984 resultados para photo-assisted degradation


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The presence of colour in raw sugar plays a key role in the marketing strategy of the Australian raw sugar industry. Some sugars are relatively difficult to decolourise during refining and develop colour during storage. A new approach that might result in efficient and cost-effective colour removal during the sugar manufacturing process is the use of an advanced oxidation process (AOP), known as Fenton oxidation, that is, catalytic production of hydroxyl radicals from the decomposition of hydrogen peroxide using ferrous iron. As a first step towards developing this technology, this study determined the composition of colour precursors present in the juice of cane harvested by three different methods. The methods were harvesting cane after burning, harvesting the whole crop with half of the trash extracted and harvesting the whole crop with no trash extracted. The study also investigated the degradation at pH 3, 4 and 5 of a phenolic compound, caffeic acid (3,4–dihydroxycinnamic acid), which is present in sugar cane juice, using both hydrogen peroxide and Fenton’s reagent. The results show that juice expressed from whole crop cane has significantly higher colour than juices expressed from burnt cane. However, the concentrations of phenolic acids were lower in the juices expressed from whole crop cane. The main phenolic acids present in these juices were p-coumaric, vanillic, 2,3–dihydroxybenzoic, gallic and 3,4–dihydroxybenzoic acids. The degradation of caffeic acid significantly improved using Fenton’s reagent in comparison to hydrogen peroxide alone. The Fenton oxidation was optimum at pH 5 when up to ~86 % of caffeic acid degraded within 5 min.

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The presence of colour in raw sugar plays a key role in the marketing strategy of the Australian raw sugar industry. Some sugars are relatively difficult to decolourise during refining and develop colour during storage. A new approach that might result in efficient and cost-effective colour removal during the sugar manufacturing process is the use of an advanced oxidation process (AOP), known as Fenton oxidation, that is, catalytic production of hydroxyl radicals from the decomposition of hydrogen peroxide using ferrous iron. As a first step towards developing this technology, this study determined the composition of colour precursors present in the juice of cane harvested by three different methods. The methods were harvesting cane after burning, harvesting the whole crop with half of the trash extracted and harvesting the whole crop with no trash extracted. The study also investigated the degradation at pH 3, 4 and 5 of a phenolic compound, caffeic acid (3,4–dihydroxycinnamic acid), which is present in sugar cane juice, using both hydrogen peroxide and Fenton’s reagent. The results show that juice expressed from whole crop cane has significantly higher colour than juices expressed from burnt cane. However, the concentrations of phenolic acids were lower in the juices expressed from whole crop cane. The main phenolic acids present in these juices were p-coumaric, vanillic, 2,3–dihydroxybenzoic, gallic and 3,4–dihydroxybenzoic acids. The degradation of caffeic acid significantly improved using Fenton’s reagent in comparison to hydrogen peroxide alone. The Fenton oxidation was optimum at pH 5 when up to ~86% of caffeic acid degraded within 5 min.

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On 1 January 2010, the Assisted Reproductive Treatment Act 2008 (Vic) came into force. The legislation was the outcome of a detailed review and consultation process undertaken by the Victorian Law Reform Commission. Arguably, the change to the regulatory framework represents a significant shift in policy compared to previous regulatory approaches on this topic in Victoria. This article considers the impact of the new legislation on eligibility for reproductive treatments, focusing on the accessibility of such services for the purpose of creating a “saviour sibling”. It also highlights the impact of the Victorian regulatory body’s decision to abolish its regulatory policies on preimplantation genetic diagnosis and preimplantation tissue-typing, concluding that the regulatory approach in relation to these latter issues is similar to other Australian jurisdictions where such practices are not addressed by a statutory framework.

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Blends of lignin and poly(hydroxybutyrate) (PHB) were obtained by melt extrusion. They were buried in a garden soil for up to 12 months, and the extent and mechanism of degradation were investigated by gravimetric analysis, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and Fourier transform infra-red spectroscopy (FTIR) over the entire range of compositions. The PHB films were disintegrated and lost 45 wt% of mass within 12 months. This value dropped to 12 wt% of mass when only 10 wt% of lignin was present, suggesting that lignin both inhibited and slowed down the rate of PHB degradation. TGA and DSC indicated structural changes, within the lignin/PHB matrix, with burial time, while FTIR results confirmed the fragmentation of the PHB polymer. XPS revealed an accumulation of biofilms on the surface of buried samples, providing evidence of a biodegradation mechanism. Significant surface roughness was observed with PHB films due to microbial attack caused by both loosely and strongly associated micro-organisms. The presence of lignin in the blends may have inhibited the colonisation of the micro-organisms and caused the blends to be more resistant to microbial attack. Analysis suggested that lignin formed strong hydrogen bonds with PHB in the buried samples and it is likely that the rate of breakdown of PHB is reduced, preventing rapid degradation of the blends.

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Nutrition interventions in the form of both self-management education and individualised diet therapy are considered essential for the long-term management of type 2 diabetes mellitus (T2DM). The measurement of diet is essential to inform, support and evaluate nutrition interventions in the management of T2DM. Barriers inherent within health care settings and systems limit ongoing access to personnel and resources, while traditional prospective methods of assessing diet are burdensome for the individual and often result in changes in typical intake to facilitate recording. This thesis investigated the inclusion of information and communication technologies (ICT) to overcome limitations to current approaches in the nutritional management of T2DM, in particular the development, trial and evaluation of the Nutricam dietary assessment method (NuDAM) consisting of a mobile phone photo/voice application to assess nutrient intake in a free-living environment with older adults with T2DM. Study 1: Effectiveness of an automated telephone system in promoting change in dietary intake among adults with T2DM The effectiveness of an automated telephone system, Telephone-Linked Care (TLC) Diabetes, designed to deliver self-management education was evaluated in terms of promoting dietary change in adults with T2DM and sub-optimal glycaemic control. In this secondary data analysis independent of the larger randomised controlled trial, complete data was available for 95 adults (59 male; mean age(±SD)=56.8±8.1 years; mean(±SD)BMI=34.2±7.0kg/m2). The treatment effect showed a reduction in total fat of 1.4% and saturated fat of 0.9% energy intake, body weight of 0.7 kg and waist circumference of 2.0 cm. In addition, a significant increase in the nutrition self-efficacy score of 1.3 (p<0.05) was observed in the TLC group compared to the control group. The modest trends observed in this study indicate that the TLC Diabetes system does support the adoption of positive nutrition behaviours as a result of diabetes self-management education, however caution must be applied in the interpretation of results due to the inherent limitations of the dietary assessment method used. The decision to use a close-list FFQ with known bias may have influenced the accuracy of reporting dietary intake in this instance. This study provided an example of the methodological challenges experienced with measuring changes in absolute diet using a FFQ, and reaffirmed the need for novel prospective assessment methods capable of capturing natural variance in usual intakes. Study 2: The development and trial of NuDAM recording protocol The feasibility of the Nutricam mobile phone photo/voice dietary record was evaluated in 10 adults with T2DM (6 Male; age=64.7±3.8 years; BMI=33.9±7.0 kg/m2). Intake was recorded over a 3-day period using both Nutricam and a written estimated food record (EFR). Compared to the EFR, the Nutricam device was found to be acceptable among subjects, however, energy intake was under-recorded using Nutricam (-0.6±0.8 MJ/day; p<0.05). Beverages and snacks were the items most frequently not recorded using Nutricam; however forgotten meals contributed to the greatest difference in energy intake between records. In addition, the quality of dietary data recorded using Nutricam was unacceptable for just under one-third of entries. It was concluded that an additional mechanism was necessary to complement dietary information collected via Nutricam. Modifications to the method were made to allow for clarification of Nutricam entries and probing forgotten foods during a brief phone call to the subject the following morning. The revised recording protocol was evaluated in Study 4. Study 3: The development and trial of the NuDAM analysis protocol Part A explored the effect of the type of portion size estimation aid (PSEA) on the error associated with quantifying four portions of 15 single foods items contained in photographs. Seventeen dietetic students (1 male; age=24.7±9.1 years; BMI=21.1±1.9 kg/m2) estimated all food portions on two occasions: without aids and with aids (food models or reference food photographs). Overall, the use of a PSEA significantly reduced mean (±SD) group error between estimates compared to no aid (-2.5±11.5% vs. 19.0±28.8%; p<0.05). The type of PSEA (i.e. food models vs. reference food photograph) did not have a notable effect on the group estimation error (-6.7±14.9% vs. 1.4±5.9%, respectively; p=0.321). This exploratory study provided evidence that the use of aids in general, rather than the type, was more effective in reducing estimation error. Findings guided the development of the Dietary Estimation and Assessment Tool (DEAT) for use in the analysis of the Nutricam dietary record. Part B evaluated the effect of the DEAT on the error associated with the quantification of two 3-day Nutricam dietary records in a sample of 29 dietetic students (2 males; age=23.3±5.1 years; BMI=20.6±1.9 kg/m2). Subjects were randomised into two groups: Group A and Group B. For Record 1, the use of the DEAT (Group A) resulted in a smaller error compared to estimations made without the tool (Group B) (17.7±15.8%/day vs. 34.0±22.6%/day, p=0.331; respectively). In comparison, all subjects used the DEAT to estimate Record 2, with resultant error similar between Group A and B (21.2±19.2%/day vs. 25.8±13.6%/day; p=0.377 respectively). In general, the moderate estimation error associated with quantifying food items did not translate into clinically significant differences in the nutrient profile of the Nutricam dietary records, only amorphous foods were notably over-estimated in energy content without the use of the DEAT (57kJ/day vs. 274kJ/day; p<0.001). A large proportion (89.6%) of the group found the DEAT helpful when quantifying food items contained in the Nutricam dietary records. The use of the DEAT reduced quantification error, minimising any potential effect on the estimation of energy and macronutrient intake. Study 4: Evaluation of the NuDAM The accuracy and inter-rater reliability of the NuDAM to assess energy and macronutrient intake was evaluated in a sample of 10 adults (6 males; age=61.2±6.9 years; BMI=31.0±4.5 kg/m2). Intake recorded using both the NuDAM and a weighed food record (WFR) was coded by three dietitians and compared with an objective measure of total energy expenditure (TEE) obtained using the doubly labelled water technique. At the group level, energy intake (EI) was under-reported to a similar extent using both methods, with the ratio of EI:TEE was 0.76±0.20 for the NuDAM and 0.76±0.17 for the WFR. At the individual level, four subjects reported implausible levels of energy intake using the WFR method, compared to three using the NuDAM. Overall, moderate to high correlation coefficients (r=0.57-0.85) were found across energy and macronutrients except fat (r=0.24) between the two dietary measures. High agreement was observed between dietitians for estimates of energy and macronutrient derived for both the NuDAM (ICC=0.77-0.99; p<0.001) and WFR (ICC=0.82-0.99; p<0.001). All subjects preferred using the NuDAM over the WFR to record intake and were willing to use the novel method again over longer recording periods. This research program explored two novel approaches which utilised distinct technologies to aid in the nutritional management of adults with T2DM. In particular, this thesis makes a significant contribution to the evidence base surrounding the use of PhRs through the development, trial and evaluation of a novel mobile phone photo/voice dietary record. The NuDAM is an extremely promising advancement in the nutritional management of individuals with diabetes and other chronic conditions. Future applications lie in integrating the NuDAM with other technologies to facilitate practice across the remaining stages of the nutrition care process.

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The main factors affecting environmental sensitivity to degradation are soil, vegetation, climate and management, through either their intrinsic characteristics or by their interaction on the landscape. Different levels of degradation risks may be observed in response to particular combinations of the aforementioned factors. For instance, the combination of inappropriate management practices and intrinsically weak soil conditions will result in a severe degradation of the environment, while the combination of the same type of management with better soil conditions may lead to negligible degradation.The aim of this study was to identify factors and their impact on land degradation processes in three areas of the Basilicata region (southern Italy) using a procedure that couples environmental indices, GIS and crop-soil simulation models. Areas prone to desertification were first identified using the Environmental Sensitive Areas (ESA) procedure. An analysis for identifying the weight that each of the contributing factor (climate, soil, vegetation, management) had on the ESA was carried out using GIS techniques. The SALUS model was successfully executed to identify the management practices that could lead to better soil conditions to enhance land use sustainability. The best management practices were found to be those that minimized soil disturbance and increased soil organic carbon. Two alternative scenarios with improved soil quality and subsequently improving soil water holding capacity were used as mitigation measures. The ESA were recalculated and the effects of the mitigation measures suggested by the model were assessed. The new ESA showed a significant reduction on land degradation.

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Folate is essential for human health in the prevention of megaloblastic anaemia and neural tube birth defects as well as roles in cardiovascular disease and cancer. Therefore research into environmental factors that may impact folate status, such as solar ultraviolet radiation, is of great health significance. In vitro studies have shown that ultraviolet (UV) radiation can degrade folate and folic acid in human blood and this has been confirmed in several human studies. Despite these findings, there is a dearth of epidemiological research into investigating the relationship between folate status and the links to solar UV exposure.

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The first effective life extension technologies might well become available within the next few years. Experts from the University of Queensland, Australia, explore the possible public reaction to these therapies and the ethical and social concerns they raise, drawing on the experience of assisted reproduction technologies

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Objective To examine the extent to which the odds of birth, pregnancy, or adverse birth outcomes are higher among women aged 28 to 36 years who use fertility treatment compared with untreated women. Design Prospective, population-based. Setting Not applicable. Patient(s) Participants in the ALSWH born in 1973 to 1978 who reported on their infertility and use of in vitro fertilization (IVF) or ovulation induction (OI). Intervention(s) Postal survey questionnaires administered as part of ALSWH. Main Outcome Measure(s) Among women treated with IVF or OI and untreated women, the odds of birth outcomes estimated by use of adjusted logistic regression modeling. Result(s) Among 7,280 women, 18.6% (n = 1,376) reported infertility. Half (53.0%) of the treated women gave birth compared with 43.8% of untreated women. Women with prior parity were less likely to use IVF compared with nulliparous women. Women using IVF or OI, respectively, were more likely to have given birth after treatment or be pregnant compared with untreated women. Women using IVF or OI were as likely to have ectopic pregnancies, stillbirths, or premature or low birthweight babies as untreated women. Conclusion(s) More than 40% of women aged 28–36 years reporting a history of infertility can achieve births without using treatment, indicating they are subfertile rather than infertile.

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Assisted Reproductive Technologies (ART) offer a wide range of techniques that have the potential to augment efforts to conserve and manage endangered amphibians and improve wild and captive population numbers. Gametes and tissues of species nearing endangered or extinct status can be cryopreserved and stored in gene banks, to provide material that can be utilised in the future as ART methods are refined. The Spotted Grass Frog, Limnodynastes tasmaniensis, is an abundant amphibian species in South-Eastern Australia of the family Myobatrachidae, that is suitable for the development of ART systems that can be applied to the threatened and endangered myobatrachid and other amphibian species native to Australia. The aim of this study was to advance the understanding of ovulation, fertilisation and embryo nic development of Lim. tasmaniensis and in vitro manipulations of reproduction and development for use in the development of advanced ART procedures such as intracytoplasmic spermatozoon injection (ICSI), androgenesis and nuclear transfer. Ovulation in amphibians can be induced by protocols utilising natural or synthetic hormones. All protocols tested on Lim. tasmaniensis in this study required two injections and the most effective protocols continued to require a first injection of pituitary extracts to induce ovulation. The second injection was, however, successfully replaced by synthetic chorionic gonadotrophin at a threshold dosage of 100 iu and halved the number of cane toads required to source the pituitaries. A combination of LHRH and Pimozide offered a less effective protocol, that did not require the use of pituitary extracts, and avoided the risk of pathogen transfer associated with unsterilised pituitary extracts. Unfertilised eggs of Lim. tasmaniensis were exposed to media of various osmolalities to determine media effects on eggs and their surrounding jelly layers that might impact on egg viability and fertilisability. Osmolality had no effect upon the egg diameter, however, rapid swelling of the jelly layers occurred within 15 minutes of exposure to various media treatments and plateaued from 30-90 minutes without further expansion. Swelling of the jelly layers was increased in hypotonic media (2.5% SAR, H2O) and minimised in the isotonic media (100% SAR). The optimal conditions for the culture of Lim. tasmaniensis eggs were identified as a holding media of 100% SAR, followed by a medium change to 2.5% SAR at insemination. This sequence of media minimised the rate of swelling of the jelly layers prior to contact with the spermatozoa, and maximised the activation of spermatozoa and eggs throughout fertilisation and embryonic development. Embryos of Lim. tasmaniensis were cultured at four temperatures (13 C, 17 C, 23 C and 29 C), to determine the effect of temperature on cleavage and embryonic development rates. Embryonic development progressed through a sequence of stages that were not altered by changes in temperature. However cleavage rates were affected by changes in temperature as compared with normal embryonic growth at 23 C. Embryonic development was suspended at the lowest temperature (13 C) while embryonic viability was maintained. A moderate decrease in temperature (17 C) slowed cleavage, while the highest temperature (29 C) increased the cleavage rate, but decreased the embryo survival. Rates of embryonic development can be manipulated by changes in temperature and this method can be used to source blastomeres of a specific size/stage at a predetermined age or halt cleavage at specific stages for embryos or embryo derived cells to be included in ART procedures. This study produced the first report of the application of Intracytoplasmic Spermatozoon Injection (ICSI) in an Australian amphibian. Eggs that were activated by microinjection with a single spermatozoon (n=50) formed more deep, but abnormal, cleavage furrows post-injection (18/50, 36%), than surface changes (12/50, 24%). This result is in contrast to eggs injected without a spermatozoon (n=42), where the majority of eggs displayed limited surface changes (36/42, 86%), and few deep, abnormal furrows (3/42, 7%). Three advanced embryos (3/50, 6%) were produced by ICSI that developed to various stages within the culture system. Technical difficulties were encountered that prevented the generation of any metamorphs from ICSI tadpoles. Nevertheless, when these blocks to ICSI are overcome, the ICSI procedure will be both directly useful as an ART procedure in its own right, and the associated refinement of micromanipulation procedures will assist in the development of other ART procedures in Lim. tasmaniensis. A greater understanding of basic reproductive and developmental biology in Lim. tasmaniensis would greatly facilitate refinement of fertilisation by ICSI. Assisted Reproductive Technologies, in conjunction with gene banks may in the future regenerate extinct amphibian species, and assist in the recovery of declining amphibian populations nationally and worldwide.

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The purpose of this paper is to provide a basis from which to start an informed and rational dialogue in Australia about voluntary euthanasia (VE) and assisted suicide (AS). It does this by seeking to chart the broad landscape of issues that can be raised as relevant to how this conduct should be regulated by the law. It is not our purpose to persuade. Rather, we have attempted to address the issues as neutrally as possible and to canvass both sides of the argument in an even-handed manner. We hope that this exercise places the reader in a position to consider the question posed by this paper: How should Australia regulate voluntary euthanasia and assisted suicide? In line with the approach taken in the paper, this question does not take sides in the debate. It simply asks how VE and AS should be regulated, acknowledging that both prohibition and legalisation of such conduct involve regulation. We begin by considering the wider legal framework that governs end of life decision-making. Decisions to withhold or withdraw life-sustaining treatment that result in a person’s death can be lawful. This could be because, for example, a competent adult refuses such treatment. Alternatively, stopping or not providing treatment can be lawful when it is no longer in a person’s best interests to receive it. The law also recognises that appropriate palliative care should not attract criminal responsibility. By contrast, VE and AS are unlawful in Australia and could lead to prosecution for crimes such as murder, manslaughter or aiding and abetting suicide. But this is not to say that such conduct does not occur in practice. Indeed, there is a body of evidence that VE and AS occur in Australia, despite them being unlawful. There have been repeated efforts to change the law in this country, mainly by the minor political parties. However, apart from a brief period when VE and AS was lawful in the Northern Territory, these attempts to reform the law have been unsuccessful. The position is different in a small but increasing number of jurisdictions overseas where such conduct is lawful. The most well known is the Netherlands but there are also statutory regimes that regulate VE and/or AS in Belgium and Luxembourg in Europe, and Oregon and Washington in the United States. A feature of these legislative models is that they incorporate review or oversight processes that enable the collection of data about how the law is being used. As a result, there is a significant body of evidence that is available for consideration to assess the operation of the law in these jurisdictions and some of this is considered briefly here. Assisting a suicide, if done for selfless motives, is also legal in Switzerland, and this has resulted in what has been referred to as ‘euthanasia tourism’. This model is also considered. The paper also identifies the major arguments in favour of, and against, legalisation of VE and AS. Arguments often advanced in favour of law reform include respect for autonomy, that public opinion favours reform, and that the current law is incoherent and discriminatory. Key arguments against legalising VE and AS point to the sanctity of life, concerns about the adequacy and effectiveness of safeguards, and a ‘slippery slope’ that will allow euthanasia to occur for minors or for adults where it is not voluntary. We have also attempted to step beyond these well trodden and often rehearsed cases ‘for and against’. To this end, we have identified some ethical values that might span both sides of the debate and perhaps be the subject of wider consensus. We then outline a framework for considering the issue of how Australia should regulate VE and AS. We begin by asking whether such conduct should be criminal acts (as they presently are). If VE and AS should continue to attract criminal responsibility, the next step is to enquire whether the law should punish such conduct more or less than is presently the case, or whether the law should stay the same. If a change is favoured as to how the criminal law punishes VE and AS, options considered include sentencing reform, creating context-specific offences or developing prosecutorial guidelines for how the criminal justice system deals with these issues. If VE and AS should not be criminal acts, then questions arise as to how and when they should be permitted and regulated. Possible elements of any reform model include: ensuring decision-making is competent and voluntary; ascertaining a person’s eligibility to utilise the regime, for example, whether it depends on him or her having a terminal illness or experiencing pain and suffering; and setting out processes for how any decision must be made and evidenced. Options to bring about decriminalisation include challenging the validity of laws that make VE and AS unlawful, recognising a defence to criminal prosecution, or creating a statutory framework to regulate the practice. We conclude the paper where we started: with a call for rational and informed consideration of a difficult and sensitive issue. How should Australia regulate voluntary euthanasia and assisted suicide?

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This paper invites consideration of how Australia should regulate voluntary euthanasia and assisted suicide. We have attempted to pose this question as neutrally as possible, acknowledging that both prohibition and legalisation of such conduct involve decisions about regulation. We begin by charting the wider field of law at the end of life, before considering the repeated, but ultimately unsuccessful, attempts at law reform in Australia. The situation in Australia is contrasted with permissive jurisdictions overseas where voluntary euthanasia and/or assisted suicide are lawful. We consider the arguments for and against legalisation of such conduct along with the available empirical evidence as to what happens in practice both in Australia and overseas. The paper concludes by outlining a framework for deliberating on how Australia should regulate voluntary euthanasia and assisted suicide. We ask a threshold question of whether such conduct should be criminal acts (as they presently are), the answer to which then leads to a range of possible regulatory options.