Studies toward the total synthesis of (+)-providencin (1), a highly oxygenated cembranoid dipterpene with a unique bicyclo[12.2.0]hexadecane skeleton and pronounced biological activity, are described. These studies resulted in the synthesis of advanced intermediates 320 and 332 which contain all of the carbon atoms of 1. In a first generation approach...
Among the myriad of naturally occurring bioactive compounds are the aminocyclopentitol-containing natural products that represent a family of sugar-derived microbial secondary metabolites, such as the antibiotics pactamycin, allosamidin, and trehazolin. Pactamycin, a structurally unique aminocyclitol antibiotic isolated from Streptomyces pactum, consists of a 5-membered ring aminocyclitol (cyclopentitol) unit, two aromatic...
Caspian terns (Hydroprogne caspia) and double-crested cormorants
(Phalacrocorax auritus) nest in large colonies on East Sand Island in the Columbia
River estuary, the largest known colonies for the two species in the world. Both
species of piscivorous colonial waterbirds have been identified as predators with a
significant impact on the...
Effective and consistent communication with your customers is vital and should be approached in a holistic manner driven by customer needs, your marketing strategies, and key characteristics of your operation. This document outlines important principles of marketing communication, illustrated throughout with examples from two small, hypothetical companies. A worksheet is...
Detection systems used to monitor reactor operations are of significant interest as tools for verification of operator declarations. Current reactor site safeguards are limited to visual inspections and intrusive monitoring systems. The recent development of antineutrino detectors may soon allow real-time monitoring from an unobtrusive location. Antineutrinos are produced through...