The antibacterial behavior of cationic polyelectrolytes is studied using model membrane experiments and in vitro bacterial investigations. The molecular interaction with lipid films is evaluated by the degree of penetration of the polymers into Langmuir monolayers of neutral or negatively charged lipids. The polymer/lipid interaction results in structural changes of the penetrated lipid layer visualized using AFM. The polymers are found to be effective in inhibiting the proliferation of E. coli, B. subtilis and S. aureus. The influence of the chemical structure on the functional behavior is related to the conformational properties. An optimum structure is identified on the basis of antibacterial and hemolytic tests as well as membrane‐destroying efficacy of the antimicrobial polymers.
Cyclic chalcone analogues (2–5) and their ferrocenyl counterparts (6–10) were synthesized and their logP and P388 cyctotoxity were investigated. The structures of the newly synthesized compounds were confirmed by IR 1H and 13NMR spectroscopy. Comparison of conjugation and stereochemistry of the respective derivatives showed similar characteristics compared to ones with some higher degree of conjugation in the ferrocenyl series. Comparison of logP of the ferrocenyl derivatives determined by a validated RP-TLC method showed the ferrocenyl derivatives to have higher logPTLC. The results demonstrate that the differences in three dimensional shape, conjugation and lipophilicity do not have strong influence on the P388 cytotoxicity of the investigated phenyl (1−5) and ferrocenyl (6−10) enones. 相似文献
A long-term radon concentration monitoring was carried out in the Pál-v?lgy cave, Budapest, Hungary, for 1.5 years. Our major goal was to determine the time dependence of the radon concentration in the cave to characterise the air exchange and define the most important environmental parameters that influence the radon concentration inside the cave. The radon concentration in the cave air was measured continuously by an AlphaGuard radon monitor, and meteorological parameters outside the cave were collected simultaneously. The air's radon concentration in the cave varied between 104 and 7776?Bq?m(-3), the annual average value was 1884±85?Bq?m(-3). The summer to winter radon concentration ratio was as high as 21.8. The outside air temperature showed the strongest correlation with the radon concentration in the cave, the correlation coefficient (R) was 0.76. 相似文献
In this paper, the performance of a previously developed classification system applied to pharmaceutical chromatographic analyses, is investigated. The separation of seven different drug substances from their respective impurities was studied. The chromatographic procedure for acetylsalicylic acid, clindamycin hydrochloride, buflomedil hydrochloride, chloramphenicol sodium succinate, nimesulide and phenoxymethylpenicillin was performed according to the corresponding European Pharmacopoeia (Ph. Eur.) monograph. The separation of dihydrostreptomycin sulphate was performed according to the literature. It is shown that the column ranking system is a helpful tool in the selection of a suitable column in these analyses. 相似文献
The water-soluble iron(III) complex of meso-tetra(4-sulfonatophenyl)porphine is oxidized by bromate in nearly neutral aqueous
solutions in an overall six-electron three-step consecutive reaction. Kinetics and mechanism of the reaction are described. 相似文献
Reaction of azolylacroleins with phosphoranes bearing a conjugated double bond was found to yield either azolyltrienes in a Wittig reaction, or to undergo cyclization to a dihydrobenzene containing the azole substituent. Transformation with an aza-Wittig reagent gave tetrazolylpyridines. The ambident reactivity was found to be dependent on the substituent of the phosphorane, which was rationalized by ab initio (DFT) calculation of the atomic charges of the reaction centres. 相似文献
The purpose of the study was to analyze the correlation between the quantity of eluted monomers from dental resin-based composite using reverse-phase HPLC and the degree of conversion (DC) using micro-Raman spectroscopy, and to evaluate the influence of the energy of polymerization delivered on the composite material and the applied resin layer thickness on these properties. There was direct proportion in degree of conversion and inverse proportion in monomer elution when the energy of light polymerization was increased from 20 to 40 J cm?2; however, further increase in energy density did not influence significantly the DC and the elution of monomers. Investigating the depth of cure significant differences could be measured both in DC and the elution of monomers. 1 mm layer increment up to 3 mm from the top led to 10 % decrease in DC and 30–35 % increase in monomer elution. Further increase in depth from 3 to 4 mm caused 30 % drop in DC and 55 % increase in the amount of leached monomers. The overall result of the findings indicates that direct correlation exists between DC of composite and the elution of unreacted monomers. 相似文献
6- and 7-thiocyanato derivatives of 6-demethoxythebaine were obtained by nucleophilic substitution and elimination reactions of 14-halogenated codeine tosylate. 相似文献
A short synthesis of some fused indole-heterocycles has been achieved via Pd-catalyzed cross-coupling reactions between azido-2-bromobenzene and arylboronic acids and subsequent thermally induced nitrene insertion. Additionally, 4-amino-α-carboline, a versatile intermediate toward grossularine analogs has also been prepared by Suzuki-Miyaura cross-coupling of 4-pivaloylaminopyridine-3-boronic acid with 2-bromoaniline, followed by simple functional group transformations. 相似文献