981 resultados para BIOMOLECULE-ASSISTED SYNTHESIS
Resumo:
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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Layered doubly hydroxides (LDHs) also known as hydrotalcites or anionic clays are a group of clay minerals that have shown promise for the removal of toxic anions from water through both anion exchange and a process known as the reformation effect. This project has involved the preparation and characterisation of LDH materials as well as the investigation of their ability to remove selected anions from aqueous solutions by the reformation effect. The LDH materials were successfully prepared from magnesium, aluminium, zinc and chromium chloride salts using the co-precipitation method. Samples were characterised using powder X-ray diffraction (XRD) and thermogravimetry (TG) to confirm the presence of LDHs. Powder XRD revealed a characteristic LDH structure for all LDH samples. Thermal Analysis showed decomposition usual occurred through a three or four step process as expected for LDHs. Preliminary investigations of the removal of sulfate, nitrate and fluoride by an Mg/Al LDH were carried out, and the products were characterised using XRD and TG which showed that an LDH material similar to the original hydrotalcite was formed after reformation. A Zn/Al LDH was investigated as a potential sorbent material for the removal of iodine and iodide from water. It was found that the LDH was a suitable adsorbent which is able to remove almost all of the iodine present in the test solutions. Again, the products were characterised by XRD, TG and evolved gas mass spectrometry (EGMS) in an attempt to better understand the iodine removal process. Powder XRD showed successful reformation of the LDH structure and TG/EGMS showed that only a small amount of iodine species were lost during thermal decomposition. Finally, the mineral stichtite a Mg/Cr LDH was successfully synthesised and investigated using XRD, TG and EGMS. Unfortunately, due to lack of time it was not possible to identify any new uses for the mineral stichtite in the current project.
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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?
Resumo:
Flexible design concept is a relatively new trend in airport terminal design which is believed to facilitate the ever changing needs of a terminal. Current architectural design processes become more complex every day because of the introduction of new building technologies where the concept of flexible airport terminal would apparently make the design process even more complex. Previous studies have demonstrated that ever growing aviation industry requires airport terminals to be planned, designed and constructed in such a way that should allow flexibility in design process. In order to adopt the philosophy of ‘design for flexibility’ architects need to address a wide range of differing needs. An appropriate integration of the process models, prior to the airport terminal design process, is expected to uncover the relationships that exist between spatial layout and their corresponding functions. The current paper seeks to develop a way of sharing space adjacency related information obtained from the Business Process Models (BPM) to assist in defining flexible airport terminal layouts. Critical design parameters are briefly investigated at this stage of research whilst reviewing the available design alternatives and an evaluation framework is proposed in the current paper. Information obtained from various design layouts should assist in identifying and defining flexible design matrices allowing architects to interpret and to apply those throughout the lifecycle of the terminal building.
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Murine intestinal intraepithelial lymphocytes (IEL) have been shown to contain subsets of alpha/beta TCR+ and gamma/delta TCR+ T cells that spontaneously produce cytokines such as IFN-gamma and IL-5. We have now determined the nature and cell cycle stage of these cytokine-producing T lymphocytes in EIL by using IFN-gamma- and IL-5-specific ELISPOT assay, cytokine-specific mRNA-cDNA dot-blot hybridization and polymerase chain reaction, and flow cytometry (FACS) for DNA analysis. When CD3+ T cells from IEL of normal C3H/HeN mice were separated into low and high density fractions by discontinuous Percoll gradients, IFN-gamma and IL-5 spot-forming cells were only found in the former population. Analysis of mRNA for these cytokines by both IFN-gamma- and IL-5-specific dot-blot hybridization and polymerase chain reaction revealed that higher levels of message for IFN-gamma and IL-5 were also seen in the low density fraction. However, cell cycle analysis of these two fractions by FACS using propidium iodide showed a similar pattern of cell cycle stages in both low and high density populations (G0 + G1 approximately 96 to 98% and S/G2 + M approximately 2 to 4%). Finally, mRNA from gamma/delta TCR+ and alpha/beta TCR+ T cells in both low and high density fractions of IEL were analyzed for IFN-gamma and IL-5 message by polymerase chain reaction. After 35 cycles of amplification, both gamma/delta TCR+ and alpha/beta TCR+ T cells in the low density fraction expressed higher levels of message for these two cytokines when compared with the high density population. These results have now shown that both gamma/delta and alpha/beta TCR+ IEL can be separated into low and high density subsets and both fractions possess a similar stage of cell cycle. However, only the low density cells (in G1 phase) of both gamma/delta and alpha/beta TCR types possess increased cytokine-specific mRNA and produce the cytokines IFN-gamma and IL-5. Our results suggest that alpha/beta TCR+ and gamma/delta TCR+ IEL can produce cytokines without cell proliferation.
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Zinc oxide (ZnO) nanopyramids were synthesized by a one-pot route in a non-aqueous and surfactantfree environment. The synthesized metal oxide was characterized using SEM, XRD, and TEM to investigate the surface morphology and crystallographic phase of the nanostructures. It was observed that the ZnO nanopyramids were of uniform size and symmetrical, with a hexagonal base and height of ∼100 nm. Gas sensing characterization of the ZnO nanopyramids when deposited as thin-film onto conductometric transducers were performed towards NOx and C2H5OH vapor of different concentrations over a temperature range of 22–350 ◦C. It was observed that the sensors responded towards NO2 (10 ppm) and C2H5OH(250 ppm) analytes best at temperatures of 200 and 260 ◦C with a sensor response of 14.5 and 5.72, respectively. The sensors showed satisfactory sensitivity, repeatability as well as fast response and recovery towards both the oxidizing and the reducing analyte. The good performance was attributed to the low amount of organic impurities, large surface-to-volume ratio and high crystallinity of the solvothermally synthesized ZnO nanopyramids.
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There is a growing number of organizations and universities now utilising e-learning practices in their teaching and learning programs. These systems have allowed for knowledge sharing and provide opportunities for users to have access to learning materials regardless of time and place. However, while the uptake of these systems is quite high, there is little research into the effectiveness of such systems, particularly in higher education. This paper investigates the methods that are used to study the effectiveness of e-learning systems and the factors that are critical for the success of a learning management system (LMS). Five major success categories are identified in this study and explained in depth. These are the teacher, student, LMS design, learning materials and external support.
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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.