Resuspension of the aortic valve in acute type A dissection: long-term results

BACKGROUND AND AIM OF THE STUDY: Preservation of the aortic valve during the repair of acute type A aortic dissection (AADA) is a viable option to prevent lifelong oral anticoagulation. The study aim was to assess aortic valve function following resuspension and supracoronary ascending aortic grafting. METHODS: Among a collective of 210 consecutive patients undergoing surgery for AADA, 140 (66.7%) with resuspension of the aortic valve and supracoronary ascending graft were analyzed. Of these patients, 83 (59.3%) had a complete follow up (mean 61.2 +/- 40.8 months), with 65 of the subgroup (78.3%) being followed by computed tomography scanning and echocardiography. RESULTS: Reoperation due to severe aortic valve regurgitation was required in seven patients (10.8%). The perioperative characteristics were similar in these patients; notably, no significant difference was evident with regards to the aortic annulus diameter and the severity of regurgitation at the time of surgery. The left ventricular mass index was significantly higher in patients requiring reoperation due to aortic valve regurgitation (219.3 +/- 146.6 versus 123.9 +/- 146.6 g/m2; p <0.05). None of the patients died as a result of reoperation. CONCLUSION: The long-term functional results following resuspension of the aortic valve in AADA were very good. A close echocardiographic follow up was necessary, as reoperation of the aortic valve was required in more than 10% of the collective, with an average follow up of five years. Reoperation was mainly related to secondary dilatation of the aortic root.

Long-term expression of protein kinase C in adult mouse hearts improves postischemic recovery

Activation of protein kinase C (PKC) protects the heart from ischemic injury; however, its mechanism of action is unknown, in part because no model for chronic activation of PKC has been available. To test whether chronic, mild elevation of PKC activity in adult mouse hearts results in myocardial protection during ischemia or reperfusion, hearts isolated from transgenic mice expressing a low level of activated PKCβ throughout adulthood (β-Tx) were compared with control hearts before ischemia, during 12 or 28 min of no-flow ischemia, and during reperfusion. Left-ventricular-developed pressure in isolated isovolumic hearts, normalized to heart weight, was similar in the two groups at baseline. However, recovery of contractile function was markedly improved in β-Tx hearts after either 12 (97 ± 3% vs. 69 ± 4%) or 28 min of ischemia (76 ± 8% vs. 48 ± 3%). Chelerythrine, a PKC inhibitor, abolished the difference between the two groups, indicating that the beneficial effect was PKC-mediated. 31P NMR spectroscopy was used to test whether modification of intracellular pH and/or preservation of high-energy phosphate levels during ischemia contributed to the cardioprotection in β-Tx hearts. No difference in intracellular pH or high-energy phosphate levels was found between the β-Tx and control hearts at baseline or during ischemia. Thus, long-term modest increase in PKC activity in adult mouse hearts did not alter baseline function but did lead to improved postischemic recovery. Furthermore, our results suggest that mechanisms other than reduced acidification and preservation of high-energy phosphate levels during ischemia contribute to the improved recovery.

Long-term assessment of efficacy of permeable pond covers for odour reduction

Three anaerobic ponds used to store and treat piggery wastes were fully covered with permeable materials manufactured from polypropylene geofabric, polyethylene shade cloth and supported straw. The covers were assessed in terms of efficacy in reducing odour emission rates over a 40-month period. Odour samples were collected from the surface of the covers, the surface of the exposed liquor and from the surface of an uncovered (control) pond at one of the piggeries. Relative to the emission rate of the exposed liquor at each pond, the polypropylene, shade cloth and straw covers reduced average emission rates by 76%, 69% and 66% respectively. At the piggery with an uncovered control pond, the polypropylene covers reduced average odour emission rates by 50% and 41% respectively. A plausible hypothesis, consistent with likely mechanisms for the odour reduction and the olfactometric method used to quantifying the efficacy of the covers, is offered.

Long-term trends in fine particle number concentrations in the urban atmosphere of Brisbane : the relevance of traffic emissions and new particle formation

The measurement of submicrometre (< 1.0 m) and ultrafine particles (diameter < 0.1 m) number concentration have attracted attention since the last decade because the potential health impacts associated with exposure to these particles can be more significant than those due to exposure to larger particles. At present, ultrafine particles are not regularly monitored and they are yet to be incorporated into air quality monitoring programs. As a result, very few studies have analysed their long-term and spatial variations in ultrafine particle concentration, and none have been in Australia. To address this gap in scientific knowledge, the aim of this research was to investigate the long-term trends and seasonal variations in particle number concentrations in Brisbane, Australia. Data collected over a five-year period were analysed using weighted regression models. Monthly mean concentrations in the morning (6:00-10:00) and the afternoon (16:00-19:00) were plotted against time in months, using the monthly variance as the weights. During the five-year period, submicrometre and ultrafine particle concentrations increased in the morning by 105.7% and 81.5% respectively whereas in the afternoon there was no significant trend. The morning concentrations were associated with fresh traffic emissions and the afternoon concentrations with the background. The statistical tests applied to the seasonal models, on the other hand, indicated that there was no seasonal component. The spatial variation in size distribution in a large urban area was investigated using particle number size distribution data collected at nine different locations during different campaigns. The size distributions were represented by the modal structures and cumulative size distributions. Particle number peaked at around 30 nm, except at an isolated site dominated by diesel trucks, where the particle number peaked at around 60 nm. It was found that ultrafine particles contributed to 82%-90% of the total particle number. At the sites dominated by petrol vehicles, nanoparticles (< 50 nm) contributed 60%-70% of the total particle number, and at the site dominated by diesel trucks they contributed 50%. Although the sampling campaigns took place during different seasons and were of varying duration these variations did not have an effect on the particle size distributions. The results suggested that the distributions were rather affected by differences in traffic composition and distance to the road. To investigate the occurrence of nucleation events, that is, secondary particle formation from gaseous precursors, particle size distribution data collected over a 13 month period during 5 different campaigns were analysed. The study area was a complex urban environment influenced by anthropogenic and natural sources. The study introduced a new application of time series differencing for the identification of nucleation events. To evaluate the conditions favourable to nucleation, the meteorological conditions and gaseous concentrations prior to and during nucleation events were recorded. Gaseous concentrations did not exhibit a clear pattern of change in concentration. It was also found that nucleation was associated with sea breeze and long-range transport. The implications of this finding are that whilst vehicles are the most important source of ultrafine particles, sea breeze and aged gaseous emissions play a more important role in secondary particle formation in the study area.

Long term sustainability in exporting creativity

This project aims to assess the extent of economic sustainability of working in international markets by Australian construction design-related firms. This investigation also identified barriers and success factors firms experience, which ultimately increases or reduces their exposure to financial risk. This study explored new research territory by developing a detailed understanding of the way three successful firms have maintained their longevity in various international markets. The firms are not considered to be large firms by international standards. The manner in which the firms achieve long term sustainability, deal with problems and barriers in international markets and develop successful strategies rely upon being adaptable to different markets and changes within markets. A model was developed based upon a critical analysis of the literature. An adaptive performance framework for sustainability was developed which had three key areas; internationalisation process, market knowledge and design management. The sustainable business model is underpinned by the management of non-economic factors, which include social, cultural and intellectual capital. The ultimate aim of any firm and the ultimate indicator of success is financial capital. Firms typically develop their own highly sophisticated financial measures themselves however have only an implicit understanding of other softer and less tangible factors that impact upon sustainability. Adaptive performance is the firm’s continual adaptivity of business practices to respond to and thereby achieve client satisfaction by a combination of self, market and project needs assessment.

Long-term outcomes of seriously injured children : a study using the Child Health Questionnaire

Objective: To assess the health-related quality of life (HRQoL) in children 1-2 years after they had sustained an injury. Methods: Parents of all children who were identified by the Queensland Trauma Registry during their admission to either of the two paediatric specialty hospitals in Brisbane, Australia, for the treatment of an injury, were invited to participate in this study. Parents who consented to participation received a copy of the Child Health Questionnaire (CHQ) that required them to provide information regarding their child’s HRQoL following injury. The CHQ scores for the study respondents were compared with those of the Australian norms. This study was approved by the relevant ethics committees. Results: Two hundred and forty-one completed questionnaires were returned. The majority of cases were male (65%) and there was even representation across all age groups. The majority of injuries were considered to be minor (81%) and were predominantly the result of falls and cycling accidents causing mainly fractures and intracranial injury. On the majority of subscales of the CHQ, study participants recorded scores that were statistically significantly below those of the Australian norms. None of the relevant variables collected by the Queensland Trauma Registry were found to predict scores on the CHQ in this study (for those children hospitalized for >24 h). Conclusion: Injured children are worse off than their Australian counterparts in terms of HRQoL even up to 2 years following an injury. Further research needs to be undertaken to identify factors that predict lower HRQoL in order to reduce the burden of injury on children and their families.

In search of a hidden long-term isolated sub-chondritic 142Nd/144Nd reservoir in the deep mantle : implications for the Nd isotope systematics of the Earth

Here we search for evidence of the existence of a sub-chondritic 142Nd/144Nd reservoir that balances the Nd isotope chemistry of the Earth relative to chondrites. If present, it may reside in the source region of deeply sourced mantle plume material. We suggest that lavas from Hawai’i with coupled elevations in 186Os/188Os and 187Os/188Os, from Iceland that represent mixing of upper mantle and lower mantle components, and from Gough with sub-chondritic 143Nd/144Nd and high 207Pb/206Pb, are favorable samples that could reflect mantle sources that have interacted with an Early-Enriched Reservoir (EER) with sub-chondritic 142Nd/144Nd. High-precision Nd isotope analyses of basalts from Hawai’i, Iceland and Gough demonstrate no discernable 142Nd/144Nd deviation from terrestrial standards. These data are consistent with previous high-precision Nd isotope analysis of recent mantle-derived samples and demonstrate that no mantle-derived material to date provides evidence for the existence of an EER in the mantle. We then evaluate mass balance in the Earth with respect to both 142Nd/144Nd and 143Nd/144Nd. The Nd isotope systematics of EERs are modeled for different sizes and timing of formation relative to ε143Nd estimates of the reservoirs in the μ142Nd = 0 Earth, where μ142Nd is ((measured 142Nd/144Nd/terrestrial standard 142Nd/144Nd)−1 * 10−6) and the μ142Nd = 0 Earth is the proportion of the silicate Earth with 142Nd/144Nd indistinguishable from the terrestrial standard. The models indicate that it is not possible to balance the Earth with respect to both 142Nd/144Nd and 143Nd/144Nd unless the μ142Nd = 0 Earth has a ε143Nd within error of the present-day Depleted Mid-ocean ridge basalt Mantle source (DMM). The 4567 Myr age 142Nd–143Nd isochron for the Earth intersects μ142Nd = 0 at ε143Nd of +8 ± 2 providing a minimum ε143Nd for the μ142Nd = 0 Earth. The high ε143Nd of the μ142Nd = 0 Earth is confirmed by the Nd isotope systematics of Archean mantle-derived rocks that consistently have positive ε143Nd. If the EER formed early after solar system formation (0–70 Ma) continental crust and DMM can be complementary reservoirs with respect to Nd isotopes, with no requirement for significant additional reservoirs. If the EER formed after 70 Ma then the μ142Nd = 0 Earth must have a bulk ε143Nd more radiogenic than DMM and additional high ε143Nd material is required to balance the Nd isotope systematics of the Earth.

Safeguarding rural Australia : addressing masculinity and violence in rural settings. Data report no. 5. Consequences of violence - juvenile offenders, long-term health consequences, anxiety and repression, other chronic disabilities

This report considers extant data which have been sourced with respect to some of the consequences of violent acts and incidents and risky behaviour for males living in regional and remote Australia . This has been collated and presented under the headings: juvenile offenders; long-term health consequences; anxiety and repression; and other chronic disabilities. Additional commentary resulting from exploration, examination and analyses of secondary data is published online in complementary reports in this series.

Long-term exposure to gaseous air pollutants and cardio-respiratory mortality in Brisbane, Australia

Air pollution is ranked by the World Health Organisation as one of the top ten contributors to the global burden of disease and injury. Exposure to gaseous air pollutants, even at a low level, has been associated with cardiorespiratory diseases (Vedal, Brauer et al. 2003). Most recent epidemiological studies of air pollution have used time-series analyses to explore the relationship between daily mortality or morbidity and daily ambient air pollution concentrations based on the same day or previous days (Hajat, Armstrong et al. 2007). However, most of the previous studies have examined the association between air pollution and health outcomes using air pollution data from a single monitoring site or average values from a few monitoring sites to represent the whole population of the study area. In fact, for a metropolitan city, ambient air pollution levels may differ significantly among the different areas. There is increasing concern that the relationships between air pollution and mortality may vary with geographical area (Chen, Mengersen et al. 2007). Additionally, some studies have indicated that socio-economic status can act as a confounder when investigating the relation between geographical location and health (Scoggins, Kjellstrom et al. 2004). This study examined the spatial variation in the relationship between long-term exposure to gaseous air pollutants (including nitrogen dioxide (NO2), ozone (O3) and sulphur dioxide (SO2)), and cardiorespiratory mortality in Brisbane, Australia, during the period 1996 - 2004.