111 research outputs found
Painlevé equations, topological type property and reconstruction by the topological recursion
55 pages, Minor typos correctedInternational audienceIn this article, we prove that we can introduce a small parameter in the six Painlevé equations through their corresponding Lax pairs and Hamiltonian formulations. Moreover, we prove that these -deformed Lax pairs satisfy the Topological Type property proposed by BergÚre, Borot and Eynard for any generic choice of the monodromy parameters. Consequently we show that one can reconstruct the formal series expansion of the tau-function and of the determinantal formulas by applying the so-called topological recursion on the spectral curve attached to the Lax pair in all six Painlevé cases. Eventually we illustrate the former results with the explicit computations of the first orders of the six tau-functions
RSC Adv.
Despite all the significant progresses made to enhance the efficacy of the existing bank of drugs used to manage and cure type II diabetes mellitus, there is still a need to search and develop novel bioactive compounds with superior efficacy and minimal adverse effects. This study describes the valorization of the natural bioactive sesquiterpene coumarin via the semi-synthesis of new analogs and the study of their α-amylase inhibition activity. The sesquiterpene coumarin named coladonin (1) was quantitatively isolated from the chloroform extract of endemic Ferula tunetana roots. Subsequently, the oxidation of 1 via the Jones oxidation reaction, used as a key reaction, afforded precursor 2. The condensation of oxidized coladonin (2) with various aryl aldehydes provided a series of new arylidene-based sesquiterpene coumarin derivatives (3aâm), which were characterized by NMR and ESI-HRMS experiments. All derivatives evaluated in vitro for their α-amylase inhibitory potential showed interesting α-amylase inhibition with IC50 values ranging from 7.24 to 28.98 ÎŒM. Notably, compounds 3k and 3m exhibited lower IC50 values (7.24 ÎŒM and 8.38 ÎŒM, respectively) compared to the standard (acarbose: IC50 = 9.83 ÎŒM). In addition, the structureâactivity relationship (SAR) for all the compounds was studied. The most active compounds were found to be mixed-type inhibitors, which was revealed by kinetic studies. Furthermore, molecular in silico docking studies were established for all synthesized analogs with the binding site for the α-amylase enzyme
Aromatic maturity is a cornerstone of terroir expression in red wine
This article is published in cooperation with Terclim 2022 (XIVth International Terroir
Congress and 2nd ClimWine Symposium), 3-8 July 2022, Bordeaux, France.Harvesting grapes at adequate maturity is key to the production of high-quality red wines. Viticulturists, enologists, and wine makers define several types of maturity, including physiological maturity, technological maturity, phenolic maturity, and aromatic maturity. Physiological maturity is a biological concept. Technological maturity and phenolic maturity are relatively well documented in the scientific literature, being linked to quantifiable compounds in grape must. Articles on aromatic maturity are scarcer. This is surprising, because aromatic maturity is, probably, the most important of the four in determining wine quality and typicity, including terroir expression, i.e. the identifiable taste of wine in relation to its origin. Optimal terroir expression can be obtained when technological, phenolic, and aromatic maturity are reached at the same time, or within a short time frame. This is more likely to occur when the ripening takes place under mild temperatures, neither too cool, nor too hot.Aromatic expression in wine can be driven, in order from low to high maturity, by green, herbal, spicy, floral, fresh fruit, ripe fruit, jammy fruit, dried fruit, candied, or cooked fruit aromas. Green and cooked fruit aromas are not desirable in red wines, while the levels of other aromatic nuances contribute to the typicity of the wine in relation to its place of origin. Wines produced in cool climates, or on cool soils in temperate climates, are likely to express herbal or fresh fruit aromas, while wines produced under warm climates, or on warm soils in temperate climates, may express ripe fruit, jammy fruit, or candied fruit aromas.This article reviews the state of the art of compounds underpinning the aromas of wines obtained from grapes harvested at different stages of maturity. Advances in the understanding of how aromatic maturity shapes terroir expression and how it can be manipulated by variety choices and management practices, under current and future climatic conditions, are shown. Early ripening varieties perform better in cool climates and late ripening varieties in warm climates. Additionally, maturity can be advanced or delayed by different canopy management practices or training systems. Timing of harvest also impacts aromatic expression of the produced wine. Gaps in the literature are highlighted to guide future directions of research
Retrospective evaluation of whole exome and genome mutation calls in 746 cancer samples
Funder: NCI U24CA211006Abstract: The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC) curated consensus somatic mutation calls using whole exome sequencing (WES) and whole genome sequencing (WGS), respectively. Here, as part of the ICGC/TCGA Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium, which aggregated whole genome sequencing data from 2,658 cancers across 38 tumour types, we compare WES and WGS side-by-side from 746 TCGA samples, finding that ~80% of mutations overlap in covered exonic regions. We estimate that low variant allele fraction (VAF < 15%) and clonal heterogeneity contribute up to 68% of private WGS mutations and 71% of private WES mutations. We observe that ~30% of private WGS mutations trace to mutations identified by a single variant caller in WES consensus efforts. WGS captures both ~50% more variation in exonic regions and un-observed mutations in loci with variable GC-content. Together, our analysis highlights technological divergences between two reproducible somatic variant detection efforts
Reserach on molecular bases of sweetness in dry wines : analytical and sensorial approaches
La saveur sucrĂ©e est Ă lâorigine de lâĂ©quilibre gustatif des vins secs. On observe uneaugmentation de son intensitĂ© au cours de la macĂ©ration post-fermentaire et de lâĂ©levage enbarrique. Nous montrons que ces phĂ©nomĂšnes sont respectivement liĂ©s Ă la libĂ©ration depeptides de la levure et de composĂ©s non-volatils du bois de chĂȘne dans les vins.Le rĂŽle de la protĂ©ine Hsp12 de S. cerevisae sur le gain de sucrositĂ© est Ă©tabli enutilisant des techniques de biologie molĂ©culaire et dâanalyse sensorielle.Le dĂ©veloppement dâun couplage chromatographie de partage centrifuge âgustatomĂ©trie permet de fractionner un extrait de bois de chĂȘne et de purifier plusieurscomposĂ©s sapides. Lâutilisation de la LC-FT/MS et de la RMN nous a permis dâidentifierquatre nouvelles molĂ©cules, appelĂ©es quercotriterpĂ©nosides (QTT), deux dâentre elles (QTTI et III) possĂ©dant une saveur douce. Les seuils de perception du QTT I et dâun lignane amer,le lyonirĂ©sinol, sont respectivement 590 ÎŒg/L et 1.52 mg/L.La mise au point dâune mĂ©thode de quantification de ces composĂ©s en LC-FT/MS nous apermis de dĂ©montrer lâimpact organoleptique du lyonirĂ©sinol dans les vins.Il est probable que les QTT I et III contribuent, directement ou indirectement, au gain desucrositĂ© confĂ©rĂ© par le bois de chĂȘne.Sweetness contributes to the balance in taste of dry wines. An increase in sweet taste isobservable during post-fermentation maceration and oak-barrel aging. We have revealed thatthese phenomena are respectively due to the release in wines of yeast peptides and nonvolatileoak wood compounds.The role of Hsp12 protein from S.cerevisae on the increase in sweetness is establishedwith both molecular biology and sensorial analysis techniques.The development of a method coupling centrifugal partition chromatography andgustatometry has enabled us to fractionate an oak-wood extract and to purify several sapidcompounds. Thanks to both the LC-FTMS and the NMR spectroscopy methods, we havehighlighted four new molecules, called quercotriterpenosides (QTT), out of which QTT Iand III are responsible for a sweet taste. The perception thresholds of QTT I and a bitterlignan, lyoniresinol, are respectively 590 ÎŒg/L and 1.52 mg/L.LC-FT/MS method has been used to develop a quantification method for these compoundsand we have demonstrated the organoleptic impact of lyoniresinol in wines.QTT I and III are likely to contribute, directly or indirectly, to the increase in sweetnessconsecutive to barrel aging in dry wines
Recherches sur les bases moléculaires de la saveur sucrée des vins secs : approches analytique et sensorielle
Sweetness contributes to the balance in taste of dry wines. An increase in sweet taste isobservable during post-fermentation maceration and oak-barrel aging. We have revealed thatthese phenomena are respectively due to the release in wines of yeast peptides and nonvolatileoak wood compounds.The role of Hsp12 protein from S.cerevisae on the increase in sweetness is establishedwith both molecular biology and sensorial analysis techniques.The development of a method coupling centrifugal partition chromatography andgustatometry has enabled us to fractionate an oak-wood extract and to purify several sapidcompounds. Thanks to both the LC-FTMS and the NMR spectroscopy methods, we havehighlighted four new molecules, called quercotriterpenosides (QTT), out of which QTT Iand III are responsible for a sweet taste. The perception thresholds of QTT I and a bitterlignan, lyoniresinol, are respectively 590 ÎŒg/L and 1.52 mg/L.LC-FT/MS method has been used to develop a quantification method for these compoundsand we have demonstrated the organoleptic impact of lyoniresinol in wines.QTT I and III are likely to contribute, directly or indirectly, to the increase in sweetnessconsecutive to barrel aging in dry wines.La saveur sucrĂ©e est Ă lâorigine de lâĂ©quilibre gustatif des vins secs. On observe uneaugmentation de son intensitĂ© au cours de la macĂ©ration post-fermentaire et de lâĂ©levage enbarrique. Nous montrons que ces phĂ©nomĂšnes sont respectivement liĂ©s Ă la libĂ©ration depeptides de la levure et de composĂ©s non-volatils du bois de chĂȘne dans les vins.Le rĂŽle de la protĂ©ine Hsp12 de S. cerevisae sur le gain de sucrositĂ© est Ă©tabli enutilisant des techniques de biologie molĂ©culaire et dâanalyse sensorielle.Le dĂ©veloppement dâun couplage chromatographie de partage centrifuge âgustatomĂ©trie permet de fractionner un extrait de bois de chĂȘne et de purifier plusieurscomposĂ©s sapides. Lâutilisation de la LC-FT/MS et de la RMN nous a permis dâidentifierquatre nouvelles molĂ©cules, appelĂ©es quercotriterpĂ©nosides (QTT), deux dâentre elles (QTTI et III) possĂ©dant une saveur douce. Les seuils de perception du QTT I et dâun lignane amer,le lyonirĂ©sinol, sont respectivement 590 ÎŒg/L et 1.52 mg/L.La mise au point dâune mĂ©thode de quantification de ces composĂ©s en LC-FT/MS nous apermis de dĂ©montrer lâimpact organoleptique du lyonirĂ©sinol dans les vins.Il est probable que les QTT I et III contribuent, directement ou indirectement, au gain desucrositĂ© confĂ©rĂ© par le bois de chĂȘne
Reserach on molecular bases of sweetness in dry wines : analytical and sensorial approaches
La saveur sucrĂ©e est Ă lâorigine de lâĂ©quilibre gustatif des vins secs. On observe uneaugmentation de son intensitĂ© au cours de la macĂ©ration post-fermentaire et de lâĂ©levage enbarrique. Nous montrons que ces phĂ©nomĂšnes sont respectivement liĂ©s Ă la libĂ©ration depeptides de la levure et de composĂ©s non-volatils du bois de chĂȘne dans les vins.Le rĂŽle de la protĂ©ine Hsp12 de S. cerevisae sur le gain de sucrositĂ© est Ă©tabli enutilisant des techniques de biologie molĂ©culaire et dâanalyse sensorielle.Le dĂ©veloppement dâun couplage chromatographie de partage centrifuge âgustatomĂ©trie permet de fractionner un extrait de bois de chĂȘne et de purifier plusieurscomposĂ©s sapides. Lâutilisation de la LC-FT/MS et de la RMN nous a permis dâidentifierquatre nouvelles molĂ©cules, appelĂ©es quercotriterpĂ©nosides (QTT), deux dâentre elles (QTTI et III) possĂ©dant une saveur douce. Les seuils de perception du QTT I et dâun lignane amer,le lyonirĂ©sinol, sont respectivement 590 ÎŒg/L et 1.52 mg/L.La mise au point dâune mĂ©thode de quantification de ces composĂ©s en LC-FT/MS nous apermis de dĂ©montrer lâimpact organoleptique du lyonirĂ©sinol dans les vins.Il est probable que les QTT I et III contribuent, directement ou indirectement, au gain desucrositĂ© confĂ©rĂ© par le bois de chĂȘne.Sweetness contributes to the balance in taste of dry wines. An increase in sweet taste isobservable during post-fermentation maceration and oak-barrel aging. We have revealed thatthese phenomena are respectively due to the release in wines of yeast peptides and nonvolatileoak wood compounds.The role of Hsp12 protein from S.cerevisae on the increase in sweetness is establishedwith both molecular biology and sensorial analysis techniques.The development of a method coupling centrifugal partition chromatography andgustatometry has enabled us to fractionate an oak-wood extract and to purify several sapidcompounds. Thanks to both the LC-FTMS and the NMR spectroscopy methods, we havehighlighted four new molecules, called quercotriterpenosides (QTT), out of which QTT Iand III are responsible for a sweet taste. The perception thresholds of QTT I and a bitterlignan, lyoniresinol, are respectively 590 ÎŒg/L and 1.52 mg/L.LC-FT/MS method has been used to develop a quantification method for these compoundsand we have demonstrated the organoleptic impact of lyoniresinol in wines.QTT I and III are likely to contribute, directly or indirectly, to the increase in sweetnessconsecutive to barrel aging in dry wines
Lignans in spirits: chemical diversity, quantification, and sensory impact of (±)-lyoniresinol
During barrel aging, spirits undergo organoleptic changes caused by the release of aroma and taste compounds. Recently, studies have revealed the bitter properties of oak wood lignans, such as (±)-lyoniresinol, and their contribution to wine taste. To evaluate the impact of lignans in spirits, a targeted screening of 11 compounds was set up and served to validate their presence in this matrix, implying their release by oak wood during aging. After development and validation of a quantification method, the most abundant and the bitterest lignan, (±)-lyoniresinol, was assayed by liquid chromatographyâ»high resolution mass spectrometry (LC-HRMS) in spirits. Its gustatory detection threshold was established at 2.6 mg/L in spirits. A large number of samples quantified were above this detection threshold, which suggests its effect of increased bitterness in spirit taste. Significant variations were observed in commercial spirits, with concentrations ranging from 0.2 to 11.8 mg/L, which could be related to differences in barrel aging processes. In "eaux-de-vie" of cognac, concentrations of (±)-lyoniresinol were observed in the range from 1.6 mg/L to 12 mg/L. Lower concentrations were measured for older vintages
- âŠ