3 resultados para ADVANCED GLYCATION END PRODUCTS (AGE)

em DigitalCommons@University of Nebraska - Lincoln


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This inquiry reveals the crucial guidance of teachers toward surveying the capacity and needs of students, the formation of ideas, acting upon ideas, fostering connections, seeing potential, making judgments, and arranging conditions. Each aesthetic trace causes me to wonder how teachers learn to create experiences that foster student participation in the world aesthetically. The following considerations surface: • Given the emphasis in schools on outcomes and results, how do we encourage teachers to focus on acts of mind instead of end products in their work with students? • Given the orientations toward technical rationality, to fixed sequence, how do we help teachers experience fluid, purposeful learning adventures with students in which the imagi¬nation is given room to play? • Given the tendency to conceive of planning in teaching as the deciding of everything in advance, how do we help teachers and students become attuned to making good judgments derived from within learning experiences? • How do we help teachers build dialogical multivoiced conversations instead of monolithic curriculum? • What do we do to recover the pleasure dwelling in subject matter? How do we get teachers and students to engage thoughtfully in meaningful learning as opposed to covering curriculum7 • A capacity to attend sensitively, to perceive the complexity of relationships coming together in any teaching/learning experience seems critical. How do we help teachers and students attend to the unity of a learning experience and the play of meanings that arises from such undergoing and doing? The traces, patterns, and texture evidenced locate tremendous hope and wondrous possibilities alive within aesthetic teaching/learning encounters. It is such aliveness I encountered in the grade 4 art classroom that opened this account and continues to compel my attention. Possibilities for teaching, learning, and teacher education emerge. I am convinced they are most worthy of continued pursuit.

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The reaction of living anionic polymers with 2,2,5,5-tetramethyl-1-(3-bromopropyl)-1-aza-2,5- disilacyclopentane (1) was investigated using coupled thin layer chromatography and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Structures of byproducts as well as the major product were determined. The anionic initiator having a protected primary amine functional group, 2,2,5,5-tetramethyl- 1-(3-lithiopropyl)-1-aza-2,5-disilacyclopentane (2), was synthesized using all-glass high-vacuum techniques, which allows the long-term stability of this initiator to be maintained. The use of 2 in the preparation of well-defined aliphatic primary amine R-end-functionalized polystyrene and poly(methyl methacrylate) was investigated. Primary amino R-end-functionalized poly(methyl methacrylate) can be obtained near-quantitatively by reacting 2 with 1,1-diphenylethylene in tetrahydrofuran at room temperature prior to polymerizing methyl methacrylate at -78 °C. When 2 is used to initiate styrene at room temperature in benzene, an additive such as N,N,N',N'- tetramethylethylenediamine is necessary to activate the polymerization. However, although the resulting polymers have narrow molecular weight distributions and well-controlled molecular weights, our mass spectra data suggest that the yield of primary amine α-end-functionalized polystyrene from these syntheses is very low. The majority of the products are methyl α-end-functionalized polystyrene.

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The modification of proteins by reducing sugars is a process that occurs naturally in the body. This process, which is known as glycation, has been linked to many of the chronic complications encountered during diabetes. Glycation has also been linked to changes in the binding of human serum albumin (HSA) to several drugs and small solutes in the body. While these effects are known, there is little information that explains why these changes in binding occur. The goal of this project was to obtain qualitative and quantitative information about glycation that occurs on HSA. The first section of this dissertation examined methods that could be used to quantify and identify glycation that occurs on HSA. The extent of glycation that occurred on HSA was quantified using oxygen-18 labeling mass spectrometry and the glycation sites were identified by observing the mass-to-charge (m/z) shifts that occurred in glycated HSA. This initial investigation revealed that oxygen-18 labeling based quantitation can be improved over previous methods if a relative comparison is done with oxygen-18 labeled peptides in a control HSA sample. Similarly, the process of making m/z shift-based assignments could be improved if only the peptides that were unique to the glycated HSA samples were used with internal calibration. These techniques were used in subsequent chapters for the assignment of early and late-stage glycation products on HSA. The regions of HSA that contained the highest amount of modification were identified, quantified, and ranked in order of their relative abundance. Of the commonly reported glycation sites, the N-terminus was found to have the highest extent of modification, followed by lysines 525, 199, and 439. The relative amount of modification on lysine 281, with respect to the aforementioned residues, varied with different degrees of glycation. The oxygen-18 labeling approach used for this analysis was novel because it allowed for the simultaneous quantification of all glycation-related modifications that were occurring on HSA. As such, several arginine residues were also found to have high amounts of modification on glycated HSA.