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Full-Text Articles in Physical Sciences and Mathematics

Nos-Based Biopolymers: Towards Novel Thromboresistant No-Release Materials, Charbel Abou Diwan Jan 2009

Nos-Based Biopolymers: Towards Novel Thromboresistant No-Release Materials, Charbel Abou Diwan

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Nitric Oxide releasing biopolymers have the potential to prolong vascular graft and stent potency without adverse systemic vasodilation. It was reported in literature that eNOS-overexpressing endothelial cell seeding of synthetic small diameter vascular grafts decreased human platelet aggregation by 46 and bovine aortic smooth muscle cell proliferation by 67.2 in vitro. We hypothesized that incorporating the enzyme nitric oxide synthase (NOS) in biocompatible polymeric matrix will provide a source of NO that utilizes endogenous compounds to maintain an unlimited supply of NO. To test this hypothesis, we have incorporated the enzyme nitric oxide synthase into a polyethyleneimine film using a …


Cofactor Control Of A Vital Enzymatic Reaction;The Effect Of Factor Va On Thrombin Formation During Blood Coagulation, Jamila Hirbawi Jan 2009

Cofactor Control Of A Vital Enzymatic Reaction;The Effect Of Factor Va On Thrombin Formation During Blood Coagulation, Jamila Hirbawi

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The LONG-TERM goal of our research is to study and analyze the structure and function of the factor V molecule in order to understand its regulatory effects on the natural process of hemostasis and its role in the life-threatening development of deep venous thrombosis. The SHORT-TERM goal of our research is to identify the amino acid residue(s) of factor V that interact with prothrombin during the assembly and function of the prothrombinase complex in order to fully understand its particular role in maintaining the integrity of the blood coagulation cascade. The final goal of the coagulation cascade is the formation …


Hemoprotein-Mediated Activation Of Nitroalkanes, Ling Li Jan 2009

Hemoprotein-Mediated Activation Of Nitroalkanes, Ling Li

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Chemicals and drugs are known to be metabolized mostly by Cytochrome P450 xenobiotic metabolizing enzymes. However, the detailed mechanism of nitro-compounds metabolism is still unclear. The activation of nitro-xenobiotics by heme-P450 enzymes is a potential explanation for the origin of nitro-compound carcinogenesis. Investigating the interaction of simple nitro-compounds with redox activity of heme enzymes is therefore critical to explore the mechanism and products of activation. In this study, multiple analytical methods and instrumentations are employed and graphic and simulation software such as Origin┬« and Digisim┬« are utilized to quantitatively derive parameters from experimental raw data. This study shows that myoglobin, …


Structural Investigation Of The Complex Of Filamin A Repeat 21 With Integrin Αiib And Β3 Cytoplasmic Tails – A Potential “Transmission” To Regulate Cell Migration, Jianmin Liu Jan 2009

Structural Investigation Of The Complex Of Filamin A Repeat 21 With Integrin Αiib And Β3 Cytoplasmic Tails – A Potential “Transmission” To Regulate Cell Migration, Jianmin Liu

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Cell functions in multi-cellular organisms are strongly depend on the dynamic cooperation between cell adhesion and cytoskeleton reorganization. Integrins, the major cell adhesion receptors, bind to extracellular matrix (ECM) and soluble ligands on the cell surface and link to the actin cytoskeleton inside the cell membrane. In this manner, integrins integrate cell adhesion and cytoskeleton reorganization by acting as a mechanical force transducer and a biochemical signaling hub (Zamir and Geiger 2001). Consequently, integrins are vital for development, immune responses, leukocyte traffic and hemostasis, and a variety of other cellular and physiological processes. Integrins are also are the focal point …


Hemeproteins Bathed In Ionic Liquids;Examining The Role Of Water And Protons In Redox Behavior And Catalytic Function, John Joseph Moran Jan 2009

Hemeproteins Bathed In Ionic Liquids;Examining The Role Of Water And Protons In Redox Behavior And Catalytic Function, John Joseph Moran

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We investigate the changing behaviors of myoglobin and nitric oxide synthase (NOS) in the near-absence of bulk water and/or protons by using ionic liquid butyl methyl imidazolium tetrafluoroborate as a non-aqueous milieu. Through direct charge transfer and metalloprotein-mediated catalytic reduction of oxygen and nitric oxide, we shed light on diverging aspects on how the two hemeproteins face the scarcity of water and/or protons in bulk. Isotopic effect investigations using D2O further elucidates kinetic aspects of proton transfer. Finally, in the case of NOS oxygenase, pterin cofactor binding and NOS-mediated catalytic oxidation of L-arginine in ionic liquids interrogates proton and water …


Development Of Quantitative Bioanalytical Methods For The Measurement Of Pharmaceutical Compounds Via Hplc-Uv And Hplc-Ms/Ms, Melissa A. Mcculloch Jan 2009

Development Of Quantitative Bioanalytical Methods For The Measurement Of Pharmaceutical Compounds Via Hplc-Uv And Hplc-Ms/Ms, Melissa A. Mcculloch

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Research in pharmaceutical treatments for illnesses and disease processes has rapidly grown in the past decade. The field is fueled by advances in our understanding of the molecular mechanics of the human body, coupled with the development of sophisticated scientific instruments which can efficiently generate massive amounts of important data. This has led to an ever-growing need for the development of quantitative bioanalytical methods to measure pharmaceutical compounds. In this work, the theory behind the analytical processes and instruments that make these investigations possible is discussed. Further, the development of two high performance liquid chromatographic (HPLC) methods with both ultra …


Fabricating New Miniaturized Biosensors For The Detection Of Dna Damage And Dna Mismatches, N. Indika Perera Jan 2009

Fabricating New Miniaturized Biosensors For The Detection Of Dna Damage And Dna Mismatches, N. Indika Perera

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A large number of genetic diseases and genetic disorders are simply caused by base alterations in the genome. Therefore, developing efficient and cost effective techniques for routine detection of these alterations is of great importance. Different methods involving gel electrophoresis and Polymerase Chain Reaction have been widely employed, but majority of these methods are costly, time consuming, and lack throughput, creating a fundamental gap between the current state-of-the-art and desired characteristics of low-cost, high-speed, simplicity, versatility, and potential for miniaturization. In this study, we attempt to bridge this gap by developing new sensing platforms to detect DNA base mismatches and …


New Generation Of Electrochemical Sensors For Nitric Oxide;Ruthenium/Carbon-Based Nanostructures And Colloids As Electrocatalytic Platforms, W. Pubudu M. Peiris Jan 2009

New Generation Of Electrochemical Sensors For Nitric Oxide;Ruthenium/Carbon-Based Nanostructures And Colloids As Electrocatalytic Platforms, W. Pubudu M. Peiris

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Nitric oxide (NO) is an important intercellular messenger that acts in many tissues to regulate a diverse range of physiological and pathological processes. The physiologically implications of NO function are far from being completely understood. The multifaceted reactivity of NO prompted the need for accurate determination of the concentration of this molecule. However, it is difficult to detect nitric oxide, particularly in biological media and near live cells due to its short half-life, a result of its reactivity and the low levels of NO produced in vivo. As a result, the accurate and reliable detection of NO under varying experimental …


Nitric Oxide Synthase In Confined Environments;Detection And Quantification Of Nitric Oxide Released From Cells And Modified Liposomes Using A Sensitive Metal Catalyst-Pedot Modified Carbon Fiber Electrode, P. A. Reshani H. Perera Jan 2009

Nitric Oxide Synthase In Confined Environments;Detection And Quantification Of Nitric Oxide Released From Cells And Modified Liposomes Using A Sensitive Metal Catalyst-Pedot Modified Carbon Fiber Electrode, P. A. Reshani H. Perera

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Nitric oxide (NO) is a freely diffusible, gaseous free radical, associated with many physiological and pathological processes that include neuronal signaling, immune response, and inflammatory response. NO is produced from L-arginine in an NADPH-dependent reaction catalyzed by a family of nitric oxide synthase (NOS) enzymes. A deficiency in NO plays a role in hypertension, hyperglycaemia, and arteriosclerosis, among other pathological states. Conversely, increased NO levels contribute to arthritis, septic shock, and hypotention. Therefore, measuring and quantifying NO production in biological systems and matrices may be vital in elucidating physiological and pathological processes. The goal of this work is to develop …


Development Of A Novel Gradient Chromatofocusing Tandem Mass Spectometry Technique For The Determination Of Cationic Compounds In Biofluids;Identification Of Caspace 3 Cleavage Sites Of Nhe-1 By High Performance Liquid Chromatography- Mass Spectrometry, Jianhua Tang Jan 2009

Development Of A Novel Gradient Chromatofocusing Tandem Mass Spectometry Technique For The Determination Of Cationic Compounds In Biofluids;Identification Of Caspace 3 Cleavage Sites Of Nhe-1 By High Performance Liquid Chromatography- Mass Spectrometry, Jianhua Tang

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In Part I, work was done to develop a novel gradient chromatofocusing liquid chromatography-tandem mass spectrometry (MS/MS) technique for the determination of ionic compounds in biological matrix. The analysis of ionic compounds poses a great challenge to current LC-MS techniques, due to the fact that there is little or no retention. These ionic compounds are eluted at almost the same time as biological matrix, which is normally directed to waste prior to connecting to the mass spectrometer. A review of current LC-MS techniques for ionic compounds is given in Chapter 1. They all have advantages and disadvantages. To retain and …


Plasma Biomarkers For Age-Related Macular Degeneration, Jiaqian Ni Jan 2009

Plasma Biomarkers For Age-Related Macular Degeneration, Jiaqian Ni

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No abstract provided.