Quitooligosacáridos bifuncionales: relación entre características químico-físicas y propiedades biológicas

As the degraded products of chitosan, chitooligosaccharides (COS) have recently been produced by several methods, such as enzymatic an acidic hydrolysis. Chitosans are a family of biocompatible and biodegradable biopolymers obtained by N-deacetylation of chitin, the most abundant natural polymer after cellulose, consisting of two monomeric units, N-acetyl-2- amino-2-deoxi-D-glucose (A units) and 2-amino-2-deoxi-D-glucose (D units) linked by β (1→4) links. The degraded products COS, have a smaller molecular weight and therefore have better solubility and lower viscosity under physiological conditions because of shorter chain lengths and free amino groups in D-glucosamine units. The study of COS has been increasing not only because they come from a natural source, but also because of their biological compatibility and effectiveness. There are numerous reports on the biological activities of COS and their potential applications in food industry, pharmacy, agricultural or biomedicine. Nevertheless, in these studies it is difficult to find well defined COS in terms of physicochemical parametres, because these samples are usually poorly characterized. This makes it difficult to compare the results and to understand their mecanism of action. Degradation of the O-glycosidic linkages of chitosan by different methods, results in COS with different numbers and sequences of A and D units as well as different degrees of polymerisation (DP). Over the past few years, several technological approaches have been taken in preparing COS, including acid hydrolysis or enzymatic methods, among others. Therefore, in order to obtain COS with different physicochemical properties, different preparation methods of COS have been developed in this work. Then, the study of the relationship between physicochemical properties of these COS and their biological activities such as natural antioxidants, antibacterial agents, mucoadhesive and anti-inflammatory effects have been studied...

Measuring the impact of international R&D cooperation: the case of Spanish firms participating in the EU Framework Programme

The objective of this paper is to analyse the effects of international R&D cooperation on firms’ economic performance. Our approach, based on a complete data set with information about Spanish participants in research joint ventures supported by the EU Framework Programme during the period 1995-2005, establishes a recursive model structure to capture the relationship between R&D cooperation, knowledge generation and economic results, which are measured by labour productivity. In the analysis we take into account that the participation in this specific type of cooperative projects implies a selection process that includes both the self-selection by participants to join the consortia and the selection of projects by the European Commission to award the public aid. Empirical analysis has confirmed that: (1) R&D co-operation has a positive impact on the technological capacity of firms, captured through intan-gible fixed assets and (2) the technological capacity of firms is positively related to their productivity.

Établissement d'une lignée cellulaire pro-érythroïde de souris : outil d'étude de la régulation transcriptionnelle des gènes de globine

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Caractérisation des interactions d'inhibiteurs de l'entrée du VIH dans un modèle de cellules dendritiques in vitro

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Étude du mécanisme de décalage de phase de lecture en-1 du virus de l'immunodéficience humaine de type 1 et de son importance dans la réplication du virus

Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal.

Mécanismes d'inhibition de l'apoptose par la procaspase-2S : effet sur la formation des corps apoptotiques

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Établissement d'une lignée cellulaire pro-érythroïde de souris : outil d'étude de la régulation transcriptionnelle des gènes de globine

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Caractérisation des interactions d'inhibiteurs de l'entrée du VIH dans un modèle de cellules dendritiques in vitro

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Étude du mécanisme de décalage de phase de lecture en-1 du virus de l'immunodéficience humaine de type 1 et de son importance dans la réplication du virus

Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal.

Mécanismes d'inhibition de l'apoptose par la procaspase-2S : effet sur la formation des corps apoptotiques

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Age determination of sediment core GIK16523-1

High-resolution studies of a planktonic foraminifer core record from the South China Sea (SCS) (31KL: 18°45.4'N, 115°52.4'E, water depth 3360 m) reveal changes driven by ice-volume forcings in the climate of the East Asian monsoon in the western Pacific marginal sea during the late Quaternary. The analyses of planktonic foraminifer faunal abundance data from the core indicate significant variations in the relative abundances of the dominant taxa over the past 100,000 years since the isotope stage 5. The transfer function estimates of faunal sea surface temperatures (SST) correlate well with a long-term (104-105 years) trend of global glaciation. About 65,000 years ago, there was an observable change in the mode of SST variability as many low-latitude records have shown. These findings suggest that the SCS surface circulation and the East Asian winter monsoon systems are mainly driven by variations in global glaciation levels. The association of surface ocean cooling in the SCS with global climatic events suggests that fluctuations in the strength of the East Asian winter monsoon may be linked to shifts in the latitudinal position of the westerly winds and the Siberian high-pressure system.

Analytical results of 19 amino acid analyses from Unit 3.1 of sediment core CRP-1 (Table 1)

Amino acid-based geochronological analyses were carried out on fossil mollusc shell and foraminifera from Unit 3.1, Cape Roberts Project core CRP-1. Ratios of D-alloIsoleucine to L-Isoleucine (D/L) were measured from 19 fossil samples using cation exchange High Performance Liquid Chromatography (HPLC) methods. Preliminary interpretation of these results suggest that Unit 3.1 contains carbonate fossils having multiple ages. The interpreted ages have a bimodal distribution between ~220 Ka (Quaternary) and ~2.4 Ma (Pliocene). However, these results lack a comprehensive regional and taxonomic context for amino acid studies in Antarctica and therefore should be regarded as preliminary age estimates of fossil shell ages.

Ruthenibacterium lactatiformans gen. nov., sp.nov., an anaerobic, lactate-producing member of the family Ruminococcaceae isolated from human faeces

Two novel strains of Gram-stain-negative, rod-shaped, obligately anaerobic, non-spore-forming, non-motile bacteria were isolated from the faeces of healthy human subjects. The strains, designated as 585-1T and 668, were characterized by mesophilic fermentative metabolism, production of d-lactic acid, succinic acid and acetic acid as end products of d-glucose fermentation, prevalence of C18 : 1 ω9, C18 : 1 ω9 aldehyde, C16 : 0 and C16 : 1 ω7c fatty acids, presence of glycine, glutamic acid, lysine, alanine and aspartic acid in the petidoglycan peptide moiety and lack of respiratory quinones. Whole genome sequencing revealed the DNA G+C content was 56.4–56.6 mol%. The complete 16S rRNA gene sequences of the two strains shared 91.7/91.6 % similarity with Anaerofilum pentosovorans FaeT, 91.3/91.2 % with Gemmiger formicilis ATCC 27749T and 88.9/88.8 % with Faecalibacterium prausnitzii ATCC 27768T. On the basis of chemotaxonomic and genomic properties it was concluded that the strains represent a novel species in a new genus within the family Ruminococcaceae , for which the name Ruthenibacterium lactatiformans gen. nov., sp. nov. is proposed. The type strain of Ruthenibacterium lactatiformans is 585-1T (=DSM 100348T=VKM B-2901T).

Solubility and solvation of monosaccharides in ionic liquids

Herein, solubility experimental data for six monosaccharides, viz. D-(+)-glucose, D-(+)-mannose, D-(-)-fructose, D-(+)-galactose, D-(+)-xylose and L-(+)-arabinose, in four ionic liquids (ILs), at temperatures ranging from 288.2 to 348.2 K, were obtained aimed at gathering a better understanding of their solvation ability and molecular-level mechanisms which rule the dissolution process. To ascertain the chemical features that enhance the solubility of monosaccharides, ILs composed of dialkylimidazolium or tetra-alkylphosphonium cations combined with the dicyanamide, dimethylphosphate or chloride anions were investigated. It was found that the ranking of the solubility of monosaccharides depends on the IL; yet, D-(+)-xylose is always the most soluble while D-(-)-fructose is the least soluble monosaccharide. The results obtained show that both the IL cation and the anion play a major role in the solubility of monosaccharides. Finally, from the determination of the respective thermodynamic properties of solution, it was found that enthalpic contributions are dominant in the solubilization process. However, the observed differences in the solubilities of monosaccharides in 1-butyl-3-methylimidazolium dicyanamide are ruled by a change in the entropy of solution.

INST-D 2016. 6 [Videos de divulgación de resultados de la ejecución de acciones de fortalecimiento de la actividad artesanal en el departamento de Atlántico]

8 vídeos, duración promedio de c/u 3' 40"