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  1. Die Tabellen von Ulugh Beg. Die Sternkataloge des Ptolemäus, Ulugh Beg und Tycho Brahe im Vergleich

    NASA Astrophysics Data System (ADS)

    Schwan, Heiner

    2002-09-01

    Im 15. Jahrhundert schuf Ulugh Beg, der Herrscher von Samarkand (1394 - 1449), ein wichtiges Tabellenwerk. Das Kernstück dieses Werks (Zij Ulugh Beg, "Tabellen Ulugh Begs") ist ein Katalog mit 1018 Sternen, ihren Helligkeiten und Positionen. In diesem Bericht werden die Zij Ulugh Beg mit den großen Katalogen von Ptolemäus und Tycho Brahe verglichen.

  2. Gesellschaft, Lebensgemeinschaft, Ökosystem - Über die Kongruenz von politischen und ökologischen Theorien der Entwicklung

    NASA Astrophysics Data System (ADS)

    Voigt, Annette

    Im Jahr 1859 veröffentlichte Charles Darwin "On the Origin of Species“. Seine Evolutionstheorie ist das wohl spektakulärste Beispiel einer naturwissenschaftlichen Theorie großer gesellschaftlicher Relevanz. Ihre verschiedenen Facetten wurden in der Öffentlichkeit kontrovers diskutiert, unter anderem auch ihre Anwendung zur Erklärung von Zuständen und Prozessen menschlicher Gesellschaften. Zum Teil wurde die Seiensweise der Natur - scheinbar unabhängig von gesellschaftlichen Interessen - für die Erklärung und Legitimation gesellschaftlicher Zustände oder die Legitimation von politischen Ideologien herangezogen (Sozialdarwinismus). Denn Gesellschaft funktioniere ja so, wie Darwin die Natur erklärt habe: es herrsche z. B. Konkurrenzkampf, Auslese und Arbeitsteilung, Erfolg hätten diejenigen, die sich an die Bedingungen am Besten anpassten.

  3. Fehler begehen - Mathematik verstehen Über die Bedeutung von Fehlern für das Verstehen

    NASA Astrophysics Data System (ADS)

    Käser, Udo

    Auch wenn eine historisch oder systematisch umfassende Darstellung zur Fehlerthematik bislang nicht vorliegt, ist die Idee, einer Fehleranalyse unter der Leitfrage, welche Fehler von Schülerinnen und Schülern aufgrund welcher epistemologischen Überzeugungen begangen werden, zentralen Raum für die Betrachtung von Verstehensprozessen einzuräumen, nicht neu. So ist es geradezu ein Charakteristikum einer modernen konstruktivistischen Didaktik, die eigenen Fehler von Lernenden als ihre individuellen Lerngelegenheiten zu begreifen, die einen wichtigen Motor für den subjektiven Lernfortschritt bilden. Diese Sichtweise wurzelt aus psychologischer Perspektive in Analysen in der Tradition Piagets, der in Abkehr von einer quantitativen, psychometrischen Beschreibung kognitiver Prozesse, wie sie sich zum Beispiel in Intelligenztheorien nach Binet findet, qualitativ zu beschreiben versuchte, in welcher Weise Kinder und Jugendliche denken und urteilen. Doch auch schon in der klassischen Philosophie sind entsprechende Ansätze zu finden. Prominente Beispiele hierfür sind die Idolenlehre Bacons und die Ideenlehre Platons.

  4. Interaktive Visualisierung von Abständen und Ausdehnungen anatomischer Strukturen für die Interventionsplanung

    NASA Astrophysics Data System (ADS)

    Rössling, Ivo; Cyrus, Christian; Dornheim, Lars; Hahn, Peter; Preim, Bernhard; Boehm, Andreas

    Im Rahmen der Interventionsplanung muss der Chirurg therapierelevante Entscheidungen auf Basis räumlicher Relationen anatomischer Strukturen treffen. Interaktive 3D-Visualisierungen unterstützen diesen Prozess qualitativ. Quantitative Fragestellungen (Tumorausdehnung, Infiltrationstiefe, etc.) erfordern die Integration einer Bemaßung, deren Nutzen wesentlich von einer geeigneten Darstellung abhängt. In dieser Arbeit haben wir allgemeine Kriterien für die Eignung von Visualisierungen von Bemaßungen in interaktiven 3D-Szenen erarbeitet. Daran orientierend haben wir verschiedene Varianten der Darstellung von Abständen und Ausdehnungen anatomischer Strukturen betrachtet und ihr Erscheinungsbild hierzu zweckmäßig parametrisiert. Die Ausprägungen dieser Darstellungsparameter wurden in einer Studie auf ihre visuellen Wirkung hin an Chirurgen evaluiert. Es zeigte sich, dass die befragten Mediziner höchsten Wert auf Kohärenz und klare Zuordnung der Bemaßung setzten und überraschenderweise dafür sogar Abstriche in der direkten Lesbarkeit in Kauf nahmen.

  5. Wirkungen biogener Amine auf die Erregungs-Sekretions-Kopplung in der Speicheldrüse von Periplaneta americana (L.)

    NASA Astrophysics Data System (ADS)

    Rietdorf, Katja

    2003-07-01

    In der vorliegenden Arbeit habe ich wichtige Teilmechanismen der Erregungs-Sekretionskopplung in der Speicheldrüse der Schabe Periplaneta americana (L.) untersucht. Die Speicheldrüse ist von dopaminergen und serotonergen Fasern innerviert (Baumann et al., 2002). Beide Transmitter stimulieren eine unterschiedliche Reaktion der Drüse: Dopamin (DA) stimuliert die P-Zellen der Acini und die Ausführgangzellen, während Serotonin (5-HT) die P- und C-Zellen der Acini stimuliert, nicht jedoch die Ausführgangzellen. Der Endspeichel ist nach einer DA-Stimulierung proteinfrei. Dagegen enthält er nach einer 5-HT-Stimulierung Proteine, die von den C-Zellen sezerniert werden (Just & Walz, 1996). Im ersten Teil meiner Arbeit habe ich mittels Kapillarelektrophoretischer Analyse (CE-Analyse) die Elektrolytkonzentrationen im Endspeichel untersucht sowie die Raten der Flüssigkeitssekretion gemessen. Damit wollte ich klären, welche Transporter an der Sekretion des Primärspeichels und an dessen Modifikation beteiligt sind. Ausserdem wollte ich die Rolle der transportaktiven Epithelzellen der Ausführgänge für die Modifikation des Primärspeichels untersuchen. Dafür habe ich einen Vergleich der Elektrolytkonzentrationen im DA- und 5-HT-stimulierten Endspeichel durchgeführt. Der Elektrolytgehalt des DA- und 5-HT-stimulierten Endspeichels unterscheidet sich nicht signifikant voneinander. Er ist nach beiden Stimulierungen hypoosmotisch zum verwendeten Ringer. Die Ausführgangzellen werden durch DA stimuliert und modifizieren den Primärspeichel durch eine netto-Ionenreabsorption. Meine Versuche zeigen jedoch, dass auch die während einer 5-HT-Stimulierung der Drüse unstimulierten Ausführgangzellen den Primärspeichel modifizieren. In einer nachfolgenden Versuchsreihe habe ich den Einfluss von Ouabain, einem Hemmstoff der Na+-K+-ATPase, und Bumetanid, einem Hemmstoff des NKCC, auf die Raten der Flüssigkeitssekretion sowie den Elektrolytgehalt des Endspeichels untersucht. Ich

  6. Evolutionäre Algorithmen zur Topologieentwicklung von Neuronalen Netzen für die Roboter-Navigation im praktischen Einsatz

    NASA Astrophysics Data System (ADS)

    Köpsel, T.; Noglik, A.; Pauli, J.

    Eine wichtige Frage in der mobilen Robotik ist die sichere Navigation in unbekannten Umgebungen unter der Anwendung preiswerter Sensorik. Solch eine Navigation kann ein künstliches Neuronales Netz (kNN) übernehmen, welches die Kopplung der Sensoren des Roboters mit dessen Antriebssystem herstellt. "Neuro Evolution of Augmenting Topologies“ (NEAT) von Stanley und Miikkulainen [1] verwendet den Evolutionären Ansatz sowohl für die Topologieentwicklung, als auch für die Bestimmung der Gewichte eines kNN. NEAT hat sich als sehr gut, anpassungsfähig und relativ einfach in der Anwendung gezeigt. In diesem Beitrag wird NEAT in der Simulation angewendet, um ein kNN, das die Navigation des Roboters übernimmt, zu erhalten. Der Fokus liegt dabei auf der Erstellung der Fitnessfunktion und die Spezifikation und Durchführung einer realitätstreuen Simulation für den praktischen Einsatz. Die enge Verknüpfung von Realität und Simulationswelt hat entscheidend dazu beigetragen, dass der Umstieg aus der Simulation in die reale Welt ein Erfolg (höhere Anpassungsfähigkeit) wird. Dieser Artikel basiert auf der Diplomarbeit von [2].

  7. Charakterisierung von Sulfotransferasen im Gastrointestinaltrakt von Mensch und Ratte und Aktivierung von Promutagenen in V79-Zellen, die eine intestinale Form (1B1) des Menschen und der Ratte exprimieren

    NASA Astrophysics Data System (ADS)

    Teubner, Wera

    2001-05-01

    Die Ausstattung der gastrointestinalen Mukosa des Menschen und der Ratte mit Sulfotransferasen wurde mit Hilfe von Immunodetektion und Enzymaktivitätsmessungen untersucht. In Proben aus Colon und Rektum von 39 Personen wurden die Formen h1A1, h1A3 und h1B1 identifiziert, wobei in einer weiteren Probe, die als einzige von einem an Colitis Ulcerosa erkrankten Patienten stammte, keine Sulfotransferasen nachgewiesen werden konnten. Bei der Immunblot-Analyse war das Expressionsmuster der einzelnen Formen in allen Proben ähnlich. In wenigen Proben waren die relativen Signalintensitäten der h1A1 und der h1B1 um die Hälfte erniedrigt. Der Gehalt von SULT an zytosolischem Protein zeigte einen bis zu 8 - 10fachen Unterschied, er betrug jedoch bei zwei Dritteln der Proben zwischen 0,15 und 0,3 (h1A1 und h1A3) bzw. 0,6 und 0,8 Promille (h1B1). Die Variation konnte nicht auf Alter, Geschlecht oder Krankheitsbild der Patienten zurückgeführt werden. Auch der für die allelischen Varianten der h1A1 beschriebene Effekt auf die Enzymaktiviät bzw. Stabilität konnte in der Menge an immunreaktivem Protein nicht in diesem Ausma detektiert werden. Die Allelhäufigkeit von h1A1*R und h1A1*H war gegenüber der gesunden Bevölkerung nicht verändert. In den sieben Proben aus dem Dünndarm (Coecum, viermal Ileum, Jejunum) konnten zusätzlich die Formen h1E1 und h2A1 identifiziert werden. Ein möglicherweise der Form h1C1 entsprechendes Protein wurde im Magen detektiert. Im Vergleich zum Menschen war die Expression in der Ratte stärker auf die Leber konzentriert. Während beim Menschen in allen untersuchten Abschnitten Sulfotransferasen in Mengen detektiert wurden, die in zwei Fällen (h1B1 und h1A3) sogar den Gehalt in der Leber überstiegen, beschränkte sich die Expression in der Ratte auf im Vergleich zur Leber geringe Mengen im Magen und Dickdarm. Nachgewiesen wurden die r1B1, r1A1 sowie eine nicht identifizierte Form von 35kD, bei der es sich vermutlich um die r1C2 handelt. Im

  8. Die Struktur von schlankem Materialfluss mit Lean Production Kanban und Innovationen

    NASA Astrophysics Data System (ADS)

    Scheid, Wolf-Michael

    In der Literatur wird Materialfluss überwiegend in Spezialdisziplinen betrachtet, etwa der Steuerungslogik, der Logistiktechnik oder dem Supply Chain Management. Ein charakterisierendes Merkmal des Materialflusses ist jedoch, dass er sich aus vielfältigen Einzelbausteinen zusammensetzt, die alle harmonisch abgestimmt sein müssen. Die maximal erreichbare Effizienz wird nicht durch Höchstleistungen in dem einen oder anderen Spezialthema bestimmt, sondern durch das schwächste Glied im gesamten komplexen Netzwerk. Den Schnittstellen zwischen den betroffenen Fachbereichen in einem Unternehmen kommt hier eine ganz besondere Bedeutung zu: Erst ein harmonischer Einklang ermöglicht hohe Effektivität. Dies setzt umfassendes Verständnis für interdisziplinäre Notwendigkeiten, ein hohes Maß an Abstimmung mit den operativen Prozessen und letztlich einen einvernehmlichen Umgang und den Respekt vor den Problemstellungen des Anderen voraus.

  9. Increased expression of the von Hippel-Lindau gene in the implantation site of human tubal pregnancy.

    PubMed

    Xu, Jian-Ying; Zhu, Wei-Jie; Jiang, Huan

    2012-09-01

    The objective of this study was to investigate the expression of the von Hippel-Lindau (VHL) gene in tissues of human fallopian tube and tubal pregnancy. Twenty patients undergoing salpingectomy for tubal pregnancy were recruited into the study group. Tissues of tubal pregnancy were separated into both the implantation and non-implantation sites as the implantation group and the non-implantation group, respectively. Samples of ampullary fallopian tube during mid-secretory phase were collected from twenty patients with benign uterine disease as the control group. Immunohistochemistry, real-time reverse transcription polymerase chain reaction, and Western blotting analysis were performed to detect expressions of VHL mRNA and protein. The results showed that VHL immunostaining appeared in the cytoplasm of tubal epithelial cells. Expression of VHL mRNA in the implantation group was higher than that in the non-implantation group or the control group (P < 0.01). Intensity of VHL protein in the implantation group was increased compared with that in the non-implantation group (P < 0.05) or in the control group (P < 0.01). There was no difference on expressions of VHL mRNA and protein between the non-implantation group and the control group (P > 0.05). In conclusion, VHL mRNA and protein are present in human tubal tissues. The VHL gene expression is increased in the implantation site of tubal pregnancy, and locally elevated expression of the VHL gene might be associated with human tubal pregnancy.

  10. DIE BEWERTUNG VON OZONREAKTOREN

    EPA Science Inventory

    Evaluation of Ozone Reactors
    The use of lake water as drinking water resource involves a multistage treatment procedure. Food-related laws and regulations, in particular the food ordinance and the hygiene ordinance, require the identification and assessment of health risks, ...

  11. „Überholen ohne einzuholen“ Die Entwicklung von Technologien für übermorgen in Kernenergie und Mikroelektronik der DDR

    NASA Astrophysics Data System (ADS)

    Barkleit, Gerhard

    Dem nuklearen Patt zwischen Ostblock und westlichem Staatenbündnis ist es nach weitgehend übereinstimmender Auffassung von Politik und Wissenschaft zu danken, dass der "Kalte Krieg" in der zweiten Hälfte des 20. Jahrhunderts nicht zum weltumfassenden Flächenbrand eskalierte. An der raschen Herstellung dieses Patts waren zwei Dresdner Physiker maßgeblich beteiligt, deren einer im Manhattan-Projekt in den USA gearbeitet hatte und später in England der Spionage für die Sowjetunion und des Verrats des Know-how der Atombombe überführt wurde.

  12. Wege in die Zukunft

    NASA Astrophysics Data System (ADS)

    Kauermann, Göran; Mosler, Karl

    Die Zukunft stellt große Herausforderungen an die Arbeit der Deutschen Statistischen Gesellschaft. Sie betreffen die gestiegenen Anforderungen der Nutzer von Statistik, die Kommunikationsmöglichkeiten des Internets sowie die Dynamik der statistischen Wissenschaften und ihrer Anwendungsgebiete. Das Kapitel 5 beschreibt, wie sich die Gesellschaft diesen Herausforderungen stellt und welche Ziele sie sich in der wissenschaftlichen Zusammenarbeit und im Kampf gegen das Innumeratentum gesetzt hat.

  13. FEM and Von Mises analyses of different dental implant shapes for masticatory loading distribution

    PubMed Central

    CICCIÙ, M.; BRAMANTI, E.; CECCHETTI, F.; SCAPPATICCI, L.; GUGLIELMINO, E.; RISITANO, G.

    2014-01-01

    SUMMARY The rehabilitation of edentulous patients is today a challenge for the clinicians. The healthy of the hard and soft issue may be considered a fundamental element for having long-term results. The dental implant progresses about the predictable and safe results made this technique chosen from a large group of practitioners. However some problems related intra-operative and postoperative conditions may create discomfort on the patients and consequently to the clinician. The unfavourable results are often related to the bone tissue quality but sometime the dental implant shape and the prosthesis framework may undergo to technical difficulties. The purpose of this work is, through the use of appropriate FEM models, to analyse the effect of all these parameters in the construction of a prosthesis type “Toronto”, evaluating all the surgical and prosthetic components in order to direct the choices made by the surgeon and to optimize the distribution of loads reducing the patient’s discomfort and having a long term clinical success. PMID:25694795

  14. Indikatorenbasierte Bewertung von Entwurfsentscheidungen auf Systemebene

    NASA Astrophysics Data System (ADS)

    Freier, M.; Wenzler, A.; Mayer, T.; Gerlach, J.; Rosenstiel, W.

    2013-07-01

    Bei dem Entwurf von anwendungsspezifischen integrierten Schaltungen muss ein Entwickler zusätzliche Funktionen integrieren und die zunehmende Komplexität bewältigen. Für die Reduzierung der Kosten bleibt weiterhin die Verkürzung der benötigten Entwicklungszeit ein Ziel. Ein entscheidender Faktor dabei ist die zuverlässige Absicherung von Entwurfsentscheidungen in einer frühen Entwurfsphase. In der vorliegenden Arbeit wird eine Methode vorgestellt, die eine Bewertung von Entwurfsentscheidungen bei Systemmodellen mittels automatisch ermittelter Indikatoren ermöglichen soll. Die Systemmodelle können mit der Entwurfsumgebung MATLAB/Simulink oder in SystemC beschrieben sein.

  15. Verbesserung der Symmetrie von Hirnaufnahmen entlang der Sagittalebene

    NASA Astrophysics Data System (ADS)

    Ens, Konstantin; Wenzel, Fabian; Fischer, Bernd

    Die lokale Symmetrie von Hirnscans entlang der Sagittalebene zu ermitteln und zu modizifieren, ist für eine Reihe neurologischer Anwendungen interessant. Beispielsweise kann der voxelweise Vergleich von rechter und linker Hirnhälfte nur dann Aufschluss über die Lokalisierung von Läsionen geben, wenn durch Transformation ein Hirnscan eine möglichst hohe Symmetrie aufweist. Ein weiteres Anwendungsgebiet ist die Visualisierung von medialen Hirnschnitten, für die die Trennfläche beider Hirnhälfte möglichst eben sein sollte. Diese Arbeit stellt die Entwicklung eines Verfahrens vor, mit dessen Hilfe die Symmetrie von Hirnaufnahmen entlang der Sagittalebene verbessert werden kann. Dies geschieht unter Verwendung von aktiven Konturen, die mit Hilfe einer neuartigen Kostenfunktion gesteuert werden. Experimente am Ende der Arbeit mit strukturellen Kernspinaufnahmen demonstrieren die Leistungsfähigkeit des Verfahrens.

  16. Die moralischen Rechte von Kindern

    NASA Astrophysics Data System (ADS)

    Giesinger, Johannes

    2007-01-01

    THE MORAL RIGHTS OF CHILDREN - Most people today believe that children should be accorded legal or moral rights. In the course of the past few decades, however, objections to this view have been repeatedly raised. According to one objection, it is inappropriate for children to be the bearers of rights. Another group of objectors say that children's interests are not being served if rights are allocated to them. This paper acknowledges that rights alone are not enough to protect children's basic needs and interests in full. It is therefore inappropriate to resort to exclusively rights-based language when referring to the relationship between parents and children. Nevertheless, as this paper argues, it is advisable to provide children with moral rights. In response to the initial objection, a concept of rights is put forward which enables children, like adults, to be considered as the bearers of rights.

  17. Nichtlineare Rauschmodellierung von LC Tank VCOs

    NASA Astrophysics Data System (ADS)

    Thiessen, T.; Bremer, J.-K.; Mathis, W.

    2008-05-01

    Im Rahmen dieser Arbeit wird ein alternativer Ansatz zur Phasenrauschoptimierung von LC-Tank Oszillatoren (VCOs) unter Verwendung stochastischer Differentialgleichungen vorgestellt. Zunächst werden die linearen Ansätze von Leeson, Hajimiri und Lee analysiert und bewertet. Danach wird ein Konzept vorgestellt, mit dem man die Rauscheigenschaften von VCOs auf der Grundlage stochastischer Differentialgleichungen und Fokker-Planck-Gleichungen untersuchen kann. Ziel dieser Arbeit ist eine Beschreibung des Phasenrauschens auf der Basis einer nichtlinearen Rauschmodellierung, welche Parameter eines VCOs für eine Optimierung beinhaltet. Es wurde ein Matlab-Tool erstellt und die Funktionalität anhand von Simulationen verifiziert.

  18. Reflexionseigenschaften von Windenergieanlagen im Funkfeld von Funknavigations- und Radarsystemen

    NASA Astrophysics Data System (ADS)

    Sandmann, S.; Divanbeigi, S.; Garbe, H.

    2015-11-01

    Die hier behandelte Untersuchung befasst sich mit den Störungen des elektrischen Feldes einer Doppler Very High Frequency Omnidirectional Radio Range Navigationsanlage (DVOR) in der Gegenwart von Windenergieanlagen (WEA). Hierfür wird die Feldstärke auf 25 konzentrischen Kreisbahnen, sog. Orbit Flights verschiedener Höhen und mit verschiedenen Radien rund um die DVOR-Anlage numerisch simuliert. Insbesondere werden die Einflüsse diverser Parameter der WEA wie deren Anzahl, Position, Rotorwinkel, Turmhöhe und Rotordurchmesser auf die Feldverteilung herausgestellt, sowie die Anwendbarkeit der Simulationsmethode Physical Optics (PO) durch Vergleich der Simulationsergebnisse mit denen der Multi Level Fast Multipol Method (MLFMM) untersucht.

  19. Die Kometenmission Rosetta

    NASA Astrophysics Data System (ADS)

    Krüger, Harald

    2016-11-01

    Die Rosetta-Mission ist ein Meilenstein in der Erforschung der Kometen und ihrer Entstehung. Eine der größten üerraschungen war die unregelmäßge hantelförmige Gestalt des Zielkometen 67P/Tschurjumow-Gerassimenko. Er besteht wahrscheinlich aus zwei Einzelkörpern, die durch ihre Schwerkraft aneinander gehalten werden. Seine Oberfläche ist sehr rau und zeigt eine sehr vielf ältige Morphologie, die auf eine Vielzahl von ablaufenden Prozessen hindeutet. Der Kometenkern ist vermutlich auf Gr ößnskalen von mehr als etwa 10 bis 100 Metern homogen, Inhomogenitäten auf kleineren Skalen k nnten f r seine Aktivä t verantwortlich sein. Diese ist auf kleine Gebiete konzentriert, und auch Oberflächenveränderungen, die sich innerhalb von einigen Tagen bis wenigen Wochen abspielen, sind lokal. Im Kometenmaterial wurde eine Vielzahl an organischen Substanzen gemessen, die zum Teil als Schlüsselmoleküle für die Synthese der Grundbausteine des Lebens gelten, wie wir es kennen.

  20. Beyond The Anticipatory Corpse: Medicine, Power, and the Care of the Dying: A Theoretical and Methodological Intervention into the Sociology of Brain Implant Surgery.

    PubMed

    Hancock, Black Hawk; Morrison, Daniel R

    2016-12-01

    Drawing on and extending the Foucaultian philosophical framework that Jeffrey Bishop develops in his masterful book, The Anticipatory Corpse: Medicine, Power, and the Care of the Dying, we undertake a sociological analysis of the neurological procedure-deep brain stimulation (DBS)-which implants electrodes in the brain, powered by a pacemaker-like device, for the treatment of movement disorders. Following Bishop's work, we carry out this analysis through a two-fold strategy. First, we examine how a multidisciplinary team evaluates candidates for this implant at a major medical center. We present excerpts from an ethnographic study of the "case conference" where disease entities are presented, contested, ratified, and made objects for intervention with this technology. The case conference becomes the key site in the transition from "person-with-illness" to "person-with-brain-implant" as a team of health professionals determines a plan of action by interpreting both statistical and "quality of life" data regarding their patients. Second, this article explores these decision-making processes through Bishop's conceptualization of evidence-based medicine, which relies on statistical approaches as the ultimate authority in knowledge production and medical decisions. We then reflect on Bishop's critique of the social sciences and the methodological, analytical, and substantive ramifications that The Anticipatory Corpse can offer future sociological work.

  1. Energetische Verwertung von Biomasse

    NASA Astrophysics Data System (ADS)

    Zahoransky, Richard; Allelein, Hans-Josef; Bollin, Elmar; Oehler, Helmut; Schelling, Udo

    Etwa 0,1% der Solarenergie wandeln sich durch Photosynthese aus dem Kohlendioxid der Luft in Biomasse um. Die Biomassen sind als Festbrennstoff nutzbar oder zu gasförmigen Brennstoffen weiterverarbeitbar. Zwei Arten von Biomassen sind zu unterscheiden: Anfallende Biomasse

  2. Herausforderungen durch die deutsche Wiedervereinigung

    NASA Astrophysics Data System (ADS)

    Stäglin, Reiner

    Die Wiedervereinigung stellte auch die Statistik vor große Aufgaben. Die als Organ der staatlichen Planung staatsnah orientierte Statistik der DDR musste auf das zur Neutralität und wissenschaftlichen Unabhängigkeit verpflichtete System der Bundesrepublik umgestellt werden. Ebenso verlangten die Universitäten eine Neuorientierung. Die Deutsche Statistische Gesellschaft hat sich vor allem dreier Aufgaben mit großem Engagement, aber auch mit Bedachtsamkeit angenommen: Aufnahme und Integration der Statistiker aus den neuen Bundesländern in die Gesellschaft, Begleitung der Neuausrichtung des Faches Statistik an deren Hochschulen und Sicherung sowie Nutzung von Datenbeständen der ehemaligen DDR.

  3. Mittelwert- und Arbeitstaktsynchrone Simulation von Dieselmotoren

    NASA Astrophysics Data System (ADS)

    Zahn, Sebastian

    Getrieben durch die immer restriktiveren Anforderungen an das Emissions- und Verbrauchsverhalten moderner Verbrennungsmotoren steigt die Komplexität von Motormanagementsystemen mit jeder Modellgeneration an. Damit geht nicht nur eine Zunahme des Softwareumfangs von Steuergeräten sondern zugleich ein deutlicher Anstieg des Applikations-, Vermessungs- und Testaufwandes einher. Zur Effizienzsteigerung des Software- und Funktionsentwicklungsprozesses haben sich daher in der Automobilindustrie sowie in Forschungsinstituten verschiedene modell- und simulationsbasierte Methoden wie die Model-in-the-Loop (MiL) Simulation, die Software-in-the-Loop (SiL) Simulation, das Rapid Control Prototyping (RCP) sowie die Hardware-in-the-Loop (HiL) Simulation etabliert.

  4. Level-Set-Segmentierung von Rattenhirn MRTs

    NASA Astrophysics Data System (ADS)

    Eiben, Björn; Kunz, Dietmar; Pietrzyk, Uwe; Palm, Christoph

    In dieser Arbeit wird die Segmentierung von Gehirngewebe aus Kopfaufnahmen von Ratten mittels Level-Set-Methoden vorgeschlagen. Dazu wird ein zweidimensionaler, kontrastbasierter Ansatz zu einem dreidimensionalen, lokal an die Bildintensität adaptierten Segmentierer erweitert. Es wird gezeigt, dass mit diesem echten 3D-Ansatz die lokalen Bildstrukturen besser berücksichtigt werden können. Insbesondere Magnet-Resonanz-Tomographien (MRTs) mit globalen Helligkeitsgradienten, beispielsweise bedingt durch Oberfiächenspulen, können auf diese Weise zuverlässiger und ohne weitere Vorverarbeitungsschritte segmentiert werden. Die Leistungsfähigkeit des Algorithmus wird experimentell an Hand dreier Rattenhirn-MRTs demonstriert.

  5. Reinraumtechnik für die Medizintechnik

    NASA Astrophysics Data System (ADS)

    Petek, Max; Jungbluth, Martin; Krampe, Erhard

    Die Reinraumtechnik ist heute ein unverzichtbarer Bestandteil bei der Fertigung von Produkten der Life Sciences, den Bereichen Pharma, Lebensmittel, Kosmetik und Medizintechnik. In Anbetracht der langen Historie der Medizintechnik ist sie jedoch eine sehr junge Disziplin. Die Bedeutung von Keimen und die richtige Einschätzung ihrer Größe wurden zwar sehr früh bereits durch Paracelsus erkannt, jedoch wurden daraus noch keine speziellen oder kontinuierlich umgesetzten Hygienevorschriften abgeleitet. Die erste bekannte technische Umsetzung von Hygieneempfehlungen geht auf den Franzosen François Nicolas Appert zurück, der eine aseptische Abfüllmethode für Lebensmittel entwickelte und diese 1810 veröffentlichte [1]. Die erste dokumentierte medizinische Umsetzung stellten Hygienevorschriften für Ärzte dar, die Ignaz Philipp Semmelweis nach 1847 in der Wiener Klinik für Geburtshilfe einführte [2].

  6. Physik gestern und heute Von der Metallstange zum Hochenergielaser

    NASA Astrophysics Data System (ADS)

    Heering, Peter

    2002-05-01

    Im Mai 1752 wurde in Marly bei Paris auf Anregung des amerikanischen Forschers und Politikers Benjamin Franklin erstmals die elektrische Natur des Blitzes nachgewiesen. Damals beschrieb Franklin auch eine technische Vorrichtung, die als Schutz von Gebäuden vor Blitzschlägen dienen sollte: den Blitzableiter. Diese aus heutiger Sicht scheinbar triviale Vorrichtung wurde aber keineswegs unmittelbar akzeptiert. Und bis heute ist die Forschung zum Schutz von Einrichtungen vor Blitzschlägen nicht abgeschlossen.

  7. Die Evolution der Religiosität

    NASA Astrophysics Data System (ADS)

    Voland, Eckart

    Ein konsequent darwinischer Blick auf den Menschen bedeutet, auch im Denken, Fühlen und Handeln biologische Anpassungsgeschichte zu suchen, denn auch die psychischen und mentalen Eigenheiten des Homo sapiens unterliegen der natürlichen Selektion. Lässt sich die religiöse Lebenspraxis von Menschen daher auch aus einer Fitnessperspektive betrachten?

  8. Die kalte Zunge

    NASA Astrophysics Data System (ADS)

    Bartels, Sören; Müller, Rüdiger

    Gefühlte Temperaturen. Ist ein Null Grad Celsius kalter Metallstab eigentlich kälter als ein Holzstab mit der selben Temperatur? Rein physikalisch gesehen natürlich nicht, aber wenn wir beide Stäbe anfassen, kommt uns der Metallstab deutlich kälter vor. Und wer kennt nicht die Szene aus dem Film Dumm und Dümmer in der Harry mit seiner Zunge am Metallrahmen des Skilifts hängen bleibt.Würde das auch passieren, wenn man an einem eiskalten Stück Holz lecken würde? Wohl kaum, doch woran liegt das eigentlich? Unterschiedliche Materialien haben verschiedene Fähigkeiten, Wärme zu übertragen und zu leiten. So transportiert Metall die von der Zunge ausgehende Wärme sehr schnell weiter und verändert seine Temperatur kaum, während die Zunge abkühlt. Holz hingegen leitet Wärme fast gar nicht und daher wird der Teil, der von der Zunge berührt wird, aufgewärmt.

  9. Physikgeschichte Die Anfänge des Physik-Nobelpreises

    NASA Astrophysics Data System (ADS)

    Jacobi, Manfred

    2003-09-01

    Durch Absorption von zwei Laserstrahlen mit unterschiedlichen Wellenlängen können in Halbleitern makroskopische Ströme erzeugt werden. Die Ausbreitungsrichtung der Elektronen und insbesondere die Ausrichtung ihrer Spins lassen sich über die relative Phase der beiden Laserfelder kohärent kontrollieren, wie kürzlich zwei Gruppen an den Universitäten von Marburg und Iowa demonstrierten [1, 2]. Genutzt wird bei diesem Experiment der Effekt der Quanteninterferenz zur Erzeugung von elektrischen Spinströmen.

  10. Dr. Wernher von Braun Laid to Rest

    NASA Technical Reports Server (NTRS)

    1977-01-01

    Dr. Wernher von Braun served as Marshall Space Flight Center's first director from July 1, 1960 until January 27, 1970, when he was appointed NASA Deputy Associate Administrator for Planning. Following World War II, Dr. von Braun and his German colleagues arrived in the United States under Project Paper Clip to continue their rocket development work. In 1950, von Braun and his rocket team were transferred from Ft. Bliss, Texas to Huntsville, Alabama to work for the Army's rocket program at Redstone Arsenal and later, NASA's Marshall Space Flight Center. Under von Braun's leadership, Marshall developed the Saturn V launch vehicle which took Apollo astronauts to the moon. Dr. von Braun died in Alexandria, Va., on June 16, 1977, seven years after his NASA appointment. This photo was taken at the site where he was laid to rest.

  11. Der Physik-Nobelpreis vor 100 Jahren Die Entdeckung des trägen Gases

    NASA Astrophysics Data System (ADS)

    Jacobi, Manfred

    2004-11-01

    Im Jahr 1904 erhielt der britische Physiker Lord Rayleigh (John William Strutt, 1842 bis 1919) den Nobelpreis für seine Untersuchungen über die Dichte von Gasen und die Entdeckung des Edelgases Argon.

  12. SPHERICAL DIE

    DOEpatents

    Livingston, J.P.

    1959-01-27

    A die is presented for pressing powdered materials into a hemispherical shape of uniforin density and wall thickness comprising a fcmale and male die element held in a stationary spaced relation with the space being equivalent to the wall thickness and defining the hemispherical shape, a pressing ring linearly moveable along the male die element, an inlet to fill the space with powdered materials, a guiding system for moving the pressing ring along the male die element so as to press the powdered material and a heating system for heating the male element so that the powdered material is heated while being pressed.

  13. Wissenschaft, die unsere Kultur verändert. Tiefenschichten des Streits um die Evolutionstheorie

    NASA Astrophysics Data System (ADS)

    Patzelt, Werner J.

    Die Evolutionstheorie ist eine der erfolgreichsten wissenschaftlichen Theorien. Sie erlaubt es, unsere Herkunft zu verstehen und riskante Merkmale gerade der menschlichen Spezies zu begreifen. Zugleich ist die Evolutionstheorie eine der umstrittensten Theorien. Das liegt nicht an ihrer empirischen Tragfähigkeit, sondern an ihrem Gegenstand. Sie handelt nämlich nicht nur - wie Hunderte andere wissenschaftliche Theorien - von der "Welt da draußen“, sondern vor allem auch von uns selbst und von unserem Platz in dieser Welt. Den einen gilt sie obendrein als Überwinderin religiösen Aberglaubens, den anderen als neuer Zugang zu Gott und seinem Wirken in der Welt. Ferner sehen die einen in der Evolution eine unbezweifelbare Tatsache gleich der Schwerkraft oder dem Holocaust, die anderen aber eine - noch oder dauerhaft - unbewiesene Hypothese oder gar eine falsche Schöpfungslehre. Und während die meisten Streitfragen solcher Art nach wechselseitig akzeptierten Regeln ‚normaler Wissenschaft‘ geklärt werden, wird bei der Frage nach dem Woher unserer Spezies und Kultur die intellektuelle Zuständigkeit von Wissenschaft mitunter überhaupt bezweifelt. Anscheinend geht es schon um recht tiefe Schichten unserer Kultur und nicht nur der wissenschaftlichen, wenn - wie seit 150 Jahren - um die Evolutionstheorie gestritten wird. Wie sehen diese Schichten aus?

  14. Die Herz-Lungen-Maschine

    NASA Astrophysics Data System (ADS)

    Krane, Markus; Bauernschmitt, Robert; Lange, Rüdiger

    Das Kapitel der modernen Herzchirurgie mit Einsatz der Herz-Lungen-Maschine am Menschen beginnt am 6. Mai 1953, als J. Gibbon bei einer 18-jährigen Patientin einen angeborenen Defekt in der Vorhofscheidewand verschließt [1]. Mit ersten experimentellen Versuchen zur extrakorporalen Zirkulation begann Gibbon bereits in den 30er Jahren des 20. Jahrhunderts. Die Grundlage für die heute gebräuchliche Rollerpumpe schufen Porter und Bradley mit ihrer "rotary pump“, welche sie 1855 zum Patent anmeldeten. Diese Pumpe wurde von DeBakey und Schmidt modifiziert und entspricht im Wesentlichen noch der heute sich im Routinebetrieb befindlichen Rollerpumpe [2].

  15. von Willebrand Disease

    MedlinePlus

    ... from the NHLBI on Twitter. What Is Von Willebrand Disease? Von Willebrand disease (VWD) is a bleeding disorder. ... while hemophilia mainly affects males. Types of von Willebrand Disease The three major types of VWD are called ...

  16. Herstellung von Chitosan und einige Anwendungen

    NASA Astrophysics Data System (ADS)

    Struszczyk, Marcin Henryk

    2001-05-01

    1. Die Deacetylierung von crabshell - Chitosan führte gleichzeitig zu einem drastischen Abfall der mittleren viscosimetrischen Molmasse ( Mv), insbesondere wenn die Temperatur und die Konzentration an NaOH erhöht werden. Diese Parameter beeinflussten jedoch nicht den Grad der Deacetylierung (DD). Wichtig ist jedoch die Quelle des Ausgangsmaterials: Chitin aus Pandalus borealis ist ein guter Rohstoff für die Herstellung von Chitosan mit niedrigem DD und gleichzeitig hoher mittlerer Mv, während Krill-Chitin (Euphausia superba) ein gutes Ausgangsmaterial zur Herstellung von Chitosan mit hohem DD und niedrigem Mv ist. Chitosan, das aus Insekten (Calliphora erythrocephala), unter milden Bedingungen (Temperatur: 100°C, NaOH-Konzentration: 40 %, Zeit: 1-2h ) hergestellt wurde, hatte die gleichen Eigenschaften hinsichtlich DD und Mv wie das aus Krill hergestellte Chitosan. Der Bedarf an Zeit, Energie und NaOH ist für die Herstellung von Insekten-Chitosan geringer als für crabshell-Chitosan vergleichbare Resultaten für DD und Mv. 2. Chitosan wurde durch den Schimmelpilz Aspergillus fumigatus zu Chitooligomeren fermentiert. Die Ausbeute beträgt 25%. Die Chitooligomere wurden mit Hilfe von HPLC und MALDI-TOF-Massenspektrmetrie identifiziert. Die Fermentationsmischung fördert die Immunität von Pflanzen gegen Bakterien und Virusinfektion. Die Zunahme der Immunität schwankt jedoch je nach System Pflanze-Pathogen. Die Fermentation von Chitosan durch Aspergillus fumigatus könnte eine schnelle und billige Methode zur Herstellung von Chitooligomeren mit guter Reinheit und Ausbeute sein. Eine partiell aufgereinigte Fermentationsmischung dieser Art könnte in der Landwirtschaft als Pathogeninhibitor genutzt werden. Durch kontrollierte Fermentation, die Chitooligomere in definierter Zusammensetzung (d.h. definierter Verteilung des Depolymerisationsgrades) liefert, könnte man zu Mischungen kommen, die für die jeweilige Anwendung eine optimale Bioaktivität besitzen. 3

  17. Quantenphysik Interferometrie von C70-Molekülen

    NASA Astrophysics Data System (ADS)

    Ziegler, Thomas

    2002-05-01

    Interferenzversuche mit Neutronen und schweren Atomen stellen kein großes Problem mehr dar, selbst die Welleneigenschaften von C60-und C70-Molekülen wurden bereits nachgewiesen. Allerdings stößt man bei der Realisation immer feinerer Gitter mit Gitterkonstanten von etwa 100 nm im Fall dieser Moleküle auf technische Probleme. Wissenschaftlern der Universität Wien ist es jüngst gelungen, ein so genanntes Talbot-Lau-Interferometer zu realisieren und die Welleneigenschaften von C70 mit einer bislang unerreichten Qualität nachzuweisen [1].

  18. Optoelektronik Infrarotlicht für die Faseroptik

    NASA Astrophysics Data System (ADS)

    Drach, Volker

    2003-07-01

    Die Eigenschaften der kondensierten Materie sind durch die elektronische Bandstruktur bestimmt. Daher sind sie in Raumladungszonen an Oberflächen abhängig von der Ladungsdichte. Ein Team des Forschungszentrums Karlsruhe machte sich nun diesen Effekt zu Nutze und induzierte in metallischen Nanostrukturen durch eine elektrische Spannung reversible Änderungen der makroskopischen Eigenschaften [1].

  19. Die Pugwash Conferences on Science and World Affairs Ein Beispiel für erfolgreiche „Track-II-Diplomacy“ der Naturwissenschaftler im Kalten Krieg

    NASA Astrophysics Data System (ADS)

    Neuneck, Götz

    "Kein Zeitalter der Geschichte ist stärker von den Naturwissenschaften durchdrungen und abhängiger von ihnen als das 20. Jahrhundert" schreibt Eric Hobsbawn im Kapitel "Zauberer und Lehrlinge: Die Naturwissenschaften" seines Buches "Zeitalter der Extreme".

  20. Von Humboldt bis Einstein. Berlin als Weltzentrum der exakten Wissenschaften.

    NASA Astrophysics Data System (ADS)

    Meschkowski, H.

    Contents: 1. Die Anfänge. 2. Die Ära Dirichlet-Jacobi. 3. Der Ausbau der experimentellen Naturwissenschaften. 4. Alexander von Humboldt. 5. Berlin wird "Weltzentrum" der Mathematik. 6. Die Ära Helmholtz. 7. Neue Arbeitsweisen der Astronomie. 8. Chemie: Forschung und Industrie. 9. Max Planck. 10. Ins technische Zeitalter. 11. Zur Mathematik der zwanziger Jahre. 12. Albert Einstein. 13. Fortschritte der Grundlagenforschung. 14. Erwin Schrödinger: Physiker, Philosoph und Poet. 15. Zum Schluß.

  1. Konstruieren von Pkw-Karosserien: Grundlagen, Elemente und Baugruppen, Vorschriftenübersicht, Beispiele mit CATIA V4 und V5

    NASA Astrophysics Data System (ADS)

    Grabner, Jörg; Nothhaft, Richard

    Die Faszination, die vom Auto ausgeht, ist und bleibt ungebrochen. Entsprechend interessant ist es, sich vor dem Hintergrund konventioneller Konstruktionstechniken über die virtuelle Produktentwicklung von Pkw-Karosserien an modernen CAD-Arbeitsplätzen informieren zu können. Die Autoren führen in die Grundlagen ein und zeigen anhand von Beispielen und zahlreichen Abbildungen, wie mit dem System CATIA der Rohbau sowie die Ausstattung innen und au=C3=9Fen konstruiert werden. Darüber hinaus wird das so genannte "Package" an Beispielen beschrieben, also das Management und die Harmonisierung der Anforderungen an die Bauräume (z.

  2. Physik gestern und heute Suprafluidität - Von den Schwierigkeiten einer Messung

    NASA Astrophysics Data System (ADS)

    Sichau, Christian

    2003-03-01

    Der Vater der Tieftemperaturphysik, Heike Kammerlingh Onnes, benötigte zu Beginn des 20. Jahrhunderts für die Verflüssigung von wenigen Litern Heliums noch mehrere Jahre, eine riesige Apparatur und viel Geld. Heute gelingt dies routinemäßig. Die Untersuchung der Materie bei tiefen Temperaturen, insbesondere zur Suprafluidität, bietet viele Überraschungen.

  3. Wer entdeckte die Allgemeine Relativitätstheorie? Prioritätsstreit zwischen Hilbert und Einstein

    NASA Astrophysics Data System (ADS)

    Sommer, Klaus P.

    2005-09-01

    Im November 1915 arbeiteten Albert Einstein und David Hilbert an den Feldgleichungen der Gravitationstheorie. Im Jahre 1997 behaupteten die Wissenschaftshistoriker Corry, Renn und Stachel in einer viel beachteten Arbeit, Hilbert habe die entscheidenden Formeln von Einstein gestohlen. Grundlage ihrer Argumentation war eine wieder gefundene Korrekturfahne von Hilberts entscheidender Arbeit. Die Physikhistorikerin Daniela Wuensch bringt jedoch detaillierte Argumente dafür vor, dass die entscheidende Quelle, nämlich die Korrekturfahne, in neuerer Zeit manipuliert worden ist, um Einsteins Priorität unangetastet zu lassen. Einstein bleibt aber der Entdecker der Allgemeinen Relativitätstheorie.

  4. Die Liberalisierung de Telekommunikationsbranche in Deutschland( The Liberalization of the Telecommunication-Industry in Germany)

    DTIC Science & Technology

    2004-03-01

    anderen europdischen Ldndern - eine dramatische Entwick- lung erlebt: Zahlreiche neue Anbieter von Telekommunikationsdienstleistungen haben den Markt ...AG (DTAG), zweitens die Liberalisierung des Marktzutritts bzw. Offfiung des Marktes , und drittens die Deregulierung. Wdhrend also mit Liberalisierung...die Offnung des Marktes ffir neue Anbieter gemeint ist, wird unter Deregulierung der Abbau staatlicher Vorschriften iiber das Verhalten der Markt

  5. Schichtübergreifende Früherkennung von Verbindungsausfällen in drahtlosen Mesh-Netzwerken

    NASA Astrophysics Data System (ADS)

    Lindhorst, Timo

    Drahtlose Mesh-Netzwerke (WMNs) bilden aufgrund ihrer Selbstorganisation ein flexibles Kommunikationssystem. Bei der Erkennung einzelner Verbindungsausfälle, die bei der Integration mobiler Teilnehmer unvermeidbar sind, ist bei aktuellen Routingprotokollen die Kommunikation jedoch für mehrere Sekunden unterbrochen. In dieser Arbeit wird gezeigt, wie durch Nutzung von Informationen aus der MAC-Schicht ein Ausfall frühzeitig erkannt und dadurch die Anzahl der Paketverluste von mehreren Hundert auf maximal vier reduziert werden kann. Hierdurch wird die Zuverlässigkeit und Verfügbarkeit von WMNs erhöht und ihr Einsatz für Echtzeit-Anwendungen ermöglicht.

  6. Herschel und die Zukunft der Fern-Infrarot-Astronomie

    NASA Astrophysics Data System (ADS)

    Linz, Hendrik

    2015-06-01

    Schon lange ist die beobachtende Astronomie den engen Grenzen des optisch Sichbaren entwachsen und hat fast alle Bereiche des elektromagnetischen Spektrums für sich dienstbar gemacht. Im sogenannten nahen und mittleren Infrarot (Wellenlängen zwischen 1-30 μm) sowie im Millimeter- und Radio-Regime (Wellenlängen zwischen 1 mm und 10 m) ist die Erdatmosphäre relativ gut durchlässig für elektromagnetische Signale oder hat zumindest eine Vielzahl von spektral begrenzten Transmissionsfenstern, die astronomische Beobachtungen zumindest von höheren Bergen aus möglich machen. Allerdings ist das sogenannte Ferne Infrarot (FIR, 30-300 μm Wellenlänge) von der Erde aus fast völlig unzugänglich für astronomische Beobachtungen. Selbst für die besten Beobachtungsplätze der Erde bleibt die atmosphärische Transmission durch die immense Wasserdampf- Absorption auf ein absolutes Minimum beschränkt. Jedoch erlaubt uns das FIR Zugang zu Informationen, die sehr nützlich sind für die astrophysikalische Forschung und komplementär zu anderen Wellenlängen-Bereichen.

  7. Kamera-basierte Erkennung von Geschwindigkeitsbeschränkungen auf deutschen Straen

    NASA Astrophysics Data System (ADS)

    Nienhüser, Dennis; Ziegenmeyer, Marco; Gumpp, Thomas; Scholl, Kay-Ulrich; Zöllner, J. Marius; Dillmann, Rüdiger

    An Fahrerassistenzsysteme im industriellen Einsatz werden hohe Anforderungen bezüglich Zuverlässigkeit und Robustheit gestellt. In dieser Arbeit wird die Kombination robuster Verfahren wie der Hough-Transformation und Support-Vektor-Maschinen zu einem Gesamtsystem zur Erkennung von Geschwindigkeitsbeschränkungen beschrieben. Es setzt eine Farbvideokamera als Sensorik ein. Die Evaluation auf Testdaten bestätigt durch die ermittelte hohe Korrektklassifikationsrate bei gleichzeitig geringer Zahl Fehlalarme die Zuverlässigkeit des Systems.

  8. Theodore von Karman

    NASA Technical Reports Server (NTRS)

    1926-01-01

    Theodore von Karman. NACA: In the eyes of most aeronautical experts, the overall record of Max Munk in aerodynamic research falls short of that achieved by fellow immigrant Theodore von Karman (the short man in the double breasted coat in the middle), shown here visiting Langley in December 1926. People in the photo include Max Munk, aerodynamic researcher; Theodore von Karman; George Lewis, director of research; Henry Reid, engineer in charge; Fred Weick, PRT head; Paul Hemke; Elliott Reid, future Stanford University Professor.

  9. Sputtered protective coatings for die casting dies

    NASA Technical Reports Server (NTRS)

    Mirtich, M. J.; Nieh, C. Y.; Wallace, J. F.

    1981-01-01

    This investigation determined whether selected ion beam sputtered coatings on H-13 die steel would have the potential of improving the thermal fatigue behavior of the steel used as a die in aluminum die casting. The coatings were selected to test candidate insulators and metals capable of providing protection of the die surface. The studies indicate that 1 micrometer thick W and Pt coatings reduced the thermal fatigue more than any other coating tested and are candidates to be used on a die surface to increase die life.

  10. Living with von Willebrand Disease

    MedlinePlus

    ... from the NHLBI on Twitter. Living With von Willebrand Disease If you have von Willebrand disease (VWD), you ... that they get tested too. Pregnancy and von Willebrand Disease Pregnancy can be a challenge for women who ...

  11. Berechnung von Nichtlinearitätsparametern von RF MOS Mischern mittels Volterra-Reihen

    NASA Astrophysics Data System (ADS)

    Susic, A.; Darrat, A. H.; Mathis, W.

    2011-07-01

    Die Nichtlinearität einer Mischerschaltung bezüglich des Informationssignals führt zu unerwünschten Spektralanteilen am Ausgang des Mischers. Da nicht alle Spektralanteile kritisch sind, müssen bei einer Nichtlinearitätsanalyse nur bestimmte Spektralanteile ermittelt werden. In dieser Arbeit wird ein Verfahren zur Bestimmung der Spektralanteile der Zustandsgrößen im Mischer mit Hilfe der Volterra-Reihe gezeigt. Das Verfahren basiert auf die Methode der nichtlinearen Stromquellen. Es wird sowohl auf nicht-schaltende als auch schaltende Mischer angewendet. Hierbei wird der erste als ein zeitinvariantes System mit zwei Eingängen und der zweite als ein periodisch zeitvariantes System mit einem Eingang modelliert. Das Verfahren wird in dem Computeralgebraprogramm MAPLE für den einfach balancierten MOS Mischer implementiert. Es ermöglicht die Herleitung von semi-symbolischen Ausdrücken für die Spektralanteile in Abhängigkeit von den Entwurfsparametern. Die numerischen Ergebnisse des Verfahrens werden gegenüber Simulationen mit SpectreRF verglichen.

  12. Dr. Wernher Von Braun

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Dr. Wernher Von Braun (left) and Fred W. Kelley examine a ST-100 Stellar Instrument Platform in the astrionics lab. Dr. Von Braun, then deputy associate administrator for planning, NASA, was visiting on the anniversary of the establishment of the Marshall Space Flight Center.

  13. Dr. Wernher von Braun

    NASA Technical Reports Server (NTRS)

    2004-01-01

    Dr. von Braun is looking out from a 10th floor window of building 4200 at the Marshall Space Flight Center (MSFC). He was the first Center Director and served as the Director from July 1960 through February 1970. Following World War II, Dr. von Braun and his German colleagues arrived in the United States under the Project Paperclip (American acquisition of German rocket experts) to continue their rocket development work. In 1950, von Braun and his German Rocket Team (also called the Peenemuende Team) were transferred from Ft. Bliss, Texas to Huntsville, Alabama to work for the Army's rocket program at Redstone Arsenal and later, NASA's Marshall Space Flight Center (MSFC). Under Dr. von Braun's leadership, MSFC developed the Saturn V launch vehicle, which placed the first men, two American astronauts, on the Moon. Wernher von Braun's life was dedicated to expanding man's knowledge through the exploration of space.

  14. Kernschmelze Der nachhaltige Einfluss von Nuklearwaffen auf Politik und Wirtschaft

    NASA Astrophysics Data System (ADS)

    Greiner, Bernd

    "Was sollen wir von einer Kultur halten, der die Ethik stets als wesentliches Element des menschlichen Lebens galt, die aber - außer in fachlicher oder spieltheoretischer Terminologie - nicht in der Lage war, über die Möglichkeit zu sprechen, nahezu alle Menschen zu töten?" Der Fragesteller gehört zu den berühmtesten Physikern des 20. Jahrhunderts und zu den nach wie vor Umstrittensten. über ihn wurde in den 1960er Jahren ein international viel beachtetes Theaterstück geschrieben, vor wenigen Jahren gar eine Oper.

  15. Die Gasultrazentrifuge als mediale Projektion des Kalten Krieges

    NASA Astrophysics Data System (ADS)

    Helmbold, Bernd

    Studien der letzten Dekaden nach der Wiedervereinigung von BRD und DDR erweitern die Perspektive der Wissenschaftsgeschichte vom Fokus des Big Science und der technisch-militärisch-industriellen Auseinandersetzung zwischen den zwei Blöcken zu einer globalen Transformation im Konflikt der Supermächte geprägt durch lokale und auch interne Ausformungen.

  16. Datenkompression, Prozessoptimierung, Aerodynamik: Eine Tour Durch die Skalen

    NASA Astrophysics Data System (ADS)

    Dahmen, Wolfgang; Marquardt, Wolfgang

    Enorm gestiegene Rechnerkapazitäten ermutigen zu einer immer genaueren Erschließung komplexer Prozesse in Natur- und Ingenieurwissenschaften durch numerische Simulation. Die Mathematik als Schnittstelle zwischen realer und digitaler Welt liefert einerseits die Grundlagen zur Formulierung notwendigerweise vereinfachter Modelle der Realität. Andererseits bietet sie aber auch die methodischen Grundlagen für den Entwurf effizienter Algorithmen, die aus solchen Modellen quantitative Information gewinnen können. Eine zentrale Herausforderung liegt dabei in der Tatsache, dass reale Prozesse meist durch relevante Anteile auf einer riesigen Spannweite von Längenskalen getrieben werden. Die Entwicklung mathematischer Methoden zur Behandlung von Mehrskaligkeit ist daher von wesentlicher Bedeutung. In diesem Artikel wird dies anhand jüngster Entwicklungen in ganz unterschiedlichen Anwendungsbereichen erklärt und illustriert, auch um deutlich zu machen, wieviele "Fliegen“ man mit einer "mathematischen Klappe“ schlagen kann. Insbesondere werden grundlegende, auf Waveletzerlegung beruhende Prinzipien zunächst im Rahmen der Bildkompression und -kodierung auf weitgehend elementare Weise erklärt. Es wird dann aufgezeigt, dass diese Konzepte in ganz ähnlicher Weise bei der Datenanalyse im Zusammenhang mit verfahrenstechnischen Anwendungen, bei großskaligen Optimierungsproblemen der Prozessindustrie sowie bei komplexen Strömungsproblemen wie in aerodynamischen Anwendungen zum Tragen kommen. Stabile Zerlegungen in Anteile unterschiedlicher Längenskalen eröffnen dabei einen Zugang zu adaptiven Lösungskonzepten, die in der Lage sind, automatisch Rechnerresourcen dort zu plazieren, wo sie zu einer ökonomischen Realisierung der gewünschten Lösungsqualität, etwa in Form von Genauigkeitstoleranzen, benötigt werden.

  17. von Willebrand Disease.

    PubMed

    Swami, Arjun; Kaur, Varinder

    2016-01-01

    von Willebrand disease (vWD) is the most common inherited disorder of hemostasis and comprises a spectrum of heterogeneous subtypes. Significant advances have been made in understanding von Willebrand factor ( vWF) gene mutations, resultant physiologic deficits in the vWF peptide, and their correlation to clinical presentation. Diagnostic tests for this disorder are complex, and interpretation requires a thorough understanding of the underlying pathophysiology by the practicing physician. The objective of this review is to summarize our current understanding of pathophysiology, laboratory investigations, and evolving treatment paradigm of vWD with the availability of recombinant von Willebrand factor.

  18. Matthias Falter und die frühe Halbleitertechnik in der DDR

    NASA Astrophysics Data System (ADS)

    Dittmann, Frank

    Nach einer ganzen Reihe von Vorarbeiten weltweit1 konnten im Dezember 1947 die amerikanischen Physiker Walter H. Brattain, John Bardeen und William Shockley in den Bell Laboratories den Transistoreffekt demonstrieren. Damit legten sie den Grundstein für die Mikroelektronik als Basistechnologie des Informationszeitalters.

  19. Von Willebrand disease

    MedlinePlus

    ... done to diagnose this disease include: Bleeding time Blood typing Factor VIII level Platelet function analysis Platelet count Ristocetin cofactor test Von Willebrand factor specific tests ... invasive procedure. Blood plasma or certain factor VIII preparations may also ...

  20. Stufenweise Integration von eLearning an der Technischen Universität München

    NASA Astrophysics Data System (ADS)

    Pätzold, Sebastian; Graf, Stephan; Gergintchev, Ivan; Pongratz, Hans; Rathmayer, Sabine

    Der vorliegende Beitrag beschreibt als Best Practice Beispiel die stufenweise Integration eines Learning Management Systems (LMS) in die Infrastruktur von Information und Kommunikation (IuK) der Technischen Universität München (TUM). Dabei wird sowohl die Konsolidierung mehrfach angebotener Funktionalitäten und Dienste in den verschiedenen Portalen der Universität als auch die sukzessive Optimierung der Abläufe aufgezeigt. Gleichzeitig wird auf zukünftige weitere Entwicklungen hin zu einer vollständigen Integration der IuK, aber auch auf die Probleme in den unterschiedlichen Stadien der Entwicklung eingegangen.

  1. Dr. Wernher Von Braun

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Dr. Wernher Von Braun (right), Deputy Associate Administrator for planning, National Aeronautics and Space Administration, inspects the mockup of the Saturn Workshop during a visit marking the 10th anniversary of the Marshall Center. Shown with Dr. Von Braun, from left to right, are Karl Heimburg, Director of the astronautics lab; Herman K. Weidner, Director of Science and Engineering, and George Hardy of the Astronautics lab.

  2. Dr. Wernher Von Braun

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Dr. Wernher Von Braun (right), Deputy Associate Administrator for Planning, National Aeronautics and Space Administration, inspects the mockup of the Saturn Workshop during a visit marking the 10th anniversary of the Marshall Center. Shown with Dr. Von Braun, from left to right, are Karl Heimburg, Director of the Astronautics Lab; Herman K. Weidner, Director of Science and Engineering, and George Hardy of the Astronautics Lab.

  3. Untersuchung der Störwirkung von LTE auf SRD Anwendungen bei 868 MHz

    NASA Astrophysics Data System (ADS)

    Welpot, M.; Wunderlich, S.; Gaspard, I.

    2014-11-01

    Moderne Hausautomatisierungssysteme, Alarmanlagen oder auch Funk-Zugangssysteme in Haus und Automobil setzen auf frei nutzbare Frequenzen in ISM/SRD-Bändern. Die rasante Zunahme an privaten und kommerziell genutzten Applikationen im SRD-Band bei 868 MHz und der Ausbau der LTE-Mobilfunknetze im Frequenzbereich unterhalb von 1 GHz ("Digital Dividend") wirft zunehmend die Frage nach der Funkverträglichkeit dieser Systeme untereinander auf. Während die SRD-Funkmodule auf eine geringe Sendeleistung von ~ +14 dBm beschränkt sind (Ralf and Thomas, 2009), beträgt die maximale LTE-Sendeleistung im Uplink nach (ETSI-Norm, 2011) +23 dBm. Zusammen mit der Einführung von LTE im Frequenzbereich unterhalb 1 GHz als DSL-Ersatz vor allem in ländlichen Gebieten, ergibt sich damit als mögliches Störszenario, dass durch die Aussendung des LTE-Endgerätes im Bereich von ca. 850 MHz die SRD-Funkverbindungen bei 868 MHz insbesondere dann gestört werden, wenn die Antennen beider Funksysteme räumlich nahe zueinander angeordnet sind und folglich nur eine geringe zusätzliche Entkopplung der Systeme bieten. In der vorliegenden Arbeit wird das LTE-Störpotential auf SRD-Empfänger praxisnah untersucht.

  4. Cochlear Implants.

    ERIC Educational Resources Information Center

    Clark, Catherine; Scott, Larry

    This brochure explains what a cochlear implant is, lists the types of individuals with deafness who may be helped by a cochlear implant, describes the process of evaluating people for cochlear implants, discusses the surgical process for implanting the aid, traces the path of sound through the cochlear implant to the brain, notes the costs of…

  5. Verbesserte Ausbildung für neue Betriebsleiter und -ingenieure - eine wichtige Investition in die Zukunft

    NASA Astrophysics Data System (ADS)

    Franta, Oliver

    Bedingt durch die Globalisierung und die damit einhergehende Verschärfung des Wettbewerbs befinden sich die Produktionsbetriebe der chemischen Industrie in stetigem Wandel. Für Betriebsleiter und Betriebsingenieure werden damit Fähigkeiten wie Kostenmanagement, Sozial- und Organisationskompetenz, Führungsqualifikationen und unternehmerisches Handeln immer wichtiger. Neben den Anforderungsprofilen bei Neueinstellungen ist dies auch bei der Fortbildung zu berücksichtigen. Das Trainingsprogramm der Evonik Degussa wurde daher durch die Konzeption neuer Seminare und die Anpassung bestehender Weiterbildungsmaßnahmen weiterentwickelt. Neben Vorträgen und Fallbeispielen sind ebenfalls die Durchführung von Planspielen sowie das Kennenlernen eines Produktionsbetriebes einer anderen Organisationseinheit enthalten. Ziel ist es vor allem die unternehmerische Orientierung neuer Betriebsleiter und -ingenieure zu fördern, die Innovationsgeschwindigkeit zu erhöhen und durch Kenntnis und Nutzung bereits anderweitig entwickelter Lösungen und Methoden die Produktivität zu steigern. Die Produktionsmeister werden aufgrund der Bedeutung dieser Funktion für die Führung der Mitarbeiter und bei der Umsetzung von Veränderungsprojekten in das Ausbildungsprogramm einbezogen. Der Erfolg des Trainingsprogramms zeigt sich an den Teilnehmerzahlen und den ausgesprochen positiven Rückmeldungen.

  6. Displaced capillary dies

    DOEpatents

    Kalejs, Juris P.; Chalmers, Bruce; Surek, Thomas

    1984-01-01

    An asymmetrical shaped capillary die made exclusively of graphite is used to grow silicon ribbon which is capable of being made into solar cells that are more efficient than cells produced from ribbon made using a symmetrically shaped die.

  7. Displaced capillary dies

    DOEpatents

    Kalejs, Juris P.; Chalmers, Bruce; Surek, Thomas

    1982-01-01

    An asymmetrical shaped capillary die made exclusively of graphite is used to grow silicon ribbon which is capable of being made into solar cells that are more efficient than cells produced from ribbon made using a symmetrically shaped die.

  8. Effects of inter-implant distance and implant length on the response to frontal traumatic force of two anterior implants in an atrophic mandible: three-dimensional finite element analysis.

    PubMed

    Kan, B; Coskunses, F M; Mutlu, I; Ugur, L; Meral, D G

    2015-07-01

    The aim of this three-dimensional finite element analysis study was to examine the biomechanical behaviour of dental implants and the surrounding bone under traumatic frontal force. Models were created of an edentulous atrophic mandible using cone beam computed tomography data from a patient; two titanium alloy implants (Ti-6Al-4V) were virtually inserted into the anterior of the mandible. Six different variations were modelled to represent differences in implant location (lateral incisor vs. canine placement) and implant length (monocortical, bicortical, and long-bicortical). A static force of 10 MPa was applied frontally to the symphysis region of each model, and the maximum equivalent von Mises strain of bone, maximum von Mises stress of implants, and chromatic force distributions in bone and implants were recorded. In general, when compared to lateral incisor placement, canine placement of implants resulted in greater von Mises stress on implants and greater equivalent von Mises strain on bone. The findings of the present study showed the distribution of traumatic force to be affected more by inter-implant distance than by implant length. The insertion of implants in the lateral incisor area was found to be a better solution than canine area placement in terms of frontal plane trauma and fracture risk.

  9. The Ambiguous Dying Syndrome

    ERIC Educational Resources Information Center

    Bern-Klug, Mercedes

    2004-01-01

    More than one-half of the 2.4 million deaths that will occur in the United States in 2004 will be immediately preceded by a time in which the likelihood of dying can best be described as "ambiguous." Many people die without ever being considered "dying" or "at the end of life." These people may miss out on the…

  10. Jahre Entwicklung der Instandhaltung - von der ausfallorientierten Instandhaltung zum gemeinsamen TPM und RCM

    NASA Astrophysics Data System (ADS)

    Iske, Friedhelm

    Zur Einleitung meines Beitrages möchte ich von einem Gespräch mit einem Mitarbeiter berichten, das ich als junger Vorgesetzter einer Instandhaltungsgruppe 1988 führte. Der engagierte Mitarbeiter feierte damals sein vierzigjähriges Dienstjubiläum und war stolz auf das von ihm Geleistete sowie auf den besonderen Einsatz seiner Altersgruppe, die nach dem Zweiten Weltkrieg das Werk wieder aufgebaut hatte. Auf meine Frage, was denn damals die erste Aufgabe in der Firma war, bekam ich kurz und knapp und mit einer Selbstverständlichkeit die selbstbewusste Antwort: "Unser Pferd füttern und mit dem Pferd die innerbetrieblichen Transporte erledigen“. Als junger, technisch orientierter Vorgesetzter war ich über diese Antwort sehr überrascht. Gedanklich weit entfernt war die Vorstellung, dass in der Vergangenheit Transporte mit einem Pferd erledigt wurden.

  11. Synthese von analogen Filtern auf einer rekonfigurierbaren Hardware-Architektur mittels eines Genetischen Algorithmus

    NASA Astrophysics Data System (ADS)

    Trendelenburg, S.; Becker, J.; Henrici, F.; Manoli, Y.

    2008-05-01

    Rekonfigurierbare Analog-Arrays (FPAAs) sind der Versuch, die Vorteile der aus der digitalen Welt bekannten FPGAs (Flexibilität, Entwurfsgeschwindigkeit) auch für analoge Anwendungen verfügbar zu machen. Aufgrund der Vielfalt der analogen Schaltungstechnik ist die Abbildung von vorgegebenen Schaltungskonzepten auf eine FPAA-Architektur nicht immer einfach lösbar. Diese Arbeit stellt einen neuen Ansatz für die Synthese von Filtern auf einer FPAA-Architektur für zeitkontinuierliche Analogfilter mittels eines Genetischen Algorithmus (GA) vor. Anhand eines Matlab-Modells des FPAA, das eine gute übereinstimmung mit Simulationen des FPAA auf Transistorebene aufweist, wurde gezeigt, dass eine große Vielzahl verschiedener Filterstrukturen auf dieser Architektur dargestellt werden kann. Daraufhin wurde ein Genetischer Algorithmus entwickelt, der es erlaubt, aus einer gegebenen Filterspezifikation Konfigurationsdatensätze zu synthetisieren, die den gewünschten Filter auf die FPAA-Architektur abbilden.

  12. Restaurierung von Seen und Renaturierung von Seeufern

    NASA Astrophysics Data System (ADS)

    Grüneberg, Björn; Ostendorp, Wolfgang; Leßmann, Dieter; Wauer, Gerlinde; Nixdorf, Brigitte

    Süßwasserseen haben als ökosysteme und Lebensraum für Pflanzen und Tiere eine herausragende Bedeutung für die Artenvielfalt auf der Erde und prägen als Landschaftselemente unsere natürliche Umwelt. Seen fungieren als natürliche Stoffsenken, vor allem für Kohlenstoff und Nährstoffe, aber auch als Senken für in ihren Einzugsgebieten emittierte gelöste und feste Schadstoffe. Darüber hinaus ist Wasser eine wichtige Naturressource. Süßwasserseen stellen in den meisten Regionen der Erde lebenswichtige Quellen für die Versorgung mit Trinkwasser und tierischem Eiweiß (Fischfang) dar. Sie dienen als Wasserspeicher für die landwirtschaftliche und industrielle Nutzung. Auch für Erholungsaktivitäten des Menschen kommt ihnen eine große Bedeutung zu.

  13. HIGH PRESSURE DIES

    DOEpatents

    Wilson, W.B.

    1960-05-31

    A press was invented for subjecting specimens of bismuth, urania, yttria, or thoria to high pressures and temperatures. The press comprises die parts enclosing a space in which is placed an electric heater thermally insulated from the die parts so as not to damage them by heat. The die parts comprise two opposed inner frustoconical parts and an outer part having a double frustoconical recess receiving the inner parts. The die space decreases in size as the inner die parts move toward one another against the outer part and the inner parts, though very hard, do not fracture because of the mode of support provided by the outer part.

  14. von Willebrand factor and von Willebrand disease.

    PubMed

    Matsui, Taei; Hamako, Jiharu

    von Willebrand factor (VWF) has two major roles in hemostasis, as a form of molecular glue which functions in platelet plug formation and as a protective transporter for coagulation factor VIII (FVIII). VWF shows a multimeric chain structure composed of 270 kDa subunits containing binding domains for FVIII, platelet and collagens. Biosynthesis, storage, secretion of VWF and the cleavage process by ADAMTS13 (a disintegrin-like and metalloproteinase with thrombospondin type 1 repeats 13) regulating VWF activity have been elucidated. von Willebrand disease (VWD) is an autosomal bleeding disorder, first documented in 1926, caused by quantitative or qualitative deficiency of VWF. The classification and molecular pathogenesis of VWD have been developed during a 90-year period based on clinical laboratory analysis of VWF, and structure-function analysis of mutant VWF with amino acid substitutions (genetic changes). VWF is a unique and very large multifunctional plasma protein, the hemostatic activity of which is dynamically regulated by physiological shear stress in the blood stream.

  15. Nutzergerechte Entwicklung der Mensch-Maschine-Interaktion von Fahrerassistenzsystemen

    NASA Astrophysics Data System (ADS)

    König, Winfried

    Durch langjährige Forschungen bei Kfz-Herstellern, Zulieferfirmen und an Hochschulen sind umfangreiche, aber dennoch lückenhafte Erkenntnisse über das Zusammenspiel zwischen FAS und Nutzer gewonnen worden. In deutschen und internationalen Projekten wie z. B. PROMETHEUS, DRIVE, MOTIV, INVENT, RESPONSE und AKTIV haben sich Kfz-Hersteller, Zulieferfirmen, Hochschulen und weitere staatliche und private Forschungseinrichtungen zusammengefunden, um die vorwettbewerbliche Forschung für derartige Systeme voranzutreiben. Im folgenden Kapitel sollen einige der gewonnenen Kenntnisse dargelegt werden, um die Entwicklung des HMI von FAS zu erleichtern.

  16. Impact of implant diameter and length on stress distribution in osseointegrated implants: A 3D FEA study

    PubMed Central

    Eazhil, R.; Swaminathan, Siva Vadivel; Gunaseelan, Madhan; Kannan, G. Vijay; Alagesan, Chandrapandian

    2016-01-01

    Aims and Objectives: Dimension of dental implant is an important parameter which has a considerable impact on the biomechanical load transfer characters and its prognosis. Excessive stress in the bone–implant interface may result in the failure of the implant. The aim of this study was to evaluate the impact of implant diameter and length on neighboring tissues around the implant. The results of the study will help in developing a scientific methodology to select appropriate implant diameter and length. Materials and Methods: In this study, tapered implants of different diameter and length were numerically analyzed using bone–implant models developed from computed tomography generated images of mandible with osseointegrated implants. The impact of various diameters on stress distribution was examined using implants with a length of 13 mm and diameters of 3.5 mm, 4.3 mm and 5.0 mm. Implants with a diameter of 4.3 mm and lengths of 10 mm, 13 mm, 16 mm was developed to examine the impact of various implant length. All materials were assumed to be linearly elastic and isotropic. Masticatory load was applied in a natural direction, oblique to the occlusal plane. The Statistical Package for the Social Sciences software package was used for statistical analysis. Results: Maximum von Mises stresses were located around the implant neck. It was demonstrated that there was statistically significant decrease in von Mises stress as the implant diameter increased. Conclusion: Within the limitations of this study there was statistically significant decrease in von Mises stress as the implant diameter increased. PMID:28032053

  17. Die Metamorphose des Polypen von Tripedalia cystophora (Cubozoa, Carybdeidae) in die Meduse

    NASA Astrophysics Data System (ADS)

    Werner, B.

    1983-09-01

    The life cycle of the Cubozoa is unique due to the complete metamorphosis of the sessible solitary polyp into one single medusa which starts a pelagic way of life. Contrary to the other metagenetic classes of Scyphozoa and Hydrozoa, the cubozoan polyp terminates its polypoid existence definitely when it metamorphosizes. Generally, the metamorphosis of the cubopolyp is characterized by the transformation of its simple, sac-like multiradial body into the tetraradial structures of the much more complicated medusa. The macroscopic phases of the metamorphosis of Tripedalia cystophora Conant are reviewed, and the internal developmental processes which effect and underlie the transformation are described in detail from new histological investigations. Only the oral pole of the polyp is involved in the active processes of transformation whereas the basal pole follows in a more passive way. The most important process is the invagination of a quadrangular furrow around the hypostome of the polyp by which (a) the subumbrellar room (bell cavity) of the developing medusa is formed, and (b) the four gastric pockets within the wall of the bell are folded off from the polyp's simple stomach. The description of the metamorphosis on the whole and the detailed comparison of the principal developmental processes provide evidence that medusa formation of Cubozoa is different from that of the other metagenetic classes of Scyphozoa and Hydrozoa. The systematic and evolutionary consequences as well as general aspects of medusa formation in the phylum Cnidaria are discussed in detail. In conclusion, the pelagic medusa generation has been “invented” by the ancestors of the recent metagenetic cnidarian classes three times independently.

  18. Dr. Wernher Von Braun

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Shown viewing the Apollo telescope mockup are, from left to right, Charles Donlan, deputy associate administrator for manned space flight; Dr. Wernher Von Braun, Marshall Space Flight Center director; William Horton, astrionics lab; Dr. Thomas Paine, NASA deputy administrator; Warner Kuers, director of the ME lab.

  19. Die Quantenwelt - unbestimmt und nichtlokal?: Interpretation verschränkter Zustände

    NASA Astrophysics Data System (ADS)

    Fink, Helmut

    2004-07-01

    Das aufblühende Gebiet der Quanteninformationsverarbeitung belebt die alte Frage, wie das Phänomen der quantenphysikalischen Verschränktheit zu interpretieren sei. Besonders das berühmte Gedankenexperiment von Einstein, Podolsky und Rosen rückt wieder in das Zentrum der Aufmerksamkeit, seit Laborexperimente an verschränkten Quantensystemen durchgeführt werden, deren Teile räumlich weit von einander entfernt sind. Kann ein Teil eines solchen verschränkten Systems mit Überlichtgeschwindigkeit spüren, dass an einem weit entfernten anderen Teil gemessen wird? Hinter dieser Frage steckt die Vorstellung, es gebe einen nichtlokalen Mechanismus in der Natur. Diese Vorstellung erweist sich jedoch als keineswegs zwingend und sogar als irreführend, wenn man akzeptiert, dass die Werte von Beobachtungsgrößen in Quantenzuständen objektiv unbestimmt sind. Sie entstehen erst dort, wo wirklich gemessen wird.

  20. Aufnahme, Analyse und Visualisierung von Bewegungen nativer Herzklappen in-vitro

    NASA Astrophysics Data System (ADS)

    Weiß, Oliver; Friedl, Sven; Kondruweit, Markus; Wittenberg, Thomas

    Die hohe Zahl an Transplantationen von Herzklappen und viele nötige Re-Operationen machen eine detaillierte Analyse der Strömungen und Klappenbewegungen klinisch interessant. Ein neuer Ansatz ist hierbei der Einsatz von Hochgeschwindigkeitskameras um Bewegungsabl äufe der Herzklappen beobachten und auswerten zu können. Die hohen Datenraten erfordern allerdings eine möglichst automatisierte Analyse und möglichst komprimierte Darstellung des Schwingungsverhaltens. In dieser Arbeit wird ein Ansatz vorgestellt, bei dem Bewegungen nativer Herzklappen in-vitro aufgenommen, analysiert und kompakt visualisiert werden.

  1. Die singulation method

    DOEpatents

    Swiler, Thomas P.; Garcia, Ernest J.; Francis, Kathryn M.

    2013-06-11

    A method is disclosed for singulating die from a semiconductor substrate (e.g. a semiconductor-on-insulator substrate or a bulk silicon substrate) containing an oxide layer (e.g. silicon dioxide or a silicate glass) and one or more semiconductor layers (e.g. monocrystalline or polycrystalline silicon) located above the oxide layer. The method etches trenches through the substrate and through each semiconductor layer about the die being singulated, with the trenches being offset from each other around at least a part of the die so that the oxide layer between the trenches holds the substrate and die together. The trenches can be anisotropically etched using a Deep Reactive Ion Etching (DRIE) process. After the trenches are etched, the oxide layer between the trenches can be etched away with an HF etchant to singulate the die. A release fixture can be located near one side of the substrate to receive the singulated die.

  2. Die singulation method

    DOEpatents

    Swiler, Thomas P [Albuquerque, NM; Garcia, Ernest J [Albuquerque, NM; Francis, Kathryn M [Rio Rancho, NM

    2014-01-07

    A method is disclosed for singulating die from a semiconductor substrate (e.g. a semiconductor-on-insulator substrate or a bulk silicon substrate) containing an oxide layer (e.g. silicon dioxide or a silicate glass) and one or more semiconductor layers (e.g. monocrystalline or polycrystalline silicon) located above the oxide layer. The method etches trenches through the substrate and through each semiconductor layer about the die being singulated, with the trenches being offset from each other around at least a part of the die so that the oxide layer between the trenches holds the substrate and die together. The trenches can be anisotropically etched using a Deep Reactive Ion Etching (DRIE) process. After the trenches are etched, the oxide layer between the trenches can be etched away with a HF etchant to singulate the die. A release fixture can be located near one side of the substrate to receive the singulated die.

  3. Sputtered protective coatings for die casting dies

    NASA Technical Reports Server (NTRS)

    Mirtich, M. J.; Nieh, C.-Y.; Wallace, J. F.

    1981-01-01

    Three experimental research designs investigating candidate materials and processes involved in protective die surface coating procedures by sputter deposition, using ion beam technologies, are discussed. Various pre-test results show that none of the coatings remained completely intact for 15,000 test cycles. The longest lifetime was observed for coatings such as tungsten, platinum, and molybdenum which reduced thermal fatigue, but exhibited oxidation and suppressed crack initiation only as long as the coating did not fracture. Final test results confirmed earlier findings and coatings with Pt and W proved to be the candidate materials to be used on a die surface to increase die life. In the W-coated specimens, which remained intact on the surface after thermal fatigue testing, no oxidation was found under the coating, although a few cracks formed on the surface where the coating broke down. Further research is planned.

  4. Warum Normen für die Instandhaltung?

    NASA Astrophysics Data System (ADS)

    Tschuschke, Werner E.

    Viele kennen Normen wie Konstruktionsnormen, in denen z. B. der Außendurchmesser, die Steigung, der Flankenwinkel und andere Maße eines Gewindes festgelegt sind. Es gibt Prüfnormen aber auch Normen eines Managementsystems wie des Qualitätsmanagements in der DIN-EN-ISO-9000-Familie. Aber warum Normen für die Instandhaltung? Begonnen hat es mit der DIN 31051, die 1985 veröffentlicht wurde. Es war die erste Instandhaltungsnorm weltweit und sie wurde von der Schweiz und Österreich übernommen. In ihr sind Begriffe der Instandhaltung, Grundlagen zum Abnutzungsprozess und Aktivitäten der Instandhaltung beschrieben. Es wurde der Begriff Instandsetzung statt Reparatur publiziert: Nicht mehr Flickschustern sondern einen funktionsfähigen Anlagenzustand möglichst erhalten.

  5. Extrusion die and method

    DOEpatents

    Lipp, G. Daniel

    1994-04-26

    A method and die apparatus for manufacturing a honeycomb body of rhombic cell cross-section by extrusion through an extrusion die of triangular cell discharge slot configuration, the die incorporating feedholes at selected slot intersections only, such that slot segments communicating directly with the feedholes discharge web material and slot segments not so connected do not discharge web material, whereby a rhombic cell cross-section in the extruded body is provided.

  6. The Angry Dying Patient.

    PubMed

    Houston, Robert E.

    1999-02-01

    Over 25 years ago, Kubler-Ross identified anger as a predictable part of the dying process. When the dying patient becomes angry in the clinical setting, all types of communication become strained. Physicians can help the angry dying patient through this difficult time by using 10 rules of engagement. When physicians engage and empathize with these patients, they improve the patient's response to pain and they reduce patient suffering. When physicians educate patients on their normal responses to dying and enlist them in the process of family reconciliation, they can impact the end-of-life experience in a positive way.

  7. Periodisches Hitzdrahtverfahren zur Messung von Wärme- und Temperaturleitfähigkeit von geringen Stoffmengen

    NASA Astrophysics Data System (ADS)

    Griesinger, A.; Spindler, K.; Hahne, E.

    Zusammenfassung Es wird ein Meßverfahren zur gleichzeitigen Bestimmung der Wärme- und der Temperaturleitfähigkeit von geringen Stoffmengen beschrieben. Neben Messungen an hochviskosen Flüssigkeiten eignet sich das Verfahren besonders für Messungen an Pulver-Schüttungen. Das Meßverfahren basiert auf dem transienten Hitzdraht-Verfahren. In einem dünnen Platindraht fließt ein sinusförmiger Wechselstrom, der den Draht periodisch erwärmt. Es entstehen thermische Wellen, die in die umgebende Probe eindringen. Die Amplitude und die Phasenlage der thermischen Wellen in der Probe hängen von der Temperaturleitfähigkeit a und der Wärmeleitfähigkeit λ der Probe ab. Die Temperaturschwingung in der Probe wird mit Hilfe des Platindrahtes gemessen, der gleichzeitig als Widerstandsthermometer eingesetzt wird. Meßwerte von Wasser und Glycerin zeigen eine gute Übereinstimmung mit Literaturwerten. Das Meßverfahren zeichnet sich dadurch aus, daß zur Bestimmung der Wärme- und Temperaturleitfähigkeit nur 13 ml einer Probe benötigt werden. Es werden Meßwerte einer Zeolith-Schüttung unter Wasserstoffbeladung dargestellt. A measuring procedure for the simultaneous determination of the thermal conductivity and thermal diffusivity of small quantities is described. The procedure is suited for high-viscous fluids and for powdery material. The measuring principle is based on the transient hot-wire method. A sinusoidal alternating current flows through a thin platinum wire and heats up the wire periodically. This results in thermal waves, which penetrate into the surrounding sample. The amplitude and the phase shift of the thermal waves depend on the thermal diffusivity ``a'' and the thermal conductivity ``λ'' of the sample. The temperature oscillation in the sample is measured by means of the platinum wire, which is simultaneously applied as a resistance thermometer. The values measured for water and glycerine correspond well to those given in literature. Results of the

  8. Die Soldering in Aluminium Die Casting

    SciTech Connect

    Han, Q.; Kenik, E.A.; Viswanathan, S.

    2000-03-15

    Two types of tests, dipping tests and dip-coating tests were carried out on small steel cylinders using pure aluminum and 380 alloy to investigate the mechanism of die soldering during aluminum die casting. Optical and scanning electron microscopy were used to study the morphology and composition of the phases formed during soldering. A soldering mechanism is postulated based on experimental observations. A soldering critical temperature is postulated at which iron begins to react with aluminum to form an aluminum-rich liquid phase and solid intermetallic compounds. When the temperature at the die surface is higher than this critical temperature, the aluminum-rich phase is liquid and joins the die with the casting during the subsequent solidification. The paper discusses the mechanism of soldering for the case of pure aluminum and 380 alloy casting in a steel mold, the factors that promote soldering, and the strength of the bond formed when soldering occurs. conditions, an aluminum-rich soldering layer may also form over the intermetallic layer. Although a significant amount of research has been conducted on the nature of these intermetallics, little is known about the conditions under which soldering occurs.

  9. Is Dying Young Worse than Dying Old?

    ERIC Educational Resources Information Center

    Jecker, Nancy S.; Schneiderman, Lawrence J.

    1994-01-01

    Notes that, in contemporary Western society, people feel death of small child is greater injustice than death of older adult and experience correspondingly greater sorrow, anger, regret, or bitterness when very young person dies. Contrasts these attitudes with those of ancient Greece and shows relevance that different attitudes toward death have…

  10. Charakterisierung von CMOS RF Blöcken mittels Volterra-Reihen zur Optimierung des Designprozesses

    NASA Astrophysics Data System (ADS)

    Fei, B.; Darrat, A. H.; Mathis, W.

    2009-05-01

    Im Rahmen dieser Arbeit werden die Volterra-Reihen zur Analyse der Nichtlinearität in RF Schaltungen verwendet, um den Designprozess für RF Systeme zu optimieren. Die auf Volterra-Reihen basierende Nichtlinearitätsanalyse wurde in eine Matlab-Toolbox implementiert. Diese Toolbox kann mittels Volterra-Reihen die symbolische Berechnung der Nichtlinearitätsparameter (harmonische Verzerrungen und Intermodulationsverzerrungen) eines RF Blocks für eine gegebene Architektur und Technologie durchführen. Danach können die symbolische Ausdrücke der Nichtlinearitätsparameter in Abhängigkeit von den Architekturparametern und Technologieparametern erhalten werden. Dies ermöglicht die Beschränkung der Wertebereiche der Architekturparameter und die Überprüfung auf die Erfüllung der Nichtlinearitätsspezifikationen für unterschiedliche Kombinationen von Architekturen und Technologien. Somit ist eine Beschränkung der Klassen der Architekturen und Technologien möglich. Die Toolbox wurde zur Verdeutlichung auf einen Low Noise Amplifier (LNA) der Inductive Source Degeneration (ISD) Architektur angewandt. Zur Verifikation wurde diese LNA-Schaltung auch in Cadence SpectreRF Design Tool simuliert.

  11. Beobachtungen von Kometen.

    NASA Astrophysics Data System (ADS)

    Hopf, K.

    1996-12-01

    Checkliste für erfolgreiche Kometenbeobachtung. Kometen gezeichnet. Helligkeitsschätzungen an Kometen. Komet entdeckt - was tun? Die "Neun" hinter dem Komma - oder: Woher kommt der Komet? Kometenschweife. Literatur über Kometen.

  12. Die Deutsche Statistische Gesellschaft in der Weimarer Republik und während der Nazidiktatur

    NASA Astrophysics Data System (ADS)

    Wilke, Jürgen

    Nach anfänglichen Schwierigkeiten durch den 1. Weltkrieg erlangte die Deutsche Statistische Gesellschaft (DStatG) unter dem renommierten Statistiker und Vorsitzenden der DStatG, Friedrich Zahn, durch eine Vielzahl von Aktivitäten hohes Ansehen. Es gab Bestrebungen, Statistiker aus allen Arbeitsfeldern der Statistik in die DStatG zu integrieren, wobei die "Mathematische Statistik" nur zögerlich akzeptiert wurde (Konjunkturforschung, Zeitreihenanalyse). Nach der Machtübernahme 1933 durch Adolf Hitler geriet die DStatG in das Fahrwasser nationalsozialistischer Ideologie und Politik (Führerprinzip, Gleichschaltung des Vereinswesens). Damit war eine personelle Umstrukturierung in der DStatG verbunden. Politisch Missliebige und rassisch Verfolgte mussten die DStatG verlassen (Bernstein, Freudenberg, Gumbel u.a.). Unter den Statistikern gab es alle Abstufungen im Verhalten zum Regime von Ablehnung und zwangsweiser Anpassung über bereitwilliges Mitläufertum bis zu bewusster Täterschaft. Besonders die Bevölkerungsstatistik wurde durch die NS- Rassenpolitik auf lange Sicht diskreditiert. Im Rahmen von Wirtschaftsplanung und Aufrüstung wurden neue zukunftsträchtige statistische Modelle (Grünig, Bramstedt, Leisse) entwickelt.

  13. Dental Implants.

    PubMed

    Zohrabian, Vahe M; Sonick, Michael; Hwang, Debby; Abrahams, James J

    2015-10-01

    Dental implants restore function to near normal in partially or completely edentulous patients. A root-form implant is the most frequently used type of dental implant today. The basis for dental implants is osseointegration, in which osteoblasts grow and directly integrate with the surface of titanium posts surgically embedded into the jaw. Radiologic assessment is critical in the preoperative evaluation of the dental implant patient, as the exact height, width, and contour of the alveolar ridge must be determined. Moreover, the precise locations of the maxillary sinuses and mandibular canals, as well as their relationships to the site of implant surgery must be ascertained. As such, radiologists must be familiar with implant design and surgical placement, as well as augmentation procedures utilized in those patients with insufficient bone in the maxilla and mandible to support dental implants.

  14. Cochlear Implants

    MedlinePlus

    ... NIDCD A cochlear implant is a small, complex electronic device that can help to provide a sense ... are better able to hear, comprehend sound and music, and speak than their peers who receive implants ...

  15. Cochlear implant

    MedlinePlus

    ... antenna. This part of the implant receives the sound, converts the sound into an electrical signal, and sends it to ... implants allow deaf people to receive and process sounds and speech. However, these devices do not restore ...

  16. Micromechanical die attachment surcharge

    DOEpatents

    Filter, William F.; Hohimer, John P.

    2002-01-01

    An attachment structure is disclosed for attaching a die to a supporting substrate without the use of adhesives or solder. The attachment structure, which can be formed by micromachining, functions purely mechanically in utilizing a plurality of shaped pillars (e.g. round, square or polygonal and solid, hollow or slotted) that are formed on one of the die or supporting substrate and which can be urged into contact with various types of mating structures including other pillars, a deformable layer or a plurality of receptacles that are formed on the other of the die or supporting substrate, thereby forming a friction bond that holds the die to the supporting substrate. The attachment structure can further include an alignment structure for precise positioning of the die and supporting substrate to facilitate mounting the die to the supporting substrate. The attachment structure has applications for mounting semiconductor die containing a microelectromechanical (MEM) device, a microsensor or an integrated circuit (IC), and can be used to form a multichip module. The attachment structure is particularly useful for mounting die containing released MEM devices since these devices are fragile and can otherwise be damaged or degraded by adhesive or solder mounting.

  17. Extrusion die and method

    DOEpatents

    Lipp, G. Daniel

    1994-05-03

    A method and die apparatus for manufacturing a honeycomb body of triangular cell cross-section and high cell density, the die having a combination of (i) feedholes feeding slot intersections and (ii) feedholes feeding slot segments not supplied from slot intersections, whereby a reduction in feedhole count is achieved while still retaining good extrusion efficiency and extrudate uniformity.

  18. Right-Wing Extremism in Germany and the Consequences for the Armed Forces (Rechtsextreme orientierungen in deutschland und ihre folgen fuer die bundeswehr)

    DTIC Science & Technology

    2001-06-01

    religi~ iser Gruppen, von denen naturgemai3 nicht alle den Einsatz fremder Streitkrafte in ihrem Staatsgebiet begrtiffen. Ober die Untergrabung von...Miinster/Westfalen. St~Sss, Richard (1994): Forschungs- und Erklarungsansatze - emn Oberblick. In: Kowalski, Wolfgang ; Schr6der, Wolfgang (Hrsg

  19. Nichtrigide Bildregistrierung für die adaptive Strahlentherapie mittels Free Form Deformation

    NASA Astrophysics Data System (ADS)

    Wurst, Gernot; Bendl, Rolf

    Im Rahmen der Adaptiven Strahlentherapie müssen zum Behandlungszeitpunkt Abweichungen der aktuellen Patientengeometrie von den Planungsdaten bekannt sein, damit eine Anpassung des Bestrahlungsplans vorgenommen werden kann. State of the Art ist in diesem Zusammenhang die rigide Registrierung von Planungs- und Kontrolldaten. Hierbei werden jedoch komplexere, nichtrigide Deformationen nicht angemessen berücksichtigt. Daher wurde ein Verfahren entwickelt, das diese komplexen Deformationen durch ein Free Form-Deformationsmodell beschreibt. Die dafür vorzugebenden Translationsvektoren wurden durch Template Matching bestimmt. Es zeigte sich, dass die vorhandenen Deformationen weitgehend erkannt werden. Weiterhin ist das Verfahren aufgrund seines günstigen Laufzeitverhaltens prädestiniert für die Adaptive Strahlentherapie.

  20. Ansätze für eine Bifurkationsanalyse von RF LC-Tank VCOs unter Berücksichtigung nichtlinearer Bauelementegleichungen

    NASA Astrophysics Data System (ADS)

    Zorn, C.; Bremer, J.-K.; Mathis, W.

    2008-05-01

    Es wird ein alternativer Ansatz zum Entwurf von vollintegrierten LC Oszillatoren mit Hilfe der Andronov-Hopf Bifurkationsanalyse unter Einbeziehung eines nichtlinearen Overall-Modells für MOS-Transistoren (EKV-Modell) vorgestellt. Das in dieser Arbeit vorgestellte Verfahren beschreibt die MOS-Kapazität des VCOs über geometrische Gundgrößen, die damit nur als Längen- und Weitenverhältnisse in die Bifurkationsanalyse eingehen. Zur Beschreibung der MOS-Kapazität wurde ein Basic-Charge-Modell, wie es in den Arbeiten von Enz und Vittoz vorgestellt wurde, in Verbindung einer expliziten analytischen Näherung des Oberflächenpotenzials verwendet. Das Verfahren ermöglicht es, als zusätzlichen Freiheitsgrad für den Designer auch die Amplitude zur Optimierung der Bauteilparameter heranzuziehen und vorab eine genauere Abschätzung der Parameter des Varaktors zu erhalten. Zusammengefasst in einer Toolbox führt die Anwendung des Verfahrens auf einen grafischen Optimierungsprozess, mit dessen Hilfe die Parameter analytisch bestimmt werden können. Die verwendete Methode erweitert den von Hajimiri und Ham vorgestellten Entwurfsprozess von LC-Tank VCOs um eine Stabilitätsanalyse, die Berücksichtigung harmonischer höherer Ordnung und die physikalisch exakte Modellierung der Varaktorkapazitäten.

  1. Death, dying, and domination.

    PubMed

    Spindelman, Marc

    2008-06-01

    This Article critiques conventional liberal arguments for the right to die on liberal grounds. It contends that these arguments do not go far enough to recognize and address private, and in particular structural, forms of domination. It presents an alternative that does, which is thus more respectful of true freedom in the context of death and dying, and also more consistent with liberalism. After discussing obstacles to the achievement of a right to die that encompasses freedom from both public and private domination, the Article closes with a significant reform project within bioethics that might help bring it about.

  2. STF Optimierung von single-bit CT ΣΔ Modulatoren basierend auf skalierten Filterkoeffizienten

    NASA Astrophysics Data System (ADS)

    Widemann, C.; Zorn, C.; Brückner, T.; Ortmanns, M.; Mathis, W.

    2012-09-01

    Die vorliegende Arbeit beschäftigt sich mit dem Signalübertragungsverhalten von single-bit continuous-time (CT) ΣΔ Modulatoren. Dabei liegt der Fokus der Untersuchung auf dem Peaking der Signaltransferfunktion (STF). Dieser Effekt kann die Performance und die Stabilität des Gesamtsystems negativ beeinflussen, da bei auftretendem STF-Peaking Signale außerhalb des Signalbands verstärkt werden. In dieser Arbeit wird ein neuer Ansatz zur Reduktion des Peakings vorgestellt, der auf der Optimierung der Systemdynamik basiert. Dabei werden die Filterkoeffizienten des Modulators systematisch angepasst. Anhand eines Beispielsystems wird gezeigt, dass der Ansatz genutzt werden kann, um das Übertragungsverhalten des Modulators abhängig vom Ausgangssystem zu verändern. So kann entweder die Systemsperformance verbessert werden, ohne Peaking in der STF zu erzeugen, oder das STF-Peaking reduziert werden, ohne die Systemperformance stark zu beeinflussen.

  3. Untersuchung der Richtwirkung der Einkopplung von ebenen Wellen in eine Leitung

    NASA Astrophysics Data System (ADS)

    Magdowski, M.; Vick, R.

    2013-07-01

    Elektrische Leitungen und Kabel stellen häufig die Haupteinfallstore für elektromagnetische Felder in die daran angeschlossenen Geräte und Systeme dar. Für die Einkopplung einer ebenen Welle kann der in eine Leitung eingekoppelte Strom unter bestimmten Voraussetzungen mit Hilfe der Leitungstheorie sehr effizient bestimmt werden. Er hängt dabei von den Abmessungen der Leitung, den Leitungsabschlüssen sowie der Amplitude, der Wellenlänge und der Einfallsrichtung der ebenen Welle ab. In dieser Arbeit wird die Abhängigkeit der Einkopplung von der Einfallsrichtung näher untersucht. Dazu werden Richtdiagramme der Einkopplung berechnet, dargestellt und hinsichtlich der mittleren und maximalen Einkopplung über alle Einfallsrichtungen und Polarisationen ausgewertet. Die Ergebnisse werden genutzt, um die maximale Direktivität der Einkopplung in eine Leitung zu bestimmen. Fasst man die Einkopplung externer Felder in eine Leitung als einen Störfestigkeitstest auf, so kann die maximale Direktivität benutzt werden, um einen Vergleich zwischen unterschiedlichen Messumgebungen wie Absorberhallen und Modenverwirbelungskammern herzustellen.

  4. Anwendung einer Switched-System Modellierung zur Stabilitätsanalyse von zeitkontinuierlichen singlebit ΣΔ-Wandlern

    NASA Astrophysics Data System (ADS)

    Stegemann, S.; Zorn, C.; Brückner, T.; Ortmanns, M.; Mathis, W.

    2011-08-01

    Im Hinblick auf die Optimierung von zeitkontinuierlichen ΣΔ-Wandlern ist ein genaues Verständnis der dynamischen Eigenschaften des Systems von essentieller Bedeutung. In dieser Arbeit wird der ΣΔ-Modulator dafür in die Klasse der Mixed-Signal Systeme eingeordnet und als Übertragungssystem mit geschalteter Rückkopplung betrachtet. Mit diesem Switched-System-Modell können unter Zuhilfenahme einer geeigneten Zustandsraumdarstellung die Signalamplituden der internen Integratoren sowie die Maximalamplitude am Quantisierereingang bestimmt werden. Unter Verwendung einer Worst-Case Analyse ist es damit möglich, Aussagen über den Aussteuerbereich der Integratoren sowie der maximal stabilen Eingangsamplitude zu treffen. Die Vorgehensweise wird anhand eines Beispielmodulators dargestellt.

  5. Von Karman swirling flows

    NASA Astrophysics Data System (ADS)

    Zandbergen, P. J.; Dijkstra, D.

    A development history is presented for research on the problem of swirling flow infinite disks from its formulation by von Karman in 1921 through the treatments of Batchelor (1951) and Stewartson (1953) to the present, with a view to both its one-disk and two-disk forms. Attention is given to the stability of the stationary solutions for these problems, and to the case where the radii of the disks are finite. The question as to the extent to which the Karman swirling flow occurs in a finite radial geometry is noted to be of fundamental importance.

  6. Dr. Wernher Von Braun

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Dr. Thomas Paine, Deputy Administrator of the National Aeronautics and Space Administration, examines an ordinary man's shoe outfitted for use in the Saturn I workshop. Pictured from the left in the Saturn I workshop mockup are William Brooksbank, propulsion and vehicle engineering laboratory; Dr. Paine; Dr. Wernher Von Braun, Marshall Center director; Colonel Clare F. Farley, Executive Officer in the Office Of The Administrator; and Charles J. Donlan, Deputy Associate Administrator for Manned Space Flight, Technical. the shoe Dr. Paine is holding has a unique fastener built into the sole to allow an astronaut to move about on the workshop floor and to remain in one position if he desires.

  7. von Willebrand Disease (For Parents)

    MedlinePlus

    ... problems because the levels or functioning of these blood components needed for clotting are abnormal. continue Types of von Willebrand Disease As with many conditions, there are various forms ... of von Willebrand factor in the blood is reduced; the level of factor VIII also ...

  8. Three-dimensional finite element analysis of platform switched implant

    PubMed Central

    2017-01-01

    PURPOSE The purpose of this study was to analyze the influence of the platform switching concept on an implant system and peri-implant bone using three-dimensional finite element analysis. MATERIALS AND METHODS Two three-dimensional finite element models for wide platform and platform switching were created. In the wide platform model, a wide platform abutment was connected to a wide platform implant. In the platform switching model, the wide platform abutment of the wide platform model was replaced by a regular platform abutment. A contact condition was set between the implant components. A vertical load of 300 N was applied to the crown. The maximum von Mises stress values and displacements of the two models were compared to analyze the biomechanical behavior of the models. RESULTS In the two models, the stress was mainly concentrated at the bottom of the abutment and the top surface of the implant in both models. However, the von Mises stress values were much higher in the platform switching model in most of the components, except for the bone. The highest von Mises values and stress distribution pattern of the bone were similar in the two models. The components of the platform switching model showed greater displacement than those of the wide platform model. CONCLUSION Due to the stress concentration generated in the implant and the prosthodontic components of the platform switched implant, the mechanical complications might occur when platform switching concept is used. PMID:28243389

  9. Implantable Microimagers

    PubMed Central

    Ng, David C.; Tokuda, Takashi; Shiosaka, Sadao; Tano, Yasuo; Ohta, Jun

    2008-01-01

    Implantable devices such as cardiac pacemakers, drug-delivery systems, and defibrillators have had a tremendous impact on the quality of live for many disabled people. To date, many devices have been developed for implantation into various parts of the human body. In this paper, we focus on devices implanted in the head. In particular, we describe the technologies necessary to create implantable microimagers. Design, fabrication, and implementation issues are discussed vis-à-vis two examples of implantable microimagers; the retinal prosthesis and in vivo neuro-microimager. Testing of these devices in animals verify the use of the microimagers in the implanted state. We believe that further advancement of these devices will lead to the development of a new method for medical and scientific applications. PMID:27879873

  10. Analyse unterschiedlicher Modellierungsvarianten des "Direct Power Injection" Verfahrens für die EMV Charakterisierung integrierter Schaltungen

    NASA Astrophysics Data System (ADS)

    Stürmer, U.; Ritzmann, S.; Jovic, O.; Wilkening, W.

    2009-05-01

    Dieser Beitrag analysiert zwei Ansätze zur Modellierung eines Teststandes zur Charakterisierung von integrierten Schaltungen mittels Direct Power Injection (DPI) auf einem Wafer. Die erste Variante ist zur Analyse bereits vorliegender integrierter Schaltungen nutzbar. Sie benötigt gemessene S-Parameterdaten, mit denen die an einem realen Messobjekt anliegenden Störspannungen frequenzabhängig bestimmt werden können. Die zweite Variante ist bereits anwendbar, bevor Silizium gefertigt worden ist. Sie modelliert einen Netzwerkanalysatorkanal der aus einer Signalquelle, einem Leistungsmesser und einem Verstärker mit nachgeschaltetem Richtkoppler und Entkoppelnetzwerken besteht. Zunächst werden die oben genannten verschiedenen Varianten der DPI-Streckenmodellierung dargestellt. Sie werden miteinander und anhand von Messdaten einer einfachen Teststruktur verglichen. Die Teststruktur besteht aus einem MOS-Transistor mit Arbeitswiderstand. Der Beitrag diskutiert Vor- und Nachteile der Varianten einschließlich Modellierungsaufwand und Simulationsgeschwindigkeit.

  11. Endodontic implants

    PubMed Central

    Yadav, Rakesh K.; Tikku, A. P.; Chandra, Anil; Wadhwani, K. K.; Ashutosh kr; Singh, Mayank

    2014-01-01

    Endodontic implants were introduced back in 1960. Endodontic implants enjoyed few successes and many failures. Various reasons for failures include improper case selection, improper use of materials and sealers and poor preparation for implants. Proper case selection had given remarkable long-term success. Two different cases are being presented here, which have been treated successfully with endodontic implants and mineral trioxide aggregate Fillapex (Andreaus, Brazil), an MTA based sealer. We suggest that carefully selected cases can give a higher success rate and this method should be considered as one of the treatment modalities. PMID:25298723

  12. Breast Implants

    MedlinePlus

    ... sale in the United States: saline-filled and silicone gel-filled. Both types have a silicone outer shell. They vary in size, shell thickness, ... implant them. Provide information on saline-filled and silicone gel-filled breast implants, including data supporting a ...

  13. John von Neumann Birthday Centennial

    SciTech Connect

    Grcar, Joseph F.

    2004-11-12

    In celebration of John von Neumann's 100th birthday, a series of four lectures were presented on the evening of February 10, 2003 during the SIAM Conference on Computational Science and Engineering in San Diego. The venue was appropriate because von Neumann spent much of the later part of his life, in the 1950's, as an unofficial ambassador for computational science. He was then the only senior American scientist who had experience with the new computers (digital, electronic, and programmable) and a vision of their future importance. No doubt he would have relished the chance to attend a meeting such as this. The first speaker, William Aspray, described the ''interesting times'' during which computers were invented. His remarks were based on his history [1] of this period in von Neumann's life. We were honored to have John von Neumann's daughter, Marina von Neumann-Whitman, as our second speaker. Other accounts of von Neumann's life can be found in books by two of his colleagues [2] and [3]. Our third speaker, Peter Lax, provided both mathematical and international perspectives on John von Neumann's career. Finally, Pete Stewart spoke about von Neumann's numerical error analysis [4] in the context of later work; this talk did not lend itself to transcription, but readers may consult the historical notes in [5]. Our thanks to all the speakers for a remarkable evening. We are grateful to the DOE Applied Mathematical Sciences (AMS) program for partially supporting these lectures. Thanks are also due to SIAM and William Kolata, to our emcee, Gene Golub, to Paul Saylor for recording and editing, and to Barbara Lytle for the transcriptions. More about von Neumann's work can be learned from the recent American Mathematical Society proceedings [6].

  14. von Karman Vortices

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Each of these swirling clouds is the result of a meteorological phenomenon known as a von Karman vortex. These vortices appeared over Alexander Selkirk Island in the southern Pacific Ocean. Rising precipitously from the surrounding waters, the island's highest point is nearly a mile (1.6 km) above sea level. As wind-driven clouds encounter this obstacle, they flow around it to form large, spinning eddies. This image was acquired by Landsat 7's Enhanced Thematic Mapper plus (ETM+) sensor on September 15, 1999. This is a false-color composite image made using shortwave infrared, infrared, and near-infrared wavelengths. Image provided by the USGS EROS Data Center Satellite Systems Branch.

  15. Von Hippel's disease in association with von Recklinghausen's neurofibromatosis.

    PubMed Central

    Thomas, J V; Schwartz, P L; Gragoudas, E S

    1978-01-01

    Ten members of a large family who showed manifestations of either von Hippel-Lindau disease or von Recklinghausen's neurofibromatosis were examined. Three of 10 members were found to have retinal angiomas which had not been present on fundus examination 3 years previously. These angiomas were associated with ocular and systemic signs of neurofibromatosis. These cases show overlapping manifestations of different phakomatoses and provide support for the concept of a common aetiology for these diseases. Images PMID:101230

  16. Modellbasierte Segmentierung von differenzierten Lymphknoten in CT-Daten

    NASA Astrophysics Data System (ADS)

    Dornheim, Lars; Dornheim, Jana

    Für die computerbasierte Diagnoseunterstützung bei Tumorerkrankungen ist Wissen über Lage, Ausdehnung und Art der Lymphknoten für die TNM-Klassifikation nötig. Für die computergestütze Planung nachfolgender Eingriffe wie der Hals-Lymphknoten-Ausräumung, ist dieses Wissen ebenfalls von Bedeutung. Deshalb ist ein effizientes und exaktes Segmentierungsverfahren für Lymphknoten in CT-Datensätzen erforderlich, das besonders auch mit pathologisch veränderten Lymphknoten zurechtkommt. Basierend auf früheren Arbeiten präsentieren wir in dieser Arbeit ein deutlich weiterentwickeltes, modellbasiertes Segmentierungsverfahren für Lymphknoten in CT-Datensätzen, mit dem nun besonders auch vergrößerte sowie nekrotische Lymphknoten adressiert werden. Unser Verfahren wurde an 21 Lymphknoten aus 5 CT-Datensätzen getestet, darunter mehrere vergrößerte und nekrotische. Die Ergebnisse liegen im Bereich der Inter-Personen-Varianz und verbessern die Ergebnisse früherer Arbeiten noch einmal spürbar.

  17. Zur ethischen Dimension von Renaturierungsökologie und Ökosystemrenaturierung

    NASA Astrophysics Data System (ADS)

    Ott, Konrad

    Die wissenschaftlich angeleitete Ökosystemrena-turierung kann mittlerweile als eine etablierte Praxis im Bereich des Naturschutzes gelten. Diese Praxis bezieht sich notwendigerweise auf Ziele und Werte und weist damit auch eine naturethische Dimension auf. Daher hat diese Praxis die Aufmerksamkeit auch von Sozialwissenschaftlern und Ethikern auf sich gezogen. Dieses Kapitel geht der Frage nach, wie sich die naturethische Dimension der Ökosystemrenaturierung analysieren und inhaltlich bestimmen lässt. Hierzu erweist sich auch die Auseinandersetzung mit Philosophen als hilfreich, die der Ökosystemrenaturierung ein technizistisches Naturverständnis vorgeworfen haben. Am Ende des Kapitels wird ein in sich gestuftes mögliches naturethisches Selbstverständnis der Ökosystemrenaturierung diskutiert, das den an dieser Praxis Beteiligten Freiheitsgrade der Positionierung belässt.

  18. Vorausschauend Planen, Gezielt Handeln — Über Die Regelung Und Steuerung Technischer Prozesse

    NASA Astrophysics Data System (ADS)

    Grüne, Lars; Sager, Sebastian; Allgöwer, Frank; Bock, Hans Georg; Diehl, Moritz

    Seit Beginn der industriellen Revolution nimmt die Steuerungs- und Regelungstechnik eine Schlüsselstellung in vielen technischen Bereichen ein. James Watts Fliehkraftregler für Dampfmaschinen ist eines der frühen Beispiele eines extrem erfolgreichen Reglerkonzepts, von dem Ende der 1860er Jahre geschätzte 75000 Exemplare allein in England im Einsatz waren [2, S. 24]. Etwa um diese Zeit begannen Ingenieure, motiviert durch die immer höhere Komplexität der zu regelnden Maschinen, sich systematisch mit theoretischen Grundlagen der Regelung zu beschäftigen. Dies führte unausweichlich zu der Einsicht, dass das dynamische Verhalten der geregelten Systeme nur mit Hilfe der Mathematikverstanden und weiterentwickelt werden konnte, oder wie Werner von Siemens, ein weiterer technischer Pionier in diesem Bereich es formulierte: "Ohne Mathematik tappt man doch immer im Dunkeln.“

  19. When a Baby Dies.

    ERIC Educational Resources Information Center

    Church, Martha Jo; And Others

    Written especially for grieving mothers whose babies have died, this booklet offers an overview of stages and experiences through which bereaved parents commonly pass. Specifically, the text is intended to give comfort to bereaved parents, offer insight into the grieving process, and provide thoughts on leave-taking ceremonies. The first section…

  20. When Somebody Dies

    MedlinePlus

    ... to have fun with. That absence leaves a big hole in our lives. Maybe you had a pet that died . Remember the first few times you walked into the house after your dog or cat was gone? It was strange not to have ...

  1. Die Kosmologie der Griechen.

    NASA Astrophysics Data System (ADS)

    Mittelstraß, J.

    Contents: 1. Mythische Eier. 2. Thales-Welten. 3. "Alles ist voller Götter". 4. Griechische Astronomie. 5. "Rettung der Phänomene". 6. Aristotelische Kosmololgie. 7. Aristoteles-Welt und Platon-Welt. 8. Noch einmal: die Göttlichkeit der Welt. 9. Griechischer Idealismus.

  2. When Somebody Dies

    MedlinePlus

    ... A A What's in this article? When — and How — Does It Happen? Where Do Dead People Go? What Does Grieving Mean? What About Me? If I'm Going to Die Someday, What Should I Do Now? en español ...

  3. von Braun and German Publisher

    NASA Technical Reports Server (NTRS)

    1969-01-01

    In this photograph, Guenter Ogger of Capitol Magazine, West Germany, greets Marshall Space Flight Center Director, Dr. Wernher von Braun. Mr. Ogger interviewed the famous rocket scientist for his magazine.

  4. Networking as a Seismograph for Social Development. A Contribution to the Function Expansion of Networks Using the Example of Health Promotion of the Socially Disadvantaged (Netzwerkbildung als Seismograph gesellschaftlicher Entwicklungen: Ein Beitrag zur Funktionserweiterung von Netzwerken am Beispiel der Gesundheitsfoerderung von sozial Benachteiligten)

    DTIC Science & Technology

    2008-03-01

    vollzieht sich in den letzten Jahren Ober eine Vielzahl von Netzwerken, uber die sich unterschiedlichste Akteure miteinander verknQ~pft haben. In...indirekt, politische 2 Akteure zu adressieren und bisherige Handlungsdefizite der Gesundheitsf6rderung bei sozial Benachteiligten auch uber neue...klassischen Sinne der Korporatismusanalyse impliziert, sondern gar eine Form der Einwandvorwegnahme darsteilt. Auf der Grundlage der durch die bislang uber

  5. Von Karman and JATO Team

    NASA Technical Reports Server (NTRS)

    1940-01-01

    Dr. Theodore von Karman (black coat) sketches out a plan on the wing of an airplane as his JATO engineering team looks on. From left to right: Dr. Clark B. Millikan, Dr.Martin Summerfield, Dr. Theodore von Karman, Dr. Frank J. Malina and pilot, Capt. Homer Boushey. Captain Boushey would become the first American to pilot an airplane that used JATO (Jet Assisted Take-Off) solid propellent rockets.

  6. Histrelin Implant

    MedlinePlus

    ... implant (Supprelin LA) is used to treat central precocious puberty (CPP; a condition causing children to enter puberty too soon, resulting in faster than normal bone growth and development of sexual characteristics) in girls ...

  7. Penile Implants

    MedlinePlus

    ... placed inside the penis to allow men with erectile dysfunction (ED) to get an erection. Penile implants are ... complications and follow-up care. For most men, erectile dysfunction can be successfully treated with medications or use ...

  8. Extra-aortic implantable counterpulsation pump in chronic heart failure.

    PubMed

    Mitnovetski, Sergei; Almeida, Aubrey A; Barr, Althea; Peters, William S; Milsom, F Paget; Ho, Betty; Smith, Julian A

    2008-06-01

    Extra-aortic counterpulsation for the management of chronic heart failure is a novel approach. We report the use of an extra-aortic implantable counterpulsation pump in the management of a 73-year-old patient with severe heart failure refractory to medical therapy. The implantable counterpulsation pump prolonged his life and greatly improved its quality. The patient lived almost 7 months after the implantation of the device and died of septic complications secondary to gas line infection.

  9. Spontaneous haemothorax associated with von Recklinghausen's disease: review of occurrence in Japan

    PubMed Central

    Miura, H.; Taira, O.; Uchida, O.; Usuda, J.; Hirai, S.; Kato, H.

    1997-01-01

    The case history is presented of a 61 year old man with von Recklinghausen's disease who developed a spontaneous haemothorax. In spite of being asymptomatic for five days after drainage, he died as a result of fatal sudden re-bleeding. The post mortem examination showed dissection and rupture of the left subclavian artery. Microscopically, disarrangement of smooth muscle and decrease of elastic fibre was observed in the ruptured artery. Haemothorax in patients with von Recklinghausen's disease may require thoracotomy, even if the condition of the patient appears to be stable. 


 PMID:9227730

  10. Cochlear implants.

    PubMed

    Connell, Sarah S; Balkany, Thomas J

    2006-08-01

    Cochlear implants are cost-effective auditory prostheses that safely provide a high-quality sensation of hearing to adults who are severely or profoundly deaf. In the past 5 years, progress has been made in hardware and software design, candidate selection, surgical techniques, device programming, education and rehabilitation,and, most importantly, outcomes. Cochlear implantation in the elderly is well tolerated and provides marked improvement in auditory performance and psychosocial functioning.

  11. Modeling the Mechanical Performance of Die Casting Dies

    SciTech Connect

    R. Allen Miller

    2004-02-27

    The following report covers work performed at Ohio State on modeling the mechanical performance of dies. The focus of the project was development and particularly verification of finite element techniques used to model and predict displacements and stresses in die casting dies. The work entails a major case study performed with and industrial partner on a production die and laboratory experiments performed at Ohio State.

  12. Contraceptive implants.

    PubMed

    McDonald-Mosley, Raegan; Burke, Anne E

    2010-03-01

    Implantable contraception has been extensively used worldwide. Implants are one of the most effective and reversible methods of contraception available. These devices may be particularly appropriate for certain populations of women, including women who cannot use estrogen-containing contraception. Implants are safe for use by women with many chronic medical problems. The newest implant, Implanon (Organon International, Oss, The Netherlands), is the only device currently available in the United States and was approved in 2006. It is registered for 3 years of pregnancy prevention. Contraceptive implants have failure rates similar to tubal ligation, and yet they are readily reversible with a return to fertility within days of removal. Moreover, these contraceptive devices can be safely placed in the immediate postpartum period, ensuring good contraceptive coverage for women who may be at risk for an unintended pregnancy. Irregular bleeding is a common side effect for all progestin-only contraceptive implants. Preinsertion counseling should address possible side effects, and treatment may be offered to women who experience prolonged or frequent bleeding.

  13. Von Willebrand factor processing.

    PubMed

    Brehm, Maria A

    2017-01-31

    Von Willebrand factor (VWF) is a multimeric glycoprotein essential for primary haemostasis that is produced only in endothelial cells and megakaryocytes. Key to VWF's function in recruitment of platelets to the site of vascular injury is its multimeric structure. The individual steps of VWF multimer biosynthesis rely on distinct posttranslational modifications at specific pH conditions, which are realized by spatial separation of the involved processes to different cell organelles. Production of multimers starts with translocation and modification of the VWF prepropolypeptide in the endoplasmic reticulum to produce dimers primed for glycosylation. In the Golgi apparatus they are further processed to multimers that carry more than 300 complex glycan structures functionalized by sialylation, sulfation and blood group determinants. Of special importance is the sequential formation of disulfide bonds with different functions in structural support of VWF multimers, which are packaged, stored and further processed after secretion. Here, all these processes are being reviewed in detail including background information on the occurring biochemical reactions.

  14. Richard von Volkmann

    PubMed Central

    Willy, Christian; Schneider, Peter; Engelhardt, Michael; Hargens, Alan R.

    2008-01-01

    Richard von Volkmann (1830–1889), one of the most important surgeons of the 19th century, is regarded as one of the fathers of orthopaedic surgery. He was a contemporary of Langenbeck, Esmarch, Lister, Billroth, Kocher, and Trendelenburg. He was head of the Department of Surgery at the University of Halle, Germany (1867–1889). His popularity attracted doctors and patients from all over the world. He was the lead physician for the German military during two wars. From this experience, he compared the mortality of civilian and war injuries and investigated the general poor hygienic conditions in civilian hospitals. This led him to introduce the “antiseptic technique” to Germany that was developed by Lister. His powers of observation and creativity led him to findings and achievements that to this day bear his name: Volkmann’s contracture and the Hueter-Volkmann law. Additionally, he was a gifted writer; he published not only scientific literature but also books of children’s fairy tales and poems under the pen name of Richard Leander, assuring him a permanent place in the world of literature as well as orthopaedics. PMID:18196438

  15. Heated die facilitates tungsten forming

    NASA Technical Reports Server (NTRS)

    Chattin, J. H.; Haystrick, J. E.; Laughlin, J. C.; Leidy, R. A.

    1966-01-01

    Tungsten forming in a press brake employs a bottom die assembly with a heating manifold between two water-cooled die sections. The manifold has hydrogen-oxygen burners spaced along its length for even heat during forming.

  16. Designing a Die for Hydroforming

    NASA Astrophysics Data System (ADS)

    Vasile, Radu

    2016-12-01

    Designing a die is in every application field an intensive process of bringing together know how from design, testing and every-day use from previous dies with the new application requirements. Contribution deals with a knowledge oriented, modular and feature integrated computer aided design system for die development. This paper describes the concepts behind designing a hydroforming die for sheet metal forming, with easy application-use in small workshops for testing hydroforming capabilities of different materials.

  17. Dying with dignity.

    PubMed

    Madan, T N

    1992-08-01

    Death is a theme of central importance in all cultures, but the manner in which it is interpreted varies from society to society. Even so, traditional cultures, including Christian, Hindu and Jain religious traditions, exhibited a positive attitude to death and did not look upon it in a dualistic framework of good vs bad, or desirable vs undesirable. Nor was pessimism the dominant mood in their thinking about death itself. A fundamental paradigm shift occurred in the West in the eighteenth century when death was desacralized and transformed into a secular event amenable to human manipulation. From those early beginnings, dying and death have been thoroughly medicalized and brought under the purview of high technology in the twentieth century. Once death is seen as a problem for professional management, the hospital displaces the home, and specialists with different kinds and degrees of expertise take over from the family. Everyday speech and the religious idiom yield place to medical jargon. The subject (an ageing, sick or dying person) becomes the object of this make-believe yet real world. As the object of others' professional control, he or she loses the freedom of self-assessment, expression and choice. Or, he or she may be expected to choose when no longer able to do so. Thus, not only freedom but dignity also is lost, and lawyers join doctors in crisis manipulation and perpetuation. Although the modern medical culture has originated in the West, it has gradually spread to all parts of the world, subjugating other kinds of medical knowledge and other attitudes to dying and death.(ABSTRACT TRUNCATED AT 250 WORDS)

  18. Variabilität des Reviergesangs des Buchfinken (Fringilla coelebs) zur Raum-Zeit-Beschreibung von Metapopulationen

    NASA Astrophysics Data System (ADS)

    Nolte, Björn

    2003-10-01

    Der Buchfinkengesang wurde in Potsdam in zwei Hauptpopulationen über drei Jahre aufgenommen. Jedes Individuum wurde eindeutig am individuellen Strophentypenrepertoire identifiziert. Ein weiterer Punkt der die individuelle Wiedererkennung bestätigt ist die hohe Standorttreue der adulten Männchen. Die beschriebene Methode eignet sich für die Untersuchung von gesamten Populationen, um den Wandel des Gesangs von Populationen in Raum und Zeit zu beschreiben. Die Haupterkenntnisse der Arbeit sind: - Die Gesamtanzahl der Grundstrophentypen innerhalb einer Population bleibt über Jahre konstant. - Die relative Häufigkeit jedes einzelnen Strophentyps variiert von Jahr zu Jahr und von Population zu Population. - Gesangslernen erfolgt exakt mit einem Korrektheitsgrad von mindestens 96%. - Das Song-Sharing ist innerhalb der Population hoch. Die diskutierten Mechanismen für das Song-Sharing sind: Die Lebenserwartung, das Zugverhalten, das Lernverhalten, die Etabliertheit von Strophentypen, Weibchenpräferenzen und die Reaktionen der territorialen Männchen. - Weiterhin wurde ein Modell zur kulturellen Evolution des Buchfinkengesangs programmiert, um die Rolle der Einflussfaktoren, wie Fehlerquote, Abwanderungsrate und Laufzeit zu ermitteln. Der Wandel des Dialektes erfolgt graduell in Raum und Zeit. Daher sind keine scharfen Dialektgrenzen anzutreffen. Trotz dieser Tatsache markieren die etablierten Strophentypen die Population. 50 % der Juvenilen siedeln am Geburtsort, auf diese Weise bleibt der Dialekt erhalten und Inzest wird vermieden. -Analysiert man das Repertoire benachbarten Männchen bei isolierten Alleen, so entspricht die Gesangsangleichung in etwa dem Zufall. -Intraindividuelle Vergleiche der quantitativen Parameter des jeweiligen Strophentyps wurden saisonal und annuell durchgeführt. Saisonal konnten für einen Strophentyp ein Trend ermittelt werden. Bei jährlichen Vergleichen konnten intraindividuell ausschließlich nicht signifikante Ergebnisse ermittelt

  19. Cochlear Implants

    MedlinePlus

    ... outside of the body, behind the ear. A second part is surgically placed under the skin. An implant does not restore normal hearing. It can help a person understand speech. Children and adults can benefit from them. National Institute on Deafness and Other Communication Disorders

  20. Analyse und Entwurf von hochbitratigen Clock-and-Data-Recovery Schaltungen in CMOS-Technologie

    NASA Astrophysics Data System (ADS)

    Bremer, J.-K.; Zemko, C.; Schmackers, J.; Mathis, W.

    2007-06-01

    In dieser Arbeit wird ein neuartiges Schaltungskonzept für die Realisierung eines Phasendetektors einer Clock-and-Data-Recovery Schaltung vorgestellt. Es handelt sich hierbei um eine nichtlineare Phasendetektorarchitektur, die nach dem Verfahren von Alexander arbeitet. Um die Funktionalität des Phasendetektors im Hochfrequenzbereich zu gewährleisten, wurden in dem Design sehr schnell schaltende HLO-Flip-Flops (high-speed latching operation flip-flop) verwendet. Ein wesentliches Entwurfsziel war die Begrenzung des selbstgenerierten Jitters des Phasendetektors. Der Schaltungsentwurf wurde mit der Simulationsumgebung Cadence Spectre durchgeführt und die Funktionalität der Schaltung im GHz-Bereich anhand von ausgewählten Simulationen verifiziert. This paper presents a novel realization concept for Clock-and-Data-Recovery circuits. Our Design uses a nonlinear phase detector architecture, which is based on the Alexander phase detection method. In order to ensure circuit functionality in the RF region, we use very fast switching HLO-Flip-Flops (high-speed latching operation flip-flop) in our design. The primal goal in our design was the minimization of self induced jitter of the phase detector. The accuracy of our circuit design and the functionality in the GHz regime is confirmed by various circuit simulations executed with the SPECTRE Simulator.

  1. Accurate defect die placement and nuisance defect reduction for reticle die-to-die inspections

    NASA Astrophysics Data System (ADS)

    Wen, Vincent; Huang, L. R.; Lin, C. J.; Tseng, Y. N.; Huang, W. H.; Tuo, Laurent C.; Wylie, Mark; Chen, Ellison; Wang, Elvik; Glasser, Joshua; Kelkar, Amrish; Wu, David

    2015-10-01

    Die-to-die reticle inspections are among the simplest and most sensitive reticle inspections because of the use of an identical-design neighboring-die for the reference image. However, this inspection mode can have two key disadvantages: (1) The location of the defect is indeterminate because it is unclear to the inspector whether the test or reference image is defective; and (2) nuisance and false defects from mask manufacturing noise and tool optical variation can limit the usable sensitivity. The use of a new sequencing approach for a die-to-die inspection can resolve these issues without any additional scan time, without sacrifice in sensitivity requirement, and with a manageable increase in computation load. In this paper we explore another approach for die-to-die inspections using a new method of defect processing and sequencing. Utilizing die-to-die double arbitration during defect detection has been proven through extensive testing to generate accurate placement of the defect in the correct die to ensure efficient defect disposition at the AIMS step. The use of this method maintained the required inspection sensitivity for mask quality as verified with programmed-defectmask qualification and then further validated with production masks comparing the current inspection approach to the new method. Furthermore, this approach can significantly reduce the total number of defects that need to be reviewed by essentially eliminating the nuisance and false defects that can result from a die-to-die inspection. This "double-win" will significantly reduce the effort in classifying a die-to-die inspection result and will lead to improved cycle times.

  2. Von Hippel-Lindau Disease

    MedlinePlus

    Von Hippel-Lindau disease (VHL) is a rare, genetic disease that causes tumors and cysts to grow in your body. The tumors can be either ... and, in men, their genital tract. Symptoms of VHL vary and depend on the size and location ...

  3. Where people die.

    PubMed Central

    Katz, B P; Zdeb, M S; Therriault, G D

    1979-01-01

    Death certificates for 1977 filed with the New York State Department of Health were studied to determine where people died. Data were examined by the location and cause of death and by the age, sex, race, and marital status of the decedent. Comparisons were made with a similar study in which U.S. data were used for 1958 events. Approximately 60 percent of all the 1977 deaths in upstate New York occurred in hospitals; only 27 percent occurred outside an institution. The location of death varied by all the factors studied. Within all age categories, males had a higher percentage of hospital deaths. In those age categories in which nursing home deaths comprised a significant proportion of total deaths, females had a higher percentage of such deaths than males. Differences in the location of death according to its cause reflect the nature of the cause of death, for example, whether it was of sudden onset or the result of chronic disease. Most people do not consider in advance where they might die. The idea that age, sex, and marital status, as well as the more obvious cause, all play a part in the location may seem surprising. Yet all these factors were found to be associated withe location of deaths in upstate New York, and there is no reason to believe that this association does not hold true for the entire nation. More research, however, needs to be done based on more years and other geographic artal stutus may be instructive as to the present state of health resources. PMID:515338

  4. Darwin, Engels und die Rolle der Arbeit in der biologischen und kulturellen Evolution des Menschen

    NASA Astrophysics Data System (ADS)

    Reichholf, Josef H.

    Im Jahre 1876, 5 Jahre nach Erscheinen von Darwins Buch über die Evolution des Menschen und die sexuelle Selektion (Darwin 1871), veröffentlichte Friedrich Engels den berühmt gewordenen Essay "Anteil der Arbeit an der Menschwerdung des Affen“ (Engels 1876). Die Kernfrage darin lautet in Kurzform: Warum hat der Mensch eigentlich ein Bedürfnis nach Arbeit? Engels Antwort wird nachfolgend näher betrachtet und vom gegenwärtigen Kenntnisstand aus beurteilt. Wie sich zeigen wird, beantworten seine Überlegungen die Frage nicht wirklich. Sie ist weiterhin offen. Es können lediglich einige zusätzliche Anhaltspunkte zur Diskussion gestellt werden. Angesichts des drängenden Problems millionenfacher Arbeitslosigkeit und der Forderungen nach einem "Grundrecht auf Arbeit“ kommt den Überlegungen zum möglichen Ursprung des Bedürfnisses nach Arbeit mehr als nur akademisches Interesse zu.

  5. Maintaining Low Voiding Solder Die Attach for Power Die While Minimizing Die Tilt

    SciTech Connect

    Hamm, Randy; Peterson, Kenneth A.

    2015-10-01

    This paper addresses work to minimize voiding and die tilt in solder attachment of a large power die, measuring 9.0 mm X 6.5 mm X 0.1 mm (0.354” x 0.256” x 0.004”), to a heat spreader. As demands for larger high power die continue, minimizing voiding and die tilt is of interest for improved die functionality, yield, manufacturability, and reliability. High-power die generate considerable heat, which is important to dissipate effectively through control of voiding under high thermal load areas of the die while maintaining a consistent bondline (minimizing die tilt). Voiding was measured using acoustic imaging and die tilt was measured using two different optical measurement systems. 80Au-20Sn solder reflow was achieved using a batch vacuum solder system with optimized fixturing. Minimizing die tilt proved to be the more difficult of the two product requirements to meet. Process development variables included tooling, weight and solder preform thickness.

  6. Graphite/Thermoplastic-Pultrusion Die

    NASA Technical Reports Server (NTRS)

    Wilson, Maywood L.; Frye, Mark W.; Johnson, Gary S.; Stanfield, Clarence E.

    1990-01-01

    Attachment to extruder produces thermoplastic-impregnated graphite tape. Consists of profile die, fiber/resin collimator, and crosshead die body. Die designed to be attached to commercially available extrusion machine capable of extruding high-performance thermoplastics. Simple attachment to commercial extruder enables developers of composites to begin experimenting with large numbers of proprietary resins, fibers, and hybrid composite structures. With device, almost any possible fiber/resin combination fabricated.

  7. Die Milchstraße.

    NASA Astrophysics Data System (ADS)

    Henbest, N.; Couper, H.

    This book is a German translation, by M. Röser, from the English original "The guide to the Galaxy", published in 1994 (see Abstr. 61.003.065). Contents: 1. Die Entdeckung unserer Galaxis. 2. Die Lokale Gruppe. 3. Die Geographie der Galaxis. 4. Der Perseus-Arm. 5. Der Orion-Arm. 6. Unsere lokale Nachbarschaft: ein typischer Winkel der Galaxis. 7. Der Sagittarius-Arm: innerhalb der Sonnenumlaufbahn. 8. Das Zentrum der Galaxis.

  8. Systemlieferant und OEM Hersteller für die Medizintechnik und Pharmabranche

    NASA Astrophysics Data System (ADS)

    Jakob, Thomas; Reichenberger, Robert

    Unter einem Original Equipment Manufacturer (OEM) versteht man einen Hersteller fertiger Komponenten oder Produkte, der diese in seinen eigenen Produktionsfabriken produziert, sie aber anschließend nicht selbst in den Handel bringt. Die Anforderungen an einen OEM für die Medizintechnik- und Pharmabranche sind weitaus komplexer und umfangreicher als in anderen Branchen. Diese zusätzlichen Anforderungen haben schließlich auch ihre Berechtigung, da es letztendlich immer um die Gesundheit und das Leben von Menschen geht. Ein OEM muss neben der heute immer stärker geforderten Flexibilität, Schnelligkeit und Wettbewerbsfähigkeit sämtliche für die Medizintechnik- und Pharmabranche erforderlichen Qualitäts- und Prozesssicherheitskriterien erfüllen. Entsprechende Nachweise sind durch regelmäßige Kunden- und Überwachungsaudits zu erbringen. Das Arbeitsumfeld eines OEM für die Medizintechnik- und Pharmabranche bezieht sich somit nicht nur auf die Herstellung der Produkte für seine Kunden, sondern auch auf die Einhaltung sämtlicher Normen, Sicherheitskriterien, regulatorischen Voraussetzungen und Gesetze die zur Herstellung der Produkte notwendig sind.

  9. Kopplung eines auf der Momentenmethode basierenden Computerprogramms mit einem FEM-Algorithmus zur Berechnung von elektromagnetischen Streuproblemen im medizinischen Bereich

    NASA Astrophysics Data System (ADS)

    Schick, M.; Landstorfer, F. M.

    2004-05-01

    Am Beispiel der Verkopplung von medizinischen Geräten über den menschlichen Körper werden elektromagnetische Störphänomene im Klinikbereich betrachtet. Für die Berechnung dieser komplexen Szenarien wird zum einen die Momentenmethode (MoM) verwendet, die sich in besonderem Maße für die Berücksichtigung metallischer Strukturen und offener Streuprobleme eignet, und zum anderen die Methode der Finiten Elemente (FEM), mit der die Eigenschaften des menschlichen Körpers besser berücksichtigt werden können. Mit Hilfe des Äquivalenzprinzips lässt sich das Gesamtproblem in zwei Teile zerlegen, in ein inneres und in ein äußeres. Der Außenraum wird dabei mit der MoM behandelt und das Innere, d.h. der Körper mit der FEM. Die Kopplung der beiden Methoden erfolgt an der Körperoberfläche über äquivalente Oberflächenströme. Durch Lösen des resultierenden linearen Gleichungssystems für das gesamte Problem lassen sich dann die Oberflächenströme und die über die Kontinuitätsgleichung miteinander verknüpften elektromagnetischen Felder bestimmen.

  10. [Was Klaus von Mantrei the teacher of Hans von Gersdorff?].

    PubMed

    Vollmuth, R

    1996-01-01

    One of the most popular representatives of surgery at the end of the middle ages and the beginning modern era is the Strassburgian surgeon Hans von Gersdorff. Still we do not know very much about his life and his surgical teachers. Only one meister Nicklaus, called Mulartzt, is mentioned as such by the remarks in Gersdorffs 'Feldbuch der Wundarznei', but till today this surgeon could not be identified in more detail. This article now holds the thesis, that meister Nicklaus is probably identical with Klaus von Matrei (Metry), a well-known surgeon of the late 15th century. That cannot be fully proved yet, but a number of coinciding characteristics between the two and some further indications, that are explained, seem so significant, that the thesis can hardly be doubted.

  11. Short Implants: New Horizon in Implant Dentistry.

    PubMed

    Jain, Neha; Gulati, Manisha; Garg, Meenu; Pathak, Chetan

    2016-09-01

    The choice of implant length is an essential factor in deciding the survival rates of these implants and the overall success of the prosthesis. Placing an implant in the posterior part of the maxilla and mandible has always been very critical due to poor bone quality and quantity. Long implants can be placed in association with complex surgical procedures such as sinus lift and bone augmentation. These techniques are associated with higher cost, increased treatment time and greater morbidity. Hence, there is need for a less invasive treatment option in areas of poor bone quantity and quality. Data related to survival rates of short implants, their design and prosthetic considerations has been compiled and structured in this manuscript with emphasis on the indications, advantages of short implants and critical biomechanical factors to be taken into consideration when choosing to place them. Studies have shown that comparable success rates can be achieved with short implants as those with long implants by decreasing the lateral forces to the prosthesis, eliminating cantilevers, increasing implant surface area and improving implant to abutment connection. Short implants can be considered as an effective treatment alternative in resorbed ridges. Short implants can be considered as a viable treatment option in atrophic ridge cases in order to avoid complex surgical procedures required to place long implants. With improvement in the implant surface geometry and surface texture, there is an increase in the bone implant contact area which provides a good primary stability during osseo-integration.

  12. Short Implants: New Horizon in Implant Dentistry

    PubMed Central

    Gulati, Manisha; Garg, Meenu; Pathak, Chetan

    2016-01-01

    The choice of implant length is an essential factor in deciding the survival rates of these implants and the overall success of the prosthesis. Placing an implant in the posterior part of the maxilla and mandible has always been very critical due to poor bone quality and quantity. Long implants can be placed in association with complex surgical procedures such as sinus lift and bone augmentation. These techniques are associated with higher cost, increased treatment time and greater morbidity. Hence, there is need for a less invasive treatment option in areas of poor bone quantity and quality. Data related to survival rates of short implants, their design and prosthetic considerations has been compiled and structured in this manuscript with emphasis on the indications, advantages of short implants and critical biomechanical factors to be taken into consideration when choosing to place them. Studies have shown that comparable success rates can be achieved with short implants as those with long implants by decreasing the lateral forces to the prosthesis, eliminating cantilevers, increasing implant surface area and improving implant to abutment connection. Short implants can be considered as an effective treatment alternative in resorbed ridges. Short implants can be considered as a viable treatment option in atrophic ridge cases in order to avoid complex surgical procedures required to place long implants. With improvement in the implant surface geometry and surface texture, there is an increase in the bone implant contact area which provides a good primary stability during osseo-integration. PMID:27790598

  13. I Could Have Died Laughing.

    ERIC Educational Resources Information Center

    Maher, Michael Forrest; Smith, Douglas

    1993-01-01

    Notes that caregivers of the dying would do well to consider the prescriptive power of humor when confronting the challenges of healthy care for the terminally ill. Addresses laughter as the best medicine not only for the dying person but also for family and principal caregivers. Includes examples of therapeutic use of humor with the terminally…

  14. Untersuchung von asynchronen Timing-Strategien für digitale Subthreshold-Schaltungen

    NASA Astrophysics Data System (ADS)

    Lotze, N.; Ortmanns, M.; Manoli, Y.

    2008-05-01

    Eine der großen Herausforderungen beim Betrieb von Schaltungen bei extrem niedrigen Versorgungsspannungen ist die starke Zunahme des Einflusses zufälliger Prozessvariationen auf die Verzögerungszeiten der Gatter. Dies erfordert sehr hohe Sicherheitsmargen im Timing der Schaltungen, was zu einer deutlichen Verringerung der Geschwindigkeit und einem Anstieg der Energie pro Operation führt. Asynchrone Schaltungstechniken, die durch ihre Kodierung das Ende einer Operation detektieren können, sind daher bei dieser Anwendung eine interessante Alternative. In dieser Veröffentlichung werden die notwendigen Sicherheitsmargen in Delay-Line basierten Subthreshold-Schaltungen diskutiert und mögliche asynchrone Dual-Rail Entwurfsmethoden vorgestellt. Transistor-Level Simulationsergebnisse für einen einfachen, in den diskutierten Techniken realisierten Zähler werden vorgestellt, um die Funktionsfähigkeit dieser Techniken im Subthreshold-Bereich zu demonstrieren. Multiplizier mit unterschiedlicher Wortbreite dienen als Beispiel für eine komplexere Schaltung, welche bezüglich Geschwindigkeit, Energiebedarf und Flächenaufwand mit einer entsprechenden Standard-Realisierung verglichen wird, was abschließend eine Aussage darüber zulässt, wann die untersuchten Techniken gewinnbringend eingesetzt werden können.

  15. Optimierung von FSS-Bandpassfiltern mit Hilfe der Schwarmintelligenz (Particle Swarm Optimization)

    NASA Astrophysics Data System (ADS)

    Wu, G.; Hansen, V.; Kreysa, E.; Gemünd, H.-P.

    2006-09-01

    In diesem Beitrag wird ein neues Verfahren zur Optimierung von Bandpassfiltern aus mehrlagigen frequenzselektiven Schirmen (FSS), die in ein Dielektrikum eingebettet sind, vorgestellt. Das Ziel ist es, die Parameter der gesamten Struktur so zu optimieren, dass ihre Transmissionseigenschaften hohe Filteranforderungen erfüllen. Als Optimierungsverfahren wird die Particle Swarm Optimization (PSO) eingesetzt. PSO ist eine neue stochastische Optimierungsmethode, die in verschieden Gebieten, besonders aber bei der Optimierung nicht linearer Probleme mit mehreren Zielfunktionen erfolgreich eingesetzt wird. In dieser Arbeit wird die PSO in die Spektralbereichsanalyse zur Berechnung komplexer FSS-Strukturen integriert. Die numerische Berechnung basiert auf einer Integralgleichungsformulierung mit Hilfe der spektralen Greenschen Funktion für geschichtete Strukturen. This paper presents a novel procedure for the optimization of band-pass filters consisting of frequency selective surfaces (FSS) embedded in a dielectric. The aim is to optimize the parameters of the complete structure so that the transmission characteristics of the filters fulfill the demanding requirements. The Particle Swarm Optimization (PSO) is used as the optimization procedure. PSO is a new stochastic optimization method that is successfully applied in different areas for the optimization of non-linear problems with several object-functions. In this work, PSO is integrated into the spectral domain analysis for the calculation of the complex FSS structures. The numerical computation is based on the formulation of an integral equation with the help of the spectral Green's function for layered media.

  16. Adapt or die?

    PubMed

    Visser, S S; Nel, A H

    1996-12-01

    The worldwide economic recession and the concomitant limited stock of finances have had an influence on the available money of every household and have also inhibited the improvement of socio-economic conditions and medicine. The Reconstruction and Development Programme (RDP) has the objective of improving the living conditions of the people with regard to housing, education, training and health care. The latter seems to be a major problem which has to be addressed with the emphasis on the preventive and promotional aspects of health care. A comprehensive health care system did not come into being property in the past because of the maldistribution of health care services, personnel and differences in culture and health care beliefs and values. The question that now arises, is how to render a quality health care service within the constraints of inadequate financing and resources. A comprehensive literature study has been done with reference to quality health care and financing followed by a survey of existing health services and finances. Recommendations are made about minimum requirements to be accepted if one were to adapt rather than die in terms of the provision of healthcare: the decentralization and rationalization of the administration of health care, the stress on and realization of effective and efficient primary health care, the acceptance of participative management in health providing organizations, the provision of financial management training for health care managers and the application of management accounting principles for the improvement of the efficiency and effectiveness of management.

  17. Two Piece Compaction Die Design

    SciTech Connect

    Coffey, Ethan N

    2010-03-01

    Compaction dies used to create europium oxide and tantalum control plates were modeled using ANSYS 11.0. Two-piece designs were considered in order to make the dies easier to assemble than the five-piece dies that were previously used. The two areas of concern were the stresses at the interior corner of the die cavity and the distortion of the cavity wall due to the interference fit between the two pieces and the pressure exerted on the die during the compaction process. A successful die design would have stresses less than the yield stress of the material and a maximum wall distortion on the order of 0.0001 in. Design factors that were investigated include the inner corner radius, the value of the interference fit, the compaction force, the size of the cavity, and the outer radius and geometry of the outer ring. The results show that for the europium oxide die, a 0.01 in. diameter wire can be used to create the cavity, leading to a 0.0055 in. radius corner, if the radial interference fit is 0.003 in. For the tantalum die, the same wire can be used with a radial interference fit of 0.001 in. Also, for the europium oxide die with a 0.003 in. interference fit, it is possible to use a wire with a diameter of 0.006 in. for the wire burning process. Adding a 10% safety factor to the compaction force tends to lead to conservative estimates of the stresses but not for the wall distortion. However, when the 10% safety factor is removed, the wall distortion is not affected enough to discard the design. Finally, regarding the europium oxide die, when the cavity walls are increased by 0.002 in. per side or the outer ring is made to the same geometry as the tantalum die, all the stresses and wall distortions are within the desired range. Thus, the recommendation is to use a 0.006 in. diameter wire and a 0.003 in. interference fit for the europium oxide die and a 0.01 in. diameter wire and a 0.001 in. interference fit for the tantalum die. The dies can also be made to have the

  18. Treatment of von Willebrand Disease.

    PubMed

    Curnow, Jennifer; Pasalic, Leonardo; Favaloro, Emmanuel J

    2016-03-01

    Congenital von Willebrand disease (VWD) and acquired von Willebrand syndrome (AVWS) reflect conditions caused by von Willebrand factor (VWF) deficiency and/or defects. VWD is the most common inherited bleeding disorder and AVWS arises from a variety of causes. Since VWF stabilizes and protects factor VIII (FVIII) in the circulation, this is also reduced in many patients with VWD. The treatment of VWD and AVWS therefore primarily entails replacement of VWF, and sometimes FVIII, to protect against bleeding. This may entail the use of VWF concentrates (currently plasma-derived) and/or FVIII concentrates (currently plasma-derived or more increasingly recombinant forms), and/or desmopressin to release endogenous VWF in subgroups of patients. For AVWS additional treatment of the underlying condition is also required. Adjunct therapies include antifibrinolytics. Globally, various formulations exist for both VWF and FVIII concentrates and are differentially available based on manufacturer marketing or regulatory approvals/clearances in different geographies. Also, guidelines for treatment of VWD vary for different localities and recombinant VWF is undergoing clinical trials. The current review provides an overview of the treatment of VWD as currently practiced in developed countries, and also provides a glimpse towards the future.

  19. Technische Systeme für den Herzersatz und die Herzunterstützung

    NASA Astrophysics Data System (ADS)

    Schöb, Reto; Loree, Howard M.

    Herzkrankheiten verursachen allein in den Vereinigten Staaten jährlich mehr als 700’000 Todesfälle. Ungefähr 3 Millionen Patienten in den U.S.A. leiden gemäss der American Heart Association (AHA) und dem National Heart, Lung and Blood Institute (NHLBI) an kongestivem Herzversagen (Congestive Heart Failure, CHF), welches eine chronische, sehr entkräftende und degenerative Krankheit ist: Das Herz ist dabei unfähig, hinreichend Blut zu den Organen des Körpers zu pumpen. Über 400’000 Fälle von CHF werden jedes Jahr diagnostiziert. Ähnliche Zahlen werden für Europa und Japan zusammen geschätzt. Basierend auf Daten vom AHA und NHLBI beträgt die fünfjährige Überlebensrate für CHF-Patienten lediglich etwa 50% [1]. 70’000-120’000 dieser Patienten könnten von einer Herzverpflanzung profitieren. 1999 wurden in den USA aber nur 2185 Herztransplantationen durchgeführt während die Warteliste über 4000 Patienten beträgt [2]. Ein akuter Mangel an Spenderherzen und die enormen Kosten (250’000-400’000 USD pro Patient) sind die begrenzenden Faktoren für Herztransplantationen [3]. Dies bedeutet, dass eine riesige Anzahl von Patienten durch ein zuverlässiges und verschleissfreies, nichtthrombotisches, total implantierbares, künstliches Herz gerettet werden könnten. Bis heute jedoch kein derartiges Implantat kommerziell verfügbar.

  20. Zelltyp-spezifische Mikroanalyse von Arabidopsis thaliana-Blättern

    NASA Astrophysics Data System (ADS)

    Brandt, Stephan Peter

    2002-04-01

    Im ersten Teil der Arbeit wurden Strategien zur Analyse von Transkripten erarbeitet. Die ersten Versuche zielten darauf ab, in mit Glaskapillaren genommenen Einzelzellproben verschiedener Gewebeschichten RT-PCR durchzuführen, um spezifische Transkripte nachweisen zu können. Dies gelang für eine Reihe von Genen aus verschiedenen Pflanzenspezies. Dabei konnten sowohl Transkripte stark wie auch schwach exprimierter Gene nachgewiesen werden. Für die Erstellung von Gewebe-spezifischen Expressionsprofilen war es notwendig, die in vereinigten Zellproben enthaltene mRNA zunächst zu amplifizieren, um eine ausreichende Menge für Arrayhybridisierungen zu erhalten. Vor der Vermehrung wurde die mRNA revers transkribiert. Es wurden daran anschließend verschiedene Amplifikationsstrategien getestet: Die neben Tailing, Adapterligation und anderen PCR-basierenden Protokollen getestete Arbitrary-PCR hat sich in dieser Arbeit als einfache und einzige Methode herausgestellt, die mit so geringen cDNA-Mengen reproduzierbar arbeitet. Durch Gewebe-spezifische Array-hybridisierungen mit der so amplifizierten RNA konnten schon bekannte Expressionsmuster verschiedener Gene, vornehmlich solcher, die an der Photosynthese beteiligt sind, beobachtet werden. Es wurden aber auch eine ganze Reihe neuer offensichtlich Gewebe-spezifisch exprimierter Gene gefunden. Exemplarisch für die differentiell exprimierten Gene konnte das durch Arrayhybridisierungen gefundene Expressionsmuster der kleinen Untereinheit von Rubisco verifiziert werden. Hierzu wurden Methoden zum Gewebe-spezifischen Northernblot sowie semiquantitativer und Echtzeit-Einzelzell-RT-PCR entwickelt. Im zweiten Teil der Arbeit wurden Methoden zur Analyse von Metaboliten einschließlich anorganischer Ionen verwendet. Es stellte sich heraus, daß die multiparallele Methode der Gaschromatographie-Massenspektrometrie keine geeignete Methode für die Analyse selbst vieler vereinigter Zellinhalte ist. Daher wurde auf

  1. Dr. von Braun Briefing Walt Disney

    NASA Technical Reports Server (NTRS)

    1965-01-01

    Dr. von Braun began his association with Walt Disney in the 1950s when the rocket scientist appeared in three Disney television productions related to the exploration of space. Years later, Dr. von Braun invited Disney and his associates to tour the Marshall Space Flight Center (MSFC) in Huntsville, Alabama. This photograph is dated April 13, 1965. From left are R.J. Schwinghamer from the MSFC, Disney, B.J. Bernight, and Dr. von Braun.

  2. A two-short-implant-supported molar restoration in atrophic posterior maxilla: A finite element analysis

    PubMed Central

    2016-01-01

    PURPOSE The aim of this study was to investigate the stress distribution of 2-short implants (2SIs) installed in a severely atrophic maxillary molar site. MATERIALS AND METHODS Three different diameters of internal connection implants were modeled: narrow platform (NP), regular platform (RP), and wide platform (WP). The maxillary first molars were restored with one implant or two short implants. Three 2SI models (NP-oblique, NP-vertical, and NP-horizontal) and four single implant models (RP and WP in a centered or cantilevered position) were used. Axial and oblique loadings were applied on the occlusal surface of the crown. The von Mises stress values were measured at the bone-implant, peri-implant bone, and implant/abutment complex. RESULTS The highest stress distribution at the bone-implant interface and the peri-implant bone was noticed in the RP group, and the lowest stress distribution was observed in the 2SI groups. Cantilevered position showed unfavorable stress distribution with axial loading. 2SI types did not affect the stress distribution in oblique loading. The number and installation positions of the implant, rather than the bone level, influenced the stress distribution of 2SIs. The implant/abutment complex of WP presented the highest stress concentration while that of 2SIs showed the lowest stress concentration. CONCLUSION 2SIs may be useful for achieving stable stress distribution on the surrounding bone and implant-abutment complex in the atrophic posterior maxilla. PMID:27555900

  3. Dental Implant Surgery

    MedlinePlus

    Dental implant surgery Overview By Mayo Clinic Staff Dental implant surgery is a procedure that replaces tooth roots with ... look and function much like real ones. Dental implant surgery can offer a welcome alternative to dentures ...

  4. Hip Implant Systems

    MedlinePlus

    ... Devices Products and Medical Procedures Implants and Prosthetics Metal-on-Metal Hip Implants Hip Implants Share Tweet Linkedin Pin ... devices available with different bearing surfaces. These are: Metal-on-Polyethylene: The ball is made of metal ...

  5. Dying: A universal human experience?

    PubMed

    Bregman, L

    1989-03-01

    This paper explores the question, "Is there a universal psychological experience suffered by all dying persons?" a question to which the popular theory of Kübler-Ross presupposes an affirmative answer. Our answer takes three steps: first, a comparison between the Kübler-Ross model of dying and that of the late medievalBook of the Craft of Dying centered upon the five Kübler-Ross "stages"; second, a philosophical critique of the terms of this comparison; and third, a revised look at the alleged similarities between the two models, providing a deeper look at the moral and spiritual assumptions behind each.

  6. Versuche zur Gewinnung von katalytischen Antikörpern zur Hydrolyse von Arylcarbamaten und Arylharnstoffen. (English Title: Attempts to produce catalytic antibodies for hydrolysis of arylcarbamates and arylureas)

    NASA Astrophysics Data System (ADS)

    Werner, Deljana

    2002-05-01

    Im Rahmen dieser Arbeit gelang es, katalytische Antikörper zur Hydrolyse von Benzylphenylcarbamaten sowie zahlreiche monoklonale Antikörper gegen Haptene herzustellen. Es wurden verschiedene Hapten-Protein-Konjugate unter Verwendung unterschiedlicher Kopplungsmethoden hergestellt und charakterisiert. Zur Generierung der hydrolytisch aktiven Antikörper wurden Inzuchtmäuse mit KLH-Konjugaten von 4 Übergangszustandsanaloga (ÜZA) immunisiert. Mit Hilfe der Hybridomtechnik wurden verschiedene monoklonale Antikörper gegen diese ÜZA gewonnen. Dabei wurden sowohl verschiedene Immunisierungsschemata als auch verschiedene Inzuchtmausstämme und Fusionstechniken verwendet. Insgesamt wurden 32 monoklonale Antikörper gegen die verwendeten ÜZA selektiert. Diese Antikörper wurden in groen Mengen hergestellt und gereinigt. Zum Nachweis der Antikörper-vermittelten Katalyse wurden verschiedene Methoden entwickelt und eingesetzt, darunter immunologische Nachweismethoden mit Anti-Substrat- und Anti-Produkt-Antikörpern und eine photometrische Methode mit Dimethylaminozimtaldehyd. Der Nachweis der hydrolytischen Aktivität gelang mit Hilfe eines Enzymsensors, basierend auf immobilisierter Tyrosinase. Die Antikörper N1-BC1-D11, N1-FA7-C4, N1-FA7-D12 und R3-LG2-F9 hydrolysierten die Benzylphenylcarbamate POCc18, POCc19 und Substanz 27. Der Nachweis der hydrolytischen Aktivität dieser Antikörper gelang auch mit Hilfe der HPLC. Der katalytische Antikörper N1-BC1-D11 wurde kinetisch und thermodynamisch untersucht. Es wurde eine Michaelis-Menten-Kinetik mit Km von 210 µM, vmax von 3 mM/min und kcat von 222 min-1 beobachtet. Diese Werte korrelieren mit den Werten der wenigen bekannten Diphenylcarbamat-spaltenden Abzyme. Die Beschleunigungsrate des Antikörpers N1-BC1-D11 betrug 10. Das ÜZA Hei3 hemmte die hydrolytische Aktivität. Dies beweist, dass die Hydrolyse in der Antigenbindungsstelle stattfindet. Weiter wurde zwischen der Antikörperkonzentration und der

  7. Ultrafine-grained titanium for medical implants

    DOEpatents

    Zhu, Yuntian T.; Lowe, Terry C.; Valiev, Ruslan Z.; Stolyarov, Vladimir V.; Latysh, Vladimir V.; Raab, Georgy J.

    2002-01-01

    We disclose ultrafine-grained titanium. A coarse-grained titanium billet is subjected to multiple extrusions through a preheated equal channel angular extrusion (ECAE) die, with billet rotation between subsequent extrusions. The resulting billet is cold processed by cold rolling and/or cold extrusion, with optional annealing. The resulting ultrafine-grained titanium has greatly improved mechanical properties and is used to make medical implants.

  8. Vorhersage des Krankheitsverlaufes von leichten kognitiven Beeinträchtigungen durch automatisierte MRT Morphometrie

    NASA Astrophysics Data System (ADS)

    Fritzsche, Klaus H.; Schlindwein, Sarah; Stieltjes, Bram; Essig, Marco; Meinzer, Hans-Peter

    Die leichte kognitive Beeinträchtigung (LKB) gilt als Anzeichen für ein erhöhtes Risiko der Entwicklung einer Alzheimerdemenz. Eine fundierte klinische Prognose für den Krankheitsverlauf kann aber bis dato nicht gegeben werden. Das Ziel dieser Arbeit besteht darin, eine möglichst präzise Vorhersage mittels automatisierter Morphometrie des Hippokampus im MRT-Bild zu treffen. In einer Studie mit 18 Probanden mit LKB wurde eine Prädiktionsgenauigkeit für die Entwicklung einer späteren Demenz von 83.3% erzielt. Eine manuelle Vergleichsmethode erreichte mit 55.6% Trefferquote keine signifikante Vorhersagegenauigkeit. Das automatische Verfahren erfüllt viele wichtige Voraussetzungen für den routinemäßigen klinischen Einsatz mit dem Potential, die klinische Vorhersage des Krankheitsverlaufes bei der LKB zu verbessern.

  9. Die Sonne, Stern unserer Erde

    NASA Astrophysics Data System (ADS)

    Lang, Kenneth R.; Ehlers, A.

    Dieses reich bebilderte Buch gibt eine Einführung in die Physik der Sonne und ihre Bedeutung für die Erde. Gestützt auf neueste Forschungsergebnisse aus Radioteleskop- und Satellitenbeobachtungen beschreibt der Autor die gewaltigen atomenergetischen Prozesse der Sonne, ihren geheimnisvollen Neutrinofluß, ihre seismischen Aktivitäten, Magnetfelder und Sonnenflecke, Korona, Sonnenausbrüche und Protuberanzen, den Sonnenwind, und die außerordentlich wichtige und vielfältige Bedeutung des Sonnenlichts, das Leben auf der Erde entstehen läßt und es auch gefährdet. Gut verständlich und in ansprechender Sprache geschrieben ist es ein wunderbares Buch für den Leser populärwissenschaftlicher Literatur, ein wertvolles Geschenk für Studenten der Astronomie und verwandter Disziplinen sowie Amateurastronomen.

  10. Biomechanical analysis of the effects of implant diameter and bone quality in short implants placed in the atrophic posterior maxilla.

    PubMed

    Chang, Shih-Hao; Lin, Chun-Li; Hsue, Shue-Sang; Lin, Yang-Sung; Huang, Shiang-Rung

    2012-03-01

    Short dental implant (SDI) placement has been proposed as an alternative to reduce the surgical risks related to the advanced grafting procedures. The aim of this study was to simulate the biomechanical behaviors and influences of SDI diameters under various conditions of bone quality by using a validated finite element (FE) model for simulation. The CT image and CAD system were combined to construct the FE models with 6 mm length SDIs for 6, 7 and 8 mm diameters under three types of bone qualities, from normal to osteoporotic. The simulated results showed that implant diameter did not influence the von Mises strains of bone under the vertical load. The bone strains increased about 58.58% in the bone of least density under lateral load. Lateral loads induced high bone strain and implant stress than vertical loads. The bone strains of 7 mm- and 8 mm-diameter short implants were not different, and both were about 52% and 66% compared to those of 6 mm-wide short implant under lateral loads. The von Mises stress of the SDIs and their compartments were all less than the yield stress of the material under vertical and lateral loads. SDIs with diameter of 7 mm or above may have better mechanical transmission in the same length at feasible condition. Attaining a proper occlusal scheme design or selective occlusal adjustments to reduce the lateral occlusal force upon the SDIs is recommended.

  11. REFRACTORY DIE FOR EXTRUDING URANIUM

    DOEpatents

    Creutz, E.C.

    1959-08-11

    A die is presented for the extrusion of metals, said die being formed of a refractory complex oxide having the composition M/sub n/O/sub m/R/sub x/O/sub y/ where M is magnesium, zinc, manganese, or iron, R is aluminum, chromic chromium, ferric iron, or manganic manganese, and m, n, x, and y are whole numbers. Specific examples are spinel, magnesium aluminate, magnetite, magnesioferrite, chromite, and franklinite.

  12. Dr. Wernher Von Braun at a picnic.

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Dr. Wernher Von Braun, director of the Marshall Space Flight Center, stakes claim to a table for the picnic celebrating man's first lunar landing. With Dr. Von Braun are his wife, Maria (seated, right), and son, Peter (back to camera). His daughter, Margrit, was also present, but is hidden from view by friends in this view.

  13. Dr. Wernher Von Braun greeting dignitaries.

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Dr. Wernher Von Braun, left, greets vice president Spiro T. Agnew in the Launch Control Center for the Apollo 14 mission. Between Dr. Von Braun and Mr. Agnew are their Royal Highnesses, The Prince and Princess of Spain. The royal visitors greeted the launch control team in th enter after the launch of Apollo 14.

  14. Dr. von Braun Tries Out the NBS

    NASA Technical Reports Server (NTRS)

    1967-01-01

    Marshall Space Flight Center (MSFC) Director, Dr. von Braun, is shown fitted with suit and diving equipment as he prepares for a tryout in the MSFC Neutral Buoyancy Simulator (NBS). Weighted to a neutrally buoyant condition, Dr. von Braun was able to perform tasks underwater which simulated weightless conditions found in space.

  15. Walt Disney and Dr. Wernher von Braun

    NASA Technical Reports Server (NTRS)

    1954-01-01

    Dr. Werhner von Braun, then Chief, Guided Missile Development Operation Division at Army Ballistic Missile Agency (ABMA) in Redstone Arsenal, Alabama, was visited by Walt Disney in 1954. In the 1950's, von Braun worked with Disney Studio as a technical director, making three films about space exploration for television. A model of the V-2 rocket is in background.

  16. Über die Kleinsignalgewinnmessung nach Ladenburg-Levy

    NASA Astrophysics Data System (ADS)

    Grunwald, R.; Hertz, J. H.

    Es werden die Möglichkeiten und Probleme der Anwendung einer alten Methode von Ladenburg-Levy zur Kleinsignalgewinnmessung in Niederdruck-Impulsgasentladungen diskutiert. Als Beispiel werden Ergebnisse der zeitaufgelösten Gewinnmessung am 2. Pos. System des Stickstoff ( = 337 nm) mitgeteilt.Translated AbstractOn the Small-Signal Gain Measurement According to Ladenburg-LevyThe application of an old method of Ladenburg-Levy to small-signal gain measurement in pulsed low pressure gas discharges as well as the problems connected with this method are discussed. As an example experimental results of time resolved gain measurements in the 2nd positive system of nitrogen ( = 337 nm) are presented.

  17. Dr. Wernher von Braun In His Office

    NASA Technical Reports Server (NTRS)

    1964-01-01

    Dr. Wernher von Braun served as Marshall Space Flight Center's first director from July 1, 1960 until January 27, 1970, when he was appointed NASA Deputy Associate Administrator for Planning. Following World War II, Dr. von Braun and his German colleagues arrived in the United States under Project Paperclip to continue their rocket development work. In 1950, von Braun and his rocket team were transferred from Ft. Bliss, Texas to Huntsville, Alabama to work for the Army's rocket program at Redstone Arsenal and later, NASA's Marshall Space Flight Center. Under von Braun's leadership, Marshall developed the Saturn V launch vehicle which took Apollo astronauts to the moon. This photo depicts von Braun in his office at MSFC.

  18. Alloantibodies in von Willebrand disease.

    PubMed

    James, Paula D; Lillicrap, David; Mannucci, Pier M

    2013-08-01

    The development of alloantibodies against von Willebrand factor (VWF) represents a rare but serious complication of treatment of von Willebrand disease (VWD), occurring in ~5% to 10% of type 3 VWD patients. Affected patients can present with a range of symptoms, including lack or loss of hemostatic response to infused VWF concentrates up to anaphylactic reactions in rare cases. It is classically reported in multitransfused patients and occurs most frequently in patients with partial or complete VWF gene deletions. A positive family history of anti-VWF antibodies also appears to be a risk factor. There is a lack of standardization of laboratory methods for antibody identification and characterization. Issues of variability in laboratory approaches as well as the rarity of the complication act as a barrier to future studies. Recombinant factor VIII as well as bypassing agents and immune tolerance have been reported as effective treatments; however, aside from case reports, little exists in the literature to guide management. The imminent clinical availability of recombinant VWF has prompted a resurgence of interest in this area. Additional study is warranted to address the deficiencies in our understanding of this treatment complication.

  19. Clearance of von Willebrand factor.

    PubMed

    Denis, Cécile V; Christophe, Olivier D; Oortwijn, Beatrijs D; Lenting, Peter J

    2008-02-01

    The life cycle of von Willebrand factor (VWF) comprises a number of distinct steps, ranging from the controlled expression of the VWF gene in endothelial cells and megakaryocytes to the removal of VWF from the circulation. The various aspects of VWF clearance have been the objects of intense research in the last few years, stimulated by observations that VWF clearance is a relatively common component of the pathogenesis of type 1 von Willebrand disease (VWD). Moreover, improving the survival of VWF is now considered as a viable therapeutic strategy to prolong the half-life of factor VIII in order to optimise treatment of haemophilia A. The present review aims to provide an overview of recent findings with regard to the molecular basis of VWF clearance. A number of parameters have been identified that influence VWF clearance, including its glycosylation profile and a number of VWF missense mutations. In addition, in-vivo studies have been used to identify cells that contribute to the catabolism of VWF, providing a starting point for the identification of receptors that mediate the cellular uptake of VWF. Finally, we discuss recent data describing chemically modification of VWF as an approach to prolong the half-life of the VWF/FVIII complex.

  20. [Bilateral cochlear implantation].

    PubMed

    Kronenberg, Jona; Migirov, Lela; Taitelbaum-Swead, Rikey; Hildesheimer, Minka

    2010-06-01

    Cochlear implant surgery became the standard of care in hearing rehabilitation of patients with severe to profound sensorineural hearing loss. This procedure may alter the lives of children and adults enabling them to integrate with the hearing population. In the past, implantation was performed only in one ear, despite the fact that binaural hearing is superior to unilateral, especially in noisy conditions. Cochlear implantation may be performed sequentially or simultaneously. The "sensitive period" of time between hearing loss and implantation and between the two implantations, when performed sequentially, significantly influences the results. Shorter time spans between implantations improve the hearing results after implantation. Hearing success after implantation is highly dependent on the rehabilitation process which includes mapping, implant adjustments and hearing training. Bilateral cochlear implantation in children is recommended as the proposed procedure in spite of the additional financial burden.

  1. Clinical management of dying patients.

    PubMed Central

    Gavrin, J; Chapman, C R

    1995-01-01

    Dying is universal, and death should be a peaceful time. Myriad comfort measures are available in the last weeks before life ends. Discussions about end-of-life issues often suffer from lack of informed opinion. Palliative care experts have identified specific somatic and psychological sources of distress for dying patients and their loved ones. Pain, shortness of breath, nausea and vomiting, and fear of abandonment contribute substantially to both physical and psychological discomfort toward the end of life. Simple, effective methods exist for relieving those symptoms. Knowledge about the natural events associated with dying and an informed approach to medical and psychological interventions contribute to systematic and successful comfort care. We describe the origin of physical and psychological distress at the end of life and provide strategies for alleviating many of the discomforts. PMID:7571591

  2. [Dying with cancer: Hollywood lessons].

    PubMed

    Niemeyer, Fernanda; Kruse, Maria Henriqueta Luce

    2013-12-01

    The study attempts to understand how dying from cancer is portrayed by five movies produced in Hollywood between 1993 and 2006. Based on the cultural studies and their post-structuralism version and supported by the notions of discourse and subjectivity, as proposed by philosopher Michel Foucault, we suggest one of the possible readings of the movie picture corpus. We assess how the movie picture discourse acts as a cultural pedagogy that produces ways of seeing dying with cancer: immortalizing the healthy body image, silencing death, taking care of the dead body and, finally, accepting death. Our proposal is intended to stimulate reflections that may contribute to care and education in nursing.

  3. Portable punch and die jig

    DOEpatents

    Lewandowski, Edward F.; Anderson, Petrus A.

    1978-01-01

    A portable punch and die jig includes a U-shaped jig of predetermined width having a slot of predetermined width in the base thereof extending completely across the width of the jig adapted to fit over the walls of rectangular tubes and a punch and die assembly disposed in a hole extending through the base of the jig communicating with the slot in the base of the jig for punching a hole in the walls of the rectangular tubes at precisely determined locations.

  4. A double commutant theorem for Murray–von Neumann algebras

    PubMed Central

    Liu, Zhe

    2012-01-01

    Murray–von Neumann algebras are algebras of operators affiliated with finite von Neumann algebras. In this article, we study commutativity and affiliation of self-adjoint operators (possibly unbounded). We show that a maximal abelian self-adjoint subalgebra of the Murray–von Neumann algebra associated with a finite von Neumann algebra is the Murray–von Neumann algebra , where is a maximal abelian self-adjoint subalgebra of and, in addition, is . We also prove that the Murray–von Neumann algebra with the center of is the center of the Murray–von Neumann algebra . Von Neumann’s celebrated double commutant theorem characterizes von Neumann algebras as those for which , where , the commutant of , is the set of bounded operators on the Hilbert space that commute with all operators in . At the end of this article, we present a double commutant theorem for Murray–von Neumann algebras. PMID:22543165

  5. Entwicklung von Landnutzungsszenarien für landschaftsökologische Fragestellungen

    NASA Astrophysics Data System (ADS)

    Fritsch, Uta

    2002-04-01

    Die Landschaften Mitteleuropas sind das Resultat einer langwierigen Geschichte menschlicher Landnutzung mit ihren unterschiedlichen, z.T. konkurrierenden Nutzungsansprüchen. Durch eine überwiegend intensive Beanspruchung haben die direkten und indirekten Auswirkungen der Landnutzung in vielen Fällen zu Umweltproblemen geführt. Die Disziplin der Landschaftsökologie hat es sich zur Aufgabe gemacht, Konzepte für eine nachhaltige Nutzung der Landschaft zu entwickeln. Eine wichtige Fragestellung stellt dabei die Abschätzung der möglichen Folgen von Landnutzungsänderungen dar. Für die Analyse der relevanten Prozesse in der Landschaft werden häufig mathematische Modelle eingesetzt, welche es erlauben die Landschaft unter aktuellen Verhältnissen oder hinsichtlich veränderter Rahmenbedingungen zu untersuchen. Die hypothetische Änderung der Landnutzung, die als Landnutzungsszenario bezeichnet wird, verkörpert eine wesentliche Modifikation der Rahmenbedingungen, weil Landnutzung mageblich Einfluss auf die natürlichen Prozesse der Landschaft nimmt. Während die Antriebskräfte einer solchen Änderung überwiegend von sozio-ökonomischen und politischen Entscheidungen gesteuert werden, orientiert sich die exakte Verortung der Landnutzungsänderungen an den naturräumlichen Bedingungen und folgt z.T. erkennbaren Regeln. Anhand dieser Vorgaben ist es möglich, räumlich explizite Landnutzungsszenarien zu entwickeln, die als Eingangsdaten für die Modellierung verschiedener landschaftsökologischer Fragestellungen wie z.B. für die Untersuchung des Einflusses der Landnutzung auf den Wasserhaushalt, die Erosionsgefahr oder die Habitatqualität dienen können. Im Rahmen dieser Dissertation wurde das rasterbasierte deterministische Allokationsmodell luck (Land Use Change Scenario Kit) für die explizite Verortung der Landnutzungsänderungen entwickelt. Es basiert auf den in der Landschaftsökologie üblichen räumlichen Daten wie Landnutzung, Boden sowie Topographie

  6. Attitudes on Death and Dying.

    ERIC Educational Resources Information Center

    Andrus, Charles E.

    This paper explored attitudes toward death and dying revealed through interviews with members of the clergy, the medical profession, funeral directors, nursing home residents, and selected others. The sampling was small and results are not intended to be representative of the groups to which these people belong. Rather, the study may be used as a…

  7. Robert Merton Dies at 92

    ERIC Educational Resources Information Center

    Snell, Joel C.

    2006-01-01

    This article features Robert Merton, who died recently at age 92. Merton came into this world as a Jewish baby named Meyer Schkolnick. He lived in South Philly where his parents wrenched a living as blue-collar workers. Merton chose an Anglicized name to move into the Yankee dominated America of the 20's and 30's. At Harvard, he studied under…

  8. Die Cnidogenese der Octocorallia (Anthozoa, Cnidaria): II. Reifung, Wanderung und Zerfall von Cnidoblast und Nesselkapsel

    NASA Astrophysics Data System (ADS)

    Schmidt, H.; Moraw, B.

    1982-03-01

    Migration of cnidoblasts has never been observed in Anthozoa. In contrast to hydrozoans, anthozoans are repeatedly reported to develop nematocysts locally without migration in the entoderm as well as in the ectoderm. The majority of the nematocysts studied in different Octocorallia species (Alcyonaria: Alcyonarium digitatum, Parerythropodium coralloides; Gorgonaria: Pseudopterogorgia aerosa; Pennatularia: Veretillum cynomorium) originate from the ectoderm of the scapus, where, however, no mature nematocysts occur. Cnidoblasts containing immature nematocysts accumulate in the distal scapus, from where they migrate singly like amoebae into the pinnulae of the tentacles. The nematocysts mature during migration, during which the capsular matrix becomes completely electron-translucent. Only in the oral disc, where few nematocysts occur, do they mature locally without migration. In the Octocorallia, nematocyst development and maturation takes places only in the ectoderm. Development of nematocysts has never been observed in the entoderm, nor in the pharynx; this demonstrates its entodermal origin. The entoderm contains only degenerated or phagocytized nematocysts. Contrary to hydrozoans, the mature anthozoan cnidocyte is rounded and has no processes to the mesogloea. Instead of a cnidocil it has a ciliary cone consisting of a normal flagellum, stereocilia and macrovilli. The cnidocyte is characterised by abundant electron-translucent cytoplasm and nematocyst-anchoring structures made up of cross-striated, collagen-like fibrillae and a fibrous basal ring. The position of the cross-striated fibrillae is distally similar to that of the supportive rods in hydrozoan cnidoblasts. The present study clearly demonstrates that structure and, possibly, function of an octocorallian cnidocyte is much simpler than that of a hydrozoan cnidocyte. On the other hand, cnidoblast migration, occurring in Hydrozoa as well in Octocorallia, turned out to be a much older phylogenetic character than was formerly believed.

  9. Einfluss von Methaneinträgen auf die Hydrochemie des Münsterländer Kiessandzuges

    NASA Astrophysics Data System (ADS)

    Strobel, M.; Wisotzky, F.

    2009-03-01

    The Münsterländer Kiessandzug, a Quaternary trench structure, forms an important groundwater reservoir and is of great importance for the regional drinking water supply in north-west Germany (“Münsterland”). Since 2004, the Ruhr-University Bochum has been investigating the Aldruper Mark, evaluating the quantitative and qualitative potential for drinking water abstraction in the area. Due to intensive agricultural utilisation, a high nitrate influx into groundwater is expected. Therefore, this study was focused on contamination of groundwater with nitrate as well as on the nitrate degradation capacity of the sediments. However, present analyses show low nitrate concentrations and a reductive groundwater environment. To find the causes of these reducing conditions, it is necessary to examine the geological and hydrochemical situation with respect to the environment and the substratum of the investigated area: the MünsterländerCretaceous basin is underlain by Carboniferous sand- and mudstones which are degasing methane to some extent. This methane was detected in deep observation wells in the second aquifer of the Münsterländer Kiessandzug. In its central area, low concentrations of nitrate as well as low sulphate concentrations and positive δ34Ssulfate-isotope data indicate active sulphate reduction is occurring in the groundwater. Furthermore, a corresponding sulphide content was found in these Quaternary soils (“secondary pyrite”). An input of methane in the aquifer is discussed as a possible reason for sulphate reduction in the deep aquifer.

  10. The astronomical instruments of Gottfried Kirch (German Title: Die astronomischen Instrumente von Gottfried Kirch)

    NASA Astrophysics Data System (ADS)

    Herbst, Klaus-Dieter

    The development of the instrumental equipment of Gottfried Kirch is analyzed in three sections: (1) from 1663 to 1681 (Kirch becomes famous as the discoverer of comet 1680), (2) in the 1680s and 1690s, (3) from 1700 onward (Kirch becomes Royal astronomer in Berlin). The evaluation of sources indicates that Kirch decisively improved his collection of astronomical instruments. In the following two decades, he acquired 16 telescopes up to 28 feet focal length, and a few smaller measuring instruments (among them several screw micrometers, an instrument invented by him). He used a 1-foot brass quadrant for time determination. With this equipment, Kirch belonged, in 1680/90, to the well-equipped astronomers. He was only lacking the major instruments for the measurement of angles, which were installed at the Royal observatories in Greenwich, Paris and Copenhagen and in private observatories in Gdansk and Nuremberg. Around 1700, the quality of his instruments was not sufficient any more to keep up scientifically with the best ones. Finally it is shown to what extent Kirch constructed or bought telescopes for himself or for other astronomers.

  11. Die Makrofauna und ihre Verteilung im Nordost-Felswatt von Helgoland

    NASA Astrophysics Data System (ADS)

    Janke, Klaus

    1986-03-01

    The macrofauna and its distribution in the sheltered, rocky intertidal zone of Helgoland (North Sea) was studied at 9 vertically and/or morphologically different stations from March to September in 1984. Seasonal variations in the communities were described based on each species' “conspicuousness”. A total of 172 species was found. The macrofauna shows a zoned pattern, but also the different substrata, for example, affect its distribution. The number of species increases from the upper intertidal to the upper sublittoral zone from 23 to 133 species. The upper intertidal is characterized by Littorina saxatilis, Chaetogrammarus marinus and Hyale nilssonii. Typical and abundant species of the middle and lower intertidal are Flustrellidra hispida, Littorina mariae/obtusata, Littorina littorea, Mytilus edulis and Spirorbis spirorbis. The upper sublittoral zone is characterized by Gibbula cineraria and increasing species numbers of Bryozoa, Nemertini and Opisthobranchia. Only few species (e.g. Dynamena pumila, Laomedea flexuosa, Polydora ciliata, Fabricia sabella, Jaera albifrons, Carcinus maenas) occur in the entire intertidal zone. In comparison to other very sheltered shores in Great Britain, which are also dominated by Fucaceae, the macrofauna in the Helgoland intertidal zone lacks several littoral species, such as Patella spp., Monodonta lineata, Gibbula umbilicalis, Littorina neritoides, Chthamalus spp., whereas Littorina littorea and Gibbula cineraria are highly abundant.

  12. Die Cnidogenese der Octocorallia (Anthozoa, Cnidaria): I. Sekretionund Differenzierung von Kapsel und Schlauch

    NASA Astrophysics Data System (ADS)

    Schmidt, H.

    1981-12-01

    The ultrastructural differentiation of capsule and its relation to tube development is described in several Octocorallia species (Alcyonaria: Alcyonium digitatum, Parerythropodium coralloides, Cornularia cornucopiae, Paralcyonium elegans; Pennatularia: Pteroeides spinosum, Veretillum cynomorium; Gorgonaria: Pseudopterogorgia aerosa), all of which have only one type nematocyst. In the Octocorallia, capsule and tube are secreted successively by the Golgi apparatus associated with a primary centriolar complex. During the secretion of the external tube, the outer capsular wall (sclera) is structurally differentiated; inside the capsule the material of the inner capsular wall is separated from the later capsular content (matrix). The primary wall differentiation enables the capsules to “grow” after capsular secretion has been completed. Following tube secretion, the external tube is completely transferred into the capsule, without the tube wall being transformed into capsular wall, as previously suggested (Westfall, 1966; Ivester, 1977). During early invagination of the tube wall, the coarse, granulated matrix of the external tube is transferred into the internal tube. From this material the spines are developed, which are observed before the tube is completely transferred into the capsule. By a secondary wall differentiation the previously structureless inner capsular wall changes to a complex structure, extending again the capsule, thus mixing the capsular content and enabling the tube to shift to a position, which corresponds with that of mature capsules. These observations demonstrate for the first time the differentiation of the capsule and its close relationship to the differentiation of the tube in nematocysts of Octocorallia.

  13. [Biomaterials in cochlear implants].

    PubMed

    Stöver, T; Lenarz, T

    2009-05-01

    Cochlear implants (CI) represent the "gold standard" for the treatment of congenitally deaf children and postlingually deafened adults. Thus, cochlear implantation is a success story of new bionic prosthesis development. Owing to routine application of cochlear implants in adults but also in very young children (below the age of one), high demands are placed on the implants. This is especially true for biocompatibility aspects of surface materials of implant parts which are in contact with the human body. In addition, there are various mechanical requirements which certain components of the implants must fulfil, such as flexibility of the electrode array and mechanical resistance of the implant housing. Due to the close contact of the implant to the middle ear mucosa and because the electrode array is positioned in the perilymphatic space via cochleostomy, there is a potential risk of bacterial transferral along the electrode array into the cochlea. Various requirements that have to be fulfilled by cochlear implants, such as biocompatibility, electrode micromechanics, and although a very high level of technical standards has been carried out there is still demand for the improvement of implants as well as of the materials used for manufacturing, ultimately leading to increased implant performance. General considerations of material aspects related to cochlear implants as well as potential future perspectives of implant development will be discussed.

  14. Breast Implants: Saline vs. Silicone

    MedlinePlus

    ... to women of any age for breast reconstruction. Silicone breast implants Silicone implants are pre-filled with ... likely be inserted at the same time. Ruptured silicone implant If a silicone breast implant ruptures, you ...

  15. Childhood Picture of Dr. von Braun

    NASA Technical Reports Server (NTRS)

    1912-01-01

    This is a childhood picture of Dr. von Braun (center) with his brothers. Dr. Wernher von Braun was born in Wirsitz, Germany, March 23, 1912. His childhood dreams of marned space flight were fulfilled when giant Saturn rockets, developed under his direction at NASA's Marshall Space Flight Center, boosted the manned Apollo spacecraft to the Moon. His life was dedicated to expanding man's knowledge through the exploration of space.

  16. Dr. von Braun With Management Team

    NASA Technical Reports Server (NTRS)

    1961-01-01

    Dr. von Braun is shown in this photograph, which was probably taken in the early 1960s, with members of his management team. Pictured from left to right are, Werner Kuers, Director of the Manufacturing Engineering Division; Dr. Walter Haeussermarn, Director of the Astrionics Division; Dr. William Mrazek, Propulsion and Vehicle Engineering Division; Dr. von Braun; Dieter Grau, Director of the Quality Assurance Division; Dr. Oswald Lange, Director of the Saturn Systems Office; and Erich Neubert , Associate Deputy Director for Research and Development.

  17. Implants for lucky few

    NASA Astrophysics Data System (ADS)

    Brandon, David

    2011-08-01

    In his article "Vision of beauty" (May pp22-27), Richard Taylor points the way to fractal design for retinal implants and makes an enthusiastic case for incorporating such features into the next generation of such implants.

  18. The thermal fatigue resistance of H-13 Die Steel for aluminum die casting dies

    NASA Technical Reports Server (NTRS)

    1982-01-01

    The effects of welding, five selected surface coatings, and stress relieving on the thermal fatigue resistance of H-13 Die Steel for aluminum die casting dies were studied using eleven thermal fatigue specimens. Stress relieving was conducted after each 5,000 cycle interval at 1050 F for three hours. Four thermal fatigue specimens were welded with H-13 or maraging steel welding rods at ambient and elevated temperatures and subsequently, subjected to different post-weld heat treatments. Crack patterns were examined at 5,000, 10,000, and 15,000 cycles. The thermal fatigue resistance is expressed by two crack parameters which are the average maximum crack and the average cracked area. The results indicate that a significant improvement in thermal fatigue resistance over the control was obtained from the stress-relieving treatment. Small improvements were obtained from the H-13 welded specimens and from a salt bath nitrogen and carbon-surface treatment. The other surface treatments and welded specimens either did not affect or had a detrimental influence on the thermal fatigue properties of the H-13 die steel.

  19. Vergleich von rekombinanten Vaccinia- und DNA-Vektoren zur Tumorimmuntherapie im C57BL/6-Mausmodell

    NASA Astrophysics Data System (ADS)

    Johnen, Heiko

    2002-10-01

    In der vorliegenden Arbeit wurden Tumorimpfstoffe auf der Basis des Plasmid-Vektors pCI, modified vaccinia virus Ankara (MVA) und MVA-infizierten dendritischen Zellen entwickelt und durch Sequenzierung, Western blotting und durchflußzytometrische Analyse überprüft. Die in vivo Wirksamkeit der Vakzinen wurde in verschiedenen Tumormodellen in C57BL/6 Mäusen verglichen. Die auf dem eukaryotischen Expressionsvektor pCI basierende DNA-Vakzinierung induzierte einen sehr wirksamen, antigenspezifischen und langfristigen Schutz vor Muzin, CEA oder beta-Galactosidase exprimierenden Tumoren. Eine MVA-Vakzinierung bietet in den in dieser Arbeit durchgeführten Tumormodellen keinen signifikanten Schutz vor Muzin oder beta-Galactosidase exprimierenden Tumoren. Sowohl humane, als auch murine in vitro generierte dendritische Zellen lassen sich mit MVA – im Vergleich zu anderen viralen Vektoren – sehr gut infizieren. Die Expressionsrate der eingefügten Gene ist aber gering im Vergleich zur Expression in permissiven Wirtszellen des Virus (embryonale Hühnerfibroblasten). Es konnte gezeigt werden, daß eine MVA-Infektion dendritischer Zellen ähnliche Auswirkungen auf den Reifezustand humaner und muriner dendritischer Zellen hat, wie eine Infektion mit replikationskompetenten Vakzinia-Stämmen, und außerdem die Hochregulation von CD40 während der terminalen Reifung von murinen dendritischen Zellen inhibiert wird. Die während der langfristigen in vitro Kultur auf CEF-Zellen entstandenen Deletionen im MVA Genom führten zu einer starken Attenuierung und dem Verlust einiger Gene, die immunmodulatorische Proteine kodieren, jedoch nicht zu einer Verminderung des zytopathischen Effekts in dendritischen Zellen. Die geringe Expressionsrate und die beobachtete Inhibition der Expression kostimulatorischer Moleküle auf dendritischen Zellen kann für eine wenig effektive Induktion einer Immunantwort in MVA vakzinierten Tieren durch cross priming oder die direkte Infektion

  20. Implantable Heart Aid

    NASA Technical Reports Server (NTRS)

    1984-01-01

    CPI's human-implantable automatic implantable defibrillator (AID) is a heart assist system, derived from NASA's space circuitry technology, that can prevent erratic heart action known as arrhythmias. Implanted AID, consisting of microcomputer power source and two electrodes for sensing heart activity, recognizes onset of ventricular fibrillation (VF) and delivers corrective electrical countershock to restore rhythmic heartbeat.

  1. Influence of PEEK Coating on Hip Implant Stress Shielding: A Finite Element Analysis

    PubMed Central

    Anguiano-Sanchez, Jesica; Martinez-Romero, Oscar; Siller, Hector R.; Diaz-Elizondo, Jose A.; Flores-Villalba, Eduardo

    2016-01-01

    Stress shielding is a well-known failure factor in hip implants. This work proposes a design concept for hip implants, using a combination of metallic stem with a polymer coating (polyether ether ketone (PEEK)). The proposed design concept is simulated using titanium alloy stems and PEEK coatings with thicknesses varying from 100 to 400 μm. The Finite Element analysis of the cancellous bone surrounding the implant shows promising results. The effective von Mises stress increases between 81 and 92% for the complete volume of cancellous bone. When focusing on the proximal zone of the implant, the increased stress transmission to the cancellous bone reaches between 47 and 60%. This increment in load transferred to the bone can influence mineral bone loss due to stress shielding, minimizing such effect, and thus prolonging implant lifespan. PMID:27051460

  2. Should assisted dying be legalised?

    PubMed

    Frost, Thomas D G; Sinha, Devan; Gilbert, Barnabas J

    2014-01-15

    When an individual facing intractable pain is given an estimate of a few months to live, does hastening death become a viable and legitimate alternative for willing patients? Has the time come for physicians to do away with the traditional notion of healthcare as maintaining or improving physical and mental health, and instead accept their own limitations by facilitating death when requested? The Universities of Oxford and Cambridge held the 2013 Varsity Medical Debate on the motion "This House Would Legalise Assisted Dying". This article summarises the key arguments developed over the course of the debate. We will explore how assisted dying can affect both the patient and doctor; the nature of consent and limits of autonomy; the effects on society; the viability of a proposed model; and, perhaps most importantly, the potential need for the practice within our current medico-legal framework.

  3. Guide for extrusion dies eliminates straightening operation

    NASA Technical Reports Server (NTRS)

    Gyorgak, C. A.; Hoover, R. J.

    1964-01-01

    To prevent distortion of extruded metal, a guidance assembly is aligned with the die. As the metal emerges from the extrusion dies, it passes directly into the receiver and straightening tube system, and the completed extrusion is withdrawn.

  4. [Biology of von Willebrand factor].

    PubMed

    Girma, Jean-Pierre

    2006-01-01

    Von Willebrand factor (VWF) is a multimeric glycoprotein synthesized by megakaryocytes and endothelial cells. It is stored in platelets and endothelial cells and secreted towards subendothelium and plasma. VWF multimers consist of linear arrangements of identical subunits with a molecular weight of 270 kDa. The longest multimers reach more than 20 x 10(6) Da in storage granules. In the circulation, the multimer size is limited by the specific protease ADAMTS13. In primary hemostasis, VWF plays a key role as a molecular bridge in adhesion between platelets and subendothelium and between platelets during their aggregation. These functions, which involve the interaction with platelet glycoprotein lb, are mainly enhanced by VWF immobilization onto hydrophobic surfaces (collagen, cell membrane) and by high shear rates found in microcirculation and stenosed arteries. In these functions, the higher molecular weight forms are the most efficient. Under such hemodynamic conditions, proteolytic activity of ADAMTS13 is also optimal and limits the multimer size to about 15 x 10(6) Da as soon as their secretion. Thus ADAMTS13 appears as a key physiologic regulator of the VWF platelet functions. In the microcirculation, the lack of ADAMTS13 activity can result in the formation of VWF-rich platelet aggregates responsible for thrombotic thrombocytopenic purpura.

  5. Von Karman re-visited

    NASA Astrophysics Data System (ADS)

    McEligot, Donald M.; Nolan, Kevin P.; Walsh, Edmond J.

    2012-11-01

    A number of authors have presented extended versions of the integral momentum equation, allowing for perturbations or fluctuations in the boundary layer. ``Conventional wisdom'' is that these added terms can be neglected and one can apply the von Karman version directly. For two-dimensional turbulent boundary layers at high Reynolds numbers, experience shows this assumption to be reasonable. However, recent examination of entropy generation in bypass transition with zero pressure gradient shows a term for turbulence energy convection can be important in determining the energy dissipation coefficient [Walsh et al., JFE 2011]. The present study employs the direct numerical simulations of Zaki and Durbin [JFM 2006] for bypass transition with streamwise pressure gradients to quantify the additional normal stress term when estimating the skin friction coefficient via a momentum balance. It is found that this term becomes noticeable in the pre-transitional laminar boundary layer and can exceed forty per cent of Cf in the transition region. Thus, it should be included in such calculations. Partly supported by U. S. DoE EPSCoR office.

  6. Trends in Cochlear Implants

    PubMed Central

    Zeng, Fan-Gang

    2004-01-01

    More than 60,000 people worldwide use cochlear implants as a means to restore functional hearing. Although individual performance variability is still high, an average implant user can talk on the phone in a quiet environment. Cochlear-implant research has also matured as a field, as evidenced by the exponential growth in both the patient population and scientific publication. The present report examines current issues related to audiologic, clinical, engineering, anatomic, and physiologic aspects of cochlear implants, focusing on their psychophysical, speech, music, and cognitive performance. This report also forecasts clinical and research trends related to presurgical evaluation, fitting protocols, signal processing, and postsurgical rehabilitation in cochlear implants. Finally, a future landscape in amplification is presented that requires a unique, yet complementary, contribution from hearing aids, middle ear implants, and cochlear implants to achieve a total solution to the entire spectrum of hearing loss treatment and management. PMID:15247993

  7. Contoured Orifice for Silicon-Ribbon Die

    NASA Technical Reports Server (NTRS)

    Mackintosh, B. H.

    1985-01-01

    Die configuration encourages purity and stable growth. Contour of die orifice changes near ribbon edges. As result, silicon ribbon has nearly constant width and little carbon contamination. Die part of furnace being developed to produce high-quality, low-cost material for solar cells.

  8. Lethal Hemorrhage Caused by Aortoenteric Fistula Following Endovascular Stent Implantation

    SciTech Connect

    Kahlke, Volker; Brossmann, Joachim; Klomp, Hans-Juergen

    2002-06-15

    A 55-year-old women developed an aortointestinal fistula between the bifurcation of the aorta and the distal ileum following implantation of multiple endovascular stents into both common iliac arteries for treatment of aortoiliac occlusive disease. Ten months before the acute onset of the gastrointestinal hemorrhage two balloon-expandable steel stents had been implanted into both common iliac arteries. Due to restenosis and recurrent intermittent claudication, three balloon-expandable covered stents were implanted 4 months later on reintervention. The patient presented with abdominal pain and melena, and fell into hemorrhagic shock with signs of upper gastrointestinal bleeding. After transfer to our hospital, she again developed hemorrhagic shock with massive upper and lower gastrointestinal bleeding and died during emergency laparotomy. The development of aortoenteric fistulas following endovascular surgery/stent implantation is very rare and has to be considered in cases of acute gastrointestinal hemorrhage.

  9. Industrial applications of ion implantation into metal surfaces

    SciTech Connect

    Williams, J.M.

    1987-07-01

    The modern materials processing technique, ion implantation, has intriguing and attractive features that stimulate the imaginations of scientists and technologists. Success of the technique for introducing dopants into semiconductors has resulted in a stable and growing infrastructure of capital equipment and skills for use of the technique in the economy. Attention has turned to possible use of ion implantation for modification of nearly all surface related properties of materials - optical, chemical and corrosive, tribological, and several others. This presentation provides an introduction to fundamental aspects of equipment, technique, and materials science of ion implantation. Practical and economic factors pertaining to the technology are discussed. Applications and potential applications are surveyed. There are already available a number of ion-implanted products, including ball-and-roller bearings and races, punches-and-dies, injection screws for plastics molding, etc., of potential interest to the machine tool industry.

  10. Biomechanical Effects of Platform Switching in Two Different Implant Systems: A Three-Dimensional Finite Element Analysis

    PubMed Central

    Sahabi, Mahasti; Adibrad, Mehdi; Mirhashemi, Fatemeh Sadat; Habibzadeh, Sareh

    2013-01-01

    Objectives: The purpose of this study was to determine the influence of platform switching on stress distribution of two different implant systems using three-dimensional (3D) finite element models. Materials and Methods: Six 3D finite element models were created to replicate two different implant systems with peri-implant bone tissue, in which six different implant-abutment configurations were represented: model XiVE-a: 3.8-mm-diameter implant and 3.8-mm-diameter abutment; model XiVE-b (platform-switching model): 4.5-mm-diameter implant and 3.8-mm-diameter abutment; model XiVE-c: 4.5-mm-diameter implant and 4.5-mm-diameter abutment; model 3i-a: 4.0-mm-diameter implant and 4.1-mm-diameter abutment; model 3i-b (platform-switching model): 5.0-mm-diameter implant and 4.1-mm-diameter abutment; model 3i-c: 5.0-mm-diameter implant and 5.0-mm-diameter abutment. vertical and oblique loads of 100 were applied to all models. Results: While the pattern of stress distribution was similar for both loading situations, oblique loading resulted in higher intensity and greater distribution of stress than axial loading in both cortical bone and implant-abutment- interface. Stress distribution at peri-implant bone was almost identical with similar magnitudes for all six models. In both implant systems, platform-switching models demonstrated lower maximum von Mises stress in cortical bone than conventional models. However, in both implant systems and under both loading situations, platform-switching models showed higher stresses at the implant-abutment interface than conventional models. Conclusion: In both implant systems, platform switching design reduced the stress concentration in the crestal bone and shifted it towards the area of implant-abutment interface. PMID:24396353

  11. An MRI Von Economo - Koskinas atlas.

    PubMed

    Scholtens, Lianne H; de Reus, Marcel A; de Lange, Siemon C; Schmidt, Ruben; van den Heuvel, Martijn P

    2016-12-28

    The cerebral cortex displays substantial variation in cellular architecture, a regional patterning that has been of great interest to anatomists for centuries. In 1925, Constantin von Economo and George Koskinas published a detailed atlas of the human cerebral cortex, describing a cytoarchitectonic division of the cortical mantle into over 40 distinct areas. Von Economo and Koskinas accompanied their seminal work with large photomicrographic plates of their histological slides, together with tables containing for each described region detailed morphological layer-specific information on neuronal count, neuron size and thickness of the cortical mantle. Here, we aimed to make this legacy data accessible and relatable to in vivo neuroimaging data by constructing a digital Von Economo - Koskinas atlas compatible with the widely used FreeSurfer software suite. In this technical note we describe the procedures used for manual segmentation of the Von Economo - Koskinas atlas onto individual T1 scans and the subsequent construction of the digital atlas. We provide the files needed to run the atlas on new FreeSurfer data, together with some simple code of how to apply the atlas to T1 scans within the FreeSurfer software suite. The digital Von Economo - Koskinas atlas is easily applicable to modern day anatomical MRI data and is made publicly available online.

  12. Evolution of the mandibular mesh implant.

    PubMed

    Salyer, K E; Johns, D F; Holmes, R E; Layton, J G

    1977-07-01

    Between 1960 and 1972, the Dallas Veterans Administration Hospital Maxillofacial Research Laboratory developed and made over 150 cast-mesh implants. Successive designs were ovoid, circular, and double-lumened in cross section to improve implant strength, surface area for bioattachment, and adjustability. Sleeves, collars, and bows were employed in the assembly of these implants, with an acrylic condylar head attached when indicated. In 1972, our laboratory developed a mandibular mesh tray, cast in one piece on a single sprue, with preservation of the vertically adjustable ramus. Stainless steel replaced Vitallium because of its greater malleability. Essentially, a lost-wax technique is used to cast the mesh tray. The model of a mandibular segment is duplicated as a refractory model. Mesh wax, made in our own custom-made die, is adapted to the refractory model. The unit is then sprued and invested. The wax is fired our of the mold in a gas furnace. Casting is done by the transferral of molten stainless steel from the crucible to the mold by centrifugal force in an electro-induction casting machine. Other mesh implants that have been developed are made from wire mesh, Dacron mesh, cast Ticonium, and hydroformed titanium.

  13. Sulfation of von Willebrand factor

    SciTech Connect

    Carew, J.A.; Browning, P.J.; Lynch, D.C. )

    1990-12-15

    von Willebrand factor (vWF) is a multimeric adhesive glycoprotein essential for normal hemostasis. We have discovered that cultured human umbilical vein endothelial cells incorporate inorganic sulfate into vWF. Following immunoisolation and analysis by polyacrylamide or agarose gel electrophoresis, metabolically labeled vWF was found to have incorporated (35S)-sulfate into all secreted multimer species. The time course of incorporation shows that sulfation occurs late in the biosynthesis of vWF, near the point at which multimerization occurs. Quantitative analysis suggests the presence, on average, of one molecule of sulfate per mature vWF subunit. Virtually all the detectable sulfate is released from the mature vWF subunit by treatment with endoglycosidases that remove asparagine-linked carbohydrates. Sulfated carbohydrate was localized first to the N-terminal half of the mature subunit (amino acids 1 through 1,365) by partial proteolytic digestion with protease V8; and subsequently to a smaller fragment within this region (amino acids 273 through 511) by sequential digestions with protease V8 and trypsin. Thus, the carbohydrate at asparagine 384 and/or 468 appears to be the site of sulfate modification. Sodium chlorate, an inhibitor of adenosine triphosphate-sulfurylase, blocks sulfation of vWF without affecting either the ability of vWF to assemble into high molecular weight multimers or the ability of vWF multimers to enter Weible-Palade bodies. The stability of vWF multimers in the presence of an endothelial cell monolayer also was unaffected by the sulfation state. Additionally, we have found that the cleaved propeptide of vWF is sulfated on asparagine-linked carbohydrate.

  14. Dr. Wernher Von Braun with Dr. Christian Barnard.

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Dr. Christian Barnard Tours Marshall Space Flight Center. Shown in Dr. Von Braun's office are (left to right): Dr. Ernst Sthulinger, a representative from General Electric, Dr. Wernher Von Braun, Dr. Christian Barnard, and Dr. Eberhard Rees.

  15. Die Welt des Herrn Kuhn

    NASA Astrophysics Data System (ADS)

    Kern, Daniela

    Eines Morgens erwachte Herr Kuhn fröstelnd und staunte darüber, dass es in seinerWohnung eiskalt war. Dennoch quälte er sich aus seiner kuscheligen Bettdecke heraus und schlurfte ins Bad. "Hoffentlich wird wenigstens das Wasser warm", dachte er sich, als er den Wasserhahn betätigte - aber es kam nicht nur kein warmesWasser, außer einem unheilvollen Gluckser kam gar nichts aus der Leitung. "Dann werde ich wohl mal den Klempner anrufen", sprach er sich leise in den Bart und griff zu seinem Handy - doch das Netz war tot! Herr Kuhn begann nun, sich ernsthaft Sorgen zu machen, "Oje, was ist denn heute nur los? Ist irgendetwas Schlimmes passiert?" Um einen besseren Überblick über die Lage zu bekommen und sich austauschen zu können, brannte er nun förmlich darauf, rauszugehen und zur Arbeit zu fahren. An anderen Tagen, die er frisch geduscht und mit Kaffee und Marmeladen-Brot begann, war er selten so motiviert. So ging er also nun mit leerem Magen aus dem Haus. Hätte er den Versuch unternommen, sein tägliches Marmeladenbrot zuzubereiten, und dafür den Kühlschrank geöffnet, um das Marmeladenglas herauszunehmen, wäre ihm aufgefallen, dass auch die Stromversorgung Störungen unterworfen war, unschön zu erkennen an den ersten grünen, felligen Inseln auf seinem Lieblingskäse.

  16. Importance of diameter-to-length ratio in selecting dental implants: a methodological finite element study.

    PubMed

    Demenko, V; Linetskiy, I; Nesvit, K; Hubalkova, H; Nesvit, V; Shevchenko, A

    2014-01-01

    Implant dimensions greatly influence load transfer characteristics and the lifetime of a dental system. Excessive stresses at peri-implant area may result in bone failure. Finding the critical point at the implant-bone interface and evaluating the influence of implant diameter-to-length ratio on adjacent bone stresses makes it possible to select implant dimensions. For this, different cylindrical implants were numerically analysed using geometrical models generated from computed tomography images of mandible with osseointegrated implants. All materials were assumed to be linearly elastic and isotropic. Masticatory load was applied in its natural direction, oblique to occlusal plane. Maximum von Mises stresses were located around the implant neck at the critical point of its intersection with the plane of loading and were functions of implant diameter-to-length ratio. It was demonstrated that there exists a certain spectrum of diameter-to-length ratios, which will keep maximum bone stresses at a preset level chosen in accordance with patient's bone strength.

  17. Liouville-von Neumann molecular dynamics

    NASA Astrophysics Data System (ADS)

    Jakowski, Jacek; Morokuma, Keiji

    2009-06-01

    We present a novel first principles molecular dynamics scheme, called Liouville-von Neumann molecular dynamics, based on Liouville-von Neumann equation for density matrices propagation and Magnus expansion of the time-evolution operator. The scheme combines formally accurate quantum propagation of electrons represented via density matrices and a classical propagation of nuclei. The method requires a few iterations per each time step where the Fock operator is formed and von Neumann equation is integrated. The algorithm (a) is free of constraint and fictitious parameters, (b) avoids diagonalization of the Fock operator, and (c) can be used in the case of fractional occupation as in metallic systems. The algorithm is very stable, and has a very good conservation of energy even in cases when a good quality conventional Born-Oppenheimer molecular dynamics trajectories is difficult to obtain. Test simulations include initial phase of fullerene formation from gaseous C2 and retinal system.

  18. State of the art: von Willebrand disease.

    PubMed

    James, A H; Eikenboom, J; Federici, A B

    2016-07-01

    The State of the Art in von Willebrand disease (VWD) has been impacted not only by discoveries in the field of haemostasis, but also by changes in practice in other fields. The development of bleeding assessment tools has led to the clarification of bleeding symptoms and phenotype in VWD. New discoveries in the biology and genetics of von Willebrand factor (VWF) are challenging our existing diagnostics and classification(s). An improved understanding of reproductive physiology and the pathology of VWD along with changing obstetric, gynaecologic and haemostatic therapies necessitate an evolving response to the care of women with VWD. The survival of patients with autoimmune disease, malignancies and congenital heart disease along with increasing use of circulatory support devices and extracorporeal membrane oxygenation is increasing the prevalence of acquired von Willebrand syndrome. In each of these challenges, there are opportunities to improve the care of our patients with VWD.

  19. Treatment of the acquired von Willebrand syndrome.

    PubMed

    Budde, Ulrich; Scheppenheim, Sonja; Dittmer, Rita

    2015-12-01

    Acquired von Willebrand syndrome (aVWS) accounts for 22% of patients with abnormal von Willebrand factor. Most patients with known pathophysiological mechanisms suffer from cardiovascular, myeloproliferative and lymphoproliferative disorders. Less frequent associations are of autoimmune origin, due to hyperfibrinolysis, adsorption to tumor cells, reduced synthesis and prolonged circulation. The mechanisms leading to aVWS is hitherto not known in patients with liver and kidney diseases, drug use, glycogen storage disease, virus infections and at least 18 other disease entities. Diagnosis is complicated by the battery of tests needed, and their inherent rather low sensitivity and specificity for aVWS. Thus, even in acute bleeding situations it may take days until a firm diagnosis is settled and specific therapies can be initiated. The main aim is to shed more light onto this, compared with inherited von Willebrand disease, rare disease which affects at least 2-3% of the older population.

  20. Bildung von Metall-Metall-Mischkristallen mittels Ionenstrahl-induzierter Mischung

    NASA Astrophysics Data System (ADS)

    Hohmuth, K.; Rauschenbach, B.

    Die Ionenstrahl-induzierte Mischung der Dünnfilm-Systeme CuAg und CrFe nach Bestrahlung mit energiereichen Xe-und Ar-Ionen bei Raumtemperatur wurde untersucht. Die Präparation der Multischicht-Systeme, die aus dünnen Filmen der beiden Elemente bestehen, erfolgt durch Aufdampfen auf inerte Substrate. Die bestrahlten Systeme wurden mit Hochspannungs-Elektronenmikroskopie, Feinbereichsbeugung und Rutherford-Rückstreuung analysiert. Beim System CuAg entstehen über den gesamten Konzentrationsbereich metastabile Mischkristallphasen. Die Ionenstrahl-induzierte Mischung des CuAu-Systems führt nach einer thermischen Nachbehandlung zur Bildung von Überstrukturen. Durch Bestrahlung des CrFe-Systems werden CrFe-Martensit und eine '-CrFe Hochdruckphase gebildet. Die '-CrFe-Ausscheidungen sind senrecht zum Ionenstrahl und senkrecht zueinander orientiert.Translated AbstractFormation of Mixed Crystals from Two Metals by Ion Beam MixingIon-beam mixing of thin film systems of CuAg, CuAu and CrFe was studied using irradiation with energetic Xe- and Ar-ions at room temperature. Multi-layered samples consisting of thin layers of two elements were prepared by evaporating on inert substrates. The irradiated systems were investigated using high voltage electron microscopy, selected area diffraction and Rutherford backscattering. Metastable solid solutions of CuAg are formed across the entire composition range. After ion-beam mixing and thermal treatment of the CuAu system superlattices have been found. CrFe-martensite and a '-CrFe highpressure phase are formed by irradiation of CrFe systems. The δ'-CrFe precipitations are oriented perpendicular to the ion beam and perpendicular to each other.

  1. Biosynthesis, processing and secretion of von Willebrand factor: biological implications.

    PubMed

    de Wit, T R; van Mourik, J A

    2001-06-01

    von Willebrand factor is a multimeric plasma glycoprotein that is required for normal haemostasis. von Willebrand factor is synthesized by endothelial cells and megakaryocytes, and originates from its precursor pro-von Willebrand factor. The endoproteolytic processing of pro-von Willebrand factor results in mature von Willebrand factor and von Willebrand factor propeptide (also known as von Willebrand Ag II). In endothelial cells, the propeptide controls the polymerization and subsequent targeting of von Willebrand factor to the storage vesicles, the so-called Weibel-Palade bodies. Upon stimulation of the endothelial cells, the Weibel-Palade bodies are translocated to the plasma membrane of the cell, and mature von Willebrand factor and its propeptide are co-secreted. After release, these polypeptides have divergent fates and serve different biological functions. Mature von Willebrand factor both controls platelet adhesion and aggregation at sites of vascular injury and acts as a chaperone protein for coagulation factor VIII. The von Willebrand factor propeptide may serve a role in modulating inflammatory processes. This still growing body of information indicates that the biological function of the von Willebrand factor gene product is more diverse than was previously thought.

  2. [Cochlear implant in adults].

    PubMed

    Bouccara, D; Mosnier, I; Bernardeschi, D; Ferrary, E; Sterkers, O

    2012-03-01

    Cochlear implant in adults is a procedure, dedicated to rehabilitate severe to profound hearing loss. Because of technological progresses and their applications for signal strategies, new devices can improve hearing, even in noise conditions. Binaural stimulation, cochlear implant and hearing aid or bilateral cochlear implants are the best opportunities to access to better level of comprehension in all conditions and space localisation. By now minimally invasive surgery is possible to preserve residual hearing and use a double stimulation modality for the same ear: electrical for high frequencies and acoustic for low frequencies. In several conditions, cochlear implant is not possible due to cochlear nerve tumour or major malformations of the inner ear. In these cases, a brainstem implantation can be considered. Clinical data demonstrate that improvement in daily communication, for both cochlear and brainstem implants, is correlated with cerebral activation of auditory cortex.

  3. [Research advance in von Willebrand factor].

    PubMed

    Li, Xue-Mei; Jiang, Miao; Zhao, Yi-Ming

    2013-06-01

    von Willebrand factor (vWF) is a multimeric glycoprotein exclusively synthesized in endothelial cells and megakaryocytes. It plays important roles in the primary and secondary haemostasis. Deficiency or dysfunction of vWF may cause von Willebrand disease (vWD), and overexpression of vWF may cause thrombosis. Making an intensive study on vWF will help us to understand the pathophysiology, diagnosis and treatment of vWF-related diseases, such as vWD, TTP, venous thrombosis, stroke, and so on. In this article, the regulation of vWF activity and its relation with diseases mentioned above are reviewed.

  4. Laboratory diagnosis of von Willebrand disease.

    PubMed

    Roberts, J C; Flood, V H

    2015-05-01

    Von Willebrand disease (VWD) is considered the most common inherited bleeding disorder and may also be the most difficult to diagnose. Clinical symptoms of VWD include predominantly mild mucosal bleeding; surgical bleeding may occur with specific challenges and joint bleeding can occur in the most severe forms. A family history either of diagnosed VWD or of bleeding symptoms is typically present. Laboratory diagnosis requires a series of assays of von Willebrand factor (VWF) quantity and function, and factor VIII activity, with no single straightforward diagnostic test available to either confirm or exclude the diagnosis. Newer assays of VWF function are becoming more available and useful in determining the laboratory diagnosis of VWD.

  5. Manual for the psychotherapeutic treatment of acute and post-traumatic stress disorders following multiple shocks from implantable cardioverter defibrillator (ICD).

    PubMed

    Jordan, Jochen; Titscher, Georg; Peregrinova, Ludmila; Kirsch, Holger

    2013-01-01

    Hintergrund: Angesichts der ständig steigenden Zahl implantierter Defibrillatoren steigt auch die Zahl der Menschen, die sog. Mehrfachschocks erleben. Fünf oder mehr Schocks (adäquate oder inadäquate) innerhalb von 12 Monaten oder drei und mehr Schocks innerhalb einer Episode (24 Stunden) führen nach derzeitigem Kenntnisstand zu einem Anstieg von psychopathologischen Symptomen (Angststörung, Panikstörung, Anpassungsstörung und posttraumatische Belastungsstörung). Unbehandelt führt dies zu einer Chronifizierung bei niedriger Spontanremission und zu einer Erhöhung der Morbidität und Mortalität. Es gibt nur wenige Publikationen zur psychotherapeutischen Behandlung dieser PatientInnen.Ziel: Ziel der Studie war die Entwicklung und Erprobung einer multimodalen psychotherapeutischen Intervention für Menschen nach Defi-Mehrfachschocks und einer Anpassungsstörung oder posttraumatischen Belastungsstörung.Design: Es handelt sich um eine Machbarkeitsstudie: PatientInnen wurden in einem naturalistischen Design (unausgewählt, ohne Randomisierung und ohne Kontrollgruppe) stationär behandelt. Der Einschluss der PatientInnen erfolgte zwischen März 2007 bis März 2010. Die Studie bestand aus zwei Phasen. In der ersten Phase der Pilotstudie entwickelten und erprobten wir verschiedene Behandlungskomponenten und die Behandlungsdosis variierte. In der zweiten Phase (Follow-up-Studie) fand eine postalische Nachuntersuchung mittels Fragebögen statt. Der Nachbefragungszeitraum variierte zwischen 12 und 30 Monaten.Stichprobe: Im Untersuchungszeitraum wurden 31 PatientInnen in die Klinik für Psychokardiologie der Kerckhoff Klinik überwiesen. Die von uns behandelte Gruppe bestand am Ende aus 22 Personen, die eine Anpassungsstörung oder posttraumatische Störung hatten und die in der Lage und Willens waren, an der Studie teilzunehmen. In die Follow-up-Studie konnten wir 18 von diesen 22 PatientInnen einschließen.Methoden: Zu Beginn und am Ende der station

  6. Implant treatment planning considerations.

    PubMed

    Kao, Richard T

    2008-04-01

    As dental implants become a more accepted treatment modality, there is a need for all parties involved with implant dentistry to be familiar with various treatment planning issues. Though the success can be highly rewarding, failure to forecast treatment planning issues can result in an increase of surgical needs, surgical cost, and even case failure. In this issue, the focus is on implant treatment planning considerations.

  7. Ein Unscented Kalman Filter zur Schätzung von Schaltungsnichtidealitäten eines zeitkontinuierlichen Sigma-Delta Wandlers mit impliziter Dezimation

    NASA Astrophysics Data System (ADS)

    Buhmann, A.; Keller, M.; Maurer, M.; Ortmanns, M.; Manoli, Y.

    2008-05-01

    Nichtidealitäten einer Schaltung, wie z.B. nicht ideale Charakteristik des Operationsverstärkers und Streuungen in den Filterkoeffizienten, sind dahingehend bekannt die Effizienz von zeitkontinuierlichen Sigma-Delta Wandlern in drastischer Weise zu reduzieren. Daher stellt diese Veröffentlichung eine mögliche Methode vor, um die genannten Nichtidealitäten durch eine Schätzung mit Hilfe eines Unscented Kalman Filters zu bestimmen und in einem möglichen weiteren Schritt zu korrigieren. Des Weiteren kann durch eine leichte Modifikation des vorgestellten Algorithmus auch gleichzeitig eine implizite Dezimation des Ausgangssignals durchgeführt werden. Hierdurch wird die Gesamteffizienz des vorgestellten Ansatzes gesteigert, da kein zusätzlicher Dezimationsfilter mehr benötigt wird. Simulationsergebnisse des Filteralgorithmus zeigen die prinzipielle Funktion des Algorithmus.

  8. Osseointegrated implant prosthodontics.

    PubMed

    Rogoff, G S

    1992-06-01

    This review covers recent literature on prosthodontic aspects of osseointegrated implants. Long-term prognosis, diagnosis and treatment planning, and clinical impression techniques and fabrication technology are discussed.

  9. Evaluation of permanent die coatings to improve the wear resistance of die casting dies. Final project report, January 1, 1995--April 30, 1997

    SciTech Connect

    Shivpuri, R.

    1997-09-18

    Die Casting dies are subject to severe service conditions during the die casting operation. While these severe conditions are necessary to achieve high production rates, they cause the dies which are commonly made of H13 die steel, to suffer frequent failures. The major die failure mechanisms are erosion or washout, Heat checking, soldering and corrosion. Due to their geometrical complexity, die casting dies are very expensive (some dies cost over a million dollars), and thus a large number of parts have to be produced by a die, to justify this cost and leverage the advantages of the die casting process (high production rates, low manpower costs). A potential increase in the die service life, thus has a significant impact on the economics of the die; casting operation. There are many ways to extend die life: developing new wear resistant die materials, developing new surface treatments including coatings, improving heat treatment of existing H13 dies, using better lubricants that can protect the die material, or modifying the die geometry and process parameters to reduce the intensity of wear. Of these the use of coatings to improve the wear resistance of the die surface has shown a lot of promise. Consequently, use of coatings in the die casting industry and their wide use to decrease die wear can improve significantly the productivity of shop operations resulting in large savings in material and energy usage.

  10. Stress Distribution Around Single Short Dental Implants: A Finite Element Study.

    PubMed

    Vidya Bhat, S; Premkumar, Priyanka; Kamalakanth Shenoy, K

    2014-12-01

    Bone height restrictions are more common in the posterior regions of the mandible, because of either bone resorption resulting from tooth loss or even anatomic limitations, such as the position of the inferior alveolar nerve. In situations where adequate bone height is not available in the posterior mandible region, smaller lengths of implants may have to be used but it has been reported that the use of long implants (length ≥10 mm) is a positive factor in osseointegration and authors have reported failures with short implants. Hence knowledge about the stress generated on the bone with different lengths of implants needs scientific evaluation. The purpose of this study was to compare and evaluate the influence of different lengths of implants on stress upon bone in mandibular posterior area. A 3 D finite element model was made of the posterior mandible using the details from a CT scan, using computer software (ANSYS 12). Four simulated implants with lengths 6 mm, 8 mm, 10 mm and 13 mm were placed in the centre of the bone. A static vertical force of 250 N and a static horizontal force of 100 N were applied. The stress generated in the cortical and cancellous bone around the implant were recorded and evaluated with the help of ANSYS. In this study, Von Mises stress on a 6 mm implant under a static vertical load of 250 N appeared to be almost in the same range of 8 and 10 mm implant which were more as compared to 13 mm implant. Von Mises stress on a 6mm implant under a static horizontal load of 100 N appeared to be less when compared to 8, 10 and 13 mm implants. From the results obtained it may be inferred that under static horizontal loading conditions, shorter implants receive lesser load and thus may tend to transfer more stresses to the surrounding bone. While under static vertical loading the shorter implants bear more loads and comparatively transmit lesser load to the surrounding bone.

  11. Die singulation method and package formed thereby

    DOEpatents

    Anderson, Robert C [Tucson, AZ; Shul, Randy J [Albuquerque, NM; Clews, Peggy J [Tijeras, NM; Baker, Michael S [Albuquerque, NM; De Boer, Maarten P [Albuquerque, NM

    2012-08-07

    A method is disclosed for singulating die from a substrate having a sacrificial layer and one or more device layers, with a retainer being formed in the device layer(s) and anchored to the substrate. Deep Reactive Ion Etching (DRIE) etching of a trench through the substrate from the bottom side defines a shape for each die. A handle wafer is then attached to the bottom side of the substrate, and the sacrificial layer is etched to singulate the die and to form a frame from the retainer and the substrate. The frame and handle wafer, which retain the singulated die in place, can be attached together with a clamp or a clip and to form a package for the singulated die. One or more stops can be formed from the device layer(s) to limit a sliding motion of the singulated die.

  12. Vacuum die attach for integrated circuits

    DOEpatents

    Schmitt, E.H.; Tuckerman, D.B.

    1991-09-10

    A thin film eutectic bond for attaching an integrated circuit die to a circuit substrate is formed by coating at least one bonding surface on the die and substrate with an alloying metal, assembling the die and substrate under compression loading, and heating the assembly to an alloying temperature in a vacuum. A very thin bond, 10 microns or less, which is substantially void free, is produced. These bonds have high reliability, good heat and electrical conduction, and high temperature tolerance. The bonds are formed in a vacuum chamber, using a positioning and loading fixture to compression load the die, and an IR lamp or other heat source. For bonding a silicon die to a silicon substrate, a gold silicon alloy bond is used. Multiple dies can be bonded simultaneously. No scrubbing is required. 1 figure.

  13. Vacuum die attach for integrated circuits

    DOEpatents

    Schmitt, Edward H.; Tuckerman, David B.

    1991-01-01

    A thin film eutectic bond for attaching an integrated circuit die to a circuit substrate is formed by coating at least one bonding surface on the die and substrate with an alloying metal, assembling the die and substrate under compression loading, and heating the assembly to an alloying temperature in a vacuum. A very thin bond, 10 microns or less, which is substantially void free, is produced. These bonds have high reliability, good heat and electrical conduction, and high temperature tolerance. The bonds are formed in a vacuum chamber, using a positioning and loading fixture to compression load the die, and an IR lamp or other heat source. For bonding a silicon die to a silicon substrate, a gold silicon alloy bond is used. Multiple dies can be bonded simultaneously. No scrubbing is required.

  14. Dr. Wernher Von Braun presents a certificate

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Dr. Wernher Von Braun (left), director of the Marshall Space Flight Center, presents a humorous certificate to Major General Charles W. Eifler, commanding general of Redstone Arsenal, at the close of a farewell luncheon for the general prior to General Eifler moving to a new European duty station.

  15. [The Costantin Von Economo's lethargic encefalitis

    PubMed

    Pistacchio, E.

    1998-01-01

    Starting from the Constantin Von Economo's description of a "new" disease, the lethargic encephalitis, the author delineates the history of an infectious sleeping sickness that caused epidemics in Europe from 1917 to 1928 and led to create, in Italy, the "Institutes for Encephalitis".

  16. Dr. von Braun Visits Huntsville Boys Club

    NASA Technical Reports Server (NTRS)

    1961-01-01

    Dr. von Braun, Director of Marshall Space Flight Center (MSFC) and chairman of this year's United Givers Fund (UGF) drive at MSFC, takes time out from the problems of sending a man to the Moon to talk baseball with 11-year-old Randy Smith at the Huntsville Boys Club.

  17. Dr. von Braun Discusses 'Bottle Suit' Concept

    NASA Technical Reports Server (NTRS)

    1954-01-01

    Dr. Wernher von Braun (center), then Chief of the Guided Missile Development Division at Redstone Arsenal, Alabama, discusses a 'bottle suit' model with Dr. Heinz Haber (left), an expert on aviation medicine, and Willey Ley, a science writer on rocketry and space exploration. The three men were at the Disney studios appearing in the motion picture, entitled 'Man in Space.'

  18. A note on derivations of Murray–von Neumann algebras

    PubMed Central

    Kadison, Richard V.; Liu, Zhe

    2014-01-01

    A Murray–von Neumann algebra is the algebra of operators affiliated with a finite von Neumann algebra. In this article, we first present a brief introduction to the theory of derivations of operator algebras from both the physical and mathematical points of view. We then describe our recent work on derivations of Murray–von Neumann algebras. We show that the “extended derivations” of a Murray–von Neumann algebra, those that map the associated finite von Neumann algebra into itself, are inner. In particular, we prove that the only derivation that maps a Murray–von Neumann algebra associated with a factor of type II1 into that factor is 0. Those results are extensions of Singer’s seminal result answering a question of Kaplansky, as applied to von Neumann algebras: The algebra may be noncommutative and may even contain unbounded elements. PMID:24469831

  19. Teeth and implants.

    PubMed

    Palmer, R

    1999-08-28

    An osseointegrated implant restoration may closely resemble a natural tooth. However, the absence of a periodontal ligament and connective tissue attachment via cementum, results in fundamental differences in the adaptation of the implant to occlusal forces, and the structure of the gingival cuff.

  20. A no bleed implant.

    PubMed

    Ersek, R A; Navarro, J A; Nemeth, D Z; Sas, G

    1993-01-01

    Breast implants have evolved from the original saline-filled, smooth-surfaced silicone rubber bag to silicone gel-filled smooth-walled sacs to a combination of a silicone gel-filled bag within a saline-filled sac, and, most recently, a reversed, double-lumen implant with a saline bag inside of a gel-filled bag. Texture-surfaced implants were first used in 1970 when the standard silicone gel-filled implant was covered with a polyurethane foam. Because of concerns about the degradation products of this foam, they were removed from the market in 1991. In 1975 double-lumen silicone textured implants were developed, followed by silicone gel-filled textured implants. In 1990 a new radiolucent, biocompatible gel was produced that reduced the problem of radioopacity of silicone implants. Because of the gel's sufficiently low coefficient of friction, leakage caused by fold flaw fracture may also be decreased. We present a case where this new biocompatible gel implant was repositioned after four months. The resulting scar capsule in this soft breast was thin [< 0.002 cm (0.008 in.)] and evenly textured as a mirror image of the textured silicone surface. Scanning electron microscopy and x-ray defraction spectrophotometry revealed no silicone bleed.

  1. Smoking and dental implants

    PubMed Central

    Kasat, V.; Ladda, R.

    2012-01-01

    Smoking is a prevalent behaviour in the population. The aim of this review is to bring to light the effects of smoking on dental implants. These facts will assist dental professionals when implants are planned in tobacco users. A search of “PubMed” was made with the key words “dental implant,” “nicotine,” “smoking,” “tobacco,” and “osseointegration.” Also, publications on tobacco control by the Government of India were considered. For review, only those articles published from 1988 onward in English language were selected. Smoking has its influence on general as well as oral health of an individual. Tobacco negatively affects the outcome of almost all therapeutic procedures performed in the oral cavity. The failure rate of implant osseointegration is considerably higher among smokers, and maintenance of oral hygiene around the implants and the risk of peri-implantitis are adversely affected by smoking. To increase implant survival in smokers, various protocols have been recommended. Although osseointegrated dental implants have become the state of the art for tooth replacement, they are not without limitations or complications. In this litigious era, it is extremely important that the practitioner clearly understands and is able and willing to convey the spectrum of possible complications and their frequency to the patients. PMID:24478965

  2. Batteryless implanted echosonometer

    NASA Technical Reports Server (NTRS)

    Kojima, G. K.

    1977-01-01

    Miniature ultrasonic echosonometer implanted within laboratory animals obtains energy from RF power oscillator that is electronically transduced via induction loop to power receiving loop located just under animal's skin. Method of powering device offers significant advantages over those in which battery is part of implanted package.

  3. Implantable CMOS Biomedical Devices

    PubMed Central

    Ohta, Jun; Tokuda, Takashi; Sasagawa, Kiyotaka; Noda, Toshihiko

    2009-01-01

    The results of recent research on our implantable CMOS biomedical devices are reviewed. Topics include retinal prosthesis devices and deep-brain implantation devices for small animals. Fundamental device structures and characteristics as well as in vivo experiments are presented. PMID:22291554

  4. Implantable, Ingestible Electronic Thermometer

    NASA Technical Reports Server (NTRS)

    Kleinberg, Leonard

    1987-01-01

    Small quartz-crystal-controlled oscillator swallowed or surgically implanted provides continuous monitoring of patient's internal temperature. Receiver placed near patient measures oscillator frequency, and temperature inferred from previously determined variation of frequency with temperature. Frequency of crystal-controlled oscillator varies with temperature. Circuit made very small and implanted or ingested to measure internal body temperature.

  5. Percutaneous and skeletal biocarbon implants

    NASA Technical Reports Server (NTRS)

    Mooney, V.

    1977-01-01

    Review of carbon implants developed by NASA discussed four different types of implants and subsequent improvements. Improvements could be of specific interest to rehabilitation centers and similar organizations.

  6. Graphene for Biomedical Implants

    NASA Astrophysics Data System (ADS)

    Moore, Thomas; Podila, Ramakrishna; Alexis, Frank; Rao, Apparao; Clemson Bioengineering Team; Clemson Physics Team

    2013-03-01

    In this study, we used graphene, a one-atom thick sheet of carbon atoms, to modify the surfaces of existing implant materials to enhance both bio- and hemo-compatibility. This novel effort meets all functional criteria for a biomedical implant coating as it is chemically inert, atomically smooth and highly durable, with the potential for greatly enhancing the effectiveness of such implants. Specifically, graphene coatings on nitinol, a widely used implant and stent material, showed that graphene coated nitinol (Gr-NiTi) supports excellent smooth muscle and endothelial cell growth leading to better cell proliferation. We further determined that the serum albumin adsorption on Gr-NiTi is greater than that of fibrinogen, an important and well understood criterion for promoting a lower thrombosis rate. These hemo-and biocompatible properties and associated charge transfer mechanisms, along with high strength, chemical inertness and durability give graphene an edge over most antithrombogenic coatings for biomedical implants and devices.

  7. Die Anfaenge der Melker Bibliothek - Neue Erkenntnisse zu Handschriften und Fragmenten aus der Zeit vor 1200

    NASA Astrophysics Data System (ADS)

    Glaßner, Christine; Haidinger, Alois

    1996-04-01

    Untersuchung der zeitnahen Eintragungen in diese Handschrift gelang es, die Tätigkeit von zumindest drei wichtigen, im 12. Jahrhundert in Melk identifizierbaren, namentlich nicht bekannten Schreibern chronologisch zuzuordnen. Erstmals wurden die nur fragmentarisch als Makulatur in den Bucheinbänden erhaltenen Handschriften in die Untersuchung einbezogen, so dass für die Wende vom 12. zum 13. Jahrhundert ein Bücherbestand von 68 Handschriften erschlossen werden konnte. Besonders hervorzuheben ist, dass in der Sonderausstellung von 1996 und im Begleitband erstmals eingehend die Bedeutung der ältesten Melker Handschrift, Cod. 412 aus dem frühen 9. Jahrhundert mit naturwissenschaftlichen Texten des Beda Venerabilis, als Vorlage für drei weitere Handschriften diente: Vatikan, Cod. Vat. lat. 643, abgeschrieben wahrscheinlich in Melk, davon abhängig Zwettl, Cod. 296, und Klosterneuburg, Cod. 685. Die Abschriften der Melker Beda-Handschrift sind inhaltlich fast identisch, allerdings um den im Mittelalter fälschlicherweise Beda Venerabilis zugeschriebenen Sternbilderkatalog erweitert.

  8. Restoration of a modified solid abutment of the ITI dental implant system: one of the most unique systems in implant dentistry.

    PubMed

    Charters, R T

    2001-01-01

    Although this system requires the use of some different impression techniques, it provides the dentist and technician a unique and simple method to restore a missing tooth with an implant-retained crown. The Straumann ITI impression coping and analog system allow the fabrication of a hybrid die for predictable results.

  9. Single implant tooth replacement.

    PubMed

    Briley, T F

    1998-01-01

    It has been shown that direct bone anchorage of dental implants will provide long-term predictability for single tooth implants and multi-unit implants. The function of implant-supported restoration is now routinely achieved. The real challenge facing the restorative dentist and laboratory technician is to achieve optimal aesthetics. The learning objective of this article is to review the prosthodontic procedures essential to maximizing natural aesthetics in implant supported restorations. It will provide a review of master impression techniques, prepable titanium abutments and designing the cement on restoration. Particular emphasis is directed to the soft tissue model from which a series of sequenced techniques can be followed to achieve optimal aesthetics. Analysis of the implant alignment with regard to the neighboring teeth will result in having to make a choice of which prepable abutment will maximize the aesthetic result. The following case outlines how to replace a single missing tooth using an externally hexed implant system and a prefabricated titanium abutment on a 26-year-old male patient.

  10. Boron implanted strontium titanate

    NASA Astrophysics Data System (ADS)

    Cooper, C. J. M.

    Single crystals of strontium titanate implanted with boron were found to have highly conductive surface layers. The effects of varying dose from 10 to the 16th power to 10 to the 17th power ions/sq cm, implantation voltage from 50 to 175 keV and annealing conditions on the room temperature surface resistance and Hall mobility are presented. Variation of the implantation voltage did not have a major effect on the sheet resistances obtained by boron implantation of strontium titanate, while dose and annealing conditions have major effects. Doses of 5 x 10 to the 16th power ions/sq cm required annealing on the order of one hour at 500 K for maximum reduction of the room temperature resistance in the implanted layer. Samples implanted with a dose of 1 x 10 to the 17th power ions/sq cm required slightly higher temperatures (approximately 575 K) to obtain a minimum resistance at room temperature. Long term (several weeks) room temperature annealing was found to occur in high dose samples. After one to two months at room temperature followed by an anneal to 575 K, the surface resistances were found to be lower than those produced by the annealing of a freshly implanted sample to 575 K.

  11. Dental Implant Systems

    PubMed Central

    Oshida, Yoshiki; Tuna, Elif B.; Aktören, Oya; Gençay, Koray

    2010-01-01

    Among various dental materials and their successful applications, a dental implant is a good example of the integrated system of science and technology involved in multiple disciplines including surface chemistry and physics, biomechanics, from macro-scale to nano-scale manufacturing technologies and surface engineering. As many other dental materials and devices, there are crucial requirements taken upon on dental implants systems, since surface of dental implants is directly in contact with vital hard/soft tissue and is subjected to chemical as well as mechanical bio-environments. Such requirements should, at least, include biological compatibility, mechanical compatibility, and morphological compatibility to surrounding vital tissues. In this review, based on carefully selected about 500 published articles, these requirements plus MRI compatibility are firstly reviewed, followed by surface texturing methods in details. Normally dental implants are placed to lost tooth/teeth location(s) in adult patients whose skeleton and bony growth have already completed. However, there are some controversial issues for placing dental implants in growing patients. This point has been, in most of dental articles, overlooked. This review, therefore, throws a deliberate sight on this point. Concluding this review, we are proposing a novel implant system that integrates materials science and up-dated surface technology to improve dental implant systems exhibiting bio- and mechano-functionalities. PMID:20480036

  12. The Right To Die. Public Talk Series.

    ERIC Educational Resources Information Center

    Pasquerella, Lynn

    This program guide on the right to die provides policy issue information where ethical concerns have a prominent place. Three positions about the right to die are presented: (1) mercy killing and assisted suicide should be legally permitted in certain cases; (2) legal status should be given to living wills and other advance directives that would…

  13. Energy Consumption of Die Casting Operations

    SciTech Connect

    Jerald Brevick; clark Mount-Campbell; Carroll Mobley

    2004-03-15

    Molten metal processing is inherently energy intensive and roughly 25% of the cost of die-cast products can be traced to some form of energy consumption [1]. The obvious major energy requirements are for melting and holding molten alloy in preparation for casting. The proper selection and maintenance of melting and holding equipment are clearly important factors in minimizing energy consumption in die-casting operations [2]. In addition to energy consumption, furnace selection also influences metal loss due to oxidation, metal quality, and maintenance requirements. Other important factors influencing energy consumption in a die-casting facility include geographic location, alloy(s) cast, starting form of alloy (solid or liquid), overall process flow, casting yield, scrap rate, cycle times, number of shifts per day, days of operation per month, type and size of die-casting form of alloy (solid or liquid), overall process flow, casting yield, scrap rate, cycle times, number of shifts per day, days of operation per month, type and size of die-casting machine, related equipment (robots, trim presses), and downstream processing (machining, plating, assembly, etc.). Each of these factors also may influence the casting quality and productivity of a die-casting enterprise. In a die-casting enterprise, decisions regarding these issues are made frequently and are based on a large number of factors. Therefore, it is not surprising that energy consumption can vary significantly from one die-casting enterprise to the next, and within a single enterprise as function of time.

  14. Prediction of Part Distortion in Die Casting

    SciTech Connect

    R. Allen Miller

    2005-03-30

    The die casting process is one of the net shape manufacturing techniques and is widely used to produce high production castings with tight tolerances for many industries. An understanding of the stress distribution and the deformation pattern of parts produced by die casting will result in less deviation from the part design specification, a better die design and eventually more productivity and cost savings. This report presents methods that can be used to simulate the die casting process in order to predict the deformation and stresses in the produced part and assesses the degree to which distortion modeling is practical for die casting at the current time. A coupled thermal-mechanical finite elements model was used to simulate the die casting process. The simulation models the effect of thermal and mechanical interaction between the casting and the die. It also includes the temperature dependant material properties of the casting. Based on a designed experiment, a sensitivity analysis was conducted on the model to investigate the effect of key factors. These factors include the casting material model, material properties and thermal interaction between casting and dies. To verify the casting distortion predictions, it was compared against the measured dimensions of produced parts. The comparison included dimensions along and across the parting plane and the flatness of one surface.

  15. Death and Dying: Issues for Educational Gerontologists.

    ERIC Educational Resources Information Center

    Wass, Hannelore, Myers, Jane E.

    1984-01-01

    Reviews research on death orientations, the dying process, and bereavement, with a major focus on the elderly. Suggests that relevant knowledge about death and dying are important for gerontological practitioners and proposes that death-related content be systematically integrated into academic curricula at the preservice and inservice levels.…

  16. Apparatus for restraining and transporting dies

    DOEpatents

    Allison, James W.; LaBarre, Timothy L.

    1994-01-01

    Apparatus for restraining and transporting dies in punch press operations is provided. A floatation platen for supporting a die on the platen's upper surface has a plurality of recessed gas exhaust ports on the platen's lower surface. A source of pressurized gas delivers gas to a platen manifold, for delivery to orifices located in the gas exhaust ports. The flow of gas is controlled by a first valve adjacent the gas source and a second valve adjacent the manifold, with the second valve being used to control the gas flow during movement of the die. In this fashion, a die may be moved on a cushion of air from one workstation to a selected second workstation. A moveable hydraulically operated restraining fixture is also provided, for clamping the die in position during the compacting phase, and for releasing the die after completion of the compacting phase by releasing the hydraulic pressure on the restraining fixture. When pressure in the hydraulic cylinders on the restraining fixture is reversed, the restraining fixture will retract so that there is no contact between the die and the restraining fixture, thereby allowing the die to be removed from a first workstation and moved to a second selected workstation.

  17. Student Nurses' Perception of Death and Dying

    ERIC Educational Resources Information Center

    Niederriter, Joan E.

    2009-01-01

    Student nurses are involved in caring for patients who are actively dying or who have been told they have a terminal illness and are faced with the process of dying. Students encounter these patients in hospitals, nursing homes, at home or in hospice care settings. According to Robinson (2004), "nurses are the healthcare providers that are most…

  18. A double commutant theorem for Murray-von Neumann algebras.

    PubMed

    Liu, Zhe

    2012-05-15

    Murray-von Neumann algebras are algebras of operators affiliated with finite von Neumann algebras. In this article, we study commutativity and affiliation of self-adjoint operators (possibly unbounded). We show that a maximal abelian self-adjoint subalgebra A of the Murray-von Neumann algebra A(f)(R) associated with a finite von Neumann algebra R is the Murray-von Neumann algebra A(f)(A(0)), where A(0) is a maximal abelian self-adjoint subalgebra of R and, in addition, A(0) is A Π R. We also prove that the Murray-von Neumann algebra A(f)(C) with C the center of R is the center of the Murray-von Neumann algebra A(f)(R). Von Neumann's celebrated double commutant theorem characterizes von Neumann algebras R as those for which R'' = R, where R', the commutant of R, is the set of bounded operators on the Hilbert space that commute with all operators in R. At the end of this article, we present a double commutant theorem for Murray-von Neumann algebras.

  19. Nanotechnology for dental implants.

    PubMed

    Tomsia, Antoni P; Lee, Janice S; Wegst, Ulrike G K; Saiz, Eduardo

    2013-01-01

    With the advent of nanotechnology, an opportunity exists for the engineering of new dental implant materials. Metallic dental implants have been successfully used for decades, but they have shortcomings related to osseointegration and mechanical properties that do not match those of bone. Absent the development of an entirely new class of materials, faster osseointegration of currently available dental implants can be accomplished by various surface modifications. To date, there is no consensus regarding the preferred method(s) of implant surface modification, and further development will be required before the ideal implant surface can be created, let alone become available for clinical use. Current approaches can generally be categorized into three areas: ceramic coatings, surface functionalization, and patterning on the micro- to nanoscale. The distinctions among these are imprecise, as some or all of these approaches can be combined to improve in vivo implant performance. These surface improvements have resulted in durable implants with a high percentage of success and long-term function. Nanotechnology has provided another set of opportunities for the manipulation of implant surfaces in its capacity to mimic the surface topography formed by extracellular matrix components of natural tissue. The possibilities introduced by nanotechnology now permit the tailoring of implant chemistry and structure with an unprecedented degree of control. For the first time, tools are available that can be used to manipulate the physicochemical environment and monitor key cellular events at the molecular level. These new tools and capabilities will result in faster bone formation, reduced healing time, and rapid recovery to function.

  20. [Superior mesenteric artery aneurysm treated with endovascular stentgraft implantation].

    PubMed

    Juszkat, Robert; Zarzecka, Anna; Winckiewicz, Marek; Majewski, Wacław

    2012-01-01

    Aneurysms of the superior mesenteric are very rare and comprises 5.5% of all visceral artery aneurysms. A 60-year-old male was admitted to the General and Vascular Surgery Department due to the superior mesenteric artery (SMA) aneurysm, diagnosed in angio CT. Due to wide neck of the aneurysm and its localization in the mid-die segment of the SMA, a decision to implant a stentgraft was made. After surgical exposure of the right common femoral artery, a stentgraft Viabahn was implanted into the SMA. Control angiography revealed total aneurysm exclusion and patent SMA. Periprocedural course was uneventful. Follow-up CT scan 2 year after the procedure revealed no contrast filling of the aneurysm and patent SMA. A stentgraft implantation is a effective method of treatment of the wide-necked SMA aneurysms.

  1. Biomedical implantable microelectronics.

    PubMed

    Meindl, J D

    1980-10-17

    Innovative applications of microelectronics in new biomedical implantable instruments offer a singular opportunity for advances in medical research and practice because of two salient factors: (i) beyond all other types of biomedical instruments, implants exploit fully the inherent technical advantages--complex functional capability, high reliability, lower power drain, small size and weight-of microelectronics, and (ii) implants bring microelectronics into intimate association with biological systems. The combination of these two factors enables otherwise impossible new experiments to be conducted and new paostheses developed that will improve the quality of human life.

  2. Die Deutschen in Wisconsin (Germans in Wisconsin).

    ERIC Educational Resources Information Center

    Wisconsin State Dept. of Public Instruction, Madison.

    The following curriculum units comprise this course book: (1) Germans in a New Home, (2) Contributions of the Germans in Wisconsin, (3) A Letter to Germany, (4) Germans Come to Kingston, (5) First a Soldier, Then a Man of the Church (about Heinrich von Rohr), (6) A Visiting German, and (7) Germans and Music. Each unit begins with a reading of…

  3. Influence of die geometry and material selection on the behavior of protective die covers in closed-die forging

    NASA Astrophysics Data System (ADS)

    Yu, Yingyan; Rosenstock, Dirk; Wolfgarten, Martin; Hirt, Gerhard

    2016-10-01

    Due to the fact that tooling costs make up to 30% of total costs of the final forged part, the tool life is always one main research topic in closed-die forging [1]. To improve the wear resistance of forging dies, many methods like nitriding and deposition of ceramic layers have been used. However, all these methods will lose its effect after a certain time, then tool repair or exchange is needed, which requires additional time and costs. A new method, which applies an inexpensive and changeable sheet metal on the forging die to protect it from abrasive wear, was firstly proposed in [2]. According to the first investigation, the die cover is effective for decreasing thermal and mechanical loads, but there are still several challenges to overcome in this concept, like wrinkling and thinning of the die cover. Therefore, an experimental study using different geometries and die cover materials is presented within this work. The results indicate the existence of feasible application cases of this concept, since conditions are found under which a die cover made of 22MnB5 still keeps its original shape even after 7 forging cycles.

  4. From the classical to the generalized von Karman and Marguerre-von Karman equations

    NASA Astrophysics Data System (ADS)

    Ciarlet, Philippe G.; Gratie, Liliana

    2006-06-01

    In this work, we describe and analyze two models that were recently proposed for modeling generalized von Karman plates and generalized Marguerre-von Karman shallow shells.First, we briefly review the "classical" von Karman and Marguerre-von Karman equations, their physical meaning, and their mathematical justification. We then consider the more general situation where only a portion of the lateral face of a nonlinearly elastic plate or shallow shell is subjected to boundary conditions of von Karman type, while the remaining portion is free. Using techniques from formal asymptotic analysis, we obtain in each case a two-dimensional boundary value problem that is analogous to, but is more general than, the classical equations.In particular, it is remarkable that the boundary conditions for the Airy function can still be determined on the entire boundary of the nonlinearly elastic plate or shallow shell solely from the data.Following recent joint works, we then reduce these more general equations to a single "cubic" operator equation, which generalizes an equation introduced by Berger and Fife, and whose sole unknown is the vertical displacement of the shell. We next adapt an elegant compactness method due to Lions for establishing the existence of a solution to this operator equation.

  5. [Molecular biology of von Willebrand disease].

    PubMed

    Melo-Nava, Brenda; Peñaloza, Rosenda

    2007-01-01

    Von Willebrand Factor (VWF) is a large multimeric glycoprotein expressed in the megakaryocytes and endothelial cells of all vertebrates. It participates fundamentally in the primary and secondary hemostasis because it induces the adhesion of platelets to vascular subendothelium and promotes aggregation of platelets when blood vessels and capillaries are damaged. In addition, VWF links to factor VIII which avoids its proteolysis. The deficiency or the inadequate synthesis of the VWF causes von Willebrand disease (VWD), which is the most common hereditary bleeding disorder in humans principally from mucous and cutaneous sites. VWD is difficult to detect with accuracy due to interrelation among VWF with different components of hemostasis, although it is performed by different tests of haemostatic system, and the basic mechanisms in VWD are herein emphasized. The diagnosis of VWD is difficult due to the heterogeneous manifestation of the disease, which also complicates its classification. This article focuses on the molecular aspects of the disease and discusses their possible clinical implications.

  6. Vascular Manifestations of von Recklinghausen's Disease

    PubMed Central

    Fye, Kenneth H.; Jacobs, Richard P.; Roe, Robert L.

    1975-01-01

    A casual relationship between von Recklinghausen's disease, or neurofibromatosis, and arteriolar abnormalities has been reported in the European literature. A patient was seen who had biopsy-proved neurofibromatosis and renovascular hypertension and retroperitoneal bleeding. An arteriographic study showed multiple small aneurysms throughout the coeliac axis, the superior mesenteric artery and in several small intrarenal vessels. Renal vein renin levels were elevated particularly in the right renal vein, supporting the diagnosis of renovascular hypertension. Both the aneurysms seen in angiographic studies and the retroperitoneal hemorrhage are probably vascular manifestations of von Recklinghausen's disease. Support for this conclusion is enhanced by the absence of clinical, laboratory or histologic data supporting the only tenable differential diagnosis, periarteritis nodosa. ImagesFigure 1.Figure 2.Figure 3.Figure 4. PMID:803743

  7. Management of the von Roos operator

    NASA Astrophysics Data System (ADS)

    Molinar-Tabares, Martin; Castro-Arce, Lamberto; Figueroa-Navarro, Carlos; Campos-Garcia, Julio

    When an electron is inside a semiconductor medium its effective mass rises from the shielding of the crystalline structure. When we have a semiconductor with a constant concentration the effective mass has a fixed value, and in this case, it can be easy to solve the Schrodinger equation of the particle, but if the concentration varies spatially, the effective mass will no longer constant and the solution can be difficult to find. The general form of the kinetic energy operator for a particle with variable mass is proposed for von Roos, this operator is characterized by some parameters whose values are subjected to a restriction. From a numerical solution of the Schrodinger equation we analyze the energies of an electron with position-dependent effective mass working with some values of the parameter of the von Roos operator. We acknowledge the support of SNI CONACYT.

  8. Implantable cardioverter-defibrillator

    MedlinePlus

    ... ncbi.nlm.nih.gov/pubmed/23265327 . Swerdlow CD, Wang PJ, Zipes DP. Pacemakers and implantable cardioverter-defibrillators. ... and lifestyle Controlling your high blood pressure Dietary fats explained Fast food tips Heart attack - discharge Heart ...

  9. Biocompatibility of surgical implants

    NASA Technical Reports Server (NTRS)

    Kaelble, D. H.

    1979-01-01

    Method of selecting biocompatible materials for surgical implants uses fracture mechanic relationships and surface energies of candidate materials in presence of blood plasma. Technique has been used to characterize 190 materials by parameters that reflect their biocompatibility.

  10. Risks of Breast Implants

    MedlinePlus

    ... has traveled to other parts of the body. Connective Tissue Disease The FDA has not detected any association between silicone gel-filled breast implants and connective tissue disease, breast cancer, or reproductive problems. In order ...

  11. Breast Reconstruction with Implants

    MedlinePlus

    ... removes your breast to treat or prevent breast cancer. One type of breast reconstruction uses breast implants — silicone devices filled with silicone gel or salt water (saline) — to reshape your breasts. Breast reconstruction ...

  12. Urinary incontinence - injectable implant

    MedlinePlus

    Intrinsic sphincter deficiency repair; ISD repair; Injectable bulking agents for stress urinary incontinence ... Urine leakage that gets worse Pain where the injection was done Allergic reaction to the material Implant ...

  13. Breast reconstruction - implants

    MedlinePlus

    ... cosmetic surgery after breast cancer can improve your sense of well-being and your quality of life. Alternative Names Breast implants surgery References Roehl KR, Wilhelmi BJ, Phillips LG. Breast reconstruction. ...

  14. Superelastic Orthopedic Implant Coatings

    NASA Astrophysics Data System (ADS)

    Fournier, Eric; Devaney, Robert; Palmer, Matthew; Kramer, Joshua; El Khaja, Ragheb; Fonte, Matthew

    2014-07-01

    The demand for hip and knee replacement surgery is substantial and growing. Unfortunately, most joint replacement surgeries will fail within 10-25 years, thereby requiring an arduous, painful, and expensive revision surgery. To address this issue, a novel orthopedic implant coating material ("eXalt") has been developed. eXalt is comprised of super elastic nitinol wire that is knit into a three-dimensional spacer fabric structure. eXalt expands in vivo to conform to the implantation site and is porous to allow for bone ingrowth. The safety and efficacy of eXalt were evaluated through structural analysis, mechanical testing, and a rabbit implantation model. The results demonstrate that eXalt meets or exceeds the performance of current coating technologies with reduced micromotion, improved osseointegration, and stronger implant fixation in vivo.

  15. Simple Implant Augmentation Rhinoplasty

    PubMed Central

    Nguyen, Anh H.; Bartlett, Erica L.; Kania, Katarzyna; Bae, Sang Mo

    2015-01-01

    Augmentation rhinoplasty among Asian patients is often performed to improve the height of the nasal dorsum. As the use of autogenous tissues poses certain limitations, alloplastic materials are a viable alternative with a long history of use in Asia. The superiority of one implant prosthesis over another for augmentation rhinoplasty is a matter of debate, with each material representing varying strengths and weaknesses, indications for use, and precautions to consider in nasal implant placement. An implant prosthesis should be used on a case-by-case basis. Augmentation rhinoplasty requires the consideration of specific anatomical preoperative factors, including the external nose, nasal length, nasofrontal angle, humps, and facial proportions. It is equally important to consider several operative guidelines to appropriately shape implants to minimize the occurrence of adverse effects and postoperative complications. The most common postoperative complications include infection, nasal height change, movement of implant prosthesis, and silicone implant protrusion. In addition, the surgeon should consider the current standards of Asian beauty aesthetics to better understand the patient's desired outcome. PMID:26648804

  16. Biomaterials in cochlear implants

    PubMed Central

    Stöver, Timo; Lenarz, Thomas

    2011-01-01

    The cochlear implant (CI) represents, for almost 25 years now, the gold standard in the treatment of children born deaf and for postlingually deafened adults. These devices thus constitute the greatest success story in the field of ‘neurobionic’ prostheses. Their (now routine) fitting in adults, and especially in young children and even babies, places exacting demands on these implants, particularly with regard to the biocompatibility of a CI’s surface components. Furthermore, certain parts of the implant face considerable mechanical challenges, such as the need for the electrode array to be flexible and resistant to breakage, and for the implant casing to be able to withstand external forces. As these implants are in the immediate vicinity of the middle-ear mucosa and of the junction to the perilymph of the cochlea, the risk exists – at least in principle – that bacteria may spread along the electrode array into the cochlea. The wide-ranging requirements made of the CI in terms of biocompatibility and the electrode mechanism mean that there is still further scope – despite the fact that CIs are already technically highly sophisticated – for ongoing improvements to the properties of these implants and their constituent materials, thus enhancing the effectiveness of these devices. This paper will therefore discuss fundamental material aspects of CIs as well as the potential for their future development. PMID:22073103

  17. Contraceptive implants and lactation.

    PubMed

    Díaz, Soledad

    2002-01-01

    The safety and efficacy of four contraceptive implants, plant, Implanon, Nestorone and Elcometrine, have been evaluated during use in the postpartum period by lactating women. These implants provide highly effective contraceptive protection with no negative effect on breastfeeding or infant growth and development. Breastfeeding women initiating Norplant use in the second postpartum month experience significantly longer periods of amenorrhea than do untreated women or intrauterine device users. After weaning, the bleeding pattern is similar to that observed in non-nursing women. Norplant use does not affect bone turnover and density during lactation. Norplant and Implanon release orally active progestins while Nestorone and Elcometrine implants release an orally inactive progestin, which represents an advantage since the infant should be free of steroidal effects. The infant's daily intake of steroids (estimated from concentrations in maternal milk during the first month of use) range from 90 to 100 ng of levonorgestrel (Norplant), 75-120 ng of etonogestrel (Implanon), and 50 ng and 110 ng of Nestorone (Nestorone and Elcometrine implants, respectively). Nursing women needing contraception may use progestin-only implants when nonhormonal methods are not available or acceptable. Implants that deliver orally active steroids should only be used after 6 weeks postpartum to avoid transferring of steroids to the newborn.

  18. Biocompatible implant surface treatments.

    PubMed

    Pattanaik, Bikash; Pawar, Sudhir; Pattanaik, Seema

    2012-01-01

    Surface plays a crucial role in biological interactions. Surface treatments have been applied to metallic biomaterials in order to improve their wear properties, corrosion resistance, and biocompatibility. A systematic review was performed on studies investigating the effects of implant surface treatments on biocompatibility. We searched the literature using PubMed, electronic databases from 1990 to 2009. Key words such as implant surface topography, surface roughness, surface treatment, surface characteristics, and surface coatings were used. The search was restricted to English language articles published from 1990 to December 2009. Additionally, a manual search in the major dental implant journals was performed. When considering studies, clinical studies were preferred followed by histological human studies, animal studies, and in vitro studies. A total of 115 articles were selected after elimination: clinical studies, 24; human histomorphometric studies, 11; animal histomorphometric studies, 46; in vitro studies, 34. The following observations were made in this review: · The focus has shifted from surface roughness to surface chemistry and a combination of chemical manipulations on the porous structure. More investigations are done regarding surface coatings. · Bone response to almost all the surface treatments was favorable. · Future trend is focused on the development of osteogenic implant surfaces. Limitation of this study is that we tried to give a broader overview related to implant surface treatments. It does not give any conclusion regarding the best biocompatible implant surface treatment investigated till date. Unfortunately, the eventually selected studies were too heterogeneous for inference of data.

  19. [Larynx: implants and stents].

    PubMed

    Sittel, C

    2009-05-01

    There is a wide variety of devices and materials to be implanted into the human larynx. Some are intended to remain only for a period of time, like laryngeal stents. If removal is not intended the device meets the definition for a medical implant. The majority of implants is used for the treatment of unilateral vocal fold immobility. There a 2 types of implants serving this purpose: Implants in a stricter sense are devices of solid material, which are brought into the paraglottic space through a window in the laryngeal framework (medialization thyroplasty). Several different products are presented in this review. In contrast, there are different substances available for endoscopic injection into the paralyzed vocal fold (injection laryngoplasty). Since some of these substances show a corpuscular consistency and a high viscosity they need to be deposited into the lateral paraglottic space. Therefore, the term "injectable implants" has been coined for these materials. The different substances available are discussed in detail in this review. Laryngeal stents are primarily used in the early postoperative phase after open reconstruction of the larynx. The different devices available on the market are described with their specific characteristics and intended use.

  20. Portrait of Dr. Von Braun with Walt Disney, 1954.

    NASA Technical Reports Server (NTRS)

    1954-01-01

    Marshall Center Director Dr. Wernher Von Braun is pictured with Walt Disney during a visit to the Marshall Space Flight Center in 1954. In the 1950s, Dr. Von Braun while working in California on the Saturn project, also worked with Disney studios as a technical director in making three films about Space Exploration for television. Disney's tour of Marshall in 1965 was Von Braun's hope for a renewed public interest in the future of the Space Program at NASA.

  1. Neue biosensorische Prinzipien für die Hämoglobin-A1c Bestimmung

    NASA Astrophysics Data System (ADS)

    Stöllner, Daniela

    2002-06-01

    Hämoglobin-A1c (HbA1c) ist ein Hämoglobin (Hb)-Subtypus, der durch nicht-enzymatische Glykierung des N-terminalen Valinrestes der Hämoglobin-beta-Kette entsteht. Das gemessene Verhältnis von HbA1c zum Gesamt-Hämoglobin (5-20 % bei Diabetikern) repräsentiert den Mittelwert der Blutglucosekonzentration über einen zweimonatigen Zeitraum und stellt zur Beurteilung der diabetischen Stoffwechsellage eine Ergänzung zur Akutkontrolle der Glukosekonzentration dar. Ziel der vorliegenden Arbeit war es, einen amperometrischen Biosensor für die Bestimmung des medizinisch relevanten Parameters HbA1c zu entwickeln. Durch Selektion geeigneter Bioerkennungselemente und deren Immobilisierung unter Erhalt der Bindungsfunktion für die Zielmoleküle Hämoglobin bzw. HbA1c wurden spezifische, hochaffine und regenerationsstabile Sensoroberflächen geschaffen. Für die Entwicklung des HbA1c-Biosensors wurden zwei Konzepte - Enzymsensor und Immunosensor - miteinander verglichen. Die enzymatische Umsetzung von HbA1c erfolgte mit der Fructosylamin Oxidase (FAO) aus Pichia pastoris N 1-1 unter Freisetzung von H2O2, welches sowohl optisch über eine Indikatorreaktion als auch elektrochemisch nach Einschluss der FAO in PVA-SbQ und Fixierung des Immobilisats vor einer H2O2-Elektrode nachgewiesen wurde. Die Kalibration des Enzymsensors mit der HbA1c-Modellsubstanz Fructosyl-Valin ergab Nachweisgrenzen, die ausserhalb des physiologisch relevanten HbA1c-Konzentrationsbereich lagen. Aus der Umsetzung von glykierten Peptiden mit einer nicht HbA1c analogen Aminosäurensequenz, z.B. Fructosyl-Valin-Glycin wurde zudem eine geringe HbA1c-Spezifität abgeleitet. Für den Immunosensor wurden zwei heterogene Immunoassay-Formate unter Verwendung von hochaffinen und spezifischen Antikörpern in Kombination mit Glucose Oxidase (GOD) als Markerenzym zum Nachweis von HbA1c untersucht. Beim indirekt-kompetitiven Immunoassay wurde anstelle des kompletten HbA1c-Moleküls das glykierte Pentapeptid

  2. Dr. von Braun and Army Ballistics Missile Agency (ABMA) Group

    NASA Technical Reports Server (NTRS)

    1959-01-01

    This photograph of Dr. von Braun, shown here to the left of General Bruce Medaris, was taken in the fall of 1959, immediately prior to Medaris' retirement from the Army. At the time, von Braun and his associates worked for the Army Ballistics Missile Agency in Huntsville, Alabama. Those in the photograph have been identified as Ernst Stuhlinger, Frederick von Saurma, Fritz Mueller, Hermarn Weidner, E.W. Neubert (partially hidden), W.A. Mrazek, Karl Heimburg, Arthur Rudolph, Otto Hoberg, von Braun, Oswald Lange, Medaris, Helmut Hoelzer, Hans Maus, E.D. Geissler, Hans Heuter, and George Constan.

  3. PT2385 for the Treatment of Von Hippel-Lindau Disease-Associated Clear Cell Renal Cell Carcinoma

    ClinicalTrials.gov

    2017-04-04

    VHL Gene Mutation; VHL; VHL Syndrome; VHL Gene Inactivation; Von Hippel; Von Hippel-Lindau Disease; Von Hippel's Disease; Von Hippel-Lindau Syndrome, Modifiers of; Clear Cell Renal Cell Carcinoma; Clear Cell RCC; ccRCC

  4. FEM Analysis of Mandibular Prosthetic Overdenture Supported by Dental Implants: Evaluation of Different Retention Methods

    PubMed Central

    Cicciù, M.; Cervino, G.; Bramanti, E.; Lauritano, F.; Lo Gudice, G.; Scappaticci, L.; Rapparini, A.; Guglielmino, E.; Risitano, G.

    2015-01-01

    Prosthetic rehabilitation of total edentulous jaws patients is today a common technique that clinicians approach in their daily practice. The use of dental implants for replacing missing teeth is going to be a safe technique and the implant-prosthetic materials give the possibility of having long-term clinical success. Aim of this work is to evaluate the mechanical features of three different prosthetic retention systems. By applying engineering systems of investigations like FEM and von Mises analyses, how the dental implant material holds out against the masticatory strength during the chewing cycles has been investigated. Three common dental implant overdenture retention systems have been investigated. The ball attachment system, the locator system, and the common dental abutment have been processed by Ansys Workbench 15.0 and underwent FEM and von Mises investigations. The elastic features of the materials used in the study have been taken from recent literature data. Results revealed different response for both types of device, although locator system showed better results for all conditions of loading. The data of this virtual model show all the features of different prosthetic retention systems under the masticatory load. Clinicians should find the better prosthetic solution related to the patients clinical condition in order to obtain long-term results. PMID:26798405

  5. Is there a moral duty to die?

    PubMed

    Corlett, J A

    2001-01-01

    In recent years, there has been a great deal of philosophical discussion about the alleged moral right to die. If there is such a moral right, then it would seem to imply a moral duty of others to not interfere with the exercise of the right. And this might have important implications for public policy insofar as public policy ought to track what is morally right. But is there a moral duty to die? If so, under what conditions, if any, ought one to have such a duty, and why? In this paper, I distinguish between different moral grounds for the putative moral duty to die: deontological, intuitionist, and contractarian. Subsequently, I argue in support of Paul Menzel's theory of health care distribution. More precisely, I concur with his claim that there is a moral duty to die inexpensively in health care contexts. Then I provide and defend a philosophical analysis of the conditions in which such a duty could exist.

  6. House of Lords debates assisted dying (again).

    PubMed

    2003-07-01

    Lord Joffe's Patient (Assisted Dying) Bill (see Bulletin 187) had its Second Reading on 6 June. The debate was lively, informed and inevitably somewhat polarised. However, some common themes emerged and are outlined below.

  7. Casting Characteristics of Aluminum Die Casting Alloys

    SciTech Connect

    Makhlouf M. Makhlouf; Diran Apelian

    2002-02-05

    The research program investigates the casting characteristics of selected aluminum die casting alloys. Specifically, the alloys' tendencies towards die soldering and sludge formation, and the alloys' fluidity and machinability are evaluated. It was found that: When the Fe and Mn contents of the alloy are low; caution has to be taken against possible die soldering. When the alloy has a high sludge factor, particularly a high level of Fe, measures must be taken to prevent the formation of large hardspots. For this kind of alloy, the Fe content should be kept at its lowest allowable level and the Mn content should be at its highest possible level. If there are problems in die filling, measures other than changing the alloy chemistry need to be considered first. In terms of alloy chemistry, the elements that form high temperature compounds must be kept at their lowest allowable levels. The alloys should not have machining problems when appropriate machining techniques and machining parameters are used.

  8. Ansätze zur Ordnungsreduktion von nichtlinearen Oszillatormodellen zur Anwendung im Schaltungsentwurf

    NASA Astrophysics Data System (ADS)

    Reit, M.; Bremer, J.-K.; Mathis, W.; Stoop, R.

    2010-10-01

    Im Rahmen dieser Arbeit wird ein Konzept zur Ordnungsreduktion von höherdimensionalen nichtlinearen Oszillatormodellen vorgestellt. Hierbei werden zwei wesentliche Ziele verfolgt. Zum einen wird eine höherdimensionale Modellierung der Oszillatorschaltung verwendet. Hierdurch lassen sich die Einflüsse parasitärer Effekte sowie struktureller Erweiterungen auf das dynamische Verhalten des Systems berücksichtigen. Zum anderen wird durch eine anschließende Ordnungsreduktion über die Methode der Zentrumsmannigfaltigkeit eine zweidimensionale Systembeschreibung erzeugt, deren wesentliche Dynamik derjenigen des höherdimensionalen Systems entspricht. Durch diese, in der Ordnung reduzierte, nichtlineare und parameterabhängige Systembeschreibung wird die Anwendbarkeit nichtlinearer Analysemethoden ermöglicht bzw. vereinfacht. Mit der Anwendung der Andronov-Hopf-Bifurkationsanalyse auf das reduzierte System lässt sich eine Stabilitätsuntersuchung durchführen sowie die Amplitude und Frequenz aller Zustandsgrößen approximieren. Das vorgestellte Konzept wird anhand des Beispielsystems eines LC-Tank-VCOs durchgeführt. In this paper, an order reduction technique for higher-dimensional nonlinear oscillator models, based on a center manifold approach, is presented. By modeling the oscillator circuit in the higher-dimensional state space, influences of parasitic elements and of structural extensions of the oscillator architecture on the dynamical system behavior can be examined. Using the proposed order reduction technique, a generalized second order model will be derived, which includes selected design parameters of the higher order model. By using an Andronov-Hopf bifurcation analysis, the reduced system can be studied with respect to stability as well as the amplitude and frequency of the individual state variables. The concept is applied to the design of LC-tank VCOs.

  9. Thick film silicon growth techniques. [die materials

    NASA Technical Reports Server (NTRS)

    Bates, H. E.; Mlavsky, A. I.; Jewett, D. N.; White, V. E.

    1973-01-01

    The research which was directed toward finding an improved die material is reported. Wetting experiments were conducted with various materials to determine their compatibility with silicon. Work has also continued toward the development of quartz as a die material as new techniques have provided more optimistic results than observed in the past. As a result of the thermal modification previously described, improvements in growth stability have contributed to an increase in ribbon quality.

  10. Machining of Silicon-Ribbon-Forming Dies

    NASA Technical Reports Server (NTRS)

    Menna, A. A.

    1985-01-01

    Carbon extension for dies used in forming silicon ribbon crystals machined precisely with help of special tool. Die extension has edges beveled toward narrow flats at top, with slot precisely oriented and centered between flats and bevels. Cutting tool assembled from standard angle cutter and circular saw or saws. Angle cutters cuts bevels while slot saw cuts slot between them. In alternative version, custom-ground edges or additional circular saws also cut flats simultaneously.

  11. The telescopes of Duke Ernst I, the Pious, of Saxony-Gotha. (German Title: Die Fernrohre von Herzog Ernst I., dem Frommen, von Sachsen-Gotha)

    NASA Astrophysics Data System (ADS)

    Keil, Inge

    Already in the 17th century, there was an interest in astronomy at the court of Gotha, where Duke Ernst I hold one of the largest collections of telescopes at his times, with instruments made by the Augsburg optician Johann Wiesel, by Baruch Spinoza and others. By the help of the inventory of the Kunstkammer the holdings may be documentarily demonstrated.

  12. Celestial Fireworks from Dying Stars

    NASA Astrophysics Data System (ADS)

    2011-04-01

    This image of the nebula NGC 3582, which was captured by the Wide Field Imager on the MPG/ESO 2.2-metre telescope at ESO's La Silla Observatory in Chile, shows giant loops of gas bearing a striking resemblance to solar prominences. These loops are thought to have been ejected by dying stars, but new stars are also being born within this stellar nursery. These energetic youngsters emit intense ultraviolet radiation that makes the gas in the nebula glow, producing the fiery display shown here. NGC 3582 is part of a large star-forming region in the Milky Way, called RCW 57. It lies close to the central plane of the Milky Way in the southern constellation of Carina (The Keel of Jason's ship, the Argo). John Herschel first saw this complex region of glowing gas and dark dust clouds in 1834, during his stay in South Africa. Some of the stars forming in regions like NGC 3582 are much heavier than the Sun. These monster stars emit energy at prodigious rates and have very short lives that end in explosions as supernovae. The material ejected from these dramatic events creates bubbles in the surrounding gas and dust. This is the probable cause of the loops visible in this picture. This image was taken through multiple filters. From the Wide Field Imager, data taken through a red filter are shown in green and red, and data taken through a filter that isolates the red glow characteristic of hydrogen are also shown in red. Additional infrared data from the Digitized Sky Survey are shown in blue. The image was processed by ESO using the observational data identified by Joe DePasquale, from the United States [1], who participated in ESO's Hidden Treasures 2010 astrophotography competition [2]. The competition was organised by ESO in October-November 2010, for everyone who enjoys making beautiful images of the night sky using astronomical data obtained using professional telescopes. Notes [1] Joe searched through ESO's archive and identified datasets that he used to compose his

  13. Living until we die: reflections on the dying person's spiritual agenda.

    PubMed

    Anderson, Herbert

    2006-03-01

    The spiritual agenda for the dying presumes a willingness to face the reality of imminent death. It also depends on support from caregivers who will encourage whatever agency is possible for the one who is dying. The spiritual practices that will enhance agency for the dying include remembering, thanking, relinquishing, waiting, and trusting. The absence of abandonment and the dependable presence of caregivers are essential to create communities and relationships in which hope can be found and sustained.

  14. Die Titicaca-See-Region auf dem Altiplano von Peru und Bolivien und die Folgen eingeführter Fische für Wildarten und ihren Lebensraum

    NASA Astrophysics Data System (ADS)

    Villwock, Wolfgang

    1993-01-01

    In the course of a long-term case study (since 1960) the interaction between different exotic fish (salmonids, atherinids) on the endemic ichthyofauna (genus Orestias: Cyprinodontidae) introduced to the interandean basin of Lake Titicaca was observed. The contribution deals not only with the actual consequences which endanger endemic species but also the socio-economic effects on the native Indian population, both causing further ecological problems in the region of concern.

  15. Influence of custom-made implant designs on the biomechanical performance for the case of immediate post-extraction placement in the maxillary esthetic zone: a finite element analysis.

    PubMed

    Chen, Jianyu; Zhang, Zhiguang; Chen, Xianshuai; Zhang, Xiao

    2017-05-01

    Due to the increasing adoption of immediate implantation strategies and the rapid development of the computer aided design/computer aided manufacturing technology, a therapeutic concept based on patient-specific implant dentistry has recently been reintroduced by many researchers. However, little information is available on the designs of custom-made dental implant systems, especially their biomechanical behavior. The influence of the custom-made implant designs on the biomechanical performance for both an immediate and a delayed loading protocol in the maxillary esthetic zone was evaluated by means of the finite element (FE) method. FE models of three dental implants were considered: a state of the art cylindrical implant and two custom-made implants designed by reverse engineering technology, namely a root-analogue implant and a root-analogue threaded implant. The von Mises stress distributions and micro-motions around the bone-implant interfaces were calculated using ANSYS software. In a comparison of the three implant designs for both loading protocols, a favorable biomechanical performance was observed for the use of root-analogue threaded implant which approximated the geometry of natural anterior tooth and maintained the original long-axis. The results indicated that bone-implant interfacial micro-motion was reduced and a favorable stress distribution after osseointegration was achieved.

  16. Thermal Modelling In Pressure Die Casting

    NASA Astrophysics Data System (ADS)

    Rasgado, M. T. Alonso; Davey, K.; Watari, H.

    2004-06-01

    The pressure die casting process is cyclic and the temperature levels in the die are principally dictated by the total energy received from the casting. It is thus extremely important that any solidification model for the casting is able to predict energy extraction rates to a high degree of accuracy. In this paper an efficient three dimensional hybrid thermal model for the pressure die casting process is described. The finite element method (FEM) is used for modelling heat transfer in the casting, coupled to a boundary element (BE) model for the die. The FEM can efficiently account for the non-linearity introduced by the release of latent heat on solidification, whereas the BEM is ideally suited for modelling linear heat conduction in the die, as surface temperatures are of principal importance. The FE formulation for the casting is based on a control volume capacitance method, which is shown to provide high accuracy and stability. This method is similar to the apparent and effective heat capacitance methods, which are popular approaches used where conduction predominates over other heat transfer mechanisms. These methods involve the specification of element or nodal capacitances to accommodate for the release of latent heat. Unfortunately they suffer from a major drawback in that energy is not correctly transported through elements and so providing a source of inaccuracy. The control volume capacitance method allows for the transport of mass arising from volumetric shrinkage and ensures that energy is correctly transported. The BE model caters for surface phenomena such as boiling in the cooling channels, which is important, as this effectively controls the manner in which energy is extracted. The die temperature is decomposed into two components, one a steady-state part and the other a time-dependent perturbation. This approach enables the transient die temperatures to be calculated in an efficient way, since only die surfaces close to the die cavity are

  17. Extraoral prostheses using extraoral implants.

    PubMed

    Pekkan, G; Tuna, S H; Oghan, F

    2011-04-01

    The aim of this study was to evaluate extraoral prostheses and the use of extraoral implants in patients with facial defects. 10 cases were treated utilizing maxillofacial prostheses employing extraoral implants in five cases. 16 extraoral implants were installed. Seven implants were placed in irradiated sites in the orbital regions. Six implants were placed in mastoid regions and three in a zygoma region that was irradiated. Two implants failed before initial integration was achieved in irradiated areas. Using 14 extraoral implants as anchors, five extraoral prostheses were set. The other five cases were treated with extraoral prostheses without using extraoral implants due to cost and patient-related factors. The data included age, sex, primary disease, implant length, implant failure, prosthetic attachment, radiation therapy, and peri-implant skin reactions. The use of extraoral implants for the retention of extraoral prostheses has simplified the placement, removal, and cleaning of the prosthesis by the patient. The stability of the prostheses was improved by anchors. Clinical and technical problems are presented with the techniques used for their resolution. Using extraoral implants resulted in a high rate of success in retaining facial prostheses and gave good stability and aesthetic satisfaction.

  18. Towards biodegradable wireless implants.

    PubMed

    Boutry, Clémentine M; Chandrahalim, Hengky; Streit, Patrick; Schinhammer, Michael; Hänzi, Anja C; Hierold, Christofer

    2012-05-28

    A new generation of partially or even fully biodegradable implants is emerging. The idea of using temporary devices is to avoid a second surgery to remove the implant after its period of use, thereby improving considerably the patient's comfort and safety. This paper provides a state-of-the-art overview and an experimental section that describes the key technological challenges for making biodegradable devices. The general considerations for the design and synthesis of biodegradable components are illustrated with radiofrequency-driven resistor-inductor-capacitor (RLC) resonators made of biodegradable metals (Mg, Mg alloy, Fe, Fe alloys) and biodegradable conductive polymer composites (polycaprolactone-polypyrrole, polylactide-polypyrrole). Two concepts for partially/fully biodegradable wireless implants are discussed, the ultimate goal being to obtain a fully biodegradable sensor for in vivo sensing.

  19. Approximating incompatible von Neumann measurements simultaneously

    SciTech Connect

    Heinosaari, Teiko; Jivulescu, Maria Anastasia; Reitzner, Daniel; Ziman, Mario

    2010-09-15

    We study the problem of performing orthogonal qubit measurements simultaneously. Since these measurements are incompatible, one has to accept additional imprecision. An optimal joint measurement is the one with the least possible imprecision. All earlier considerations of this problem have concerned only joint measurability of observables, while in this work we also take into account conditional state transformations (i.e., instruments). We characterize the optimal joint instrument for two orthogonal von Neumann instruments as being the Lueders instrument of the optimal joint observable.

  20. [Albrecht von Haller. An illustrious ancestor].

    PubMed

    Peiper, H-J

    2008-05-01

    Albrecht von Haller (1708-1777) was one of the most famous and important men of the eighteenth century. His achievements make him comparable with Lessing and Newton. In Blumenbach's opinion he was one of the enlightenment's greatest thinkers in both versatility and depth. He contributed significantly to developments in medicine, physiology, botany, pharmacology, theology, literature, editing, chronicles, biography, geography, and during his later years in Switzerland jurisprudence and agrarian reform. On the occasion of the 300th anniversary of his birth, important scientific landmarks in his life are described, with special attention to his achievements in the fields of anatomy, physiology, surgery, and experimental research.

  1. Acquired von Willebrand syndrome: von Willebrand factor propeptide to von Willebrand factor antigen ratio predicts remission status

    PubMed Central

    Lee, Adrienne; Sinclair, Gary; Valentine, Karen; James, Paula

    2014-01-01

    We investigated a case of acquired von Willebrand syndrome (AVWS) secondary to a nonneutralizing anti-von Willebrand factor (VWF) antibody associated with an autoimmune disorder. At diagnosis, VWF activity (VWF:Act), antigen (VWF:Ag), multimers, and factor VIII coagulant activity were virtually absent. VWF propeptide (VWFpp) was elevated with an infinitely high VWFpp to VWF:Ag ratio (VWFpp:Ag) consistent with rapid VWF clearance. Immunosuppressive treatment resulted in phenotypic remission 1 with normalization of VWF/factor VIII levels and multimer pattern. However, VWFpp:Ag remained elevated (∼2× normal), consistent with ongoing VWF clearance by the remaining anti-VWF antibody still present by enzyme-linked immunosorbent assay. This suggests that increased VWF secretion was compensating for the incomplete remission state. Relapse occurred when VWFpp:Ag was again infinitely high, with associated decreased VWFpp but unchanged anti-VWF titers; switching the balance to favor VWF clearance over secretion. Complete remission with undetectable anti-VWF occurred only when VWFpp:Ag was normal. This case of relapsing-remitting AVWS demonstrates the use of VWFpp:Ag for predicting remission status. PMID:24951428

  2. Group Theoretical Interpretation of von Neumann's Theorem on Composite Systems.

    ERIC Educational Resources Information Center

    Bergia, S.; And Others

    1979-01-01

    Shows that von Neumann's mathematical theorem on composite systems acquires a transparent physical meaning with reference to a suitable physical example; a composite system in a state of definite angular momentum. Gives an outline of the theorem, and the results are restated in Dirac's notation, thus generalizing von Neumann's results which were…

  3. Virtualized Optical Network (VON) for Future Internet and Applications

    NASA Astrophysics Data System (ADS)

    Jinno, Masahiko; Tsukishima, Yukio; Takara, Hidehiko; Kozicki, Bartlomiej; Sone, Yoshiaki; Sakano, Toshikazu

    A virtualized optical network (VON) is proposed as a key to implementing increased agility and flexibility into the future Internet and applications by providing any-to-any connectivity with the appropriate optical bandwidth at the appropriate time. The VON is enabled by introducing optical transparentization and optical fine granular grooming based on optical orthogonal frequency division multiplexing.

  4. Rare liver tumor: symptomatic giant von Meyenburg complex

    PubMed Central

    Singh, Yardesh; Cawich, Shamir O.; Ramjit, Chunilal; Naraynsingh, Vijay

    2016-01-01

    von Meyenburg complexes are hamartomas that arise from intra-hepatic bile ducts. Symptomatic lesions are uncommon and giant lesions are exceedingly rare. When encountered, they should be excised because there are reports of malignant change in large, symptomatic lesions. We report a case of a symptomatic giant von Meyenburg complex. PMID:28068648

  5. Victor or Villain? Wernher von Braun and the Space Race

    ERIC Educational Resources Information Center

    O'Brien, Jason L.; Sears, Christine E.

    2011-01-01

    Set during the Cold War and space race, this historical role-play focuses on Wernher von Braun's involvement in and culpability for the use of slave laborers to produce V-2 rockets for Nazi Germany. Students will grapple with two central questions. Should von Braun have been allowed to emigrate to the United States given his affiliation with the…

  6. Dr. von Braun Tries Out the Neutral Buoyancy Simulator (NBS)

    NASA Technical Reports Server (NTRS)

    1967-01-01

    Marshall Space Flight Center (MSFC) Director, Dr. von Braun, submerges after spending some time under water in the MSFC Neutral Buoyancy Simulator (NBS). Weighted to a neutrally buoyant condition, Dr. von Braun was able to perform tasks underwater which simulated weightless conditions found in space.

  7. Dr. von Braun Tries Out the Neutral Buoyancy Simulator (NBS)

    NASA Technical Reports Server (NTRS)

    1967-01-01

    Astronaut L. Gordon Cooper checks the neck ring of a space suit worn by Marshall Space Flight Center (MSFC) Director, Dr. von Braun before he submerges into the water of the MSFC Neutral Buoyancy Simulator (NBS). Wearing a pressurized suit and weighted to a neutrally buoyant condition, Dr. von Braun was able to perform tasks underwater which simulated weightless conditions found in space.

  8. Dr. von Braun Tries Out the Neutral Buoyancy Simulator (NBS)

    NASA Technical Reports Server (NTRS)

    1967-01-01

    Marshall Space Flight Center (MSFC) Director, Dr. von Braun, is shown leaving the suiting-up van wearing a pressure suit prepared for a tryout in the MSFC Neutral Buoyancy Simulator (NBS). Weighted to a neutrally buoyant condition, Dr. von Braun was able to perform tasks underwater which simulated weightless conditions found in space.

  9. Implantable Heart Aid

    NASA Technical Reports Server (NTRS)

    1980-01-01

    Medrad utilized NASA's Apollo technology to develop a new device called the AID implantable automatic pulse generator which monitors the heart continuously, recognizes the onset of ventricular fibrillation and delivers a corrective electrical shock. AID pulse generator is, in effect, a miniaturized version of the defibrillator used by emergency squads and hospitals to restore rhythmic heartbeat after fibrillation, but has the unique advantage of being permanently available to the patient at risk. Once implanted, it needs no specially trained personnel or additional equipment. AID system consists of a microcomputer, a power source and two electrodes which sense heart activity.

  10. Hydroxylapatite Otologic Implants

    SciTech Connect

    McMillan, A.D.; Lauf, R.J.; Beale, B.; Johnson, R.

    2000-01-01

    A Cooperative Research and Development Agreement (CRADA) between Lockheed Martin Energy Research Corporation (LMER) and Smith and Nephew Richards Inc. of Bartlett, TN, was initiated in March 1997. The original completion date for the Agreement was March 25, 1998. The purpose of this work is to develop and commercialize net shape forming methods for directly creating dense hydroxylapatite (HA) ceramic otologic implants. The project includes three tasks: (1) modification of existing gelcasting formulations to accommodate HA slurries; (2) demonstration of gelcasting to fabricate green HA ceramic components of a size and shape appropriate to otologic implants: and (3) sintering and evaluation of the HA components.

  11. Combined Therapy of Septicemia with Ofloxacin and/or Synthetic Trehalose Dicorynomycolate (S-TDCM) in Irradiated and Wounded Mice (Die Kombinierte Therapie der Septikaemie mit Ofloxacin und/oder Synthetischem Trehalose- Dicorynomycolat (S-TDCM) bei Bestrahlten und Verwundeten Maeusen)

    DTIC Science & Technology

    1989-01-01

    for effective therapy of polymicrobic infections in irradiated/wounded mice. ZUSAMMENFASSUNG Im Gefolge letaler Bestrahlung fallen MAuse normalerweise...durch die Inhalation von Methoxyfluran andsthetisiert wurden. Eine Stunde nach 8.0 G.- Germma- Bestrahlung wurden dorsal Haut- und Muskelgewebe in Ent

  12. Sensation Following Immediate Breast Reconstruction with Implants.

    PubMed

    Lagergren, Jakob; Wickman, Marie; Hansson, Per

    2010-01-01

    Sensation is a neglected aspect of the outcome of breast reconstructions with implants. The aim of this prospective study was to evaluate the cutaneous somatosensory status in breasts following mastectomy and immediate reconstruction with permanent adjustable prostheses and to analyze the patients' subjective experience of the sensation. Twenty-four consecutive patients diagnosed with invasive or in situ breast carcinoma were examined preoperatively and 2 years after mastectomy and reconstruction, for assessment of perception thresholds for touch, cold, warmth, and heat pain above and below the areola. Von Frey filaments and a Peltier element-based thermode were used. The patients completed a questionnaire concerning their experienced sensation in the reconstructed breast. Using quantitative somato-sensory testing, the sensation to all the examined modalities was significantly impaired compared to preoperatively. Most affected was the area above the areola. Patients given postoperative radiotherapy (n = 9) did not differ from those without radiotherapy (n = 15) regarding any of the modalities. All patients reported reduced sensation in the reconstructed breast compared to that preoperatively. Twenty-three patients stated that the reconstructed breast felt different from the other breast; nevertheless 16 reported that the reconstructed breast felt like a real breast. The study revealed sensation impairment following mastectomy and immediate reconstruction with implants. Patients should be informed about this effect preoperatively to allow adequate expectations regarding the sensation outcome. However, two-thirds of the study patients considered that the reconstructed breast felt like a real breast, which must be one of the main purposes of a breast reconstruction.

  13. Stabile Expression von Sulfotransferasen - allein oder in Kombination mit Cytochrom P450 - in Zelllinien für Mutagenitätsuntersuchungen

    NASA Astrophysics Data System (ADS)

    Pabel, Ulrike

    2003-10-01

    Aromatische Amine und Amide (aAA) sind aufgrund ihrer starken Verbreitung in der menschlichen Umwelt und ihres kanzerogenen Potenzials von groer toxikologischer Bedeutung. Die Kanzerogenität der aAA wird durch die Mutagenität hochreaktiver Stoffwechselprodukte vermittelt, die in zwei sequenziellen katalytischen Reaktionen entstehen. Die erste ist meistens eine N-Hydroxylierung, die oft durch Cytochrom P450 1A2 (CYP1A2) katalysiert wird. Daran schliet sich eine O-Konjugation durch Sulfotransferasen (SULT) oder N-Acetyltransferasen (NAT) an. Die Bioaktivierung ist ein kritischer Parameter für die Übertragbarkeit von Ergebnissen aus Tiermodellen auf den Menschen. Rekombinante in vitro Systeme, die fremdstoffmetabolisierende Enzyme verschiedener Spezies exprimieren, ermöglichen die vergleichende Untersuchung der Bioaktivierung im Menschen und in Versuchstieren. Ziel des Projektes war die Aufklärung der Bioaktivierung der aAA durch humane Enzyme. Im Vordergrund stand die Untersuchung der Rolle humaner SULT in diesem Prozess. Es wurden rekombinante in vitro Systeme, konstruiert, die CYP1A2 und SULT des Menschen koexprimieren. SULT-cDNAs wurden in den Säugerzell Expressionsvektor pMPSV kloniert und in Standardindikatorzellen für Mutagenitätsuntersuchungen (V79 Zellen aus dem Chinesischen Hamster) transfiziert. Das Expressionsniveau von CYP1A2 und SULT wurde mittels Immunblotanalyse und radiometrischen Aktivitätsmessungen charakterisiert. In den rekombinanten Zellen wurden vier aAA als Modellsubstanzen (2-Acetylaminofluoren, 2-Aminoanthracen, 3′-Methyl-4-dimethylaminoazobenzol, 2,4-Diaminotoluol) auf ihre Mutagenität am hprt-Locus hin untersucht.Die aAA waren in Zellen, die keine rekombinanten Enzyme oder lediglich CYP1A2 exprimierten, nicht mutagen. In Zellen, die CYP1A2 und SULT der Subfamilie 1A koexprimierten, erzeugten sie bereits in geringen Konzentrationen klare mutagene Effekte (0,3 µM für 2-Acetylaminofluoren und 3′-Methyl-4

  14. Wernher von Braun and Saturn IB on Launch Pad

    NASA Technical Reports Server (NTRS)

    1968-01-01

    Dr. Wernher von Braun stands in front of a Saturn IB launch vehicle at Kennedy Space Flight Center. Dr. von Braun led a team of German rocket scientists, called the Rocket Team, to the United States, first to Fort Bliss/White Sands, later being transferred to the Army Ballistic Missile Agency at Redstone Arsenal in Huntsville, Alabama. They were further transferred to the newly established NASA/Marshall Space Flight Center (MSFC) in Huntsville, Alabama in 1960, and Dr. von Braun became the first Center Director. Under von Braun's direction, MSFC developed the Mercury-Redstone, which put the first American in space; and later the Saturn rockets, Saturn I, Saturn IB, and Saturn V. The Saturn V launch vehicle put the first human on the surface of the Moon, and a modified Saturn V vehicle placed Skylab, the first United States' experimental space station, into Earth orbit. Dr. von Braun was MSFC Director from July 1960 to February 1970.

  15. Current trends in dental implants

    PubMed Central

    Gaviria, Laura; Salcido, John Paul; Guda, Teja

    2014-01-01

    Tooth loss is very a very common problem; therefore, the use of dental implants is also a common practice. Although research on dental implant designs, materials and techniques has increased in the past few years and is expected to expand in the future, there is still a lot of work involved in the use of better biomaterials, implant design, surface modification and functionalization of surfaces to improve the long-term outcomes of the treatment. This paper provides a brief history and evolution of dental implants. It also describes the types of implants that have been developed, and the parameters that are presently used in the design of dental implants. Finally, it describes the trends that are employed to improve dental implant surfaces, and current technologies used for the analysis and design of the implants. PMID:24868501

  16. Evaluation of design parameters of dental implant shape, diameter and length on stress distribution: a finite element analysis.

    PubMed

    Mohammed Ibrahim, M; Thulasingam, C; Nasser, K S G A; Balaji, V; Rajakumar, M; Rupkumar, P

    2011-09-01

    The aim was to evaluate the design parameters of dental implants shape, diameter and length on stress distribution by finite element analysis (FEA).The objectives of the study was to compare the influence of stress distribution in the implants of screw-vent tapered and parallel design by varying the implant diameter with a standard implant length. Six dental implant models have been simulated three-dimensionally. The influence of diameter and length on stress distribution was evaluated by Group I: for screw-vent tapered design (Zimmer Dental Implant Carlsbad, CA, USA) (1) Dental implant model with diameter 3.7 mm and length 13 mm. (2) Dental implant model with diameter 4.1 mm and length 13 mm. (3) Dental implant model with diameter 4.7 mm and length 13 mm. Group II: for parallel design (Zimmer Dental Implant Carlsbad, CA, USA) (4) Dental implant model with diameter 3.7 mm and length 13 mm. (5) Dental implant model with diameter 4.1 mm and length 13 mm. (6) Dental implant model with diameter 4.7 mm and length 13 mm. The 3-D model of the implant was created in the pro-e wildfire 4.0 software by giving various commands. This model was imported to the ANSYS software through IGES (initial graphic exchange specification) file for further analysis. All six models were loaded with a force of 17.1, 114.6 and 23.4 N in a lingual, an axial and disto-mesial direction respectively, simulating average masticatory force in a natural oblique direction, to analyze the stress distribution on these implants. The increase in implant diameter in Group I and Group II from 3.7 to 4.1 mm and from 4.1 to 4.7 mm with constant 13 mm length for screw-vent tapered and parallel design implant resulted in a reduction in maximum value of Von Mises stress in the bone surrounding the implant was statistically significant at 5% level done by student "t" test. The overall maximum value of Von Mises stress was decreased in parallel design implant diameter of 4.7 mm with constant

  17. A preliminary biomechanical study of a novel carbon-fibre hip implant versus standard metallic hip implants.

    PubMed

    Bougherara, Habiba; Zdero, Rad; Dubov, Anton; Shah, Suraj; Khurshid, Shaheen; Schemitsch, Emil H

    2011-01-01

    Total hip arthroplasty is a widespread surgical approach for treating severe osteoarthritis of the human hip. Aseptic loosening of standard metallic hip implants due to stress shielding and bone loss has motivated the development of new materials for hip prostheses. Numerically, a three-dimensional finite element (FE) model that mimicked hip implants was used to compare a new hip stem to two commercially available implants. The hip implants simulated were a novel CF/PA12 carbon-fibre polyamide-based composite hip stem, the Exeter hip stem (Stryker, Mahwah, NJ, USA), and the Omnifit Eon (Stryker, Mahwah, NJ, USA). A virtual axial load of 3 kN was applied to the FE model. Strain and stress distributions were computed. Experimentally, the three hip stems had their distal portions rigidly mounted and had strain gauges placed along the surface at 3 medial and 3 lateral locations. Axial loads of 3 kN were applied. Measurements of axial stiffness and strain were taken and compared to FE analysis. The overall linear correlation between FE model versus experimental strains showed reasonable results for the lines-of-best-fit for the Composite (Pearson R(2)=0.69, slope=0.82), Exeter (Pearson R(2)=0.78, slope=0.59), and Omnifit (Pearson R(2)=0.66, slope=0.45), with some divergence for the most distal strain locations. From FE analysis, the von Mises stress range for the Composite stem was much lower than that in the Omnifit and Exeter implants by 200% and 45%, respectively. The preliminary experiments showed that the Composite stem stiffness (1982 N/mm) was lower than the metallic hip stem stiffnesses (Exeter, 2460 N/mm; Omnifit, 2543 N/mm). This is the first assessment of stress, strain, and stiffness of the CF/PA12 carbon-fibre hip stem compared to standard commercially-available devices.

  18. Report on von Willebrand Disease in Malaysia

    PubMed Central

    Periayah, Mercy Halleluyah; Halim, Ahmad Sukari; Saad, Arman Zaharil Mat; Yaacob, Nik Soriani; Karim, Faraizah Abdul

    2016-01-01

    BACKGROUND: Von Willebrand disease (vWD) is an inherited hemostatic disorder that affects the hemostasis pathway. The worldwide prevalence of vWD is estimated to be 1% of the general population but only 0.002% in Malaysia. AIM: Our present paper has been written to disclose the statistical counts on the number of vWD cases reported from 2011 to 2013. MATERIAL AND METHODS: This article is based on sociodemographic data, diagnoses and laboratory findings of vWD in Malaysia. A total of 92 patients were reported to have vWD in Malaysia from 2011 to 2013. RESULTS: Sociodemographic-analysis revealed that 60% were females, 63% were of the Malay ethnicity, 41.3% were in the 19-44 year old age group and 15.2% were from Sabah, with the East region having the highest registered number of vWD cases. In Malaysia, most patients are predominately affected by vWD type 1 (77.2%). Factor 8, von Willebrand factor: Antigen and vWF: Collagen-Binding was the strongest determinants in the laboratory profiles of vWD. CONCLUSION: This report has been done with great interest to provide an immense contribution from Malaysia, by revealing the statistical counts on vWD from 2011-2013. PMID:27275342

  19. Molecular diagnosis of von Willebrand disease.

    PubMed

    Baronciani, L; Goodeve, A; Peyvandi, F

    2017-03-01

    The role of molecular characterization in the diagnosis of von Willebrand disease (VWD) is not essential if the patients have been extensively investigated using phenotypic analysis. On the other hand, if some of these phenotype assays are not available, the identification of the mutation causing the disease could be crucial for an accurate diagnosis. Nevertheless, there are several reasons for performing molecular analysis in patients phenotypically well characterized, e.g. to identify the mutation causing VWD can be useful for patients and their family members when prenatal diagnosis is required (type 3 or severe type 2). In this manuscript, we report the techniques used for the molecular characterization of suspected VWD patients. We describe the use of online von Willebrand factor database and online single nucleotide variation databases, the former to verify whether a candidate mutation has been previously identified in other VWD patients and the latter to ascertain whether a putative mutation has been reported earlier in healthy individuals. We listed the available in silico analysis tools, to determine the predicted pathogenicity of a sequence variant and to establish its possible negative effect on the normal splicing process. We also report the strategy that can be used to identify VWD type 2 patients' mutations in subjects who have been fully characterized using the phenotype assays.

  20. Approximate von Neumann entropy for directed graphs.

    PubMed

    Ye, Cheng; Wilson, Richard C; Comin, César H; Costa, Luciano da F; Hancock, Edwin R

    2014-05-01

    In this paper, we develop an entropy measure for assessing the structural complexity of directed graphs. Although there are many existing alternative measures for quantifying the structural properties of undirected graphs, there are relatively few corresponding measures for directed graphs. To fill this gap in the literature, we explore an alternative technique that is applicable to directed graphs. We commence by using Chung's generalization of the Laplacian of a directed graph to extend the computation of von Neumann entropy from undirected to directed graphs. We provide a simplified form of the entropy which can be expressed in terms of simple node in-degree and out-degree statistics. Moreover, we find approximate forms of the von Neumann entropy that apply to both weakly and strongly directed graphs, and that can be used to characterize network structure. We illustrate the usefulness of these simplified entropy forms defined in this paper on both artificial and real-world data sets, including structures from protein databases and high energy physics theory citation networks.

  1. Compassionate community networks: supporting home dying.

    PubMed

    Abel, Julian; Bowra, Jon; Walter, Tony; Howarth, Glennys

    2011-09-01

    How may communities be mobilised to help someone dying at home? This conceptual article outlines the thinking behind an innovative compassionate community project being developed at Weston-super-Mare, UK. In this project, a health professional mentors the dying person and their carer to identify and match: (a) the tasks that need to be done and (b) the members of their social network who might help with these tasks. Network members may subsequently join a local volunteer force to assist others who are network poor. Performing practical tasks may be more acceptable to some family, friends and neighbours than having to engage in a conversation about dying, and provides a familiarity with dying that is often lacking in modern societies, so in this model, behavioural change precedes attitudinal change. The scheme rejects a service delivery model of care in favour of a community development model, but differs from community development schemes in which the mentor is a volunteer rather than a health professional, and also from those approaches that strive to build community capacity before any one individual dying person is helped. The pros and cons of each approach are discussed. There is a need for evaluation of this and similar schemes, and for basic research into naturally occurring resource mobilisation at the end of life.

  2. The silicone breast implant controversy.

    PubMed

    Guerette, P H

    1995-02-01

    Feminists call it objectification. Consumer advocates call it victimization. Medical personnel call it augmentation. Women, implantation. Whatever the term, media hype and the increasing number of lawsuits against U.S. manufacturers of silicone breast implants has caused widespread concern among women and raised serious questions about the long term health risks and safety of breast implant devices.

  3. Das Blüte-Bestäuber-Netz auf Brachflächen : biozönologische Untersuchung zur Bedeutung von Brachen in einer intensiv genutzten Agrarlandschaft

    NASA Astrophysics Data System (ADS)

    Hahn, Robert

    2002-11-01

    In der vorliegenden Dissertation wird die Bedeutung von Brachen für Artenvielfalt und Stabilität von Blüte-Bestäuber-Nahrungsnetzen in agrarisch genutzten Landschaften anhand ausgewählter blütenbesuchender Insektengruppen (Syrphidae, Lepidoptera) untersucht. Die Freilandarbeiten fanden von 1998-2000 im Raum der Feldberger Seenlandschaft, Mecklenburg-Vorpommern, statt. Es werden die beiden Hauptnahrungsquellen Nektar und Pollen betrachtet, dabei fanden Untersuchungen zur Intensität der Blüte-Bestäuber-Interaktion auf Stilllegungsflächen, zum flächenbezogenen quantitativen Nektarangebot im Jahresverlauf, zur individuellen Pollennutzung bei Syrphiden und zur Breite und Überlappung der Nahrungsnischen bei den dominanten Arten Episyrphus balteatus, Metasyrphus corollae, Syritta pipiens und Sphaerophoria scripta statt. Im Ergebnis zeigt sich eine hohe Bedeutung der Brachflächen für die Stabilität des Blüte-Bestäuber-Netzes, während die Diversität von anderen, eher landschaftsbezogenen Faktoren abhängig ist. This dissertation examines the importance of fallow land for the diversity and stability of pollination webs in agricultural landscapes as exemplified by selected groups of anthophilous insects (syrphidae and lepidoptera). The field studies were carried out between 1998 and 2000 in the Feldberg lakeland area in the north-east German State of Mecklenburg-Western Pomerania. Observations were made of nectar and pollen as the two main sources of food. Studies were conducted into the intensity of plant-pollinator interaction in set-aside areas, the site-specific quantity of nectar available during the vegetation period and the individual pollen intake of syrphid flies. Different methods were employed to establish the breadth of the trophic niches among the predominant species (Episyrphus balteatus, Metasyrphus corollae, Syritta pipiens and Sphaerophoria scripta) and the extent to which they overlapped. The studies showed that, while fallow land is very

  4. Semiconductor Ion Implanters

    NASA Astrophysics Data System (ADS)

    MacKinnon, Barry A.; Ruffell, John P.

    2011-06-01

    In 1953 the Raytheon CK722 transistor was priced at 7.60. Based upon this, an Intel Xeon Quad Core processor containing 820,000,000 transistors should list at 6.2 billion! Particle accelerator technology plays an important part in the remarkable story of why that Intel product can be purchased today for a few hundred dollars. Most people of the mid twentieth century would be astonished at the ubiquity of semiconductors in the products we now buy and use every day. Though relatively expensive in the nineteen fifties they now exist in a wide range of items from high-end multicore microprocessors like the Intel product to disposable items containing `only' hundreds or thousands like RFID chips and talking greeting cards. This historical development has been fueled by continuous advancement of the several individual technologies involved in the production of semiconductor devices including Ion Implantation and the charged particle beamlines at the heart of implant machines. In the course of its 40 year development, the worldwide implanter industry has reached annual sales levels around 2B, installed thousands of dedicated machines and directly employs thousands of workers. It represents in all these measures, as much and possibly more than any other industrial application of particle accelerator technology. This presentation discusses the history of implanter development. It touches on some of the people involved and on some of the developmental changes and challenges imposed as the requirements of the semiconductor industry evolved.

  5. Semiconductor Ion Implanters

    SciTech Connect

    MacKinnon, Barry A.; Ruffell, John P.

    2011-06-01

    In 1953 the Raytheon CK722 transistor was priced at $7.60. Based upon this, an Intel Xeon Quad Core processor containing 820,000,000 transistors should list at $6.2 billion. Particle accelerator technology plays an important part in the remarkable story of why that Intel product can be purchased today for a few hundred dollars. Most people of the mid twentieth century would be astonished at the ubiquity of semiconductors in the products we now buy and use every day. Though relatively expensive in the nineteen fifties they now exist in a wide range of items from high-end multicore microprocessors like the Intel product to disposable items containing 'only' hundreds or thousands like RFID chips and talking greeting cards. This historical development has been fueled by continuous advancement of the several individual technologies involved in the production of semiconductor devices including Ion Implantation and the charged particle beamlines at the heart of implant machines. In the course of its 40 year development, the worldwide implanter industry has reached annual sales levels around $2B, installed thousands of dedicated machines and directly employs thousands of workers. It represents in all these measures, as much and possibly more than any other industrial application of particle accelerator technology. This presentation discusses the history of implanter development. It touches on some of the people involved and on some of the developmental changes and challenges imposed as the requirements of the semiconductor industry evolved.

  6. Cochlear Implantation in Neurobrucellosis

    PubMed Central

    Bajin, Münir Demir; Savaş, Özden; Aslan, Filiz; Sennaroğlu, Levent

    2016-01-01

    Background: Neurobrucellosis is a disease consisting of a wide spectrum of complications such as peripheral neuropathy, cranial nerve involvement, ataxia, meningeal irritation, paraplegia, seizures, coma, and even death. The vestibulocochlear nerve seems to be the most commonly affected cranial nerve (10%). We present a patient with neurobrucellosis whose auditory perception and speech intelligibility skill performances improved after cochlear implantation. Case Report: A 35 year-old woman was admitted to another hospital 2 years ago with the symptoms of headache, nausea, and altered consciousness, who was finally diagnosed with neurobrucellosis. She developed bilateral profound sensorineural hearing loss during the following 6 months. There was no benefit of using hearing aids. After successful treatment of her illness, she was found to be suitable for cochlear implantation. After the operation, her auditory perception skills improved significantly with a Categories of Auditory Performance (CAP) score of 5. According to clinical observations and her family members’ statements, her Speech Intelligibility Rating (SIR) score was 3. Her speech intelligibility skills are still improving. Conclusion: Our case report represents the second case of hearing rehabilitation with cochlear implantation after neurobrucellosis. Cochlear implantation is a cost-effective and time-proven successful intervention in post-lingual adult patients with sensorineural hearing loss. Early timing of the surgery after appropriate treatment of meningitis helps the patient to achieve better postoperative results. PMID:26966626

  7. Remote actuated valve implant

    DOEpatents

    McKnight, Timothy E; Johnson, Anthony; Moise, Jr., Kenneth J; Ericson, Milton Nance; Baba, Justin S; Wilgen, John B; Evans, III, Boyd McCutchen

    2014-02-25

    Valve implant systems positionable within a flow passage, the systems having an inlet, an outlet, and a remotely activatable valve between the inlet and outlet, with the valves being operable to provide intermittent occlusion of the flow path. A remote field is applied to provide thermal or magnetic activation of the valves.

  8. Implantable Drug Dispenser

    NASA Technical Reports Server (NTRS)

    Collins, E. R. J.

    1983-01-01

    Drugs such as insulin are injected as needed directly into bloodstream by compact implantable dispensing unit. Two vapor cavities produce opposing forces on drug-chamber diaphragm. Heaters in cavities allow control of direction and rate of motion of bellows. Dispensing capsule fitted with coil so batteries can be recharged by induction.

  9. Practicing implant dentistry profitably.

    PubMed

    Stump, G; Adams, M; Alwan, M

    1997-03-01

    The success of dental implants has opened up countless treatment possibilities for restorative dentists to offer to their patients. Just as our clinical paradigms have had to change because of this new technology, so too must our paradigms concerning the way we communicate with our patients change if we are to get them to say "yes" to treatment that we know that they need. Success in clinical treatment using implants requires a systematic approach. A systematic approach to communicating with your patients will allow you to have the same high degree of success with treatment acceptance that is possible with dental implants. The key to the systems we have discussed is Relationship Centered Care. A relationship is fostered and enhanced through a Comprehensive Examination Process, a structured Consultation Process utilizing the influencing process and Financial Arrangements that allow the patient to receive what they want while the office maintains the profitability that it needs. A system for calculating rational fees can be utilized that allows the practice to have control over an area that traditionally was controlled by anecdotal factors. The Pride Institute has developed this material and is presenting it to the profession so that restorative dentists can truly practice implant dentistry profitably.

  10. Killing, letting die and moral perception.

    PubMed

    Gillett, Grant

    1994-10-01

    There are a number of arguments that purport to show, in general terms, that there is no difference between killing and letting die. These are used to justify active euthanasia on the basis of the reasons given for allowing patients to die. I argue that the general and abstract arguments fail to take account of the complex and particular situations which are found in the care of those with terminal illness. When in such situations, there are perceptions and intuitions available that do not easily find propositional form but lead most of those whose practice is in the care of the dying to resist active euthanasia. I make a plea for their intuitions to be heeded above the sterile voice of abstract premises and arguments by examining the completeness of the outline form of the pro-euthanasia argument. In doing so, I make use of Nussbaum's discussion of moral perception and general claims to be found in the literature of moral particularism.

  11. Effect of implant design on initial stability of tapered implants.

    PubMed

    Chong, Linus; Khocht, Ahmed; Suzuki, Jon B; Gaughan, John

    2009-01-01

    Implant design is one of the parameters for achieving successful primary stability. This study aims to examine the effect of a self-tapping blades implant design on initial stability in tapered implants. Polyurethane blocks of different densities were used to simulate different bone densities. The two different implant designs included one with self-tapping blades and one without self-tapping blades. Implants were placed at 3 different depths: apical third, middle third, and fully inserted at 3 different densities of polyurethane blocks. A resonance frequency (RF) analyzer was then used to measure stability of the implants. Repeated-measures analysis of variance was used to examine the effect of implant design, insertion depth, and block density on RF. Analysis of covariance was used to examine the strength of association between RF and the aforementioned factors. In both medium-density (P = .017) and high-density (P = .002) blocks, fully inserted non-self-tapping implants showed higher initial stability than self-tapping implants. No differences were noted between the 2 implant designs that were not fully inserted. The highest strength of association was with insertion depth (standardized beta [std beta] = -0.60, P = .0001), followed by block density (std beta = -0.15, P = .0002). Implant design showed a weak association (std beta = -0.07, P = .09). In conclusion, fully inserted implants without self-tapping blades have higher initial stability than implants with self-tapping blades. However, the association strength between implant design and initial stability is less relevant than other factors, such as insertion depth and block density. Thus, if bone quality and quantity are optimal, they may compensate for design inadequacy.

  12. CAE Based Die Face Engineering Development to Contribute to the Revitalization of the Tool & Die Industry

    NASA Astrophysics Data System (ADS)

    Tang, Arthur; Lee, Wing C.; St. Pierre, Shawn; He, Jeanne; Liu, Kesu; Chen, Chin C.

    2005-08-01

    Over the past two decades, the Computer Aided Engineering (CAE) tools have emerged as one of the most important engineering tools in various industries, due to its flexibility and accuracy in prediction. Nowadays, CAE tools are widely used in the sheet metal forming industry to predict the forming feasibility of a wide variety of complex components, ranging from aerospace and automotive components to household products. As the demand of CAE based formability accelerates, the need for a robust and streamlined die face engineering tool becomes more crucial, especially in the early stage when the tooling layout is not available, but a product design decision must be made. Ability to generate blank, binder and addendum surfaces with an appropriate layout of Drawbead, Punch Opening Line, Trim Line are the primary features and functions of a CAE based die face engineering tool. Once the die face layout is ready, a formability study should be followed to verify the die face layout is adequate to produce a formable part. If successful, the established die face surface should be exported back to the CAD/CAM environment to speed up the tooling and manufacturing design process with confidence that this particular part is formable with this given die face. With a CAE tool as described above, the tool & die industry will be greatly impacted as the processes will enable the bypass of hardware try-out and shorten the overall vehicle production timing. The trend has shown that OEMs and first tiers will source to low cost producers in the world which will have a negative impact to the traditional tool & die makers in the developed countries. CAE based tool as described should be adopted, along with many other solutions, in order to maintain efficiency of producing high quality product and meeting time-to-market requirements. This paper will describe how a CAE based die face engineering (DFE) tool could be further developed to enable the traditional tool & die makers to meet the

  13. [Allergic reactions to implant materials].

    PubMed

    Thomas, P

    2003-01-01

    The extent of the immune response upon implantation of metallic devices depends on the individual reactivity and on material characteristics. If specific T-cellular sensitization occurs or an allergy to metal preexists, hypersensitive reactions to implant components may develop. They include eczema, impaired wound healing, and sterile osteomyelitis. The existence of allergy-induced implant loosening is still an open question. Further improvement of clinical allergological diagnostics, better understanding of peri-implantar immune reactions, and interdisciplinary collection of epidemiological data concerning allergy to implants will contribute to a better knowledge about tolerance of implant material in humans.

  14. Prosthodontic management of implant therapy.

    PubMed

    Thalji, Ghadeer; Bryington, Matthew; De Kok, Ingeborg J; Cooper, Lyndon F

    2014-01-01

    Implant-supported dental restorations can be screw-retained, cement-retained, or a combination of both, whereby a metal superstructure is screwed to the implants and crowns are individually cemented to the metal frame. Each treatment modality has advantages and disadvantages. The use of computer-aided design/computer-assisted manufacture technologies for the manufacture of implant superstructures has proved to be advantageous in the quality of materials, precision of the milled superstructures, and passive fit. Maintenance and recall evaluations are an essential component of implant therapy. The longevity of implant restorations is limited by their biological and prosthetic maintenance requirements.

  15. [The search for "od." Karl Ludwig Freiheer von Reichenbach (1788-1869) and Karl Wilhelm Mayrhofer (1806-1853), two joined against Justus von Liebig].

    PubMed

    Habacher, M

    1980-05-01

    The author describes the controversy between Justus von Liebig on one side and Reichenbach and Mayrhofer on the other side. It is a controversy about problems of science and medicine which are characteristic for the late 18th and the first half of the 19th century, when Mesmerism and similar ideas of occultic and comparative phenomenona were discussed and often refused as being "not scientific". Justus von Liebig and Karl Ludwig Freiherr von Reichenbach were both chemists, both interested in scientific progress and working in this field. They were friends in the years 1830 to 1848. But later on this friendship ended when Reichenbach--who in the mean time moved to Vienna--became more and more interested in phenomenons seen by sensitive persons concerning effects of light. Although Reichenbach himself was not able to recognize the phenomenons he was sure that other persons had this ability. He had the impression that there is a special force floating through the universe, and this force he called "od". Liebig, who was not able to follow this theory and rejected it has speculation, turned against Reichenbach in 1852-3. So the controversy began and their old friendship came to an end. Reichenbach's theory of the "od", characteristic for the time of the romanticism and leading back to Mesmerism was accepted and supported by the Austrian physician Dr. Karl Wilhelm Mayrhofer who had aroused his interest by describing similar phenomenos some of this patients had. The letters of both men, the chemist and the doctor, which are well preserved (Technical Museum of Vienna) and discussed here, give a good impression of Reichenbach's ideas concerning his theory of the "od" and his philosophical ideas. As Reichenbach tried to find a philosophy corresponding to his theory and as he meant to have found this in the philosophy of Friedrich Eduard Beneke his remarks in those letters give a good information about Beneke's discussion of Reichenbach's theory. Mayrhofer, on the other hand

  16. Effects of tissue-engineered articular disc implants on the biomechanical loading of the human temporomandibular joint in a three-dimensional finite element model.

    PubMed

    Al-Sukhun, Jehad; Ashammakhi, Nureddin; Penttila, Heikki

    2007-07-01

    The purpose of this study was to evaluate biomechanical loading of the temporomandibular joint when using a biodegradable laminate implant to replace the articular disc and to test the hypothesis that the use of the implant reduces stress distribution in the condyle, implant, and glenoid fossa. A finite element model of a female human mandible, including the temporomandibular joint, which had two standard endosseous implants inserted bilaterally in the premolar region, was constructed from computed tomography scan images using a commercially available finite element software. The disc, condyle, and glenoid fossa were arbitrarily divided into five regions: the anterior, posterior, medial, lateral, and central. The disc was then replaced with a poly-L/DL-lactide biodegradable laminate. The finite element model was then used to predict principal and Von Mises stresses. The use of poly-L/DL-lactide implant resulted in remarkable reduction in Von Mises stresses (approximately threefold) in the anterior, central, and medial regions of the mandibular condyle in comparison with slight to moderate stress reductions in the corresponding regions of the implant and glenoid fossa. The mandibular condyle also demonstrated the largest total displacement in all directions followed by the implant and glenoid fossa. The use of an alloplastic implant such as the bioresorbable, poly-L/DL-lactide laminate to replace the articular disc reduces loading of the mandibular condyle rather than the implant and glenoid fossa. These findings lead to support the hypothesis that the mandibular condyle more likely functions as a shock absorber than the disc. The use of bioresorbable laminate implants might prove an efficient technique to replace the articular disc and promote normal function of the temporomandibular joint.

  17. Die Arbeitsunfähigkeit in der Statistik der GKV

    NASA Astrophysics Data System (ADS)

    Busch, Klaus

    Der vorliegende Beitrag gibt anhand der Statistiken des Bundesministeriums für Gesundheit (BMG) einen Überblick über die Arbeitsunfähigkeitsdaten der Gesetzlichen Krankenkassen (GKV). Zunächst werden die Arbeitsunfähigkeitsstatistiken der Krankenkassen und die Erfassung der Arbeitsunfähigkeit erläutert. Hiernach wird auf die Entwicklung der Fehlzeiten auf GKV-Ebene eingegangen. Ebenfalls wird Bezug auf die Unterschiede der Fehlzeiten zwischen den verschiedenen Kassen genommen.

  18. Two novel anti-von Willebrand factor monoclonal antibodies.

    PubMed

    Spadafora-Ferreira, M; Lopes, A A; Coelho, V; Guilherme, L; Kalil, J

    2000-01-15

    Von Willebrand Factor is a multimer produced by endothelial cells and megakaryocytes, being stored in intracellular organelles, such as the Weibel-Palade bodies and alpha-granules in endothelial cells and platelets, respectively. This molecule acts as a carrier protein for factor VIIIc, involved in the intrinsic pathway of blood coagulation maintaining its stability in circulation. Von Willebrand Factor also plays an important role in platelet aggregation and adhesion to injured vessel wall. It interacts with platelets through two distinct glycoproteins, GPIb and GPIIb/IIIa. We raised two monoclonal antibodies, ECA-3 and ECA-4, against human umbilical vascular endothelial cells that recognize and immunoprecipitate von Willebrand Factor. Interestingly, ECA-4 monoclonal antibody is able to completely inhibit platelet agglutination induced by ristocetin, suggesting that it binds to von Willebrand Factor close to platelet GPIb binding site. The use of monoclonal antibodies to identify von Willebrand Factor binding regions to factor VIII or platelets has been reported by others. In pulmonary hypertension, abnormalities have been detected on the multimeric structure of the molecule as well as on its proteolytic fragments, by using monoclonal antibodies. Moreover, monoclonal antibodies raised against specific regions of von Willebrand Factor molecule may allow studies of functional abnormalities of this protein in inherited and acquired disorders like subtypes of von Willebrand's disease.

  19. Impression techniques for implant dentistry.

    PubMed

    Chee, W; Jivraj, S

    2006-10-07

    The object of making an impression in implant dentistry is to accurately relate an analogue of the implant or implant abutment to the other structures in the dental arch. This is affected by use of an impression coping which is attached to the implant or implant abutment. This impression coping is incorporated in an impression - much as a metal framework is 'picked up' in a remount impression for fixed prosthodontics. With implant copings the coping is usually attached to the implant or abutment with screws. The impression material used is usually an elastomeric impression material; the two types most widely used and shown to be the most appropriate are polyether and polyvinyl siloxane impression materials.

  20. Engineered porous metals for implants

    NASA Astrophysics Data System (ADS)

    Vamsi Krishna, B.; Xue, Weichang; Bose, Susmita; Bandyopadhyay, Amit

    2008-05-01

    Interest is significant in patient-specific implants with the possibility of guided tissue regeneration, particularly for load-bearing implants. For such implants to succeed, novel design approaches and fabrication technologies that can achieve balanced mechanical and functional performance in the implants are necessary. This article is focused on porous load-bearing implants with tailored micro-as well as macrostructures using laser-engineered net shaping (LENS™), a solid freeform fabrication or rapid prototyping technique that can be used to manufacture patient-specific implants. This review provides an insight into LENS, some properties of porous metals, and the potential applications of this process to fabricate unitized structures which can eliminate longstanding challenges in load-bearing implants to increase their in-vivo lifetime, such as in a total hip prosthesis.

  1. [Von Willebrand disease in the Netherlands: the WiN study].

    PubMed

    Sanders, Yvonne V; de Wee, Eva M; Meijer, Karina; Eikenboom, J; van der Bom, Jeroen G; Fijnvandraat, C J Karin; Laros-van Gorkom, Britta A P; Cnossen, Marjon H; Mauser-Bunschoten, Evelien P; Leebeek, Frank W G

    2014-01-01

    Von Willebrand disease is the most common inherited bleeding disorder and is characterised by mucocutaneous bleeding. Von Willebrand disease is caused by reduced levels or reduced function of von Willebrand factor. Depending on the cause, von Willebrand disease is distinguished into various types with their own characteristics and treatment options. The frequency and severity of bleeding in patients with von Willebrand disease is strongly determined by von Willebrand factor levels, factor VIII levels and the type of von Willebrand disease. Eighty-five percent of all adult females with von Willebrand disease reports menorrhagia. A high percentage have postpartum excessive blood loss (37% of all deliveries). The quality of life is reduced in patients with von Willebrand disease. Patients with von Willebrand disease have a reduced risk of arterial thrombosis such as a myocardial or cerebral infarction.

  2. Interactions of von Willebrand factor and ADAMTS13 in von Willebrand disease and thrombotic thrombocytopenic purpura.

    PubMed

    Budde, U; Schneppenheim, R

    2014-01-01

    The function of von Willebrand factor (VWF), a huge multimeric protein and a key factor in platelet dependent primary haemostasis, is regulated by its specific protease ADAMTS13. The ADAMTS13 dependent degradation of VWF to its proteolytic fragments can be visualized as a characteristic so-called triplet structure of individual VWF oligomers by multimer analysis. Lack of VWF high molecular weight multimers (VWF-HMWM) or their pathologically enhanced degradation underlies a particular type of von Willebrand disease, VWD type 2A with a significant bleeding tendency, and may also be observed in acquired von Willebrand syndrome due to cardiovascular disease. In these conditions multimer analysis is an obligatory and powerful tool for diagnosis of VWD. The opposite condition, the persistence of ultralarge VWF (UL-VWF) multimers may cause the microangiopathic life-threatening disorder thrombotic thrombocytopenic purpura (TTP). During the course of active TTP, UL-VWF is consumed in the hyaline thrombi formed in the microvasculature which will ultimately result in the loss of UL-VWF and VWF-HMWM. Therefore, VWF multimer analysis is not a valid tool to diagnose TTP in the active phase of disease but may be helpful for the diagnosis of TTP patients in remission.

  3. Valence bond and von Neumann entanglement entropy in Heisenberg ladders.

    PubMed

    Kallin, Ann B; González, Iván; Hastings, Matthew B; Melko, Roger G

    2009-09-11

    We present a direct comparison of the recently proposed valence bond entanglement entropy and the von Neumann entanglement entropy on spin-1/2 Heisenberg systems using quantum Monte Carlo and density-matrix renormalization group simulations. For one-dimensional chains we show that the valence bond entropy can be either less or greater than the von Neumann entropy; hence, it cannot provide a bound on the latter. On ladder geometries, simulations with up to seven legs are sufficient to indicate that the von Neumann entropy in two dimensions obeys an area law, even though the valence bond entanglement entropy has a multiplicative logarithmic correction.

  4. Verfügbarkeit von Montagesystemen

    NASA Astrophysics Data System (ADS)

    Wiendahl, Hans-Peter; Hegenscheidt, Matthias

    Im Vergleich zur Teileherstellung wird bei einer Montageanlage eine ungleich größere Anzahl verschiedener Teile in verketteten Stationen mit Taktzeiten im Sekundenbereich verarbeitet. Weiterhin sind viele unterschiedliche Füge- and Handhabungsfunktionen zur Montage and Prüfung der teilweise empfindlichen Teile erforderlich. Und schließlich erfordert die Verkettung and Speicherung der Teile and Zwischenprodukte umfangreiche Transport- and Speichereinrichtungen. In der Praxis treten daher vergleichsweise oft Unterbrechungen unterschiedlicher Dauer auf.

  5. Effect of Die Strength and Work Piece Strength on the Wear of Hot Forging Dies

    NASA Astrophysics Data System (ADS)

    Levy, B. S.; Van Tyne, C. J.

    2015-01-01

    The effect of the strength ratio extracted from an Archard model for wear is used to describe the wear rates expected in hot forging dies. In the current study, the strength ratio is the strength of the hot forging die to the strength of the work piece. Three hot forging die steels are evaluated. The three die steels are FX, 2714, and WF. To determine the strength of the forging die, a continuous function has been developed that describes the yield strength of three die steels for temperatures from 600 to 700 °C and for times up to 20 h (i.e., tempering times of up to 20 h). The work piece material is assumed to be AISI 1045. Based on the analysis, the wear resistance of WF should be superior and FX should be slightly better than 2714. Decreasing the forging temperature increases the strength ratio, because the strength of the die surface increases faster than the flow strength of AISI 1045. The increase in the strength ratio indicates a decrease in the expected wear rate.

  6. Investigation of Die Stress Profiles during Powder Compaction using Instrumented Die

    SciTech Connect

    Hong, Sung-tae; Hovanski, Yuri; Lavender, Curt A.; Weil, K. Scott

    2008-06-01

    The radial stress profile in a cylindrical die during compaction of titanium (Ti) powder was investigated by experiments. The concept of an instrumented die was extended to design an enhanced instrumented die. Custom-made strain gage pins were used to measure the radial stress during powder compaction. The test fixture was designed to simulate double-action pressing. The measured die stress profile for Ti powder was compared with that for a commercially available iron (Fe) powder. The stress history shows that an appreciable residual stress remains in the die in the radial direction after the axial compaction stress is removed from the powder. Furthermore, the radial stress profile in the die, while under maximum axial compaction stress, is more uniform across the height of the Fe compact than that of the Ti compact. In addition, the residual stress profile in the die in the radial direction reduces symmetrically in both directions beyond the height of the compact for both powders. Finally, the Ti powder shows a significantly higher frictional coefficient at the maximum axial compaction stress, and consequently a higher maximum axial ejection stress than the Fe powder.

  7. Evaluation of master cast techniques for multiple abutment implant prostheses.

    PubMed

    Vigolo, P; Millstein, P L

    1993-01-01

    This study compared the accuracy of three techniques used to fabricate master casts for implant prostheses. A metal model with six implants and standard abutments and a matching template were fabricated. Impressions of the model were made in Impregum and cast in Die Keen. The casts were divided into three groups of 15 casts: group A--solid casts; group B--Pindex; and group C--Zeiser system. Each cast was visually evaluated for fit of the template. Positional accuracy of the abutments was numerically assessed using an optical comparator. Visual analysis showed that only casts sectioned with the Zeiser system allowed a passive fit of the template. Statistical analysis of numerical findings indicated that casts made with the Zeiser system were significantly more accurate than solid casts, which in turn were more accurate than those made with the Pindex system.

  8. Deactivation of Pacemakers and Implantable Cardioverter-Defibrillators

    PubMed Central

    Kramer, Daniel B.; Mitchell, Susan L.; Brock, Dan W.

    2013-01-01

    Cardiac implantable electrical devices (CIEDs), including pacemakers (PMs) and implantable cardioverter-defibrillators (ICDs), are the most effective treatment for life-threatening arrhythmias. Patients or their surrogates may request device deactivation to avoid prolongation of the dying process or in other settings, such as after device-related complications or with changes in their health care goals. Despite published guidelines outlining theoretical and practical aspects of this common clinical scenario, significant uncertainty remains for both patients and health care providers regarding the ethical and legal status of CIED deactivation. This review outlines the ethical and legal principles supporting CIED deactivation at patients’ request, centered upon patient autonomy and authority over their own medical treatment. The empirical literature describing stakeholder views and experiences surrounding CIED deactivation is described, along with lessons for future research and practice guidance surrounding the care of patients with CIEDs. PMID:23217433

  9. Hermann von Helmholtz and his students

    NASA Astrophysics Data System (ADS)

    Mulligan, Joseph F.

    1989-01-01

    During the years 1871-1888, when Hermann von Helmholtz was professor of physics at the University of Berlin, physicists from all over the world flocked to Berlin to study and do research with him. Among these were the German physicists Max Planck, Heinrich Kayser, Eugen Goldstein, Wilhelm Wien, and Heinrich Hertz, and Americans Henry Rowland, A. A. Michelson, and Michael Pupin. Examples of Helmholtz's scientific and personal interactions with these students and research associates show why he is justly considered the outstanding physics mentor of the 19th century. Both his ideas and his students played a major role in the development of physics in the late 19th and early 20th centuries.

  10. Von Economo neurons in the elephant brain.

    PubMed

    Hakeem, Atiya Y; Sherwood, Chet C; Bonar, Christopher J; Butti, Camilla; Hof, Patrick R; Allman, John M

    2009-02-01

    Von Economo neurons (VENs), previously found in humans, all of the great ape species, and four cetacean species, are also present in African and Indian elephants. The VENs in the elephant are primarily found in similar locations to those in the other species. They are most abundant in the frontoinsular cortex (area FI) and are also present at lower density in the anterior cingulate cortex. Additionally, they are found in a dorsolateral prefrontal area and less abundantly in the region of the frontal pole. The VEN morphology appears to have arisen independently in hominids, cetaceans, and elephants, and may reflect a specialization for the rapid transmission of crucial social information in very large brains.

  11. Johann von Lamont: A Pioneer in Geomagnetism

    NASA Astrophysics Data System (ADS)

    Soffel, Heinrich

    2006-06-01

    The 200th birthday of John Lamont (1805-1879, Figure 1), a pioneer in the study of geomagnetism, was marked on 13 December 2005. Lamont founded the Munich Geomagnetic Observatory in 1840 and was a member of the group of scientists including Carl Friedrich Gauss, Alexander von Humboldt, Eduard Sabine, Jonas Angstrøm, Humphret Lloyd, Adolf Kupffer, Karl Kreil, and Adolphe Quetelet who composed the Göttingen Magnetic Union. They organized an international network of geomagnetic observatories [Barraclough et al., 1992]. The present knowledge of the geomagnetic field and its secular variation is largely based on the data collected by the global network of geomagnetic observatories during the last 170 years. Lamont's talents and his dedication and enthusiasm for discovery are reflected in the depth and scope of his contributions to a broad variety of natural sciences such as astronomy, meteorology, geomagnetism, and geodesy. However, this article just touches on his merits in geomagnetism.

  12. Johann Philipp von Wurzelbau (1651-1725)

    NASA Astrophysics Data System (ADS)

    Gaab, Hans

    During the turn of the 17th to the 18th century, Johann Philipp von Wurzelbau was the best-known astronomer in Nuremberg. He was a trained merchant, who busied himself in his free hours with astronomy. In the 1680s he became known for his accurate observations of lunar and solar eclipses. At the end of the 1680s he left his trade, and from 1691, he was completely occupied with astronomy. To that end, he constructed a small octagonal observing tower on the roof of his house at Spitzenberg 4. He took the measurement of the solar path and determined the geographical coordinates of Nuremberg. The calendar reform also played a major role in his life.

  13. A profile of silicosis cases who died.

    PubMed

    Phoon, W H

    1982-01-01

    Silicosis cases which had been notified by doctors and confirmed after investigations were followed up by the Industrial Health Division. Up to August 1981, a total of 313 persons were confirmed as having the disease. Of these, 59 had died. The majority of these 59 persons had had their silica exposure in the granite quarries. 13 had been exposed to "rubber powder" which contained a high percentage of free silica. 52 of those who died were male, and their average age at death was 60.87 years. This did not appear to be significantly shorter than their life expectancy of 65.1 years. But the average age of death for the 7 women was 58.86 years, which was much shorter than their life expectancy of 70 years. Many of the men died from causes unrelated to silicosis. But 6 of the 7 women had progressive massive fibrosis (PMF) and they apparently died of the disease or complications arising from it.

  14. Expectation and Variation with a Virtual Die

    ERIC Educational Resources Information Center

    Watson, Jane; English, Lyn

    2015-01-01

    By the time students reach the middle years they have experienced many chance activities based on dice. Common among these are rolling one die to explore the relationship of frequency and theoretical probability, and rolling two dice and summing the outcomes to consider their probabilities. Although dice may be considered overused by some, the…

  15. Stamping Die Making. 439-318/320.

    ERIC Educational Resources Information Center

    Yunke, P.; And Others

    Each unit in this curriculum guide on stamping die making contains an introduction, objectives, materials required, lessons, space for notes, figures, and diagrams. There are 29 units in this guide, dealing with the following topics: EZ-MILL programming; EZ-MILL BATT; print of punch and EZ-MILL part programming; download to Computer Numerical…

  16. Care of the Dying: A Swedish Perspective

    ERIC Educational Resources Information Center

    Feigenberg, Loma; Fulton, Robert

    1977-01-01

    This article illustrates various aspects of terminal care, and shows that rules and norms for such care do not exist today. The authors advocate the formulation of an aim for humane treatment of dying patients, and its application in a manner appropriate to Swedish medical concepts and Swedish conditions. (Author)

  17. Asymmetric Die Grows Purer Silicon Ribbon

    NASA Technical Reports Server (NTRS)

    Kalejs, J. P.; Chalmers, B.; Surek, T.

    1983-01-01

    Concentration of carbide impurities in silicon ribbon is reduced by growing crystalline ribbon with die one wall higher than other. Height difference controls shape of meniscus at liquid/crystal interface and concentrates silicon carbide impurity near one of broad faces. Opposite face is left with above-average purity. Significantly improves efficiency of solar cells made from ribbon.

  18. Ceramic for Silicon-Shaping Dies

    NASA Technical Reports Server (NTRS)

    Sekercioglu, I.; Wills, R. R.

    1982-01-01

    Silicon beryllium oxynitride (SiBON) is a promising candidate material for manufacture of shaping dies used in fabricating ribbons or sheets of silicon. It is extremely stable, resists thermal shock, and has excellent resistance to molten silicon. SiBON is a solid solution of beryllium silicate in beta-silicon nitride.

  19. The Onion and "When Legends Die."

    ERIC Educational Resources Information Center

    Bell, Loren C.

    1984-01-01

    Describes the eight layers in Thomas Black Bull's ("When the Legends Die") journey to spiritual rebirth and stresses that students can easily identify these layers and can thereby achieve a clearer understanding of the relationship between structure and meaning in fiction. (CRH)

  20. Counseling Older Persons: Careers, Retirement, Dying.

    ERIC Educational Resources Information Center

    Sinick, Daniel

    The focus of this monograph is on three areas of counseling with older clients: career counseling, retirement counseling, and counseling regarding death and dying. The portion on career counseling includes reasons older persons change careers, obstacles they are likely to face when seeking employment, myths surrounding the employability of older…

  1. Mold Die Making. 439-322/324.

    ERIC Educational Resources Information Center

    Yunke, P.; And Others

    Each unit in this curriculum guide on mold die making contains an introduction, objectives, materials required, lessons, space for notes, figures, and diagrams. There are 10 units in this guide: (1) introduction to Electrical Discharge Machining (EDM); (2) EDM principles; (3) the single pulse; (4) EDM safety; (5) electrode material; (6) electrode…

  2. [Companionship for women dying of AIDS].

    PubMed

    Gerlach, E

    1999-01-01

    This report reflects the experience of accompanying HIV-infected women during the process of dying using their curriculi vitae as examples of different modes of dealing with fatal illness. The text contains paintings of past and contemporary art concerning death and eros and poetry as a form of therapy.

  3. The Academic Study of Death and Dying.

    ERIC Educational Resources Information Center

    Amend, Edward W.

    The current study of death and dying is an example of constant change and development in academic disciplines. While the discussion of death in time of crisis is hard, if not impossible, youthful undergraduates find this topic to be of considerable interest. For them, a course can be organized effectively as a small and intimate seminar, which…

  4. Piezosurgery in implant dentistry

    PubMed Central

    Stübinger, Stefan; Stricker, Andres; Berg, Britt-Isabelle

    2015-01-01

    Piezosurgery, or the use of piezoelectric devices, is being applied increasingly in oral and maxillofacial surgery. The main advantages of this technique are precise and selective cuttings, the avoidance of thermal damage, and the preservation of soft-tissue structures. Through the application of piezoelectric surgery, implant-site preparation, bone grafting, sinus-floor elevation, edentulous ridge splitting or the lateralization of the inferior alveolar nerve are very technically feasible. This clinical overview gives a short summary of the current literature and outlines the advantages and disadvantages of piezoelectric bone surgery in implant dentistry. Overall, piezoelectric surgery is superior to other methods that utilize mechanical instruments. Handling of delicate or compromised hard- and soft-tissue conditions can be performed with less risk for the patient. With respect to current and future innovative surgical concepts, piezoelectric surgery offers a wide range of new possibilities to perform customized and minimally invasive osteotomies. PMID:26635486

  5. The sky-disk of Nebra - sun, moon and stars (German Title: Die Himmelsscheibe von Nebra - Sonne, Mond und Sterne)

    NASA Astrophysics Data System (ADS)

    Schlosser, Wolfhard

    No prehistorical find anywhere shows such a clear proof for the interest of prehistoric mankind in cosmic events as does the Nebra sky-disk. With an almost 100 percent probability, the (originally) 32 centimeter-size gold plates represent stars. According to astronomical analysis, the group of seven closely arranged plates represent the Pleiades (The Seven Sisters). Statistical research strengthens the view that the remaining 25 gold plates cannot be assigned to individual constellations, but represent the general starry night sky. Without much restriction, the two lateral arcs (added at a later time) can be assigned to those horizon regions which are accessible to the sun over the year for the geographic latitude of Saxe-Anhalt. A slight asymmetry of these arcs with respect to the center of the disk makes it possible that the upper solar limb was observed. The lower pinnate arc with an interior drawing - also a later addition - can be interpreted as the solar barque, which, because of the above-mentioned asymmetry, indicates the southern direction of the sky-disk. An investigation of the visibilities of the Pleiades for the finding spot of the Mittelberg indicates that only their last evening visibility (March 10 of our calendar) and their first morning setting (October 17) were of calendary use in the early Bronze Age. At these times, the Pleiades were found in those parts of the sky which are the domain of the young crescent shortly after new moon (March) and of the full moon (October). This would make possible a suitable assignment of the sky-disk's crescent- and round object to both these phases of the moon. The said dates describe quite well the beginning and the end of the agricultural year for the region where the sky-disk was found. Such a working hypothesis (‘rural year’) is not at all unique, but is supported by numerous peasant-rules referring to the Pleiades from antiquity up to the present time. In particular, Lithuanian peasants observed until modern times the last evening visibility and the first morning setting of the Pleiades as agricultural key-dates or omina.

  6. Identifikation und Regionalisierung von Nitratabbauprozessen in einem Grundwasserleiter - Möglichkeiten und Nutzen für die Wassergewinnung

    NASA Astrophysics Data System (ADS)

    Jesußek, Anna; Hansen, Carsten; Wilde, Siegfried

    2016-11-01

    Denitrification with pyrite or organic carbon compounds in aquifers can lead to the release of ferrous iron, sulfate and bicarbonate into the groundwater. For the water catchment, Ortheide (Emsdetten, Germany), nitrate reduction with pyrite also causes an increased well clogging with iron hydroxides in some of the wells. With the help of hydrogeochemical modelling (PhreeqC), the main processes in the aquifer of the catchment area were identified and quantified. The presence or absence of pyrite in the aquifer sediments was determined based on groundwater compositions. This allowed the regionalization of autolithotrophic denitrification in the aquifer and the distinction of so called "origin zones" of nitrate, ferrous iron and bicarbonate. Based on these zones, the comparative sensitivity of agricultural areas towards nitrate concentrations in the raw water and the clogging tendency of the wells could be estimated.

  7. Untersuchungen ueber die Kultivierung und Biologie von Trichomonas vaginalis (Investigation on Cultivation and Biology of Trichomonas vaginalis),

    DTIC Science & Technology

    Since long possible cyst formation by Trichomonas vaginalis has been discussed. According to our observations the round forms of Trichomonas ... vaginalis in relation to its biogenic surroundings. Here the biochemico-physiological relationship between Trichomonas and the fundamental biogenic...generally appear as degenerative manifestations of the cell, especially in older cultures. We tried to study analytically the biology of Trichomonas

  8. Die berufliche Weiterbildung von Grund- und Sekundarschullehrern in Japan (Further Professional Training for Elementary and Secondary School Teachers in Japan).

    ERIC Educational Resources Information Center

    Shimahara, N. Ken

    2001-01-01

    Focuses on the system of further vocational education for Japanese teachers that is based on a network of cooperation among colleagues. Demonstrates how the Japanese conception of teaching as a craft determines the professional career of teachers within elementary and secondary schooling. (CMK)

  9. Bedeutung kleinräumiger Daten für die Evaluation von Bildungsprojekten. Das Beispiel der Junior Uni Wuppertal

    NASA Astrophysics Data System (ADS)

    Makles, Anna

    2016-12-01

    The Junior University, a University for children and youth in the city of Wuppertal, offers science courses that target children and youth from all socioeconomic backgrounds. The first evaluation study done by the University of Wuppertal in 2013 aimed at examining whether the Junior University has achieved this goal. The main challenge of our analysis was to approximate missing individual information on socioeconomic status by using spatial data. Therefore, we georeferenced address information of the Junior University students and linked those results to different characteristics available for about 2800 city blocks in the city of Wuppertal. We found out that indeed the Junior University succeeds in attracting children and youth from all socioeconomic backgrounds. The results show that many of the students live in poor neighborhoods or in neighborhoods with a high share of immigrants.

  10. The breast implant controversy.

    PubMed

    Cook, R R; Harrison, M C; LeVier, R R

    1994-02-01

    The breast implant issue is a "bad news/good news" story. For many women with implants, the controversy has caused a fair degree of anxiety which may or may not be resolved as further information becomes available. It has also taken its toll on Dow Corning. Whole lines of medical products have been eliminated or are being phase out. The development of new medical applications has been terminated. As a consequence, employees have lost their jobs. What the effect will be on the biomedical industry as a whole remains to be seen (11). While silicones have been an important component in various medical devices, it is likely that other materials can be used as replacements. However, suppliers of non-silicone materials are also reevaluating their role in this market. For example, Du Pont, the nation's largest chemical company, has determined that the unpredictable and excessive costs of doing business with manufacturers of implantable medical devices no longer justifies the unrestricted sale of standard raw materials into this industry. Other companies are quietly following suit. On the up side, it is possible that the research being driven by this controversy will result in a greater understanding of the immunologic implications of xenobiotics, of the importance of nonbiased observations, of the need for ready access to valid data sets, and of the opportunity for valid scientific information to guide legal decisions. Only time will tell.

  11. [Neurotology and cochlear implants].

    PubMed

    Merchán, Miguel A

    2015-05-01

    In this review we analyse cochlear implantation in terms of the fundamental aspects of the functioning of the auditory system. Concepts concerning neuronal plasticity applied to electrical stimulation in perinatal and adult deep hypoacusis are reviewed, and the latest scientific bases that justify early implantation following screening for congenital deafness are discussed. Finally, this review aims to serve as an example of the importance of fostering the sub-specialty of neurotology in our milieu, with the aim of bridging some of the gaps between specialties and thus improving both the knowledge in the field of research on auditory pathologies and in the screening of patients. The objectives of this review, targeted above all towards specialists in the field of otorhinolaryngology, are to analyse some significant neurological foundations in order to reach a better understanding of the clinical events that condition the indications and the rehabilitation of patients with cochlear implants, as well as to use this means to foster the growth of the sub-specialty of neurotology.

  12. Electronic retinal implant surgery.

    PubMed

    MacLaren, R E

    2017-02-01

    Blindness due to outer retinal degeneration still remains largely untreatable. Photoreceptor loss removes light sensitivity, but the remaining inner retinal layers, the optic nerve, and indeed the physical structure of the eye itself may be unaffected by the degenerative processes. This provides the opportunity to restore some degree of vision with an electronic device in the subretinal space. In this lecture I will provide an overview of our experiences with the first-generation retinal implant Alpha IMS, developed by Retina Implant AG and based on the technology developed by Eberhart Zrenner as part of a multicentre clinical trial (NCT01024803). We are currently in the process of running a second NIHR-funded clinical trial to assess the next-generation device. The positive results from both studies to date indicate that the retinal implant should be included as a potential treatment for patients who are completely blind from retinitis pigmentosa. Evolution of the technology in future may provide further opportunities for earlier intervention or for other diseases.

  13. Tubo-uterine implantation.

    PubMed

    Green-armytage, V G

    1957-02-01

    After characterizing 2 types of patients presenting with tubal infertility (1 that is "as a rule overweight (the uterus is fixed (and there is easily palpable tubo-uterine pathology," and 1 that is "slim, young, intelligent and often beautiful", 12 1-sentence suggestions are made to increase the success of tubo-uterine implantations in the second type of presenting patient (because the first group has, in the author's mind, disappointing prognosis). Figures are the bulk of the document, with 3 figures demonstrating the type of operation, 3 showing the scheme of the operation, 1 figure showing a posterior view of the implanted tube in utero with a polyethylene prosthesis in situ down to the cervix, and 1 figure showing the instruments used in the operation. A few points of experience the author shares are: 1) operate immediately after a menstrual period; 2) give antibiotics prophylactically and after the procedure; 3) use a Bonney Myomectomy Clamp to elevate the uterus; 4) never use a knife or bistoury at the cornua; 5) use polyethylene rods, when available; and 6) caesarean section is the indicated delivery route after tubo-uterine implantation. Out of 38 patients with the requisite history and findings who have been operated on by this author, 14 have gone to full-term, i.e., 36.1%; 2 have aborted, giving a pregnancy rate of 42.2%, and there was 1 ectopic pregnancy.

  14. Bone Substitutes for Peri-Implant Defects of Postextraction Implants

    PubMed Central

    Santos, Pâmela Letícia; Gulinelli, Jéssica Lemos; Telles, Cristino da Silva; Betoni Júnior, Walter; Chiacchio Buchignani, Vivian; Queiroz, Thallita Pereira

    2013-01-01

    Placement of implants in fresh sockets is an alternative to try to reduce physiological resorption of alveolar ridge after tooth extraction. This surgery can be used to preserve the bone architecture and also accelerate the restorative procedure. However, the diastasis observed between bone and implant may influence osseointegration. So, autogenous bone graft and/or biomaterials have been used to fill this gap. Considering the importance of bone repair for treatment with implants placed immediately after tooth extraction, this study aimed to present a literature review about biomaterials surrounding immediate dental implants. The search included 56 articles published from 1969 to 2012. The results were based on data analysis and discussion. It was observed that implant fixation immediately after extraction is a reliable alternative to reduce the treatment length of prosthetic restoration. In general, the biomaterial should be used to increase bone/implant contact and enhance osseointegration. PMID:24454377

  15. Platelet adhesion and plasma protein adsorption control of collagen surfaces by He + ion implantation

    NASA Astrophysics Data System (ADS)

    Kurotobi, K.; Suzuki, Y.; Nakajima, H.; Suzuki, H.; Iwaki, M.

    2003-05-01

    He + ion implanted collagen-coated tubes with a fluence of 1 × 10 14 ions/cm 2 were exhibited antithrombogenicity. To investigate the mechanisms of antithrombogenicity of these samples, plasma protein adsorption assay and platelet adhesion experiments were performed. The adsorption of fibrinogen (Fg) and von Willebrand factor (vWf) was minimum on the He + ion implanted collagen with a fluence of 1 × 10 14 ions/cm 2. Platelet adhesion (using platelet rich plasma) was inhibited on the He + ion implanted collagen with a fluence of 1 × 10 14 ions/cm 2 and was accelerated on the untreated collagen and ion implanted collagen with fluences of 1 × 10 13, 1 × 10 15 and 1 × 10 16 ions/cm 2. Platelet activation with washed platelets was observed on untreated collagen and He + ion implanted collagen with a fluence of 1 × 10 14 ions/cm 2 and was inhibited with fluences of 1 × 10 13, 1 × 10 15 and 1 × 10 16 ions/cm 2. Generally, platelets can react with a specific ligand inside the collagen (GFOGER sequence). The results of platelets adhesion experiments using washed platelets indicated that there were no ligands such as GFOGER on the He + ion implanted collagen over a fluence of 1 × 10 13 ions/cm 2. On the 1 × 10 14 ions/cm 2 implanted collagen, no platelet activation was observed due to the influence of plasma proteins. From the above, it is concluded that the decrease of adsorbed Fg and vWf caused the antithrombogenicity of He + ion implanted collagen with a fluence of 1 × 10 14 ions/cm 2 and that plasma protein adsorption took an important role repairing the graft surface.

  16. Implant biomechanics in grafted sinus: a finite element analysis.

    PubMed

    Fanuscu, Mete I; Vu, Hung V; Poncelet, Bernard

    2004-01-01

    This in vitro study investigated the stress distribution in the bone surrounding an implant that is placed in a posterior edentulous maxilla with a sinus graft. The standard threaded implant and anatomy of the crestal cortical bone, cancellous bone, sinus floor cortical bone, and grafted bone were represented in the 3-dimensional finite element models. The thickness of the crestal cortical bone and stiffness of the graft were varied in the models to simulate different clinical scenarios, representing variation in the anatomy and graft quality. Axial and lateral loads were considered and the stresses developed in the supporting structures were analyzed. The finite element models showed different stress patterns associated with helical threads. The von Mises stress distribution indicated that stress was maximal around the top of the implant with varying intensities in both loading cases. The stress was highest in the cortical bone, lower in the grafted bone, and lowest in the cancellous bone. When the stiffness of the grafted bone approximated the cortical bone, axial loading resulted in stress reduction in all the native bone layers; however, lateral loading produced stress reduction in only the cancellous bone. When the stiffness of the graft was less than that of the cancellous bone, the graft assumed a lesser proportion of axial loads. Thus, it caused a concomitant stress increase in all the native bones, whereas this phenomenon was observed in only the cancellous bone with lateral loading. The crestal cortical bone, though receiving the highest intensity stresses, affected the overall stress distribution less than the grafted bone. The stress from the lateral load was up to 11 times higher than that of the axial load around the implant. These findings suggest that the type of loading affects the load distribution more than the variations in bone, and native bone is the primary supporting structure.

  17. Biofilm and saliva affect the biomechanical behavior of dental implants.

    PubMed

    Bordin, Dimorvan; Cavalcanti, Indira M G; Jardim Pimentel, Marcele; Fortulan, Carlos A; Sotto-Maior, Bruno S; Del Bel Cury, Altair A; da Silva, Wander José

    2015-04-13

    Friction coefficient (FC) was quantified between titanium-titanium (Ti-Ti) and titanium-zirconia (Ti-Zr), materials commonly used as abutment and implants, in the presence of a multispecies biofilm (Bf) or salivary pellicle (Pel). Furthermore, FC was used as a parameter to evaluate the biomechanical behavior of a single implant-supported restoration. Interface between Ti-Ti and Ti-Zr without Pel or Bf was used as control (Ctrl). FC was recorded using tribometer and analyzed by two-way Anova and Tukey test (p<0.05). Data were transposed to a finite element model of a dental implant-supported restoration. Models were obtained varying abutment material (Ti and Zr) and FCs recorded (Bf, Pel, and Ctrl). Maximum and shear stress were calculated for bone and equivalent von Misses for prosthetic components. Data were analyzed using two-way ANOVA (p<0.05) and percentage of contribution for each condition (material and FC) was calculated. FC significant differences were observed between Ti-Ti and Ti-Zr for Ctrl and Bf groups, with lower values for Ti-Zr (p<0.05). Within each material group, Ti-Ti differed between all treatments (p<0.05) and for Ti-Zr, only Pel showed higher values compared with Ctrl and Bf (p<0.05). FC contributed to 89.83% (p<0.05) of the stress in the screw, decreasing the stress when the FC was lower. FC resulted in an increase of 59.78% of maximum stress in cortical bone (p=0.05). It can be concluded that the shift of the FC due to the presence of Pel or Bf is able to jeopardize the biomechanical behavior of a single implant-supported restoration.

  18. A Biomechanical Comparison of Two Intramedullary Implants for Subtrochanteric Fracture in Two Healing Stages: A Finite Element Analysis

    PubMed Central

    Wu, Xinlei; Yang, Ming; Wu, Lijun; Niu, Wenxin

    2015-01-01

    Background. The biomechanical effect of two implants, namely, proximal femoral nail antirotation for Asia (PFNA-II) and Expert Asian Femoral Nail (A2FN), for treating subtrochanteric fracture during healing stages, is still unclear. Methods. A 3D finite element model of an intact femur was constructed and validated. The fractured and postoperative models were accordingly produced. The postoperative models were loaded with the peak joint forces during gait for the soft and hard callus stages. The effects of stress distribution on the implants, femoral head and callus, and the deformation of the proximal femur were examined. Results. Both implants showed similar biomechanical effect in two healing stages. As the healing duration increased, the von Mises stress of two implants and the tensile stress of the femoral head decreased, whereas the compressive stress of the femoral head increased. However, the PFNA-II operation resulted in higher stress on the implant, lower stress on the proximal femur, and lower compressive stress and higher tensile stress on the callus than A2FN operation. Conclusions. The A2FN implant may provide a biomechanically superior construct for subtrochanteric fracture healing. However, the upper screw of the A2FN implant may be more likely to be loose in the healing process. PMID:27019584

  19. The Comparison of Stress Distribution with Different Implant Numbers and Inclination Angles In All-on-four and Conventional Methods in Maxilla: A Finite Element Analysis

    PubMed Central

    Saleh Saber, Fariba; Ghasemi, Shima; Koodaryan, Rodabeh; Babaloo, Amirreza; Abolfazli, Nader

    2015-01-01

    Background and aims. All-on-four technique involves the use of tilted implants to allow for shorter cantilevers. This finite element analysis aimed at investigating the amount and distribution of stress in maxillary bone surrounding the implants with all-on-four vs. frequently used method with six implants technique using different numbers and inclination angles. Materials and methods. A 3D edentulous maxillary model was created and implants were virtually placed anterior to the maxillary sinus and splinted with a superstructure. In total, five models were designed. In the first to the fourth models, four implants were placed with distal implants inclined 0, 15, 30, and 45 degrees, respectively. In the fifth model, six vertical implants were placed. 100 N loading was placed in the left most distal region of the superstructure. Maximum von Mises stress values were evaluated in cancellous and cortical bone. Results. The maximum stress values recorded in cancellous and cortical bone were 7.15 MPa and 51.69 MPa, respectively (model I). The reduction in stress values in models II to V 6%, 18%, 54%, and 24% in cancellous bone and 12%, 36%,62%, and 62% in cortical bone, respectively. Conclusion. Increasing the inclination in posterior implants resulted in reduction of cantilever length and maximum stress decline in both cancellous and cortical bone. The effect of cantilever length seems to be a dominant factor which can diminish stress even with less number of implants. PMID:26889362

  20. The Comparison of Stress Distribution with Different Implant Numbers and Inclination Angles In All-on-four and Conventional Methods in Maxilla: A Finite Element Analysis.

    PubMed

    Saleh Saber, Fariba; Ghasemi, Shima; Koodaryan, Rodabeh; Babaloo, Amirreza; Abolfazli, Nader

    2015-01-01

    Background and aims. All-on-four technique involves the use of tilted implants to allow for shorter cantilevers. This finite element analysis aimed at investigating the amount and distribution of stress in maxillary bone surrounding the implants with all-on-four vs. frequently used method with six implants technique using different numbers and inclination angles. Materials and methods. A 3D edentulous maxillary model was created and implants were virtually placed anterior to the maxillary sinus and splinted with a superstructure. In total, five models were designed. In the first to the fourth models, four implants were placed with distal implants inclined 0, 15, 30, and 45 degrees, respectively. In the fifth model, six vertical implants were placed. 100 N loading was placed in the left most distal region of the superstructure. Maximum von Mises stress values were evaluated in cancellous and cortical bone. Results. The maximum stress values recorded in cancellous and cortical bone were 7.15 MPa and 51.69 MPa, respectively (model I). The reduction in stress values in models II to V 6%, 18%, 54%, and 24% in cancellous bone and 12%, 36%,62%, and 62% in cortical bone, respectively. Conclusion. Increasing the inclination in posterior implants resulted in reduction of cantilever length and maximum stress decline in both cancellous and cortical bone. The effect of cantilever length seems to be a dominant factor which can diminish stress even with less number of implants.

  1. A Three-Dimensional Finite Element Study on the Biomechanical Simulation of Various Structured Dental Implants and Their Surrounding Bone Tissues

    PubMed Central

    Zhang, Gong; Yuan, Hai; Chen, Xianshuai; Wang, Weijun; Chen, Jianyu; Liang, Jimin; Zhang, Peng

    2016-01-01

    Background/Purpose. This three-dimensional finite element study observed the stress distribution characteristics of 12 types of dental implants and their surrounding bone tissues with various structured abutments, implant threads, and healing methods under different amounts of concentrated loading. Materials and Methods. A three-dimensional geometrical model of a dental implant and its surrounding bone tissue was created; the model simulated a screw applied with a preload of 200 N or a torque of 0.2 N·m and a prosthetic crown applied with a vertical or an inclined force of 100 N. The Von Mises stress was evaluated on the 12 types of dental implants and their surrounding bone tissues. Results. Under the same loading force, the stress influence on the implant threads was not significant; however, the stress influence on the cancellous bone was obvious. The stress applied to the abutment, cortical bone, and cancellous bone by the inclined force applied to the crown was larger than the stress applied by the vertical force to the crown, and the abutment stress of the nonsubmerged healing implant system was higher than that of the submerged healing implant system. Conclusion. A dental implant system characterised by a straight abutment, rectangle tooth, and nonsubmerged healing may provide minimum value for the implant-bone interface. PMID:26904121

  2. Dr. von Braun at the Manufacturing and Engineering Laboratory

    NASA Technical Reports Server (NTRS)

    1967-01-01

    Dr. von Braun, Director of the Marshall Space Flight Center, listens attentively to a briefing on the metal forming techniques by Dr. Mathias Siebel of the Manufacturing and Engineering Laboratory at MSFC on October 17, 1967.

  3. 33. HISTORIC VIEW OF WERNHER VON BRAUN LOOKS THROUGH THE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    33. HISTORIC VIEW OF WERNHER VON BRAUN LOOKS THROUGH THE PERISCOPE FROM THE CONTROL ROOM AT TEST STAND NO. 1, PEENEMUENDE. - Marshall Space Flight Center, Redstone Rocket (Missile) Test Stand, Dodd Road, Huntsville, Madison County, AL

  4. Fletcher and von Braun at Apollo 15 launch

    NASA Technical Reports Server (NTRS)

    1971-01-01

    Recently appointed NASA Administrator Dr. James C. Fletcher, left, and Dr. Wernher von Braun, Deputy Associate Administrator for Planning, monitor Apollo 15 prelaunch activities in Firing Room 1 of the Launch Control Center and the Kennedy Space Center, Florida.

  5. Dr. Wernher Von Braun examines a ruby crystal.

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Dr. Wernher Von Braun (right), director of the Marshall Space Flight Center, and Dr. Eberhard Rees (left), deputy director, technical, examine a ruby crystal used in laser experiments in the Marshall Center's Space Sciences Laboratory.

  6. 7. Historic American Buildings Survey, Charles Von Urban, Photographer June ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. Historic American Buildings Survey, Charles Von Urban, Photographer June 23, 1936, INTERIOR-PARLOR SHOWING FIREPLACE, WINDOWN TRIM, AND CORNICE. - George Fordham House, 329 Cherry Street, New York County, NY

  7. Numerische Berechnung von Wirbelstromproblemen mit der Cell-Methode

    NASA Astrophysics Data System (ADS)

    Frenner, K.; Rucker, W. M.

    2006-09-01

    In dieser Arbeit wird die Cell-Methode auf die quasistatischen Maxwellgleichungen angewendet. Dabei werden für die notwendige Transformation vom Primärgitter auf das duale Gitter reziproke Basisvektoren verwendet. Anhand der Felddiffusion der magnetischen Induktion in einen zylindrischen Leiter werden Ergebnisse der Cell-Methode mit einer analytischen Vergleichsrechnung präsentiert.

  8. Wernher von Braun with German Officers and Others

    NASA Technical Reports Server (NTRS)

    1942-01-01

    General Erich Fellgiebel, head of the German Army Information Service during World War II, congratulates members of the von Braun rocket team from Peenemunde for their October 3, 1942 A4 flight. Pictured front center is General Erich Fellgiebel. Shaking hands are General Walter Dornberger (left) and General Janssen, commanding officer of Peenemuende with Rudolph Hermarn to their right. Picture left to right in the back row are Wernher von Braun, Captain Stoelzel, Luftwaffe, and Dr. Gerhard Reisig.

  9. Gastrointestinal angiodysplasia and bleeding in von Willebrand disease.

    PubMed

    Franchini, M; Mannucci, P M

    2014-09-02

    Von Willebrand disease (VWD), the most common genetic bleeding disorder, is characterised by a quantitative or qualitative defect of von Willebrand factor (VWF). Patients with VWD suffer from mucocutaneous bleeding, of severity usually proportional to the degree of VWF defect. In particular, gastrointestinal bleeding associated with angiodysplasia is often a severe symptom of difficult management. This review focuses on the pathophysiology, diagnosis and treatment of VWD-associated gastrointestinal angiodysplasia and related bleeding.

  10. Management of Type 2B von Willebrand Disease during Pregnancy.

    PubMed

    McLaughlin, David; Kerr, Ron

    2017-01-01

    Type 2B von Willebrand disease is a rare bleeding condition resulting in thrombocytopenia and a reduction in large VWF multimers. It usually has an autosomal dominant pattern of inheritance. We report the management of a patient with type 2B von Willebrand disease, whose diagnosis was confirmed by demonstration of a R1306W mutation, through her first pregnancy. The patient's von Willebrand factor (VWF) antigen and VWF ristocetin cofactor levels rose throughout pregnancy, with an associated drop in the platelet count. The patient was successfully managed through labour to a surgical delivery with VWF concentrate, platelet transfusions and tranexamic acid. The patient delivered a male baby who was found to have inherited type 2B von Willebrand disease and had a significant cephalhaematoma at delivery. The baby was managed with VWF concentrate and platelet transfusions and made a full recovery. There is a lack of evidence to guide the best management of pregnant patients with type 2B von Willebrand disease. We adopted a pragmatic management plan, in keeping with other published case reports. To the best of our knowledge, this is the first case report in which the child was found to have inherited type 2B von Willebrand disease and encountered bleeding problems, making this case unique amongst the published literature.

  11. Long-Term Fatigue and Its Probability of Failure Applied to Dental Implants.

    PubMed

    Prados-Privado, María; Prados-Frutos, Juan Carlos; Gehrke, Sérgio Alexandre; Sánchez Siles, Mariano; Calvo Guirado, José Luis; Bea, José Antonio

    2016-01-01

    It is well known that dental implants have a high success rate but even so, there are a lot of factors that can cause dental implants failure. Fatigue is very sensitive to many variables involved in this phenomenon. This paper takes a close look at fatigue analysis and explains a new method to study fatigue from a probabilistic point of view, based on a cumulative damage model and probabilistic finite elements, with the goal of obtaining the expected life and the probability of failure. Two different dental implants were analysed. The model simulated a load of 178 N applied with an angle of 0°, 15°, and 20° and a force of 489 N with the same angles. Von Mises stress distribution was evaluated and once the methodology proposed here was used, the statistic of the fatigue life and the probability cumulative function were obtained. This function allows us to relate each cycle life with its probability of failure. Cylindrical implant has a worst behaviour under the same loading force compared to the conical implant analysed here. Methodology employed in the present study provides very accuracy results because all possible uncertainties have been taken in mind from the beginning.

  12. A comparative analysis based on different strength criteria for evaluation of risk factor for dental implants.

    PubMed

    Natali, A N; Pavan, P G

    2002-04-01

    A numerical analysis is developed to study the interaction phenomena between endousseus titanium dental implants and surrounding jawbone tissue. The interest is focused on the most appropriate evaluation of the stress state arising in the tissue because of the implant under physiological loading. The problem is considered with regard to linear elastic response of the one and to short time effect. Different configurations of bone-implant system are described, using axial-symmetrical and three-dimensional models, by means of finite and geometric element method. The investigation attains to the stress states induced in bone that lead to a limit condition near the effective failure surface. The parameter commonly adopted in literature, such as the Von Mises stress, represents an excessive simplification of problem formulation, leading to an incorrect evaluation of the real failure risk for the implant, due to the assumption of the isotropic and deviatoric nature of the adopted stress measure. More suitable criterion can be assumed, such as the Tsai-Wu criterion, to take into account the anisotropy that characterises the response of bone, as well as the influence of a hydrostatic stress state. The analysis developed offers a comparison of results by using different criteria, leading to an evaluation of reliability of the procedure to be followed and addressing also to an evaluation of a risk factor for the implant investigated.

  13. Long-Term Fatigue and Its Probability of Failure Applied to Dental Implants

    PubMed Central

    Prados-Frutos, Juan Carlos; Gehrke, Sérgio Alexandre; Calvo Guirado, José Luis; Bea, José Antonio

    2016-01-01

    It is well known that dental implants have a high success rate but even so, there are a lot of factors that can cause dental implants failure. Fatigue is very sensitive to many variables involved in this phenomenon. This paper takes a close look at fatigue analysis and explains a new method to study fatigue from a probabilistic point of view, based on a cumulative damage model and probabilistic finite elements, with the goal of obtaining the expected life and the probability of failure. Two different dental implants were analysed. The model simulated a load of 178 N applied with an angle of 0°, 15°, and 20° and a force of 489 N with the same angles. Von Mises stress distribution was evaluated and once the methodology proposed here was used, the statistic of the fatigue life and the probability cumulative function were obtained. This function allows us to relate each cycle life with its probability of failure. Cylindrical implant has a worst behaviour under the same loading force compared to the conical implant analysed here. Methodology employed in the present study provides very accuracy results because all possible uncertainties have been taken in mind from the beginning. PMID:27517052

  14. BOOK REVIEW: Meilensteine der Astronomie - Von Aristoteles bis Hawking

    NASA Astrophysics Data System (ADS)

    Duerbeck, H. W.; Hamel, J.

    2006-12-01

    neglected, other astronomers? Before the chapter dealing with Aristoteles and other Greek thinkers, the author presents a very good introduction to prehistoric astronomy. Subsequent chapters cover medieval times (Sacrobosco), Copernicus, instruments (Apian), calendars and their makers, telescopes and theological conflicts, women in astronomy and celestial mechanics, "amateur" astronomers (Herschel and Bessel), philosophy and science (Kant and successors). "At the limits of knowledge" is the title of the last, somewhat scanty chapter on 20th century astronomy. The only confusing text is found on p. 43: Die exzentrische Lage der Spharen wurde von Hipparch im 2. Jahrhundert v. Chr. eingefuhrt. Cum grano salis, this is correct; Hipparchos assumed an eccentric orbit for the Sun. Furthermore, die Erde steht im Mittelpunkt des Deferenten, jedoch um den Betrag der Exzentrizitat E vom Mittelpunkt des Exzenters entfernt. A figure showing a deferent circle (and attached epicycle) with center M, and a lower point E called center of world = center of Earth in the caption, tries to illustrate this. The desperate reader does not find the eccenter in the figure, and also does not appreciate why the Earth is in the center of the deferent M when the caption says it is in E. The explanation is that for a planet, having two anomalies, the epicycle does not run on a concentric circle, usually called deferent, but on an eccenter. Thus, in the figure, the circle labelled deferent is the eccenter. In Cellarius' Harmonia Macrocosmica, Table 14, a similar figure explains it all: Eccentricus deferens epicyclum - the eccenter that carries around the epicycle. Since we have switched to Latin, we should mention that on p. 158, we encountered the sentence "in dubia pro res". Perhaps we are permitted to reply "si tacuisses, philosophus mansisses". The reader is cautioned: if this book is used as a road atlas for the history of astronomy, the reader will often find very rough sketches of the progress of

  15. Graphene synthesis by ion implantation

    PubMed Central

    Garaj, Slaven; Hubbard, William; Golovchenko, J. A.

    2010-01-01

    We demonstrate an ion implantation method for large-scale synthesis of high quality graphene films with controllable thickness. Thermally annealing polycrystalline nickel substrates that have been ion implanted with carbon atoms results in the surface growth of graphene films whose average thickness is controlled by implantation dose. The graphene film quality, as probed with Raman and electrical measurements, is comparable to previously reported synthesis methods. The implantation synthesis method can be generalized to a variety of metallic substrates and growth temperatures, since it does not require a decomposition of chemical precursors or a solvation of carbon into the substrate. PMID:21124725

  16. Implant biomaterials: A comprehensive review

    PubMed Central

    Saini, Monika; Singh, Yashpal; Arora, Pooja; Arora, Vipin; Jain, Krati

    2015-01-01

    Appropriate selection of the implant biomaterial is a key factor for long term success of implants. The biologic environment does not accept completely any material so to optimize biologic performance, implants should be selected to reduce the negative biologic response while maintaining adequate function. Every clinician should always gain a thorough knowledge about the different biomaterials used for the dental implants. This article makes an effort to summarize various dental bio-materials which were used in the past and as well as the latest material used now. PMID:25610850

  17. Spiritual aspects of death and dying.

    PubMed Central

    Mermann, A. C.

    1992-01-01

    Dying is an event beyond our comprehension, an experience that can only be imagined. Patients with cancer have a gift denied many others: some time to prepare for the approaching end of life. This time can be used to bring old conflicts to a close, to say goodbye and seek forgiveness from others, to express love and gratitude for the gifts of a life. Physicians can help patients by being aware of the spiritual dimensions to life that many patients have. In major religious traditions, death is accepted as the natural end of the gift of life and as a point of transition to another, yet unknown, existence. For many patients, it is not death that is feared, but abandonment. The physician's awareness of the spiritual needs of patients can make care of the dying more rewarding and fulfilling for all concerned. PMID:1519377

  18. Architecture for on-die interconnect

    SciTech Connect

    Khare, Surhud; More, Ankit; Somasekhar, Dinesh; Dunning, David S.

    2016-03-15

    In an embodiment, an apparatus includes: a plurality of islands configured on a semiconductor die, each of the plurality of islands having a plurality of cores; and a plurality of network switches configured on the semiconductor die and each associated with one of the plurality of islands, where each network switch includes a plurality of output ports, a first set of the output ports are each to couple to the associated network switch of an island via a point-to-point interconnect and a second set of the output ports are each to couple to the associated network switches of a plurality of islands via a point-to-multipoint interconnect. Other embodiments are described and claimed.

  19. Clayton's compromises and the assisted dying debate.

    PubMed

    Parker, Malcolm

    2015-03-01

    Richard Huxtable has recently argued that while assisted dying has been both repeatedly condemned and commended, a compromise resolution is possible. Following critique of other purported solutions, he argues for a new legal offence of "compassionate killing" as a plausible compromise between supporters and opponents of legalised assisted dying, because it offers something of significance to both sides. However, it turns out that "compassionate killing" would leave both sides with insufficient net benefit for the proposal to qualify as a compromise between them. By analogy with another apparently intractable bioethical debate, concerning destructive embryo research, this column rejects Huxtable's solution as another "Clayton's compromise". True compromise is not possible in bioethical debates involving divisions over deeply held values and world views. Resolving such debates inevitably involves the substitution of one dominant world view with another.

  20. Fewer Patients Die During Hospital Inspection Weeks: Study

    MedlinePlus

    ... 164254.html Fewer Patients Die During Hospital Inspection Weeks: Study Slight differences in death rates were possibly ... likely to die if they are treated during weeks that inspectors are checking on the staff, a ...

  1. Historical review of die drool phenomenon during plastics extrusion

    NASA Astrophysics Data System (ADS)

    Musil, Jan; Zatloukal, Martin

    2013-04-01

    Die drool phenomenon is defined as unwanted spontaneous accumulation of extruded polymer melt on open faces of extrusion die during extrusion process. Such accumulated material builds up on the die exit and frequently or continually sticks onto the extruded product and thus damages it. Since die drool appears, extrusion process must be shut down and die exit must be manually cleaned which is time and money consuming. Although die drool is complex phenomenon and its formation mechanism is not fully understood yet, variety of proposed explanations of its formation mechanism and also many ways to its elimination can be found in open literature. Our review presents in historical order breakthrough works in the field of die drool research, shows many ways to suppress it, introduces methods for its quantitative evaluation and composition analysis and summarizes theories of die drool formation mechanism which can be helpful for extrusion experts.

  2. Implantable medical sensor system

    DOEpatents

    Darrow, Christopher B.; Satcher, Jr., Joe H.; Lane, Stephen M.; Lee, Abraham P.; Wang, Amy W.

    2001-01-01

    An implantable chemical sensor system for medical applications is described which permits selective recognition of an analyte using an expandable biocompatible sensor, such as a polymer, that undergoes a dimensional change in the presence of the analyte. The expandable polymer is incorporated into an electronic circuit component that changes its properties (e.g., frequency) when the polymer changes dimension. As the circuit changes its characteristics, an external interrogator transmits a signal transdermally to the transducer, and the concentration of the analyte is determined from the measured changes in the circuit. This invention may be used for minimally invasive monitoring of blood glucose levels in diabetic patients.

  3. Broad beam ion implanter

    DOEpatents

    Leung, K.N.

    1996-10-08

    An ion implantation device for creating a large diameter, homogeneous, ion beam is described, as well as a method for creating same, wherein the device is characterized by extraction of a diverging ion beam and its conversion by ion beam optics to an essentially parallel ion beam. The device comprises a plasma or ion source, an anode and exit aperture, an extraction electrode, a divergence-limiting electrode and an acceleration electrode, as well as the means for connecting a voltage supply to the electrodes. 6 figs.

  4. Broad beam ion implanter

    DOEpatents

    Leung, Ka-Ngo

    1996-01-01

    An ion implantation device for creating a large diameter, homogeneous, ion beam is described, as well as a method for creating same, wherein the device is characterized by extraction of a diverging ion beam and its conversion by ion beam optics to an essentially parallel ion beam. The device comprises a plasma or ion source, an anode and exit aperture, an extraction electrode, a divergence-limiting electrode and an acceleration electrode, as well as the means for connecting a voltage supply to the electrodes.

  5. Non-isothermal analysis of die corner gap formation for materials deformed by multi-pass ECAP

    NASA Astrophysics Data System (ADS)

    Medeiros, N.; Moreira, L. P.

    2014-08-01

    In this paper, the upper-bound solutions proposed by Eivani and Karimi Taheri [Comp. Mater. Sci. 42 (2008) 14] to calculate processing force and evaluate die corner angle Ψ formation in terms of tribology and die configurations during cold single pass equal channels angular pressed metals with constant flow stress were extended to work-hardening metals processed by two passes according to route A by using the Swift model combined to von Mises isotropic plasticity criterion. Also, adiabatic heat equation was coupled to solutions to express the final temperature of the workpiece. For that, thermomechanical properties of a hot-dip galvanized interstitial-free (IF) were considered and its behavior under pressing was evaluated to non-hardening and work-hardening conditions in all performed analyses. By including work-hardening in the models and for the critical friction factor of 0.4, theoretical predictions after single pass showed a decreasing of die corner angle and pressing force predictions and increasing of effective plastic strain and end temperature for all friction conditions and tooling geometries evaluated. In addition, after second pass, these responses showed higher values. Finally, with the proposed upper-bound models it was possible to analyze the dependency of angle Ψ, effective plastic strain, pressing load and sample temperature with the instantaneous workpiece height at the entry surface of deformation zone.

  6. Age at implantation and auditory memory in cochlear implanted children.

    PubMed

    Mikic, B; Miric, D; Nikolic-Mikic, M; Ostojic, S; Asanovic, M

    2014-05-01

    Early cochlear implantation, before the age of 3 years, provides the best outcome regarding listening, speech, cognition an memory due to maximal central nervous system plasticity. Intensive postoperative training improves not only auditory performance and language, but affects auditory memory as well. The aim of this study was to discover if the age at implantation affects auditory memory function in cochlear implanted children. A total of 50 cochlear implanted children aged 4 to 8 years were enrolled in this study: early implanted (1-3y) n = 27 and late implanted (4-6y) n = 23. Two types of memory tests were used: Immediate Verbal Memory Test and Forward and Backward Digit Span Test. Early implanted children performed better on both verbal and numeric tasks of auditory memory. The difference was statistically significant, especially on the complex tasks. Early cochlear implantation, before the age of 3 years, significantly improve auditory memory and contribute to better cognitive and education outcomes.

  7. Hospice Use Following Implantable Cardioverter-Defibrillator Implantation in Older Patients

    PubMed Central

    Reynolds, Matthew R.; Normand, Sharon-Lise; Parzynski, Craig S.; Spertus, John A.; Mor, Vincent; Mitchell, Susan L.

    2016-01-01

    Background— Older recipients of implantable cardioverter-defibrillators (ICDs) are at increased risk for short-term mortality in comparison with younger patients. Although hospice use is common among decedents aged >65, its use among older ICD recipients is unknown. Methods and Results— Medicare patients aged >65 matched to data in the National Cardiovascular Data Registry – ICD Registry from January 1, 2006 to March 31, 2010 were eligible for analysis (N=194 969). The proportion of ICD recipients enrolled in hospice, cumulative incidence of hospice admission, and factors associated with time to hospice enrollment were evaluated. Five years after device implantation, 50.9% of patients were either deceased or in hospice. Among decedents, 36.8% received hospice services. The cumulative incidence of hospice enrollment, accounting for the competing risk of death, was 4.7% (95% confidence interval [CI], 4.6%–4.8%) within 1 year and 21.3% (95% CI, 20.7%–21.8%) at 5 years. Factors most strongly associated with shorter time to hospice enrollment were older age (adjusted hazard ratio, 1.77; 95% CI, 1.73–1.81), class IV heart failure (versus class I; adjusted hazard ratio, 1.79; 95% CI, 1.66–1.94); ejection fraction <20 (adjusted hazard ratio, 1.57; 95% CI, 1.48–1.67), and greater hospice use among decedents in the patients’ health referral region. Conclusions— More than one-third of older patients dying with ICDs receive hospice care. Five years after implantation, half of older ICD recipients are either dead or in hospice. Hospice providers should be prepared for ICD patients, whose clinical trajectories and broader palliative care needs require greater focus. PMID:27016104

  8. [Implant rehabilitation of distal mandibular atrophy using a blade implant].

    PubMed

    Veron, C; Chanavaz, M

    1997-11-01

    After a brief revision of the anatomy of the posterior mandible and its natural resorption pattern, the ramus plate-form implant would be the implant of choice for the rehabilitation of this region. This "site specific" implant is inserted on the top of the crest and superficially impacted within the residual alveolar bone at the distal segment of the horizontal branch and guided to climb parallel to the anterior aspect of the ascending ramus. Its form and specific dimensions are perfectly compatible with the frequently limited quantity of available bone above the nerve canal in patients with advanced atrophy of the posterior mandible. It provides a predictable abutment for the implant-supported or dento-implant-supported prostheses of the posterior mandible.

  9. von Willebrand factor expression in osteosarcoma metastasis.

    PubMed

    Eppert, Kolja; Wunder, Jay S; Aneliunas, Vicky; Kandel, Rita; Andrulis, Irene L

    2005-03-01

    A number of genes are implicated in the initiation and progression of osteosarcoma; however, cytogenetic and comparative genomic hybridization studies indicate the involvement of additional unidentified genes. An examination of gene expression profiles in 22 high-grade osteosarcoma tumor specimens from 15 patients (including paired primary and metastatic samples from five patients) indicated that von Willebrand factor (vWF) mRNA expression may increase during tumor progression. vWF, a large glycoprotein previously considered to be expressed exclusively by endothelial cells and megakaryocytes, is involved in platelet aggregation and adhesion to the subendothelial matrix, processes critical to hematogenous tumor cell metastasis to the lung. Analysis of paired primary and metastatic osteosarcoma tumor samples from 10 patients revealed an increase in vWF gene expression in metastases (P=0.005). Immunohistochemistry showed that, in addition to the endothelial cells, vWF protein was also detected in osteosarcoma cells in vivo in 13 of 29 tumor specimens as well as in SAOS2, an osteosarcoma cell line. The tumor cell staining correlated positively with high vWF expression in the sample (P=0.006). Although vascular endothelial cells contribute to the vWF mRNA detected in the tumor samples, there was neither any correlation between vascular density (VD) and vWF mRNA expression nor between VD and clinical outcome. These findings suggest that vWF expression is deregulated in osteosarcoma tumors, potentially contributing to metastasis.

  10. Unwinding the von Willebrand factor strings puzzle.

    PubMed

    De Ceunynck, Karen; De Meyer, Simon F; Vanhoorelbeke, Karen

    2013-01-10

    von Willebrand factor (VWF) is amongst others synthesized by endothelial cells and stored as ultra-large (UL) VWF multimers in Weibel-Palade bodies. Although UL-VWF is proteolysed by ADAMTS13 (a disintegrin-like and metalloprotease domain with thrombospondin type-1 motif, number 13) on secretion from endothelial cells, in vitro experiments in the absence of ADAMTS13 have demonstrated that a proportion of these UL-VWF multimers remain anchored to the activated endothelium. These multimers unravel, bind platelets, and wave in the direction of the flow. These so-called VWF "strings" have also been visualized in vivo, lining the lumen of activated mesenteric veins of Adamts13(-/-) mice. Various studies have demonstrated the extraordinary length of these VWF strings, the availability of their platelet binding and ADAMTS13 cleavage sites, and the possible nature of their endothelial attachment. VWF strings are also capable of tethering leukocytes and parasite-infected red blood cells. However, the majority of studies have been performed in the absence of ADAMTS13, a condition only experienced in thrombotic thrombocytopenic purpura. A normal functional role of VWF strings in healthy persons or in other disease pathologies remains unclear. In this review, we discuss some of the puzzling characteristics of VWF strings, and we debate whether the properties of VWF strings in the absence of ADAMTS13 might be relevant for understanding (patho)physiologic mechanisms.

  11. Quantum control by von Neumann measurements

    NASA Astrophysics Data System (ADS)

    Pechen, Alexander; Il'in, Nikolai; Shuang, Feng; Rabitz, Herschel

    2006-11-01

    A general scheme is presented for controlling quantum systems using evolution driven by nonselective von Neumann measurements, with or without an additional tailored electromagnetic field. As an example, a two-level quantum system controlled by nonselective quantum measurements is considered. The control goal is to find optimal system observables such that consecutive nonselective measurement of these observables transforms the system from a given initial state into a state which maximizes the expected value of a target operator (the objective). A complete analytical solution is found including explicit expressions for the optimal measured observables and for the maximal objective value given any target operator, any initial system density matrix, and any number of measurements. As an illustration, upper bounds on measurement-induced population transfer between the ground and the excited states for any number of measurements are found. The anti-Zeno effect is recovered in the limit of an infinite number of measurements. In this limit the system becomes completely controllable. The results establish the degree of control attainable by a finite number of measurements.

  12. Exponential Size Distribution of von Willebrand Factor

    PubMed Central

    Lippok, Svenja; Obser, Tobias; Müller, Jochen P.; Stierle, Valentin K.; Benoit, Martin; Budde, Ulrich; Schneppenheim, Reinhard; Rädler, Joachim O.

    2013-01-01

    Von Willebrand Factor (VWF) is a multimeric protein crucial for hemostasis. Under shear flow, it acts as a mechanosensor responding with a size-dependent globule-stretch transition to increasing shear rates. Here, we quantify for the first time, to our knowledge, the size distribution of recombinant VWF and VWF-eGFP using a multilateral approach that involves quantitative gel analysis, fluorescence correlation spectroscopy, and total internal reflection fluorescence microscopy. We find an exponentially decaying size distribution of multimers for recombinant VWF as well as for VWF derived from blood samples in accordance with the notion of a step-growth polymerization process during VWF biosynthesis. The distribution is solely described by the extent of polymerization, which was found to be reduced in the case of the pathologically relevant mutant VWF-IIC. The VWF-specific protease ADAMTS13 systematically shifts the VWF size distribution toward smaller sizes. This dynamic evolution is monitored using fluorescence correlation spectroscopy and compared to a computer simulation of a random cleavage process relating ADAMTS13 concentration to the degree of VWF breakdown. Quantitative assessment of VWF size distribution in terms of an exponential might prove to be useful both as a valuable biophysical characterization and as a possible disease indicator for clinical applications. PMID:24010664

  13. Richard von Volkmann: surgeon and Renaissance man.

    PubMed

    Willy, Christian; Schneider, Peter; Engelhardt, Michael; Hargens, Alan R; Mubarak, Scott J

    2008-02-01

    Richard von Volkmann (1830-1889), one of the most important surgeons of the 19(th) century, is regarded as one of the fathers of orthopaedic surgery. He was a contemporary of Langenbeck, Esmarch, Lister, Billroth, Kocher, and Trendelenburg. He was head of the Department of Surgery at the University of Halle, Germany (1867-1889). His popularity attracted doctors and patients from all over the world. He was the lead physician for the German military during two wars. From this experience, he compared the mortality of civilian and war injuries and investigated the general poor hygienic conditions in civilian hospitals. This led him to introduce the "antiseptic technique" to Germany that was developed by Lister. His powers of observation and creativity led him to findings and achievements that to this day bear his name: Volkmann's contracture and the Hueter-Volkmann law. Additionally, he was a gifted writer; he published not only scientific literature but also books of children's fairy tales and poems under the pen name of Richard Leander, assuring him a permanent place in the world of literature as well as orthopaedics.

  14. A Contextualist Thanatology: A Pragmatic Approach to Death and Dying

    ERIC Educational Resources Information Center

    Reck, Andrew J.

    1977-01-01

    Denying the value of death but accepting its reality, the author points to dying, not death, as the problematic phenomenon with which a pragmatist thanatology must deal. It is suggested that dying contains opportunities for growth--for the dying as well as for their surviving friends and relatives. (Author)

  15. Darwin als Sehhilfe für die Psychologie - Evolutionspsychologie

    NASA Astrophysics Data System (ADS)

    Schwab, Frank

    Im Folgenden geht es um Einäugige, stereoskopisches Sehen, weite und enge Horizonte, Monokel und Sonnenbrillen. Der Beitrag versucht die Metapher des Sehens und der Sehhilfen anzuwenden, um so zu verdeutlichen, welchen Gewinn die herkömmliche Psychologie durch die Verwendung einer Darwin'schen Brille erlangen kann.

  16. A Contingency Framework for Listening to the Dying

    ERIC Educational Resources Information Center

    Vora, Erika; Vora, Ariana

    2008-01-01

    Listening to the dying poses special challenges. This paper proposes a contingency framework for describing and assessing various circumstances when listening to the dying. It identifies current approaches to listening, applies the contingency framework toward effectively listening to the dying, and proposes a new type of listening called…

  17. Die and telescoping punch form convolutions in thin diaphragm

    NASA Technical Reports Server (NTRS)

    1965-01-01

    Die and punch set forms convolutions in thin dished metal diaphragm without stretching the metal too thin at sharp curvatures. The die corresponds to the metal shape to be formed, and the punch consists of elements that progressively slide against one another under the restraint of a compressed-air cushion to mate with the die.

  18. 5 Ways to Cope When a Loved One Dies

    MedlinePlus

    ... Week of Healthy Breakfasts Shyness 5 Ways to Cope When a Loved One Dies KidsHealth > For Teens > 5 Ways to Cope When a Loved One Dies Print A A ... Here are 5 ideas that might help you cope when someone you love has died: Join in ...

  19. 25 CFR 304.2 - Marking and ownership of dies.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 2 2011-04-01 2011-04-01 false Marking and ownership of dies. 304.2 Section 304.2 Indians INDIAN ARTS AND CRAFTS BOARD, DEPARTMENT OF THE INTERIOR NAVAJO, PUEBLO, AND HOPI SILVER, USE OF GOVERNMENT MARK § 304.2 Marking and ownership of dies. All dies used to mark silver will be provided by...

  20. 25 CFR 304.2 - Marking and ownership of dies.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 25 Indians 2 2013-04-01 2013-04-01 false Marking and ownership of dies. 304.2 Section 304.2 Indians INDIAN ARTS AND CRAFTS BOARD, DEPARTMENT OF THE INTERIOR NAVAJO, PUEBLO, AND HOPI SILVER, USE OF GOVERNMENT MARK § 304.2 Marking and ownership of dies. All dies used to mark silver will be provided by...

  1. 25 CFR 304.5 - Dies to identify tribe.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 25 Indians 2 2014-04-01 2014-04-01 false Dies to identify tribe. 304.5 Section 304.5 Indians INDIAN ARTS AND CRAFTS BOARD, DEPARTMENT OF THE INTERIOR NAVAJO, PUEBLO, AND HOPI SILVER, USE OF GOVERNMENT MARK § 304.5 Dies to identify tribe. Dies are marked with name of tribe. A Navajo stamp will...

  2. 25 CFR 304.2 - Marking and ownership of dies.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 25 Indians 2 2012-04-01 2012-04-01 false Marking and ownership of dies. 304.2 Section 304.2 Indians INDIAN ARTS AND CRAFTS BOARD, DEPARTMENT OF THE INTERIOR NAVAJO, PUEBLO, AND HOPI SILVER, USE OF GOVERNMENT MARK § 304.2 Marking and ownership of dies. All dies used to mark silver will be provided by...

  3. 25 CFR 304.2 - Marking and ownership of dies.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 25 Indians 2 2014-04-01 2014-04-01 false Marking and ownership of dies. 304.2 Section 304.2 Indians INDIAN ARTS AND CRAFTS BOARD, DEPARTMENT OF THE INTERIOR NAVAJO, PUEBLO, AND HOPI SILVER, USE OF GOVERNMENT MARK § 304.2 Marking and ownership of dies. All dies used to mark silver will be provided by...

  4. 25 CFR 304.5 - Dies to identify tribe.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 25 Indians 2 2012-04-01 2012-04-01 false Dies to identify tribe. 304.5 Section 304.5 Indians INDIAN ARTS AND CRAFTS BOARD, DEPARTMENT OF THE INTERIOR NAVAJO, PUEBLO, AND HOPI SILVER, USE OF GOVERNMENT MARK § 304.5 Dies to identify tribe. Dies are marked with name of tribe. A Navajo stamp will...

  5. 25 CFR 304.5 - Dies to identify tribe.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 25 Indians 2 2013-04-01 2013-04-01 false Dies to identify tribe. 304.5 Section 304.5 Indians INDIAN ARTS AND CRAFTS BOARD, DEPARTMENT OF THE INTERIOR NAVAJO, PUEBLO, AND HOPI SILVER, USE OF GOVERNMENT MARK § 304.5 Dies to identify tribe. Dies are marked with name of tribe. A Navajo stamp will...

  6. 25 CFR 304.5 - Dies to identify tribe.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 2 2011-04-01 2011-04-01 false Dies to identify tribe. 304.5 Section 304.5 Indians INDIAN ARTS AND CRAFTS BOARD, DEPARTMENT OF THE INTERIOR NAVAJO, PUEBLO, AND HOPI SILVER, USE OF GOVERNMENT MARK § 304.5 Dies to identify tribe. Dies are marked with name of tribe. A Navajo stamp will...

  7. 25 CFR 301.3 - Specifications of dies.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 2 2010-04-01 2010-04-01 false Specifications of dies. 301.3 Section 301.3 Indians INDIAN ARTS AND CRAFTS BOARD, DEPARTMENT OF THE INTERIOR NAVAJO, PUEBLO, AND HOPI SILVER AND TURQUOISE PRODUCTS; STANDARDS § 301.3 Specifications of dies. Dies used are to be entirely hand-made, with no...

  8. 25 CFR 304.5 - Dies to identify tribe.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 2 2010-04-01 2010-04-01 false Dies to identify tribe. 304.5 Section 304.5 Indians INDIAN ARTS AND CRAFTS BOARD, DEPARTMENT OF THE INTERIOR NAVAJO, PUEBLO, AND HOPI SILVER, USE OF GOVERNMENT MARK § 304.5 Dies to identify tribe. Dies are marked with name of tribe. A Navajo stamp will...

  9. 25 CFR 301.4 - Application of dies.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 2 2010-04-01 2010-04-01 false Application of dies. 301.4 Section 301.4 Indians INDIAN ARTS AND CRAFTS BOARD, DEPARTMENT OF THE INTERIOR NAVAJO, PUEBLO, AND HOPI SILVER AND TURQUOISE PRODUCTS; STANDARDS § 301.4 Application of dies. Dies are to be applied to the object with the aid...

  10. 25 CFR 301.4 - Application of dies.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 2 2011-04-01 2011-04-01 false Application of dies. 301.4 Section 301.4 Indians INDIAN ARTS AND CRAFTS BOARD, DEPARTMENT OF THE INTERIOR NAVAJO, PUEBLO, AND HOPI SILVER AND TURQUOISE PRODUCTS; STANDARDS § 301.4 Application of dies. Dies are to be applied to the object with the aid...

  11. 25 CFR 301.4 - Application of dies.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 25 Indians 2 2013-04-01 2013-04-01 false Application of dies. 301.4 Section 301.4 Indians INDIAN ARTS AND CRAFTS BOARD, DEPARTMENT OF THE INTERIOR NAVAJO, PUEBLO, AND HOPI SILVER AND TURQUOISE PRODUCTS; STANDARDS § 301.4 Application of dies. Dies are to be applied to the object with the aid...

  12. 25 CFR 301.3 - Specifications of dies.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 25 Indians 2 2012-04-01 2012-04-01 false Specifications of dies. 301.3 Section 301.3 Indians INDIAN ARTS AND CRAFTS BOARD, DEPARTMENT OF THE INTERIOR NAVAJO, PUEBLO, AND HOPI SILVER AND TURQUOISE PRODUCTS; STANDARDS § 301.3 Specifications of dies. Dies used are to be entirely hand-made, with no...

  13. 25 CFR 301.4 - Application of dies.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 25 Indians 2 2012-04-01 2012-04-01 false Application of dies. 301.4 Section 301.4 Indians INDIAN ARTS AND CRAFTS BOARD, DEPARTMENT OF THE INTERIOR NAVAJO, PUEBLO, AND HOPI SILVER AND TURQUOISE PRODUCTS; STANDARDS § 301.4 Application of dies. Dies are to be applied to the object with the aid...

  14. 25 CFR 301.3 - Specifications of dies.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 2 2011-04-01 2011-04-01 false Specifications of dies. 301.3 Section 301.3 Indians INDIAN ARTS AND CRAFTS BOARD, DEPARTMENT OF THE INTERIOR NAVAJO, PUEBLO, AND HOPI SILVER AND TURQUOISE PRODUCTS; STANDARDS § 301.3 Specifications of dies. Dies used are to be entirely hand-made, with no...

  15. 25 CFR 301.4 - Application of dies.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 25 Indians 2 2014-04-01 2014-04-01 false Application of dies. 301.4 Section 301.4 Indians INDIAN ARTS AND CRAFTS BOARD, DEPARTMENT OF THE INTERIOR NAVAJO, PUEBLO, AND HOPI SILVER AND TURQUOISE PRODUCTS; STANDARDS § 301.4 Application of dies. Dies are to be applied to the object with the aid...

  16. 25 CFR 301.3 - Specifications of dies.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 25 Indians 2 2013-04-01 2013-04-01 false Specifications of dies. 301.3 Section 301.3 Indians INDIAN ARTS AND CRAFTS BOARD, DEPARTMENT OF THE INTERIOR NAVAJO, PUEBLO, AND HOPI SILVER AND TURQUOISE PRODUCTS; STANDARDS § 301.3 Specifications of dies. Dies used are to be entirely hand-made, with no...

  17. 25 CFR 301.3 - Specifications of dies.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 25 Indians 2 2014-04-01 2014-04-01 false Specifications of dies. 301.3 Section 301.3 Indians INDIAN ARTS AND CRAFTS BOARD, DEPARTMENT OF THE INTERIOR NAVAJO, PUEBLO, AND HOPI SILVER AND TURQUOISE PRODUCTS; STANDARDS § 301.3 Specifications of dies. Dies used are to be entirely hand-made, with no...

  18. [Determination of von Willebrand factor multimers in Mexican population].

    PubMed

    Hernández-Zamora, Edgar; Zavala-Hernández, Cesar; Viveros-Sandoval, Martha Eva; Ochoa-Rico, Angeles; Martínez-Murillo, Carlos; Reyes-Maldonado, Elba

    2014-01-01

    Antecedentes: la enfermedad de von Willebrand es un padecimiento hereditario en el que la estructura, función y concentración del factor de von Willebrand están alteradas y, en consecuencia, también la interacción plaqueta-factor de von Willebrand-endotelio. En México no hay registros epidemiológicos de la enfermedad, sólo se han efectuado algunos estudios aislados desde el punto de vista clínico y hematológico. Material y métodos: estudio retrospectivo efectuado en 155 mexicanos mestizos, 75 de ellos con diagnóstico presuntivo de enfermedad de von Willebrand, 15 con sospecha de hemofilia A y 65 donadores sanos (testigos). Se realizaron pruebas: básicas de coagulación, especiales y de clasificación: análisis de la composición multimérica. Resultados: 15 pacientes se diagnosticaron con hemofilia A; de los 75 sujetos con sospecha de enfermedad de von Willebrand se diagnosticaron 50 de la manera siguiente: tipo 1 (62%), tipo 2 (22%) [subtipos: 2A (14%), 2B (2%) y 2N (6%)] y tipo 3 (16%). Conclusión: el análisis de los multímeros del factor de von Willebrand es un método que cumple con las características adecuadas para el diagnóstico de la enfermedad de von Willebrand, por lo que es necesario implementar esta metodología para su estudio y mejorar su diagnóstico específico.

  19. A novel ELISA-based diagnosis of acquired von Willebrand disease with increased VWF proteolysis.

    PubMed

    Rauch, Antoine; Caron, Claudine; Vincent, Flavien; Jeanpierre, Emmanuelle; Ternisien, Catherine; Boisseau, Pierre; Zawadzki, Christophe; Fressinaud, Edith; Borel-Derlon, Annie; Hermoire, Sylvie; Paris, Camille; Lavenu-Bombled, Cécile; Veyradier, Agnès; Ung, Alexandre; Vincentelli, André; van Belle, Eric; Lenting, Peter J; Goudemand, Jenny; Susen, Sophie

    2016-05-02

    Von Willebrand disease-type 2A (VWD-2A) and acquired von Willebrand syndrome (AVWS) due to aortic stenosis (AS) or left ventricular assist device (LVAD) are associated with an increased proteolysis of von Willebrand factor (VWF). Analysis of VWF multimeric profile is the most sensitive way to assess such increased VWF-proteolysis. However, several technical aspects hamper a large diffusion among routine diagnosis laboratories. This makes early diagnosis and early appropriate care of increased proteolysis challenging. In this context of unmet medical need, we developed a new ELISA aiming a quick, easy and reliable assessment of VWF-proteolysis. This ELISA was assessed successively in a LVAD-model, healthy subjects (n=39), acquired TTP-patients (n=4), VWD-patients (including VWD-2A(IIA), n=22; VWD-2B, n=26; VWD-2A(IIE), n=21; and VWD-1C, n=8) and in AVWS-patients (AS, n=9; LVAD, n=9; and MGUS, n=8). A standard of VWF-proteolysis was specifically developed. Extent of VWF-proteolysis was expressed as relative percentage and as VWF proteolysis/VWF:Ag ratio. A speed-dependent increase in VWF-proteolysis was assessed in the LVAD model whereas no proteolysis was observed in TTP-patients. In VWD-patients, VWF-proteolysis was significantly increased in VWD-2A(IIA) and VWD-2B and significantly decreased in VWD-2A(IIE) versus controls (p< 0.0001). In AVWS-patients, VWF-proteolysis was significantly increased in AS- and LVAD-patients compared to controls (p< 0.0001) and not detectable in MGUS-patients. A significant increase in VWF-proteolysis was detected as soon as three hours after LVAD implantation (p< 0.01). In conclusion, we describe a new ELISA allowing a rapid and accurate diagnosis of VWF-proteolysis validated in three different clinical situations. This assay represents a helpful alternative to electrophoresis-based assay in the diagnosis and management of AVWS with increased VWF-proteolysis.

  20. Implant Maintenance: A Clinical Update

    PubMed Central

    Gulati, Minkle; Govila, Vivek; Anand, Vishal; Anand, Bhargavi

    2014-01-01

    Introduction. The differences in the supporting structure of the implant make them more susceptible to inflammation and bone loss when plaque accumulates as compared to the teeth. Therefore, a comprehensive maintenance protocol should be followed to ensure the longevity of the implant. Material and Method. A research to provide scientific evidence supporting the feasibility of various implant care methods was carried out using various online resources to retrieve relevant studies published since 1985. Results. The electronic search yielded 708 titles, out of which a total of 42 articles were considered appropriate and finally included for the preparation of this review article. Discussion. A typical maintenance visit for patients with dental implants should last 1 hour and should be scheduled every 3 months to evaluate any changes in their oral and general history. It is essential to have a proper instrument selection to prevent damage to the implant surface and trauma to the peri-implant tissues. Conclusion. As the number of patients opting for dental implants is increasing, it becomes increasingly essential to know the differences between natural teeth and implant care and accept the challenges of maintaining these restorations. PMID:27437506

  1. Differentiating suicide decedents who died using firearms from those who died using other methods.

    PubMed

    Anestis, Michael D; Khazem, Lauren R; Anestis, Joye C

    2017-02-22

    Studies have documented a link between gun ownership and suicide, but little is known about characteristics of those most likely to use a gun in a suicide attempt rather than alternative methods. We examined which factors differentiate suicide decedents who died using a gun from those who died by other methods. We further examined whether such findings are consistent within the subcomponent of our larger sample comprised entirely of gun owning suicide decedents. Data reflect 267 suicide decedents, with data provided by individuals who identified as having lost someone to suicide (loss survivors). Within the full sample, a higher proportion of gun-owning and male suicide decedents died by firearm. Further, individuals who had previously discussed suicide or engaged in one or more non-lethal suicide attempts were less likely to die by suicide using a gun. Within the subsample of gun owning suicide decedents, a greater proportion of decedents who stored guns at home and in unsecure locations died from self-inflected gunshot wounds. These findings add clarity to the relationship between firearm ownership and death by suicide at the individual level. Furthermore, these findings are consistent with the notion that means safety implementation may represent a vital suicide prevention tool.

  2. Recombinant von Willebrand factor: a first-of-its-kind product for von Willebrand disease.

    PubMed

    Singal, M; Kouides, P A

    2016-12-01

    von Willebrand disease (VWD) is caused by quantitative or qualitative defects in von Willebrand factor (VWF). The mainstay of therapy is desmopressin, which is, however, not useful in certain forms of VWD notwithstanding adverse events. For these patients, plasma-derived factor VIII (pdFVIII)/VWF concentrates have been available for close to three decades but have a theoretical risk of disease transmission, hypersensitivity/allergic reactions, inhibitors and thrombosis. A recombinant VWF (vonicog alfa, Vonvendi™; manufactured by Baxalta, now part of Shire) was approved by the U.S. Food and Drug Administration (FDA) in December 2015. This review will survey the literature based on a MEDLINE review on the safety, efficacy and pharmacokinetics of Vonvendi. It will also summarize the ongoing studies on Vonvendi available in the public domain. Vonvendi may have an important role in the management of VWD. However, more studies are needed, especially in special populations such as surgical patients, patients with major gastrointestinal bleeding from arteriovenous malformations and pregnant women and children, who are most likely to benefit from it.

  3. Diagnostic Value of Measuring Platelet Von Willebrand Factor in Von Willebrand Disease

    PubMed Central

    Casonato, Alessandra; Cattini, Maria Grazia; Daidone, Viviana; Pontara, Elena; Bertomoro, Antonella; Prandoni, Paolo

    2016-01-01

    Von Willebrand disease (VWD) may be caused by an impaired von Willebrand factor (VWF) synthesis, its increased clearance or abnormal function, or combinations of these factors. It may be difficult to recognize the different contributions of these anomalies. Here we demonstrate that VWD diagnostics gains from measuring platelet VWF, which can reveal a defective VWF synthesis. Measuring platelet VWF revealed that: severe type 1 VWD always coincided with significantly lower platelet and plasma VWF levels, whereas mild forms revealed low plasma VWF levels associated with low or normal platelet VWF levels, and the latter were associated with a slightly shorter VWF survival; type Vicenza (the archetype VWD caused by a reduced VWF survival) featured normal platelet VWF levels despite significantly reduced plasma VWF levels; type 2B patients could have either normal platelet VWF levels associated with abnormal multimer patterns, or reduced platelet VWF levels associated with normal multimer patterns; type 2A patients could have reduced or normal platelet VWF levels, the former associated mainly with type 2A-I, the latter with type 2A-II; plasma and platelet VWF levels were normal in type 2N, except when the defect was associated with a quantitative VWF mutation. Our findings show that measuring platelet VWF helps to characterize VWD, especially the ambiguous phenotypes, shedding light on the mechanisms underlying the disorder. PMID:27532107

  4. Regenerative Surgical Treatment of Peri-implantitis

    ClinicalTrials.gov

    2016-08-31

    Failure of Dental Implant Due to Infection; Infection; Inflammation; Peri-implantitis; Bacterial Infections; Bleeding of Subgingival Space; Molecular Sequence Variation; Periodontal Diseases; Mouth Diseases

  5. Progestin implants for female contraception.

    PubMed

    Croxatt, Horacio B

    2002-01-01

    Four different implants, in the form of capsules or covered rods, that release one of the synthetic progestins levonorgestrel, etonogestrel, Nestorone, or Elcometrine and nomegestrol acetate were reviewed. Biocompatible polymers or copolymers of polydimethyl/polymethylvinyl-siloxanes or ethylvinylacetate are used to hold the steroid crystals and to control the rate of release. Once inserted under the skin, these implants release the corresponding steroid continuously over prolonged periods, a process that can be readily interrupted by implant removal. During long-term use of the implant, the released steroid circulates in blood at a fairly stable level. The physical characteristics of the implants, including drug contents and rate of release, serum levels of the progestin during use, and the duration of their effective life are described. Total steroid loads vary in the range of 50 mg to 216 mg; average release rates are in the range of 30-100 ug/day, and effective lives from 6 months to 7 years.

  6. Bimodal fitting or bilateral implantation?

    PubMed

    Ching, Teresa Y C; Massie, Robyn; Van Wanrooy, Emma; Rushbrooke, Emma; Psarros, Colleen

    2009-01-01

    This paper summarises findings from studies that evaluated the benefits of bimodal fitting (combining a hearing aid and a cochlear implant in opposite ears) or bilateral cochlear implantation, relative to unilateral implantation, for children (Ching et al., 2007). On average, the size of binaural speech intelligibility advantages due to redundancy and head shadow was similar for the two bilateral conditions. An added advantage of bimodal fitting was that the low-frequency cues provided by acoustic hearing complemented the high-frequency cues conveyed by electric hearing in perception of voice and music. Some children with bilateral cochlear implants were able to use spatial separation between speech and noise to improve speech perception in noise. This is possibly a combined effect of the directional microphones in their implant systems and their ability to use spatial cues. The evidence to date supports the provision of hearing in two ears as the standard of care.

  7. Cochlear implantation following cerebellar surgery.

    PubMed

    Saeed, Shahad; Mawman, Deborah; Green, Kevin

    2011-08-01

    Cochlear implantation in patients with known central nervous system conditions can result in wide-ranging outcomes. The aim of this study is to report two cases of cochlear implantation outcomes in patients with acquired cerebellar ataxia following cerebellar surgery. The first is a female implanted with the Nucleus 24 implant in September 2000 and the second is a male implanted with a MED-EL Sonata Flexsoft electro-acoustic stimulation in July 2009. Programming these patients resulted in significant non-auditory stimulation which resulted in less than optimum map fittings. The patients did not gain any open set speech perception benefit although both of them gained an awareness of sound with the device. However, patient 2 elected to become a non-user because of the limited benefit.

  8. Energy Saving Melting and Revert Reduction Technology (E-SMARRT): Development of Surface Engineered Coating Systems for Aluminum Pressure Die Casting Dies: Towards a 'Smart' Die Coating

    SciTech Connect

    Dr. John J. Moore; Dr. Jianliang Lin,

    2012-07-31

    The main objective of this research program was to design and develop an optimal coating system that extends die life by minimizing premature die failure. In high-pressure aluminum die-casting, the die, core pins and inserts must withstand severe processing conditions. Many of the dies and tools in the industry are being coated to improve wear-resistance and decrease down-time for maintenance. However, thermal fatigue in metal itself can still be a major problem, especially since it often leads to catastrophic failure (i.e. die breakage) as opposed to a wear-based failure (parts begin to go out of tolerance). Tooling costs remain the largest portion of production costs for many of these parts, so the ability prevent catastrophic failures would be transformative for the manufacturing industry.The technology offers energy savings through reduced energy use in the die casting process from several factors, including increased life of the tools and dies, reuse of the dies and die components, reduction/elimination of lubricants, and reduced machine down time, and reduction of Al solder sticking on the die. The use of the optimized die coating system will also reduce environmental wastes and scrap parts. Current (2012) annual energy saving estimates, based on initial dissemination to the casting industry in 2010 and market penetration of 80% by 2020, is 3.1 trillion BTU's/year. The average annual estimate of CO2 reduction per year through 2020 is 0.63 Million Metric Tons of Carbon Equivalent (MM TCE).

  9. Accurate Die Design for Automotive Panel Stamping Considering the Compensation Related with Die Deflection and Blank Thinning

    NASA Astrophysics Data System (ADS)

    Chen, Jun; Xu, Dongkai; Xia, Guodong; Li, Xifeng; Chen, Jieshi; Zhang, Jian; Yan, Wei; Li, Yue

    2011-08-01

    In order to improve assembly accuracy, automotive body panels have to be fabricated with higher dimensional and surface quality requirements, therefore the die faces should be designed more accurately to consider more relevant factors. In the presented study, we proposed algorithms to realize the following functions: through forming process simulation, the thinning distribution on the deformed blank was extracted as first kind of compensation; through die structural CAE analysis which automatically mapped the boundary contact forces onto the die surfaces from process simulation results, the die deflection was calculated as second kind of compensation. These two quantitative contributions were added together to compensate the die face. The proposed methodologies were programmed and integrated with LS-Dyna and HyperWorks, and also integrated with Autoform and CATIA linear CAE functionalities separately. In addition, a software toolkit to calculate the contacting ratio was also developed to evaluate the effectiveness of die face compensation. The second toolkit developed was verified by an automotive structural part forming die design, through die compensation and geometric optimization, the predicted contact ratio between the die face and formed blank was improved a lot, and the first toolkit was testified by a fender drawing die design. It shows that the die face compensation can be realized and integrated seamlessly between CAD model, process simulation model and die structural CAE model with the help of data I/O tools developed by the authors.

  10. Hydrogen Implants for Layer Exfoliation

    NASA Astrophysics Data System (ADS)

    Cherekdjian, S.; Couillard, J. G.; Wilcox, C.

    2011-01-01

    Researchers at Corning Incorporated have developed a process whereby single crystal silicon thin films are transferred onto a flat panel display glass substrate using hydrogen ion implantation. The energy of the implant controls the effective exfoliation thickness, agreeing well with SRIM calculations, while the hydrogen ion dose controls the size of the platelets formed. The ion dose was found to influence the final void defect count in exfoliated films. Finally, the ion beam and ion implant end-station cooling characteristics were investigated. These parameters control the effective implant heat load generated during ion beam processing. The temperature at which exfoliation occurs during an exfoliation heat cycle was found to be inversely proportional to the hydrogen ion dose when the temperature during ion implantation is <100 °C. The most sensitive exfoliation temperature to ion dose dependence was observed for cooler implants, i.e. <35 °C. Data indicates that at the minimum exfoliation dose the exfoliation temperature is reduced significantly by increasing the implant heat generated during ion beam processing. Higher hydrogen doses than the minimum required for exfoliation exhibit only a small exfoliation temperature variation with ion dose. By optimizing the implant heat load generated during ion beam processing it is observed that the efficiency of the exfoliation process is also enhanced. Implant temperatures of 150 to 160 °C were found to further reduce the minimum implant dose required for exfoliation by an additional 5%, as verified by calorimetric measurements. These results enable us to further conclude that hydrogen out-diffusion is not significant in this process.

  11. Locally Compact Quantum Groups. A von Neumann Algebra Approach

    NASA Astrophysics Data System (ADS)

    Van Daele, Alfons

    2014-08-01

    In this paper, we give an alternative approach to the theory of locally compact quantum groups, as developed by Kustermans and Vaes. We start with a von Neumann algebra and a comultiplication on this von Neumann algebra. We assume that there exist faithful left and right Haar weights. Then we develop the theory within this von Neumann algebra setting. In [Math. Scand. 92 (2003), 68-92] locally compact quantum groups are also studied in the von Neumann algebraic context. This approach is independent of the original C^*-algebraic approach in the sense that the earlier results are not used. However, this paper is not really independent because for many proofs, the reader is referred to the original paper where the C^*-version is developed. In this paper, we give a completely self-contained approach. Moreover, at various points, we do things differently. We have a different treatment of the antipode. It is similar to the original treatment in [Ann. Sci. & #201;cole Norm. Sup. (4) 33 (2000), 837-934]. But together with the fact that we work in the von Neumann algebra framework, it allows us to use an idea from [Rev. Roumaine Math. Pures Appl. 21 (1976), 1411-1449] to obtain the uniqueness of the Haar weights in an early stage. We take advantage of this fact when deriving the other main results in the theory. We also give a slightly different approach to duality. Finally, we collect, in a systematic way, several important formulas. In an appendix, we indicate very briefly how the C^*-approach and the von Neumann algebra approach eventually yield the same objects. The passage from the von Neumann algebra setting to the C^*-algebra setting is more or less standard. For the other direction, we use a new method. It is based on the observation that the Haar weights on the C^*-algebra extend to weights on the double dual with central support and that all these supports are the same. Of course, we get the von Neumann algebra by cutting down the double dual with this unique

  12. Method and apparatus for die forming metal sheets and extrusions

    NASA Astrophysics Data System (ADS)

    Darter, John L.

    1986-06-01

    The invention comprises an apparatus for die forming metal sheets and extrusions which utilizes die blocks of low melting temperature metallic material. The die blocks are formed in an adjustable mold which comprises a mold box, a pivotable dam within the mold box and blocking means for locking the pivotable dam member in a desired angular position. Once a desired die block angle is ascertained for a particular joggle, the pivotable member of the mold box is adjusted to produce the desired angle in the die casting made in the mold box.

  13. Sheet metal stamping die design for warm forming

    DOEpatents

    Ghosh, Amit K.

    2003-04-22

    In metal stamping dies, by taking advantage of improved material flow by selectively warming the die, flat sections of the die can contribute to the flow of material throughout the workpiece. Local surface heating can be accomplished by placing a heating block in the die. Distribution of heating at the flat lower train central regions outside of the bend region allows a softer flow at a lower stress to enable material flow into the thinner, higher strain areas at the bend/s. The heating block is inserted into the die and is powered by a power supply.

  14. Tribological properties of nitrogen implanted and boron implanted steels

    SciTech Connect

    Kern, K.T.; Walter, K.C.; Griffin, A.J. Jr.; Kung, H.; Lu, Y.; Nastasi, M.; Tesmer, J.R.; Fayeulle, S.

    1996-06-01

    Samples of a steel with high chrome content was implanted separately with 75 keV nitrogen ions and with 75 keV boron ions. Implanted doses of each ion species were 2-, 4-, and 8 {times} 10{sup 17}/cm{sup 2}. Retained doses were measured using resonant non-Rutherford Backscattering Spectrometry. Tribological properties were determined using a pin-on-disk test with a 6-mm diameter ruby pin with a velocity of 0.94 m/min. Testing was done at 10% humidity with a load of 377 g. Wear rate and coefficient of friction were determined from these tests. While reduction in the wear rate for nitrogen implanted materials was observed, greater reduction (more than an order of magnitude) was observed for boron implanted materials. In addition, reduction in the coefficient of friction for high-dose boron implanted materials was observed. Nano-indentation revealed a hardened layer near the surface of the material. Results from grazing incidence x-ray diffraction suggest the formation of Fe{sub 2}N and Fe{sub 3}N in the nitrogen implanted materials and Fe{sub 3}B in the boron implanted materials. Results from transmission electron microscopy will be presented.

  15. Three-Dimensional Finite Element Analysis of Anterior Single Implant-Supported Prostheses with Different Bone Anchorages

    PubMed Central

    Verri, Fellippo Ramos; Santiago Júnior, Joel Ferreira; Almeida, Daniel Augusto de Faria; Verri, Ana Caroline Gonçales; de Souza Batista, Victor Eduardo; Lemos, Cleidiel Aparecido Araujo; Noritomi, Pedro Yoshito; Pellizzer, Eduardo Piza

    2015-01-01

    The aim of this study was to evaluate the stress distribution of monocortical and bicortical implant placement of external hexagon connection in the anterior region of the maxilla by 3D finite element analysis (FEA). 3D models were simulated to represent a bone block of anterior region of the maxilla containing an implant (4.0 × 10.0 mm) and an implant-supported cemented metalloceramic crown of the central incisor. Different techniques were tested (monocortical, bicortical, and bicortical associated with nasal floor elevation). FEA was performed in FEMAP/NeiNastran software using loads of 178 N at 0°, 30°, and 60° in relation to implant long axis. The von Mises, maximum principal stress, and displacement maps were plotted for evaluation. Similar stress patterns were observed for all models. Oblique loads increased the stress concentration on fixation screws and in the cervical area of the implants and bone around them. Bicortical technique showed less movement tendency in the implant and its components. Cortical bone of apical region showed increase of stress concentration for bicortical techniques. Within the limitations of this study, oblique loading increased the stress concentrations for all techniques. Moreover, bicortical techniques showed the best biomechanical behavior compared with monocortical technique in the anterior maxillary area. PMID:26351654

  16. Stress distribution in cylindrical and conical implants under rotational micromovement with different boundary conditions and bone properties: 3-D FEA.

    PubMed

    Dos Santos, Mateus Bertolini Fernandes; Meloto, Gabriel de Oliveira; Bacchi, Ataís; Correr-Sobrinho, Lourenço

    2017-03-28

    Factors related to micromovements at bone-implant interface have been studied because they are considered adverse to osseointegration. Simplifications are commonly observed in these FEA evaluations. The aim of this study was to clarify the influence of FEA parameters (boundary conditions and bone properties) on the stress distribution in peri-implant bone tissue when micromovements are simulated in implants with different geometries. Three-dimensional models of an anterior section of the jaw with cylindrical or conical titanium implants (4.1 mm in width and 11 mm in length) were created. Micromovement (50, 150, or 250 μm) was applied to the implant. The FEA parameters studied were linear vs. non-linear analyses, isotropic vs. orthogonal anisotropic bone, friction coefficient (0.3) vs. frictionless bone-implant contact. Data from von Mises, shear, maximum, and minimum principal stresses in the peri-implant bone tissue were compared. Linear analyses presented a relevant increase of the stress values, regardless of the bone properties. Frictionless contact reduced the stress values in non-linear analysis. Isotropic bone presented lower stress than orthogonal anisotropic. Conical implants behave better, in regard to compressive stresses (minimum principal), than cylindrical ones, except for nonlinear analyses when micromovement of 150 and 250 μm were simulated. The stress values raised as the micromovement amplitude increased. Non-linear analysis, presence of frictional contact and orthogonal anisotropic bone, evaluated through maximum and minimum principal stress should be used as FEA parameters for implant-micromovement studies.

  17. Biosynthesis of von Willebrand protein by human megakaryocytes.

    PubMed

    Sporn, L A; Chavin, S I; Marder, V J; Wagner, D D

    1985-09-01

    Immunofluorescence staining of buffy coat smears from a patient with chronic myelogenous leukemia in accelerated phase showed that approximately 13% of all nucleated cells contained von Willebrand protein and, therefore, appeared to be of megakaryocytic origin. This was confirmed by positive staining with antisera against platelet factor 4 and platelet glycoproteins. Short-term cultures of the buffy coat, which lacked endothelial cells, were metabolically labeled with [35S]methionine, and von Willebrand protein was immunopurified from cell lysates and culture medium. Cultures from this patient synthesized and secreted von Willebrand protein, in contrast with cultures from other patients with leukemia, who lacked circulating megakaryocytes, and from normal volunteers. The subunit composition of the megakaryocytic von Willebrand protein was very similar to that of human umbilical vein endothelial cells. The size of the processed subunit (220 kD) and of the cellular (260 kD) and secreted (275 kD) precursors from the two cell types were indistinguishable by gel electrophoresis. Furthermore, the ratio of precursor to processed subunit and the pattern of cellular and secreted nonreduced multimers were very similar. It appears, therefore, that the processing steps in biosynthesis of von Willebrand protein used by the megakaryocytes are very similar to those of umbilical vein endothelial cells.

  18. Biographical sketch: Georg Hermann von Meyer (1815-1892).

    PubMed

    Skedros, John G; Brand, Richard A

    2011-11-01

    This biographical sketch on Georg Hermann von Meyer highlights the interactions in the 1860s that von Meyer, a famous anatomist, had with Karl Culmann, a famous structural engineer and mathematician. The published papers from this interaction caught the attention of Julius Wolff and stimulated his development of the trajectorial hypothesis of bone adaptation--now called "Wolff's Law." The corresponding translations are provided: (1) von Meyer's 1867 paper that highlights the regularity of arched trabecular patterns in various human bones, and his discussions with Culmann about their possible mechanical relevance; and (2) Wolff's 1869 paper that first mentions the correspondence of stress trajectories in a solid, crane-like structure to the arched trabecular patterns in the proximal human femur. This biographical sketch on Georg Hermann von Meyer corresponds to the historic texts, The Classic: The Architecture of the Trabecular bone (by von Meyer), and The Classic: On the Significance of the Architecture of the Spongy Substance for the Question of Bone Growth. A preliminary publication (by Wolff) available at DOIs 10.1007/s11999-011-2041-5 , 10.1007/s11999-011-2042-4 .

  19. Double valve Implantation

    PubMed Central

    Stassano, Paolo; Mannacio, Vito; Musumeci, Antonino; Golino, Alessandro; Maida, Piero; Ferrigno, Vincenzo; Buonocore, Gaetano; Spampinato, Nicola

    1991-01-01

    From January 1976 through December 1987, 194 patients with a mean age of 43.3 ± 13.7 years (range, 11 to 74 years) underwent double (mitral and aortic) replacement of native valves with 8 types of bioprostheses: Carpentier-Edwards, 127 valves; Hancock, 76 valves; Liotta-Bioimplant, 57 valves; Ionescu-Shiley, 53 valves; Vascor, 27 valves; Carpentier-Edwards Pericardial, 22 valves; Angell-Shiley, 20 valves; and Implamedic, 6 valves. Concomitant cardiac procedures were performed in 25 patients (12.8%). There were 18 operative deaths (9.27%). Our retrospective analysis was restricted to 352 bioprostheses implanted in the 176 patients who survived surgery and were considered at risk for valve tissue failure. The overall cumulative duration of follow-up was 1,174.1 patient-years (range, 1 to 13 years). The durations of follow-up for specific valves were: Carpentier-Edwards, 920.2 valve-years; Hancock, 383.8 valve-years; Liotta-Bioimplant, 310.2 valve-years; Ionescu-Shiley, 357.7 valve-years; Vascor, 131.2 valve-years; Carpentier-Edwards Pericardial, 52.0 valve-years; Angell-Shiley, 167.0 valve-years; and Implamedic, 31.0 valve-years. Thirty patients had thromboembolic accidents, for a linearized incidence of 2.5% per patient-year. At 13 years, the actuarial freedom from thromboembolic accidents was 85.8% ± 10.7%. Nine patients had endocarditis, for a linearized incidence of 0.7% per patient-year. At 13 years, the actuarial freedom from endocarditis was 92.0% ± 1.5%. Twenty-four patients had valve tissue failure, for a cumulative linearized incidence of 1.87% per valve-year. The cumulative actuarial probability of freedom from valve tissue failure was 78.6% ± 3.7% at 10 years and 51.2% ± 10.7% at 13 years. The 24 patients with valve tissue failure all underwent reoperation: 20 of these had double valve replacement, 3 had aortic valve replacement alone, and 1 had mitral valve replacement alone. The mean interval between initial valve implantation and reoperation was

  20. SURGICAL IMPLANTATION OF COELOMIC RADIOTRANSMITTERS AND POSTOPERATIVE SURVIVAL OF CHINESE GIANT SALAMANDERS (ANDRIAS DAVIDIANUS) FOLLOWING REINTRODUCTION.

    PubMed

    Marcec, Ruth; Kouba, Andrew; Zhang, Lu; Zhang, Hongxing; Wang, Qijun; Zhao, Hu; Jiang, Wei; Willard, Scott

    2016-03-01

    Worldwide, there are only a handful of reintroduction programs for threatened salamander species, and very few have conducted postrelease studies to examine survival, habitat selection, and dispersal. Limitations in postrelease monitoring are primarily due to size constraints of amphibians and to dimensions of the radiotransmitters available for implantation. However, due to the large size of the critically endangered Chinese giant salamander (Andrias davidianus), these animals make optimal candidates for surgical implantation of radiotransmitters prior to reintroduction or translocation. The objective of this study was to develop an anesthetic protocol using tricane methanesulfonate (MS-222) and test a surgical procedure for coelomic implantation of radiotransmitters for this species. A total of 32 Chinese giant salamanders from two age groups (Group A: 4.7 yr old, n = 16; Group B: 2.7 yr old, n = 16) were implanted with 4-g radiotransmitters designed for underwater monitoring of fish. Group A was held 16 wk before release while Group B was held 6 wk before release, and the salamanders' survival and postoperative complications recorded for the first month postrelease. Group A animals took longer to reach a surgical plane of anesthesia than did Group B animals, and this was directly correlated to mass of the animals. Postsurgery, one animal from Group B died of dehiscence before release while 83.9% animals survived after the first month in the wild. All of the animals that died postrelease were from Group B; three animals experienced dehiscence of the suture site and died while another two animals expired from trauma and fungal infection, respectively. Improvements for future studies include use of alternative suture material for closure after implantation and additional healing time of the incision.

  1. Euthanasia, assisted dying and the right to die in Ghana: a socio-legal analysis.

    PubMed

    Owusu-Dapaa, Ernest

    2013-12-01

    There is unanimity among states to protect the continuation of life of the individual as a safeguard against their collective extinction. The right to life is accordingly guaranteed but its antithesis, the right to die is the subject of an unending debate. The controversy over the right to die is deepened by rapid advances in medicine, creating the capability for prolongation of life beyond the span which one's natural strength can endure. Ghana's supreme law explicitly guarantees the right to life but remains ambiguous on right to die, particularly euthanasia and assisted dying. Thus, some of the other rights, such as the right to dignity and not to be tortured, can creatively be exploited to justify some instances of euthanasia. Ghana's criminal code largely proscribes euthanasia. Notwithstanding, proscription of euthanasia and assisted dying by the law, in Ghana's empirical work undertaken in some of the communities in Ghana, suggests that euthanasia is quietly practisedin health facilities and private homes, especially in the rural areas. Contrary to the popular reasons assigned in the literature of the Western world, with respect to the practice or quest for legalization of euthanasia as being a necessity for providing relief from pain or hopeless quality of life, empirical data from social and anthropological studies conducted in Ghana reveal that poverty is the motivation for informal euthanasia practice in Ghana rather than genuine desire on part of patients to die or their relatives to see to their accelerated death. Apart from poverty, traditional cultural values of African societies consider non-natural death as a taboo and ignominy to the victim and his family. Thus, any move by the government to legalize euthanasia will need to be informed by widely held consultations and a possible referendum; otherwise the law may be just a mere transplant of Western models of legislation on euthanasia without reflecting the ethos of the African people.

  2. Dying cancer patients talk about euthanasia.

    PubMed

    Eliott, Jaklin A; Olver, Ian N

    2008-08-01

    Within developed nations, there is increasing public debate about and apparent endorsement of the appropriateness of euthanasia as an autonomous choice to die in the face of intolerable suffering. Surveys report socio-demographic differences in rates of acceptance of euthanasia, but there is little in-depth analysis of how euthanasia is understood and positioned within the social and moral lives of individuals, particularly those who might be considered suitable candidates-for example, terminally-ill cancer patients. During discussions with 28 such patients in Australia regarding medical decisions at the end of life, euthanasia was raised by 13 patients, with the others specifically asked about it. Twenty-four patients spoke positively of euthanasia, 19 of these voicing some concerns. None identified euthanasia as a currently favoured option. Four were completely against it. Endorsement for euthanasia was in the context of a hypothetical future or for a hypothetical other person, or temporally associated with acute pain. Arguments supporting euthanasia framed the issue as a matter of freedom of choice, as preserving dignity in death, and as curbing intolerable pain and suffering, both of the patient and of those around them. A common analogy featured was that of euthanising a dog. These arguments were typically presented as self-evident justification for euthanasia, construed as an appropriate choice to die, with opposers positioned as morally inferior or ignorant. The difficulties of ensuring 'choice' and the moral connotations of 'choosing to die,' however, worked to problematise the appropriateness of euthanising specific individuals. We recommend further empirical investigation of the moral and social meanings associated with euthanasia.

  3. Implementing California's Law on Assisted Dying.

    PubMed

    Mishra, Ruchika

    2017-03-01

    On October 5, 2015, Governor Jerry Brown approved bill ABX2 15, the End of Life Option Act, making California the fifth state in the country to allow physician-assisted dying. The law was modeled after Oregon's 1997 Death with Dignity Act. When the legislative special session ended on March 10, 2016, California health care providers had only ninety days to respond to the state mandate before the law would take effect, on June 9, 2016. Experience with the law so far suggests several challenges with implementation.

  4. Do imaginary companions die? An exploratory study.

    PubMed

    Kastenbaum, Robert; Fox, Lynn

    Adults in this exploratory study usually recalled that their childhood imaginary companions faded away or were dismissed as other options for social interaction became more appealing. However, eight participants reported that their IC had died. Analysis of these deaths offers a glimpse of the child's talent for transitional thought processes that navigate between the emerging constraints of logic and the continuing appeal of fantasy. It is suggested that young children are testing the limits and possibilities of what it means to be "real" at the same time they are trying to puzzle out "alive" and "dead."

  5. Die Schokoladen-Diät

    NASA Astrophysics Data System (ADS)

    Ehrhardt, Matthias

    Schlankheitskuren sind einerseits ein soziales Phänomen, aber auch ein großer Zweig der Nahrungsmittelindustrie. Die Industrie bietet dabei verschiedene Produkte an, wie Diätlebensmittel, Nahrungsergänzungsmittel, Sportkleidung und -ausrüstung, Übungsvideos und -bücher, usw. Allerdings ist es bekanntermaßen sehr schwer, das einmal erreichte Wunschgewicht auch langfristig zu halten. Häufig tritt dabei der so genannte Jojo-Effekt auf, so dass man schließlich nach der Diät mehr wiegt als vorher.

  6. Die swell as an objective in the design of polymer extrusion dies

    NASA Astrophysics Data System (ADS)

    Siegbert, Roland; Behr, Marek; Elgeti, Stefanie

    2016-10-01

    This paper focuses on developing a suitable objective function for the inverse form of profile extrusion die design. First, the problem is motivated by introducing the extrusion die design process. After describing how Computer Aided Engineering enhances the traditional design process, a set of applicable objective functions is introduced. The main criteria for identifying the most suitable are computational applicability, robustness and smoothness of the functional. After discussing the results of several simulations, an objective function is proposed for the implementation in an existing optimization framework utilizing parameter-based optimization.

  7. DIE Deflection Modeling: Empirical Validation and Tech Transfer

    SciTech Connect

    R. Allen Miller

    2003-05-28

    This report summarizes computer modeling work that was designed to help understand how the die casting die and machine contribute to parting plane separation during operation. Techniques developed in earlier research (8) were applied to complete a large computational experiment that systematically explored the relationship between the stiffness of the machine platens and key dimensional and structural variables (platen area covered, die thickness, platen thickness, thickness of insert and the location of the die with respect to the platen) describing the die/machine system. The results consistently show that there are many significant interactions among the variables and it is the interactions, more than the individual variables themselves, which determine the performance of the machine/die system. That said, the results consistently show that it is the stiffness of the machine platens that has the largest single impact on die separation.

  8. Thrombospondin-1 in von Willebrand factor function.

    PubMed

    Bonnefoy, Arnaud; Hoylaerts, Marc F

    2008-10-01

    Thrombospondin-1 (TSP1), expressed in many cells and tissues is abundantly present in platelet alpha-granules, from where it is released upon platelet activation. Murine Tsp1(-/-) platelet studies have revealed that TSP1 is redundant for platelet aggregation, but that it reinforces platelet aggregate stabilization, especially in a shear field. von Willebrand factor (VWF), synthesized by megakaryocytes and endothelial cells is stored both in platelet alpha-granules and in endothelial Weibel-Palade bodies as ultralarge multimers. When released from endothelial cells, these multimers are temporarily retained on the endothelium, to be cleaved by the plasma protease ADAMTS13 into smaller and hemostatically less reactive multimers, released in plasma. This protease shows partial sequence identity with the type 1 (TSR1) and type 2 (TSR2) repeats of TSP1 and contains 1 TSR1 and 6 TSR2 repeats. TSP1, locally released by platelets, competes with ADAMTS13 during VWF proteolysis and controls the degree of VWF multimer processing. In addition, TSP1 and VWF both interact with the platelet GPIb/V/IX membrane complex, primarily in flow. These interactions control the recruitment of platelets to (sub) endothelial VWF and TSP1, exposed to the circulation, as a consequence of vascular inflammation and endothelial injury. TSP1-VWF interactions do not strictly enhance platelet recruitment and secreted TSP1 even weakly competes with the dynamic platelet rolling and adhesion onto VWF. Hence, TSP1 and VWF show partially related hemostatic functions, the most important one being the TSP1 role in the ADAMTS13 operated VWF multimer processing, in pro-inflammatory and thrombogenic conditions.

  9. Edelgase als Tracer für Wechselwirkungen von Krusten- und Mantelfluiden mit diamantführenden Gesteinen des östlichen Baltischen Schildes

    NASA Astrophysics Data System (ADS)

    Wiersberg, Thomas

    2001-11-01

    In der vorliegenden Arbeit werden anhand der Edelgaszusammensetzung von Kimberliten und Lamproiten sowie ihrer gesteinsbildenden Minerale die Wechselwirkungen dieser Gesteine mit Fluiden diskutiert. Die untersuchten Proben stammen vom östlichen Baltischen Schild, vom Kola-Kraton (Poria Guba und Kandalaksha) und vom karelischen Kraton (Kostamuksha). Edelgasanalysen nach thermischer oder mechanischer Gasextraktion von 23 Gesamtgesteinsproben und 15 Mineralseparaten ergeben folgendes Bild: Helium- und Neon-Isotopendaten der Fluideinschlüsse von Lamproiten aus Kostamuksha lassen auf den Einfluss einer fluiden Phase krustaler Herkunft schliessen. Diese Wechselwirkungen fanden wahrscheinlich schon während des Magmenaufstiegs statt, denn spätere Einflüsse krustaler Fluide auf die Lamproite und ihr Nebengestein (Quarzit) sind gering, wie anhand der C/36Ar-Zusammensetzung gezeigt wird. Auch sind die mit verschiedenen Datierungsmethoden (Rb-Sr, Sm-Nd, K-Ar) an Mineralseparaten und teilweise an Gesamtgestein ermittelten Alter konsistent und machen eine metamorphe Überprägung unwahrscheinlich. Aufgrund der Verteilung der primordialen Edelgasisotope zwischen Fluideinschlüssen und Gesteinsmatrix ist ein langsamer Magmenaufstieg anzunehmen, was die Möglichkeit der Kontamination mit einem krustalen Fluid während des Magmenaufstiegs erhöht. Die Gasextraktion aus Mineralseparaten erfolgte thermisch, wodurch eine Freisetzung der Gase ausschließlich aus Fluideinschlüssen nicht möglich ist. Hierbei zeigen Amphibol und Klinopyroxen, separiert aus Kostamuksha-Lamproiten, in ihrer Neon-Isotopenzusammensetzung im Vergleich zur krustalen Zusammensetzung (Kennedy et al., 1990) ein leicht erhöhtes Verhältnis von 20Ne/22Ne, was ein Hinweis auf Mantel-Neon sein könnte. Kalifeldspäte, Quarz und Karbonate enthalten dagegen nur Neon krustaler Zusammensetzung. Phlogopite haben sehr kleine Verhältnisse von 20Ne/22Ne und 21Ne/22Ne, zurückzuführen auf in-situ-Produktion von 22Ne

  10. Management of fluocinolone implant dissociation during implant exchange.

    PubMed

    Yeh, Steven; Cebulla, Colleen M; Witherspoon, S Robert; Emerson, Geoffrey G; Emerson, M Vaughn; Suhler, Eric B; Albini, Thomas A; Flaxel, Christina J

    2009-09-01

    Three patients with chronic, noninfectious uveitis requiring immunosuppressive therapy underwent fluocinolone acetonide (FA) implant exchange complicated by dissociation of the medication reservoir from its anchoring strut. In 2 patients, the medication reservoir descended into the vitreous cavity and required pars plana vitrectomy with intraocular foreign body removal techniques for its retrieval. The use of viscoelastic or perfluorocarbon to elevate the device was helpful in the safe removal of the FA implant device. Surgeons performing FA implant exchange should be aware of this potential complication and anticipate the possible need for vitreoretinal instrumentation and personnel. Patients undergoing FA explantation or exchange should be counseled regarding this potential complication prior to surgery.

  11. Percutaneous Transcatheter One-Step Mechanical Aortic Disc Valve Prosthesis Implantation: A Preliminary Feasibility Study in Swine

    SciTech Connect

    Sochman, Jan Peregrin, Jan H.; Rocek, Miloslav; Timmermans, Hans A.; Pavcnik, Dusan; Roesch, Josef

    2006-02-15

    Purpose. To evaluate the feasibility of one-step implantation of a new type of stent-based mechanical aortic disc valve prosthesis (MADVP) above and across the native aortic valve and its short-term function in swine with both functional and dysfunctional native valves. Methods. The MADVP consisted of a folding disc valve made of silicone elastomer attached to either a nitinol Z-stent (Z model) or a nitinol cross-braided stent (SX model). Implantation of 10 MADVPs (6 Z and 4 SX models) was attempted in 10 swine: 4 (2 Z and 2 SX models) with a functional native valve and 6 (4 Z and 2 SX models) with aortic regurgitation induced either by intentional valve injury or by MADVP placement across the native valve. MADVP function was observed for up to 3 hr after implantation. Results. MADVP implantation was successful in 9 swine. One animal died of induced massive regurgitation prior to implantation. Four MADVPs implanted above functioning native valves exhibited good function. In 5 swine with regurgitation, MADVP implantation corrected the induced native valve dysfunction and the device's continuous good function was observed in 4 animals. One MADVP (SX model) placed across native valve gradually migrated into the left ventricle. Conclusion. The tested MADVP can be implanted above and across the native valve in a one-step procedure and can replace the function of the regurgitating native valve. Further technical development and testing are warranted, preferably with a manufactured MADVP.

  12. Implantable, multifunctional, bioresorbable optics

    PubMed Central

    Tao, Hu; Kainerstorfer, Jana M.; Siebert, Sean M.; Pritchard, Eleanor M.; Sassaroli, Angelo; Panilaitis, Bruce J. B.; Brenckle, Mark A.; Amsden, Jason J.; Levitt, Jonathan; Fantini, Sergio; Kaplan, David L.; Omenetto, Fiorenzo G.

    2012-01-01

    Advances in personalized medicine are symbiotic with the development of novel technologies for biomedical devices. We present an approach that combines enhanced imaging of malignancies, therapeutics, and feedback about therapeutics in a single implantable, biocompatible, and resorbable device. This confluence of form and function is accomplished by capitalizing on the unique properties of silk proteins as a mechanically robust, biocompatible, optically clear biomaterial matrix that can house, stabilize, and retain the function of therapeutic components. By developing a form of high-quality microstructured optical elements, improved imaging of malignancies and of treatment monitoring can be achieved. The results demonstrate a unique family of devices for in vitro and in vivo use that provide functional biomaterials with built-in optical signal and contrast enhancement, demonstrated here with simultaneous drug delivery and feedback about drug delivery with no adverse biological effects, all while slowly degrading to regenerate native tissue. PMID:23150544

  13. Implant-supported Mandibular Overdentures in Very Old Adults

    PubMed Central

    Müller, F.; Duvernay, E.; Loup, A.; Vazquez, L.; Herrmann, F.R.; Schimmel, M.

    2013-01-01

    The purpose of this study was (1) to investigate denture satisfaction following the conversion of existing mandibular complete dentures to implant overdentures (IOD) in very old edentulous patients who depend on help for activities of daily living and (2) to evaluate secondary end points, such as functional, structural, nutritional, and patient-centered aspects. For this randomized clinical trial, 2 interforaminal short implants were placed in the intervention group (n = 16, 85.0 ± 6.19 yrs) to retain mandibular IODs; the control group (n = 18, 84.1 ± 5.55 yrs) received conventional relines. During the first year, no implant was lost; however, 2 patients died. IODs proved more stable, and participants in the intervention group demonstrated significantly higher denture satisfaction as well as an increased oral health–related quality of life compared to the control group. Maximum voluntary bite force improved significantly with IODs, yet the chewing efficiency was not different between groups. Masseter muscle thickness increased with IODs, mainly on the preferred chewing side. Body mass index decreased in both groups, but the decline tended to be smaller in the intervention group; blood markers and the Mini Nutritional Assessment did not confirm this tendency. These results indicate that edentulous patients who depend on help for activities of daily living may benefit from IODs even late in life (ClinicalTrial.gov NCT01928004). PMID:24158342

  14. Committee Opinion No.580: von Willebrand disease in women.

    PubMed

    2013-12-01

    Von Willebrand disease, the most common inherited bleeding disorder among American women, is a common cause of heavy menstrual bleeding and other bleeding problems in women and adolescent girls. Von Willebrand disease and other inherited and acquired disorders of coagulation and hemostasis should be considered in the differential diagnosis of all patients being evaluated for heavy menstrual bleeding, regardless of age. There are many treatment options available for patients with von Willebrand disease and heavy menstrual bleeding, including hormonal and nonhormonal therapies. A multidisciplinary approach to management, which involves obstetrician-gynecologists and hematologists, results in optimal treatment outcomes. Many resources exist for patients and health care providers through the National Heart, Lung, and Blood Institute; National Hemophilia Foundation; and the American Society of Hematology.

  15. Patient-Specific Orthopaedic Implants.

    PubMed

    Haglin, Jack M; Eltorai, Adam E M; Gil, Joseph A; Marcaccio, Stephen E; Botero-Hincapie, Juliana; Daniels, Alan H

    2016-11-01

    Patient-specific orthopaedic implants are emerging as a clinically promising treatment option for a growing number of conditions to better match an individual's anatomy. Patient-specific implant (PSI) technology aims to reduce overall procedural costs, minimize surgical time, and maximize patient outcomes by achieving better biomechanical implant fit. With this commercially-available technology, computed tomography or magnetic resonance images can be used in conjunction with specialized computer programs to create preoperative patient-specific surgical plans and to develop custom cutting guides from 3-D reconstructed images of patient anatomy. Surgeons can then place these temporary guides or "jigs" during the procedure, allowing them to better recreate the exact resections of the computer-generated surgical plan. Over the past decade, patient-specific implants have seen increased use in orthopaedics and they have been widely indicated in total knee arthroplasty, total hip arthroplasty, and corrective osteotomies. Patient-specific implants have also been explored for use in total shoulder arthroplasty and spinal surgery. Despite their increasing popularity, significant support for PSI use in orthopaedics has been lacking in the literature and it is currently uncertain whether the theoretical biomechanical advantages of patient-specific orthopaedic implants carry true advantages in surgical outcomes when compared to standard procedures. The purpose of this review was to assess the current status of patient-specific orthopaedic implants, to explore their future direction, and to summarize any comparative published studies that measure definitive surgical characteristics of patient-specific orthopaedic implant use such as patient outcomes, biomechanical implant alignment, surgical cost, patient blood loss, or patient recovery.

  16. Microsystems Technology for Retinal Implants

    NASA Astrophysics Data System (ADS)

    Weiland, James

    2005-03-01

    The retinal prosthesis is targeted to treat age-related macular degeneration, retinitis pigmentosa, and other outer retinal degenerations. Simulations of artificial vision have predicted that 600-1000 individual pixels will be needed if a retinal prosthesis is to restore function such as reading large print and face recognition. An implantable device with this many electrode contacts will require microsystems technology as part of its design. An implantable retinal prosthesis will consist of several subsystems including an electrode array and hermetic packaging. Microsystems and microtechnology approaches are being investigated as possible solutions for these design problems. Flexible polydimethylsiloxane (PDMS) substrate electrode arrays and silicon micromachined electrode arrays are under development. Inactive PDMS electrodes have been implanted in 3 dogs to assess mechanical biocompatibility. 3 dogs were followed for 6 months. The implanted was securely fastened to the retina with a single retinal tack. No post-operative complications were evident. The array remained within 100 microns of the retinal surface. Histological evaluation showed a well preserved retina underneath the electrode array. A silicon device with electrodes suspended on micromachined springs has been implanted in 4 dogs (2 acute implants, 2 chronic implants). The device, though large, could be inserted into the eye and positioned on the retina. Histological analysis of the retina from the spring electrode implants showed that spring mounted posts penetrated the retina, thus the device will be redesigned to reduce the strength of the springs. These initial implants will provide information for the designers to make the next generation silicon device. We conclude that microsystems technology has the potential to make possible a retinal prosthesis with 1000 individual contacts in close proximity to the retina.

  17. Die-target for dynamic powder consolidation

    DOEpatents

    Flinn, J.E.; Korth, G.E.

    1985-06-27

    A die/target is disclosed for consolidation of a powder, especially an atomized rapidly solidified metal powder, to produce monoliths by the dynamic action of a shock wave, especially a shock wave produced by the detonation of an explosive charge. The die/target comprises a rectangular metal block having a square primary surface with four rectangular mold cavities formed therein to receive the powder. The cavities are located away from the geometrical center of the primary surface and are distributed around such center while also being located away from the geometrical diagonals of the primary surface to reduce the action of reflected waves so as to avoid tensile cracking of the monoliths. The primary surface is covered by a powder retention plate which is engaged by a flyer plate to transmit the shock wave to the primary surface and the powder. Spawl plates are adhesively mounted on other surfaces of the block to act as momentum traps so as to reduce reflected waves in the block. 4 figs.

  18. Die-target for dynamic powder consolidation

    DOEpatents

    Flinn, John E.; Korth, Gary E.

    1986-01-01

    A die/target is disclosed for consolidation of a powder, especially an atomized rapidly solidified metal powder, to produce monoliths by the dynamic action of a shock wave, especially a shock wave produced by the detonation of an explosive charge. The die/target comprises a rectangular metal block having a square primary surface with four rectangular mold cavities formed therein to receive the powder. The cavities are located away from the geometrical center of the primary surface and are distributed around such center while also being located away from the geometrical diagonals of the primary surface to reduce the action of reflected waves so as to avoid tensile cracking of the monoliths. The primary surface is covered by a powder retention plate which is engaged by a flyer plate to transmit the shock wave to the primary surface and the powder. Spawl plates are adhesively mounted on other surfaces of the block to act as momentum traps so as to reduce reflected waves in the block.

  19. The dying child and surviving family members.

    PubMed

    Shrier, D K

    1980-12-01

    This overview of death and dying focuses on the dying child and surviving family members. Children's concepts of death at different developmental stages are reviewed. These range from an inability to distinguish death from other forms of separation prior to age 3, through partial concepts of death until, by age 10 to 15 years, children are able to conceptualize death as universal, inevitable and final. The importance of adults assisting in the child's growing comprehension of death is stressed. The stages of grief and mourning, as outlined by Kubler-Ross, are reviewed from the perspective of the child and family: denial, anger, bargaining, depression and acceptance. Recognition is given to the variations in coping styles among different family members. The special circumstances related to the death of an infant and the impact of the death of a child on the surviving siblings are discussed. Specific helpful interventions to assist families in coping with mourning are described. The death of a child remains one of the most painful and difficult events for a family and its physician to accept.

  20. Dying or living?: The double bind.

    PubMed

    Longhofer, J

    1980-06-01

    Describing the behaviors of terminally ill patients, their families and those charged with their care has received considerable attention during the past decade. This study of comprehensive cancer treatment and research facility indicates that the prevailing theory is limited to explanation at the intra-psychic level. In her work with hundreds of terminal cases, Dr. Elizabeth Kubler-Ross found that patients typically progress through five stages: 1) denial, 2) anger, 3) bargaining, 4) depression, and 5) acceptance. She concludes that the majority of her patients die in a stage of acceptance--a state of equanimity. Recently, scholars have claimed that this five stage scheme has limited applicability and may in fact contribute to the formalization of a dying person's behavior. This preliminary report proposes that the stage theory, if it has any descriptive validity, becomes meaningful only when used to describe behaviors occurring among patients, families, and medical practitioners. A plausible explanation of these behaviors is accomplished by examination of communication patterns containing the structure of paradox or double bind. Patients are forced to perceive realities about their physical conditions not as they appear to them, but as they are defined by those in their environment. This paper explores these communication patterns in relation to the structure of social relationships and the specific contents of messages being transmitted and received.

  1. [The debate about the right to die].

    PubMed

    Beca, Juan Pablo; Ortiz, Armando; Solar, Sebastián

    2005-05-01

    The Right to Die is a debatable issue and some basic notions need to be clarified to discuss it. Death needs to be recognized as part of human life. The goal of medicine is to avoid pain and alleviate suffering, to prevent premature death and when this is not possible, to let it occur peacefully. The concept of euthanasia is unclear, which increases the confusion on end-of-life topics. The term euthanasia should be used only when referring to medical acts performed to produce the patient's death, with the intention of terminating his/her suffering. It is what is usually called "active" euthanasia, which can be voluntary or involuntary. It is essential to understand the difference between producing and allowing death. This will permit timely decisions about limiting or withdrawing treatments, that can be disproportionate or that are only prolonging suffering. Limiting treatments does not mean to abandon the patient but rather to redefine his needs, such as pain treatment, prevention of complications, and relief of suffering. The ethic rationale for these decisions is the respect to the dignity of human life, and the estimation of proportionality or futility of each treatment. The physician's duty with the patient at the end of his life is to assist him in dying according to his values and to minimize his distress.

  2. Dying, mourning, and spirituality: a psychological perspective.

    PubMed

    Marrone, R

    1999-09-01

    Based in an unfortunate tradition that stretches back in time to Watson's behaviorism and Freud's psychoanalysis, psychology has tended to reject and to pathologize matters of the spirit. In the past 30 years, however, with the advent of what has been termed the cognitive revolution, psychology has greatly expanded the scope of its subject matter. Psychologists and thanatologists have begun to unravel the cognitive underpinnings of our assumptive world and the transformation of those underpinnings in times of crisis and stress. This article examines the cognitive basis of the spiritual experience and the use of cognitive assimilation, accommodation strategies during the process of mourning the death of a loved one, as well as during the process of living our own dying. Of special importance to mental health professionals and clergy, new research on dying, mourning, and spirituality suggests that the specific ways in which people rediscover meaning--such as belief in traditional religious doctrine, the afterlife, reincarnation, philanthropy, or a spiritual order to the universe--may be less important than the process itself. In other words, in the midst of dealing with profound loss in our lives, the ability to reascribe meaning to a changed world through spiritual transformation, religious conversion, or existential change may be more significant than the specific content by which that need is filled.

  3. Does matching relation exist between the length and the tilting angle of terminal implants in the all-on-four protocol? stress distributions by 3D finite element analysis

    PubMed Central

    Li, Xiaomei; Cao, Zhizhong; Qiu, Xiaoqian; Tang, Zhen; Gong, Lulu

    2015-01-01

    PURPOSE To explore whether there is matching relation between the length and the tilting angle of terminal implants in the All-on-Four protocol by studying the effects of different implant configurations on stress distributions of implant, bone, and framework. MATERIALS AND METHODS Four implants were employed to support a full-arch fixed prosthesis and five three-dimensional finite element models were established with CT images, based on the length (S and L) and distal tilt angle (0°, 30° and 45°) of terminal implants for an edentulous mandible, which named: Tilt0-S, Tilt30-S, Tilt30-L, Tilt45-S and Tilt45-L. An oblique 240 N was loaded at second molar. The von Mises Stresses were analyzed. The implants were consecutively named #1 to #4 from the loading point. RESULTS 1) Tilt0-S had the greatest stress on the implants, with the other groups exhibiting variable reductions; the four implants of Tilt45-L demonstrated the greatest reduction in stress. 2) Tilt0-S had the greatest stress at bone around #1 implant neck, and Tilt45-L exhibited the least stress, which was a 36.3% reduction compared to Tilt0-S. 3) The greatest stress in the framework was found on the cantilevers distal to #1 implant. Tilt45-S exhibited the least stress. CONCLUSION Matching different length and tilting angle of the terminal implants led to variable stress reductions on implants, bone and the superstructure. By optimizing implant configuration, the reduction of stress on implants and surrounding bone could be maximized. Under the present condition, Tilt45-L was the preferred configuration. Further clinical testings are required. PMID:26140176

  4. Improving lithography intra wafer CD for C045 implant layers using STI thickness feed forward?

    NASA Astrophysics Data System (ADS)

    Massin, Jean; Orlando, Bastien; Gatefait, Maxime; Chapon, Jean-Damien; Le-Gratiet, Bertrand; Minghetti, Blandine; Goirand, Pierre-Jérôme

    2008-03-01

    In this paper we performed an analysis of various data collection preformed on C045 production lots in order to assess the influence of STI oxide layers on the CD uniformity of implant photolithography layers. Our final purpose is to show whether the DOSE MAPPER TM software option for interfiled dose correction available on ASML scanners combined with a run-to-run feed-forward regulation loop could improve global CD uniformity on C045 implants layers. After a brief presentation of the C045 implants context the results of the analysis are presented : swing curves, process windows analysis, and intra-die CD measurements are presented. The conclusion of the analysis is that it is not possible, in the current C045 industrial environment, to use a robust and general method of interfield dose correction in order to achieve a better global CD uniformity.

  5. Tag retention, growth, and survival of red swamp crayfish marked with a visible implant tag

    USGS Publications Warehouse

    Isely, J.J.; Stockett, P.E.

    2001-01-01

    Eighty juvenile (means: 42.4 mm total length, 1.6 g) red swamp crayfish Procambarus clarkii were implanted with sequentially numbered visible implant tags and held in the laboratory. Tags were injected transversely into the musculature just beneath the exoskeleton of the third abdominal segment from the cephalothorax; tags were visible upon inspection. An additional 20 crayfish were left untagged and served as controls. After 150 d, tag retention was 80% and all tags were readable. No tagged crayfish died during the study, and no differences in total length or weight were detected between tagged and control crayfish. All individuals molted at least three times during the 150-d study, and some individuals molted up to six times, suggesting that most tags would be permanently retained. The readability in the field without specialized equipment makes the visible implant tag ideal for studies of crayfish ecology, management, and culture.

  6. Male chest enhancement: pectoral implants.

    PubMed

    Benito-Ruiz, J; Raigosa, J M; Manzano-Surroca, M; Salvador, L

    2008-01-01

    The authors present their experience with the pectoral muscle implant for male chest enhancement in 21 patients. The markings and technique are thoroughly described. The implants used were manufactured and custom made. The candidates for implants comprised three groups: group 1 (18 patients seeking chest enhancement), group 2 (1 patient with muscular atrophy), and group 3 (2 patients with muscular injuries). Because of the satisfying results obtained, including significant enhancement of the chest contour and no major complications, this technique is used for an increasing number of male cosmetic surgeries.

  7. [Considerations for optimizing joint implants].

    PubMed

    Tensi, H M; Orloff, S; Gese, H; Hooputra, H

    1994-09-01

    Despite the increasing use of orthopaedic implants, there is still a lack of adequate testing procedures and legal guidelines. Examples of the consequences of this neglect are given. Modern techniques for the calculation of stresses (finite element method [FEM]) and the prediction of life cycle duration are presented. Such methods, applied in the development and manufacturing phases of standard and special implants, may ensure an adequate prosthetic life cycle, with particular emphasis being placed on the biomedical optimization of the implant/bone interface and surrounding bone.

  8. Stress analysis in platform-switching implants: a 3-dimensional finite element study.

    PubMed

    Pellizzer, Eduardo Piza; Verri, Fellippo Ramos; Falcón-Antenucci, Rosse Mary; Júnior, Joel Ferreira Santiago; de Carvalho, Paulo Sérgio Perri; de Moraes, Sandra Lúcia Dantas; Noritomi, Pedro Yoshito

    2012-10-01

    The aim of this study was to evaluate the influence of the platform-switching technique on stress distribution in implant, abutment, and peri-implant tissues, through a 3-dimensional finite element study. Three 3-dimensional mandibular models were fabricated using the SolidWorks 2006 and InVesalius software. Each model was composed of a bone block with one implant 10 mm long and of different diameters (3.75 and 5.00 mm). The UCLA abutments also ranged in diameter from 5.00 mm to 4.1 mm. After obtaining the geometries, the models were transferred to the software FEMAP 10.0 for pre- and postprocessing of finite elements to generate the mesh, loading, and boundary conditions. A total load of 200 N was applied in axial (0°), oblique (45°), and lateral (90°) directions. The models were solved by the software NeiNastran 9.0 and transferred to the software FEMAP 10.0 to obtain the results that were visualized through von Mises and maximum principal stress maps. Model A (implants with 3.75 mm/abutment with 4.1 mm) exhibited the highest area of stress concentration with all loadings (axial, oblique, and lateral) for the implant and the abutment. All models presented the stress areas at the abutment level and at the implant/abutment interface. Models B (implant with 5.0 mm/abutment with 5.0 mm) and C (implant with 5.0 mm/abutment with 4.1 mm) presented minor areas of stress concentration and similar distribution pattern. For the cortical bone, low stress concentration was observed in the peri-implant region for models B and C in comparison to model A. The trabecular bone exhibited low stress that was well distributed in models B and C. Model A presented the highest stress concentration. Model B exhibited better stress distribution. There was no significant difference between the large-diameter implants (models B and C).

  9. Die casting die deflections: Prediction and attenuation. Final report, July 1, 1995--September 30, 1997

    SciTech Connect

    Miller, R.Allen; Ahuett-Garza, Horacio; Choudhury, Aswin K.; Dedhia, Sanjay

    1998-05-01

    The objective of this work was to develop and test die casting design evaluation techniques based on the visualization of geometric data that is related to potential defects or problems. Specifically, thickness information is used to provide insight into potential thermal problems in the part and die. Distance from the gate and a special type of animation of the fill pattern is used to provide an assessment of gate, vent and overflow locations. Techniques have been developed to convert part design information in the form of STL files to a volume-based representation called a voxel model. The use of STL files makes the process CAD system independent. Once in voxel form, methods that were developed in this work are used to identify thick regions in the part, thin regions in the part and/or die, distance from user specified entry locations (gates), and the qualitative depiction of the fill pattern. The methods were tested with a prototype implementation on the UNIX platform. The results of comparisons with numerical simulation and field reported defects were surprisingly good. The fill-related methods were also compared against short-shots and a water analog study using high speed video. The report contains the results of the testing plus detailed background material on the construction of voxel models, the methods used for displaying results, and the computational geometric reasoning methods used to create die casting-related information from the voxel model for display to the user.

  10. Accidental Implant Screwdriver Ingestion: A Rare Complication during Implant Placement

    PubMed Central

    Jain, Anshul; Baliga, Shridhar D

    2014-01-01

    One of the complications during a routine dental implant placement is accidental ingestion of the implant instruments, which can happen when proper precautions are not taken. Appropriate radiographs should be taken to locate the correct position of foreign body; usually the foreign body passes asymptomatically from gastrointestinal tract but sometimes it may lead to intestinal obstruction, perforations and impactions. The aim of this article is to report accidental ingestion of 19 mm long screw driver by a senile patient. PMID:25628702

  11. [From absolute necessity of dying to preventive planning of dying? The change of social and medicine debates on dying in the 1980s].

    PubMed

    Jordan, I

    2010-04-01

    International euthanasia debates focussing on "autonomous dying" in the 1980s corresponded with a general change in the health-care system: availability of new technical means with an analogous medical-ethic understanding of human suffering and dying. This change is part of a general development from "passive health consumption" to "active prevention" in our society.

  12. The smooth entropy formalism for von Neumann algebras

    NASA Astrophysics Data System (ADS)

    Berta, Mario; Furrer, Fabian; Scholz, Volkher B.

    2016-01-01

    We discuss information-theoretic concepts on infinite-dimensional quantum systems. In particular, we lift the smooth entropy formalism as introduced by Renner and collaborators for finite-dimensional systems to von Neumann algebras. For the smooth conditional min- and max-entropy, we recover similar characterizing properties and information-theoretic operational interpretations as in the finite-dimensional case. We generalize the entropic uncertainty relation with quantum side information of Tomamichel and Renner and discuss applications to quantum cryptography. In particular, we prove the possibility to perform privacy amplification and classical data compression with quantum side information modeled by a von Neumann algebra.

  13. Henry Cavendish, Johann von Soldner, and the deflection of light

    NASA Astrophysics Data System (ADS)

    Will, Clifford M.

    1988-05-01

    The gravitational deflection of light based on Newtonian theory and the corpuscular model of light was calculated, but never published, around 1784 by Henry Cavendish, almost 20 years earlier than the first published calculation by Johann Georg von Soldner. The two results are slightly different because, while Cavendish treated a light ray emitted from infinity, von Soldner treated a light ray emitted from the surface of the gravitating body. At the first order of approximation, they agree with each other; both are one-half the value predicted by general relativity and confirmed by experiment.

  14. Endothelial dysfunction in von Willebrand disease: angiogenesis and angiodysplasia.

    PubMed

    Randi, Anna M

    2016-05-01

    In recent years, new functions for the haemostatic protein von Willebrand Factor (VWF) have emerged. Amongst these is the ability to modulate the development of new blood vessels, a process called angiogenesis. The subtle effects that VWF exerts on blood vessel formation and stability may be relevant for the small but significant fraction of patients with von Willebrand disease (VWD) who also present with vascular malformations (angiodysplasia) in the gastrointestinal tract, often responsible for intractable bleeding. This review will briefly summarise the evidence and discuss the molecular pathways involved.

  15. An Accurate von Neumann's Law for Three-Dimensional Foams

    SciTech Connect

    Hilgenfeldt, Sascha; Kraynik, Andrew M.; Koehler, Stephan A.; Stone, Howard A.

    2001-03-19

    The diffusive coarsening of 2D soap froths is governed by von Neumann's law. A statistical version of this law for dry 3D foams has long been conjectured. A new derivation, based on a theorem by Minkowski, yields an explicit analytical von Neumann's law in 3D which is in very good agreement with detailed simulations and experiments. The average growth rate of a bubble with F faces is shown to be proportional to F{sup 1/2} for large F , in contrast to the conjectured linear dependence. Accounting for foam disorder in the model further improves the agreement with data.

  16. The smooth entropy formalism for von Neumann algebras

    SciTech Connect

    Berta, Mario; Furrer, Fabian; Scholz, Volkher B.

    2016-01-15

    We discuss information-theoretic concepts on infinite-dimensional quantum systems. In particular, we lift the smooth entropy formalism as introduced by Renner and collaborators for finite-dimensional systems to von Neumann algebras. For the smooth conditional min- and max-entropy, we recover similar characterizing properties and information-theoretic operational interpretations as in the finite-dimensional case. We generalize the entropic uncertainty relation with quantum side information of Tomamichel and Renner and discuss applications to quantum cryptography. In particular, we prove the possibility to perform privacy amplification and classical data compression with quantum side information modeled by a von Neumann algebra.

  17. Weibel-Palade bodies: a window to von Willebrand disease.

    PubMed

    Valentijn, K M; Eikenboom, J

    2013-04-01

    Weibel-Palade bodies (WPBs) are the storage organelles for von Willebrand factor (VWF) in endothelial cells. VWF forms multimers that assemble into tubular structures in WPBs. Upon demand, VWF is secreted into the blood circulation, where it unfolds into strings that capture platelets during the onset of primary hemostasis. Numerous mutations affecting VWF lead to the bleeding disorder von Willebrand disease. This review reports the recent findings on the effects of VWF mutations on the biosynthetic pathway of VWF and its storage in WPBs. These new findings have deepened our understanding of VWF synthesis, storage, secretion, and function.

  18. Occlusion on oral implants: current clinical guidelines.

    PubMed

    Koyano, K; Esaki, D

    2015-02-01

    Proper implant occlusion is essential for adequate oral function and the prevention of adverse consequences, such as implant overloading. Dental implants are thought to be more prone to occlusal overloading than natural teeth because of the loss of the periodontal ligament, which provides shock absorption and periodontal mechanoreceptors, which provide tactile sensitivity and proprioceptive motion feedback. Although many guidelines and theories on implant occlusion have been proposed, few have provided strong supportive evidence. Thus, we performed a narrative literature review to ascertain the influence of implant occlusion on the occurrence of complications of implant treatment and discuss the clinical considerations focused on the overloading factors at present. The search terms were 'dental implant', 'dental implantation', 'dental occlusion' and 'dental prosthesis'. The inclusion criteria were literature published in English up to September 2013. Randomised controlled trials (RCTs), prospective cohort studies and case-control studies with at least 20 cases and 12 months follow-up interval were included. Based on the selected literature, this review explores factors related to the implant prosthesis (cantilever, crown/implant ratio, premature contact, occlusal scheme, implant-abutment connection, splinting implants and tooth-implant connection) and other considerations, such as the number, diameter, length and angulation of implants. Over 700 abstracts were reviewed, from which more than 30 manuscripts were included. We found insufficient evidence to establish firm clinical guidelines for implant occlusion. To discuss the ideal occlusion for implants, further well-designed RCTs are required in the future.

  19. Persistent Left Superior Vena Cava in Patients Undergoing Cardiac Device Implantation: Clinical and Long-Term Data

    PubMed Central

    Petrac, Dubravko; Radeljic, Vjekoslav; Pavlovic, Nikola; Manola, Sime; Delic-Brkljacic, Diana

    2013-01-01

    Background Persistent left superior vena cava (LSVC) is a rare congenital venous anomaly that may be found at the time of cardiac device lead insertion. Methods In this case series, we present clinical and long-term data of five patients with LSVC who underwent pacemaker (PM) or cardioverter defibrillator (ICD) implantation during the period of 10 years. Results Left-sided venous approach was used for device implantation in 3 patients with standard PM indications, whereas a right-sided venous approach and an epicardial approach had to be used in 2 patients who needed an ICD and biventricular PM, respectively. In post implantation period of 44 ± 29 months, one patient died due to stroke, one underwent heart transplantation, and 3 had atrial fibrillation. Conclusion The long-term outcome of patients with persistent LSVC and implanted cardiac devices is mostly influenced by the presence of underlying heart disease.

  20. The dying role: its relevance to improved patient care.

    PubMed

    Noyes, R; Clancy, J

    1977-02-01

    Society is failing to meet the obligation it has to its dying members. Persons with terminal illnesses suffer isolation and neglect in hospitals, receive overzealous treatment by physicians, and are kept in ignorance of their situation by families and medical personnel. Evidence for these statements has come from observers of the medical care system and from dying patients themselves (Kübler-Ross, 1969; Reynolds and Kalish, 1974; Sudnow, 1967); In the nineteenth century it was common for persons to die in the familiar environs of their homes, surrounded by grieving families from whom they parted in a meaningful manner (Blauner, 1966). Dying persons of today no longer fill a well-defined social role. Instead, the distinction between the roles of sick and dying persons has been lost and, in the resulting confusion, the care of dying people has suffered. The purpose of this article is to clarify the distinction between the dying and sick roles, identify the signs of existing role confusion, suggest ways in which this confusion may be corrected, and show how reestablishment of the dying role can result in improved care of dying people. The important part physicians play in defining sick and dying roles will be emphasized.