A comparison of protoporphyrin IX and protoporphyrin IX dimethyl ester as a photosensitizer in poorly differentiated human nasopharyngeal carcinoma cells

Protoporphyrin IX dimethyl ester (PME), a dimethyl esterification of protoporphyrin IX (PpIX), exhibits higher intracellular uptake into NPC/CNE2 cells, a poorly differentiated human nasopharyngeal carcinoma, than does PpIX. Phototoxicity studies reveal PME to be a more potent photosensitizer than is PpIX, at the early and late incubation time points. Correlating phototoxicity with subcellular localization indicates that PME is a more potent photosensitizer when its primary target of photodamage is mitochondria. Also, additional targeting of lysosome enhances phototoxicity.     

Sorption of Certain Metal Ammine Complexes on Hydrous β-SnO2

Sorption of ammine complexes of Ni⁺², Cu⁺², Zn⁺² and Cd⁺² on hydrous Tin dioxide has been studied at different pH values. It has been found that qΔ and Kd values attain a maximum with increasing pH, beyond which a fall is observed. The selectivity quotients of the exchanger material towards competing pairs (Cu⁺²-Zn⁺², Cu⁺²-Cd⁺², Cu⁺²-Ni⁺²) of complex ions have been measured as a function of the concentration of the external solution. The selectivity of the exchanger material towards the preferred ion decreased with increase in the concentration of the competing ions in the external solution. The selectivity and the sorption values (qδ) follow the same order.     

Polynomial expansion of log relative viscosity and its application to polymer solutions

Solomon and Ciuta's equation has been deduced from first principles and has been shown to be merely an algebraic consequence of the definition of intrinsic viscosity. Secondly, a consequence of this equation that [η]c should be linear with \documentclass{article}\pagestyle{empty}\begin{document}$\sqrt {2\eta {\rm sp} - 2\ln \eta {\rm rel}}$\end{document} with unit slope, is found to be fairly accurate when examined against literature and our own data, and so this equation is commended not only for single-point determination of [η] but also for representing viscosity variation with concentration up to η_sp < 0.60. Thirdly, higher-order approximations are found to be less suitable. Other consequences of Solomon and Ciuta's equation are discussed.     

Shape of the clusters of a percolative system in the presence of tunneling bonds and a finite electric field

We consider a model correlated percolative system on a 2D square lattice with a finite electric field applied accross its two opposite sides. We study the shape of the clusters formed with the addition of a new kind of bond (we call them tunneling bonds) which respond only above a finite threshold voltage. As expected, the clusters do have an overall elongated shape in the-direction of the applied field. Intuitively, one expects the elongation (with the aspect ratio >1) to increased indefinitely with the field. But, in a previous study, we found the model to belong to the same universality clas in the limits of a zero and an infinite electric field. We explain this behavior by studying the change in these elongated shapes as a function of the applied voltage in finite size samples and find that actually the amount of elongation takes on a maximum value at a size (L)-dependent finite voltageV _m (L) and that asV thje overall deviation from isotropy in the field direction tends to zero (i.e., aspect ratio1) again.     

Infrared free-electron laser measurement of power limiting by two-photon absorption in InSb

We have performed the first experiment on the free-electron laser (CLIO) at the Laboratoire pour l'Utilisation du Rayonnement Électromagnétique (LURE). In a transmission experiment we observed strong power limiting at wavelengths longer than the absorption edge associated with induced free carrier absorption produced by direct interband two-photon transitions in InSb. We have estimated the two-photon absorption (TPA) coefficient () of InSb at 8.9 m to be 2 cm MW^-1, by fitting the power-limiting effect with a simple theoretical model. An important feature of this result is that we are utilizing the broad tunability of the FEL to explore the TPA theory to shorter wavelengths than hitherto available with CO₂ lasers. The result is in broad agreement with the longer-wavelength measurements of Sheik-Bahae et al.     

Schwefel in metallurgisehen Produkten

Analytical and Bioanalytical Chemistry -