358 resultados para Iron age


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The galvanic replacement reaction has received considerable interest due to the creation of novel bimetallic nanomaterials that minimise the use of expensive metals while maintaining enhanced electrocatalytic properties for certain reactions. In this work we investigate the galvanic replacement of electrochemically synthesised iron nanocubes on glassy carbon, with gold and palladium. The resultant nanomaterials demonstrate quite a difference in morphology; the original cuboid like template is maintained in the case of gold but destroyed when palladium is used. The electrochemical and electrocatalytic behaviours of these materials are reported for reactions such as methanol oxidation, hydrogen evolution and oxygen reduction.

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Background Australian Indigenous children are the only population worldwide to receive the 7-valent pneumococcal conjugate vaccine (7vPCV) at 2, 4, and 6 months of age and the 23-valent pneumococcal polysaccharide vaccine (23vPPV) at 18 months of age. We evaluated this program's effectiveness in reducing the risk of hospitalization for acute lower respiratory tract infection (ALRI) in Northern Territory (NT) Indigenous children aged 5-23 months. Methods We conducted a retrospective cohort study involving all NT Indigenous children born from 1 April 2000 through 31 October 2004. Person-time at-risk after 0, 1, 2, and 3 doses of 7vPCV and after 0 and 1 dose of 23vPPV and the number of ALRI following each dose were used to calculate dose-specific rates of ALRI for children 5-23 months of age. Rates were compared using Cox proportional hazards models, with the number of doses of each vaccine serving as time-dependent covariates. Results There were 5482 children and 8315 child-years at risk, with 2174 episodes of ALRI requiring hospitalization (overall incidence, 261 episodes per 1000 child-years at risk). Elevated risk of ALRI requiring hospitalization was observed after each dose of the 7vPCV vaccine, compared with that for children who received no doses, and an even greater elevation in risk was observed after each dose of the 23vPPV ( adjusted hazard ratio [HR] vs no dose, 1.39; 95% confidence interval [CI], 1.12-1.71;). Risk was highest among children Pp. 002 vaccinated with the 23vPPV who had received < 3 doses of the 7vPCV (adjusted HR, 1.81; 95% CI, 1.32-2.48). Conclusions Our results suggest an increased risk of ALRI requiring hospitalization after pneumococcal vaccination, particularly after receipt of the 23vPPV booster. The use of the 23vPPV booster should be reevaluated.

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Purpose: The objective of the study was to assess the bioequivalence of two tablet formulations of capecitabine and to explore the effect of age, gender, body surface area and creatinine clearance on the systemic exposure to capecitabine and its metabolites. Methods: The study was designed as an open, randomized two-way crossover trial. A single oral dose of 2000 mg capecitabine was administered on two separate days to 25 patients with solid tumors. On one day, the patients received four 500-mg tablets of formulation B (test formulation) and on the other day, four 500-mg tablets of formulation A (reference formulation). The washout period between the two administrations was between 2 and 8 days. After each administration, serial blood and urine samples were collected for up to 12 and 24 h, respectively. Unchanged capecitabine and its metabolites were determined in plasma using LC/MS-MS and in urine by NMRS. Results: Based on the primary pharmacokinetic parameter, AUC(0-∞) of 5'-DFUR, equivalence was concluded for the two formulations, since the 90% confidence interval of the estimate of formulation B relative to formulation A of 97% to 107% was within the acceptance region 80% to 125%. There was no clinically significant difference between the t(max) for the two formulations (median 2.1 versus 2.0 h). The estimate for C(max) was 111% for formulation B compared to formulation A and the 90% confidence interval of 95% to 136% was within the reference region 70% to 143%. Overall, these results suggest no relevant difference between the two formulations regarding the extent to which 5'-DFUR reached the systemic circulation and the rate at which 5'-DFUR appeared in the systemic circulation. The overall urinary excretions were 86.0% and 86.5% of the dose, respectively, and the proportion recovered as each metabolite was similar for the two formulations. The majority of the dose was excreted as FBAL (61.5% and 60.3%), all other chemical species making a minor contribution. Univariate and multivariate regression analysis to explore the influence of age, gender, body surface area and creatinine clearance on the log-transformed pharmacokinetic parameters AUC(0-∞) and C(max) of capecitabine and its metabolites revealed no clinically significant effects. The only statistically significant results were obtained for AUC(0-∞) and C(max) of intact drug and for C(max) of FBAL, which were higher in females than in males. Conclusion: The bioavailability of 5'-DFUR in the systemic circulation was practically identical after administration of the two tablet formulations. Therefore, the two formulations can be regarded as bioequivalent. The variables investigated (age, gender, body surface area, and creatinine clearance) had no clinically significant effect on the pharmacokinetics of capecitabine or its metabolites.

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Lens average and equivalent refractive indices are required for purposes such as lens thickness estimation and optical modeling. We modeled the refractive index gradient as a power function of the normalized distance from lens center. Average index along the lens axis was estimated by integration. Equivalent index was estimated by raytracing through a model eye to establish ocular refraction, and then backward raytracing to determine the constant refractive index yielding the same refraction. Assuming center and edge indices remained constant with age, at 1.415 and 1.37 respectively, average axial refractive index increased (1.408 to 1.411) and equivalent index decreased (1.425 to 1.420) with age increase from 20 to 70 years. These values agree well with experimental estimates based on different techniques, although the latter show considerable scatter. The simple model of index gradient gives reasonable estimates of average and equivalent lens indices, although refinements in modeling and measurements are required.

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The aim of this study was to examine whether maternal-report of child eating behaviour at two years predicted self-regulation of energy intake and weight status at four years. Using an ‘eating in the absence of hunger’ paradigm, children’s energy intake (kJ) from a semi-standardized lunch meal and a standardized selection of snacks were measured. Participants were 37 mother-child dyads (16 boys, Median child age = 4.4 years, Inter-quartile range = 3.7-4.5 years) recruited from an existing longitudinal study (NOURISH randomised controlled trial). All participants were tested in their own home. Details of maternal characteristics, child eating behaviours (at age two years) reported by mothers on a validated questionnaire, and measured child height and weight (at age 3.5-4 years) were sourced from existing NOURISH trial data. Correlation and partial correlation analyses were used to examine longitudinal relationships. Satiety responsiveness and Slowness in eating were inversely associated with energy intake of the lunch meal (partial r = -.40, p =.023, and partial r = -.40, p = .023) and the former was also negatively associated with BMI-for-age Z score (partial r = -.42, p = .015). Food responsiveness and Enjoyment of food were not related to energy intake or BMI Z score. None of the eating behaviours were significantly associated with energy intake of the snacks (i.e., eating in the absence of hunger). The small and predominantly ‘healthy weight’ sample of children may have limited the ability to detect some hypothesized effects. Nevertheless, the study provides evidence for the predictive validity of two eating behaviours and future research with a larger and more diverse sample should be able to better evaluate the predictive validity of other children’s early eating behaviour styles.

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Drink driving remains a major cause of serious and fatal car crashes in Australia and internationally. While this problem is more prevalent among male drivers, the rates of female intoxicated drivers have increased steadily over the past decades in many motorised countries. A combination of police enforcement, media awareness campaigns, and community initiatives has played a key role in reducing incidents of illegal drink driving by targeting public drink driving attitudes. However, important cultural differences in regards to the tolerance towards drink driving have been noted. While many countries, including Australia, have a legal Blood Alcohol Concentration (BAC) limit of .05 or higher, some countries have moved towards a zero –or low tolerance approach to drink driving; several European countries, including Sweden, Hungary, Slovakia, and Estonia currently enforce .00 or .02 BAC limits.

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Maternal depression is a known risk factor for poor outcomes for children. Pathways to these poor outcomes relate to reduced maternal responsiveness or sensitivity to the child. Impaired responsiveness potentially impacts the feeding relationship and thus may be a risk factor for inappropriate feeding practices. The aim of this study was to examine the longitudinal relationships between self-reported maternal post-natal depressive symptoms at child age 4 months and feeding practices at child age 2 years in a community sample. Participants were Australian first-time mothers allocated to the control group of the NOURISH randomized controlled trial when infants were 4 months old. Complete data from 211 mothers (of 346 allocated) followed up when their children were 2 years of age (51% girls) were available for analysis. The relationship between Edinburgh Postnatal Depression Scale (EPDS) score (child age 4 months) and child feeding practices (child age 2 years) was tested using hierarchical linear regression analysis adjusted for maternal and child characteristics. Higher EPDS score was associated with less responsive feeding practices at child age 2 years: greater pressure [β = 0.18, 95% confidence interval (CI): 0.04–0.32, P = 0.01], restriction (β = 0.14, 95% CI: 0.001–0.28, P = 0.05), instrumental (β = 0.14, 95% CI: 0.005–0.27, P = 0.04) and emotional (β = 0.15, 95% CI: 0.01–0.29, P = 0.03) feeding practices (ΔR2 values: 0.02–0.03, P < 0.05). This study provides evidence for the proposed link between maternal post-natal depressive symptoms and lower responsiveness in child feeding. These findings suggest that the provision of support to mothers experiencing some levels of depressive symptomatology in the early post-natal period may improve responsiveness in the child feeding relationship.

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Age trajectories for personality traits are known to be similar across cultures. To address whether stereotypes of age groups reflect these age-related changes in personality, we asked participants in 26 countries (N = 3,323) to rate typical adolescents, adults, and old persons in their own country. Raters across nations tended to share similar beliefs about different age groups; adolescents were seen as impulsive, rebellious, undisciplined, preferring excitement and novelty, whereas old people were consistently considered lower on impulsivity, activity, antagonism, and Openness. These consensual age group stereotypes correlated strongly with published age differences on the five major dimensions of personality and most of 30 specific traits, using as criteria of accuracy both self-reports and observer ratings, different survey methodologies, and data from up to 50 nations. However, personal stereotypes were considerably less accurate, and consensual stereotypes tended to exaggerate differences across age groups.

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A novel composite material based on deposition of nanosized zero-valent iron (nZVI) particles on acid-leached diatomite was synthesised for the removal of a chlorinated contaminant in water. The nZVI /diatomite composites were characterized by X-ray diffraction, scanning electron microscopy, elemental analysis, transmission electron microscopy and X-ray photoelectron spectroscopy. Compared with the pure nZVI particles, better dispersion of nZVI particles on the surface or inside the pores of diatom shells was observed. The herbicide simazine was selected as the model chlorinated contaminant and the removal efficiency by nZVI /diatomite composite was compared with that of the pristine nZVI and commercial iron powder. It was found that the diatomite supported nZVI composite material prepared by centrifugation exhibits relatively better efficient activity in decomposition of simazine than commercial Fe, lab synthesized nZVI and composite material prepared via rotary evaporation, and the optimum experimental conditions were obtained based on a series of batch experiments. This study on immobilizing nZVI particles onto diatomite opens a new avenue for the practical application of nZVI and the diatomite-supported nanosized zero-valent iron composite materials have potential applications in environmental remediation.

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The thick piles of late-Archean volcaniclastic sedimentary successions that overlie the voluminous greenstone units of the eastern Yilgarn Craton, Western Australia, record the important transition from the cessation in mafic-ultramafic volcanism to cratonisation between about 2690 and 2655 Ma. Unfortunately, an inability to clearly subdivide the superficially similar sedimentary successions and correlate them between the various geological terranes and domains of the eastern Yilgarn Craton has led to uncertainty about the timing and nature of the region's palaeogeographic and palaeotectonic evolution. Here, we present the results of some 2025 U–Pb laser-ablation-ICP-MS analyses and 323 Sensitive High-Resolution Ion Microprobe (SHRIMP) analyses of detrital zircons from 14 late-Archean felsic clastic successions of the eastern Yilgarn Craton, which have enabled correlation of clastic successions. The results of our data, together with those compiled from previous studies, show that the post-greenstone sedimentary successions include two major cycles that both commenced with voluminous pyroclastic volcanism and ended with widespread exhumation and erosion associated with granite emplacement. Cycle One commences with an influx of rapidly reworked feldspar-rich pyroclastic debris. These units, here-named the Early Black Flag Group, are dominated by a single population of detrital zircons with an average age of 2690–2680 Ma. Thick (up to 2 km) dolerite bodies, such as the Golden Mile Dolerite, intrude the upper parts of the Early Black Flag Group at about 2680 Ma. Incipient development of large granite domes during Cycle One created extensional basins predominantly near their southeastern and northwestern margins (e.g., St Ives, Wallaby, Kanowna Belle and Agnew), into which the Early Black Flag Group and overlying coarse mafic conglomerate facies of the Late Black Flag Group were deposited. The clast compositions and detrital-zircon ages of the late Black Flag Group detritus match closely the nearby and/or stratigraphically underlying successions, thus suggesting relatively local provenance. Cycle Two involved a similar progression to that observed in Cycle One, but the age and composition of the detritus were notably different. Deposition of rapidly reworked quartz-rich pyroclastic deposits dominated by a single detrital-zircon age population of 2670–2660 Ma heralded the beginning of Cycle Two. These coarse-grained quartz-rich units, are name here the Early Merougil Group. The mean ages of the detrital zircons from the Early Merougil Group match closely the age of the peak in high-Ca (quartz-rich) granite magmatism in the Yilgarn Craton and thus probably represent the surface expression of the same event. Successions of the Late Merougil Group are dominated by coarse felsic conglomerate with abundant volcanic quartz. Although the detrital zircons in these successions have a broad spread of age, the principal sub-populations have ages of about 2665 Ma and thus match closely those of the Early Merougil Group. These successions occur most commonly at the northwestern and southeastern margins of the granite batholiths and thus are interpreted to represent resedimented units dominted by the stratigraphically underlying packages of the Early Merougil Group. The Kurrawang Group is the youngest sedimentary units identified in this study and is dominated by polymictic conglomerate with clasts of banded iron formation (BIF), granite and quartzite near the base and quartz-rich sandstone units containing detrital zircons aged up to 3500 Ma near the top. These units record provenance from deeper and/or more-distal sources. We suggest here that the principal driver for the major episodes of volcanism, sedimentation and deformation associated with basin development was the progressive emplacement of large granite batholiths. This interpretation has important implication for palaeogeographic and palaeotectonic evolution of all late-Archean terranes around the world.

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Bisphenol A (BPA or 4,4’-(propane-2,2-diyl)diphenol) is a chemical intermediate in the production of polycarbonate and epoxy resins, and used in a wide range of applications. BPA has attracted significant attention in the past decade due to its frequency of detection in human populations worldwide, demonstrated animal toxicity and potential impact on human health, particularly during critical periods of development. The aim of this study was to perform a preliminary assessment of age-related trends in urinary concentration and to estimate daily excretion of BPA in Australian children (aged (>0 – <5 years) and adults (≥15 – <75 years). This was achieved using 79 samples pooled by age and gender, created from 868 individual samples of convenience collected as part of routine, community-based pathology testing. Total BPA was analyzed using online-SPE-LC-MS/MS and detected in all samples with a range of 0.65 – 265 ng/ml. No significant differences were observed between males and females. A urine flow model was constructed from published values and used to provide an estimate of daily excretion per unit bodyweight for each pooled sample. The daily excretion estimates ranged from 26.2 – 18200 ng/kg-d for children; and 20.1 – 165 ng/kg-d for adults. Urinary concentrations and estimated excretion rates were inversely associated with age, and estimated daily excretion rates in infants and young children were significantly higher than in adults (geometric mean: 107 and 47.0 ng/kg-d, respectively). Higher excretion of BPA in children may be explained by their higher food consumption relative to body weight compared to adults and adolescents, and may also reflect alternative exposure pathways and sources. Keywords: bisphenol A, biomonitoring, children, urine flow, Australia

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This article explores the contradictory ways in which adolescents just under the age of consent are represented in illegal sexual relations with both men and women who are over the age of consent. We are specifically interested in the ways in which the gender of the adolescent and the adult affect public perceptions, legal responses and perceptions of harm of sexual relations. We argue that the development of an indiscriminate legal and policy narrative of child abuse which increasingly includes all aspects of adolescent sexuality, ‘erases’ adolescent subjectivity. By exploring the nuanced ways in which the historical construction of childhood as sexually innocent intersects with current cultural scripts of femininity and masculinity, this article hopes to add to the small but growing literature on the issue of sexual consent, sexual ethics and sexual citizenship for young people.

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This is an invited public lecture. The talk will cover how the music industry has changed due to digital technologies. During the talk I will look at how the changing balance between live music, music licensing and recorded music. I will also discuss online music subscription services and whether they might be a future for music distribution in China and elsewhere in the world. It will also look at how music artists and composers are affected by this change.