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991.
Milan Kráčalík Jana Mikešová Rudolf Puffr Josef Baldrian Ralf Thomann Christian Friedrich 《Polymer Bulletin》2007,58(1):313-319
Summary Formation of physical network in PET/organoclay nanocomposites leads to significant improvement of processing and utility
properties. The state of dispersion of silicate platelets in PET by melt mixing depends on shear forces as well on surface
chemical treatment of the filler. The level of dispersion was determined by X-ray diffraction analysis and transmission electron
microscopy. Melt rheology was used to examine the presence of network particles. It was shown that the addition of 5 wt. %
of organo-modified montmorillonite into recyclate leads to a 3D network structure with secondary plateau of G’ at lowest frequencies. XRD and TEM experiments supported the conclusion. 相似文献
992.
ABSTRACTThe capability of ozone to reduce the hazardous impact of environmentally persistent antibiotic tiamulin in term of toxicity reduction and enhancement of biodegradability was investigated. Different ozone doses were applied but ozonation was not effective enough to increase the biodegradability of tiamulin in the aqueous phase. The opposite effect was observed in anaerobic digestion experiments, where ozonation as a pretreatment step of antibiotic-contaminated sludge detoxify tiamulin and improves biogas production for 75%. As confirmed by 1H NMR and HPLC-HRMS analyses, the tiamulin molecule completely reacts with ozone at low ozone/COD molar ratio of 0.03, primarily attacking the vinyl double bond with further oxidation of sulfur and nitrogen atom, and gradual decomposition of tiamulin skeleton. 相似文献
993.
The pK a and the maximum solubility values of cholic, deoxycholic salts and their oxo-derivatives have been measured by the method of potentiometric titration. In the monomer phase (under the critical micellar concentration, CMC), the bile salts have different pK a values, as a result of their structural differences (the number of hydroxyl and oxo groups in the steroid skeleton) and different hydration properties of the acid anions. In the micellar phase (above the CMC), the bile salts have higher pK a values than in the monomer phase (under the CMC). This increase in the pK a values is greater in more hydrophobic bile salts (cholate and deoxycholate), than in less hydrophobic oxo derivatives, which can be explained by the different aggregation numbers of these bile salts. The oxo-derivatives are more likely to form dimeric micelles, where the carboxylic groups are situated on the two sides of the micelle, not causing any electrostatic repulsion. In the more hydrophobic bile salts, aggregation numbers are higher, which causes electrostatic repulsion of the nearby situated carboxylic anions and consequential protonation of these anions (which leads to the stabilization of the micelle). The maximum solubility values are higher for the oxo-derivatives. If the steroid skeleton of the bile salt is more hydrophobic, the capacity to solubilize the unionized bile acid is higher, i.e. a smaller amount of the bile acid anion is needed for the solubilization of the bile acid monomer. The oxo-derivatives are less hydrophobic, but alongside their hydrophobicity, the structure of the micelle determines the solubilization capacities. 相似文献
994.
Cécile Santos Frédéric Rogriguez Virginie Garcia Daniela Moravčíková Dr. Dušan Berkeš Prof. Adam Daïch Prof. Thierry Levade Dr. Cécile Baudoin‐Dehoux Dr. Stéphanie Ballereau Dr. Yves Génisson 《Chembiochem : a European journal of chemical biology》2014,15(17):2522-2528
A highly compartmentalized enzymatic network regulates the pro‐apoptotic and proliferative effects of sphingolipids. Over‐conversion of ceramide (Cer) correlates with insensitivity to apoptosis signaling (in response to chemotherapy) and to drug resistance of cancer cells. De novo sphingomyelin biosynthesis relies on non‐vesicular ceramide trafficking by the CERT (CERamide Transfer) protein. Therefore, blocking CERT transfer, thus leading to increased intracellular ceramide availability, represents a potential anticancer strategy. Our study is based on the implementation of an in vitro binding assay, supported by in silico molecular docking. It constitutes the first attempt to explore at the molecular level for the identification of novel CERT ligands. This approach is the first step toward in silico design and optimization of CERT inhibitor candidates, potentially relevant as innovative ceramide‐transfer‐targeting therapeutic agents. 相似文献
995.
Improvement of poly(lactic acid)/polyamide 6 (PLA/PA6) miscibility is approached by reactive compatibilization with using different reactive agents. Specifically, compatibilizing efficiency of commercially available Joncryl ADR-4368 (Joncryl) and free-radical initiator 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane (L101) is compared to that of laboratory synthesized compatibilizers (poly(lactic acid) grafted with itaconic anhydride (PLA-g-IAH) and poly(itaconic anhydride) (PIAH) by online rheology monitoring in internal mixer and oscillatory rheometer. The change of morphology and particle-size distribution is evaluated by scanning electron microscopy (SEM), the extent of PLA-PA6 miscibility is determined by differential scanning calorimetry (DSC), and newly formed polymer phases are identified by high-resolution thermogravimetric analysis (HR-TGA) and solvent extraction in formic acid. Although Joncryl exhibits the most promising results in PLA-PA6 compatibility, other compatibilizers also exhibit specific benefits for PLA/PA6 blend or individual polymers. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48005. 相似文献
996.
Dr. Marta Gozzi M.Sc. Blagoje Murganic Dijana Drača John Popp Dr. Peter Coburger Prof. Dr. Danijela Maksimović-Ivanić Prof. Dr. Sanja Mijatović Prof. Dr. Evamarie Hey-Hawkins 《ChemMedChem》2019,14(24):2061-2074
The role of autophagy in cancer is often complex, ranging from tumor-promoting to -suppressing effects. In this study, two novel hybrid molecules were designed, containing a ruthenacarborane fragment conjugated with a known modulator of autophagy, namely a quinoline derivative. The complex closo-[3-(η6-p-cymene)-1-(quinolin-8-yl-acetate)-3,1,2-RuC2B9H10] ( 4 ) showed a dual mode of action against the LN229 (human glioblastoma) cell line, where it inhibited tumor-promoting autophagy, and strongly inhibited cell proliferation, de facto blocking cellular division. These results, together with the tendency to spontaneously form nanoparticles in aqueous solution, make complex 4 a very promising drug candidate for further studies in vivo, for the treatment of autophagy-prone glioblastomas. 相似文献
997.
998.
Synthesis and characterization of interpenetrating polymer network based on sodium alginate and methacrylic acid and potential application for immobilization of TiO2 nanoparticles 下载免费PDF全文
Marija Lučić Škorić Nedeljko Milosavljević Maja Radetić Zoran Šaponjić Marija Radoičić Melina Kalagasidis Krušić 《Polymer Engineering and Science》2015,55(11):2511-2518
An interpenetrating polymer network (IPN) based on the sodium alginate (A) and partially neutralized poly(methacrylic acid) (MAA) was prepared by free radical polymerization followed by additional cross‐linking of sodium alginate with calcium ions. Obtained material (A/MAA IPN) was characterized by FTIR spectroscopy, thermogravimetric analysis, scanning electron microscopy, and rheological measurements. Swelling behavior of synthetized IPN has been also investigated. TiO2 nanoparticles (TiO2 NPs) were immobilized onto A/MAA IPN by dip‐coating method and obtained TiO2/IPN nanocomposite was used for removal of the methylene blue (MB) from aqueous solution. The photodegradation (under illumination) and sorption (in the dark) processes for dye removal were monitored through decrease of dye concentration in the solution by UV/VIS spectrometer. The TiO2/IPN nanocomposite sorbed approximately 93% of the MB from a 10 mg L?1 MB solution in the dark, but no degradation occurred. Likewise, more than 93% of dye was removed after 8 h of illumination. However, after 24 h of illumination, the samples were discolored indicating that dye molecules were successfully degraded. Thus, the TiO2/IPN nanocomposite could be utilized in the photodegradation–sorption process for the abatement of pollutants in water. POLYM. ENG. SCI., 55:2511–2518, 2015. © 2015 Society of Plastics Engineers 相似文献
999.
Aleksandar Radojković Danijela Luković Golić Jovana Ćirković Zorica Marinković Stanojević Damir Pajić Filip Torić Aleksandra Dapčević Predrag Vulić Zorica Branković Goran Branković 《Ceramics International》2018,44(14):16739-16744
Bulk ceramic samples of BiFeO3 were light doped (up to 1%) with Nb5+ in the place of Fe3+ (B-site doping) and their multiferroic properties were investigated using XRD, SEM, polarization (PMTS) and magnetization (SQUID) techniques. It is shown that even the small percentages of doping can notably change electric and magnetic behavior. Electric conductivity differs by two orders of magnitude between samples doped with 0.2% and 1% Nb. The ferroelectric behavior strongly depended on conduction mechanism, and transition from space-charge-limited current (SCLC) conduction to trap-filled limited (TFL) conduction regime reflected on a change in hysteresis patterns, particularly for the samples with 0.2% and 0.5% Nb. Separation of ZFC-FC magnetization curves occurred for all Nb concentrations and increased with Nb doping. Weak ferromagnetic behavior and the increase of remnant magnetization with Nb concentration was observed from the hysteresis measurements. Coercive field changed drastically compared to the pure BiFeO3, namely, the sample with 1% Nb exhibited very high coercive magnetic field of ~ 10?kOe. 相似文献
1000.
Experimental and theoretical consideration of the factors influencing cationic pollutants retention by seashell waste 下载免费PDF全文