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
    .pi.-Equivalent heterocyclic congeners of tropone. Azatropones (1972)
    s.l. : American Chemical Society
    The @journal of organic chemistry 37 (1972), S. 208-215 
    Details
    ISSN: 1520-6904
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/jo00967a008
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    A new composite made of polyurethane and glass ceramic in a loaded implant model: a biomechanical and histological analysis (1997)
    Springer
    Journal of materials science 8 (1997), S. 753-756 
    Details
    ISSN: 1573-4838
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Technology
    Notes: Abstract The biocompatibility and osseous integration of a new composite material made of polyurethane and a calcium silicophosphate ceramic was investigated in a loaded implant model in sheep and compared to that of commercially pure titanium. Six months after implantation, interfacial shear strength was higher between the titanium and bone than between the composite and bone. After 2 years, however, the shear strength was significantly higher in the composite group. Histologically, both implants were surrounded by bone and fibrous tissue and there were no signs of inflammation. Direct contact of bone on the composite surface increased significantly with time, whereas there was no time-dependent increase of bone contact on titanium. It can be concluded that the biocompatibility and osseous integration of the composite was very good in the loaded implant model used. It is therefore suggested that the new composite is a promising biomaterial for orthopaedic implants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018508511787
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Acutely repaired proximal anterior cruciate ligament ruptures in sheep – by augmentation improved stability and reduction of cartilage damage (1997)
    Springer
    Journal of materials science 8 (1997), S. 855-859 
    Details
    ISSN: 1573-4838
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Technology
    Notes: Abstract The aim of this study was to evaluate the healing capacity of proximal anterior cruciate ligament (ACL) ruptures following primary repair with and without a bioresorbable augmentation. The ACL was transected at the femoral origin in the right knee joint of 24 sheep. The ACL was repaired in eight sheep (group B) without, and in eight sheep (group C) with a bioresorbable augmentation. Eight sheep without repair served as a control (group A). No immobilization was performed in any group. The sheep were sacrificed 13 weeks post-operatively. Macroscopically, all repaired ACLs were healed. The augmentation device was broken in all cases, but not completely degraded. In group A, none of the transected ACLs had healed. The anterior drawer under a load of 50 N was significantly lower in group C than in group A (p〈0.01). No significant difference was seen between groups B and A. The distribution and extent of chondromalacia (CM) in the operated knees depended on the type of operative treatment (p〈0.01). Groups A and B showed significantly more CM in the operated knee than in the non-operated knee (each p〈0.05). Proximal ACL ruptures can heal in sheep after both non-augmented and augmented ACL repair with free-functional rehabilitation. However, augmented repair leads to significantly better stability of the knee joint compared to transected controls and better limits the development of degenerative changes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018597604034
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Über antibakterielle Hemmungsstoffe (Inhibine) im schleimigen Nasensekret (1936)
    Springer
    Medical microbiology and immunology 118 (1936), S. 445-454 
    Details
    ISSN: 1432-1831
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Zusammenfassung 1. Es gelang im normalen schleimigen Nasensekret antibakterielle Hemmungsstoffe (Inhibine) gegenüber den von mir untersuchten Bakterien (Bac. subtilis, Bac. anthracis und Bac. diphtheriae) nachzuweisen, während solche Hemmungsstoffe im wässerigen Sekret eines akuten Schnupfens nicht gefunden wurden. 2. Diese Inhibine richten ihre hemmende Kraft sowohl gegen das unbeschränkte Wachstum der Nasensekret-Eigenkeime als auch gegen das Wachstum künstlich von außen zugeführter Bakterien. 3. Die Eigenschaften dieser antibakteriellen Hemmungsstoffe (Inhibine) des schleimigen Nasensekretes wurden — soweit die technischen Schwierigkeiten eine Nachprüfung ermöglichten —mit den Eigenschaften der Inhibine des menschlichen Speichels übereinstimmend befunden, d h. sie erwiesen sich als thermolabil und lagerempfindlich, aber als nicht empfindlich gegen Kälte und — im Gegensatz zu den LysozymenFlemings — als durch den Nähragar nicht diffundibel.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02177848
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Biodegradable bone cements (1997)
    Springer
    Der Orthopäde 26 (1997), S. 459-462 
    Details
    ISSN: 1433-0431
    Keywords: Key words Fracture healing • Bone cement • Degradation ; Schlüsselwörter Frakturheilung • Knochenzement • Resorption
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung In der Knochenbruchbehandlung werden Knochenzemente bei der Rekonstruktion von Kompressionsfrakturen, zur Auffüllung von Knochendefekten und für die Verbesserung der Verankerung von Implantaten im osteoporotischen Knochen eingesetzt. Da die Knochenzemente dabei nur eine temporäre Funktion haben, wären Zemente wünschenswert, die nach Abschluß der Knochenheilung abgebaut werden. Prinzipiell wird diese Anforderung von Kalziumphosphatzementen erfüllt, die durch verschiedene Forschergruppen in den letzten Jahren neu entwickelt wurden und in ihrem chemischen Aufbau dem Apatit im Knochen sehr ähnlich sind. Die Verarbeitungsbedingungen, die erreichten mechanischen Festigkeiten und die beobachteten Resorptionszeiten weisen zwischen den verschiedenen Produkten erhebliche Unterschiede auf. Klinische Langzeitstudien liegen bisher noch nicht vor. Ob diese neue Gruppe von Knochenzementen alle in sie gesetzten Erwartungen erfüllen kann, muß deshalb die Zukunft zeigen.
    Notes: Summary Bone cements are used to treat compression fractures, fill bone defects and improve implant fixation in osteoporotic patients through reinforcement of weak bone. When the fracture repair is complete the bone cement ideally should degrade. In general, calcium-phosphate bone cements are biodegradable and can fulfill this temporary function. Several research groups have developed calcium-phosphate bone cements in the last years which have a chemical structure similar to that of the apatite of bone. However the conditions for processing the cement intraoperatively, as well as the mechanical properties and degradation characteristic of the various products show great variations. Clinical long-term studies have not yet been reported so far. Whether these new types of bone cements fulfill all the requirements for clinical application is still not certain and remains to be determined in future studies.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/PL00003400
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    In-vitro-Zellverhalten humaner Osteoblasten nach physiologischen dynamischen Dehnungen (2000)
    Springer
    Der Orthopäde 29 (2000), S. 85-90 
    Details
    ISSN: 1433-0431
    Keywords: Schlüsselwörter Mechanische Stimulation • In vitro • Humane Osteoblasten ; Key words Mechanical stimulation • Osteoblasts •¶In vitro
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary The cell activity of human bone derived cell cultures was studied after mechanical stimulation by cyclic strain at a magnitude occurring in physiologically loaded bone tissue. Monolayers of subconfluently grown human bone derived cells were stretched in rectangular silicone dishes with cyclic uniaxial movement along their longitudinal axes. Strain was applied over two days for 30 min per day with a frequency of 1 Hz and a strain magnitude of 1000 μstrain. Cyclic stretching of the cells resulted in an increased proliferation (10–48 %) and carboxyterminal collagen type I propeptide release (7–49 %) of human cancellous bone derived osteoblasts while alkaline phosphatase activity and osteocalcin release were significantly reduced by 9–25 % and 5–32 % respectively. These results demonstrate that cyclic strain at physiologic magnitude leads to an increase of osteoblast activities related to matrix production while those activities which are characteristic for the differentiated osteoblast and relevant for matrix mineralization are decreased.
    Notes: Zusammenfassung Es wurde die Zellaktivität humaner Knochenzellen nach Stimulation mit zyklischer, mechanischer Dehnung in physiologischer Größenordnung untersucht. Subkonfluente Monolayer aus humanen Knochenzellen wurden hierzu in rechteckigen Silikonschalen mit uniaxialer Bewegung gedehnt. Die Dehnung wurde an 2 aufeinanderfolgenden Tagen jeweils 30 min lang bei einer Frequenz von 1 Hz und einer Dehnungsamplitude von 1000 μstrain appliziert. Es kam zu einer Zunahme der Zellproliferation (10–48 %) und der Freisetzung an Typ-I-Kollagen-Propeptid (7–49 %). Die alkalische Phosphataseaktivität und die Osteocalcinfreisetzung waren signifikant reduziert (9–25 % bzw. 5–32 %). Diese Ergebnisse deuten darauf hin, dass zyklische Dehnungen bei physiologischer Amplitude zu einer Zunahme derjenigen Osteoblastenaktivitäten führen, die mit der Matrixbildung einhergehen. Die Zellaktivitäten, die für den differenzierten Osteoblasten charakteristisch sind und zur Matrixreifung führen, nehmen hingegen ab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/PL00003715
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    DNA damage and repair in chick embryo cells following X-irradiation in vitro as compared to mammalian cells - biochemical and physico-chemical investigations (1992)
    Springer
    Radiation and environmental biophysics 31 (1992), S. 91-100 
    Details
    ISSN: 1432-2099
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Summary Brain cells (b-cells) and liver cells (l-cells) of the chicken embryo and thymic cells (t-cells) of the rat were X-irradiated in vitro at doses of 1.25–50 Gy. When compared to t-cells, b- and l-cells exhibited1) a lower stimulation of poly (adenosine diphosphate-ribose) transferase and unscheduled DNA synthesis following X-irradiation,2) an almost fivefold higher inhibition of semiconservative DNA synthesis,3) a less condensed chromatin,4) about fourfold higher threshold doses with regard to significant effects on nucleoid sedimentation and viscometry of alkaline cellular lysates, and5) an apparently two- to threefold lower DNA repair during a 30 min post-exposure repair period. The results suggest that the lower radiation sensitivity of chicken embryo cells is attributable to an initial mechanism of DNA repair and/or DNA protection which may be closely connected to minor chromatin compactness and higher intrinsic activities of repair enzymes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01211207
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Structural transitions in wormlike micelles (1997)
    Springer
    Rheologica acta 36 (1997), S. 1-12 
    Details
    ISSN: 1435-1528
    Keywords: Surfactant solution ; salt concentration ; shear-induced structure ; Cox-Merz rule ; small-angle light scattering
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Abstract We investigate the effect of excess salt and simple shear on the dynamics and structure of semi-dilute aqueous solutions of cetyltrimethylammonium bromide and sodium salicylate. Small-amplitude oscillatory rheological measurements suggest a structural evolution from an entangled to a multi-connected network as the salt concentration is increased. Steady-shear measurements, however, show a significant departure from the Cox-Merz rule. At low salt concentrations, this departure occurs at high shear rates with η* ∞ ω−0.92±0.08 and η ∞ γ−0.51±0.06 and is attributed to the formation of large shear-induced structures. The critical shear rate γ c at which the Cox-Merz rule fails approximates the inverse of the terminal relaxation time, τ. At high salt concentrations, however, the departure occurs at both low and high shear rates and is attributed to the formation of a multi-connected network. Small-angle light scattering (SALS) under shear was used to probe the mesoscopic structure and revealed novel scattering patterns exhibiting two-fold symmetry at low salt concentration and four-fold symmetry at high salt concentration. The SALS patterns were in qualitative agreement with the formation of large scale anisotropic structures at high shear rates and a multi-connected network at high salt concentrations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00366719
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Structural transitions in wormlike micelles (1997)
    Springer
    Rheologica acta 36 (1997), S. 1-12 
    Details
    ISSN: 1435-1528
    Keywords: Key words Surfactant solution ; salt concentration ; shear-induced structure ; Cox-Merz rule ; small-angle light scattering
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Abstract We investigate the effect of excess salt and simple shear on the dynamics and structure of semidilute aqueous solutions of cetyltrimethylammonium bromide and sodium salicylate. Small-amplitude oscillatory rheological measurements suggest a structural evolution from an entangled to a multi-connected network as the salt concentration is increased. Steady-shear measurements, however, show a significant departure from the Cox-Merz rule. At low salt concentrations, this departure occurs at high shear rates with η*∝ω–0.92±0.08 and η∝˙γ–0.51±0.06 and is attributed to the formation of large shear-induced structures. The critical shear rate ˙γ c at which the Cox-Merz rule fails approximates the inverse of the terminal relaxation time, τ. At high salt concentrations, however, the departure occurs at both low and high shear rates and is attributed to the formation of a multi-connected network. Small-angle light scattering (SALS) under shear was used to probe the mesoscopic structure and revealed novel scattering patterns exhibiting two-fold symmetry at low salt concentration and four-fold symmetry at high salt concentration. The SALS patterns were in qualitative agreement with the formation of large scale anisotropic structures at high shear rates and a multi-connected network at high salt concentrations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00366719
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    The stochastic kinetics of intramolecular reactions in linear polymers (1983)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 184 (1983), S. 123-134 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: This paper deals with the kinetics of reactions of linear flexible macromolecules in solution possessing initially several reactive sites per macromolecule. It is assumed that the reactive sites interact with each other encounter-controlled and that both intra- and intermolecular reactions are possible. On the basis of the theory of stochastic kinetics in microsystems, equations were derived, describing the kinetics of intramolecular reactions as a function of the molecular weight distribution. An important application of this theoretical treatment pertains to the distribution between inter- and intramolecular reactions. A demonstration for typical reaction conditions reveals the influence of rate parameters and of the average number of reactive sites per macromolecule r̄(0) on the proportionate distribution expressed by fA = f (r̄(0)); (fA = fraction of intramolecular reactions). This function is only weakly influenced by varying the width parameter β in the case of Schulz-Zimm molecular weight distributions from β = 1 to → ∞.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1983.021840113
    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...