Harmful Elements in Estuarine and Coastal Systems

Estuaries and coastal zones are dynamic transitional systems which provide many economic and ecological benefits to humans, but also are an ideal habitat for other organisms as well. These areas are becoming contaminated by various anthropogenic activities due to a quick economic growth and urbanization. This chapter explores the sources, chemical speciation, sediment accumulation and removal mechanisms of the harmful elements in estuarine and coastal seawaters. It also describes the effects of toxic elements on aquatic flora and fauna. Finally, the toxic element pollution of the Venice Lagoon, a transitional water body located in the northeastern part of Italy, is discussed as a case study, by presenting the procedures adopted to measure the extent of the pollution, the impacts on organisms and the restoration activities

The Homoconjugated Electron-Releasing Carbonyl Group of 1-Methylbicyclo[2.2.1]Hept-5-En-2-One - Regioselective Syntheses of 5-Chloro-1-Methylbicyclo[2.2.1]Hept-5-En-2-One and 6-Chloro-1-Methylbicyclo[2.2.1]Hept-5-En-2-One

Syntheses of (+/-)-2-exo-cyano-1-methyl-7-oxabicyclo[2.2.1]hept-5-en-2-endo-yl acetate (1) and of (+/-)-1-methyl-7-oxabicyclo[2.2.1]hept-5-en-2-one (2) are reported. The additon of PhSeCl to 1 afforded (+/-)-5-endo-chloro-2-exo-cyano-1-methyl-6-exo-(phenylselenenyl)-7-oxabi cyclo[2.2.1]hept-2-endo-yl acetate (6), whereas 2 added to PhSeCl with the opposite regioselectivity giving (+/-)-6-endo-chloro-1-methyl-5-exo-(phenylselenenyl)-7-oxabicyclo[2.2.1] heptan-2-one (7). These adducts were converted into 5-chloro-1-methyl-7-oxabicyclo[2.2.1]hept-5-en-2-one (9) and 6-chloro-1-methyl-7-oxabicyclo[2.2.1]hept-5-en-2-one (10), respectively

Total Asymmetric-Synthesis of Polypropionate Fragments and Doubly Branched Heptono-1,4-Lactones

2-Cyano-1,5-dimethyl-7-oxabicyclo[2.2.1]hept-5-en-2-yl (1'R)-camphanate ((+)-3)and (+)-(1R,4R)-1,5-dimethyl-7-oxabicyclo[2.2.1]hept-5-en-2-one ((+)-4) were obtained readily from 3,4-dimethylfuran. (+)-3 was converted into 2,7-dideoxy-2,4-di-C-methyl-L-glycero- and D-glycero-L-altro-heptono-1,4-lactone ((+)-17) and ((+)-18)

Lithostratigraphy and Chemostratigraphy of salt diapir sedimentary inclusions: unraveling Ediacaran salt tectonics in the Flinders Ranges, South Australia

Rachelle Kernen, Asmara Lehrmann and Piper Po

Covalent immobilization of native biomolecules onto Au(111) via N-hydroxysuccinimide ester functionalized self-assembled monolayers for scanning probe microscopy.

We have worked out a procedure for covalent binding of native biomacromolecules on flat gold surfaces for scanning probe microscopy in aqueous buffer solutions and for other nanotechnological applications, such as the direct measurement of interaction forces between immobilized macromolecules, of their elastomechanical properties, etc. It is based on the covalent immobilization of amino group-containing biomolecules (e.g., proteins, phospholipids) onto atomically flat gold surfaces via omega-functionalized self-assembled monolayers. We present the synthesis of the parent compound, dithio-bis(succinimidylundecanoate) (DSU), and a detailed study of the chemical and physical properties of the monolayer it forms spontaneously on Au(111). Scanning tunneling microscopy and atomic force microscopy (AFM) revealed a monolayer arrangement with the well-known depressions that are known to stem from an etch process during the self-assembly. The total density of the omega-N-hydroxysuccinimidyl groups on atomically flat gold was 585 pmol/cm(2), as determined by chemisorption of (14)C-labeled DSU. This corresponded to approximately 75% of the maximum density of the omega-unsubstituted alkanethiol. Measurements of the kinetics of monolayer formation showed a very fast initial phase, with total coverage within 30 S. A subsequent slower rearrangement of the chemisorbed molecules, as indicated by AFM, led to a decrease in the number of monolayer depressions in approximately 60 min. The rate of hydrolysis of the omega-N-hydroxysuccinimide groups at the monolayer/water interface was found to be very slow, even at moderately alkaline pH values. Furthermore, the binding of low-molecular-weight amines and of a model protein was investigated in detail