260 research outputs found

    Vaccum Gas Tungsten Arc Welding, phase 1

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    This two year program will investigate Vacuum Gas Tungsten Arc Welding (VGTAW) as a method to modify or improve the weldability of normally difficult-to-weld materials. VGTAW appears to offer a significant improvement in weldability because of the clean environment and lower heat input needed. The overall objective of the program is to develop the VGTAW technology and implement it into a manufacturing environment that will result in lower cost, better quality and higher reliability aerospace components for the space shuttle and other NASA space systems. Phase 1 of this program was aimed at demonstrating the process's ability to weld normally difficult-to-weld materials. Phase 2 will focus on further evaluation, a hardware demonstration and a plan to implement VGTAW technology into a manufacturing environment. During Phase 1, the following tasks were performed: (1) Task 11000 Facility Modification - an existing vacuum chamber was modified and adapted to a GTAW power supply; (2) Task 12000 Materials Selection - four difficult-to-weld materials typically used in the construction of aerospace hardware were chosen for study; (3) Task 13000 VGTAW Experiments - welding experiments were conducted under vacuum using the hollow tungsten electrode and evaluation. As a result of this effort, two materials, NARloy Z and Incoloy 903, were downselected for further characterization in Phase 2; and (4) Task 13100 Aluminum-Lithium Weld Studies - this task was added to the original work statement to investigate the effects of vacuum welding and weld pool vibration on aluminum-lithium alloys

    Octopus-inspired adhesive skins for intelligent and rapidly switchable underwater adhesion

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    The octopus couples controllable adhesives with intricately embedded sensing, processing, and control to manipulate underwater objects. Current synthetic adhesive–based manipulators are typically manually operated without sensing or control and can be slow to activate and release adhesion, which limits system-level manipulation. Here, we couple switchable, octopus-inspired adhesives with embedded sensing, processing, and control for robust underwater manipulation. Adhesion strength is switched over 450× from the ON to OFF state in \u3c50 ms over many cycles with an actively controlled membrane. Systematic design of adhesive geometry enables adherence to nonideal surfaces with low preload and independent control of adhesive strength and adhesive toughness for strong and reliable attachment and easy release. Our bio-inspired nervous system detects objects and autonomously triggers the switchable adhesives. This is implemented into a wearable glove where an array of adhesives and sensors creates a biomimetic adhesive skin to manipulate diverse underwater objects

    Perceptions of institutional complexity and lobbyists’ decisions to join lobbying coalitions – evidence from the European Union context

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    YesWe use data from in-depth interviews with business lobbyists in Brussels to investigate why they choose to join lobbying coalitions. We find that lobbyists face two competing institutional incentives. First, they are confronted with incentives to ally with other European organisations, develop multilateral policy messages, and communicate messages to the Commission and the Parliament. Simultaneously, they face inducements to join narrower coalitions, develop bilateral policy messages, and direct those messages at the Council. Lobbyists’ receptivity to these incentives – and thus their choices of lobbying coalitions – differs with their age, educational background, and with the type and ownership structure of the organisations they represent. Combined, our findings contribute to the limited, mainly American literature on interest coalitions by demonstrating that lobbyists operate in complex institutional environments, and that their interpretations of and reactions to institutional complexity are shaped by individual- and organisational-level factors

    Cultural and Media Identity Among Latvian Migrants in Germany

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    This chapter explores how transnational media and culture impacts on the identity formation of recent Latvian migrants in Germany. In the context of the EU, Germany opened its labour market to the new EU countries rather late, when compared to other ‘old’ EU countries. This has had an effect on the composition of the group of Latvian migrants going to Germany, and their identities. In the light of this, this chapter examines how Latvian migrants in Germany feel and experience their belonging to Latvia and its culture. It analyses the social and communicative practices crucial for the development of belonging, including the rootedness in the country where they live and the cultural references that are important for them. The evidence for the analysis in this chapter comes from in-depth interviews, open media diaries and network maps of Latvian migrants in Germany. The chapter situates the description of evidence in the framework of cultural identity concepts and discusses the role of culture and media in the process of building migrant identity. The chapter argues that culture is shaping the transnational self-perception of Latvian migrants in Germany – as it provides collective narratives of imagined common frames of references, and confirms feelings of belonging and distinction

    Endothelial nitric oxide synthase gene polymorphism (Glu298Asp) and development of pre-eclampsia: a case-control study and a meta-analysis

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    BACKGROUND: Pre-eclampsia is thought to have an important genetic component. Recently, pre-eclampsia has been associated in some studies with carriage of a common eNOS gene Glu298Asp polymorphism, a variant that leads to the replacement of glutamic acid by aspartic acid at codon 298. METHOD: Healthy women with singleton pregnancies were recruited from 7 district general hospitals in London, UK. Women at high risk of pre-eclampsia were screened by uterine artery Doppler velocimetry at 22–24 weeks of gestation and maternal blood was obtained to genotype the eNOS Glu298Asp polymorphism. Odds ratios (OR) and 95%CI, using logistic regression methods, were obtained to evaluate the association between the Glu298Asp polymorphism and pre-eclampsia. A meta-analysis was then undertaken of all published studies up to November 2005 examining the association of eNOS Glu298Asp genotype and pre-eclampsia. RESULTS: 89 women with pre-eclampsia and 349 controls were included in the new study. The Glu298Asp polymorphism in a recessive model was not significantly associated with pre-eclampsia (adjusted-OR: 0.83 [95%CI: 0.30–2.25]; p = 0.7). In the meta-analysis, under a recessive genetic model (1129 cases & 2384 controls) women homozygous for the Asp298 allele were not at significantly increased risk of pre-eclampsia (OR: 1.28 [95%CI: 0.76–2.16]; p = 0.34). A dominant model (1334 cases & 2894 controls) was associated with no increase of risk of pre-eclampsia for women carriers of the Asp298 allele (OR: 1.12 [95%CI: 0.84–1.49]; p = 0.42). CONCLUSION: From the data currently available, the eNOS Glu298Asp polymorphism is not associated with a significant increased risk of pre-eclampsia. However, published studies have been underpowered, much larger studies are needed to confirm or refute a realistic genotypic risk of disease, but which might contribute to many cases of pre-eclampsia in the population

    Promotion of prostatic metastatic migration towards human bone marrow stoma by Omega 6 and its inhibition by Omega 3 PUFAs

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    Epidemiological studies have shown not only a relationship between the intake of dietary lipids and an increased risk of developing metastatic prostate cancer, but also the type of lipid intake that influences the risk of metastatic prostate cancer. The Omega-6 poly-unsaturated fatty acid, Arachidonic acid, has been shown to enhance the proliferation of malignant prostate epithelial cells and increase the risk of advanced prostate cancer. However, its role in potentiating the migration of cancer cells is unknown. Here we show that arachidonic acid at concentrations ⩽5 μM is a potent stimulator of malignant epithelial cellular invasion, which is able to restore invasion toward hydrocortisone-deprived adipocyte-free human bone marrow stroma completely. This observed invasion is mediated by the arachidonic acid metabolite prostaglandin E2 and is inhibited by the Omega-3 poly-unsaturated fatty acids eicosapentaenoic acid and docosahexaenoic acid at a ratio of 1 : 2 Omega-3 : Omega-6, and by the COX-2 inhibitor NS-398. These results identify a mechanism by which arachidonic acid may potentiate the risk of metastatic migration and secondary implantation in vivo, a risk which can be reduced with the uptake of Omega-3 poly-unsaturated fatty acids

    Between mediatisation and politicisation: The changing role and position of Whitehall press officers in the age of political spin

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    Despite widespread critiques of ‘political spin’, the way governments engage with the mass media has attracted relatively little empirical attention. There is a small but growing body of research into bureaucracies’ responses to mediatisation from within which have identified tensions between bureaucratic and party political values, but this has not included the United Kingdom. There are concerns that the traditional dividing line between government information and political propaganda has come under increasing pressure as a higher premium is placed on persuasion by both journalists and politicians battling for public attention in an increasingly competitive market. Within Whitehall, the arrival of Labour in 1997 after 18 years in opposition was a watershed for UK government communications, allowing the government to reconfigure its official information service in line with the party political imperative to deploy strategic communications as a defence against increasingly invasive media scrutiny. Public relations, in government as elsewhere, has grown in scale, scope and status, becoming institutionalised and normalised within state bureaucracies, but how has this affected the role, status and influence of the civil servants who conduct media management? Within the system of executive self-regulation of government publicity that is characteristic of Whitehall, government press officers must negotiate a difficult path between the need to inform citizens about the government’s programme, and demands by ministers to deploy privileged information to secure and maintain personal and party advantage in the struggle for power. Taking 1997 as a turning point, and through the voices of the actors who negotiate government news – mainly press officers, but also journalists and special advisers – this article examines the changing role and position of Whitehall press officers in what has become known as the age of political spin, finding that profound and lasting change in the rules of engagement has taken place and is continuing

    Variation in the human soluble epoxide hydrolase gene and risk of restenosis after percutaneous coronary intervention

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    <p>Abstract</p> <p>Background</p> <p>Restenosis represents the major limiting factor for the long-term efficacy of percutaneous coronary intervention (PCI). Several genetic factors involved in the regulation of the vascular system have been described to play a role in the pathogenesis of restenosis. We investigated whether the <it>EPHX2 K55R </it>polymorphism, previously linked to significantly higher risk for coronary heart disease (CHD), was associated with the occurrence of restenosis after PCI. The association with incident CHD should have been confirmed and a potential correlation of the <it>EPHX2 K55R </it>variant to an increased risk of hypertension was analysed.</p> <p>Methods</p> <p>An overall cohort of 706 patients was studied: This cohort comprised of 435 CHD patients who had undergone successful PCI. Follow-up coronary angiography in all patients was performed 6 months after intervention. Another 271 patients in whom CHD had been excluded by coronary angiography served as controls. From each patient EDTA-blood was drawn at the baseline ward round. Genomic DNA was extracted from these samples and genotyping was performed by real-time PCR and subsequent melting curve analysis.</p> <p>Results</p> <p>In CHD patients 6 month follow-up coronary angiography revealed a restenosis rate of 29.4%, classified as late lumen loss as well as lumen re-narrowing ≥ 50%.</p> <p>Statistical analysis showed an equal genotype distribution in restenosis patients and non-restenosis patients (A/A 82.0% and A/G + G/G 18.0% versus A/A 82.1% and A/G + G/G 17.9%). Moreover, neither a significant difference in the genotype distribution of CHD patients and controls nor an association with increased risk of hypertension was found.</p> <p>Conclusion</p> <p>The results of the present study indicate that the <it>EPHX2 K55R </it>polymorphism is not associated with restenosis after PCI, with incidence of CHD, or with an increased risk of hypertension and therefore, can not serve as a predictor for risk of CHD or restenosis after PCI.</p

    Sex Machines as Mediatized Sexualities -Ethical and Social Implications

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    Sex machines are also communication practices. This chapter considers sexual interactions with technological devices as mediatized sexualities. Media are integrated in the definition of most of the contexts of human life—and the combination of the mediatization perspective with an Actor-Network Theory enables an organic cross-disciplinary discussion about technologies across specific socio-cultural fields. Sex machines, hybrids of fundamental humanness and either or both artificiality and artifactuality, push the boundaries and raise social and ethical discussions about the limits of the integrated circuit involving society, individuals, culture, values, interactivity and intercourse. Therefore, a consideration of sex machines enriches media discussions on technologies, communicative, social and cultural practices and ethical debates. This chapter starts with a discussion on how sex machines belong to the world of mediatized sexualities. After an introductory section on mediatization, ethics and sex machines, the argument builds on a typology of sex machines (similarity, extension, substitution, sublimation, sensuality and creativity) to provide a discussion on ethical issues. The debates consider, amongst others, robots, surveillance, psychological, sociological and body-related concerns, which are also relevant for media and communication studies

    E-NTPDases in human airways: Regulation and relevance for chronic lung diseases

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    Chronic obstructive lung diseases are characterized by the inability to prevent bacterial infection and a gradual loss of lung function caused by recurrent inflammatory responses. In the past decade, numerous studies have demonstrated the importance of nucleotide-mediated bacterial clearance. Their interaction with P2 receptors on airway epithelia provides a rapid ‘on-and-off’ signal stimulating mucus secretion, cilia beating activity and surface hydration. On the other hand, abnormally high ATP levels resulting from damaged epithelia and bacterial lysis may cause lung edema and exacerbate inflammatory responses. Airway ATP concentrations are regulated by ecto nucleoside triphosphate diphosphohydrolases (E-NTPDases) which are expressed on the mucosal surface and catalyze the sequential dephosphorylation of nucleoside triphosphates to nucleoside monophosphates (ATP → ADP → AMP). The common bacterial product, Pseudomonas aeruginosa lipopolysaccharide (LPS), induces an acute reduction in azide-sensitive E-NTPDase activities, followed by a sustained increase in activity as well as NTPDase 1 and NTPDase 3 expression. Accordingly, chronic lung diseases, including cystic fibrosis (CF) and primary ciliary dyskinesia, are characterized by higher rates of nucleotide elimination, azide-sensitive E-NTPDase activities and expression. This review integrates the biphasic regulation of airway E-NTPDases with the function of purine signaling in lung diseases. During acute insults, a transient reduction in E-NTPDase activities may be beneficial to stimulate ATP-mediated bacterial clearance. In chronic lung diseases, elevating E-NTPDase activities may represent an attempt to prevent P2 receptor desensitization and nucleotide-mediated lung damage
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