GreekLex 2: a comprehensive lexical database with part-of-speech, syllabic, phonological, and stress information

Databases containing lexical properties on any given orthography are crucial for psycholinguistic research. In the last ten years, a number of lexical databases have been developed for Greek. However, these lack important part-of-speech information. Furthermore, the need for alternative procedures for calculating syllabic measurements and stress information, as well as combination of several metrics to investigate linguistic properties of the Greek language are highlighted. To address these issues, we present a new extensive lexical database of Modern Greek (GreekLex 2) with part-of-speech information for each word and accurate syllabification and orthographic information predictive of stress, as well as several measurements of word similarity and phonetic information. The addition of detailed statistical information about Greek part-of-speech, syllabification, and stress neighbourhood allowed novel analyses of stress distribution within different grammatical categories and syllabic lengths to be carried out. Results showed that the statistical preponderance of stress position on the pre-final syllable that is reported for Greek language is dependent upon grammatical category. Additionally, analyses showed that a proportion higher than 90% of the tokens in the database would be stressed correctly solely by relying on stress neighbourhood information. The database and the scripts for orthographic and phonological syllabification as well as phonetic transcription are available at http://www.psychology.nottingham.ac.uk/greeklex/

Basic quantitative characteristics of the Modern Greek language using the Hellenic National Corpus

Modern Greek is one of the least quantitatively studied modern European languages and the goal of this paper is to fill this relative void. We use the Hellenic National Corpus (HNC), which is a growing corpus that currently includes 33 million words. The corpus and all the tools used in our work were developed by the Institute for Language and Speech Processing (ILSP). In this paper we focus on three main areas: the lists of the 1000 most common words and lemmas, word length and letter frequency. We also make some comparisons with earlier work, in which we had used the previous 13 million word edition of the HNC. © Taylor & Francis Group Ltd

Conformational analysis of C-disaccharides using molecular mechanics calculations

Relaxed-residue energy maps based on the MM3 force field were computed for the methyl glycosides of eight C-linked D-glucosyl disaccharides: the two-bond axial-equatorial linked disaccharides β-kojibioside [(1→2)α-], β-nigeroside [(1→3)α-] and β-maltose [(1→4)α-], the two-bond equatorial-equatorial linked disaccharides β-sophoroside [(1→2)β-], β-laminarabioside [(1→3)β-], β-cellobioside [(1→4)β-] and the three-bond-linked (1→6) disacharides C-isomaltoside and C-gentiobioside. Optimized structures were calculated on a 20° grid spacing of the torsional angles about the C-glycosidic bonds and the final isoenergy surfaces were based on 11664 conformations, for the two-bond-linked disaccharides and 69984 conformations for the three-bond-linked disaccharides. Boltzmann-weighted 3J coupling constants were calculated and compared to the experimental values. They are satisfactory except for maltose where hydrogen bonds cause an over-estimation of the energy differences between the conformers. The energy maps are similar to maps of the corresponding O-disaccharides, but there are differences in the locations and the relative energies of the minima. The preferred conformations of the C-glycosidic bonds are as if they were conforming to the exo-anomeric effect but are closer to staggered conformations than shown by the MM3 results for the O-linkages

Improving machine translation output of german compound and multiword financial terms

The present application translates German financial terms to the Greek language aiming to maximize the translation quality. The demand for better translation increases the need for more MT systems, journalists or professionals in the banking sector require accurate translations. A novel statistical method of MT is presented, where we use a probability distribution over sentence pairs from a parallel corpus (German-Greek). Both the MT System and the parallel corpus was built from scratch. The present application combines parameters in a new way and estimates the probabilities that extract the best translation. © Springer Nature Switzerland AG 2020

Stereoselective intramolecular azide 1,3-dipolar cycloaddition

Ethyl (E)-7-azido-6-[bis(tert-butoxycarbonyl)amino]-2-heptenoate undergoes a stereoselective intramolecular azide 1,3-dipolar cycloaddition leading to a stable triazoline. The configuration and the conformation of the triazoline obtained were determined by spectroscopic data and confirmed by molecular mechanics calculations

Conformational Analysis of C-Trehaloses Using Molecular Mechanics Calculations

Relaxed-residue energy maps based on the MM3 force field were computed for the three C-linked (1-1) D-glucosyl disaccharides, C-trehaloses: the axial-axial linked α,α-trehalose, the axial-equatorial α,β-trehalose and the equatorial-equatorial linked β,β-trehalose. Optimized structures were calculated on a 20°-grid spacing of the torsional angles about the C-glycosidic bonds. Boltzman weighted 3J coupling constants were calculated and compared to the experimental values; they are satisfactory. The general shape of the energy maps indicates that α,α-trehalose is a quite rigid molecule adopting only one conformation around the C-glycosidic linkage, whereas the other two isomers are rather flexible. Compared to the corresponding O-disaccharides α,β-and β,β-trehaloses exhibit a larger number of low energy conformers and a larger area of the map energy < 8 kcal/mol. The preferred conformations of the axial C-glycosidic bond are in agreement with the exo-anomeric effect. Equatorial C- glycosidic bonds are rather flexible, influenced by the polarity of the milieu and the formation of interresidue hydrogen bonds

Conformational analysis of C-disaccharides using molecular mechanics calculations

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Conformational properties of the macrocyclic trichothecene mycotoxin verrucarin A in solution

Phase-sensitive nuclear Overhauser enhancement spectroscopy (NOESY) experiments, 3J couplings and computational molecular modeling (MM2* and MMFF force fields) were employed to examine the conformational properties of verrucarin A in chloroform solutions. The MMFF force field calculations resulted in a family of 12 low-energy structures along with their populations, the latter being determined by the NMR analysis of molecular flexibility in solution(NAMFIS) deconvolution analysis. The concluded model was capable of reproducing successfully the experimental NOESY cross-peak volumes and the proton-coupling constants. Among the 12 conformers, the one which was similar to the structure of verrucarin A in the solid state was the predominant accounting for 75% of the total relative population, although other low-energy conformations contributed to a lesser degree in order to explain the experimental data. Copyright © 2008 John Wiley & Sons, Ltd

Conformational analysis of C-trehaloses using molecular mechanics calculations

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