José Manuel Gómez Soriano

A passage retrieval system for multilingual question answering

In this paper we present a new method to improve the coverage of Passage Retrieval (PR) systems when these systems are employed for the Question Answering (QA) tasks. The ranking of passages obtained by the PR system is rearranged to emphasize those passages with more probability to contain the answer. The new ranking is based on finding the n-gram structures of the question that are presented in the passage, and the weight of the passages increases when they contain longer n-grams structures of the question. The results we present show that the application of this method improves notably the coverage of the classical PR system based on the Space Vectorial Model.

A new polymer-supported reagent for the Fmoc-protection of amino acids

A new polymer-supported Fmoc-OSu (Fmoc-P-OSu) has been prepared from polymer-bound N-hydroxysuccinimide (P-HOSu), and used as a solid-supported reagent for the Fmoc-protection of amino groups. The residual P-HOSu generated after the protection reaction can be separated by simple filtration and reused.

Polymer-bound TBTU as a new solid-supported reagent for peptide synthesis

Abstract A new polymer-supported TBTU (P-TBTU) has been prepared from polystyrene-bound 1-hydroxybenzotriazole (P-HOBT) and used efficiently as a solid-supported reagent for peptide-coupling reactions, and is even effective with wet solvents. The P-HOBT can be recovered by simple filtration and reused for the preparation of new P-TBTU.

2,7-Di-tert-butyl-Fmoc-P-OSu: a new polymer-supported reagent for the protection of the amino group.

The polymer-supported (2,7-di-tert-butyl-9-fluorenyl)methyl succinimidyl carbonate (Dtb-Fmoc-P-OSu), derived from (2,7-di-tert-butyl-9-fluorenyl)methyl chloroformate (Fmoc-Cl) and a polymeric N-hydroxysuccinimide (P-HOSu), has been used for the preparation of Dtb-Fmoc-protected amines and amino acids. After the N-protection reaction, the liberated P-HOSu can be recovered and reused. This Dtb-Fmoc-protection improves the solubility of the Fmoc-protected analogues.

Polymer-bound N-hydroxysuccinimide as a solid-supported additive for DCC-mediated peptide synthesis

The use of 1,3-dicyclohexylcarbodiimide (DCC) in the presence of N-hydroxysuccinimide (HOSu) or other HOX compounds as racemization-reducing additives is a classical method for peptide bond formation, which involves the formation of active esters, 1 derivative 1 being an example of one of them prepared from HOSu. These activated species usually subsequently undergo smooth coupling reactions with amines for the forma- tion of amide bonds, and have been widely used in both solution and solid-phase peptide synthesis. 2 Isolated HOSu-derived active esters have been employed, for instance, for the preparation of leucyldemethylblasti- cidin S as part of a study of self-resistance mechanisms of Streptomyces bacteria, 3 or for the synthesis of a novel family of hairpin cyclic peptides. 4 In addition, they have been used in the final step of the synthesis of the immunomodulator galactosylceramide AGL-537, 5

Ammonium salts from polymer-bound N-hydroxysuccinimide as solid-supported reagents for EDC-mediated amidations

Abstract New ammonium and alkylammonium salts derived from a polymeric N -hydroxysuccinimide (P-HOSu) have been prepared and used for the amidation of carboxylic acids and amino acids mediated by 1-ethyl-3-(3′-dimethylamino-propyl)carbodiimide hydrochloride (EDC). These polymer-supported ammonium salts afforded the corresponding amides in good yield, without detectable α-racemization and with easy recovery of the P-HOSu after the amidation reaction, being especially suitable for the amidation of Fmoc-protected amino acids.

Adapting the JIRS Passage Retrieval System to the Arabic Language

The need of having a Passage Retrieval (PR) system for Arabic texts is due essentially to our aim to build an Arabic Question Answering (QA) system in our research team. We have chosen working on the PR system to be our first step to pursue our aim because being the core component and its quality will affect directly the performance of the QA system. JAVA Information Retrieval System (JIRS) is a PR QA-oriented system, multi-platform, open source and free to use. JIRS uses an n-gram model and it is language-independent. It separates language configuration files to make easier its adaptation to any language. In this paper, we report the different challenges when adapting the JIRS to the Arabic language.In order to evaluate JIRS on Arabic, we had to develop an Arabic test-bed using the multilingual CLEF QA one as guideline. We also report the results obtained in our experiments where we retrieved Arabic passages with JIRS first without any text preprocessing and second performing a prior light-stemming on the documents of the test-bed. The preliminary results show that it is possible to obtain a first Arabic passage retrieval system adapting JIRS on pre-processed text with a light-stemmer.