Deactivation and regeneration of oxygen reduction reactivity on double perovskite Ba2Bi0.1Sc0.2Co1.7O6−x cathode for intermediate-temperature solid oxide fuel cells

in situ high-temperature X-ray diffraction and thermal gravimetric- differential thermal analysis on room-temperature powder, as well as X-ray diffraction, Raman spectroscopy, and transmission electron microscopy on quenched powder, were applied to study crystal structure and phase transformations in Ba₂Bi_0.1Sc_0.2Co _1.7O_6-x (BBSC). Heating BBSC in air to over 800 °C produces a pure cubic phase with space group Fm3m (no. 225), and cooling down below 800 °C leads to a mixture of three noncubic phases including an unknown phase between 200 and 650 °C, a 2H hexagonal BaCoO3 with space group P63/mmc (no. 194) between 600 and 800 °C, and an intermediate phase at 800 °C. These three phases exist concurrently with the major cubic phase. The weight gain and loss between 300 and 900 °C suggest the occurrence of cobalt reduction, oxidation, and disproportion reactions with dominant reduction reaction at above 600 °C. The thermal expansion of BBSC was also examined by dilatometry. BBSC has a highly temperature-dependent thermal expansion coefficient which relates well with its structure evolution. Furthermore, the oxygen reduction reaction (ORR) of BBSC was probed by symmetrical cell and three-electrode configurations. The presence of hexagonal phase at 700 °C rarely affects the ORR performance of BBSC as evidenced by a slight increase of its area-specific resistance (ASR) value following 48 h of testing in this three-electrode configuration. This observation is in contrast to the commonly held point of view that noncubic phase deteriorates performance of perovskite compounds (especially in oxygen transport applications). Moreover, cathodic polarization treatment, for example, current discharge from BBSC (tested in three-electrode configuration), can be utilized to recover the original ORR performance. The cubic structure seems to be retained on the cathodic polarization - the normal cathode operating mode in fuel cells. Stable 72-h performance of BBSC in cathodic polarization mode further confirms that despite the presence of phase impurities, BBSC still demonstrates good performance between 500 and 700 °C, the desired intermediate operating temperature in solid oxide fuel cells.

Chronic stress alters the density and morphology of microglia in a subset of stress-responsive brain regions

The current study, in parallel experiments, evaluated the impact of chronic psychological stress on physiological and behavioural measures, and on the activation status of microglia in 15 stress-responsive brain regions. Rats were subjected, for 14 days, to two 30 min sessions of restraint per day, applied at random times each day. In one experiment the effects of stress on sucrose preference, weight gain, core body temperature, and struggling behaviour during restraint, were determined. In the second experiment we used immunohistochemistry to investigate stress-induced changes in ionized calcium-binding adaptor molecule-1 (Iba1), a marker constitutively expressed by microglia, and major histocompatibility complex-II (MHC-II), a marker often expressed on activated microglia, in a total of 15 stress-responsive nuclei. We also investigated cellular proliferation in these regions using Ki67 immunolabelling, to check for the possibility of microglial proliferation. Collectively, the results we obtained showed that chronic stress induced a significant increase in anhedonia, a decrease in weight gain across the entire observation period, a significant elevation in core body temperature during restraint, and a progressive decrease in struggling behaviour within and over sessions. With regard to microglial activation, chronic stress induced a significant increase in the density of Iba1 immunolabelling (nine of 15 regions) and the number of Iba1-positive cells (eight of 15 regions). Within the regions that exhibited an increased number of Iba1-positive cells after chronic stress, we found no evidence of a between group difference in the number of MHC-II or Ki67 positive cells. In summary, these results clearly demonstrate that chronic stress selectively increases the number of microglia in certain stress-sensitive brain regions, and also causes a marked transition of microglia from a ramified-resting state to a non-resting state. These findings are consistent with the view that microglial activation could play an important role in controlling and/or adapting to stress.

Influences on consumption of soft drinks and fast foods in adolescents

Soft drink and fast food are energy dense foodstuffs that are heavily marketed to adolescents, and are likely to be important in terms of risk of obesity. This study sought to examine the influences on soft drink and fast food consumption among adolescents as part of a cross-sectional survey of 2,719 adolescents (aged 11-16) from 93 randomly selected schools in New South Wales, Australia. Students provided information on soft drink and fast food consumption, and responded to statements examining influences over consumption. Over half of the boys and more than one third of the girls reported drinking soft drink daily, and consumption peaked in Grade 8 students. A quarter of students reported choosing soft drinks instead of water or milk, and around 40% agreed that soft drink was usually available in their homes. Availability in the home and drinking soft drinks with meals was most strongly associated with consumption in all age groups. Fast food consumption was higher among boys than girls in all age groups. Convenience and value for money yielded the strongest associations with fast food
consumption in boys, while preferring fast food to meals at home and preferring to “upsize” meals were most strongly associated with consumption in girls. Interventions to reduce consumption of soft drinks should target availability in both the home and school environment by removing soft drinks and replacing them with more nutritive beverages. Fast food outlets should be encouraged to provide a greater range of healthy and competitively priced options in reasonable portions.

The association between television viewing and preschool child body mass index : a systematic review of english papers published from 1995 to 2010

This paper is a conceptual and methodological review of the literature on the impact of TV on preschoolers' weight status. A systematic search, of papers published between January 1995 and January 2010, identified twenty-six relevant studies. Fifteen of these were cross-sectional in design and eleven adopted a prospective design; a positive association between hours of TV and child adiposity was found in all but three studies. Although assessed in a limited number of studies, diet may mediate the relationship between TV viewing and BMI. Another likely mediator may be the content of TV programs watched; only three studies examined this association and findings were inconsistent. Our review revealed that research examining mediating effects is limited, focusing more on simple cross-sectional or prospective relationships between TV habits and child body mass index. Further investigation of the mechanisms by which TV viewing affects preschool weight gain is needed.

Home and neighbourhood correlates of BMI among children living in socioeconomically disadvantaged neighbourhoods

A detailed understanding of the underlying drivers of obesity-risk behaviours is needed to inform prevention initiatives, particularly for individuals of low socioeconomic position who are at increased risk of unhealthy weight gain. However, few studies have concurrently considered factors in the home and local neighbourhood environments, and little research has examined determinants among children from low socioeconomic backgrounds. The present study examined home, social and neighbourhood correlates of BMI (kg/m2) in children living in disadvantaged neighbourhoods. Cross-sectional data were collected from 491 women with children aged 5–12 years living in forty urban and forty rural socioeconomically disadvantaged areas (suburbs) of Victoria, Australia in 2007 and 2008. Mothers completed questionnaires about the home environment (maternal efficacy, perceived importance/beliefs, rewards, rules and access to equipment), social norms and perceived neighbourhood environment in relation to physical activity, healthy eating and sedentary behaviour. Children's height and weight were measured at school or home. Linear regression analyses controlled for child sex and age. In multivariable analyses, children whose mothers had higher efficacy for them doing physical activity tended to have lower BMI z scores (B = − 0·04, 95 % CI − 0·06, − 0·02), and children who had a television (TV) in their bedroom (B = 0·24, 95 % CI 0·04, 0·44) and whose mothers made greater use of food as a reward for good behaviour (B = 0·05, 95 % CI 0·01, 0·09) tended to have higher BMI z scores. Increasing efficacy among mothers to promote physical activity, limiting use of food as a reward and not placing TV in children's bedrooms may be important targets for future obesity prevention initiatives in disadvantaged communities.

A bi-directional relationship between obesity and health-related quality of life : evidence from the longitudinal AusDiab study

Objective: To assess the prospective relationship between obesity and health-related quality of life, including a novel assessment of the impact of health-related quality of life on weight gain.

Design and setting: Longitudinal, national, population-based Australian Diabetes, Obesity and Lifestyle (AusDiab) study, with surveys conducted in 1999/2000 and 2004/2005.

Participants: A total of 5985 men and women aged 25 years at study entry.

Main outcome measure(s): At both time points, height, weight and waist circumference were measured and self-report data on health-related quality of life from the SF-36 questionnaire were obtained. Cross-sectional and bi-directional, prospective associations between obesity categories and health-related quality of life were assessed.

Results: Higher body mass index (BMI) at baseline was associated with deterioration in health-related quality of life over 5 years for seven of the eight health-related quality of life domains in women (all P0.01, with the exception of mental health, P>0.05), and six out of eight in men (all P<0.05, with the exception of role-emotional, P=0.055, and mental health, P>0.05). Each of the quality-of-life domains related to mental health as well as the mental component summary were inversely associated with BMI change (all P<0.0001 for women and P0.01 for men), with the exception of vitality, which was significant in women only (P=0.008). For the physical domains, change in BMI was inversely associated with baseline general health in women only (P=0.023).

Conclusions: Obesity was associated with a deterioration in health-related quality of life (including both physical and mental health domains) in this cohort of Australian adults followed over 5 years. Health-related quality of life was also a predictor of weight gain over 5 years, indicating a bi-directional association between obesity and health-related quality of life. The identification of those with poor health-related quality of life may be important in assessing the risk of future weight gain, and a focus on health-related quality of life may be beneficial in weight management strategies.

Intergenerational differences in food, physical activity, and body size perceptions among African migrants

We assessed intergenerational differences in food, physical activity, and body size perceptions among refugees and migrants from the Horn of Africa living in Victoria, Australia. We used a qualitative design and obtained data from 48 participants (18 individual interviews; 3 semistructured focus groups). Three major themes emerged: (a) food and physical activity, (b) preference of body size and social expectations, and (c) perceived consequences of various body sizes. For parents, large body size was perceived to equate with being beautiful and wealthy; slimness was associated with chronic illness and poverty. Parents adopted strategies that promoted weight gain in children. These included tailored food practices and restricting children’s involvement in physical activity. For young people, slimness was the ideal body size endorsed by their peers, and they adopted strategies to resist parental pressure to gain weight. Obesity-prevention programs in this subpopulation need to adopt a multigenerational approach.

Predictors of increasing waist circumference in an Australian population

Objective To identify predictors of increasing waist circumference (WC) over a 5-year period in a contemporary population of Australian adults.

Design Longitudinal national cohort of adults participating in the Australian Diabetes, Obesity and Lifestyle Study (AusDiab).

Settings Australian adults in 2000 and 2005.

Subjects A total of 2521 men and 2726 women aged ≥25 years at baseline who participated in AusDiab and provided anthropometric measurements at baseline (1999–2000) and follow-up (2005).

Results A ≥5 % increase of baseline WC occurred in 27 % of men and 38 % of women over the 5-year period. In the multivariate analysis of the total population, there was a higher risk of ≥5 % gain in baseline WC in women, younger people, people with a lower baseline WC, people who never married compared with married/de facto, current smokers compared with never smokers, people with a poorer diet quality and people with a low energy intake. However, there was no significant association with many expected predictors of waist gain such as physical activity. There were some associations between other lifestyle factors and change of WC by sex, age, level of education and across WC categories, but the associations differed across these groups.

Conclusions A ≥5 % increase of baseline WC occurred in a significant proportion of men and women over the 5-year period. Of the behavioural factors, poor diet quality was the key predictor of the ≥5 % increase of baseline WC in this cohort. The findings highlight the need to understand better the causal role of lifestyle in regard to increasing WC over time.

Short-term food deprivation before a fish oil finishing strategy improves the deposition of n-3 LC-PUFA, but not the washing-out of C18 PUFA in rainbow trout

This study aimed to test the hypothesis that the efficiency of a finishing period can be improved by reducing the initial fat content of fish fillets, by means of a period of food deprivation. Two groups of rainbow trout (Oncorhynchus mykiss) were fed for an 18-week grow-out period on a vegetable oil-based diet (VO) or a fish oil-based diet (FO). VO fed fish were then split into two sub groups: one (VO/FO) was shifted to the FO diet for 8 weeks, whilst the other (UF/FO) was deprived of food (unfed) for 2 weeks and then fed the FO diet for the remaining 6 weeks. The control treatment (FO/FO) was represented by fish continuously fed FO. The subsequent reduction of total fat in the UF/FO treatment was then responsible for a much faster recovery towards a FO-like fatty acid profile, validating the proposed hypothesis. However, the modification of the fatty acid composition of fish fillets during the feed withholding period, coupled with the postponement of the finishing diet, resulted in only minor beneficial effects of this strategy, and the loss of potential weight gain. However, the n-3 LC-PUFA content in UF/VO fish fillets was significantly higher than fish subjected to the VO/FO treatment.

Healthy-lifestyle behaviors associated with overweight and obesity in US rural children

Background

There are disproportionately higher rates of overweight and obesity in poor rural communities but studies exploring children’s health-related behaviors that may assist in designing effective interventions are limited. We examined the association between overweight and obesity prevalence of 401 ethnically/racially diverse, rural school-aged children and healthy-lifestyle behaviors: improving diet quality, obtaining adequate sleep, limiting screen-time viewing, and consulting a physician about a child’s weight.
Methods

A cross-sectional analysis was conducted on a sample of school-aged children (6–11 years) in rural regions of California, Kentucky, Mississippi, and South Carolina participating in CHANGE (Creating Healthy, Active, and Nurturing Growing-up Environments) Program, created by Save the Children, an independent organization that works with communities to improve overall child health, with the objective to reduce unhealthy weight gain in these school-aged children (grades 1–6) in rural America. After measuring children’s height and weight, we17 assessed overweight and obesity (BMI ≥ 85th percentile) associations with these behaviors: improving diet quality18 (≥ 2 servings of fruits and vegetables/day), reducing whole milk, sweetened beverage consumption/day; obtaining19 adequate night-time sleep on weekdays (≥ 10 hours/night); limiting screen-time (i.e., television, video, computer,20 videogame) viewing on weekdays (≤ 2 hours/day); and consulting a physician about weight. Analyses were adjusted 21 for state of residence, children's race/ethnicity, gender, age, and government assistance.
Results

Overweight or obesity prevalence was 37 percent in Mississippi and nearly 60 percent in Kentucky. Adjusting for covariates, obese children were twice as likely to eat ≥ 2 servings of vegetables per day (OR=2.0,95% CI 1.1-3.4), less likely to consume whole milk (OR=0.4,95% CI 0.2-0.70), Their parents are more likely to be told by their doctor that their child was obese (OR=108.0,95% CI 21.9-541.6), and less likely to report talking to their child about fruits and vegetables a lot/sometimes vs. not very much/never (OR=0.4, 95%CI 0.2-0.98) compared to the parents of healthy-weight children.
Conclusions

Rural children are not meeting recommendations to improve diet, reduce screen time and obtain adequate sleep. Although we expected obese children to be more likely to engage in unhealthy behaviors, we found the opposite to be true. It is possible that these groups of respondent parents were highly aware of their weight status and have been advised to change their children’s health behaviors. Perhaps given the opportunity to participate in an intervention study in combination with a physician recommendation could have resulted in actual behavior change.

What to do when you can’t (afford to) collect your own data? : a test case using the longitudinal study of Australian children to investigate the influence of parental context on media use and obesity

The dramatic rise in childhood obesity prevalence in the last two decades has prompted concern about the risk factors that may precipitate or maintain weight gain, or both, in early childhood. Media use has long been implicated in policy debates in Australia, particularly around limits to advertising. However the Australian research funding ecology and dominant paradigms in Australian communication and media studies have resulted in a lack of independent, nationally representative studies upon which to base advice. Australian researchers often can’t afford to collect the kind of data they would like in order to intervene productively as policy actors. As a test case for innovative ways round this dilemma, this paper mobilises secondary data analysis methodologies to explore potential influences of parenting on children’s media use and their weight status.

The research reported here uses data from the first three waves of the Longitudinal Study of Australian Children. Results from a path model suggest that children of mothers who were less consistent in the way in which they enforce their rules were more likely to adopt unhealthy lifestyle behaviours, such as sedentary behaviour and consuming unhealthy snacks. Of the lifestyle behaviours considered, time spent watching television or DVDs was the only predictor of child weight status in late childhood. These results suggest a clear pathway linking consistent parenting and other parental practices, children’s lifestyle behaviours and weight status.

Multilevel analysis of the Be Active Eat Well intervention : environmental and behavioural influences on reductions in child obesity risk

Background: The Be Active Eat Well (BAEW) community-based child obesity prevention intervention was successful in modestly reducing unhealthy weight gain in primary school children using a multi-strategy and multi-setting approach.

Objective: To (1) examine the relationship between changes in obesity-related individual, household and school factors and changes in standardised child body mass index (zBMI), and (2) determine if the BAEW intervention moderated these effects.

Methods: The longitudinal relationships between changes in individual, household and school variables and changes in zBMI were explored using multilevel modelling, with measurement time (baseline and follow-up) at level 1, individual (behaviours, n=1812) at level 2 and households (n=1318) and schools (n=18) as higher levels (environments). The effect of the intervention was tested while controlling for child age, gender and maternal education level.

Results: This study confirmed that the BAEW intervention lowered child zBMI compared with the comparison group (−0.085 units, P=0.03). The variation between household environments was found to be a large contributor to the percentage of unexplained change in child zBMI (59%), compared with contributions from the individual (23%) and school levels (1%). Across both groups, screen time (P=0.03), sweet drink consumption (P=0.03) and lack of household rules for television (TV) viewing (P=0.05) were associated with increased zBMI, whereas there was a non-significant association with the frequency the TV was on during evening meals (P=0.07). The moderating effect of the intervention was only evident for the relationship between the frequency of TV on during meals and zBMI, however, this effect was modest (P=0.04).

Conclusions: The development of childhood obesity involves multi-factorial and multi-level influences, some of which are amenable to change. Obesity prevention strategies should not only target individual behaviours but also the household environment and family practices. Although zBMI changes were modest, these findings are encouraging as small reductions can have population level impacts on childhood obesity levels.

Effectiveness of interventions to promote physical activity among socioeconomically disadvantaged women : a systematic review and meta-analysis

Physical activity is important for preventing weight gain and obesity, but women experiencing socioeconomic disadvantage are at high risk of inactivity. This study aimed to determine the effectiveness of interventions to increase physical activity among women experiencing disadvantage, and the intervention factors (i.e. physical activity measure, delivery mode, delivery channel, setting, duration, use of theory, behavioural techniques, participant age, risk of bias) associated with effectiveness. We conducted a meta-analysis of controlled trials using random-effects models and meta-regression. Seven databases were searched for trials among healthy women (18–64 years), which included a physical activity intervention, any control group, and statistical analyses of a physical activity outcome at baseline and post-intervention. Nineteen studies were included (n = 6,339). Because of substantial statistical heterogeneity (χ2 = 53.61, df = 18, P < 0.0001, I2 = 66%), an overall pooled effect is not reported. In subgroup analyses, between-group differences were evident for delivery mode, which modestly reduced heterogeneity (to 54%). Studies with a group delivery component had a standardized mean difference of 0.38 greater than either individual or community-based delivery. Programs with a group delivery mode significantly increase physical activity among women experiencing disadvantage, and group delivery should be considered an essential element of physical activity promotion programs targeting this population group.

Experiences of migration and the determinants of obesity among recent Iranian immigrants in Victoria, Australia

Objectives. There is evidence to suggest that immigrant groups from low- or medium-human development index countries show a significant adoption of obesogenic behaviors and experience weight gain following migration to Australia. The objective of this study is to understand the changes that Iranian immigrants experience in relation to the determinants of obesity after migration to Victoria, Australia.

Design. We conducted five focus group discussions with 33 recent Iranian immigrants. This study took an interpretive qualitative approach to data analysis using the constant comparative method.

Results. Participants discussed individual level acculturation (e.g., in diet, body size, attitudes), as well as environmental level changes (e.g., physical/structural and sociocultural) that occurred after immigration. Stress during the initial immigration transition, which affected diet and physical activity habits, was a common experience among participants. Gender and the effect of political/religious changes were also important factors. Participants' discourse largely focused on their ability and willingness to adopt positive health behaviors after migration.

Conclusion. This study provides insight into the effect of migration on the determinants of obesity among Iranian immigrants in Victoria, Australia, and offers a contrast with the existing evidence by considering the experience of a group that is generally well educated, often emigrates for reasons related to personal freedom as opposed to material deprivation, and has rates of obesity similar to high-income countries.

Does the availability of snack foods in supermarkets vary internationally?

Background
Cross-country differences in dietary behaviours and obesity rates have been previously reported. Consumption of energy-dense snack foods and soft drinks are implicated as contributing to weight gain, however little is known about how the availability of these items within supermarkets varies internationally. This study assessed variations in the display of snack foods and soft drinks within a sample of supermarkets across eight countries.

Methods
Within-store audits were used to evaluate and compare the availability of potato chips (crisps), chocolate, confectionery and soft drinks. Displays measured included shelf length and the proportion of checkouts and end-of-aisle displays containing these products. Audits were conducted in a convenience sample of 170 supermarkets across eight developed nations (Australia, Canada, Denmark, Netherlands, New Zealand, Sweden, United Kingdom (UK), and United States of America (US)).

Results
The mean total aisle length of snack foods (adjusted for store size) was greatest in supermarkets from the UK (56.4 m) and lowest in New Zealand (21.7 m). When assessed by individual item, the greatest aisle length devoted to chips, chocolate and confectionery was found in UK supermarkets while the greatest aisle length dedicated to soft drinks was in Australian supermarkets. Only stores from the Netherlands (41%) had less than 70% of checkouts featuring displays of snack foods or soft drinks.

Conclusion
Whilst between-country variations were observed, overall results indicate high levels of snack food and soft drinks displays within supermarkets across the eight countries. Exposure to snack foods is largely unavoidable within supermarkets, increasing the likelihood of purchases and particularly those made impulsively.