386 research outputs found

    Aluminum Sheet Metal Damage Mechanisms Application to Trimming and Hemming

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    Aluminum alloys are increasingly used in automotive structural applications thanks to their combination of low density, high strength, and good formability. Appropriate strength levels for dent resistant automotive aluminum panels may be achieved by a combination of alloy design and thermo-mechanical treatments. Unfortunately, increased strength (hardness) generally limits homogeneous plastic deformation. Thus, when shaping complex components large deformation and eventually strain localization, necking and final failure is more likely to occur. In this chapter, we endeavor to explore the best compromises between increased hardening and satisfying formability. Sheet metal shaping generates large strains and eventually strain localization. The accurate measure of metal behavior is discussed first. The following section is dedicated to the kinetics of damage development during shaping. Then metal ductility at low stress triaxiality and consequent strain localization are discussed. Finally, trimming and hemming, the most complex shaping operations to perform efficiently are analyzed providing a powerful tool for alloy design

    Frequency and causes of kangaroo-vehicle collisions on an Australian outback highway

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    Kangaroo-vehicle collisions are frequent on Australian highways. Despite high economic costs, detrimental effects on animal welfare, and potential impacts on population viability, little research has been done to investigate the impact of road mortality on kangaroo populations, where and why accidents occur, and how the collisions can be mitigated. We therefore collected data on species (Macropus rufus, M. giganteus, M. fuliginosus, M. robustus), sex and age of kangaroos killed on a 21.2-km bitumenised section of outback highway over 6 months in far western New South Wales, Australia. The spatial and temporal distribution of road-killed kangaroos was investigated in relation to the cover and quality of road-side vegetation, road characteristics, the density of kangaroos along the road, climatic variables and traffic volume. A total of 125 kangaroos were found killed on the road at a rate of 0.03 deaths km-1 day-1. Grey kangaroos of two species (M. giganteus, M. fuliginosus) were under-represented in the road-kill sample in comparison with their proportion in the source population estimated during the day. No bias towards either sex was found. The age structure of road-killed kangaroos was similar to age structures typical of source kangaroo populations. Road-kills mainly occurred in open plains country. In road sections with curves or stock races, road-kill frequencies were higher than expected. Greater cover and greenness of roadside vegetation at the verge probably attracted kangaroos to the road and variation in this vegetation affected the spatial distribution of road-kills. The temporal distribution of road-kills was positively correlated with the volume of night-time traffic. The probability of a kangaroo-vehicle collision increased exponentially with traffic volume. Results are discussed in relation to the potential for mitigation of kangaroo-vehicle collisions. © CSIRO 2006

    A sequence motif responsible for ER export and surface expression of Kir2.0 inward rectifier K+ channels

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    AbstractIntegral membrane proteins are sorted via the secretory pathway. It was proposed that this pathway is non-selective provided that the cargo protein is properly assembled and lacks an endoplasmic reticulum (ER) retention signal. However, recent experimental evidence suggests that efficient export of proteins from the ER to the Golgi complex is not simply a default pathway. Here we demonstrate a novel sequence motif (FxYENEV) in the cytoplasmic C-terminus of mammalian inward rectifier potassium (Kir) channels which determines ER export. This motif is found to be both necessary and sufficient for efficient export from the ER that eventually leads to efficient surface expression of Kir2.1 channels

    Regionale Katholikentage nach dem Ersten Weltkrieg: konservative Massenmobilisierung zwischen 'Tradition' und 'Moderne'

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    'Die fast vergessenen regionalen Katholikentage nach dem Ersten Weltkrieg in Deutschland weiteten das Organisationsmuster der gesamtdeutschen Katholikentage ĂŒber das ganze Land bis in lĂ€ndliche Regionen aus und sendeten nach außen und innen Signale der angeblich 'einmĂŒtigen' Macht und Orientierungsgewissheit. Kontinuierliches Beharren auf FĂŒhrung durch die kirchliche Hierarchie paarte sich mit graduell erweiterter Mitwirkung des Kirchenvolkes. Aspektreich, detailliert (am Beispiel der Kölner Erzdiözese) und kritisch werden die Modernisierungen von Vereinskultur, Politischer Kultur, Festkultur wie auch die inhaltlichen Akzentsetzungen analysiert.' (Autorenreferat)'The regional German Katholikentage after WWI are nearly forgotten. However, they also had an impact on the national Katholikentage: they broadened their organisation pattern all over the country even to rural regions and sent out signals to the inside and outside about the assumed unanimous ('einmĂŒtig') power and certainty of orientation. Continuous insistence on leadership of the church hierarchy was combined with a gradual enlarged participation of the church members. The political culture (Politische Kultur), the culture of clubs (Vereinskultur), the culture of festivities (Festkultur) as well as the emphasized statements (the archbishopric of Cologne serves as the example) are detailed and critically analysed.' (author's abstract

    Revision der Gattung Amphidium (Musci, Dicranaceae)

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    Only 3 of the 13 species so far comprised in Amphidium were retained in the genus: A lapponicum (Hedw.) Schimp., A. mougeotii (B.S.G.) Schimp. and A. tortuosum (Hornschuch) Cufodontis. Amphidium. sublapponicum (C. MĂŒll.) Broth. is conspecific with A. lapponicum, A. cyathicarpum (Mont.) Broth., A. curvipes (C. MĂŒll.) Broth. and A. californicum (C. MĂŒll.) Broth. are synoymous with A. tortuosum. Amphidium brevifolium Broth., A. clastophyllum Broth. and A. papillosum Broth., all known only from the type locality, are sterile and differ vegetatively from all other species of the genus. They belong probably not to Amphidium. The types of Amphidium letestui ThĂ©r. & P. Varde, A. aloysii-sabaudiae Negri and A. remotidens (C. MĂŒll.) Broth. could not be located.Von den 13 bisher in der Gattung Amphidium eingeschlossenen Arten konnten nur 3 mit Sicherheit als zur Gattung gehörig bestimmt werden, nĂ€mlich A. lapponicum (Hedw.) Schimp., A. mougeotii (B.S.G.) Schimp.und A.tortuosum (Hornschuch) Cufodontis. A. sublapponicum (C. MĂŒll.) Broth. wird als Synonym von A. lapponicum, A. cyathicarpum (Mont.) Broth., A. curvipes (C. MĂŒll.) Broth. und A. californicum (C. MĂŒll.) Broth. werden als Synonyme von A. tortuosum angesehen. Alle ĂŒbrigen Arten konnten aufgrund fehlenden Herbarmaterials oder sterilen Typusmaterials nicht einwandfrei als zu Amphidium gehörig bezeichnet werden

    Hochfeld Magnet-Resonanz-Tomographie der WirbelsÀule bei 3,0 Tesla mit paralleler Bildgebung

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    Die Hochfeld-Magnetresonanztomograpie bei 3,0 Tesla (T) ist mittlerweile im klinischen Alltag etabliert. Als ihr grĂ¶ĂŸter Vorteil wird das erhöhte Signal-zu-Rausch VerhĂ€ltnis angesehen. Nachteilig kommt es zu einem schnelleren Erreichen der Grenze der Spezifischen-Absorption-Rate und erhöhter AnfĂ€lligkeit fĂŒr SuszeptibilitĂ€tsartefakte. Diese Probleme können heute durch Einsatz paralleler Bildgebungsverfahren wie Sensivity Encoding (SENSE) und Refokussierungstechniken (engl.: flip angle sweep, kurz: FAS) gelöst werden. Vor diesem Hintergrund untersucht die vorliegende Studie die HalswirbelsĂ€ule acht gesunder Probanden mittels einer Spule, die SENSE-fĂ€hig ist und eine VerĂ€nderung des Winkels des Refokussierungspulses erlaubt. Im ersten Teil werden unter VerĂ€nderung der Echozeit Aufnahmen bei 1,5 T und 3,0 T anhand des Parameters Kontrast miteinander verglichen. Im zweiten Teil werden unter kontinuierlicher VerĂ€nderung von Echozeit und Winkel des Refokussierungspulses Daten akquiriert und wiederum bezĂŒglich des Kontrastes verglichen. Die Datenauswertung erfolgte sowohl quantitativ unter Verwendung von explorativer Datenanalyse und Post-Hoc Analyse nach Bonferroni (SPSS, Version 14, excel, Version 2003), als auch qualitativ durch einen erfahrenen Radiologen. Die quantitative Betrachtung der Daten bei 1,5 T und 3,0 T ergab, dass die KontrastverhĂ€ltnisse bei 1,5 T durchschnittlich höher waren als bei 3,0 T. Im Vergleich der beiden FeldstĂ€rken unterschieden sich alle Kontraste bis auf Knochen-Myelon und Knochen-Liquor signifikant voneinander. Sowohl bei 1,5 T als auch bei 3,0 T lĂ€sst sich eine AbhĂ€ngigkeit der Kontrastes von der Echozeit erkennen: mit kĂŒrzer werdender Echozeit nimmt der Kontrast ab. Die qualitative Analyse zeigte, dass die Kontraste bei 3,0 T subjektiv besser bewertet wurden. Bei kontinuierlicher VerĂ€nderung der Echozeit und des Winkels des Refokussierungspulses, konnte festgestellt werden, dass sich statistisch die Echozeit 120 ms signifikant von den anderen Echozeiten abgrenzt und hier auch insgesamt die höchsten Kontraste zu verzeichnen waren. DarĂŒber hinaus zeigte sich ein deutlicher Abfall des Kontrastes ab den Winkeln 75° und kleiner. Dies wird durch die qualitative Beurteilung gestĂ€rkt, hier werden jedoch kĂŒrzere Echozeiten als ĂŒberlegen bewertet. Zusammenfassend lĂ€sst sich sagen, dass die Kombination von SENSE und FAS auch mit Variation der Echozeit eine klinisch einsetzbare Untersuchungstechnik darstellt, die gleichzeitig die Gesamtaufnahmedauer der Messsequenzen reduzieren kann

    Rasch-Built Measure of Pleasant Touch through Active Fingertip Exploration

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    Background: Evidence suggests that somatic sensation has a modality for pleasant touch. Objective: To investigate pleasant touch at the fingertip level (i.e., glabrous skin site) through the elaboration of a linear unidimensional scale that measures (i) various materials according to the level of pleasantness they elicit through active fingertip explorations and (ii) subjects according to their pleasantness leniency levels. Subjects: We enrolled 198 healthy subjects without any neurological disease. Methods: Blindfolded subjects actively explored 48 materials with their index fingertips and reported the perceived pleasantness of each on a 4-level scale. The fingertip moisture levels on each subject were measured before the experimental session. Data were analyzed using the Rasch model. Results: We elaborated unidimensional linear scale that included 37 materials according to their pleasantness of touch. The pleasantness level of 21 materials was perceived differently, depending on the fingertip moisture levels of the subjects. Conclusion: Based on our findings, we formulated a Pleasant Touch Scale. Fingertip moisture levels appeared to be a major factor for (un)pleasant feelings during active exploration

    Visitenstruktur einer intensivmedizinischen Station: Analyse unter lernpsychologischen Aspekten

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    In dieser prospektiven, objektiv beobachtenden Studie wurden die Informationsweitergabe und –verarbeitung einer intensivmedizinischen Visite auf einer universitĂ€ren Intensivstation untersucht. Die Datenerhebung erfolgte mittels Videoanalyse und Fragebögen. Ergebnisse: Es lĂ€sst sich ein deutlicher Informationsverlust innerhalb von 24 Stunden erkennen. Die Konzentration der Ärzte nimmt zum Ende der Visite ab. Die Ärzte können sich nur einen geringen Teil der genannten Informationen merken. Die Struktur der bisherigen Visite sollte aus lernpsychologischer Sicht ĂŒberdacht werden.We conducted a prospective, observational study in the Intensive Care Unit of a university clinic with 18 beds. The information transfer and process of ward rounds was analyzed with the help of video recordings and questionnaires. Results: A major loss of information was discovered. The physicians concentration decreased towards the end of the ward round. The physicians could only remember a small amount of information. This study shows that the structure of the ward round as it is organized up until now needs to be reconsidered

    Surgical Trauma Leads to a Shorter Survival in a Murine Orthotopic Pancreatic Cancer Model

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    Background: Abdominal surgery is frequently followed by immune dysfunction usually lasting for several days. This is especially important in cases with tumour diseases as an intact immune function is essential in this situation. Therefore, we analysed the outcome of tumour-bearing mice in a mouse model of surgically induced immune dysfunction (SID). Methods: In male C57BL/6 mice, a pancreatic tumour was implanted orthotopically. Following tumour implantation, the model of SID was applied. The control groups were either laparotomised or underwent no surgical procedure. The survival rate was determined by observation for >60 days. The tumour growth progress was imaged by a 7-tesla small animal MRI. Results: On day 60 after tumour implantation, the survival rate in SID mice was reduced to 41%. In the laparotomised group, 81% of mice survived, while the control group had a survival rate of 75%. These differences were significant (SID vs. control: p < 0.02, and SID vs. laparotomy: p < 0.002). The tumour volume was not influenced by the degree of surgical trauma. Conclusion: In pancreatic cancer, the SID model is ideally suited to investigate the influence of SID on this tumour entity
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