Variability of total flavonoid and mucilage content of wild growing chamomile (Matricaria recutita L.) populations

During our investigation 50 wild growing chamomile populations’ active substance content, among them total flavonoid content and swelling index referring to mucilage content were examined in 2009 in the main chamomile collection areas of Hungary. Swelling index was determined according to the general and specified descriptions of Althaeae folium monograph of European Pharmacopoeia, while total flavonoid content was measured by the method described in the monograph of Crataegi folium cum flore. The 50 Hungarian wild growing chamomile populations proved to be very heterogeneous in terms of the examined features. The swelling index of their flower drug samples changed between 15.8 and 80.8 and their total flavonoid content varied from 0.94 to 2.28 %.Significant correlation was also found between meteorological conditions and evaluated characteristics: there was medium strong positive correlation between spring total heat unit (sum of daily 10 °C higher average temperatures of the period lasted from 1st of March, 2009 until the day before flower collection) as well as total heat unit of 10 days before harvest and swelling index (r = 0.50-0.56), furthermore medium strong negative connection could be seen between total heat units and total flavonoid content (r = -0.60-0.65). Based on these findings it can be ascertained that raising temperature affects the mucilage accumulation positively, however, it has a negative effect on the amount of flavonoids

Transfer of Graphene with Protective Oxide Layers

Transfer of graphene, grown by Chemical Vapor Deposition (CVD), to a substrate of choice, typically involves deposition of a polymeric layer (typically, poly(methyl methacrylate, PMMA or polydimethylsiloxane, PDMS). These polymers are quite hard to remove without leaving some residues behind. Here we study a transfer of graphene with a protective thin oxide layer. The thin oxide layer is grown by Atomic Deposition Layer (ALD) on the graphene right after the growth stage on Cu foils. One can further aid the oxide-graphene transfer by depositing a very thin polymer layer on top of the composite (much thinner than the usual thickness) following by a more aggressive polymeric removal methods, thus leaving the graphene intact. We report on the nucleation growth process of alumina and hafnia films on the graphene, their resulting strain and on their optical transmission. We suggest that hafnia is a better oxide to coat the graphene than alumina in terms of uniformity and defects.Comment: 13 pgs, 13 figure

Nanooptomechanical Transduction in a Single Crystal with 100% Photoconversion.

Materials that exhibit nanooptomechanical transduction in their single-crystal form have prospective use in light-driven molecular machinery, nanotechnology, and quantum computing. Linkage photoisomerization is typically the source of such transduction in coordination complexes, although the isomers tend to undergo only partial photoconversion. We present a nanooptomechanical transducer, trans-[Ru(SO2)(NH3)4(3-bromopyridine)]tosylate2, whose S-bound η1-SO2 isomer fully converts into an O-bound η1-OSO photoisomer that is metastable while kept at 100 K. Its 100% photoconversion is confirmed structurally via photocrystallography, while single-crystal optical absorption and Raman spectroscopies reveal its metal-to-ligand charge-transfer and temperature-dependent characteristics. This perfect optical switching affords the material good prospects for nanooptomechanical transduction with single-photon control