scholarly journals Fibrillar adhesion with no clusterisation: Functional significance of material gradient along adhesive setae of insects

2014 ◽  
Vol 5 ◽  
pp. 837-845 ◽  
Author(s):  
Stanislav N Gorb ◽  
Alexander E Filippov
Keyword(s):  
Numerical Experiment ◽  
Material Properties ◽  
Crucial Role ◽  
Functional Significance ◽  
Rough Surfaces ◽  
Adhesive System ◽  
Evolutionary Optimization ◽  
Fibrillar Adhesion

It has been recently demonstrated that adhesive tarsal setae of beetles possess material gradients along their length. These gradients presumably represent an evolutionary optimization enhancing the adaptation to rough surfaces while simultaneously preventing clusterisation of the setae by lateral collapse. The numerical experiment of the present study has clearly demonstrated that gradient-bearing fibers with short soft tips and stiff bases have greater advantage in maximizing adhesion and minimizing clusterisation in multiple attachment–detachment cycles, if compared to the fibers with longer soft tips on the stiff bases and fibers with stiff tips on the soft bases. This study not only manifests the crucial role of gradients in material properties along the setae in beetle fibrillar adhesive system, but predicts that similar gradients must have been convergently evolved in various lineages of arthropods.

scholarly journals Electrophysiological signatures of memory reactivation in humans

2020 ◽  
Vol 375 (1799) ◽  
pp. 20190293 ◽  
Author(s):  
Thomas Schreiner ◽  
Tobias Staudigl
Keyword(s):  
Episodic Memory ◽  
Neural Activity ◽  
Crucial Role ◽  
Memory Retrieval ◽  
Functional Significance ◽  
State Of The Art ◽  
Memory Reactivation ◽  
Open Questions ◽  
Neural Processes

The reactivation of neural activity that was present during the encoding of an event is assumed to be essential for human episodic memory retrieval and the consolidation of memories during sleep. Pioneering animal work has already established a crucial role of memory reactivation to prepare and guide behaviour. Research in humans is now delineating the neural processes involved in memory reactivation during both wakefulness and sleep as well as their functional significance. Focusing on the electrophysiological signatures of memory reactivation in humans during both memory retrieval and sleep-related consolidation, this review provides an overview of the state of the art in the field. We outline recent advances, methodological developments and open questions and specifically highlight commonalities and differences in the neuronal signatures of memory reactivation during the states of wakefulness and sleep. This article is part of the Theo Murphy meeting issue ‘Memory reactivation: replaying events past, present and future’.

scholarly journals Simulation of synthetic gecko arrays shearing on rough surfaces

2014 ◽  
Vol 11 (95) ◽  
pp. 20140021 ◽  
Author(s):  
Andrew G. Gillies ◽  
Ronald S. Fearing
Keyword(s):  
Surface Roughness ◽  
Rough Surfaces ◽  
Adhesive System ◽  
Single Fibre ◽  
Order Of Magnitude ◽  
Synthetic Adhesives ◽  
Contact Models ◽  
Nanoscale Features ◽  
The Relationship

To better understand the role of surface roughness and tip geometry in the adhesion of gecko synthetic adhesives, a model is developed that attempts to uncover the relationship between surface feature size and the adhesive terminal feature shape. This model is the first to predict the adhesive behaviour of a plurality of hairs acting in shear on simulated rough surfaces using analytically derived contact models. The models showed that the nanoscale geometry of the tip shape alters the macroscale adhesion of the array of fibres by nearly an order of magnitude, and that on sinusoidal surfaces with amplitudes much larger than the nanoscale features, spatula-shaped features can increase adhesive forces by 2.5 times on smooth surfaces and 10 times on rough surfaces. Interestingly, the summation of the fibres acting in concert shows behaviour much more complex that what could be predicted with the pull-off model of a single fibre. Both the Johnson–Kendall–Roberts and Kendall peel models can explain the experimentally observed frictional adhesion effect previously described in the literature. Similar to experimental results recently reported on the macroscale features of the gecko adhesive system, adhesion drops dramatically when surface roughness exceeds the size and spacing of the adhesive fibrillar features.

scholarly journals Hairy suckers: the surface microstructure and its possible functional significance in the Octopus vulgaris sucker

2014 ◽  
Vol 5 ◽  
pp. 561-565 ◽  
Author(s):  
Francesca Tramacere ◽  
Esther Appel ◽  
Barbara Mazzolai ◽  
Stanislav N Gorb
Keyword(s):  
Functional Significance ◽  
Smooth Surface ◽  
Rough Surfaces ◽  
Surface Structures ◽  
Surface Microstructure ◽  
Octopus Vulgaris ◽  
Dense Network ◽  
Sealing Mechanism ◽  
Suction Cups

Octopus suckers are able to attach to any smooth surface and many rough surfaces. Here, we have discovered that the sucker surface, which has been hypothesised to be responsible for sealing the orifice during adhesion, is not smooth as previously assumed, but is completely covered by a dense network of hair-like micro-outgrowths. This finding is particularly important because it provides another demonstration of the role of hair-structures in a sealing mechanism in water, similar to that previously described for clingfish and abalones. Moreover, the discovered hairs may provide an additional adhesive mechanism that works in concert with suction. The discovered surface structures might be potentially interesting for biomimetics of novel technical suction cups with improved adhesion capabilities on non-smooth surfaces.

Epitaxial YBa2Cu3O7-8 films : Crucial role of growth-induced linear defects in microwave properties

2001 ◽  
Vol 11 (PR11) ◽  
pp. Pr11-47-Pr11-52
Author(s):  
V. M. Pan ◽  
V. S. Flis ◽  
V. A. Komashko ◽  
O. G. Plys ◽  
C. G. Tretiatchenko ◽  
...  
Keyword(s):  
Crucial Role ◽  
Microwave Properties ◽  
Linear Defects

ANALISIS YURIDIS PUTUSAN PENGADILAN NEGERI BLORA TENTANG DUALISME KEPENGURUSAN YAYASAN PENDIDIKAN ISLAM KARTAYUDA YANG AKTA PENDIRIANNYA DIBUAT OLEH DAN DIHADAPAN NOTARIS (Studi Kasus Putusan Perkara PN Blora No. 34/Pdt.G/2015/PN.Bla)

Jurnal Akta ◽  
2017 ◽  
Vol 4 (3) ◽  
pp. 463
Author(s):  
Muslim Ansori ◽  
Akhmad Khisni
Keyword(s):  
Private Schools ◽  
Education System ◽  
Crucial Role ◽  
The State ◽  
Educational Institutions ◽  
Legal Entity ◽  
Non Profit ◽  
The Right

With the enactment of the Education System Act no 20 of 2003 (better known as the Sisdiknas Act), the State has determined that educational institutions should have a legal umbrella in the form of a legal entity, or better known as the Legal Entity Education. As a non-profit organization, the Foundation is the right legal entity that becomes a place for educational institutions, especially private schools. Therefore, of course, Notary has a very crucial role in making notary deed in the form of establishment and deed of change, such as example how in making the right basic budget and not multi interpresatasi for stake holders in the foundation. Therefore, the role of function and authority of the organ of the foundation must be clearly stated in the articles of association, so as not to cause a dispute in the future.KEYWORDS: Notaries, Foundation, Organ Foundation,

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