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Second Harmonic Scattering from Silver Nanocubes
Russier-Antoine, Isabelle,Lee, Hye Jin,Wark, Alastair W.,Butet, Jé,ré,my,Benichou, Emmanuel,Jonin, Christian,Martin, Olivier J. F.,Brevet, Pierre-Franç,ois American Chemical Society 2018 The Journal of Physical Chemistry Part C Vol.122 No.30
<P>The second harmonic light scattered from silver nanocubes dispersed in an aqueous suspension is investigated. The first hyperpolarizability is determined and corrected for resonance enhancement. It is shown to be similar to that of silver nanospheres with a comparable volume. The polarization-resolved analysis of the scattered harmonic intensity exhibits a surface response strongly modulated by the different multipolar field contributions. As a result, the shape does not play a leading role anymore for nanoparticles with a centrosymmetric shape when retardation must be considered. Comparing the right angle and forward-scattered polarized intensity responses, the unequal balance of the eight nanocube corners’ contribution to the total response is revealed despite the high degree of centrosymmetry of the cubic shape. It is then demonstrated with a simple model that the nanocubes’ first hyperpolarizability exhibits an octupolar tensorial symmetry. The surface integral equation method calculations are finally provided to investigate further the role of the corners’ and edges’ rounding.</P> [FIG OMISSION]</BR>
Antioxidant C-glycosylflavones of Drymaria cordata (Linn.) Willd
Raymond N. Nono,Laurence K. Nzowa,Beaudelaire K. Ponou,Re´my B. Teponno,Te´lesphore B. Nguelefack,Luciano Barboni,Le´on A. Tapondjou,박희준 대한약학회 2016 Archives of Pharmacal Research Vol.39 No.1
A new C-glycosylflavone, drymaritin E (6-C- (3-keto-b-digitoxopyranosyl)-40-O-(b-D-glucopyranosyl)- 7-methoxyl-5,40-dihydroxylflavone) 1 was isolated from the oily upper phase (SU) of the MeOH extract from aerial parts of Drymaria cordata together with two known compounds (cassiaoccidentalin A 2 and anemonin 3) and an inseparable mixture of two known C-glycosylflavones 5,40- dihydroxy-7-methoxyflavone-6-C-(200-O-a-L-rhamnopyranosyl)- b-D-glucopyranoside 4a and 5,7,30,40-tetrahydroxyflavone- 6-C-(200-O-a-L-rhamnopyranosyl)-b-D-glucopyranoside 4b. The alkaline hydrolysis of 3 led to a new hemisynthetic derivative, sodium anemonate (sodium 2-((1’E) 20-sodium-carboxylate-vinyl)-5-oxo-cyclohex- 1-ene carboxylate) 3a. The chemical structures were determined by spectroscopic methods (1H NMR, 13C NMR, 1H-1H COSY, HMBC, HSQC, and NOESY) and mass spectrometry (ESI–MS). C-glycosylflavones had significant free radical-scavenging activities on the radical 2,2-diphenyl-1-picrylhydrazyl (DPPH). However, SU and compounds 3 and 3a exhibited no activity. In particular, compound 1 exhibited a concentration-dependent radical scavenging activity on DPPH with EC50 of 31.43 lg/mL.