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The sugars and organic acids present in the pulp of Keitt mangoes at various stages of ripeness were analysed by h.p.1.c. Ripening was associated with a loss in firmness, peel chlorophyll and pulp acidity, with increasing soluble solids and total sugars. The major sugars were identified as glucose, fructose and sucrose. All three increased during ripening; sucrose was found to be in the greatest concentration throughout, with fructose the predominant reducing sugar. Acidity loss was shown by decreasing titratable acidity and increasing pH values. Citric and malic acids were found to be the major organic acids. A large decrease in citric acid and a small reduction in malic acid were responsible for the loss of acidity. Tartaric, ascorbic, oxalic and a-ketoglutaric acids were also shown to be present at low concentrations.

The main goal of this study was to examine an integrative model in which academic motivation was hypothesized to mediate the relationships between dispositional optimism and pessimism and coping utilization during the preparation for midterm exams. A sample of 299 undergraduate students completed measures of optimism and academic motivation two weeks prior to midterm exams and measures of academic motivation and coping two weeks after midterm exams. Results of structural equation modeling indicated that self-determined motivation mediated the relationship between dispositional optimism and task-oriented coping, whereas non-self-determined motivation mediated the relationship between dispositional pessimism and disengagement-oriented coping. Furthermore, task-oriented coping was associated with an increase in self-determined motivation from Time 1 to Time 2, whereas disengagement-oriented coping related to an increase in non-selfdetermined motivation.

The effects of temperature on the ripening of Tommy Atkins mango were studied. Ripening temperature can affect fruit colour, flavour and texture development differently. Fruits at 12°C did not ripen to full eating quality during the 16 days of the experiment. Sugar levels were comparable with those at other temperatures, but acid levels were higher; they retained some green coloration, had lower pulp carotenoids and showed incomplete softening. After 15 days at 17"C, fruits had softened and degreened to an acceptable level but had a poor pulp colour. They were comparatively high in sugars but were also high in acids, resulting in a low sugar:acid ratio. Fruits kept at 22, 27 and 32°C all showed the development of good quality characteristics of high chlorophyll breakdown, high pulp carotenoids, a good texture and a balanced sugar: acid ratio. Similar characteristics were shown at 37"C, although the peel generally appeared mottled and the pulp had slightly lower sugar: acid ratios.

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Protein zero (P0) glycoprotein is the major integral membrane protein of the peripheral nervous system myelin in higher vertebrates. Previous findings indicate the formation of tetrameric assemblies from studies on isolated P0. To determine whether in intact myelin the P0 exists as oligomers, we isolated myelin from sciatic nerve of Xenopus laevis and analyzed it using sodium dodecyl sulfate and urea gel electrophoresis. P0 oligomerization was confirmed using Western blotting, which showed monomeric P0 at approximately 30 kDa and oligomeric P0 at approximately 60 kDa and approximately 120 kDa. A variety of denaturing conditions failed to convert any appreciable amount of oligomer to monomer. Instead, the addition of these denaturants further increased the amount of dimer and tetramer while decreasing the amount of monomer. Native gels showed dimeric P0 without the appearance of monomer or tetramer, suggesting that dimeric P0, the most prominent form of the protein, is the most stable and likely occurs in the native myelin membrane array.

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Purpose The objective of the paper is to describe trajectories of health-related quality of life (HRQL) associated with categories of body mass index (BMI): underweight, normal weight, overweight, obese class I, and obese classes II and III. Methods Data come from the longitudinal Canadian National Population Health Survey. Analyses are based on data for 3864 males and 4745 females who were 40+ in 1998/99 and followed through 2006/07. HRQL was measured with the Health Utilities Index Mark 3. Multi-level growth modeling was used. Results HRQL declined with age. For males, there was a large HRQL decrement for being underweight; trajectories for all other BMI categories were very similar. For females being underweight was associated with higher HRQL at younger ages but lower at older ages. Otherwise for females, HRQL was ordered from highest to lowest: normal, overweight, obese class I, and obese classes II and III. Conclusions Given that excess weight is a risk factor for mortality and the development of chronic conditions, the HRQL results for males are surprising. The HRQL results for females may reflect both the importance of body image on mental health and the health effects of excess weight.