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  • 1990-1994  (7)
  • 1955-1959
  • 1940-1944
  • 1992  (7)
  • 1
    Electronic Resource
    Electronic Resource
    Studies on the prenatal toxicity of toluene in rabbits following inhalation exposure and proposal of a pregnancy guidance value (1992)
    Springer
    Archives of toxicology 66 (1992), S. 373-381 
    Details
    ISSN: 1432-0738
    Keywords: Toluene ; Maternal toxicity ; Embryotoxicity ; Teratogenicity ; Rabbit ; Inhalation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Prenatal toxicity of toluene was determined in two separate studies by inhalation exposure of Himalayan rabbits. In the first study 15 artificially inseminated females per group were exposed to 30, 100, or 300 ppm and in the second study 20 artificially inseminated females per group inhaled 100 or 500 ppm. In each case the rabbits were exposed for 6 hours per day from day 6 post-insemination (p. i.) to day 18 p. i. The respective controls inhaled conditioned clean air under the same exposure conditions. No signs of maternal toxicity were observed. All data obtained on gestational parameters were found to be within the variation range reported for this rabbit strain. The fetal external, soft tissue and skeletal findings were seen in toluene exposed fetuses in a frequency similar to the corresponding and/or historical controls. Differences observed between the groups were not concentration dependent and were considered incidental rather than compound related. Therefore, toluene was not embryotoxic, fetotoxic, or teratogenic for rabbits exposed during the period of organogenesis. The highest concentration tested under these conditions (500 ppm) was found to be a no-observable-adverse-effect level (NOAEL) for both the adult and the fetal Himalayan rabbit. Based on these and previous results of animal studies of prenatal toxicity, a safety or uncertainty factor approach is considered for setting limits of exposure for women at workplaces. A pregnancy guidance value of 20 ppm is proposed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02035125
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  • 2
    Electronic Resource
    Electronic Resource
    Genetic polymorphism of the gene encoding the outer surface protein A (OspA) of Borrelia burgdorferi (1992)
    Springer
    Medical microbiology and immunology 181 (1992), S. 57-70 
    Details
    ISSN: 1432-1831
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The genes coding for the outer surface protein (OspA) of Borrelia burgdorferi, the causative agent of Lyme borreliosis have been cloned and sequenced. Two German strains (skin isolate PKo and cerebrospinal fluid isolate PBi) have been analyzed. Using an OspA-specific monoclonal antibody (L32 2E7) for immunological screening of a genomic pUC 18 library of B. burgdorferi strain PKo, an OspA-producing clone was detected and subclones containing the open reading frame were constructed. The gene coding for the OspA protein of B. burgdorferi strain PBi was amplified using polymerase chain reaction (PCR) and cloned in pUC8. The open reading frame of both ospA genes consists of 822 nucleotides corresponding to a protein of 273 amino acids. Both proteins have a calculated molecular mass of 29.6 kDa. Molecular analysis revealed significant differences between each other and to already-published sequences of ospA of B. burgdorferi strains B31, ZS7 and N40 (the ospA genes of B31, ZS7 and N40 are nearly identical). The deduced amino acid sequences of the OspA protein of strains PKo and PBi showed a homology of 83% to each other and 77% and 80%, respectively, to OspA protein of strain B 31. The three proteins contain a variable middle region, whereas the N and the C terminus are conserved. This unexpected high dissimilarity of the ospA genes may be important in respect to vaccination studies and diagnostic procedures (i.e., development of PCR primers or serodiagnostic antigens). Moreover, the molecular heterogeneity of OspA confirms three out of seven immunologically defined OspA serotypes of a recently proposed OspA serotyping system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00189424
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Microscopic analysis of autograft bone applied at the interface of porous-coated devices in human cancellous bone (1992)
    Springer
    International orthopaedics 16 (1992), S. 349-358 
    Details
    ISSN: 1432-5195
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé Nous avons étudié la réponse de l'os spongieux humain et le taux de remodelage osseux aprés insertion chirurgicale de copeaux d'os autologue (COA) à l'interface entre os et implants poreux. Au cours du premier temps d'une arthroplastie totale bilatérale du genous, nous avons implanté, chez 7 malades consentants, deux dispositifs à revêtement poreux dans le condyle interne du fémur opposé. L'un a été recouvert de COA avant d'être mis en place, l'autre a été placé tel quel pour servir de contrôle. Ces dispositifs ont été explantés en bloc avec l'os avoisinant lors de la deuxième arthroplastie, 6 à 49 semaines après leur insertion. Les études en microscopie électronique ont montré une augmentation significative (p≤0.05) de la quantité d'os sur la surface poreuse recouverte de COA. Le taux d'apposition minérale (TAM) moyen était de 1,04±0,20 μm/jour à l'interface et de 0,81±0,09 μm/jour au niveau de l'os spongieux adjacent. Pour les implants non greffés le TAM était de 1,03±0,38 μm/jour à l'interface et de 0,79±0,19 μm/jour au niveau du spongieux périphèrique. Le TAM à l'interface des implants à revêtement poreux est significativement augmenté (p±0.05) par rapport à l'os receveur avoisinant.
    Notes: Summary This study describes the response of human cancellous bone when autologous bone chips are added at operation to the interface between host bone and porous-coated implants. During the first operation of a staged bilateral total knee arthroplasty, seven patients consented to have paired porous-coated devices implanted into their opposite medial femoral condyle. One device of each pair had autologous bone chips applied to the porous-coating, and the other was not grafted and was a control. The devices were removed en bloc at the second total knee arthroplasty 6 to 49 weeks later. Backscattered electron imaging showed significantly more bone (p≤0.05) in the porous-coating of the implant treated with autologous bone chips which significantly increased (p≤0.05) the amount of bone available at the interface. The grafted devices had a mineral apposition rate of 1.04±0.20 μm/day for the interface and 0.81±0.09 μm/day for the peripheral bone. This compared with corresponding figures of 1.03±0.38 μm/day and 0.79±0.19 μm/day at the ungrafted devices. The mineral apposition rate at the interface of the porous-coated implants was significantly increased (p≤0.05) relative to the host bone in the periphery. Our results support the view that autologous bone chips are effective in attaching cementless porous-coated total knee replacements to the human skeleton by bone ingrowth.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00189618
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Das Grenzflächenverhalten von SiC und seine Anwendung in faserverstärktem Aluminium (1992)
    Weinheim : Wiley-Blackwell
    Materialwissenschaft und Werkstofftechnik 23 (1992), S. 267-271 
    Details
    ISSN: 0933-5137
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: The interface Behavior of Sic and its Application to Fiber Reinforced AluminiumSiC barrier layers on carbon fibers can be deposited by thermal decomposition of methyl trichlorosilane. The influence of the CVD parameters on their structure and composition is presented by the results of surface-analytical and electronmicroscopical investigations. During the preparation of fiber reinforced Al chemical reactions and segregation effects result in the formation of undesirabled phases at the interface between matrix and fiber. The stability of the barrier layer is negativly influenced by it.
    Notes: SiC-Barriereschichten auf Kohlenstoffasern lassen sich durch thermische Zersetzung von Methyltrichlorsilan abscheiden. Der Einfluß der CVD-Parameter auf deren Struktur und Zusammensetzung wird anhand der Ergebnisse von oberflächenanalytischen und elektronenmikroskopischen Untersuchungen dargestellt. Bei der Herstellung von faserverstärktem Al kommt es infolge von chemischen Reaktionen und Segregationen zur Bildung von unerwünschten Phasen an der Grenzfläche zwischen Matrix und Faser. die die Stabilität der Barriereschichten negativ beeinflussen.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mawe.19920230712
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  • 5
    Electronic Resource
    Electronic Resource
    Collective and molecular dynamics in ferroelectric liquid crystals: from low molar to polymeric and elastomeric systems (1992)
    New York, NY : Wiley-Blackwell
    Polymers for Advanced Technologies 3 (1992), S. 249-255 
    Details
    ISSN: 1042-7147
    Keywords: Ferroelectric liquid crystals ; Polymers ; Dielectric spectroscopy ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Broadband dielectric spectroscopy delivers in the frequency range from 10 Hz to 1010 Hz two collective dielectric loss processes (soft and Goldstone modes) and one molecular relaxation (β-relaxation). The soft mode and Goldstone mode are assigned to the fluctuation of the amplitude and the phase of the helical superstructure. The β-relaxation corresponds to the libration (hindered rotation) of the mesogene around its long molecular axis. At the SmA-SmC* phase transition this process does not split or broaden, and the temperature dependence of its relaxation rate does not show any deviation from an Arrhenius-like behavior. Its dielectric strength does not decline at the SmA-SmC* phase transition. These experimental findings are in contrast to the common explanation of the origin of the saturation polarization (“induced spontaneous polarization”), which is based on the existence of a “free” rotation inside the SmA phase and its strong hindrance in the ferroelectric SmC* phase. Furthermore, the high frequency results require a reformulation for the (generalized) Landau theory as applied to the SmA-SmC* phase transition. In comparing low molar mass and polymeric (elastomeric) FLC, the collective and molecular dynamics are qualitatively similar, independent of the molecular architecture (e.g. side-chain, combined main- and side-chain or crosslinked systems).
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pat.1992.220030509
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  • 6
    Electronic Resource
    Electronic Resource
    Hyaluronan solution as a cartilage antidesiccant (1992)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 26 (1992), S. 303-317 
    Details
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: During arthrotomy, desiccation of the articular cartilage of synovial joints by the ambient environment of the operating room causes chondrocyte death and may promote degenerative changes within the joint. This study documents the efficacy of a biomaterial, hyaluronan (HY) solution, to maintain chondrocyte viability during desiccation. Rabbit patellar articular cartilage was air-dried for 2 h with and without application of the HY solution. As assessed by 35S04 uptake and autoradiography, the HY solution helped maintain chondrocyte viability, when compared to air dried specimens (p ≤ 0.02). HY solution applied to the articular surfaces of joints undergoing arthrotomy may offset the detrimental effects of desiccation, such as chondrocyte death and degenerative joint changes.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jbm.820260304
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  • 7
    Electronic Resource
    Electronic Resource
    An Electron Spectroscopic Investigation of Attenuation Lengths of Electrons in SiO2 in the Energy Range 450 eV ≤ Ekin ≤ 3100 eV (1992)
    Chichester [u.a.] : Wiley-Blackwell
    Surface and Interface Analysis 18 (1992), S. 821-823 
    Details
    ISSN: 0142-2421
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: An experimental determination of the attenuation lengths of electrons in SiO2 by means of XPS and x-ray-excited Auger electron spectra gave a remarkable agreement with recently published inelastic mean free path data.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/sia.740181207
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    Paper (German National Licenses)
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