Theory of Exciton Migration and Field-Induced Dissociation in Conjugated Polymers

The interplay of migration, recombination, and dissociation of excitons in disordered media is studied theoretically in the low temperature regime. An exact expression for the photoluminescence spectrum is obtained. The theory is applied to describe the electric field-induced photoluminescence-quenching experiments by Kersting et al. [Phys. Rev. Lett. 73, 1440 (1994)] and Deussen et al. [Synth. Met. 73, 123 (1995)] on conjugated polymer systems. Good agreement with experiment is obtained using an on-chain dissociation mechanism, which implies a separation of the electron-hole pair along the polymer chain.Comment: 4 pages, RevTeX, 2 Postscript figure

Theory of Electric Field-Induced Photoluminescence Quenching in Disordered Molecular Solids

The dynamics of excitons in disordered molecular solids is studied theoretically, taking into account migration between different sites, recombination, and dissociation into free charge carriers in the presence of an electric field. The theory is applied to interpret the results of electric field-induced photoluminescence (PL) quenching experiments on molecularly doped polymers by Deussen et al. [Chem. Phys. 207, 147 (1996)]. Using an intermolecular dissociation mechanism, the dependence of the PL quenching on the electric field strength and the dopant concentration, and the time evolution of the transient PL quenching can be well described. The results constitute additional proof of the distinct exciton dissociation mechanisms in conjugated polymer blends and molecularly doped polymers.Comment: 4 pages RevTeX, 3 Postscript figure

Developing a tool for obtaining maternal skinfold thickness measurements and assessing inter-observer variability among pregnant women who are overweight and obese

Extent: 6p.Background: It is estimated that between 34% and 50% of Australian women entering pregnancy are overweight and obese, which is associated with an increased risk in complications for both the woman and her infant. Current tools used in clinical and research practice for measuring body composition include body mass index (BMI), waist circumference and bioimpedance analysis. Not all of these measures are applicable for use during pregnancy due to a lack of differentiation between maternal and fetal contributions. While skinfold thickness measurement (SFTM) is increasingly being used in pregnancy, there is limited data and a lack of a standard tool for its use in overweight and obese pregnant women. Methods: We developed a standard tool for evaluating SFTM among women with a BMI ≥ 25 kg/m2. Forty-nine women were measured as part of a prospective cohort study nested within a multicentre randomised controlled trial (The LIMIT Randomised Controlled Trial). Two blinded observers each performed 2 skinfold measurements on the biceps, triceps and subscapular of each woman. Intraclass correlation coefficients (ICC) and standard error of measurement (SEM) were used to analyse SFTM, body fat percentage (BF%) and inter-observer variability. Results: The ICC for inter-observer variability in measurements were considered moderate for biceps SFTM (ICC = 0.56) and triceps SFTM (ICC = 0.51); good for subscapular SFTM (ICC = 0.71) and BF% (ICC = 0.74); and excellent for arm circumference (ICC = 0.97). The standard error of measurements ranged from 0.53 cm for arm circumference to 3.58 mm for the subscapular SFTM. Conclusion: Our findings indicate that arm circumference and biceps, triceps and subscapular SFTM can be reliably obtained from overweight and obese pregnant women to calculate BF%, using multiple observers, and can be used in a research setting.Lavern M Kannieappan, Andrea R Deussen, Rosalie M Grivell, Lisa Yelland and Jodie M Dod

Paternal obesity modifies the effect of an antenatal lifestyle intervention in women who are overweight or obese on newborn anthropometry

The contribution of paternal obesity to pregnancy outcomes has been little described. Our aims were to determine whether the effect of an antenatal maternal dietary and lifestyle intervention among women who are overweight or obese on newborn adiposity, was modified by paternal obesity. We conducted a secondary analysis of a multicenter randomised trial. Pregnant women with BMI ≥25 kg/m2 received either Lifestyle Advice or Standard Care. Paternal anthropometric measures included height, weight, BMI; waist, hip, calf and mid-upper arm circumferences; biceps and calf skinfold thickness measurements (SFTM); and percentage body fat. Newborn anthropometric outcomes included length; weight; head, arm, abdominal, and chest circumferences; biceps, triceps, subscapular, suprailiac, thigh, and lateral abdominal wall SFTM; and percentage body fat. The effect of an antenatal maternal dietary and lifestyle intervention among women who were overweight or obese on neonatal anthropometric measures, was significantly modified by paternal BMI ≥35.0 kg/m2, with a significantly smaller infant triceps, suprailiac, and thigh SFTM, and percent fat mass, compared with that observed in offspring of lean fathers. Further research is required to determine whether our observed associations are causal, and whether paternal weight loss prior to conception is a potential strategy to reduce the intergenerational effects of obesity.Jodie M. Dodd, Lodewyk E. Du Plessis, Andrea R. Deussen, Rosalie M. Grivell, Lisa N. Yelland, Jennie Louise, Andrew J. Mcphee, Jeffrey S. Robinson and Julie A. Owen

A randomised trial to optimise gestational weight gain and improve maternal and infant health outcomes through antenatal dietary, lifestyle and exercise advice: the OPTIMISE randomised trial

There are well-recognised associations between excessive gestational weight gain (GWG) and adverse pregnancy outcomes, including an increased risk of pre-eclampsia, gestational diabetes and caesarean birth. The aim of the OPTIMISE randomised trial was to evaluate the effect of dietary and exercise advice among pregnant women of normal body mass index (BMI), on pregnancy and birth outcomes. The trial was conducted in Adelaide, South Australia. Pregnant women with a body mass index in the healthy weight range (18.5-24.9 kg/m2) were enrolled in a randomised controlled trial of a dietary and lifestyle intervention versus standard antenatal care. The dietitian-led dietary and lifestyle intervention over the course of pregnancy was based on the Australian Guide to Healthy Eating. Baseline characteristics of women in the two treatment groups were similar. There was no statistically significant difference in the proportion of infants with birth weight above 4.0 kg between the Lifestyle Advice and Standard Care groups (24/316 (7.59%) Lifestyle Advice versus 26/313 (8.31%) Standard Care; adjusted risk ratio (aRR) 0.91; 95% confidence interval (CI) 0.54 to 1.55; p = 0.732). Despite improvements in maternal diet quality, no significant differences between the treatment groups were observed for total GWG, or other pregnancy and birth outcomes.Jodie M. Dodd, Andrea R. Deussen and Jennie Louis

Optimising gestational weight gain and improving maternal and infant health outcomes through antenatal dietary, lifestyle and physical activity advice: the OPTIMISE randomised controlled trial protocol

Introduction: Obesity represents a significant health burden, and WHO recognises the importance of preventing weight gain and subsequent development of obesity among adults who are within the healthy weight range. Women of reproductive age have demonstrated high rates of weight gain during pregnancy placing them at risk of becoming overweight or obese. We will evaluate the effects of dietary and physical activity advice on maternal, fetal and infant health outcomes, among pregnant women of normal body mass index (BMI). Methods and analysis: We will conduct a randomised controlled trial, consenting and randomising women with a live singleton pregnancy between 10+0 and 20+0 weeks and BMI 18.5–24.9 kg/m2 at first antenatal visit, from a tertiary maternity hospital. Women randomised to the Lifestyle Advice Group will receive three face-to-face sessions (two with a research dietitian and one with a trained research assistant) and three telephone calls over pregnancy, in which they will be provided with dietary and lifestyle advice and encouraged to make change using a SMART goals approach. Women randomised to the Standard Care Group will receive routine antenatal care. The primary outcome is infant birth weight >4 kg. Secondary outcomes will include adverse infant and maternal outcomes, maternal weight change, maternal diet and physical activity changes, maternal quality of life and emotional well-being, fetal growth and costs of healthcare. We will recruit 624 women to detect a reduction from 8.72% to 3.87% (alpha 0.05 (two-tailed); power 70%) in infants with birth weight >4 kg. Analyses will be intention to treat with estimates reported as relative risks and 95% CIs. Ethics and dissemination: Ethical approval has been obtained from the Women’s and Children’s Hospital ethics committee. Findings will be disseminated widely via journal publication and conference presentation(s), and participants informed of results.Jodie M Dodd, Andrea R Deussen, Jennie Louis

In overweight or obese pregnant women, maternal dietary factors are not associated with fetal growth and adiposity

The aim of our study was to evaluate associations between maternal dietary factors and fetal growth and adiposity in overweight and obese women. Women randomised to the ‘Standard Care’ group of the LIMIT trial were included. Maternal dietary factors including Healthy Eating Index, total energy, fat, carbohydrates, protein, glycaemic load and index were measured using the Harvard semi-quantitative Food Frequency questionnaire at time of study entry, 28 and 36 weeks’ gestation. Fetal ultrasound measurements of biometry and adiposity were obtained at 28 and 36 weeks’ gestation. Linear regression models were used to associate between dietary factors and fetal growth and adiposity measurements. There were 721 women included in this exploratory analysis. A 10 unit increase in the log total energy was associated with a reduction in mid-thigh lean mass by 4.94 mm at 28 weeks (95% CI −9.57 mm, −0.32 mm; p = 0.036) and 7.02 mm at 36 weeks (95% CI −13.69 mm, −0.35 mm; p = 0.039). A 10 unit increase in Healthy Eating Index score was associated with a reduced mean subscapular skin fold measure at 28 weeks by 0.17 mm (95% CI −0.32 mm, −0.03 mm; p = 0.021). We did not identify consistent associations between maternal diet and measures of fetal growth and adiposity in overweight and obese women.Cecelia M. O’Brien, Jennie Louise, Andrea Deussen and Jodie M. Dod

The tools used to assess psychological symptoms in women and their partners after termination of pregnancy for fetal anomaly: A scoping review

Termination of pregnancy for fetal anomaly (TOPFA) represents a uniquely distressing and challenging situation for women and their partners. Having appropriate screening tools that best highlight the psychological symptoms experienced by women and their partners is important to be able to guide care. Many validated screening tools for pregnancy and psychological distress exist, with variation in the ease of application and the domains addressed in each. We undertook a scoping review of tools used to assess psychological symptoms in women and/ or partners after TOPFA. Of 909 studies, 93 studies including 6248 women and 885 partners were included. Most of the included studies assessed symptoms within six months of TOPFA and highlighted high rates of distress, grief and trauma symptoms. There was broad variation in the tools used between studies and the timing of their implementation. Focusing the care of women and families who undergo TOPFA to validated, broadly available and easily applied screening tools that assess a range of psychological symptoms is key in being able to identify the potential interventions that may be of benefit.Laura Slade, Kate Obst, Andrea Deussen, Jodie Dod

The effect of an antenatal lifestyle intervention in overweight and obese women on circulating cardiometabolic and inflammatory biomarkers: secondary analyses from the LIMIT randomised trial

Background: Maternal overweight and obesity during pregnancy is associated with insulin resistance, hyperglycaemia, hyperlipidaemia and a low-grade state of chronic inflammation. The aim of this pre-specified analysis of secondary outcome measures was to evaluate the effect of providing antenatal dietary and lifestyle advice on cardiometabolic and inflammatory biomarkers. Methods: We conducted a multicentre trial in which pregnant women who were overweight or obese were randomised to receive either Lifestyle Advice or Standard Care. We report a range of pre-specified secondary maternal and newborn cardiometabolic and inflammatory biomarker outcomes. Maternal whole venous blood was collected at trial entry (mean 14 weeks gestation; non-fasting), at 28 weeks gestation (fasting), and at 36 weeks gestation (non-fasting). Cord blood was collected after birth and prior to the delivery of the placenta. A range of cardiometabolic and inflammatory markers were analysed (total cholesterol, triglycerides, non-esterified fatty acids, high-density lipoprotein cholesterol, insulin, glucose, leptin, adiponectin, C-reactive protein, granulocyte macrophage-colony stimulating factor, interferon gamma, TNF-α, and interleukins 1β, 2, 4, 5, 6, 8, and 10). Participants were analysed in the groups to which they were randomised, and were included in the analyses if they had a measure at any time point. results: One or more biological specimens were available from 1951 women (989 Lifestyle Advice and 962 Standard Care), with cord blood from 1174 infants (596 Lifestyle Advice and 578 Standard Care). There were no statistically significant differences in mean cardiometabolic and inflammatory marker concentrations across pregnancy and in infant cord blood between treatment groups. Estimated treatment group differences were close to zero, with 95% confidence intervals spanning a range of differences that were short of clinical relevance. There was no evidence to suggest that the intervention effect was modified by maternal BMI category. Conclusions: Despite our findings, it will be worth considering potential relationships between cardiometabolic and inflammatory markers and clinical outcomes, including longer-term infant health and adiposity. Trial Registration: Australian and New Zealand Clinical Trials Registry ( ACTRN12607000161426 ; Date Registered 09/03/2007).Lisa J. Moran, Louise M. Fraser, Tulika Sundernathan, Andrea R. Deussen, Jennie Louise, Lisa N. Yelland, Rosalie M. Grivell, Anne Macpherson, Matthew W. Gillman, Jeffrey S. Robinson, Julie A. Owens and Jodie M. Dod

Features of adenosine metabolism of mouse heart

Adenosine metabolism and transport were evaluated in the isolated perfused mouse heart and compared with the well-established model of isolated perfused guinea pig heart. Coronary venous release of adenosine under well-oxygenated conditions in the mouse exceeds that in the guinea pig threefold when related to tissue mass. Total myocardial adenosine production rate under this condition was approximately 2 nmol/min per gramme and similar in both species. Coronary resistance vessels of mice are highly sensitive to exogenous adenosine, and the threshold for adenosine-induced vasodilation is approximately 30 nmol/l. Adenosine membrane transport was largely insensitive to nitrobenzyl-thioinosine (NBTI) in mouse heart, which is in contrast to guinea pig and several other species. This indicates the dominance of NBTI-insensitive transporters in mouse heart. For future studies, the assessment of cytosolic and extracellular adenosine metabolism and its relationship with coronary flow will require the use of more effective membrane transport blockers