Injuries to the meniscus are a common and important source of mobility issues in the knees of young active individuals, as well as elderly individuals. Conventional treatments for these injuries involve surgical resections of the damaged portions of tissue in order to relieve immediate clinical symptoms. However, with a decreased amount of meniscal tissue remaining, the load-bearing and load-distribution capacities remain compromised and inevitably lead to the development of osteoarthritis.1 In view of these deficiencies, tissue engineering has emerged as a promising alternative approach to meniscus repair. In this approach, biodegradable synthetic materials have been proposed as scaffolds to stimulate and support cell-mediated tissue remodeling. A wide range of synthetic materials have been developed to respond to the physical and chemical requirements of a scaffold, but many lack the necessary biological properties to respond to cellular stimuli. In addition, many of these materials are deficient in mechanical strength. The aim of this study was to develop a novel biomaterial that addresses these limitations. Poly(trimethylene carbonate) (PTMC) was selected as the main component of the scaffold due its highly suitable material properties. PTMC is a biocompatible, biodegradable polymer with excellent elastomeric properties and mechanical strength. It also offers the advantage of providing long-term mechanical support due to its low degradation rate. However, PTMC alone cannot stimulate tissue regeneration due to its bio-inert nature. In order to provide an ideal environment to support tissue repair, it must possess bioactive signals. PTMC was combined with a collagenase-sensitive peptide substrate to render the scaffold invasive by cells. The peptide also served to increase the slow degradation rate of PTMC by providing cleavage points throughout the network. The compressive strength of this material was significantly higher than previously used scaffold materials. Additionally, the material possessed enhanced toughness and elasticity, high equilibrium water content, and a tunable degradation profile. Unlike currently used scaffolding materials, this material satisfies all of the necessary requirements to function as an effective scaffold for meniscus regeneration. / Thesis (Master, Chemical Engineering) -- Queen's University, 2013-11-20 15:36:06.12

Master of Science / Department of Animal Sciences and Industry / Barry J. Bradford / Dairy cows undergo many homeorhetic adaptations during the transition to lactation. Although many of the physiological processes - including increased lipolysis and postpartum inflammation - are adaptive, exaggerated responses can contribute to metabolic disease and reduced milk production. L-carnitine has been shown to increase hepatic oxidation of fatty acids and reduce hepatic lipid accumulation in early lactation cows; however, L-carnitine is degraded in the rumen. An experiment using 4 ruminally-cannulated Holstein heifers in a split plot design demonstrated that the relative bioavailability of L-carnitine was greater when delivered abomasally than ruminally. There was a dose × route interaction and a route effect for increases in plasma carnitine above baseline, with increases above baseline being greater across all dose levels (1, 3, and 6 g L-carnitine/d) when infused abomasally compared to ruminally. A second experiment used 56 lactating Holstein cows in a randomized complete block design to evaluate 2 rumen-protected products (40COAT and 60COAT) compared to crystalline L-carnitine at doses targeting 3 and 6 g/d carnitine. Although crystalline and 40COAT were effective in linearly increasing carnitine concentrations, only subtle responses were seen for the 60COAT, which were less than that for crystalline carnitine in plasma, milk, and urine. Ineffectiveness of rumen-protected products to increase carnitine concentrations beyond crystalline may have been due to over-encapsulation that hindered liberation of the carnitine and its absorption in the small intestine. Although L-carnitine has the potential to reduce postpartum hepatic lipidosis, effective rumen protection of L-carnitine while maintaining intestinal availability needs further investigation. Plant polyphenols have anti-inflammatory properties and when administered during the transition period, have been shown to increase milk production. An experiment used 122 multiparous Holstein cows in a randomized block design to determine the effect of short term (5-d; SBE5) and long term (60-d; SBE60) administration of Scutellaria baicalensis extract (SBE)on whole-lactation milk yield, 120-d milk component yield, and early lactation milk markers of inflammation. Whole-lactation milk yield was increased for SBE60 compared to control, but was not different for SBE5 compared to control. Greater total pellet intake, milk lactose yield, and reduced SCC during wk 1-9 for SBE60 compared to control, all could have contributed to the observed sustained increase in milk yield. Milk production parameters were not different for SBE5 compared to control. No treatment effects were observed for BCS or milk markers of inflammation (haptoglobin) and metabolic function (β-hydroxybutyrate). Overall, long term administration of S. baicalensis effectively increased milk production, however the mechanism by which this was achieved is unknown. Although routes of administration to effectively achieve their physiological responses were different between L-carnitine (abomasal delivery) and SBE (feeding), both bioactive nutrients can improve the metabolic function of early lactation dairy cows.

No description available.

Concrete structures can prematurely deteriorate due to the corrosion of reinforcing steel. Corrosion can occur through chloride ingress due to exposure to aggressive media such as seawater and deicing salts. Corrosion causes over $100 billion in damage annually. There are many corrosion mitigation techniques on the market today; these techniques have limited effectiveness as demonstrated by the fact that billions of dollars are still being expended each year due to corrosion-related damage. Therefore, there is a need for innovative approaches to corrosion prevention. This research program used cinnamaldehyde (CA), a bioactive agent derived from cinnamon bark, as a method for corrosion mitigation. Although CA can prevent the corrosion of metals, its hydrophobicity has a negative effect on hydration when incorporated in cementitious systems. In order to avoid these negative consequences while harnessing the anti-corrosive properties, CA was incorporated in a cementitious mixture through the use of lightweight aggregate (LWA). Several tests were carried out to investigate the potential chemical and mechanical effects due to the addition of LWA pre-wet with CA. Promising results were observed, in which the time to corrosion was prolonged by 91 %.

Orientador: Olga Maria Mascarenhas de Faria Oliveira / Coorientador: Kátia Maria da Silva Cerqueira Leite / Banca: Giuseppina Pace Pereira Lima / Banca: Glaucia Maria Pastore / Resumo: O maracujá amarelo azedo (Passiflora edulis f. flavicarpa Degener) pode ser consumido in natura ou industrializado. Sua importância é dada pelo valor medicinal, popularmente usado no tratamento da ansiedade, insônia e irritabilidade; alimentício, na forma de polpa congelada e suco, doces, geleia e sorvete; e nutracêutico ou alimento funcional, apresentando elevados teores de íons fosfato e potássio, vitamina A, B1 (tiamina), B2 (riboflavina) e C (ácido ascórbico). Algumas alterações podem ocorrer durante o processamento e armazenamento do suco interferindo na cor e sabor do produto final, o que pode implicar em não aceitação por parte dos consumidores. Isso pode ocorrer principalmente devido a reações bioquímicas de escurecimento e alterações bioquímicas moleculares que resultam em flavors indesejáveis e perda de nutrientes. Por esse motivo o controle desses efeitos indesejáveis durante o processamento de frutos é muito importante para a preservação da aparência natural dos mesmos. Deste modo as enzimas Pectinametilesterase (PME; EC: 3.1.1.11), Peroxidase (POD; EC: 1.11.1.7), Polifenoloxidase (PPO; EC: 1.10.3.1) e Ascorbato Oxidase (AO; EC: 1.10.3.3) podem ser responsáveis pelo escurecimento enzimático e outras reações que alteram o produto durante e ao final do processamento. Visto isso, com o objetivo de agregar valores nutricionais e mercadológicos ao maracujá vem sendo desenvolvida e usada a cultura híbrida, que, em síntese, significa o uso de sementes modificadas e com manejo adequado, com vistas à racionalização do uso de defensivos agrícolas e aumento de produtividade. O objetivo desse trabalho é estudar o comportamento cinético das enzimas já citadas e avaliar os teores de compostos bioativos como vitamina C, compostos fenólicos, flavonóides, e atividade antioxidante em cinco... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The yellow passion fruit (Passiflora edulis f. flavicarpa Degener) can be eaten in natura or industrialized. Its importance is given by medicinal value, commonly used for treating anxiety, insomnia and irritability; food in the form of frozen pulp and juice, candy, jelly and ice cream, and nutraceutical or functional food, with high levels of potassium and phosphate ions, Vitamin A, B1 (thiamine), B2 (riboflavin) and C (ascorbic acid). Some changes may occur during processing and storage of the juice interfere the color and flavor of the final product, which can result in non-acceptance by the consumers. This can occur mainly due to biochemical browning and reactions molecular biochemical changes that result in undesirable flavors and nutrient loss. Therefore the control of these undesirable effects during processing of fruits is very important for preserving the natural appearance. Thus, enzymes pectinmethilesterase (PME, EC: 3.1.1.11), peroxidase (POD, EC: 1.11.1.7), Polyphenoloxidase (PPO, EC: 1.10.3.1) and ascorbate oxidase (AO, EC: 1.10.3.3) can be responsible for enzymatic browning and other reactions that alter the product during and after processing. Seen it, with the goal of adding nutritional value and market the passion fruit has been developed and used a hybrid culture, which, in summary, means the use of modified seeds and with appropriate management, with a view to rationalizing the use of pesticides and increase productivity. The aim of this work is to study the kinetic behavior of the enzymes already mentioned and evaluate the contents of bioactive compounds such as vitamin C, phenolic compounds, flavonoids and antioxidant activity of five hybrid the yellow passion fruit tart cultivar. The main results of this study was to visualize distinct kinetic behaviors of the same enzyme in hybrids studied and higher levels... (Complete abstract click electronic access below) / Mestre

Streptomyces are known to produce a large variety of antibiotics and other bioactive compounds with remarkable industrial importance. Streptomyces sp. COUK1 was found as a contaminant on a plate in which Rhodococcus erythropolis was used as a test strain in a disk diffusion assay and produced a zone of inhibition against the cultured R. erythropolis. The identity of the contaminant was confirmed as Streptomyces through 16S rRNA sequencing. This Streptomyces produces a strong inhibitory compound in different growth media. A culture extract from inorganic salts starch agar was found to be very active; producing a large zone of inhibition against several Gram positive and Gram negative test strains. The active molecules in this extract have been detected via TLC and bioautography. The difference in the antibacterial activity and chromatographic properties of extracts recovered from different growth media suggests that this Streptomyces strain could produce more than one type of inhibitory compound.

An earlier approach to restore homeostatic levels of ECM degrading matrix metalloproteases (MMPs) by the Sefton Lab utilized hydroxamate-based MMP inhibitory (MI) beads. While the MI beads delayed ECM degradation in the context of skin wound healing, they caused elevated cell infiltration in a subcutaneous implant model. The primary goal of this project was to further investigate this finding using an air pouch implant model in mice and a different control group – methacrylic acid-based (MAA) beads. Exudate analysis indicated that the MI beads, implanted subcutaneously with gelatin discs, elicited a similar biological response as the MAA beads. Exudates corresponding to both biomaterials had similar cell counts and chemokine levels, which were greater than those corresponding to the control used earlier, poly-methyl methacrylate-based (PMMA) beads. Further, both MI and MAA beads activated infiltrating macrophages in the classical manner, and influenced the activity of an MMP8 catalytic domain in a similar manner.

An earlier approach to restore homeostatic levels of ECM degrading matrix metalloproteases (MMPs) by the Sefton Lab utilized hydroxamate-based MMP inhibitory (MI) beads. While the MI beads delayed ECM degradation in the context of skin wound healing, they caused elevated cell infiltration in a subcutaneous implant model. The primary goal of this project was to further investigate this finding using an air pouch implant model in mice and a different control group – methacrylic acid-based (MAA) beads. Exudate analysis indicated that the MI beads, implanted subcutaneously with gelatin discs, elicited a similar biological response as the MAA beads. Exudates corresponding to both biomaterials had similar cell counts and chemokine levels, which were greater than those corresponding to the control used earlier, poly-methyl methacrylate-based (PMMA) beads. Further, both MI and MAA beads activated infiltrating macrophages in the classical manner, and influenced the activity of an MMP8 catalytic domain in a similar manner.

The objective of this research is to synthesize and characterize microstructures and some elastic properties of bioactive glasses subject to relaxation and/or devitrification treatments. We synthesize two kinds of bioglasses, i.e. P-richer 45S5 and P-poorer 55S4.3. After tempering, the as-prepared bioactive glasses are transparent, 55S4.3 being colorless while 45S5 pale pink in color. The thermal events in DTA analysis indicated that the crystallization of 45S5 and 55S4.3 starts at 620oC and 680oC, respectively. The two bioactive glasses became ivory upon heating at 715oC, and the degree of being opaque increases with dwelling time. The crystalline phase for 45S5 is Na2CaSiO4 -derived Na2Ca2Si3O9 or Na4CaSi3O9. By XRD traces and polarizing optical micrographs, we conclude that the crystal is based on simple cubic structure with a=7.5054Å and space group P213 (198). Due to poor crystallization rate, the crystal in P-poor 55S4.3 glass was not investigated in detail. However, according to the similarity of Raman spectra for devitrified 45S5 and 55S4.3, we suggest that the crystal is similar for the two devitrified glasses. Raman spectra indicated that the relaxed 45S5 has predominant Q2 and Q3 species and the Q3/Q2 ratio decreases with firing time at 715oC. As for relaxed 55S4.3, the major structural unit is Q3, and the intensity of Q3 is higher for 55S4.3 than 45S5. As the Na+/Si4+ ratio increases, the intensity of 946 (or 947) cm-1 increases while bands near 1100 cm-1 decrease. Based on the Raman spectra of devitrified 45S5 and 55S4.3, the crystals in the two glasses have a common structural unit of SiO32- (Q2). The elasticity measurement by Brillouin scattering indicated that the moduli for devitrified glass 45S5 are greater than undevitrified 45S5 and 55S4.3 glass. The elasticity of the present bioactive glasses is lower than hydroxyapatite and fluorapatite.

Thesis (Ph. D.)--University of Missouri-Columbia, 1996. / Typescript. Vita. Includes bibliographical references (leaves 126-141). Also available on the Internet.