Oxana Ye Rodionova

Semenov Institute of Chemical Physics · Department of Kinetics and Catalysis

Background Primary angle closure glaucoma (PACG) is still one of the leading causes of irreversible blindness, with a trend towards an increase in the number of patients to 32.04 million by 2040, an increase of 58.4% compared with 2013. Health risk assessment based on multi-level diagnostics and machine learning–couched treatment algorithms tailore...

Background: Primary angle-closure glaucoma (PACG) is still one of the leading causes of irreversible blindness, with a trend towards an increase in the number of patients to 32.04 million by 2040, an increase of 58.4% compared with 2013. Health-risk assessment based on multi-level diagnostics and machine learning couched treatment algorithms tailor...

Multi-block classification method based on the Data Driven Soft Independent Modeling of Class Analogy (DD-SIMCA) is presented. A high-level data fusion approach is used for the joint analysis of data collected with the help of different analytical instruments. The proposed fusion technique is very simple and straightforward. It uses a Cumulative An...

A generalization of Procrustes Cross-Validation - recently introduced novel approach for validation of chemometric models - is proposed. The generalized approach is faster than its predecessor by several orders of magnitude and can be used for validation of a wider range of models. Furthermore, it provides new tools for exploring the heterogeneity...

It is proposed to use DD-SIMCA method, and, particularly, Full Distancse (FD) as an analytical signal that characterizes each sample in the frame of a classification task. The approach is demonstrated using medical data. FD values help to assess the proximity of each patient to the target class of the control (healthy) subjects. Furthermore, the FD...

Prcis: Treatment strategy of primary angle closure (PAC) is not clear due to the large number of clinical and anatomical-topographic parameters in PAC, influencing treatment algorithm. Using the machine learning method DD-SIMCA, we justify the expediency of early lens extraction in PAC. Purpose: to compare the anatomical and functional efficacy...

This study presents the kinetic modeling of the natural long-term aging of the pharmaceutical substance as well as the intact tablets of Diclofenac. Datasets are collections of near-infrared spectra acquired from the intact tablets packed in plastic blisters and the spectra of the pure substance. Fresh samples and samples at different stages of deg...

Purpose . To evaluate the application of the principal component analysis (PCA) and DD-SIMCA in a comparative analysis of the surgical treatment of primary angle closure. Material and methods . The prospective study included 90 patients. Group 1 — 30 patients with primary angle closure (PAC) with planned laser peripheral iridotomy (LPI). Group 2 —...

This study presents the analysis of the natural long-term aging of both the intact tablets and the active pharmaceutical ingredient. No forced aging conditions were applied to the samples. It is shown that the near infrared spectroscopy of the intact tablets packed in plastic blisters, supported by chemometrics, is a reliable method for detection o...

We proposed a novel method of nanostructure preparation for observation of surface-enhanced Raman spectroscopy (SERS) and metal-enhanced fluorescence (MEF) based on the deposition of gold nanoparticles (GNPs) above the thin dye film by dry aerosol printing. We detected various enhanced SERS and MEF signals of films of malachite green (MG) and rhoda...

The aim of this study is to investigate the influence of hard capsule shells on the possibility of non-invasive monitoring and authentication of medicines presented in capsules dosage form. It is shown that the NIR measurements followed by the chemometric analysis, reflects all macro-components of the analyzed samples, which are the PVC blister, th...

This article considers current trends and challenges in qualitative analysis. The focus is not on classification methods per se, but rather on their general features, such as the way the classification results are presented (hard or soft classification), or how the method is applied (single-class or multi-class). We put forward the main problems, w...

Basic tools for exploration and interpretation of Principal Component Analysis (PCA) results are well-known and thoroughly described in many comprehensive tutorials. However, in the recent decade, several new tools have been developed. Some of them were originally created for solving authentication and classification tasks. In this paper we demonst...

We suggest using a new tool, Procrustes cross-validation, as an alternative to a regular cross-validation for short datasets where each sample is important and, therefore, cannot be removed in line with the conventional leave-one-out cross-validation procedure. The advantages of the new approach are demonstrated using two real-world examples: the f...

div> Basic tools for exploration and interpretation of Principal Component Analysis (PCA) results are well- known and thoroughly described in many comprehensive tutorials. However, in the recent decade, several new tools have been developed. Some of them were originally created for solving authentication and classification tasks. In this paper we...

“Basmati” is the name used for a class of rice comprising a few defined varieties grown in several defined regions of the Indo-Gangetic Plains in India and Pakistan. Due to its highly valued qualities Basmati rice is sold at a premium price, which makes it susceptible to fraud due to economically motivated adulteration. Unscrupulous producers or di...

In this paper we propose a new approach for validation of chemometric models. It is based on k-fold cross-validation algorithm, but, in contrast to conventional cross-validation, our approach makes possible to create a new dataset, which carries sampling uncertainty estimated by the cross-validation procedure. This dataset, called pseudovalidation...

In this study a quick and efficient routine procedure for food fraud detection by multiple adulterants is presented. Non-targeted analysis employs the Near Infrared (NIR) spectroscopy measurements and one-class classification modeling as the chemometric data processing. The approach is illustrated by the analysis of a large collection of NIR spectr...

Soft independent modeling of class analogy (SIMCA by Wold) is a statistically based class modeling approach, which has numerous modifications. Two basic statistics, the score and orthogonal distances, are utilized in all known SIMCA versions. The difference between the methods is the way they interpret and apply statistics in decision rules. The fo...

An open source MATLAB tool implementing the standard Partial least squares discriminant analysis (PLS-DA) method as well as its recent developments, known as multiclass PLS-DA in hard and soft versions, is presented. The main functionality of the tool and usage scenarios are described using a real-world example. A brief introduction to the underlyi...

div> In this paper we propose a new approach for validation of chemometric models. It is based on k-fold cross-validation algorithm, but, in contrast to conventional cross-validation, our approach makes possible to create a new dataset, which carries sampling uncertainty estimated by the cross-validation procedure. This dataset, called pseudo-vali...

The chemometric issues related to the application of non-targeted analysis for the detection of food frauds were analyzed employing discriminant analysis and a one-class classifier. The similarities and differences between the two methods were investigated. The results of classification are characterized by a set of indices called figures of merit....

Previously, we have introduced an approach for calculation of the full object distance in the frame of Principal Component Analysis that can be applied to data exploration and classification. Now, a similar approach has been developed for regression problems in which a total distance can be calculated for every sample in projection modeling. Based...

Edible bird’s nest (EBN) is widely consumed in South-East Asia as a health food product. In recent years, the adulteration of EBN is quite common due to its high economic value and limited supplies of the natural authentic product. Authentication and traceability of EBN demands time-consuming sequential analytical measurements to confirm that the p...

In this work, different chemometric tools were compared to classify n = 26 conventional (CONV) and n = 19 organic (ORG) coffees from the main Brazilian producing regions based on the chemical composition, physicochemical properties, and antioxidant activity. Principal component analysis separated ORG and CONV coffees but the distinction among the p...

Chemometrics is a set of mathematical and statistical methods that are used to detect food frauds, microbial growth, and optimize design of experiments while extracting useful information form large and complex datasets. Complex datasets quite often have numerous sources of variations, with one or more dependent variables assessed against the two o...

A detailed step-by-step procedure for revealing counterfeit and substandard tablets is presented. Non-invasive NIR measurements are used for data collection. The entire complex multi-layer object as the "packaging -coating-core" system requires special treatment at all stages of model development and validation. The influence of each layer is studi...

The ultimate goal of the study is to present a method of authentication of hard-shell capsules of medicines packed in polyvinylchloride (PVC) blisters without damaging the primary packaging. This is done by collecting NIR spectra in a non-invasive mode and subsequent analysis of measurements by a one-class classification procedure. The first part o...

This paper investigates a feasibility of using confocal Raman spectroscopy (CRS) and multivariate analysis for classification of sperm cells. The spectral based classification is compared with the morphological analysis, which is the main criterion for sperm selection in intracytoplasmic sperm injection procedure. The spectral analysis is conducted...

The contribution of chemometrics to important stages throughout the entire analytical process such as experimental design, sampling, and explorative data analysis, including data pretreatment and fusion, was described in the first part of the tutorial "Chemometrics in analytical chemistry." This is the second part of a tutorial article on chemometr...

Vityaz at the Crossroads by Viktor Mikhailovich Vasnetsov, 1882. Decision making is an important part of our lives, and chemometrics contributes to making choices more purposeful. Sometimes choosing the wrong way can lead to serious trouble. As written on the stone in the illustration, “If you ride to the left, you will lose your horse, if you rid...

Here, the theory of the multi‐class partial least squares discriminant analysis (PLS‐DA) is presented. A distinct feature of this theory is that it does not utilize PLS scores but is entirely based on the predicted dummy responses. It is shown that the results of the multi‐class PLS‐DA can be presented in a straightforward way by projecting the res...

Counterfeit medicines of ‘high quality’ are the most difficult to detect as they have the same chemical composition as the genuine ones, but they are produced by underground manufacturers who violate technological regulations. Our approach is to consider a remedy as a whole object, taking into account the complex composition of APIs, excipients and...

In the last decade, the use of multivariate statistical techniques developed for analytical chemistry, has been adopted widely in food science and technology. Usually, chemometrics is applied when there is a large and complex dataset, in terms of sample numbers, types, and responses. The results are used for authentication of geographical origin, f...

Chemometrics has achieved major recognition and progress in the analytical chemistry field. In the first part of this tutorial, major achievements and contributions of chemometrics to some of the more important stages of the analytical process, like experimental design, sampling, and data analysis (including data pretreatment and fusion), are summa...

In this study, we consider the reconstruction of a diffuse reflectance near-infrared spectrum of an object (target spectrum) in case the object is covered by an interfering absorbing and scattering layer. Recovery is performed using a new empirical method, which was developed in our previous study. We focus on a system, which consists of several la...

Investigation of a sample covered by an interfering layer is required in many fields, e.g., for process control, biochemical analysis, and many other applications. This study is based on the analysis of spectra collected by near-infrared (NIR) diffuse reflectance spectroscopy. Each spectrum is a composition of a useful, target spectrum and a spectr...

Authentication is the process of determining whether an object is, in fact, what it is declared to be. In practice, this problem is often solved by using discriminant methods. In this paper, we explain that such techniques do a poor authentication job. The main drawback of discriminant methods is their inability of proper classification of new samp...

An approach is proposed for recovering individual spectra of components in two-layer systems using the method of multivariate curve resolution–alternating least squares. The method is applicable to recording spectra in the near infrared region in both transmission and diffuse reflectance modes. The efficiency of the method is tested on a model syst...

A novel non-linear regression method for modeling non-isothermal thermogravimetric data is proposed. Experiments for several heating rates are analyzed simultaneously. The method is applicable to complex multi-stage processes when the number of stages is unknown. Prior knowledge of the type of kinetics is not required. The main idea is a consequent...

It is shown that the recently proposed Non-Linear Multivariate Curve Resolution (NL-MCR) method can be effectively employed to develop an accurate calibration of cerium(III) using spectrophotometry measurements of mixtures of rare earth elements in nitric acid. Spectroscopic techniques provide a unique opportunity for the in-line determination of c...

Bilinearity is the basic principle of multivariate curve resolution. In this paper, we consider a case when this premise is violated. We demonstrate that the alternating least squares approach can still be used to solve the problem. The developed theory is applied to calibration of spectral data that includes the so-called saturated peaks, which ar...

A novel method for theoretical calculation of the type II (β) error in soft independent modeling by class analogy is proposed. It can be used to compare tentatively predicted and empirically observed results of classification. Such an approach can better characterize model quality and thus improve its validation. Method efficiency is demonstrated o...

For the construction of a reliable decision area in the soft independent modeling by class analogy (SIMCA) method, it is necessary to analyze calibration data revealing the objects of special types such as extremes and outliers. For this purpose, a thorough statistical analysis of the scores and orthogonal distances is necessary. The distance value...

When several near-infrared instruments are used in a network and a common chemometric model is applied to spectral processing, comparison of the instruments is indispensable. Direct transferability often claimed by the producers should be treated with caution. It has been found experimentally that when measurements are performed with the help of a...

The role of chemometrics in process analytical technology (PAT) solutions development is presented in the review on the basis of publications from 1993 to 2011. Main areas of application, stages of implementation, instruments, and chemometric methods used for the PAT implementations are reviewed. Generally speaking, PAT is considered to be an appro...

A new method for the prediction of the drug release profiles during a running pellet coating process from in-line near infrared (NIR) measurements has been developed. The NIR spectra were acquired during a manufacturing process through an immersion probe. These spectra reflect the coating thickness that is inherently connected with the drug release...

Export Date: 15 November 2011

There is no simple solution to the problem of counterfeit-drug detection. So-called "high-quality fakes" with proper composition are most difficult to reveal. Methods based only on quantitative determination of active ingredients are sometimes insufficient. A more general approach is to consider a remedy as a whole object, taking into account the c...

This paper presents a critical review on “Comprehensive chemometrics. Chemical and biochemical data analysis”, Steven D. Brown, Romà Tauler, Beata Walczak (Eds.), Elsevier, ISBN: 978-0-444-52702-8, Hardcover, 2.200pp, March 2009, € 1360, which is a four-volume set written by about 160 authors from 20 countries. Book evaluation is presented in two f...

Application of near-infrared (NIR) measurements together with chemometric data processing is widely used for counterfeit drug detection. The most difficult counterfeits to detect are the "high quality fakes", which have the proper composition but are produced in violation of technological regulations by underground manufacturers. This study uses su...

The possibility of routine testing of pharmaceutical substances directly in warehouses is of great importance for manufactures, especially taking into account the demands of PAT. The application of NIR instruments with remote fiber optic probe makes these measurements simple and rapid. On the other hand carrying out measurements through closed poly...

The research is aimed at optimization of a hybrid binder formulation that includes water solution of sodium silicate (water glass) and polyisocyanate. Optimization is performed with respect to ten output quality characteristics. Calibration modeling is done as a two-step procedure. At first, PCA is applied to the X block for variable reduction. The...

Various regression methods and new interval approach are two different manners for solution of multivariate calibration problems. Both of these techniques aim to construct a model that associates multiple predictor variables with response and to predict the unknown response value for new predictors. When applied to the same data set both methods pr...

A new technique for representative subset selection is presented. The advocated method selects unambiguously the most important objects among the calibration set and uses this subset for the model development without significant deterioration in the predictive ability. The method is called boundary subset selection and it is an inherent part of the...

A new technique for representative subset selection is presented. The advocated method selects unambiguously the most important objects among the calibration set and uses this subset for the model development without significant deterioration in the predictive ability. The method is called boundary subset selection and it is an inherent part of the...

The key chemometric methods and models used to solve the problems of qualitative and quantitative analysis and for process analytical technology are considered. The achievements in the field of chemometrics made in the last 20 years are surveyed. The trends and prospects for its development are discussed.

Many production processes are carried out in stages. At the end of each stage, the production engineer can analyze the intermediate results and correct process parameters (variables) of the next stage. Both analysis of the process and correction to process parameters at next stage should be performed regarding the foreseeable output property y, and...

Methods of multivariate data analysis are applied for ecological monitoring of the landfills. Traditional waste management approach often fails to reveal the specific areas within a landfill due to the complexity of geometrical configuration and variety of degradation processes. The present investigation is based on three different man-caused forma...

Differential scanning calorimetry (DSC) followed by mathematical data processing can be used instead of the conventional method of long term thermal aging in predicting the activity of antioxidants in polyolefins. In this method, a regression relationship is established between the oxidation initial temperatures measured by DSC (X data) and the oxi...

Methods of process control and optimization are presented and illustrated with a real world example. The optimization methods are based on the PLS block modeling as well as on the simple interval calculation methods of interval prediction and object status classification. It is proposed to employ the series of expanding PLS/SIC models in order to s...

Simple interval calculation is a method for linear modeling and for constructing interval estimates of predictions in a multivariate calibration. Simple interval calculation gives results in a convenient interval form with regard to all the existing uncertainties: measurement errors of predictors and responses, discrepancies of bilinear modeling, a...

Analysis of kinetic data is a necessary stage of investigation of processes mechanisms and predicting of practically important properties. Hard approach to such analysis is a traditional inverse problem of chemical kinetics solving with prescribed a priori system of kinetic equations. Alternative is so-called soft approach in which kinetic model is...

Testing of antioxidants' activity in polyolefin is considered. It is proposed to substitute the conventional Long Term Heating Aging (LTHA) test for the method of Differential Scanning Calorimetry (DSC). Values of the Oxidation Initial Temperature measured by the DSC method (X data) are calibrated using the values of Oxidation Induction Period obta...

Express-methods for detection of counterfeit drugs are of vital necessity. Visual control, dissociating tests or simple color reaction tests reveal only very rough forgeries. The feasibility of information-rich NIR-measurements as an analytical method together with multivariate calibration for mathematical data processing for false drugs detection...

Estimation of the parameters of the Arrhenius equation often leads to multicollinearity, or, in other words, a degenerate set of equations in the least-squares procedure. This circumstance makes it difficult to estimate the unknown parameters. Simple expedients for model modification are suggested that reduce multicollinearity, thus allowing the pa...

This study was devoted to the prediction of polymer material aging. The prediction of the shelf time of tire rubber is used as an example in this article. The main steps of the whole procedure are described. They are the design of the experiment, accelerated aging testing, the construction of a multiresponse mathematical model and parameter estimat...

We introduce a novel approach termed simple interval calculation (SIC) for classification of object status in linear multivariate calibration (MVC) and other data analytical contexts. SIC is a method that directly constructs an interval estimator for the predicted response. SIC is based on the single assumption that all errors involved in MVC are l...

The method of successive estimation of regression parameters, which is widely used in nonlinear regression analysis, is applied to obtain kinetic information from spectral data for the case when the spectra of individual components are unknown. Using a model example with a two-step successive reaction, the reliability of the algorithm is demonstrat...

A dynamic theory of heteronuclear spin systems in solids at high temperatures is developed. A system of nonlinear integral equations for the spin time correlation functions is derived in the self-consistent fluctuating local field approximation taking into account corrections for the correlated local field fluctuations in real crystal lattices. The...

A set of coupled nonlinear integral equations for spin time-correlation functions governing the behavior of solid heteronuclear systems with a great number of equivalent nearest neighbors surrounding every spin in the lattice is derived. Previously we used a similar set of equations to describe β-NMR spectra of Li nuclei. The equations are solved n...