Modelling and manufacturing of a dragonfly wing as basis for bionic research

Working principles in nature have been optimised by evolution for millions of years. Today we try to understand how these principles work and how they could be used in technical applications. Prominent examples for solutions which are inspired by bionic research are the Velcro fastener (inspired by the plant \u27Arcticum lappa\u27) [Pahl et al., 2003], swim suits (inspired by shark skin) [Thilmany, 2004] and self-cleaning surfaces using the lotus effect [von Baeyer, 2000]. The topic of aerodynamics is another large area for research and innovation in which we still hope to be able to learn from nature. The dragonfly combines very light wing structures with amazing flying abilities [Okamoto, 1996]. In order to study the exact properties of the dragonfly wing and to understand how this properties can be achieved, it is necessary to reproduce the geometry of the wing at a larger scale. This large scale model can be used to conduct further aerodynamic tests in a wind tunnel. The results of such investigations can lead to new impulses for the development of aircraft and micro air vehicles. In this paper the authors will describe the modelling and building of an enlarged model of a dragonfly wing as base for further bionic research

Modelling and manufacturing of a dragonfly wing as basis for bionic research

Working principles in nature have been optimised by evolution for millions of years. Today we try to understand how these principles work and how they could be used in technical applications. Prominent examples for solutions which are inspired by bionic research are the Velcro fastener (inspired by the plant 'Arcticum lappa') [Pahl et al., 2003], swim suits (inspired by shark skin) [Thilmany, 2004] and self-cleaning surfaces using the lotus effect [von Baeyer, 2000]. The topic of aerodynamics is another large area for research and innovation in which we still hope to be able to learn from nature. The dragonfly combines very light wing structures with amazing flying abilities [Okamoto, 1996]. In order to study the exact properties of the dragonfly wing and to understand how this properties can be achieved, it is necessary to reproduce the geometry of the wing at a larger scale. This large scale model can be used to conduct further aerodynamic tests in a wind tunnel. The results of such investigations can lead to new impulses for the development of aircraft and micro air vehicles. In this paper the authors will describe the modelling and building of an enlarged model of a dragonfly wing as base for further bionic research

Definition of the interacting interfaces of Apobec3G and HIV-1 Vif using MAPPIT mutagenesis analysis

The host restriction factor Apobec3G is a cytidine deaminase that incorporates into HIV-1 virions and interferes with viral replication. The HIV-1 accessory protein Vif subverts Apobec3G by targeting it for proteasomal degradation. We propose a model in which Apobec3G N-terminal domains symmetrically interact via a head-to-head interface containing residues 122 RLYYFW 127. To validate this model and to characterize the Apobec3G–Apobec3G and the Apobec3G–Vif interactions, the mammalian protein–protein interaction trap two-hybrid technique was used. Mutations in the head-to-head interface abrogate the Apobec3G–Apobec3G interaction. All mutations that inhibit Apobec3G–Apobec3G binding also inhibit the Apobec3G–Vif interaction, indicating that the head-to head interface plays an important role in the interaction with Vif. Only the D128K, P129A and T32Q mutations specifically affect the Apobec3G–Vif association. In our model, D128, P129 and T32 cluster at the edge of the head-to-head interface, possibly forming a Vif binding site composed of two Apobec3G molecules. We propose that Vif either binds at the Apobec3G head-to-head interface or associates with an RNA-stabilized Apobec3G oligomer

Strength of Social Tie Predicts Cooperative Investment in a Human Social Network

Social networks – diagrams which reflect the social structure of animal groups – are increasingly viewed as useful tools in behavioural ecology and evolutionary biology. Network structure may be especially relevant to the study of cooperation, because the action of mechanisms which affect the cost:benefit ratio of cooperating (e.g. reciprocity, punishment, image scoring) is likely to be mediated by the relative position of actor and recipient in the network. Social proximity could thus affect cooperation in a similar manner to biological relatedness. To test this hypothesis, we recruited members of a real-world social group and used a questionnaire to reveal their network. Participants were asked to endure physical discomfort in order to earn money for themselves and other group members, allowing us to explore relationships between willingness to suffer a cost on another's behalf and the relative social position of donor and recipient. Cost endured was positively correlated with the strength of the social tie between donor and recipient. Further, donors suffered greater costs when a relationship was reciprocated. Interestingly, participants regularly suffered greater discomfort for very close peers than for themselves. Our results provide new insight into the effect of social structure on the direct benefits of cooperation