155 research outputs found

    A rural agricultural-sustainable energy community model and its application to Felton Valley, Australia

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    Energy and food security require a delicate balance which should not threaten or undermine community prosperity. Where it is proposed to derive energy from conventional fossil fuel resources (such as coal, shale oil, natural gas, coal seam gas) located in established rural areas, and particularly where these areas are used for productive agricultural purposes, there are often both intense community concern as well as broader questions regarding the relative social, economic and environmental costs and benefits of different land uses and, increasingly, different energy sources. The advent of mainstream renewable energy technologies means that alternative energy options may provide a viable alternative, allowing energy demand to be met without compromising existing land uses. We demonstrate how such a Sustainable Energy Rural Model can be designed to achieve a balance between the competing social goals of energy supply, agricultural production, environmental integrity and social well-being, and apply it to the Felton Valley, a highly productive and resilient farming community in eastern Australia. Research into available wind and solar resources found that Felton Valley has a number of attributes that indicate its suitability for the development of an integrated renewable energy precinct which would complement, rather than displace, existing agricultural enterprises. Modelling results suggest a potential combined annual renewable energy output from integrated wind and solar resources of 1,287 GWh/yr from peak installed capacity of 713 MW, sufficient to supply the electrical energy needs of about 160,000 homes, in combination with total biomass food production of 31,000 tonnes per annum or 146 GWh/yr of human food energy. The portfolio of renewable energy options will not only provide energy source diversity but also ensures long-term food security and regional stability. The Felton Valley model provides an example of community-led energy transformation and has potential as a pilot project for the development of smart distributed grids that would negate the need for further expansion of coal mining and coal fired power stations

    The thermo-oxidative degradation of poly(4-methylstyrene) and its relationship to flammability

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    Polystyrene and poly(4-methylstyrene) have very similar chemical structures with the only differences being the para methyl group of poly(4-methylstyrene). This methyl group is susceptible to oxidation at elevated temperatures. Here we demonstrate that it is possible to introduce oxidative cross-links to poly(4-methylstyrene), via the para methyl group, by thermal oxidative treatment at 230Ā Ā°C, 250Ā Ā°C and 270Ā Ā°C in the absence of catalyst, leading to a material with markedly modified thermal degradation chemistry. Thermal gravimetric analysis and differential scanning calorimetry were used to characterise and compare untreated and post-oxidised materials and established that as the temperature of pre-treatment was increased, the subsequent thermal stability of the material increased. FTIR, NMR and microanalysis indicated that after the thermal oxidative pre-treatment ether cross-links are present alongside new oxygen containing functional groups such as aldehydes, carboxylic acids and hydroxyl groups. Finally, data obtained from pyrolysis combustion flow calorimetry confirmed that as the number of oxidative cross-links increase, a reduction in the polymer's flammability as assessed by heat release data is observed

    Urinary eicosanoid metabolites in HIV-infected women with central obesity switching to raltegravir: an analysis from the women, integrase, and fat accumulation trial.

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    Chronic inflammation is a hallmark of HIV infection. Eicosanoids reflect inflammation, oxidant stress, and vascular health and vary by sex and metabolic parameters. Raltegravir (RAL) is an HIV-1 integrase inhibitor that may have limited metabolic effects. We assessed urinary F2-isoprostanes (F2-IsoPs), prostaglandin E2 (PGE-M), prostacyclin (PGI-M), and thromboxane B2 (TxB2) in HIV-infected women switching to RAL-containing antiretroviral therapy (ART). Thirty-seven women (RAL = 17; PI/NNRTI = 20) with a median age of 43 years and BMI 32 kg/m(2) completed week 24. TxB2 increased in the RAL versus PI/NNRTI arm (+0.09 versus -0.02; P = 0.06). Baseline PGI-M was lower in the RAL arm (P = 0.005); no other between-arm cross-sectional differences were observed. In the PI/NNRTI arm, 24-week visceral adipose tissue change correlated with PGI-M (rho = 0.45; P = 0.04) and TxB2 (rho = 0.44; P = 0.005) changes, with a trend seen for PGE-M (rho = 0.41; P = 0.07). In an adjusted model, age ā‰„ 50 years (N = 8) was associated with increased PGE-M (P = 0.04). In this randomized trial, a switch to RAL did not significantly affect urinary eicosanoids over 24 weeks. In women continuing PI/NNRTI, increased visceral adipose tissue correlated with increased PGI-M and PGE-M. Older age (ā‰„ 50) was associated with increased PGE-M. Relationships between aging, adiposity, ART, and eicosanoids during HIV-infection require further study

    Mitochondrial function in heart failure: The impact of ischemic and non-ischemic etiology

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    Background Although cardiac mitochondrial dysfunction is associated with heart failure (HF), this is a complex syndrome with two predominant etiologies, ischemic HF (iHF) and non-ischemic HF (niHF), and the exact impact of mitochondrial dysfunction in these two distinct forms of HF is unknown. Methods and results To determine the impact of HF etiology on mitochondrial function, respiration was measured in permeabilized cardiac muscle fibers from patients with iHF (n = 17), niHF (n = 18), and healthy donor hearts (HdH). Oxidative phosphorylation capacity (OXPHOS), assessed as state 3 respiration, fell progressively from HdH to niHF, to iHF (Complex I + II: 54 Ā± 1; 34 Ā± 4; 27 Ā± 3 pmolĀ·sāˆ’ 1Ā·mgāˆ’ 1) as did citrate synthase activity (CSA: 206 Ā± 18; 129 Ā± 6; 82 Ā± 6 nmolĀ·mgāˆ’ 1Ā·mināˆ’ 1). Although still significantly lower than HdH, normalization of OXPHOS by CSA negated the difference in mass specific OXPHOS between iHF and niHF. Interestingly, Complex I state 2 respiration increased progressively from HdH, to niHF, to iHF, whether or not normalized for CSA (0.6 Ā± 0.2; 1.1 Ā± 0.3; 2.3 Ā± 0.3; pmolĀ·mgāˆ’ 1Ā·CSA), such that the respiratory control ratio (RCR), fell in the same manner across groups. Finally, both the total free radical levels (60 Ā± 6; 46 Ā± 4 AU) and level of mitochondrial derived superoxide (1.0 Ā± 0.2; 0.7 Ā± 0.1 AU) were greater in iHF compared to niHF, respectively. Conclusions Thus, the HF-related attenuation in OXPHOS actually appears to be independent of etiology when the lower mitochondrial content of iHF is taken into account. However, these findings provide evidence of deleterious intrinsic mitochondrial changes in iHF, compared to niHF, including greater proton leak, attenuated OXPHOS efficiency, and augmented free radical levels

    Comparison of walking performance over the first 2 minutes and the full 6 minutes of the Six-Minute Walk Test

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    BackgroundAlthough the Six-Minute Walk Test (6MWT), as recommended by the American Thoracic Society, is widely used as a measure of functional endurance, it may not be applicable in some settings and populations. We sought to examine, therefore, performance over the first 2 minutes and the full 6 minutes of the 6MWT. Specifically, we investigated completion rates, distances walked, test-retest reliability, and the relationship between distances walked over the first 2 and the full 6 minutes of the 6MWT.MethodsCommunity-dwelling children and adults age 3-85 years (nā€‰=ā€‰337) were asked to walk back and forth on a 15.24 meter (50 ft) course as far as possible without running over a 6 minute period. Test completion and the distance covered by the participants at 2 and 6 minutes were documented. The reliability of distances covered at 2 and 6 minutes was determined by retesting a subsample of 54 participants 6 to 10 days later. The relationship between distances covered at 2 and 6 minutes was determined for the 330 participants completing the 6MWT.ResultsAll 337 participants completed at least 2 minutes of walking, but 7 children less than 5 years of age ceased walking before 6 minutes had elapsed. For the remaining 330 participants the mean distance walked was 186 meters at 2 minutes and 543 meters at 6 minutes. The distances covered at 2 and 6 minutes were reliable between sessions (intraclass correlation coefficientsā€‰=ā€‰0.888 and 0.917, respectively). The distances covered over 2 and 6 minutes were highly correlated (rā€‰=ā€‰0.968).ConclusionsThe completion rate, values obtained, test-retest reliability, and relationship of the distances walked in 2 and 6 minutes support documentation of 2 minute distance during the 6MWT. The findings also provide support for use of a Two-Minute Walk Test as the endurance component in the Motor Battery of the NIH Toolbox

    High clarity polyurethane laminating adhesives based on poly (propylene glycol). Effect of hard segment on microphase morphology, haze and adhesion

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    Within this publication, the performance of high clarity polyurethane adhesives based on a poly(propylene glycol) soft-phase within a polycarbonate or ethanolamine surface-treated polycarbonate laminate, is described. A series of polyurethanes were prepared, with poly(propylene glycol) used as soft-phase due to the high clarity of this polyol and absence of carbonyl functionality, which allows for hard-phase architecture to be resolved with greater resolution. In total, eight adhesives were synthesised, each contained a different chain-extender formulation to gauge what influence hard-phase architecture had on laminate haze and peel strength. This was investigated using either 4,4-methylene diphenyl diisocyanate or isophorone diisocyanate as hard-phase with trimethylolpropane as the only chain-extender or by including one of the following sterically hindered diols: 2,2-diethyl-1,3-propane diol, 1,3-butane diol or 1,2-proane diol. DSC analysis showed that microphase morphology was strongly influenced by the diisocyanate present, as shown by the degree of phase mixing being greater in methylene diphenyl diisocyanate based formulations when compared with isophorone diisocyanate based. ATR complements this observed difference in microphase morphology, with isophorone diisocyanate based formulations having a greater composition of hydrogen-bonded urethane and urea functionality present within the hard-phase which displays a more phase separated composition. Interestingly, differences in microphase mixing did not have a consistent influence on the peel strength obtained, with only 31% of laminate combinations tested recording a peel strength of < 3 N mm-1 after 18 months. Diol chain-extended formulations based on methylene diphenyl diisocyanate accounted for 25% of these lower values and was a consequence of their poorer process-ability during lamination. This resulted in higher haze values being encountered for both polycarbonate and ethanolamine surface-treated polycarbonate laminates which contained methylene diphenyl diisocyanate based formulations when compared to isophorone diisocyanate based formulations, where all values were < 1.5%

    High clarity poly(caprolactone diol)-based polyurethane adhesives for polycarbonate lamination : effect of isocyanate and chain-extender

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    The development of a high clarity polyurethane adhesive from a crystalline soft-phase capable of bonding untreated and ethanolamine surfaced-treated polycarbonate is described. A series of polyurethanes were prepared, based on poly(caprolactone diol), selected as the soft-phase as its ester-functionalised backbone structure will assist the adhesive performance. A high crystallinity soft-phase, however, will have an adverse effect on the adhesiveā€™s clarity. However, through careful design of the hard-phase architecture, it is possible to address this issue. Eight formulations were synthesised each with a subtly different hard-phase architecture, created using a combination of methylene diphenyl diisocyanate or isophorone diisocyanate with trimethylol propane only or by including the chain-extenders 2,2-diethyl-1,3-propane diol, 1,3-butane diol and 1,2-propane diol. DSC and FTIR data show that having trimethylol propane alone is not sufficient in disrupting soft-phase crystallisation in the methylene diphenyl diisocyanate formulations, and that for total removal of soft-phase crystallisation a diol chain-extender is required to promote phase mixing within the microphase structure. This reduces peel strengths but values remain above 3 N mm-1 on both untreated and ethanolamine treated polycarbonate after 18 months. More importantly, the change to the morphology markedly improves clarity. In contrast, isophorone diisocyanate systems show poor phase mixing even in the presence of the chain-extenders and, although offering good peel strengths, have low clarity

    Urinary Eicosanoid Metabolites in HIV-Infected Women with Central Obesity Switching to Raltegravir: An Analysis from the Women, Integrase, and Fat Accumulation Trial

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    Chronic inflammation is a hallmark of HIV infection. Eicosanoids reflect inflammation, oxidant stress, and vascular health and vary by sex and metabolic parameters. Raltegravir (RAL) is an HIV-1 integrase inhibitor that may have limited metabolic effects. We assessed urinary F2-isoprostanes (F2-IsoPs), prostaglandin E2 (PGE-M), prostacyclin (PGI-M), and thromboxane B2 (TxB2) in HIV-infected women switching to RAL-containing antiretroviral therapy (ART). Thirty-seven women (RAL = 17; PI/NNRTI = 20) with a median age of 43 years and BMI 32ā€‰kg/m2 completed week 24. TxB2 increased in the RAL versus PI/NNRTI arm (+0.09 versus āˆ’0.02; P=0.06). Baseline PGI-M was lower in the RAL arm (P=0.005); no other between-arm cross-sectional differences were observed. In the PI/NNRTI arm, 24-week visceral adipose tissue change correlated with PGI-M (rho=0.45; P=0.04) and TxB2 (rho=0.44; P=0.005) changes, with a trend seen for PGE-M (rho=0.41; P=0.07). In an adjusted model, age ā‰„ 50 years (N=8) was associated with increased PGE-M (P=0.04). In this randomized trial, a switch to RAL did not significantly affect urinary eicosanoids over 24 weeks. In women continuing PI/NNRTI, increased visceral adipose tissue correlated with increased PGI-M and PGE-M. Older age (ā‰„50) was associated with increased PGE-M. Relationships between aging, adiposity, ART, and eicosanoids during HIV-infection require further study

    Evidence of Glycolysis Up-Regulation and Pyruvate Mitochondrial Oxidation Mismatch During Mechanical Unloading of the Failing Human Heart: Implications for Cardiac Reloading and Conditioning

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    This study sought to investigate the effects of mechanical unloading on myocardial energetics and the metabolic perturbation of heart failure (HF) in an effort to identify potential new therapeutic targets that could enhance the unloading-induced cardiac recovery. The authors prospectively examined paired human myocardial tissue procured from 31 advanced HF patients at left ventricular assist device (LVAD) implant and at heart transplant plus tissue from 11 normal donors. They identified increased post-LVAD glycolytic metabolites without a coordinate increase in early, tricarboxylic acid (TCA) cycle intermediates. The increased pyruvate was not directed toward the mitochondria and the TCA cycle for complete oxidation, but instead, was mainly converted to cytosolic lactate. Increased nucleotide concentrations were present, potentially indicating increased flux through the pentose phosphate pathway. Evaluation of mitochondrial function and structure revealed a lack of post-LVAD improvement in mitochondrial oxidative functional capacity, mitochondrial volume density, and deoxyribonucleic acid content. Finally, post-LVAD unloading, amino acid levels were found to be increased and could represent a compensatory mechanism and an alternative energy source that could fuel the TCA cycle by anaplerosis. In summary, the authors report evidence that LVAD unloading induces glycolysis in concert with pyruvate mitochondrial oxidation mismatch, most likely as a result of persistent mitochondrial dysfunction. These findings suggest that interventions known to improve mitochondrial biogenesis, structure, and function, such as controlled cardiac reloading and conditioning, warrant further investigation to enhance unloading-induced reverse remodeling and cardiac recovery
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