Environmentally friendly plasticizers for poly(vinyl chloride)—Improved mechanical properties and compatibility by using branched poly(butylene adipate) as a polymeric plasticizer

Linear and branched poly(butylene adipate)s (PBA) with molecular weights ranging from 2000 to 10,000 g/mol, and a branching agent content between 0 and 1.8%, were solution cast with poly(vinyl chloride) (PVC) to form 50‐ to 60‐μm thick flexible films. Dry films were analyzed by tensile testing, Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and optical microscopy (OM) to study the effects of molecular weight and branching on the plasticizing efficiency of the polyester. PBA formed a semimiscible two‐phase system with PVC, where the amorphous part exhibited a single glass transition temperature. The degree of crystallinity for the polyester, surface composition, and mechanical properties of the films depended on the blend composition, molecular weight, and degree of branching of the polyester. Plasticizing efficiency was improved by higher degree of branching. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2180–2188, 2006     

Size-dependent cytotoxicity of gold nanoparticles

Gold nanoparticles are widely used in biomedical imaging and diagnostic tests. Based on their established use in the laboratory and the chemical stability of Au(0), gold nanoparticles were expected to be safe. The recent literature, however, contains conflicting data regarding the cytotoxicity of gold nanoparticles. Against this background a systematic study of water-soluble gold nanoparticles stabilized by triphenylphosphine derivatives ranging in size from 0.8 to 15 nm is made. The cytotoxicity of these particles in four cell lines representing major functional cell types with barrier and phagocyte function are tested. Connective tissue fibroblasts, epithelial cells, macrophages, and melanoma cells prove most sensitive to gold particles 1.4 nm in size, which results in IC(50) values ranging from 30 to 56 microM depending on the particular 1.4-nm Au compound-cell line combination. In contrast, gold particles 15 nm in size and Tauredon (gold thiomalate) are nontoxic at up to 60-fold and 100-fold higher concentrations, respectively. The cellular response is size dependent, in that 1.4-nm particles cause predominantly rapid cell death by necrosis within 12 h while closely related particles 1.2 nm in diameter effect predominantly programmed cell death by apoptosis.     

Sustaining area-based initiatives by developing appropriate “anchors”: the role of social capital

This paper focuses on “anchoring”, understood as the process of building project-based organizational networks, or “anchors”, in order to sustain the efforts of area-based initiatives (ABIs) after they leave their targeted neighbourhoods. Drawing on the scholarly literature on social capital and an empirical examination of three different cases from an ABI in Copenhagen, the paper highlights why and how particular models of “anchors” develop in specific local contexts. We conclude by emphasizing the value of the lens of social capital, particularly, in the ABIs’ strategic efforts towards “anchoring”.     

Replacement predictions for drinking water networks through historical data

Lifetime distribution functions and current network age data can be combined to provide an assessment of the future replacement needs for drinking water distribution networks. Reliable lifetime predictions are limited by a lack of understanding of deterioration processes for different pipe materials under varied conditions. An alternative approach is the use of real historical data for replacement over an extended time series. In this paper, future replacement needs are predicted through historical data representing more than one hundred years of drinking water pipe replacement in Gothenburg, Sweden. The verified data fits well with commonly used lifetime distribution curves. Predictions for the future are discussed in the context of path dependence theory.     

Adsorption of Novel Alkylaminoamide Sugar Surfactants at Tailor-made Surfaces

N,N-di(3-aminopropyl)dodecylamine (C12-Y-amine), N-dodecyl-N,N-di[(3-d-gluconylamido)propyl]amine (C12-DGA), N-dodecyl-N,N-bis[(3-lactobionylamido)propyl]amine (C12-DLA), N-dodecyl-N-[(3-lactobionylamido)propyl]amine (C12-LA), and ethoxylated N,N-di(3-aminopropyl)dodecylamine [C12-Y-amine with 4 and 8 ethylene oxide (EO)] have been synthesized, and their physical-chemical properties have been studied. Adsorption was measured at the air–water interface by the du Noüy ring method and at solid surfaces consisting of self-assembled monolayers (SAMs) of alkanethiols on gold using surface plasmon resonance. Results from surface tension measurements showed that adsorption at the air–water interface is pH dependent. At low pH, reduction in surface tension is less pronounced as a result of protonation of the amino groups of the surfactants. At the SAM model surfaces, generated by adsorption of alkanethiols or mixtures of alkanethiols on gold presenting methyl, hydroxyl, and carboxyl groups, the highest amount of adsorbed surfactant was obtained on a surface composed of a mixture of methyl and carboxyl groups. In general, the sugar-derived surfactants, DGA, DLA, and LA, adsorbed less than the ethoxylates. Surfactant biodegradation was investigated by the closed bottle test. Only C12-Y-amine was found to be readily biodegradable. However, the polyol surfactants were more biodegradable than the ethoxylates.

Corrosion of carbon steel underneath a lead/potassium chloride salt mixture

High amounts of lead in waste/recycled wood fuel are known to be a contributing factor to the increased corrosion often related to this type of fuel. In combination with potassium, usually present in the fuel, low‐melting point salt mixtures between lead chloride (PbCl ₂) and potassium chloride (KCl) are expected to form. The purpose of this study is to investigate reactions in the mixed salt of PbCl ₂ and KCl and its interactions with carbon steel P265GH and its oxide. Laboratory exposures were performed in an isothermal tube furnace with a salt mixture of PbCl ₂/KCl (50/50 mol%) put on steel samples. The test duration was 24 hr at either 300°C or 340°C in an atmosphere of 100 ppm HCl and 20 vol% H ₂O in synthetic air. After exposure, the salt mixture consists of distinct areas of KCl and PbCl ₂ but also the compounds K ₂PbCl ₄ and KPb ₂Cl ₅. A general observation is that the oxide thickness increases with temperature and that areas with Pb/K‐mixed salt are frequently found in close connection to more corroded areas. Often the more lead‐rich phase KPb ₂Cl ₅ is located closest to the corrosion product indicating its importance for the corrosion.     

Manganese chloride tetrahydrate (CMC-001) enhanced liver MRI: evaluation of efficacy and safety in healthy volunteers

Object

To evaluate the efficacy of three dose levels of the oral hepatobiliary manganese-based magnetic resonance imaging (MRI) contrast agent CMC-001, and assess its safety profile and patient acceptability.

Materials and methods

After ethics committee approval, 32 healthy volunteers (males/females: 18/14) were included. Liver MRI was performed before and 3?h after ingestion of 0.8, 0.4, and 0.2?g of CMC-001 on separate occasions. Liver-to-muscle signal intensity (SI) ratio from baseline to post-contrast and image quality was assessed. Adverse drug reactions/adverse events (ADRs/AEs) and clinico-laboratory tests were monitored.

Results

The increase in liver-to-muscle SI ratio was significantly higher after 0.8?g (0.696) compared to 0.4?g (0.458) and 0.2?g (0.223) (in all pair-wise comparisons, P?Conclusion Liver MRI using 0.8?g CMC-001 has the highest efficacy and still acceptable ADRs and should therefore be preferred.     

PAHs in air and seawater along a North-South Atlantic transect: trends, processes and possible sources

Polycyclic aromatic hydrocarbons (PAHs) were simultaneously measured in air and surface seawater between 49 degrees N and 25 degrees S in the open Atlantic Ocean. Elevated concentrations of PAHs (sigma10 PAHs approximately 1.4-2.5 ng m(-3) air, and 0.7-1 ng L(-1) seawater) occurred in the Biscay Bay and off the northwest coast of Africa. The unexpectedly high concentrations off NW Africa were discussed assessing the possible contribution of the emerging oil industry along the African shore, the role of biomass burning and natural sources of PAHs. In the southern Atlantic, concentrations of PAHs were close to detection limits (sigma10 PAHs approximately 0.02-0.5 ng m(-3) air, and 0.06-0.5 ng L(-1) seawater) and showed decreasing trends with increasing latitudes. Correlations of PAHs' partial pressures versus inverse temperature were not significant in contrast to results for polychlorinated biphenyls from the same transect. This could have been due to the importance of ongoing primary sources and the shorter atmospheric life-times of PAHs. Air-water fugacity ratios (fa/fw) were calculated for selected compounds. They were close to 1 for fluoranthene and pyrene in remote open ocean areas suggesting air-water partitioning near equilibrium. Ratios for anthracene and phenanthrene were < 0.3 in the remote tropical Atlantic, suggesting net volatilization.