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Bionic and gradient designs offer promising applications in honeycomb structures. The intersection unit of the beetle elytra is extracted as to enhance regular hexagonal honeycomb (RHH), and several bionic honeycombs are proposed. Finite element (FE) modeling approach is verified through formulae and experiments. Curves of force and displacement of bionic honeycombs present two prominent stages under medium- and low-speed impacts in plateau stage, and several bionic honeycombs exhibit a zero or negative Poisson's ratio. The specific energy absorption (SEA) of INT_6, whose crashworthiness is best in bionic honeycombs. A gradient design of INT_6 is implemented to further increase its crashworthiness. Multi-objective optimization design (MOD), which aims to simultaneously increase the SEA and reduce the peak crushing force, is adopted to determine the optimal parameters of each layer of graded INT_6. The SEA of the optimized graded INT_6 increase 142%, and its peak crushing force decrease by 25.4% compared with those of the INT_6. [ABSTRACT FROM AUTHOR]

• Novel horsetail bio-honeycombs (HBHs) are proposed based on horsetail stems. • A theoretical model of HBHs is established to predict their average impact force. • The membrane energy for novel 5-panel and 7-panel corner elements are derived. • Three deformation modes are observed based on the thickness-length ratio of HBHs. • The HBHs exhibit significant crashworthiness advantages with same relative density. Inspired by the ingenious cross-sectional structure of horsetail stems, a group of novel horsetail bio-honeycombs (HBHs) are firstly proposed to pursuit a superior impact resistance performance. The out-of-plane impact resistance characteristics and mechanical properties of the proposed HBHs are investigated by means of test, theoretical analysis, and finite element (FE) analysis. In the process of deriving the theoretical model of HBHs, the novel 5-panel and 7-panel membrane energy dissipation corner elements are firstly proposed and reasonable theoretical solutions for them are obtained. Theoretical results suggest that the errors between numerical and theoretical results for the majority of the HBHs are within 7 %. In addition, the studies indicate that the HBHs outperform the circular honeycomb (CH) in terms of crashworthiness while ensuring that their relative densities are the same. The complex proportional assessment method is utilized to evaluate the crashworthiness of HBH _n_6_1.5 (n represents the number of ribs, 6 represents the size of the outer diameter, and 1.5 represents the ratio (ζ) of the outer diameter to the inner diameter) under the same relative density. Furthermore, results suggest that energy absorption and crushing force efficiency of HBH _16_6_1.5 are 31.31 % and 25.54 % higher than those of CH, respectively. Subsequently, the influences of geometric parameters, including the ζ and the thickness-to-cell length ratio (TL), on the impact resistance of HBH _16_6_1.5 are investigated thoroughly. The findings show that when the ζ is within 1.2–1.5, the HBHs can exert their maximum potential, in which the inner diameter of HBHs is close to its outer diameter. Also, the findings demonstrate that the HBHs will undergo three distinct deformation modes. When the TL is roughly within 0.0200–0.0267, the deformation of HBHs will be in the transition deformation mode. [Display omitted] [ABSTRACT FROM AUTHOR]

• Novel horsetails bio-honeycombs are proposed by imitating microstructures of horsetails. • The interaction effect between bionic units and regular hexagonal frame can promote EA. • The ratio of cell wall thickness to length determines deformation modes of bio-honeycombs. • A theoretical model is developed to predict the mean force of horsetails bio-honeycombs. The bionic strategy is regarded as a highly effective design approach for honeycomb structures. To improve the crushing resistance of the honeycombs, some novel bio-honeycombs are proposed by introducing the microstructure of horsetail stems into regular hexagonal honeycomb (RH) cells in this study. Two types of developed bio-honeycombs are considered, including MP type and CC type. A circular honeycomb compression test is carried out to validate the finite element (FE) model. Subsequently, FE models of bio-honeycombs are established to investigate their out-of-plane crashworthiness. The results suggest that the introduced bionic units and the RH frame component will produce a significant interaction effect, where more severe plastic deformation will be formed at their intersections and more folding lobes are formed on the cell walls. Furthermore, the effect of geometric parameters on crashworthiness of MP_6 (MP type with six ribs) bio-honeycombs is discussed. It demonstrates that the smaller cell size of bio-honeycomb is beneficial for improving the utilization efficiency of materials. The deformation modes of MP_6 bio-honeycombs are determined by the ratio of cell wall thickness to cell length (t/l), and the global bending occurs when t/l exceeds 0.0625. In addition, a theoretical model for estimating the mean crushing force of MP_6 bio-honeycombs is derived, and the error with the FE results is within 7%, confirming that the theoretical solution is in good agreement with the simulation. [Display omitted] [ABSTRACT FROM AUTHOR]

Association of lifestyle behaviors with non-alcoholic fatty liver disease and advanced fibrosis detected by transient elastography among Hispanic/Latinos adults in the U.S. Ethn Health. With great interest, we read the recent study by Kim and coworkers showing that non-alcoholic fatty liver disease (NAFLD) is associated with an increased risk of dementia in a nationwide cohort study.1 We thank them for their significant work for clinical practice, but there exist some potential pitfalls which may affect the credibility of the results. Non-alcoholic fatty liver disease does not increase dementia risk although histology data might improve risk prediction. [Extracted from the article]

• Inspired by beetle elytra intersection unit, a series of novel bionic honeycombs were designed. • Several bio-honeycombs exhibit zero or negative Poisson's ratio. • Bio-honeycombs can improve plateau stress and reduce the peak force effectively. A series of novel bionic honeycombs (bio-honeycombs) are proposed by incorporating the microstructure of the beetle elytra intersection unit into the regular hexagonal honeycomb (Hex) cell. To explore the in-plane mechanical properties and energy absorption performance of bio-honeycombs under different impact speeds, finite element (FE) models are established and verified by empirical formulas and current experiments. The results indicate that the bio-honeycombs outperform the Hex in terms of energy absorption capacity, and the nominal stress–strain curves of the bio-honeycombs show two prominent stages (stage Ⅰ and stage Ⅱ) under quasi-static and mid-impact. Bionic units also undergo two evident deformation stages: preliminary collapse and further crushing. The bending and traction of bionic units make more adjacent cells added to the collapse earlier, forming a global crushed trend, leading to an interesting phenomenon that the localized band of bio-honeycombs are always wider than that of Hex. Also, negative Poisson's ratio is observed in stage Ⅱ from several bio-honeycombs under quasi-static and mid-speed due to bionic units' bending and traction in the further crushing stage. Besides, the number and distribution of ribs have a considerable impact on the crashworthiness of bio-honeycombs. Compared with the Hex, the incorporated bionic units reduce the peak crushing force (PCF) while improving the crashworthiness of bio-honeycomb in the case of the same relative density, which provides a promising potential solution to strengthen the energy absorption performance of honeycomb structures. [ABSTRACT FROM AUTHOR]

Thermal barrier coatings (TBCs) have low thermal conductivity, effectively reducing the temperature of the metal matrix and improving thermal performance, knock resistance, and combustion performance of the piston. In this study, an off-road high-pressure common-rail diesel engine was chosen as the research object. Combined with the test results of the piston temperature field under the rated power and maximum torque conditions, a finite element simulation model of the thermal barrier coating piston was established. This model enabled the distribution characteristics and variation laws of the temperature field, stress, and deformation of the thermal barrier coating on the piston matrix to be analysed. The results show that the maximum temperature of the TBC piston is 12.2% and 13.73% lower than that of the aluminium alloy piston under the rated power and maximum torque conditions, respectively. The thermal stresses of the TBC piston at the top of the cavity were 25.9% and 26.8% lower than those of the aluminium piston, while the thermo-mechanical coupling stress of the TBC piston was slightly higher than that of the aluminium piston—1.2 MPa and 3.7 MPa in the bottom of the combustion chamber with geometric mutation, respectively. The radial thermal deformation of the TBC piston was 0.067 mm and 0.073 mm lower than that of the aluminium piston, with the radial thermo-mechanical coupling deformation also decreasing by 0.069 mm and 0.075 mm, respectively. The radial thermal deformation of the piston in the direction parallel to the pinhole axis was greater than that in the direction perpendicular to the pinhole axis; the difference in the magnitude of the change results in uneven thermal deformation of the piston. [ABSTRACT FROM AUTHOR]

Arched structures have increased in importance over the last few years due to their high efficiency in bearing loads. This paper introduces arched ribs to the classical re-entrant honeycomb (RH) as reinforced structures, and then its energy absorption is improved by simultaneously utilizing the reinforced structures and the auxetic deformation of RHs. Herein, the in-plane crashing response of reinforced RHs (RRH) under different impact velocities is investigated with finite element methods verified against the quasi-static compression experiment of 3D-printed RRH specimens. By introducing arched structures, the deformation of RHs becomes more stable and regular, and two plateau stresses are produced in the stress-strain curves of RRHs. Benefiting from the stacking deformation of RRHs and pure compression characteristic of catenary arches, the second plateau stress of all-reinforced RHs (ARH) is 3.8 times higher than the first one. Two plateau stresses of ARHs are derivated theoretically with a relative error of less than 7 %. Furthermore, a parametric study is performed to explore the effect of impact velocities, thicknesses, and the height of arched ribs on the crashing response of RRHs. The present investigation paves a new way toward strengthening the energy absorption of conventional honeycombs. [ABSTRACT FROM AUTHOR]

Abstract In this article, a non-uniform design method mapped by density-based topology optimization is proposed and applied to the classic hexagonal honeycombs. A parametric investigation is conducted to explore the effect of crucial factors on the in-plane and out-of-plane crashing behaviors and energy absorption of the non-uniform honeycomb mapped by topology optimization. Compared to classic hexagonal honeycombs, the in-plane specific energy absorption of the non-uniform honeycomb mapped by topology optimization is improved by 29.1%, and its peak stress is decreased by 16.9%. Meanwhile, the out-of-plane specific energy absorption is increased by 19.8% without a significant rise in peak stress. [ABSTRACT FROM AUTHOR]

In order to improve the crashworthiness of the crash box, the cattle horn is selected as a bionic object. A crash box filled with negative Poisson's ratio honeycomb based on horn structure was designed by extracting its excellent structural characteristics of impact resistance. The axial deformation modes and energy absorption characteristics of bionic crash box are investigated by means of finite element method, and compared with square crash box, diagonal crash box and side-to-side crash box. Under axial impact, the horn-bionic crash box shows significantly better load-carrying and energy-absorbing capacity than the square crash box and the diagonal crash box. On this basis, the thickness parameters, multi-objective optimization design and structure improvement design of horn-bionic crash box are studied successively in this work. The results show that the improved bionic crash box based on horn structure has a typical progressive shrinkage deformation mode. Its SEA reaches 29.9 kJ/kg, which is 2.5 times that of the square crash box, and its PCF is also greatly reduced from 542.4 kN to 391.1 kN. Therefore, the methods of structural improvement such as pre-deformed treatment, constraint beam adjustment and shortening the NPR core can effectively reduce the PCF of the crash box, and improve its energy absorption capacity, so as to obtain better comprehensive crashworthiness. Introducing the key characteristics of the horn structure into the design of the car crash box can effectively improve structural crashworthiness and provide new design guidance for the other energy-absorption components of vehicle. [ABSTRACT FROM AUTHOR]

Abstract: In order to utilize renewable energy to meet diverse energy requirements, a new combined cooling, heating and power (CCHP) system is proposed to produce cooling output, heating output and power output simultaneously. This proposed system combines a Brayton cycle and a transcritical CO2 refrigeration cycle with ejector-expansion device, which uses solar energy as the heat source to reduce fossil fuel consumption and alleviate environmental problems. A mathematical model is developed to simulate the new CCHP system with transcritical CO2 driven by solar energy under steady-state conditions, and the thermal efficiency and exergy efficiency are used to evaluate the system performance. The effects of several key thermodynamic parameters on the system performance are examined. The results indicate that increasing turbine inlet pressure and ejector inlet temperature could lower the efficiency of the system, and increasing turbine back pressure and turbine inlet temperature could elevate the efficiency of system. In addition, as ejector back pressure increases, the thermal efficiency of system decreases, but the exergy efficiency increases. [Copyright &y& Elsevier]

Abstract: Reaction of di-n-butyltin(IV) dichloride with 4-chlorobenzohydroxamic acid at 1:1 ratio yielded a new mixed-ligand diorganotin(IV) complex, di-n-butyl-(4-chlorobenzohydroxamato)tin(IV) chloride(DBDCT). It was fully characterized by IR, 1H, 13C, 119Sn NMR spectra and single crystal X-ray analysis. In DBDCT, the tin atom is five-coordinated in a trigonal bipyramidal geometry. DBDCT exhibited strong in vitro cytotoxic activity toward human immature granulocyte leukemia (HL-60), human salivary-gland carcinoma (SGC-7901), human henrietta carcinoma (Hela) and human urinary bladder (T24) cell lines which, in some cases, were equal to, or even higher than those of cis-dichlorodiammineplatinum(II) (cisplatin, DDP), the widely clinically used drug. The further in vivo antitumor tests of DBDCT towards the transplantation tumor models of sarcoma carcinoma (S180), hepatocellular carcinoma (H22) and Ehrlich’s ascites carcinoma (EAC) on mice were carried out via injection intraperitoneally with cisplatin as positive contrast drug. The results showed that DBDCT displayed in vivo antitumor activity against the hepatocellular carcinoma H22 and sarcoma carcinoma S180 which were close to those of cisplatin, meanwhile, the survival-extending rates at middle dose and high dose on mice Ehrlich’s ascites tumor EAC were higher than those of cisplatin, and there was a good dose-effect relationship. [Copyright &y& Elsevier]

Ring finger protein 2 (RNF2), as a well-known E3 ligase, has an oncogenic role in various cancers. The role of RNF2 in colon cancer is still unknown. The aim of this work is to determine the biological role of RNF2 in colon cancer. We first examined the expression of RNF2 and interferon regulatory factor 4 (IRF4) in colon cancer patients and colon cancer cell lines (SW480 and HCT116). Compared with normal tumor-adjacent tissues, RNF2 was up-regulated whereas IRF4 was down-regulated in the colon cancer tissues. RNF2 was also up-regulated in colon cancer cells with respect to human fetal colon epithelial cells. RNF2 overexpression enhanced the ability of proliferation, migration and invasion of SW480 cells, whereas RNF2 knockdown caused an opposite result in HCT116 cells. Furthermore, a tumor xenograft model was constructed to verify the impact of RNF2 overexpressed-SW480 cells on tumor growth. RNF2 up-regulation elevated Ki-67 proliferation index, accelerated the growth of tumor tissues, and led to severe colon tissue damage in the tumor xenograft mice. In addition, RNF2 interacted with IRF4, and repressed IRF4 protein expression. IRF4 was a substrate of RNF2, and RNF2 promoted the ubiquitination and degradation of IRF4. RNF2 overexpression increased the ability of proliferation, migration and invasion in SW480 cells by promoting the ubiquitination and degradation of IRF4. In conclusion, this work demonstrated that RNF2 promoted tumor growth in colon cancer by regulating ubiquitination and degradation of IRF4. Thus, RNF2 may be served as a potential therapeutic target for colon cancer. • RNF2 was highly expressed in colon cancer tissues and cells. • RNF2 promoted cell proliferation, migration and invasion of colon cancer cells. • RNF2 accelerated tumor growth of colon cancer in mice. • IRF4 was a substrate of RNF2, and could be ubiquitinated and degraded by RNF2. • RNF2 promoted colon cancer progression by regulating ubiquitination of IRF4. [ABSTRACT FROM AUTHOR]