Ion Iosub

Spectral characterisation of some materials based on natural extracts: Topic title(s): Biomaterials

The performance of some optoelectronic device materials depends on the fluorescence emission of species included. These properties could be enhanced by embedding the active molecules in DNA. Starting with the idea of special benefit offered by the interference of nano-materials and complex biomolecule DNA based properties, our work was focussed on the selection of a natural extracts containing chromophores and fluorophores compounds in order to obtained DNA based material with enhanced specific optical properties and functionalities.

Spectro-Electrochemical Properties of Pelargonidin-3-O-Glucoside

This paper presents the spectral and electrochemical properties correlated to antioxidant character attributed to anthocyans: Pelargonidin-3-O-Glucoside, Cyanidin-3-O-Glucoside, Delphinidin-3-O-Glucoside, Peonidin-3-O-Glucoside, Malvidin-3-O-Glucoside. The Anthocyans were obtained and purified from natural selective hydroalcoholic extracts using HPLC chromatography. A series of determinations through the chemical voltammetry method were performed in view of identifying the anthocyanins’ oxidation and reduction potentials. These determinations were performed in electrochemical environments with different polarities and pH, in N, N-Dimethylformamide–Ethanol-Hydrochloric acid–Water systems. The results obtained offered data regarding the stability of anthocyans in the respective media. For Pelargonidin-3-O-Glucoside we performed detailed UV-VIS spectro-electrochemical measurements, using an optically transparent thin layer electrochemical cell. The results of these determinations offered information regarding the mechanism of redox processes.

Silica Polymeric Networks Templated with D-Fructose – as Host Matrices for Natural Extracts Immobilization

In the present paper a non-surfactant templating route has been employed to prepare new fluorescence nanostructured materials, by combining some natural organic molecules present in vegetal extracts with three-dimensional silica and hybrid silica-silsesquioxane networks. The results obtained clearly indicated that organic chromophores like flavonoid compounds from two extracts with bio-active principles (orange peel extract and ornamental bush extract) can be efficiently immobilised in the host silica and hybrid matrices, using D-fructose as template. The confirmation of immobilization process was demonstrated by extensive characterization of final materials, achieved based on spectroscopy technique, fluorescence intensity measurements and transmission electron microscopy.

Biomineralization Processes in Formation of Urolits

Formation of renal calculi can be caused by various dietary disturbances, being influenced by disorders of metabolic conditions such as hypercalcemia (hypertiroidism), hyperoxaluria (dietary, enteric, primary), hypocytruria, hyperuricosuria, etc. In this article, a number of structural parameters of renal calculi with binary composition oxalates – urates have been analysed by adequate techniques: X-ray diffraction, FT-IR spectroscopy, optical microscopy and SEM/EDS. For the biggest urolits a detailed analysis on radial differentiated sections has been performed with the aim to identify the initiator role in nucleation process and to find out the mechanism and the main steps in calculi growth.

Effect of Drinking Water on Formation of Renal Calculi

The environmental impact on human health is of increasing concern mainly due to the complex interaction between various hazardous factors both on environment and within human organism. The aim of this paper is to investigate possible correlations between the quality parameters of drinking water and the formation of uroliths. The constituents of some kidney calculi sampled after surgery from 90 patients coming from the Horezu – Valcea area have been analysed, this region being identified as having the most cases of kidney lithiasis and that might be related with hard drinking waters. The study has been made during the period of 2004 – 2008. Physical – chemical methods specific for characterization of the quality of drinking waters have been used in parallel with determination of composition and structural characterization by X-ray diffraction, thermal analysis TG, ATD, FT-IR spectroscopy, optical microscopy. Four groups of uroliths have been identified: multiphase oxalate and urate, phosphate (hydroxiapatite) and carbonate, monohydrated oxalate (whewellite), and urate stones. Such research might be useful, from both chemical and biochemical point of view, for identifying the conditions that cause the inhibition of the processes related to kidney calculi formation.

Redox Properties of Some Aminoacids and Proteins

ABSTRACT In order to characterize redox properties of biomolecules, specific methods for evaluating the antioxidant capacity of some biological structures or their components (like aminoacids) are used, such as chemiluminescence (CL) and cyclic voltametry coupled with UV-VIS spectroscopy. The CL antioxidant capacity, the reduction potential (ϵ1/2), and the anodic current intensity (Ia) have been determined by controlling the behavior of the compounds under redox conditions. The value of the half-wave potential of the first peak was correlated with the reduction tendency on the electrode, and this behavior was analyzed in relation to the antioxidant capacity observed by CL.