Tellurite Glasses from the 70TeO-5XO-10PO-10ZnO-5PbF(X= Pb, Bi, Ti) System Doped Erbium Ions-The Influence of Erbium on the Structure and Physical Properties.

In this article, we present research on the influence of erbium ions on the structure and magneto-optical properties of 70TeO-5XO-10PO-10ZnO-5PbF (X = Pb, Bi, Ti) tellurite glass systems. Structural changes occurring in the glasses during doping with erbium ions were investigated using positron annihilation lifetime spectroscopy (PALS) and Raman spectroscopy. The X-ray diffraction (XRD) method was used to confirm the amorphous structure of the investigated samples.

Measurements of Defect Structures by Positron Annihilation Lifetime Spectroscopy of the Tellurite Glass 70TeO-5XO-10PO-10ZnO-5PbF (X = Mg, Bi, Ti) Doped with Ions of the Rare Earth Element Er.

The objective of the study was the structural analysis of the 70TeO-5XO-10PO-10ZnO-5PbF (X = Mg, Bi, Ti) tellurite glasses doped with ions of the rare-earth elements Er, based on the PALS (positron annihilation lifetime spectroscopy) method of measuring positron lifetimes. Values of positron lifetimes and the corresponding intensities may be connected with the sizes and number of structural defects, the sizes of which range from a few angstroms to a few dozen nanometers. Experimental positron lifetime spectrum revealed existence of two positron lifetime components τ andτ .

Voids in mixed-cation silicate glasses: Studies by positron annihilation lifetime and Fourier transform infrared spectroscopies.

PALS in comparison with FTIR studies have been applied to investigate the structure of different oxide glasses. Three components of the positron lifetime τ (τ1 para- and τ3 ortho-positronium and τ2 intermediate lifetime component) and their intensities were obtained. The results of the calculation of mean values of positron lifetimes for the investigated glasses showed the existence of a long-living component on the positron annihilation lifetime spectra.

Structural studies of polymer hydrogel and silicone hydrogel contact lenses by means of positron lifetime spectroscopy methods.

Unlabelled: PURPOSE OF JOB: Currently, there isa need to increase comfort and visual acuity man. Simultaneously improving biocompatibility and minimizing the impact of the material on the physiology of the cornea is the primary driving force behind the evolution of materials used in the manufacture of contact lenses. Despite progressive development of modern materials science, there is still the problem of reducing the level of oxygen available to the cornea resulting in pathological changes in the cornea.

Structural study of polymer hydrogel contact lenses by means of positron annihilation lifetime spectroscopy and UV-vis-NIR methods.

A study has been conducted in order to determine presence of free volume gaps in the structure of structure of polymer hydrogel contact lenses made in phosphoryl choline technology and of the degree of defect of its structure. The study was made by means of positron annihilation lifetime spectroscopy. As a result of the conducted measurements, curves were obtained, which described numbers of counts of the acts of annihilation in the time function.

Investigation of the free volume changes in one day hydrogel and one day silicone-hydrogel contact lenses by means of positron annihilation lifetime spectroscopy.

Unlabelled: PURPOSE OF JOB: The evolution of materials used to manufacture contact lenses, there is a need to increase comfort and visual acuity man while improving biocompatibility and minimizing the impact of the material on the physiology of the cornea. There is still a problem with limiting the level of oxygen available to the cornea, resulting in various diseases. Therefore, the aim of this work is to investigate the physical and structural properties of hydrogel and silicone-hydrogel contact lenses.

Investigation of free volume changes in the structure of the polymer bifocal contact lenses using positron lifetime spectroscopy PALS.

Positron annihilation lifetime spectroscopy PALS has been applied of free volume properties in bifocal contact lenses. The measurements have been made on new lenses and then after one, two, three and four weeks wear. The longest lifetime, obtained via three-component analyses of the spectra, was associated with the pick-off annihilation of ortho-positronium trapped in the free volume.

Testing of the cytotoxic effects of sulfate pulp mill waste waters.

The effect of 22 technological waste water samples and of some standards was tested on bacteria, fungi, chlorococcal algae, flagellata, plant cells, cells of Tubifex tubifex, hamster cells V79 and the fish Lebistes reticulatus. Of these 22 samples, some inhibition of cell life processes was displayed by the black liquor formed in the production of paper pulp and viscose pulp, by the waste solution produced during the preparation of bleaching agents for paper pulp and viscose pulp, and by the residual liquor after hypochlorite treatment of paper pulp.

Application of the cell growth and DNA-inhibition tests for characterizing sulfate pulp mill waste waters.

The evaluation of cytotoxic and genotoxic effects of selected technological samples from sulfate pulp mill waste waters by using the growing activity method for pseudodiploid fibroblasts V79 from lungs of the Chinese hamster and from human heteroploid fibroblasts EUE has been described along with the DNA-inhibition test for studying the synthesis of DNA after it has been influenced by the above-mentioned samples. Both the waste solution produced during the preparation of bleaching agents and the liquor generated after using hypochlorite (1st stage) as a fourth filter (after the production of paper pulp) are cytotoxic waste waters. Black liquor generated during the production of viscose pulp may have mutagenic effects and black liquor obtained from the production of paper pulp is characterized by mutagenic as well as carcinogenic effects.

Use of micronucleic test for the determination of genotoxicity of waste liquor from a magnesium bisulfite pulp mill.

Since diluted magnesium bisulfite waste liquor from a pulp mill after beech wood processing exhibited an inhibitory effect on all the model organisms used in our previous work (Cernáková et al. 1991) and the results of Ames mutagenicity test were ambiguous, micronucleic test was used for characterization. The frequency of micronuclei observed suggested that the diluted magnesium bisulfite waste liquor had a mutagenic effect under in vitro conditions of the micronucleic test.