Using Nonlinear Response to Estimate the Strength of an Elastic Network

Disordered networks of fragile elastic elements have been proposed as a model of inner porous regions of large bones [Gunaratne et.al., cond-mat/0009221, http://xyz.lanl.gov]. It is shown that the ratio $\Gamma$ of responses of such a network to static and periodic strain can be used to estimate its ultimate (or breaking) stress. Since bone fracture in older adults results from the weakening of porous bone, we discuss the possibility of using $\Gamma$ as a non-invasive diagnostic of osteoporotic bone.Comment: 4 pages, 4 figure

Re-casting experience and risk along rocky coasts: A relational analysis using qualitative GIS

The information, practices and views in this article are those of the author(s) and do not necessarily reflect the opinion of the Royal Geographical Society (with IBG). © 2018 Royal Geographical Society (with the Institute of British Geographers). This study invites readers to experience risk on Australia’s hazardous rocky coasts with the rock fishing community. In the paper, we offer an understanding of risk that is relational, a process that emerges within human–environment interactions in a dynamic coastal space that is constantly changing. Exploring the in situ and ongoing sensory attunement of the fishers, we contend, expands upon the quantitative understandings that tend to be deployed by risk managers, offering an innovative approach to conceptualising risk. In identifying how fishers perceive and experience a rocky coastal location in Sydney, Australia, we track rock fishers’ movements using global positioning systems (GPS), undertake participant observation, and draw on video footage, semi-structured interviews and participatory sketch maps. In doing so, fishers’ perceptions of socio-environmental stimuli were spatially represented in a GIS, with sketch mapping being the proxy and/or the window into perception–environment relations that produce risk. We contend that the findings show that experienced fishers are more capable of anticipating and reacting to hazardous situations “safely” because they are more attuned to how changing coastal conditions affect risk. This study draws attention to the spatial and temporal phenomena that drive risk perceptions as well as the implications for future perception-oriented research that adopt a relational understanding

Coordination of Substrate Binding and ATP Hydrolysis in Vps4-Mediated ESCRT-III Disassembly

Vps4 disassembly of ESCRT-III plays an important role in MVB sorting, viral budding, and cytokinesis. An in vitro system was developed to investigate this process. These studies revealed new insights into the mechanisms of Vps4 function

Structural basis of TIR-domain-assembly formation in MAL- and MyD88-dependent TLR4 signaling

Toll-like receptor (TLR) signaling is a key innate immunity response to pathogens. Recruitment of signaling adapters such as MAL (TIRAP) and MyD88 to the TLRs requires Toll/interleukin-1 receptor (TIR)-domain interactions, which remain structurally elusive. Here we show that MAL TIR domains spontaneously and reversibly form filaments in vitro. They also form cofilaments with TLR4 TIR domains and induce formation of MyD88 assemblies. A 7-Å-resolution cryo-EM structure reveals a stable MAL protofilament consisting of two parallel strands of TIR-domain subunits in a BB-loop-mediated head-to-tail arrangement. Interface residues that are important for the interaction are conserved among different TIR domains. Although large filaments of TLR4, MAL or MyD88 are unlikely to form during cellular signaling, structure-guided mutagenesis, combined with in vivo interaction assays, demonstrated that the MAL interactions defined within the filament represent a template for a conserved mode of TIR-domain interaction involved in both TLR and interleukin-1 receptor signaling