Research articles

In human societies, altruistic behaviour can evolve because those who fail to co-operate are lumbered with a bad reputation. This study explores the circumstances under which punishment is favoured using a game theory model in which all individuals observe the interactions between others and assess their reputation under various social norms. It is shown that punishment is only a successful strategy under a narrow set of parameters, including the relative costs of punishment and cooperation, the reliability of reputations and the spread of gossip.

This study models converted teleseismic waves to constrain the seismological properties of subducted oceanic crust from the Cascadia continental margin to its intersection with the forearc mantle. The observations suggest that water is pervasively present in fluid form at high pore pressures, indicating that the megathrust is a low-permeability boundary. These results may hold important implications for our understanding of seismogenesis, subduction-zone structure and the mechanism of episodic tremor and slip.

Self-gravity plays a decisive role in the final stages of star formation, where dense cores inside molecular clouds collapse to form star-plus-disk systems. But the role of self-gravity at earlier times is unclear. This paper reports a dendogram analysis that reveals that self-gravity plays a significant role over the full range of scales traced by ¹³CO observations in L1448, but not everywhere in the observed region.

Lung carcinoma cells were found to secrete the extracellular matrix proteoglycan versican. Versican directly activates the TLR2 receptor complex on macrophages, which in turn promotes tumour metastasis by producing TNF-?. Thus cancer cells utilize signalling pathways of the innate immune system to support metastatic spread.

This study presents the structure of gp23-chaperonin complexes showing gp23 encapsulated in the folding chamber. The folding chamber is distorted to enclose a large substrate, and this is the first study that visualizes of a newly folded physiological substrate trapped inside the folding chamber of GroEL.

This paper describes the combination of near-field optical forces (such as those used in optical traps) to confine nanoscopic matter inside a liquid core-slot waveguide and photon scattering forces to transport them. The waveguide overcomes the diffraction limits of conventional optical trapping systems to manipulate objects down to tens of nanometres in scale. As the waveguide is linear, it can also manipulate extended biomolecules demonstrated by trapping and transporting DNA molecules.

After expression of the PML–RAR oncogene in haematopoietic stem cells, p21 is necessary to limit cell cycle progression and thus limit the accumulation of DNA damage which would otherwise limit the self-renewal of leukaemic stem cells and prevent the development of leukaemia