Thermomechanical Peridynamic Modeling for Ductile Fracture.

In this paper, we propose a modeling method based on peridynamics for ductile fracture at high temperatures. We use a thermoelastic coupling model combining peridynamics and classical continuum mechanics to limit peridynamics calculations to the failure region of a given structure, thereby reducing computational costs. Additionally, we develop a plastic constitutive model of peridynamic bonds to capture the process of ductile fracture in the structure. Furthermore, we introduce an iterative algorithm for ductile-fracture calculations. We present several numerical examples illustrating the performance of our approach. More specifically, we simulated the fracture processes of a superalloy structure in 800 ℃ and 900 ℃ environments and compared the results with experimental data. Our comparisons show that the crack modes captured by the proposed model are similar to the experimental observations, verfying the validity of the proposed model.

Wood smoke particulate matter (WSPM2.5) induces pyroptosis through both Caspase-1/IL-1ß/IL-18 and ATP/P2Y-dependent mechanisms in human bronchial epithelial cells.

Emerging evidences have linked the air pollution particulate matters, especially the fine particulate matter PM2.5, to the disease development of chronic obstructive pulmonary disease (COPD). Our previous studies reported that biofuel PM2.5 can induce devastated damage of human bronchial epithelial cells, this study aims to further investigate the underlying molecular mechanisms how biofuel PM2.5 induces bronchial epithelial cell death and dysfunction. In this study, biofuel PM2.5 extracted from wood smoke (WSPM2.5) was used according to our previous publication. A 16-HBE cell line was used as the cell model. Results showed that: Firstly, WSPM2.5 induced significant pyroptosis in 16-HBE cells, reflected by the typical changes including elevated release of lactate dehydrogenase release (LDH) and activated activity and expression of Caspase-1/IL-1ß/IL-18 signaling pathway. Then, specific inhibitors for both Caspases (Z-VAD-FMK) and Caspase-1 (VX-765), as well as specific siRNA knockdown of IL-1ß all effectively attenuated the WSPM2.5-induced upregulation of downstream inflammatory cytokines and chemokines (IL-6, IL-8, CXCL-1, CXCL-2, etc), respectively. Notably, WSPM2.5 caused a novel increase of intracellular-to-extracellular ATP secretion, which could also contribute to the WSPM2.5-induced pyroptosis and inflammation by activating the Caspase-1/IL-1ß/IL-18 signaling pathway through possible autocrine and/or paracrine mechanisms. Antagonism of ATP (Apyrase) or specific siRNA knockdown against ATP receptors (P2Y2 and P2Y7) both significantly inhibited the WSPM2.5-induced pyroptosis and inflammation. These results add up to the current knowledge and bring up novel insights that WSPM2.5 could induce significant pyroptosis and inflammation of human bronchial epithelial cells, through both a classic NLRP3/Caspase-1/IL-1ß-dependent and a novel ATP/P2Y-dependent mechanisms.

A nomogram based on A-to-I RNA editing predicting overall survival of patients with lung squamous carcinoma.

BACKGROUND: Adenosine-to-inosine RNA editing (ATIRE) is characterized as non-mutational epigenetic reprogramming hallmark of cancer, while little is known about its predictive role in cancer survival. METHODS: To explore survival-related ATIRE events in lung squamous cell carcinoma (LUSC), ATIRE profile, gene expression data, and corresponding clinical information of LUSC patients were downloaded from the TCGA database. Patients were randomly divided into a training (n = 134) and validation cohort (n = 94). Cox proportional hazards regression followed by least absolute shrinkage and selection operator algorithm were performed to identify survival-related ATIRE sites and to generate ATIRE risk score. Then a nomogram was constructed to predict overall survival (OS) of LUSC patients. The correlation of ATIRE level and host gene expression and ATIREs' effect on transcriptome expression were analyzed. RESULTS: Seven ATIRE sites that were TMEM120B chr12:122215052A > I, HMOX2 chr16:4533713A > I, CALCOCO2 chr17:46941503A > I, LONP2 chr16:48388244A > I, ZNF440 chr19:11945758A > I, CLCC1 chr1:109474650A > I, and CHMP3 chr2:86754288A > I were identified to generate the risk score, of which high levers were significantly associated with worse OS and progression-free survival in both the training and validation sets. High risk-score was also associated with advanced T stages and worse clinical stages. The nomogram performed well in predicting OS probability of LUSC. Moreover, the editing of ATIRE sites exerted a significant association with expression of host genes and affected several cancer-related pathways. CONCLUSIONS: This is the first comprehensive study to analyze the role of ATIRE events in predicting LUSC survival. The AITRE-based model might serve as a novel tool for LUSC survival prediction.

Synthesis, structure-activity relationship and biological evaluation of novel arylpiperzines as α1A/1D-AR subselective antagonists for BPH.

A series of novel arylpiperazine derivatives as α1A/1D-adrenergic receptors (AR) subtype selective antagonists were designed, synthesized and evaluated for their antagonistic activities towards α1-ARs (α1A, α1B, and α1D). Compounds 9, 12, 13, 15, 17, 18, 21, 22, 25 and 26 exerted strong antagonistic effects on α1A and/or α1D subtypes over α1B in vitro. SAR analysis indicated that chloride at the ortho-phenyl position for compound 17 was beneficial for the highest α1A/D-AR sub-selectivity. Moreover, molecular docking study of compound 17 with the homology-modeled α1-ARs (α1A, α1B, and α1D) structures exhibited differences of key amino resides in the docking pocket which may influence the subtype selectivity. ILE 193 of α1A was validated as the key residues for binding ligand. This work provides useful information for finding more new potential drugs in clinic in treating benign prostatic hyperplasia (BPH).

Uniaxial strain-induced mechanical and electronic property modulation of silicene.

We perform first-principles calculations of mechanical and electronic properties of silicene under uniaxial strains. Poisson's ratio and the rigidity of silicene show strong chirality dependence under large uniaxial strains. The ultimate strains of silicene with uniaxial strain are smaller than those with biaxial strain. We find that uniaxial strains induce Dirac point deviation from the high-symmetry points in the Brillouin zone and semimetal-metal transitions. Therefore, no bandgap opens under the uniaxial strain. Due to its peculiar structure and variable sp (3)/sp (2) ratio of the chemical bond, the deviation directions of Dirac points from the high-symmetry points in the Brillouin zone and variation of Fermi velocities of silicene exhibit significant difference from those of graphene. Fermi velocities show strong anisotropy with respect to the wave vector directions and change slightly before the semimetal-metal transition. We also find that the work function of silicene increases monotonously with the increasing uniaxial strains. PACS NUMBERS: 61.46.-w; 62.20.D-; 73.22.Dj.

Lung function and incidence of chronic obstructive pulmonary disease after improved cooking fuels and kitchen ventilation: a 9-year prospective cohort study.

BACKGROUND: Biomass smoke is associated with the risk of chronic obstructive pulmonary disease (COPD), but few studies have elaborated approaches to reduce the risk of COPD from biomass burning. The purpose of this study was to determine whether improved cooking fuels and ventilation have effects on pulmonary function and the incidence of COPD. METHODS AND FINDINGS: A 9-y prospective cohort study was conducted among 996 eligible participants aged at least 40 y from November 1, 2002, through November 30, 2011, in 12 villages in southern China. Interventions were implemented starting in 2002 to improve kitchen ventilation (by providing support and instruction for improving biomass stoves or installing exhaust fans) and to promote the use of clean fuels (i.e., biogas) instead of biomass for cooking (by providing support and instruction for installing household biogas digesters); questionnaire interviews and spirometry tests were performed in 2005, 2008, and 2011. That the interventions improved air quality was confirmed via measurements of indoor air pollutants (i.e., SO2, CO, CO2, NO2, and particulate matter with an aerodynamic diameter of 10 µm or less) in a randomly selected subset of the participants' homes. Annual declines in lung function and COPD incidence were compared between those who took up one, both, or neither of the interventions. Use of clean fuels and improved ventilation were associated with a reduced decline in forced expiratory volume in 1 s (FEV1): decline in FEV1 was reduced by 12 ml/y (95% CI, 4 to 20 ml/y) and 13 ml/y (95% CI, 4 to 23 ml/y) in those who used clean fuels and improved ventilation, respectively, compared to those who took up neither intervention, after adjustment for confounders. The combined improvements of use of clean fuels and improved ventilation had the greatest favorable effects on the decline in FEV1, with a slowing of 16 ml/y (95% CI, 9 to 23 ml/y). The longer the duration of improved fuel use and ventilation, the greater the benefits in slowing the decline of FEV1 (p<0.05). The reduction in the risk of COPD was unequivocal after the fuel and ventilation improvements, with an odds ratio of 0.28 (95% CI, 0.11 to 0.73) for both improvements. CONCLUSIONS: Replacing biomass with biogas for cooking and improving kitchen ventilation are associated with a reduced decline in FEV1 and risk of COPD. TRIAL REGISTRATION: Chinese Clinical Trial Register ChiCTR-OCH-12002398.