342 research outputs found

    Structure-function analysis of RNA polymerase II

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    Sites of strong Rec12/Spo11 binding in the fission yeast genome are associated with meiotic recombination and with centromeres

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    Meiotic recombination arises from Rec12/Spo11-dependent formation of DNA double-strand breaks (DSBs) and their subsequent repair. We identified Rec12-binding peaks across the Schizosaccharomyces pombe genome using chromatin immunoprecipitation after reversible formaldehyde cross-linking combined with whole-genome DNA microarrays. Strong Rec12 binding coincided with previously identified DSBs at the recombination hotspots ura4A, mbs1, and mbs2 and correlated with DSB formation at a new site. In addition, Rec12 binding corresponded to eight novel conversion hotspots and correlated with crossover density in segments of chromosome I. Notably, Rec12 binding inversely correlated with guanine-cytosine (GC) content, contrary to findings in Saccharomyces cerevisiae. Although both replication origins and Rec12-binding sites preferred AT-rich gene-free regions, they seemed to exclude each other. We also uncovered a connection between binding sites of Rec12 and meiotic cohesin Rec8. Rec12-binding peaks lay often within 2.5kb of a Rec8-binding peak. Rec12 binding showed preference for large intergenic regions and was found to bind preferentially near to genes expressed strongly in meiosis. Surprisingly, Rec12 binding was also detected in centromeric core regions, which raises the intriguing possibility that Rec12 plays additional roles in meiotic chromosome dynamic

    Association of Excessive Sleepiness, Pathological Fatigue, Depression, and Anxiety With Different Severity Levels of Obstructive Sleep Apnea

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    Objective: The aim of this study was to investigate possible associations between obstructive sleep apnea and fatigue. This naturally led to considering the association between OSA and excessive sleepiness, depression, and anxiety. Background: OSA is a highly prevalent sleep disorder, associated with a risk of hypertension, cardiovascular events, daytime sleepiness, poor cognitive function, and sudden death during sleep. Both excessive sleepiness, fatigue, and symptoms of depression are frequently reported. Method: 5,464 patients referred to a university hospital for obstructive sleep apnea underwent standard respiratory polygraphy. The severity of OSA was defined as either mild, moderate, or severe, using the apnea–hypopnea index. Validated questionnaires were used to assess excessive sleepiness, pathological fatigue, depression, and anxiety. Results: Nearly 70% of the patients were men, and median age was 50 (range: 16–89) years. One in three had moderate-to-severe OSA (AHI ≥ 15). Excessive sleepiness and pathological fatigue were present in 43 and 39%, respectively. The prevalence of possible depression and anxiety was 19 and 28%, respectively. The proportion of patients with male sex, obesity, and excessive sleepiness increased with the severity of OSA. In contrast, the proportion of patients with pathological fatigue did not increase with OSA severity, and there was a decrease in depression and anxiety with increasing OSA severity. Conclusion: Our study reports that pathological fatigue, as well as anxiety and depression, did not increase with OSA severity, whereas excessive sleepiness did. Knowledge concerning conditions related to OSA severity may be indicative of pretest probability of OSA and thus change the priority for polygraphy. Furthermore, the high prevalence rates of fatigue, anxiety, and depression among these patients warrant further investigations.publishedVersio

    Test-retest reliability of the Shape/Texture Identification testTM in people with chronic stroke

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    To evaluate the test-retest reliability of the Shape/Texture Identification test (STI-test(TM)) in persons with chronic stroke

    Xonotlite and hillebrandite as model compounds for calcium silicate hydrate seeding in cementitious materials

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    The demand for more environmentally friendly cement with no disadvantages in relation to hydration activity has led to the development of various additives to accelerate cement hydration. As calcium silicate hydrate (C-S-H) is the major hydration product of cement and is responsible for its mechanical properties, it plays an outstanding role in the discussion of nanoparticle additives. Nevertheless, the investigation of its mechanism of action is complicated by the similarity of its properties to those of the C-S-H that forms as an initial hydration product. Crystalline C-S-H phases, on the other hand, can be easily distinguished from the original hydration products, which makes them a valuable model compound for studying the mechanisms of nucleation seeding in cementitious materials. In this paper, the effect of crystalline types of C-S-H as nucleation seeds are presented. Xonotlite and hillebrandite were thoroughly characterized using nuclear magnetic resonance, X-ray diffractometry (XRD), scanning electron microscopy (SEM), and infrared spectroscopy (IR) and were then used as an admixture for alite pastes. Low-vacuum SEM images of the hydrated pastes revealed that xonotlite can significantly promote the visible etch pit formation on C3S clinker particles, which was not found to be true for hillebrandite. Whether the phases act as a nucleation site is assumed to be strongly dependent on the mineralogy: hillebrandite appeared to be heavily overgrown, but xonotlite did not show any hydration products on its surfaces after the same hydration time of up to 24 h. The diverse effect of the minerals was confirmed by the accelerating behavior in isothermal heat flow calorimetry and by XRD

    Grundlagen und Qualifikationen soziologischer Beratung

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    Der Beitrag greift die auf der IX. Tagung für Angewandte Soziologie 'Soziologische Beratung' geführten intensiven Diskussionen um Profil, Aufgabengebiete und Qualifikationen von Beratern und Beraterinnen auf. Geklärt werden sollen die Begriffe 'soziologische Beratung' und 'soziologische Beratungskompetenz'. Ziel ist dabei, über Chancen und Risiken der Präzisierung und Standardisierung eines Berufsfeldes für Soziologen nachzudenken und zu eruieren, welche Möglichkeiten soziologische Beratung eröffnen kann bzw. wo und wie sich soziologische Beratung gegen andere Beratung abgrenzt. Damit wird letztendlich ein Orientierungsrahmen für eine systematische Qualifizierung in soziologischer Beratung geschaffen und gegenüber der Öffentlichkeit das Leistungsspektrum soziologischer Beratung transparenter und attraktiver gemacht.(ICH

    Structure–function studies of the RNA polymerase II elongation complex

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    X-ray crystallographic and complementary functional studies have contributed significantly to the current understanding of gene transcription. Here, recent structure–function studies on various aspects of the elongation phase of transcription are summarized
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