Synthesis of advanced fluorescent probes — water-soluble symmetrical tricarbocyanines with phosphonate groups

Russian Chemical Bulletin - A method for the synthesis of a series of water-soluble heptamethine indocyanine dyes containing a phosphonate group in the substituent bonded to the quaternary nitrogen...     

Approximation of Fractional Brownian Motion by Martingales

We study the problem of optimal approximation of a fractional Brownian motion by martingales. We prove that there exists a unique martingale closest to fractional Brownian motion in a specific sense. It shown that this martingale has a specific form. Numerical results concerning the approximation problem are given.     

2-(benzimidazol-2-yl)-3-hydroxychromone derivatives: spectroscopic properties and a possibile alternative intramolecular proton phototransfer

Three 2-(benzimidazol-2-yl)-3-hydroxychromone derivatives were synthesized. Their spectroscopic and fluorescent properties, due to excited state intramolecular proton transfer (ESIPT) from OH to carbonyl, were studied. Theoretical possibility of an alternative intramolecular H-bonding and experimental evidence for such behavior are discussed.      

The Anti-Inflammatory Effect of a γ-Lactone Isolated from Ostrich Oil of Struthio camelus (Ratite) and Its Formulated Nano-Emulsion in Formalin-Induced Paw Edema

The ostrich oil of Struthio camelus (Ratite) found uses in folk medicine as an anti-inflammatory in eczema and contact dermatitis. The anti-inflammatory effect of a γ-lactone (5-hexyl-3H-furan-2-one) isolated from ostrich oil and its formulated nano-emulsion in formalin-induced paw edema was investigated in this study. Ostrich oil was saponified using a standard procedure; the aqueous residue was fractionated, purified, and characterized as γ-lactone (5-hexyl-3H-furan-2-one) through the interpretation of IR, NMR, and MS analyses. The γ-lactone was formulated as nano-emulsion using methylcellulose (MC) for oral solubilized form. The γ-lactone methylcellulose nanoparticles (γ-lactone-MC-NPs) were characterized for their size, shape, and encapsulation efficiency with a uniform size of 300 nm and 59.9% drug content. The γ-lactone was applied topically, while the formulated nanoparticles (NPs) were administered orally to rats. A non-steroidal anti-inflammatory drug (diclofenac gel) was used as a reference drug for topical use and ibuprofen suspension for oral administration. Edema was measured using the plethysmograph method. Both γ-lactone and γ-lactone-MC-NPs showed reduction of formalin-induced paw edema in rats and proved to be better than the reference drugs; diclofenac gel and ibuprofen emulsion. Histological examination of the skin tissue revealed increased skin thickness with subepidermal edema and mixed inflammatory cellular infiltration, which were significantly reduced by the γ-lactone compared to the positive control (p-value = 0.00013). Diuretic and toxicity studies of oral γ-lactone-MC-NPs were performed. No diuretic activity was observed. However, lethargy, drowsiness, and refusal to feeding observed may limit its oral administration.     

Structure and Luminescent Properties of the 4-Arylidene-2-Aryl-5-Oxazolones(Azlactones)In Solution and Crystalline State

Experimental and theoretical evaluations have proven that very low fluorescence quantum yields of azlactones in solution are not caused by an efficient inter system crossing from S₁*(ππ) to T*(nπ) states, but rather from solvation and steric effects, that result in non-planarity of the molecular system. High fluorescence quantum yields in the solid state are attributed to the planarity of the azlactone molecule upon packing into the crystal lattice. Supporting evidence was found upon observation of the excited state proton transfer (ESIPT) bands of fluorescence emissions of o-hydroxyarylidene derivatives. The photoinstability of azlactones in liquid states are attributed to photochemical E-Z isomerization and cleavage of the hetero ring α to the carbonyl group.     

1,4-bis-(3-hydroxy-4-oxo-4H-chromen-2-yl)-benzene (bis-flavonol): synthesis, spectral properties and principle possibility of the excited state double proton transfer reaction

Synthesis and systematic investigation of the spectral-luminescent properties of “bis-flavonol” {1,4-bis-(3-hydroxy-4-oxo-4H-chromen-2-yl)-benzene} were performed. Hypothetical possibility for the double excited-state proton transfer reaction in bis-flavonol is discussed based on both quantum-chemical modeling and experimental data. Consecutive S₁*-state transfer of the two protons of the title molecule is shown to be energetically unfavorable, however, still preserving a possibility for the concerted double proton transfer in the excited dienol form.     

Free subsemigroups in topological semigroups

We prove that a complete metrizable topological semigroup with identity that contains a free dense subsemigroup and no commutative neighbourhoods of identity is almost free. We apply this result to the full transformation semigroup of countable degree and the semigroup of automaton transformations over finite alphabet.