Surface shape estimation from photometric images

One of the most studied techniques for recovering surface shapes using a computer vision system is the photometric. This method is based on the analysis of one or several images of an object illuminated from a known direction . This kind of images can be considered reflectance maps that give us information of the surface gradient. In computer vision, the problem of recovering 3D information from shaded images is considered an inverse problem. To integrate surface gradient information it is proposed a regularization technique that gives a stable solution of the inverse problem and allows the possibility of reducing errors caused by noise. Results applied on synthetic and real experimental images are presented.     

Mécanisme de solvolyse des cis- et trans-(p-toluènesulfonates) d'aryl-2-cyclopentyle I. Etude de la première étape de la solvolyse: effets isotopiques de l' atone de deutérium en position 2, effets de sel basique et effet spécial de sel

Solvolysis Mechanism of cis - and trans-2-Arylcylopentyl p-Toluenesulfonates. The Step: 1-Deuterium Isotope Effects, Basic Salt Effects, and Special Salt Effect We have studied the first step of the solvolysis of cis and trans-2-arylcyclopentyl p-toluenesulfonates in HCOOH, AcOH, and EtOh. All substrates show a high kinetic 1-deuterium isotope effect (k_H/k_D(1) >1.15). This fact indicates that first step leads to classical intimate ion-pair Which dissociates to a solvet-separated ion-pair, without participation either of solvent, the 2-aryl group, or a H-atom at C(2). The slight influence of added basic ions on reaction rate allows us to exclude any direct solvent attack on the covalent substrate even in the most favorable case, i.e. ethanolysis of 2-(p-nitrophenyl)cylopentyl-p-toluenesulfonates. Furthermore, solvent-separated ion pair formation is indicated by the special salt effect induced by LiClO₄.     

Conformational behaviour of the antineoplastic peptide dolastatin-10 and of two mutated derivatives

Summary The three-dimensional structure of dolastatin-10, an extremely potent cytostatic and antineoplastic peptide extracted from the mollusc Dolabella auricularia, has not yet been fully characterized in an experimental way. By means of a systematic conformational search of the natural peptide and of two mutated analogs, carried out both in vacuo and in aqueous solution, the present work allows to obtain insights into the conformational preferences of this remarkable compound. In addition, the ability to form intra- and intermolecular H-bonds as a function both of the sequence and of the conformation is discussed. The search for the best molecular conformations has been carried out using a molecular mechanics approach, based on the CVFF potential. Dolastatin-10 contains some unusual amino acids for which no experimental structural data are available. In order to check the reliability of the CVFF potential in predicting structures of such nonconventional amino acids, geometry optimizations have been carried out using the ab initio Hartree-Fock procedure. The CVFF parameterization is found to be adequate also for nonconventional amino acids.     

Synthesis of a new series of N-substituted-3-[l-alkyl(aryl)- 4-piperidyl]azetidin-2-ones as possible muscarinic agents

A new series of N-substituted-3-[1-alkyl(aryl)-4-piperidyl]azetidin-2-ones 2a-j structurally related to the previously reported 2,7-diazaspiro[3.5]nonan-1-ones 1 have been synthesized and tested for their activity as muscarinic agents, both in vitro and in vivo. Preliminary pharmacological results showed that compounds 2 are devoid of significant cholinergic properties.