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Publications from the year 2012
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PARP inhibition potentiates the cytotoxic activity of C-1305, a selective inhibitor of topoisomerase II, in human BRCA1-positive breast cancer cells
- Józefa Węsierska-Gądek
- Nora Zulehner
- Franziska Ferk
- Andrzej Składanowski
- Oxana Komina
- Margarita Maurer
Two cellular proteins encoded by the breast and ovarian cancer type 1 susceptibility (BRCA1 and BRCA2) tumor suppressor genes are essential for DNA integrity and the maintenance of genomic stability.Approximately 5-10% of breast and ovarian cancers result from inherited alterations or mutations in these genes.Remarkably, BRCA1/BRCA2-deficient cells are hypersensitive to selective inhibition of poly(ADPribose) polymerase 1 (PARP-1), whose primary functions are related to DNA base excision repair; PARP-1inhibition significantly potentiates the cytotoxicity of various anti-cancer drugs, including inhibitors of topoisomerase I and II. In the present study, we examined the anti-proliferative and pro-apoptotic effects of C-1305, a selective inhibitor of topoisomerase II, on human breast cancer cell lines with different BRCA1 and p53 statuses. BRCA1-competent breast cancer cell lines exhibited different responses to topoisomerase II inhibition. BT-20 cells that express high levels of BRCA1 levels were most resistant to C-1305 than other tested cells. Surprisingly, pharmacological interference with PARP-1 activity strongly inhibited their proliferation and potentiated the efficacy of C-1305 treatment. In contrast, PARP-1 inhibition only weakly affected the proliferation of BRCA1-deficient SKBr-3 cells and was not synergistic with the effects of C-1305. Further experiments revealed that the inhibition of PARP-1 in BT-20 cells caused the accumulation of DNA strand breaks and induced caspase-3 dependent apoptosis. These results seem to indicate that PARP-1 inhibition can potentiate the cytotoxicity of anti-cancer drugs in cancer cells with functional BRCA1 and suggest that mutations in other DNA repair proteins may render cancer cells more sensitive to interference with PARP-1 activity.
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Partial Admission Stages of High Efficiency for a Microturbine
- Krzysztof Kosowski
- Robert Stępień
- Wojciech Włodarski
- Marian Piwowarski
- Łukasz Hirt
The paper presents the results of a design analysis of a micro-turbine for a co-generation micro-power plant working in accordance with organic Rankine cycle. The heat power of the plant is assumed equal to 20kW and the corresponding available electric output is estimated to be about 3kW. After the design analysis, the axial turbine with partial admission in all stages was built and tested experimentally. Special attention was paid to the design of the nozzle cascades forming partial admission arcs. The results showed that, for example, remarkable flow separation zones appeared in the nozzle flow channels placed at the edge of the admission segments. The modifications of these channels reduced the undesirable effect. All the stages were equipped with movable blade shields for reducing windage losses. The effect of the angular position of the shields in the succeeding stages was investigated numerically and experimentally. The examples of the results are shown and discussed in the paper. The proposed micro-turbine has a relatively high efficiency (80%) and the rotor speed of about 8000rpm which seems to be a low value compared with the other considered variants.
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Particle Image Velocimetry Measurements of Airflow in Electrohydrodynamic Device for Dust Particle Collection
- Janusz Podliński
- Artur Berendt
- Jerzy Mizeraczyk
In this paper the electrohydrodynamic (EHD)device for gas pumping and cleaning is presented. To induce an airflow in this EHD device corona discharge was used. The discharge was generated between the one-sided spike electrodes and the plate electrodes. An asymmetric electric field and generated discharge result in unidirectional gas flow through the EHD device. The current-voltage characteristics were measured and the corona discharge power was calculated. The EHDsecondary flow and the average airflow induced in the device duct were measured using 2D PIV method. Obtained results showed that investigated EHD device was capable of producing significant unidirectional airflow with velocities up to 0.64 m/s.
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Particle shape dependence in 2D granular media
- Cegeo Cegeo
- B. Saint-Cyr
- Krzysztof Szarf
- C. Voivret
- E. Azéma
- V. Richefeu
- J.-Y. Delenne
- Gaël Combe
- C. Nouguier-Lehon
- Pascal Villard
- P. Sornay
- M. Chaze
- F. Radjai
Particle shape is a key to the space-filling and strength properties of granular matter. We consider a shape parameter eta describing the degree of distortion from a perfectly spherical shape. Encompassing most specific shape characteristics such as elongation, angularity and non-convexity, eta is a low-order but generic parameter that we used in a numerical benchmark test for a systematic investigation of shape dependence in sheared granular packings composed of particles of different shapes. We find that the shear strength is an increasing function of eta with nearly the same trend for all shapes, the differences appearing thus to be of second order compared to eta. We also observe a non-trivial behavior of packing fraction which, for all our simulated shapes, increases with eta from the random close packing fraction for disks, reaches a peak considerably higher than that for disks, and subsequently declines as eta is further increased. These findings suggest that a low-order description of particle shape accounts for the principal trends of packing fraction and shear strength. Hence, the effect of second-order shape parameters may be investigated by considering different shapes at the same level of eta.
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PARTICLE SIZE ANALYSIS OF SUSPENSIONS IN REMOVING OF ORGANIC MATTER AND PHOSPHORUS FROM WASTEWATER AND SURFACE WATER
- Agnieszka Tuszyńska
- Katarzyna Kołecka
In this paper the particle size of suspended solids in the removing of organic matter and phosphorus compounds from lake water and wastewater treated in the Ecological Treatment Systems (ETS) was analyzed. The invesigated materials were taken from two ETS located in Pomerania Region/Poland. Object in Swarzewo is 3rd stage of biological treatment of municipal wastewater, while object in Kartuzy has task to remove a phosphorus from lake water. To deepen the knowledge about migration of pollutants in water and wastewater their particle size analysis based on the laser diffraction method were carried out. Speciation of phosphorus and organic matter expressed in COD was carried out for the purpose of determination of the participation and type of dissolved substances as well as suspended matter. The granulometric analysis showed that from wastewater and lake water treated in ETS the suspension above size 100 μm is efficiently removed. On the basis of the obtained results it was proved that ETS efficiently remove particulate fractions of phosphorus and organic matter. In wastewater and surface water inflowed to analyzed facilities 30-45% of organic matter and 55-80% of phosphorus was attributed to suspended solids. In the effluent a part of pollutants in suspended fraction decreased and it were 15% for COD and 35% for phosphorus in wastewater and 24% for COD and 50% for phosphorus in lake water.
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Passive Variable Fractional Delay Filter Design using Distributed Maximal Flatness Method
- Marek Blok
W pracy przedstawiono nową metodę projektowania pasywnych filtrów ułakowoopóźniających opartą na metodzie rozproszonej maksymalnej płaskości. W zaproponowane podejście jest uogólnieniem najbardziej popularnej metody projektowania filtrów maksymalnie płaskich - metody projektowania filtrów maksymalnie płaskich. Filtr maksymalnie płaski cechuje bardzo dobra jakość jedynie w wąskim paśmie wokół częstotliwości zerowej, ale jego istotną zaletą jest jego pasywność, która oznacza, że jego charakterystyka częstotliwościowa nigdzie nie jest większa od jedności. To właśnie pasywność tego filtru sprawia, żę pomimo wąskiego pasma dobrej aproksymacji filtry maksymalnie płaskie są tak powszechnie stosowane gdy zmienne opóźnienie jest wymagane w pętli sprzężenia zwrotnego. W zaproponowanym rozwiązaniu warunki gwarantujące maksymalną płaskość charakterystyki częstotliwościowej w klasycznym rozwiązaniu wymuszane dla częstotliwości zerowej, rozpraszane są w całym zakładanym paśmie aproksymacji. W rezultacie otrzymujemy pasywne filtry ułamkowoopóźniające ale o kontrolowanej przez projektanta szerokości pasma aproksymacji. Ponadto, zaproponowana metoda umożliwia zastosowanie funkcji wagi w odniesieniu do różnych funkcji błędu. Jak pokazano, metoda ta może być łatwo przystosowana do realizacji pasywnych filtrów o opóźnieniu zmiennym design.
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Pasywacja stali nierdzewnych
- Stefan Krakowiak
- Juliusz Orlikowski
Odporność chemiczna stali odpornych na korozję oparta jest calkowicie na pasywnym charakterze warstw powierzchniowych istniejących na tych stalach. Pasywność to stan, w którym metal aktywny wykazuje podwyższoną odporność korozyjną dzięki tworzeniu na powierzchni warstewki, która jest stabilna w danym środowisku, pH i potencjale oraz stanowi produkt korozji.
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Pathways of Nitrogen Removal in Hybrid Treatment Wetlands
- Magdalena Gajewska
- Krystyna Ambroch
Hybrid Treatment Wetlands (HTWs) are composed of two or more filters with different modes of flow, allowing the benefits of both types of bed to be combined, resulting in better effluent quality (nitrogen and organic compounds removal). Such a heterogeneous environment creates possibilities for different mechanisms of nitrogen removal. The objective of the present study was to investigate the removal of nitrogen versus a range of parameters, such as hydraulic and organic loading, redox potential, pH, alkalinity, availability of easily decomposable organic compounds and theoretical nitrogenous biological oxygen demand, in order to evaluate nitrogen conversion processes. The studies were carried out in a full-scale HTW designed for 200pe, over two years monitoring period. The HTW achieved stable and very effective removal of all analysed pollutants: BOD5 was 97.9% for average load of 3.4 gm-2·d-1 and 95.1% COD removal for average load of 6.9 gm-2·d-1 (for the entire HTW). Unexpectedly efficient N removal was observed in the first stage of treatment plant. The removal efficiency of TKN was over 46% in this horizontal sub-surface flow bed and was coupled with 80.5% BOD removal, suggesting heterotrophic competition for oxygen, the supply of which was strongly limited in this stage of treatment.
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PBDEs in environmental samples: Sampling and analysis
- Sylwia Król
- Bożena Zabiegała
- Jacek Namieśnik
The paper reviews the subject literature concerning analytical procedures routinely sed for monitoring polybrominated diphenyl ethers (PBDE) in environmental samples. It describes and summarizes subsequent stages of analytical procedure including sample collection and preparation, extraction, clean-up and final determination. Different approaches with their advantages and limitations are presented. Special attention is drawn to the newly developed, promising extraction techniques, especially: liquid-liquid-microextraction (LLME) with its modifications, cloud point extraction(CPE) and hollow fiber microextraction. The review compares available detection techniques taking into account their usefulness for determining different PBDEs in complex matrix as well as discussingpossible limitations that may occur during the analysis. The quality assurance and quality control aspect of analytical procedure is described. Finally special attention is paid to the determination of highly brominated PBDE compounds (e.g. BDE209), which requires implementation of different analytical approach.
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PCR-ELISA: inexpensive alternative to quantitative PCR
- Dorota Drapała
- Milena Kordalewska
- Bartłomiej Ferra
PCR-ELISA (polymerase chain reaction-enzyme linked immunosorbent assay), a combination of PCR and ELISA methods, has been used since late 1980s. The technique is based on specially labelled DNA fragments which are captured by specific DNA sequences and detected by antibodies. The whole procedure of PCR-ELISA is divided into three steps: DNA extraction, PCR reaction and detection by ELISA. The method has been found as very specific and sensitive which allows detection of really small amounts of DNA. Moreover, ELISA step may be automated what makes this technique faster in comparison with classical detection methods. For these reasons PCR-ELISA has been applied in many laboratories in e.g. routine microbiological diagnostics.
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Peptide Permeases in Candida albicans
- Marta Schielmann
- Joachim MORSCHHäUSER
- Sławomir Milewski
Aims: The aim of this work was to characterize oligopeptide uptake in Candida albicans mutants in which the genes encoding putative peptide permeases were selectively disrupted. Initial velocities of transport of model oligopeptides, (Ala)2, (Ala)3, (Ala)4, and sensitivity of mutants to antifungal oligopeptides containing N3-(4-methoxyfumaroyl)-L-2,3-diaminopropanoic acid (FMDP) were determined and compared to those of the wild-type SC5314 strain.Methods: C. albicans mutants lacking one or a set of the genes encoding putative oligopeptide permeases (opt1Δ, opt 23Δ, opt4Δ, opt5Δ, opt6Δ, opt7Δ, opt8Δ, opt12345Δ), the genes coding for di-/tripeptide permeases (ptr222Δ), or all peptide permeases (opt12345ptr222Δ) were constructed in the laboratory of one of the co-authors (JM). Oligopeptides containing FMDP (Nva-FMDP, Lys-Nva-FMDP and (Met)3-FMDP) were synthesized at Gdańsk University of Technology. Peptide uptake was followed using the colorimetric method of determination of peptide concentration employing 2,4,6-trinitrobenzenesulfonate. MIC determination was done using the twofold serial dilution method according to the EUCAST requirements. Additionally, MICs were determined in YNB medium containing different nitrogen sources.Results: All tested mutant strains, except for ptr222Δ and opt12345ptr222Δ, were similarly sensitive to Nva-FMDP and Lys-Nva-FMDP. A correlation between growth inhibitory activity and initial transport velocity was observed. The opt12345ptr222Δ mutant was resistant to FMDP-peptides and unable to transport all tested model peptides. The ptr222Δ mutant was unable to transport (Ala)2 and (Ala)3 and sensitive to (Met)3-FMDP, whereas the opt1Δ mutant was unable to transport (Ala)4 and resistant to the antifungal tetrapeptide. The MIC values of FMDP-oligopeptides highly depended on medium composition. Strong differences between the mutants were noticed in the case of sensitivity to (Met)3-FMDP in YNB medium containing ammonium sulfate as a nitrogen source. An interesting observation, yet to be fully explained, was that the ptr222Δ mutant was sensitive to Lys-Nva-FMDP in YNB medium supplemented with sodium glutamate.Conclusions: The OPT1 gene encodes the oligopeptide permease of major importance. Genes encoding the PTR permeases, PTR2 and PTR22, are essential for the uptake of di- and tripeptides and the sensitivity to antifungal peptides of the same size.
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Peptidoglycan hydrolases - potential weapons against Staphylococcus aureus
- Piotr Szweda
- Marta Schielmann
- Roman Kotłowski
- Grzegorz Gorczyca
- Magdalena Zalewska
- Sławomir Milewski
Bacteria of the genus Staphylococcus are common pathogens responsible for a broad spectrum of human and animal infections and belong to most important etiological factors causing food poisoning. Because of rapid increase in prevalence of isolation of staphylococci resistant to many antibiotics, there is an urgent need for development of new alternative chemotherapeutics. A number of studies have recently demonstrated the strong potential of peptidoglycan hydrolases (PHs) to control and treat infections caused by this group of bacteria. PHs cause rapid lysis and death of bacterial cells. The review concentrates on enzymes hydrolyzing peptidoglycan of staphylococci, usually they are characterized by high specificity to only S. aureus cell wall components, however some of them are also able to lyse cells of other staphylococci e.g. S. epidermidis - growing importance human pathogen and also other groups of bacteria. Some of PHs strengthen the bactericidal or bacteriostatic activity of common antibiotics as a result they should be considered as component of combined therapy which could definitely reduced development of bacterial resistance not only to both enzymes but also antibiotics. The preliminary research revealed that most of these enzymes can be produced using heterologous, especially E. coli expression system, however still much effort is required to develop more efficient and large scale production technologies. This review discusses current state on knowledge with emphasis on the possibilities of application of PHs in the context of therapeutics for infections caused by staphylococci.
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Performance analysis of power swing blocking feature in ABB 670 series impedance relays
- Maciej Łosiński
- Jacek Klucznik
This paper presents test results of a distance protection’s PSD power swing detection feature in ABB 670 series relays. A RED670 relay was tested, which is part of the hydroelectric set protection in Żarnowiec Pumped Storage Plant. The power swing blocking feature’s performance was analysed on the basis of the results of object tests made with an Omicron digital tester. Also presented are simulation results that illustrate the PSD feature’s response to power swings caused by a disturbance in the power system. It is also shown how a distance protection may react to the same fault, depending on its settings.
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Performance Characteristics of a Micro-turbine, International
- Krzysztof Kosowski
- Marian Piwowarski
- Robert Stępień
- Wojciech Włodarski
. In the paper a design of a multi-stage micro-turbine with partial admission of all the stages is described in detail and the results of particular experimental investigations and numerical calculations are shown, followed by conclusions. The co-generative micro-power plant with the HFE7100 as a working medium was designed and built for experimental investigations. The values of the main cycle parameters were as follows:- heat output: 20 kW,- electric output: 3kW,- rotor speed: 8000rpm -12000rpm.The micro-turbine experimental stand was designed to enable the measurement of the electric output, rotor speed, medium mass flow rate and the working medium parameters (pressure, temperature) in nearly 40 points located along the turbine and on its circumference. The turbine performance was calculated for HFE7100 but also for air and nitrogen as a working medium for testing purposes. In the first stage of experiments the turbine behaviour was checked using these gases and the results were compared with the calculation data. The details, including the strength and deformation of particular turbine elements, are discussed in the paper. The dynamic behaviour of the turbogenerator rotor system was also examined. The changes of a turbine inlet pressure and rotor speed in the case of varying turbine power, emergency shutdown and blackout were measured and presented in the paper in different working conditions.
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Performance Evaluation of Control Plane Functions in ASON/GMPLS Architecture
- Sylwester Kaczmarek
- Magdalena Młynarczuk
- Paweł Zieńko
It is assumed that demands of information society could be satisfied by architecture ASON/GMPLS comprehended as Automatically Switched Optical Network (ASON) with Generalized Multi-Protocol Label Switching (GMPLS) protocols. Introduction this solution must be preceded performance evaluation to guarantee society expectations. Practical realization is expensive and simulations models are necessary to examine standardized propositions. This paper is devoted to the simulation results of ASON/GMPLS architecture control plane functions in OMNeT++ discrete event simulator. The authors make an effort to explore call/connection set-up time, connection release time in a single domain of ASON/GMPLS architecture.
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Performance of lubricated sliding contact in magnetic field
- Tadeusz Stolarski
- Y. Makida
Results of experimental studies concerning theinfluence of permanent magnetic field on wear of lubricatedsliding contact operating at short stroke and highfrequency are presented. It was found that horizontalmagnetic is affecting performance of the contact. Thejagged delamination regions produced in the presence of amagnetic field can be regarded as easily undergoing oxidisationbecause oxygen is readily adsorbed there. Magneticfield is likely to intensify the abrasive action by wearparticles and mitigate wear of the plate specimen. It ispostulated that all these effects are caused by the influenceof magnetic field on the electrical charge of the wornsurface created on Si3N4 ball.
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Performance of thermally balanced photovoltaic module
- Michał Modzelewski
- Ewa Klugmann-Radziemska
Intensywność procesu wymiany ciepła na powierzchni modułu fotowoltaicznego ma istotny wpływ na osiąganą przez obciążone ogniwa temperaturę i zależy od zastosowanych materiałów i konstrukcji modułu. Ilość energii elektrycznej wytworzonej przez obciążony moduł fotowoltaiczny spada, gdy mechanizmy promieniowania i konwekcji są zaburzone ze względu na przepływ ciepła w składowych warstwach podłoża. Wartości pojemności cieplnej i opory cieplne poszczególnych warstw modułu fotowoltaicznego są odpowiedzialne za dynamikę procesu wymiany ciepła pomiędzy powierzchnią a otaczającym powietrzem. Przedstawiono analizę wymiany ciepła przez promieniowanie i konwekcję od termicznie zrównoważonego modułu fotowoltaicznego. Omówiono czynniki, które ograniczają przepływ ciepła z modułu PV.
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Perovskites in Solid Oxide Fuel Cells
- Maria Gazda
- Piotr Jasiński
- Bogusław Kusz
- Beata Bochentyn
- Katarzyna Gdula-Kasica
- Tomasz Lendze
- Weronika LEWANDOWSKA-Iwaniak
- Aleksandra Dorota Mielewczyk-Gryń
- Sebastian Molin
Przeglądowa publikacja dotycząca wykorzystania ceramicznych materiałów perowskitowych w tlenkowych ogniwach paliwowych.
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