5,230 research outputs found

    Increased levels of RNA oxidation enhance the reversion frequency in aging pro-apoptotic yeast mutants

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    Despite recent advances in understanding the complexity of RNA processes, regulation of the metabolism of oxidized cellular RNAs and the mechanisms through which oxidized ribonucleotides affect mRNA translation, and consequently cell viability, are not well characterized. We show here that the level of oxidized RNAs is markedly increased in a yeast decapping Kllsm4Δ1 mutant, which accumulates mRNAs, ages much faster that the wild type strain and undergoes regulated-cell-death. We also found that in Kllsm4Δ1 cells the mutation rate increases during chronological life span indicating that the capacity to han- dle oxidized RNAs in yeast declines with aging. Lowering intracellular ROS levels by antioxidants recovers the wild- type phenotype of mutant cells, including reduced amount of oxidized RNAs and lower mutation rate. Since mRNA oxidation was reported to occur in different neurodegen- erative diseases, decapping-deficient cells may represent a useful tool for deciphering molecular mechanisms of cell response to such conditions, providing new insights into RNA modification-based pathogenesis

    Structural aspects of the female sexual differentiation of the pirarucu (Arapaima gigas, SCHINZ, 1822).

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    The pirarucu (Arapaima gigas) are the biggest scale Amazonian fish and their farming potential is enormous. However, there are few studies involving the reproductive physiology of pirarucu. Raising fish in confined environments still encounters several adversities, being necessary basic studies for the development of the productive chain, mainly at the early stages of development. Thus, studies related to the gonadal development are essential for the understanding of the reproductive biology of the species

    A device to characterize optical fibres

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    ATLAS is a general purpose experiment approved for the LHC collider at CERN. An important component of the detector is the central hadronic calorimeter; for its construction more than 600,000 Wave Length Shifting (WLS) fibres (corresponding to a total length of 1,120 Km) have been used. We have built and put into operation a dedicated instrument for the measurement of light yield and attenuation length over groups of 20 fibres at a time. The overall accuracy achieved in the measurement of light yield (attenuation length) is 1.5% (3%). We also report the results obtained using this method in the quality control of a large sample of fibres.Comment: 17 pages 20 figeres submitted to NIM journa

    Analytical and Numerical Characterization of Cherenkov Diffraction Radiation as a Longitudinal Electron Bunch Profile Monitor for AWAKE Run 2

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    In this paper, CST simulations of the coherent Cherenkov Diffraction Radiation with a range of parameters for different dielectric target materials and geometries are discussed and compared with the theoretical investigation of the Polarization Current Approach to design a prototype of a radiator for the bunch length/profile monitor for AWAKE Run 2. It was found that the result of PCA theory and CST simulation are consistent with each other regarding the shape of the emitted ChDR cone

    Optimization Study of Beam Position and Angular Jitter Independent Bunch Length Monitor for Awake Run 2

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    In this paper, a study using the Polarization Current Approach (PCA) model is performed to optimize the design of a short bunch length monitor using two dielectric radiators that produce coherent Cherenkov Diffraction Radiation (ChDR). The electromagnetic power emitted from each radiator is measuring a different part of the bunch spectrum using Schottky diodes. For various bunch lengths, the coherent ChDR spectrums are calculated to find the most suitable frequency bands for the detection system. ChDR intensities measured by each detector are estimated for different impact parameters to explore the dependence of bunch length monitor on beam position and angular jitter. It is found that, in the present configuration, the effects of beam position and angular jitter are negligibly small for bunch length measurement

    Measuring and explaining the diversity of voices and viewpoints in the news

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    News media can be considered to fulfil their democratic role as a “marketplace of ideas” only if they present a diverse content that gives space to a wider range of ideas and viewpoints. But how can content diversity be assessed? And what determines actor and viewpoint diversity in the first place? By employing measurements of actor and viewpoint diversity at the article and newspaper level, this study provides a complete overview on the content diversity of immigration news, and it investigates factors that have an impact on content diversity of immigration newspaper articles in Belgium, Germany, Italy and the United Kingdom (2013-2014). The results of a multilevel analysis indicate that both the articles’ size and the elite character of a newspaper play a key role in enhancing news’ multiperspectivalness. Also, the findings show that these two measurements of content diversity are different yet related to each other

    Demography and selection shape transcriptomic divergence in field crickets

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    Gene flow, demography, and selection can result in similar patterns of genomic variation and disentangling their effects is key to understanding speciation. Here, we assess transcriptomic variation to unravel the evolutionary history of Gryllus rubens and Gryllus texensis, cryptic field cricket species with highly divergent mating behavior. We infer their demographic history and screen their transcriptomes for footprints of selection in the context of the inferred demography. We find strong support for a long history of bidirectional gene flow, which ceased during the late Pleistocene, and a bottleneck in G. rubens consistent with a peripatric origin of this species. Importantly, the demographic history has likely strongly shaped patterns of genetic differentiation (empirical F-ST distribution). Concordantly, F-ST-based selection detection uncovers a large number of outliers, likely comprising many false positives, echoing recent theoretical insights. Alternative genetic signatures of positive selection, informed by the demographic history of the sibling species, highlighted a smaller set of loci; many of these are candidates for controlling variation in mating behavior. Our results underscore the importance of demography in shaping overall patterns of genetic divergence and highlight that examining both demography and selection facilitates a more complete understanding of genetic divergence during speciation

    The incidence and intensity of postendodontic pain and flareup in single and multiple visit root canal treatments: a systematic review and meta-analysis

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    To assess the incidence and intensity of postendodontic pain and flareup in single and multiple visit root canal treatment (RCT) and determine if the difference between the two is significant, a search of PubMed, Medline, Embase, Cochrane, Scopus and Web of science was conducted. The grey literature was searched using Google Scholar and Saudi digital library. Randomised controlled trials evaluating the incidence and intensity of postendodontic pain and flareup published in English from 1 January 2000 to 15 April 2020 were searched. The PRISMA protocol was followed to select the articles. A random effects model was used for the meta-analysis of the data in the included studies. Twenty-one articles were included in the review. Three compared both the incidence and the intensity, while the rest compared either one of the parameters. Most studies used both hand-driven and rotary instruments and irrigated with sodium hypochlorite. Twelve studies used an intracanal medicament. Although individual studies showed discordant treatment outcomes, the meta-analysis did not reveal any significant difference in the incidence or the intensity of the postendodontic flareup between the single and multiple visit RCT groups. Single or a multiple visit root canal treatment is not an independent determinant for the risk of postendodontic pain or a flareup

    Long-term bond strength and endogenous enzymatic activity of a chlorhexidine-containing commercially available adhesive

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    10siObjectives: The aim of this study was to investigate, by the means of microtensile bond strength (μTBS) test, gelatin and in situ zymography, the influence of 0.2% CHX contained within a commercially available adhesive on long-term bond strength and endogenous enzymatic activity. Methods: Non-carious teeth were subjected to μTBS test (N = 15 for each group) and stressed until failure. μTBS was evaluated immediately and after 12-month storage in artificial saliva at 37 °C. Dentin powder was obtained from additional teeth (N = 7) for gelatin zymography, while for in situ zymography, 3 teeth for each group were selected. Gelatin and in situ zymography were performed in dentin powder and slices of dentin, respectively, to assess the ability of 0.2% CHX blended within the adhesive to inhibit endogenous enzymatic activity. Results: μTBS bond strength was higher in the CHX-containing groups, immediately as well as after aging. The bond strength significantly decreased after 12-month aging. The activation of endogenous MMPs was found to be related to the presence of CHX within the adhesive system and the bonding strategy employed. Conclusions: Under this perspective 0.2% CHX blended within Peak Universal adhesive monomer seems to in- crease immediate bond strength, to preserve bond strength over time and to efficiently inhibit endogenous enzymatic activity in dentin. Hence, blending the CHX in low concentrations within the adhesive could be recommended as a feasible technique in every-day clinical practice. Clinical significance: Using CHX-containing adhesives could be recommended due to several benefits: it seems to increase the longevity of the hybrid layer; the inhibitor appears to be efficiently delivered to the dentinal substrate and to inhibit endogenous enzymatic activity, without prolonging chair time.openopenMaravić, Tatjana; Comba, Allegra; Cunha, Sandra Ribeiro; Angeloni, Valeria; Cadenaro, Milena; Visinitini, Erika; Navarra, Chiara Ottavia; Salgarello, Stefano; Breschi, Lorenzo*; Mazzoni, AnnalisaMaravić, Tatjana; Comba, Allegra; Cunha, Sandra Ribeiro; Angeloni, Valeria; Cadenaro, Milena; Visinitini, Erika; Navarra, Chiara Ottavia; Salgarello, Stefano; Breschi, Lorenzo; Mazzoni, Annalis

    Experimental Observation of “Shadowing” in Optical Transition Radiation

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    We report the observation of shadowing between two optical transition radiation (OTR) sources from a 205 MeV electron beam. The total optical intensity is measured as a function of the distance dd between the sources, covering the range 0<d<4Lν0 \lt d \lt 4L_{\nu}, where LνL_{\nu} is the formation length of the particles. Data show that the total optical intensity starts decreasing due to shadowing when dd approaches LνL_{\nu} until it becomes undetectable for very short distances d/Lν→0d/L_{\nu} \rightarrow 0. A model based solely on interference between the two OTR sources is in good agreement with experimental data. To the knowledge of the authors this is the first systematic experimental observation of shadowing in OTR
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