Beta-carboline alkaloids from a New Zealand marine bryozoan,Cribricellina cribraria

The crude extract of a New Zealand marine bryozoan Cribricellina cribraria was examined and resulted in the isolation of the previously described, 6-hydroxyharman (1) and the new beta-carboline metabolite, 8-hydroxyharman (2).     

Hydrogenation of

The course of the hydrogenation of [5]- and [6]metacyclophane (1b and 1c) and their thermochemistry is described. Both compounds are hydrogenated rapidly (within 10 s) to furnish the bridgehead olefins 13b and 12c. The accompanying hydrogenation enthalpies are -220 and -141 kJmol(-1), respectively. Strain energies (SE) and olefinic strains (OS) of a number of bridgehead olefins have been evaluated by DFT calculations; it was concluded that 13b belongs to the class of hyperstable olefins which correlates nicely with its reluctance to undergo hydrogenation. By combining experimental hydrogenation enthalpies and DFT calculations, SE of 187 and 121 kJmol(-1) were derived for 1b and 1c.     

Non-destructive characterisation of (Ga,In,Al,As,P)-based ternary multilayer structures using spectroscopic ellipsometry

Spectroscopic ellipsometry has been used to measure compositions and layer thicknesses of two-, three- and four-layer structures consisting of Al_0.2Ga_0.8As/GaAs and In_0.53Ga_0.47As/Al_0.48In_0.52As/InP materials. A simple procedure has been developed to obtain Al_0.48In_0.52As dielectric functions by scaling InP values. Very good agreement has been obtained with destructive techniques.     

On the Structure and Flow Processes in the Capillary Fringe of Phreatic Aquifers

The water distribution in the capillary fringe (CF) reflects the interaction of a strongly wetting fluid in a heterogeneous porous medium. Field profiles of gravimetric water content of the CF for a 30m deep, sandy, phreatic aquifer in Israel are critically analyzed in the context of the possible wetting and drainage processes in these sediments. A highly plausible explanation of the profiles is based on the spatial configuration of the CF surface determined from a model of the movement of water within the porous medium. The structural types of CF that can arise from a number of competing pore-scale displacement mechanisms, in the presence of gravity, are characterized by the model. We differentiate between two generic types of CF structures: a tenuous invasion-percolation type and a compact type. Flow, in response to a horizontal pressure gradient, associated with each structure is analyzed. Our interpretation of the field data supports the compact structure with a spatial variation in the height of the CF surface, above the water table, on the order of 1m. In this compact structure horizontal flow is characterized by stagnant regions in the CF above a critical height h _c and flow only for regions below h _c . The field water content (at h _c ) may be used to predict the onset of lateral water flow in the CF.     

Infrared spectral radiance of hot HF and DF in the Δv = 1 bands region as seen through an atmospheric path

Individual spectral line parameters of the Δv = 1 HF bands at elevated temperatures have been generated. Line by line, layer by layer, spectral radiance and absorptance calculations have been compared with previous experimental results. The HF lines and a recent compilation of infrared atmospheric spectral line parameters have been used to compute the infrared spectral radiance from a hot HF source and a given atmospheric path on a line by line, layer by layer basis.     

Marine natural products

This review covers the literature published in 2005 for marine natural products, with 704 citations (493 for the period January to December 2005) referring to compounds isolated from marine microorganisms and phytoplankton, green algae, brown algae, red algae, sponges, coelenterates, bryozoans, molluscs, tunicates and echinoderms. The emphasis is on new compounds (812 for 2005), together with their relevant biological activities, source organisms and country of origin. Biosynthetic studies, first syntheses, and syntheses that lead to the revision of structures or stereochemistries, have been included.