112 resultados para Sharp increase

em Deakin Research Online - Australia


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The organic ionic plastic crystal material N,N-dimethyl pyrrolidinium tetrafluoroborate ([C1mpyr][BF4]) has been mixed with LiBF4 from 0 to 8 wt% and shown to exhibit enhanced ionic conductivity, especially in the higher temperature plastic crystal phases (phases II and I). The materials retain their solid state well above 100 °C with the melt not being observed up to 300 °C. Interestingly the conductivity enhancement is highest with the lowest level of LiBF4 addition in phase II, but then the order of enhancement is reversed in phase I. In all cases, a conductivity drop is observed at the II → I phase transition (105 °C) which is associated with increased order in the pure matrix, as previously reported, although the conductivity drop is least for the highest LiBF4 amount (8 wt%). The 8 wt% sample displays different conductivity behaviours compared to the lower LiBF4 concentrations, with a sharp increase above 50 °C, which is apparently not related to the formation of an amorphous phase, based on XRD data up to 120 °C. Symmetric cells, Li/OIPC/Li, were prepared and cycled at 50 °C and showed evidence of significant preconditioning with continued cycling, leading to a lower over-potential and a concomitant decrease in the cell resistivity as measured by EIS. An SEM investigation of the Li/OIPC interfaces before and after cycling suggested significant grain refinement was responsible for the decrease in cell resistance upon cycling, possibly as a result of an increased grain boundary phase.

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Plants modify metabolic processes for adaptation to low phosphate (P) conditions. Whilst transcriptomic analyses show that P deficiency changes hundreds of genes related to various metabolic processes, there is limited information available for global metabolite changes of P-deficient plants, especially for cereals. As changes in metabolites are the ultimate ‘readout’ of changes in gene expression, we profiled polar metabolites from both shoots and roots of P-deficient barley (Hordeum vulgare) using gas chromatography–mass spectrometry (GC-MS). The results showed that mildly P-deficient plants accumulated di- and trisaccharides (sucrose, maltose, raffinose and 6-kestose), especially in shoots. Severe P deficiency increased the levels of metabolites related to ammonium metabolism in addition to di- and trisaccharides, but reduced the levels of phosphorylated intermediates (glucose-6-P, fructose-6-P, inositol-1-P and glycerol-3-P) and organic acids (α-ketoglutarate, succinate, fumarate and malate). The results revealed that P-deficient plants modify carbohydrate metabolism initially to reduce P consumption, and salvage P from small P-containing metabolites when P deficiency is severe, which consequently reduced levels of organic acids in the tricarboxylic acid (TCA) cycle. The extent of the effect of severe P deficiency on ammonium metabolism was also revealed by liquid chromatography–mass spectrometry (LC-MS) quantitative analysis of free amino acids. A sharp increase in the concentrations of glutamine and asparagine was observed in both shoots and roots of severely P-deficient plants. Based on these data, a strategy for improving the ability of cereals to adapt to low P environments is proposed that involves alteration in partitioning of carbohydrates into organic acids and amino acids to enable more efficient utilization of carbon in P-deficient plants.

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Polypropylene (PP) and polystyrene (PS) blends were prepared by melt processing in a haake at 180 °C. PP/PS blends are immiscible and the blend morphologies were characterized by scanning electron microscopy. The viscoelastic properties were characterized using dynamic mechanical analysis (DMA) with reference to blend ratio. The blend morphologies such as matrix droplet and phase inverted morphologies were observed. The storage modulus of the blends increased with increase in PS content and the value was maximum for neat PS. DMA showed changes in the polystyrene glass transition temperatures (Tg) over the entire composition range. There was a sharp increase in the Tg of PS with increasing PP content in the blend and a 12 °C elevation in Tg was observed. The increase in Tg was explained by proposing a new model based on the physical interaction between the blend components. It is assumed that the different effects by the PP phase resulted in the formation of constrained PS chains leading to high Tg values. The addition of PP-g-MAH has a positive effect on the morphology, increases the storage modulus, and decreases the Tg till 80/20 blends. However, for PP/PS blends with higher concentrations of PS, the PP-g-MAH has little effect or adverse effect on the morphology, and storage modulus, but decreases the Tg.

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Making a detour can be advantageous to a migrating bird if fuel-deposition rates at stopover sites along the detour are considerably higher than at stopover sites along a more direct route. One example of an extensive migratory detour is that of the Sharp-tailed Sandpiper (Calidris acuminata), of which large numbers of juveniles are found during fall migration in western Alaska. These birds take a detour of 1500-3400 km from the most direct route between their natal range in northeastern Siberia and nonbreeding areas in Australia. We studied the autumnal fueling rates and fuel loads of 357 Sharp-tailed Sandpipers captured in western Alaska. In early September the birds increased in mass at a rate of only 0.5% of lean body mass day-1. Later in September, the rate of mass increase was about 6% of lean body mass day-1, among the highest values found among similar-sized shorebirds around the world. Some individuals more than doubled their body mass because of fuel deposition, allowing nonstop flight of between 7100 and 9800 km, presumably including a trans-oceanic flight to the southern hemisphere. Our observations indicated that predator attacks were rare in our study area, adding another potential benefit of the detour. We conclude that the most likely reason for the Alaskan detour is that it allows juvenile Sharp-tailed Sandpipers to put on large fuel stores at exceptionally high rates.

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The number of Australians who were homeless on census night increased by 17% to 105,237 in the five years to August 2011. When adjusted for population growth, the increase the increase is still worryingly high, at around 8%. It’s clear we need a stronger commitment to address this significant social issue.

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The study was conducted to examine the impact of sociocultural influences and the moderating role of self-esteem and negative affect on body dissatisfaction and body change strategies for both adolescent boys and girls. Surveys designed to assess body dissatisfaction, body change strategies to decrease weight and increase muscles, perceived sociocultural pressures to lose weight and increase muscles, self-esteem and negative affect were administered to 587 boys and 598 girls aged between 11 and 15 years. The majority of respondents were from Anglo-Australian backgrounds (83%) with the remainder being from Asian and European non-English-speaking backgrounds. The sociocultural influences were found to significantly predict body dissatisfaction and body change strategies for both boys and girls. However, in the case of boys, self-esteem was found to moderate the impact of the sociocultural influences in predicting body change strategies. It was primarily the boys with low self-esteem who were more affected by the sociocultural pressures whereas the girls were affected independently of their self-esteem. Negative affect was also found to play a moderating role on some of the sociocultural influences in predicting strategies to increase muscles. Both boys and girls with higher levels of negative affect were more likely to be affected by sociocultural messages directed at increasing muscles. The results from the present study demonstrate that as well as examining the direct influence of sociocultural pressures, it is also important to examine how these may be moderated by self-esteem and negative affect.

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This study investigated the nature of body image and body change strategies, as well as the sociocultural influences on these variables, among a group of 1,266 adolescents (622 males, 644 females). In particular, it investigated weight gain and increased muscle, as well as weight loss. It was found that females were less satisfied with their bodies and were more likely to adopt strategies to lose weight, whereas males were more likely to adopt strategies to increase weight and muscle tone. Respondents with higher body mass index (BMI) evidenced greater body dissatisfaction and more weight loss strategies, but there were no differences between BMI groups in weight gain or strategies to increase muscles. Weight gain and strategies to increase muscles were more likely to be undertaken by older adolescents, but there were no grade level differences in weight loss. Media influences to alter weight, as well as feedback from mother, father, and both male and female peers, were greater for females. There were few grade level or BMI differences in regard to any of the sociocultural influences. The importance of these findings in terms of providing a better understanding of factors which may lead to a disturbed body image and body change disorders, particularly among adolescent boys, is discussed.

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The present study was concerned with the impact of pubertal development, relationships with peers and perceived pressure from the media on body dissatisfaction and body change behaviors among adolescent boys and girls. In particular, the study investigated the underresearched area of strategies to increase weight and muscle. The exploration of body change strategies among adolescent boys has been a neglected area of research. Methods: Respondents were 1185 adolescents (527 males, 598 females) who were enrolled in Grades 7 and 9. Participants completed measures of pubertal development, media and peer influence, body dissatisfaction and strategies to lose weight, increase weight and to increase muscle. Results: The findings demonstrated that girls were more likely than boys to adopt strategies to lose weight, whereas boys were more likely to adopt strategies to increase muscle tone (but not weight). For boys in both Years 7 and 9, the main predictors of body change strategies were puberty and, to a lesser extent, perceived popularity with peers. The major influences for Years 7 and 9 girls were puberty and the media, but these mainly focused on weight loss. For Year 9 girls, perceived popularity with opposite-sex peers also predicted body dissatisfaction and strategies to increase muscle tone. Conclusion: The implications of these findings for understanding factors related to a range of body change strategies for adolescent boys and girls are discussed.

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This study examined factors that influence body image and strategies to either lose weight or increase muscle among children. Participants were 237 boys and 270 girls. Body mass index (BMI), body dissatisfaction, cognitions and behaviors to both lose weight and increase muscles, as well as self-esteem and positive and negative affect, were evaluated. Self-esteem was associated with body satisfaction, positive affect predicted strategies to lose weight and increase muscles, and negative affect predicted body dissatisfaction and cognitions to lose weight and increase muscles. Boys were more likely to focus on changing muscles. Respondents with higher BMIs were more focused on losing weight but not muscle. The discussion focuses on health risk behaviors related to eating and exercise among children.

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For some research projects, recruiting in public places is an invaluable addition to sampling strategies. It complements the more traditional recruitment strategies by providing researchers with' opportunities to include people in the research who would otherwise be excluded. One of the limitations of selective and snowball sampling is that participants often come from the same social group. Participants from these social groups often share similar experiences and ways of thinking about those experiences. The aim of recruiting in public places is to move beyond this 'in group' to ensure a wider perspective. This paper illustrates how recruiting in public places can provide greater sample diversity for theoretical strength. The paper begins with a brief overview of recruiting in public places. It then describes the theoretical considerations associated with this recruiting strategy. The paper demonstrates how recruiting in public places facilitates grounded theory by providing comparisons that are informed by diverse experiences. Using examples and a case study, we illustrate how recruiting in public places can complement selective, snowball and theoretical sampling to ensure a more comprehensive sample.

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A longitudinal study was used to examine age differences in the role of body mass index (BMI) and sociocultural pressures in predicting changes in body image and strategies to both lose weight and increase muscles among 443 children aged between 8 and 12 years (207 boys, 236 girls) over a 16-month period. The strongest predictors of body image and these strategies were BMI, the media and mothers, and to a lesser extent fathers and best friends. Girls were focused on losing weight, whereas boys were focused on both increasing muscle and losing weight. Surprisingly, there was a reduction in strategies both to lose weight and increase muscles as children approached adolescence. The implications of these findings for preventative educational programs for boys and girls are discussed.

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The heat-transfer coefficients around a workpiece immersed in an electrically heated heat treatment fluidised bed were studied. A suspension probe designed to simulate a workpiece of complex geometry was developed to measure local total and radiative heat-transfer coefficients at a high bed temperature. The probe consisted of an energy-storage region separated by insulation from the fluidised bed, except for the measuring surface, and a multi-thermocouple measurement system. Experiments in the fluidised bed were performed for a fluidising medium of 120-mesh alumina, a wide temperature range of 110–1050 °C and a fluidising number range of 1.18–4.24. It was found that the workpiece surface temperature has a more significant effect on heat transfer than the bed temperature. The total heat-transfer coefficient at the upper surface of the workpiece sharply decreased at the start of heating, and then steadily increased as heating progressed, while a sharp decrease became a rapid increase and then a slow increase for the radiative heat-transfer coefficient. A great difference in the heat-transfer coefficients around the workpiece was observed.

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Riboflavin-responsive, multiple acylcoenzyme A dehydrogenase deficiency (RR-MAD), a lipid storage myopathy, is characterized by, among others, a decrease in fatty acid (FA) ß-oxidation capacity. Muscle uncoupling protein 3 (UCP3) is up-regulated under conditions that either increase the levels of circulating free FA and/or decrease FA ß-oxidation. Using a relatively large cohort of seven RR-MAD patients, we aimed to better characterize the metabolic disturbances of this disease and to explore the possibility that it might increase UCP3 expression. A battery of biochemical and molecular tests were performed, which demonstrated decreases in FA ß-oxidation and in the activities of respiratory chain complexes I and II. These metabolic alterations were associated with increases of 3.1- and 1.7-fold in UCP3 mRNA and protein expression, respectively. All parameters were restored to control values after riboflavin treatment. We postulate that the up-regulation of UCP3 in RR-MAD is due to the accumulation of muscle FA/acylCoA. RR-MAD is an optimal model to support the hypothesis that UCP3 is involved in the outward translocation of an excess of FA from the mitochondria and to show that, in humans, the effects of FA on UCP3 expression are direct and independent of fatty acid ß-oxidation.

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To investigate the in vivo effects of resistance exercise on translational control in human skeletal muscle, we determined the phosphorylation of AMP-activated kinase (AMPK), eukaryotic initiation factor 4E-binding protein (4E-BP1), p70/p85-S6 protein kinase (S6K1), and ribosomal S6 protein (S6). Furthermore, we investigated whether changes in the phosphorylation of S6K1 are muscle fiber type specific. Eight male subjects performed a single high-intensity resistance exercise session. Muscle biopsies were collected before and immediately after exercise and after 30 and 120 min of postexercise recovery. The phosphorylation statuses of AMPK, 4E-BP1, S6K1, and S6 were determined by Western blotting with phospho-specific and pan antibodies. To determine fiber type-specific changes in the phosphorylation status of S6K1, immunofluorescence microscopy was applied. AMPK phosphorylation was increased approximately threefold immediately after resistance exercise, whereas 4E-BP1 phosphorylation was reduced to 27 ± 6% of preexercise values. Phosphorylation of S6K1 at Thr421/Ser424 was increased 2- to 2.5-fold during recovery but did not induce a significant change in S6 phosphorylation. Phosphorylation of S6K1 was more pronounced in the type II vs. type I muscle fibers. Before exercise, phosphorylated S6K1 was predominantly located in the nuclei. After 2 h of postexercise recovery, phospho-S6K1 was primarily located in the cytosol of type II muscle fibers. We conclude that resistance exercise effectively increases the phosphorylation of S6K1 on Thr421/Ser424, which is not associated with a substantial increase in S6 phosphorylation in a fasted state.

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BACKGROUND: The association between vascular disease and elevated plasma total homocysteine (tHcy) concentrations is caused, in part, by inadequate intakes of dietary folate. Increasing folate intake either through supplements or foods naturally rich in folates has been shown to decrease tHcy concentrations. OBJECTIVE: The aim of this study was to determine whether a similar reduction in tHcy was possible in free-living persons receiving dietary counseling. DESIGN: The study included a 4-wk placebo-controlled dietary intervention trial in which participants consumed either unfortified breakfast cereal (control group) or an extra 350 micro g folate derived from food/d (dietary group). Serum folate and tHcy concentrations in both groups were measured before and after the intervention period, and the concentrations in the dietary group were also measured 17 wk after the intervention period. RESULTS: During the 4-wk intervention, mean dietary folate intake in the dietary group increased from 263 (95% CI: 225, 307) to 618 micro g/d (535, 714), resulting in a mean increase in serum folate of 37% (15%, 63%) and a decrease in tHcy from 12.0 (10.9, 13.3) to 11.3 micro mol/L (10.2, 12.5). A further decrease in tHcy occurred in the dietary group during follow-up, with a final tHcy concentration of 9.7 micro mol/L (8.8, 10.8). CONCLUSIONS: Increasing natural folate intake improved folate status and decreased tHcy concentrations to an extent that may significantly reduce the risk of vascular disease. Dietary modification may have advantages over folic acid fortification because the altered food-consumption patterns lead to increased intakes of several vitamins and minerals and decreased intakes of saturated fatty acids.