14 research outputs found
Changes of Vistula River channels pattern caused by W艂oc艂awek Dam functioning based on the analysis of aerial photographs
Wielokorytowy system fluwialny dolnej Wis艂y, z korytem g艂贸wnym typu roztokowego, jest przyk艂adem transformacji z jednokorytowego systemu piaskodennej rzeki roztokowej do systemu wielokorytowego. Transformacja ta zachodzi obecnie pod silnym wp艂ywem antropopresji wywo艂anej najpierw przeprowadzon膮 regulacj膮 koryta, a nast臋pnie oddzia艂ywaniem stopnia wodnego we W艂oc艂awku. Zar贸wno powy偶ej, jak i poni偶ej zbiornika zaporowego utworzonego w wyniku spi臋trzenia rzeki zaobserwowano spadek liczby form korytowych i mi臋dzykorytowych. Obszary mi臋dzykorytowe w wyniku zanikania bocznych ramion zosta艂y w艂膮czone w obszar r贸wniny zalewowej, a utrwalone ro艣linno艣ci膮 mi臋dzykorytowe wyspy zwi臋ksza艂y swoj膮 powierzchni臋ewoluuj膮c w kierunku obszar贸w mi臋dzykorytowych. Jednocze艣nie zmniejszy艂a si臋 liczba i powierzchnia odsyp贸w piaszczystych. Efektem proces贸w fluwialnych przebiegaj膮cych w warunkach oddzia艂ywania budowli hydrotechnicznych jest powolne utrwalanie si臋 wielokorytowego systemu fluwialnego, kt贸ry w odr贸偶nieniu od klasycznej rzeki anastomozuj膮cej, kt贸rej koryta rozdzielaj膮 obszary mi臋dzykorytowe, mo偶na okre艣li膰 jako rzek臋 rozga艂臋zion膮 (anabranching)
5-Deazaalloxazine as photosensitizer of singlet oxygen and potential redox-sensitive agent
Flavins are a unique class of compounds that combine the features of singlet oxygen generators and redox-dependent fluorophores. From a broad family of flavin derivatives, deazaalloxazines are significantly underdeveloped from the point of view of photophysical properties. Herein, we report photophysics of 5-deazaalloxazine (1a) in water, acetonitrile, and some other solvents. In particular, triplet excited states of 1ain water and in acetonitrile were investigated using ultraviolet-visible (UV-Vis) transient absorption spectroscopy. The measured triplet lifetimes for 1a were all on the microsecond time scale (approximate to 60 mu s) in deoxygenated solutions. The quantum yield of S-1 -> T-1 intersystem crossing for 1ain water was 0.43 based on T1 energy transfer from 1a to indicaxanthin (5) acting as acceptor and on comparative actinometric measurements using benzophenone (6). 1a was an efficient photosensitizer for singlet oxygen in aerated solutions, with quantum yields of singlet oxygen in methanol of about 0.76, compared to acetonitrile similar to 0.74, dichloromethane similar to 0.64 and 1,2-dichloroethane similar to 0.54. Significantly lower singlet oxygen quantum yields were obtained in water and deuterated water (Phi(Delta)similar to 0.42 and 0.44, respectively). Human red blood cells (RBC) were used as a cell model to study the antioxidant capacity in vitro and cytotoxic activity of 1a. Fluorescence-lifetime imaging microscopy (FLIM) data were analyzed by fluorescence lifetime parameters and distribution for different parts of the emission spectrum. Comparison of multidimensional fluorescent properties of RBC under physiological-like and oxidative-stress conditions in the presence and absence of 1a suggests its dual activity as probe and singlet-oxygen generator and opens up a pathway for using FLIM to analyze complex intracellular behavior of flavin-like compounds. These new data on structure-property relationship contribute to the body of information required for a rational design of flavin-based tools for future biological and biochemical applications.National Science Centre, Poland 2017/27/B/ST4/02494 (OPUS), NCN CEUS-UNISONO 2020/02/Y/ST4/00042, 2018/29/B/ST4/01498 (Opus), POIR.04.04.00-00-441F/17-00, Grant Agency of the Czech Republic 2013/08/T/ST4/00640 (Etiuda), Foundation for Polish Science 21-14200K, Smart Growth Operational Programme 2014-2020 POIR.04.02.00-00-C004/19-00, Ministry of Science and Higher Education, Poland DIR/WK/2018/06info:eu-repo/semantics/publishedVersio
Evaluating effects of dam operation on flow regimes and riverbed adaptation to those changes
Lithological features and grain size distribution of W艂oc艂awek Reservoir bottom deposits
Distribution of the bottom deposits and accumulation dynamics in the Wloclawek Reservoir (central Poland)
Nuclear Power in Poland鈥檚 Energy Transition
This article presents an analysis of the future role of nuclear energy in Poland鈥檚 path to a low-carbon energy transition. The arguments in favor of implementing nuclear power are to be found on three levels: energy security, economic competitiveness and energy efficiency, and lastly, limited environmental impact. In the process of creating this study, the methodology in the field of security sciences was used, including its interdisciplinary approach. Theoretical methods were used, e.g., critical analysis of scientific sources and comparison of statistical data and empirical methods, e.g., document analysis, comparative analysis. The article is based on an analysis of the literature on the subject, applicable legal acts, and government strategies in the field of energy security. The article contains the results of research no. BS.21.6.13 carried out by a research team from the Pomeranian Academy in S艂upsk that allowed to indicate the probable directions of transformation of the energy sector in Poland in the next decade