Extraction of molybdenum from weak acid rhenium-containing solutions

The possibility of extracting molybdenum from weak acid (pH 2 to 3) rhenium-containing solutions with the non-specific extractant Aliquat 336 is studied. A mechanism for the temperature influence on extraction and in particular for the extraction of molybdenum and rhenium is proposed. It is shown that the selectivity coefficient (β = D_Mo/D_Re) depends on the concentrations of both elements and also on the NO₃^? concentration in solution. When the concentration of molybdenum and nitrate ions increases, β increases. Increasing temperature has the same effect. A modifier is essential. At low rhenium concentrations it is better to use high molecular weight alcohols (as modifier), and at high concentrations it is better to use acetophenone. The authors believe that the investigations can be generalized and that analogous results can be expected if trialkylamine (for example, trioctylamine) is used.     

Effect of the type of nutrition on the dynamics and stages of morphological changes in the liver during experimental N-nitrosodiethylamine carcinogenesis

The time course of the development of morphological changes was studied in the liver of rats given intraperitoneal injections of nitrosodiethylamine (NDEA) in a dose of 130 mg/kg, weekly, during 9 weeks, in the presence of full value hypocalorific (70% calorific value of the ration received by the control group), and hypercalorific (130% calorific value) nutrition. Four stages were distinguished in the development of the pathologic process under a chronic action of NDEA: I-alternative, II-alternative-proliferative, III--proliferative-tumorigenic, and IV--the stage of malignant growth. No matter what character of nutrition was, continuous NDEA administration induced the development of neoplasms in the liver 120 days after the commencement of the injections. The frequency of tumorigenesis rose significantly when NDEA was injected in the presence of hypo- or hypercalorific rations.     

Synthesis of novel tetracationic asymmetric monomeric monomethine cyanine dyes – highly fluorescent dsDNA probes

Quaternisation of monomethine cyanine dyes bearing haloalkyl chains, with the appropriate monoquaternised 1,4‐diazabicyclo[2.2.2]octane derivatives, yielded novel tetracationic asymmetric monomeric monomethine cyanine dyes belonging to the thiazole orange family. The optimal conditions for this reaction were investigated. The longest wavelength absorption maxima of the studied dyes are in the region 504–507 nm. The molar absorptivities of the target dyes are high, with values between 70 500 and 99 500 l mol^?1 cm^?1. The fluorescence intensity and the fluorescence quantum yields of the free dyes in solution or in the presence of double‐stranded DNA were determined using thiazole orange for comparison. The dyes are suitable for nucleic acid detection and have a high binding affinity, attributable to their four positive charges.     

Versatile gradients of chemistry, bound ligands and nanoparticles on alumina nanopore arrays

Nanoporous alumina (PA) arrays produced by self-ordering growth, using electrochemical anodization, have been extensively explored for potential applications based upon the unique thermal, mechanical and structural properties, and high surface-to-volume ratio of these materials. However, the potential applications and functionality of these materials may be further extended by molecular-level engineering of the surface of the pore rims. In this paper we present a method for the generation of chemical gradients on the surface of PA arrays based upon plasma co-polymerization of two monomers. We further extend these chemical gradients, which are also gradients of surface charge, to those of bound ligands and number density gradients of nanoparticles. The latter represent a highly exotic new class of materials, comprising aligned PA, capped by gold nanoparticles around the rim of the pores. Gradients of chemistry, ligands and nanoparticles generated by our method retain the porous structure of the substrate, which is important in applications that take advantage of the inherent properties of these materials. This method can be readily extended to other porous materials.     

Effects of Supplemental Drugs on Hexaminolevulinate (HAL)-Induced PpIX Fluorescence in Bladder Cancer Cell Suspensions

Seven different inhibitors of the heme metabolic pathway were applied in combination with HAL to study the formation of PpIX in bladder cancer HT1197 and normal fibroblast HFFF2 cells ex vivo, specifically with the aim to increase the fluorescence contrast between cancer and non-cancer cells. The mRNA expression of enzymes involved in the heme biosynthesis pathway were measured via PCR following incubation with the drugs in order to link the fluorescence levels and metabolic activity. The exogenous administration of HAL does lead to cancer-specific PpIX accumulation. However, the contrast between cancer and normal cells in suspension was not enhanced by the enzyme inhibitors and iron-chelating agents tested, nor did the mRNA expression necessarily correlate with the fluorescence intensity. The results indicate that a difference in the metabolic activity of cells in suspension may limit the applicability of exogenous enzyme inhibitor administration as a mean to improve the fluorescence-based detection of cancer cells shed in body fluids.