Lung adenocarcinoma promotion by air pollutants

A complete understanding of how exposure to environmental substances promotes cancer formation is lacking. More than 70 years ago, tumorigenesis was proposed to occur in a two-step process: an initiating step that induces mutations in healthy cells, followed by a promoter step that triggers cancer development1. Here we propose that environmental particulate matter measuring ≤2.5 μm (PM2.5), known to be associated with lung cancer risk, promotes lung cancer by acting on cells that harbour pre-existing oncogenic mutations in healthy lung tissue. Focusing on EGFR-driven lung cancer, which is more common in never-smokers or light smokers, we found a significant association between PM2.5 levels and the incidence of lung cancer for 32,957 EGFR-driven lung cancer cases in four within-country cohorts. Functional mouse models revealed that air pollutants cause an influx of macrophages into the lung and release of interleukin-1β. This process results in a progenitor-like cell state within EGFR mutant lung alveolar type II epithelial cells that fuels tumorigenesis. Ultradeep mutational profiling of histologically normal lung tissue from 295 individuals across 3 clinical cohorts revealed oncogenic EGFR and KRAS driver mutations in 18% and 53% of healthy tissue samples, respectively. These findings collectively support a tumour-promoting role for PM2.5 air pollutants and provide impetus for public health policy initiatives to address air pollution to reduce disease burden

Effect of low oxygen, temperature and 1-methylcyclopropene on the expression of genes regulating ethylene biosynthesis and perception during ripening in apple

AbstractEthylene initiates and controls ripening in climacteric fruit which is developmentally regulated. During this process, ethylene production generates a strong signaling process inducing/suppressing various target genes that are associated with several attributes of fruit ripening. In apple, low temperature, low oxygen and 1-methylcyclopropene (1-MCP) treatments have been used to increase shelf life. In the present study, effort has been made to understand the molecular basis of the increase in shelf life under the influence of temperature, low oxygen and 1-MCP in Granny Smith apple. The apple fruit were exposed to these treatments either individually or in combination and levels of ethylene as well as transcript accumulation of the genes responsible for ethylene biosynthesis and ethylene receptors were measured. A tight regulation of the ethylene production was observed through differential expression of MdACS1 and MdERS1 genes. The ethylene levels were highly dependent on temperature, oxygen concentration and 1-MCP and effects of each were not only additive but associated with the expression of MdACS1 and MdERS1

FTIR and dielectric relaxation analysis for PVC-Pb3O4 polymer nanocomposites

Abstract This work studies the FTIR as well as dielectric characteristics of the PVC-Pb3O4 nanocomposite films. FTIR analysis shows the small shift in 650, 845 and 1732 cm− 1 band positions as a confirmation of interaction between Pb3O4 nanoparticles with PVC polymer matrix. The real permittivity (ε1) decreases with increasing frequency for all samples with the appearance of a relaxation peak at high temperatures. The dielectric loss data (ε2) of the PVC-Pb3O4 nanocomposite revealed a shift of the dielectric absorption peak towards high frequency with increasing the temperature. The activation energy values for both α and β relaxations almost decreased with increasing the Pb3O4 concentration. The energy density of samples containing Pb3O4 has a lower energy density than the pure PVC polymer film. The exponent s often increased with increasing the temperature, and this behavior is consistent with overlapping large-polaron tunneling model. The DC activation energy decreased when the percentage of Pb3O4 increased to 3.0 wt% and then increased at 4.0 wt%. Additionally, a convergence between these values and the activation energies of α and β relaxations observed, which is indicates that the same type of charge carriers participate in the processes.</jats:p

CuO nanoflowers as an electrochemical pH sensor and the effect of pH on the growth

Well-crystallized flower-shaped cupric oxide (CuO) nanostructures composed of thin leaves have been synthesized by simple low-temperature chemical bath method and used to fabricate pH sensor. We examined the effect of the pH on the growth of the CuO nanostructures, by changing the pH of the precursor solutions different morphologies of the CuO nanostructures were obtained. CuO nanoflowers have recently become important as a material that provides an effective surface for electrochemical activities with enhanced sensing characteristics. The proposed sensor exhibited a linear electrochemical response within a wide pH range of (2-11). The experimental results (time response, electrochemical activity, reproducibility, absorption spectra, and XRD) indicate that the CuO nanoflowers can be used in pH sensor applications with enhanced properties