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Zinc oxide nanoparticles (nano-ZnO) have diverse applications in numerous biomedical processes. The present study explored the effects of these nanoparticles on antioxidation, inflammation, tight junction integrity, and apoptosis in heat-stressed bovine intestinal epithelial cells (BIECs). Primary BIECs that were isolated and cultured from calves either were subjected to heat stress alone (42°C for 6 h) or were simultaneously heat-stressed and treated with nano-ZnO (0.8 μg/mL). Cell viability, apoptosis, and expression of genes involved in antioxidation (Nrf2, HO-1, SOD1, and GCLM), inflammation-related genes (TLR4, NF-κB, TNF-α, IL-6, IL-8, and IL-10), intestinal barrier genes (Claudin, Occludin, and ZO-1), and apoptosis-related genes (Cyt-c, Caspase-3, and Caspase-9) were assessed to evaluate the effect of nano-ZnO on heat-stressed BIECs. The nanoparticles significantly increased cell viability and decreased the rate of apoptosis of BIECs induced by heat stress. In addition, nano-ZnO promoted the expression of antioxidant-related genes HO-1 and GCLM and anti-inflammatory cytokine gene IL-10, and inhibited the pro-inflammatory cytokine-related genes IL-6 and IL-8. The nanoparticles also enhanced expression of the Claudin and ZO-1 genes, and decreased expression of the apoptosis-related genes Cyt-c and Caspase-3. These results reveal that nano-ZnO improve the antioxidant and immune capacity of BIECs and mitigate apoptosis of intestinal epithelial cells induced by heat stress. Thus, nano-ZnO have potential for detrimental the adverse effects of heat stress in dairy cows. [ABSTRACT FROM AUTHOR]

Ultrasonic vibration–assisted core drilling has achieved some beneficial results in carbon fiber–reinforced plastics (CFRP) hole machining. Among them, longitudinal-torsional ultrasonic-assisted core drilling (LTUACD) shows more significant advantages in decreasing cutting force and reducing delamination defects and other aspects compared to longitudinal ultrasonic-assisted core drilling (LUACD). However, the reduction mechanism of cutting force and delamination defects in LTUACD is still not clear enough. Therefore, this paper researched the machining performance of LTUACD of CFRP. Specifically, the cutting force in LTUACD of CFRP is analyzed based on hertz contact theory and indentation depth theory. Then, a series of experiments were conducted to verify the analysis. And delamination suppression mechanism was discussed from the aspects of surface morphology of hole wall, exit morphology of hole, and bottom surface morphology of blind hole. The results show that the cutting force is significantly reduced in LTUACD compared to conventional core drilling (CCD) and LUACD due to the additional torsional vibration of tool, which changes the contact state between abrasive grain and material. Therefore, the exit delamination is further suppressed. In addition, the adhesion phenomenon of chips on the tool is also reduced, which enhances the tool cutting ability to obtain even fiber fracture surfaces and greatly improves hole quality. [ABSTRACT FROM AUTHOR]

Carbon fiber–reinforced polymer (CFRP) has the characteristics of high brittleness and high hardness, which easily causes delamination damage and burr damage, resulting in low hole-making efficiency, and the application of cutting fluid in the process will lead to the decrease of mechanical properties of the material. In order to improve the surface quality and processing efficiency of CFRP, an ultrasonic-assisted dry helical milling technology is proposed. Taking tool rotation speed, feed rate, pitch, and ultrasonic amplitude as optimization variables and taking minimum delamination damage, burr damage, and maximum material removal rate as objective functions, multi-objective optimization models are established through experiments and genetic algorithm, and Pareto optimal solution sets are obtained. The results show that the influence weights are in the order of pitch, tool rotation speed, ultrasonic amplitude, and feed rate for the analysis of variance of delamination damage, accounting for 38.7%, 24.9%, 20.9%, and 15.5%, respectively. The maximum weight of pitch is 29.7%, and the minimum weight of ultrasonic amplitude is 18.1%, in the analysis of variance of burr damage. Finally, multi-objective optimization models are verified by experiments, and it is concluded that the established optimization models can provide multiple parameter optimization schemes for different engineering applications with high accuracy. [ABSTRACT FROM AUTHOR]

Cow dung waste has caused severe environmental pollution and public health issues in China. In this study, the cow dung residues were used as a cheap renewable fiber to modify asphalt binder, providing a new solution for the proper disposal of cow dung waste. Three cow dung fibers with two lengths were prepared using different treatments, including original cow dung fiber (CDF), surface treatments of cow dung fiber (STCDF) and alkali treatments of cow dung fiber (ATCDF). The physicochemical properties of CDF, STCDF and ATCDF were analyzed by scanning electron microscope (SEM) and thermogravimetry (TG). The viscidity, rheological properties and fatigue characteristics of CDF modified asphalt binders (CDFMA) were evaluated using Brookfield viscometer and dynamic shear rheometer. The results showed that the rough surfaces of STCDF and ATCDF improved their thermal stability. STCDF and ATCDF enhanced the resistance to permanent deformation under high temperature conditions of modified asphalt binder. STCDF modified asphalt binders exhibited the best viscosity and rheological performance. The increase of fiber length was positively correlated with the high temperature deformation resistance of CDFMA. CDF, STCDF and ATCDF inhibited fatigue cracking of modified asphalt binders compared to base asphalt binders. ATCDF modified asphalt binders exhibited higher fatigue life and smaller crack under the same cyclic loading. The increase in fiber length had a slight improvement on the fatigue resistance of modified asphalt binders. [ABSTRACT FROM AUTHOR]

In this paper, we study the following p-Kirchhoff-type elliptic problem: - M (∫ Ω | ∇ u | p d x) Δ p u = λ f (x) u γ + g (x) u q - 1 | x | s in Ω , u = 0 on ∂ Ω , where λ and γ are positive constants. Under some appropriate conditions on the singularity and the coefficients, the existence and multiplicity of positive solutions to this problem are obtained. Our approaches are based on the variational method and perturbation method. [ABSTRACT FROM AUTHOR]

In the drilling process of difficult-to-cut materials, conventional drilling has resulted in various problems such as high drilling temperature and poor machining quality. Low-frequency vibration-assisted drilling has great potential in overcoming these problems since broken chips are generated. In this paper, a low-frequency vibration-assisted drilling device is developed by using a novel ring flexure hinge as the elastic recovery mechanism. Firstly, based on the theory of elastic mechanics and mechanical vibration, the deflection of ring flexure hinge is designed theoretically, and the influence of its structural parameters on its deflection is analyzed. Then, the correctness of theoretical design is further verified by static and dynamic simulation and stiffness test. Finally, the vibration performance of the device is tested under no-load condition, and actual drilling test is conducted to verify the drilling performance. The results show that the device could realize the axial low-frequency vibration with constant frequency-to-rotation ratio and amplitude stepless adjustment and present good working stability under no-load and load conditions. In the actual drilling test of titanium alloy and carbon fiber–reinforced plastic (CFRP)/titanium alloy laminated structure, the device under appropriate processing parameters breaks titanium alloy chip into small pieces and reduces drilling temperature by 44% and inhibits secondary damage of CFRP. It provides the reference and guidance for the development of LFVAD device in presented work. [ABSTRACT FROM AUTHOR]

In this paper, we study the Neumann boundary value problem to a quasilinear elliptic equation with the critical Sobolev exponent and critical Hardy–Sobolev exponent, and prove the existence of nontrivial nonnegative solution by means of variational method. [ABSTRACT FROM AUTHOR]

Objective: Early recognition of children with severe Hand-Foot-and-Mouth disease (HFMD) is especially important, as severe cases are associated with poor prognosis. To accomplish this, authors designed a quantitative assessment tool to build a nomogram to assist in clinical diagnosis.Methods: A total of 2332 HFMD patients were enrolled in this study; 1750 cases in the mild group and 582 cases in the severe group. Analysis of all of the data was performed using R software version 3.4.3. Multivariate logistic regression was utilized to screen predictors to construct a nomogram model. Finally, predictive performance of the model was evaluated using a receiver operating characteristic (ROC) curve and classifier calibration plot.Results: A nomogram was constructed with five variables: age, peak temperature, fever duration, pathogen, and vomiting. For the nomogram, the area under the curve was 0.87, and the model prediction accuracy rate was 85.2%. Depending upon the comparison of the area under the ROC curve, the nomogram model was superior to the traditional pediatric clinical illness score (PCIS). With the help of the Hosmer-Lemeshow test and resampling model calibration curve, the fitting performance of the nomogram was stable.Conclusions: With advantages such as simplicity, intuitiveness, and practicality, the nomogram (including age, peak temperature, fever duration, pathogen, and vomiting) is capable of predicting severe HFMD and has certain auxiliary value in clinical applications. [ABSTRACT FROM AUTHOR]

The main purpose of this paper is to establish the existence and multiplicity of nontrivial solutions for a quasilinear Neumann problem with critical exponent. It is shown, by the methods of the Lions concentration-compactness principle and the mountain pass lemma, that under certain conditions, the existence of nontrivial solutions are obtained. [ABSTRACT FROM AUTHOR]