1000 resultados para 290699 Chemical Engineering not elsewhere classified
Resumo:
The article analyzes the representation of disability in Australian national cinema. Disability has been an enduring topic in Australian films and it has got occasional mentions in film and cultural criticism. An important pioneering treatment in this field is film critic Elizabeth Ferrier's examination of the trope of creative disabilities. Ferrier draws attention to disability in Australian film. She provides a stimulating and nuanced reading in light of the thematics of Australian cultural anxieties. "My One Legged Dream Lover," is one of the few productions that features a disabled lead character, Kath Duncan, played by disabled performer, Kath Duncan.
Resumo:
Inorganic arsenic compounds are known carcinogens. The human epidemiologic evidence of arsenic-induced skin, lung, and bladder cancers is strong. However, the evidence of arsenic carcinogenicity in animals is very limited. Lack of a suitable animal model until recent years has inhibited studies of the mechanism of arsenic carcinogenesis. The toxicity and bioavailability of arsenic depend on its solubility and chemical forms. Therefore, it is critical to be able to measure arsenic speciation accurately and reliably. However, speciation of arsenic in more complex matrices remains a real challenge. There are tens of millions of people who are being exposed to excessive levels of arsenic in the drinking water alone. The source of contamination is mainly of natural origin and the mass poisoning is occurring worldwide, particularly in developing countries. Chronic arsenicosis resulting in cancer and non-cancer diseases will impact significantly on the public health systems in their respective countries. Effective watershed management and remediation technologies in addition to medical treatment are urgently needed in order to avoid what has been regarded as the largest calamity of chemical poisoning in the world.
Ship arrest and the admiralty jurisdiction of Australia and South Africa: too far or not far enough?
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The effects of acetate and propionate on the performance of a recently proposed and characterized photosynthetic biological sulfide removal system have been investigated with a view to predicting this concept's suitability for removing sulfide from wastewater undergoing or having undergone anaerobic treatment. The concept relies on substratum-irradiated biofilms dominated by green sulfur bacteria (GSB), which are supplied with radiant energy in the band 720 - 780 nm. A model reactor was fed for 7 months with a synthetic wastewater free of volatile fatty acids (VFAs), after which time intermittent dosing of the wastewater with acetate or propionate was begun. Such dosing suppressed the areal net sulfide removal rate by similar to50%, and caused the principal net product of sulfide removal to switch from sulfate to elemental-S. Similarly suppressed values of this rate were observed when the wastewater was dosed continuously with acetate, and this rate was not significantly affected by changes in the concentration of ammonia-N in the feed. The main net product of sulfide removal was again elemental-S, which was scarcely released into the liquid, however. Sulfate reduction and sulfur reduction were observed when the light supply was interrupted and were inferred to be occurring within the irradiated biofilm. A preexisting conceptual model of the biofilm was augmented with both of these reductive processes, and this augmented model was shown to account for most of the observed effects of VFA dosing. The implications of these findings for the practicality of the technology are considered. (C) 2004 Wiley Periodicals, Inc.
Resumo:
To evaluate the long term sustainability of water withdrawals in the United States, a county level analysis of the availability of renewable water resources was conducted, and the magnitudes of human withdrawals from surface water and ground water sources and the stored water requirements during the warmest months of the year were evaluated. Estimates of growth in population and electricity generation were then used to estimate the change in withdrawals assuming that the rates of water use either remain at their current levels (the business as usual scenario) or that they exhibit improvements in efficiency at the same rate as observed over 1975 to 1995 (the improved efficiency scenario). The estimates show several areas, notably the Southwest and major metropolitan areas throughout the United States, as being likely to have significant new storage requirements with the business-as-usual scenario, under the condition of average water availability. These new requirements could be substantially eliminated under the improved efficiency scenario, thus indicating the importance of water use efficiency in meeting future requirements. The national assessment identified regions of potential water sustainability concern; these regions can be the subject of more targeted data collection and analyses in the future.
Resumo:
Of those explants tested, immature zygotic embryo tissues proved to be the best for initiating callus with potential for somatic embryogenesis. Slicing of this tissue and use of the central sections (near to and including the meristematic tissue) gave the best embryogenic response. Slices that were placed under illumination necrosed more rapidly and to a greater degree than those incubated in the dark. Explant slice necrosis could be prevented or severely retarded by the addition of activated charcoal into the medium. Washing the explants for short periods of time prior to culture was also found to improve callus production. Prolonged washing resulted in low rates of callus production. In an attempt to prevent ethylene accumulation in the culture vessel headspace, AVG, an ethylene biosynthesis inhibitor and STS, a chemical which reduces the physiological action of ethylene, were successfully used to promote somatic embryogenesis. Spermidine, putrescine and spermine, polyamines that are known to delay plant senescence and promote somatic embryogenesis in some plant species, enhanced the rate of somatic embryogenesis when they were introduced into the callus induction medium. The use of polyethylene glycol in combination with abscisic acid helped promote somatic embryo formation and maturation as well as the subsequent formation of plantlets. The use of all of these improvements together has created a new and improved protocol for coconut somatic embryogenesis. This new protocol puts significant emphasis on improving the in vitro ecology of the explant, callus and somatic embryogenic tissues.
Resumo:
Ginger (Zingiber officinale, Roscoe), a monocotyledonous, sterile cultigen, is widely used as a spice, flavoring agent, and herbal medicine. The pungency of fresh ginger is due to a series of homologous phenolic ketones of which [6]-gingerol is the major one. The gingerols are thermally unstable and can be converted to their corresponding shogaols, which are present in dried ginger, Fresh rhizomes of 17 clones of Australian ginger, including commercial cultivars and experimental tetraploid clones, were assayed by HPLC for gingerols and shogaols. [6]-Gingerol was identified as the major pungent phenolic compound in all samples, while [8]- and [10]-gingerol occurred in lower concentrations. One cultivar known as Jamaican contained the highest concentrations of all three gingerols and was the most pungent of the clones analyzed. Gingerols were stable in ethanolic solution over a 5-month period when stored at 4 degrees C. Shogaols were not identified in the extracts prepared from fresh rhizomes at ambient temperature, confirming that these compounds are not native constituents of fresh ginger, In contrast to previous findings, this study did not find significant differences in gingerol concentrations between the tetraploid clones and their parent diploid cultivar.
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The flavivirus West Nile virus (WNV) has spread rapidly throughout the world in recent years causing fever, meningitis, encephalitis, and fatalities. Because the viral protease NS2B/NS3 is essential for replication, it is attracting attention as a potential therapeutic target, although there are currently no antiviral inhibitors for any flavivirus. This paper focuses on elucidating interactions between a hexapeptide substrate (Ae-KPGLKR-p-nitroanilide) and residues at S1 and S2 in the active site of WNV protease by comparing the catalytic activities of selected mutant recombinant proteases in vitro. Homology modeling enabled the predictions of key mutations in VWNV NS3 protease at S1 (V115A/F, D129A/ E/N, S135A, Y150A/F, S160A, and S163A) and S2 (N152A) that might influence substrate recognition and catalytic efficiency. Key conclusions are that the substrate P1 Arg strongly interacts with S1 residues Asp-129, Tyr-150, and Ser-163 and, to a lesser extent, Ser-160, and P2 Lys makes an essential interaction with Asn-152 at S2. The inferred substrate-enzyme interactions provide a basis for rational protease inhibitor design and optimization. High sequence conservation within flavivirus proteases means that this study may also be relevant to design of protease inhibitors for other flavivirus proteases.
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This paper explores potential for the RAMpage memory hierarchy to use a microkernel with a small memory footprint, in a specialized cache-speed static RAM (tightly-coupled memory, TCM). Dreamy memory is DRAM kept in low-power mode, unless referenced. Simulations show that a small microkernel suits RAMpage well, in that it achieves significantly better speed and energy gains than a standard hierarchy from adding TCM. RAMpage, in its best 128KB L2 case, gained 11% speed using TCM, and reduced energy 14%. Equivalent conventional hierarchy gains were under 1%. While 1MB L2 was significantly faster against lower-energy cases for the smaller L2, the larger SRAM's energy does not justify the speed gain. Using a 128KB L2 cache in a conventional architecture resulted in a best-case overall run time of 2.58s, compared with the best dreamy mode run time (RAMpage without context switches on misses) of 3.34s, a speed penalty of 29%. Energy in the fastest 128KB L2 case was 2.18J vs. 1.50J, a reduction of 31%. The same RAMpage configuration without dreamy mode took 2.83s as simulated, and used 2.39J, an acceptable trade-off (penalty under 10%) for being able to switch easily to a lower-energy mode.
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The mechanical behavior of the vertebrate skull is often modeled using free-body analysis of simple geometric structures and, more recently, finite-element (FE) analysis. In this study, we compare experimentally collected in vivo bone strain orientations and magnitudes from the cranium of the American alligator with those extrapolated from a beam model and extracted from an FE model. The strain magnitudes predicted from beam and FE skull models bear little similarity to relative and absolute strain magnitudes recorded during in vivo biting experiments. However, quantitative differences between principal strain orientations extracted from the FE skull model and recorded during the in vivo experiments were smaller, and both generally matched expectations from the beam model. The differences in strain magnitude between the data sets may be attributable to the level of resolution of the models, the material properties used in the FE model, and the loading conditions (i.e., external forces and constraints). This study indicates that FE models and modeling of skulls as simple engineering structures may give a preliminary idea of how these structures are loaded, but whenever possible, modeling results should be verified with either in vitro or preferably in vivo testing, especially if precise knowledge of strain magnitudes is desired. (c) 2005 Wiley-Liss, Inc.
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Background: Methodological challenges such as recruitment problems and participant burden make clinical trials in palliative care difficult. In 2001-2004, two community-based randomized controlled trials (RCTs) of case conferences in palliative care settings were independently conducted in Australia-the Queensland Case Conferences trial (QCC) and the Palliative Care Trial (PCT). Design: A structured comparative study of the QCC and PCT was conducted, organized by known practical and organizational barriers to clinical trials in palliative care. Results: Differences in funding dictated study designs and recruitment success; PCT had 6 times the budget of QCC. Sample size attainment. Only PCT achieved the sample size goal. QCC focused on reducing attrition through gatekeeping while PCT maximized participation through detailed recruitment strategies and planned for significant attrition. Testing sustainable interventions. QCC achieved a higher percentage of planned case conferences; the QCC strategy required minimal extra work for clinicians while PCT superimposed conferences on normal work schedules. Minimizing participant burden. Differing strategies of data collection were implemented to reduce participant burden. QCC had short survey instruments. PCT incorporated all data collection into normal clinical nursing encounters. Other. Both studies had acceptable withdrawal rates. Intention-to-treat analyses are planned. Both studies included substudies to validate new outcome measures. Conclusions: Health service interventions in palliative care can be studied using RCTs. Detailed comparative information of strategies, successes and challenges can inform the design of future trials. Key lessons include adequate funding, recruitment focus, sustainable interventions, and mechanisms to minimize participant burden.
Resumo:
Neutrophilic lung inflammation is an essential component of host defense against diverse eukaryotic and prokaryotic pathogens, but in chronic inflammatory lung diseases, such as chronic obstructive lung disease (COPD), severe asthma, cystic fibrosis, and bronchiolitis, it may damage the host. Glucocorticosteroids are widely used in these conditions and in their infectious exacerbations; however, the clinical efficacy of steroids is disputed. In this study, we used a proteomic approach to identify molecules contributing to neutrophilic inflammation induced by transnasal administration of lipopolysaccharide (LPS) that were also resistant to the potent glucocorticosteroid dexamethasone (Dex). We confirmed that Dex was biologically active at both the transcript (suppression of GM-CSF and TNFalpha transcripts) and protein levels (induction of lipocortin) and used 2D-PAGE/MALDI-TOF to generate global expression profiles, identifying six LPS-induced proteins that were Dex resistant. Of these, S100A8, a candidate neutrophil chemotactic factor, was profiled in detail. Steroid refractory S100A8 expression was highly abundant, transcriptionally regulated, secreted into lung lavage fluid and immunohistochemically localized to tissue infiltrating neutrophils. However, in marked contrast to other vascular beds, neutralizing antibodies to S100A8 had only a weak anti-neutrophil recruitment effect and antibodies against the related S100A9 were ineffective. These data highlight the need for extensive in vivo profiling of proteomically identified candidate molecules and demonstrates that S100A8, despite its abundance, resistance to steroids and known chemotactic activity, is unlikely to be an important determinant of LPS-induced neutrophilic lung inflammation in vivo.
Resumo:
We provide an abstract command language for real-time programs and outline how a partial correctness semantics can be used to compute execution times. The notions of a timed command, refinement of a timed command, the command traversal condition, and the worst-case and best-case execution time of a command are formally introduced and investigated with the help of an underlying weakest liberal precondition semantics. The central result is a theory for the computation of worst-case and best-case execution times from the underlying semantics based on supremum and infimum calculations. The framework is applied to the analysis of a message transmitter program and its implementation. (c) 2005 Elsevier B.V. All rights reserved.