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Enterobacter cloacae is a troublesome pathogen causing refractory infections of the lower respiratory tract, urethra and abdominal cavity, endocarditis, osteomyelitis, and neonatal septicemia. It is prone to developing resistance to ordinary antibiotics and has brought a serious problem to clinical treatment. An artful synergistic combination of an antibacterial natural product allicin and a newly isolated bacteriophage, named BD523, was constructed herein. This combination significantly lowered effective dosage of allicin and effectually overcame bacterial drug-resistance. We experimentally evidenced that allicin interacts with bacterial DNA in the groove region by inserting itself into the DNA double helix and, subsequently, disrupts the bacterial DNA by cleaving phosphate diester bonds of deoxynucleotides. Further, BD523 destroys the cell wall and membrane of bacteria by synthesizing lyase proteins, including holin and endolysins. Thus, the synergistic effect of the combination benefits from complementary targeting mechanisms of allicin and BD523. They cooperatively act on bacterial DNA, cell wall, and membrane to improve antibacterial efficiency and avoid drug-resistance.

Kirigami, the ancient art of paper cutting, has evolved into a design and fabrication framework to engineer multi-functional materials and structures at vastly different scales. By slit cutting with carefully designed geometries, desirable mechanical behaviors-such as accurate shape morphing, tunable auxetics, super-stretchability, buckling, and multistability-can be imparted to otherwise inflexible sheet materials. In addition, the kirigami sheet provides a versatile platform for embedding different electronic and responsive components, opening up avenues for building the next generations of metamaterials, sensors, and soft robotics. These promising potentials of kirigami-based engineering have inspired vigorous research activities over the past few years, generating many academic publications. Therefore, this review aims to provide insights into the recent advance in this vibrant field. In particular, this paper offers the first comprehensive survey of unique mechanical properties induced by kirigami cutting, their underlying physical principles, and their corresponding applications. The synergies between design methodologies, mechanics modeling, advanced fabrication, and material science will continue to mature this promising discipline.

Origami — the ancient art of paper folding — has been widely adopted as a design and fabrication framework for many engineering applications, including multi-functional structures, deployable spacecraft, and architected materials. These applications typically involve complex and dynamic deformations in the origami facets, necessitating high-fidelity models to better simulate folding-induced mechanics and dynamics. This paper presents the formulation and validation of such a new model based on the Absolute Nodal Coordinate Formulation (ANCF), which exploits the tessellated nature of origami and describes it as an assembly of flexible panels rotating around springy creases. To estimate the crease folding, we mathematically formulate a “torsional spring connector” in the framework of ANCF and apply it to the crease nodes, where the facets meshed by ANCF plate elements are interconnected. We simulate the dynamic folding of a Miura-ori unit cell and compare the results with commercial finite element software (ABAQUS) to validate the modeling accuracy. The ANCF model can converge using significantly fewer elements than ABAQUS without sacrificing accuracy. Therefore, this high-fidelity model can help deepen our knowledge of folding-induced mechanics and dynamics, broadening the appeals of origami in science and engineering.

Glycosidic bond of C-glycosides is difficult to be broken due to its chemical stability. Screening specific microbe from microbiota is a practical way to deglycosylate these compounds. In this study, a new strain W974-1 which is capable of cleaving C-glycosidic bonds was isolated from human gut microbiota by spread plate method. It deglycosylates flavonoid 8-C-glycosides such as orientin and vitexin to their aglycones with the enzymes secreted outside the bacterial cells. This strain was identified as Enterococcus avium by 16S rDNA sequencing, physiological and biochemical characterization.

The mechanism of berberine hydrochloride (BBH) inhibiting the biofilm formation of Hafnia alvei was investigated in this study. The antibiofilm potential of BBH was evaluated by confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM) as well as crystal violet staining. The quorum-sensing (QS) inhibition was revealed by determination of QS-related genes expression and related signal molecules production using real-time quantitative PCR (RT-qPCR) and high performance liquid chromatography (HPLC). The binding of BBH to receptor proteins was simulated by molecular docking and molecular dynamics simulations. It was found that BBH at sub-minimum inhibitory concentrations (sub-MICs) significantly reduced the biofilm formation of H. alvei in a dose dependent manner. BBH inhibited the bacterial swimming motility, decreased the transcription of halI and halR genes, and reduced the production of signal molecule C14-HSL. It bound to HalR protein mainly through Van der Waals force and electrostatic interaction force. Based on these results, it was concluded that BBH inhibits the biofilm formation of H. alvei and the mechanism is related to its interference with QS through down-regulating the expression of halI and halR genes.

Traditionally, origami has been categorized into two groups according to their kinematics design: rigid and non-rigid origami. However, such categorization can be superficial, and rigid origami can obtain new mechanical properties by intentionally relaxing the rigid-folding kinematics. Based on numerical simulations using the bar-hinge approach and experiments, this study examines the multi-stability of a stacked Miura-origami cellular structure with different levels of facet compliance. The simulation and experiment results show that a unit cell in such cellular solid exhibits only two stable states if it follows the rigid origami kinematics; however, two more stable states are reachable if the origami facets become sufficiently compliant. Moreover, the switch between two certain stable states shows an asymmetric energy barrier, meaning that the unit cell follows fundamentally different deformation paths when it extends from one state to another compared to the opposite compression switch. As a result, the reaction force required for extending this unit cell between these two states can be higher than the compression switch. Such asymmetric multi-stability can be fine-tuned by tailoring the underlying origami design, and it can be extended into cellular solids with carefully placed voids. By showing the benefits of exploiting facet compliance, this study could foster multi-functional structures and material systems that traditional rigid origami cannot create., 28 pages with 8 figures

Random fatigue is inherently multi-axial due to the complex stress state in real vibrating structures. This paper investigates the role of Stress Modal Analysis (SMA) in multi-axial random fatigue. Predicting hotspots of multi-axial random fatigue by Stress Mode Shapes (SMSs) was theoretically demonstrated. An improved approach was proposed to exploit SMSs in random fatigue with a multi-axial criterion. First, SMA is conducted to locate the multi-axial fatigue hotspots in a vibrating structure. Second, the frequency-domain approach for random fatigue is performed at the identified hotspots. The capability of SMSs in locating multi-axial fatigue hotspots was verified by numerical investigation. The finite element (FE) model of an L-shaped thin-walled structure containing geometry changes was constructed for case study. Local regions were identified as hotspots by SMSs information. Then, random response and multi-axial fatigue damage of the whole structure were evaluated for verification. Damage map indicates that the critical positions predicted by SMSs have good accuracy. Results show the improved approach with SMA can ensure both accuracy and efficiency for multi-axial random fatigue.

Ethnopharmacological relevance Eighteen Incompatible Medicaments (EIM) belongs to the category of incompatibility of Traditional Chinese medicine (TCM). This theory forbids concomitant using any one of the eighteen herbal pairs such as Radix Glycyrrhizae (RG)-Radix Euphorbiae Pekinensis (REP), Radix Aconiti-Bulbus Fritiliariae Cirrhosae, and Radix et Rhizoma Veratri Nigri-Radix Ginseng. Concomitant using RG and REP could result in more serious adverse effects on major organs such as kidney, heart, and liver. Aim of the study To investigate the effects of RG-REP decoctions on gut microbiota and short-chain fatty acids (SCFAs) for the purpose of elucidating the mechanism of RG-REP incompatibility. Materials and methods Six groups of male SD rats were intragastrically administrated with distilled water, RG decoction, REP decoction, 1:1 RG-REP decoction, 2:1 RG-REP decoction and 3:1 RG-REP decoction, respectively, twice daily for 30 consecutive days, and the feces of each rat was separately sampled for gut microbiota analysis and SCFAs assay. 16S rDNA sequencing was employed to comparatively investigate the structure and abundance of intestinal bacteria in rat feces. Gas chromatography (GC) was used to quantitatively determine the contents of SCFAs in rat feces and in vitro samples. The correlation between bacteria and the production of SCFAs was analyzed by Spearman correlation analysis. An in vitro model of human intestinal bacteria was also constructed to simulate and validate the in vivo experiment. Results The contents of butyric acid in both rat feces and in vitro samples decreased in RG-REP groups. The general structure of gut microbiota in RG-REP groups was not significantly different from that in control group. However, RG alone increased the abundance of Lactobacillus while this effect was counteracted by concomitant using with REP. REP alone decreased the abundance of two interrelated species, Akkermansia and Butyricimonas, and this effect was strengthened by concomitant using REP with RG in the ratio of 1:1. In comparison with REP alone, RG-REP combination also significantly increased the abundance of Streptococcus and Prevotella. Conclusion The incompatibility of RG-REP combination is associated with its negative effect against probiotic bacteria and positive effect on conditional pathogenic bacteria as well as its inhibition on butyric acid production.

The air-lubricated six-axis force/moment sensor, a novel sensor developed using the gas lubrication principle, could avoid the coupling phenomenon and increase its precision to 0.2% full scale. During the sensor development, the stability of the nozzle-floating plate mechanism is a key issue, which is mainly caused by the “hammer phenomenon” that is affected by the size of the nozzle’s orifice. In this study, an air hammer stability criterion for the sensor was proposed and the design of the nozzle was optimized to avoid the air hammer phenomenon. The stable characteristics of the optimized nozzle were further verified with experiments through comparison with characteristics of the normal nozzle. In conclusion, the hammer instability phenomenon was averted through the optimal design of the nozzle and the precision of the air-lubricated six-axis sensor was improved, which can be applied in calibrating flexible tactile sensors with high-precision requirement.

Origami-inspired structures and material systems have been used in many engineering applications because of their unique kinematic and mechanical properties induced by folding. However, accurately modeling and analyzing origami folding and the associated mechanical properties are challenging, especially when large deformation and dynamic responses need to be considered. In this paper, we formulate a high-fidelity model — based on the iso-parametric Absolute Nodal Coordinate Formulation (ANCF) — for simulating the dynamic folding behaviors of origami involving large deformation. The center piece of this new model is the characterization of crease deformation. To this end, we model the crease using rotational spring at the nodes. The corresponding folding angle is calculated based on the local surface normal vectors. Compared to the currently popular analytical methods for analyzing origami, such as the rigid-facet and equivalent bar-hinge approach, this new model is more accurate in that it can describe the large crease and facet deformation without imposing many assumptions. Meanwhile, the ANCF based origami model can be more efficient computationally compared to the traditional finite element simulations. Therefore, this new model can lay down the foundation for high-fidelity origami analysis and design that involve mechanics and dynamics.

This paper describes the design, working principle, as well as calibration of an air-floating six-axis force measurement platform, where the floating plate and nozzles were connected without contact, preventing inter-dimensional coupling and increasing precision significantly. The measurement repeatability error of the force size in the platform is less than 0.2% full scale (FS), which is significantly better than the precision of 1% FS in the six-axis force sensors on the current market. We overcame the difficulties of weight loading device in high-precision calibration by proposing a self-calibration method based on the floating plate gravity and met the calibration precision requirement of 0.02% FS. This study has general implications for the development and calibration of high-precision multi-axis force sensors. In particular, the air-floating six-axis force measurement platform could be applied to the calibration of some special sensors such as flexible tactile sensors and may be used as a micro-nano mechanical assembly platform for real-time assembly force testing.

In this paper, air hammer instability of nozzle-floating plate institution in gas lubricated force sensor were studied. Through establishment of the theoretical model for the analysis of the nozzle-floating plate institution stability, combined with air hammer stability judgment theorems, we had some simulation research on the radius of the nozzle, the radius of the pressure chamber, pressure chamber depth, orifice radius and the relationship between air supply pressure and bearing capacity, in order to explore the instability mechanism of nozzle-floating plate institution. For conducting experimental observations for the stability of two groups nozzle-floating plate institution, which have typical structural parameters conducted experimental observations. We set up a special experimental device, verify the correctness of the theoretical study and simulation results. This paper shows that in the nozzle-floating plate institution, increasing the nozzle diameter, reduced pressure chamber radius, reducing the depth of the pressure chamber and increase the supply orifice radius, and other measures is conducive to system stability. Results of this study have important implications for research and design of gas lubricated force sensor.