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  • 1
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 104 (1996), S. 4198-4203 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The deuterated dicyanoquinonediimine salt Cu(2-CD3,5-CD3-DCNQI)2, (d6), a highly conductive organic metal, exhibits a phase transition from the metallic to the insulating state at Tc≈60 K. In a wide temperature range we observe an anticoincidence of high conductivity and electron spin resonance (ESR). These experiments were performed simultaneously in our ESR apparatus equipped for application of He pressure up to 200 bar. Near Tc there is a coexistence of conducting (ESR-silent) and insulating (ESR-detectable) domains. This correlation of ESR and conductivity σ points to a percolation limited conductivity. Upper and lower limits of the size of the domains are given. Light shifts Tc to lower temperatures, pressure to higher ones. This could be due to shrinking of the lattice which induces the phase transition when critical structural parameters are approached. This is most probably explained by a simultaneous development of a charge density wave (CDW) and a spin pairing within the DCNQI stack together with the trimerization of the lattice. Systematic measurements by variation of temperature, pressure, and light led to phase diagrams of (d6) and to the understanding of the mechanism of the phase transitions. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    The journal of membrane biology 145 (1995), S. 233-244 
    ISSN: 1432-1424
    Keywords: Ca2+ current ; Arachidonic acid ; Myristic acid ; Tetradecyltrimethylammonium ; Sphingosine ; Neuroblastoma x glioma hybrid cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Low-voltage-activated (1-v-a) and high-voltage-activated (h-v-a) Ca2+ currents I Ca were recorded in whole-cell voltage clamped NG108-15 neuroblastoma x glioma hybrid cells. We studied the effects of arachidonic acid (AA), oleic acid, myristic acid and of the positively charged compounds tetradecyltrimethyl-ammonium (C14TMA) and sphingosine. At pulse potentials 〉−20 mV, AA (25-100 μm) decreased 1-v-a and h-v-a I Ca equally. The decrease developed slowly and became continually stronger with increasing time of application. It was accompanied by a small negative shift and a slight flattening of the activation and inactivation curves of the 1-v-a I Ca. The shift of the activation curve manifested itself in a small increase of 1-v-a I Ca at pulse potentials 〈−30 mV. The effects were only partly reversible. The AA effect was not prevented by 50 μm 5, 8, 11, 14-eicosatetraynoic acid, an inhibitor of the AA metabolism, and not mimicked by 0.1–1 μm phorbol 12, 13-dibutyrate, an activator of protein kinase C. Probably, AA directly affects the channel protein or its lipid environment. Oleic and myristic acid acted similarly to AA but were much less effective. The positively charged compounds C14TMA and sphingosine had a different effect: They shifted the activation curve of 1-v-a I Ca in the positive direction and suppressed 1-v-a more than h-v-a I Ca; their effect reached a steady-state within 5–10 min and was readily reversible. C14TMA blocked 1-v-a I Ca with an IC50 of 4.2 μm while sphingosine was less potent.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Journal of molecular medicine 40 (1962), S. 921-928 
    ISSN: 1432-1440
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Journal of molecular medicine 40 (1962), S. 1175-1180 
    ISSN: 1432-1440
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1432-0533
    Keywords: Thromboangiitis obliterans ; Dementia ; Cortical synaptophysin expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The generalized form of von Winiwarter-Buerger's disease (WBD) occasionally involves the brain. However, pure cerebral forms of the disease were also described by Spatz and Lindenberg (“Spatz-Lindenberg's disease”, SLD). Both, the type I, which involves the large basal arteries, and the type II, which results in a sickle-shaped granular atrophy of the cerebral cortex, are often accompanied by (“vascular”) dementia, which Lindenberg and Spatz mainly attributed to the bilateral involvement of the second frontal gyrus by granular atrophy. Recently, synaptic deprivation of the cortical gray matter has been shown to occur in the dementia of Alzheimer type (DAT) and other neurodegenerative disorders. In DAT, the synaptic loss highly correlated with the degree of the mental impairment. We wanted to examine whether similar changes also occurred in dementia of vascular origin, for which SLD, although infrequent, is a typical example. In fact, we found that in three cases of typical SLD type II the synaptophysin immunoreactivity of the cortical neuropil in areas without overt infarcts or scar formation was as much reduced as in Alzheimer's disease. Although it must be taken into account that in the present cases the synapse loss might, at least in part, be due to secondary (Wallerian) degeneration as a result of the neuronal loss in the “watershed” regions of the arterial blood supply, it cannot be excluded that a decline of cortical synaptic contacts in areas without necroses or scars may occur as a primary event, contributing to the pathogenesis of the dementia. Final conclusions can only be expected from investigations into further cases of cerebro-vascular disorders with and without dementia.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1432-055X
    Keywords: Schlüsselwörter TIVA ; Propofol/Remifentanil ; Balancierte Anästhesie ; Sevofluran/Fentanyl ; Laparoskopie ; Gynäkologie ; Key words TIVA ; Propofol/Remifentanil ; Balanced anaesthesia ; Sevoflurane/Fentanyl ; Laparoskopy ; Gynaecology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Abstract Objective: This study was designed to investigate the differences between TIVA with propofol/remifentanil (P/R) and balanced anaesthesia with sevoflurane/fentanyl (S/F) in gynaecological laparoscopic surgery. Emphasis was put on haemodynamic reaction, recovery profile, postoperative side effects and patient satisfaction. Methods: Sixty patients were randomly assigned to receive either total intravenous anaesthesia with propofol/remifentanil or anaesthesia with sevoflurane/fentanyl. After premedication (midazolam) and induction of anesthesia (propofol, atracurium) in both groups, either 1 µg/kg fentanyl (S/F) or 1 µg/kg remifentanil (P/R) was injected. Anaesthesia was maintained with 0.5 µg/kg/min remifentanil (reduced to 50% after 5 min) and 0.06 µg/kg/min propofol (P/R) or 1.7 vol % sevoflurane (S/F). Both groups were mechanically ventilated with 30% oxygen in air. The administration of sevoflurane and the infusion of the anaesthetics were adjusted to maintain a surgical depth of anaesthesia. For postoperative analgesia 1 g paracetamol was administered rectally prior to surgery. After recovery 20 mg/kg metamizol was given intravenously. At the end of surgery the anaesthetics were discontinued and haemodynamics, early emergence from anaesthesia, pain level, frequency of analgesic demand, incidence of PONV, shivering and patient satisfaction were assessed. Parameters were recorded for 24 h postoperatively. Results: Recovery time after propofol-remifentanil anaesthesia was significantly shorter than after administration of sevoflurane and fentanyl (spontaneous ventilation 4.1 vs. 6.3 min, extubation 4.3 vs. 9.3 min, eye opening 4.4 vs 8.2 min, stating name 5.3 vs. 13.2 min, stating date of birth 5.4 vs. 13.3 min). There were no significant differences between the groups in shivering, pain score, analgesic demand and PONV. The S/F group responded to tracheal intubation with significantly higher blood pressure than the P/R group. During maintenance of anaesthesia heart rate in patients with S/F was significantly higher (P/R: HR max +16/–10; S/F: HR max +24/–0.). Measured on a scale from very satisfied to very dissatisfied, 73% of the patients in the P/R group were ”very satisfied” (S/F 23%) and 23% were ”satisfied” (S/F 62%). Conclusion: Compared with patients given balanced anaesthesia with sevoflurane and fentanyl, TIVA with propofol and remifentanil proved to be particularly suited for gynaecological laparoscopic surgery. Its major advantages are haemodynamic stability, significantly shorter times of emergence, and the exceptional acceptance by the patients.
    Notes: Zusammenfassung Fragestellung: Unterscheidet sich eine TIVA mit Remifentanil/Propofol (P/R) von einer balancierten Anästhesie mit Sevofluran/Fentanyl (S/F) hinsichtlich der Hämodynamik, des Aufwachverhaltens, postoperativer Nebenwirkungen und der Patientenzufriedenheit? Methodik: 60 Patientinnen wurden randomisiert einer Anästhesie mit (P/R) oder (S/F) zugeteilt. Nach oraler Prämedikation mit Midazolam wurde die Narkose mit Propofol eingeleitet, die Relaxierung erfolgte mit Atracurium. Gemäß randomisierter Gruppenzuteilung wurde 1 µg/kg Fentanyl oder 1 µg/kg Remifentanil i.v. injiziert und die Narkose bis zum OP-Ende entweder mit 0,5 µg/kg/h Remifentanil (Reduktion auf 50% nach 5 min) und mit 0,06 mg/kg/min Propofol oder mit 1,7 Vol.-% Sevofluran aufrechterhalten. Beide Gruppen wurden mit 30% O2 in Luft beatmet. Die Dosierung von Sevofluran, Propofol und Remifentanil wurden bei Bedarf der jeweiligen Intensität chirurgischer Stimuli angepaßt. Zur postoperativen Analgesie erhielten alle Patientinnen zu OP-Beginn 1 g Paracetamol rektal, nach Erwachen Metamizol 20 mg/kg i.v.. Bei OP-Ende wurde die Anästhetikazufuhr unterbrochen und folgende Parameter erfaßt: mittlerer arterieller Blutdruck, Herzfrequenz, Aufwachverhalten, Schmerzintensität, Analgetikabedarf, PONV, Muskelzittern und die Patientenzufriedenheit mit dem Anästhesieverfahren. Der Beobachtungszeitraum betrug 24 h. Ergebnisse: Die Patientinnen waren nach einer P/R Narkose signifikant eher wach und orientiert als nach einer Anästhesie mit S/F (Spontanatmung 4,1 vs. 6,3 min, Extubation 4,3 vs. 9,3 min, Augenöffnen 4,4 vs. 8,2 min, Namen nennen 5,3 vs. 13,2 min, Geburtsdatum 5,4 vs. 13,3 min). Die Inzidenz von PONV (43% vs. 43%) und Muskelzittern (56% vs. 37%) sowie die Schmerzintensität und die Anzahl der Schmerzmittelanforderungen (67 vs. 52) waren in beiden Gruppen vergleichbar. Der MAP war in der S/F-Gruppe nach der Intubation signifikant höher, die HF im gesamten Verlauf signifikant höher als in der P/R Gruppe (P/R: HF max. +16/–10; S/F: HF max. +24/–0). Auf einer Skala von „sehr zufrieden–sehr unzufrieden” waren 73% (P/R) der Patientinnen mit dem Anästhesieverfahren „sehr zufrieden” (S/F 23%), 23% „zufrieden” (S/F 62%). Schlußfolgerung: Verglichen mit einer balancierten Anästhesie mit Sevofluran und Fentanyl erwies sich die TIVA mit Remifentanil und Propofol als besonders vorteilhaft für laparoskopische Operationen in der Gynäkologie. Wesentliche Vorteile waren signifikant schnellere Aufwachzeiten, die hämodynamische Stabilität und die große Akzeptanz des Anästhesieverfahrens durch die Patientinnen.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 52 (1991), S. 223-233 
    ISSN: 1432-0630
    Keywords: 44.25 ; 44.60+f ; 47.25.Q
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract The temperature oscillation accompanying the photoacoustic effect generates a periodic variation of the vapor pressure of a liquid. The propagation of the oscillating concentration of the vapor in the inert cell gas (air) is described by a mass diffusion wave on which a convective motion of the gas is superposed. The diffusion wave characterized by the diffusion coefficient of the cell gas alone can be measured by the Mirage effect, whereas a microphone detects the total mass flux including the convective flux, which increases with temperature. On approaching the boiling temperature, the convective flow will govern the oscillating transport of mass. The photoacoustic signal is determined directly from the flux of heat and mass at the boundary between liquid and gas using the Gauss' divergence theorem. We have found that the temperature behaviour of the amplitude and phase angle of the photoacoustic signal depends on the length of the gas column in the cell. The contribution of thermal expansion to the photoacoustic signal is considered using the composite piston model. The results of the calculations agree fairly well with the experimental data.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    European spine journal 3 (1994), S. 91-97 
    ISSN: 1432-0932
    Keywords: Biomechanics ; Spine tester ; Spinal stability ; Muscle simulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We report a new apparatus to determine the quasistatic, three-dimensional, load-displacement characteristics of spines including muscle forces. The loading frame can be adapted to mono- and polysegmental specimens from the lumbar or cervical spine as well as to entire spines. Three force and three moment components can be applied in either direction individually or in combination with no constraint on the resulting motion; the loads can be applied at user-chosen rates of application and release with continuous recording of displacements, so as to study either creep or relaxation. The loads and displacement-measuring devices are computer-controlled. Thus, this testing device provides a tool for many kinds of stability tests and for basic research of spine biomechanics. A first experiment shows that the application of muscle forces significantly affects the load-deformation characteristics and intradiscal pressure.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    European journal of pediatrics 155 (1996), S. 74-76 
    ISSN: 1432-1076
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    European journal of pediatrics 152 (1993), S. 462-466 
    ISSN: 1432-1076
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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