The effects of a simulated in vitro digestion model on the viscosity of solutions comprised of high methoxyl, low methoxyl, and low methoxyl amidated pectins were examined in conjunction with a human satiety study with healthy men (n=10) and women (n=15). Participants attended 8 morning sessions with a washout period of one week after a 12 h overnight fast. Self reported measurements were taken for the satiety parameters of hunger, fullness, satisfaction and prospective food intake using 100 mm VAS scales at predetermined time intervals over the course of 3 h. Orange juice solutions of each type of fibre were formulated to be either low viscosity (LV, 0.039±0.007 Pa•s) or high viscosity (HV, 0.14±0.035 Pa•s). The apparent viscosities of an in vitro digestion model simulating the gastric and duodenal phases in the presence of hydrolytic enzymes and bile salts were reported at 10 s-1 and 50 s-1. All pectin types showed varying apparent viscosities during the gastric phases, but showed considerable reductions in viscosity after the final phase. The low-methoxyl low and high viscosity pectin beverages were associated with the greatest effect on human subjective ratings of satiety, and high methoxyl low and high viscosity pectin beverages inconsistently exerting effects on satiety. Thus, some types of pectin are able to increase perception of satiety in humans. However, there was not a strong correlation between apparent viscosity of in vitro digestive fluids and total mean AUC for satiety related questions. Thus, fiber-induced satiety cannot be explained in full by digestate viscosity alone. / NSERC

No description available.

Qualitative and quantitative ultrastructural observations have been made on myelinated fibres in the tibial and medial plantar nerves of genetically diabetic C57/BL/Ks(db/db) and age-matched nondiabetic (m/m) control mice at 9 and 15 months of age. The cross sectional area of myelinated fibres and their axons in both nerves was found to be significantly less in diabetic mice when compared with age-matched controls. No age related decrease in axon or fibre size was noted in the diabetic at either site. The number of myelin lamellae was found to be proportionate for axon size in the tibial nerve. In the medial plantar nerve regenerated and remyelinated fibres were frequently encountered in both diabetic and age-matched controls, but were more numerous in some fascicles of diabetic animals. The morphometric data from this site was more complex, plottings of myelin area against axonal area showed a greater scatter in the 15 months diabetic group, reflecting the heterogeneity of the fibre population at this site. Plotting g ratio against axon diameter provided a rather neat way of breaking the fibre population into its component parts. The index of circularity of myelinated axons did not differ between diabetic and control animals at 15 months in the tibial nerve. However, in the plantar nerve mean axonal index of circularity was found to be significantly less in diabetic mice when compared with age-matched controls at 9 and 15 months. Axonal glycogenosomes, polyglucosan bodies, axonal compartmentalisation by Schwann cell processes and Pi granules of Reich were assessed for diabetic and control mice at both sites. Only axonal glycogenosomes were significantly more numerous in the diabetic groups. The absence of a selective reduction of axonal size in the tibial nerve in the diabetic mice did not favour a primary axonopathy. As growth in tibial bone length was reduced in these mice the reduction in fibre calibre may be due to a maturational deficit; ultrastructural abnormalities in the medial plantar nerve may suggest a pressure type neuropathy. Male Sprague Dawley rats aged 20 - 21 weeks were made diabetic with streptozotocin and maintained for 2, 4 and 6 months. Myelinated fibre area increased significantly in the tibial nerve of controls over the period of study. Fibre area in the diabetic animals was significantly less than age-matched controls at 4 and 6 months but not less than onset. Axonal perimeter was found to be significantly less in diabetic animals at 2 and 6 months when compared with age-matched controls. No significant difference was detected in the cross sectional area of axons between diabetic and age-matched controls at 2 and 4 months but was significantly less in the diabetic animals at 6 months as compared with age-matched controls (P 0.05). There was no significant difference in axonal index of circularity between diabetic and age-matched controls at 4 and 6 months, mean axonal index of circularity was significantly greater in the diabetic nerves at 2 months when compared with age-matched controls. With regard to myelin sheath thickness, the number of myelin lamellae was related in various ways to axonal dimensions. The highest correlation was found when cross sectional axonal area was related to myelin area, which was estimated from number of myelin lamellae and periodicity. Regression analysis revealed that the slope for control nerves was significantly steeper than diabetics at 4 and 6 months, suggesting a greater effect on myelin area. Myelin area estimates were significantly less in diabetic at 2, 4 and 6 months when compared with age-matched controls, but not less than onset. There was no significant difference in the incidence of the various organelles between diabetic and age-matched controls at any survival period. However, there was a border line increase in axonal glycogenosomes in the diabetics at 6 months. This study may suggest that there is a maturational deficit in nerve fibre size and myelination in streptozotocin induced diabetes in the rat.

No description available.

No description available.

No description available.

No description available.

No description available.

The type and extent of surface oxidation of carbon fibres has been determined after electrochemically treating fibres in a variety of electrolyte solutions. The chemical and physical characteristics of these fibres have been evaluated using XPS, SEM, FTIR and UV spectroscopy. The fibres were anodically treated, both in a laboratory and in a commercial type cell. Fibres that have undergone commercial treatment were then incorporated into epoxy composites, the ILSSs of which were then measured. The extent of oxidation and type of surface functionality produced as a result of electrochemical treatment is shown to depend upon several factors, ie the nature of the electrolyte, the anodic potential, reaction time, the structure of the fibre surface, the pH of the electrolyte solution, and the electrolyte concentration. Surface nitrogen functionality is not produced as a result of polarising the fibres in nitric acid. It is produced, however, with treatments in solutions containing ammonium ions. The amount of surface nitrogen depends upon the concentration of these ammonium ions in the solution. In most cases, polarisations in salt solutions produce similar changes in the fibre surfaces as treatment in the acid alone. The presence of bicarbonate ions tend to inhibit fibre surface oxidation. In acidic solutions the fibres are shown to be extensively oxidised. Although the functionality of the oxide layer produced is very similar Ge. consisting of keto- and carboxyl/ester groups) after all the acidic treatments studied, the surface topography of the oxide layer produced is very different. In all cases this oxide layer is loosely bound to the bulk fibre. In general, as reaction time increases, oxidation of the fibre surfaces also increases. Surface oxidation also increases with potential. However at high potentials (-3V) and long reaction times (>15mins) the detected functionality of type 11 fibres decreases. This is thought to be due to the formation of gaseous products such as carbon dioxide. The reactivity of type I and type II fibre is shown to be different. The amount of carboxyl/ester functionality produced is far greater for type 11 fibres. It is concluded that carboxyl functionality is produced at the edge sites and keto-type functionality on the basal planes. The amount of oxidation decreases as the pH increases. In alkaline solutions carboxyl and alcohol groups are produced, (the former being in greater quantities). The physical mechanism of oxidation is also different. Instead of an overall oxide layer being produced (in acidic solutions), holes are produced in the fibre surfaces. These holes are thought to be areas of localised attack. It is also shown, using a small pilot plant, that both galvanostatic and. potentiostatic control of electrolysis are satisfactory in producing treated fibres, which when incorporated into resins form composites with a high ILSS. The ILSS of the composites produced are dependent neither upon the amount of surface oxygen present nor upon the number of carboxyl groups present.

Thesis (PhD) - Swinburne University of Technology, Faculty of Engineering and Industrial Sciences, Centre for Micro-Photonics, 2007. / A thesis submitted for the degree of Doctor of Philosophy, Centre for Micro-Photonics, Faculty of Engineering and Industrial Sciences, Swinburne University of Technology, 2007. Typescript. Bibliography: p. 146-162.