Polycyclic aromatic hydrocarbons (PAHs) levels in propolis and propolis-based dietary supplements from the Italian market

Propolis and propolis-based extracts, attained from beekeepers and the local market, were analysed for the presence of 13 polycyclic aromatic hydrocarbons (PAHs), including eight high molecular weight PAHs (PAH8), recently indicated by the European Food Safety Authority (EFSA) as suitable indicators of the presence of carcinogenic and genotoxic PAH in foods. An analytical procedure based on microwave assisted saponification/extraction, high performance liquid chromatography (HPLC) and spectrofluorometric detection, has been developed. About half of the samples analysed presented benzo[a]pyrene (BaP) concentrations exceeding 2 μg/kg, which is proposed as a regulatory limit for dietary supplements. A product-by-product approach (based on maximum recommended dosage) was used to calculate PAH exposure. Even thought the majority of the samples gave low exposure levels when compared to exposure levels from other diet constituents, PAH intakes deriving from a daily consumption of some of the investigated products provided an important contribution to the total dietary intake and lead to margin of exposure (MOE) values which are of concern for human health.     

Aroma development in high pressure treated beef and chicken meat compared to raw and heat treated

Chicken breast and beef muscle were treated at 400 and 600 MPa for 15 min at 5 °C and compared to raw meat and a heated sample (100 °C for 15 min). Vacuum-packed beef meat with a smaller fraction of unsaturated fatty acids showed better oxidative stability during 14 days of cold storage, as shown by a low steady-state level of hydroperoxide values, than vacuum-packed chicken meat. Accordingly, the critical pressures of 400 MPa and 600 MPa for chicken breast and beef sirloin, respectively, were established. Volatiles released after opening of the meat bags or during storage of open meat bags, simulating consumer behaviour, were measured under conditions mimicking eating. Quantitative and olfactory analysis of pressurised meat gave a total of 46 flavour volatiles, mainly alcohols (11), aldehydes (15), and ketones (11), but all in low abundance after 14 days of storage. Overall, beef meat contained less volatiles and in lower abundance (factor of 5) compared to chicken meat. The most important odour active volatiles (GC-O) were well below the detection thresholds necessary to impart a perceivable off-flavour. Lipid oxidation was significantly accelerated during 24 h of cold storage in both cooked chicken and beef when exposed to oxygen, while the pressurised and oxygen-exposed chicken and beef meat remained stable. Pressure treatment of beef and chicken did not induce severe changes of their raw aroma profiles.     

Galactose derivative immobilized glow discharge processed polyethersulfone membranes maintain the liver cell metabolic activity

New strategies aimed to surface modification of polymeric membranes are crucial to optimise cell-biomaterial interactions in vivo and in vitro biohybrid systems. In this paper, we investigated the surface modification of Polyethersulfone (PES) membranes by plasma polymerisation of acrylic acid monomers (PES-pdAA) and by immobilization of galactonic acid through a hydrophilic "spacer arm" molecule (PES-pdAA-SA-GAL). The modification steps were characterised by high resolution X-ray photoelectron spectroscopy. The performance of modified and unmodified membranes was evaluated by assessing the expression of liver specific biotransformation functions of pig and human hepatocytes. Human liver cells cultured on PES-pdAA-SA-GAL membranes displayed an enhanced albumin production, urea synthesis and protein secretion for 24 days of culture. The immobilisation of galactose derivative units on the membrane allowed specific interactions with hepatocytes biomimicking the cellular microenvironment and produced an improvement of the long-term maintenance and differentiation of human hepatocytes.     

Fate of pentabrominated diphenyl ethers in soil: abiotic sorption, plant uptake, and the impact of interspecific plant interactions

Polybrominated diphenyl ethers (PBDEs) are potentially harmful and persistent environmental pollutants. Despite evidence that soils are a major sink for PBDEs, little is known regarding their behavior in this medium. An environmentally relevant level of a commercial penta-BDE mixture (75 microg kg(-1)) was added to topsoil, and the extractability of three congeners (BDE-47, -99, and -100) was monitored over 10 weeks in planted and unplanted treatments. The extractability of each congener decreased rapidly in the experimental soil due largely to abiotic sorption to soil particles, which was demonstrated by low PBDE recovery from sterilized and dry soils. Monoculture plantings of zucchini and radish did not affect the recovery of PBDEs from soil. However, PBDE recovery from mixed species plantings was nearly 8 times higher than that of unplanted and monoculture treatments, indicating that interspecific plant interactions may enhance PBDE bioavailablity in soil. Evidence for competitive interactions between the two species was revealed by reduced shoot biomass of zucchini plants in mixed treatments relative to pots containing only zucchini. Both plant species accumulated PBDEs in root and shoot tissue (<5 microg kg(-1) plant tissue). PBDE uptake was higher in zucchini, and translocation of PBDEs to zucchini shoots was congener-specific. Our results suggest that although abiotic sorption may limit the potential for human exposure to PBDEs in soil, plants may increase the exposure risk by taking up and translocating PBDEs into aboveground tissues and by enhancing bioavailability in soil.     

Iridium‐Catalyzed Allylic Amination Route to α‐Aminoboronates: Illustration of the Decisive Role of Boron Substituents

The development of a new route to α‐aminoboronates using an iridium‐catalyzed allylic amination on boronated substrates is described. Unlike the boronate group, the trifluoroborato substituent was found to govern the regioselectivity exclusively in favor of branched products. The transformation of an allylic substitution product into an α‐aminoboronic ester in an efficient way validated the implementation of this approach.     

The CFAR adaptive subspace detector is a scale-invariant GLRT

The constant false alarm rate (CFAR) matched subspace detector (CFAR MSD) is the uniformly most-powerful-invariant test and the generalized likelihood ratio test (GLRT) for detecting a target signal in noise whose covariance structure is known but whose level is unknown. Previously, the CFAR adaptive subspace detector (CFAR ASD), or adaptive coherence estimator (ACE), was proposed for detecting a target signal in noise whose covariance structure and level are both unknown and whose covariance structure is estimated with a sample covariance matrix based on training data. We show here that the CFAR ASD is GLRT when the test measurement is not constrained to have the same noise level as the training data, As a consequence, this GLRT is invariant to a more general scaling condition on the test and training data than the well-known GLRT of Kelly (1986)     

Verwertung von Magnesiumschrott

Utilization of magnesium scrap At present the applications of magnesium alloys grow rapidly. Therefore the recycling of magnesium gets new importance. Starting from the demand of magnesium alloys the material cycle of magnesium including the primary production, the consumption and the recycling is presented. Scrap classes and ways for the utilization of new scrap, post consumer scrap, residues and magnesium alloy scrap containing valuable alloying elements like rare earth and lithium are proposed.     

Macroporous polyamines containing cyclodextrin: Synthesis,characterization, and sorption properties

Macroporous beads containing N-vinyl-tertio-butyl carbamate (NVTBC) have been prepared by suspension copolymerization using divinylbenzene as crosslinking agent. After solvolysis, parent copolymers containing vinylamine (VA) were functionalized by β-cyclodextrin (β-CD) using the mono-tosyl derivative of β-CD as the intermediate (β-CDOTs). Several copolymers with various degrees of substitution were synthesized. Several factors (reaction time, amounts of the reactants, composition of solvent, and temperature) were studied. Characterization was achieved by crosspolarization magic angle spinning nuclear magnetic resonance spectroscopy (CPMAS NMR). The textural features (specific area and porous volume) of the beads were also determined. These insoluble macroporous copolymers containing β-CD were then used for the recovery of various organic pollutants from aqueous solutions. Some preliminary studies (time, concentration, kinetics, and β-CD content) are presented here. The results of sorption experiments show that they exhibit high sorption capacities toward substituted benzene derivatives. The mechanism of sorption is an acid-base interaction due to the amino groups of the polymer network and/or the formation of an inclusion complex due to the β-CD molecules. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 1419–1427, 1998     

Development of stabilized zirconia–alkali salts dual membranes for carbon dioxide capture

Molten Na₂CO₃–K₂CO₃ (NKC, 56–44 mol%) eutectic compositions were vacuum-impregnated, at the eutectic temperature, into two porous ZrO₂:8.6 mol% MgO (magnesium-partially stabilized zirconia, MgPSZ) and ZrO₂:8 mol% Y₂O₂ (yttria-fully stabilized zirconia, 8YSZ) ceramics. Thermogravimetric analyses were performed in mixtures of that composition with MgPSZ and 8YSZ ceramic powders. Before impregnation, porosity was achieved in the two compounds by addition and thermal removal of 30 vol.% NKC. To ascertain the carbonates had filled up through the ceramic body, both sides of the parallel and fracture surfaces of the disk-shaped impregnated compositions were observed in a scanning electron microscope and analyzed by energy-dispersive X-ray spectroscopy. The electrical conductivity of the two ceramics, before and after impregnation, was evaluated by electrochemical impedance spectroscopy in the 5 Hz–13 MHz frequency range from approximately 530 to 740°C. The permeation of the carbonate ions through the membranes via the eutectic composition was assessed by the threshold temperatures of the onset of the carbonate ion percolation. The objectives were to prepare dual-phase membranes for the separation of carbon dioxide and for the development of carbon dioxide sensors.     

Anti-biofilm Activity of Human Milk Oligosaccharides in Clinical Strains of Streptococcus agalactiae with Diverse Capsular and Sequence Types

Group B Streptococcus (GBS) is an encapsulated Gram-positive bacterial pathogen that causes severe perinatal infections. Human milk oligosaccharides (HMOs) are short-chain sugars that have recently been shown to possess antimicrobial and anti-biofilm activity against a variety of bacterial pathogens, including GBS. We have expanded these studies to demonstrate that HMOs can inhibit and dismantle biofilm in both invasive and colonizing strains of GBS. A cohort of 30 diverse strains of GBS were analyzed for susceptibility to HMO-dependent biofilm inhibition or destruction. HMOs were significantly effective at inhibiting biofilm in capsular-type- and sequence-type-specific fashion, with significant efficacy in CpsIb, CpsII, CpsIII, CpsV, and CpsVI strains as well as ST-1, ST-12, ST-19, and ST-23 strains. Interestingly, CpsIa as well as ST-7 and ST-17 were not susceptible to the anti-biofilm activity of HMOs, underscoring the strain-specific effects of these important antimicrobial molecules against the perinatal pathogen Streptococcus agalactiae.