Introduction Contact lenses suffer from the same problems of deposition that other biomaterials exhibit, being rapidly coated with a variety of proteins, lipids and mucins. The first event observed at the interface between a contact lens and tear fluid is protein adsorption. Protein deposits on contact lenses are associated with diminished visual acuity, dryness and discomfort and lid-related inflammatory changes. The aim of this thesis was to determine the quantity and the conformational state of lysozyme deposited on contact lens materials over various time periods and also to determine the clinical relevance of protein deposits on contact lenses. The specific aims of each chapter of this thesis were as follows: • Chapter 4: To determine the total lysozyme deposition on conventional and silicone hydrogel contact lens materials as a function of time by artificially doping lenses with 125I-labeled lysozyme. • Chapter 5: To determine the conformational state of lysozyme deposited on conventional and silicone hydrogel contact lens materials as a function of time using an in vitro model. • Chapter 6: To quantify the total protein, total lysozyme and the conformational state of lysozyme deposited on a novel, lathe-cut silicone hydrogel contact lens material after three-months of wear. • Chapter 7: To determine the relationship between protein deposition and clinical signs & symptoms after one-day wear of etafilcon lenses in a group of symptomatic and asymptomatic lens wearers. • Chapter 8: To determine the influence of individual tear proteins (lysozyme, lactoferrin and albumin) on the adhesion of Gram positive and Gram negative bacteria to conventional and silicone hydrogel contact lens materials. Methods • Chapter 4: Conventional hydrogel FDA group I (polymacon), group II (alphafilcon A and omafilcon A), group IV (etafilcon A and vifilcon A), polymethyl methacrylate and silicone hydrogel lens materials (lotrafilcon A, lotrafilcon B, balafilcon A, galyfilcon A and senofilcon A) were incubated in a lysozyme solution containing 125I-labeled lysozyme for time periods ranging from 1 hour to 28 days. After each time period, lysozyme deposited on contact lens materials was determined using a Gamma Counter. • Chapter 5: Conventional hydrogel FDA groups I, II, IV and silicone hydrogel lens materials were incubated in lysozyme solution for time periods ranging from 1 hour to 28 days. After each time period, the lysozyme deposited on the lenses was extracted and the sample extracts were assessed for lysozyme activity and total lysozyme. • Chapter 6: 24 subjects completed a prospective, bilateral, daily-wear, nine month clinical evaluation in which the subjects were fitted with a novel, custom-made, lathe-cut silicone hydrogel lens material (sifilcon A). After 3 months of wear, the lenses were collected and total protein, total lysozyme and active lysozyme deposition were assessed. • Chapter 7: 30 adapted soft contact lens wearers (16 symptomatic and 14 asymptomatic) were fitted with etafilcon lenses. Objective measures and subjective symptoms were assessed at baseline and after hours 2, 4, 6 and 8. After 2, 4, 6 and 8 hour time points, lenses were collected and total protein, total lysozyme and active lysozyme deposition were assessed. • Chapter 8: Three silicone hydrogel (balafilcon A, lotrafilcon B & senofilcon A) and one conventional hydrogel (etafilcon A) lens materials were coated with lysozyme, lactoferrin and albumin. Uncoated and protein-coated contact lens samples were incubated in a bacterial suspension of Staphylococcus aureus 31 and two strains of Pseudomonas aeruginosa (6294 & 6206). The total counts and the viable counts of the adhered bacteria were assayed. Results • Chapter 4: Lysozyme accumulated rapidly on conventional hydrogel FDA group IV lenses, reached a maximum on day 7 and then plateaued with no further increase. PMMA showed a deposition pattern similar to that seen on lotrafilcon A and lotrafilcon B silicone hydrogel lenses. After 28 days, conventional hydrogel FDA group IV lenses deposited the most lysozyme. • Chapter 5: After 28 days, lysozyme deposited on group IV lenses exhibited the greatest activity. Lysozyme deposited on polymacon, lotrafilcon A and lotrafilcon B exhibited the lowest activity. Lysozyme deposited on omafilcon, galyfilcon, senofilcon, and balafilcon exhibited intermediate activity. • Chapter 6: The total protein recovered from the custom-made lenses was 5.3±2.3 µg/lens and the total lysozyme was 2.4±1.2 µg/lens. The denatured lysozyme found on the lenses was 1.9±1.0 µg/lens and the percentage of lysozyme denatured was 80±10%. • Chapter 7: Correlations between subjective symptoms and protein deposition showed poor correlations for total protein/ lysozyme and any subjective factor, and only weak correlations between dryness and active lysozyme. However, stronger correlations were found between active lysozyme and subjective comfort. • Chapter 8: Different tear proteins had varying effects on the adhesion of bacteria to contact lens materials. Lysozyme deposits on contact lenses increased the adhesion of Gram positive Staphyloccocus aureus 31 strain, while albumin deposits increased the adhesion of both the Gram positive Staphyloccocus aureus and Gram negative Pseudomonas aeruginosa 6206 & 6294 strains. Lactoferrin deposits increased the total counts of both the Gram positive and Gram negative strains, while they reduce the viable counts of the Gram negative strains. Conclusions • Chapter 4: Lysozyme deposition is driven by both the bulk chemistry and also the surface properties of conventional and silicone hydrogel contact lens materials. The surface modification processes or surface-active monomers on silicone hydrogel lens materials also play a significant role in lysozyme deposition. • Chapter 5: The reduction in the activity of lysozyme deposited on contact lens materials is time dependent and the rate of reduction varies between lens materials. This variation in activity recovered from lenses could be due to the differences in surface/ bulk material properties or the location of lysozyme on these lenses. • Chapter 6: Even after three-months of wear, the quantity of protein and the conformational state of lysozyme deposited on these novel lens materials was very similar to that found on similar surface-coated silicone hydrogel lenses after two to four weeks of wear. These results indicate that extended use of the sifilcon A material is not deleterious in terms of the quantity and quality of protein deposited on the lens. • Chapter 7: In addition to investigating the total protein deposited on contact lenses, it is of significant clinical relevance to determine the conformational state of the deposited protein. • Chapter 8: Uncoated silicone hydrogel lens materials bind more Gram positive and Gram negative bacteria than uncoated conventional hydrogel lens materials. Lysozyme deposited on contact lens materials does not possess antibacterial activity against all bacterial strains tested, while lactoferrin possess an antibacterial effect against certain Gram negative strains tested in this study. This thesis has provided hitherto unavailable information on contact lens deposition and its influence on subjective symptoms and bacterial binding. These results suggest that protein deposition has a significant potential to cause problems. Therefore, it is important that practitioners advise their patients regarding the importance of lens disinfection and cleaning and appropriate lens replacement schedules. These results will also be useful for the contact lens industry and the general field of biomaterials research.

This experiment produces a new flexible heat pipe, and further tests and explores its characteristics and performance. The heat pipe is made of silicone rubber, a kind of polymer material, and was molded by hot embossing. Characteristics of this material include good bending resistance, lightness, and good resistance to high temperature. Furthermore, copper sheets connected with silicone were placed at the evaporator section and condenser section to enhance heat transfer effects. DI water in the pipe was used as the working medium, and two-layer 250 mesh copper nets were used as a wick to strengthen the heat pipe¡¦s capillary effects. The researcher set the vacuum degree at 0.0658 atm to test the pipe¡¦s performances at different powers. Key findings include an optimum filling ratio of 40%, and a largest heat flux of 11.75 W/cm2 during the proficiency test. In addition to the proficiency test . The influence of different angles of bends (0 ~ -90¢X) on the pipe¡¦s heat transfer performance was also tested and based on heat thermal resistance obtained, found that the best bended angle of the flexible heat pipe was -15¢X, and thermal resistance will increase with the angle(-30 ~ -90¢X). The experiment proves a small angle bend that is helpful for the working medium to flow back to the evaporator section, but the heat transfer performance would shrink because the wick could not affix to the inner wall of the pipe if the angle is too large. This work shows the proper combination of pipe parameters will significantly improve heat transfer performance.

The object of this thesis is to discuss an experimental composite conservation process and its significance for the future of artifact conservation. Composite artifacts are artifacts comprised of multiple materials such as wood, iron, and brass. The experiment was designed around five Civil War Enfield rifles from the wreck of the Civil War blockade runner Modern Greece. The main conservation difficulty for both metal and wood from a saltwater site is the presence of chlorides. If not removed, the chlorides will cause the metals to further corrode. If the chlorides are left within the wood, once the wood dries the chlorides will crystallize and burst remaining cellular structure. The second major problem for wood is the cellular structure itself. Degraded waterlogged wood loses most of its cellular structure while submerged and this must be reinforced prior to drying or partial to total collapse of the wood will occur. Composite artifacts pose one more serious problem, their composite nature. In most instances treatments for one material type are damaging to the other materials present. Disassembly of an artifact often has detrimental effects on the whole artifact whether through initial damage or the inability to reassemble the artifact after stabilization. In 1979, four Enfield rifles from Modern Greece were compositely conserved using either tetraethyl orthosilicate, sucrose, or isopropyl rosin. All three treatments focused on the conservation of the wood, resulting in the current poor condition of the iron elements. The research of this thesis uses the combined treatments of silicone oil (to treat the wood) and electrolytic reduction [ER] (to stabilize the metals), with minimal disassembly. It was discovered that prolonged exposure of the wood elements during ER had deleterious effects, post the silicone oil treatment. This prompted a re-evaluation of the research strategy. It was determined to do a re-treatment of the wood components of four of the rifles with silicone oil after the ER process. It was apparent during the ER process that iron components had loosened and could be removed allowing the wood to be extracted from the ER process earlier than the iron. Even though the experiment did not go as planned and the initial results were undesirable, valuable information was ascertained for treatment strategies and positive results are expected for the final four rifles. The retreatment of the wood with silicone oil should allow the wood to retain its shape, making reassembly possible.

The purpose of this study was to explore the feasibility of re-treating artifacts previously conserved by PEG impregnation with alkoxysilanes. The study tried to evaluate pros and cons of re-conserving artifacts with this type of silanes. A series of experiments were conducted focusing on small, wood samples from the Vasa Museum Collection, to test different re-conservation methods. Three different procedures involving alkoxysilanes were implemented in order to re-conserve the samples. The study revealed the techniques are an efficient re-conservation method in which highly satisfactory results can be achieved. The re-treated samples present minimal volumetric distortion without significant collapse or shrinkage of the wood structures. This minimal distortion is primarily produced by the transition from swollen waterlogged wood to a dry conserved wood, and not as a result of collapse or shrinkage during treatment. Due to the negligible thickness of the polymer coating (a few microns), the samples acquire physical properties extremely close to the original dry wood. Moreover, other physiochemical properties are obtained from the consolidation with alkoxysilanes; the re-conserved wood becomes hydrophobic, chemically inert, resistant to chemical attacks (e.g., acids or bases), and resistant to ultraviolet light. These newly acquired characteristics drastically reduce the preventive conservation measures needed in museum display cabinets or during transport. Despite the excellent results, the procedure is not reversible, thus does not comply with one of the main premises traditionally accepted in conservation. Therefore, a careful study assessing benefits and disadvantages in a case-by-case basis should be assessed by conservators, restorers, and curators before applying this method to waterlogged material culture.

No description available.

<p>The need for safe and functional implants has led to anincreased demand for improved biomaterials. The performance invivo depends on the interaction between the biologicalsurrounding and the surface of the material. By tailoring thesurface of a material with suitable bulk properties,biomaterials with an ability to interact with the biologicalsystem in a specific and controlled way are obtained. Siliconeelastomers have been used as biomaterials for several decades,but it is widely recognized that they are difficult to modifyby the conventional methods used for organic polymers due tothe partly inorganic structure of silicone.</p><p>This thesis presents a strategy to obtain siliconebiomaterials by covalent coupling of molecules to the surfaceusing silicon chemistry. The first step is to introduce Si-Hgroups onto the surface of silicone elastomers by plasmatreatment. The second step is to react a terminal double bondof a molecule with the formed Si-H group by a catalyzedhydrosilylation reaction. The coupled molecule may eitherprovide the desired properties itself, or have a functionalitythat is able to couple another molecule with suitablecharacteristics.</p><p>The influence of plasma treatment in hydrogen, argon andoxygen on the silicone elastomer was characterized by X-rayphotoelectron spectroscopy (XPS). To quantify the effect ofplasma treatment, the method of ternary XPS diagrams wasdeveloped. It was found that undesired silica-like layers wereformed under severe treatment conditions. Argon plasma at lowpower and short treatment time was the most suitable parametersetting. Subsequent hydrosilylation grafting ofallyltetrafluoroethylether, aminopropylvinylether andN-vinylformamide showed that it was possible to functionalizethe surface via a covalent link to the surface. The primaryamino groups introduced onto the surface were accessible forfurther coupling reactions. Heparin surfaces were obtained by acoupling reaction with the introduced amino groups.</p><p><b>Keywords:</b>Silicone elastomers, PDMS, XPS, ESCA, surfacemodification, plasma</p>

<p>The main objective of this investigation is to determine the effect of different physical and chemical parameters on the performance of biofilters, treating hydrophobic organic compounds. pinene was used as a model substance. Alpha-pinene is commonly found in wood, and therefore found at wood storage facilities and wood processing industries [1].</p><p>In this experiment two biofilter which were in equal size, were used. Both of them were filled with perlite for treating the alpha pinene contaminated air. One of the columns contained perlite partially coated with silicone oil to make the surface of perlite more hydrophobic. The filters were run at 5, 2.5 and 1.5 l min-1 air flow rate. The results showed that the silicone oil amended filter performed better at 2.5 l/min with a maximum removal rate of 20 g / (m3 h) in comparison with 15 g/ (m3 h) for the filter without oil. The efficiency was approximately the same for both filters at 1.5 and 5 l/min (40 compare to 35 g/m3 bed h). The flow rate was then set to 2.5 l/min once more. The results showed that the removal rate had increased to approximately 35 g/ (m3 h) and that the efficiency of both filters was approximately the same. The difference in results between the initial run and the later at 2.5 l/min is probably depending on that the microorganisms had become adapted to the α-pinene and that the microorganism communities developed differently in the two filters.</p> / <p>Syftet med denna studie var att undersöka om en ökning av biofilterytans hydrofobicitet kan förbättra effektiviteten med avseende på nedbrytning av en hydrofob förening såsom -pinen. En hydrofob yta skulle kunna medföra en ökning i adsorption av hydrofoba föroreningar vilket i sin tur skulle kunna öka tillgängligheten hos föroreningarna för mikroorganismerna. Försöken utfördes med hjälp av två biofilter fyllda med perlit. Ett filter fylldes med obehandlad perlit medan det andra filtret fylldes med perlit som blandats med silikonlja. Båda filtren ympades med mikroorganismer som växt på träflis. Dessa mikroorganismer är anpassade för att bryta ner -pinen då denna förening friges i stora mängder från trä. Resultaten visar att filtret innehållande perlit täckt med silikonolja var mer effektivt med avseende på nedbrytning avpinen under den första tiden av studien (de första 30 dagarna). Skillnaden i effektivitet mellan filtren minskade dock betydligt med tiden så att skillnaden inte var signifikant under resten av studien. Prover från vätskefasen från de båda filtren undersöktes i mikroskop. Dessa studier visade att olika mikroorganismer dominerade i de båda filtren. Filtret innehållande oljetäckt perlit dominerades av stavformiga bakterier medan filtret innehållande obehandlad perlit dominerades av kocker. Båda filtren innehöll en blandkultur av kocker och stavar. Dessutom växte svamp i båda filtren. Dessa resultat visar att en förändring av ytans hydrofobicitet inte bara kan leda till en ökad adsorption av förorening utan den kan också leda till att andra mikroorganismer får en dominerande roll i filtret. Den maximala nedbrytningshastigheten låg mellan 35 och 40 g pinen/(m3h) under hela studien förutom de 30 första dagarna oberoende av luftflödeshastighet (1,5 , 2,5 respektive 5 l/min). Den maximala nedbrytningshastigheten under inledningen av försöket var 15 g/(m3 h) för filtret innehållande obehandlad perlit och 20 g/(m3h) för filtret innehållande oljetäckt perlit. Luftflödet var 2,5 l/min under den inledande perioden. Ökningen i nedbrytningshastighet med tiden indikerar att mikroorganismerna anpassade sig till miljön. Den relativt konstanta nedbrytningshastigheten under resten av studien indikerar att det var de biokemiska reaktionerna som var hastighetsbegränsande och att masstransporten inte hade någon dominerande roll med avseende på att begränsa hastigheten.</p>

Aachen, Techn. Hochsch., Thesis (doctoral), 2001.

Triarylamine type materials with vastly altered physical properties are synthesized by hybridizing organic semiconducting structures with silicone and siloxane groups. By altering the silicon content of these materials, we can tune their physical composition from free flowing liquids, to amorphous glasses, to cross-linked films. Much of this modification is enabled by the unique use of a metal-free Si-H activation chemistry; the Piers-Rubinsztajn reaction. This chemistry is demonstrated to be a general and rapid way to build up hybrid semiconducting structures. Key to the utility of these materials in electronic devices, it is shown that hybridization with silicon groups has a negligible effect on the useful electrochemical properties of the base materials. Building on this, it is shown that charge carrier mobility through a prototypical liquid organic semiconductor is similar to the base materials and transport is described by existing dispersive transport theories. Finally, two side projects in the area of organic electronics are discussed. New phthalonitrile based fluorophores are characterized and their utility as deep-blue emitting dopants in organic light emitting diodes is demonstrated. These same π-extended phthalonitriles can also be used as precursors to new red-shifted BsubPcs which display exceptional electrochemical stability and tuning.

Triarylamine type materials with vastly altered physical properties are synthesized by hybridizing organic semiconducting structures with silicone and siloxane groups. By altering the silicon content of these materials, we can tune their physical composition from free flowing liquids, to amorphous glasses, to cross-linked films. Much of this modification is enabled by the unique use of a metal-free Si-H activation chemistry; the Piers-Rubinsztajn reaction. This chemistry is demonstrated to be a general and rapid way to build up hybrid semiconducting structures. Key to the utility of these materials in electronic devices, it is shown that hybridization with silicon groups has a negligible effect on the useful electrochemical properties of the base materials. Building on this, it is shown that charge carrier mobility through a prototypical liquid organic semiconductor is similar to the base materials and transport is described by existing dispersive transport theories. Finally, two side projects in the area of organic electronics are discussed. New phthalonitrile based fluorophores are characterized and their utility as deep-blue emitting dopants in organic light emitting diodes is demonstrated. These same π-extended phthalonitriles can also be used as precursors to new red-shifted BsubPcs which display exceptional electrochemical stability and tuning.