Time Dependent Surface Corrosion Analysis and Modelling of Automotive Steel Under a Simplistic Model of Variations in Environmental Parameters

This research presents time-dependent corrosion analysis of automotive steel utilised in a large military vehicle in real operating environment, followed by simulated environmental tests and simplistic surface corrosion modelling. Time-dependent surface corrosion accumulated on this specific component was observed to be approximately 250 µm thick, with the identification of surface contaminants such as chlorine and sulphur. Simulated environmental tests considering temperature and relative humidity variations were performed to evaluate quantitative corrosion damage to the structure of the vehicle. The relationship of various temperatures and relative humidity with respect to time, within the context of corrosion initiation and propagation, has been presented. A mathematical model to incorporate corrosion accumulation on the surfaces derived from the simulated environmental tests is presented

Comparing very low birth weight versus very low gestation cohort methods for outcome analysis of high risk preterm infants

Background: Compared to very low gestational age (\u3c32 weeks, VLGA) cohorts, very low birth weight (\u3c1500 g; VLBW) cohorts are more prone to selection bias toward small-for-gestational age (SGA) infants, which may impact upon the validity of data for benchmarking purposes. Method: Data from all VLGA or VLBW infants admitted in the 3 Networks between 2008 and 2011 were used. Two-thirds of each network cohort was randomly selected to develop prediction models for mortality and composite adverse outcome (CAO: mortality or cerebral injuries, chronic lung disease, severe retinopathy or necrotizing enterocolitis) and the remaining for internal validation. Areas under the ROC curves (AUC) of the models were compared. Results: VLBW cohort (24,335 infants) had twice more SGA infants (20.4% vs. 9.3%) than the VLGA cohort (29,180 infants) and had a higher rate of CAO (36.5% vs. 32.6%). The two models had equal prediction power for mortality and CAO (AUC 0.83), and similarly for all other cross-cohort validations (AUC 0.81-0.85). Neither model performed well for the extremes of birth weight for gestation (\u3c1500 g and ≥32 weeks, AUC 0.50-0.65; ≥1500 g and \u3c32 weeks, AUC 0.60-0.62). Conclusion: There was no difference in prediction power for adverse outcome between cohorting VLGA or VLBW despite substantial bias in SGA population. Either cohorting practises are suitable for international benchmarking

Perinatal mortality following assisted reproductive technology treatment in Australia and New Zealand, a public health approach for international reporting of perinatal mortality

BACKGROUND There is a need to have uniformed reporting of perinatal mortality for births following assisted reproductive technology (ART) treatment to enable international comparison and benchmarking of ART practice. METHODS The Australian and New Zealand Assisted Reproduction Database was used in this study. Births of ≥ 20 weeks gestation and/or ≥ 400 grams of birth weight following embryos transfer cycles in Australia and New Zealand during the period 2004 to 2008 were included. Differences in the mortality rates by different perinatal periods from a gestational age cutoff of ≥ 20, ≥ 22, ≥ 24, or ≥ 28 weeks (wks) to a neonatal period cutoff of either < 7 or < 28 days after birth were assessed. Crude and specific (number of embryos transferred and plurality) rates of perinatal mortality were calculated for selected gestational and neonatal periods. RESULTS When the perinatal period is defined as ≥ 20 wks gestation to < 28 days after birth, the perinatal mortality rate (PMR) was 16.1 per 1000 births (n = 630). A progressive contraction of the gestational age groups resulted in marked reductions in the PMR for deaths at < 28 days (22 wks 11.0; 24 wks 7.7; 28 wks 5.6); and similarly for deaths at < 7 days (20 wks 15.6, 22 wks 10.5; 24 wks 7.3; 28 wks 5.3). In contrast, a contraction of the perinatal period from < 28 to < 7 days after birth only marginally reduced the PMR from 16.2 to 15.6 per 1000 births which was consistent across all gestational ages. The PMR for single embryo transfer (SET) births (≥ 20 weeks gestation to < 7 days post-birth) was significantly lower (12.8 per 1000 SET births) compared to double embryo transfer (DET) births (PMR 18.3 per 1000 DET births; p < 0.001, Fisher’s Exact Test). Similarly, the PMR for SET births (≥ 22 weeks gestation to < 7 days post-birth) was significantly lower (8.8 per 1000 SET births, p < 0.001, Fisher’s Exact Test) when compared to DET births (12.2 per 1000 DET births). The highest PMR (50.5 per 1000 SET births, 95% CI 36.5-64.5) was for twins following SET births (≥ 20 weeks gestation to < 7 days post-birth) compared to twins following DET (23.9 per 1000 DET births, 95% CI 20.8-27.1). CONCLUSION Reporting of perinatal mortality of ART births is an essential component of quality ART practice. This should include measures that monitor the impact on perinatal mortality of multiple embryo transfer. We recommend that reporting of perinatal deaths following ART treatment, should be stratified for three gestation-specific perinatal periods of ≥ 20, ≥ 22 and ≥ 28 completed weeks to < 7 days post-birth; and include plurality specific rates by SET and DET. This would provide a valuable international evidence-base of PMR for use in evaluating ART policy, practice and new research.Elizabeth A Sullivan, Yueping A Wang, Robert J Norman, Georgina M Chambers, Abrar Ahmad Chughtai and Cynthia M Farquha

Assisted reproductive technology in Australia and New Zealand 2007

This is the thirteenth annual report on the use of ART in Australia and New Zealand, and presents data on women who underwent ART treatments in 2007, and the resulting pregnancies and baby outcomes. Assisted reproductive technologies (ART) — such as in vitro fertilisation (IVF) — are a group of procedures used to assist women to become pregnant. ART usually involves removing oocytes (eggs) from a woman’s ovaries, fertilising them in the laboratory and then transferring the resulting embryo(s) back into a woman’s uterus. Over the last five years, the number of ART procedures has increased on average by over 10% per year in Australia and New Zealand. Latest estimates indicate that 3.1% and 1.8% of babies born in Australia and New Zealand respectively are as a result of ART treatment. In 2007, there were 56,817 assisted reproductive technology (ART) treatment cycles undertaken in Australian and New Zealand. Of these cycles, 17.4% resulted in a live delivery (the birth of at least one liveborn baby). In total, 10,856 liveborn babies were born following ART treatment undertaken in 2007. The most important recent trend in ART treatment has been the reduction in the rate of twins and triplets births, with the multiple delivery rate falling from 18.7% in 2003 to 10.0% in 2007. This trend has been associated with an increase in the proportion of ART treatment cycles using single embryo transfer, from 32.0% in 2003 to 63.7% in 2007. Authored by Wang YA, Chambers G, Dieng M &amp; Sullivan EA

Assisted reproduction technology in Australia and New Zealand 2005

This report presents data on success rates based on live delivery and how they vary by treatment type, women\u27s age and number of embryos transferred. Also included is information on birth outcomes such as multiple birth, gestational age, birthweight, and perinatal mortality

Assisted reproductive technology in Australia and New Zealand 2008

In 2008, there were 61,929 assisted reproductive technology (ART) treatment cycles undertaken in Australia and New Zealand. Of these cycles, 17.2% resulted in a live delivery (the birth of at least one liveborn baby). In total, 11,528 liveborn babies were born following ART treatment undertaken in 2008. The most important trend in ART treatment has been the increase of single embryo transfer, from 40.5% in 2004 to 67.8% in 2008. This trend has resulted in significant reduction of multiple delivery rate, from 16.4% in 2004 to 8.4% in 2008

The urban-remote divide for Indigenous perinatal outcomes

Objective: To determine whether remoteness category of residence of Indigenous women affects the perinatal outcomes of their newborn infants. Design and participants: A population-based study of 35240 mothers identified as Indigenous and their 35658 babies included in the National Perinatal Data Collection in 2001-2004. Main outcome measures: Australian Standard Geographical Classification remoteness category, birthweight, Apgar score at 5 minutes, stillbirth, gestational age and a constructed measure of perinatal outcomes of babies called "healthy baby" (live birth, singleton, 37-41 completed weeks' gestation, 2500-4499 g birthweight, and an Apgar score at 5 minutes ≥ 7). Results: The proportion of healthy babies in remote, regional and city areas was 74.9%, 77.7% and 77.6%, respectively. After adjusting for age, parity, smoking and diabetes or hypertension, babies born to mothers in remote areas were less likely to satisfy the study criteria of being a healthy baby (adjusted odds ratio [AOR], 0.87; 95% CI, 0.81-0.93) compared with those born in cities. Babies born to mothers living in remote areas had higher odds of being of low birthweight (AOR, 1.09; 95% CI, 1.01-1.19) and being born with an Apgar score < 7 at 5 minutes (AOR, 1.63; 95% CI, 1.39-1.92). Conclusions: Only three in four babies born to Indigenous mothers fell into the "healthy baby" category, and those born in more remote areas were particularly disadvantaged. These findings demonstrate the continuing need for urgent and concerted action to address the persistent perinatal inequity in the Indigenous population