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101.
Chlorobisphenolic epoxy resins in crystalline form, e.g., bisglycidyl ether of 2,2-bis(p-hydroxyphenyl)-1,1,1-trichloroethane (BGECBP) and the system sulfur–N-cyclohexyl-2-benzothiazolesulfonamide were used as crosslinking agents for vulcanization of butadiene–styrene and butadiene–acrylonitrile rubber. The density of crosslinking was determined by the equilibrium swelling method and on the basis of the Mooney-Rivlin equation which gives the relation between stress and elongation. The dynamic properties, namely, G′ and G″ and mechanical loss factor δ, were determined. On the basis of these results, mechanisms for the crosslinking reaction were advanced, the activation energy was determined, and comparisons between crosslinking rates by different systems were made. It was found that vulcanizates crosslinked by BGECBP possess higher heat aging resistance and lower glass transition temperatures in comparison with those crosslinked by means of sulfur in the presence of N-cyclohexyl-2-benzothiazolesulfonamide. 相似文献
102.
Nitrogen base fractions were prepared from a heavy coal-derived liquid via two commonly accepted laboratory procedures and partially characterized. Significant differences in the composition of the two fractions suggest strongly that extreme caution should be exercised in interpreting and comparing the results of base characterization studies in which different base isolation procedures are used. 相似文献
103.
Perfectly Wetting Mixtures of Surfactants from Renewable Resources: The Interaction and Synergistic Effects on Adsorption and Micellization 下载免费PDF全文
This paper presents a study of the surface properties of mixtures of surfactants originating from renewable sources, i.e., alkylpolyglucoside (APG), ethoxylated fatty alcohol (AE), and sodium soap (Na soap). The main objective was to optimize the surfactant ratio which produces the highest wetting properties during the analysis of the solution of the individual surfactants, two- and three-component mixtures, and at different pH values. The results showed the existence of a synergistic effect in lowering the interfacial tension, critical micelle concentration and the formation of mixed micelles in selected solutions. We found that best wetting properties were measured for the binary AE:APG mixtures. It has been demonstrated that slightly lower contact angles values were observed on Teflon and glass surfaces for the AE:APG:soap mixtures but the results were obtained for higher concentration of the components. In addition, all studied solutions have very good surface properties in acidic, basic and neural media. However, the AE:soap (molar ratio of 1:2), AE:APG (2:1) and AE:APG:soap (1:1:1) compositions improved their wetting power at pH 7 on the aluminium and glass surfaces, as compared to solutions at other pH values tested (selected Θ values close to zero—perfectly wetting liquids). All described effects detected would allow less surfactant to be used to achieve the maximum capacity of washing, wetting or solubilizing while minimizing costs and demonstrating environmental care. 相似文献
104.
A hybrid sorbent material for removal of hydrogen sulfide from air was developed. The material is based on activated carbon and iron compounds obtained from waste iron(II) sulfate(VI) heptahydrate. The iron salt is deposited on the carbonaceous support and subjected to oxidation (Fe2+ to Fe3+) using atmospheric oxygen under alkaline conditions. An effect of H2O2 addition to the process on the composition of the resultant material was also examined. X-ray diffraction (XRD) analyses confirmed easy conversion of waste FeSO4·7H2O to iron oxides Fe3O4 and FeOOH. The activated carbon supporting iron oxides revealed a higher efficiency in H2S elimination from air compared to the commercial activated carbon, without any modification. 相似文献
105.
Aneta Kaczor Nikoletta Szemerédi Dr. Katarzyna Kucwaj-Brysz Dr. Monika Dąbrowska Dr. Małgorzata Starek Dr. Gniewomir Latacz Dr. Gabriella Spengler Prof. Jadwiga Handzlik 《ChemMedChem》2021,16(15):2386-2401
ABCB1 modulation is an interesting strategy in the search for new anticancer agents that can overcome multidrug resistance (MDR). Hence, 17 new 5-arylideneimidazolones containing an amine moiety, as potential ABCB1 inhibitors, were designed, synthesized, and investigated. The series was tested in both parental (PAR) and multidrug-resistant (MDR) ABCB1-overexpressing T-lymphoma cancer cells using cytotoxicity assays. The ABCB1-modulating activity was examined in rhodamine 123 accumulation tests, followed by Pgp-Glo™ Assay to determine the influence of the most active compounds on ATPase activity. Lipophilic properties were assessed both, in silico and experimentally (RP-TLC). Pharmacophore-based molecular modelling toward ABCB1 modulation was performed. The studies allowed the identification of anticancer agents (p-fluorobenzylidene derivatives) more potent than doxorubicin, with highly selective action on MDR T-lymphoma cells (selectivity index >40). Most of the investigated compounds showed ABCB1-modulating action; in particular, two 5-benzyloxybenzylidene derivatives displayed activity nearly as strong as that of tariquidar. 相似文献
106.
Marta Krychowiak-Manicka Mirosawa Krauze-Baranowska Sylwia Godlewska Zbigniew Kaczyski Aleksandra Bielicka-Giedo Natalia Grzegorczyk Magdalena Narajczyk Joanna E. Frackowiak Aleksandra Krolicka 《International journal of molecular sciences》2021,22(9)
Carnivorous plants are exemplary natural sources of secondary metabolites with biological activity. However, the therapeutic antimicrobial potential of these compounds is limited due to intrinsic resistance of selected bacterial pathogens, among which Pseudomonas aeruginosa represents an extreme example. The objective of the study was to overcome the intrinsic resistance of P. aeruginosa by combining silver nanoparticles (AgNPs) with secondary metabolites from selected carnivorous plant species. We employed the broth microdilution method, the checkerboard titration technique and comprehensive phytochemical analyses to define interactions between nanoparticles and active compounds from carnivorous plants. It has been confirmed that P. aeruginosa is resistant to a broad range of secondary metabolites from carnivorous plants, i.e., naphthoquinones, flavonoids, phenolic acids (MBC = 512 µg mL−1) and only weakly sensitive to their mixtures, i.e., extracts and extracts’ fractions. However, it was shown that the antimicrobial activity of extracts and fractions with a significant level of naphthoquinone (plumbagin) was significantly enhanced by AgNPs. Our studies clearly demonstrated a crucial role of naphthoquinones in AgNPs and extract interaction, as well as depicted the potential of AgNPs to restore the bactericidal activity of naphthoquinones towards P. aeruginosa. Our findings indicate the significant potential of nanoparticles to modulate the activity of selected secondary metabolites and revisit their antimicrobial potential towards human pathogenic bacteria. 相似文献
107.
Marta Izabela Jonas Alina Kurylowicz Zbigniew Bartoszewicz Wojciech Lisik Maurycy Jonas Zbigniew Wierzbicki Andrzej Chmura Piotr Pruszczyk Monika Puzianowska-Kuznicka 《International journal of molecular sciences》2015,16(10):25817-25830
Excess adiposity is associated with chronic inflammation, which takes part in the development of obesity-related complications. The aim of this study was to establish whether subcutaneous (SAT) or visceral (VAT) adipose tissue plays a major role in synthesis of pro-inflammatory cytokines. Concentrations of interleukins (IL): 1β, 6, 8 and 15 were measured at the protein level by an ELISA-based method and on the mRNA level by real-time PCR in VAT and SAT samples obtained from 49 obese (BMI > 40 kg/m2) and 16 normal-weight (BMI 20–24.9 kg/m2) controls. IL-6 and IL-15 protein concentrations were higher in SAT than in VAT for both obese (p = 0.003 and p < 0.0001, respectively) and control individuals (p = 0.004 and p = 0.001, respectively), while for IL-1β this was observed only in obese subjects (p = 0.047). What characterized obese individuals was the higher expression of IL-6 and IL-15 at the protein level in VAT compared to normal-weight controls (p = 0.047 and p = 0.016, respectively). Additionally, obese individuals with metabolic syndrome had higher IL-1β levels in VAT than did obese individuals without this syndrome (p = 0.003). In conclusion, concentrations of some pro-inflammatory cytokines were higher in SAT than in VAT, but it was the increased pro-inflammatory activity of VAT that was associated with obesity and metabolic syndrome. 相似文献
108.
Jekaterina Hermane Ilona Bułyszko Dr. Simone Eichner Dr. Florenz Sasse Wera Collisi Prof. Dr. Antti Poso Emilia Schax Dr. Johanna‐Gabriela Walter Prof. Dr. Thomas Scheper Dr. Klaus Kock Prof. Dr. Christian Herrmann Dr. Pooyan Aliuos Prof. Dr. Günter Reuter Priv.‐Doz. Dr. Carsten Zeilinger Prof. Dr. Andreas Kirschning 《Chembiochem : a European journal of chemical biology》2015,16(2):302-311
Streptomyces hygroscopicus is a natural producer of geldanamycin. Mutasynthetic supplementation of an AHBA‐blocked mutant with all possible monofluoro 3‐aminobenzoic acids provided new fluorogeldanamycins. These showed strong antiproliferative activity and inhibitory effects on human heat shock protein Hsp90. Binding to Hsp90 in the low nanomolar range was determined from molecular modelling, AFM analysis and by calorimetric studies. 相似文献
109.
Martino Di Serio Riccardo Tesser Vincenzo Russo Rosa Turco Rosa Vitiello Yongqiang Sun Wiesław Hreczuch 《Journal of surfactants and detergents》2015,18(5):913-918
The intermediates for the production of nonionic surfactants can be derived from petrochemicals and/or from renewable raw materials. In both, the role of catalysis is fundamental. In this paper the main results reported in the literature related with the catalysis for ethoxylation of fatty esters will be reviewed. The main open challenges for these technologies will be outlined. 相似文献
110.
Measurements of the surface tension of aqueous solution of mixtures of sodium dodecyl sulfate (SDDS) with methanol and ethanol
in SDDS concentration range from 10−5 to 10−2 M and mixtures of sodium hexadecyl sulfonate (SHS) with methanol and ethanol at SHS concentration from 10−5 to 8 × 10−4 M and for methanol and ethanol from 0 to 21.1 and, 11.97 M, respectively, were carried out at 293 K. Moreover, the surface
tension of aqueous solution mixtures of SDDS with propanol in the concentration range from 0 to 6.67 M taken from the literature
was also considered. The results obtained indicate that it is possible to describe the relationship between the surface tension
and molar concentration or molar fraction of alcohol by Szyszkowski and Connors equations. However, the Fainerman and Miller
equation allows us to predict the isotherm of the surfactant tension at constant anionic surfactants concentration at which
their molecules are present in the solution in the monomeric form if the molar area of surfactants and alcohols can be determined.
Based on the surface tension isotherms, the Gibbs surface excess of anionic surfactants and alcohols concentration at water–air
interface was determined and then recalculated for Guggenheim-Adam surface excess concentration of these substrates, and next
the molar fraction of alcohols and surfactants in the surface layer was determined. These molar fractions were discussed with
regard to surfactant and alcohol standard free energy of adsorption at the water–air interface determined from Langmuir and
Aronson and Rosen equations. The standard free energy of adsorption determined in these ways was compared to that deduced
on the basis of pC20 and Lifshitz van der Waals-components of the anionic surfactant and alcohol tails. 相似文献