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  • 1
    Electronic Resource
    Electronic Resource
    Electron mobility in tris(8-hydroxy-quinoline)aluminum thin films determined via transient electroluminescence from single- and multilayer organic light-emitting diodes (2001)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 89 (2001), S. 3711-3719 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Transient electroluminescence (EL) from single- and multilayer organic light-emitting diodes (OLEDs) was investigated by driving the devices with short, rectangular voltage pulses. The single-layer devices consist of indium-tin oxide (ITO)/tris(8-hydroxy-quinoline)aluminum (Alq3)/magnesium (Mg):silver (Ag), whereas the structure of the multilayer OLEDs are ITO/copper phthalocyanine (CuPc)/N,N′-di(naphthalene-1-yl)-N,N′-diphenyl-benzidine (NPB)/Alq3/Mg:Ag. Apparent model-dependent values of the electron mobility (μe) in Alq3 have been calculated from the onset of EL for both device structures upon invoking different internal electric field distributions. For the single-layer OLEDs, transient experiments with different dc bias voltages indicated that the EL delay time is determined by the accumulation of charge carriers inside the device rather than by transport of the latter. This interpretation is supported by the observation of delayed EL after the voltage pulse is turned off. In the multilayer OLED the EL onset—dependent on the electric field—is governed by accumulated charges (holes) at the internal organic-organic interface (NPB/Alq3) or is transport limited. Time-of-flight measurements on 150-nm-thin Alq3 layers yield weak field-dependent μe values of the order of 1×10−5 cm2/Vs at electrical fields between 3.9×105 and 1.3×106 V/cm. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1330766
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  • 2
    Electronic Resource
    Electronic Resource
    Efficient synthesis of 19-nor-9.beta.,10.alpha.-steroids (1972)
    s.l. : American Chemical Society
    The @journal of organic chemistry 37 (1972), S. 3183-3184 
    Details
    ISSN: 1520-6904
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/jo00985a032
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  • 3
    Electronic Resource
    Electronic Resource
    Low-temperature scanning laser microscopy of individual filaments extracted from (Bi, Pb)2Sr2Ca2Cu3O10+x tapes (2000)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 76 (2000), S. 2597-2599 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The method of low-temperature scanning laser microscopy is applied to visualize the resistive state in individual superconducting filaments extracted from (Bi, Pb)2Sr2Ca2Cu3O10+x/Ag tapes. This technique is capable of imaging the distributions of the critical currents over a sample. Using the nonbolometric response, a spatial resolution of about 1 μm is demonstrated for 10-μm-thick filaments. Some of the resistively visualized grain boundaries between crystallites show Josephson behavior. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.126420
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  • 4
    Electronic Resource
    Electronic Resource
    Variations of sperm release in three batches of zebrafish (2004)
    Oxford, UK; Malden , USA : Blackwell Science Ltd
    Journal of fish biology 64 (2004), S. 0 
    Details
    ISSN: 1095-8649
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: By collecting and counting the number of sperm released during separate matings in three batches of zebrafish Danio rerio, aged 3–4, 4–5 and 5–6 months, males were observed to release sperm before the female started laying their eggs. After the female left the nest, the number and motility of sperm and life span of sperm of younger fish were higher than those of older fish in water samples collected under the nest and at the surface of the tank. Sperm were released in the form of sperm trails laid on the nest surface, subsequently active spermatozoa left the trails and moved in the water for several minutes. Sperm trails consisted of bands of viscous material in which the sperm were embedded. In most cases eggs were not laid directly over the sperm trail, suggesting that sperm may contact the eggs after the latter are released into the water. In all the three tested groups there was no significant difference (P 〉 0·05) between the number of sperm collected on some portions of the acetate sheets which lined the nest ceiling. This result demonstrated that the greater activity of younger fish accelerated the sperm dispersal in water. Male sperm duct glands, seminal vesicles, known to secrete mucosubstances are probably involved in the production of sperm trails. The possible influence of insemination on the mating style of zebrafish is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.0022-1112.2004.00315.x
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  • 5
    Electronic Resource
    Electronic Resource
    Effects of low temperature irradiation with heavy ions on superconductor niobium (1974)
    Springer
    The European physical journal 268 (1974), S. 189-196 
    Details
    ISSN: 1434-601X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract To study the effects of heavy ion irradiation at low temperature on type II superconductor Nb, the transition temperatureT c , the normal state residual resistivityρ B , the transition widthΔT ph using oxygen ions of 25 MeV and subsequent thermal annealing were measured. The samples were held at temperatures 〈20 K during irradiation in a cryostat for in situ measurements. The maximum oxygen fluence was about 2·1015 cm−2 corresponding a relatively high defect concentration. The heavy ion irradiation experiments are described. The critical temperatureT c decreases with increasing residual resistivityρ B . In agreement with the theory and experiments, the gap anisotropy parameter is 〈a 2〉=0.008, subsequent annealing shows a hysteresis ofT c versusρ B . The resistivity saturation value ΔρBS = 2.55 μΩ cm was obtained and different recovery stages were found. Significant broadening of transition width during irradiation was observed.T c andΔT ph anneal to 60% in the temperature interval of (60–90) K. Oxygen induced effects as a simulation method of high neutron damage are compared with irradiation measurements using neutrons and deuterons.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01669879
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  • 6
    Electronic Resource
    Electronic Resource
    Ein neues resorbierbares Knochen-Knorpel-Ersatztransplantat (2000)
    Springer
    Der Orthopäde 29 (2000), S. 151-157 
    Details
    ISSN: 1433-0431
    Keywords: Schlüsselwörter Bioimplantat • Biomechanik •¶Knorpeldefekt • Knorpelregeneration •¶Mesenchymale Zelldifferenzierung ; Key words Bioimplant • Biomechanics • Cartilage ¶defect • Cartilage repair • Mesenchymal cell differentiation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Hyaline cartilage is thought to be unable to regenerate. All efforts so far – including autologous chondrocyte cell transplantation – to reconstruct cartilage defects in joints have not been totally convincing. However, mesenchymal cells are able to differentiate into chondrocytes under mechanical pressure conditions. In this study, an open porous resorbable two-layer “bioimplant” was constructed in which mechanical pressure was exerted onto mesenchymal cells when migrated into the open porous structure of the bioimplant. Differentiation of the cells into chondrocytes was thus induced. The bioimplants were implanted into the medial condyles of nine rabbits and left in place for eight or twelve weeks, respectively. In seven of these cases, cartilage formation was found, in contrary to the controls in which only connective tissue and bone had grown into the empty holes. The new bioimplants have proven their effectiveness in cartilage defect repair and might evolve in the future as a new alternative treatment of full thickness defects of joint surfaces.
    Notes: Zusammenfassung Gelenkknorpel gilt in der Regel als nicht regenerationsfähig. Bis jetzt durchgeführte Versuche zur Wiederherstellung des Gelenkknorpels, inklusive der Knorpelzelltransplantation, zeigten wenig erfolgversprechende Ergebnisse. Jedoch gibt es Hinweise, dass unter Druckbelastung mesenchymale Stammzellen sich in Knorpelzellen differenzieren können. In der vorliegenden Studie wurde ein offenporiges resorbierbares, zweischichtiges „Bioimplantat“ konstruiert, das nach Implantation in einen Knochen-Knorpel-Defekt die physiologischen Druckverhältnisse nachahmt und so eine Differenzierung von mesenchymalen Stammzellen zu hyalinem Knorpel ermöglicht. An 9 Kaninchen wurde dieses Bioimplantat an Knochenknorpeldefekten des Femurkondylus über 2 verschiedene Zeiträume erprobt und mit Leerlochversuchen verglichen. Durch die Bioimplantate gelang es im Gegensatz zu den Leerlochversuchen in 7 von 9 Fällen Bereiche mit hyalinartigem Knorpel zu induzieren. Die Methode scheint einen neuen erfolgsversprechenden Ansatz zur Reparation von Knorpeldefekten darzustellen.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/PL00003710
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  • 7
    Electronic Resource
    Electronic Resource
    Faziale Dysmorphien und Dysostosis multiplex bei einem Säugling (2000)
    Springer
    Monatsschrift Kinderheilkunde 148 (2000), S. 494-495 
    Details
    ISSN: 1433-0474
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001120050585
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  • 8
    Electronic Resource
    Electronic Resource
    Bullöse Hautveränderungen bei einem Neugeborenen (2000)
    Springer
    Monatsschrift Kinderheilkunde 148 (2000), S. 154-155 
    Details
    ISSN: 1433-0474
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001120050029
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  • 9
    Electronic Resource
    Electronic Resource
    Dunkelgrüne Milchzähne (2000)
    Springer
    Monatsschrift Kinderheilkunde 148 (2000), S. 1102-1103 
    Details
    ISSN: 1433-0474
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001120050704
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  • 10
    Electronic Resource
    Electronic Resource
    Synthese von Thiomorpholin und 2-monoalkylierten Thiomorpholinen via 5,6-Dihydro-1,4-thiazine (1970)
    Springer
    Monatshefte für Chemie 101 (1970), S. 1295-1308 
    Details
    ISSN: 1434-4475
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Abstract Propionaldehyde, n-butyraldehyde and n-valeraldehyde react with ethylenimine in the presence of dimethylformamide or anhydrous K2CO3 to mixtures of 2-monoalkylated 5.6-dihydro-4H-1.4-thiazines (2–4) and 2-monoalkylated thiazolidines (6–8). When acetaldehyde is inserted in this reaction, solely 2-methyl-thiazolidine (5) could be isolated. By condensation of α-chloroaldehydes with the sodium salt of cysteamine 2-alkyl-5.6-dihydro-4H-1.4-thiazines (2,3) are obtained as the only reaction products. Reaction of2 and3 with formic acid affords mixtures of N-formylthiomorpholines (9, 11) and N-formyl-5.6-dihydro-1.4-thiazines (10, 12), which yield either by hydrolysis with dilute HCl (9, 11→13, 14) or better by hydrogenation and hydrolysis with NaBH4 (9, 11, 10, and12→13, 14) the corresponding thiomorpholines. Unsubstituted thiomorpholine (15) as well as13 and14 are obtained in better yields (42–70%), if the 5.6-dihydro-1.4-thiazines, synthesized by reaction of α-chloroaldehydes with the cysteamine-sodium salt, are not isolated, but directly hydrogenated with NaBH4.
    Notes: Zusammenfassung Propionaldehyd, n-Butyraldehyd und n-Valeraldehyd reagieren mit Äthylenimin und Schwefel in Gegenwart von Dimethylformamid oder wasserfr. K2CO3 zu Gemischen von 2-monoalkylierten 5,6-Dihydro-4H-1,4-thiazinen (2–4) und 2-monoalkylierten Thiazolidinen (6–8). Bei Einsatz von Acetaldehyd in diese Reaktion konnte nur 2-Methylthiazolidin (5) isoliert werden. Durch Kondensation von α-Chloraldehyden mit Cysteaminnatrium erhält man die 2-Alkyl-5,6-dihydro-4H-1,4-thiazine (2,3) als alleinige Reaktionsprodukte. Die Umsetzung von2 und3 mit Ameisensäure führt zu Gemischen von N-Formylthiomorpholinen (9, 11) und N-Formyl-5,6-dihydro-1,4-thiazinen (10, 12), aus denen man entweder durch Hydrolyse mit verd. HCl (9,11→13,14) oder besser durch Hydrierung und Hydrolyse mit Natriumboranat (9,11,10 und12→13,14) die entsprechenden 2-monoalkylierten Thiomorpholine gewinnt. Unsubstituiertes Thiomorpholin (15) sowie13 und14 lassen sich in besseren Ausbeuten (42–70%) gewinnen, wenn man die durch Umsetzung der α-Chloraldehyde mit Cysteaminnatrium erhaltenen 5,6-Dihydro-1,4-thiazine nicht isoliert, sondern direkt mit Natriumboranat behandelt.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00911395
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