Natural products provide excellent potential leads for drug development because of their chemical diversity and biological functionality. However, the productivity of discovery of new, pharmacologically active natural products has traditionally been low due to inherent difficulties and costs associated with extract dereplication, i.e., isolation, purification and structure elucidation of indivi...

objective during the last three decades sesquiterpenoid lactones have emerged as one of the largest groups of plant products with over 3000 naturally occurring substances known. the genus artemisia characteristically contains this biologically active type of secondary metabolites. with respect to increasing interest in the cytotoxic, antibiotic, phototoxic and antineoplastic activities of sesqu...

The realization of nuclear magnetic resonance (NMR) as a means to perform useful quantum computations has warranted a detailed discussion regarding the physics and instrumentation underlying the construction of a NMR quantum computer to facilitate the design of a desktop quantum computer. A brief overview of classical mechanics, quantum mechanics, and statistical mechanics is presented with New...

Experimental Section Solvents and reagents were purchased from Merck and used as received. 1,6,7,12Tetrachloroperylene-3,4:9,10-tetracarboxylic acid bisanhydride was obtained from BASF. N,N'-Didodecylperylene-3,4:9,10-tetracarboxylic acid bisimide 2 was synthesized according to the literature. NMR spectra were recorded on a Bruker DRX 400 spectrometer using the proton signal of TMS as internal ...

A simple tuned limiter is described which limits the rf voltage amplitude at the input of the receiver amplifier of a pulsed NMR spectrometer. This device prevents overload of the receiver amplifier during the high-power rf pulse and thereby allows fast recovery of the spectrometer following the pulse. When used with Avantek unit amplifiers at 24 MHz, a recovery time of 2.5 mus is achieved.

Objective During the last three decades sesquiterpenoid lactones have emerged as one of the largest groups of plant products with over 3000 naturally occurring substances known. The genus Artemisia characteristically contains this biologically active type of secondary metabolites. With respect to increasing interest in the cytotoxic, antibiotic, phototoxic and antineoplastic activities of sesq...