Knowledge of the structure-activity relationship (SAR) allows for the possibility to design and synthesize new cationic amphiphiles with optimized antimicrobial activities for future development of new disinfectants, sanitizers or preservatives. The need to design and identify new compounds, possessing antimicrobial properties, results from the emergence of more resistant micro-organisms in our globalized society. Hitherto, most studies which analyse the biological activity of ionic liquids (ILs) investigate the effect of the cation, whereas the knowledge of the effect of the anion is limited. The present study confirms the existence of a strong relationship among structure, surface activity and biological action of imidazolium ionic liquids on bacteria and fungi. The dependence of the antimicrobial activity on chemical structure-chain length and anion type of 30 compounds was determined. The anion is an important structural element which partakes in the definition of the phyiscochemical properties of the IL, and in consequence the technological applications and mode of action of the compound. The introduction of a longer substituent on the imidazolium cation results in a lower minimal inhibitory concentration (MIC). Thus, antifungal and antibacterial activities were found to increase with chain length, very often up to a point exhibiting a cut-off effect at chain lengths of 16 or 18 for the imidazolium cation and the [Cl] anion. The efficiency of surface tension reduction circumscribed by the pC 20 and the relationship between antimicrobial activity and pC 20 is described herein. The relationship indicates an antimicrobial mode of action dependant on the surface activity of the molecule, inferring that surface activity may contribute to the cut-off effect in the biological activity of ILs.

A series of Ag-TiO 2 photocatalysts were obtained in microemulsion system (water/AOT/cyclohexane), using several Ag precursor amount ranging from 1.5 to 8.5 mol.%. The photocatalysts' characteristics by X-ray diffraction, STEM microscopy, UV-Vis spectroscopy, X-ray photoelectron spectroscopy, BET methods showed that a sample with the highest photo-and bioactivity had anatase structure, about 90 m 2 /g specific surface area, absorbed light for λ>400 nm and contained 1.64 at.% of silver (0.30 at.% of Ag 0 and 1.34 at.% of Ag 2 O) and about 13 at.% of carbon in the surface layer.The photocatalytic activity of the catalysts was estimated by measuring the decomposition rate of phenol in 0.21 mM aqueous solution under visible and ultraviolet light irradiation.The bioactivity of silver-doped titanium dioxide nanocomposites was estimated using

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Three structurally related oxathiolone fused chalcone derivatives appeared effective chemosensitizers, able to restore in part sensitivity to fluconazole of multidrug-resistant C. albicans strains. Compound 21 effectively chemosensitized cells resistant due to the overexpression of the MDR1 gene, compound 6 reduced resistance of cells overexpressing the ABC-type drug transporters CDR1/CDR2 and derivative 18 partially reversed fluconazole resistance mediated by both types of yeast drug efflux pumps. The observed effect of sensitization of resistant strains of Candida albicans to fluconazole activity in the presence of active compounds most likely resulted from inhibition of the pump-mediated efflux, as was revealed by the results of studies involving the fluorescent probes, Nile Red, Rhodamine 6G and diS-C3(3).

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AMG-148, an oxathiolone-fused chalcone derivative, exhibited in vitro antifungal activity against several strains of human pathogenic yeast, with minimum inhibitory concentration values within the range of 1-16 μg ml(-1) and a fungicidal effect was observed at higher concentrations. Presence of major drug-effluxing membrane proteins Cdr1p, Cdr2p or Mdr1p, did not affect substantially the fungistatic activity of this compound against clinical Candida albicans strains. Studies on the mode of action revealed that AMG-148 inhibited chitin and β(1→3)glucan biosynthesis and was in vitro an inhibitor of β(1→3)glucan synthase. Inhibition of chitin biosynthesis was responsible for fungistatic activity, while the fungicidal effect was a consequence of disturbance of β(1→3)glucan synthase function. The chalcone derivative may be a useful lead compound for the development of novel antifungal agents.

W artykule przedstawiono problematykę związaną z łączeniem cienkich blach ze stali ocynkowanej, które lutospawano ze stopem aluminium 5754. Złącza wykonano niskoenergetyczną metodą CMT na stanowisku zrobotyzowanym przy użyciu spoiw na bazie aluminium (AlSi5) oraz cynku (ZnAl15). Wyniki badań wizualnych i metalograficznych złączy zakładkowych potwierdzają ich wysoką jakość, bez śladów naruszenia powłoki cynkowej w pobliżu spoiny. Przedstawiono również wyniki wytrzymałości na ścinanie złączy zakładkowych w zależności od rodzaju użytego spoiwa. Wykazano, że użycie spoiwa o niższej temperaturze topnienia umożliwia uzyskanie złączy o większej wytrzymałości mechanicznej.

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