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A human vestibular system is a group of devices in the inner ear that govern the balancing movement of the head, in which the saccule is responsible for sensing gravity accelerations. Imitating the sensing principle and structure of the Sensory Hair (SH) cell in the saccule, a Bionic Sensory Hair (BSH) was developed, and 9 BSH arrays were arranged in the bionic macular at the bottom of the spherical shell to prepare a Bionic Saccule (BS). Based on the piezoelectric equation, the electromechanical theoretical models of the BSH cantilever and BS were deduced. They were subjected to impact oscillations using an exciter, and their output charges were analyzed to check their sensing ability. The results showed that BSH could sense its bending deflection, and the BS could sense its position change in the sagittal plane and in space. They exhibited a sensitivity of 1.6104 Pc s2/m and a fast response and similar sensing principles and low resonance frequency to those of the human saccule. The BS is expected to be used in the field of robotics and clinical disease diagnosis as a part of the artificial vestibular system in the future. [ABSTRACT FROM AUTHOR]

Objective To use the high-performance liquid chromatography (HPLC) method and desorption electrospray ionization-mass spectrometry imaging (DESI-MSI) method to study the dynamic accumulation and distribution of secondary metabolites of Coptis chinensis in different growth years. Methods Using the samples of one-, three-, and five-year Coptis chinensis as the research object, the HPLC method was used to determine the contents of seven index components (jatrorrhizine hydrochloride, columbamine, epiberberine, coptisine hydrochloride, palmatine hydrochloride, berberine hydrochloride, and magnoflorine) as the secondary metabolites of Coptis chinensis. Further, the distribution of seven index components in the one-, three- and five-year Coptis chinensis slices were qualitatively analyzed by using the DESI-MSI method. Results The HPLC result showed that the contents of berberine hydrochloride and palmatine hydrochloride, jatrorrhizine hydrochloride, columbamine, and magnoflorine in five-year Coptis chinensis were the highest; coptisine hydrochloride and epiberberine reached the highest level in 3- year Coptis chinensis, while the contents of magnoflorine and jatrorrhizine hydrochloride were the lowest in three-year Coptis chinensis; and berberine hydrochloride, palmatine hydrochloride, columbamine, epiberberine, and coptisine hydrochloride were the lowest in one-year Coptis chinensis. The hydrochloride of each alkaloid was dissociated in the process of mass spectrometry and appeared in the prototype form. The result obtained by the DESI-MSI method show that berberine and epiberberine were concentrated in the whole-slices section, the distribution area of the one-year sample was the smallest, and the distribution areas of the three- and five-year samples were similar. Jatrorrhizine and columbamine were distributed in the phloem and pith, and the five-year sample distribution area was the largest; palmatine and coptisine were distributed in the phloem and pith, and the one-year sample distribution area was the smallest. Magnoflorine was only distributed in the wood, and the distribution areas in the one-, three-, and five-year Coptis chinensis were similar. Conclusion The accumulation of secondary metabolites in the one-year samples was the least, indicating that the first year is the main stage of the growth and development of Coptis chinensis. The accumulation of secondary metabolites of three-year samples was higher than those of the one-year sample, indicating that the following one to two years are the main stage for the accumulation of secondary metabolites of Coptis chinensis. The five-year plant sample had the highest content of total components, and berberine accumulated the most, which is consistent with the market usage rules of Coptis chinensis being cultivated for at least five years. [ABSTRACT FROM AUTHOR]

To study the sensing process of the human semicircular canals (HSCs) during head rotation, which is difficult to directly measure due to physiological reasons. A 1-BSC (one-dimensional bionic semicircular canal) and 3-BSC were prepared with soft SMPFs (symmetric electrode metal core polyvinylidene difluoride fibers), which could sense deformations similar to human sensory cells. Based on these models, experiments were carried out to study the principle of the HSCs. Deformations of the bionic ampulla (BA) depended on the angular acceleration. Gravity had a strong influence on the deformation of the BA in the vertical plane. When the 3-BSC was subjected to angular acceleration around one of its centerlines, the three BAs all deformed. The deformation of the BAs was linearly related to the angular acceleration. The deformation of the BA in the main semicircular canal was exactly three times that of the other two BAs. [ABSTRACT FROM AUTHOR]

To date, there are three main hypotheses explaining why the human semicircular canals (HSCCs) cannot sense linear accelerations. To further study this issue, we designed a bionic ampulla (BA) instrumented with a symmetrical metal core polyvinylidene fluoride fiber as a bionic sensor, which imitates the structure and function of the human ampulla. The BA was confirmed to have a good sensing ability in experiments with a straight tube. Additionally, we designed a bionic semicircular canal model, a blocking model, and a square model. We compared the perception performance of these three models to test the "density hypothesis," the "closed loop hypothesis," and the "circular hypothesis." The outcomes of these experiments verified the "density hypothesis" and "circular hypothesis," but did not support the "closed loop hypothesis," shedding light on why the HSCC is sensitive to angular acceleration, but not to linear acceleration. [ABSTRACT FROM AUTHOR]

In recent years, 3D printing has received increasing attention from researchers. This technology overcomes the limitations of traditional technologies by printing precise and personalized scaffold with arbitrary shapes, pore structures, and porosities for the applications in various tissues. The cellulose nanocrystal (CNC) is extracted from Humulus Japonicus (HJS) and mixed with poly(ε-caprolactone) (PCL) to prepare a series of CNC/PCL composites for printing. Based on the analysis of the physical and chemical properties of the series of the CNC/PCL composites, an optimal mass ratio of CNC to PCL was obtained. The Solidworks was used to simulate the stretching and compression process of the scaffolds with three different patterns under an external force. The flow of nutrient solution in the scaffolds with different patterns was simulated by ANSYS FLUENT, and then a new optimization scaffold pattern with a concave hexagon shape was advised based on the simulation results. Collectively, the mechanical test results of the material and scaffold confirmed that the optimal filling amount of the CNC was 5%, and the scaffold pattern with concave hexagon shape exhibited better mechanical properties and suitable for the transport of cells and nutrients, which is expected to be more widely used in 3D printing. [ABSTRACT FROM AUTHOR]

An electronic skin (ES) is developed by embedding a liquid-core poly(vinylidene fluoride) fiber into a silicone rubber. The experimental results show that the ES can detect the waveform, frequency, amplitude, and other parameters of the surface vibration pressure. The ES can sense the surface pressure amplitude over a range of 1.5–2.5 kPa and exhibits a sensitivity of 0.0472 fC/Pa when the pressure is less than 60 Pa. The resonant frequency of the ES is 0.4 Hz. The ES can also detect the elongation strain, and its sensitivity is 0.0058 fC/με. The ES has the characteristics of flexibility, high sensitivity, and a wide measuring range. Therefore, the ES can be used as a robot finger skin, which enables the robot to have touch perception capabilities. [ABSTRACT FROM AUTHOR]

Aqueous zinc‐ion batteries (ZIBs) have been considered as prospective alternatives for lithium‐ion batteries, which are able to serve as power sources for next‐generation wearable and flexible devices, owing to the merits of abundant zinc resources and high safety of aqueous electrolyte. However, the lack of suitable cathode materials with flexibility for ZIBs hinders their further application. Herein, a novel cathode material [i.e., MnO2 nanosheet‐assembled hollow polyhedron anchored on carbon cloth (MnO2/CC)] was prepared through a rapid hydrothermal method by using ZIF‐67 as self‐sacrificing template. When tested in an aqueous ZIB, the MnO2/CC delivered a high reversible capacity of 263.9 mAh g−1 at 1.0 A g−1 after 300 cycles, far exceeding those of the commercial MnO2 electrode. More importantly, benefiting from the unique structural advantages, a flexible ZIB assembled based on the MnO2/CC displayed a stable output voltage of 1.53 V and a specific capacity of 91.7 mAh g−1 at 0.1 A g−1 after 30 cycles. It also successfully lit LED bulbs even under different bending angles, showing good flexibility. This research contributes to the development of MnO2‐based cathode materials for high‐performance flexible ZIBs. [ABSTRACT FROM AUTHOR]

Tissue scaffolds need to have anisotropic mechanical properties and a porous structure to meet the needs of different tissues and organs. This report presents results of a study on an especially-designed 3D printing method with oxidized nanocellulose and gelatin, analyzes the servo principle of pneumatic condensing extrusion 3D printer, and proposes a hexagonal algorithm. For the purpose of this study, a printing process file was written by G code, physical and mechanical performance of the 3D scaffolds was evaluated with Solidworks simulation, the porous structure and pressure-pull performance of the printed 3D scaffolds was observed by SEM, and experiments were conducted to measure their bio-compatibility. The study draws the conclusion that scaffolds thus printed have a highly porous structure and anisotropic mechanical properties. [ABSTRACT FROM AUTHOR]

For tissue engineering applications tissue scaffolds need to have a porous structure to meet the needs of cell proliferation/differentiation, vascularisation and sufficient mechanical strength for the specific tissue. Here we report the results of a study of the 3D printing process for composite materials based on oxidized nanocellulose and gelatin, that was optimised through measuring rheological properties of different batches of materials after different crosslinking times, simulation of the pneumatic extrusion process and 3D scaffolds fabrication with Solidworks Flow Simulation, observation of its porous structure by SEM, measurement of pressure-pull performance, and experiments aimed at finding out the vitro cytotoxicity and cell morphology. The materials printed are highly porous scaffolds with good mechanical properties. [ABSTRACT FROM AUTHOR]

As one of the most abundant wild herbs in nature, the Humulus japonicus stem (HJS) is a new low-cost source of cellulosic material. In this work, cellulose nanocrystals (CNCs) were isolated from HJS using acid hydrolysis. The influence of high temperature pretreatment (HT pretreatment) on the properties and yields of these HT-HJS (HJS fibers after HT pretreatment at different temperatures) and HT-CNCs (CNCs prepared from the HT-HJS) was studied. The results showed that there was no variation of the chemical structure among the HT-HJS and HT-CNCs. The thermal stabilities and crystallinities of the HT-HJS were higher than bleached HJS. The average diameters of the HT-CNCs were significantly smaller while the average aspect ratios of them were obviously bigger than the CNCs, and the biggest average aspect ratio of HT140-CNCs (63.40) was almost twice of CNCs (32.00). Compared with the CNCs (70.05%, 212.8 °C), the crystallinity and initial degradation temperature also showed increase for the HT-CNCs and increased up to maximum of 86.93% and 227.5 °C for the HT160-CNCs. [ABSTRACT FROM AUTHOR]

A type of persistent direction-changing positional nystagmus with a null point during head position deflection is known as light cupula syndrome (LCS) in the clinic. To date, the pathogenesis and biomechanical response of human semicircular canals with light cupula syndrome (LCS) (HSCs-LCS) are still unclear. In this study, based on the anatomical structure and size of the one-dimensional human semicircular canal (HSC) and imitating the pathological changes of the endolymph in HSC with LCS, a visual bionic semicircular canal (BSC) with LCS was fabricated using three-dimensional printing technology, hydrogel modification, and target tracking technology. Through theoretical derivation, mathematical models of the HSC-LCS perception process were established. By conducting in vitro experiments on the bionic model, the biomechanical response process of HSC-LCS was studied, and the mathematical models were validated. The results of pulse acceleration stimulation showed that the pathological changes in the density and viscosity of the endolymph could reduce the deformation of the cupula of the BSC-LCS and increase the time constant. The results of the sinusoidal acceleration stimulation showed that the amplitude-frequency gain of the BSC-LCS decreased and the phase difference increased. The BSC-LCS can be used as a tool for pathological research of the HSC-LCS. The results of this study can provide a theoretical basis for clinical diagnosis., (Copyright © 2023 by ASME.)

Canalithiasis is a common vestibular system disorder, which may lead to a specific form of vertigo known as BPPV or top-shelf vertigo. In this paper, based on the actual geometric parameters of the human semicircular canal, we designed a four-fold in vitro one-dimensional semicircular canal model using technologies such as three-dimensional printing, image processing, and target tracking. We investigated the essential characteristics of the semicircular canal, such as the time constant of the cupula and the relationship between the number, density, and size of the canalith and the cupular deformation during canalith settlement. The results showed a linear relationship between the number and size of the canalith and the amount of cupular deformation. We also found that when the number of canaliths reached a particular scale, the interaction between the canaliths exerted an additional disturbance on the cupular deformation ("Z" twist). In addition, we explored the latency time of the cupula during canalith settlement. Finally, we verified that the canaliths had little effect on the frequency characteristics of the semicircular canal by a sinusoidal swing experiment. All the results validate the reliability of our 4-fold in vitro one-dimensional semicircular canal model., (Copyright © 2023 by ASME.)

Background: The relationship between utricle diseases and structural lesions is not very clear in the clinic due to the complexity and delicacy of the utricle structure. Therefore, it is necessary to study the perception mechanism of the utricle., Methods: Imitating the sensory cells in the macula of the utricle, a symmetrical metal core PVDF fiber (SMPF) was designed as a bionic hair sensor to fabricate a bionic macula (BM), a bionic macula with sand (BMS) and a bionic utricle (BU). Then experiments were carried out on them., Results: This indicated the SMPF sensor can sense its bending deformation, which was similar to the sensory cell. The amplitude of the output charges of the SMPF in BMS and BU were significantly improved. The SMPF, whose electrode boundary was perpendicular to the impact direction, exhibited the largest output charges., Conclusion: The presence of otoliths and endolymph can improve the sensing ability of the utricle. The human brain can judge the direction of head linear accelerations based on the location of the sensory cell in the macula that produces the largest nerve signals. This provides a possibility of studying utricle abnormal functions in vitro in the future.

Mammalian whiskers can perceive obstacles and airflows. In this study, an electronic whisker (E-whisker) sensor was designed and fabricated by setting a PVDF ring with symmetrical electrodes on the root of a fiber beam. Vibration displacements with different waveforms were applied at the free end of the E-whisker beam to study the relationship between the vibration displacements and the output signals. The E-whisker protrusion sensing ability was investigated by driving it to sweep through the surface of a base platform. A static E-whisker beam and a swinging E-whisker were then separately placed in a wind tunnel to detect the airflow perception of the sensor. The experimental results suggested that the E-whisker could sense the frequencies and amplitudes of displacements at its free end, the height and width of a platform or the heights of other irregular protrusions; the static E-whisker could sense the magnitude or direction of an impact airflow, while the swinging E-whisker could sense the magnitude of a constant airflow. Thus, this kind of E-whisker could perceive the environment and airflow through touch sensation and could be used as a physical model to study the principles and abilities of animal whiskers to perceive obstacles and airflows., (© 2021 IOP Publishing Ltd.)

Aqueous zinc-ion batteries (ZIBs) have been considered as prospective alternatives for lithium-ion batteries, which are able to serve as power sources for next-generation wearable and flexible devices, owing to the merits of abundant zinc resources and high safety of aqueous electrolyte. However, the lack of suitable cathode materials with flexibility for ZIBs hinders their further application. Herein, a novel cathode material [i.e., MnO 2 nanosheet-assembled hollow polyhedron anchored on carbon cloth (MnO 2 /CC)] was prepared through a rapid hydrothermal method by using ZIF-67 as self-sacrificing template. When tested in an aqueous ZIB, the MnO 2 /CC delivered a high reversible capacity of 263.9 mAh g -1 at 1.0 A g -1 after 300 cycles, far exceeding those of the commercial MnO 2 electrode. More importantly, benefiting from the unique structural advantages, a flexible ZIB assembled based on the MnO 2 /CC displayed a stable output voltage of 1.53 V and a specific capacity of 91.7 mAh g -1 at 0.1 A g -1 after 30 cycles. It also successfully lit LED bulbs even under different bending angles, showing good flexibility. This research contributes to the development of MnO 2 -based cathode materials for high-performance flexible ZIBs., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Tissue scaffolds need to have anisotropic mechanical properties and a porous structure to meet the needs of different tissues and organs. This report presents results of a study on an especially-designed 3D printing method with oxidized nanocellulose and gelatin, analyzes the servo principle of pneumatic condensing extrusion 3D printer, and proposes a hexagonal algorithm. For the purpose of this study, a printing process file was written by G code, physical and mechanical performance of the 3D scaffolds was evaluated with Solidworks simulation, the porous structure and pressure-pull performance of the printed 3D scaffolds was observed by SEM, and experiments were conducted to measure their bio-compatibility. The study draws the conclusion that scaffolds thus printed have a highly porous structure and anisotropic mechanical properties.

For tissue engineering applications tissue scaffolds need to have a porous structure to meet the needs of cell proliferation/differentiation, vascularisation and sufficient mechanical strength for the specific tissue. Here we report the results of a study of the 3D printing process for composite materials based on oxidized nanocellulose and gelatin, that was optimised through measuring rheological properties of different batches of materials after different crosslinking times, simulation of the pneumatic extrusion process and 3D scaffolds fabrication with Solidworks Flow Simulation, observation of its porous structure by SEM, measurement of pressure-pull performance, and experiments aimed at finding out the vitro cytotoxicity and cell morphology. The materials printed are highly porous scaffolds with good mechanical properties.