We consider the task of filtering the noise from images and other types of inputs which are assumed to be piecewise continuous and piecewise monotone. We show that nonlinear diffusion of the data, a powerful filtering method, is too restrictive for such a case, leading to piecewise constant functions. We claim that the piecewise monotonicity can be enhanced by nonlinear diffusion of first parti...

Based on the local Shannon entropy concept in information theory, a new measure of aromaticity is introduced. This index, which describes the probability of electronic charge distribution between atoms in a given ring, is called Shannon aromaticity (SA). Using B3LYP method and different basis sets (6-31G**, 6-31+G** and 6-311++G**), the SA values of some five-membered heterocycles, C(4)H(4)X, a...

A new formulation of a pose refinement technique using “active” models is described. An error term derived from the detection of image derivatives close to an initial object hypothesis is linearised and solved by least squares. The method is particularly well suited to problems involving external geometrical constraints (such as the ground-plane constraint). We show that the method is able to r...

Four fundamental physical parameters of series of benzene derivatives were studied to ascertain correlations with biological activity. These included octanol/water coefficient, vapor pressure, infrared absorption (out-of-plane C-H vibration), and the pi values. Each physicochemical constant exhibited a partial correlation with biological activity suggesting that each played a role. It was presu...

Multiple recognition by cyclodextrin in a bimolecular reaction, namely bromination of styrene, methyl cinnamate, phenylacetylene and allylbenzene, has been studied. Bromohydrin is obtained as a major product along with dibromide in the bromination of styrene and methyl cinnamate. The percentage of bromohydrin decreases as the cavity size increases. With phenylacetylene, bromophenylacetylene and...

Previous reports have demonstrated that aconitase has a single reactive sulfhydryl at or near the active site (Johnson, P. G., Waheed, A., Jones, L., Glaid, A. J., and Gawron, O. (1977) Biochem. Biophys. Res. Commun. 74, 384-389). On the basis of experiments with phenacyl bromide in which enzyme activity was abolished while substrate afforded protection, it was concluded that this group was an ...

total), and the solution was stirred for 12 h at 25 OC. The reaction mixture was applied to a small column of Dowex 50x8 (H+), and it was eluted with distilled water (2.5 mL). The eluent was neutralized with 10% NaOH (67 pL), a solution of phenacyl bromide (43.4 mg) in acetone (2.5 mL) was added, and the reaction mixture was refluxed for 2 h. The acetone was removed by rotary evaporation, and t...

Condensation and cyclization of 5-hydroxy- 1,2,4- thiadiazol-2-yl hydrazine 1 with pyruvic acid, phenacyl bromide, propargyl bromide and ally1 bromide afforded compounds 2,5,7 3, 4 ,6 and 8 respectively, Reaction of 1 with epichforohydrine afforded 4-hydroxy-N-[5-hydroxy- 1 ,3,4-thiadiazoly1] pyrazolidine 9

A promising imidazole compound was synthesized through the following route. The reaction of 5-methyl-2-phenyl-1H-imidazole-4-carbohydrazide (1) with carbon disulfide and potassium hydroxide in ethanol (80%) afforded salt (2). Refluxing (2) phenacyl bromide (3) ethanol/water (1:1) gave 2-((5-(5-methyl-2-phenyl-1H-imidazol-4-yl)-1,3,4-oxadiazol-2-yl)thio)-1-phenylethan-1-one (4) a 76% yield. stru...