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  • 1
    Online-Ressource
    Online-Ressource
    American Vacuum Society ; 2018
    In:  Biointerphases Vol. 13, No. 6 ( 2018-12-01)
    In: Biointerphases, American Vacuum Society, Vol. 13, No. 6 ( 2018-12-01)
    Kurzfassung: Frogs capture their prey with a highly specialized tongue. Recent studies indicate this tongue is covered with fibril-forming mucus that acts as a pressure sensitive adhesive. However, no analysis of the interfacial chemistry of frog tongue mucus has been performed. The goal of this study is to examine the chemical structure of the surface of mucus after a tongue strike. Previous studies of mucus from other animals suggest that mucus from a frog's tongue consists of mucins—serine-, threonine-, and proline-rich glycoproteins. Therefore, the authors expect to observe chemical bonds associated with glycoproteins, as well as fibrils formed at the mucus–tongue interface. To test this hypothesis, they collected both near-edge x-ray absorption fine structure (NEXAFS) microscopy images and sum frequency generation (SFG) vibrational spectra from layers of mucus left after frog tongue strikes on cleaned glass slides. NEXAFS imaging demonstrates a uniform distribution of amide, hydroxyl, and carbon–carbon bonds across the mucus surface. Difference spectra of individual N1s and C1s K-edge spectra pulled from these images indicate a structure consistent with fibril formation as well as disorder of oligosaccharide groups near the mucus surface. C—H region SFG spectra reveal surface active modes which likely stem from serine and threonine within the mucin protein. Combined, this work suggests that glycoproteins are well-ordered at the mucus–tongue interface.
    Materialart: Online-Ressource
    ISSN: 1934-8630 , 1559-4106
    Sprache: Englisch
    Verlag: American Vacuum Society
    Publikationsdatum: 2018
    ZDB Id: 2234510-3
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 2
    Online-Ressource
    Online-Ressource
    Elsevier BV ; 2019
    In:  Journal of Insect Physiology Vol. 117 ( 2019-08), p. 103908-
    In: Journal of Insect Physiology, Elsevier BV, Vol. 117 ( 2019-08), p. 103908-
    Materialart: Online-Ressource
    ISSN: 0022-1910
    RVK:
    Sprache: Englisch
    Verlag: Elsevier BV
    Publikationsdatum: 2019
    ZDB Id: 1482429-2
    SSG: 12
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 3
    In: The Science of Nature, Springer Science and Business Media LLC, Vol. 102, No. 7-8 ( 2015-8)
    Materialart: Online-Ressource
    ISSN: 0028-1042 , 1432-1904
    RVK:
    Sprache: Englisch
    Verlag: Springer Science and Business Media LLC
    Publikationsdatum: 2015
    ZDB Id: 1462930-6
    ZDB Id: 2075363-9
    ZDB Id: 123257-5
    SSG: 11
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 4
    In: Journal of Anatomy, Wiley, Vol. 235, No. 2 ( 2019-08), p. 357-378
    Kurzfassung: Computed‐tomography‐derived ( CT ‐derived) polymesh surfaces are widely used in geometric morphometric studies. This approach is inevitably associated with decisions on scanning parameters, resolution, and segmentation strategies. Although the underlying processing steps have been shown to potentially contribute artefactual variance to three‐dimensional landmark coordinates, their effects on measurement error have rarely been assessed systematically in CT ‐based geometric morphometric studies. The present study systematically assessed artefactual variance in landmark data introduced by the use of different voxel sizes, segmentation strategies, surface simplification degrees, and by inter‐ and intra‐observer differences, and compared their magnitude to true biological variation. Multiple CT ‐derived surface variants of the anuran (Amphibia: Anura) pectoral girdle were generated by systematic changes in the factors that potentially influence the surface geometries. Twenty‐four landmarks were repeatedly acquired by different observers. The contribution of all factors to the total variance in the landmark data was assessed using random‐factor nested permanova s. Selected sets of Euclidean distances between landmark sets served further to compare the variance among factor levels. Landmark precision was assessed by landmark standard deviation and compared among observers and days. Results showed that all factors, except for voxel size, significantly contributed to measurement error in at least some of the analyses performed. In total, 6.75% of the variance in landmark data that mimicked a realistic biological study was caused by measurement error. In this landmark dataset, intra‐observer error was the major source of artefactual variance followed by inter‐observer error; the factor segmentation contributed 〈 1% and slight surface simplification had no significant effect. Inter‐observer error clearly exceeded intra‐observer error in a different landmark dataset acquired by six partly inexperienced observers. The results suggest that intra‐observer error can potentially be reduced by including a training period prior to the actual landmark acquisition task and by acquiring landmarks in as few sessions as possible. Additionally, the application of moderate and careful surface simplification and, potentially, also the use of case‐specific optimal combinations of automatic local thresholding algorithms and parameters for segmentation can help reduce intra‐observer error. If landmark data are to be acquired by several observers, it is important to ensure that all observers are consistent in landmark identification. Despite the significant amount of artefactual variance, we have shown that landmark data acquired from microCT ‐derived surfaces are precise enough to study the shape of anuran pectoral girdles. Yet, a systematic assessment of measurement error is advisable for all geometric morphometric studies.
    Materialart: Online-Ressource
    ISSN: 0021-8782 , 1469-7580
    URL: Issue
    Sprache: Englisch
    Verlag: Wiley
    Publikationsdatum: 2019
    ZDB Id: 1474856-3
    SSG: 12
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 5
    Online-Ressource
    Online-Ressource
    Wiley ; 2017
    In:  Journal of Anatomy Vol. 230, No. 4 ( 2017-04), p. 497-509
    In: Journal of Anatomy, Wiley, Vol. 230, No. 4 ( 2017-04), p. 497-509
    Kurzfassung: Scorpions have elongated metasomas that bear a telson, which is used as a stinger for venom injection. There is a remarkable diversity in the use of the stinger among scorpions, comprising defensive behavior, prey subjugation and mating. This diversity could be reflected by the shape of the telson, as different stinging behaviors will result in very different functional demands. Here we explored the diversity of telson shapes in scorpions by providing morphological measurements, such as curvature and tip angle, as well as by testing stingers under load using finite element analysis ( FEA ). FEA models were loaded with forces scaled to the surface area of the models, to allow comparison of the relative strain energy based on shape alone. Load force angle was rotated to identify the optimal stinging angle based on the lowest strain energy. Aculeus length and mean aculeus height correlated with minimal strain energy. Optimal stinging angle correlated with tip angle, and differed from the tip angle by about 28.4 ± 6.22 °. We found that species that are more venomous have long aculei (stinger barbs) with a larger radius of curvature. FEA models of these longer aculei showed basal stress concentrations, indicating a potential greater risk of basal breakage due to shape alone. Telsons with shorter and thicker aculeus shapes showed stress concentrations at the tip only. Despite these marked differences in shape, we found no difference in the scaled strain energy between groups of species that are more venomous and less venomous groups of species. These results show that scorpion stingers may be biomechanically optimized, and this may indicate different usage of the stinger in different species.
    Materialart: Online-Ressource
    ISSN: 0021-8782 , 1469-7580
    URL: Issue
    Sprache: Englisch
    Verlag: Wiley
    Publikationsdatum: 2017
    ZDB Id: 1474856-3
    SSG: 12
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 6
    Online-Ressource
    Online-Ressource
    Springer Science and Business Media LLC ; 2017
    In:  Artificial Life and Robotics Vol. 22, No. 4 ( 2017-12), p. 412-420
    In: Artificial Life and Robotics, Springer Science and Business Media LLC, Vol. 22, No. 4 ( 2017-12), p. 412-420
    Materialart: Online-Ressource
    ISSN: 1433-5298 , 1614-7456
    Sprache: Englisch
    Verlag: Springer Science and Business Media LLC
    Publikationsdatum: 2017
    ZDB Id: 1480655-1
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 7
    Online-Ressource
    Online-Ressource
    Oxford University Press (OUP) ; 2017
    In:  Journal of Crustacean Biology Vol. 37, No. 2 ( 2017-03-01), p. 142-150
    In: Journal of Crustacean Biology, Oxford University Press (OUP), Vol. 37, No. 2 ( 2017-03-01), p. 142-150
    Materialart: Online-Ressource
    ISSN: 0278-0372 , 1937-240X
    RVK:
    Sprache: Englisch
    Verlag: Oxford University Press (OUP)
    Publikationsdatum: 2017
    ZDB Id: 2173764-2
    SSG: 12
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 8
    Online-Ressource
    Online-Ressource
    Beilstein Institut ; 2016
    In:  Beilstein Journal of Nanotechnology Vol. 7 ( 2016-06-22), p. 893-903
    In: Beilstein Journal of Nanotechnology, Beilstein Institut, Vol. 7 ( 2016-06-22), p. 893-903
    Kurzfassung: Frogs (Lissamphibia: Anura) use adhesive tongues to capture fast moving, elusive prey. For this, the tongues are moved quickly and adhere instantaneously to various prey surfaces. Recently, the functional morphology of frog tongues was discussed in context of their adhesive performance. It was suggested that the interaction between the tongue surface and the mucus coating is important for generating strong pull-off forces. However, despite the general notions about its importance for a successful contact with the prey, little is known about the surface structure of frog tongues. Previous studies focused almost exclusively on species within the Ranidae and Bufonidae, neglecting the wide diversity of frogs. Here we examined the tongue surface in nine different frog species, comprising eight different taxa, i.e., the Alytidae, Bombinatoridae, Megophryidae, Hylidae, Ceratophryidae, Ranidae, Bufonidae, and Dendrobatidae. In all species examined herein, we found fungiform and filiform papillae on the tongue surface. Further, we observed a high degree of variation among tongues in different frogs. These differences can be seen in the size and shape of the papillae, in the fine-structures on the papillae, as well as in the three-dimensional organization of subsurface tissues. Notably, the fine-structures on the filiform papillae in frogs comprise hair-like protrusions (Megophryidae and Ranidae), microridges (Bufonidae and Dendrobatidae), or can be irregularly shaped or absent as observed in the remaining taxa examined herein. Some of this variation might be related to different degrees of adhesive performance and may point to differences in the spectra of prey items between frog taxa.
    Materialart: Online-Ressource
    ISSN: 2190-4286
    Sprache: Englisch
    Verlag: Beilstein Institut
    Publikationsdatum: 2016
    ZDB Id: 2583584-1
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 9
    Online-Ressource
    Online-Ressource
    Springer Science and Business Media LLC ; 2016
    In:  Journal of Comparative Physiology A Vol. 202, No. 4 ( 2016-4), p. 267-276
    In: Journal of Comparative Physiology A, Springer Science and Business Media LLC, Vol. 202, No. 4 ( 2016-4), p. 267-276
    Materialart: Online-Ressource
    ISSN: 0340-7594 , 1432-1351
    RVK:
    Sprache: Englisch
    Verlag: Springer Science and Business Media LLC
    Publikationsdatum: 2016
    ZDB Id: 1459295-2
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 10
    Online-Ressource
    Online-Ressource
    The Royal Society ; 2018
    In:  Journal of The Royal Society Interface Vol. 15, No. 145 ( 2018-08), p. 20180396-
    In: Journal of The Royal Society Interface, The Royal Society, Vol. 15, No. 145 ( 2018-08), p. 20180396-
    Kurzfassung: Surfaces with re-entrant topographies can repel liquids even of extremely low surface tension, almost independently of the material's inherent wettability. We show that this topography-based wetting resistance can also be applied to underwater applications, reducing the permanent adhesion of marine hardfouling organisms. Having combined a biofouling assay in the marine environment with microscopic analyses, we demonstrate how a synergistic effect of a soft silicone-based material with a re-entrant mushroom-shaped surface topography strongly increases the fouling release ability of such coatings compared with a smooth control made from the same material. Our coating inhibited the complete wetting of the solidifying glues produced by marine organisms, which resulted in a decreased contact area and, consequently, low adhesion. Our work suggests that topography-induced wetting resistance of surfaces may become a viable approach in preventing permanent adhesion of marine hardfouling organisms.
    Materialart: Online-Ressource
    ISSN: 1742-5689 , 1742-5662
    Sprache: Englisch
    Verlag: The Royal Society
    Publikationsdatum: 2018
    ZDB Id: 2156283-0
    Standort Signatur Einschränkungen Verfügbarkeit
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