618 research outputs found

    RECOVERY OF TURGOR BY CUT SHOOTS AFTER WILTING

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    Fungal Origins of the Bicyclo[2.2.2]diazaoctane Ring System of Prenylated Indole Alkaloids

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    Over eight different families of natural products, consisting of nearly seventy secondary metabolites, which contain the bicyclo[2.2.2]diazaoctane ring system, have been isolated from various Aspergillus, Penicillium, and Malbranchea species. Since 1968, these secondary metabolites have been the focus of numerous biogenetic, synthetic, taxonomic, and biological studies, and, as such, have made a lasting impact across multiple scientific disciplines. This review covers the isolation, biosynthesis, and biological activity of these unique secondary metabolites containing the bridging bicyclo[2.2.2]diazaoctane ring system. Furthermore, the diverse fungal origin of these natural products is closely examined and, in many cases, updated to reflect the currently accepted fungal taxonomy

    Sonic boom and drag evaluation of supersonic jet concepts

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    This paper evaluates three different class supersonic airliners (Concorde, Cranfield E-5, and NASA QueSST X-plane) in a multidisciplinary design analysis optimization (MDAO) environment in terms of their sonic boom intensities and aerodynamic performance. The aerodynamic analysis and sonic boom prediction methods are key to this research. The panel method PANAIR is integrated to perform automated aerodynamic analysis. The drag coefficient is corrected by the Harris wave drag formula and form factor method. For sonic boom prediction, the near-field pressure is predicted through the Whitham F-function method. The F-function is decomposed to the F-function due to volume and the F-function due to lift to see their individual effect on sonic boom. The near-field signature propagates in a stratified windy atmosphere using the waveform parameter method. The aerodynamic results are compared with experimental data and the sonic boom prediction results are validated by the NASA PCBoom program. Through the evaluation, we find a direct link between the wave drag and the first derivative of the volume distribution. The sonic boom intensity is influenced by the lift distribution and the volume change rate. The study helps to study the feasibility of low-boom and low-drag supersonic airliners

    How Biology Became Social and What It Means for Social Theory

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    In this paper I first offer a systematic outline of a series of conceptual novelties in the life-sciences that have favoured, over the last three decades, the emergence of a more social view of biology. I focus in particular on three areas of investigation: (1) technical changes in evolutionary literature that have provoked a rethinking of the possibility of altruism, morality and prosocial behaviours in evolution; (2) changes in neuroscience, from an understanding of the brain as an isolated data processor to the ultrasocial and multiply connected social brain of contemporary neuroscience; and (3) changes in molecular biology, from the view of the gene as an autonomous master of development to the ‘reactive genome’ of the new emerging field of molecular epigenetics. In the second section I reflect on the possible implications for the social sciences of this novel biosocial terrain and argue that the postgenomic language of extended epigenetic inheritance and blurring of the nature/nurture boundaries will be as provocative for neo-Darwinism as it is for the social sciences as we have known them. Signs of a new biosocial language are emerging in several social-science disciplines and this may represent an exciting theoretical novelty for twenty-first social theory

    Collaboration and knowledge exchange between scholars in Britain and the empire, 1830–1914

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    In recent years there has been a growing interest among historians in the British Empire as a space of knowledge production and circulation. Much of this work assumes that scholarly cooperation and collaboration between individuals and institutions within the Empire had the effect (and often also the aim) of strengthening both imperial ties and the idea of empire. This chapter argues, however, that many examples of scholarly travel, exchange, and collaboration were undertaken with very different goals in mind. In particular, it highlights the continuing importance of an ideal of scientific internationalism, which stressed the benefits of scholarship for the whole of humanity and prioritized the needs and goals of individual academic and scientific disciplines. As the chapter shows, some scholars even went on to develop nuanced critiques of the imperial project while using the very structures of empire to further their own individual, disciplinary and institutional goals

    Murine Gammaretrovirus Group G3 Was Not Found in Swedish Patients with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome and Fibromyalgia

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    BACKGROUND: The recent report of gammaretroviruses of probable murine origin in humans, called xenotropic murine retrovirus related virus (XMRV) and human murine leukemia virus related virus (HMRV), necessitated a bioinformatic search for this virus in genomes of the mouse and other vertebrates, and by PCR in humans. RESULTS: Three major groups of murine endogenous gammaretroviruses were identified. The third group encompassed both exogenous and endogenous Murine Leukemia Viruses (MLVs), and most XMRV/HMRV sequences reported from patients suffering from myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). Two sensitive real-time PCRs for this group were developed. The predicted and observed amplification range for these and three published XMRV/HMRV PCRs demonstrated conspicuous differences between some of them, partly explainable by a recombinatorial origin of XMRV. Three reverse transcription real-time PCRs (RTQPCRs), directed against conserved and not overlapping stretches of env, gag and integrase (INT) sequences of XMRV/HMRV were used on human samples. White blood cells from 78 patients suffering from ME/CFS, of which 30 patients also fulfilled the diagnostic criteria for fibromyalgia (ME/CFS/FM) and in 7 patients with fibromyalgia (FM) only, all from the Gothenburg area of Sweden. As controls we analyzed 168 sera from Uppsala blood donors. We controlled for presence and amplifiability of nucleic acid and for mouse DNA contamination. To score as positive, a sample had to react with several of the XMRV/HMRV PCRs. None of the samples gave PCR reactions which fulfilled the positivity criteria. CONCLUSIONS: XMRV/HMRV like proviruses occur in the third murine gammaretrovirus group, characterized here. PCRs developed by us, and others, approximately cover this group, except for the INT RTQPCR, which is rather strictly XMRV specific. Using such PCRs, XMRV/HMRV could not be detected in PBMC and plasma samples from Swedish patients suffering from ME/CFS/FM, and in sera from Swedish blood donors
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