Ivana Stanimirova

Ivana Stanimirova
University of Silesia in Katowice · Institute of Chemistry

Ph.D in Chemometrics (VUB, Brussels)

About

64
Publications
12,236
Reads
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1,491
Citations
Citations since 2016
18 Research Items
698 Citations
2016201720182019202020212022020406080100120
2016201720182019202020212022020406080100120
2016201720182019202020212022020406080100120
2016201720182019202020212022020406080100120
Additional affiliations
June 2022 - present
University of Rochester
Position
  • Visiting Researcher

Publications

Publications (64)
Article
The aim of this work was to check whether a methodology based on the analysis of data that contain the entire phospholipid fatty acid, PLFA, compositions of water samples can be successfully used to interpret spatial and temporal changes in the microbial communities in water reservoirs. The proposed methodology consists of the construction of a mod...
Chapter
This chapter focuses on the exploratory analysis of metabolomic data. The goal of data exploration is to uncover any possible differences in sampling procedures, to examine the between- or within-laboratory variations in the measurement processes, to understand the issues that are associated with the appropriateness of the selected experimental des...
Article
Full-text available
Abstract Systemic metabolic changes after renal transplantation reflect the key processes that are related to graft accommodation. In order to describe and better understand these changes, the 1HNMR based metabolomics approach was used. The changes of 47 metabolites in the serum samples of 19 individuals were interpreted over time with respect to t...
Article
Full-text available
This article discusses the possibility of exploratory data analysis of samples described by second-order chromatographic data affected by peak shifts. In particular, the potential of the kernel Gram matrix representation as an alternative to the necessary and time-consuming alignment step is evaluated. It was demonstrated through several simulation...
Article
Full-text available
This study illustrates the successful application of near-infrared reflectance spectroscopy extended with chemometric modeling to profile Cd, Cu, Pb, Ni, Cr, Zn, Mn, and Fe in cultivated and fertilized Haplic Luvisol soils. The partial least-squares regression (PLSR) models were built to predict the elements present in the soil samples at very low...
Article
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Obituary of the late Professor Emeritus Dr. Joseph A. Sherma, Jr.
Article
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Editorial dedicated to 70th birthday anniversary of Prof. Mieczysław Sajewicz, Co-Editor-in-Chief of Acta Chromatographica
Article
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In this study, we examine the chemical stability of two disazo dyes, namely Solvent Red 19 and 23 (SR 19 and SR 23), under simulated conditions. Both dyes are considered to be chemically stable under normal exploitation conditions and therefore, are used extensively as excise duty components that enable a rapid visual verification of the tax levels...
Poster
Full-text available
Fiscal markers are chemical compounds with unique properties added to diesel oil to label the intended purpose of its usage and indicate expected tax level. In this study, we analyzed chemical changes in model systems with one of two red disazo dyes, the so-called Solvent Red 19 and 164 (concentration of dye equal to 4.6 mg·dm-3), dissolved in hept...
Article
In this study, differences in the chemical compositions of rebated excise duty diesel oil samples that were caused by fuel laundering were investigated. Two possible laundering pathways were simulated using either reduction or adsorption agents in model samples that were spiked with Solvent Yellow 124 and Solvent Red 19. The samples were characteri...
Poster
Full-text available
In EU countries, diesel oil is spiked with chemical substances to indicate tax level and designate its further usage. In Poland, diesel oil designated for regular transport contains Solvent Yellow 124 (a marker compound) and Solvent Red 19 or 164 (a red dye). Even though these substances are considered to be stable, there are many illegal attempts...
Article
The performance of the recently proposed excitation-emission fluorescence method was compared to the method using infrared measurements for the evaluation of the antioxidant properties of intact samples and extracts that had been obtained from tomato pastes. The oxygen radical absorbance capacity assay (ORAC) was applied in order to estimate the an...
Article
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Chronic obstructive pulmonary disease, COPD, affects the condition of the entire human organism and causes multiple comorbidities. Pathological lung changes lead to quantitative changes in the composition of the metabolites in different body fluids. The obstructive sleep apnea syndrome, OSAS, occurs in conjunction with chronic obstructive pulmonary...
Article
Full-text available
In the countries of the European Community, diesel fuel samples are spiked with Solvent Yellow 124 and either Solvent Red 19 or Solvent Red 164. Their presence at a given concentration indicates the specific tax rate and determines the usage of fuel. The removal of these so-called excise duty components, which is known as fuel "laundering", is an i...
Article
Full-text available
The aim of the present research was to examine the effect of conjugated linoleic acids (CLA) supplementation on the activity of enzymes that take part in the synthesis of arachidonic acid (AA) and also to investigate the relation between their activity and the neoplastic process. The enzyme activities were established indirectly, because their meas...
Article
Full-text available
The aim of this study was to assess the influence of diet supplementation of pregnant and breast-feeding female Sprague-Dawley rats with conjugated linoleic acids (CLA) on the Δ6- and Δ5-desaturase activity in hepatic microsomes as well as on fatty acids profile and lipids peroxidation in liver and hepatic microsomes of the progeny with chemically...
Article
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The main goal of this study was to establish the optimum accelerated solvent extraction (ASE) conditions for the isolation of the total phenolics contained in common thyme (Thymus vulgaris L.) based on the results of TLC. Additionally, two different extraction methods, i.e., Soxhlet extraction and ASE, were compared in terms of their relative perfo...
Article
The aim of the study was to investigate the applicability of the likelihood ratio (LR) approach for verifying the authenticity of 178 samples of 3 Italian wine brands: Barolo, Barbera, and Grignolino described by 27 parameters describing their chemical compositions. Since the problem of products authenticity may be of forensic interest, the likelih...
Chapter
In this chapter, foundations of robust statistics are introduced, including classic and robust estimators as well as their statistical properties (breakdown point, efficiency, influence function and equivariance property). Then, some robust methods that have gained popularity in recent years are presented. The major benefit of using robust methods...
Article
The antioxidant properties of various kinds of beers were investigated using electron paramagnetic resonance (EPR) spectroscopy. This was possible by measuring the changes in the intensity of the EPR spectrum that resulted from the interaction of the stable radical DPPH (1,1-diphenyl-2-picrylhydrazyl) with the antioxidants found in a beer sample. T...
Article
In recent years, positive matrix factorization, PMF, has gained popularity in environmental sciences and it has been recommended by the U.S. Environmental Protection Agency as a general modeling tool in air quality control. Among the attractive features contributing to its popularity is that measurement uncertainty information can be incorporated i...
Article
The goal of the present study is to assess the effects of anticancer treatment with cyclophosphamide and cytarabine during pregnancy on the mineralization of mandible bones in 7-, 14- and 28-day-old rats. Each bone sample was described by its X-ray fluorescence spectrum characterizing the mineral composition. The data collected are multivariate in...
Article
Often in analytical practice, a set of samples is described by different types of measurements in the hope that a comprehensive characterisation of samples will provide a more complete picture and will help in determining the similarities among samples. The main focus is then on how to combine the information described by different measurement vari...
Chapter
Full-text available
A large progress in the development of robust methods as an efficient tool for processing of data contaminated with outlying objects has been made over the last years. Outliers in the QSAR studies are usually the result of an improper calculation of some molecular descriptors and/or experimental error in determining the property to be modelled. The...
Article
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The primary focus of the European Union funded project entitled “Establishing a WINE Data Bank for analytical parameters for wines from Third Countries” (WINE-DB project, G6RD-CT-2001-00646-WINE-DB) was the discrimination of wine samples with respect to their geographical origin using only a few chemical parameters. Taking a step further, we have i...
Article
The goal of this study was to examine the possibility of verifying the geographical origin of honeys based on the profiles of volatile compounds. A head-space solid phase microextraction (SPME) combined with comprehensive two-dimensional gas chromatography–time-of-flight mass spectrometry (GC × GC–TOFMS) was used to analyze the volatiles in honeys...
Article
The development of a new drug substance is an expensive and time-consuming process. Therefore, the developers want to maximize the profit from the drug by patenting the concerned molecule as well as its synthesis pathway. In a later stage a faster or cheaper manufacturing process can be developed and patented. The aim of this study is to recognize...
Article
The Tucker method, extended to cope with five-way data, was considered to study the effectiveness of a chosen remediation procedure and the effect of so-called ‘aging’ on the fractionation of heavy metals like Cu, Cd, Zn, Al, Pb, Fe and Mn in contaminated soil. Specifically, the goal was to understand the influence of soil pH (way 1) on the process...
Article
Missing elements and outliers can often occur in experimental data. The presence of outliers makes the evaluation of any least squares model parameters difficult, while the missing values influence the adequate identification of outliers. Therefore, approaches that can handle incomplete data containing outliers are highly valued. In this paper, we...
Article
Because of the increasing problem of drug counterfeiting and the potential danger related as well as the economic losses involved, the pharmaceutical industry and the regulatory instances are interested in the development of anti-counterfeiting and patent protection methodologies. In this paper, the evaluation of measured isotopic ratios by means o...
Article
Full-text available
Biofilms are complex aggregates formed by microorganisms such as bacteria, fungi and algae, which grow at the interfaces between water and natural or artificial materials. They are actively involved in processes of sorption and desorption of metal ions in water and reflect the environmental conditions in the recent past. Therefore, biofilms can be...
Article
The aim of this work was to show usefulness of chemometric analysis in processing of the data describing production of drinking water in the Silesian region of Poland. Water samples have been collected within the period of 1 year and the quality of water was characterized by a number of physical, chemical and microbiological parameters. Principal c...
Article
Gel electrophoresis serves as a basic analytical tool in the proteomic studies. However, processing of gel electrophoretic images is still the main bottleneck of data analysis, and there is an increasing need for the fully automated approaches. The proposed start-to-end strategy of analyzing the gel images consists of chemometric tools, which allow...
Article
In this article a robust version of SIMCA, based on spherical principal component analysis [N. Locantore, J.S. Marron, D.G. Simpson, N. Tripoli, J.T. Zhang, K.L. Cohen, Robust principal component analysis for functional data (with comments), Test 8 (1999) 1–74], is introduced for chemometrics community. The efficiency of the new approach is compare...
Article
An efficient methodology for dealing with missing values and outlying observations simultaneously in principal component analysis (PCA) is proposed. The concept described in the paper consists of using a robust technique to obtain robust principal components combined with the expectation maximization approach to process data with missing elements....
Article
The aim of this study is to show the usefulness of robust multiple regression techniques implemented in the expectation maximization framework in order to model successfully data containing missing elements and outlying objects. In particular, results from a comparative study of partial least squares and partial robust M-regression models implement...
Article
N-way methods, particularly the Tucker method, are often the methods of choice when analyzing data sets arranged in three- (or higher) way arrays, which is the case for most environmental data sets. In the future, applying N-way methods will become an increasingly popular way to uncover hidden information in complex data sets. The reason for this i...
Article
The goal of this study is to derive a methodology for modeling the biological activity of non-nucleoside HIV Reverse Transcriptase (RT) inhibitors. The difficulties that were encountered during the modeling attempts are discussed, together with their origin and solutions. With the selected multivariate techniques: robust principal component analysi...
Article
A data set consisting of fourteen isotopic ratios or quantities derived from such ratios for samples of acetylsalicylic acid (aspirin), commercialized by various pharmaceutical companies from different countries, was analyzed. The goal of the data analysis was to explore whether results can be linked to geographical origin or other features such as...
Article
In environmental chemistry studies, it may be necessary to analyze data sets constituted by different blocks of variables, possibly of different types, measured on the same samples. Multiple factor analysis (MFA) is presented as a tool for exploring such data. The most important features of MFA are shown on a real environmental data set, consisting...
Article
This manuscript shows the usefulness of Projection Pursuit (PP) and Multivariate Regression Trees (MRT) for analytical data exploration. Additionally, features of Projection Pursuit and kurtosis as a projection index are presented. The ability of Projection Pursuit to discover groups in the data is compared to classical Principal Component Analysis...
Article
In this study, the attention is focused on modeling a four-way environmental data set that comes from monitoring of air quality in two industrial regions in Austria, by means of PARAFAC and Tucker models. It appeared that the constructed Tucker model is the most appropriate for the studied data. It gave a possibility to uncover important informatio...
Article
Structuration des Tableaux A Trois Indices de la Statistique (STATIS), a method which can be seen as a 3-way exploratory analysis method, is proposed and investigated for the purpose of batch process monitoring. It is applied to batch process data to monitor the evolution in time of batches, through what are called the compromise plots. Because all...
Article
The present paper deals with the application of different chemometric methods to an environmental data set derived from the monitoring of wet precipitation in Austria (1988-1999). These methods are: principal component analysis (PCA); projection pursuit (PP); density-based spatial clustering of application with noise (DBSCAN); ordering points to id...
Article
The present paper deals with the data exploration of three-way environmental data with the use of “Structuration des Tableaux A Trois Indices de la Statistique” (STATIS). The performance of the method is compared with Tucker3 and PARAFAC2, two more commonly used methods in chemometric N-way data analysis. The features of STATIS are demonstrated on...
Article
The article reports the results of a comparative study of two robust Principal Component Analysis (PCA) algorithms based on Projection Pursuit which can be used for exploratory data analysis. The first one is proposed by Croux and Ruiz-Gazen, denoted as C–R algorithm, and the second one by Hubert et al., introducing its modified version, abbreviate...
Article
Full-text available
This environmetric study deals with modeling and interpretation of river water monitoring data from the basin of the Saale river and its tributaries the Ilm and the Unstrut. For a period of one year of observation between September 1993 and August 1994 a data set from twelve campaigns at twenty-nine sampling sites from the Saale river and six campa...
Article
Multivariate statistical analysis of sediment data (input matrix 122 x 15) collected from 122 sampling sites from the western coastline of the USA and analyzed for 15 analytes indicates that the data structure could be explained by four latent factors. These factors are conditionally named "anthropogenic", "organic", "natural", and "hot spots". The...
Article
Multivariate statistical analysis of sediment data (information matrix 123 × 16) from the Gulf of Mexico, USA shows that the data structure is defined by four latent factors conditionally called “inorganic natural”, “inorganic anthropogenic”, “bioorganic” and “organic anthropogenic” explaining 39.24%, 23.17%, 10.77% and 10.67% of the total variance...

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Projects (3)
Project
My research is focused on the freedom of scientific research as well as dissemination of the fruits thereof, areas of scientific creation in exact sciences and form of establishing results of that research, protection of intellectual property rights to research results especially in exact sciences (in the light of who should be an author of scientific work).
Archived project
Project
We intend to investigate the influence of a few controlled factors, e.g. temperature, storage conditions, and storage time as well as to examine the products obtained from excise duty components under the influential factors using spectroscopic sample characterization by UV-VIS, fluorescence spectroscopy, chromatography, mass spectrometry, and possibly by proton nuclear magnetic resonance spectroscopy. In addition, chemical changes due to photochemical reactions will be considered for model and real fuel samples.