Molecular Dynamics Simulation of the Thermomechanical and Tribological Properties of Graphene-Reinforced Natural Rubber Nanocomposites

The thermomechanical and tribological properties of graphene (GNS)-reinforced NR were investigated using molecular dynamics (MD) simulations. The amorphous molecular dynamics models of two nanocomposites, i.e., natural rubber (pure NR) and graphene/natural rubber (GNS/NR), were established. In addition, the thermodynamic properties of the two materials, before and after the incorporation of graphene into the natural rubber matrix, were investigated through analytical comparison. The results showed that after the graphene was added to the rubber matrix as a reinforcing material, the elastic modulus and shear modulus were increased by 110% and 94.8%, respectively, the tensile property was increased by 178%, the overall thermal conductivity of the composite system was increased by 59%, the glass transition temperature increased from 223 K to 236 K, and the rigidity of the material matrix was significantly improved. The inherent interactions and wear mechanisms of the polymer nanocomposites were discussed at the atomic scale by analyzing the changes in temperature, atomic velocity, relative atomic concentration, and radial distribution functions at the friction interface in the thickness direction

Temperature Dependence of Rubber Hyper-Elasticity Based on Different Constitutive Models and Their Prediction Ability

Based on the electronic universal testing machine with a temperature chamber, this paper investigated the temperature and filler effects on the hyper-elastic behavior of reinforced rubbers and revealed the regulation of the stress and strain of the natural rubber and filled rubber with temperature. The experimental results showed that the hyper-elastic behavior of the filled rubber was temperature-dependent in a wide range. Comparing the adaptability of different models to the stress–strain variation with temperature, the Yeoh model was proven to reasonably characterize the experimental data at different temperatures. Based on the Yeoh model, an explicit temperature-dependent constitutive model was developed to describe the stress–strain response of the filled rubber in a relatively large temperature range. The prediction data of this proposed constitutive model fit well with the test data of the mechanical experiments, indicating that the model is suitable to characterize the large deformation behavior of filled rubbers at different temperatures to a certain degree. The proposed model can be used to obtain the material parameters and has been successfully applied to finite element analysis (FEA), suggesting a high application value. Notably, the model has a simple form and can be conveniently applied in related performance tests of actual production or finite element analysis

Association of shift-work, daytime napping, and nighttime sleep with cancer incidence and cancer-caused mortality in Dongfeng-tongji cohort study

<p><b>Background:</b> Few studies investigated the combined effects of night-shift work, daytime napping, and nighttime sleep on cancer incidence and mortality.</p> <p><b>Methods:</b> A total of 25,377 participants were included in this study. Information on sleep habits, cancer incidences, and mortalities were collected. Cox proportional hazards models were used to calculate the adjusted hazard ratios and 95% confidence intervals (HRs, 95%CIs).</p> <p><b>Results:</b> Male subjects experienced ≥20 years of night-shift work, or without daytime napping had an increased risk of cancer, when compared with males who did not have night-shift work or napped for 1–30 min [HR (95%CI) = 1.27 (1.01–1.59) and 2.03 (1.01–4.13), respectively]. Nighttime sleep for ≥10 h was associated with a separate 40% and 59% increased risk of cancer [HR (95%CI) = 1.40 (1.04–1.88)] and cancer-caused mortality [HR (95%CI) = 1.59 (1.01–2.49)] than sleep for 7–8 h/night. Combined effects of three sleep habits were further identified. Male participants with at least two above risk sleep habits had a 43% increased risk of cancer [HR (95%CI) = 1.43 (1.07–2.01)] and a 2.07-fold increased cancer-caused mortality [HR (95%CI) = 2.07 (1.25–3.29)] than those who did not have any above risk sleep habits. However, no significant associations were observed among women.</p> <p><b>Conclusions:</b> Long night-shift work history, without daytime napping, and long nighttime sleep duration were independently and jointly associated with higher cancer incidence among males.KEY MESSAGES</p><p>Night-shift work of ≥20 years, without napping, and nighttime sleep of ≥10 h were associated with increased cancer incidence.</p><p>Nighttime sleep ≥10 h was associated with a 2.07-fold increased cancer-caused mortality among males.</p><p>Combined effects of night-shift work ≥20 years, without napping, and nighttime sleep ≥10 h on increasing cancer incidence were existed among males.</p><p></p> <p>Night-shift work of ≥20 years, without napping, and nighttime sleep of ≥10 h were associated with increased cancer incidence.</p> <p>Nighttime sleep ≥10 h was associated with a 2.07-fold increased cancer-caused mortality among males.</p> <p>Combined effects of night-shift work ≥20 years, without napping, and nighttime sleep ≥10 h on increasing cancer incidence were existed among males.</p

Guidelines for the use and interpretation of assays for monitoring autophagy (4th edition)

In 2008, we published the first set of guidelines for standardizing research in autophagy. Since then, this topic has received increasing attention, and many scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Thus, it is important to formulate on a regular basis updated guidelines for monitoring autophagy in different organisms. Despite numerous reviews, there continues to be confusion regarding acceptable methods to evaluate autophagy, especially in multicellular eukaryotes. Here, we present a set of guidelines for investigators to select and interpret methods to examine autophagy and related processes, and for reviewers to provide realistic and reasonable critiques of reports that are focused on these processes. These guidelines are not meant to be a dogmatic set of rules, because the appropriateness of any assay largely depends on the question being asked and the system being used. Moreover, no individual assay is perfect for every situation, calling for the use of multiple techniques to properly monitor autophagy in each experimental setting. Finally, several core components of the autophagy machinery have been implicated in distinct autophagic processes (canonical and noncanonical autophagy), implying that genetic approaches to block autophagy should rely on targeting two or more autophagy-related genes that ideally participate in distinct steps of the pathway. Along similar lines, because multiple proteins involved in autophagy also regulate other cellular pathways including apoptosis, not all of them can be used as a specific marker for bona fide autophagic responses. Here, we critically discuss current methods of assessing autophagy and the information they can, or cannot, provide. Our ultimate goal is to encourage intellectual and technical innovation in the field