damaged tongues to fluidic sources in various properties.We find that,bees with 80%damaged tongues are deprived of feeding capability and remarkably,the dipping frequency increases from 4.24 Hz to 5.08 Hz while ingesting 25%sugar water when the tongue loses 0-30%in length,while declines from 5.08 to 3.86 Hz in case of 30%damaged tongue when sucrose concentration increases from 25%to 45%.We employ the energetic compensation rate and energetic utilization rate to evaluate eff ectiveness of the compensation from the perspective of energetic regulation.The mathematical model indicates that the energetic compensation rate turns higher in bees with less damaged tongues for ingesting dilute sugar water,demonstrating its capability of functional compensation for combined factors.Also,the tongue-damaged bees achieve the highest energetic utilization rate when ingesting~30%sugar water.Beyond biology,the findings may shed lights on biomimetic materials and technologies that aim to compensate for geometrical degradations without regeneration.