42 research outputs found

    Magnetic particles with polymeric shells bearing cholesterol moieties sensitize breast cancer cells to low doses of doxorubicin

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    One of the promising strategies for improvement of cancer treatment is application of a combination therapy. The aim of this study was to investigate the anticancer activity of nanoformulations containing doxorubicin and iron oxide particles covered with polymeric shells bearing cholesterol moieties. It was postulated that due to high affinity to cell membranes, particles comprising poly(cholesteryl acrylate) can sensitize cancer cells to doxorubicin chemotherapy. The performed analyses revealed that the developed systems are effective against the human breast cancer cell lines MCF-7 and MDA-MB-231 even at low doses of the active compound applied (0.5 µM). Additionally, high compatibility and lack of toxicity of the tested materials against human red blood cells, immune (monocytic THP-1) cells, and cardiomyocyte H9C2(2-1) cells was demonstrated. Synergistic effects observed upon administration of doxorubicin with polymer–iron oxide hybrids comprising poly(cholesteryl acrylate) may provide an opportunity to limit toxicity of the drug and to improve its therapeutic efficiency at the same time

    First searches for optical counterparts to gravitational-wave candidate events

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    During the Laser Interferometer Gravitational-wave Observatory and Virgo joint science runs in 2009-2010, gravitational wave (GW) data from three interferometer detectors were analyzed within minutes to select GW candidate events and infer their apparent sky positions. Target coordinates were transmitted to several telescopes for follow-up observations aimed at the detection of an associated optical transient. Images were obtained for eight such GW candidates. We present the methods used to analyze the image data as well as the transient search results. No optical transient was identified with a convincing association with any of these candidates, and none of the GW triggers showed strong evidence for being astrophysical in nature. We compare the sensitivities of these observations to several model light curves from possible sources of interest, and discuss prospects for future joint GW-optical observations of this type

    FIRST SEARCHES FOR OPTICAL COUNTERPARTS TO GRAVITATIONAL-WAVE CANDIDATE EVENTS

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    During the LIGO and Virgo joint science runs in 2009-2010, gravitational wave (GW) data from three interferometer detectors were analyzed within minutes to select GW candidate events and infer their apparent sky positions. Target coordinates were transmitted to several telescopes for follow-up observations aimed at the detection of an associated optical transient. Images were obtained for eight such GW candidates. We present the methods used to analyze the image data as well as the transient search results. No optical transient was identified with a convincing association with any of these candidates, and none of the GW triggers showed strong evidence for being astrophysical in nature. We compare the sensitivities of these observations to several model light curves from possible sources of interest, and discuss prospects for future joint GW-optical observations of this type

    On k-closure operators in graphs. II

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    Determination of the laminar burning velocity of dust-air mixtures by applying the model of dust explosion in as closed vessel

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    W artykule przedstawiono wyniki oznaczania laminarnej szybkości spalania deflagracyjnego mieszanin pyłowo-powietrznych metodą pozwalającą na rutynowe wykonywanie tego typu oznaczeń. Po raz pierwszy metoda ta została zastosowana przez Dahoe'a (2000). Polega ona na wykorzystaniu pomiarów zmian ciśnienia w czasie wybuchu mieszaniny pyłowo-powietrznej w zamkniętej, sferycznej objętości oraz modelu wybuchu opracowanego z uwzględnieniem zasad zachowania masy, pędu i energii w ujęciu całkowym. Dopasowanie parametrów modelu do zmierzonych zmian ciśnienia pozwala na wyznaczenie laminarnej szybkości spalania w mieszaninie pyłowo-powietrznej. W artykule przedstawiono wyniki oznaczeń laminarnych szybkości spalania dwóch pyłów: lycopodium i skrobi kukurydzianej.The article describes the method of determining the laminar burning velocity of dust-air mixtures by use of experimental data from standardized tests. For the first time the method was applied by Dahoe (2000). Data on pressure development in a closed, spherical vessel were used as an input to the integral balance model of dust explosion. Pressure history predicted by the model was fitted to the experimental data with the laminar burning velocity as the model's parameter. The article presents the results obtained for two dusts: lycopodium and maize starch

    Injectory sealing and firming of rock mass in front of binding cross-cut and drilled through Andaluzia Fall Zone in ZG "Piekary" conditions

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    W ZG "Piekary" zaistniała potrzeba wykonania przekopu łączącego 1 w pokładzie 506 przez strefę uskoku andaluzyjskiego w granicach obszarów górniczych "Brzeziny IV" i "Rozbark II". W celu uniknięcia szeregu problemów i zwiększenia bezpieczeństwa podczas przechodzenia przekopu przez strefę zaburzoną tektonicznie, zaprojektowano wyprzedzające za pomocą cementacji uszczelnienie i wzmocnienie górotworu przed jego czołem z wykorzystaniem otworów iniekcyjnych wierconych za pomocą wiertnic.In ZG "Piekary" there was a necessity to undertake a binding cross-cut 1 in the seam 506 through the Andaluzia Fall Zone in the range of the mining area "Brzeziny IV" and "Rozbark II". In order to avoid several problems and to increase safety during undergoing the cross-cut through tectonically distributed zone, there was designed advancing by cementation, sealing and firming of a rock mass in front of its head, using injectory holes drilled by drills

    New acetylacetone-polymer modified nanoparticles as magnetically separable complexing agents

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    In this paper, we present two methods of synthesis of new bifunctional polymeric nanohybrids and their full characterization. These nanohybrids consist of a magnetic nanoparticle core and polymeric shell which possess the ability to complex metal ions and organic compounds. Synthesized materials exhibit superparamagnetic properties and can thus be easily separated from complex mixtures by using an external magnetic field (facile separation, purification and recyclability). Herein, the syntheses of three bifunctional monomers are presented. Each of them was used to prepare the homopolymeric shell and two types of copolymeric shells (using styrene as a comonomer) around the magnetite nanoparticles. A surface initiated RAFT/MADIX polymerization technique was employed to prepare polymeric shells. Afterwards, post-modification of azide functionalized polymeric shells using the Huisgen “click” reaction was performed. Finally, twelve types of nanohybrids were prepared and their physicochemical properties were investigated. Additionally, the ability of nanohybrids to complex lanthanides and spectroscopic properties of obtained materials were studied

    Effect of genotype, environment and their interaction on quality parameters of wheat breeding lines of diverse grain hardness

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    Understanding the contribution of genotype, environment and genotype-by-environment interaction to wheat grain quality facilitates the selection for quality in breeding programs. Stability of grain quality characteristics is an important requirement in the baking industry. We assessed 24 winter wheat genotypes with different grain hardness in multienvironment trials at four locations and two levels of fertilization in each location. Grain samples were analyzed for hardness, protein and starch content, and wet gluten content, Zeleny sedimentation value, alveograph parameter (W) and hectoliter weight. All parameters were evaluated on whole grains using the near infrared transmittance technique. Differences between hard and soft genotypes appeared to be significant, apart from grain hardness, for protein content, Zeleny test and alveograph parameter. Genotype was found to have a major influence only on grain hardness; for protein content, wet gluten and Zeleny sedimentation value environment prevailed the influence of genotype, and for starch content, alveograph W parameter and hectoliter weight both sources of variation had similar importance. Genotype-by-environment interaction was of smaller size relative to genotype and environment in terms of all the studied quality parameters. Stable genotypes predominate the breeding lines studied. Response of unstable genotypes to environmental conditions was nonlinear in most cases
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