2014 - Repozytorium publikacji - Politechnika Gdańska

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Electrochemical simulation of enzymatic transformations studied for the selected antitumor acridine derivatives
- Agnieszka Potęga
- Weronika Hewelt-Belka
- Olga Siewruk
- Katarzyna Zapała
- Zofia Mazerska
2014
The elucidation of the metabolic pathways and the biotransformation mechanisms of potential drugs is a crucial point in drug development. It allows to know the activation routes of the new biologically active compounds, especially in respect to their possible toxicity. Generally, in vivo or in vitro experiments with liver microsomes or hepatocytes are performed. However, these testing schemes are tedious, time consuming and of limited reproducibility. The combination of electrochemistry coupled on-line to mass spectrometry forms a powerful analytical technique with unique applications in the fields of drug metabolism. In an electrochemical flow-through cell, the oxidative metabolism of xenobiotics is simulated. The cell is used in on-line set-up with mass spectrometry, so that an identification of reactive and stable metabolites is possible. Here, we present the benefits of electrochemical metabolism simulation for C-1311 and C-1748, representative antitumor acridines developed in our team. The studied compounds exhibit high cytotoxic activity against a broad spectrum of cell lines in vitro and of transplantable animal tumors. The previous studies on molecular mechanisms of their biochemical action showed that metabolic activation might be a prerequisite stage for the following interactions of these agents with cell macromolecules. Next, we showed that both of them were metabolized by enzymes originating from rat and human liver microsomes. In the presented work C-1311 and C-1748 were chosen as the model drugs to investigate oxidative metabolism under electrochemical conditions coupled to mass spectrometry. The results obtained by EC/MS were then compared with conventional in vitro studies with RLMs as well as HLMs. Electrochemical conversion of both acridines into phase I metabolites was successfully achieved. Comparison of MS results from liver cell microsome incubations with MS results from EC studies allowed to demonstrate that some of the most important metabolic products of the studied compounds were detected both in the conventional enzymatic approach and in the EC simulation. Moreover, newly reported metabolic reaction product of C-1748 become accessible. Summing up, the obtained results confirmed that EC/MS is very well-suited for the simulation of the oxidative metabolism of antitumor acridines. It can be a versatile and user friendly tool in drug discovery and development when applied complementary to established in vitro or in vivo approaches.
Electrochemistry meets enzymes: Investigation of the biotransformation pathway of C-1311 based on electrochemical simulation in comparison to in vitro methods.
- Agnieszka Potęga
2014 Journal 0f Clinical Toxicolgy
The knowledge of the metabolic pathways and the biotransformation of new drugs is one of the major challenges in pharmaceutical research. It is crucial for elucidation of degradation routes of the new biologically active compounds, especially in the area of possible toxicity. Conventional in vitro drug metabolism studies are based on incubating drug candidate with e.g. hepatocytes or, most importantly, liver cell microsomes and isolating and detecting the metabolic products. Microsomes contain a high enzyme concentration of the cytochrome P450 superfamily, which catalyses the majority of oxidative metabolism reactions. As a purely instrumental alternative to mimic drug oxidation reactions occurring in the human body the electrochemical simulation has been developed. Electrochemistry is recently gaining more attention as a tool in rapid, on-line single compound screening. Potential oxidative metabolites are generated in an electrochemical cell and are subsequently identified by on-line mass spectrometry. C-1311 is representative antitumor imidazoacridinone derivative developed in our team. It exhibits high cytotoxic activity against a broad spectrum cell lines in vitro and of transplantable animal tumors. The previous studies showed that the metabolic activation by intracellular enzymes might be necessary for the following interactions of this agent with cell proteins and DNA. Next, we showed that compound was metabolized by enzymes originating from rat and human liver microsomes. In this work C-1311 was chosen as model drug to investigate oxidative metabolism using EC coupled to MS. The results obtained by EC were then compared with conventional in vitro studies with RLMs as well as HLMs. Electrochemical conversion of C-1311 into phase I metabolites was successfully achieved. Comparing MS results from liver cell microsome incubations to MS results from electrochemical studies we were able to demonstrate that two main metabolic products of C-1311 (side chain degradation products) were detected both in the conventional microsomal approach and in the electrochemical simulation. Thus, it can be noted that EC is very well-suited for the simulation of the oxidative metabolism of imidazoacridinone derivative. In summary, our study clearly confirms that EC/MS method is a feasible alternative to microsomal studies. It can be a versatile and userfriendly tool in drug discovery and development when applied complementary to established in vitro or in vivo approaches.
Electronic conductivity in the SiO2-PbO-Fe2O3 glass containing magnetic nanostructures
- Ryszard Jan Barczyński
- Natalia Anna Wójcik
- Jakub Karczewski
- Maria Gazda
2014 SOLID STATE IONICS
The linear impedance spectra of iron–silicate–lead glass samples were measured in the frequency range from 1 MHz to 1 MHz and in the temperature range from 153 K to 423 K. The structure was investigated by means of XRD and atomic force microscopy. Local electrical and magnetic properties of the samples were tested with the aid of electrostatic force microscopy (EFM) and magnetic force microscopy (MFM). The obtained results show that the impedance spectra of all samples exhibit one large relaxation process and some additional small relaxation is present in glass containing 20 mol% and 25 mol% Fe2O3. The AFM micrographs show that in a subset of samples some nanostructures exist. Their size, shape, and quantity depend on the amount of Fe2O3 in the composition of the glass. The samples containing an amount of 15 mol% of Fe2O3 include the biggest nanostructures which are ball-shaped. EFM and MFM micrographs show that nanostructures exhibit different electrical and magnetic behaviors than the rest of the glass matrix. On the basis of Jonscher universal dielectric response the temperature dependence of conductivity exponent s was determined and compared to theoretical models proposed by Elliott. It was found that while in the glass containing less than 15 mol% iron oxide, there is only one process responsible for conduction mechanism, the overlap polaron tunneling. In the other samples, a different conduction mechanism may coexist: quantum mechanical tunneling between semiconducting granules.
ELECTRON-IMPACT IONIZATION CROSS SECTIONS CALCULATIONS FOR PURINE AND PYRIMIDINE MOLECULES
- Bożena Żywicka
- Paweł Możejko
2014
Cross sections for electron-impact ionization of purine and pyrimidine molecules have been calculated using binary-encounter-Bethe method for electron energies ranging from the ionization threshold up to 5 keV. Ionization cross section for purine molecules is 1.4 times higher than for pyrimidine molecules. Acceptable agreement between experimental and theoretical ionization data for pyrimidine molecule has been found.
Electron-impact ionization of fluoromethanes – Review of experiments and binary-encounter models
- Grzegorz P. Karwasz
- Paweł Możejko
- Mi-Young Song
2014 INTERNATIONAL JOURNAL OF MASS SPECTROMETRY
Experiments and recommended data on electron-impact ionization of methane and fluoromethanes (CH3F, CH2F2, CHF3, CF4) are reviewed and compared with binary-encounter models (Gryzinski’s, ´ Deutsch and Märk’s, and Kim and Rudd’s). A good agreement between recent experiments and the two latter classical-like models is shown. Kim and Rudd’s model (calculated presently in the restricted HartreeFock 6-31**G orbital basis) predicts well total ionization cross sections for all five molecules considered. However, counting-ionization cross sections have to be extracted from experimental data to show this agreement. The additivity model of Deutsch and Märk performs equally well, once all molecular orbitals are taken into account. The maxima of total (counting) ionization cross sections calculated presently in Kim and Rudd’s binary-encounter approximation correlate linearly with the molecular polarizability
Electron-scattering cross sections for selected alkyne molecules: Measurements and calculations
- Czesław Szmytkowski
- Paweł Możejko
- Mateusz Zawadzki
- Krzysztof Maciąg
- Elżbieta Ptasińska-Denga
2014 Pełny tekst PHYSICAL REVIEW A
We report cross-section results from experimental and theoretical studies on electron collisions with 1-butyne (HC≡C–CH2CH3) and acetylene (HC≡CH) molecules and from computations for a propyne (HC≡C–CH3) molecule. Absolute grand -total electron-scattering cross sections (TCSs) were measured at impact energies ranging from about 0.5 to 300 eV using the linear electron-transmission method. The TCS energy curve for 1-butyne has a very broad enhancement on which some distinct features are superimposed, namely a resonant-like maximum (located near 3.2 eV), a broad hump (centered around 7.5 eV), and a shoulder (spanned between 12 and 26 eV). The shape of our experimental TCS curve for acetylene closely resembles that reported earlier, while its magnitude is usually larger. As no previous calculations for electron collisions with 1-butyne and propyne are disclosed in the literature, we computed the elastic (ECS) and ionization (ICS) cross sections for these molecules. Similar calculations were also performed for acetylene molecules. The additivity rule was employed to calculate the ECSs from 50 to 3000 eV, while the binary-encounter-Bethe approach was used for computation of the ICSs, from the threshold up to 3000 eV. The sum (ECS + ICS) of these two computed cross sections reasonably reproduces the TCS measurements above 50 eV. Furthermore, the experimental TCS curves, obtained in our laboratory, for a series of acetylenic compounds—acetylene (HC≡CH), propyne (HC≡C–CH3), and 1-butyne (HC≡C–CH2CH3)—are compared to study the substitutional effect. Finally, the influence of the structural differences on the electron-scattering TCS for isomers of the C4H6 molecule (1-butyne, 2-butyne, and 1,3–butadiene) is indicated and discussed.
Elektroenergetyczna automatyka zabezpieczeniowa farm wiatrowych
- Zbigniew Lubośny
2014
Książka prezentuje zagadnienia związane z elektroenergetyczną automatyką zabezpieczeniową farm wiatrowych. Przedstawiono zasady doboru zabezpieczeń sieci farmy wiatrowej (w tym przekładników zabezpieczeniowych) oraz elementów systemu elektroenergetycznego przylegających do farmy wiatrowej. Rozważania powyższe poparto przykładem doboru zabezpieczeń, nastaw zabezpieczeń, przekładników prądowych i napięciowych zabezpieczeniowych dla przykładowej farmy wiatrowej.
Elemental and tight monogamy relations in nonsignaling theories
- R. Augusiak
- Maciej Demianowicz
- M. Pawłowski
- J. Tura
- A. Acín
2014 Pełny tekst PHYSICAL REVIEW A
Physical principles constrain the way nonlocal correlations can be distributed among distant parties. These constraints are usually expressed by monogamy relations that bound the amount of Bell inequality violation observed among a set of parties by the violation observed by a different set of parties. We prove here that much stronger monogamy relations are possible for nonsignaling correlations by showing how nonlocal correlations among a set of parties limit any form of correlations, not necessarily nonlocal, shared among other parties. In particular, we provide tight bounds between the violation of a family of Bell inequalities among an arbitrary number of parties and the knowledge an external observer can gain about outcomes of any single measurement performed by the parties. Finally, we show how the obtained monogamy relations offer an improvement over the existing protocols for device-independent quantum key distribution and randomness amplification.
Elimination of impulsive disturbances from archive audio files – comparison of three noise pulse detection schemes
- Maciej Niedźwiecki
- Marcin Ciołek
2014
The problem of elimination of impulsive disturbances (such as clicks, pops, ticks, crackles, and record scratches) from archive audio recordings is considered and solved using autoregressive modeling. Three classical noise pulse detection schemes are examined and compared: the approach based on open-loop multi-step-ahead signal prediction, the approach based on decision-feedback signal prediction, and the double threshold approach, based on analysis of residual errors. It is shown that the accuracy of the classical schemes can be significantly improved by means of combining the results of forward time and backward time signal processing
Elimination of impulsive disturbances from stereo audio recordings
- Maciej Niedźwiecki
- Marcin Ciołek
2014
This paper presents a new approach to elimination of impulsive disturbances from stereo audio recordings. The proposed solution is based on vector autoregressive modeling of audio signals. On-line tracking of signal model parameters is performed using the stability-preserving Whittle-Wiggins-Robinson algorithm with exponential data weighting. Detection of noise pulses and model-based interpolation of the irrevocably distorted samples is realized using an adaptive, variable-order Kalman filter. The proposed approach is evaluated on a set of clean audio signals contaminated with real click waveforms extracted from silent parts of old gramophone recordings.
Elucidation of transformation pathway of ketoprofen, ibuprofen, and furosemide in surface water and their occurrence in the aqueous environment using UHPLC-QTOF-MS
- Anna Jakimska-Nagórska
- Magdalena Śliwka-Kaszyńska
- Joanna Reszczyńska
- Jacek Namieśnik
- Agata Kot-Wasik
2014 Pełny tekst ANALYTICAL AND BIOANALYTICAL CHEMISTRY
The identification and determination of transformation products (TPs) of pharmaceuticals is essential nowadays, in order to track their fate in the aqueous environment and, thus, to estimate the actual pollution. However, this is a challenging task due to the necessity to apply high-resolution instruments enable to detect known and unknown compounds. This work presents the use of liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) as a powerful tool for the identification of three selected pharmaceuticals, furosemide (FUR), ibuprofen (IBP), and ketoprofen (KET), and their TPs in various water samples. Laboratory degradation experiments were performed using xenon lamp as a source of the irradiation in order to simulate phototransformation processes which may occur in the environment. Furthermore, the photodegradation kinetics of three selected compounds were assessed in a reactor equipped with xenon lamp in river water samples. Five TPs of IBP, seven of KET, and five of FUR were identified; some of them are presented here for the first time. Accurate mass measurements and fragmentation pattern obtained during an LC-QTOF-MS analysis allowed for structure elucidation of TPs followed by the creation of transformation pathway of selected pharmaceuticals. Finally, different water samples (wastewater influent and effluent, river water, untreated and treated water) were analyzed in order to estimate the presence of parent and transformed compounds. Only KET was detected in untransformed form in considered samples. Most of the TPs of selected drugs were found at least once in all water samples. Although IBP and FUR were not present in water samples as parent compounds, their different TPs occur. A great potential of LC-QTOF-MS in the identification and structural elucidation of TPs in the environment, allowing the recognition of the fate of pharmaceuticals in the environment through the determination of transformation pathway, has been presented.
EM-Driven Multi-Objective Optimization of Antenna Structures in Multi-Dimensional Design Spaces
- Sławomir Kozieł
- Adrian Bekasiewicz
- Stanislav Ogurtsov
- Włodzimierz Zieniutycz
2014
Feasible multi-objective optimization of antenna structures is presented. An initial set of Pareto optimal solutions is found using a multi-objective evolutionary algorithm (MOEA) working with a fast surrogate antenna model obtained by kriging interpolation of coarse-discretization EM simulation data. To make the surrogate construction computationally feasible in multi-dimensional design space, the space subset containing non-dominated solutions is identified beforehand using a novel Pareto-ranking based algorithm. The designs obtained by MOEA are subsequently obtained through response correction techniques. Our approach is demonstrated using a planar Yagi antenna.
Emotion Monitoring – Verification of Physiological Characteristics Measurement Procedures
- Agnieszka Landowska
2014 Pełny tekst Metrology and Measurement Systems
This paper concerns measurement procedures on an emotion monitoring stand designed for tracking human emotions in the Human-Computer Interaction with physiological characteristics. The paper addresses the key problem of physiological measurements being disturbed by a motion typical for human-computer interaction such as keyboard typing or mouse movements. An original experiment is described, that aimed at practical evaluation of measurement procedures performed at the emotion monitoring stand constructed at GUT. Different locations of sensors were considered and evaluated for suitability and measurement precision in the HumanComputer Interaction monitoring. Alternative locations (ear lobes and forearms) for skin conductance, blood volume pulse and temperature sensors were proposed and verified. Alternative locations proved correlation with traditional locations as well as lower sensitiveness to movements like typing or mouse moving, therefore they can make a better solution for monitoring the Human-Computer Interaction
Emotion Recognition and Its Applications
- Agata Kołakowska
- Agnieszka Landowska
- Mariusz Szwoch
- Wioleta Szwoch
- Michał Wróbel
2014 Advances in Intelligent Systems and Computing
The paper proposes a set of research scenarios to be applied in four domains: software engineering, website customization, education and gaming. The goal of applying the scenarios is to assess the possibility of using emotion recognition methods in these areas. It also points out the problems of defining sets of emotions to be recognized in different applications, representing the defined emotional states, gathering the data and training. Some of the scenarios consider possible reactions of an affect-aware system and its impact on users.
Emotion Recognition Based on Facial Expressions of Gamers
- Marcin Pilecki
- Michael Suchacz
- Karol Draszawka
2014 Zeszyty Naukowe Wydziału ETI Politechniki Gdańskiej. Technologie Informacyjne
This article presents an approach to emotion recognition based on facial expressions of gamers. With application of certain methods crucial features of an analyzed face like eyebrows' shape, eyes and mouth width, height were extracted. Afterwards a group of artificial intelligence methods was applied to classify a given feature set as one of the following emotions: happiness, sadness, anger and fear. The approach presented in this paper was verified using specialized databases and real-life situations. The obtained results are vastly promising, thus further work on the subject should be continued.
Empirical verification in industrial conditions of fracture mechanics models of cutting power prediction
- Kazimierz Orłowski
- Tomasz Ochrymiuk
- Marcin Lackowski
2014 Pełny tekst Annals of WULS, Forestry and Wood Technology
A comparison of experimental results obtained in the industrial conditions at a sawmill located in the Baltic Natural Forest Region (PL) and theoretical cutting power consumption forecasted with the models which include work of separation (fracture toughness) in addition to plasticity and friction has been described. In computations of cutting power consumption during rip sawing of Scots pine wood (Pinus sylvestris L.) values of fracture toughness and shear yield stresses were taken from previous empirical works, in which samples had been of the same provenance. The carried out analyses revealed conformity of experimental and theoretical results, especially for the model FM-CM, for which differences between them were lower than 3%.
Employees 50+: How They Are Assessed and How They Assess Themselves
- Anita Richert-Kaźmierska
- Katarzyna Stankiewicz
2014 Social Sciences/ Socialiniai Mokslai
In Poland, the older workers are valued for their knowledge and professional experience. Many of them, during transition period, actively participated in the creation of today’ s businesses and now occupy exposed managerial positions, being aware of their own value. On the other hand, old age is one of the main reasons for the limited access to work. The seniors are assigned stereotypical characteristics, such as low levels of education, poor health, troubles with the adaptation to the new conditions, fatigue with work or fear of competition from younger workers. There are also frequent manifestations of ageism. An attempt at testing the validity of assessments and feedback on employees aged 50 years or more generated by themselves and their superiors and co-workers was made in the article. The results collected in eight thematic reports drawn up by the Polish research centres in the years 2005 – 2012 were analysed.
Employees 55+ - valuable resource in SMEs
- Anita Richert-Kaźmierska
2014 Social Sciences/ Socialiniai Mokslai
The article relates to the problem of exploiting the potential of workers aged 55 years or more to build the competitiveness of the SME sector. The aim of the study was an attempt to formulate an answer to the question whether entrepreneurs and managers are able to identify the potential of older workers and whether they use this potential to build the competitiveness of their enterprises. The article is based on the results of a survey conducted among 61 managers of SMEs participating in international project Best Agers Lighthouses
Employing flowgraphs for forward route reconstruction in video surveillance system
- Andrzej Czyżewski
- Karol Lisowski
2014 Pełny tekst JOURNAL OF INTELLIGENT INFORMATION SYSTEMS
Pawlak’s flowgraphs were utilized as a base idea and knowledge container for prediction and decision making algorithms applied to experimental video surveillance system. The system is used for tracking people inside buildings in order to obtain information about their appearance and movement. The fields of view of the cameras did not overlap. Therefore, when an object was moving through unsupervised areas, prediction was needed to identify the same object in the adjacent camera. Moreover, while being unobserved, the object was represented by measurements of probability of appearing in the subsequent camera’s field of view. Those probability values were obtained on the basis of knowledge from the past events contained in the flowgraph. Backward Route Reconstruction methods generated paths of objects providing input for prediction of next steps in the path. This prediction was named as Forward Route Reconstruction. The output of the prediction algorithm is a tree of probabilities of future object movement. Methods for creating a flowgraph from the paths of objects and for obtaining probability values for movement prediction are presented in this paper together with some experimental results and discussion.
Endoscopy video analysis algorithms and their independence of rotation , brightness , contrast , color and blur
- Jan Cychnerski
2014 Pełny tekst International Journal of Innovative Research in Computer and Communication Engineering
The article presents selected image analysis algorithms for endoscopy videos. Mathematical methods that are part of these algorithms are described, and authors’ claims about the characteristics of these algorithms, such as the independence of rotation, brightness, contrast, etc. are mentioned. Using the common test on the real endoscopic image database and a set of image transformations, the validity of these claims was checked and compared between algorithms. Many of the results seem to differ from the declaration of the authors, sometimes even strongly denying them. In addition, some algorithms were found extraordinary sensitive to blurring of the images, which indicates the possibility of using them for the detection of blurry frames, not just diseases.