Life Cycle assessment of a plastic packaging recycling system

Goal, Scope and Background.  The object of the study is the Italian system of plastic packaging waste recycling, active until 2001, that collected and mechanically recycled the post-consumer PE and PET liquid containers. The phases of collection, compaction, sorting, reprocessing and refuse disposal were individually analysed and quantified in terms of energy and material consumptions as well as of emissions in the environment. The work is the result of a joint research project with the Italian Consortium for Packaging (CONAI), carried out in co-operation with the main Italian companies active in the field. The main aim was the quantification of the real advantage of plastic container recycling and the definition of criteria, at the same time environmentally compatible and economically sustainable, for their management. Main Features  For each of the unit processes, and in order to increase the data quality, all the data of interest were collected during technical visits to several selected plants active in Italy or deduced by official documents and certificate declarations of the same companies. To allow comparison of resource consumption and environmental pollution from different management scenarios producing different products, thebasket of products method was applied. Results  The results indicates that the production of 1 kg of flakes of recycled PET requires a total amount of gross energy that is in the range of between 42 and 55 MJ, depending on whether the process wastes (mainly coming from sorting and reprocessing activities) were sent or not to the energy recovery. The same quantity of virgin PET requires more than 77 MJ. The energetic (and then environmental) saving is so remarkable, even for PE, being 40–49 MJ for the recycled polymer and about 80 MJ that for the virgin polyolefin. The calculations were made with the reasonable assumption that the final utilisation can use the virgin or the recycled polymer without any difference. Conclusions and Outlook  The analysis defined and verified a suitable tool in the field, based on objective data, for comparing different coherent scenarios of waste management politics. This allows one to propose the extension of the tool under different collection schemes, as well as for different systems of packaging recycling. As an immediate consequence of the success of the present study, the joint-research programme with CONAI has been extended for another three years. The focus will be the Italian system for paper and paperboard recycling and that for all plastic packagings. In parallel, a different study has been scheduled with reference to the integrated solid waste management of the Regione Campania, the largest and most populated area in the South of Italy.     

Activation of K+ and Cl− channels in MDCK cells during volume regulation in hypotonic media

Single-channel patch-clamp experiments were performed on MDCK cells in order to characterize the ionic channels participating in regulatory volume decrease (RVD). Subconfluent layers of cultured cells were exposed to a hypotonic medium (150 mOsm), and the membrane currents at the single-channel level were measured in cell-attached experiments. The results indicate that MDCK cells respond to a hypotonic swelling by activating several different ionic conductances. In particular, a potassium and a chloride channel appeared in the recordings more frequently than other channels, and this allowed a more detailed study of their properties in the inside-out configuration of the patch-clamp technique. The potassium channel had a linear I/V curve with a unitary conductance of 24 +/- 4 pS in symmetrical K+ concentrations (145 mM). It was highly selective for K+ ions vs. Na+ ions: PNa/PK less than 0.04. The time course of its open probability (P0) showed that the cells responded to the hypotonic shock with a rapid activation of this channel. This state of high activity was maintained during the first minute of hypotonicity. The chloride channel participating in RVD was an outward-rectifying channel: outward slope conductance of 63.3 +/- 4.7 pS and inward slope conductance of 26.1 +/- 4.9 pS. It was permeable to both Cl- and NO3- and its maximal activation after the hypotonic shock was reached after several seconds (between 30 and 100 sec). The activity of this anionic channel did not depend on cytoplasmic calcium concentration. Quinine acted as a rapid blocker of both channels when applied to the cytoplasmic side of the membrane. In both cases, 1 mM quinine reversibly reduced single-channel current amplitudes by 20 to 30%. These results indicate that MDCK cells responded to a hypotonic swelling by an early activation of highly selective potassium conductances and a delayed activation of anionic conductances. These data are in good agreement with the changes of membrane potential measured during RVD.     

Monitoring airborne genotoxicants in the rubber industry using genotoxicity tests and chemical analyses

This research was designed to examine the presence of mutagenic/carcinogenic compounds in airborne pollutants in the rubber industry using an integrated chemical/biological approach. Inhalable airborne particulate matter (PM-10: <10 μm) was collected in four rubber factories using a high-volume sampler equipped with a cascade impactor for particle fractionation. The organic extracts of two different fractions (0.5–10 μm and <0.5 μm) were examined for mutagenicity with the Ames test and for in vitro DNA-damaging activity in human leukocytes by single-cell microgel electrophoresis (Comet assay). The extracts were also studied by gas chromatography/mass spectrometry (GC/MS) for polycyclic aromatic hydrocarbon (PAH) content. Nitrosamines in ambient air were sampled on cartridges and analysed by GC with a thermal energy analyser (TEA) detector. Airborne volatile genotoxins were monitored in situ using a clastogenicity plant test (Tradescantia/micronuclei test). The results showed that airborne particulates were mainly very fine (<0.5 μm) and that trace amounts of genotoxic nitrosamines (N-nitrosodimethylamine: 0.10–0.98 μg/m³; N-nitrosomorpholine: 0.77–2.40 μg/m³) and PAH (total PAH: 0.34–11.35 μg/m³) were present in air samples. Some extracts, particularly those obtained from the finest fractions, were mutagenic with the Ames test and genotoxic with the Comet assay. In situ monitoring of volatile mutagens using the Tradescantia/micronuclei test gave positive results in two working environments. The results showed the applicability of this integrated chemical–biological approach for detecting volatile and non-volatile genotoxins and for monitoring genotoxic hazards in the rubber industry.     

Calf lens crystallin messenger RNA''s contain polynucleotide sequences rich in adenylic acid

Calf lens messenger fractions have been purified on poly(dT)-cellulose. The purified RNA's have been analyzed as nucleosides by a method which can be used on a micro-scale with highly reproduceble results. Both the 10S and 14S lens mRNA contain poly A sequences. The poly A content found in 14S mRNA cannot account for the excess nucleotides in this message.     

Activation of phosphoinositide-specific phospholipase C of rat neutrophils by the chemotactic aldehydes 4-hydroxy-2,3-trans-nonenal and 4-hydroxy-2,3-trans-octenal

A comparison has been made between the effects of 4-hydroxy-2,3-trans-nonenal (HNE) and 4-hydroxy-2,3-trans-octenal (HOE), two lipid peroxidation products, on the basal and GTPgammaS-stimulated activities of phosphoinositide-specific phospholipase C (PL-C) of rat polymorphonuclear leukocytes. PL-C activity was determined in vitro by measuring the hydrolysis of [³H] phosphatidylinositol-4,5-bis-phosphate (PtdIns-P₂) added as exogenous substrate to neutrophil plasma membranes. PL-C was activated by concentrations of HNE ranging from 10^?8 to 10^?6 M both in the presence and in the absence of 2 × 10^?5 M GTPgammaS; HOE stimulated the enzymatic activity between 10^?11 and 10^?8 M ; maximal stimulation was given by 10^?11 M HOE plus GTPgammaS. The aldehyde concentrations able to accelerate PtdIns-P₂ breakdown displayed a good correspondence with those which have been reported to stimulate the oriented migration of rat neutrophils. Pretreatment of neutrophils with pertussis toxin prevented the stimulation of PL-C by 10^?11 M HOE and by HOE plus GTPgammaS. Our results suggest that the chemotactic action of HNE and HOE might depend on the activation of PL-C; furthermore a regulatory G protein appears to be involved in the acceleration of PtdIns-P₂ turnover by HOE.     

The Polycomb group protein MEDEA controls cell proliferation and embryonic patterning in Arabidopsis

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Comparative growth of the thermal alga Cyanidium caldarium on nitrate and ammonia at different temperatures

Summary The growth of Cyanidium caldarium on nitrate and ammonia as nitrogen sources was studied at different temperatures from 21 to 54°C.Algal growth occurred at temperatures of 24° C or above when ammonia was the nitrogen source, whereas with nitrate, growth occurred at 30° C or above. The optimum and the maximum growth temperatures were 45 and 54° C respectively on both substrates.Arrhenius plots show that the logarithm of the growth rate is not linear with the reciprocal of absolute temperature, but exhibit sharply defined breaks at 30° C on ammonia and at 40° C on nitrate.It is assumed that below 40° C, when Cyanidium grows on nitrate, the utilization of this substrate represents the master reaction which controls the growth rate of the alga.