Words recognition using associative memory Navoni, L.; Canegallo, R.; Chinosi, M. ...
Proceedings of the Fourth International Conference on Document Analysis and Recognition,
1997, Letnik:
1
Conference Proceeding
Introduces the application of an analog associative memory chip to word recognition, which is a fundamental topic of the text recognition process. The word recognition method takes advantage of a ...statistical evaluation of the behavior of the optical character recognition system preceding it. That statistical information leads to the creation of a coding that is used to store a lexicon of the most used words in the chip. An input pattern is matched against the full database of the associative memory, and a set of closest patterns is returned. The precision reached by this operation ranges from 93% to 99%. These encouraging results demonstrate the general aptitude of the chip to solve classes of problems that need to use an associative memory.
Although bombesin (BN) and substance P share only the C-terminal dipeptide amide, some substance P receptor antagonists are also weak bombesin receptor antagonists. In order to increase the ...selectivity of the antagonism for the BN receptor, a series of hybrid peptides were synthesized by the solid-phase methodology, and screened on 3T3 fibroblasts for binding and mitogenic activity. The analogues inhibiting BN-induced thymidine incorporation were further tested for peripheral (amylase release and urinary bladder contraction) and central activity (grooming behaviour).
Bombesin is a 14-residue peptide hormone which serves a variety of biological functions, including cell growth control in Swiss 3T3 cultured fibroblasts. It has been also involved in an autocrine ...system regulating the growth of small cell lung carcinoma. A series of bombesin analogues were developed by amino acid deletion, inversion or substitution in the carboxy-terminal region, identified by the target cell receptor. Their properties were examined for: i) competitive binding assays; ii) mitogenic induction and inhibition assays; iii) effects on early cellular events (inositol phosphates production and protein tyrosine phosphorylation). Inversion of the Trp residue, or deletion of the C-terminal tripeptide amide, induced complete loss of receptor affinity and biological effects. Deletion of the His residue, or its derivatization as His (Dnp) in conjunction with Met deletion or modification, gave rise to compounds with reduced receptor affinity and weak antagonistic properties. Other modifications in the C-terminal tripeptide affected the potency but not the biological profile of the parent peptide. These results indicate the basis for the eventual design of improved, specific bombesin receptor antagonists and stimulate further studies on their possible application in the therapy of human small cell lung cancer.
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