Characterization of nanoparticles combining polyamine detection with photodynamic therapy

Polyamine detection and depletion have been extensively investigated for cancer prevention and treatment. However, the therapeutic efficacy is far from satisfactory, mainly due to a polyamine compensation mechanism from the systemic circulation in the tumor environment. Herein, we explore a new solution for improving polyamine detection as well as a possible consumption therapy based on a new photosensitizer that can efficiently consume polyamines via an irreversible chemical reaction. The new photosensitizer is pyrrolopyrroleaza-BODIPY pyridinium salt (PPAB-PyS) nanoparticles that can react with the over-expressed polyamine in cancer cells and produce two photosensitizers with enhanced phototoxicity on cancer destruction. Meanwhile, PPAB-PyS nanoparticles provide a simultaneous ratiometric fluorescence imaging of intracellular polyamine. This combination polyamine consumption with a chemical reaction provides a new modality to enable polyamine detection along with photodynamic therapy as well as a putative depletion of polyamines for cancer treatment and prevention.

Gas-liquid mass transfer with instantaneous chemical reaction in a slurry bubble column containing fine reactant particles

In this study, the mass transfer accompanied by an instantaneous irreversible chemical reaction in a slurry bubble column containing sparingly soluble fine reactant particles has been analyzed theoretically. Based on the penetration theory, combining the cell model, a one-dimensional mass transfer model was developed. In the model, the effects of the particle size and the particle dissolution near the gas-liquid interface on the mass transfer were taken into account. The mass transfer model was solved and an analytical expression of the time-mean mass transfer coefficient was attained. The reactive absorption of SO2from gas mixtures into Mg(OH)2/water slurry was investigated experimentally in a bubble column reactor to validate the mass transfer model. The results indicate that the present model has good predicting performance and could be used to predict mass transfer coefficient for the complicated gas-liquid-solid three-phase system with an instantaneous irreversible chemical reaction.

Mathematical Modelling of Methane-Air Combustion in a Channel with a Porous Axial Insert

In the paper we construct a mathematical model of turbulent flow, combustion and heat transfer in an axisymmetric chamber with an axial zone of a compacted particulate material. The averaged equations written using the model of interacting and interpenetrating continua contain diffusion equations of individual components, the energy equation for the gas and the porous structure, the motion equation for a mixture of gaseous components, as well as the equation of the turbulence model. This system is closed by the equations of continuity and condition of the mixture. In the flow, an irreversible chemical reaction of stoichiometric mixture of methane and oxygen proceeds. Numerical study of porosity influencing the nature of turbulent combustion is conducted.

Theoretical Study of the Oxidation Mechanism of Hematoxylin in Aqueous Solution

The oxidation of the two catechol rings A and B in the chemical structure of hematoxylin in aqueous solution has been studied theoretically in order to identify the mechanism of oxidation. In a recent experimental study, the oxidation mechanism of hematoxylin was designated an ErCiEr process in which an irreversible chemical reaction (Ci) followed the reversible chemical electrochemical oxidation (Er) of the catechol unit connected to the six-membered ring of the molecule (ring A). The theoretical results presented herein indicate that the electrochemical oxidation of ring B is actually slightly more favoured than ring A, although the potential separation is so small that they were unable to be distinguished in the experimental study. We therefore suggest that the most likely mechanism is ErErCiEr, in which two reversible electrochemical oxidation reactions (Er) occur preceding the irreversible chemical reaction (Ci), though we cannot rule out a contribution from ErCiEr. The calculated oxidation potential (0.719 V v. standard hydrogen electrode) is in close accord with the experimental value (0.759 V v. standard hydrogen electrode). The deprotonation of five hydroxyl groups of hematoxylin in aqueous solution is also studied and the order of acidic strength of these groups has been identified.

The Quenching Characteristics of Gas Deflagration Flame in Narrow Channel

In order to obtain fire retardant mechanism of gas deflagration flame in narrow channel, a numerical simulation adopting PISO algorithm and self-adapted grids was presented based on the single-step irreversible chemical reaction and the combustion model of EBU-Arrhenius. The numerical dates are well compatible with experimental results and indicate that the initial flame velocity and gap of channel are directly responsible for the quenching distance. And the smaller the flame velocity or gap of channel, the shorter the quenching distance, which means simpler to quench gas deflagration flame.