Time-dependent integrity during storage of natural surface water samples for the trace analysis of pharmaceutical products, feminizing hormones and pesticides

Monitoring and analysis of trace contaminants such as pharmaceuticals and pesticides require the preservation of the samples before they can be quantified using the appropriate analytical methods. Our objective is to determine the sample shelf life to insure proper quantification of ultratrace contaminants. To this end, we tested the stability of a variety of pharmaceutical products including caffeine, natural steroids, and selected pesticides under refrigerated storage conditions. The analysis was performed using multi-residue methods using an on-line solid-phase extraction combined with liquid chromatography tandem mass spectrometry (SPE-LC-MS/MS) in the selected reaction monitoring mode. After 21 days of storage, no significant difference in the recoveries was observed compared to day 0 for pharmaceutical products, while for pesticides, significant losses occurred for DIA and simazine after 10 days (14% and 17% reduction respectively) and a statistically significant decrease in the recovery was noted for cyanazine (78% disappearance). However, the estrogen and progestogen steroids were unstable during storage. The disappearance rates obtained after 21 days of storage vary from 63 to 72% for the feminizing hormones. Overall, pharmaceuticals and pesticides seem to be stable for refrigerated storage for up to about 10 days (except cyanazine) and steroidal hormones can be quite sensitive to degradation and should not be stored for more than a few days

Microstructural influence of the thermal behavior of arc deposited TiAlN coatings with high aluminum content

studied as a function of isothermal annealing. Two compositionally similar but structurally differentcoatings were compared, a Ti$_{0.34}$Al$_{0.66}$N$_{0.96}$ coating with a fine-grain structure consisting of a mixture ofcubic (c) and hexagonal (h) phases, and a Ti$_{0.40}$Al$_{0.60}$N$_{0.94}$ coating with a coarse-grain structure of cubicphase. By in situ wide-angle synchrotron x-ray scattering, spinodal decomposition was confirmed in bothcoatings. The increased amount of internal interfaces lowered the decomposition temperature by 50 Cfor the dual-phase coating. During the subsequent isothermal anneal at 1000 C, a transformation from c-AlN to h-AlN took place in both coatings. After 50 min of isothermal annealing, atom probe tomographydetected small amounts of Al (~2 at.%) in the c-TiN rich domains and small amounts of Ti (~1 at.%) in theh-AlN rich domains of the coarse-grained single-phase Ti$_{0.40}$Al$_{0.60}$N$_{0.94}$ coating. Similarly, at the sameconditions, the fine-grained dual-phase Ti$_{0.34}$Al$_{0.66}$N$_{0.96}$ coating exhibits a higher Al content (~5 at.%) inthe c-TiN rich domains and higher Ti content (~15 at.%) in the h-AlN rich domains. The study shows thatthe thermal stability of TiAlN is affected by the microstructure and that it can be used to tune the reactionpathway of decomposition favorably

A Spot Pricing Framework To Enable Pricing And Risk Management Of Inter-Domain Assured Bandwidth Services

In the current bandwidth market, Internet Service Providers (ISPs) provide guaranteed Internet bandwidth within their domains. However, they are incapable of providing such assurances for data crossing their domain boundaries. In this paper, we present a spot pricing scheme for Internet bandwidth contracts within an ISP domain. These models when implemented at access or exchange points of different ISP domains would provide assured bandwidth for interdomain traffic. Each contract will constitute a Quality of Service agreement between a customer and a provider within an ISP domain. By appropriately bundling derivative contracts defined on the intra-domain service contracts, a provider will not only be able to give inter-domain Quality of Service assurance, but will be able to add new services and manage its portfolio of services