Papers by Riccardo Leardi
Chemometrics and Intelligent Laboratory Systems, 1996
Asymmetrical designs are now widely used in the industrial world. However, the traditional method... more Asymmetrical designs are now widely used in the industrial world. However, the traditional methods to construct them are very poor and difficult to handle. To construct experimental design in 'non-standard' occurrences, algorithmic methods, such as Fedorov's or Mitchell's algorithms, are broadly used. But in case of high dimensionality, this class of algorithms cannot be used. In this paper, a new technique based on the genetic algorithm for constructing experimental designs is described. .net. and pH, could be used. For confidential reasons, the levels of each factors are not given.
Design-Expert 6.0, available from Stat-Ease, Inc., 2021 E. Hennepin Avenue, Ste 480, Minneapolis, MN 55413-2726, USA (E-mail: info@statease.com, Telephone: +1-612-378-9449, Fax: +1-612-378-2152), Price: $995 for a single-user licence. For further information of current prices Journal of Chemometrics, 2003
Journal of Chemometrics, 2002
Journal of Chemometrics, 2005
ABSTRACT
Biotechnology progress, Jan 24, 2015
This work presents a sequential data analysis path, which was successfully applied to identify im... more This work presents a sequential data analysis path, which was successfully applied to identify important patterns (fingerprints) in mammalian cell culture process data regarding process variables, time evolution and process response. The data set incorporates 116 fed-batch cultivation experiments for the production of a Fc-Fusion protein. Having precharacterized the evolutions of the investigated variables and manipulated parameters with univariate analysis, principal component analysis (PCA) and partial least squares regression (PLSR) are used for further investigation. The first major objective is to capture and understand the interaction structure and dynamic behavior of the process variables and the titer (process response) using different models. The second major objective is to evaluate those models regarding their capability to characterize and predict the titer production. Moreover, the effects of data unfolding, imputation of missing data, phase separation, and variable tra...
ABSTRACT We use a genetic algorithm (GA) for the feature selection problem. The method explores t... more ABSTRACT We use a genetic algorithm (GA) for the feature selection problem. The method explores the space of possible subsets to obtain the set of features that maximizes the predictive accuracy and minimizes irrelevant attributes. We introduce a multiple correlation in a fitness function used by the GA to evaluate the fitness of each feature subset regarding relationship in its domain. Comparison between our fitness function and the traditional fitness function is done on five problem domains. The empirical results demonstrate that the proposed fitness function is more effective compared to the traditional fitness function on all cases considered
Journal of Pharmacology and Experimental Therapeutics
ABSTRACT
Annali dell'Istituto superiore di sanita
Data Handling in Science and Technology, 2003
Analytica Chimica Acta, 2015
The recent technological advancements of liquid chromatography-tandem mass spectrometry allow the... more The recent technological advancements of liquid chromatography-tandem mass spectrometry allow the simultaneous determination of tens, or even hundreds, of target analytes. In such cases, the traditional approach to quantitative method validation presents three major drawbacks: (i) it is extremely laborious, repetitive and rigid; (ii) it does not allow to introduce new target analytes without starting the validation from its very beginning and (iii) it is performed on spiked blank matrices, whose very nature is significantly modified by the addition of a large number of spiking substances, especially at high concentration. In the present study, several predictive chemometric models were developed from closed sets of analytes in order to estimate validation parameters on molecules of the same class, but not included in the original training set. Retention time, matrix effect, recovery, detection and quantification limits were predicted with partial least squares regression method. In particular, iterative stepwise elimination, iterative predictors weighting and genetic algorithms approaches were utilized and compared to achieve effective variables selection. These procedures were applied to data reported in our previously validated ultra-high performance liquid chromatography-tandem mass spectrometry multi-residue method for the determination of pharmaceutical and illicit drugs in oral fluid samples in accordance with national and international guidelines. Then, the partial least squares model was successfully tested on naloxone and lormetazepam, in order to introduce these new compounds in the oral fluid validated method, which adopts reverse-phase chromatography. Retention time, matrix effect, recovery, limit of detection and limit of quantification parameters for naloxone and lormetazepam were predicted by the model and then positively compared with their corresponding experimental values. The whole study represents a proof-of-concept of chemometrics potential to reduce the routine workload during multi-residue methods validation and suggests a rational alternative to ever-expanding procedures progressively drifting apart from real sample analysis.
Postharvest Biology and Technology, 2012
Grasas y Aceites, 2002
ABSTRACT
Talanta, 2015
A dispersive micro-solid phase extraction (DMSPE) with graphene as a solid adsorbent and ammonium... more A dispersive micro-solid phase extraction (DMSPE) with graphene as a solid adsorbent and ammonium pyrrolidinedithiocarbamate (APDC) as a chelating agent was proposed for speciation and detemination of inorganic selenium by the energy-dispersive X-ray fluorescence spectrometry (EDXRF). In developed DMSPE, graphene particles are dispersed throughout the analyzed solution, therefore reaction between Se(IV)-APDC complexes and graphene nanoparticles occurs immediately. The concentration of Se(VI) is calculated as the difference between the concentration of selenite after and before prereduction of selenate. A central composite face-centered design with 3 center points was performed in order to optimize conditions and to study the effect of four variables (pH of the sample, concentration of APDC, concentration of Triton-X-100, and sample volume). The best results were obtained when suspension consisting of 200µg of graphene nanosheets, 1.2mg of APDC and 0.06mg of Triton-X-100 was rapidly ...
Science of The Total Environment, 2006
The industrial area of Porto Marghera discharges every year about 1.85 10 9 m 3 of waste waters i... more The industrial area of Porto Marghera discharges every year about 1.85 10 9 m 3 of waste waters in the Lagoon of Venice through its 142 discharge points, 17 of them being constantly active. The Anti-Pollution Department of Magistrato alle Acque, the Venice Water Authority, has been controlling these discharges for many years. The huge database built up during the last years could help the authorities in making choices regarding the water quality of the Venetian environment. The application of chemometric methods to the dataset obtained from chemical analyses of industrial waste water samples (almost 250, for each of them up to 57 chemical variables having been measured) is useful to answer fundamental questions related to the pollution generated by the industrial area: i) which are the main differences among the individual discharge points? ii) is there a temporal trend in global and punctual pollution? iii) which is the discharge point having the strongest relative impact on the waters? The results of the present work allow to 1) identify two different groups of discharge points, discriminated by the level of contamination and by the presence of different contaminants; 2) detect a relevant temporal trend in one of the main outfalls (the industrial and civil waste treatment plant); 3) set up a multivariate strategy to "measure" the relative modification induced on receiving lagoon waters by a single discharge. The application of such a "3-STEP multivariate analysis" to the present and future data of water quality could represent a relevant tool for monitoring industrial activities, providing at the same time a support in management decision processes.
Marine Chemistry, 2004
The distribution of polycyclic aromatic hydrocarbons (PAHs) in the sediments of Porto Torres Harb... more The distribution of polycyclic aromatic hydrocarbons (PAHs) in the sediments of Porto Torres Harbor (north Sardinia, Italy) was investigated by gas chromatography/mass spectrometry (GCMS). PAHs concentrations in the sediment (∑PAHs) ranged from 0.07 to 1.21 μg g −1 ...
Journal of Food Science and Technology, 2012
The objective of the work was to use the method of quantitative descriptive analysis (QDA) to des... more The objective of the work was to use the method of quantitative descriptive analysis (QDA) to describe the sensory attributes of the fermented food products prepared with the incorporation of lactic cultures. Panellists were selected and trained to evaluate various attributes specially color and appearance, body texture, flavor, overall acceptability and acidity of the fermented food products like cow milk curd and soymilk curd, idli, sauerkraut and probiotic ice cream. Principal component analysis (PCA) identified the six significant principal components that accounted for more than 90% of the variance in the sensory attribute data. Overall product quality was modelled as a function of principal components using multiple least squares regression (R (2) = 0.8). The result from PCA was statistically analyzed by analysis of variance (ANOVA). These findings demonstrate the utility of quantitative descriptive analysis for identifying and measuring the fermented food product attributes that are important for consumer acceptability.
Food Science and Technology International, Tokyo, 1996
1 Kikkoman Corporation, 399 Noda, Noda, Chiba 278, Japan 2 Glfu Women 's University, 80 Taro... more 1 Kikkoman Corporation, 399 Noda, Noda, Chiba 278, Japan 2 Glfu Women 's University, 80 Taromaru, Glfu 501-25, Japan 3lnstituto di Analisi eTecnologie Farmaceutiche ed Alimentar~ ... A genetic algorithm (GA) was applied to optimizing sets of aroma components in black ...
Uploads
Papers by Riccardo Leardi