Segmentation, a new method, for color, gray-scale MR medical images, and aerial images, is proposed. The method is based on gray-scale morphology. Edge detection algorithm includes function edge and marker-controlled watershed segmentation. It features the simple algorithm implemented in MATLAB. The watershed segmentation has been proved to be a powerful and fast technique for both contour detection and region-based segmentation. In principle, watershed segmentation depends on ridges to perform a proper segmentation, a property that is often fulfilled in contour detection where the boundaries of the objects are expressed as ridges. For region-based segmentation, it is possible to convert the edges of the objects into ridges by calculating an edge map of the image. Watershed is normally implemented by region growing, based on a set of markers to avoid oversegmentation.

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In an effort to discover potent antibacterials based on the entropically favored "bioactive conformation" approach, we have designed and synthesized a series of novel tricyclic molecules mimicking the conformationally constrained structure of the oxazolidinone antibacterial, Linezolid 1. The structure 3 obtained by this approach was synthesized and found to be moderately active against a panel of Gram-positive organisms tested. Further introduction of a fluorine atom in the aromatic ring of compound 3 as in Linezolid resulted in some excellent compounds possessing potent antibacterial activity. The thus obtained lead molecule 16 was further fine-tuned by structure-activity relationship studies on the amide functionality leading to a number of novel tricyclic oxazolidinone derivatives. Some particularly interesting compounds include the thioamides 36 and 37, thiocarbamate 41, and thiourea 45. The in vitro activity results of amide homologues of 16 (compounds 25-30) revealed that compounds up to four carbon atoms on the amide nitrogen retain the activity. In general, thioamides and thiocarbamates are more potent when compared to the corresponding amides and carbamates.

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Received J une 10, l!)6S Pronethalol, propranolol,-l-(2-naphlhyl)ethanol, l-isopropylamino-.'i-(3-tolyloxy )-2-propanol, and l-(3,4-dichlorophenyl)-2-isopropylaminoethanoI (DCI) have been resolved. The (-) isomer was in each case the more potent adrenergic /3-receptor antagonist, being twice as potent as the racemate and at least 40 times more potent than the (+) isomer. The absolute configuration (R) has been assigned to the (-)