Water level fluctuations in a coastal lagoon: El Yali Ramsar wetland, Chile

El Yali coastal reserve is the most important wetland complex in Mediterranean climate central Chile, especially due to the native and foreign bird fauna which arrives here periodically. The coastal lagoon, part of a microtidal estuary (1.2m tidal range), is a shallow (< 1m depth) dynamic system and unique site of coexistence of northern halophyte and southern palustrian riparian vegetation. This study identifies and quantifies the effect of forcing variables in the lagoon water level over 1 year of data collection. Transects of piezometers with level sensors were installed between the coastal lagoon and the sea. Monthly water quality data were collected. During the winter rainy season, the lagoon connects with the sea via an ephemeral tidal inlet, producing noticeable daily variations in the water level, up to 80-cm depending on the tides. In contrast, during the season when bar closure of the inlet disconnects the lagoon from the sea, the lagoon level is very stable and only decreases very slowly due to evaporation, which also makes the system hypersaline. During the connection phase, analyses using general pattern, spectral and Fourier analysis of the sea-vs. lagoon-level signals show that two temporal scale hierarchies are relevant: monthly (due to moon cycles) and daily (due to tidal cycles every 12.5 and 24.2-h). A simple diffusion numerical model simulated the water table trends well for the sand bar between the lagoon and the sea, supporting the main effect of the sea level on the lagoon water levels

Unimolecular ion dissociation and laser-induced coalescence of hydrogenated fullerenes

The ion-fragmentation behaviour of hydrogenated fullerenes has been investigated by tandem mass spectrometry applying sector instrumentation. In addition to the expected loss of hydrogen, unimolecular decay reactions are observed featuring cage rupture by the loss of hydrocarbon moieties. The findings are discussed in comparison with the behaviour of other fullerene derivatives. The gas-phase coalescence reactivity of C60H36 has been studied utilising laser desorption/ionization time-of-flight mass spectrometry. In contrast to pure fullerenes and certain organic fullerene derivatives, hydrogenated fullerenes do not readily undergo laser-induced fusion reactions

An artificial estrogen receptor through combinatorial imprinting

Polymeric sorbents targeting endocrine-disrupting estrogen active compounds (EAC) were prepared by terpolymer imprinting using 17b-estradiol (E2) as template. From a group of eight functional monomers representing Brønsted acids, bases, hydrogenbond donors and acceptors, as well as p-interacting monomers, a terpolymer library that comprises all possible binary combinations of the functional monomers was prepared. Binding tests revealed that imprinted polymers exhibit a markedly higher affinity for E2 compared to nonimprinted polymers (NIPs) or polymers prepared by using single functional monomers. A combination of methacrylic acid (MAA) and p-vinylbenzoic acid offered a particularly promising lead polymer, displaying an imprinting factor of 17 versus 2.4 for a benchmark polymer prepared by using only MAA as functional monomer. The saturation capacities ascribed to imprinted sites were four to five times higher for this polymer compared to previously reported imprinted polymers. NMR titrations and moleculardynamics simulations corroborated these results, indicating an orthogonal preference of the two functional monomers with respect to the E2 3-OH and 17-OH groups. The optimized polymer exhibited a retentivity for EACs that correlates with their inhibitory effect on the natural receptor. By using the optimized molecularly imprinted polymers (MIPs) in a model water-purification system, they were capable of completely removing ppb levels of a small group of EACs from water. This is in contrast to the performance of nonimprinted polymers and well-established sorbents for water purification (e.g., active carbon), which still contained detectable amounts of the compounds after treatment