Search results for "Multivariate statistical"
showing 10 items of 44 documents
New insight into the aptamer conformation and aptamer/protein interaction by surface-enhanced Raman scattering and multivariate statistical analysis
2021
International audience; We study the interaction between one aptamer and its analyte (the MnSOD protein) by the combination of surface-enhanced Raman scattering and multivariate statistical analysis. We observe the aptamer structure and its evolution during the interaction under different experimental conditions (in air or in buffer). Through the spectral treatment by principal component analysis of a large set of SERS data, we were able to probe the aptamer conformations and orientations relative to the surface assuming that the in-plane nucleoside modes are selectively enhanced. We demonstrate that the aptamer orientation and thus its flexibility rely strongly on the presence of a spacer …
1H NMR Spectroscopy with Multivariate Statistical Analysis as a Tool for a Rapid Screening of the Molecular Changes Occurring During Micro-Oxygenatio…
2008
A red wine from Aglianico vine was subjected to a micro-oxygenation procedure for five weeks. The wine was weekly sampled together with a non micro-oxygenated control and extracted with di-ethyl-ether in order to simplify NMR analyses. In fact, 1 H NMR spectra of the whole wine samples were dominated by water and ethanol signals which pre- vented visibility of the resonances generated by the less concentrated wine components. The 1 H NMR analyses of the di- ethyl-ether extracts revealed an increase of the amount of oxygen-containing materials. Such increase was attributed to a wine ageing process which resulted, hence, fastened by application of micro-oxygenation.
Multivariate Methods Based Soft Measurement for Wine Quality Evaluation
2014
Published version of an article in the journal: Abstract and Applied Analysis. Also available from the publisher at: http://dx.doi.org/10.1155/2014/740754 Open Access Soft measurement is a new, developing, and promising industry technology and has been widely used in the industry nowadays. This technology plays a significant role especially in the case where some key variables are difficult to be measured by traditional measurement methods. In this paper, the quality of the wine is evaluated given the wine physicochemical indexes according to multivariate methods based soft measurement. The multivariate methods used in this paper include ordinary least squares regression (OLSR), principal c…
A grape and wine chemodiversity comparison of different appellations in Burgundy: vintage vs terroir effects.
2013
Abstract This study aimed at assessing the ability of high resolution Fourier Transform Ion Cyclotron Resonance – Mass Spectrometry (FTICR–MS) to differentiate grapes and corresponding wines from distinct vineyards managed by a same producer, according to complex chemical fingerprints. Grape extracts (at harvest) and corresponding wines from four different vineyards, sampled immediately after the alcoholic fermentation over three successive vintages, were analysed by FTICR–MS. Thousands of metabolites that are specific to a given vintage, or a given class (wine, skin or must) could be revealed, thus emphasising a strong vintage effect. The same wines were reanalyzed after a few years in bot…
High precision mass measurements for wine metabolomics
2014
An overview of the critical steps for the non-targeted Ultra-High Performance Liquid Chromatography coupled with Quadrupole Time-of-Flight Mass Spectrometry (UPLC-Q-ToF-MS) analysis of wine chemistry is given, ranging from the study design, data preprocessing and statistical analyses, to markers identification. UPLC-Q-ToF-MS data was enhanced by the alignment of exact mass data from FTICR-MS, and marker peaks were identified using UPLC-Q-ToF-MS(2). In combination with multivariate statistical tools and the annotation of peaks with metabolites from relevant databases, this analytical process provides a fine description of the chemical complexity of wines, as exemplified in the case of red (P…
Sensory analysis of Burgundy Pinot noir wines: A comparison of orthonasal and retronasal profiling
1999
Thirty Burgundy Pinot noir wines were evaluated by quantitative descriptive profile by nose (BN) and by mouth (BM) separately, by a trained panel composed of 12 judges. A specific vocabulary of 20 terms was developed. Sensory results were analyzed and compared by univariate and multivariate statistical techniques. Principal component analyses of the mean ratings BN and BM were fairly comparable regarding correlation among variables and the position of the wines. However, five sensory characteristics seem to be more intensely perceived BM, against 6 BN. Panel discrimination of the wines and panel repeatability in the measure were found to be slightly better BN than BM. A further canonical di…
Identification of local and allochthonous flint artefacts from the Middle Palaeolithical site ‘Abrigo de la Quebrada’ (Chelva, Valencia, Spain) by ma…
2015
This work summarizes the characterization of flint artefacts from the Middle Palaeolithic site ‘Abrigo de la Quebrada’ (Chelva, Valencia, Spain) and flint geological samples collected in the Chelva area. Additionally, some flint artefacts located outside this geographical zone were also analysed and compared with the samples from the Abrigo de la Quebrada site. Flint samples have been studied using methods of macroscopic description and physicochemical analysis [energy dispersive X-ray fluorescence spectrometry (EDXRF) and X-ray diffraction (XRD)]. Multivariate statistical analysis of the EDXRF data and the determination of the crystalline index of quartz, obtained from the XRD patterns, ar…
Multivariate statistical analysis of heavy metals and physico-chemical parameters in the groundwater of Karak District, Khyber Pakhtunkhwa, Pakistan
2021
Groundwater heavy metal pollution is a major concern all around the world. For the assessment of heavy metals and physico-chemical characteristics. groundwater samples were collected from different locations of the Karak District, Pakistan. With the help of the global information system device (GIS), groundwater samples were collected and studied from 47 locations. The present study focused on the water table (WT), water source depth (WSD), pH, electrical conductivity (EC), dissolved oxygen (DO), total dissolved solids (TDS), lead (Pb(II)), silver (Ag(I)), iron (Fe(II)) and chromium (Cr(VI)) parameters. Heavy metals were analyzed by the Atomic Absorption Spectrophotometer (AAS). The Pearson…
Frequency Change Patterns across Proficiency Levels in Japanese EFL Learner Speech
2014
This study investigated the overall patterns of variation across seven oral proficiency levels of 1,263 Japanese EFL learners and native English speakers. The methodological approach combined a learner corpus, language processing techniques, and multivariate statistical analyses to identify patterns of language use. The largest spoken learner corpus in Japan, the National Institute of Information and Communications Technology Japanese Learner English (NICT JLE) Corpus was used for the analysis. This corpus consists of transcribed interviews with 1,281 learners and contains over one million running words of spoken English. The transcriptions were compared with data gathered from 20 native En…
STUDY OF LARGE PELAGIC FISH LIFE-HISTORY TRAITS IN THE CENTRAL MEDITERRANEAN SEA AND PROJECTION UNDER FUTURE CLIMATE CHANGE SCENARIOS
2022
One of the most sensitive life periods for each species is the first life stages (larval and juvenile). The survival rates of pelagic fish larvae in these phases are usually very low and subject to fluctuations, consequently affecting the recruitment of new generations. From historical Tuna landing data, the stock's abundance is fluctuating, especially for Atlantic Bluefin Tuna (ABT) (Thunnus thynnus, Linnaeus, 1758) Eastern stock. It is the largest Mediterranean Tuna and one of the most expensive species in the world. Some studies hypothesized that the fluctuations are dictated by environmental factors, particularly in the early life stages. Therefore, it appears necessary to better unders…