Oxidative stress is known to contribute to many forms of heart disease. Oxidants such as H₂O₂ can cause hypertrophy of cardiomyocytes (CMCs). Heart fibroblasts (HFs) also contribute to oxidant-induced heart disease by disordering the extracellular matrix and causing fibrosis. Since both of these cells encounter the same stressors in vivo, we examined the signaling pathways involved in responding to oxidative stress in both cell types. We have established the EGF Receptor, Src and matrix metalloproteinases (MMPs) as key regulators of oxidant-mediated phosphorylation of the MAPKs ERK1/2 and JNKs but not p38 in CMCs and HFs. We used oligonucleotide microarrays to examine the differences in global gene expression after H₂O₂ treatment in CMCs and HFs. Twenty-four hours after treatment, significant numbers of upregulated genes could be classified as being related to antioxidant or detoxification responses in both cell types. This trend lead us to examine the role of activation of promoters containing the Antioxidant Response Element (ARE) in the reaction of CMCs to H₂O₂. We have shown that H₂O₂ activates the ARE in CMCs in a manner that is dependant on the transcription factor Nf-E2 related factor 2 (Nrf2). ARE activation by H₂O₂ seems to induce cytoprotection. CMCs pretreated with H₂O₂ showed significantly less activation of caspase-3 when exposed to another oxidant, Doxorubicin. Overexpression of Nrf2 mediates this cytoprotection, possibly by protecting the cells from caspase-independent cell death. Although ARE-dependant genes were upregulated in the presence of excess Nrf2, two contractile proteins were repressed, suggesting that Nrf2 overexpression may have unknown side-effects in CMCs. We also studied the activation mechanism of Nrf2 in CMCs. Nrf2 protein levels increased after 10 min of exposure to 100 μM H₂O₂ and peaked at about 1 hr. Pharmacological and genetic inhibition of the PI3-Kinase pathway blocked AREluciferase activity in these cells. The PI3-Kinase inhibitor LY294002 also blocked Nrf2 protein accumulation, but not nuclear translocation. Here I present evidence that Nrf2 accumulation after H₂O₂ exposure is due to PI3-Kinase-mediated translational regulation. Since phosphorylation of translation initiation factors eIF4E and eIF2alpha are both inhibited by LY294002, Nrf2 translation initiation may be through non-5’ cap-mediated means.

This thesis reports the outcome of a simulation study that examines the feasibility of using hydrogen peroxide as an alternative oxidant in the autothermal reforming (ATR) of diesel. The primary objective is to compare hydrogen peroxide's performance against conventional oxidants in reforming, focusing on product distribution and three pivotal process properties: diesel conversion, hydrogen production, and ethylene generation. The study further investigates the influence of the heat of decomposition on the performance and reaction routes of different oxidants. Additionally, a comparative analysis is conducted on the reforming performance in different reformer configurations, specifically contrasting a combined-reformer-configuration with a catalytic-reformer configuration. The ANSYS Chemkin-Pro is utilized to understand the potential benefits and challenges of the proposed approached. A reduced chemical mechanism of N-heptane/Toluene reforming as a surrogate for diesel, combined with a detailed surface reaction mechanism of propene on a three-way Pt/Rh catalyst are used in this study. It is found that the use of hydrogen peroxide as an oxidant demonstrated a complete fuel conversion and 183% higher hydrogen yield when compared with conventional oxidants. It also led to a 12% lower generation of ethylene, a precursor for coke formation. The catalytic-reformer configuration showed superior performance over the combined-reformer-configuration in terms of hydrogen yield. The insights from this study offer valuable perspectives on the feasibility and efficiency of using hydrogen peroxide as an alternative oxidant in the ATR of diesel, paving the way for potential advancements in the field.

<p> Introduction: 17β-estradiol (E2) has proposed anti-oxidant and membrane stabilizing properties that may attenuate exercise-induced damage, inflammation and alter gene expression. The purpose of this thesis was to determine if acute E2 supplementation would affect the oxidative stress, membrane damage, inflammation and global mRNA expression induced by eccentric exercise. Methods: 18 healthy young males were randomly assigned to 8 days of placebo (CON) or E2 (EXP) supplementation. Blood and muscle samples were collected at baseline (BL), following supplementation (PS), +3 hours (3H) and +48 hours (48H) after 150 single-leg eccentric contractions. Blood samples were analyzed for hormone concentration, creatine kinase (CK) activity and total antioxidant capacity (T AC). Inflammation was quantified by neutrophil and macrophage infiltration. Genes selected a priori for oxidative stress defense, membrane homeostasis and growth were analyzed with real-time RT-PCR. High density oligonucleotide based microarrays were screened for novel differences in mRNA expression. Results: A primary finding was that increased serum E2 did not affect anti-oxidant capacity, creatine kinase efflux or mRNA content of genes related to oxidative stress defence and membrane homeostasis. E2 did attenuate neutrophil infiltration into muscle but did not affect macrophage density. Microarray analysis revealed that exercise induced differential expression of 611 genes at 3H and confirmed that E2 did not affect mRNA content. Genes were manually clustered into biological categories and from this dataset the signaling pathways for RhoA and NF AT were identified as transcriptionally active. Both pathways regulate hypertrophic signaling through the AP-1 transcription factor complex. Conclusions and significance: A major contribution ofthis thesis is that E2 may affect exercise induced inflammation through mechanisms that that do not affect oxidative stress or membrane stability. Additionally, the transcriptional activation ofSTARS/RhoA/APl and NFAT/APl indicates that both are important for early repair and remodelling signaling after a single bout of unaccustomed eccentric exercise. </p> / Thesis / Doctor of Philosophy (PhD)

Faculty of Sciences School of Pharmacy and Pharmacology 0000073k moollaaneesa@yahoo.com / As part of an investigation of the biological activities of South African plants and due to their extensive traditional use and lack of scientific evidence, a phytochemical and pharmacological investigation was performed on 17 indigenous Agathosma species (19 samples). The chemical composition of the essential oils was determined using gas chromatography coupled to mass spectroscopy (GC-MS). Analysis resulted in the identification of 333 compounds. To evaluate the chemical similarities and differences, cluster analysis was used to assess the essential oil composition of the samples. The results showed qualitative and quantitative differences amongst the taxa. The essential oils of Agathosma hirsuta and A. zwartbergense are particularly rich in citronellal, hence they are tightly clustered in the dendrogram obtained from the cluster analysis. Linalool, myrcene and limonene are the major constituents of both A. capensis (Gamka) and A. capensis (Besemfontein). Qualitative and quantitative differences are noted in the chemical compositions of the leaf oils of Agathosma capensis (Gamka) and A. capensis (Besemfontein). Agathosma arida and A. lanata are united in a single cluster due to the compounds β-pinene, linalool and spathulenol being major components in both species. The presence of 1,8-cineole in large quantities in both Agathosma namaquensis (23.5%) and A. ovalifolia (9.7%), unites them in a single cluster. A wide chemical variability for the essential oils of indigenous Agathosma species has been demonstrated. There was considerable variation in the percentage oil yield of the essential oils. Agathosma hirsuta produced the highest yield (1.15%) whilst A. ovalifolia produced the lowest yield (0.16%). vi Previous studies have revealed that the coumarin and flavonoid components of Agathosma species are responsible for their biological activities. High performance liquid chromatography (HPLC) was used to document the non-volatile composition of Agathosma species and to establish if phenolic patterns were present amongst the species. All species were found to be rich in flavonoids (i.e. flavones and flavonols). Many of the compounds detected were common to most of the species. A pure coumarin, puberulin, was identified in the diethyl ether extract of Agathosma ovata (round-leaf) and detected in the dichloromethane and methanol (1:1) extract of A. namaquensis. Agathosma species have been used traditionally to treat a wide variety of infections. They has been used as a cough remedy, for the treatment of colds and flu, kidney and urinary tract infections, for the treatment of cholera and other stomach ailments. Based on the extensive use and lack of scientific evidence, a study was embarked upon to determine its bioactivity. Using the disc diffusion assay as a preliminary screening and thereafter the minimum inhibitory concentration (MIC) assay, the antimicrobial activity of the essential oils and non-volatile compounds was assessed on two Gram-positive bacteria, Staphylococcus aureus and Bacillus cereus, one Gram-negative bacterium, Klebsiella pneumoniae, and one yeast, Candida albicans. All of the extracts proved to be active against the four pathogens tested with the exception of Agathosma bathii which showed poor activity against Klebsiella pneumoniae (MIC value of 32mg/ml). The extracts exhibited stronger activity against the pathogens as compared to the essential oils. Both the essential oils and extracts exhibited higher activity towards the Gram-positive bacteria than the Gram-negative bacterium, with the extract of Agathosma ovata (round-leaf) displaying the greatest vii activity against Staphylococcus aureus (MIC value of 0.156mg/ml) and Bacillus cereus (MIC value of 0.125mg/ml). The extract of Agathosma parva displayed the greatest activity against Candida albicans and Klebsiella pneumoniae (MIC value of 1.5mg/ml). Amongst the essential oils, Agathosma pungens proved to be the most active against the Gram-positive pathogen, Bacillus cereus (MIC value of 3mg/ml). Agathosma collina was the most active against Candida albicans (MIC value of 3mg/ml) whilst A. zwartbergense proved to be the least active against most of the tested pathogens. The antimicrobial activity of the essential oils may be ascribed to oxygenated constituents, such as 1,8-cineole, linalool and carvacrol. The activity of the extracts may be ascribed to constituents such as flavonoids, coumarins and alkaloids. Due to the availability and accessibility of Agathosma ovata, a seasonal variation study was performed on the chemical composition of the essential oils and how this may impact on the antimicrobial activity. Furthermore, this species has recently been earmarked for commercial development by the flavour and fragrance industry and information on variability is required to establish the harvesting protocol. Ten samples were harvested in total. There was a substantial variation in the oil yield throughout the year, ranging from 0.23% in early Spring to 0.85% in late Autumn. A higher yield was observed during the flowering season as compared to the non-flowering season. Oil yields were low during Summer (0.44%-0.48%) which may have been due to the low oil content in stems and higher proportion of stems after flowering. The proportion of oil-rich green leaves also decreased markedly, hence affecting the yield. Overall the yields were dependant on the season harvested and proportion of plant parts distilled. viii The chemical composition of the essential oils was determined using GC-MS and resulted in the identification of 145 compounds in 10 of the samples. All samples contained a large number of common monoterpenes and had very similar compositions, with minor quantitative variation. Some components common to all samples include: sabinene, p-cymene, β-pinene, α-pinene, α-thujene, myrcene, limonene, linalool and terpinen-4-ol. Sabinene was found to be the most dominant component in all samples, ranging between 25.6% and 44.4%. Myrcene levels dropped sharply between the beginning of Spring and end of Summer, from 14.9% to 1.0%. β-pinene followed a similar trend, peaking during Spring and decreasing during the Summer months. The lowest levels of linalool (4.3%), myrcene (1.0%), β-pinene (3.9%), limonene (1.9%) and sabinene (25.6%), occurred during the Summer months when the temperatures were high. There was a Springtime increase in the levels of β- pinene, terpinen-4-ol, linalool, sabinene, limonene and p-cymene in the non-flowering Agathosma ovata. These changes may have been due to the higher proportion of young leaves during Spring, which may have oil compositions slightly different to those of mature leaves. A rare thiol derivative (tr) that could not be identified was detected in the March sample. Many of the changes were associated with flowering and the results obtained reveal that the chemical composition of the essential oil of Agathosma ovata is subject to seasonal variation. Using the MIC assay, the antimicrobial activity of the essential oils was assessed on two Gram-positive bacteria, Staphylococcus aureus and Bacillus cereus, one Gramnegative bacterium, Klebsiella pneumoniae, and one yeast, Candida albicans. The study demonstrated differences in the potency of antimicrobial activity of the essential oils distilled each month. The Winter samples were more active against Bacillus cereus, Staphylococcus aureus and Klebsiella pneumoniae. Activity in mid Spring ix was greater against Staphylococcus aureus (MIC value of 3mg/ml) and Klebsiella pneumoniae (MIC value of 3mg/ml), whilst activity decreased in Summer. There was a correlation between the concentrations of the active compounds each month and the oils antimicrobial activity. The results reveal that the antimicrobial activity of the essential oil of Agathosma ovata may not depend on the level of one component but rather the ratio of several components. ‘Buchu’ has been used traditionally as a general tonic and medicine. Tonics generally have a high anti-oxidant content in order to promote the overall well-being of the user. The anti-oxidant properties of the essential oils and non-volatile compounds was investigated using the 2, 2-diphenyl-1-picrylhydrazyl (DPPH) and 2, 2'-azinobis(3- ethylbenzothiazoline-6-sulfonic acid) (ABTS) assays. Only the non-volatile compounds exhibited activity. Their activities may be ascribed to the flavonoid components. Most of the species portrayed moderate to poor activity in the DPPH assay with the exception of Agathosma capensis (Gamka) (IC50 value of 24.08 + 4.42μg/ml) and A. pubigera (IC50 value of 35.61 + 0.86μg/ml) which were two of the most active species, although their activities were inferior when compared to vitamin C. The results from the ABTS assay differed from that of the DPPH assay. All extracts showed greater activity in this assay with Agathosma namaquensis (IC50 value of 15.66 ± 4.57μg/ml) and A. capensis (Besemfontein) (IC50 value of 19.84 ± 0.09μg/ml) being the most active species. This may be due to the ABTS assay having an additional reaction system. ‘Buchu’ has been used traditionally as an antipyretic, topically for the treatment of burns and wounds and for the relief of rheumatism, gout and bruises. The antix inflammatory activity of the essential oils and non-volatile compounds was assessed using the 5-lipoxygenase (LOX) assay. Only the essential oils exhibited activity. All proved to be active with the exception of Agathosma stipitata which was UV active and caused interference. This was due to its major compounds neral (39.9%) and geranial (10.1%) which absorbed strongly at 234 nm and hence rendered its spectrophotometric measurement impossible. The essential oil of Agathosma collina displayed the most promising activity (IC50 value of 25.98 ± 1.83μg/ml). It is well known that many herbal medicines can have adverse effects, in which case it is necessary to evaluate the benefit-risk profile. The toxic effects of Agathosma species have been poorly studied and no information is available in this regard. Hence the toxicity profile of the non-volatile compounds and essential oils was assessed on transformed human kidney epithelium (Graham) cells using the microculture tetrazolium (MTT) cellular viability assay. The extracts of Agathosma lanata (IC50 value of 26.17 ± 9.58μg/ml) and A. ovata (round-leaf) (IC50 value of 25.20 ± 6.30μg/ml) proved to be the most toxic, whilst the extracts of Agathosma bathii, A. capensis (Besemfontein), A. betulina, A. crenulata and A. namaquensis did not prove to be toxic at the concentrations tested. Serial dilutions displayed different inhibitions of cell growth and the species proved to be toxic in a dose-dependant manner. The essential oils of all 19 species proved to be much more toxic (IC50 values < 0.0001μg/ml) than a plant-derived compound that is considered relatively safe, namely quinine (IC50 value of 136.06 ± 4.06μg/ml). The toxicities of the essential oils may be due to compounds like methyl chavicol, eugenol, methyl eugenol, pulegone and methyl salicylate whilst the toxicities of the extracts may be due to the alkaloid and coumarin components.

Os linfomas constituem um grupo de neoplasias que têm origem nas células linforreticulares e acomete tecidos linfóides primários, secundários como o baço e linfonodos e demais tecidos onde há presença de linfócitos circulantes, comumente descritos em cães, gatos e humanos. As síndromes paraneoplásicas são definidas como alterações sistêmicas não relacionadas com lesões metastáticas de forma direta ou indireta no hospedeiro. Dentre as alterações descritas como síndrome paraneoplásica, as alterações hematológicas constituem as mais freqüentes, apresentando destaque para os processos anêmicos. A anemia presente pode ser decorrente de alterações do metabolismo do ferro, perda sanguínea, distúrbios hemolíticos, infiltrado medular e hiperesplenismo. Atualmente tem se associado a redução da vida média das hemácias frente a presença do estresse oxidativo, que gera um desequilíbrio entre a excessiva produção de espécies reativas ao oxigênio e/ou a diminuição dos mecanismos de defesa antioxidante das hemácias. Esse processo pode ocasionar a peroxidação de lipídios da membrana eritrocitária, gerando hemólise e assim resultando em anemia e/ou exacerbando a mesma. Com o objetivo de avaliar a existência do estresse oxidativo e a presença de anemia assim como, a sua correlação com o estado redox, foram avaliadas as concentrações eritrocitárias de glutationa reduzida, glutationa redutase, glutationa peroxidase e superóxido redutase em 23 gatos sadios e 17 felinos com linfoma. Também foram determinadas as concentrações plasmáticas de malonaldeído como indicador da presença de peroxidação lipídica em ambos os grupos. Para avaliar o estado redox foi mensurada a concentração plasmática do estado antioxidante total para o grupo experimental e grupo controle. Não foram observadas diferenças significantes para as enzimas eritrocitárias glutationa redutase, glutationa peroxidade e superóxido dismutase, assim como para a mensuração plasmática de malonaldeído. Entretanto, foram observados valores significativamente menores (p=0,018) de glutationa reduzida nos felinos com linfoma quando comparados ao grupo controle. O mesmo pôde ser observado em relação à mensuração do estado antioxidante total (p=0,003). Os resultados obtidos indicam a presença de estresse oxidativo em felinos com linfoma, porém, não houve evidencias da relação entre a presença de estresse oxidativo e a presença de anemia. / Lymphomas are a group of cancers that originate in cells and lymphoreticular affects lymphoid tissues in primary, secondary as the spleen and lymph nodes and other tissues where there is presence of circulating lymphocytes, commonly described in dogs, cats and humans. Paraneoplastic syndromes are defined as systemic changes unrelated metastatic lesions either directly or indirectly in the host. Among the changes described as a paraneoplastic syndrome, hematological changes are the most frequent, with emphasis on the processes anemic. This anemia may be due to changes in iron metabolism, blood loss, hemolytic disorders, bone marrow infiltration and hypersplenism. Today has been associated with reduced average life span of red cells before the presence of oxidative stress, which creates an imbalance between excessive production of reactive oxygen species and / or decreased antioxidant defense mechanisms of red blood cells. This process can lead to lipid peroxidation of the membrane, causing hemolysis and thus resulting in anemia and / or exacerbating it. Aiming to evaluate the existence of oxidative stress and anemia as well as its correlation with redox state, were evaluated erythrocyte concentrations of reduced glutathione, glutathione reductase, glutathione peroxidase and superoxide reductase in 23 healthy cats and 17 cats with lymphoma. We also determined plasma concentrations of malondialdehyde as an indicator of the presence of lipid peroxidation in both groups. To assess the redox state was measured plasma concentration of total antioxidant status for the experimental group and control group. No significant differences were observed for enzymes erythrocyte glutathione reductase, glutathione peroxidase and superoxide dismutase, as well as for measurement of plasma malondialdehyde. However, observed values were significantly lower (p = 0.018) reduced glutathione in cats with lymphoma when compared to the control group. The same could be observed in relation to the measurement of total antioxidant status (p=0,003). The results indicate the presence of oxidative stress in cats with lymphoma, however, no evidence of the relationship between oxidative stress and anemia.

Type 2 diabetes mellitus affects over 100 million people worldwide. It is characterized by various metabolic abnormalities such as insulin resistance, aberrant insulin secretion, hyperglycaemia and a cluster of cardiovascular risk factors, including increased oxidative stress. It is associated with microvascular complications and increased potential of macrovascular disease. The aim of the studies described in this thesis was to test the hypothesis that oxidant stress contributes to an altered vascular function and impaired insulin regulation in a pre-diabetic animal model- the obese Zucker rats. The first objective was to develop new methods to measure endothelial function in animal disease models. Firstly, without autonomic control - the in situ perfused hindquarters, and secondly, with autonomic control - the in vivo Doppler ear blood flow. The obese Zucker rat was shown to have increased oxidative stress, as measured by plasma 8-epi-PGF2a,. It also had high insulin and glucose levels and impaired glucose disposal. Obese rats also had increased agonist-induced nitric oxide-dependent endothelial responses; these were further enhanced by insulin in a macrovascular preparation, but were impaired by insulin in a resistance vessel bed. Following dietary treatment with the antioxidants, the obese plasma insulin/glucose ratio was improved. However, vitamin E blunted the enhanced endothelial-dependent vasodilator responses, and decreased plasma levels of 8-epi-PGF2a. In contrast, pro-oxidant treatment with hydroquinone and buthionine-sulphoximine impaired the plasma insulin/glucose ratio, abolished endothelial hyperactivity but increased plasma 8-epi-PGF2a levels. Interestingly, fructose protected against pro-oxidant-induced increases in plasma 8-epi-PGF2a levels and further increases in glucose-induced plasma insulin. In summary the redox status in obese Zucker rats was modified with antioxidant and prooxidant treatment. This resulted in compensatory changes in glucose disposal and endothelial function. Impaired endothelial function may initiate "damage" especially in those individuals susceptible to syndrome X, leading to insulin insensitivity and vascular dysfunction in type 2 diabetes.

2,5-diaminoimidazolone (Iz) is an important product of a 4-electron oxidation of guanine. The present research focuses on the mechanisms of formation of Iz via pathways initiated by guanine oxidation by one-electron oxidants (OEOs) generated by X-ray radiolysis in aqueous solutions. The kinetics of formation and yields of Iz in reactions of native highly polymerized DNA with different OEOs have been compared using an HPLC-based quantitative analysis of low-molecular products generated from the reaction of DNA-bound Iz with primary amines. Mechanisms of Iz formation in DNA have been investigated including oxygen and superoxide dependence as well as the hypothesis that 8-oxo-G, another product of guanine oxidation, is not a major precursor to Iz. Results indicate Iz is produced in significant quantities in DNA from guanine oxidation and the efficiency of its formation correlates with the reduction potential and selectivity of a given OEO.

We hypothesized that the interaction between tumor necrosis factor alpha(TNF)/nuclear factor-kappaB (NFkB) via activation of IKK may amplify one anotherresulting in the evolution of vascular disease and insulin resistance associated withdiabetes. The interaction between TNFa and monocyte chemoattractant protein-1 (MCP-1) may contribute to the evolution of vascular inflammation and endothelial dysfunctionin coronary arterioles in type 2 diabetes. To test this hypothesis, endothelium-dependent(ACh) and –independent (SNP) vasodilation of isolated, pressurized coronary arterioles(40-100 μm) from mLeprdb (heterozygote, normal), Leprdb (homozygote, diabetic) andLeprdb mice null for TNF (dbTNF-/dbTNF-) were examined. Although dilation of vesselsto SNP was not different between Leprdb and mLeprdb mice, dilation to ACh was reducedin Leprdb mice. The NFkB antagonist, MG-132, IKK inhibitor, sodium salicylate(NaSal), or Anti-MCP-1 partially restored endothelium-dependent coronary arteriolardilation in Leprdb mice. Protein expression of IKK and IKK were higher in Leprdb thanin mLeprdb mice. The expression of IKK, but not the expression of IKK was increasedin dbTNF-/dbTNF- mice. Leprdb mice showed increased insulin resistance, but NaSal improved insulin sensitivity. Protein expression of TNFa, NFkB, phosphorylation ofIKK and JNK were greater in Leprdb mice, but NaSal attenuated protein expression ofthem in Leprdb mice. The ratio of phosphorylated IRS-1 at Ser307 (pIRS-1)/IRS-1protein expression was elevated in Leprdb mice; both NaSal and JNK inhibitor SP600125reduced pIRS-1/IRS-1 in Leprdb mice. MG-132 or neutralization of TNF reducedsuperoxide production in Leprdb mice. Anti-MCP-1 attenuated superoxide productionand protein expression of nitrotyrosine (N-Tyr), which is an indicator of peroxynitriteproduction, in isolated coronary arterioles of Leprdb mice. Immunostaining resultsshowed that expression of MCP-1 and vascular cellular adhesion molecule-1 (VCAM) isco-localized with endothelial cells and macrophages. Anti-TNFa or anti-MCP-1markedly reduced macrophage infiltration and the number of MCP-1 positive cells.Neutralization of TNFa or anti-MCP-1 reduced the expression of adhesion molecules. Inconclusion, our results indicate that the interaction between NFkB and TNFa signalinginduces activation of IKKb. In addition, TNFa and TNFa-related signaling, includingthe expression of MCP-1 and adhesion molecules, further exacerbates oxidative stressleading to endothelial dysfunction in type 2 diabetes.

As the minimum feature size in complementary metal-oxide-semiconductor (CMOS) devices shrinks, the leakage current through the gate insulator (silicon oxide) will increase sufficiently to impair device operation. A high dielectric constant (k) insulator is needed as a replacement for silicon oxide in order to reduce this leakage. Hafnium-based materials are among the more promising candidates for the gate insulator, however, it is hampered by material quality and thus has been slow to be introduced into high volume integrated circuit production. Hafnium oxynitride films are deposited by Metalorganic Chemical Vapor Deposition (MOCVD) and downstream microwave Plasma Enhanced Chemical Vapor Deposition (PECVD) employing different oxidants including O2, N2O, O2 plasma, N2O plasma, N2O/N2 plasma, and O2/He plasma in the current research. The effects of oxidants on deposition kinetics, morphology, composition, bonding structure, electrical properties and thermal stability of the resultant films each are investigated. The possible chemical/physical causes of these observations are developed and some mechanisms are proposed to explain the experimental results. Oxygen radicals, which are known of present in oxidizing environments are determined to play an essential role in defining both structures and the resultant electronic properties of deposited hafnium oxynitride films. This systematic investigation of oxidant effects on CVD grown hafnium oxide/oxynitride layers, in the absence of post-deposition annealing, provides new understanding to this area with potential importance to the integrated circuit industry.

We hypothesized that the interaction between tumor necrosis factor alpha(TNF)/nuclear factor-kappaB (NFkB) via activation of IKK may amplify one anotherresulting in the evolution of vascular disease and insulin resistance associated withdiabetes. The interaction between TNFa and monocyte chemoattractant protein-1 (MCP-1) may contribute to the evolution of vascular inflammation and endothelial dysfunctionin coronary arterioles in type 2 diabetes. To test this hypothesis, endothelium-dependent(ACh) and –independent (SNP) vasodilation of isolated, pressurized coronary arterioles(40-100 μm) from mLeprdb (heterozygote, normal), Leprdb (homozygote, diabetic) andLeprdb mice null for TNF (dbTNF-/dbTNF-) were examined. Although dilation of vesselsto SNP was not different between Leprdb and mLeprdb mice, dilation to ACh was reducedin Leprdb mice. The NFkB antagonist, MG-132, IKK inhibitor, sodium salicylate(NaSal), or Anti-MCP-1 partially restored endothelium-dependent coronary arteriolardilation in Leprdb mice. Protein expression of IKK and IKK were higher in Leprdb thanin mLeprdb mice. The expression of IKK, but not the expression of IKK was increasedin dbTNF-/dbTNF- mice. Leprdb mice showed increased insulin resistance, but NaSal improved insulin sensitivity. Protein expression of TNFa, NFkB, phosphorylation ofIKK and JNK were greater in Leprdb mice, but NaSal attenuated protein expression ofthem in Leprdb mice. The ratio of phosphorylated IRS-1 at Ser307 (pIRS-1)/IRS-1protein expression was elevated in Leprdb mice; both NaSal and JNK inhibitor SP600125reduced pIRS-1/IRS-1 in Leprdb mice. MG-132 or neutralization of TNF reducedsuperoxide production in Leprdb mice. Anti-MCP-1 attenuated superoxide productionand protein expression of nitrotyrosine (N-Tyr), which is an indicator of peroxynitriteproduction, in isolated coronary arterioles of Leprdb mice. Immunostaining resultsshowed that expression of MCP-1 and vascular cellular adhesion molecule-1 (VCAM) isco-localized with endothelial cells and macrophages. Anti-TNFa or anti-MCP-1markedly reduced macrophage infiltration and the number of MCP-1 positive cells.Neutralization of TNFa or anti-MCP-1 reduced the expression of adhesion molecules. Inconclusion, our results indicate that the interaction between NFkB and TNFa signalinginduces activation of IKKb. In addition, TNFa and TNFa-related signaling, includingthe expression of MCP-1 and adhesion molecules, further exacerbates oxidative stressleading to endothelial dysfunction in type 2 diabetes.