Airborne trace elements near a petrochemical industrial complex in Thailand assessed by the lichen Parmotrema tinctorum (Despr. ex Nyl.) Hale

7siSeveral trace elements discharged by the petrochemical industry are toxic to humans and the ecosystem. In this study, we assessed airborne trace elements in the vicinity of the Map Ta Phut petrochemical industrial complex in Thailand by transplanting the lichen Parmotrema tinctorum to eight industrial, two rural, and one clean air sites between October 2013 and June 2014. After 242 days, the concentrations of As, Cd, Co, Cr, Cu, Hg, Mo, Ni, Pb, Sb, Ti, V, and Zn in lichens at most industrial sites were higher than those at the rural and the control sites; in particular, As, Cu, Mo, Sb, V, and Zn were significantly higher than at the control site (p < 0.05). Contamination factors (CFs) indicated that Cd, Cu, Mo, and Sb, which have severe health impacts, heavily contaminated at most industrial sites. Principal component analysis (PCA) showed that most elements were associated with industry, with lesser contributions from traffic and agriculture. Based on the pollution load indexes (PLIs), two industrial sites were highly polluted, five were moderately polluted, and one had a low pollution level, whereas the pollution load at the rural sites was comparable to background levels. This study reinforces the utility of lichens as cost-effective biomonitors of airborne elements, suitable for use in developing countries, where adequate numbers of air monitoring instruments are unavailable due to financial, technical, and policy constraints.partially_openopenBoonpeng, Chaiwat; Polyiam, Wetchasart; Sriviboon, Chutima; Sangiamdee, Duangkamon; Watthana, Santi; Nimis, Pier Luigi; Boonpragob, KansriBoonpeng, Chaiwat; Polyiam, Wetchasart; Sriviboon, Chutima; Sangiamdee, Duangkamon; Watthana, Santi; Nimis, Pierluigi; Boonpragob, Kansr

Multiaxial mechanical behavior of human fetal membranes and its relationship to microstructure

This study was directed to the measurement of the mechanical response of fetal membranes to physiologically relevant loading conditions. Characteristic mechanical parameters were determined and their relation to the microstructural constituents collagen and elastin as well as to the pyridinium cross-link concentrations analyzed. 51 samples from twelve fetal membranes were tested on a custom-built inflation device, which allows mechanical characterization within a multiaxial state of stress. Methods of nonlinear continuum mechanics were used to extract representative mechanical parameters. Established biochemical assays were applied for the determination of the collagen and elastin content. Collagen cross-link concentrations were determined by high-performance liquid chromatography measurements. The results indicate a distinct correlation between the mechanical parameters of high stretch stiffness and membrane tension at rupture and the biochemical data of collagen content and pyridinoline as well as deoxypyridinoline concentrations. No correlation was observed between the mechanical parameters and the elastin content. Moreover, the low stretch stiffness is, with a value of 105 ± 31 × 10(-3) N/ mm much higher for a biaxial state of stress compared to a uniaxial stress configuration. Determination of constitutive model equations leads to better predictive capabilities for a reduced polynomial hyperelastic model with only terms related to the second invariant, I (2), of the right Cauchy-Green deformation tensor. Relevant insights were obtained on the mechanical behavior of fetal membranes. Collagen and its cross-linking were shown to determine membrane's stiffness and strength for multiaxial stress states. Their nonlinear deformation behavior characterizes the fetal membranes as I (2) material