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  • 11
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: The filamentous bacterium Streptomyces coelicolor undergoes a complex process of morphological differentiation involving the formation of a dense lawn of aerial hyphae that grow away from the colony surface into the air to form an aerial mycelium. Bald mutants of S. coelicolor, which are blocked in aerial mycelium formation, regain the capacity to erect aerial structures when exposed to a small hydrophobic protein called SapB, whose synthesis is temporally and spatially correlated with morphological differentiation. We now report that SapB is a surfactant that is capable of reducing the surface tension of water from 72 mJ m−2 to 30 mJ m−2 at a concentration of 50 μg ml−1. We also report that SapB, like the surface-active peptide streptofactin produced by the species S. tendae, was capable of restoring the capacity of bald mutants of S. tendae to erect aerial structures. Strikingly, a member (SC3) of the hydrophobin family of fungal proteins involved in the erection of aerial hyphae in the filamentous fungus Schizophyllum commune was also capable of restoring the capacity of S. coelicolor and S. tendae bald mutants to erect aerial structures. SC3 is unrelated in structure to SapB and streptofactin but, like the streptomycetes proteins, the fungal protein is a surface active agent. Scanning electron microscopy revealed that aerial structures produced in response to both the bacterial or the fungal proteins were undifferentiated vegetative hyphae that had grown away from the colony surface but had not commenced the process of spore formation. We conclude that the production of SapB and streptofactin at the start of morphological differentiation contributes to the erection of aerial hyphae by decreasing the surface tension at the colony surface but that subsequent morphogenesis requires additional developmentally regulated events under the control of bald genes.
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  • 12
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    ISSN: 0365-9496
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 13
    ISSN: 1432-1238
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
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  • 14
    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.
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  • 15
    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.
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  • 16
    ISSN: 1618-2650
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
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  • 17
    ISSN: 1438-2199
    Keywords: Rat striatum ; Medium spiny neuron ; Adenosine AZA receptor ; NMDA receptor channel ; Whole-cell patch clamp
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: 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.
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  • 18
    ISSN: 1572-946X
    Keywords: Interstellar Molecules ; Supernova Remnants ; Infrared Spectroscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: 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.
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  • 19
    ISSN: 1435-0130
    Keywords: Key words Carpal tunnel syndrome ; Long incision ; Short incision ; Endoscopic release
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  The results of open carpal tunnel release using a short incision (2.5 cm) have been compared with those following a long incision (4.5 cm) in a prospective randomized study. Eighty patients were operated upon with a follow-up rate of 100%. The variables examined included grip strength, key and pulp pinch strength, sensory function and scar tenderness. Subjective variables such as tingling, numbness and night symptoms were specifically enquired into, and time for return to work was noted. The examinations took place pre-operatively, as well as one, two, three and six weeks post-operatively. Median time for return to work was 21 days for the short incision group and 18 days for the long incision group. The long incision resulted in a significant 10% loss of strength only at week three, otherwise no significant difference was found between the results of the two groups.
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  • 20
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 111 (1999), S. 386-397 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: We have studied the ultraviolet laser-induced desorption of NO molecules from an epitaxial film of NiO(100) on Ni(100) for pulse durations of 550 fs and at a photon energy of 3.95 eV. For applied laser intensities up to 450 MW/cm2, the highest intensities employed in this work, a linear dependence of the desorption yield on the laser intensity is observed. A desorption cross section of (1.9±0.3)⋅10−17 cm2 is then derived. The molecules are detected with rovibrational state selectivity by (1+1)-REMPI via the A 2Σ+(v′=0,1,2,3)←X 2Π(v″=0,1,2,3) γ-band transitions. The rotational population distributions are nonthermal, with rotational temperatures of about 290 K at low and of about 770 K at high rotational energies. The relative populations in the 2Π1/2 and 2Π3/2 fine-structure states and of the Λ-doublet states are examined for the given set of (v″,J″) quantum numbers. The vibrational states v″〉0 are significantly populated approaching vibrational temperatures of 3800 K. Velocity distributions of the desorbed molecules are measured for individual rovibrational states. Bimodal distributions with a distinct rotational-translational coupling are observed. Further, molecules desorbing in the excited fine-structure state 2Π3/2 show a higher velocity than those desorbing in 2Π1/2. The results are compared with earlier ones obtained for the same system with nanosecond desorption pulses at hν=6.4 eV. © 1999 American Institute of Physics.
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