Speciation of Se,Fe and Zn in Human Milk Whey: The use of Instrumental Neutron Activation Analysis (INAA) to corroborate element profiles measured with Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES)

In human milk trace elements normally exist in a form which can easily be absorbed by the newborn infant. For investigations of the bioavailability of trace elements it is necessary to carry out a speciation analysis of the elements of interest. An independent analytical method has been used for the quality control of the shape of the element profiles obtained from the speciation analysis of Se, Fe and Zn in individual samples of human milk whey after chromatographic separation. For the element detection in the untreated milk fractions Instrumental Neutron Activation Analysis (INAA) was chosen as the reference method. Element distribution patterns have been obtained with Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES) using on-line digestion of the fraction, reduction and hydride formation of Se ("T"-mode). Prior results are compared with those obtained by means of element detection in the untreated fractions ("U"-mode) with ICP-AES. The elution profiles of Se, Fe and Zn in human milk whey obtained by means of ICP-AES detection using the "T"-mode show good agreement with the distribution patterns obtained with INAA. Recoveries of 103% for Fe, 86% for Zn and 87% for Se were obtained. The element distribution patterns of Fe and Zn obtained with ICP-AES speciation using the "T"-mode also show good agreement with those obtained by means of ICP-AES using the "U"-mode.     

Investigations of silicone breast implants with the NMR-MOUSE

Silicone breast implants are used for breast augmentation and breast reconstruction. The issues of concern associated with such implants are: (a) the quality control of each implant before implantation, and (b) the detection of implant bleeding after implantation. We have studied the use of the Nuclear Magnetic Resonance-MObile Universal Surface Explorer (NMR-MOUSE) for the nondestructive testing of (a) the quality of implant shells, and (b) changes in implant gel due to leakage of body fluid into the implant. Depth profiles measured nondestructively through implant shells at different positions of each implant by the Profile NMR-MOUSE assured good reproducibility of the quality and thickness of different shell layers. The leakage of implants upon rupture was mimicked by observing changes in the transverse NMR relaxation time of the implant gel upon ingress of physiological saline solution and safflower oil through the rupture. Results demonstrate that nondestructive testing with unilateral NMR is a potential method for use in the quality control of implants and for the screening of implants for rupture after implantation.     

Identification of the New Metabolite of Nebivolol Using Liquid Chromatography Coupled with High-Resolution Mass Spectrometry and Chemometrics

In this study, the phase I hepatic metabolism pathway of a cardiovascular drug nebivolol was proposed on the basis of a human liver microsomes assay with the use of LC-HR-MS coupled with the chemometric method. Six biotransformation products were found with the assistance of chemometric analysis. Five of them were identified as the previously reported products of alicyclic hydroxylation and dihydroxylation, aromatic hydroxylation, as well as alicyclic oxidation of the parent compound. Moreover, one metabolite, not reported so far, was found to be a product of N-dealkylation of nebivolol—2-amino-1-(6-fluoro-3,4-dihydro-2H-1-benzopyran-2-yl)ethan-1-ol. The novel metabolite was submitted to an in silico toxicity analysis to assess its biological properties. The applied computational methods indicated a significantly elevated risk of its mutagenic activity, compared to the parent molecule. Several metabolites of the nebivolol described in the literature were not detected in this study, indicating their non-hepatic origin.     

Larmor precession in polarization spectroscopy with spatially separated beams

Sodium vapour in a sealed cell is irradiated by two counter-propagating but laterally displaced beams from the same laser, tuned to one of the hf components of the D₁ line. Atoms pumped by the stronger beam, circularly polarized, precess in a transverse magnetic field, < 300 mG, during their passage to the weaker beam where their orientation is monitored. The observed signals are interpreted quantitatively.     

Iodine concentration in different human brain parts

Iodine is one of the most important essential elements as demonstrated by the fact that its deficiency can cause goitre. Nevertheless, quantitative data on its concentration in biological materials, especially in the human brain, are scarce. There is therefore a demand for accurate and reliable information on iodine in these types of samples. The purpose of the present work was to determine the concentration of total iodine in some control human brain parts by rapid radiochemical neutron activation analysis. Our second goal was to determine I distribution between lipid fraction and in brain tissue without lipid by applying two types of solvent extraction methods. The results were checked by the analysis of biological standard reference materials with certified or literature values for iodine and good agreement was found.     

Possibilities of using hafnium neutron filters for reactor NAA with fast neutrons

The possibilities of using hafnium irradiation filters for reactor fast neutron activation analysis have been evaluated. The filter characteristics of hafnium for this application are discussed and compared with some traditional filter materials. The main advantage for hafnium is its ability to remove a great portion of the slowing down neutrons, which may enhance the sensitivity of determination via threshold reactions.     

Concept of epitaxial silicon structures for edge illuminated solar cells

A new concept of edge illuminated solar cells (EISC) based on silicon epitaxial technique has been proposed. In this kind of photovoltaic (PV) devices, sun-light illuminates directly a p-n junction through the edge of the structure which is perpendicular to junction surface. The main motivation of the presented work is preparation of a working model of an edge-illuminated silicon epitaxial solar cell sufficient to cooperation with a luminescent solar concentrator (LSC) consisted of a polymer foil doped with a luminescent material. The technological processes affecting the cell I–V characteristic and PV parameters are considered.