Optimisation of a photochemical sensor for total organic carbon measurement

A new tool for the measurement of TOC based on the heterogeneous photocatalysis activated by two different light sources has been planned. The instrument is constituted by a cell where the degradation occurs thanks to both the UV irradiation and the presence of a powered catalyst and by a measurement cell lodging CO2 gas permeable membrane electrode (detector), thermometer, inlet and outlet ways for the samples. One of the sources has a maximum emission at 254nm, while the other simulates the solar spectrum. A suspension (1 g/L) of titanium dioxide (Degussa P25) has been used to catalyse the process. A magnetic stirrer and a circulating pump avoid the deposition of the catalyst on the bottom of the reactor. The online measurement of produced CO2 was performed on 11 molecules (commercial names: Parachlorophenol, D-Glucose, Acid Blue 29, Atraton, Aspirin, Dimethoate, Aldicarb sulfone, Hydroquinone, (R)-Propranolol, Citric acid, Atrazine) to test the system efficiency. The experimental CO2 value was compared with the theoretical TOC value calculated by means of the structure's formula.     

CHANGES IN SUPEROXIDE DISMUTASE, CATALASE AND GLUCOSE-6-PHOSPHATE DEHYDROGENASE ACTIVITIES OF RABBIT ALVEOLAR MACROPHAGES: INDUCED BY POSTNATAL MATURATION AND/OR IN VITRO HYPEROXIA

Abstract— The total superoxide dismutase activity of rabbit alveolar macrophages (AM) increased twofold during the first postnatal week. This increase in superoxide dismutase activity was primarily mitochondrial and paralleled the increase in the number of mitochondria in these cells which has been previously reported. The superoxide dismutase activity of AM in culture for 18 h was significantly increased by hyperoxia; catalase activity in hyperoxic conditions was slightly adversely affected; glucose-6-phosphate dehydrogenase activity was increased but not significantly over control values. Hyperoxic cultures beyond 42 h decreased the total number of viable cells and the superoxide dismutase activity expressed per viable cell; the disappearance of catalase and glucose-6-phosphate dehydrogenase activities in this period, however, was more rapid in control alveolar macrophages than those under hyperoxia.     

A chemometric approach to the historical and geographical characterisation of different terracotta finds

The development of modern analytical instrumental techniques has allowed to solve a lot of problems concerning all kinds of disciplines, but often we can obtain for the analysed samples very numerous data, obtained by means of analytical techniques. So the effort of the analysts is more and more paid on the elaboration of a so high number of data. We can find a typical example in the classification and study of archaeological finds. In the archaeometry, that is the application of scientific methods and analysis techniques to archaeological issues, one of the most important step is the statistical elaboration of multivariate data obtained by physical and chemical analysis of ancients artefacts. This study was carried out on 20 different pottery samples coming from different periods. The 20 analysed terracotta finds come from 4 different archaeological sites, three Italian and one Libyan. For the analysis we used ICP–AES, thermogravimetric (TG) and thermomechanical (TMA) techniques; the main technique used to elaborate the data was the Principal Component Analysis (PCA). We already knew, approximately, the “burning age” of the finds and we had to check if some eigenvector of Principal Components Analysis could fit with that age. Few milligrams of finds were used for ICP–AES, TGA and TMA analysis obtaining, after a reduction, a matrix of 11 variables. The results show a good correlation between age and PC1.     

Ecopharmacology: Deliberated or casual dispersion of pharmaceutical principles, phytosanitary, personal health care and veterinary products in environment needs a multivariate analysis or expert systems for the control, the measure and the remediation

The increasing human and animal use and abuse of drugs as well as of personal health care and gross domestic products, involve disposal and waste problems and, as a consequence, affect the environmental condition. Actually most of the active principles are complex synthesised organic molecules that react, inside human or animal body, by specific biochemical reactions that in no case can reach a 100% yield and produce residues that could be more noxious of the starting compounds. Just reading the indication sheet accompanying any drugs, it is easy to state that no drug can be considered healthy, so, their use constitutes a serious pollution source. The full awareness of this relatively new environmental problem let many researchers to face it from different point of view. Current studies are considering the sources of these substances in the environment, the effects on human health as well as on the flora and fauna species, the recalcitrance and possible degradation methods, analytical techniques able to determine them and their metabolites even at low concentrations and in complex matrices.Literature on the subject continuously increases and a comparison of all data became more and more difficult both for a single drug and for different ones based on the same or different active principles. This is a typical case in which chemometrics can extract a full information in the easier way, so the design of a European database coupled to suitable expert system software should be strongly suggested.