828 research outputs found

    Broadening the mission of an RNA enzyme

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    The “RNA World” hypothesis suggests that life developed from RNA enzymes termed ribozymes, which carry out reactions without assistance from proteins. Ribonuclease (RNase) P is one ribozyme that appears to have adapted these origins to modern cellular life by adding protein to the RNA core in order to broaden the potential functions. This RNA-protein complex plays diverse roles in processing RNA, but its best-understood reaction is pre-tRNA maturation, resulting in mature 5' ends of tRNAs. The core catalytic activity resides in the RNA subunit of almost all RNase P enzymes but broader substrate tolerance is required for recognizing not only the diverse sequences of tRNAs, but also additional cellular RNA substrates. This broader substrate tolerance is provided by the addition of protein to the RNA core and allows RNase P to selectively recognize different RNAs, and possibly ribonucleoprotein (RNP) substrates. Thus, increased protein content correlated with evolution from bacteria to eukaryotes has further enhanced substrate potential enabling the enzyme to function in a complex cellular environment. J. Cell. Biochem. 108: 1244–1251, 2009. © 2009 Wiley-Liss, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/64531/1/22367_ftp.pd

    Visual Analysis of Spatio-Temporal Event Predictions: Investigating the Spread Dynamics of Invasive Species

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    Invasive species are a major cause of ecological damage and commercial losses. A current problem spreading in North America and Europe is the vinegar fly Drosophila suzukii. Unlike other Drosophila, it infests non-rotting and healthy fruits and is therefore of concern to fruit growers, such as vintners. Consequently, large amounts of data about infestations have been collected in recent years. However, there is a lack of interactive methods to investigate this data. We employ ensemble-based classification to predict areas susceptible to infestation by D. suzukii and bring them into a spatio-temporal context using maps and glyph-based visualizations. Following the information-seeking mantra, we provide a visual analysis system Drosophigator for spatio-temporal event prediction, enabling the investigation of the spread dynamics of invasive species. We demonstrate the usefulness of this approach in two use cases

    Wasting away in Mars-Aritaville

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    Anisotropic Carbon Nanotube Structures with High Aspect Ratio Nanopores for Li-Ion Battery Anodes.

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    Technological advances in membrane technology, catalysis, and electrochemical energy storage require the fabrication of controlled pore structures at ever smaller length scales. It is therefore important to develop processes allowing for the fabrication of materials with controlled submicron porous structures. We propose a combination of colloidal lithography and chemical vapor deposition of carbon nanotubes to create continuous straight pores with diameters down to 100 nm in structures with thicknesses of more than 300 ÎŒm. These structures offer unique features, including continuous and parallel pores with aspect ratios in excess of 3000, a low pore tortuosity, good electrical conductivity, and electrochemical stability. We demonstrate that these structures can be used in Li-ion batteries by coating the carbon nanotubes with Si as an active anode material

    Nutzen der Digitalisierung auf eine nachhaltige Landschafts- und Raumentwicklung: Ergebnisse einer breit angelegten Delphi-Umfrage in der Schweiz

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    Digitalisierung verĂ€ndert die Anforderungen an den Raum, dessen Nutzungen und damit Raum und Landschaft selbst. FĂŒr Technik und Fachplanungen kristallisieren sich die Entwicklungstrends allmĂ€hlich heraus. Doch wie sich die Digitalisierung auf den Raum und die Planung konkret auswirkt, ist momentan noch kaum erforscht. Auswirkungen der Digitalisierung werden in den Bereichen MobilitĂ€t, Energie und Versorgung besonders deutlich, aber auch in Bezug auf Freizeit und Erholung und die flĂ€chenhaften Nutzungen werden Trends in der Fachwelt diskutiert.Hier erste Antworten und Hilfestellungen fĂŒr die Planung in den Gemeinden und Regionen zu finden, um deren HandlungsfĂ€higkeit im Zeitalter der Digitalisierung zu erhöhen, ist Ziel des Forschungsprojekts „NUDIG – Nutzen der Digitalisierung fĂŒr eine nachhaltige Landschafts- und Raumentwicklung“ der HSR Hochschule fĂŒr Technik Rapperswil / Schweiz. Als Grundlage werden im ersten Schritt aus der Literatur und aus beschriebene Auswirkungen der Digitalisierung vom Forschungsteam systematisiert und bewertet. Als Ergebnis der Desktoprecherche kann die Raumwirksamkeit der Digitalisierung und mögliche SteuerungsansĂ€tze phĂ€nomenologisch beschrieben werden, eine Evidenz oder sogar Empirie ĂŒber die Raumwirksamkeit lĂ€sst sich hingegen nicht ableiten. Eine empirische Untersuchung der Raumwirksamkeit der Digitalisierung, die sich mit mehreren Disziplinen der rĂ€umlichen Planung und deren Wechselwirkungen befasst, scheint zumindest zum jetzigen Zeitpunkt nicht möglich. Um die Ergebnisse und die darausfolgenden Thesen der Literaturrecherche dennoch zu plausibilisieren wurde eine zweifstufige Delphi-Umfrage gestartet, wo Fachexpertinnen und Fachexperten der einzelnen Planungsdisziplinen gefragt sind,ihre EinschĂ€tzungen zu den Auswirkungen und dem Nutzen der Digitalisierung auf die Planung abzugeben. Das zentrale Ergebnis der Umfrage ist, dass sich die Fachdisziplinen der Digitalisierung nicht verweigern können und die Raumnutzungen und die Wahrnehmung von Raum beeinflusst und verĂ€ndert werden. Die Digitalisierung eröffnet fĂŒr alle Raumkategorien und die unterschiedlichen Fachdisziplinen Potenziale fĂŒr eine nachhaltige Entwicklung, wenngleich die einzelnen positiven und auch negativen EinschĂ€tzungen derFachdisziplinen variieren. Dieser Beitrag soll daher einerseits die Vorgehensweise der Delphi-Umfrage beleuchten sowie die relevantesten Ergebnisse und Schlussfolgerungen aus der Umfrage erlĂ€utern. Andererseits liegt der Fokus auf der Frage ob mithilfe der Digitalisierung und der dadurch entstehenden neuen planerischen Perspektiven, eine Trendumkehr, eine umweltvertrĂ€glichere und ressourceneffizientere Raum-, Verkehrs- und Landschaftsplanung, unterstĂŒtzt und wie dieser Aspekt von der Fachwelt beurteilt wird

    Intra-oral compartment pressures: a biofunctional model and experimental measurements under different conditions of posture

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    Oral posture is considered to have a major influence on the development and reoccurrence of malocclusion. A biofunctional model was tested with the null hypotheses that (1) there are no significant differences between pressures during different oral functions and (2) between pressure measurements in different oral compartments in order to substantiate various postural conditions at rest by intra-oral pressure dynamics. Atmospheric pressure monitoring was simultaneously carried out with a digital manometer in the vestibular inter-occlusal space (IOS) and at the palatal vault (sub-palatal space, SPS). Twenty subjects with normal occlusion were evaluated during the open-mouth condition (OC), gently closed lips (semi-open compartment condition, SC), with closed compartments after the generation of a negative pressure (CCN) and swallowing (SW). Pressure curve characteristics were compared between the different measurement phases (OC, SC, CCN, SW) as well as between the two compartments (IOS, SPS) using analysis of variance and Wilcoxon matched-pairs tests adopting a significance level of α = 0.05. Both null hypotheses were rejected. Average pressures (IOS, SPS) in the experimental phases were 0.0, −0.08 (OC); −0.16, −1.0 (SC); −48.79, −81.86 (CCN); and −29.25, −62.51 (SW) mbar. CCN plateau and peak characteristics significantly differed between the two compartments SPS and IOS. These results indicate the formation of two different intra-oral functional anatomical compartments which provide a deeper understanding of orofacial biofunctions and explain previous observations of negative intra-oral pressures at rest

    Segmentation of the fascia lata and reproducible quantification of intermuscular adipose tissue (IMAT) of the thigh

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    Abstract Objective To develop a precise semi-automated segmentation of the fascia lata (FL) of the thigh to quantify IMAT volume in T1w MR images and fat fraction (FF) in Dixon MR images. Materials and methods A multi-step segmentation approach was developed to identify fibrous structures of the FL and combining them into a closed 3D surface. 23 healthy young men with low and 50 elderly sarcopenic men with moderate levels of IMAT were measured by T1w and 6pt Dixon MRI at 3T. 20 datasets were used to determine reanalysis precision errors. IMAT volume was compared using the new FL segmentation versus an easier to segment but less accurate, tightly fitting envelope of the thigh muscle ensemble. Results The segmentation was successfully applied to all 73 datasets and took about 7 min per 28 slices. In particular, in elderly subjects, it includes a large amount of adipose tissue below the FL typically not accounted for in other segmentation approaches. Inter- and intra-operator RMS-CVs were 0.33% and 0.14%, respectively, for IMAT volume and 0.04% and 0.02%, respectively, for FFMT. Discussion The FL segmentation is an important step to quantify IMAT with high precision and may be useful to investigate effects of aging and treatment on changes of IMAT and FF. ClinicalTrials.gov identifier NCT2857660, August 5, 2016. Trial registration ClinicalTrials.gov identifier NCT2857660, August 5, 2016
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