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  • 11
    Digitale Medien
    Digitale Medien
    Springer
    Insectes sociaux 46 (1999), S. 131-136 
    ISSN: 1420-9098
    Schlagwort(e): Key words:Vespula, Polistes, Vespidae, foraging, resource choice.
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary: The role of visual cues provided by resident wasps on resource choice by yellowjacket and paper wasp foragers was investigated. Large spring queen yellowjackets and small early season yellowjacket foragers (Vespula germanica, Vespula maculifrons, and Vespula vidua) were extracted in hexane to remove odors and posed as though feeding at petri dish feeders bearing daisy-like flower models, equipped with microcapillary feeding tubes, and containing 1:3 honey:water solution. An array of five feeders was presented to foragers at a suburban and a woodland site in Saratoga Springs, New York. The visual cues provided by resident wasps influenced resource choice by approaching social wasp foragers. Vespula germanica, an introduced yellowjacket species that tends to dominate at rich resources, was the only wasp visiting the suburban feeders. Foragers of this species preferentially fed on feeders and flowers with posed wasps and fed most often next to large wasps. Polistes fuscatus foragers at the woodland site similarly preferred to feed on occupied feeders and flowers. Vespula maculifrons and V. consobrina preferentially visited unoccupied feeders. Individual V. maculifrons, V. consobrina and V. vidua foragers that landed on occupied feeders all preferentially visited unoccupied flowers on those feeders. Vespula vidua and V. flavopilosa foragers did not demonstrate a feeder preference based on the presence/absence of posed wasps. Vespula consobrina foragers that visited occupied feeders preferred those occupied by extracted V. maculifrons queens and workers; no other wasps showed species based landing preferences.
    Materialart: Digitale Medien
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  • 12
    Digitale Medien
    Digitale Medien
    Springer
    The chemical educator 3 (1998), S. 1-11 
    ISSN: 1430-4171
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract An undergraduate instrumental analysis laboratory exercise is presented for the characterization of light emission generated using electrochemiluminescence (ECL). ECL involves the electrochemical generation of excited states and as such is a sensitive probe of electrochemical, electron-transfer and energy-transfer processes at electrified interfaces. An objective of this experiment is to have students develop an understanding of the mechanisms and factors affecting ECL. Also, this exercise gives students experience in coupling two powerful analytical techniques: electrochemistry and spectroscopy. With the recent development of ECL technology for use in clinical diagnostics applications, this exercise also facilitates discussions on the importance of basic research and the practical aspects of taking a technology from the bench top to commercial reality.
    Materialart: Digitale Medien
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  • 13
    ISSN: 1432-1238
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 14
    ISSN: 0949-2925
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Informatik
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 15
    ISSN: 1438-2199
    Schlagwort(e): Rat striatum ; Medium spiny neuron ; Adenosine AZA receptor ; NMDA receptor channel ; Whole-cell patch clamp
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Whole-cell patch clamp experiments were carried out in rat striatal brain slices. In a subset of striatal neurons (70–80%), NMDA-induced inward currents were inhibited by the adenosine AZA receptor selective agonist CGS 21680. The non-selective adenosine receptor antagonist 8-(p-sulphophenyl)-theophylline and the AZA receptor selective antagonist 8-(3chlorostyryl) caffeine abolished the inhibitory action of CGS 21680. Intracellular GDP-β-S, which is known to prevent G protein-mediated reactions, also eliminated the effect of CGS 21680. Extracellular dibutyryl cAMP, a membrane permeable analogue of cAMP, and intracellular Sp-cAMPS, an activator of cAMP-dependent protein kinases (PKA), both abolished the CGS 21680-induced inhibition. By contrast, Rp-cAMPS and PKI 14–24 amide, two inhibitors of PKA had no effect. Intracellular U-73122 (a phospholipase C inhibitor) and heparin (an inositoltriphosphate antagonist) prevented the effect of CGS 21680. Finally, a more efficient buffering of intracellular Ca2+ by a substitution of EGTA (11 mM) by BAPTA (5.5 mM) acted like U-73122 or heparin. Hence, AZA receptors appear to negatively modulate NMDA receptor channel conductance via the phospholipase C/inositoltriphosphate/Ca2+ pathway rather than the adenylate cyclase/PKA pathway.
    Materialart: Digitale Medien
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  • 16
    Digitale Medien
    Digitale Medien
    Springer
    Astrophysics and space science 233 (1995), S. 67-70 
    ISSN: 1572-946X
    Schlagwort(e): Interstellar Molecules ; Supernova Remnants ; Infrared Spectroscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract We present spectroscopy of the molecular shock in the supernova remnant IC 443. The H2 level populations in IC 443 are nearly identical to Orion Peak 1 (Brand et al. 1988; Parmar et al. 1994) and are consistent with a partially dissociative J-shock. The similarity with Orion suggests the shock processes which dominate the emission in both regions are essentially identical.
    Materialart: Digitale Medien
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  • 17
    ISSN: 1573-4838
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin , Technik allgemein
    Notizen: 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.
    Materialart: Digitale Medien
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  • 18
    ISSN: 1573-4838
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin , Technik allgemein
    Notizen: 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.
    Materialart: Digitale Medien
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  • 19
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Molecular modelling ; Molecular mechanics calculations ; Permethylated α-, β- and γ-cyclodextrins ; Interaction mechanism
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary The capillary gas chromatographic retention behavior of α-pinene and tricyclene has been investigated on stationary phases of different polarities. On all but one of the columns employed, tricyclene eluted before α-pinene; only permethylated β-cyclodextrins dissolved in moderately polar polisiloxanes gave a reversed elution order. The intermolecular interactions which caused the unexpected retention behavior were investigated in detail, applying methods of computer simulation. To achieve this, we have developed a calculation algorithm on the basis of molecular mechanical optimizations and programmed it in a macro. This makes it possible to systematically investigate a given configuration space in which all the possible interactions can take place. It was shown that permethylated β-cyclodextrin as host molecule for both guest molecules offers an optimum cavity size. As a result the number of energetically favorable contacts between host and guest molecules as well as the strength of the interactions in this stationary phase were larger. As a consequence the elution order, normally only influenced by the vapor pressure of the compounds at a given temperature, was changed. Nonspecific interactions played an especially important role for these kinds of substances.
    Materialart: Digitale Medien
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  • 20
    ISSN: 1433-044X
    Schlagwort(e): Key words Car accident • Fracture of the foot • Injury mechanism • Long-term outcome ; Schlüsselwörter PKW-Unfall • Fußfraktur • Verletzungsmechanismus • Langzeitfolgen
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Bei 6378 Verkehrsunfällen mit 8931 Verletzten zwischen 1973 und 1989 im Großraum Hannover wurden 3267 PKW-Insassen mit Frakturen registriert. Davon hatten 148 (4,5 %) Personen Frakturen im Fußbereich erlitten. Die Unfalldaten wurden in Hinblick auf Verletzungsentstehung, -art und -ausmaß ausgewertet und die Verletzungsfolgen anhand von Langzeituntersuchungen evaluiert. Bei der Entstehung der Fußfrakturen spielte die Deformierung des Fußraums die wesentliche Rolle. Fahrer und Beifahrer erlitten ähnlich schwere Verletzungen. Bei den 286 Frakturen war der Vorfuß am häufigsten betroffen (45 %), gefolgt von OSG (35 %), Mittelfuß (11 %) und Rückfuß (6 %). Der Anteil der offenen Frakturen betrug 5 %. Die Klassifikation erfolgte nach der „Abbreviated Injury Scale“ (AIS) für die untere Extremität. Die Langzeitfolgen wurden anhand der fußverletzungsbedingten Minderung der Erwerbsfähigkeit (MdE) im Verhältnis zur gesamten MdE abgeschätzt. Diese Auswertung ergab, daß die Fußfrakturen vor allem bei erheblichen Begleitverletzungen bei der Primäruntersuchung oft nicht erkannt oder unterschätzt wurden. Die Langzeitfolgen gingen häufig mit einer erheblichen fußverletzungsbedingten Invalidisierung einher.
    Notizen: Summary During 1973 and 1989, 6,378 car accidents with 8,931 injured persons were evaluated in the area of Hannover. 3,267 car drivers and passengers sustained fractures overall and 148 (4,5 %) fractures of the foot. A major role in the ethiology of the foot fractures evolves from the deformation of the foot room. Driver and front seat passenger showed similar injuries. Among the 286 single fractures, the forefoot was affected most often (45 %), followed by ankle (38 %), midfoot (11 %) and hindfoot (6 %). 5 % were open fractures. The long term results were estimated upon the limitation of working ability caused by the foot injury in relation to the entire working ability. The evaluation concludes that the foot fractures especially in combination with other injuries were frequently not recognized within the primary examination and therefore underestimated. The long-term outcome leaded to a high degree of impairment due to foot fractures.
    Materialart: Digitale Medien
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