Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    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
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    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
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    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
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Influence of bile acids and free fatty acids on physicochemical properties of LP-X (1978)
    Springer
    Research in experimental medicine 172 (1978), S. 211-221 
    Details
    ISSN: 1433-8580
    Keywords: Physicochemical properties of LP-X ; Effects of bile salts ; Free fatty acids and postheparin lipolytic activity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In this study it is demonstrated, that incubation of both, bile acids and free fatty acids with LP-X, the abnormal plasmalipoprotein found in patients suffering from cholestasis or LCAT-deficiency, results in striking alterations of the physico-chemical and immunological properties of LP-X: 1. The cathodic mobility in agar is changed into an anodic migration of the material. 2. The unique appearance of LP-X on electronmicrographs is altered by the incubation revealing fingerprint like structures. 3. The albumin portion of LP-X becomes immunologically detectable. 4. Bile salts cause marked changes in the hydrated density of the material as determined by zonal ultracentrifugation. 5. In vitro incubation of LP-X with postheparin plasma causes a complete disappearance of LP-X as judged by its typical migration on agar electrophoresis. All these alterations can be prevented or reversed by the addition of albumin in appropriate concentrations. These findings are important in the light of studies designed to investigate the catabolic action of plasma lipolytic enzymes on LP-X, as well as for follow up studies of LP-X concentrations during the course of disease.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01855831
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Parameter- und Kombinationsresonanzen bei Rotorsystemen mit Unsymmetrien (1979)
    Springer
    Archive of applied mechanics 48 (1979), S. 65-72 
    Details
    ISSN: 1432-0681
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Summary The theory of parameter and combination resonances is applied to rotor systems having asymmetric elements. The number of formal possible resonances of first order is usually given by f 2, when f is the number of degrees of freedom. The number of resonances can be essentially reduced representing the rotor system by inertial as well as by rotating coordinates. Resonance frequencies must appear in both representations. By this, for a rotor system having asymmetric shaft stiffness and asymmetric bearings, the number of possible resonances is reduced to f 2/4. While parameter resonances only arise in the case of critical speeds of forward precession, combination resonances may only appear summing critical frequencies of a forward and of a backward precession.
    Notes: Übersicht Für Rotorsysteme mit Unsymmetrien wird die Theorie der Parameter- und Kombinationsresonanzen angewandt, um die kritischen Frequenzen der Parametererregung festzustellen. Die Anzahl der formal möglichen Resonanzfrequenzen 1. Ordnung, die bei einem Rotorsystem mit f Freiheitsgraden bei üblicher Untersuchungsweise f 2 beträgt, wird wesentlich reduziert, indem die mathematische Beschreibung sowohl im inertialen als auch im mitdrehenden Koordinatensystem erfolgt. Nur die in beiden Darstellungen gleichen Resonanzfrequenzen sind interessant. Für ein Rotorsystem mit Wellen- und Lagerunsymmetrien ergeben sich Parameterresonanzen nur für Gleichlauf-Frequenzen; die Kombinationsresonanzen treten nur in Summenform zwischen je einer Gleichlauf- und einer Gegenlauf-Frequenz auf. Die Anzahl der möglichen Instabilitäten hat sich auf f 2/4 verringert.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00539904
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Schnelligkeitsoptimales Ausrichten von Trägheitsplattformen (1971)
    Springer
    Archive of applied mechanics 40 (1971), S. 248-265 
    Details
    ISSN: 1432-0681
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Summary Time-optimal self-alignment methods for inertial platforms are investigated. A mathematical model of the alignment mechanism is derived by the basic operation modes of stable platforms and of their alignment. The control torques of this system are time-optimally determined by Neustadt's iteration technique based on the maximum principle of Pontrjagin. Because of the considerable amount of computational work a suboptimal bang-bang control of the misalignment angles is proposed. The increase of alignment time is estimated and compared to the optimal time. It turns out to be small. The desired closed loop control for alignment is constructed by means of a minimal observer. The proposed control loop yields an essentially reduced alignment time which is about the twentieth part of the times for present platforms without loss of steady-state alignment accuracy.
    Notes: Übersicht Das selbsttätige Ausrichten von Trägheitsplattformen dauert mit den herkömmlichen Verfahren ungefähr 10 Minuten. Da andererseits die Plattformträger wie Schiffe, Flugzeuge oder Raketen oft schon innerhalb weniger Minuten startklar sein müssen, besteht an einer Verringerung der Einstellzeit großes Interesse. Es werden daher die Möglichkeiten einer zeitoptimalen Regelung des Ausrichtvorgangs untersucht. An Hand der grundsätzlichen Funktionsweise einer Trägheitsplattform und ihres Ausrichtregelkreises wird ein mathematisches Modell für den Ausrichtvorgang hergeleitet. Die in diesem System auftretenden Steuermomente werden nach dem Maximumprinzip von Pontrjagin mit Hilfe des Neustadtschen Iterationsverfahrens zeitoptimal bestimmt. Infolge des hierbei erforderlichen, großen Rechenaufwands wird jedoch zu einer suboptimalen Zweipunktsteuerung der Plattformfehlwinkel übergegangen. Die dadurch bedingte, geringfügige Verlängerung der Einstellzeit wird gegenüber der Optimalzeit abgeschätzt. Den gesuchten, zeitsuboptimalen Ausrichtregelkreis erhält man schließlich, indem man das Syntheseproblem mit Hilfe eines Minimalbeobachters löst. Das vorgeschlagene Regelsystem bewirkt eine beträchtliche Verkürzung der Einstellzeit bis zu einem zwanzigstel der bisher üblichen Zeiten, ohne daß dabei eine Verschlechterung der statischen Ausrichtgenauigkeit auftritt.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00532196
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Kreiselverhalten eines elastisch gelagerten Rotors (1972)
    Springer
    Archive of applied mechanics 41 (1972), S. 110-140 
    Details
    ISSN: 1432-0681
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Summary High-speed rotors are of increasing technical interest. Their motion is influenced by gyroscopic forces and by the elasticity and damping of their suspension. Starting with the equations of motion the rotor's natural behaviour and disturbance behaviour is investigated. Running through the critical speeds instationary motions appear. Axial forces are leading to parametric excited vibrations. Optimal parameters of a rotor are determined. Experiments verify the validity of the theoretical results.
    Notes: Übersicht Schnelle'Rotoren besitzen eine große technische Bedeutung. Ihr Bewegungsverhalten wird durch die Kreiselkräfte und die Elastizität und Dämpfung der Lagerung beeinflußt. Ausgehend von den Bewegungs-gleichungen wird das Eigenverhalten und das Störverhalten eines Rotors untersucht. Das Durchfahren der kritischen Drehzahlen ergibt instationäre Bewegungen, während axiale Erregerkräfte auf parametererregte Schwingungen führen. Die optimalen Parameter eines Rotors werden bestimmt. Experimentelle Untersuchungen bestätigen die Gültigkeit der theoretischen Ergebnisse.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00533586
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    In vitro inactivation of corpora allata of the bugOncopeltus fasciatus by precocene II (1979)
    Springer
    Cellular and molecular life sciences 35 (1979), S. 704-705 
    Details
    ISSN: 1420-9071
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Corpora allata fromOncopeltus fasciatus incubated in vitro in medium containing 10−5.35 M (1 μg/ml) of precocene II lose their ability to secrete juvenile hormone when reimplanted into last instar larvae.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01960409
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Biochemical characteristics of Ehlers-Danlos syndrome type VI in a family with one affected infant (1979)
    Springer
    Human genetics 〈Berlin〉 46 (1979), S. 41-49 
    Details
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The parents of a child with the clinical symptoms of Ehlers-Danlos syndrome type VI were identified as third-degree cousins. Biochemical analysis of the dermis of the patient revealed a complete lack of hydroxylysine in the dermal collagen. The dermis of both parents contained only half the amount of hydroxylysine found in healthy individuals. Hydroxylation of prolyl residues was normal in the skin of the patient and his parents. Investigation of the collagen synthesized by fibroblasts derived from the skin of the patient showed a normal proportion of type I and type III collagen. However, while hydroxylation of prolyl residues was normal in type I and type III collagen, hydroxylation of lysyl residues was markedly lower than normal in both type I and type III collagen.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00278900
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Renal test dyes IV (1976)
    Springer
    Pflügers Archiv 364 (1976), S. 83-89 
    Details
    ISSN: 1432-2013
    Keywords: Fluorescence microphotometry ; Renal test dyes ; Sulfonefluorescein ; Renal secretion ; Probenecid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The present study describes for the first time the use of the fluorescent dye sulfonefluorescein for intravital microscopy and microphotometry on the renal surface of rats. With help of this dye tubular secretion can be observed in mammalian kidney in vivo. Tubular secretion can further be quantified with microphotometrical measurements. The molecular structure of sulfonefluorescein is closely related to phenol red, which is known for its tubular secretion. Clearance experiments also show a secretion of sulfonefluorescein. The secretion can be inhibited by probenecid. Ureter ligation causes a strong increase in tubular concentration of the dye. After a temporary ischemia dye accumulation in tubular lumen is greatly reduced.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01062916
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...