A large portion of an airport property is occupied by runways and taxiways, which must be kept in excellent condition to ensure the safety of the airplanes, and the people on board. Any free objects on the airfield can cause damage to aircraft and are a possible danger to both the airplanes and the passengers. However, deterioration of the concrete airfield can be a major hazard and the presence of de-icing and anti-icing fluids may accelerate degradation. The focus of this project was the evaluation and assessment of aircraft de-icing and anti-icing fluids on the deterioration of airfield concrete. These fluids are used to remove and prevent snow and ice formation on aircraft by lowering the freezing temperature of water. The primary component in both fluids is ethylene glycol, while additives, which are proprietary and unknown, are mixed in to control various properties. Very little research has been done regarding the effect of the de-icer and anti-icers on the concrete deterioration. The aim of this study was to gain a better understanding of its influence on the deterioration of airfield concrete through a series of mechanical and electro-chemical tests, as well as microscopic and elemental analysis. Based on the comparative experiments and analyses performed using water, ethylene glycol, de-icer, and anti-icer, it appears that de-icing fluids do not prematurely cause concrete deterioration. In addition, experimental procedures in this study utilized the de-icing fluids as a concentrate, which are unrealistic conditions on an airfield, where dilution occurs from the addition of water and the presence of snow and ice. There was precipitate formation in all cases of cement paste exposure to de-icing fluid, however, which indicates that reactions are occurring and should be investigated further to determine the long term effects on concrete. With respect to the scope of this study, it was determined that the use of de-icers and anti-icers cause no significant detrimental effects on concrete mechanical properties and durability.

A large portion of an airport property is occupied by runways and taxiways, which must be kept in excellent condition to ensure the safety of the airplanes, and the people on board. Any free objects on the airfield can cause damage to aircraft and are a possible danger to both the airplanes and the passengers. However, deterioration of the concrete airfield can be a major hazard and the presence of de-icing and anti-icing fluids may accelerate degradation. The focus of this project was the evaluation and assessment of aircraft de-icing and anti-icing fluids on the deterioration of airfield concrete. These fluids are used to remove and prevent snow and ice formation on aircraft by lowering the freezing temperature of water. The primary component in both fluids is ethylene glycol, while additives, which are proprietary and unknown, are mixed in to control various properties. Very little research has been done regarding the effect of the de-icer and anti-icers on the concrete deterioration. The aim of this study was to gain a better understanding of its influence on the deterioration of airfield concrete through a series of mechanical and electro-chemical tests, as well as microscopic and elemental analysis. Based on the comparative experiments and analyses performed using water, ethylene glycol, de-icer, and anti-icer, it appears that de-icing fluids do not prematurely cause concrete deterioration. In addition, experimental procedures in this study utilized the de-icing fluids as a concentrate, which are unrealistic conditions on an airfield, where dilution occurs from the addition of water and the presence of snow and ice. There was precipitate formation in all cases of cement paste exposure to de-icing fluid, however, which indicates that reactions are occurring and should be investigated further to determine the long term effects on concrete. With respect to the scope of this study, it was determined that the use of de-icers and anti-icers cause no significant detrimental effects on concrete mechanical properties and durability.

Early-lactating dairy cows mobilize body protein, primarily from skeletal muscle, to provide amino acids which are directed towards gluconeogenesis and milk protein synthesis. Propylene glycol (PG) is a precursor of ruminal propionate, and our hypothesis was that its dietary inclusion could attenuate skeletal muscle wasting by reducing amino acid-driven gluconeogenesis. The major objectives of this study were to delineate the effects of pre- and post-partum PG supplementation in transition dairy cows on whole-body nitrogen (N) balance, urinary 3-methylhistidine (3-MH) excretion, body composition, and gene expression profiles for the major protein degradation pathways in skeletal muscle. Sixteen pregnant cows (7 primiparous and 9 multiparous) were paired based on expected calving dates and then randomly assigned within each pair to either a basal diet (control) or basal diet plus 600 mL/d of PG (PG). Diets were fed twice daily for ad libitum intake, and PG was fed in equal amounts as a top dress. All measurements were conducted at 3 time intervals starting at d -14 ± 5, d 15 and d 38 relative to calving. Propylene glycol had no effect (P > 0.05) on whole-body N balance, urinary 3-MH excretion, and body composition. However, N balance was lower (P < 0.001) at d 15 and d 38, compared to d -14. Urinary excretion of 3-MH was lower at d -14 than at d 15 (P = 0.01) and d 38 (P = 0.001). Supplemental PG had no effect (P > 0.05) on body weight (BW), and all components of empty BW. On average, cows fed both diets mobilized 19 kg of body fat and 14 kg of body protein between d -14 and d 38. Supplemental PG had no effect on mRNA abundance in skeletal muscle for m-calpain (P = 0.96) and 14-kDa ubiquitin-carrier protein E2 (14-kDa E2) (P = 0.54); however, PG supplementation down-regulated mRNA expression for µ-calpain at d 15 (P = 0.02), and tended to down-regulate mRNA expression for ubiquitin at d 15 (P = 0.07) and proteasome 26S subunit-ATPase at d 38 (P = 0.097). Relative to calving, mRNA abundance for m-calpain (P = 0.02) and µ-calpain (P = 0.005) were higher at d 15 compared to d -14 and d 38. Messenger RNA abundance for ubiquitin (P = 0.07) and 14-kDa E2 (P = 0.005) were lower at d 38 compared to d 15. In summary, these results demonstrate that up-regulation of the Ca2+-dependent and ubiquitin-mediated proteolytic pathways are the mechanisms by which skeletal muscle wasting occurs in early-lactating cows. In addition, dietary supplementation with PG may down-regulate some of these proteolytic pathways, thereby potentially attenuating undesirable skeletal muscle wasting.

No description available.

In recent years, biodegradable polymeric systems have gained importance for design of surgical devices, artificial organs, drug delivery systems with different routes of administration, carriers of immobilized enzymes and cells, biosensors, ocular inserts, and materials for orthopedic applications. Polysaccharide-based polymers represent a major class of biomaterials, which includes agarose, alginate, dextran, and chitosan. Chitosan has found many biomedical applications, including tissue engineering, owing to its biocompatibility, low toxicity, and degradation in the body, which has opened up avenues for modulating drug release in vivo in the treatment of various diseases. These chitosan-based delivery systems range from microparticles to nanoparticles and from gels to films. In this study, chitosan (CH) and chitosan-polyethylene glycol (CH-PEG) microspheres with different compositions were prepared by oil/water emulsion method and crosslinked with gluteraldehyde. Some microspheres were loaded with a model chemotherapeutic drug, methotrexate (MTX). SEM, particle size and in vitro release analysis were performed. In vitro drug release studies showed that the release of MTX from CH-PEG microspheres was faster compared to CH microspheres. In the second part, CH-PEG microspheres were conjugated with a monoclonal antibody which is immunoglobulin G (IgG). The cytotoxicity efficiencies of entrapped drug were determined by using MCF-7 and MCF-7/MDA-MB breast cancer cell lines. In the third part, CHF-PEG films with the same compositions as in microspheres were prepared by solvent casting method. IR, DSC, mechanical and surface analysis were performed. The mechanical properties of films were improved by the presence of proper amount of PEG but higher amounts of PEG caused the deteriotion in the properties.

We solved the problem of purification and successfully synthesized water-solubled hexaazatrinaphthylene with polyether and crown ether side chain under our biomimic and new material goal.

Abstract The polymer electrolytes (ion conducting polymers) consist of macromolecules (usually in the form of polyethereal units) that are doped with alkali mental salts. The polymer electrolytes are being used in Li-polymer buttery. It is suggested that conductivity in these systems takes place through two distinct events. The first is associated with the charge migration of ions between coordination sites in the host material, and the second is that the conductivity is generally observed to rise with increasing flexibility of the polymer chains. Rayleigh-Brillouin scattering spectra of molecular liquids will provide mechanical relaxation information in the frequency range from 10^8 to 10^11 Hz. We have carried out the Brillouin scattering study of PEG400/LiCl mixtures to probe its elastic properties. The change in the flexibility of polymer chains at different temperatures, the fraction of free ion, and their interactions with polymer all effect the Brillouin spectrum and the present work suggests the usefulness of this technique as an useful tool to probe the various interactions in polymer electrolytes.

Oligo(ethylene glycol) groups have been used as substituents in poly(p-phenyleneethynylene)s (PPEs) to provide solubility, and to boost quantum yield. Properties such as water-solubility and increased quantum yield in aqueous solution make these conjugated systems promising for biosensory applications. In this thesis, a PPE containing a branched ethylene glycol side chain is synthesized as part of a polymer array for glycan biosensing. I also report that the same side chain can be put to use in a red-emissive polymer to lend water solubility. Another monomeric unit, containing ethylene glycol chains, is incorporated into a PPE to create an ampiphilic polymer. The versatility of these polymers allows them to be used for a variety of purposes, some of which will be described herein.

Traumatic neuronal injury inevitably causes plasmalemmal damage, and sometimes leads to axonal severance. For any eukaryotic cell to survive following traumatic injury, the plasmalemma must be repaired (sealed). Plasmalemmal sealing occurs via a Ca²⁺-dependent accumulation of vesicles or other membranous structures that form a plug at the damage site. Using uniquely identified and damaged rat hippocampal B104 cells that extend neurites with axonal properties, or rat sciatic nerves, plasmalemmal sealing is assessed by exclusion of an extracellular dye from each damaged B104 cell, or sciatic nerves ex vivo. B104 cells with neurites transected nearer (<50 [micrometres]) to the soma seal at a lower frequency and slower rate compared to cells with neurites transected farther (>50 [micrometres]) from the soma. Sealing in B104 cells is enhanced by 1) increased [cAMP], 2) increased PKA activity, 3) increased Epac activity, 4) H₂O₂ and 5) Poly-ethylene glycol (PEG). Sealing is decreased by 1) PKA inhibition, 2), Botulinum toxins A, B, E, 3) Tetanus toxin 4), NEM, 5) Brefeldin A, 6) nPKC inhibition, 7) DTT, 8) Melatonin and 9) Methylene Blue. Substances (NEM, Bref A, PKI, db-cAMP, PEG) that affect plasmalemmal sealing in B104 cells in vitro have similar effects on plasmalemmal sealing in rat sciatic nerves ex vivo. Based on data from co-application of enhancers and inhibitors of sealing, I propose a plasmalemmal sealing model having four partly redundant, parallel pathways mediated by 1) PKA, 2) Epac, 3) cytosolic oxidation and 4) nPKCs. The identification and confirmation of these pathways may provide novel clinical targets for repairing and/or recovery from traumatic injury. The fusogenic compound PEG rapidly repairs axonal continuity of severed axons, potentially by rejoining severed proximal and distal axons. PEG-fusion is influenced by plasmalemmal sealing, since unsealed axons are easier to PEG fuse. I demonstrate that PEG restores morphological continuity, and improves behavioral recovery following crush-severance to sciatic nerves in rats in vivo. Co-application of Mel or MB prior to PEG application further improves PEG fusion (as measured by electrophysiology) and behavioral recovery following crush-severance in vivo. These PEG data may provide novel clinical techniques for rapidly repairing axonal severance. / text

Acute injury of major epithelial organ systems (kidney, liver, lung, etc.) is collectively a principal cause of death worldwide. Regenerative medicine promises to meet these human health challenges by harnessing intrinsic cellular processes to repair or replace damaged tissues. Epithelial morphogenesis is a hard-wired, multicellular differentiation program that dynamically integrates microenvironmental cues to coordinate cell fate processes including adhesion, migration, proliferation, and polarization. Thus, epithelial morphogenesis is an instructive mode of tissue assembly, maintenance, and repair. Three-dimensional epithelial cell cultures in natural basement membrane (BM) extracts produce hollow, spherical cyst structures and have indicated that the BM provides the critical cell adhesion ligands to facilitate cell survival, stimulate proliferation, and promote polarization and lumen formation. However, the utility of natural BMs for detailed studies is generally limited by lot-to-lot variations, uncontrolled cell adhesive interactions, or growth factor contamination. The goal of this thesis was to engineer bioartificial extracellular matrices (ECM) that would support and modulate epithelial cyst morphogenesis. We have engineered hydrogels, based on a multi-arm maleimide-terminated poly (ethylene glycol) (PEG-4MAL), that present cell adhesive molecules and enzymatic degradation substrates and promote polarized epithelial cyst differentiation in vitro. To investigate the influence of matrix physical and biochemical signals on cyst morphogenesis, we independently varied the polymer weight percentage (wt%), the density of a cell adhesion ligand (RGD), and crosslink degradation rates of the hydrogels. Then, we evaluated functional outcomes including Madin-Darby canine kidney (MDCK II) epithelial cell survival, proliferation, cyst polarization, and lumen formation. We found that cell proliferation, but not cell survival, was sensitive to the polymer wt%, which is related to elastic modulus and crosslink density. This result defined a working range of PEG-4MAL concentration (3.5% - 4.5%) that promotes robust proliferation. Analysis of mature cysts indicated that 4.0% and 4.5% gels produced cysts resembling those typically grown in type I collagen gels while 3.5% gels produced cysts with higher incidence of inverted polarity and multiple lumens. Perturbation of matrix degradability using a slow-degrading crosslink peptide or matrix metalloproteinase inhibitors showed that the rate of matrix degradation exerts major influence on cyst growth in PEG-4MAL gels. We employed 4.0% PEG-4MAL hydrogels with RGD ligand density ranging over 0 – 2000 uM to discover that (1) lumen formation was eliminated in the absence of RGD, (2) extent of lumen formation increased with increasing RGD concentration, and (3) cyst polarity was inverted below a threshold of integrin binding to RGD. Together, these results show that the biochemical and physical properties of the matrix, particularly integrin binding and matrix degradability, effectively modulate establishment of apico-basal polarity and lumen phenotypes in MDCK II epithelial cyst structures. Furthermore, these studies validate PEG-4MAL hydrogels as a powerful culture platform to enable detailed investigation of matrix-directed modulation of epithelial morphogenesis.