649 research outputs found

    Guidance of a low l/d vehicle entering the earth's atmosphere at speeds up to 50,000 feet per second

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    Guidance of low lift-drag ratio vehicle during earth atmosphere reentr

    The pursuit of happiness: the social and scientific origins of Hans Selye’s natural philosophy of life

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    © The Author(s) 2012. Open access article.In 1956, Hans Selye tentatively suggested that the scientific study of stress could ‘help us to formulate a precise program of conduct’ and ‘teach us the wisdom to live a rich and meaningful life’. Nearly two decades later, Selye expanded this limited vision of social order into a full-blown philosophy of life. In Stress without Distress, first published in 1974, he proposed an ethical code of conduct designed to mitigate personal and social problems. Basing his arguments on contemporary understandings of the biological processes involved in stress reactions, Selye referred to this code as ‘altruistic egotism’. This article explores the origins and evolution of Selye’s ‘natural philosophy of life’, analysing the links between his theories and adjacent intellectual developments in biology, psychosomatic and psychosocial medicine, cybernetics and socio-biology, and situating his work in the broader cultural framework of modern western societies.Wellcome Trus

    Awards, Archives, and Affects: Tropes in the World Press Photo Contest 2009 - 2011

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    __Abstract__ Photography contests have assumed an increasingly significant public role in the context of the global surge of mass-mediated war reporting. This study focuses on the recurrence of visual tropes in press photographs awarded in the annual contest World Press Photo (WPP) in the years 2009–11. By tropes, we mean conventions (e.g. a mourning woman, a civilian facing soldiers, a distressed witness to an atrocity) that remain unchanged despite their travels across the visual sphere, gaining professional and public recognition and having a strong affective impact. We contend that photography contests such as the WPP influence and organize a process of generic understanding of war, disaster and atrocity that is based on a number of persistent tropes, such as the mourner, the protester or the survivor amidst chaos and ruins. We further show that these tropes are gendered along traditional conceptions of femininity and masculinity, appealing strongly to both judges and wider audiences. The evidence for our claim comes from an analysis of the photographs that won awards, observation of the judging sessions, semi-structured interviews with three jury chairmen, and public commentary on the juries’ choices (blogs, newspapers and websites)

    Ergothioneine Biosynthesis and Functionality in the Opportunistic Fungal Pathogen, Aspergillus fumigatus.

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    Ergothioneine (EGT; 2-mercaptohistidine trimethylbetaine) is a trimethylated and sulphurised histidine derivative which exhibits antioxidant properties. Here we report that deletion of Aspergillus fumigatus egtA (AFUA_2G15650), which encodes a trimodular enzyme, abrogated EGT biosynthesis in this opportunistic pathogen. EGT biosynthetic deficiency in A. fumigatus significantly reduced resistance to elevated H2O2 and menadione, respectively, impaired gliotoxin production and resulted in attenuated conidiation. Quantitative proteomic analysis revealed substantial proteomic remodelling in ΔegtA compared to wild-type under both basal and ROS conditions, whereby the abundance of 290 proteins was altered. Specifically, the reciprocal differential abundance of cystathionine γ-synthase and β-lyase, respectively, influenced cystathionine availability to effect EGT biosynthesis. A combined deficiency in EGT biosynthesis and the oxidative stress response regulator Yap1, which led to extreme oxidative stress susceptibility, decreased resistance to heavy metals and production of the extracellular siderophore triacetylfusarinine C and increased accumulation of the intracellular siderophore ferricrocin. EGT dissipated H2O2 in vitro, and elevated intracellular GSH levels accompanied abrogation of EGT biosynthesis. EGT deficiency only decreased resistance to high H2O2 levels which suggests functionality as an auxiliary antioxidant, required for growth at elevated oxidative stress conditions. Combined, these data reveal new interactions between cellular redox homeostasis, secondary metabolism and metal ion homeostasis

    Identification and relative quantification of tyrosine nitration in a model peptide using two-dimensional infrared spectroscopy

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    Nitration of tyrosine in proteins and peptides is a post-translational modification that occurs under conditions of oxidative stress. It is implicated in a variety of medical conditions, including neurodegenerative and cardiovascular diseases. However, monitoring tyrosine nitration and understanding its role in modifying biological function remains a major challenge. In this work, we investigate the use of electron-vibration-vibration (EVV) two-dimensional infrared (2DIR) spectroscopy for the study of tyrosine nitration in model peptides. We demonstrate the ability of EVV 2DIR spectroscopy to differentiate between the neutral and deprotonated states of 3-nitrotyrosine, and we characterize their spectral signatures using information obtained from quantum chemistry calculations and simulated EVV 2DIR spectra. To test the sensitivity of the technique, we use mixed-peptide samples containing various levels of tyrosine nitration, and we use mass spectrometry to independently verify the level of nitration. We conclude that EVV 2DIR spectroscopy is able to provide detailed spectroscopic information on peptide side-chain modifications and to detect nitration levels down to 1%. We further propose that lower nitration levels could be detected by introducing a resonant Raman probe step to increase the detection sensitivity of EVV 2DIR spectroscopy. (Graph Presented)
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