Thesis (MSc)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: Impact polypropylene copolymers (IPC) are commercially used in a variety of applications. They are very complex materials and extensive studies have been conducted to understand the relationship between their chemical structure, morphology and impact properties. The distribution of ethylene propylene rubber (EPR) within IPC has drawn much attention but visualization of the morphology is difficult. In this study a fluorescent marker was used to probe the distribution of EPR within the crystalline and semi-crystalline fraction. The EPR was removed from a commercial IPC and labelled with a fluorescent marker. In this study a method utilizing the hydrophilic nature of cellulose nanowhiskers (CNW) was developed to label the EPR. CNW were labelled with fluorescein-5’-isothiocyanate (FITC) and rhodamine B (RhB) using a one-step procedure. The labelled CNW were incorporated into the EPR by means of sonication. The mobility of the labelled CNW within the EPR film was investigated by confocal fluorescence microscopy (CFM), and showed that the labelled whiskers did not move within the EPR, thus substantiating the validity of this approach. The labelled EPR was recombined with the crystalline fraction by means of injection moulding and was analysed by CFM, and the distribution of the labelled EPR was evaluated. Confocal fluorescence microscopy showed an even distribution of the labelled rubber throughout the injection moulded sample. The miscibility of two EPRs within the IPC matrix in the melt was also investigated using this technique. CFM showed that the technique has promise to prove miscibility or the lack thereof when chemically similar materials are combined in the presence of morphologically different matrix materials. / AFRIKAANSE OPSOMMING: Impak polipropileen kopolimere (IPK) word kommersieel gebruik in ‘n wye reeks produkte. Die samestelling van hierdie kopolimere is baie ingewikkeld en uitgebreide studies is al gedoen om hul chemiese samestelling op molekulêre vlak te verstaan. Baie studies met betrekking tot die verspreiding van die etileen-propileen rubber (EPR) binne in hierdie impak polipropileen kopolimere is al gedoen, maar visualisering van die morfologie is moeilik en beperk. Hierdie kennis kan bydra tot die verbetering van hul chemiese eienskappe en toepassings. In hierdie studie word ʼn fluorosserende merker gebruik om die verspreiding van die EPR binne die kristallyne en semikristallyne fraksie te ondersoek. Die EPR is verwyder vanuit 'n kommersiële IPK en is gemerk met 'n fluoresserende merker. In hierdie studie is 'n metode ontwikkel om die EPR te merk deur gebruik te maak van die hidrofiliese eienskap van sellulose nanovesels (SNV). Die SNV is gemerk met fluoressien-5'-isotiosianaat (FITC) en rhodamien B (RhB) met behulp van 'n eenstap proses. Die gemerkte SNV is deur middel van sonikasie in die EPR versprei. Die mobiliteit van die gemerkte SNV binne-in die EPR film is ondersoek deur gefokusde fluoressensie mikroskopie (GFM) en het getoon dat die gemerkte vesels nie binne die EPR beweeg nie. Dit bevestig dus die geldigheid van hierdie benadering. Die gemerkte EPR is herkombineer met die kristallyne fraksie deur middel van spuitgiet en is geanaliseer deur GFM en die verspreiding van die gemerkte EPR is geëvalueer. GFM het 'n eweredige verspreiding van die gemerkte rubber regdeur die moster wat gespuitgiet is getoon. Die mengbaarheid van twee EPRs binne-in die IPK matriks is ook ondersoek deur gebruik te maak van hierdie tegniek. GFM het getoon dat hierdie tegniek waarde inhou om te bewys dat twee produkte mengbaar is of nie, al word hulle geherkombineer word met ‘n matriks wat morfologiese van hul verskil.

published_or_final_version / Pathology / Master / Master of Medical Sciences

Multicolor fluorescence in-situ hybridization (M-FISH) techniques provide color karyotyping that allows simultaneous analysis of numerical and structural abnormalities of whole human chromosomes. Chromosomes are stained combinatorially in M-FISH. By analyzing the intensity combinations of each pixel, all chromosome pixels in an image are classified. Often, the intensity distributions between different images are found to be considerably different and the difference becomes the source of misclassifications of the pixels. Improved pixel classification accuracy is the most important task to ensure the success of the M-FISH technique. Along with a reliable pixel classification method, automation of the karyotyping process is another important goal. The automation requires segmentation of chromosomes, which not only involves object/background separation but also involves separating touching and overlapping chromosomes. While automating the segmentation of partially occluded chromosomes is an extremely challenging problem, a pixel classification method that satisfies both high accuracy and minimum human intervention has not been realized. The main contributions of this dissertation include development of a new feature normalization method for M-FISH images that reduces the difference in the feature distributions among different images, and development of a new decomposition method for clusters of overlapping and touching chromosomes. A significant improvement was achieved in pixel classification accuracy after the new feature normalization. The overall pixel classification accuracy improved by 40% after normalization. Given a cluster, a number of hypotheses was formed utilizing the geometry of a cluster, pixel classification results, and chromosome sizes, and a hypotheis that maximized the likelihood function was chosen as the correct decomposition. Superior decomposition results were obtained using the new method compared to the previous methods. Contributions also include development of a color compensation method for combinatorially stained FISH images (including M-FISH images) based on a new signal model for multicolor/multichannel FISH images. The true signal was recovered based on the signal model after color compensation. The resulting true signal does not have color spreading (channel crosstalk) among different color channels. Two new unsupervised nonparametric classification methods for M-FISH images are also introduced in this dissertation: a fuzzy logic classifier and a template matching method (a minimum distance classifier). While both methods produce an equivalent accuracy compared to a supervised classification method, their computation time is significantly less than a Bayes classifier. Highly sophisticated and practical algorithms have been developed through this research. Using the developed methods, the amount of human intervention required will be significantly reduced: chromosomes are reliably and accurately segmented from the background, pixels are accurately classified, and clusters of overlapping and touching chromosomes are automatically decomposed. / text

<p>This Licentiate thesis presents research accomplished at theSection of Atomic and Molecular Physics at the Royal Instituteof Technology in Stockholm using photon induced fluorescencespectroscopy (PIFS) during the last two years.</p><p>The main results presented are summarized:</p><p>- Neutral photodissociation in CO was observed aftersynchrotron photon excitation in the range 19-26 eV bycollecting dispersed fluorescence from excited neutral C atoms.Follow-up ab initio calculations point out CO Rydberg seriesconverging to the CO+ C and D states as precursors.</p><p>- The branching ratio between N2 + (B-X)(v’=1,v’’=2) and (v’=0,v’’=1)transitions in the 20-46 eV energy range reveals strongnon-Franck-Condon effects. Ab initio calculations indicate thatthe autoionization of certain superexcited states areresponsible for some of the structures present in the branchingratio curve, confirming the important role of non-Rydbergdoubly excited resonant states (NRDERS) in de-excitationprocesses above the ionization potential.</p><p>- Photon induced neutral dissociation processes in NO arereported. Neither Rydberg series nor other molecular states inNO known so far can account for the collected data. From abinitio calculations more information regarding the NO precursorstates and the mechanism behind the observed neutraldissociation were obtained.</p><p>- The details of a new experimental set-up for gas phasefluorescence measurements using synchrotron radiation aredescribed. It is able to perform simultaneous measurements ofdispersed and total fluorescence in the visible range. Thefirst results obtained with this set-up are presented,concerning fluorescence after excitation of the N2 molecules inthe N 1s edge.</p><p>These four studies conform the set of papers enclosed in theLicentiate thesis.</p><p>Finally a pre-study to further apply PIFS to speciespreviously excited by microwave discharge is included as futureplans.</p>

The research described in this dissertation is the first evaluation and application of a new class of optical detectors, two-dimensional charge-coupled device (CCD), for low-light level chemiluminescence and other luminescence spectroscopies. This research conclusively demonstrates the superior qualitative and quantitative performance of spectrometric systems which employ these detectors. It is experimentally shown that a single detector element of a CCD has comparable or superior sensitivity to the most sensitive single channel detectors; photomultiplier tubes (PMT). The results from the application of the CCD detector system to molecular spectroscopies (fluorescence, chemiluminescence, fluorescence detection of high performance liquid chromatography (HPLC) effluents, and chemiluminescence detection of HPLC effluents) and atomic spectroscopies (spatially and spectrally resolved spark and direct current plasma are presented). The results of operating the CCD in specialized readout modes developed in this research termed charge dependent variable binning (CDVB), simultaneous variable binning (SVB), and continuous high speed spectral framing (CHSF) are described and applied. The CDVB and SVB techniques allow very sensitive quantitation of spectrally resolved and unresolved signals with very wide dynamic ranges without prior knowledge of the signal intensity. Finally, CHSF technique provides spectrally resolved temporal study of extended period luminescence emission with millisecond time resolution. The results of unique algorithms to restore the integrity of the image obtained with a two-dimensional CCD detector are described and applied. The algorithms implemented are for removing variations in detector sensitivity and responsivity and spectrometer efficiency, as well as providing digital image filtering.

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