No description available.

No description available.

Preparation of various small inorganic and organometallic complexes was completed to determine their structural characteristics and potential applications. These compounds incorporated main group and early transition metals with a range of ligands, including cyclopentadienyl rings, halides, alkoxides, amides, and allyls. Traditional solvent methods as well as solvent-free mechanochemical methods were used in the syntheses. Ball milling the dry reagents often yielded product distributions that were similar to those from reactions conducted in hexanes, and different from reactions performed in tetrahydrofuran (THF). The group 15 amide P[N(SiMe3)2]3 was prepared for the first time, and its structure, along with that of its heavier congeners (M = AsâBi), was analyzed both with X-ray crystallography and with density functional theory (DFT) methods. Structural distortions in the complexes that were evidently the result of simple steric crowding mimicked those that have been attributed to agostic interactions in lanthanide compounds. Group 4 mixed ligand species, in the form of CpmMXn(OR)4-(m+n) (X = Cl, Br; R = Me, Et, iPr, tBu) complexes, were prepared by either solvent-based or mechanochemical means. Adjustments in the molar ratios of reagents were largely reflected in the compositions of the products. The compounds containing tert-butoxide ligands displayed wide MâOâC angles, which were confirmed with DFT methods to be the result of metal-alkoxide Ï-bonding. Attempts to produce the unsolvated bis(allyl)beryllium compound [1,3-(SiMe3)2C3H3]2Be resulted instead in the generation of the potassium tris(allyl)beryllate, K[Be{1,3-(SiMe3)2C3H3}3]; it is isostructural with previously described zinc and tin analogs. The unsolvated [1,3-(SiMe3)2C3H3]2Be may be too coordinately unsaturated to be readily isolated.

The work of this dissertation investigates the chemical processes of novel materials through quantum mechanical calculations and molecular dynamics simulations. The first section of this work focuses on probing copper based metal organic frameworks (MOFs) for their ability to catalytically release nitric oxide from s-nitrosothiol (RSNO) precursors in a slow, controlled and sustained manner and compares these findings to a free copper ion/ethanol solution. Through the use of electronic structure calculations and molecular dynamics simulations, studies are carried out to better understand how the barriers of RSNOs approach to the catalytic copper center changes with modifications to the R-group (of the RSNO) and the organic linkers of the MOF. In addition to the above-mentioned work, electronic structure calculations were employed to investigate the origins of regioselectivity for silylenol ether products generated from disubstituted ketones through a unimolecular nucleophilic substitution (SN1) reaction mechanism. Synthesis of these materials is highly desired as a result of current chemistries lacking sufficient methods to steer the synthesis of natural product inspired molecules without the use of steric and electronic bias.

Master of Science / Department of Grain Science and Industry / Yong Cheng Shi / Emulsions are utilized to help control phase separation and are found in many products ranging from food to pharmaceuticals. Because of the hydrophobic properties of its functional group, octenylsuccinic anhydride (OSA) modified starch is commonly used in oil in water (o/w) emulsions. The first objective of this study was to investigate if OSA modified starch could be used in water in oil (w/o) emulsions. Experiments were designed to determine the effects of concentrations of OS starch, mineral oil and water on the stability of emulsions. High shear homogenizers and a microfluidizer were used to create stable o/w and w/o emulsions. The stability of the emulsions was examined by optical microscopy, gravitational separation, and electrical conductivity. The microfluidized samples always had a longer stability (days), no gravitational separation and did not exceed three microns, compared to the unmicrofluidized (o/w and w/o) samples. Stable (over 100 days of stability) o/w emulsions could be made without a microfluidizer if the emulsion was made of 2, 60, 38% (w/w) oil, water, starch, respectively. Stable o/w emulsions prepared with a microfluidizer were stable for over 100 days. The o/w emulsion prepared by 8, 66, 26% oil, water, and starch, respectively, was stable for over 600 days. The most stable w/o unmicrofluidized sample was made of 52, 22, 26% oil, water, starch, respectively, with a stability of 240 days. For the w/o emulsions from the microfluidizer, the most stable emulsion was made of 52, 34, 14% oil, water, starch, respectively, with a stability of 250 days. The most stable emulsion that could flow (under the 30,000 cP) was 56, 38, 6% oil, water, starch, respectively, with a stability of 150 days. The statistical mixture experiments models successfully predicted the stability for other ratios of oil, water, and starch for o/w and w/o emulsions. The second objective of the study was to determine the concentration of modified OS starch adsorbed to the mineral oil and the water phases for oil-in-water (o/w) emulsions. The percentage of the starch adsorbed at the mineral oil phase was determined and compared when different ratios of starch to oil and water were used. When the ratio of oil:starch was decreased, the emulsion particle size decreased. As the starch content increased, the percent starch adsorbed onto oil based on total oil increased. The adsorption yield and the level of starch in the emulsion did not show a trend. The surface load ranged from 1.6 to 6.98 mg/m². The sample with the highest concentration of starch (26 g/ml) had the highest surface load (6.98 mg/m²) and samples with low concentrations of starch (0.84 and 1.68 g/ml) had the second and third highest surface loads (6.82 and 4.70 mg/m², respectively). The ratio of oil:starch was increased to determine the emulsifying capacity. A high emulsifying capacity was achieved. Samples with an oil:starch ratio of 3:1 were stable for over 80 days while other samples with oil:starch ratios of 5:1 and 6:1 could be stable for one week.

Disease is characterized by signature molecular changes in affected tissues and organs. Diseases cause disruption and dysregulation of a number of biological molecules, including proteins, lipids, metal, and small molecules. Understanding the spatial distribution of biomolecules as it relates to human disease is incredibly important; it represents a way to study disease-associated changes in tissues. This work utilizes Imaging Mass Spectrometry (IMS), a discovery-based analytical approach that enables the detection of biological molecules spatially within diseased tissues, to study infectious diseases. IMS discovered molecular changes specific to areas in the tissue where pathogens interact with their vertebrate hosts. This region, deemed the pathogen-host interface, presents a wealth of information about how vertebrate hosts defend themselves from invading pathogens, including the accumulation and oxidative damage of the metal-chelating host protein calprotectin. In response to metal-starvation, bacteria also exhibit characteristic changes that are observable by mass spectrometry. Further study of these interactions is paramount to the understanding of microbial pathogenesis and to the continued treatment of infectious diseases.

Vaccines are one of the greatest public health successes; yet there is an incomplete understanding of which genes and proteins are induced by vaccines and how they contribute to the development of protective immune responses. While genomics and transcriptomics have facilitated understanding of the immune response, a systems approach including proteomics creates a more comprehensive view of vaccine responses. Most systems vaccinology studies utilize PBMCs in their analysis, which can be problematic if predominant cells overwhelm the responses of underrepresented cell types. This work outlines the development and application of a cell-based quantitative proteomic method to assess the contribution of individual cell types following influenza vaccination. First, immune cell populations (B cells, monocytes, neutrophils, natural killer cells, and T cells) were purified from blood before and after a seasonal influenza vaccination to optimize the 8-plex iTRAQ multiplexing approach. Pooling the individual cell types, rather than individual time points, resulted in the identification of more cell-type specific protein clusters whose levels changed after vaccination. Further, proteomic expression profiles and biological networks generated from purified immune cells differed significantly from PBMCs, indicating a more complete understanding of the immune response can be achieved from this method. This cell-based method was applied in a clinical trial assessing the molecular immune responses of an AS03-adjuvanted H5N1 influenza vaccine. Distinct responses were observed in all cells, but monocytes demonstrated the strongest differential signal. Immunological pathways, including MHC class I-mediated antigen processing and presentation, inflammation and oxidative stress proteins, and immunoproteasome subunits were enriched in monocytes and neutrophils after the first AS03-adjuvanted vaccine dose. These proteins were then identified as being predictive of seroprotective antibody responses 28 days after the second vaccine dose. Finally, comparison between proteomic and transcriptomic results showed little overlap, but confirmed enrichment of Class I antigen processing and presentation pathways. By investigating each individual immune cell population using quantitative proteomic methods, a more complete understanding of the complex immune response can be achieved.

No description available.

In recent years, transition metal oxides have drawn extensive attention because of their wide application in electronic, memory, battery, informatics, and optoelectronics devices. In this dissertation, we have studied two different types of oxide materials which are technologically important: LiMO 2 (M = Co, Mn, Ni), has served as cathode materials in the rechargeable battery, and LiNbO3, has wide application in ferroelectric devices such as electronics, non-volatile memories, and thin film capacitors. LiMO2 was synthesized and characterized to understand the correlation between capacity fading and thermal stability relating to the microstructures. Our results showed that delithiated (charged) LiCoO2, forms a metastable LiCo2O4 spinel phase during the ageing process, and eventually decomposes to Co3O4 over time. These two phases were identified from their magnetic responses. Paramagnetic behavior is observed in the starting material without indication of any magnetic ordering prior to heat treatment. Heat treatment of delithiated materials progressively changes the magnetic nature of the compounds. After short term heat treatment of delithiated LiCoO2, spin-glass-like or geometrically frustrated behavior is observed that suggests the formation of metastable spinel phase LiCo2O4 in the lattice. After long-term annealing, pronounced strong antiferromagnetic (AFM) ordering is observed consistent with the formation of Co3O4. The thermal stability of LiCoO2 was compared with LiMn1/3Ni1/3Co1/3O2. The result showed that, unlike LiCoO2, LiMn1/3Ni1/3Co1/3O2 does not decompose. However, selected area electron diffraction (SAED) and the bright field images from transmission electron microscopy studies revealed significant microstructure changes in the delithiated material and thermally aged products. In another system, Li[Ni1−xMnx]O2 (x = 0.3, 0.5, 0.7), the cation ordering was successfully monitored to understand the Li/Ni disorder for different compositions. This eventually determines the electrochemical capacity of these cathodes. The results on the starting materials revealed that the manganese-rich composition has more Li/Ni disorder compared to the other compositions. The Li/Ni disorder was detected by powder X-ray Diffraction, magnetic studies, as well as SAED studies. From the SAED studies, it was found that Li/Ni disorder creates x R30º type cation ordering in the transition metal layers. For delithiated materials this ordering was found to be suppressed indicating that the extraction of lithium occurs from the transition metal layer rather from the lithium layer. In another study, the ferroelectric properties of LiNbO 3 nanoparticles were studied as a function of shape. By employing a solvothermal method, cube- and sphere-like ferroelectric LiNbO3 nanoparticles were prepared by decomposition of the single-source precursor, LiNb(O-Et)6, in the absence of surfactants. X -ray diffraction showed that the LiNbO3 nanoparticles were rhombohedral (R3c) with a = 5.145(3) Å, c = 13.867(3) Å for nanocubes and a = 5.139(3) Å, c = 13.855(3) Å for nanospheres. Ferroelectric properties for these nanoparticles were also confirmed by piezoresponse force microscopy (PFM) and Raman spectroscopy. From PFM measurements, it was observed that both sets of particles exhibited polarization switching at room temperature with static d33 coefficient values of 17 pm/V for cube-like and 12 pm/V for spherical LN nanoparticles.

By modifing the procedure reported by Stone and Little, we have been able to make substituted fulvenes on a large scale and maintain good yield. Treatment of 6-tert-butylfulvene with lithium diethylamine gave, upon work-up, neopentylcyclopentadiene in 83% yield. Treatment of neopentylcyclopentadiene with n-butyllithium followed by zirconium tetrachloride gave [ƞ5-C5H4CH2C(CH3)3]2ZrCl2 in 19% yield. Treatment of 6-tert-butylfulvene with lithium 1,2,3,4-tetrahydroisoquinoline gave, upon work-up, neopentylcyclopentadiene in 71% yield- and a mixture of 3,4-dihydroisoquinoline, 1,4-dihydroisoquinoline and isoquinoline in 72% combined yield. Treatment of 6-methyl-6-phenylfulvene with dilithio-Ɩ-proline at -78 °C gave, upon work-up, a 99% yield of 1-cyclopentadienyl-1-phenylethane, 17.4% ee. Treatment of 6-methyl-6-phenylfulvene with dilithio (s)-(-)-2-pyrrolidone-5-carboxylic acid at -78 °C gave, upon work-up, a 99% yield of 1-cyclopentadienyl-1-phenylethane, 8.7% ee. Treatment of 1-cyclopentadieny-11-phenylethane (8.7% ee) with one equivalent of n-BuLi followed by treatment with lithium cyclopentadienide and ferrous chloride gave, upon work-up, [C5H5][C5H4(CH(CH3)C6H5)]Fe, 10.5% ee. Treatment of 1-cyclopentadienyl-1-phenylethane (17.4% ee) with one equivalent of n-BuLi followed by treatment with cyclopentadienyltitanium trichloride gave, upon work-up, a 48% yield of [C5H5][C5H4(CH(CH3)C6H5)]TiCl2. Treatment of 1-cyclopentadienyl-1-phenyl-ethane (17.4% ee) with one equivalent of n-BuLi followed by treatment with zirconium tetrachloride gave [C5H4(CH(CH3)C6H5)]2ZrCl2 in 78% yield. Treatment of 6-tert-butylfulvene with excess of cyclopentadienyl lithium gave, upon work-up, 1, 1-bis(cyclopentadienyl)-1-tert-butylmethane in 34% yield. Treatment of 1, 1-bis(cyclopentadienyl)-1-tert-butylmethane with two equivalent of methylmagnesium bromide or isopropylmagnesium chloride followed by quenching with D2O gave 1,1-bis(cyclopentadienyl)-l-tert-butylmethane-d2 in 56.9% and 84.1% yield respectively. Treatment of fluorenyl lithium with 6-tert-butylfulvene gave, upon work-up, a 44% yield of 1-cyclopentadienyl-1-fluorenyl-2,2-dimethylpropane as a yellow solid. Treatment of this yellow solid with two equivalent of n-BuLi followed by treatment with zirconium tetrachloride gave a 72% yield of neopentyl(cyclopentadienyl-l-fluorenyl) zirconium chloride.