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  • 11
    Electronic Resource
    Electronic Resource
    Springer
    Zeitschrift für angewandte Mathematik und Physik 10 (1959), S. 438-441 
    ISSN: 1420-9039
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Physics
    Type of Medium: Electronic Resource
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  • 12
    Electronic Resource
    Electronic Resource
    Springer
    Integral equations and operator theory 22 (1995), S. 360-374 
    ISSN: 1420-8989
    Keywords: 34 A 55
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Type of Medium: Electronic Resource
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  • 13
    Electronic Resource
    Electronic Resource
    Springer
    Integral equations and operator theory 38 (2000), S. 222-250 
    ISSN: 1420-8989
    Keywords: Primary 34A55 ; 47E05 ; Secondary 34B20 ; 34L05 ; 47B25
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Abstract We consider a singular two-dimensional canonical systemJy′=−zHy on [0, ∞) such that at ∞ Weyl's limit point case holds. HereH is a measurable, real and nonnegative definite matrix function, called Hamiltonian. From results of L. de Branges it follows that the correspondence between canonical systems and their Titchmarsh-Weyl coefficients is a bijection between the class of all Hamiltonians with trH=1 and the class of Nevanlinna functions. In this note we show how the HamiltonianH of a canonical system changes if its Titchmarsh-Weyl coefficient or the corresponding spectral measure undergoes certain small perturbations. This generalizes results of H. Dym and N. Kravitsky for so-called vibrating strings, in particular a generalization of a construction principle of I.M. Gelfand and B.M. Levitan can be shown.
    Type of Medium: Electronic Resource
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  • 14
    ISSN: 1436-6274
    Keywords: Schlüsselwörter Wirbelfrakturen ; Spongiosaplastik ; Korrekturverlust ; Transplantatnekrose ; Key words Spine fractures ; Bone graft ; Loss of correction ; Transplant necrosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: In the treatment of thoracolumbar fractures of the spine an osteosynthesis in the real sense is not possible. The result of the injury is not only bony destruction but also in most cases biomechanical instability of the motion segment. The goal of operative treatment is stability. Besides internal fixation bone transplantation is necessary to achieve bony fusion. A common procedure is transpedicular bone grafting. Posterior stabilization with an internal fixator is combined with cancellous bone transplantation, which is placed into the vertebral body and the intervertebral space through the pedicles. Resection of the intervertebral disc is necessary to obtain bone healing under the protection of the implant. In a clinical study after the stabilizing operation, we found a correction loss of 30–60% that was independent of the fracture type, implant or operation procedure. The lack of healing of the bone graft was the reason for the correction loss. Besides the unfavorable vascularization of the intervertebral space which cannot be influenced by operation, the morphological arrangement and spatial expansion of the cancellous bone transplant are important for obtaining contact with the endplate of the cranially situated vertebral body. The assessment of the 3D reconstructions, generated from the digitized picture data of CT scans, shows small volumes of cancellous bone grafts with no or poor contact to the neighboring vertebral body. Our results indicate that transpedicular bone grafting cannot be recommended for the operative treatment of unstable thoracolumbar spinal fractures, since in most cases no bony fusion occurs. In our opinion combined anterior-posterior stabilizations are more often indicated.
    Notes: In der operativen Behandlung instabiler Frakturen der thorakolumbalen Wirbelsäule ist eine Osteosynthese im eigentlichen Sinn nicht möglich. Bei der Verletzung tritt nicht nur ein isolierter knöcherner Schaden ein, sondern in den meisten Fällen auch eine biomechanische Instabilität des betroffenen Bewegungssegments. Das Ziel der operativen Behandlung besteht darin, Stabilität zu erzeugen. Neben der Instrumentation mit internen Fixationssystemen ist eine Knochentransplantation erforderlich, um eine knöcherne Spondylodese zu erzielen. Die häufigste Form der Knochentransplantation ist die transpedikuläre Spongiosaplastik, bei welcher im Rahmen der dorsalen Implantation des Fixateur interne über die Pedikel des Wirbels Spongiosa in den Wirbelkörper und den Intervertebralraum plaziert wird. Voraussetzung für die knöcherne Einheilung des Transplantats unter dem Schutz des stabilisierenden Implantats ist die vorherige Resektion des intervertebralen Bandscheibengewebes. In der klinischen Studie wurden Korrekturverluste in der Größenordnung von 30–60% im Bereich der operierten Bewegungssegmente unabhängig vom Frakturtyp, Implantat oder Operationsverfahren nachgewiesen. Verantwortlich war im wesentlichen die fehlende Einheilung der transplantierten Spongiosa. Neben der ungünstigen Vaskularisation im Intervertebralraum, welche operativ unbeeinflußbar ist, kommt der morphologischen Anordnung des Transplantats, seiner räumlichen Ausdehnung und damit der Möglichkeit, mit dem benachbarten Wirbel in Kontakt zu kommen, eine besondere Bedeutung zu. Die Auswertung von 3D-Rekonstruktionen, welche aus den CT-Bilddaten gewonnen wurden, zeigt unbefriedigend kleine Spongiosavolumina, die keinen oder eine nur ungenügenden Kontakt zum Nachbarwirbel herstellen. Die vorliegenden NMR-Untersuchungen belegen eine mangelnde Vitalität der transplantierten Spongiosa. Da überwiegend keine knöcherne Fusion von instabilen Bewegungssegmenten oder nur unter Entwicklung von erheblichen Korrekturverlusten eintritt, ist die transpedikuläre Spongiosaplastik nach den obigen Ergebnissen nicht für die operative Stabilisierung thorakolumbaler Frakturen geeignet. Als Konsequenz aus den Ergebnissen muß die Indikation zur kombiniert dorso-ventralen Stabilisierung häufiger gestellt werden. Möglicherweise werden in Zukunft endoskopische minimalinvasive Techniken weiter perfektioniert, um invasive, patientenbelastende Verfahren zu vermeiden und das Komplikationsrisiko zu senken.
    Type of Medium: Electronic Resource
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  • 15
    Electronic Resource
    Electronic Resource
    Springer
    Trauma und Berufskrankheit 1 (1998), S. 24-32 
    ISSN: 1436-6274
    Keywords: Schlüsselwörter Distale Radiusfraktur ; Operationsverfahren ; Fixateur externe ; Spongiosaplastik ; Key words Distal radial fractures ; Operative treatment ; External fixation ; Bone-grafting
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Because non-operative treatment of distal radial fractures usually has a poor outcome there has been a trend towards operative treatment, targeting the anatomical reconstuction of the distal radius and the joint. Analysis of the fracture based on the AO classification allows rational treatment and makes the results comparable. A detailed indication list for more diffentiated therapy of these radial fractures and a detailed description of the operative technique are given. From 1993 to 1997, 174 patients were treated with external fixation of the AO in the Berufsgenossenschaftlichen Unfallklinik Ludwigshafen (trauma center level one). Type C fractures were found in 90%. Two-thirds of the patients were women. Three different types of treatment have been compared: (1) external fixation; (2) external fixation and change to internal fixation with bone-grafting; (3) external fixation and bone-grafting. Similar functional results were achieved in all groups. The loss of repositioning in the follow-up was smallest in group 3. The following complications were found: local pin-tract infections in 15 patients, operations because of hematoma in the pelvic region of bone harvesting in 5 patients and 10 severe dislocations in the group with internal fixation. External fixation including bone-grafting showed the best results in severe type C fractures of the distal radius.
    Notes: Bei der Versorgung der körperfernen Radiusfraktur ist aufgrund unbefriedigender Ergebnisse nach konservativer Behandlung ein Wechsel zur operativen Therapie mit dem Ziel der anatomischen Gelenkrekonstruktion zu beobachten. Eine Frakturanalyse basierend auf der AO-Klassifikation ermöglicht eine bedarfsgerechte Therapieplanung und den Vergleich der Ergebnisse. Nach einer Darstellung der Indikationen zur differenzierten Therapie der distalen Radiusfraktur werden die Ergebnisse der in den Jahren von 1993–1997 in der BG Unfallklinik Ludwigshafen mit Fixateur externe (FE) behandelten Patienten (n = 174) unter besonderer Berücksichtigung der Operationstechnik analysiert. C-Frakturen lagen nach der Klassifikation der AO zu 90% vor, Frauen waren zu ⅔ betroffen. Drei Behandlungsgruppen wurden unterschieden: 1. FE, 2. FE und Wechsel auf ein internes Verfahren mit Spongiosaplastik sowie 3. FE und Spongiosaplastik. Bei vergleichbarer Funktion beobachteten wir den geringsten Korrekturverlust in Gruppe 3. An Komplikationen traten auf: lokale Pininfekte bei 15 Patienten, 5 Hämatomrevisionen an der Spongiosaentnahmestelle am Beckenkamm und 10 Dislokationen nach Verfahrenswechsel auf eine Plattenosteosynthese. Die Stabilisierung im Fixateur externe mit begleitender (ein- oder zweizeitiger) Spongiosaplastik scheint die besten Ergebnisse bei der Versorgung der komplexen C-Frakturen des distalen Radius zu erbringen.
    Type of Medium: Electronic Resource
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  • 16
    Electronic Resource
    Electronic Resource
    Springer
    Il nuovo cimento della Società Italiana di Fisica 18 (1996), S. 353-357 
    ISSN: 0392-6737
    Keywords: Mössbauer spectra ; Spectra ; photodissociation and photoionization of biomolecules ; bioluminescence ; Measurement of rate constants ; reaction cross-sections and activation energy ; Conference proceedings
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Summary Partial photodissociation of two carbonmonoxy-porphyrin complexes, a bridged and a fenced one, has been achieved. The results from monitoring the recombination point to an important influence of the solvent matrix on the recombination rates.
    Type of Medium: Electronic Resource
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  • 17
    ISSN: 0392-6737
    Keywords: Phonons and vibrations in crystal lattices ; Solid-liquid transitions ; Thermodynamic properties and entropy ; Conference proceedings
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Summary Dynamic properties of ultrafine clusters of γ-Fe2O3 (ferric oxide, FO) were studied by Mössbauer spectroscopy and by thermodynamic analysis. The data obtained for FO clusters allowed the conclusion that dynamic properties of clusters as well as the decrease of melting point and the appearance of a gap between freezing and melting points depend on intracluster atomic mobility. Intracluster atomic mobility in FO clusters was shown to increase by the action of surfactants which decrease intercluster interactions. The increase in intracluster atomic mobility was suggested to proceed via formation of a solid-liquid state.
    Type of Medium: Electronic Resource
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  • 18
    ISSN: 1432-1076
    Keywords: Key words Glucosephosphate isomerase ; haemolytic anaemia ; enzyme mutants
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Biochemical and molecular genetic studies were performed on the enzyme variants of two patients compound heterozygous for glucose phosphate isomerase (GPI) deficiency, both suffering from severe haemolytic anaemia. The enzymes of case 1 (GPI `Zwickau') and case 2 (GPI `Nordhorn' [25]), revealed reduced GPI activity and remarkable thermolability. Glucose-6-phosphate (Gluc-6-P) concentration was elevated 2.3 times in case 1 and 3.8 times in case 2. Sequencing the patients' GPI genes showed four different point mutations, two of them involving highly conserved amino acids. The c1039 C→T substitution, found in the gene of GPI `Zwickau', has been described recently [30] and causes an Arg 347→Cys substitution close to the putative catalytic site. The second mutation in this case is a novel c1538 G→A substitution causing a Trp→stop mutation at position 513 apparently resulting in premature RNA degradation thus resulting either in a complete lack of protein or a protein which does not show GPI activity. In the gene of GPI `Nordhorn' a c1028 A→G mutation was discovered, also previously described [1, 9] causing a Gln 343→Trp substitution. The second mutation was a novel splice site mutation at the border of intron 15 to exon 16: IVS15-(-2) A→C which leads to an aberrant splicing of exon 16, thus resulting either in a truncated and most likely inactive enzyme or in no protein at all. Conclusion Biochemical and molecular genetic studies performed with the enzyme variants GPI `Zwickau' and GPI `Nordhorn' showed that in both cases the simultaneous occurrence of a single amino acid sub‐stitution affecting the active site, together with a nonsense mutation leading to the loss of major parts of the enzyme probably explains the severe clinical course of the disease.
    Type of Medium: Electronic Resource
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  • 19
    ISSN: 1432-1017
    Keywords: Key words Carbonmonoxy-Myoglobin ; Recombination kinetics ; Mössbauer spectroscopy ; Scaling law ; Activated tunneling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Abstract We have studied the recombination kinetics of carboxymyoglobin (after photodissociation of the CO ligand) by Mössbauer spectroscopy for temperatures in the range 4.2 – 60 K. The observed kinetics display non-exponential behaviour which was monitored over periods of a few days. It is shown that the time dependence of the kinetics can be reduced to a single universal function of the temperature-dependent variable (t/τ 1/2(T)) β(T) . The half-decay time τ 1/2(T) and the scaling parameter β(T) are analysed for the presence of tunneling effects. The non-Arrhenius temperature dependence of the half-decay time below 60 K is interpreted as activated tunneling in models with an Eckart barrier or a fluctuating barrier.
    Type of Medium: Electronic Resource
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  • 20
    Electronic Resource
    Electronic Resource
    Springer
    European journal of orthopaedic surgery & traumatology 7 (1997), S. 195-198 
    ISSN: 1432-1068
    Keywords: Fractures of the head of the tibia ; Osteitis ; Infection ; Surgical flaps ; Fracture de l'extrémité proximale du tibia ; Ostéite ; Infection ; Lambeaux locaux
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé Nous avons examiné au total 52 patients présentant avec infection après fracture de l' extrémité proximale du tibia entre 1988 et 1992. 26 patients étaient transférés d'autres hôpitaux avec une ostéite évolutive, 26 patients étaient traités entièrement dans notre hôpital. Nous discutons l'étiologie de l'infection de ces deux groupes. Tous les patients ont été traités avec débridement radical. Une stabilisation osseuse fut nécessaire dans 73 % de cas. Nous avons réalisé une résection segmentaire à cause d'une large infection dans 3 cas. La perte de substance causée par cette intervention a été fermée par une lambeau local dans 11 cas. Ainsi nous avons pu arrêter l'infection dans 41 cas mais seulement 7 patients peuvent être considérés comme entièrement guéris (13 %). Dans 9 cas l'amputation a due être effectuée. Malgré le succès thérapeutique concernant l'infection elle même, le résultat fonctionnel est resté mauvais. C'est pourquoi éviter l'infection reste le point le plus important traitement d'une fracture. Le pourcentage des infections peut être abaissé en utilisant un type d'osteosynthèse adapté aux besoins des tissus mous. Il faut fermer les pertes de substance initiales d'une fracture ouverte ou causées par le traitement initial par un lambeau de muscle jumeau (musculus gastrocnemius) après un délai de quelques jours. Soigner les tissus mous correctement est au moins aussi important que de reconstruire les fragments osseux, lorsque l'on traite une fracture de l'extrémité proximale du tibia.
    Notes: Summary A total of 52 patients with infection after fracture of the proximal tibia were retrospectively reviewed from 1988 to 1995. 26 patients were transfered from peripheral hospitals with active osteitis, while 26 patients had been primarily treated in our hospital. Refering to the total group of patients, infection inducing factors are discussed critically. All patients underwent radical debridement. Restoration of bone stability had to be done in 73 %. Due to the extent of infection, segmental resection had to be perfomed on 3 patients. Resulting soft tissue defects were closed with local flaps in 11 cases. Infection was controlled in 41 patients, but only 7 could be classified as “cured”. Nine patients had amputations after failure of treatment. Despite successful therapy, the functional results are poor. Therefore, avoiding infection, has top priority in post fracture treatment. The correct form of osteosynthesis adapted to the soft tissue lesion can lower infection rates significantly. Soft tissue defects, resulting from open fractures or after primary treatment, have to be closed by gastrocnemius flap transfer within a short time. The management of the soft tissue is at least as important as the reconstruction of the bone in the treatment of fractures of the head of the tibia.
    Type of Medium: Electronic Resource
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