Thesis (Ph. D.)--University of Washington. / Vita. Bibliography: L. [65].

Thesis (Ph. D.)--University of Chicago, 1941. / Reproduced from type-written copy. "Literature cited": p. 15.

Univ., Diss--Princeton.

The thermal conductivity of three crystals of cesium iodide ranging in size from three to eight millimeters diameter was measured in the temperature range 1.15°K to 5.40°K. Thermal conductivity measurements were made using the thermal potentiometer method. Differences in the thermal conductivity of the three samples were interpreted in terms of phonon scattering from the boundaries of the crystals, and from internal structure defects. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

<p>During bio-technical processing it is important to monitorbiological parameters such as cell growth, viability andproduct formation. Many of the analyses traditionally used areslow to perform and provide only average data for thepopulation. Flow cytometry is a laser-based technique, whichmeasures physical properties of a cell in a flowing stream, ata rate of several thousand cells per second. It offers theprospect of an at-line, multi-parameter analysis of individualmicroorganisms in a population.</p><p>In this project several methods for at-line measurements ofbioprocesses were developed such as protocol's for measuringcell concentration, viability and product formation. Theprimary focus was on prokaryotic organisms (<i>E. coli</i>) but eukaryotic organisms (<i>P. pastoris</i>) were included.</p><p>The possibility to use volumetric cell counting to measurecell concentration (cell number) was evaluated. It was shownthat the method was applicable for high cell density processesof both<i>E. coli</i>and<i>P. pastoris</i>.</p><p>The combination of Bis- (1,3-dibutylbarbituric acid)trimethine oxonol (depolarised membranes) and propidium iodide(loss of membrane integrity) as fluorescent markers was usefulto measure viability at-line of cells in high cell densityprocesses. The protocol was shown to be reproducible for<i>E. coli</i>and<i>P. pastoris</i>.</p><p>The viability staining was used to study the kinetics ofweak organic acids (food preservatives). The protocol provideddata about cell functions such as membrane depolarisation andloss of membrane integrity caused by introducing weak organicacids to shake flask cultures of<i>E. coli.</i></p><p>Labeling inclusion bodies with fluorescent antibodiesprovided a method, which could specifically monitor theincreased accumulation of recombinant promegapoetin proteinwith process time. This technique was further developed forintracellular staining by application of a permeabilising stepbefore labeling with antibodies. Staining of inclusion bodiesdirectly inside permeabilised cells gave information about thedistribution of protein expression in the cell population.</p><p>In conclusion, flow cytometry provides an at-line, singlecell technique for measurement of several biological parametersin bioprocesses.</p><p><b>Key words</b>: flow cytometry, Partec PAS, propidium iodide(PI), bis- (1,3-dibutylbarbituric acid) trimethine oxonol(BOX), Alexa fluor 488, bioprocess,<i>E. coli</i>,<i>P. pastoris</i>, inclusion body, food preservatives,viability, membrane potential</p>

Potable water is a necessity and unfortunately, it can be contaminated in many different ways. This paper specifically addresses the case scenario when, water has been contaminated by radionuclides. The mucilage of Opuntia ficus-indica (OFI), has been proven to be a great flocculating agent, turbidity reducer, crude oil dispersant and an environmentally friendly substance as an absorbent of water contaminants. In this work, the OFI mucilage was investigate to evaluate its capacity to separate radioactive ions from water. The surrogate approach is modeled based on water studies performed by Willi A. Brand, who proved that radioactive isotopes behave similar to their stable isotope, which can be easily experimented on without running the risk being exposed to radioactive harm. The surrogate model was used in conjunction with a trial and error method to determine optimum removal of Iodine and Cesium. A wide range of OFI concentrations and pH values were tested, which allowed for the determination of the optimal conditions for which cactus mucilage can remove the desired elements. The cactus mucilage is acidic by nature and experiments were performed to determine if its performance is affected by the changes in pH. This work is one of its kind in which a natural material can be used to remove potentially harmful radioactive ions from water.

In organometallic chemistry, metal complexes bearing unsaturated hydrocarbon ligands are of extensive interest, especially the C3H3-M system which includes propargyl (HC¡ÝCCH2-M), allenyl (H2C=C=CH-M), and acetylide (H3CC¡ÝC-M) forms. To study the chemistry of these species on metal surfaces, we used proprargyl bromide (HC¡ÝCCH2-Br) as precursor to produce C3H3(ad) on Ag(111) under ultrahigh vacuum (UHV) conditions. The thermal reactions pathway was investigated by Temperature-Programmed Desorption (TPD), and Reflection-Absorption Infrared Spectroscopy (RAIRS). In addition, density functional theory (DFT) calculations were conducted to obtain the optimized geometry for the adsorbates, and the computed IR spectra facilitated the vibrational mode assignments. TPD spectra showed that hydrogenation products C3H4 evolved at 310 K and 475 K. However, the desorption peak at 310 K was broad, indicating that more than one species were encompassed. Besides the hydrogenation product, a coupling product C6H6 (2,4-hexadiyne) was also unveiled as part of the desorption feature at 475 K. The identity of the possible C3H4 hydrogenation products (propyne and/or allene) was not discriminable by the mass spectrometry. The problem was circumvented by using £\,£\-dimethyl-substituted propargyl chloride because this dimethyl-substituted species also resulted in hydrogenatioin products around 310 K and 475 K, respectively; and the corresponding allenic and acetylenic end-products are distinguishable by the mass spectrometry. The results indicated that the broad feature at 310 K, in fact, contained both allene (lower temperature) and propyne (higher temperature), whereas the hydrogenation product at 475 K was propyne. The RAIR spectrum at 200 K showed that all C3H3(ad) on Ag(111) readily took on the allenyl form after the C-Br bond scission. It is thus obvious that allene at 310 K was generated by adding one hydrogen to the £\-carbon of the surface allenyl. RAIR spectroscopy revealed a drastic change after annealing the surface to 250 K, where the spectrum was almost identical to that obtained from using propynyl iodide (H3C-C¡ÝC-I) as a direct source for methylacetylide (H3C-C¡ÝC-Ag). Consequently, the products of propyne and 2,4-hexadiyne could be reasoned out.

München, Universität, Thesis (doctoral), 2001.

No description available.

Thesis (Ph. D.)--University of Michigan, 1928.