478 research outputs found

    OsSFR6 is a functional rice orthologue of SENSITIVE TO FREEZING-6 and can act as a regulator of COR gene expression, osmotic stress and freezing tolerance in Arabidopsis

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    The Arabidopsis protein SENSITIVE TO FREEZING-6 (AtSFR6) is required for cold- and drought-inducible expression of COLD-ON REGULATED (COR) genes and, as a consequence, AtSFR6 is essential for osmotic stress and freezing tolerance in Arabidopsis. Therefore, orthologues of AtSFR6 in crop species represent important candidate targets for future manipulation of stress tolerance. We identified and cloned a homologue of AtSFR6 from rice (Oryza sativa), OsSFR6, and confirmed its orthology in Arabidopsis. OsSFR6 was identified by homology searches, and a full-length coding region isolated using reverse transcription polymerase chain reaction (RT-PCR) from Oryza sativa cDNA. To test for orthology, OsSFR6 was expressed in an Arabidopsis sfr6 loss-of-function mutant background, and restoration of wild-type phenotypes was assessed. Searching the rice genome revealed a single homologue of AtSFR6. Cloning and sequencing the OsSFR6 coding region showed OsSFR6 to have 61.7% identity and 71.1% similarity to AtSFR6 at the predicted protein sequence level. Expression of OsSFR6 in the atsfr6 mutant background restored the wild-type visible phenotype, as well as restoring wild-type levels of COR gene expression and tolerance of osmotic and freezing stresses. OsSFR6 is an orthologue of AtSFR6, and thus a target for future manipulation to improve tolerance to osmotic and other abiotic stresses

    The Arabidopsis Mediator complex subunits MED16, MED14 and MED2 regulate Mediator and RNA polymerase II recruitment to CBF-responsive cold-regulated genes

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    The Mediator16 (MED16; formerly termed SENSITIVE TO FREEZING6 [SFR6]) subunit of the plant Mediator transcriptional coactivator complex regulates cold-responsive gene expression in Arabidopsis thaliana, acting downstream of the C-repeat binding factor (CBF) transcription factors to recruit the core Mediator complex to cold-regulated genes. Here, we use loss-of-function mutants to show that RNA polymerase II recruitment to CBF-responsive cold-regulated genes requires MED16, MED2, and MED14 subunits. Transcription of genes known to be regulated via CBFs binding to the C-repeat motif/drought-responsive element promoter motif requires all three Mediator subunits, as does cold acclimation–induced freezing tolerance. In addition, these three subunits are required for low temperature–induced expression of some other, but not all, cold-responsive genes, including genes that are not known targets of CBFs. Genes inducible by darkness also required MED16 but required a different combination of Mediator subunits for their expression than the genes induced by cold. Together, our data illustrate that plants control transcription of specific genes through the action of subsets of Mediator subunits; the specific combination defined by the nature of the stimulus but also by the identity of the gene induced

    Stability of Asn_n [n=4, 8, 20, 28, 32, 36, 60] Cage Structures

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    We present all-electron density functional study of the geometry, electronic structure, vibrational modes, polarizabilities as well as the infrared and Raman spectra of fullerene-like arsenic cages. The stability of Asn_n cages for sizes 4, 8, 20, 28, 32, 36, and 60 wherein each As atom is three-fold coordinated is examined. We find that all the cages studied are vibrationally stable and while all the clusters are energetically stable with respect to isolated arsenic atoms, only As20_{20} is energetically stable against dissociation into As4_4. We suggest that the Raman spectra might be a means for observing the As20_{20} molecule in gas phase.Comment: Uses elsart.cls (Elsevier Science), (Better pictures can be obtained from authors); Manuscript to appear in Chemical Physics Letter

    Genetic partitioning of interleukin-6 signalling in mice dissociates Stat3 from Smad3-mediated lung fibrosis

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    Idiopathic pulmonary fibrosis (IPF) is a fatal disease that is unresponsive to current therapies and characterized by excessive collagen deposition and subsequent fibrosis. While inflammatory cytokines, including interleukin (IL)-6, are elevated in IPF, the molecular mechanisms that underlie this disease are incompletely understood, although the development of fibrosis is believed to depend on canonical transforming growth factor (TGF)-ÎČ signalling. We examined bleomycin-induced inflammation and fibrosis in mice carrying a mutation in the shared IL-6 family receptor gp130. Using genetic complementation, we directly correlate the extent of IL-6-mediated, excessive Stat3 activity with inflammatory infiltrates in the lung and the severity of fibrosis in corresponding gp130757F mice. The extent of fibrosis was attenuated in B lymphocyte-deficient gp130757F;”MT−/− compound mutant mice, but fibrosis still occurred in their Smad3−/− counterparts consistent with the capacity of excessive Stat3 activity to induce collagen 1α1 gene transcription independently of canonical TGF-ÎČ/Smad3 signalling. These findings are of therapeutic relevance, since we confirmed abundant STAT3 activation in fibrotic lungs from IPF patients and showed that genetic reduction of Stat3 protected mice from bleomycin-induced lung fibrosis

    Rebirth of X-ray Emission from the Born-Again Planetary Nebula A 30

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    The planetary nebula (PN) A30 is believed to have undergone a very late thermal pulse resulting in the ejection of knots of hydrogen-poor material. Using HST images we have detected the angular expansion of these knots and derived an age of 850+280-150 yr. To investigate the spectral and spatial properties of the soft X-ray emission detected by ROSAT, we have obtained Chandra and XMM-Newton observations of A30. The X-ray emission from A30 can be separated into two components: a point-source at the central star and diffuse emission associated with the hydrogen-poor knots and the cloverleaf structure inside the nebular shell. To help us assess the role of the current stellar wind in powering this X-ray emission, we have determined the stellar parameters of the central star of A 30 using a non-LTE model fit to its optical and UV spectrum. The spatial distribution and spectral properties of the diffuse X-ray emission is suggestive that it is generated by the post-born-again and present fast stellar winds interacting with the hydrogen-poor ejecta of the born-again event. This emission can be attributed to shock-heated plasma, as the hydrogen-poor knots are ablated by the stellar winds, under which circumstances the efficient mass-loading of the present fast stellar wind raises its density and damps its velocity to produce the observed diffuse soft X-rays. Charge transfer reactions between the ions of the stellar winds and material of the born-again ejecta has also been considered as a possible mechanism for the production of diffuse X-ray emission, and upper limits on the expected X-ray production by this mechanism have been derived. The origin of the X-ray emission from the central star of A 30 is puzzling: shocks in the present fast stellar wind and photospheric emission can be ruled out, while the development of a new, compact hot bubble confining the fast stellar wind seems implausible.Comment: 29 pages, 11 figures, 4 tables; accepted for publication by Ap

    The analysis of facial beauty: an emerging area of research in pattern analysis

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    Much research presented recently supports the idea that the human perception of attractiveness is data-driven and largely irrespective of the perceiver. This suggests using pattern analysis techniques for beauty analysis. Several scientific papers on this subject are appearing in image processing, computer vision and pattern analysis contexts, or use techniques of these areas. In this paper, we will survey the recent studies on automatic analysis of facial beauty, and discuss research lines and practical application

    Risks, alternative knowledge strategies and democratic legitimacy: the conflict over co-incineration of hazardous industrial waste in Portugal.

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    The decision to incinerate hazardous industrial waste in cement plants (the socalled ‘co-incineration’ process) gave rise to one of the most heated environmental conflicts ever to take place in Portugal. The bitterest period was between 1997 and 2002, after the government had made a decision. Strong protests by residents, environmental organizations, opposition parties, and some members of the scientific community forced the government to backtrack and to seek scientific legitimacy for the process through scientific expertise. The experts ratified the government’s decision, stating that the risks involved were socially acceptable. The conflict persisted over a decade and ended up clearing the way for a more sustainable method over which there was broad social consensus – a multifunctional method which makes it possible to treat, recover and regenerate most wastes. Focusing the analysis on this conflict, this paper has three aims: (1) to discuss the implications of the fact that expertise was ‘confiscated’ after the government had committed itself to the decision to implement co-incineration and by way of a reaction to the atmosphere of tension and protest; (2) to analyse the uses of the notions of ‘risk’ and ‘uncertainty’ in scientific reports from both experts and counter-experts’ committees, and their different assumptions about controllability and criteria for considering certain practices to be sufficiently safe for the public; and (3) to show how the existence of different technical scientific and political attitudes (one more closely tied to government and the corporate interests of the cement plants, the other closer to the environmental values of reuse and recycling and respect for the risk perception of residents who challenged the facilities) is closely bound up with problems of democratic legitimacy. This conflict showed how adopting more sustainable and lower-risk policies implies a broader view of democratic legitimacy, one which involves both civic movements and citizens themselves

    The Science of Sungrazers, Sunskirters, and Other Near-Sun Comets

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    This review addresses our current understanding of comets that venture close to the Sun, and are hence exposed to much more extreme conditions than comets that are typically studied from Earth. The extreme solar heating and plasma environments that these objects encounter change many aspects of their behaviour, thus yielding valuable information on both the comets themselves that complements other data we have on primitive solar system bodies, as well as on the near-solar environment which they traverse. We propose clear definitions for these comets: We use the term near-Sun comets to encompass all objects that pass sunward of the perihelion distance of planet Mercury (0.307 AU). Sunskirters are defined as objects that pass within 33 solar radii of the Sun’s centre, equal to half of Mercury’s perihelion distance, and the commonly-used phrase sungrazers to be objects that reach perihelion within 3.45 solar radii, i.e. the fluid Roche limit. Finally, comets with orbits that intersect the solar photosphere are termed sundivers. We summarize past studies of these objects, as well as the instruments and facilities used to study them, including space-based platforms that have led to a recent revolution in the quantity and quality of relevant observations. Relevant comet populations are described, including the Kreutz, Marsden, Kracht, and Meyer groups, near-Sun asteroids, and a brief discussion of their origins. The importance of light curves and the clues they provide on cometary composition are emphasized, together with what information has been gleaned about nucleus parameters, including the sizes and masses of objects and their families, and their tensile strengths. The physical processes occurring at these objects are considered in some detail, including the disruption of nuclei, sublimation, and ionisation, and we consider the mass, momentum, and energy loss of comets in the corona and those that venture to lower altitudes. The different components of comae and tails are described, including dust, neutral and ionised gases, their chemical reactions, and their contributions to the near-Sun environment. Comet-solar wind interactions are discussed, including the use of comets as probes of solar wind and coronal conditions in their vicinities. We address the relevance of work on comets near the Sun to similar objects orbiting other stars, and conclude with a discussion of future directions for the field and the planned ground- and space-based facilities that will allow us to address those science topics

    Targeting Potential Drivers of COVID-19: Neutrophil Extracellular Traps

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    Coronavirus disease 2019 (COVID-19) is a novel, viral-induced respiratory disease that in ∌10-15% of patients progresses to acute respiratory distress syndrome (ARDS) triggered by a cytokine storm. In this Perspective, autopsy results and literature are presented supporting the hypothesis that a little known yet powerful function of neutrophils-the ability to form neutrophil extracellular traps (NETs)-may contribute to organ damage and mortality in COVID-19. We show lung infiltration of neutrophils in an autopsy specimen from a patient who succumbed to COVID-19. We discuss prior reports linking aberrant NET formation to pulmonary diseases, thrombosis, mucous secretions in the airways, and cytokine production. If our hypothesis is correct, targeting NETs directly and/or indirectly with existing drugs may reduce the clinical severity of COVID-19

    Wikipedia as informal self-education for clinical decision-making in medical practice

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    Background For almost any topic, a Wikipedia page will appear among the first ten items of a search online. Wikipedia is also a site whose quality and reliability has been called into question. Methods In this paper, we aim to discuss medical practitioners’ use of Wikipedia, what this consists of and what it might be. We consider the context and history of Wikipedia before discussing the relationship between Wikipedia and the medical profession. In so doing, we will consider Wikipedia as a means of informal self-education and the extent to which it might inform clinical decision-making. We compare with the existing literature results from our two small-scale empirical studies of Wikipedia and clinical decision-making. Results Notwithstanding issues over quality and reliability, Wikipedia’s rules on verifiability are such that its articles are very heavily referenced, and this is just as true of health-related articles. The Cochrane/Wikipedia Initiative in improving the quality and reliability of medical and health pages in Wikipedia is significant in increasing reliability. Our respondents largely concurred with the results from earlier studies on the use of Wikipedia by medical practitioners. Conclusion Perhaps the very doubt over Wikipedia’s accuracy is its greatest strength as a means of informal education of doctors. That medical and health articles on Wikipedia can be so fully referenced and still be doubted is arguably a good thing and one whose effects may be spread into other, more trusted, publications. Hence, one might envisage a future where no one source is taken automatically on trust. Keywords Wikipedia, informal education, continued professional development, medical education
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