>Magister Scientiae - MSc / Nanotechnology is spreading rapidly across the world as an extremely powerful technology. Nanoscience and nanotechnology are innovative scientific advancements that have been introduced only in this century. Nanotechnology has developed as the scientific advancement to grow and transform the entire agri-food area, with the potential to elevate global food production, in addition to the nutritional value, quality, and safety of food and food products. It has gained recognition due to its variability in shape, size, and dimension and how it correlates to its possibilities. One of those functions is nanoparticles’ (NPs) ability to have antimicrobial activity, more specifically its antifungal activity. One particular pathway of synthesising NPs is through phytonanotechnology which is the use of biomaterial to synthesis the NPs. / 2024

DOCTORAL THESIS ABSTRACT 2-Oxazoline triblock copolymers with hydrophilic, lipophilic and fluorophilic blocks: from synthesis to hierarchical self-assembly MSc. Leonid Kaberov The focus of this research was on the study of di- and triblock poly(2-oxazoline) copolymers with fluorinated blocks. The synthesis and solution properties of novel copolymers combining hydrophilic, hydrophobic (lipophilic) and fluorophilic moieties into one segmented molecule were reported. The simple synthetic approach which provides an easy way to attach a CnF2n+1 terminal chain to a poly(2-methyl-2-oxazoline)-block-poly(2-n-octyl-2-oxazoline) copolymer was described. Small-angle neutron and x-ray scattering experiments unambiguously proved the existence of polymersomes, worm-like micelles and their aggregates in aqueous solution. It was shown that increasing content of fluorine in the poly(2-oxazoline) copolymers results in a morphological transition from bilayered or multi-layered vesicles to worm-like micelles. The synthesis of poly(2-perfluoroalkyl-2-oxazoline)s is complicated by their extremely low activity in cationic ring-opening polymerization reaction (CROP), both in the initiation and in the propagation due to strong electron-withdrawing effect of perfluoroalkyl substituent. A detailed systematic study on synthetic...

<p>Multiphase fields find wide applications in the fields of combustion, sprays, turbomachinery, heating and cooling systems, blasts, energetic materials, and several more areas of engineering interest. As the efficiency and performance of these systems depend heavily on the underlying multiphase field, studying their intricate structural features becomes important. The current study follows the development of a three-dimensional Wide-Angle Relay Plenoptic (WARP) imaging system with two image quadruplers for the tomographic imaging of multiphase fields. 3D printed targets were used to simulate both semi-transparent as well as opaque particle fields to emulate multiphase systems. Tomographic reconstruction of the targets was performed using the iterative MART reconstruction algorithm in a commercial image processing software. Reconstructions were performed at different angular separations between the cameras as well as for varied separation distance between the object and the imaging system. Quantitative analysis of the reconstruction quality of the developed system was performed to study the effectiveness and accuracy of this system in imaging multiphase fields. The effect of varying different system parameters on reconstruction quality has been studied to evaluate the best system configuration for imaging multiphase fields.</p>

Surfactants self-assemble into aggregates above a certain concentration. In this work mixtures of the cationic surfactant cetyltrimetylammonium bromide (CTAB) and the anionic surfactant sodium octyl sulfate (SOS) were investigated systematically. The measurements were accomplished by combining the two complimentary techniques static light scattering (SLS) and cryo-transmission electron microscopy (CRYO-TEM). It was found that CTAB-rich samples contain large threadlike micelles rather close to mole fractions where vesicles start to form. The mole fraction x of the surfactant in excess in the aggregates was calculated and it was found that it differs a lot from the mole fraction in the bulk, and the transition from micelles to vesicles occurs when x is about 0.7. In the SOS-rich samples small globular micelles were observed that transform into vesicles upon dilution. Some of the samples rich in SOS were found to contain open vesicles with CRYO-TEM and the reasons for this behavior have been discussed. One question that needs to be further investigated is whether or not these structures are the result of some kind of distortion of the equilibrium process during sample preparation in connection with CRYO-TEM measurements. In most cases the two methods showed consistent results and trends, but for some samples differences could be observed.

This dissertation is dedicated to the complete structural elucidation of chain-walking polyethylene (CWPE) using state-of-the-art analytical technology, including light and neutron scattering experiments as well as advanced liquid chromatography. In doing so, the structural characteristics of CWPE shall be determined on global and segmental scale in order to clearly differentiate this material class from other classical types of PE. Moreover, it is aimed to clarify the true potential of CW catalysis including possibilities and limitations.

No description available.

The health and viability of cells and tissues in the human body depend on the functional integrity of proteins. A small number of long-lived proteins, including the crystallins in the lens of the eye, evade protein turnover, a typical cellular mechanism for repair and regeneration, and remain extant throughout life. The cumulative effect of post-translational modifications on the structure, function, and conformation of these long-lived proteins records the history of molecular aging in an individual. Along with absence of protein turnover, the optical accessibility, transparency, and age-related spatial order make the lens an ideal target for in vivo assessment of molecular aging. Accordingly, this doctoral thesis investigated the hypothesis that age-related perturbations that alter the protein environment in the human lens can be detected and monitored as a quantitative biomarker of molecular aging detectable by quasi-elastic light scattering (QLS). To test this hypothesis, QLS was applied in vitro and in vivo to study time-dependent changes in lens proteins. Water-soluble human lens protein extract was used in vitro as a model system that mimics the lens fiber cell cytoplasm. The effects of long-term incubation (nearly one year, proxy for aging), oxidative stress, ionizing radiation, metal-protein and pathogenic protein-protein interactions were investigated by QLS as a function of time. In vitro results were validated by protein gel electrophoresis and transmission electron microscopy. In vivo, age-dependent changes in lens proteins were assessed in healthy subjects across a broad age-range (5–61 years of age). Pathogenic protein aggregation in the lens was examined in vivo using Down syndrome (DS) subjects, a common chromosomal disease associated with an age-related Alzheimer’s disease (AD)-linked lens phenotype. Results obtained from the in vitro studies noted, for the first time, QLS detection of long-term supramolecular changes in a complex lens protein model system. Our FDA-approved QLS device was successful in assessing age-dependent lens protein changes in a clinical study at Boston Children’s Hospital (BCH). In two landmark studies conducted at BCH, we detected statistically significant AD-related lens protein changes in DS subjects aged 10–20 years, when compared with age-matched controls. These studies are the first clinical application of QLS in DS, and demonstrate protein changes in DS earlier than any previously reported studies. Due to the discrepancy in chronological and biological age and the lack of an objective index for the latter, we propose the application of QLS in the human lens as a quantitative biomarker of molecular aging.

Influence of the preparing of a biopolymer-surfactant system on its solubilization properties and stability was investigated by using fluorescence spectroscopy and dynamic light scattering methods. Investigation was made on complex of native hyaluronan with cationic surfactant cetyltrimethylammonium bromide (CTAB). System has been studied in aqueous and in saline solutions. The effect of temperature of stock solutions and freezing effect on subsequent properties were investigated. Further was examinated, what effect has a way of introducing fluorescent probe into the system on subsequent solubilization properties. It was found that the conditions of preparing of biopolymer-surfactant system have a significant effect on the solubilization properies and stability of complex.

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第20710号 / 工博第4407号 / 新制||工||1685(附属図書館) / 京都大学大学院工学研究科高分子化学専攻 / (主査)教授 古賀 毅, 教授 吉崎 武尚, 教授 竹中 幹人 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM

The use of spectrofluorometers to examine nanomaterials is quite popular using either fluorescence or synchronous measurements. However, understanding how a material’s optical properties can influence spectral acquisition are of great importance to accurately characterize nanomaterials. This dissertation presents a series of computational and experimental studies aimed at enhancing the quantitative understanding of nanoparticle interactions with matter and photons. This allows for more reliable spectrofluorometer based acquisition of nanoparticle containing solutions. Chapter I presents a background overview of the works described in this dissertation. Correction of the gold nanoparticle (AuNP) inner filter effect (IFE) on fluorophore fluorescence using PEGylated AuNPs as an external reference method is demonstrated in Chapter II. The AuNP IFE is corrected to quantify tryptophan fluorescence for surface adsorbed proteins. We demonstrate that protein adsorption onto AuNPs will only induce ~ 20% tryptophan fluorescence reduction instead of the commonly assumed 100% reduction. Using water Raman intensities to determine the effective path lengths of a spectrofluorometer for correction of fluorophore fluorescence is discussed in Chapter III. Using Ni(NO3)2 and K2Cr2O7 as Raman IFE references, the excitation and emission path lengths are found to exhibit chromophore and fluorophore independence, however path lengths are spectrofluorometer dependent. Finally, ratiometric resonance synchronous spectroscopy (R2S2) is discussed in Chapter IV. Using a combination of UV-vis and R2S2 spectroscopy, the optical cross sections of a wide range of nanomaterials were determined. Also on-resonance fluorescence in solution is demonstrated for the first time. The nanoparticles discussed range from photon absorbers, scatterers, simultaneous photon absorbers and scatterers, all the way to simultaneous photon absorbers, scatterers, and emitters.