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  • 1
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 63 (1992), S. 3112-3119 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: We describe a system of capacitive transducers applied to two free falling objects with the aim of detecting differential accelerations due to nonNewtonian components. The two objects have a cylindrical shape to minimize the systematic errors and they fall in a microgravity condition inside a vacuum tube released by a stratospheric balloon at an altitude of 40 km. The calibration of the capacitive transducers performed in laboratory has shown that it is possible to detect differential accelerations Δa (approximately-less-than) 1.4 × 10−10 m s−2.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 65 (1994), S. 1891-1893 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Picosecond optical pulses have been generated in different kinds of thresholdless dye microlaser operating in high-Q plane microcavities at high pumping rate. The temporal behavior of the system is studied by means of a simple rate equation analysis. It is shown that the buildup time of the output pulse is independent of the cavity finesse. The experiment has been performed by means of a temporally resolved up-conversion technique. A buildup time of the pulse of 3 ps, together with a rise time of 1.5 ps have been measured. These results correspond to a predictable response frequency of 300 GHz. © 1994 American Institue of Physics.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    International orthopaedics 23 (1999), S. 104-106 
    ISSN: 1432-5195
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé  Le but de cette étude est de déterminer prospectivement la densité osseuse préopératoire et de la comparer avec les résultats de la densité postopératoire après l’implantation d’une prothése de hanche controlaterale. La densité osseuse de 45 malades (x=54 années) a été mesurée avec la méthode DEXA à la hanche non operée, une semaine, 3 et 6 mois après l’implantation d’une prothese. Nos résultats montrent une réduction de la densité osseuse par l’immobilisation entre −3 et −5,9% (x=−3,9%). Cette différence diminue dans les prochains trois mois à une valeur de −2.5%, qui n’etait plus significative. L’évaluation préopérative montrait une différence de −4.5% en faveur de la hanche qui n’était pas atteinte (12 hanches).
    Notes: Abstract  It was the aim of this study to examine bone mineral density changes in the non-operated contralateral femur of patients undergoing total hip replacement. Bone density in the contralateral femur of 45 patients with an average age of 54 years was measured with the aid of the DEXA technique at one week, 3 and 6 months after total hip replacement. Within the first 3 months there was an average reduction of bone density of 3.9% (3.0%–5.9%). After a further 3 months the average difference was 2.5%.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    International orthopaedics 23 (1999), S. 310-311 
    ISSN: 1432-5195
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé  Après l’implantation d’une prothèse de genou une femme, agée de 67 ans, souffrait d’une douleur sur la partie laterale de genou, dans la région du menisque. L’arthroscopie montrait une partie du menisque postérieur, qui etait situé entre les deux composants de la prothese. Après la résection du menisque la douleur avait immédiament disparue. Ce cas souligne l’importance d’une résection exacte du menisque entier dans la technique opératoire d’une prothese de genou.
    Notes: Abstract  We report on a 67-year-old women who had pain after a knee arthroplasty in the region of the lateral meniscus. The arthroscopy showed the remainder of the posterior horn of the lateral meniscus, which luxated as a bucket handle tear into the joint. The resection led to an immediate relief. This case show the importance of meticulous removal of the entire menisci during bicondylar surface replacement.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1432-5195
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé. L’implantation d’une prothèse de la hanche a pour conséquence une diminution de la densité osseuse du fémur autour de la prothèse. Selon la littérature ce procéssus dépend surtout de la forme de la prothèse et de la durée de l’implantation. La densité osseuse de 27 malades a été mésurée avec la méthode DEXA en moyenne 21 mois après l’implantation d’une prothèse sur mesure de la hanche. Nos résultats montrent une réduction de la densité osseuse entre 5 (ROI 1) et 21% (ROI 7), surtout au calcar proximal. La réduction de la densité osseuse ne dépendait pas de la durée de l’implantation. En comparaison avec la littérature ces résultats, surtout la diminution très restreinte au ROI 7, sont en faveur d’une forme individuelle d’une prothèse de la hanche.
    Notes: Summary. Implantation of a total hip replacement leads to resorption of bone, especially in the upper femoral shaft and this depends mainly on the design of the stem, and also on the survival time of the implant. Density of the periprosthetic bone was examined with the DEXA method in both femurs in 27 patients at a mean of 21 months after implantation of uncemented custom-made femoral stems. A loss of bone density between 5% and 21% was found which was independent of the survival time of the implant. The maximum decrease was at the upper medial part of the calcar. The negligible loss of bone density, compared to other reports, favours the use of a computer tomography assisted custom-made femoral stem.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 0340-1855
    Keywords: Schlüsselwörter Präzision ; Variationskoeffizient ; DEXA ; Osteoporose ; Polyarthritis ; Key words Precision ; coefficient of variation ; DEXA ; osteoporosis ; rheumatoid arthritis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Precision of osteodensitometric measurements using dual energy X-ray absorptiometry (DEXA) depends on various known factors, such as positioning, aortic calcification or vertebral fractures. The purpose of this study was to investigate the influence of various diseases or bone density on the reproducibility of measurements in the lumbar spine and the proximal femur.  Measurements in the LWS p.a., LWS lat. and at Ward‘s triangle were made in a total of 100 patients. The subjects were repositioned between measurements. In order to be able to determine the influence of various diseases, four groups of 25 patients each were formed: three with the diagnosis osteoarthrosis, osteoporosis and rheumatoid arthritis and one control group. The mean percentual difference and coefficient of variation were calculated as the measure for reproducibility.  Mean percentual differences of 0.18 to 2.6% were found in the four groups at the three measurements sites. After calculation of coefficient of variation, a value between 1.2 and 2.7% was found for LWS p.a., between 7.1 and 15.7% for LWS lat. and between 4.1 and 9.9% at Ward‘s triangle. It was also conspicuous that the difference in coefficient of variation in osteoporosis patients was nearly double that in the control group in all measured areas. Conclusion: Lateral lumbar spinal measurements using DEXA cannot presently be recommended. LWS p.a. measurements and, with limitations, measurements at Ward‘s triangle have good precision and could be used for course documentation of bone density.
    Notes: Zusammenfassung Die Präzision osteodensitometrischer Messungen mit der dual energy X-ray absorptiometry (DEXA) hängt von verschiedenen bekannten Faktoren, wie Lagerung, Aortenverkalkung oder Wirbelkörperfrakturen ab. Ziel der Untersuchung war, den Einfluß verschiedener Erkrankungen bzw. der Knochendichte auf die Reproduzierbarkeit der Messungen an der Lendenwirbelsäule und am Femur zu überprüfen.  Insgesamt wurden 100 Patienten an der LWS p.a., LWS lat. und am Ward‘schen Dreieck doppelt gemessen, wobei zwischen den Messungen neu positioniert wurde. Um den Einfluß unterschiedlicher Erkrankungen festzustellen zu können, wurden zusätzlich 4 Gruppen à 25 Patienten mit den Diagnosen: Arthrose, Osteoporose und chronische Polyarthritis im Vergleich zur Kontrollgruppe gebildet. Als Maß für die Reproduzierbarkeit wurde jeweils die mittlere prozentuale Differenz und der Variationskoeffizient der beiden Messungen berechnet.  In den vier Gruppen ergaben sich an den drei Meßorten mittlere prozentuale Differenzen von 0,18 bis 2,6%. Nach Berechnung der Variationskoeffizienten fand sich für die LWS p.a. ein Wert zwischen 1,2 und 2,7% für die LWS lat. zwischen 7,1 und 15,7% und am Ward‘schen Dreieck zwischen 4,1 und 9,9%. Auffällig war zudem ein nahezu doppelt so hoher Variationskoeffizient der Patienten mit Osteoporose im Vergleich zur Kontrollgruppe an allen gemessenen Regionen. Ergebnis: Die laterale LWS-Messung beim DEXA-Verfahren ist derzeit nicht zu empfehlen. Die LWS p.a.-Messung und mit Einschränkung auch die Messung am Ward‘schen Dreieck können bei guter Präzision zur Verlaufsdokumentation der Knochendichte herangezogen werden.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 0340-1855
    Keywords: Schlüsselwörter Diclofenac ; in vitro ; Osteoblasten ; stromale Knochenmarkzellen ; Hüftprothektik ; Key words Diclofenac ; in-vitro ; osteoblasts ; bone marrow cells ; hip arthroplasty
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Introduction: Results of animal experiments have demonstrated that the osseous integration of non-cemented prostheses can, at the very least temporarily, be impaired by the application of non-steroidal antiphlogistic agents (such as diclofenac). It is the objective of this study to examine whether there is a direct influence of diclofenac used in usual clinical dosages (3 times 50 mg daily) on bone cells and their progenitor cells which would explain the observed slow integration of the prostheses. Methods: To investigate this, cultivated human in vitro osteoblasts and stromal bone marrow cells were incubated with increasing doses of the medications. Our study focused on the effect of diclofenac application on proliferation and functional metabolism in both cell lines. The measurable maximal plasma concentration 2h after the application of one tablet Voltaren 50® reached 1.6μg/ml. This correlated with diclofenac concentrations between 1 and 10 ml found in our experiments. The detected values were correlated to the control group (0 μg/ml diclofenac). Results: The drug effect upon osteoblasts was higher than on progenitor cells. The proliferation of in vitro stromal bone marrow cells, compared to untreated cells, was found to be decreased. We observed a decrease to 82% at a diclofenac concentration of 1 μg/ml, Osteoblasts exhibited a decrease to 97,5% at the same concentration. The DNA synthesis increased to 118% in stromal bone marrow cells, in osteoblasts to 144%. In contrast, we detected a neglectible decrease to 92% in the collagen synthesis of osteoblasts compared to untreated cells. The synthesis of osteocalcin by osteoblasts increased to 119%. The alkaline phosphatase activity was found to be decreased to 88% in stromal bone marrow cells and increased in osteoblasts to 111%. Conclusion: Temporary inhibiting effects on osseous integration in non-cemented prosthesis by diclofenac could be caused by a disturbance in the anabolic bone metabolism, exhibited by an increase of osteoblastic osteocalcin expression. Osteocalcin as a known negative regulator of the osteoneogenesis is most likely inhibiting the collagen matrix deposition.
    Notes: Zusammenfassung Einleitung: Nichtsteroidale Antiphlogistika (NSAR, z.B. Diclofenac) können das knöcherne Einwachsen nicht zementierter Prothesen zumindest vorübergehend beeinträchtigen. Es wird untersucht, ob ein direkter Einfluß von Diclofenac, in üblicher klinischer Dosierung (3×50 mg), bzw. der dadurch maximal erreichbaren Plasmakonzentration auf Knochenzellen und ihre Progenitoren besteht. Methoden: In-vitro kultivierte humane Osteoblasten und stromale Knochenmarkzellen wurden mit steigenden Medikamentendosierungen inkubiert und deren Wirkung auf das Proliferationsverhalten sowie Funktionsstoffwechsel gemessen. Die, durch Einnahme eines Dragees Voltaren 50®(Diclofenac) im Mittel nach 2 Stunden meßbare maximale Plasmakonzentration beträgt 1,6 μg/ml (26). Dies entspricht Diclofenackonzentrationen von etwa 1 μg/ml in unseren Experimenten. Die ermittelten Werte werden auf die Kontrollgruppe (0 μg/ml Diclofenac) bezogen. Ergebnisse: Die Wirkung von Diclofenac auf Osteoblasten ist bei allen Versuchen ausgeprägter als auf Vorläuferzellen. Die Proliferation stromaler Knochenmarkzellen wird bei Diclofenackonzentrationen von 1μg/ml auf 82%, bei Osteoblasten auf 97,5% reduziert. Die DNA-Synthese stromaler Knochenmarkzellen erhöht sich bei 1 μg/ml Diclofenac auf 118%, bei Osteoblasten auf 144%. Die Kollagensynthese der Osteoblasten wird auf 92% gesenkt. Die Osteocalcinsynthese der Osteoblasten steigt auf 119%. Die Aktivität der Alkalischen Phosphatase sinkt bei stromalen Knochenmarkzellen auf 88%, bei Osteoblasten steigt sie auf 111%. Schlußfolgerungen: Die zumindest während der Medikamentengabe verminderte Implantat-Knochen-Haftung könnte in einer Störung des anabolen Knochenstoffwechsels begründet sein, was sich in einer signifikanten Zunahme der spezifischen Osteocalcinexpression zeigt. Osteocalcin inhibiert als Negativ-Regulator der Osteogenese vermutlich die kollagene Matrixablage.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    European archives of oto-rhino-laryngology and head & neck 252 (1995), S. 159-162 
    ISSN: 1434-4726
    Keywords: Interleukin-6 ; Head and neck cancer ; Acute-phase response ; Fibrinogen ; C-reactive protein
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The acute-phase response is the answer of the organism to a disturbance of its homeostasis and is characterized by dramatic changes in the concentration of some plasma proteins defined as acute-phase proteins. In recent years several data have shown that interleukin-6 (IL-6) is the major inducer of acute-phase protein synthesis in human hepatocytes. Recently, we demonstrated higher IL-6 serum levels in head and neck cancer (HNC) patients than in healthy subjects. In the present study we examined the relationship between levels of IL-6 and of several acute-phase proteins, including C-reactive protein (CRP), α1-antitrypsin (AAT), αl-acid glycoprotein (AAG), haptoglobin (HPT) and fibrinogen. Eighteen patients were studied and had squamous cell carcinoma of the larynx (n = 9), oral cavity (n = 4), oropharynx (n = 3) and hypopharynx (n = 2). Proteins were measured at three time points before and three time points after surgery. Significant (P 〈 0.0001) relationships were found between IL-6 and CRP (r = 0.69), and fibrinogen (r = 0.51), whereas no correlation was found with AAT (r = 0.13, P = 0.56), AAG (r = 0.38; P = 0.07) and HPT (r = 0.16; P = 0.46). These data strongly suggest that IL-6 may play a key role in acute-phase protein synthesis in HNC and in regulation of the complex host response to malignancies.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 52 (1991), S. 117-121 
    ISSN: 1432-0649
    Keywords: 42.60D
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A colliding pulse mode-locked ring dye laser, pumped by an all-line small frame Ar+ laser has been used to generate stable pulses as short as 49 fs with pulse duration and stability similar to those obtained with the usual configuration where a single line of the pump is used. The effects of cavity alignment on the absorber saturation are presented and explained in terms of an analysis of stability of the ring cavity.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1432-0649
    Keywords: 42.60D
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We present a multipass femtosecond amplifier pumped by a Nd-YAG laser where the gain medium is given by a variable length dye cell. This system allows amplification factors up to 5 · 106 and output pulse energies of 150 μJ, while restricting the contribution of amplified spontaneous emission to 0.5% of the total output energy, without using any saturable absorber stage. A detailed study of the output pulsewidth as a function of the duration of the input chirped pulse is also presented.
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