published_or_final_version / Medical Sciences / Master / Master of Medical Sciences

M. Tech. Chemical Engineering / Cement based materials are of enormous technological importance and their satisfaction depends on being able to transport and mould them in the freshly mixed state. The problem of the degradation or concrete is of interests to modern society, not only in terms of money, but in terms of discomfort and safety. Global research show concrete consumption around the world to be second only to water. The situation clearly indicates the significance and the huge role concrete has in the construction industry and in the global economy. This work was to investigate the various methods of increasing the life span of concrete without compromising its properties. The techniques for improving the physical properties of concrete and the effect of bacterial biofilm were studied especially for sanitary floors of food processing industries. The aim of this study is to improve the physical, mechanical and microbial properties of concrete floors in food processing industries by extending the life span of concrete materials.

AlcellRTMlignin has been used commercially in adhesive preparation and brake pad linings and experimentally in animal feeds to reduce or eliminate diarrheal attacks in farm animals. Our study dealt with elucidating the antibacterial effect of AlcellRTMlignin. It would appear that adsorbance of E. coli cells to AlcellRTMlignin particles is not essential for destruction of the organism. / The antibacterial activity was delayed by the inclusion of Mg 2+ ions in the AlcellRTMlignin filtrate or in the enumeration medium (BHIA). Addition of bile salts to the enumeration medium (BHIA) enhanced the culturability loss of E. coli cells suspended in the filtrate of AlcellRTMlignin. Using FTIR methodology, it appears, that compounds of AlcellRTMlignin affect phospholipid-phospholipid and/or phospholipid-protein interactions in bacterial membranes, causing the patching of membrane phospholipids and proteins. / Additional studies are necessary to evaluate interactions of compounds of AlcellRTMlignin with bacterial cells.

Surface-induced osseointegration and antibacterial capability are very important criteria for the clinical success of titanium implants. To enhance these two criteria, an architectural hybrid system is constructed onto Ti-6Al-4V with a rough surface. First, thermal oxidation (TO), treatment with hydrogen peroxide (H2O2) and a mix of TO and H2O2 (Mixed) are used to modify the surface topography and chemistry of Ti-6Al-4V disks. Surface characterizations by the use of microscopes and spectroscopes indicate that TO can induce more favorable topography, roughness, wettability and hydroxyl group concentration on Ti-6Al-4V surfaces. Therefore, an alginate/chitosan LBL film that incorporates antibacterial nano-silver is bridged onto thermally oxidized Ti-6Al-4V alloy by mussel-inspired dopamine. The microscopies and spectrometers confirm that the hybrid system is successfully fabricated onto the Ti-6Al-4V surface while the sub-micron topography induced by TO is maintained. Bone marrow stem cell (BMSC) adhesion, proliferation and differentiation are up-regulated by the synergy of sub-micron surface produced by TO and alginate/chitosan LBL film. The incorporation of nano-silver into the hybrid system is demonstrated to inhibit the growth of Escherichia coli and Staphylococcus aureus, but not jeopardize the enhanced BMSC activities. Taken together, this thesis presents a promising strategy to fabricate novel Ti-6Al-4V implants with enhanced osseointegration and antibacterial capability.

A burn is a type of injury to the skin caused by fire, heat, electricity, chemicals, radiation or friction. It occurs in all age groups. Burn wound infection remains the leading cause of skin graft failure and one of the leading causes of burn injury related mortality. Dressings impregnated with silver compounds are the mainstay of treatment for burn wounds to prevent or combat the infection. However, most commercially available silver based wound dressings cause trauma upon removal because of adhesion to the wound bed. A recent study has shown that burn dressing related pain is linked to more severe depressive and posttraumatic stress symptoms. Furthermore, emerging resistance associated with silver based wound dressings is a growing concern. Organic N-chloramines have been in clinical use for over 180 years thanks to their effectiveness toward a broad spectrum of microorganisms, and no resistance has been yet reported. This study aimed to develop an “ideal” wound dressing with both antibacterial and atraumatic properties. Poly(ethylene terephthalate) (PET) fabrics are among the most representative base materials in burn wound dressings and thus were chosen as the substrate. Specifically, a very thin layer of polyacrylamide (PAm) hydrogel was deposited onto the surface of PET fabric via plasma activation and photopolymerization. The treated PET fabric (termed as “PET-PAm”) was characterized with attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy and water contact angle measurement. We adapted an in vitro wet-gelatin adherence model to evaluate the effect of hydrogel deposition on reducing the adherence of PET. The deposited hydrogel layer was found to lower the adherence of PET fabrics. The peeling energy of PET decreased drastically from 2231.5 J/m2 to nearly 250 J/m2 after the deposition of hydrogel. On the other hand, we have also synthesized a series of new “composite” biocides with both N-chloramine and quaternary ammonium (QA) moieties. Those “composite” biocides exert boosted killing efficiency against methicillin-resistant Staphylococcus aureus (MRSA) and multi-drug resistant (MDR) Pseudomonas aeruginosa. The deposited hydrogel layer can also serve as the reservoir for the loading of the novel N-chloramine based “composite” biocides, to achieve a both non-adherent and antibacterial wound dressing.

Thesis--Auburn University, 2008. / Abstract. Vita. Includes bibliographical references (p. 85-90).

Thesis (Ph.D.)--University of Wollonong, 2005. / Typescript. Includes bibliographical references: leaf 206-219.

Thesis (M. Sc.), Memorial University of Newfoundland, 1998. / Restricted until June 1999. Bibliography: leaves 104-110.

Thesis (PhD) - Environment and Biotechnology Centre, Faculty of Life and Social Sciences, Swinburne University of Technology, 2008. / Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy, Environment and Biotechnology Centre, Faculty of Life and Social Sciences, Swinburne University of Technology - 2008. Typescript. "July 2008". Includes bibliographical references (p. 317-336).

Thesis (Ph.D.)--University of Waikato, 2010. / Title from PDF cover (viewed July 30, 2010). Includes bibliographical references (p. 214-261)