Atmospheric aerosols may be emitted directly as particles (primary) or formed from gaseous precursors (secondary) from different natural and anthropogenic sources. The highly populated South and East Asia regions are currently in a phase of rapid economic growth to which high emissions of carbonaceous aerosols are coupled. This leads to generally poor air quality and a substantial impact of anthropogenic aerosols on the regional climate. However, the emissions of different carbon aerosol components are still poorly constrained. Water-soluble organic carbon (WSOC) is a large (20-80%) component of carbonaceous aerosols that can absorb solar light and enhance cloud formation, influencing both the direct and indirect climate effects of the aerosols. A novel method for carbon isotope-based studies, including source apportionment, of the WSOC component of ambient aerosols was developed and tested for recovery efficiency and the risk of contamination using both synthetic test substances and ambient aerosols (paper I). The application of this method for the source apportionment of aerosols in South and East Asia shows that fossil fuel input to WSOC is significant in both South Asia (about 17-23%) highly impacted by biomass combustion practices and in East Asia (up to 50%) dominated by fossil energy sources (papers II, III, IV). Fossil fraction in WSOC in the outflow from northern China is considerably larger than what has been measured in South Asia, Europe and USA (paper IV). A trend of enrichment in heavy stable carbon isotopes in WSOC with distance the particles have been transported from the source is observed in the South Asian region (papers II, III). Dual-isotope (Δ14C and δ13C) analysis demonstrates that WSOC is highly influenced by atmospheric aging processes. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3: Manuscript. Paper 4: Submitted.</p>

Anthraquinone (AQ) derivatives with relatively high reduction potentials have been synthesized to afford good candidates for electron transfer studies in DNA. Electron withdrawing groups on the anthraquinone ring gave derivatives with less negative reduction potentials. The anthraquinone imide (AQI) derivatives had reduction potentials less negative than AQ derivatives. The AQI ring system was subject to base-induced hydrolysis. Water-soluble sulfonated tetraarylporphyrins have been studied in a wide variety of contexts. Herein, we report the first synthesis of a pentasulfonated porphyrin bearing an internal cyclic sulfone ring. Treatment of 5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrin (TPPS4) with fuming H2SO4 gave a structure consistent with initial sulfonation followed by dehydration to give a sulfone bridge between an ortho-position of one of the phenyl groups and a β-pyrrole position on the porphine ring (TPPS4Sc). The structure was established by ESI-MS and 1HNMR. The Soret absorption is red shifted by about 32 nm compared to that of TPPS4. Streptococcus pyogenes obtains iron by taking up heme from the environment during infection. One of the heme uptake pathways is the Sia or Hts pathway. The initial protein in this pathway is Shr, which has two heme-binding NEAT domains, NEAT1 nearer the N-terminus, and NEAT2 nearer the C-terminus. We report biophysical characteristics of these two NEAT domains. To assess stability of this domain towards heme release, denaturation studies of the Fe(II) and Fe(III) forms were performed. For each domain, both the Fe(II) and the Fe(III) forms behave similarly in thermal denaturation and guanidinium denaturation. Overall, NEAT2 is more stable than NEAT1. Spectral signatures, sequence alignment and homology modeling for both domains suggest that one of the axial ligands is methionine. NEAT2 autoreduces as the pH increases and autooxidizes as the pH decreases. Heme uptake from the host environment is the only iron acquisition pathway in S. pyogenes; inhibition of this pathway might be an approach to infection control. Compounds that might inhibit the heme uptake pathway were selected via virtual screening.

New methodologies for the efficient syntheses of 4,4-difluoro-4-bora-3a,4adiaza- s-indacenes (BODIPYs) and rosamines were developed. A serendipitous discovery led to a new reaction which afforded BODIPYs in high yields. Systematic studies of the kinetics and mechanisms of the new reaction were performed. A series of BODIPYs were successfully prepared using the new approach. A simple and efficient synthesis of rosamines with cyclic-amine substituents was devised. These new rosamines showed interesting anti-tumor activities. Several types of novel fluorescent compounds were prepared. Highly fluorescent GFP-chromophore analogs were designed and synthesized. The correlation between the optical properties and the structures was investigated. New pyronin dyes with mesoheteroatom substituents were efficiently prepared. The fluorescence properties of these compounds were highly dependent on the nature of the meso-substituents. A set of BODIPY dyes that fluoresce brightly above 600 nm were made. They were then used as acceptors to prepare water-soluble through-bond energy transfer cassettes. All the cassettes had complete energy transfer and high quantum yields in MeOH. A few also had good fluorescence properties in aqueous media and even on proteins. The through-bond energy transfer cassettes were used to monitor protein-protein interactions. In order to test our hypothesis, an artificial protein interaction system was built by utilizing the biotin/(strept)avidin interactions. Thus Atto425-BSA-biotin, streptavidin-cassette1 and avidin-cassette2 were prepared. The interactions between Atto425-BSA-biotin and cassette labeled (strept)avidin were successfully detected in vitro and in living cells by fluorescence techniques.

Poly(p-phenylenebenzobisimidazole), PBI, is a rigid-rod polymer with a fully conjugated backbone having superior mechanical properties, thermo-oxi- dative and solvent stabilities. The stabilities cause processing difficulties and in terms limit its applications in critical technologies, such as conducting polymers, nonlinear optics, and solid polyelectrolytes. In this study, a chemical derivative of PBI, poly[1,7-dihydrobenzo[1,2- d:4,5-d¡¦]diimidazo-2,6-diyl[2-(2-sulfo)-p-phenylene]], sPBI, was synthesized by polycondensation reaction of 1,2,4,5-tetraaminobenzene tetrahydrochloride with 2-sulfoterephthalic acid in poly(phosphoric acid). Isolated sPBI was measured in 30oC methanesulfonic acid for an intrinsic viscosity as high as 10.5 dL/g. sPBI polymer was then reacted with 1,3-propanesultone in dimethylsulfoxide containing sodium hydride for water-soluble rigid-rod polyelectrolyte, poly[1,7- dipropylsulfobenzo-[1,2-d:4,5-d¡¦]diimidazo-2,6-diyl-[2,(2-sulfo)-p-phenylene]], sPBI-PS(Na+). sPBI-PS(Na+) was further converted to sPBI-PS(Li+) with hydrochloride and followed with lithium hydroxide. Various analyses were applied to ascertain chemical structure, purities and thermal properties of synthesized monomers and polymers. sPBI-PS(Li+) aqueous solutions were doped individually with lithium salts of LiI, LiBF4, and LiCF3SO3 at concentrations up to 1.7¡Ñ10-5 wt./wt., which were cast into freestanding films of 10-25 £gm in thickness. Direct-current conductivity measured at room- temperature parallel to the film surface was as large as 9.74¡Ñ10-5 S/cm. The ionic nature of the conductivity was revealed by constant-voltage depletion measurements. X-ray scattering results suggested that the cast film was in-plane isotropic but out-of-the plane anisotropic with the rigid-rod backbone lying in the plane of the film.

The number of newly developed chemical entities exhibiting poor water solubility has increased dramatically in recent years. In many cases this intrinsic property results in poor or erratic dissolution in biological fluids. Improving aqueous solubility of these compounds, even temporarily, can have a significant impact on in vivo performance. Single phase amorphous solid dispersions of a drug and polymer have emerged as a technique to not only increase the level of drug supersaturation but also maintain these levels for extended periods of time. Hot-melt extrusion (HME) has become the preferred processing technique to prepare systems such as these but has a number of limitations that prevent the successful formulation of many drug substances. Within this dissertation, the use of concentration enhancing polymers was investigated in parallel with a thorough evaluation of a novel fusion-based processing technique, KinetiSol® Dispersing (KSD), to prepare single phase amorphous solid dispersions that could not be successfully prepared by HME. Studies showed that the KSD technique is suitable for rendering thermally labile and high melting point drug substances amorphous through a combination of frictional and shearing energy. Compounds such as these were shown to degrade during HME processing due to relatively long residence times and low shear forces. Similarly, the KSD process was shown to successfully process solid dispersion compositions containing a high viscosity polymer with significantly lower levels of polymer degradation than obtained by HME processing. In the final study, KSD processing was used to prepare solid dispersions containing the hydrophilic polymer Soluplus[superscript TM] and methods were evaluated to formulate a tablet with rapid tablet disintegration characteristics, a requirement for sufficient dissolution enhancement. Combined, the studies demonstrated the effectiveness of combining proper polymer selection and formulation approaches with a suitable processing technique to form solid dispersion systems that provide rapid and extended durations of supersaturation. / text

Cancer remains a global pandemic and is rapidly overtaking other diseases as the no.1 killer in developing nations. Photodynamic therapy (PDT) has been advanced as a minimally invasive cancer therapy. In addition, the emergence of harmful microbes with increasing resistance to drugs has prompted the employment of photodynamic antimicrobial chemotherapy (PACT) as a promising alternative to combat antibiotic resistance. In PDT and PACT, a photosensitizer (dye/drug) upon activation by light transfers energy to molecular oxygen producing singlet oxygen which kills cells. There is increased attention and research into more selective and non-aggregated photosensitizers that will better PDT in treating cancer. This research work is focused on design and synthesis of non-aggregated asymmetric phthalocyanines (dyes) tagged with mitochondrial targeting vehicles to maximize selectivity and photo-killing of tumor cells. Chapter 1 presents a brief review of the current status of PDT and treatment of cancer. The three components of PDT namely, light, oxygen and the photosensitizer, are briefly discussed giving a concise overview of the development of each of them in bettering PDT as an alternative to cancer therapy. Chapter 2 outlines the design, synthesis and characterization of two non-aggregated symmetric ZnPc isomers that have improved water solubility due to incorporation of triethylene glycol groups. The extension of the max absorption to near-IR via non-peripheral substitution on the Pc macrocycle is reported, while comparing the photophysical characteristics of both isomers. Chapter 3 details the improved selectivity of photosensitizers by conjugating ZnPcs to rhodamine B, a delocalized lipophilic cation, which targets the mitochondria of the cell. This conjugation achieved 70% more cell death suggesting that incorporation of rhodamine improved cellular uptake and localization of the photosensitizers which is crucial. Chapters 4 and 5 cover the design, synthesis, characterization, and photodynamic therapy evaluation of ZnPc and phosphorous phthalocyanines. Introduction of phosphorous as an electron deficient central atom promoted a 42 nm bathochromic shift relative to the corresponding ZnPc isomer. Additionally, the effect of peripheral and non-peripheral substitution on phototoxicity of these new compounds is studied and reported. Chapter 5 also gives concluding remarks, and future directions of this work.

The focus of this dissertation is the use of aluminum Schiff base compounds, Salen(tBu)AlBr (SAB), in the dealkylation and detection of organophosphates (OPs). Three SAB compounds, Salen(tBu)AlBr (1), Salpen(tBu)AlBr (2), and Salophen(tBu)AlBr (3) were used to dealkylate a variety of trialkyl OPs. These reactions lead to unique organic-soluble aluminum phosphate compounds containing six-coordinate aluminum. Examples include [salen(tBu)AlOP(O)(OCH3)2]n (4), [salen(tBu)AlOP(O)(OCH2CH3)2]n (5), [salen(tBu)AlOP(O)(OPh)2]n (6), [Salophen(tBu)AlOP(O)(OCH3)2 (7), Salpen(tBu)AlOOP(O)(OiPr)2 (8). These compounds are unique examples of polymeric (4, 5, 6 and 7) and dimeric compounds (8) with salenAl units connected by phosphate linkages. The compounds do not decompose in neutral water. This is an advantage in the use of SABs for the deactivation of phosphate esters such as nerve agents. Water-soluble and stable group 13 salen complexes, Salen(SO3Na)MNO3 (M =Al (19), Ga (22)), Salpen(SO3Na)MNO3 (M = Al (20), Ga (23)), and Salophen(SO3Na)M(NO3) (M = Al (21), Ga (24)) were synthesized by using water-soluble Salen(SO3Na) ligand. All the compounds were characterized by various analytical techniques: 1H and 13C NMR, IR, and melting point. One SAB was used to detect the nerve agents (NA). Salen(tBu)Al(Ac), prepared in situ from Salen(tBu)AlBr and NaAc, forms Lewis acid-base adducts with the NAs, GB (sarin) and GD (soman), and the VX hydrolysis product, EMPA, in aqueous solution. The [Salen(tBu)Al(NA)]+ compound is sufficiently stable to allow the identification of the NA with ESI-MS. Molecular ion peak was detected for every compound with little or no fragmentation. The distinctive MS signatures for [Salen(tBu)Al(NA)]+ compounds provide a new technique for identifying NAs in aqueous solution.

This study covers grafting of Acrylic Acid (AA) and Methacrylic Acid (MAA) on Ultrahigh Molecular Weight Polyethylene (UHMWPE) thin films by surface grafting and xylene-swollen grafting methods with Co-60 &amp / #947 / -ray in air. Also characterizations of pure, irradiated and grafted films were made by applying gravimetric, spectroscopic, thermal and mechanic tests. The thin films of UHMWPE were prepared by using compression molding. AA and MAA grafting on thin UHMWPE films were carried out by surface grafting and xylene-swollen grafting methods. During grafting processes, homopolymerization of monomers was avoided by using Fe2+ and Cu2+ ions. Grafting degree of AA and MAA were calculated for the samples irradiated at different doses. To verify grafting of AA and MAA on UHMWPE films, FTIR spectra of grafted films were used. Metal-uptake capacity is important property of grafted polyethylene for environmental applications. Thus, we examined metal-uptake capacities of AA and MAA grafted films for Fe(III) and Ni (II) and it was found that AA and MAA grafted UHMWPE films showed good affinity towards Fe(III) and Ni(II) metals. Thermal behavior of films were examined by DSC analysis. First run and second run DSC thermograms showed the thermal stability of films under heat. Mechanical properties of UHMWPE decrease with irradiation and grafting. However stress at break values of xylene-swollen grafted samples tend to increase with irradiation dose. In conclusion, water soluble monomers were successfully grafted on UHMWPE and these AA and MAA grafted UHMWPE films can be used in biomedical, environmental applications and other related areas.

Since the discovery of the drag reduction effects of even small amount of macromolecules in solutions in turbulent pipe flows, there have been many experimental and theoretical studies in order to understand mechanisms behind this phenomenon. Theories have been proposed based on the observations on the change in the characteristics of the turbulent flow near the pipe wall where friction of the momentum transfer between the flow and the conduit takes place. In this study drag reduction in fully developed turbulent pipe flow with four concentrations (200 to 500 wppm) of low molecular weight Sodium Carboxymethylcellulose (CMC) in aqueous solutions was investigated experimentally. Drag reduction was determined by pressure drop measurements. In order to observe the impact of the presence of CMC on the flow, Ultrasound Doppler Velocimetry (UDV) was employed to monitor the instantaneous velocity distributions. UDV is a non-invasive technique allowing one to obtain quick velocity profiles. Experimental measurements were used to calculate Fanning friction factor and radial distributions of the axial time-averaged velocity, velocity fluctuation (turbulent intensity) and eddy viscosity. The drag reduction level was determined through the Fanning friction factor versus Reynolds number data. Velocity data could be obtained as close as 3 mm to the wall by UDV. Two impacts of increasing CMC concentration on the flow field, hence pressure drop, were observed. The first effect was the decrease of the mean velocity gradient especially near the wall with increasing polymer amount which in turn gave rise to lower friction factor or pressure drop. In addition smaller eddy viscosities were obtained in the flow. The second impact of the polymer addition was on the velocity fluctuation or turbulent intensity variation along the radial distribution. An increasing trend in turbulence intensity in the turbulent core with polymer addition was observed. This was in agreement with the earlier studies in which similar turbulence behavior was observed in addition to the suppression of the turbulent intensities near the wall

Thesis (Ph. D.)--University of Missouri-Columbia, 1997. / Typescript. Vita. Includes bibliographical references (leaves 240-150). Also available on the Internet.