The influence of yttrium (Y) on the corrosion of Mg-Y binary alloys

Corrosion of Mg-Y alloys was studied using electrochemical evaluations, immersion tests and direct observations. There were two important effects. In 0.1 M NaCl, the corrosion rate increased with increasing Y content due to increasing amounts of the Y-containing intermetallic. In 0.1 M Na₂SO₄, the corrosion rate decreased with increasing Y content above 3%, attributed to a more protective surface film, despite the intermetallic. The corrosion rate evaluated by electrochemical impedance spectroscopy was somewhat smaller than that evaluated from H evolution as expected from the Mg corrosion mechanism. A mechanism is proposed for filiform corrosion. Direct in situ corrosion observations revealed that a predominant feature was hydrogen evolution from particular parts of the alloy surface.     

Non-intrusive headspace gas measurements by laser spectroscopy – Performance validation by a reference sensor

The oxygen concentration in the headspace of a large number of liquid food containers is assessed with non-intrusive diode laser absorption spectroscopy. The results are compared to those given by a traditional intrusive measurement method. The upper portions of the containers are made of translucent but non-transparent plastic materials, through which the laser light is diffusively transmitted. Measurements are performed both on packages with modified atmosphere and with normal air conditions. It is concluded that the novel non-intrusive technique provides oxygen concentrations that generally differ by less than one percentage point from the reference sensor values.     

Measurement of evaporated acrylamide during heat treatment of food and other biological materials

It is established that acrylamide could be formed during heating of food products. In the present work we have studied whether the formed acrylamide could evaporate from food at elevated temperatures used in cooking (>160 °C) or used in determination of dry matter in laboratory analysis (ca. 105 °C). It was demonstrated that acrylamide evaporates from food samples during both cooking and temperatures used for drying. Up to ca. 4 μg/m³ could be measured above the fry pan during frying of potato. In parallel we have also studied whether acrylamide could be formed and evaporate during the elevated temperatures of 65-130 °C used for dry matter determinations in other types of samples containing biological material, like agricultural and environmental samples. It was found that acrylamide is formed during conditions for drying of soil, sediment and silage samples, as well as cereals, animal feed, etc. After drying, levels of acrylamide up to about 100 μg/kg were found, e.g. in samples of sediment and sludge. The measurements showed in the food, agricultural and environmental samples tested a minor fraction, roughly estimated to be 0.15-7.2% of the formed acrylamide evaporates at the used elevated temperatures.     

In vitro analysis of inflammatory responses following environmental exposure to pharmaceuticals and inland waters

Pharmaceuticals are regularly released into the environment; in particular non-steroidal anti-inflammatory drugs (NSAIDs) and antibiotics. Erythromycin, naproxen, furosemide and atenolol are reported to be stable for up to 1 year in the environment, which increases the risk for accumulation. In the present study we have measured the occurrence and concentration of pharmaceuticals in river Viskan (Jössabron) downstream of a sewage treatment plant in Borås, Sweden. Pharmaceuticals and water samples were tested for potential human risk by evaluating inflammatory responses (NF-κB and AP-1) using human T24 bladder epithelial cells and Jurkat T-cells. NF-κB activity in T24 cells was significantly reduced by all NSAIDs analysed (diclofenac, ketoprofen, naproxen, ibuprophen and dextropropoxyphene), but also by trimethoprim, using environmentally relevant concentrations. NF-κB and AP-1 activation was further analysed in response to water samples collected from different locations in Sweden. Dose-dependent down-regulation of AP-1 activity in Jurkat cells was observed at all locations. At two locations (Jössabron and Almenäs) down-regulation of NF-κB was observed. In contrast, the NF-κB response was potentiated by exposure to water from both locations following activation of NF-κB by treatment with heat-killed Escherichia coli. To determine the involvement of pharmaceuticals in the responses, T24 cells were exposed to the pharmaceutical mixture, based on the determined levels at Jössabron. This resulted in reduction of the NF-κB response following exposure to the pharmaceutical mixture alone while no potentiation was observed when cells were co-exposed to heat killed E. coli and pharmaceuticals. The obtained results demonstrate that the identified pharmaceuticals affect the inflammatory responses and furthermore indicate the presence of unknown substance(s) with the ability to potentiate inflammatory responses.     

Physical-Chemical Characterization and Polymorphism Determination of Two Nimodipine Samples Deriving from Distinct Laboratories

Knowing the characteristics of raw materials in pharmaceutical practice is both important and useful. Firstly, evaluating the physical-chemical properties of the substances that will be used must be the primary step for quality control in the pharmacy industry. This work aims at analyzing the physical-chemical characteristics of two nimodipine samples I and II derived from distinct laboratories through thermal analysis (DSC and TG/DTG), HPLC, crystallography, and microscopy. Thermal analysis showed that sample II was more unstable than I. Morphological differences concerning shape, size, and crystallinity of particles were visualized by scanning electron microscopy (SEM) and X-ray powder diffraction. To sum up, the techniques used in this study can be said to have been efficient in the characterization and evaluation of quality control of the raw material.     

Synthesis and growth mechanism of differently shaped C60 nano/microcrystals produced by evaporation of various aromatic C60 solutions

We present a detailed study of the synthesis of C₆₀ nano- and microrods as well as crystals with normal shapes by the evaporation of C₆₀ solutions based on different aromatic solvents. C₆₀ nano- and microrods are grown with high yield by vaporizing C₆₀ solutions in meta-isomers of aromatic solvents on different substrates while para-isomers give a different type of growth leading to highly crystalline two- and three-dimensional nano- and microcrystals with fcc structure. The role of solvent properties was investigated by using positional isomers containing different halogen radicals. The as-grown crystal rods form hexagonal structures but transform into fcc structure on annealing in vacuum. IR and EDX analysis indicate that solvents remain in the hexagonal nano- and microrods, while it is hard to detect any trace of solvents in the two- or three-dimensional nano- and microcrystals. Furthermore, we present direct proof of the nucleation-growth mechanism for C₆₀ rods. By the vaporization method, the solubility of C₆₀ in the studied halogen aromatic solvents is found to correlate with the diameter distribution of the C₆₀ rods and we suggest that the chemical affinity of the aromatic solvent molecules to C₆₀ may determine its ability to force C₆₀ to form rod-shaped crystals.