Bootstrap selection of Multivariate Additive PLS Spline models

EnMultivariate Additive PLS Splines, in short MAPLSS, are Partial Least-Squares models that study the dependence of a set of responses on spline transformations of the predictor variables which permit to capture additively non linear main effects and interactions. The aim of this paper is to present a way of selecting MAPLSS models through an adaptive incremental selection of training samples by a bootstrap procedure. This approach is attractive in the case of expensive data thus implying to construct efficient models based on small training data sets

Optimization of a synthetic mixture composed of major Trichoderma reesei enzymes for the hydrolysis of steam-exploded wheat straw

<p>Abstract</p> <p>Background</p> <p>An efficient hydrolysis of lignocellulosic substrates to soluble sugars for biofuel production necessitates the interplay and synergistic interaction of multiple enzymes. An optimized enzyme mixture is crucial for reduced cost of the enzymatic hydrolysis step in a bioethanol production process and its composition will depend on the substrate and type of pretreatment used. In the present study, an experimental design was used to determine the optimal composition of a <it>Trichoderma reesei </it>enzyme mixture, comprising the main cellulase and hemicellulase activities, for the hydrolysis of steam-exploded wheat straw.</p> <p>Methods</p> <p>Six enzymes, CBH1 (Cel7a), CBH2 (Cel6a), EG1 (Cel7b), EG2 (Cel5a), as well as the xyloglucanase Cel74a and the xylanase XYN1 (Xyl11a) were purified from a <it>T. reesei </it>culture under lactose/xylose-induced conditions. Sugar release was followed in milliliter-scale hydrolysis assays for 48 hours and the influence of the mixture on initial conversion rates and final yields is assessed.</p> <p>Results</p> <p>The developed model could show that both responses were strongly correlated. Model predictions suggest that optimal hydrolysis yields can be obtained over a wide range of CBH1 to CBH2 ratios, but necessitates a high proportion of EG1 (13% to 25%) which cannot be replaced by EG2. Whereas 5% to 10% of the latter enzyme and a xylanase content above 6% are required for highest yields, these enzymes are predicted to be less important in the initial stage of hydrolysis.</p> <p>Conclusions</p> <p>The developed model could reliably predict hydrolysis yields of enzyme mixtures in the studied domain and highlighted the importance of the respective enzyme components in both the initial and the final hydrolysis phase of steam-exploded wheat straw.</p

Traitement statistique et typologie d'impulsions de foudre recueillies lors de la campagne de mesures lancee par le CNET-Lannion A : codage en variables qualitatives ordinales et classification de signaux par l'algorithme de vraisemblance des liens

SIGLECNRS T Bordereau / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Bootstrap selection of Multivariate Additive PLS Spline models

EnMultivariate Additive PLS Splines, in short MAPLSS, are Partial Least-Squares models that study the dependence of a set of responses on spline transformations of the predictor variables which permit to capture additively non linear main effects and interactions. The aim of this paper is to present a way of selecting MAPLSS models through an adaptive incremental selection of training samples by a bootstrap procedure. This approach is attractive in the case of expensive data thus implying to construct efficient models based on small training data sets

Kinetics of Carbon Dioxide with Amines. I. Stopped-Flow Studies in Aqueous Solutions. A Review

International audienceIt is possible to find plenty of information about kinetics of reaction between amine and carbone dioxide in the literature. However, there are several experimental techniques and several possible mechanisms which lead to observe sometimes high dispersion of experimental results with various interpretations. A method which enables to compare kinetic constant got by different authors is proposed in this work. First, we present experimental techniques and justify comparison of data obtained by stopped-flow technique. Then, we plot kinetic data for all amines studied in the literature by a power law dependency with the concentration. This representation illustrates some structure-activity relationships and enables to confront experimental results with the different mechanisms. Advantages and limits of each mechanism are discussed. Finally, we justify the choice of the termo-lecular model to compare data got by different authors. This model leads to a compensation effect which is an argument in favour of this mechanism

Correlation between CO2 absorption capacity and amine molecular structures using a High throughput screening methodology

International audienceA major amount of greenhouse gas emissions comes from coal-fired power station generating large quantities of CO2. Post-combustion carbon capture and storage (CCS) using amine solutions is one of the most mature solutions developed to reduce these emissions. However, the benchmark molecule (MEA) suffers from the high energy required to regenerate the solution. Thus, it is necessary to identify amine structures which minimize the energy consumption of the process. In our study, we focus on establishing a correlation between molecular structure and thermodynamics properties of amine solution. First, we use a High Throughput Screening (HTS) experimental device to determine the absorption isotherms of several amine solutions. Then, we build a statistical model using a quantitative structure activity relationship (QSAR) approach, in order to correlate amine structures to their absorption properties. Finally, this statistical model is applied to a set of new molecules to predict their thermodynamic propertie

New Amines for CO2 Capture. IV. Degradation, Corrosion, and Quantitative Structure Property Relationship Model

International audienceDegradation of 22 compounds was evaluated in stainless steel batch reactors at 140 °C for 14 days under a pressure of 0.5 MPa (mixture of 75% CO2, 20% N2, and 5% O2). For each run, two corrosion coupons, one carbon steel (XC38) and one stainless steel (304Ti), were immersed in aqueous solutions of amines to determine corrosion due to degraded solutions. Two additional coupons were put in the vapor phase above solutions. At the end of the run, corrosion rates were evaluated through weight-loss measurements. The amounts of remaining starting material were determined with a quantitative gas chromatography method. Corrosion and degradation data were compared with those of a benchmark molecule (MEA, monoethanolamine), tested under the same conditions. Results indicate that some molecules are less corrosive and have a better chemical stability than MEA. In addition, a quantitative structure property relationship (QSPR) model was built that can be applied to predict compound degradation

Metabolic Profiling of Hybrids Generated from Pummelo and Citrus latipes in Relation to Their Attraction to Diaphorina citri, the Vector of Huanglongbing

The citrus industry at present is severely affected by huanglongbing disease (HLB). HLB is caused by the supposed bacterial pathogen &ldquo;Candidatus Liberibacter asiaticus&rdquo; and is transmitted by the insect vector, the Asian citrus psyllid, Diaphorina citri Kuwayama. Developing new citrus hybrids to improve HLB management is much needed. In this study, we investigated the metabolomic profiles of three new hybrids produced from the cross of C2-5-12 Pummelo (Citrus maxima (L.) Osbeck) &times; pollen from Citrus latipes. The hybrids were selected based on leaf morphology and seedling vigor. The selected hybrids exhibited compact and upright tree architecture as seen in C. latipes. Hybrids were verified by simple sequence repeat markers, and were subjected to metabolomic analysis using gas chromatography-mass spectrometry. The volatile organic compounds (VOCs) and polar metabolites profiling also showed that the new hybrids were different from their parents. Interestingly, the levels of stored VOCs in hybrid II were higher than those observed in its parents and other hybrids. The level of most VOCs released by hybrid II was also higher than that released from its parents. Additionally, the preference assay showed that hybrid II was more attractive to D. citri than its parents and other hybrids. The leaf morphology, compact and upright architecture of hybrid II, and its attraction to D. citri suggest that it could be used as a windbreak and trap tree for D. citri (double duty), once its tolerance to HLB disease is confirmed. Our results showed that metabolomic analysis could be successfully used to understand the biochemical mechanisms controlling the interaction of D. citri with its host plants