Multiscale Analogue Modelling of Clinching Process to Investigate Thickness Tolerance and Tool Misalignment

NEED—The effect of dimensional variability of sheet thickness (tolerance) and tool misalignment is poorly understood for the clinching process. Finite element analysis (FEA) is valuable but requires a lot of and is difficult to verify in this situation due to the asymmetrical geometry and nonlinear plasticity. OBJECTIVE—The objective of this work was to determine the effect of thickness tolerance, tool misalignment and sheet placement (top vs. bottom) in the clinching process, by use of analogue modelling with plasticine. METHOD—Experiments used a scaled-up punch and die, with plasticine as the analogue. Thickness tolerances were represented by sheet thicknesses of 11 and 7 mm, 12 and 8 mm, 8 and 12 mm and 13 and 9 mm for upper and lower sheets, respectively. Two types of lubricant were tested between sheets: glycerine and silicone oil. Angular variability was also introduced. Measured parameters were interlock (also called undercut) and neck thickness. Analogue results for deformation were compared with microscopy of metal clinching. FINDINGS—The results reveal that the multiscale analogue model is an efficient tool for studying the effect of dimensional deviation on a clinch joint. Thickness tolerance showed a critical relationship with interlock, namely a reduction to about half that of the nominal, for both maximum and least material conditions. Increased angular misalignment also reduced the interlock. Compared with glycerine, silicone oil tests showed reduced interlock, possibly the result of a lower coefficient of friction. ORIGINALITY—This work demonstrates the usefulness of analogue modelling for exploring process variability in clinching. The results also show that significant effects for sheet placement are ductility, lubricant (friction), thickness of samples and tool misalignment.     

Human Milk Metabolomics Are Related to Maternal Adiposity,Infant Growth Rate and Allergies: The Chinese Human Milk Project

The metabolomic profiles of Chinese human milk have been poorly documented. The objective of the study was to explore associations between human milk metabotypes, maternal adiposity, infant growth patterns, and risk of allergies. Two hundred mother–infant dyads from seven cities were randomly selected from the Chinese Human Milk Project (CHMP). Untargeted human milk metabolomic profiles were determined using HPLC-MS/MS. Two human milk metabotypes were identified using principal component analysis. Principal component (PC) 1 was characterized by high linoleic acid metabolites with low purine nucleosides and metabolites of glutamate and glutathione metabolism. PC 2 was characterized by high glycerophospholipids and sphingomyelins content. Higher PC1 scores were associated with slower infant growth rate and higher ambient temperature (p < 0.05). Higher PC 2 scores were related to higher maternal BMI and increased risk of infant allergies (p < 0.05). Future work is needed to understand the biologic mechanisms of these human milk metabotypes.     

A First-Principles Study on the Hydration Behavior of (MgO)n Clusters and the Effect Mechanism of Anti-Hydration Agents

Magnesia-based refractory is widely used in high-temperature industries; its easy hydration is, however, a key concern in refractory processing. Understanding the hydration mechanism of MgO will help in solving its hydration problem. Herein, the hydration behavior of (MgO)_n (n = 1–6) at the molecular level and the effect mechanisms of several anti-hydration agents on the hydration of (MgO)₄ were investigated with first-principles calculations. The results indicated that the following: (1) The smaller the (MgO)_n cluster size, the more favorable the hydration of MgO and the tendency to convert into Mg(OH)₂ crystal; (2) Anti-hydration agents can coordinate with the unsaturated Mg atom of (MgO)₄ to form a bond, increasing the coordination number of Mg, thus reducing its activity when reacting with H₂O; (3) The greater the number of −COOH groups and the longer the chain length in the anti-hydration agents, the better its effect of inhibiting the hydration of MgO. These findings could enhance the understanding of the mechanism of hydration of MgO and provide theoretical guidance for the design of novel anti-hydration agents.     

Development and Optimization of Broadband Acoustic Metamaterial Absorber Based on Parallel–Connection Square Helmholtz Resonators

An acoustic metamaterial absorber of parallel–connection square Helmholtz resonators is proposed in this study, and its sound absorption coefficients are optimized to reduce the noise for the given conditions in the factory. A two–dimensional equivalent simulation model is built to obtain the initial value of parameters and a three–dimensional finite element model is constructed to simulate the sound absorption performance of the metamaterial cell, which aims to improve the research efficiency. The optimal parameters of metamaterial cells are obtained through the particle swarm optimization algorithm, and its effectiveness and accuracy are validated through preparing the experimental sample using 3D printing and measuring the sound absorption coefficient by the standing wave tube detection. The consistency between the experimental data and simulation data verifies feasibility of the proposed optimization method and usefulness of the developed acoustic metamaterial absorber, and the desired sound absorption performances for given conditions are achieved. The experimental results prove that parallel–connection square Helmholtz resonators can achieve an adjustable frequency spectrum for the low frequency noise control by parameter optimization, which is propitious to promote its application in reducing the noise in the factory.     

Protective Effects of Polydatin from Grapes and Reynoutria japonica Houtt. on Damaged Macrophages Treated with Acetaminophen

The unregulated use of acetaminophen (APAP), an antipyretic and analgesic drug, harms hepatocytes and kidney cells, leading to liver failure and acute kidney injury. Herein, we investigate whether APAP damages macrophages in the immune system by observing its effects on macrophage proliferation and apoptosis. Using proteomics, we analyzed the effects of APAP on macrophage protein expression profiles and evaluated whether polydatin, the active ingredient in grapes and wine, can repair the damaged cells. The results showed that APAP alters the morphology and physiological processes of macrophages, inhibits macrophage proliferation, and promotes apoptosis. We observed 528 differentially expressed proteins when 500 µg/mL APAP was administered to the cells. These proteins are involved in biological processes including cell division, apoptosis, and acute phase response. Overall, our findings demonstrate that APAP harms the immune system by damaging macrophages and that polydatin can repair this damage.     

微动刺激幅值对骨组织与钛珠涂层界面的骨生长与微损伤的影响

目的 通过微动力学刺激改善人工关节生物固定界面的性能。 方法 以活性大鼠骨组织与非活性钛珠涂层的结合试样作为研究对象,利用自制的微动力学刺激试验装置,探究不同切向微动幅值的力学刺激对固定界面骨组织生长促进作用及骨组织微损伤的影响,揭示微动刺激下骨组织在钛珠涂层表面的促进生长与微损伤机制。 结果 微动幅为 40 μm 力学刺激组骨组织与钛珠涂层间的界面结合力最大,切向摩擦力-位移曲线由椭圆形转变为直线形,结合界面处于粘着区,不易产生松动,骨组织结构最完整,钛珠涂层表面黏附生长的组织细胞数量最多,分布范围最广。 随着微动幅值的增加,微动刺激对骨生长的促进作用减弱,骨组织与钛珠涂层界面间结合强度逐渐降低,内部空腔区域增多,组织细胞的数量及增殖活性也有不同程度的降低。 结论 不同幅值微动刺激对于组织的生长促进与微损伤同时存在,最优的微动幅值为 40 μm。     

Evaluation of the Immunogenicity in Mice Orally Immunized with Recombinant Lactobacillus casei Expressing Porcine Epidemic Diarrhea Virus S1 Protein

Porcine epidemic diarrhea (PED), characterized by diarrhea, vomiting, and dehydration, is an acute enteric infectious disease of pigs. The disease is caused by porcine epidemic diarrhea virus (PEDV), which infects the intestinal mucosal surface. Therefore, mucosal immunization through the oral route is an effective method of immunization. Lactic acid bacteria, which are acid resistant and bile-salt resistant and improve mucosal immunity, are ideal carriers for oral vaccines. The S1 glycoprotein of PEDV mediates binding of the virus with cell receptors and induces neutralizing antibodies against the virus. Therefore, we reversely screened the recombinant strain pPG-SD-S1/Δupp ATCC 393 expressing PEDV S1 glycoprotein by Lactobacillus casei deficient in upp genotype (Δupp ATCC 393). Mice were orally immunized three times with the recombinant bacteria that had been identified for expression, and the changes of anti-PEDV IgG and secreted immunoglobulin A levels were observed over 70 days. The results indicated that the antibody levels notably increased after oral administration of recombinant bacteria. The detection of extracellular cytokines on the 42nd day after immunization indicated high levels of humoral and cellular immune responses in mice. The above results demonstrate that pPG-SD-S1/Δupp ATCC 393 has great potential as an oral vaccine against PEDV.     

Resistance of Xanthomonas oryzae pv. oryzae to Lytic Phage X2 by Spontaneous Mutation of Lipopolysaccharide Synthesis-Related Glycosyltransferase

Phage therapy is a promising biocontrol management on plant diseases caused by bacterial pathogens due to its specificity, efficiency and environmental friendliness. The emergence of natural phage-resistant bacteria hinders the application of phage therapy. Xanthomonas oryzae pv. oryzae (Xoo) is the causal agent of the devastating bacterial leaf blight disease of rice. Here, we obtained a spontaneous mutant C2R of an Xoo strain C2 showing strong resistance to the lytic phage X2. Analysis of the C2R genome found that the CDS2289 gene encoding glycosyltransferase acquired a frameshift mutation at the 180th nucleotide site, which also leads to a premature stop mutation at the 142nd amino acid. This mutation confers the inhibition of phage adsorption through the changes in lipopolysaccharide production and structure and bacterial surface morphology. Interestingly, glycosyltransferase-deficient C2R and an insertional mutant k2289 also showed reduced virulence, suggesting the trade-off costs of phage resistance. In summary, this study highlights the role of glycosyltransferase in interactions among pathogenic bacteria, phages and plant hosts, which provide insights into balanced coevolution from environmental perspectives.     

Molecular Analysis of Caprine Enterovirus Circulating in China during 2016–2021: Evolutionary Significance

Here, we report the characterization of 13 novel caprine/ovine enterovirus strains isolated from different regions in China during 2016–2021. Immunoperoxidase monolayer assay showed that these viral strains shared strong cross-reaction with the previously reported caprine enterovirus CEV-JL14. Alignment analysis of the complete nucleotide sequences revealed 79.2%–87.8% and 75.0%–76.7% sequence identity of these novel caprine enterovirus strains to CEV-JL14 and TB4-OEV, respectively. Phylogenetic analyses clustered these novel strains to EV-G based on the amino acid sequences of P1 and 2C+3CD. Moreover, phylogenetic analysis of these caprine enterovirus strains identified three new EV-G types using VP1 sequences. These results demonstrate the genetic variations and the evolution of caprine enterovirus.