Wrocław University of Technology

About: Wrocław University of Technology is a education organization based out in Wrocław, Poland. It is known for research contribution in the topics: Laser & Computer science. The organization has 13115 authors who have published 31279 publications receiving 338694 citations.

Non-Isolated High-Gain Triple Port DC–DC Buck-Boost Converter With Positive Output Voltage for Photovoltaic Applications

Abstract: The solar PV based power generation systems are growing faster due to the depletion of fossil fuels and environmental concerns Combining PV panels and energy buffers such as battery through multi-port converter is one of the viable solutions to deal with the intermittency of PV power The goal of this paper is to design and analyze the proposed triple port DC-DC buck-boost converter for high step-up/step-down applications It has two unidirectional ports (port-1 and port-3) and one bi-directional port (port-2) for harnessing photovoltaic energy and charging the battery At port-1, the combined structure of buck and buck-boost converter is used with a particular arrangement of switches and inductors The step-up/step-down voltage conversion ratio is higher than the conventional buck-boost converter, and the polarity of the output voltage is maintained positive The battery is added at the bi-directional port, for the storage of energy through the bi-directional boost converter The switches operate synchronously for most of the modes making the control strategy simple The characteristics and modes of operation along with a switching strategy, are elaborated Experimental results are presented which validate the agreement with the developed theoretical expectation

New Organoselenium Compounds Active against Pathogenic Bacteria, Fungi and Viruses

Abstract: Different N-substituted benzisoselenazol-3(2H)-ones, analogues of ebselen were designed as new antiviral and antimicrobial agents. We report their synthesis, chemical properties as well as study on biological activity against broad spectrum of pathogenic microorganisms (Staphylococcus aureus, Staphylococcus simulans, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Candida albicans, Aspergillus niger) and viruses (herpes simplex virus type 1 (HSV-1), encephalomyocarditis virus (EMCV), vesicular stomatitis virus (VSV)), in vitro. Most of them exhibited high activity against viruses (HSV-1, EMCV) and gram-positive bacteria strains (S. aureus, S. simulans), while their activity against gram-negative bacteria strains (E. coli, P. aeruginosa, K. pneumoniae) was substantially lower. Some of tested compounds were active against yeast C. albicans and filamentous fungus A. niger.

Selective prebiotic formation of RNA pyrimidine and DNA purine nucleosides

Abstract: The nature of the first genetic polymer is the subject of major debate1. Although the 'RNA world' theory suggests that RNA was the first replicable information carrier of the prebiotic era-that is, prior to the dawn of life2,3-other evidence implies that life may have started with a heterogeneous nucleic acid genetic system that included both RNA and DNA4. Such a theory streamlines the eventual 'genetic takeover' of homogeneous DNA from RNA as the principal information-storage molecule, but requires a selective abiotic synthesis of both RNA and DNA building blocks in the same local primordial geochemical scenario. Here we demonstrate a high-yielding, completely stereo-, regio- and furanosyl-selective prebiotic synthesis of the purine deoxyribonucleosides: deoxyadenosine and deoxyinosine. Our synthesis uses key intermediates in the prebiotic synthesis of the canonical pyrimidine ribonucleosides (cytidine and uridine), and we show that, once generated, the pyrimidines persist throughout the synthesis of the purine deoxyribonucleosides, leading to a mixture of deoxyadenosine, deoxyinosine, cytidine and uridine. These results support the notion that purine deoxyribonucleosides and pyrimidine ribonucleosides may have coexisted before the emergence of life5.

Langevin Picture of Subdiffusion with Infinitely Divisible Waiting Times

Abstract: In this paper we study a Langevin approach to modeling of subdiffusion in the presence of time-dependent external forces. We construct a subordinated Langevin process, whose probability density function solves the subdiffusive fractional Fokker-Planck equation. We generalize the results known for the Levy-stable waiting times to the case of infinitely divisible waiting-time distributions. Our approach provides a complete mathematical description of subdiffusion with time-dependent forces. Moreover, it allows to study the trajectories of the constructed process both analytically and numerically via Monte-Carlo methodology.