Search

Dendrobium officinale leaves (DOL) contain many active ingredients with various pharmacological effects, but are still ineffectively utilized. To investigate the feasibility of developing DOL as a feed additive, it is necessary to determine whether dietary supplementing DOL had any effect on meat quality and flavor. Our results showed that supplementation with DOL decreased the shear force while increased the pH and fat content in breast meat. Meat from DOL-fed chickens had higher levels of n-3 polyunsaturated fatty acids (PUFAs) and n-6 PUFAs, but lower n-6/n-3 ratios. Moreover, volatile compounds profile indicated that contents of aldehydes, including hexanal, pentanal, and heptanal, etc.), which were identified as the key volatile compounds in chicken meat, exhibited noteworthy rise in DOL intake groups. Octanal, 1-octen-3-ol, and 2-pentylfuran also contributed greatly to the meat overall aroma. These data provide a foundation for the comprehensive utilization of DOL as a feed additive with antibiotic substitution potential.

In this study, a phase-field scheme that rigorously obeys conservation laws and irreversible thermodynamics is developed for modeling stress-corrosion coupled damage (SCCD). The coupling constitutive relationships of the deformation, phase-field damage, mass transfer, and electrostatic field are derived from the entropy inequality. The SCCD localization induced by secondary phases in Mg is numerically simulated using the implicit iterative algorithm of the self-defined finite elements. The quantitative evaluation of the SCCD of a C-ring is in good agreement with the experimental results. To capture the damage localization, a micro-galvanic corrosion domain is defined, and the buffering effect on charge migration is explored. Three cases are investigated to reveal the effect of localization on corrosion acceleration and provide guidance for the design for resistance to SCCD at the crystal scale.

Abstract Artificial biomaterials with dynamic mechano-responsive behaviors similar to those of biological tissues have been drawing great attention. In this study, we report a TiO2-based nanowire (TiO2NWs) scaffolds, which exhibit dynamic mechano-responsive behaviors varying with the number and amplitude of nano-deformation cycles. It is found that the elastic and adhesive forces in the TiO2NWs scaffolds can increase significantly after multiple cycles of nano-deformation. Further nanofriction experiments show the triboelectric effect of increasing elastic and adhesive forces during the nano-deformation cycles of TiO2NWs scaffolds. These properties allow the TiO2NW scaffolds to be designed and applied as intelligent artificial biomaterials to simulate biological tissues in the future.

Abstract Stretchable electronics have the unique capability of 3D (three dimensional) deformation, overcoming the brittleness of traditional inorganic electronics. However, during large deformations, different scale strains between the rigid and stretchable components lead to mismatch, causing interconnect failures. Therefore, the development of the rigidity‐programmable substrate with effective strain shielding capabilities has become a research hotspot. Furthermore, the exponential growth in electronic density presents challenges in the circuit design of stretchable electronics. The urgent need is to develop highly integrated stretchable electronic systems. In this study, a highly integrated stretchable pulse sensor with effective strain shielding capabilities using hybrid 3D printing technology is developed, which comprises electronic chips, a rigidity‐programmable substrate/encapsulation layer printed by using PSC (polydimethylsiloxane/silica‐nanoparticles composite)‐based ink, and LM (liquid metal)‐based 3D circuits. First, the PSC‐based ink is optimized to enhance the strain shielding effectiveness of the rigidity‐programmable substrate. Meanwhile, 3D printing parameters are optimized to achieve high printing precision with minimum line widths below 100 µm. The resulting stretchable pulse sensor demonstrated good mechanical and electrical stability under complex 3D deformations, including bending, twisting, and stretching. The PSC region strain of the sensor is only ≈2% when the global strain is up to ≈65%, which exhibited effective strain shielding capabilities.

This study explored the development of polyvinylpyrrolidone (PVP)–honey-gel (PHG) through 3D printing, aiming to develop a multifunctional bio-tape with adhesive and degradable properties. Based on the potential of honey to promote wound healing due to its antibacterial and anti-inflammatory properties, a PVP–honey-based 3D printing ink was developed by combining honey and PVP to create PHG through 3D printing technology that can form a film with strong adhesion and flexibility. First, the chemical–physical properties of PHG and its 3D printing performance were characterized. The line width achievable in 3D printing for the PHG line can extend to ∼100 µm. In addition, the adhesive properties of the PHG film were evaluated by using a 180° peeling test on various materials (glass, copper, wood, and pig skin), highlighting its potential for diverse applications. Finally, the application of the PHG film as a bio-tape was demonstrated through a successful animal experiment on a rabbit’s skin wound. Due to its adhesive and degradable properties, the bio-tape exhibited 3D conformability and ease of removal without residue.

This study investigates the storage life of particle-filled polymer composites (PFPCs) under the influence of aging effects. High-temperature accelerated aging tests were conducted at 60 °C, 70 °C, and 80 °C for various days to analyze the impact of aging time and temperature on the mechanical behavior of the materials. A predictive model for crosslink density was established using the Arrhenius equation, and the relationship between crosslink density and relaxation modulus was determined based on polymer physics theory. On this basis, a viscoelastic constitutive model that incorporates aging effects was developed. Structural analyses of a PFPC column with a length of 2.3 m and outer diameter of 1.8 m were performed using the UMAT subroutine in ABAQUS. Subsequently, a safety margin assessment method based on dewetting strain was employed to predict the storage life of the PFPC column. The results indicate that the aging viscoelastic constitutive model effectively characterizes the hardening effects caused by aging in the composites during storage. The storage life for the PFPC column considering aging effects decreases from 22 years to 19 years compared to models that ignore such effects. This approach provides a reference for estimating the storage life of PFPC columns considering aging effects.

Carbon fiber resin-based composite materials are widely employed in the manufacturing of composite shells. During the curing process, the temperature gradients and cure degree gradients make it easy to generate thermal strains in both carbon fibers and resin, with the resin experiencing cure shrinkage strain due to the curing reaction, ultimately leading to residual stresses and strains. In this paper, a three-dimensional thermo–chemo–mechanical coupled curing model of the composite shell was established based on a resin test, and the changes of temperature, curing degree, residual stress, and strain during the solidification of the composite shell were investigated. First, the curing property parameters and elastic modulus of HCM-2184 resin were obtained through a curing dynamic test and a tensile test. Then, considering the heat release and shrinkage reaction of solidification, a coupled thermo–chemo–mechanical curing model was developed with the CHILE (α) elastic model, and the curing process of the composite shell was simulated numerically. The results show that the resin used in the test belongs to the autocatalytic reaction. For thin composite shells, the heat accumulation inside the shell during curing is not obvious. During the curing process, the curing shrinkage behavior of the resin is an important factor for the generation of residual stress and residual strain.

A novel type of tubular structure with negative Poisson's ratio based on gyroid-type triply periodic minimal surfaces (TPMSs) is proposed in this study. This work is an attempt to design auxetic tubular structures based on TPMS. A series of auxetic tubular structures were designed and then fabricated using laser power bed fusion. Compressive behaviours of the fabricated auxetic tubular structures were investigated using experimental and numerical methods. To obtain optimal designs of tubular structures with controllable auxetic properties, the influence of several parameters were investigated comprehensively. Subsequently, several graded auxetic tubular structures were designed based on the parametric analysis and studied numerically. The mechanical properties of the tubular structures could be controlled effectively using the proposed approach. The proposed method can be used for guiding the design and optimisation of auxetic tubular structures, showing excellent potential for various applications such as biomedical devices, vehicle crashworthiness, and protective engineering.

Triply periodic minimal surfaces (TPMSs) have demonstrated significant potential in lattice structure design and have been successfully applied across multiple industrial fields. In this work, a novel lattice structure with tunable anisotropic properties is proposed based on two typical TPMS types, and their mechanical performances are studied both experimentally and numerically after being fabricated using a polymer 3D printing process. Initially, adjustments are made to the original TPMS lattice structures to obtain honeycomb lattice structures, which are found to possess significant anisotropy, by utilizing numerical homogenization methods. Based on this, a continuous self-twisting deformation is proposed to change the topology of the honeycomb lattice structures to largely tune the mechanical properties. Quasi-static compression experiments are conducted with different twisting angles, and the results indicate that self-twisting can affect the mechanical properties in specific directions of the structure, and also enhance the energy absorption capacity. Additionally, it mitigates the risk of structural collapse and failure during compression while diminishing structural anisotropy. The proposed self-twisting strategy, based on honeycomb lattice structures, has been proven valuable in advancing the investigation of lattice structures with largely tunable mechanical properties.

BackgroundThe Dendrobium officinale leaves (DOL) is an underutilized by-product with a large biomass, which have been shown to exhibit immunomodulatory and antioxidant functions. The purpose of this research was to investigate the effects of DOL on broiler growth performance, antioxidant status, immune function, and gut health.MethodsOne hundred and ninety-two 1-day-old chicks were selected and divided into 4 groups at random, 6 replicates for each group and 8 in each. Chicks were given a basal diet supplemented with different amounts of DOL: 0% (control group, NC), 1% (LD), 5% (MD), or 10% (HD). During the feeding trial (70 days), broiler body weight, feed intake, and residual feeding were recorded. On d 70, 12 broilers from each group were sampled for serum antioxidant and immune indexes measurement, intestinal morphological analysis, as well as 16S rRNA sequencing of cecal contents and short-chain fatty acid (SCFA) determination.ResultsIn comparison to the NC group, the LD group had greater final body weight and average daily gain, and a lower feed conversion ratio (p < 0.05, d 1 to 70). However, in MD group, no significant change of growth performance occurred (p > 0.05). Furthermore, DOL supplementation significantly improved the levels of serum total antioxidant capacity, glutathione peroxidase, superoxide dismutase, and catalase, but reduced the level of malondialdehyde (p < 0.05). Higher serum immunoglobulin A (IgA) content and lower cytokine interleukin-2 (IL-2) and IL-6 contents were observed in DOL-fed broilers than in control chickens (p

Carbon fiber reinforced composites (CFRP) are susceptible to hidden damage from low velocity external impacts during their service life. To ensure the proper monitoring of the state of the composites, it is crucial to predict the location of an impact event. In this paper, fiber Bragg grating (FBG) sensors are affixed to the surface of a carbon fiber composite tube, and an optical sensing interrogator is used to capture the central wavelength shift of the FBG sensors due to low-velocity impacts. A discrete wavelet transform is used for noise reduction in the response signals. Then, the differences in the captured response signals of the FBG sensors at different locations of the impact were analyzed. Moreover, two methods were implemented to predict the location of low-velocity impacts, according to the differences in the captured response signals. The BP neural network-based method utilized three data sets to train the neural network, resulting in an average localization error of 20.68 mm. In contrast, the method based on error outliers selected a specific data set as the reference dataset, achieving an average localization error of 13.98 mm. The comparison of the predicted results shows that the latter approach has a higher predictive accuracy and does not require a significant amount of data.

In this study, the aging performance of particle-filled polymer composites (PFPCs) under thermo-oxidative conditions was investigated on multiple scales. High-temperature-accelerated tests were conducted to analyze the effects of aging time and temperature. A representative volume element (RVE) model was established for the PFPCs using a random particle-filling algorithm. A predictive model for the crosslink density was conducted based on the closed-loop chain reaction of polymer oxidation. According to the theory of polymer physics, the relation between the crosslink density and matrix modulus was determined. The particle/matrix interface in the RVE model was represented by the cohesive zone model (CZM). The parameters of the CZM were determined by the inversion techniques. Then, a comprehensive multiscale RVE model was constructed, which was applied to predict the modulus and dewetting strain of the aged PFPCs. The predicted results show good agreement with the test results, which verifies the reliability of our model.

Abstract In general, tooth wear is difficult to be noticed until it leads to toothache in vivo. Developing a dynamic dental wear monitoring system to predict tooth wear in daily life is a necessity. The translation between complex surface wear morphology and corresponding digital signal source is a technical limitation to develop this kind of monitoring system. Microwear texture analysis has been widely employed in predicting diet by a palaeontologist. The main question is whether the microwear texture analysis has potential development space to develop a sensor for monitoring tooth wear. According to obtained results, the microwear texture analysis had enough sensitivity to display the surface morphology variations for different chewing foods and various angles. The corresponding sensitive digital signal of tooth microwear surface morphology makes it possible to develop a dental microwear sensor.

Glycine-aspartic acid‑serine-leucine (GDSL) type lipases/esterases genes play critical roles in plant development and are related to the responses to abiotic and biotic stress. However, little is known about the GDSL family in pear (Pyrus spp.). Studies have shown GDSL-domain proteins play key roles in suberin deposition. Suberin deposition in the fruit epidermis, also called russeting, is an important defect that negatively affects consumer's appeal in some fruit species, such as pear, apple and grapevine. Fruit russeting is mainly associated with cuticle microcracking and suberin accumulation in the inner part of the epidermal cell walls. To gain insight into the role of the GDSL gene family in suberin deposition and russet development in pear, we performed a genome-wide characterization of the GDSL family, including their identification, chromosomal localization, phylogenetic relationships, and expression patterns, in different tissues/organs in pear. One hundred and thirteen GDSL-type lipases/esterases genes were identified in the pear genome, and a phylogenetic analysis revealed that GDSL family can be classified into four distinct groups. Thirty GDSL genes were co-expressed with five homolog pear genes of three well-known suberin biosynthesis Arabidopsis genes (AtGPAT5, AtASFT, and AtCYP86B1) in the transcriptional co-expression network during pear fruit development. Among the 30 co-expressed GDSL genes, twelve genes were further analyzed by quantitative Real-time PCR, and the results showed the expression levels of the 12 genes were different between the russet exocarp and green exocarp of sand pear at different fruit development stages. Our study provides a detailed overview of the GDSL gene family and lays the foundation for future functional characterization of GDSL genes in P. bretschneideri.

In this study, the propagations of surface acoustic waves (SAWs) in two-dimensional solid/fluid phononic crystal (PC) structures were investigated. The PC structures are composed of a periodic sequence of hollow pillars deposited on a semi-infinite substrate, which can be filled with various kinds/heights of fluid. Finite element analysis was used to study the characteristics of SAW bandgaps for the unit cell of PCs. The results showed that the distribution of bandgaps varies with the fluid height. Additionally, the change of bandgaps is more sensitive to mercury than water. Furthermore, transmission properties of SAWs for the PCs filled with different mercury heights are analyzed. It can be found that the PCs can inhibit the propagation of SAWs with a frequency corresponding to the bandgaps validly. Meanwhile, comparing with the transmission spectra, it could be concluded that the transmission troughs shift to lower frequency overall as the mercury heights increase. The results obtained in this study are instructive and meaningful for the practical design of tunable SAW PCs.

The present work investigates the thermally controlled deformation characteristics in temperature-sensitive hydrogels bilayers. The free energy density for temperature-sensitive hydrogels is modified, upon which the finite element model is developed and implemented through user-defined material subroutine UHYPER in the commercial software ABAQUS. The modified UHYPER implementation allows for more vividly depicting the continuous deformation in phase temperature region for temperature-sensitive hydrogels. Several thermally controlled cases of temperature-sensitive hydrogel including grippers, self-folding boxes, thermally driven origami are presented to illustrate a wide array of complex interesting applications or phenomena. Furthermore, we develop a simple model to theoretically calculate the bending angle of the temperature-sensitive hydrogel bilayers, which has been validated by the finite element simulation results. Our study can provide more insights for optimal design in thermally controlled hydrogels structures.

In hydrogel-based tissue engineering, channel network is an efficient structure for transporting nutrients/oxygen to support cell survival and construct living tissues in vitro. 3D printing can create complex hydrogel-based tissue constructs, however, due to the weak mechanical properties of hydrogel bioinks, cell-laden hydrogel constructs with effective channel networks are difficult to be directly printed. Here, an easy sacrificial 3D printing method based on commercial desktop 3D printer and water-soluble polyvinyl alcohol (PVA) to construct effective hydrogel channel networks is introduced. Specifically, i) commercial PVA consumables are printed to be sacrificial templates; ii) gelatin methacryloyl (GelMA) solution is cast to encapsulate the sacrificial template; iii) the sacrificial template is dissolved to form channel networks. PVA is a water-soluble sacrificial material with sufficient dissolution time and high mechanical strength, which can avoid the disadvantages of classic sacrificial materials (sugar and Pluronic F127). High roundness of printed PVA filaments results in high roundness of the channel networks. The interconnected channel networks accelerate the supply of oxygen/nutrients and promote cell growth. And with a period of culture, the higher the channel networks density, the better the cell growth. Additionally, PVA sacrificial templates have high stability and long-term preservation, facilitating transportation, circulation and use, which is conducive to the manufacturing and promotion of hydrogel-based constructs with channel networks. Taken together, our easy strategy of manufacturing hydrogel constructs with channel networks has broad application prospects, such as 3D cell culture, construction of functional tissue in vitro or tissue repair in vivo etc.

Fragaria viridis exhibits S-RNase-based gametophytic self-incompatibility, in which S-RNase is the major factor inhibiting pollen tube growth. However, the pathways involved in and the immediate causes of the inhibition of pollen tube growth remain unknown. Here, interactive RNA sequencing and proteome analysis revealed changes in the transcriptomic and proteomic profiles of F. viridis styles harvested at 0 and 24 h after self-pollination. A total of 2,181 differentially expressed genes and 200 differentially abundant proteins were identified during the pollen development stage of self-pollination. Differentially expressed genes and differentially abundant proteins associated with self-incompatible pollination were further mined, and multiple pathways were found to be involved. Interestingly, the expression pattern of the transcription factor FviYABBY1, which is linked to polar growth, differed from those of other genes within the same family. Specifically, FviYABBY1 expression was extremely high in pollen, and its expression trend in self-pollinated styles was consistent with that of S-RNase. Furthermore, FviYABBY1 interacted with S-RNase in a non-S haplotype way. Therefore, FviYABBY1 affects the expression of polar growth-related genes in self-pollen tubes and is positively regulated by S-RNase.

In this study, we developed a novel multi-scale model to predict the aging performance of particle-filled polymer composites (PFPCs) under thermo-oxidative aging conditions. To investigate the aging behavior, high-temperature accelerated aging tests were conducted in combination with macroscopic and microscopic characterization. At the microscopic level, the crosslinking density of the polymer matrix is calculated using the closed-loop chain reaction of polymer oxidation. In addition, the theory of polymer physics was used to determine the relationship between crosslinking density and elastic modulus. Relationships between elastic modulus and dewetting strain were analyzed at the macroscopic level. Based on the observations and analyses, a multi-scale model was developed to predict the aging performance of PFPCs. The predicted results show good agreement with the test results, which verifies the reliability of the model.

Triply periodic minimal surfaces (TPMS) - based porous structures have been universally adopted for mimicking the properties of bone scaffolds due to their interconnected geometries with smooth surfaces and controllable pores. To further increase the versatility and controllability, an enhanced porous scaffold based on TPMS is proposed. The enhanced pores with different sizes are designed onto three types of TPMS-based scaffolds and then additively manufactured through laser powder bed fusion (LPBF). To investigate the manufacturability, various approaches are used and the results confirm that morphological features of printed samples are identical to the designed ones. As for mechanical properties, the results from the compression tests show that the elastic modulus and compressive strength of enhanced porous scaffolds are 2.0 GPa to 5.1 GPa and 86.7 MPa to 264.2 MPa respectively, which are all in the range of human bones. In terms of permeability, both experiments and simulation indicate that the designed scaffolds have 40%−150% improvement compared to scaffolds without enhanced pores. The biocompatibility of the scaffolds is further verified by in vitro studies. The results demonstrate the suitability of the proposed enhanced porous scaffolds for bone implants, and it will facilitate the design of more effective porous materials.

Abstract A layer of micro‐sized periodontal membrane can buffer most chewing forces to protect the interface between the natural tooth root and alveolar bone. Artificial dental implants usually direct contact onto the alveolar bone without a buffer layer, which increases the risk of surface damage. The main purpose of this work was the bionic design of a flexible layer of nanowire scaffold on a titanium implant surface according to the function of the periodontal membrane. Millions of nanowires were woven into a superhydrophilic layer of porous scaffold. The evolution of mechanical properties displayed that the biomimetic nanowire scaffold could absorb a maximum of about 1.59 KJ energy per square centimeter by low‐speed impact. The minimum tensile strength of one nanowire was 2 GPa. A biomimetic flexible periodontal membrane connection functioning between the natural tooth root and alveolar bone has great potential value for developing advanced artificial dental implants for dental restorations.

We introduce smaller artificial factors into the elastic constants matrix and manage to make Mindlin first-order plate theoryequations of motions coupled for a uniform and integrated analysis. The energy distributions of the five coupled modes are obtained and all the five vibration modes are identified through the energy calculation. This analytical approach based on artificial couplings of vibration modes suggests that all vibration modes of structural components can be analyzed through the same procedure and computer code if the right elastic constants are modified and the mode identification can be done with the energy method. This is a new technique to study multimode vibrations of structures in a broad frequency range with just one procedure and calculation tool for simplification.

ABSTRACT: It is well-known that Rayleigh wave, also known as surface acoustic wave (SAW), solutions in semi-infinite solids are plane waves with signatory properties like the distinct velocity and exponentially decaying deformation in the depth. Applications of Rayleigh waves are focused on the deformation and energy in the vicinity of surface of solids and less loss in the propagation. A generalized model of Rayleigh waves in axisymmetric mode is established and solutions are obtained with cylindrical coordinates. It is found that the Rayleigh waves also propagate in the axisymmetric mode with slow decay in radius, confirming the existence of surface acoustic waves is irrelevant to coordinate system. On the other hand, the solutions can be treated as plane waves in regions far away from the source. Furthermore, the particle trajectory of axisymmetric SAW is a line with constant slope rather than the signatory ellipse in Cartesian coordinate case. Keywords: Axisymmetric, Rayleigh wave, Solid, Propagation, Velocity

Conductive polymers and their composites have been widely applied in different applications, including sensing applications. Herein, we constructed a conductive composite of polypropylene, carbon black, and multi-walled carbon nanotubes (PP/CB/MWCNTs) to experimentally study its sensing behaviors in a humid thermal environment. The as-synthesized PP/CB/MWCNT composite polymer was immersed in simulated sweat in deionized water at 67 °C. Regarding their electrical and mechanical properties, different experimental parameters, such as cyclic loading and hygrothermal aging, were investigated by recording the mass changes, carrying out strain sensing experiments, and performing dynamic mechanical analyses before and after the immersion test. The results reveal that the filler content improved the rate of water absorption but decreased at higher concentrations of the solution. The sensitivity of the material decreased by up to 53% after the hygrothermal ageing and cyclic loading. Moreover, the sensitivity under cyclic compression loading decreased with an increasing immersion time, qualitatively illustrated by an effective quantum tunneling effect and conducting path model. Finally, hygrothermal aging reduced the composite’s glass transition temperature. This reduction was the most significant for specimens immersed in deionized water, ascribed to the moisture absorption, reducing the molecular chain activity.

In this paper, we present a novel reduced Galinstan-based microfluidic energy harvester, which can converse kinetic energy to electricity from an arbitrary vibration source. Firstly, the wetting behaviors of reduced Galinstan are performed, which shows a robust impact effect on polymer substrates. Moreover, the electric circuit model of the reduced Galinstan-based energy harvester is made and discussed by the use of the EDLCs (electrical double layer capacitors). After modeling, the microfluidic energy harvester with coplanar microfluidic channels is designed and fabricated. Finally, the performance of the microfluidic energy harvester is investigated, which can harvest multi-direction vibration energy. The experiment results demonstrate that the novel reduced Galinstan-based microfluidic energy harvester is suitably and uniquely applied in a complex vibration environment.

The propagation of surface acoustic waves in two types of tunable magneto-electro-elastic phononic crystal structures is investigated, for which Terfenol-D rods are vertically deposited on the piezoelectric substrate or embedded in the piezoelectric substrate. The bandgaps of the phononic crystal structures are analyzed by using the finite element method considering the nonlinear physical characteristics of Terfenol-D under a magnetic field and compressive pre-stress. Furthermore, through a detailed discussion of the calculated results, it is shown that the bandgaps of surface acoustic waves can be enlarged and new bandgaps will appear under an appropriate magnitude of magnetic field and compressive stress. Therefore, the present numerical model may provide relevant guidance for adjusting the bandgaps of surface acoustic waves in a two-dimensional magneto-electro-elastic phononic crystal.

Melt electro writing (MEW) provides three-dimensional (3D) printing porous scaffolds with well-defined geometrical features of ultrafine fibers in the tissue engineering. Scaffolds with adjustable Poisson's ratio are more suitable in certain biological applications for mimicking the behavior of native tissue mechanics. However, it is still a challenging issue to tune the Poisson's ratio. In order to resolve this problem, a new method is proposed in the present study to design and fabricate tunable auxetic scaffolds through altering the printing configurations in the MEW. Patterns with thick fibers are designed using specific geometries and then these patterns are utilized to tune the Poisson's ratio based on the intended deformation mechanism. Moreover, the electrospun thin fibers are used to fill the unit cell of auxetic lattice structures for promoting the cell growth. Investigating the mechanical characteristics of the fabricated scaffolds demonstrates that the Poisson's ratio of the scaffold can be effectively tuned. Furthermore, cell sense and response to the fabricated scaffolds are studied. Obtained results indicate that the proposed approach can potentially be applied in a wide variety of biomedical applications.

Melt electrospinning writing (MEW) has recently emerged as a direct three-dimensional (3D) writing approach for the fabrication of orderly porous structures with well-defined geometrical features. In particular, it is widely used to produce tissue engineering (TE) scaffolds. The diameter of the electrospun fibers strongly affects the achievable resolution and consequently influences several other physical and mechanical properties of the fabricated scaffolds. However, compared to general extrusion-based additive manufacturing (E-AM) techniques, the factors influencing the size of the fibers are more complex owing to the presence of the electric field. In this study, several critical and effective process parameters in the MEW process are first investigated and then optimized to achieve the desired fiber diameter. Moreover, the fiber placement accuracy, which is essential for fabricating heterogeneous scaffolds with highly accurate features, is studied by considering the “lag effect” due to relative movement between the collector and the spinneret. In addition, an optimization strategy is proposed to avoid the error introduced by the “lag effect” while achieving the desired fiber diameter. This strategy can be used to adaptively control the process parameters. Finally, the proposed approach is validated and adopted for fabricating heterogeneous scaffolds to culture cells. Keywords: Melt electrospinning writing, Additive manufacturing, Heterogeneous scaffolds, Lag effect, Path planning

Strawberry species (Fragaria spp.) are known as the “queen of fruits” and are cultivated around the world. Over the past few years, eight strawberry genome sequences have been released. The reuse of these large amount of genomic data, and the more large-scale comparative analyses are very challenging to both plant biologists and strawberry breeders. To promote the reuse and exploration of strawberry genomic data and enable extensive analyses using various bioinformatics tools, we have developed the Genome Database for Strawberry (GDS). This platform integrates the genome collection, storage, integration, analysis, and dissemination of large amounts of data for researchers engaged in the study of strawberry. We collected and formatted the eight published strawberry genomes. We constructed the GDS based on Linux, Apache, PHP and MySQL. Different bioinformatic software were integrated. The GDS contains data from eight strawberry species, as well as multiple tools such as BLAST, JBrowse, synteny analysis, and gene search. It has a designed interface and user-friendly tools that perform a variety of query tasks with a few simple operations. In the future, we hope that the GDS will serve as a community resource for the study of strawberries.

A few simple polymeric microsystems, such as microcantilever sensors, have recently been developed for the preliminary screening of cardiac toxicity. The microcantilever deflection produced by a change in the cardiomyocyte (CM) contraction force is important for understanding the mechanism of heart failure. In this study, a new numerical model is proposed to analyze the contractile behavior of CMs cultured on a perforated microcantilever surface for improving the performance of the microcantilever sensor. First, the surface traction model is used to investigate the bending displacement of the plain microcantilever. In order to improve the bending effect, a new numerical model is developed to analyze the bending behavior of the perforated microcantilever covered with CMs. Compared with the designed molds, the latter yields better results. Finally, a simulation analysis is proposed based on a finite element method to verify the presence of a preformed mold. Moreover, the effects of various factors on the bending displacement, including microcantilever size, Young’s modulus, and porosity factor, are investigated. Both the simulation and numerical results have good consistency, and the maximum error between the numerical and simulation results is not more than 3.4%, even though the porosity factor reaches 0.147. The results show that the developed mold opens new avenues for CM microcantilever sensors to detect cardiac toxicity.

Functional graded materials are gaining increasing attention in tissue engineering (TE) due to their superior mechanical properties and high biocompatibility. Triply periodic minimal surface (TPMS) has the capability to produce smooth surfaces and interconnectivity, which are very essential for bone scaffolds. To further enhance the versatility of TPMS, a parametric design method for functionally graded scaffold (FGS) with programmable pore size distribution is proposed in this study. Combining the relative density and unit cell size, the effect of design parameters on the pore size was also considered to effectively govern the distribution of pores in generating FGS. We made use of Gyroid to generate different types of FGS, which were then fabricated using selective laser melting (SLM), followed by investigation and comparison of their structural characteristics and mechanical properties. Their morphological features could be effectively controlled, indicating that TPMS was an effective way to achieve functional gradients which had bone-mimicking architectures. In terms of mechanical performance, the proposed FGS could achieve similar mechanical response under compression tests compared to the reference FGS with the same range of density gradient. The proposed method with control over pore size allows for effectively generating porous scaffolds with tailored properties which are potentially adopted in various fields.

In the paper, a phononic crystal plate composed of a magnetorheological elastomer with adjustable band gaps in the low frequency range is constructed. The dispersion relations of Lamb waves are studied by the supercell plane wave expansion method. The transmission responses as well as the displacement fields of Lamb waves are calculated by the finite element method. The influence of geometric parameters on the band gaps, the regulation effect of the volume ratio of Fe particles and the bias magnetic field on the band gaps are analyzed. Based on the numerical results, we find that the volume ratio of Fe particles and the magnetic field affect the band gap effectively. The location and width of the band gaps can be adjusted within a broad frequency range by varying the geometric parameters and magnetic field. We can control the band gap, achieve an appropriate and wide low band gap by selecting proper geometric parameters and applying an external contactless magnetic field to deal with complicated and changeable engineering environment. The results are useful for understanding and optimizing the design of composite vibration isolation plates.

A new type of sheet porous structures with functionally gradients based on triply periodic minimal surfaces (TPMS) is proposed for designing bone scaffolds. The graded structures were generated by constructing branched features with different number of sheets. The design of the structure was formulated mathematically and five types of porous structure with different structural features were used for investigation. The relative density (RD) and surface area to volume (SA/V) ratio of the samples were analyzed using a slice-based approach to confirm their relationships with design parameters. All samples were additively manufactured using selective laser melting (SLM), and their physical morphologies were observed and compared with the designed models. Compression tests were adopted to study the mechanical properties of the proposed structure from the obtained stress–strain curves. The results reveal that the proposed branched-sheet structures could enhance and diversify the physical and mechanical properties, indicating that it is a potential method to tune the biomechanical properties of porous scaffolds for bone tissue engineering (TE).

In the present study, piezoelectric resonators under lateral field excitation (LFE) based on a LiTaO3 single crystal are modeled and analyzed. An electrically forced vibration study is employed to acquire the motional capacitance curve and vibration mode shapes. A finite element approach is utilized to investigate the influences of some basic parameters, such as the electrode/plate mass ratio, electrode gap, and electrode width on resonance characteristics. In addition, the design criteria for the gap and width of the electrode of the LiTaO3 LFE resonators are obtained by analyzing the effects of those parameters on vibration strain distributions. The obtained results are essential for designing LFE piezoelectric resonators by using a LiTaO3 single crystal.

Flexoelectricity is a novel kind of electromechanical coupling phenomenon that is prevalent in all solid dielectrics and usually of vital importance in nanostructures and soft materials. Although the fundamental theory of flexoelectric solids and related beam or plate theories were extensively studied in recent years, the coupling effect of flexoelectricity and piezoelectricity in piezoelectric nanostructures has not been completely clarified yet. In the present work, a geometrically nonlinear piezoelectric plate model is established with a focus on the coupling effect. The constitutive equations for piezoelectric plates are derived under both the electrically short-circuit and open-circuit conditions. It is found that due to the coupling between flexoelectricity and piezoelectricity, stretching-bending coupling stiffness arises in the homogeneous plate and its specific value relies on the applied electrical boundary conditions. The effects of the flexoelectric-piezoelectric coupling on the effective mechanical behavior and the electromechanical behavior of nanobeams and nanoplates are also discussed. The developed model and presented results are expected to benefit the design and analysis of piezoelectric and flexoelectric devices and systems.

In the present study, pseudo lateral-field-excitation (LFE) bulk acoustic wave characteristics on LGT crystals are investigated to increase the sensitivity of LFE devices on the liquid characteristic variations. The cut orientation of LGT crystals for pseudo-LFE is investigated and verified experimentally. For an LFE device in the pseudo-LFE mode, the thickness shear mode wave is excited by the thickness field rather than the lateral field. The present work shows that when the (yxl) 13.8° LGT plate is excited by the electric field parallel to the crystallographic axis x, it operates in the pseudo-LFE mode. Moreover, characteristics of devices including the sensitivity and impedance are investigated. The present work shows that sensitivity of LFE devices to variation of the conductivity and permittivity of the aqueous solution are 9 and 3.2 times higher than those for AT-cut quartz crystal based devices, respectively. Furthermore, it has been found that the sensitivity of the LGT LFE sensor to liquid acoustic viscosity variations is 1.4 times higher than the one for the AT-cut quartz sensor. The results are a critical basis of designing high-performance liquid phase sensors by using pseudo-LFE devices.

It is clear that the incompatibility system in Fragaria is gametophytic, however, the genetic mechanism behind this remains elusive. Eleven second-generation lines of Fragaria viridis with different compatibility were obtained by manual self-pollination, which can be displayed directly by the level of fruit-set rate. We sequenced two second-generation selfing lines with large differences in fruit-set rate: Ls-S2-53 as a self-incompatible sequencing sample, and Ls-S2-76 as a strong self-compatible sequencing sample. Fragaria vesca was used as a completely self-compatible reference sample, and the genome-wide variations were identified and subsequently annotated. The distribution of polymorphisms is similar on each chromosome between the two sequencing samples, however, the distribution regions and the number of homozygous variations are inconsistent. Expression pattern analysis showed that six candidate genes were significantly associated with self-incompatibility. Using F. vesca as a reference, we focused our attention on the gene FIP2-like (FH protein interacting protein), associated with actin cytoskeleton formation, as the resulting proteins in Ls-S2-53 and Ls-S2-76 have each lost a number of different amino acids. Suppression of FIP2-like to some extent inhibits germination of pollen grains and growth of pollen tubes by reducing F-actin of the pollen tube tips. Our results suggest that the differential distribution of homozygous variations affects F. viridis fruit-set rate and that the fully encoded FIP2-like can function normally to promote F-actin formation, while the new FIP2-like proteins with shortened amino acid sequences have influenced the (in)compatibility of two selfing lines of F. viridis.

In this work, we propose a principal component analysis and system identification–based failure assessment approach for evaluating the partial actuator debonding failures in smart composite structures. Actuator debonding failure changes the structural dynamic characteristics and reduces the actuation capabilities as well in smart composite structures. First, the modeling of actuator debonding in smart composite laminate is developed using the finite element method, which incorporates the improved layerwise theory and higher-order electric potential field for the electromechanical coupling. Second, the structural responses obtained from the developed modeling are fed into the system identification to identify the system parameters of both healthy and damaged systems. Third, the achieved system parameters are further used for the statistical analysis by principal component analysis to extract the failure-sensitive features. Finally, a numerical example is studied using a 16-layer cross-ply laminate ([0/90]4s) as the substrate with various actuator debonding sizes. The results show that the actuator debonding failures can be well assessed, and the failure intensity and location can also be evaluated using the proposed approach.