Browsing by Subject "analysis"

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  • Omoruyi, I.M.; Pohjanvirta, R. (2018)
    Mounting evidence of the effects of endocrine-disrupting chemicals (EDCs) in humans has led to assaying a vast array of food items (processed or packaged) as possible sources of human exposure to estrogens. In this study, we investigated the current situation in this respect of different food supplements and beer brands. Eleven food supplements and 24 beer brands were obtained from Helsinki, Finland. Sample preparation was carried out by established methods while estrogenic activities were assessed by a yeast bioluminescent assay, using two recombinant yeast strains (Saccharomyces cerevisiae BMAEREluc/ERα and S. cerevisiae BMA64/luc). All the food supplements as well as 81% of the beer samples tested were found to be estrogenic, with estradiol equivalent concentrations of food supplements and beer brands ranging from 7.5 to 11.5 µg/ml and from below detection limits to 43.6 ng/ml, respectively. The estrogenic activities detected in beer samples were not dependent on the beer's alcoholic content, the country of production, or the size of the production brewery. The results of our study imply that both food supplements and beers can be a significant source of human exposure to estrogens. Therefore, further studies and regular surveillance are warranted. © 2018, © 2018 Taylor & Francis Group, LLC.
  • Ritola, Ville (Helsingfors universitet, 2016)
    Background. Knowing what a psychological test measures and if it works the same way in different contexts, i.e. has measurement invariance (MI), is crucial for its valid and reliable use. The Wechsler Adult Intelligence Scale – Fourth Edition (WAIS-IV) was published in Finland in 2012. However, recent research suggests that the factor model given in the WAIS-IV test manual and the information regarding MI between different age groups and levels of education are lacking. Methods. This study employed the normative sample of the Finnish WAIS-IV. First, the factor model in the manual was examined and improved using confirmatory factor analysis with a mixed data-theory approach. Second, the new model was tested for strict residual MI for different age groups and levels of education, in order to study if the test reaches an acceptable level of MI. Results and conclusions. The results indicated that the normative data is best modeled by an oblique non-g model. The study also replicated a Spatial Visualization factor with loadings from Block Design, Visual Puzzles and Picture Completion, and Quantitative Reasoning factor with Figure Weights and Arithmetic. A previously unmentioned link in factor analytic literature on WAIS-IV was found between Block Design and Processing Speed factors. The results questioned the link between Arithmetic and Verbal Comprehension factor and found the underlying source of shared variance to be links between Information and Arithmetic, which was interpreted as Educational Achievement. WAIS-IV reached strict residual MI for both different age groups and levels of education. The study offers a more accurate factor model of WAIS-IV and gives confidence that psychologists can reliably apply it over different ages and levels of education in the normal population of Finland.
  • Gregson, Barbara A.; Broderick, Joseph P.; Auer, Ludwig M.; Batjer, Hunt; Chen, Xian-Cheng; Juvela, Seppo; Morgenstern, Lewis B.; Pantazis, George C.; Teernstra, Onno P. M.; Wang, Wen-Zhi; Zuccarello, Mario; Mendelow, A. David (2012)
  • Kalliala, Mari (2005)
    During the 1990s there was a worldwide decline in the number of terrorist attacks, whereas political crime in general increased in most Western liberal democracies. The study analyses the emergence of radical alternative movements in Finland in the 1990s and their illegal underground activities as a phenomenon of the late modern risk society. Since reflexivity is an essential feature of late modernity, the study also discusses ways in which law enforcement can manage risks posed by political crime. Secrecy influences the character of radical alternative movements. In the context of late modern social flux they are better understood as communitarian movements than social ones. Belonging to the community is more important to their supporters than the activities of the community. Furthermore, radical alternative movements consist of beliefs non-typical to mainstream society. They are part of the so-called cultic milieu - the dynamics of which is influenced by its relationship to mainstream society and the ideology of 'seeking'. Finnish society in the 1990s provided a fertile breeding ground for the emergence of radical movements and illegal underground activities. However, international influences which were adopted played a significant role. Radical alternative movements did not have to subscribe to illegal underground activities since their political agenda was not illegitimate. Illegal underground activities were organised based on the strategy of leaderless resistance. Nevertheless, structures had to be created to provide for resources and to mobilise illegal underground activities. The refrain of violence against persons was the most important strategic choice. For instance, it prevented the use of effective law enforcement counter-measures. However, no short or long-term political goals were achieved by illegal means. The tactics seemed to have served mainly organisational maintenance. Illegal underground activities impinge directly upon the rights and liberties of others. However, balancing between liberty and order is a major challenge as democratic values are preserved by adopting the very means that tend to subvert them. Analysis is a new tool for law enforcement and can be used to assess threats and risks, set priorities and formulate counter-strategies.
  • Taivainen, Sanna (Helsingfors universitet, 2016)
    Suspension is nowadays the most commonly used dosage form in preclinical animal studies. However, suspension can be physically unstable and changes in particle size or crystal form of an active pharmaceutical ingredient (API) can occur during storage. Conventionally suspensions are also prepared in a mortar, and hence the quality of suspensions is operator-dependent. One of the aims in this study was to prepare suspensions using a mortar and pestle and an Ultra-turrax homogenizer to find out how the preparation method affects the particle size of suspension. A solution containing methylcellulose and Tween 80 was used as a vehicle, and five active APIs with different physico-chemical properties as model drugs. Moreover, an aim of the study was to evaluate the stability of the suspensions stored at room temperature and in the refrigerator and freezer by physical (laser diffraction, optical microscopy, X-ray powder diffraction) and chemical (high-performance liquid chromatography) methods of analysis. The aim of the study was also to assess and compare the suitability of laser diffraction and optical microscopy for the determination of partice size during preclinical studies. The suspensions prepared using a mortar and pestle and Ultra-turrax had a similar particle size in almost all cases. The particle size of API that was difficult to grind decreased significantly, also when using Ultra-turrax although the capacity used was minimum. Both prepation methods had the best repeatability of particle size when the API was easy to grind. However, Ultra-turrax could provide better homogeneity of quality than a mortar and pestle if the settings were optimized. The effect of different operators was not studied in this study. The stability of suspensions in different storage conditions was dependent on the properties of API. The particle size of all frozen suspensions decreased after two days based on laser diffraction results. Although the reason was not found from literature or supplementary tests (particle size analysis of the vehicle and pH-measurements), freezing of suspensions should be treated with caution based on this study. The crystal structures of APIs remained stabile with the exception of typical disproportionation of the API salt. Suspensions were mainly chemically stabile in all conditions, but water-solubility of API seemed to decrease stability. The micellar solubilization of drugs was also observed. The best way to determine the particle size of preclinical suspensions proved to be the combination of laser diffraction and optical microscopy images. The microscopy images confirmed the validity of the size distributions measured by laser diffraction and provided information about e.g. particle aggregation. On the other hand, optical microscopy image analysis was not suitable method for particle sizing.
  • Kokkala, Katja (Helsingfors universitet, 2010)
    The characteristics of macrolides are discussed in general level in the theoretical part of this Master's thesis. The discussion is focused on the properties of two macrolides in molecular level and their tendency to form tautomeric forms highlighting the structural similarities and differences of these macrolides, which will affect both the mechanisms of action and the metabolism. Attention is also paid to biosynthesis and manufacturing process keeping focus on downstream process, especially the impurities, which arise from the macrolide biosynthesis. Also the principles of argentation chromatography are discussed. In the experimental part of Master's thesis a purification method for one macrolide was developed using argentation chromatography. Conventional chromatographic purifications cannot separate the macrolide from its impurities. The purity of the macrolide after argentation chromatography was 98.6%. Also a new crystallization method was developed, which produces anhydrous form of the macrolide instead of traditional monohydrate form. A method for analysing the macrolide using HPLC was developed. The method was validated according to ICH guidelines. The tautomeric forms and the impurities of the macrolide were analysed using LC/MS. One of these impurities was isolated and analysed with NMR thus confirming its identity. An analysed NMR spectrum of this impurity has not been published according to our best knowledge. A previously unknown impurity was identified based on MS analysis and retention time.