135 research outputs found

    The Ball in the Hole

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    “The Ball in The Hole” is an interactive video installation, running on GPL homemade software, which uses the principle of tele-presence. Two rooms are showing a projected mirror, where the user can see and recognise himself. On the floor there is a spiral, containing a luminescent ball. When the user grabs the ball, spontaneously attempting to play with it, the projected mirror will start erasing, showing the other room. The ball, as an interface, will act on the video as an eraser on a pencil drawing. The two rooms / spaces are symmetrical. After the complete erasure of the image, the mirror will show the remote room only. At this point the game flips: the ball, rubber and pencil at the same time, gets the capability to erase the other person / space / video. Therefore this deletion of the Otherness corresponds to the redrawing of the Self. You draw as much as you erase, in direct proportion. The process continues endlessly rendering the installation a social happening where the user becomes the main character of an improvised performance

    K -> pi vector form factor with N_f=2+1+1 Twisted Mass fermions

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    We present a lattice QCD determination of the vector form factor of the kaon semileptonic decay K -> pi l nu which is relevant for the extraction of the CKM matrix element |V_{us}| from experimental data. Our result is based on the gauge configurations produced by the European Twisted Mass Collaboration with N_f=2+1+1 dynamical fermions. We simulated at three different values of the lattice spacing and with pion masses as small as 210 MeV. Our preliminary estimate for the vector form factor at zero momentum transfer is f_+(0)=0.9683(65), where the uncertainty is both statistical and systematic. By combining our result with the experimental value of f_+(0)|V_{us}| we obtain |V_{us}|=0.2234(16), which satisfies the unitarity constraint of the Standard Model at the permille level

    Biochemical mechanism of phosphorus limitation impairing nitrogen fixation in diazotrophic bacterium <i>Klebsiella variicola</i> W12

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    Introduction: Biological nitrogen (N) fixation (BNF) plays a key role in nitrogen supply in agricultural and natural ecosystems. Harnessing BNF can substantially reduce dependence on chemical fertilizer in agroecosystems and hence can contribute to sustainable agriculture. However, a number of field studies have demonstrated that BNF can be largely suppressed in phosphorus (P)-deficient environments, while the underlying mechanism is not well understood.Materials &amp; Methods: In this study, comparative proteomics and lipidomics analyses were conducted on a diazotrophic bacterium Klebsiella variicola W12 under P-deficient and P-replete conditions to gain insight into how P availability affects N fixation.Results: Under P deficiency, N fixation activity of K. variicola W12 was severely repressed. In response to P limitation, the bacterium synthesized P-free ornithine lipids to replace glycerophospholipids in its membrane to reduce cellular demand for P. Comparative proteomics showed that P limitation resulted in upregulation of the PhoBR two-component system, a range of organic and inorganic P uptake and transport systems, while nitrogenase and N-fixation-related transcriptional regulators NifL and NifA were downregulated.Conclusion: These results revealed lipid renovation as an adaptation strategy for N2-fixing microbes to survive under P stress and provided biochemical evidence on how P availability regulates BNF. A conceptual model of N–P coupling at the microbial metabolism level is therefore proposed. Our study provides a simple yet plausible explanation of how P deficiency suppresses BNF observed in the field and highlights the importance of regulating P availability to maximize the potential of BNF in agroecosystems for agriculture sustainable production

    Biochemical mechanism of phosphorus limitation impairing nitrogen fixation in diazotrophic bacterium <i>Klebsiella variicola</i> W12

    Get PDF
    Introduction: Biological nitrogen (N) fixation (BNF) plays a key role in nitrogen supply in agricultural and natural ecosystems. Harnessing BNF can substantially reduce dependence on chemical fertilizer in agroecosystems and hence can contribute to sustainable agriculture. However, a number of field studies have demonstrated that BNF can be largely suppressed in phosphorus (P)-deficient environments, while the underlying mechanism is not well understood.Materials &amp; Methods: In this study, comparative proteomics and lipidomics analyses were conducted on a diazotrophic bacterium Klebsiella variicola W12 under P-deficient and P-replete conditions to gain insight into how P availability affects N fixation.Results: Under P deficiency, N fixation activity of K. variicola W12 was severely repressed. In response to P limitation, the bacterium synthesized P-free ornithine lipids to replace glycerophospholipids in its membrane to reduce cellular demand for P. Comparative proteomics showed that P limitation resulted in upregulation of the PhoBR two-component system, a range of organic and inorganic P uptake and transport systems, while nitrogenase and N-fixation-related transcriptional regulators NifL and NifA were downregulated.Conclusion: These results revealed lipid renovation as an adaptation strategy for N2-fixing microbes to survive under P stress and provided biochemical evidence on how P availability regulates BNF. A conceptual model of N–P coupling at the microbial metabolism level is therefore proposed. Our study provides a simple yet plausible explanation of how P deficiency suppresses BNF observed in the field and highlights the importance of regulating P availability to maximize the potential of BNF in agroecosystems for agriculture sustainable production

    Per il nuovo Archiloco (P. Col. 7511)

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    Presentation, of a series of conjectures and new proposals on the recently published “New Archilochus” (P.Col, inv. 7511 [196a West2]) with remarks on lines 1, 5, 9, 19, 28 f., 33

    Central Precocious Puberty: Treatment with Triptorelin 11.25 mg

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    Background. Few data are available on quarterly 11.25 mg GnRH analog treatment in central precocious puberty (CPP). Aim. To assess the efficacy of triptorelin 11.25 mg in children with CPP. Patients. 17 patients (16 females) with CPP (7.9 ± 0.9 years) were treated with triptorelin 11.25 mg/90 days. Methods. Gonadotropins, basal-, and GnRH-stimulated peak, gonadal steroids, and pubertal signs were assessed at preinclusion and at inclusion visit, 3 months, 6 months, and 12 months of treatment. Results. At 3, 6, and 12 months, all patients had suppressed LH peak (<3 IU/L after GnRH stimulation), as well as prepubertal oestradiol levels. Mean LH peak values after GnRH test significantly decreased from 25.7 ± 16.5 IU/L at baseline to 0.9 ± 0.5 IU/L at M3 (P < 0.0001); they did not significantly changed at M6 and M12. Conclusions. Triptorelin 11.25 mg/90 days efficiently suppressed the pituitary-gonadal axis in children with CPP from first administration

    YAP enhances the pro-proliferative transcriptional activity of mutant p53 proteins

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    Mutant p53 proteins are present in more than half of human cancers. Yes-associated protein (YAP) is a key transcriptional regulator controlling organ growth, tissue homeostasis, and cancer. Here, we report that these two determinants of human malignancy share common transcriptional signatures. YAP physically interacts with mutant p53 proteins in breast cancer cells and potentiates their pro-proliferative transcriptional activity. We found YAP as well as mutant p53 and the transcription factor NF-Y onto the regulatory regions of cyclin A, cyclin B, and CDK1 genes. Either mutant p53 or YAP depletion down-regulates cyclin A, cyclin B, and CDK1 gene expression and markedly slows the growth of diverse breast cancer cell lines. Pharmacologically induced cytoplasmic re-localization of YAP reduces the expression levels of cyclin A, cyclin B, and CDK1 genes both in vitro and in vivo. Interestingly, primary breast cancers carrying p53 mutations and displaying high YAP activity exhibit higher expression levels of cyclin A, cyclin B, and CDK1 genes when compared to wt-p53 tumors

    Lipidomic analysis of roseobacters of the pelagic RCA cluster and their response to phosphorus limitation

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    The marine roseobacter-clade affiliated cluster (RCA) represents one of the most abundant groups of bacterioplankton in the global oceans, particularly in temperate and sub-polar regions. They play a key role in the biogeochemical cycling of various elements and are important players in oceanic climate-active trace gas metabolism. In contrast to copiotrophic roseobacter counterparts such as Ruegeria pomeroyi DSS-3 and Phaeobacter sp. MED193, RCA bacteria are truly pelagic and have smaller genomes. We have previously shown that RCA bacteria do not appear to encode the PlcP-mediated lipid remodeling pathway, whereby marine heterotrophic bacteria remodel their membrane lipid composition in response to phosphorus (P) stress by substituting membrane glycerophospholipids with alternative glycolipids or betaine lipids. In this study, we report lipidomic analysis of six RCA isolates. In addition to the commonly found glycerophospholipids such as phosphatidylglycerol (PG) and phosphatidylethanolamine (PE), RCA bacteria synthesize a relatively uncommon phospholipid, acylphosphatidylglycerol, which is not found in copiotrophic roseobacters. Instead, like the abundant SAR11 clade, RCA bacteria upregulate ornithine lipid biosynthesis in response to P stress, suggesting a key role of this aminolipid in the adaptation of marine heterotrophs to oceanic nutrient limitation
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