Contamination in plastic recycling: Influence of metals on the quality of reprocessed plastic.

The global consumption of plastic continues to increase, and plastic recycling is highlighted as crucial for saving fossil resources and closing material loops. Plastic can be made from different polymers and contains a variety of substances, added intentionally to enhance the plastic's properties (metals added as fillers, colourants, etc.). Moreover, plastic can be contaminated during use and subsequent waste management. Consequently, if substances and contaminants are not removed during recycling, potentially problematic substances might be recycled with the targeted polymers, hence the need for quantitative data about the nature and presence of these substances in plastic. Samples of selected polymers (PET, PE, PP, PS) were collected from different origins; plastic household waste, flakes/pellets of reprocessed plastic from households and industry, and virgin plastic. Fifteen selected metals (Al, As, Cd, Co, Cr, Cu, Fe, Hg, Li, Mn, Ni, Pb, Sb, Ti, Zn) were quantified and the statistical analysis showed that both the polymer and origin influenced the metal concentration. Sb and Zn were potentially related to the production stage of PET and PS, respectively. Household plastic samples (waste and reprocessed) were found to contain significantly higher Al, Pb, Ti and Zn concentrations when compared to virgin samples. Only the concentration of Mn was reduced during washing, suggesting that parts of it was present as physical contamination. While most of the metals were below legal limit values, elevated concentrations in reprocessed plastic from households, aligned with increasing recycling rates, may lead to higher metal concentrations in the future.

Quantification of chemical contaminants in the paper and board fractions of municipal solid waste.

Chemicals are used in materials as additives in order to improve the performance of the material or the production process itself. The presence of these chemicals in recyclable waste materials may potentially affect the recyclability of the materials. The addition of chemicals may vary depending on the production technology or the potential end-use of the material. Paper has been previously shown to potentially contain a large variety of chemicals. Quantitative data on the presence of chemicals in paper are necessary for appropriate waste paper management, including the recycling and re-processing of paper. However, a lack of quantitative data on the presence of chemicals in paper is evident in the literature. The aim of the present work is to quantify the presence of selected chemicals in waste paper derived from households. Samples of paper and board were collected from Danish households, including both residual and source-segregated materials, which were disposed of (e.g., through incineration) and recycled, respectively. The concentration of selected chemicals was quantified for all of the samples. The quantified chemicals included mineral oil hydrocarbons, phthalates, phenols, polychlorinated biphenyls, and selected toxic metals (Cd, Co, Cr, Cu, Ni, and Pb). The results suggest large variations in the concentration of chemicals depending on the waste paper fraction analysed. Research on the fate of chemicals in waste recycling and potential problem mitigation measures should be focused on in further studies.

Angiogenic factors in relation to clinical effect in a phase II trial of weekly paclitaxel.

BACKGROUND: Several anticancer agents including paclitaxel have an inhibitory effect on angiogenesis. AIMS: To compare the overall response rate and time to progression with changes in circulating angiogenic factors during palliative treatment with weekly paclitaxel. MATERIAL AND METHODS: Patients with metastatic BC, ECOG 0-2, received weekly paclitaxel, concomitant with trastuzumab if HER2+ BC (n = 7). Circulating vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) were determined at base-line and before start of new course. RESULTS: Fifty-five of 63 included patients were evaluable. The overall response rate including stable disease ≥24 weeks (CR + PD + SD) was obtained in 25 of the evaluable patients (45%). The median time to progression (TTP) was 5.3 months and overall survival (OS) 16.7 months. Patients with triple negative breast cancer (TNBC) showed a trend towards higher base-line VEGF compared with hormone receptor positive or HER2+ tumours and had shorter TTP. Significant differences in VEGF and bFGF levels at 12 weeks were found between patients with longer versus shorter TTP (VEGF: p = 0.046, bFGF: p = 0.005) and between patients gaining versus lacking clinical benefit (VEGF: p = 0.05, bFGF: p = 0.02). CONCLUSIONS: The clinical utility of circulating VEGF may be a useful tool for monitoring treatment efficacy.

Molecular cloning and expression analysis of three omega-6 desaturase genes from purslane (Portulaca oleracea L.).

Two full-length cDNA clones of PoleFAD2 and one full-length cDNA clone of PoleFAD6, encoding omega-6 fatty acid desaturases, the key enzymes for the conversion of oleic into linoleic acid, were isolated from purslane (Portulaca oleracea L.) leaves and seeds. The deduced amino acid sequence of both isoforms of PoleFAD2 showed higher similarities to other microsomal omega-6 desaturases then to PoleFAD6 or other plastidial orthologues, and vice versa. Expression analysis by RT-PCR showed that all genes are expressed in all tissues of purslane tested, but higher levels of mRNA accumulation were detected in reproductive organs and cells that proliferate rapidly or store lipids. Wounding affected the levels of mRNA accumulation of both, FAD2 and FAD6 genes in purslane leaves, while chilling stress affected only FAD2 transcript level. The expression patterns observed reflect the discrete roles of these genes in membrane synthesis for cell division, thylakoid development, and lipid storage or in the biosynthetic pathway for the production of signaling molecules that influence plant development or defense.

Plasma amino acid response to single test meals in humans. VI. Determination of available lysine.

The plasma amino acid response to single test meals in young adults was used to determine the amount of physiologically available lysine in heat-treated milk samples. The plasma amino acid responses were evaluated as PAA ratios according to a modified calculation procedure based on the method proposed by Longenecker and Hause. The amount of available lysine was determined by two separate series of single-meal tests. In the first, a relationship was established between the plasma amino acid response (PAA ratio) and the dietary level of lysine (given as synthetic amino acid mixtures). This relationship could be described by linear regression (r = 0.90). This regression line was then used to quantitatively evaluate the lysine PAA ratios obtained from single test meals with heat-treated milk samples. The heat-treatment of the milk samples caused a marked reduction of the amount of physiologically available lysine. The quantitative estimates obtained by the present plasma amino acid technique were in good agreement with determinations of available lysine in the same milk samples based on rat bioassay and chemical analysis.

Plasma amino acid response to single test meals in humans. III. Supplementary effect of dried skim milk and L-methionine on a vegetable protein mixture.

The plasma amino acid response to single test meals in young adults was used for human biological evaluation of the supplementary effect of dried skim milk powder (DSM) and synthetic L-methionine on a vegetable protein mixture. The protein sources in the vegetable mixture were wheat flour, defatted soya bean flour and pea flour. The plasma amino acid responses were evaluated both as PAA ratios (a modification of the Longenecker and Hause method), and as delta MR% (percentage change in the postprandial essential amino acid molar ratios according to Graham and Placko). Both evaluation methods indicated that there was an adequate supply of all the essential amino acids in the basic vegetable mixture, except for a small deficit of methionine. Supplementation (5% and 10%) with DSM did not significantly improve the low plasma amino acid response of methionine. The addition of synthetic L-methionine proved to be very effective in this respect. 1 g of L-methionine per 100 g of proteins from the vegetable mixture gave a plasma methionine response similar to that of the other essential amino acids. This implies that the deficit of methionine in the basic wheat/soya bean/pea mixture was about 30%.