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  • 1
    Electronic Resource
    Electronic Resource
    s.l. ; Stafa-Zurich, Switzerland
    Solid state phenomena Vol. 54 (Aug. 1997), p. 65-74 
    ISSN: 1662-9779
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Physics
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Electrical engineering 77 (1994), S. 213-219 
    ISSN: 1432-0487
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Description / Table of Contents: Contents Growing concern with environmental pollution encourages renewed investigations in the field of electrically driven vehicles. The most significant drawback of electrical drive systems as applied to autonomous vehicles is their need for a continuous electrical power supply, mostly provided by electrochemical storage batteries. However, due to physical limitations their power and energy capacity is poor compared to liquid fuel. An alternative can be seen in the use of an on-board power supply, with a generator driven by a thermal prime mover. In this case the battery serves only as short-time energy buffer with reduced capacity, weight and cost, whereas the mean electrical power is directly fed from the generator to the electrical drive of the vehicle. In this investigation the use of a high-speed generator, that might be directly coupled to a gas turbine, is proposed to reduce volume and weight of the on-board power supply. This paper deals only with the electromechanical part of the power supply. Experimental results from a generator system rated 10 kW at 36 000 rpm are discussed.
    Notes: Übersicht Wegen zunehmender Umweltbelastungen gibt es wieder verstärkte Entwicklungsanstrengungen zugunsten elektrisch angetriebener Fahrzeuge. Der wesentliche Nachteil autonomer elektrisch angetriebener Fahrzeuge besteht nach wie vor in deren Abhängigkeit von einer kontinuierlichen elektrischen Energiequelle, die in den meisten Fällen durch eine elektrochemische Speicherbatterie bereitgestellt wird. Aufgrund physikalischer Beschränkungen bleibt deren Leistungsdichte und Kapazität jedoch weit hinter der von flüssigen Kraftstoffen zurück. Eine mögliche Alternative besteht in der Verwendung einer Bordstromversorgung, mit einem Generator der durch eine thermische Kraftmaschine angetrieben wird. In diesem Fall dient die Batterie nur als Kurzzeitspeicher, was deren Kosten, Gewicht und Preis wesentlich reduziert. Der Mittelwert der elektrischen Leistung kann direkt vom Generator zum elektrischen Fahrantrieb geführt werden. Um Gewicht und Volumen der Bordstromversorgung zu reduzieren, wird im folgenden die Verwendung eines schnellaufenden Generators, der direkt an eine Gasturbine gekoppelt werden könnte, vorgeschlagen. Der Aufsatz befaßt sich ausschließlich mit dem elektromechanischen Teil der Bordstromversorgung. Experimentelle Ergebnisse mit einem Generatorsystem im Leistungsbereich von 10 kW bei 36 000 min−1 werden vorgestellt.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Intensive care medicine 25 (1999), S. 640-641 
    ISSN: 1432-1238
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Zeitschrift für Herz-, Thorax- und Gefässchirurgie 13 (1999), S. 126-132 
    ISSN: 0930-9225
    Keywords: Schlüsselwörter Lungeninfektion, mykotische – Aspergillom, pulmonales – Diagnostik – Symptomatik – Therapie, operative ; Key words Mycotic pulmonary infection – pulmonary aspergillosis – diagnosis – symptoms – surgical treatment – results
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary In Europe, saprophytic pulmonary aspergillosis represents the only mycotic infection relevant for thoracic surgery. From the pathogenetic point of view, it is a colonization of preexisting lung or pleural cavities following other severe pulmonary diseases. The incidence amounts to 0.4% among patients in a special hospital for pulmonary diseases. Concerning this review, the diagnosis is based on histologic examination for all 66 patients we operated on between 1961 and 1996. Preoperative proof of the fungal infection remains difficult. The majority of patients (77%) are male. There is a correlation between cigarette smoking and abuse of alcohol on the one hand and the incidence of the disease on the other hand. A higher incidence of saprophytic pulmonary aspergillosis was found for people working in agriculture, in the building trade, and in paper mills. Pulmonary tuberculosis and pneumonia were present in the past history in 47% of the patients. Usually, the tentative diagnosis is based on chest x-ray, especially if hemoptysis is present. Major hemoptysis is the most severe and most dangerous complication caused by aspergilloma. Clinical presentation and chest x-ray findings are non-characteristic. Nowadays, the typical x-ray of pulmonary aspergilloma, almost always localized in the upper lobes, became a rare finding. If an aspergillus infection is suspected, serologic methods are reliable and sensitive. A surgical procedure is absolutely indicated in patients with major hemoptysis in their history, in case of disease progression or indeterminate mass and in order to avoid fungal dissemination. If a saprophytic aspergillosis is suspected according to radiologic findings, clinical examination, and patient's social history, an operation is justified. Relative surgical indications are hepatotoxic and carcinogenic effects of the mycotoxins. The lobectomy, if necessary carried out as pleuro-lobectomy, is the adequate resection in most patients (68%). However, this operation is technically demanding and it usually requires a longer operating time as compared to lobectomies for other underlying diseases. Peri- and postoperative complications occur in 60% of resections for pulmonary aspergilloma. A higher incidence of postoperative complications was found for smaller resections, like segmentectomies or wedge resections, as compared to lobectomies. Persistent pleural space problems connected with a prolonged stay in the hospital remains the main problem. It requires a primary or secondary thoracoplasty in a number of patients. The operative mortality rate is 3%. A systemic antifungal therapy is not an appropriate treatment for saprophytic pulmonary aspergillosis and can even cause specific complications.
    Notes: Zusammenfassung Einzige chirurgisch relevante thorakale Pilzinfektion ist in unseren Breiten die Aspergillose. Sie ist eine opportunistische Infektion im Gefolge anderer Lungen- und Pleuraläsionen. Die Inzidenz beträgt im Krankengut einer thoraxchirurgischen Spezialklinik 0,4%. In allen 66 Fällen der Jahre 1961 – 1966 liegt eine definitive histopathologische Diagnose vor. Präoperativ gelingt selten der Pilznachweis. Mit 77% sind Männer im mittleren Lebensalter häufiger betroffen als Frauen. Die Infektion korreliert mit exzessivem Nikotin- und Alkoholabusus. Bevorzugt sind Beschäftigte der Landwirtschaft, des Baugewerbes und im Umgang mit Papier Tätige befallen. Je 47% der Patienten hatten anamnestisch eine Lungentuberkulose bzw. Pneumonie. Konventionelle Radiomorphologie erbringt oft den Verdacht, insbesondere in Verbindung mit Hämoptysen. Sie sind die häufigste und gefährlichste Komplikation der unbehandelten Aspergillose. Klinik und Radiomorphologie sind uncharakteristisch. Das klassische Röntgenbild des “Myzetoms” ist heute nur selten zu erwarten. Fast ausnahmslos sind Aspergillome in den Oberlappen lokalisiert. Bei Verdacht haben serologische Untersuchungen eine hohe Sensitivität. Der zwingende Verdacht auf eine Aspergillose auf der Basis von radiologischen, klinischen und sozialen Indizien rechtfertigt bei fehlenden Kontraindikationen die operative Therapie. Absolute Operationsindikationen sind überstandene oder aktuelle Hämoptoe, drohende Pilzdissemination, Tumorverdacht und Befundprogredienz. Eine relative Indikation ergibt sich durch die lebertoxische und karzinogene Wirkung von Mykotoxinen. In den meisten Fällen (68%) ist eine Lobektomie, oft als Pleurolobektomie ausgeführt, ein adäquater Eingriff. Er ist dennoch technisch anspruchsvoll und benötigt in der Regel längere Zeiten als bei anderen Indikationen. Teilresektionen aus einem Lappen sind mit erhöhter Komplikationsrate belastet. Sie ist ohnehin schon hoch (60%). Hauptproblem ist der persistierende pleurale Hohlraum, der zu langer Hospitalisationszeit führt, und der oft mit einer primären oder sekundären Plastik beseitigt werden muß. Die OP-Letalität beträgt 3%. Systemische Therapie birgt zusätzliche Gefahren in sich und kann die opportunistische Infektion nicht beherrschen.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Zeitschrift für Herz-, Thorax- und Gefässchirurgie 13 (1999), S. 37-45 
    ISSN: 0930-9225
    Keywords: Schlüsselwörter Trachea – primäre Tumoren – chirurgische Therapie – Ergebnisse – Prognose ; Key words Trachea – primary tumors – surgical therapy – results – prognosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Although a variety of histologic entities were described, primary tumors of the trachea are rare findings. Over a period of 20 years, 30 patients underwent 31 tracheal resections in two hospitals for thoracic surgery. Among them 4 patients had thyroid carcinoma involving the trachea. In these patients a strumectomy combined with tracheal resection was performed. One re-operation for erosion bleeding of the innominate artery on the 8th postoperative day was successfully performed. All patients showed excellent long-term survival. Fifteen of primary treacheal tumors involved the distal trachea including the carina; 8 of these patients had squamous cell carcinoma. Eight of the 15 patients underwent carinal resection alone without loss of pulmonary parenchyma. These patients showed a regular postoperative course with a 5-year survival of 100%. Three years after carinal resection, one patient had radiotherapy for local recurrence of carcinoid tumor involving a subcarinal lmyphonode. In 3 of the 15 patients, sleeve pneumonectomies were indicated. Two of these patients died postoperatively accounting for a 30-day mortality of 6.7% (2/31). Twelve primary tracheal tumors involved the cervical and upper mediastinal trachea (squamous cell carcinoma n=1, adenoid cystic carcinoma n=4, local recurrence of adenoid cystic carcinoma n=1, carcinoid n=4, neurinoma n=2). In 7 cases a window shaped resection of the trachea was performed, using a skin flap (n=5) or pericard patch (n=2) for closure of the defect. These patients had no postoperative complications and showed an excellent longterm survival. Postoperative complications occurred in 19.4% (6/31): death (n=2), erosion bleeding of the innominate artery (n=1), partial temporary dehiscences of cervical anastomosis with secondary closure like a tracheostoma (n=2), and stenosis of tracheal anastomosis (n=1), which could be controlled by bouginage. For the whole group of the 26 patients with malign tumors 5- and 10-year survival rates were 44% and 28%, respectively. Our experiences support an aggressive surgical approach.
    Notes: Zusammenfassung Trotz der histologischen Vielfalt der bisher bekannten Tracheatumoren sind sie praktisch sehr selten. In zwei thoraxchirurgischen Kliniken sahen wir in 20 Jahren nur 30 Patienten, bei denen 31 Operationen vorgenommen wurden. Vier von ihnen hatten ein infiltrierend wachsendes Schilddrüsenkarzinom, das jeweils mit Strumektomie und Tracheamanschettenresektion mit End-zu-End-Anastomose beseitigt wurde. Eine postoperative Trunkus-brachiocephalicus-Arrosionsblutung am 8. Tag wurde erfolgreich behandelt. Alle vier Patienten haben langfristig überlebt. Unter 27 primären Tumorläsionen der Trachea betrafen 15 den Bifurkationsbereich. 8 von diesen waren Plattenepithelkarzinome. Von 15 Bifurkationsresektionen konnten 8 ohne Lungenopfer erfolgen. Dabei gab es keine Komplikationen. Alle Patienten leben über 5 Jahre – ein Patient hatte 3 Jahre nach Bifurkationsresektion wegen Karzinoids ein subkarinales Lymphknotenrezidiv und wurde einer Radiatio unterzogen. 3 Bifurkationsresektionen erfolgten mit Pneumonektomie (sleeve pneumonectomy) rechts (n=2) und links (n=1). Zwei dieser Patienten stellen mit 6,7% die 30-Tage-Operationsletalität. Obere und mittlere Trachea waren in 12 Fällen von einem primären Tumor betroffen (1 Plattenepithelkarzinom, 4 adenoidzystische Karzinome und 1 Rezidiv, 4 Karzinoide, 2 Neurinome). In 7 Fällen erfolgte eine Fensterung und die Defektdeckung mit Kutislappen (n=5) oder Perikard-Patch (n=2). Diese Patienten wiesen keine Komplikationen auf und leben langfristig. Die Komplikationsrate aller 31 Eingriffe beträgt 19,4% (n=6): Neben den Exitusfällen und der Trunkusarrosion gab es 2 passagere partielle zervikale Nahtinsuffizienzen, die sich unter Tamponade wie ein Tracheostoma sekundär schlossen, und 1 Anastomosenstenose, die erfolgreich bougiert wurde. 5 bzw. 10 Jahre überlebten 44 bzw. 28% der Patienten mit malignen Tumoren. Unsere Erfahrungen sprechen für ein aggressives chirurgisches Vorgehen.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 96 (1992), S. 7352-7363 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Low frequency Raman spectra (5–50 cm−1) show very obvious effects of disorder in the glass, and of the changes in the system which occur at the liquid–glass transition. Yet this frequency range has been considered in only very few glass formers. Here we report on this frequency range for the glass former system GeSBr2 which constitutes a statistically interrupted network. The temperature range studied was from far below the glass transition temperature (Tg=−30 °C) to well above it (T=−168 °C to +71 °C). In the glass, the loss of q conservation for phonon observation (due to static disorder) leads to a broad inelastic scattering peak around 10–15 cm−1, the so-called boson peak. The Raman spectrum is interpreted in terms of a correlation length Rc of phonon propagation and of phonon–photon-coupling; Rc is a measure of intermediate range order and amounts to ∼10 A(ring), independent of temperature. As T is raised, the minimum between this peak and the elastic peak is gradually filled up due to fast dynamic processes which increase rapidly above Tg. This scattering is interpreted in terms of fast dynamical processes, and the connection is made to the dynamical aspects of the liquid–glass transition. The strength and the time constants of fast processes are discussed in terms of two phenomenological models; both models describe the observed spectra well using a small number of parameters. The relaxation time found for the fast dynamical process (10−11–10−12 s) is in rough agreement with the value found independently in Brillouin scattering.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 80 (1996), S. 2990-2993 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The two possible causes of depth inhomogeneities of the microstructure of porous silicon are changes in the HF concentration with depth and a varying chemical etching rate of the porous silicon layer. During anodization chemical etching will become important for microporous silicon — e.g. p-porous silicon — due to the large internal surface area, especially at long etching times. On the other hand, a considerable decrease of the HF concentration will occur during etching with high current densities to produce p+-porous silicon with high porosities. We have investigated the depth inhomogeneity of porous silicon layers by spectroscopic ellipsometry, Raman spectroscopy and photoluminescence measurements. From a line shape analysis of the Raman signal a size distribution of nanocrystals is deduced. For p-porous silicon smaller nanocrystals are found near the surface of the layer; for p+-porous silicon etched with high current densities smaller nanocrystals are found near the porous silicon/substrate interface. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Schizophrenia is a major psychiatric disease, which affects the centre of the personality, with severe problems of perception, cognition as well as affective and social behaviour. In cerebrospinal fluid of drug-free schizophrenic patients, a significant decrease in the level of total glutathione (GSH) by 27% (P 〈 0.05) was observed as compared to controls, in keeping with the reported reduced level of its metabolite γ-glutamylglutamine. With a new non-invasive proton magnetic resonance spectroscopy methodology, GSH level in medial prefrontal cortex of schizophrenic patients was found to be 52% (P = 0.0012) lower than in controls. GSH plays a fundamental role in protecting cells from damage by reactive oxygen species generated among others by the metabolism of dopamine. A deficit in GSH would lead to degenerative processes in the surrounding of dopaminergic terminals resulting in loss of connectivity. GSH also potentiates the N-methyl-d-aspartate (NMDA) receptor response to glutamate, an effect presumably reduced by a GSH deficit, leading to a situation similar to the application of phencyclidine (PCP). Thus, a GSH hypothesis might integrate many established biological aspects of schizophrenia.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of cardiac surgery 15 (2000), S. 0 
    ISSN: 1540-8191
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract Objectives: The study describes the single-center experience using robot-assisted videoscopic mitral valve surgery and the early results with a remote telemanipulator-assisted approach for mitral valve repair. Material and Methods: Out of a series of 230 patients who underwent minimally invasive mitral valve surgery, in 167 patients surgery was performed with the use of robotic assistance. A voice-controlled robotic arm was used for videoscopic guidance in 152 cases. Most recently, a computer-enhanced telemanipulator was used in 15 patients to perform the operation remotely. Results: The mitral valve was repaired in 117 and replaced in all other patients. The voice-controlled robotic arm (AESOP 3000) facilitated videoscopic-assisted mitral valve surgery. The procedure was completed without the need for an additional assistant as “solo surgery.” Additional procedures like radiofrequency ablation and tricuspid valve repair were performed in 21 and 4 patients, respectively. Duration of bypass and clamp time was comparable to conventional procedures (107 Å 34 and 50 Å 16 min, respectively). Hospital mortality was 1.2%. Using the da Vinci telemanipulation system, remote mitral valve repair was successfully performed in 13 of 15 patients. Conclusion: Robotic-assisted less invasive mitral valve surgery has evolved to a reliable technique with reproducible results for primary operations and for reoperations. Robotic assistance has enabled a solo surgery approach. The combination with radiofrequency ablation (Mini Maze) in patients with chronic atrial fibrillation has proven to be beneficial. The use of telemanipulation systems for remote mitral valve surgery is promising, but a number of problems have to be solved before the introduction of a closed chest mitral valve procedure.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    British journal of dermatology 146 (2002), S. 0 
    ISSN: 1365-2133
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Type of Medium: Electronic Resource
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