81 resultados para 13077-021
Resumo:
The H2PtCl6 catalysed hydrosilylation of the terpenes (+)-α-fenchene (XI), (−)-2-methylene bornane (XII), (+)-camphene (XIII) and (−)-3-methylene fenchane (XIV) using HSiMe2Cl or HSiMeCl2 proceeds with high regioselectively and in some cases, with high diastereoselectivity. KF-assisted oxidation of the hydrosilylation products gives predominately endo-terpene alcohols. The alcohols have inverted endo/exo ratios to those formed by oxidative hydroboration. Reaction of XIV with HSiMe2Cl or HSiMeCl2 is accompanied by a clean rearrangement of the isocamphane skeleton into (+)-2-methylene bornane (XII) prior to hydrosilylation.
The hydrosilylation of α-fenchene, 2-methylene bornane, camphene and 3-methylene fenchane with chlorosilanes HSiMenCln − 2 (n=0–2) occurred with varying degrees of diastereoselectivity providing anti-Markovnikov product mixtures, in which the endo-isomers dominate over the exo-isomers. These mixtures were oxidized to give the corresponding terpene alcohols. 3-Methylene fenchane undergoes a rearrangement into 2-methylene bornane prior to hydrosilylation.
Resumo:
The limits of detection (3s) for ascorbic acid were 5×10−8 M with acidic potassium permanganate using both flow injection analysis (FIA) and sequential injection analysis (SIA) whereas the soluble manganese(IV) afforded 1×10−8 M and 5×10−9 M for FIA and SIA, respectively. Determinations of ascorbic acid in Vitamin C tablets were achieved with minimal sample pretreatment using a standard additions calibration and gave good agreement with those of iodimetric titration.
Resumo:
Aims: To evaluate the efficacy of interventions to promote a healthy diet and physical activity in people with impaired glucose tolerance (IGT). Methods: A randomised controlled trial in Newcastle upon Tyne, UK, 1995–98. Participants included 67 adults (38 men; 29 women) aged 24–75 years with IGT. The intervention consisted of regular diet and physical activity counselling based on the stages of change model. Main outcome measures were changes between baseline and 6 months in nutrient intake; physical activity; anthropometric and physiological measurements including serum lipids; glucose tolerance; insulin sensitivity. Results: The difference in change in total fat consumption was significant between intervention and control groups (difference −21.8 (95% confidence interval (CI) −37.8 to −5.8) g/day, P=0.008). A significantly larger proportion of intervention participants reported taking up vigorous activity than controls (difference 30.1, (95% CI 4.3–52.7)%, P=0.021). The change in body mass index was significantly different between groups (difference −0.95 (95% CI −1.5 to −0.4) kg/m2, P=0.001). There was no significant difference in change in mean 2-h plasma glucose between groups (difference −0.19 (95% CI −1.1 to 0.71) mmol/l, NS) or in serum cholesterol (difference 0.02 (95% CI −0.26 to 0.31) mmol/l, NS). The difference in change in fasting serum insulin between groups was significant (difference −3.4 (95% CI −5.8 to −1.1) mU/l, P=0.005). Conclusions: After 6 months of intensive lifestyle intervention in participants with IGT, there were changes in diet and physical activity, some cardiovascular risk factors and insulin sensitivity, but not glucose tolerance. Further follow-up is in progress to investigate whether these changes are sustained or augmented over 2 years.
Resumo:
Renewable energy advocates often invoke the goal of sustainability in order to promote their cause. Most people agree that the energy supply for a sustainable world should be based on safe, clean and renewable forms of energy. However, sustainability is a much over-used word to the point where it has become almost meaningless. This paper argues that we need to reaffirm the meaning of sustainability and use its defining principles to guide our advocacy and practice. If we ignore these principles, we run the danger of generating unrealistic expectations and mistrust, and becoming involved in practice that is questionable from a sustainability perspective. On the other hand, if we use the principles of sustainability to guide our practice and advocacy, our goals will be more achievable, our credibility will increase and our practice will become more ethical. This paper uses one model of sustainability to evaluate examples of renewable energy advocacy and practice.
Resumo:
The replacement of fish oil with vegetable based oils is a strategy which is increasingly being adopted by the aquafeed industry as an essential component to reduce the reliance on a limited supply of a natural resource, which in turn also provides cost benefits. The aim of the present investigation was to evaluate the lipid and fatty acid digestibility of a mix blend vegetable oil in juvenile Murray cod; an emerging species of increasing interest in the Australian aquaculture sector. Five semi purified experimental diets were formulated with 17% lipid originating from fish oil (FO) which was substituted in 25% increments by blended vegetable oil (VO), formulated using olive oil (12%), palm oil (43%) and linseed oil (45%) to match the major fatty acid classes of the FO.
Significant differences between the dietary treatments with regard to the lipid and individual fatty acid digestibility were recorded. This study clearly demonstrated that in Murray cod fatty acid digestibility decreases with chain length, and inversely increases relative to the degree of unsaturation. The combination of chain length, degree of unsaturation and the melting point of individual fatty acids resulted in the digestibility of PUFA > MUFA > SFA and short chain > longer chain fatty acids. Therefore, the inclusion of a mixed blend vegetable oil resulted in significantly reduced lipid digestibility in juvenile Murray cod.
Resumo:
Mesostructurally ordered inorganic–organic hybrid composite materials were successfully synthesized by utilizing a low-molecular-weight amphiphilic polyethylene-block-poly(ethylene oxide) (PE–PEO) diblock copolymer as the directing agent. The hybrid composites were formed via the sol–gel reaction of inorganic precursor tetraethoxysilane (TEOS) in an acidic ethanol/water solution with various amounts of PE–PEO. In these composite materials, the hydrophobic PE block of the PE–PEO copolymer forms separate microphase on the nanoscales within the rigid matrix of silica network. The crystallization of the PE block is strictly restricted within the microphase by the rigid silica matrix and takes place through homogeneous nucleation under the nanoscale confinement environment.
Resumo:
Copper is essential for human health and copper imbalance is a key factor in the aetiology and pathology of several neurodegenerative diseases. The copper-transporting P-type ATPases, ATP7A and ATP7B are key molecules required for the regulation and maintenance of mammalian copper homeostasis. Their absence or malfunction leads to the genetically inherited disorders, Menkes and Wilson diseases, respectively. These proteins have a dual role in cells, namely to provide copper to essential cuproenzymes and to mediate the excretion of excess intracellular copper. A unique feature of ATP7A and ATP7B that is integral to these functions is their ability to sense and respond to intracellular copper levels, the latter manifested through their copper-regulated trafficking from the transGolgi network to the appropriate cellular membrane domain (basolateral or apical, respectively) to eliminate excess copper from the cell. Research over the last decade has yielded significant insight into the enzymatic properties and cell biology of the copper-ATPases. With recent advances in elucidating their localization and trafficking in human and animal tissues in response to physiological stimuli, we are progressing rapidly towards an integrated understanding of their physiological significance at the level of the whole animal. This knowledge in turn is helping to clarify the biochemical and cellular basis not only for the phenotypes conferred by individual Menkes and Wilson disease patient mutations, but also for the clinical variability of phenotypes associated with each of these diseases. Importantly, this information is also providing a rational basis for the applicability and appropriateness of certain diagnostic markers and therapeutic regimes. This overview will provide an update on the current state of our understanding of the localization and trafficking properties of the copper-ATPases in cells and tissues, the molecular signals and posttranslational interactions that govern their trafficking activities, and the cellular basis for the clinical phenotypes associated with disease-causing mutations.
Resumo:
This paper places the ‘V’ factor at the epicentre of meaningful and productive living, learning and leadership endeavour. It explores the authors’ reflections upon their own professional experiences, research studies and review of the literature as they work towards establishing ‘working with’ leadership practices appropriate for a knowledge era. This paper also reports on Nanschild’s preliminary PhD research findings of “A Values-Based Approach to Leadership Development: Implications for Organisational Change”.
Resumo:
Bis(p-substituted benzoylmethyl)tellurium dibromides, (p-YC6H4COCH2)2TeBr2, (y=H (1a), Me (1b), MeO (1c)) can be prepared
either by direct insertion of elemental Te across CRf-Br bonds (where CRf refers to α-carbon of a functionalized organic moiety) or by the oxidative addition of bromine to (p-YC6H4COCH2)2Te (y = H (2a), Me (2b), MeO (2c)). Bis(p-substituted benzoylmethyl)tellurium dichlorides, (p-YC6H4COCH2)2TeCh (y = H (3a), Me (3b), MeO (3c)), are prepared by the reaction of the bis(p-substituted benzoylmethyl)tellurides 2a--c with S02Cl2, whereas the corresponding diiodides (p-YC6H4COCH2)2Teh (y = H
(4a), Me (4b), MeO (4c)) can be obtained by the metathetical reaction of la--c with KI, or alternatively, by the oxidative addition of
iodine to 2a--c. The reaction of 2a--c with allyl bromide affords the diorganotellurium dibrornides la--c, rather than the expected
triorganotelluronium bromides. Compounds 1-4 were characterized by elemental analyses, IR spectroscopy, 1H, l3C and 125Te
NMR spectroscopy (solution and solid-state) and in case of Ie also by X-ray crystallography. (p-MeOC6H4COCH2)2TeBr2 (1c) provides, a rare example, among organotellurium compounds, of a supramolecular architecture, where C-H-O hydrogen bonds appear to be the non-covalent intermolecular associative force that dominates the crystal packing.
Resumo:
Background : Physical inactivity and insufficient fruit and vegetable consumption are key risk factors for obesity and noncommunicable diseases. Weight perceptions may affect physical activity and diet behaviors. We report current prevalence estimates of Australian adults meeting recommended levels of leisure-time physical activity (LTPA) (150 min/week or more of at least moderate-intensity physical activity (including walking) on 5 days/week) and fruit (2 servings/day) and vegetable (5 servings/day) consumption for health benefits, by weight status and perceptions.
Methods : We conducted a cross-sectional survey analysis of data for 16 314 adults from the Australian National Health Survey 2004–2005. All variables were collected by self-report. Weighted estimates were age- and gender-specific, and data were analyzed using logistic regression with acceptable weight referent categories, adjusting for covariates.
Results : Among acceptable, overweight and obese adults, the prevalence of LTPA was 26.8, 26.1 and 19.3% for men, and 27.7, 23.7 and 19.7% for women, respectively. Approximately 55 and 15% of adults consumed sufficient fruit servings/day and vegetable servings/day, respectively, and less than 5% of adults met combined LTPA and diet guidelines. Overweight decreased the odds ratio for LTPA among women but not men, and obesity decreased the odds ratio for LTPA among both men and women. Overweight perception conferred odds ratios of 0.83 (95% CI 0.70–0.97, P=0.021) for overweight men, and of 0.74 (95% CI 0.62–0.88, P=0.001) and 0.69 (95% CI 0.59–0.80, P<0.001) for obese men and women, respectively; for LTPA, whereas no significant associations were found for acceptable weight perception. No consistent associations between weight status or perceptions and diet behaviors were found.
Conclusions : Overweight perception may be another barrier to physical activity participation among men and women with excess body weight. Public health strategies might need to focus on overcoming weight perception as well as weight status barriers to adopting healthy physical activity behaviors.
Resumo:
The importance of stress as a factor in influencing life history strategies has received considerable attention in recent years, because it appears to have a substantial impact on an individual's behaviour and physiology. Birds respond to environmental and social stressors by the production of corticosterone, a glucocorticoid hormone released by the adrenal gland. In this experiment, we tested whether female zebra finches preferred males selected to produce low or high peak levels of circulating plasma corticosterone. Plasma corticosterone and testosterone levels of the males were recorded, as were morphometric measurements and perch activity. Spectrophotometric measurements were also taken from several putatively sexually selected regions of the males. The females preferred the males from the low corticosterone lines to the high corticosterone males. In addition to, and consistent with this effect, females preferred males with the lowest corticosterone titres. Male activity, testosterone level, body size and mass had no effect on female preference. Leg and beak brightness were important, however, as were the brightness and chromaticity of the male cheek patch. These results are discussed in relation to contemporary hypotheses in sexual selection, particularly in the context of stress-mediated signalling.
Resumo:
Objective
The use of then-test (retrospective pre-test) scores has frequently been proposed as a solution to potential confounding of change scores because of response shift, as it is assumed that then-test and post-test responses are provided from the same perspective. However, this assumption has not been formally tested using robust quantitative methods. The aim of this study was to compare the psychometric performance of then-test/post-test with traditional pre-test/post-test data and assessing whether the resulting data structures support the application of the then-test for evaluations of chronic disease self-management interventions.
Study Design and Setting
Pre-test, post-test, and then-test data were collected from 314 participants of self-management courses using the Health Education Impact Questionnaire (heiQ). The derived change scores (pre-test/post-test; then-test/post-test) were examined for their psychometric performance using tests of measurement invariance.
Results
Few questionnaire items were noninvariant across pre-test/post-test, with four items identified and requiring removal to enable an unbiased comparison of factor means. In contrast, 12 items were identified and required removal in then-test/post-test data to avoid biased change score estimates.
Conclusion
Traditional pre-test/post-test data appear to be robust with little indication of response shift. In contrast, the weaker psychometric performance of then-test/post-test data suggests psychometric flaws that may be the result of implicit theory of change, social desirability, and recall bias.
Resumo:
Background : Female gymnasts frequently present with overt signs of hypoestrogenism, such as late menarche or menstrual dysfunction. The objective was to investigate the impact of history of amenorrhoea on the exercise-induced skeletal benefits in bone geometry and volumetric density in retired elite gymnasts.
Subjects and methods
24 retired artistic gymnasts, aged 17–36 years, who had been training for at least 15 h/week at the peak of their career and had been retired for 3–18 years were recruited. They had not been engaged in more than 2 h/week of regular physical activity since retirement. Former gymnasts who reported history of amenorrhoea (‘AME’, n = 12: either primary or secondary amenorrhoea) were compared with former gymnasts (‘NO-AME’, n = 12) and controls (‘C’, n = 26) who did not report history of amenorrhoea. Bone mineral content (BMC), total bone area (ToA) and total volumetric density (ToD) were measured by pQCT at the radius and tibia (4% and 66%). Trabecular volumetric density (TrD) and bone strength index (BSI) were measured at the 4% sites. Cortical area (CoA), cortical thickness (CoTh), medullary area (MedA), cortical volumetric density (CoD), stress–strain index (SSI) and muscle and fat area were measured at the 66% sites. Spinal BMC, areal BMD and bone mineral apparent density (BMAD) were measured by DXA.
Results
Menarcheal age was delayed in AME when compared to NO-AME (16.4 ± 0.5 years vs. 13.3 ± 0.4 years, p < 0.001). No differences were detected between AME and C for height-adjusted spinal BMC, aBMD and BMAD, TrD and BSI at the distal radius and tibia, CoA at the proximal radius, whereas these parameters were greater in NO-AME than C (p < 0.05–0.005). AME had lower TrD and BSI at the distal radius, and lower spinal BMAD than NO-AME (p < 0.05) but they had greater ToA at the distal radius (p < 0.05).
Conclusion
Greater spinal BMC, aBMD and BMAD as well as trabecular volumetric density and bone strength in the peripheral skeleton were found in former gymnasts without a history of menstrual dysfunction but not in those who reported either primary or secondary amenorrhoea. History of amenorrhoea may have compromised some of the skeletal benefits associated with high-impact gymnastics training.
Resumo:
In a cross-sectional study, we determined whether results from the Mini Nutritional Assessment (MNA), Geriatric Depression Scale (GDS), and Katz Activities of Daily Living (ADL), were associated with nutritional status and mobility in long-term care residents. One hundred and fifteen study participants (mean [SD] age: 80.2 [10.6]) provided informed consent. Fifty eight percent (n = 66) responded to all three questionnaires: 12 were assessed as malnourished (MNA < 17) and 28 were depressed (GDS ≥ 6). Higher levels of depression were associated with lower serum zinc (n = 71, r = -.356, p = .001) and associated with a slower Timed Up and Go test (TUG, n = 38, r = .301, p = .030). MNA was also associated with serum zinc (n = 44, r = .307, P = .021). Non responders to questionnaires (n = 36) had a lower BMI (mean difference: -2.5 ± 1.0 kg/m2, p = .013) and serum 25(OH)D (-8.7 ± 3.8 nmol/l, p = .023) vs. responders. The GDS, in addition to the MNA, is useful in identifying poor nutritional status in residential care. Intervention programs that target depression and poor nutritional status could potentially improve overall quality of life, but it is not clear if depression is leading to poor nutritional status or if poor nutrition is leading to depression.
Resumo:
A distinct mesotexture seen in a nanocrystalline Ni–20Fe electrodeposit is described. The texture is characterized by a ⟨0 0 1⟩fibre axis perpendicular to the local curvature of the nodule growth surface. Each nodule contains of the order of 108 grains over its growth interface. The texture shows some similarity to traditional cobblestone patterns. Similar forms of mesotextures are likely to be ubiquitous in nanocrystalline electrodeposits and can be expected to affect the homogeneity and, possibly, anisotropy of the mechanical response.