1. Flower-like superhydrophobic surfaces fabricated on stainless steel as a barrier against corrosion in simulated acid rainRegina Fuchs-Godec, 2022, original scientific article Abstract: Functionalisation of the metal surface of low-carbon ferritic stainless steel (from hydrophilic to hydrophobic properties) was achieved by flower-like hierarchical structures on a steel substrate prepared by a low-cost immersion method. The flower-like structured hydrophobic layers on the steel substrate were obtained by immersing the samples in an ethanolic solution of stearic acid with the addition of various concentrations of expired vitamin E ((+)α-tocopherol). The stability and corrosion-inhibiting effect of the hierarchically structured (such as natural cornflower) hydrophobic layers were studied systematically during short and long immersion tests, 120 h (five days) in an acidic environment (pH = 3) using potentiodynamic measurements, electrochemical impedance spectroscopy and chronopotentiometry. The surfaces of the samples, their wettability, surface morphology and chemical composition were characterised by contact angle measurements, SEM, ATR-FTIR and EDAX. After 120 h of immersion, the inhibition efficiency of the flower-like structured hydrophobic layers on the steel substrate in the selected corrosion medium remained above 99%, and the hierarchical structure (flower-like structure) was also retained on the surface. Keywords: acid rain, corrosion, flower-like structure, inhibition, stainless steel Published in DKUM: 05.12.2024; Views: 0; Downloads: 2
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3. A monocarbonyl curcuminoid derivative inhibits the activity of human glutathione transferase A4-4 and chemosensitizes glioblastoma cells to temozolomideSteliana Tsouri, Evanthia Tselo, Georgios E. Premetis, Veronika Furlan, Panagiota D. Pantiora, Barbara Mavroidi, Dimitris Matiadis, Maria Pelecanou, Anastassios C. Papageorgiou, Urban Bren, Marina Sagnou, Nikolaos E. Labrou, 2024, original scientific article Keywords: chemosensitization, chemoresistance, curcumin, glioblastoma, human glutathione transferase A4-4, ellagic acid, monocarbonyl curcumin derivatives, GST inhibition, temozolomide sensitization Published in DKUM: 23.08.2024; Views: 66; Downloads: 5
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4. Monocarbonyl Curcumin Analogues as Potent Inhibitors against Human Glutathione Transferase P1-1Panagiota D. Pantiora, Veronika Furlan, Dimitris Matiadis, Barbara Mavroidi, Fereniki Perperopoulou, Anastassios C. Papageorgiou, Marina Sagnou, Urban Bren, Maria Pelecanou, Nikolaos E. Labrou, 2023, original scientific article Abstract: The isoenzyme of human glutathione transferase P1-1 (hGSTP1-1) is involved in multi-drug resistance (MDR) mechanisms in numerous cancer cell lines. In the present study, the inhibition potency of two curcuminoids and eleven monocarbonyl curcumin analogues against hGSTP1-1 was investigated. Demethoxycurcumin (Curcumin II) and three of the monocarbonyl curcumin analogues exhibited the highest inhibitory activity towards hGSTP1-1 with IC50 values ranging between 5.45 1.08 and 37.72 1.02 M. Kinetic inhibition studies of the most potent inhibitors demonstrated that they function as non-competitive/mixed-type inhibitors. These compounds were also evaluated for their toxicity against the prostate cancer cells DU-145. Interestingly, the strongest hGSTP1-1 inhibitor, (DM96), exhibited the highest cytotoxicity with an IC50 of 8.60 1.07 M, while the IC50 values of the rest of the compounds ranged between 44.59–48.52 M. Structural analysis employing molecular docking, molecular dynamics (MD) simulations, and binding-free-energy calculations was performed to study the four most potent curcumin analogues as hGSTP1-1 inhibitors. According to the obtained computational results, DM96 exhibited the lowest binding free energy, which is in agreement with the experimental data. All studied curcumin analogues were found to form hydrophobic interactions with the residue Gln52, as well as hydrogen bonds with the nearby residues Gln65 and Asn67. Additional hydrophobic interactions with the residues Phe9 and Val36 as well as – stacking interaction with Phe9 contributed to the superior inhibitory activity of DM96. The van derWaals component through shape complementarity was found to play the most important role in DM96-inhibitory activity. Overall, our results revealed that the monocarbonyl curcumin derivative DM96 acts as a strong hGSTP1-1 inhibitor, exerts high prostate cancer cell cytotoxicity, and may, therefore, be exploited for the suppression and chemosensitization of cancer cells. This study provides new insights into the development of safe and effective GST-targeted cancer chemosensitizers. Keywords: curcuminoids, curcumin analogues, human glutathione transferase P1-1 (hGSTP1-1), glutathione transferase, enzyme inhibition, multi-drug resistance Published in DKUM: 12.03.2024; Views: 288; Downloads: 13
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5. Aerobic digester design for the biodegradation of plant tannins in industrial wastewaterMarko Tramšek, Andreja Goršek, 2008, original scientific article Abstract: This paper describes aerobic digester design for the biodegradation of plant tannins in industrial wastewater. For optimal design, using the criterion of minimal total holding time, some experimental investigations into tannins' biodegradation rate in industrial wastewater were performed in the first part of this research. The chemical oxygen demand method (COD) was applied to follow the tannins degradation rate. The kinetic parameters of a supposed Aiba's inhibition kinetic model were determined using experimental data. In the second part of the study, equations for determining the optimal volumes of two in series connected aerobic digesters were established. Furthermore, a comparison is presented of volumes between one and two in series connected aerobic digester systems regarding wastewater volume flow rate, qV = 120 m3 d-1 and wastewater treatment efficiency, COD = 9 8%. Keywords: digester design, plant tannins, Aiba's inhibition kinetic model, aerobic digestion, industrial wastewater Published in DKUM: 31.05.2012; Views: 2113; Downloads: 67
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6. The aerobic biodegradation kinetics of plant tannins in industrial wastewaterMarko Tramšek, Andreja Goršek, Peter Glavič, 2006, original scientific article Abstract: This paper describes an experimental determination of the biodegradation rate for tannins present in industrial wastewater, after the extraction of chestnut chips. Experiments were performed in a laboratory aerobic reactor (Armfield) by using biomass from an existing industrial wastewater treatment plant. The outlet tannins concentration was determined under various processing conditions. Simultaneously, an optical microscope was used to monitor the mix of microbiological cultures in the biomass. On the basis of data obtained in experiments, non-linear regression was used to perform parametric analysis of various kinetic models, which took into account inhibition, as quoted in literature (Haldane, Edwards, Aiba, Luong). The statistical analysis, based on the P-criterion, F-criterion, adjusted coefficient of determination, Kolmogorov-Smirnov test and root mean squared error, showed that the biodegradation of plant tannins in industrial wastewater under selected conditions for aerobic digestion, can be most successfully described statistically by the Aiba's kinetic model. Keywords: plant tannins, susbtrate inhibition, kinetic models, statistic analysis, aerobic industrial wastewater digestion Published in DKUM: 31.05.2012; Views: 1996; Downloads: 51
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