Quercetin solubilisation in bile salts: A comparison with sodium dodecyl sulphate

AbstractTo understand the bioaccessibility of the flavonoid quercetin we studied its interaction with bile salt micelles. The environmental sensitivity of quercetin’s UV–visible absorption spectrum gave information about quercetin partitioning. Two quercetin absorption peaks gave complementary information: Peak A (240–280nm) on the intermicellar phase and Peak B (340–440nm) on the micellar phase. Thus, by altering pH, we showed that only non-ionised quercetin partitions into micelles. We validated our interpretation by studying quercetin’s interaction with SDS micelles. Pyrene fluorescence and the quercetin UV–visible spectra show that the adsorption site for pyrene and quercetin in bile salt micelles is more hydrophobic than that for SDS micelles. Also, both quercetin and pyrene reported a higher critical micelle concentration for bile salts than for SDS. Our method of using a flavonoid as an intrinsic probe, is generally applicable to other lipophilic bioactives, whenever they have observable environmental dependent properties

The effects of type of discourse and of a second language on comprehension processes : a new linguistic relativism?

A través de este trabajo se examinan diversas cuestiones relacionadas con los procesos de comprensión del discurso escrito y de la adquisición de segundas lenguas como el español, inglés o portugués. El objetivo fundamental de este artículo es tratar de desvelar si el procesamiento que realiza el lector durante la comprensión de un discurso determinado o ante la adquisición de una segunda lengua requiere de una actividad cognitiva diferente a cuando se trata de comprender otro de naturaleza diferente o bajo una lengua diferente. Para ello se analiza por un lado, las diferencias existentes entre diferentes tipos de texto, centrándonos fundamentalmente en el narrativo y el expositivo, analizando sus repercusiones sobre varios niveles de la cognición humana. Por otro, se analizan algunos estudios sobre la adquisición de diferentes segundas lenguas y sus repercusiones sobre su nivel de activación cerebral utilizando la técnica de fMRI. Por último, se plantea hasta qué punto el relativismo lingüístico influye en los procesos de comprensión y de la realización de inferencias y de la adquisición de una segunda lengua.In this paper we address issues related to comprehension processes, and how they can be affected by types of text or written discourse, and by a reader’s first or second language. To this end, we discuss the processing of narrative and expository texts, and their effects on different levels of human cognition. Likewise, we discuss the effects of texts written in different codes, that is, in first and second languages. We propose that differences in text comprehension processes occur as a function of their causal nature and of the inferences that are generated during comprehension. In terms of second language comprehension, modern research applying functional magnetic resonance imaging, or fMRI, with bilinguals is discussed in support of the notion that first language comprehension processes are generally replicated in the second language. Therefore, we focus on comprehension processes, generation of interferences, and the processing of a second language as influenced by linguistic relativism

Caracterização agrônomica de populações locais de azevém na região sul do Brasil.

Made available in DSpace on 2011-06-07T16:18:22Z (GMT). No. of bitstreams: 1 dpma802cr2000.pdf: 314565 bytes, checksum: a08ba4df77c69b477b8cc8fcbd0dccef (MD5) Previous issue date: 2011-02-15201

Arithmetically Cohen-Macaulay Bundles on complete intersection varieties of sufficiently high multidegree

Recently it has been proved that any arithmetically Cohen-Macaulay (ACM) bundle of rank two on a general, smooth hypersurface of degree at least three and dimension at least four is a sum of line bundles. When the dimension of the hypersurface is three, a similar result is true provided the degree of the hypersurface is at least six. We extend these results to complete intersection subvarieties by proving that any ACM bundle of rank two on a general, smooth complete intersection subvariety of sufficiently high multi-degree and dimension at least four splits. We also obtain partial results in the case of threefolds.Comment: 15 page

Impact of B-ring substitution and acylation with hydroxy cinnamic acids on the inhibition of porcine α-amylase by anthocyanin-3-glycosides

An inhibitory effect on alpha-amylase and alpha-glucosidase is postulated for polyphenols. Thus, ingestion of those secondary plant metabolites might reduce postprandial blood glucose level (hyperglycemia), which is a major risk factor for diabetes mellitus type II. In addition to a previous study investigating structure-effect relationships of different phenolic structures, the effect of anthocyanins is studied in detail here, by applying an alpha-amylase activity assay, on the basis of the conversion of 2-chloro-4-nitrophenyl-4-O-ß-galactopyranosyl maltoside (GalG2CNP) and detection of CNP release by UV/Vis spectroscopy and isothermal titration calorimetry (ITC). All anthocyanin-3-glucosides showed a mixed inhibition with a strong competitive proportion, Kic < 134 µM and Kiu < 270 µM; however, the impact of the B-ring substitution was not statistically significant. UV/Vis detection failed to examine the inhibitory effect of acylated cyanidins isolated from black carrot (Daucus carota ssp. Sativus var. Autrorubens Alef.). However, ITC measurements reveal a much stronger inhibitory effect compared to the cyanidin-3-glucoside. Our results support the hypothesis that anthocyanins are effcient alpha-amylase inhibitors and an additional acylation with a cinnamic acid boosts the observed effect. Therefore, an increased consumption of vegetables containing acylated anthocyanin derivatives might help to prevent hyperglycemia

D-brane Categories for Orientifolds -- The Landau-Ginzburg Case

We construct and classify categories of D-branes in orientifolds based on Landau-Ginzburg models and their orbifolds. Consistency of the worldsheet parity action on the matrix factorizations plays the key role. This provides all the requisite data for an orientifold construction after embedding in string theory. One of our main results is a computation of topological field theory correlators on unoriented worldsheets, generalizing the formulas of Vafa and Kapustin-Li for oriented worldsheets, as well as the extension of these results to orbifolds. We also find a doubling of Knoerrer periodicity in the orientifold context.Comment: 45 pages, 6 figure

Characterizing normal crossing hypersurfaces

The objective of this article is to give an effective algebraic characterization of normal crossing hypersurfaces in complex manifolds. It is shown that a hypersurface has normal crossings if and only if it is a free divisor, has a radical Jacobian ideal and a smooth normalization. Using K. Saito's theory of free divisors, also a characterization in terms of logarithmic differential forms and vector fields is found and and finally another one in terms of the logarithmic residue using recent results of M. Granger and M. Schulze.Comment: v2: typos fixed, final version to appear in Math. Ann.; 24 pages, 2 figure

Visualizing metabolic network dynamics through time-series metabolomic data.

BACKGROUND: New technologies have given rise to an abundance of -omics data, particularly metabolomic data. The scale of these data introduces new challenges for the interpretation and extraction of knowledge, requiring the development of innovative computational visualization methodologies. Here, we present GEM-Vis, an original method for the visualization of time-course metabolomic data within the context of metabolic network maps. We demonstrate the utility of the GEM-Vis method by examining previously published data for two cellular systems-the human platelet and erythrocyte under cold storage for use in transfusion medicine. RESULTS: The results comprise two animated videos that allow for new insights into the metabolic state of both cell types. In the case study of the platelet metabolome during storage, the new visualization technique elucidates a nicotinamide accumulation that mirrors that of hypoxanthine and might, therefore, reflect similar pathway usage. This visual analysis provides a possible explanation for why the salvage reactions in purine metabolism exhibit lower activity during the first few days of the storage period. The second case study displays drastic changes in specific erythrocyte metabolite pools at different times during storage at different temperatures. CONCLUSIONS: The new visualization technique GEM-Vis introduced in this article constitutes a well-suitable approach for large-scale network exploration and advances hypothesis generation. This method can be applied to any system with data and a metabolic map to promote visualization and understand physiology at the network level. More broadly, we hope that our approach will provide the blueprints for new visualizations of other longitudinal -omics data types. The supplement includes a comprehensive user\u27s guide and links to a series of tutorial videos that explain how to prepare model and data files, and how to use the software SBMLsimulator in combination with further tools to create similar animations as highlighted in the case studies

Purification and characterization of recombinant expressed apple allergen Mal d 1

Mal d 1 is the primary apple allergen in northern Europe. To explain the differences in the allergenicity of apple varieties, it is essential to study its properties and interaction with other phytochemicals, which might modulate the allergenic potential. Therefore, an optimized production route followed by an unsophisticated purification step for Mal d 1 and respective mutants is desired to produce sufficient amounts. We describe a procedure for the transformation of the plasmid in competent E. coli cells, protein expression and rapid one-step purification. r-Mal d 1 with and without a polyhistidine-tag are purified by immobilized metal ion affinity chromatography (IMAC) and fastprotein liquid chromatography (FPLC) using a high-resolution anion-exchange column, respectively. Purity is estimated by SDS-PAGE using an image-processing program (Fiji). For both mutants an appropriate yield of r-Mal d 1 with purity higher than 85% is achieved. The allergen is characterized after tryptic in gel digestion by peptide analyses using HPLC-MS/MS. Secondary structure elements are calculated based on CD-spectroscopy and the negligible impact of the polyhistidine-tag on the folding is confirmed. The formation of dimers is proved by mass spectrometry and reduction by DTT prior to SDS-PAGE. Furthermore, the impact of the freeze and thawing process, freeze drying and storage on dimer formation is investigated