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Biomedical subjects

V Valković

Publications and source records attributed to V Valković.

12 recordsLinked to original sources
PubMed2006

The detection of landmines by neutron backscattering: exploring the limits of the technique.

Neutron backscattering (NB) sensors have been proposed for Humanitarian De-mining applications. Recently, a prototype hand-held system integrating a NB sensor in a metal detector has been developed within the EU-funded DIAMINE Project. The results obtained in terms of performance of the NB systems and limitations in its use are presented in this work. It is found that the performance of NB sensors is strongly limited by the presence of the soil moisture and by its small-scale variations. The use of the neutron hit distribution to reduce false alarms is explored.

Computer Simulation↗
PubMed1989

Analysis of metal diffusion from crown to the human teeth.

Proton induced X-ray emission spectroscopy (PIXE) has been used to determine the intensity of metals from crowns in human teeth. In order to measure elements distribution across the tooth section, proton beam (3 MeV) has been collimeted to provide a spatial resolution of 300 microns. The samples were selected according to the time of insertion of crowns and the kind of alloys they were made of. The results show the intensities of gold, zinc and copper in abutment teeth. It was not found any intensity of paladium and amount of silver was not significant.

Crowns↗
PubMed1985

Incorporation routes of elements into human hair; implications for hair analysis used for monitoring.

A study has been made on the incorporation of some trace elements and minerals into human hair by measuring their distributions across hair diameters. For this study the Particle Induced X-ray Emission (PIXE) technique using the proton microbeam of the Vrije Universiteit of Amsterdam has been applied. Results of measurements on single hair strands at different positions in the root and outside the skin provide evidence that the elements not only can enter the cortex via the matrix but also via the hair root sheaths. Moreover, there are indications that the distribution of an endogenous element is not always homogeneously spread over a cross section of the hair. Endogenous Fe and Pb seem to be peaked on the periphery of the hair by natural means, while the elements S,Zn and Cu of the samples measured are found to be distributed homogeneously across the hair diameter. The consequences for hair analysis in use for monitoring the trace elements status of an individual are discussed.

Adult↗
PubMed1980

Is aluminum an essential element for life?

Aluminum is proposed to be an essential element for life based on the idea that the chemical composition of living organisms must reflect to some extent the composition of the environment in which they evolved.

Aluminum↗
PubMed1976

Trace-element concentrations in human hair measured by proton-induced x-ray emission.

Proton-induced x-ray spectroscopy has been used to measure trace elements concentration ratios for 10 elements relative to Zn on a group of the population in the harbor city of Rijeka, Yugoslavia. The average biologic levels of elemental ratios for the inhabitants of this region have been established. The presence of pollutants has been confirmed by studying the variation of elemental concentration ratios along single samples of hair.

Arsenic↗
PubMedDate not supplied

Analysis of trace elements in the human labyrinth by using proton microprobe.

The concentration of zinc in the spiral tract is age-dependent. The accumulation of zinc starts at the bone surface towards the fundus of the internal auditory meatus and continues throughout the whole thickness of the separating wall to reach in advanced age the bone surface towards the basal coil of the cochlea. The concentration of calcium decreases with age. These findings prove our previous histological and densitometric as well as macroscopical investigations of this region.

Adolescent↗