8,779 research outputs found

    Human cloning in film: horror, ambivalence, hope

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    Fictional filmic representations of human cloning have shifted in relation to the 1997 announcement of the birth of Dolly the cloned sheep, and since therapeutic human cloning became a scientific practice in the early twentieth century. The operation and detail of these shifts can be seen through an analysis of the films The Island (2005) and Aeon Flux (2005). These films provide a site for the examination of how these changes in human cloning from fiction to practice, and from horror to hope, have been represented and imagined, and how these distinctions have operated visually in fiction, and in relation to genre

    The nucleotide sequence of a human immnnoglobulin C-gamma-1 gene

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    We report the nucleotide sequence of a gene encoding the constant region of a human immnnoglobulin γ1 heavy chain (Cγ1). A comparison of this sequence with those of the Cγ2 and Cγ4 genes reveals that these three human Cγ genes share considerable homology in both coding and noncoding regions. The nucleotide sequence differences indicate that these genes diverged from one another approximately 6–8 million years ago. An examination of hinge exons shows that these coding regions have evolved more rapidly than any other areas of the Cγ genes in terms of both base substitution and deletion–insertion events. Coding sequence diversity also is observed in areas of CH domains which border the hinge

    Second Thoughts: How Human Cloning Can Promote Human Dignity

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    Transmission of mitochondrial DNA following assisted reproduction and nuclear transfer

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    Review of the articleMitochondria are the organelles responsible for producing the majority of a cell's ATP and also play an essential role in gamete maturation and embryo development. ATP production within the mitochondria is dependent on proteins encoded by both the nuclear and the mitochondrial genomes, therefore co-ordination between the two genomes is vital for cell survival. To assist with this co-ordination, cells normally contain only one type of mitochondrial DNA (mtDNA) termed homoplasmy. Occasionally, however, two or more types of mtDNA are present termed heteroplasmy. This can result from a combination of mutant and wild-type mtDNA molecules or from a combination of wild-type mtDNA variants. As heteroplasmy can result in mitochondrial disease, various mechanisms exist in the natural fertilization process to ensure the maternal-only transmission of mtDNA and the maintenance of homoplasmy in future generations. However, there is now an increasing use of invasive oocyte reconstruction protocols, which tend to bypass mechanisms for the maintenance of homoplasmy, potentially resulting in the transmission of either form of mtDNA heteroplasmy. Indeed, heteroplasmy caused by combinations of wild-type variants has been reported following cytoplasmic transfer (CT) in the human and following nuclear transfer (NT) in various animal species. Other techniques, such as germinal vesicle transfer and pronuclei transfer, have been proposed as methods of preventing transmission of mitochondrial diseases to future generations. However, resulting embryos and offspring may contain mtDNA heteroplasmy, which itself could result in mitochondrial disease. It is therefore essential that uniparental transmission of mtDNA is ensured before these techniques are used therapeutically

    Chip and Skim: cloning EMV cards with the pre-play attack

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    EMV, also known as "Chip and PIN", is the leading system for card payments worldwide. It is used throughout Europe and much of Asia, and is starting to be introduced in North America too. Payment cards contain a chip so they can execute an authentication protocol. This protocol requires point-of-sale (POS) terminals or ATMs to generate a nonce, called the unpredictable number, for each transaction to ensure it is fresh. We have discovered that some EMV implementers have merely used counters, timestamps or home-grown algorithms to supply this number. This exposes them to a "pre-play" attack which is indistinguishable from card cloning from the standpoint of the logs available to the card-issuing bank, and can be carried out even if it is impossible to clone a card physically (in the sense of extracting the key material and loading it into another card). Card cloning is the very type of fraud that EMV was supposed to prevent. We describe how we detected the vulnerability, a survey methodology we developed to chart the scope of the weakness, evidence from ATM and terminal experiments in the field, and our implementation of proof-of-concept attacks. We found flaws in widely-used ATMs from the largest manufacturers. We can now explain at least some of the increasing number of frauds in which victims are refused refunds by banks which claim that EMV cards cannot be cloned and that a customer involved in a dispute must therefore be mistaken or complicit. Pre-play attacks may also be carried out by malware in an ATM or POS terminal, or by a man-in-the-middle between the terminal and the acquirer. We explore the design and implementation mistakes that enabled the flaw to evade detection until now: shortcomings of the EMV specification, of the EMV kernel certification process, of implementation testing, formal analysis, or monitoring customer complaints. Finally we discuss countermeasures

    Intra-host evolution of multiple genotypes of hepatitis C virus in a chronically infected patient with HIV along a 13-year follow-up period

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    AbstractThe intra-host evolutionary process of hepatitis C virus (HCV) was analyzed by phylogenetic and coalescent methodologies in a patient co-infected with HCV-1a, HCV-2a, HCV-3a and human immunodeficiency virus (HIV) along a 13-year period.Direct sequence analysis of the E2 and NS5A regions showed diverse evolutionary dynamics, in agreement with different relationships between these regions and the host factors.The Bayesian Skyline Plot analyses of the E2 sequences (cloned) yielded different intra-host evolutionary patterns for each genotype: a steady state of a “consensus” sequence for HCV-1a; a pattern of lineage splitting and extinction for HCV-2a; and a two-phase (drift/diversification) process for HCV-3a.Each genotype evolving in the same patient and at the same time presents a different pattern apparently modulated by the immune pressure of the host.This study provides useful information for the management of co-infected patients and provides insights into the mechanisms behind the intra-host evolution of HCV

    Assisted reproductive technology in the USA: is more regulation needed?

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    The regulation of assisted reproductive technologies is a contested area. Some jurisdictions, such as the UK and a number of Australian states, have comprehensive regulation of most aspects of assisted reproductive technologies; others, such as the USA, have taken a more piecemeal approach and rely on professional guidelines and the general regulation of medical practice to govern this area. It will be argued that such a laissez-faire approach is inadequate for regulating the complex area of assisted reproductive technologies. Two key examples, reducing multiple births and registers of donors and offspring, will be considered to illustrate the effects of the regulatory structure of assisted reproductive technologies in the USA on practice. It will be concluded that the regulatory structure in the USA fails to provide an adequate mechanism for ensuring the ethical and safe conduct of ART services, and that more comprehensive regulation is required

    Genetic Analysis of Axillary Meristem Development in Arabidopsis: Roles of MIR164, CUC1, CUC2, CUC3 and LAS, and identification of novel regulators.

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    Aerial architecture and reproductive success in higher plants is determined by the formation of secondary axes of growth which are formed by axillary meristems initiated post-embryonically in the axils of leaves. Among the genetic modulators of axillary meristem fate in Arabidopsis is LATERAL SUPPRESSOR, a putative transcription factor belonging to the GRAS family, which specifically regulates the initiation of axillary meristems during the vegetative phase of development. The aim of this work was to study the mechanism of LAS function in the meristem and to identify new regulators of axillary meristem initiation in Arabidopsis. To study the spatio-temporal specification of its function, LAS was misexpressed from promoters of meristematic genes possessing adjoining or overlapping expression domains in the SAM. Analysis of STM::LAS, KNAT1::LAS and UFO::LAS transgenic plants in las-4 background revealed partial to complete complementation of the las-4 branching phenotype, but did not lead to the formation of ectopic meristems. These results imply a function for LAS in maintaining the meristematic potential in axillary cells which can later initiate axillary meristems upon activation by other developmental cues. A potential mechanism of LAS function in axillary meristems was investigated by GA spraying experiments and complementation analysis of LAS::GAI and LAS::GAI DELLA transgenic plants in las-4 mutant background. Preliminary results indicate a role for LAS as a regulator of GA signaling in axillary meristems. To identify new regulators of axillary meristem development, two approaches were employed. Firstly, an EMS mutagenesis screen was carried out to identify supperssors of the las-4 max1-1 phenotype. Characterisation of three suppressor of las-4 (sol) candidates, sol2, sol6 and sol7, revealed three novel loci that regulate axillary meristem development. sol2, sol6 and sol7 complemented the branching defect in las-4 max1-1 to different degrees and were found to be non-allelic to each other. Their phenotypes were dependent on the las-4 mutation. Molecular mapping of two of these loci is underway. Secondly, the NAC domain transcription factors CUP-SHAPED COTYLEDON1, CUC2 and CUC3, exhibiting a characteristic expression pattern in the axils of leaf primordia, were investigated for potential roles in the development of axillary meristems. Investigation of loss-of-function mutants of these genes revealed that cuc3-2 is impaired in axillary bud formation, and that the severity of this phenotype is day length dependent. Transcripts of the other two CUC genes, CUC1 and CUC2, are targeted for degradation by miR164. Overexpression of MIR164A or MIR164B in the cuc3-2 mutant caused an almost complete block in axillary bud development. Conversely, plants harbouring miR164-resistant alleles of CUC1 and CUC2 developed accessory buds in rosette and cauline leaf axils, revealing redundant functions of CUC1 and CUC2 in axillary meristem development. Development of accessory buds was also observed in mir164 mutants. Thus, the role of CUC genes and miR164 in regulation of axillary meristem development was unveiled in this study
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