Wyniki wyszukiwania - Biblioteka Nauki

1

An advanced multivariate statistical approach to study coastal sediment data

100%

Simeonova P. , Sarbu C. , Spanos T. , Simeonov V. , Tsakovski S.

Open Chemistry

|

2006

|

tom 4

|

nr 1

68-80

EN

The present paper deals with the application of classical and fuzzy principal components analysis to a large data set from coastal sediment analysis. Altogether 126 sampling sites from the Atlantic Coast of the USA are considered and at each site 16 chemical parameters are measured. It is found that four latent factors are responsible for the data structure (“natural”, “anthropogenic”, “bioorganic”, and “organic anthropogenic”). Additionally, estimating the scatter plots for factor scores revealed the similarity between the sampling sites. Geographical and urban factors are found to contribute to the sediment chemical composition. It is shown that the use of fuzzy PCA helps for better data interpretation especially in case of outliers.

2

Application of a Bayesian estimator for identification of edible oils on the basis of spectrophotometric data

100%

Morawski R. Z. , Niedziński C.

|

2008

|

tom Vol. 15, nr 3

247-266

EN

Spectrophotometric analysis of oil mixtures, containing olive oil, is the subject of this paper. Its objective is to compare a new Bayesian estimator with the constrained least-squares estimator, when applied for estimation of concentrations of components of edible oil mixtures, and to assess its applicability for solving problems of industrial monitoring. The comparison is based on the use of semi-synthetic NIR spectrophotometric data and criteria related to measurement uncertainty.

3

Comparison of LS-type methods for determination of olive oil mixtures of the basis NIR spectral data

100%

Latała A. , Morawski R. Z.

|

2008

|

tom Vol. 15, nr 4

409-420

4

Chemometrics in the assessment of the sustainable development rule implementation

88%

Astel A. , Głosińska G. , Sobczyński T. , Boszke L. , Simeonov V. , Siepak J.

Open Chemistry

|

2006

|

tom 4

|

nr 3

543-564

EN

The sustainable development rule implementation is tested by the application of chemometrics in the field of environmental pollution. A data set consisting of Cd, Pb, Cr, Zn, Cu, Mn, Ni, and Fe content in bottom sediment samples collected in the Odra River (Germany/Poland) is treated using cluster analysis (CA), principal component analysis (PCA), and source apportionment techniques. Cluster analysis clearly shows that pollution on the German bank is higher than on the Polish bank. Two latent factors extracted by PCA explain over 88 % of the total variance of the system, allowing identification of the dominant “semi-natural” and “anthropogenic” pollution sources in the river ecosystem. The complexity of the system is proved by MLR analysis of the absolute principal component scores (APCS). The apportioning clearly shows that Cd, Pb, Cr, Zn and Cu participate in an “anthropogenic” source profile, whereas Fe and Mn are “semi-natural”. Multiple regression analysis indicates that for particular elements not described by the model, the amounts vary from 4.2 % (Mn) to 13.1 % (Cr). The element Ni participates to some extent to each source and, in this way, is neither pure “semi-natural” nor pure “anthropogenic”. Apportioning indicates that the whole heavy metal pollution in the investigated river reach is 12510.45 mg·kg−1. The contribution of pollutants originating from “anthropogenic sources” is 9.04 % and from “semi-natural” sources is 86.53 %.

5

Identification of similar and orthogonal chromatographic thin-layer systems for two-dimensional separations of flavonoids and their analogues

88%

Daszykowski M. , Hawrył M. , Waksmundzka-Hajnos M. , Walczak B.

|

2008

|

tom Vol. 20, no. 3

283-307

EN

In this paper a broad overview of the retention behaviour of twenty flavonoids and their analogues in 74 TLC systems is reported. The compounds were chromatographed on different stationary phases (non-polar and polar-bonded stationary phases - wettable RP18W, silica, and aminopropyl-modified and diol-modified plates) developed with a variety of binary mobile phases (aqueous and non-aqueous). The chemometric techniques principal component analysis and hierarchical clustering were used to evaluate similarities and differences among the chromatographic systems. For selection of the most suitable systems either to perform two-dimensional separation or to enhance overall resolution by merging two stationary phases, indices scoring the separating power of a given system or pair of systems were applied. When separation of all pairs of chromatographic systems was evaluated with the index considered, the theoretical separation achieved in these systems could be visualized as a colour map. This colour map enabled rapid examination of resolution and selection of orthogonal systems enabling acceptable separation of the compounds. On the basis of the colour map it was found that relatively efficient two-dimensional separation of the compounds could be achieved on amino-modified plates developed using 9:1 tetrahydrofuran-water in the first dimension then 9:1, 4:1, 3:1, or 7:3 acetonitrile-water in the second dimension. Theoretically, the best separation could be achieved by combining diol-modified and amino-modified stationary phases and using 3:2 methanol-water and 9:1 acetonitrile-water, respectively, as mobile phases.

6

Chemometric study of soil analysis data

88%

Spanos T. , Simeonov V. , Tsakovski S. , Thiokas D.

Open Chemistry

|

2004

|

tom 2

|

nr 2

402-416

EN

The present paper deals with chemometric interpretation of soil analysis data collected from 31 sampling sites in the region of Kavala and Drama, Northern Greece. The determination of 16 different chemical and physicochemical characteristics is principally needed for prognosis of the land treatment and fertilizing. The study carried out indicates that the application of multivariate statistical approaches could reveal new and specific information about sampling sites. It has been found that they could be divided into four general patterns: pattern 1 contains dominantly inorganic and alkaline soil samples from semi-mountainous regions in close proximity to the seacoast; pattern 2 indicates the same soil sample type and regional location as pattern 1 but is far from the coastal line; pattern 3 includes samples from sites from the plains with organic and alkaline soils with close proximity to the coast; pattern 4 resembles pattern 3 as soil type but involves samples from sites far from the shore. Further, six latent factors were identified, conditionally named “structural”, “acidic”, “nutritional”, “salt”, “microcomponents” and “organic”. Finally, an apportioning procedure was carried out to find the source contributions in the measured analytical values. In this way the routine estimation of the soil quality could be improved.

7

Narzędzia budowania wiedzy o procesie wytwarzania produktu leczniczego w myśl koncepcji Quality by Design.

75%

Ronowicz J.

Farmacja Polska

|

2019

|

tom 75

|

nr 11

648-655

EN

The significant change in the pharmaceutical quality approach (QbD concept, PAT strategy) and focusing on improving the quality of drug products by reducing variability in the manufacturing process force the use of effective tools to discover knowledge about the process and product. The Quality by Design concept is an essential part of the modern approach to pharmaceutical quality. Due to the current trend of being QbD compliant, the use of chemometrics in pharmaceutical sciences is increasing. This strategy can shorten a drug development phase and reduce the overall experimental work and costs. Moreover, continuous process monitoring requires the application of advanced, often non-invasive instrumental analytical techniques that generate a huge amount of process data. Their effective analysis and interpretation is possible thanks to chemometrics. The appropriate chemometric algorithms allow to detect cause-effect relations between the raw materials properties, process parameters and the drug product quality. The detected relations can be easily translated into accurate and rationally justified technological decisions, leading to manufacturing process optimization and consequently significant improvement of drug product quality. The effective building of process and product knowledge within the QbD concept is possible by means of non-invasive analytical methods generating process data sets which in-depth analysis and interpretation is possible with the use of the appropriate chemometric algorithms. The use of chemometric techniques enables better understanding of the effect of material attributes and process factors on the final drug product quality. Prognostic mathematical models can be generated to describe in detail the interrelations between excipients and the critical quality attribute of final formulation. This approach should be taken into consideration by industrial formulation scientists to support rational decision making at the drug product development stage.

PL

Zmiana podejścia do problemu zapewnienia jakości w farmacji przemysłowej (koncepcja QbD, strategia PAT), ukierunkowanie na poprawę jakości produktu leczniczego poprzez redukcję zmienności w procesie wytwarzania wymusza użycie efektywnych narzędzi budowania wiedzy o procesie i produkcie. Ciągłe monitorowanie procesu wytwarzania wymaga zastosowania zaawansowanych, często nieinwazyjnych metod analizy instrumentalnej, które generują ogromną ilość danych procesowych. Ich efektywna analiza i interpretacja jest możliwa dzięki metodom chemometrycznym. Odpowiednie algorytmy chemometryczne pozwalają wykryć zależności przyczynowo-skutkowe między właściwościami użytych surowców, parametrami procesu a jakością produktu leczniczego. Wykryte zależności przekładają się na trafne i racjonalnie uzasadnione decyzje technologiczne, prowadzące do optymalizacji procesu wytwarzania oraz poprawy jakości produktu leczniczego. Efektywne budowanie wiedzy o procesie i produkcie w ramach koncepcji QbD jest możliwe przy użyciu nieinwazyjnych metod analizy instrumentalnej generujących dane procesowe, których dogłębna analiza i interpretacja jest możliwa z wykorzystaniem odpowiednich algorytmów chemometrycznych.

8

A simple approach to the simplex method

75%

Michałowski T. , Rymanowski M. , Pietrzyk A.

|

2008

|

tom Vol. 53, No. 5

743-752

EN

The principles of the simplex method, referred to n-D space, arę recalled in terms of the scalar product of vectors, known from elementary algebra. The elements of a simplex plan-ning matrix, referred to n-D space, arę obtained from simple calculations. A target function, involving accuracy and precision of measurements, has been applied as the criterion of quality of the analyses.

PL

Zasady metody planowania sympleksowego, odniesione do przestrzeni n-wymiarowej (n-D), są zaprezentowane z użyciem pojęcia iloczynu skalarnego, znanego z algebry elementarnej. Elementy macierzy planowania sympleksowego, odniesione do przestrzeni n-D, są otrzymane na podstawie prostych obliczeń. Jako kryterium jakości analiz zaproponowano funkcję celu, obejmującą dokładność i precyzję pomiarów.

9

Chemometria w analityce chemicznej. Cz. I. Specyfika metod chemometrycznych

75%

Mazerski J.

|

2005

|

tom nr 3

11-14

PL

Potok informacji o próbkach staje się z roku na rok coraz obfitszy i coraz trudniej jest wyłowić z niego informację użyteczną. Okazuje się, że skuteczna pomoc może nadejść ze strony technik statystycznego i numerycznego opracowywania danych znanych jako metody chemometryczne.

10

Chemometria jako wydajne narzędzie analizy danych środowiskowych. Cz. 6. Modele Tucker3 i PARAFAC

75%

Astel A.

|

2008

|

tom R. 13, nr 3

36-40

11

Approximation of phenol concentration using novel hybrid computational intelligence methods

75%

Pławiak P. , Tadeusiewicz R.

International Journal of Applied Mathematics and Computer Science

|

2014

|

tom 24

|

nr 1

165-181

EN

This paper presents two innovative evolutionary-neural systems based on feed-forward and recurrent neural networks used for quantitative analysis. These systems have been applied for approximation of phenol concentration. Their performance was compared against the conventional methods of artificial intelligence (artificial neural networks, fuzzy logic and genetic algorithms). The proposed systems are a combination of data preprocessing methods, genetic algorithms and the Levenberg-Marquardt (LM) algorithm used for learning feed forward and recurrent neural networks. The initial weights and biases of neural networks chosen by the use of a genetic algorithm are then tuned with an LM algorithm. The evaluation is made on the basis of accuracy and complexity criteria. The main advantage of proposed systems is the elimination of random selection of the network weights and biases, resulting in increased efficiency of the systems.

12

Comparison of Five Svd-Based Algorithms for Calibration of Spectrophotometric Analyzers

75%

Wagner J. , Morawski R. Z. , Miękina A.

|

nr 2

13

Modelowanie i symulacja jako podstawowy obszar badań chemometrycznych w chemii środowiska.

75%

Kowalkowski T. , Buszewski B.

|

1999

|

tom Vol. 6, nr 11

1121-1130

PL

Gwałtowny rozwój technik komputerowych pozwolił na zastosowanie komputerów osobistych do symulowania naturalnych układów biochemicznych. Powstała też odrębna dyscyplina chemii - chemometria, zajmująca się uzyskiwaniem informacji z wielowymiarowych danych. Sprzężenie tych dwóch technik może być niezmiernie przydatne w nowoczesnym laboratorium chemicznym.

EN

Development of computer techniques permitted to apply the personal computers (PCs) to simulation of natural biochemical systems. In 50`s of our century new discipline of chemistry named chemometrics was also originated. Basic topic of this technique is to obtain information from multidimensional data. Connection these two techniques can be very useful in modern chemical laboratory.

14

Chemometria jako wydajne narzędzie analizy danych środowiskowych. Cz. 7. Szeregi czasowe

63%

Astel A.

|

2008

|

tom R. 13, nr 4

33-37

15

Chemometria w analityce chemicznej. Cz. II. Kalibracja wielowymiarowa

63%

Mazerski J.

|

2005

|

tom nr 4

4-10

16

Niektóre wyzwania metrologii chemicznej

63%

Bałkowiec B. , Jerzak B.

|

2006

|

tom nr 2

46-47

PL

Artykuł powstał jako podsumowanie wyników pracy dyplomowej wykonanej w czerwcu 2005 roku na Studium Podyplomowym w Zakresie Metrologii Chemicznej prowadzonym przez Wydział Chemii Uniwersytetu Warszawskiego, a poświęconej materiałom odniesienia.

17

Chemometria w analityce chemicznej. Cz. III. Analiza rozpoznawcza

63%

Mazerski J.

|

2006

|

tom nr 1

4-12

18

Metody eksploracji danych, analiza skupień i analiza głównych składowych w badaniach monitoringowych wód powierzchniowych

63%

Cieszyńska M. , Wesołowski M.

|

2009

|

tom [Z] 63, 7-8

575-600

EN

The paper presents overview of literature pointing up usefulness of two chemometric methods of data exploration: cluster analysis (CA) and principal component analysis (PCA) for interpretation of multidimensional data obtained during surface water monitoring programme. The exceptional importance of fresh water quality rests on the fact that it determines condition and development of all human beings as well as animals and plants. In sections 1 and 3 a concise description of the two methods of pattern recognition was presented. CA provides visual presentation of clustering mode of samples or variables in the form of tree-like scheme called dendrogram [3, 9]. Samples which exhibit considerable similarity fall into one cluster and at the same time they differ to the greatest extent from samples belonging to other clusters [1, 70-74]. PCA enables significant reduction of data matrix dimension without an excessive loss of information [5, 6, 82]. In addition, PCA provides intelligible graphic visualization of the data structure by scattering samples, described by many variables, on plane formed by the following principal components [74]. In CA methods of calculation the distance between different clusters or objects in a hierarchical dendrogram were also mentioned [75]. They define whether two clusters or objects are sufficiently similar to be joined together into one cluster. It was also denoted that among most commonly applied methods Ward's clustering method turns out to be the best and most effective for surface water monitoring results as it gives the largest number of correctly classified observations. The sections 2 and 4 present several examples of the two multidimensional chemometric techniques application in assessment of surface water quality. It was perceived that CA and PCA allow classification of sampling stations in relation to chemical composition of water and therefore permit to pinpoint areas with similar water quality [5, 82]. CA and PCA also help to indicate areas with distinctive chemical composition of water [6, 73, 90, 105]. They also help to identify factors which determine water quality at different regions [4, 5, 88, 113]. When applied for the results acquired from one watercourse at different sites CA and PCA enable to examine changes of water quality downstream [73, 80, 114]. The two chemometric methods are also useful tools for determination if season of sampling or specific weather conditions can influence variation of physicochemical parameters of water [90, 95, 103]. Other chemometric methods applied for monitoring results evaluation are mentioned in section 5 [74, 75, 116].

19

Zastosowanie metod chemometrycznych w poszukiwaniu markerów autentyczności polskich odmian miodów. Cz. I - pochodzenie botaniczne próbek miodów

63%

Chudzińska M. , Barałkiewicz D.

|

2011

|

tom nr 4

32-35

20

Wzorcowanie wyposażenia pomiarowego laboratorium - dotkliwy wymóg, czy podstawa miarodajności wyników pomiarów, zaufania i pewności działania?

51%

Malesa R. , Matras T.

|

2009

|

tom nr 2

37-43

PL

W każdej sekundzie wykonywanych jest na świecie wiele milionów pomiarów. Pomiary pozwalają nam korzystać rozumnie z otaczającego nas świata, dbać o swoje bezpieczeństwo i monitorować towarzyszące naszemu życiu zjawiska.