Monocationic Chlorin as a Promising Photosensitizer for Antitumor and Antimicrobial Photodynamic Therapy

Cancer is one of the leading causes of death worldwide. Despite substantial progress in the understanding of tumor biology, and the appearance of new generations of targeted drugs and treatment techniques, the success achieved in this battle, with some notable exceptions, is still only moderate. Photodynamic therapy (PDT) is a successful but still underestimated therapeutic modality for treating many superficial cancers. In this paper, we focus on the extensive investigation of the monocationic chlorin photosensitizer (PS), considered here as a new photosensitizing agent for both antitumor and antimicrobial PDT. This monocationic chlorin PS (McChl) obtained from methylpheophorbide a (MPh) via a two-step procedure is well soluble in water in the physiological temperature range and forms stable complexes with passive carriers. McChl generates singlet oxygen with a good quantum yield in a lipid-like environment and binds mainly to low- and high-density lipoproteins in a vascular system. A comparison of the photodynamic activity of this agent with the activity of the well-established photosensitizer chlorin e6 (Chl e6) clearly indicates that McChl provides a much more efficient photoinactivation of malignant and microbial cells. The pilot PDT treatment of M1 sarcoma-bearing rats with this PS demonstrates its good potential for further preclinical investigations

Ethanol to Acetaldehyde Conversion under Thermal and Microwave Heating of ZnO-CuO-SiO2 Modified with WC Nanoparticles

The nonoxidative conversion of ethanol to acetaldehyde under thermal and microwave heating was studied on mixed oxide ZnO-CuO-SiO2 catalysts modified with additives of tungsten carbide nanoparticles. The results revealed that the WC-modified catalyst exhibited superior activity and selectivity under microwave heating conditions. It is assumed that when microwave heating is used, hot zones can appear at the contact points of WC nanoparticles and active centers of the mixed oxide ZnO-CuO-SiO2 catalyst, which intensively absorb microwave energy, allowing the more efficient formation of acetaldehyde at moderate temperatures. Thermodynamic calculations of equilibrium concentrations of reagents and products allowed us to identify the optimal conditions for effective acetaldehyde production. The initial catalyst and the catalyst prepared by the coprecipitation of the oxides with the addition of WC were characterized by physicochemical methods (TPR-H2, XRD, DRIFTS of adsorbed CO). The active centers of the oxide catalyst can be Cu+ cations

Amino Acid Solvation in Aqueous Kosmotrope Solutions: Temperature Dependence of the L-Histidine-Glycerol Interaction

We have studied thermodynamics of interaction between the aromatic amino acid l-histidine and glycerol, which is one of the most important stabilizing agents for proteins in water. The pair and triplet interaction parameters have been extracted from enthalpy and solubility data using standard thermodynamic manipulations in a wide temperature range. Our results indicate for the first time that the l-histidine–glycerol pair and triplet interactions are characterized by rather small enthalpy and entropy changes, which do not depend on temperature in either cold or hot water. These temperature-independent enthalpies and entropies of interaction lead to zero heat capacity changes during the amino acid transfer from water to both dilute and rather concentrated aqueous glycerol solutions. We attribute this behavior to a delicate balance between contributions from hydrophobic and hydrophilic fragments in the solute molecules. This unique feature appears to be the major reason that thermodynamics of pair and triplet interactions are nearly identical at standard and physiological temperatures

Pd/H-Beta catalysts: Characterization and reactivity in piperonyl alcohol selective oxidation

Pd/H-Beta catalysts with different silica-to-alumina ratio prepared by an impregnation method have been studied by XANES/EXAFS, IR, XRD and TEM. It was shown that palladium in calcined Pd/H-Beta samples exists as palladium oxide that can be easily reduced to Pd metal. The catalysts were tested in selective oxidation of piperonyl alcohol to piperonylaldehyde at 80 °C. The Pd/H-Beta zeolite catalysts with the lowest silica-to-alumina ratio possess the highest catalytic activity in benzylic alcohol oxidation reaction