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91.
Dukovic G Balaz M Doak P Berova ND Zheng M McLean RS Brus LE 《Journal of the American Chemical Society》2006,128(28):9004-9005
We have found that racemic mixtures of chiral single-walled nanotubes (SWNTs) wrapped with d(GT)20 DNA oligomer exhibit circular dichroism (CD). We attribute the CD signal to induced CD arising from the coupling of transition moments of the SWNTs and the DNA. Although the nanotube mixture appears to contain both enantiomers in equal amounts, DNA-SWNT transition moment interaction is more constructive for one SWNT enantiomer over the other, resulting in an overall CD signal. 相似文献
92.
Anita Grozdanov Aleksandra Buzarovska Gordana Bogoeva‐Gaceva Emanuel Nedkov 《Journal of Polymer Science.Polymer Physics》2005,43(1):66-73
The kinetics of nonisothermal melting and the crystallization of polypropylene (PP) in polypropylene/carbon‐fiber (C/PP) composites were studied by differential scanning calorimetry with the Nedkov and Atanasov method. Characteristic parameters such as the lamellar thickness, the transport energy through the phase boundary, and the surface free energy were determined and analyzed. In nonisothermal melting, the nucleation effect of carbon fibers was confirmed by decreasing transport energy (79 and 41 kJ/mol for PP and C/PP, respectively) and surface free energy (8 × 10?4 and 7.9 × 10?5 J/m2 for PP and C/PP, respectively). Depending on the carbon‐fiber content, the lamellar thickness changed from 6.7 × 10?9 m to 9.05 × 10?9 m. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 66–73, 2005 相似文献
93.
Gordana Stojanovic 《Geometriae Dedicata》2006,123(1):1-10
We introduce (k,l)-regular maps, which generalize two previously studied classes of maps: affinely k-regular maps and totally skew embeddings. We exhibit some explicit examples and obtain bounds on the least dimension of a
Euclidean space into which a manifold can be embedded by a (k,l)-regular map. The problem can be regarded as an extension of embedding theory to embeddings with certain non-degeneracy conditions
imposed, and is related to approximation theory. 相似文献
94.
Bigović D Savikin K Janković T Menković N Zdunić G Stanojković T Djurić Z 《Natural product communications》2011,6(6):819-822
Flowers of Helichrysum plicatum were extracted under different experimental conditions, and their antioxidant activity was determined by DPPH radical scavenging assay. Extracts obtained with higher concentration of ethyl acetate (90% or 100%) were found to contain the greatest amount of total phenolics (> 250 mg gallic acid equivalents/g of dried extract), and high correlation between total phenolic content and antiradical activity was observed (r = -0.79). Based on the total phenolic content and antiradical activity, some extracts were selected for investigation of cytotoxic activity toward PC3, HeLa and K562 human cancer cell lines in vitro. All tested extracts exhibited moderate activity against HeLa cells (41.9-42.1 microg/mL), whereas the extract obtained with 100% ethyl acetate was the most active against K562 and PC3 cell lines (25.9 and 39.2 microg/mL, respectively). Statistical analysis revealed significant correlation between total phenolic content and cytotoxic activity against PC3 and K562 cells. HPLC identification of phenolic compounds from the extracts indicated the presence of apigenin, naringenin and kaempferol as free aglycones, and glycosides of apigenin, naringenin, quercetin and kaempferol. Among aglycones, kaempferol displayed moderate cytostatic activity against all cell lines (24.8-64.7 microM). 相似文献
95.
Gordana Pejovi? Jovan Filipovi? Ljiljana Tasi? 《Accreditation and quality assurance》2011,16(4-5):253-261
The primary role of European pharmaceutical legislation is to safeguard public health while encouraging the development of the pharmaceutical industry, creation of single market for pharmaceuticals with removed barriers to medicines trade. This article presents some important characteristics of pharmaceutical legislation in Serbia, the potential EU candidate country, and the latest improvements of existing national pharmaceutical legislation. Additional explanation is given for the Serbian negotiations with World Trade Organization and measures taken for the harmonisation with Agreements on Technical barriers to Trade (TBT), especially with Agreement on Trade-Related Intellectual Property Rights. Current status of Serbian pharmaceutical market is described, with the highlight of domestic manufacturers??capacity to comply with European Union requirements. National medicines agency is described in the framework of European medicines quality infrastructure. The role and responsibility of national medicines authority to assure access to quality, safe and efficacious medicines on Serbian market is described. The special emphasis is given to agency’s role in harmonisation process, in terms of removing unnecessary barriers to medicines trade in Serbia. 相似文献
96.
In this report, we investigated the so-called plasmonic platforms prepared to target ultra-short fluorescence and accurate instrumental response function in a time-domain spectroscopy and microscopy. The interaction of metallic nanoparticles with nearby fluorophores results in the increase of the dye fluorescence quantum yield, photostability and decrease of the lifetime parameter. The mentioned properties of platforms were applied to achieve a picosecond fluorescence lifetime (21 ps) of erythrosin B, used later as a better choice for deconvolution of fluorescence decays measured with “color” sensitive photo-detectors. The ultra-short fluorescence standard based on combination of thin layers of silver film, silver colloidal nanoparticles (about 60 nm in diameter), and top layer of erythrosin B embedded in 0.2 % poly(vinyl) alcohol. The response functions were monitored on two photo-detectors; microchannel plate photomultiplier and single photon avalanche photodiode as a Rayleigh scattering and ultra-short fluorescence. We demonstrated that use of the plasmonic base fluorescence standard as an instrumental response function results in the absence of systematic error in lifetime measurements and analysis. 相似文献
97.
98.
Gordana Stojanović Ivana Zrnzević Ivana Zlatanović Miroslava Stanković Vesna Stankov Jovanović Violeta Mitić 《Natural product research》2020,34(4):549-552
AbstractThe aim of this study was to determine, for the first time, the chemical composition of Peltigera horizontalis thallus and apothecia extracts (ether, ethyl acetate, dichloromethane and acetone) by HPLC-UV and GC-MS, and evaluate activity of genotoxic, anticholinesterase, antioxidant and antibacterial potential of acetone extracts. Major constituents of thallus extracts were gyrophoric acid, and methyl gyrophorate while dominant component of apothecia extracts was tenuiorin. The predominant volatile compounds in extracts were methyl orsellinate, dodecyl acrylate, orcinol and orcinol monomethyl ether. The thallus acetone extract at concentration of 2.0 µg mL?1 gave the greatest decrease in the micronuclei frequency (22.4%) of all tested extracts. Apothecia extract showed stronger antioxidant activity as compared to thallus extract. Tested extracts at concentration of 10?mg mL?1 exhibited inhibitory effect (16.5% for thallus and 12.8% for apothecia) on pooled human serum cholinesterase. P. horizontalis acetone extracts had no activity against the tested five bacteria strains. 相似文献
99.
Darko Anđelković Milica Branković Gordana Kocić Sanja Mitić Radmila Pavlović 《Biomedical chromatography : BMC》2020,34(1):e4720
Apple peel is frequently exposed to pesticides, especially in the last stages of the pesticide treatment practice. For a certain period, peel retains most of the applied pesticides, which precisely indicates the presence of pesticide residues. This study was conducted to establish and evaluate the method for the residue analysis of pyrimethanil, cyprodinil, trifloxystrobin, bifenthrin and boscalid by GC–MS in peel of Granny Smith, Golden Delicious and Idared varieties. The method consisted of few steps, without the routine usage of sorbents, and resulted in efficient removal of waxes, targeted as main interferences in GC–MS analysis. The matrix effect, boscalid selectivity issue, trend of lower trueness for bifenthrin in all matrices and for all analytes in Granny Smith matrix were in some way associated with the waxes. Finally, the method was applied to the analysis of three varieties of apple orchard samples, after 9 and 5 months of treatment with commercial formulations that contain pyrimethanil, cyprodinil and boscalid as active ingredients. Since the developed method consisted of few steps and used nontoxic and economic reagents, it could be implemented as a fast, economic and reliable screening method. 相似文献
100.
We describe an invariant of a contact 3-manifold with convex boundary as an element of Juhász’s sutured Floer homology. Our
invariant generalizes the contact invariant in Heegaard Floer homology in the closed case, due to Ozsváth and Szabó. 相似文献