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  • 1
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 67 (1990), S. 4456-4458 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The spin dependence of L2,3 absorption in 5d atoms oriented in a ferromagnetic matrix contains information on the spin density of the empty d-projected states of the absorbing atom. Spin-dependent absorption spectroscopy using circularly polarized synchrotron radiation was applied to study the polarization of the Pt atoms in the binary alloy Co50Pt50 and Pt/Co layered structures, which are promising candidates for magneto-optical recording. The spin-dependent absorption signals for vapor-deposited 250(4 A(ring) Co+18 A(ring) Pt) and 250(6 A(ring) Co+18 A(ring) Pt) multilayers indicate a ferromagnetic coupling on Pt and Co atoms with a significant Pt polarization. This is reduced on average by about 60% with respect to the Pt polarization in the Co50Pt50 alloy. The experimental results are discussed on the basis of spin-polarized band-structure calculations.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    International journal of flexible manufacturing systems 4 (1992), S. 129-158 
    ISSN: 1572-9370
    Keywords: robot ; cell ; machine tending ; recursion model ; transient operations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract This article presents an efficient algorithm for applying the recursion modeling approach to describe the transient operation of cellular production/assembly systems that incorporate features such as finite buffers, job-shop routing, lot sequencing, and material handling. Tests evaluate the approximation method relative to number of machines at a station, capacity of input/output buffers, degree of balance among station processing times, and sequencing rule. Furthermore, the method is demonstrated in application to a hypothetical industrial setting that involves the assembly of electronic circuit cards in a facility composed of several cells. All tests indicate that the method gives accurate estimates of transient performance within reasonable runtime. In comparison with earlier recursion models, this research incorporates a number of new features (see list above), improves the accuracy of approximation, and facilitates implementation with a new, more efficient algorithm.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Queueing systems 17 (1994), S. 471-490 
    ISSN: 1572-9443
    Keywords: Kitting ; assembly ; Markov renewal process ; double-ended queue
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract In small-lot, multi-product, multi-level assembly systems, kitting (or accumulating) components required for assembly plays a crucial role in determining system performance, especially when the system operates in a stochastic environment. This paper analyzes the kitting process of a stochastic assembly system, treating it as an assembly-like queue. If components arrive according to Poisson processes, we show that the output stream departing the kitting operation is a Markov renewal process. The distribution of time between kit completions is also derived. Under the special condition of identical component arrival streams having the same Poisson parameter, we show that the output stream of kits approximates a Poisson process with parameter equal to that of the input stream. This approximately decouples assembly from kitting, allowing the assembly operation to be analyzed separately.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 308 (1982), S. 103-105 
    ISSN: 1434-601X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Muonic Coulomb capture ratios for 35 fluorides and 13 sulfides have been measured at SIN, Switzerland. We observed a periodic variation with the atomic numberZ of the cation. This is in agreement with recent theoretical calculations.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 300 (1981), S. 253-262 
    ISSN: 1434-601X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Muonic X-ray spectra of 32 chlorides have been measured with Ge detectors. Coulomb capture ratios and Lyman X-ray intensities were determined, and correlations to target data established. The experimental capture ratios agree well with the values from a recently proposed formula.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1432-055X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1432-055X
    Keywords: Schlüsselwörter Remifentanil/Propofol ; Sevofluran/Fentanyl ; Frühe postoperative kognitive Störungen ; Key words Remifentanil/propofol ; Sevoflurane/fentanyl ; Early postoperative cognitive impairment
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Abstract Objective: In ambulatory anaesthesia the time required to recover from cognitive impairment should be as short as possible. The aim of this study was to compare the early cognitive recovery after remifentanil/propofol (R/P) and sevoflurane/fentanyl (S/F) anaesthesia. Methods: Sixty patients scheduled for elective gynaecological laparoscopy and 24 female volunteers tested for the assessment of learning effects were investigated. After praemedication with midazolam anaesthesia was induced with propofol, atracurium and either 1 μg/kg fentanyl or 1 μg/kg remifentanil. For maintenance 0.25 μg/kg/min remifentanil and 0.6 mg/kg/min propofol (R/P) or 1.7 vol% sevoflurane (S/F) were given. Both groups were ventilated with 30% oxygen in air and received metamizol for postoperative analgesia. Verbal Learning Test, Stroop Colour and Word Interference Test, Digit Symbol Substitution Test and Four Boxes Test were performed the day before surgery and 30 min, 1 h, 2 h and 4 h after termination of anaesthesia. Results: For remifentanil/propofol cognitive function was still impaired 2 h (Verbal Learning) and 4 h (Stroop, Digit Symbol Substitution and Four Boxes Test) after termination of anaesthesia. After sevoflurane/fentanyl anaesthesia cognitive impairment lasted the same duration in Four Boxes Test, but shorter in Stroop and Digit Symbol Substitution and could not be found in Verbal Learning Test. Conclusion: The duration of cognitive impairment in the early postoperative period differed by the test procedures and the anaesthetic procedures used in this investigation. Recovery appeared to be faster after sevoflurane/fentanyl than after remifentanil/propofol at least in aspects of cognitive function.
    Notes: Zusammenfassung Fragestellung: Schnelles Erwachen und eine rasche Erholung der kognitiven Funktionen gehören zu den wesentlichen Auswahlkriterien von Anästhetika für ambulante Eingriffe. Die vorliegende Untersuchung befasst sich mit der Frage, ob die Erholung kognitiver Funktionen nach einer TIVA mit Remifentanil/ Propofol (P/R) rascher erfolgt als nach einer balancierten Anästhesie mit Sevofluran/Fentanyl (S/F). Methodik: Die Untersuchung erfolgte an 60 Patientinnen (ASA I–II, 18–65 Jahre), die sich einer elektiven gynäkologisch-laparoskopischen Operation unterzogen sowie an 24 Probandinnen zur Erfassung narkoseunabhängiger Lerneffekte. Die Prämedikation erfolgte mit Midazolam, die Narkoseeinleitung mit Propofol und Atracurium. Gemäß Gruppenzuteilung wurden für die Narkose randomisiert entweder 1 μg/kg Fentanyl und 1,7 Vol.-% Sevofluran oder 0,25 μg/kg/min Remifentanil und 0,06 mg/kg/min Propofol zugeführt. Beatmet wurde mit 30% 02 in Luft, die postoperative Analgesie erfolgte mit Metamizol. An Testverfahren zur Erfassung kognitiver Funktionen wurden Worte-Lernen-, Stroop Farb-Wort-, Buchstaben-Ziffern-Ersetzen- und Vier-Felder-Test am Vortag der Operation und 30 min, 1 h, 2 h und 4 h postoperativ durchgeführt. Ergebnisse: Nach Remifentanil/Propofol fanden sich signifikante kognitive Störungen bis zu 2 h (Worte-Lernen-Test) und 4 h (Stroop- und Buchstaben-Ziffern-Ersetzen-Test, Vier-Felder-Test) nach Anästhesieende. Nach Sevofluran/Fentanyl dauerten die kognitiven Störungen im Vier-Felder-Test gleich lange an, im Stroop- und im Buchstaben-Ziffern-Ersetzen-Test hingegen kürzer, während im Worte-Lernen-Test bereits nach 30 min keine Störungen mehr nachweisbar waren. Schlussfolgerung: Die Dauer kognitiver Störungen in der frühen postoperativen Phase unterscheidet sich in Abhängigkeit vom verwendeten Anästhesieverfahren und vom jeweiligen Testverfahren. Zumindest in Teilaspekten der kognitiven Funktion scheint die Beeinträchtigung nach total intravenöser Anästhesie mit Remifentanil und Propofol länger anzuhalten als nach balancierter Anästhesie mit Sevofluran und Fentanyl. Für ambulante Eingriffe ist bedeutsam, dass in beiden Gruppen auch nach 4 h keine vollständige Erholung stattgefunden hat.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Der Anaesthesist 43 (1994), S. 26-29 
    ISSN: 1432-055X
    Keywords: Schlüsselwörter: Spinalanästhesie – Säuglinge – Adrenalin – Bupivacain – Wirkdauer ; Key words: Spinal anaesthesia – Pre-term infant – Epinephrine – Bupivacaine – Duration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Abstract. The duration of spinal anaesthesia in infants is short compared to adult patients. When tetracaine is used, the addition of epinephrine significantly prolongs the duration. For bupivacaine, however, the influence of epinephrine on the duration is not clear. We investigated the effects of epinephrine 1: 200 000 added to bupivacaine 0.5% on duration and haemodynamics. Patients and Methods. Ten former pre-term infants with postnatal respiratory problems, scheduled for bilateral inguinal hernia repair, were enrolled in the study after informed parental consent had been obtained. The infants were fasted at least 4 h prior to surgery. If they did not receive i.v. infusions before surgery, a bolus of 10 ml/kg Ringer's acetate was injected after inserting the i.v. cannula, followed by a continuous infusion of 8 ml/kg 2/3 N NaCl with 5% dextrose. Spinal anaesthesia was performed in a sitting position with 0.6 ml bupivacaine 0.5%. Five patients received plain bupivacaine (group I) and five bupivacaine with epinephrine 1: 200 000 (group II). Heart rate registered by ECG and non-invasive blood pressure were recorded prior to positioning the baby for lumbar puncture and 2, 5, 10, and 20 min after injection of bupivacaine. The duration of spinal anaesthesia was defined as the time from injection to the time when the first movements of the legs were observed after stimulation. For testing statistical differences the U test was used between the groups and the Wilcoxon and Wilcox test within the groups. Results (expressed as median and range). Additional epinephrine significantly prolonged the duration of spinal anaesthesia (group II: 95 min [60 – 120] vs group I: 50 min [37 – 85]). Haemodynamic parameters did not differ at any time between or within the groups. In group I, one infant had high spinal anaesthesia with impaired respiration but without cardiovascular effects; after 10 min of assisted ventilation by mask, sufficient respiration as judged by pulse oximetry and clinical observation had returned. The duration of spinal anaesthesia in this child was 60 min. Conclusions. Epinephrine 1: 200 000 significantly prolongs the duration of spinal anaesthesia in former preterm infants. Haemodynamic parameters in this age group remain unchanged during spinal anaesthesia and are not influenced by the addition of epinephrine.
    Notes: Zusammenfassung. Bei 10 ehemaligen Frühgeborenen mit einem Gestationsalter zwischen 38 und 48 Wochen am Operationstag und einem Gewicht zwischen 2,10 und 3,22 kg, die postpartal respiratorische Adaptationsstörungen aufwiesen, wurde nach elterlichem Einverständnis eine Spinalanästhesie mit 0,6 ml Bupivacain 0,5% für eine Leistenhernienoperation durchgeführt. Jeweils 5 Patienten erhielten Bupivacain ohne Adrenalinzusatz (Gruppe I) bzw. mit Adrenalin 1: 200 000=5 µg/ml (Gruppe II). Die Wirkdauer wurde definiert als Zeit von der Injektion bis zur ersten Bewegung der Beine: Die über das EKG registrierte Herzfrequenz und die oszillometrisch gemessenen Blutdruckwerte wurden vor Lagerung zur Lumbalpunktion sowie 2, 5, 10 und 20 min nach der Injektion des Lokalanästhetikums erhoben. Die Wirkdauer einer Spinalanästhesie war im Median in der Gruppe II mit 95 min (60 – 120) signifikant länger als in der Gruppe I mit 50 min (37 – 85). Keine signifikanten Unterschiede zeigten sich bei Herzfrequenz und Blutdruckwerten – weder zwischen den Gruppen noch im zeitlichen Verlauf einer Gruppe.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Cellular and molecular life sciences 37 (1981), S. 1160-1162 
    ISSN: 1420-9071
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary WhenNaegleria fowleri (Lee) was incubated in newborn calf and human serum an amebicidal effect was observed. Heat inactivation of both sera resulted in the recovery of viable amebae after incubation in these sera. Exogenous iron added to non-heat inactivated calf serum improved viability slightly but was without effect when added to human serum not heat inactivated. Exogenous iron greatly enhanced growth and/or viability in heat inactivated calf serum. Viability of amebae also was considerably enhanced in human serum which was heat inactivated when pH was lowered in conjunction with iron supplements.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Histochemistry and cell biology 41 (1974), S. 161-166 
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ability of polyanionic substances such as heparin, chondroitin sulfate, dextran sulfate, polyanethol sulfonic acid and polyvinyl sulfate in preventing the aggregation of constituents of the light mitochondrial fraction of rat liver at pH 3.0, 5.0 and 7.0 was investigated. The polyanions were found to act as potent agents in preventing the aggregation and disruption of the particles as shown by light scattering measurements and electronmicroscopy.
    Type of Medium: Electronic Resource
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