The introductory part of this thesis is focused on the theoretical analysis of solved problems as examining the toxicity of naphthoquinones plumbagine and juglone, especially with regard to their allelopatic action. The next section is focuses on the plant stress, caused by the action of stress factors leading to their death. There is an experimental protocol and the possibilities of determination the effect of naphthoquinones on the plant model. Experimental section discusses changing growth parameters of the plant samples in different concentrations of the naphthoquinone. There is examined cell viability and changes in the synthesis of the secondary metabolites. Data obtained by using spectrophotometric and microscopic analysis are evaluated with STATISTICA software and statistical significance are plotted.

SECO Tools manufactures tool inserts for all types of metal cutting machining. (Ti,W)C is a common raw material used in the production. At arrival, the material (Ti,W)C is always analyzed. Titanium has previously been analysed with x-ray fluorescence spectrometry, but as the calibration has previously been performed with two different types of titanium (rutile and metallic titanium), the results has differed. Because of that, this thesis project has been devoted to analyze titanium, to find the best titanium compound for producing standards. The work has been performed using literature studies and many experiments in the laboratories at SECO Tools inFagersta,Sweden. This project has included about ten working weeks. In this report the analysis methods of x-ray fluorescence spectrometry and spectrophotometry is described, as the methods has been used in the experiments. A big problem that was discovered during this project was the big standard deviation of results for the method used for analysing titanium with x-ray fluorescence. Because of that, much time of this project has been devoted to experiments trying to reduce the standard deviation between the samples, as this is vital to performing a reliable calibration. A variety of experiments has been performed without reducing the standard deviation between the samples to below 0.2 % -units for the (Ti, W) C-samples.

Magister Chirurgiae Dentium (MChD) / A total of 25 third molar teeth (erupted [9], as well as unerupted [16]), from subjects who had lived continuously since birth in an area where the water fluoride concentration was more than 1,8 ppm, were studied. (The range was 1,8 ppm - 2,64 ppm of F-). The subjects had no systemic fluoride supplementation. Tooth brushing with a fluoride containing dentifrice and, perhaps, occasional fluoride mouth rinsing was the only additional exposure to fluoride. The acid-etch biopsy technique was used to determine the fluoride and calcium concentrations at various depths on the enamel surface. The fluoride concentration of the buffered etch solution was determined with an adapted fluoride ion-selective electrode technique, and the amount of calcium by flame atomic absorption spectrophotometry. Six consecutive etchings were done on the mesio-buccal and mesio-lingual cusps of each tooth; the teeth were then washed in an alkali and the same procedure repeated on the disto-buccal and disto-lingual cusps. The depth of etch of each biopsy was calculated assuming that human enamel contains 37% Ca and has a density of 2,95g/ml. It was previously reported, (Grobler & Joubert, 1988), that the enamel fluoride levels of the mesio-buccal and mesio-Iingual sides did not differ from that of the disto-buccal and disto-Iingual sides. The average etch depth and fluoride concentration value as calculated from the values for the two cusps per tooth were used for statistical analysis. The mean etch depths (pm) and mean enamel fluoride concentrations of alkali-washed and unwashed enamel of both erupted and unerupted teeth were tabled, together with the standard deviations and range for each etch. Contrary to the results obtained from a low F- area, no significant difference (p>O.05) could be found in the etch depth between erupted and unerupted enamel in this study. Graphs were plotted by a line fitted to the mean enamel fluoride concentration and mean etch depths values of unwashed erupted, unwashed unerupted, alkali-washed erupted and alkali-washed unerupted third molar teeth. These graphs were compared to the graphs obtained in a comparable study done by Grobler and Kotze (1990), on erupted and unerupted third molar teeth from a low fluoride area (F- < 0,10 ppm). Results indicate that the enamel fluoride concentration in the bulk of the enamel of teeth from a high fluoride area (> 1,8 ppm), is higher than that of teeth from a low fluoride area « 0,10 ppm ). In contrast to the teeth from a low fluoride area, where there was a significant increase (p<0.05) in the fluoride concentration of the outer layer (± 4 J,lm) of erupted enamel when compared to that of the unerupted enamel, no notable increase in the F- content of the enamel was observed in the present study of teeth from a high fluoride area (p>0,05). There was, in addition, no significant (p>0.05) difference between the enamel fluoride content of alkali-washed and unwashed, erupted and unerupted teeth, which showed that very little CaF 2-like material was gained by the enamel after eruption. In both studies the subjects had brushed with a fluoride dentifrice for a period of 1 - 16 years. It was expected that this topical exposure would increase the surface enamel concentration in the high fluoride area similar to the increase found in the low fluoride area. However, this was not the case, and as all the teeth from the high fluoride area exhibited some degree of fluorosis, it was concluded that posteruptive fluoride uptake by fluorotic human enamel without severe enamel loss is limited. This is in agreement with work done by Richards, Fejerskov, Baelum and Likimani (1989).

Surfactants belong to surface-active compounds that have ability to restrain the surface tension; this ability is exploited to eliminate impurities. This study is focused on determination of surfactants in waste water to which these compounds can be transported from various cleaning and washing articles. In theoretical part are listed basic classifications of surfactants, their properties and requests of Czech legislative for their content in waste water. Furthermore here are described chosen analytical procedures for determination of anion-active, cation-active and non-ionic surfactants in waste water. The conclusion of the work is evaluation of measured results of surfactants concentration in inflow and outflow of waste water from waste-treatment plant in University of Veterinary and Pharmaceutical Sciences Brno and waste water from neutralizating station in FCH BUT. To determination of anionic surfactants were used two methods, arbitration method with usage of methylene blue and mobile analytics method which is based on chemical reaction between target compound and chemical agent. This reaction leads to formation of coloured compound able to spectrofotometric determination.

The behaviour of humic acids in aqueous solutions is closely connected to the content of acid functional groups and their dissociation abilities. The titration methods are the most often used for the research of acid-base characteristics of humic acids, their results should lead to the determination of the content of functional groups and their pKa. However the determined values depend on many factors including the titration speed. The spectrophotometric determination of dissociation constant was used in this diploma thesis. Reliability of this method was confirmed in bachelor thesis where is mentioned that spectrophotometric determination of pKa corresponds with realistic dissociation behaviour of humic acids in the water much more better than values obtained from titration methods. The principle of newly used spectrophotometry method is the preparation of humic acids solutions in three different media with different pH values. Acid groups of humic acids are practically completely dissociated in intensely basic environment and the measured absorbance is caused by anion of „humate“. On the contrary their dissociation in acid environment is suppressed so much that we measure the absorbance of non-dissociated molecules of humic acids. Deionized water was used like neutral solvent. Water was replaced by acetic buffer in this thesis because of water’s properties which have significant influence on solutions' pH. Buffer was used for diluting or for solubilisation and in these both cases more stable pH values were occurred. The aim of this diploma thesis is investigate UV/VIS spectra of various solutions of humic acids with different values of pH and determinate mean value of pKa of humic acids which could be used like comparison of dissociation behaviours for vary samples. Values of acid dissociation constant were determined from measured dates and compared with values obtained by titration method. The UV/VIS spectra gained in combination with the results of pH measuring and the conductivity next showed the differences in the behaviour of differently prepared samples of humic acids.

Many new instrumentation and different instrumental techniques have been developed to deal with increasing complexity of samples encountered. Many researchers also have coupled these instrumental techniques with chemometric algorithms to assist in the quantitative analysis of multi-component samples in the hope of alleviating the need of tedious separation and cleanup procedures. These newer chemometric procedures tend to be complex and difficult to understand and implement and are successful under different circumstances and conditions. In this study, we start from the very simple beginning and examine the factors that can present difficulties with obtaining the correct results and observe how the system behaves so as to find a better and simpler chemometric procedure to perform mixture quantitative analysis. We have used simulated and actual experimental data obtained from a UV-VIS spectrophotometric measurement of metal complexes to conduct the study. Well understood and defined systems tend to give good results. The main obstacle has been, and still is, interferences in spectral information one gets from the measurement.

We are developing a new spectrophotometric temperature index based on the Ca II H and K lines. Because these lines are present even in very cool stars and because the Ca II H line is blended with the H-epsilon line in hot stars, this index should cover a very broad range of spectral types. Our data set consisted of 95 stars with spectral types ranging from O9 to M1. We examined five different indices based on the Ca II H + H-epsilon and K lines, as well as single-wavelength indices centered on each of the H-delta and H-gamma lines, which are in the same region of the spectrum. We compared our new index value with the H-beta index values for the stars in our data set that had published H-beta values. We found that the Ca II K-H index was the best temperature indicator with the widest range in magnitude of the indices we examined.

Using the Dominion Astrophysical Observatory's 1.2-m McKellar Telescope, we have obtained spectra on 81 stars from the Hyades Cluster, the Coma Cluster, and selected H-beta standard stars. These spectra cover from 4500 Å to 6900 Å which includes both the H-β and H-α absorption lines. The H-β absorption line has a long history of being used as a temperature index and more recently, calibration of an H-α index has been established for photometric observations. Through spectrophotometric comparison of temperature indices from the H-α and H-β absorption lines we find the expected strong correlation between photometric indices based on the strength of these two lines. This result confirms that the H-α index is a strong indicator of temperature.

The paper and the graphics industries use two instruments with different optical geometry (d/0 and 45/0) to measure the quality of paper prints. The instruments have been reported to yield incompatible measurements and even rank samples differently in some cases, causing communication problems between these sectors of industry.A preliminary investigation concluded that the inter-instrument difference could be significantly influenced by external factors (background, calibration, heterogeneity of the medium). A simple methodology for eliminating these external factors and thereby minimizing the instrument differences has been derived. The measurements showed that, when the external factors are eliminated, and there is no fluorescence or gloss influence, the inter-instrument difference becomes small, depends on the instrument geometry, and varies systematically with the scattering, absorption, and transmittance properties of the sample.A detailed description of the impact of the geometry on the results has been presented regarding a large sample range. Simulations with the radiative transfer model DORT2002 showed that the instruments measurements follow the physical radiative transfer model except in cases of samples with extreme properties. The conclusion is that the physical explanation of the geometrical inter-instrument differences is based on the different degree of light permeation from the two geometries, which eventually results in a different degree of influence from near-surface bulk scattering. It was also shown that the d/0 instrument fulfils the assumptions of a diffuse field of reflected light from the medium only for samples that resemble the perfect diffuser but it yields an anisotropic field of reflected light when there is significant absorption or transmittance. In the latter case, the 45/0 proves to be less anisotropic than the d/0.In the process, the computational performance of the DORT2002 has been significantly improved. After the modification of the DORT2002 in order to include the 45/0 geometry, the Gauss-Newton optimization algorithm for the solution of the inverse problem was qualified as the most appropriate one, after testing different optimization methods for performance, stability and accuracy. Finally, a new homotopic initial-value algorithm for routine tasks (spectral calculations) was introduced, which resulted in a further three-fold speedup of the whole algorithm.The paper and the graphics industries use two instruments with different optical geometry (d/0 and 45/0) to measure the quality of paper prints. The instruments have been reported to yield incompatible measurements and even rank samples differently in some cases, causing communication problems between these sectors of industry.A preliminary investigation concluded that the inter-instrument difference could be significantly influenced by external factors (background, calibration, heterogeneity of the medium). A simple methodology for eliminating these external factors and thereby minimizing the instrument differences has been derived. The measurements showed that, when the external factors are eliminated, and there is no fluorescence or gloss influence, the inter-instrument difference becomes small, depends on the instrument geometry, and varies systematically with the scattering, absorption, and transmittance properties of the sample.A detailed description of the impact of the geometry on the results has been presented regarding a large sample range. Simulations with the radiative transfer model DORT2002 showed that the instruments measurements follow the physical radiative transfer model except in cases of samples with extreme properties. The conclusion is that the physical explanation of the geometrical inter-instrument differences is based on the different degree of light permeation from the two geometries, which eventually results in a different degree of influence from near-surface bulk scattering. It was also shown that the d/0 instrument fulfils the assumptions of a diffuse field of reflected light from the medium only for samples that resemble the perfect diffuser but it yields an anisotropic field of reflected light when there is significant absorption or transmittance. In the latter case, the 45/0 proves to be less anisotropic than the d/0.In the process, the computational performance of the DORT2002 has been significantly improved. After the modification of the DORT2002 in order to include the 45/0 geometry, the Gauss-Newton optimization algorithm for the solution of the inverse problem was qualified as the most appropriate one, after testing different optimization methods for performance, stability and accuracy. Finally, a new homotopic initial-value algorithm for routine tasks (spectral calculations) was introduced, which resulted in a further three-fold speedup of the whole algorithm. / QC 20100707 / PaperOpt, Paper Optics and Colour

The complex refractive index is reported at room temperature for CdxZn1_xO thin film alloys for Cd composition up to 0.16. The CdxZn1_xO epilayers were grown by molecular-beam epitaxy on smooth ZnO/GaN/sapphire lattice templates. Transmission spectra were recorded by spectrophotometry in the 350-800nm wavelength range. The refractive index and extinction coefficient were derived by an evolutionary algorithm, which optimizes the Sellmeier and Forouhi-Bloomer dispersion models by a least-squares fitting to the experimental data.