Near-infrared persistent luminescent materials have great potential for in vivo bioimaging and night-vision surveillance due to their long-lasting autofluorescence-free emission through deep tissues multicycle photostimulated luminescence by releasing energy from captured traps using high-intensity 808 or 980 nm lasers. However, phosphors combining both near-infrared are found mostly chromium d...

Catechins and theaflavins, polyphenolic compounds derived from tea (Camellia sinensis, fam. Theaceae), have been reported to have a wide range of biological activities including prevention of tooth decay and oral cancer. The present study was undertaken to determine the usefulness of green tea leaves and black tea extract for the delivery of catechins and theaflavins to the oral cavity. After h...

We discuss oxygen and cation diffusion processes in oxygen ion conductors. While the high oxygen diffusivity determines the proper oxygen ion conductivity, slow cation diffusion processes are important for sintering and degradation processes. In the first part of the paper we discuss an analytical model for the ionic conductivity of a strongly acceptor doped, fluorite-type oxygen ion conductor,...

a spectrophotometric method is used to determine the acidity constants of some derivatives of 9,10-anthraquinone in binary methanol-water mixtures at 25 °c. there is a linear inverse relationship between pka of all acids and the mole fraction of methanol in the mixed solvent. the influence of substituents in the molecular structure on the ionization constants is discussed.

quercetin, a ubiquitous flavonol, represents a promising leading drug for development of new chemotherapeutic agents. however, its limited cytotoxicity to cancer cells hampers its clinical use. in order to obtain novel quercetin derivatives with superior cytotoxicity, seven alkylated quercetin derivatives were synthesized. solubility of these derivatives was determined by turbidimetry. cytotoxi...

a series of new hexahydroquinoline and 1,4-dihydropyrimidine derivatives were synthesized. condensation of 2-methyl- thiazole-4-carboxaldehyde (1) with 1,3-cyclohexanedione and alkyl 3- aminocrotonate afforded 4-(2-methyl-thiazol-4-yl)-hexahydroquinoline while condensation of aldehyde (1) with benzoyl acetone and thiourea gave 1,4-dihydropyrimidine derivatives. the stereochemistry of 1,4-dihydr...

Peanut skin extract (PSE) and grape seed extract (GSE) are derived from waste products in the wine and peanut industries, respectively. Both have high concentrations of polyphenols, known to possess antioxidant and antimicrobial properties. PSE primarily contains "A-type" procyanidins, while GSE primarily contains "B-type" procyanidins. These differ structurally, but are both isomers of epicate...

The structural chemistry of proanthocyanidin molecules has been investigated in temperate zone plants, but few studies have been done with plants of the Amazonian lowland tropical wet forests where herbivore pressure is more extensive and diverse. Using MALDI-TOF mass spectrometry, we report unique properties of the proanthocyanidin structural chemistry in two neotropical Cecropia species, C. p...