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131.
Magdalena Hasik Wincenty Turek Anna Nyczyk Edyta Stochmal Andrzej Bernasik Agnieszka Sniechota Agnieszka Sołtysek 《Catalysis Letters》2009,127(3-4):304-311
Composites of polyaniline (PANI) or polypyrrole (PPy) doped with chloride ions and Pt or Rh particles were prepared by chemical reduction of metal ions conducted in the presence of the polymers. Based on X-ray diffraction studies it was established that the composites contained metal nanoparticles (5–9 in size). However, according to SEM investigations metal particles were agglomerated (40 nm–1.1 μm in size). Redox activity of the composites in the catalytic isopropyl alcohol conversion was ca. ten times higher than the acid–base one. Pt dispersed in polymer matrices showed higher catalytic activity than Rh. PPy doped with chloride ions had a promoting effect on the activity of Pt catalysts. 相似文献
132.
Agnieszka Krawczyk-ebek Monika Dymarska Tomasz Janeczko Edyta Kostrzewa-Susow 《International journal of molecular sciences》2021,22(17)
Flavonoids, including chalcones, are more stable and bioavailable in the form of glycosylated and methylated derivatives. The combined chemical and biotechnological methods can be applied to obtain such compounds. In the present study, 2′-hydroxy-2-methylchalcone was synthesized and biotransformed in the cultures of entomopathogenic filamentous fungi Beauveria bassiana KCH J1.5, Isaria fumosorosea KCH J2 and Isaria farinosa KCH J2.6, which have been known for their extensive enzymatic system and ability to perform glycosylation of flavonoids. As a result, five new glycosylated dihydrochalcones were obtained. Biotransformation of 2′-hydroxy-2-methylchalcone by B. bassiana KCH J1.5 resulted in four glycosylated dihydrochalcones: 2′-hydroxy-2-methyldihydrochalcone 3′-O-β-d-(4″-O-methyl)-glucopyranoside, 2′,3-dihydroxy-2-methyldihydrochalcone 3′-O-β-d-(4″-O-methyl)-glucopyranoside, 2′-hydroxy-2-hydroxymethyldihydrochalcone 3′-O-β-d-(4″-O-methyl)-glucopyranoside, and 2′,4-dihydroxy-2-methyldihydrochalcone 3′-O-β-d-(4″-O-methyl)-glucopyranoside. In the culture of I. fumosorosea KCH J2 only one product was formed—3-hydroxy-2-methyldihydrochalcone 2′-O-β-d-(4″-O-methyl)-glucopyranoside. Biotransformation performed by I. farinosa KCH J2.6 resulted in the formation of two products: 2′-hydroxy-2-methyldihydrochalcone 3′-O-β-d-(4″-O-methyl)-glucopyranoside and 2′,3-dihydroxy-2-methyldihydrochalcone 3′-O-β-d-(4″-O-methyl)-glucopyranoside. The structures of all obtained products were established based on the NMR spectroscopy. All products mentioned above may be used in further studies as potentially bioactive compounds with improved stability and bioavailability. These compounds can be considered as flavor enhancers and potential sweeteners. 相似文献
133.
Kamiński M Niemczyk E Masaoka M Karbowski M Hallmann A Kedzior J Majczak A Knap D Nishizawa Y Usukura J Woźniak M Klimek J Wakabayashi T 《Microscopy research and technique》2004,64(3):255-258
Time-dependent changes in the cell death mode from apoptosis to necrosis were studied in cultured 143B cells treated with menadione, an anti-cancerous drug, excluding a possible involvement of "secondary necrosis." The population of apoptotic cells judged by FITC-Annexin V and propidium iodide (PI) double staining reached its maximum at 6 hours after 100 microM menadione treatment followed by an abrupt decrease thereafter, while that of necrotic cells continuously increased reaching 90% at 24 hours. Electron microscopically, cells attached to the culture dish at 6 hours after the treatment consisted of two different types of cells: cells with typical apoptotic features occupying the major population and those with condensed nuclei and swollen cytoplasm. Cells attached to the culture dish at 8 hours after the treatment consisted exclusively of those with condensed nuclei and swollen cytoplasm. Mitochondria in these cells showed various structural changes: those swollen to various degrees with deposition of flocculent densities, or those with highly condensed matrix. Distinct decreases both in intracellular levels of ATP and caspase-3-like activities and remarkable elevations of intracellular levels of superoxide, which were partly suppressed by NAD(P)H oxidase inhibitors, occurred at 6 hours after the treatment. These results may suggest that distinct increases of the intracellular level of superoxide derived from plasma membrane NAD(P)H oxidase besides that from mitochondria have triggered the transition of cell death mode from apoptosis to necrosis. Transition of highly condensed mitochondria to extremely swollen ones may reflect necrotic processes in menadione-treated cells. The present study strongly suggests that time-dependent study is essential using the electron microscopic technique to analyze detailed processes in the changes of the cell death mode. 相似文献
134.
Anna Winiarska-Mieczan Małgorzata Kwiecień Katarzyna Kwiatkowska Edyta Kowalczuk-Vasilev Bożena Kiczorowska 《Food Additives and Contaminants: Part B: Surveillance Communications》2018,11(3):223-228
The purpose of this survey was to estimate the safety of ready-to-eat infant foods in terms of Pb and Cd content. The studied samples were ready-to-eat infant products: dinners (n = 74), soups (n = 27) and desserts (n = 82) containing components of animal origin: meat and/or milk. Cd and Pb content was determined using a GF-AAS method. The analysed products contained 1.82–3.54 µg Pb and 1.32–1.50 µg Cd per kg. The content of Pb per kg of the product can be represented as dinners > soups > desserts, whereas the content of Cd was dinners > desserts > soups. The analysed ready-to-eat products could be regarded as safe, because they supply 12-month-old infants with Pb in an amount accounting for nearly 22% BMDL01 and Cd accounting for ca. 8.6% of the total weekly intake. 相似文献
135.
Xinmeng Tang Edyta Dzieminska Makoto Asahara A. Koichi Hayashi Nobuyuki Tsuboi 《International Journal of Hydrogen Energy》2018,43(18):9094-9109
To investigate the safety properties of high-pressure hydrogen discharge or leakage, an under-expanded hydrogen jet flow with a storage pressure of 82 MPa from a small jet orifice with a diameter of 0.2 mm is studied by three-dimensional (3D) numerical calculations. The full 3D compressible Navier-Stokes equations are utilized in a domain with a size of about 3 × 3 × 6 m which is discretized by employing an adaptive mesh refinement (AMR) technology to reduce the number of grid cells. By AMR, the local mesh resolutions can narrowly cover the Taylor microscale and direct numerical simulations (DNS) are performed. Both the instantaneous and mean hydrogen concentration distributions in the present jet are discussed. The instantaneous concentrations of hydrogen on the axis presents significant turbulent pulsating oscillations. The centerline value of the intensity of concentration fluctuation asymptotically comes to 0.23, which is in a good agreement with the existing experimental results. It substantiates the conclusion that the asymptotic centerline value of is independent of jet density ratio. The probability distributions function (PDF) of instantaneous axial agree approximately with the Gaussian distribution while skewing a little to the higher range. The time averaged hydrogen concentration along the radial directions can also be described as a Gaussian distribution. The axial of 82 MPa hydrogen jet tends to obey the distribution discipline approximated with where z is the axial distance from the nozzle and is the effective ejection diameter, which is consistent with the experimental results. In addition, the hydrogen tip penetration is found to be in a linear relationship with the square root of jet flow time . Meanwhile, the jet's velocity half-width approximately gains an linear relation with z which can be expressed as . 相似文献
136.
Edyta Janik-Karpinska Michal Ceremuga Magdalena Wieckowska Monika Szyposzynska Marcin Niemcewicz Ewelina Synowiec Tomasz Sliwinski Michal Bijak 《International journal of molecular sciences》2022,23(9)
T-2 toxin is produced by different Fusarium species, and it can infect crops such as wheat, barley, and corn. It is known that the T-2 toxin induces various forms of toxicity such as hepatotoxicity, nephrotoxicity, immunotoxicity, and neurotoxicity. In addition, T-2 toxin possesses a strong dermal irritation effect and can be absorbed even through intact skin. As a dermal irritant agent, it is estimated to be 400 times more toxic than sulfur mustard. Toxic effects can include redness, blistering, and necrosis, but the molecular mechanism of these effects still remains unknown. This in vitro study focused on the direct toxicity of T-2 toxin on human skin—fibroblast Hs68 cell line. As a result, the level of toxicity of T-2 toxin and its cytotoxic mechanism of action was determined. In cytotoxicity assays, the dose and time-dependent cytotoxic effect of T-2 on a cell line was observed. Bioluminometry results showed that relative levels of ATP in treated cells were decreased. Further analysis of the toxin’s impact on the induction of apoptosis and necrosis processes showed the significant predominance of PI-stained cells, lack of caspase 3/7 activity, and increased concentration of released Human Cytokeratin 18 in treated cells, which indicates the necrosis process. In conclusion, the results of an in vitro human skin fibroblast model revealed for the first time that the T-2 toxin induces necrosis as a toxicity effect. These results provide new insight into the toxic T-2 mechanism on the skin. 相似文献
137.
Edyta Symoniuk Aneta Łapińska Katarzyna Ratusz Małgorzata Wroniak 《European Journal of Lipid Science and Technology》2023,125(2):2200062
The study investigates the impact of operating parameters such as temperature (90, 100, 110, 120 °C), airflow rate (10, 15, 20 L h−1), and sample weight (3, 6, 9 g) on the oxidative stability of cold-pressed camelina and hemp seed oils using the Rancimat apparatus. Conducted analysis indicates a significant influence of temperature on oils' induction time. Moreover, higher airflows should be selected at high analysis temperatures. Based on the calculated parameters of the oxidation kinetics, it was shown that hemp oil has higher activation energy values than camelina oil. Response surface methodology (RSM) indicates that to minimize the determination time of camelina oil oxidation, the following analysis conditions should be selected: sample weight (SW) = 33.5 g, airflow (AF) = 20 L h−1, and temperature (T) = 120 °C. However, for hemp oil, these parameters should be SW = 5.56 g, AF = 15 L h−1, T = 120 °C. Sample mass does not significantly impact oils induction time, which depends mainly on the temperature and airflow. Practical applications: The conducted research shows that the parameters of the cold-pressed camelina and hemp oils oxidative stability have to be determined experimentally. The determined parameters for assessing the oxidative stability will reduce the analysis time and the possibility of interpolating the obtained result at different temperatures and analysis parameters. 相似文献
138.
Matthew B. Donnelly Mushita M. Munia Joris G. Keizer Yousun Chung A. M. Saffat-Ee Huq Edyta N. Osika Yu-Ling Hsueh Rajib Rahman Michelle Y. Simmons 《Advanced functional materials》2023,33(18):2214011
Controlling electron tunneling is of fundamental importance in the design and operation of semiconductor nanostructures such as field effect transistors (FETs) and quantum computing device architectures. The exponential sensitivity of tunneling with distance requires precise fabrication techniques to engineer the desired device dimensions to achieve the appropriate tunneling resistances/tunnel rates. This is particularly important for high fidelity spin readout and qubit exchange in quantum computing architectures. Here, it is shown by combining precision fabrication techniques with accurate atomistic modeling, predictive device design criteria are achieved at atomic length scales. Such a tool is useful when devices become more complex or have arbitrary shapes/geometries. In particular, in this study, atomic precision patterning of monolayer degenerately phosphorus-doped silicon tunnel junctions patterned by scanning tunnelling microscopy lithography and tight-binding non-equilibrium Green's function (TB-NEGF) modeling is combined to describe the dependence of tunnel junction resistance RT on junction length. An agreement with experiment to within a factor of 2 over 4 orders of magnitude in RT is found, and this model allows to accurately determine the barrier height V0 = 57.5 ± 1 meV and lateral seam sxy = 0.39 ± 0.01 nm in these nanoscale junctions. This study confirms the use of the TB-NEGF formalism to accurately model highly doped atomically precise tunnel junctions in silicon. Further applications of this model will enable improved device performance at the nanoscale. 相似文献