Emilio Rodríguez

Reformulation of queries using similarity thesauri

One of the major problems in information retrieval is the formulation of queries on the part of the user. This entails specifying a set of words or terms that express their informational need. However, it is well-known that two people can assign different terms to refer to the same concepts. The techniques that attempt to reduce this problem as much as possible generally start from a first search, and then study how the initial query can be modified to obtain better results. In general, the construction of the new query involves expanding the terms of the initial query and recalculating the importance of each term in the expanded query. Depending on the technique used to formulate the new query several strategies are distinguished. These strategies are based on the idea that if two terms are similar (with respect to any criterion), the documents in which both terms appear frequently will also be related. The technique we used in this study is known as query expansion using similarity thesauri.

Structural characterization and cytostatic activity of chlorobischolylglycinatogold(III).

Based on the ability of bile acids for vectorializing the cytostatic activity of other agents, we have designed and synthesized a new bile acid cholylglycinato Au(III) complex, named Bamet-A1. It has been characterized by means of EA (elemental analysis), FT-IR, NMR, FAB-MS (fast atom bombardment-mass spectrometry) and Vis-UV techniques. This characterization allowed us to propose a structure of the type [Au CG(O) CG(N,O) Cl] for the neutral complex, which has the composition C522H84N2O12AuCl and is very soluble in water, methanol, ethanol and DMSO (dimethylsulfoxide). The study in aqueous solution suggested a redox process for its transformation, which is accompanied by the appearance of colloidal gold phase. The behavior in 4 mM NaCl water (in order to mimic the cytoplasmatic fluid) was similar to that observed in water, while in a 150 mM NaCl (similar to extracellular fluid and serum), the apparition of a dark blue precipitate was observed. This complex displays fluorescence, which does not change when incubated with DNA obtained from E. coli. Bamet-A1 was found to inhibit the growth of a variety of cell lines. The cytostatic effect was mild against human hepatoma HepG2, mouse hepatoma Hepa 1-6, rat hepatoma McA RH-7777 and human colon adenocarcinoma LS-174T, and stronger against mouse sarcoma S180-II and mouse leukemia L-1210 cells. The appearance of colloidal Au during the process of hydrolysis under physiological conditions may explains the low cytostatic activity.

Experiments in Term Expansion Using Thesauri in Spanish

This paper presents some experiments carried out this year in the Spanish monolingual task at CLEF2002. The objective is to continue our research on term expansion. Last year we presented results regarding stemming. Now, our effort is centred on term expansion using thesauri. Many words that derive from the same stem have a close semantic content. However other words with very different stems also have semantically close senses. In this case, the analysis of the relationships between words in a document collection can be used to construct a thesaurus of related terms. The thesaurus can then be used to expand a term with the best related terms. This paper describes some experiments carried out to study term expansion using association and similarity thesauri.

Preparation and characterization of a copper(II) compound with a new glycine Schiff base containing an ester function

SummaryA new Schiff base was obtained from glycine and ethyl-α-ketocyclopentylcarboxylate. This forms a potassium salt K(Rgly)·H2O, where Rgly=C10H14O4N. From this salt a new copper(II) complex was prepared, Cu(Rgly′)·2H2O, where Rgly′=C10H13O4N (deprotonated Schiff base). The compounds were characterized by i.r. spectroscopy, differential thermal analysis (d.t.a.) and thermogravimetric analysis (t.g.). The activation energy corresponding to the dehydration process for compounds was determined. On the basis of spectral data, the copper compound is believed to be pentacoordinate and square pyramidal.

Preparation and characterization of tetrachlorocobaltates of α,ω-alkanediammonium

Several tetrachlorocobaltates(II) of diprotonated α,ω-alkanediamines have been prepared using the following aliphatic diamines: NH2(CH2)nNH2, where n=2,3,5,6,7,8,9 and 10. Analytical results show that the compounds prepared correspond to the empirical formula (AAH2) [CoCl4], where AAH22+ is the doprotonated diamine. The formula for the compound with ethylenediamine is, however, (enH2)2CoCl6. Magnetic moments and electronic spectra confirm the existence of CoCl42− in all compounds.

Some Lanthanide Complexes of a Glycine Derivative Containing an Ester Function

Abstract Lanthanide complexes: Ln(Rgly)2OH2 H2O (where Ln = La-Ho and Y: Rgly = C10H14O4N) have been prepared by the reaction of the corresponding lanthanide chloride and the ligand N-(2-ethoxycarbonyl-l-cyclopent-en-yl)-glycinate (Rgly). The complexes were characterized by elemental analysis, electrical conductance. magnetic susceptibility, IR and UV-visible spectra and thermal analysis.

Preparation and thermal study of the potassium, magnesium, calcium and barium compounds with an l-alanine derivative containing an ester function

Abstract The compounds K(Rala)·H 2 O and M(Rala) 2 · n H 2 O (M = Mg, n = 4; M = Ca and Ba, n = 2; Rala = C 11 H 16 NO 4 − ), obtained by condensation reaction between ethyl-α-ketocyclopentylcarboxylate (C 8 H 12 O 3 ) and the L-alanine in the presence of the metallic salt, have been prepared and studied. The compounds are characterized by elemental analysis, by IR, UV and mass spectroscopy, NMR and thermal analysis (TG, DTA and DSC).

Preparation and thermal study of the magnesium, calcium and barium compounds with a glycine Schiff base containing an ester function

Abstract The compounds N[Rgly]2·nH2O (M = Mg and Ca, n = 4; M = Ba, n = 2; Rgly− = C10H14NO4−), obtained by the condensation reaction between ethyl-α-ketocyclopentylcarboxylate and glycine in the presence of the metallic salt, were prepared and studied. The compounds were characterized by IR and UV spectroscopy, differential thermal analysis and thermogravimetric analysis.

Stabilization of Nickel(II) Chlorocomplexes with α,ω-Alkanediammonium Cations

Abstract The following nickel(II) chlorocomplexes stabilized with α,ω alkanediammonium cations were prepared: NiCl2·2bnH2Cl2·5H2O (1), 2NiCl2·2pnH2Cl2·4H2O (2), 2NiCl2·hnH2Cl2·4H2O (3), 2NiCl2·2hpH2Cl2·4H2O (4), where bn = 1,4-butanediamine, pn = 1,5-pentanediamine, hn = 1,6-xanediamine and hp = 1,7-heptanediamine. The solid state electronic spectra and magnetic moments show that nickel (II) is octahedral in all the compounds. The complex anion can be formulated as [Ni2Cl6(H2O)4]2− for compound (3), [Ni2Cl8(H2O)2]4- for compounds (2) and (4) and [NiCl4(H2O)2]2- for compound (1). By loss of water molecules the corresponding anhydrous compounds are produced; these apparently contain the dimer species with pentacoordinated nickel [Ni2Cl8]4-. The anhydrous compound obtained from (3) contains the polymeric species with hexacoordinated nickel [NiCl3]n- n.

Stabilization of cobalt(II) chloro-complexes with the butanediammonium cation

SummaryCobalt(II) chlorocomplexes with empirical formulae (bnH2)2CoCl6·2H2O (1) and (bnH2)2CoCl6 (2), where bnH22+ represents the diprotonated species of putrescine (1,4-butanediamine), were prepared.The visible spectra in the solid state and measurement of the magnetic moments permit the assignation of an octahedral geometry for cobalt in (1) and a tetrahedral geometry for (2).