Aurobindo Banerjee

© 2016 John Wiley & Sons Ltd.The motor of the membrane-anchored archaeal motility structure, the archaellum, contains FlaX, FlaI and FlaH. FlaX forms a 30nm ring structure that acts as a scaffold protein and was shown to interact with the bifunctional ATPase FlaI and FlaH. However, the structure and function of FlaH has been enigmatic. Here we present structural and functional analyses of isolated FlaH and archaellum motor subcomplexes. The FlaH crystal structure reveals a RecA/Rad51 family fold with an ATP bound on a conserved and exposed surface, which presumably forms an oligomerization interface. FlaH does not hydrolyze ATPin vitro, but ATP binding to FlaH is essential for its interaction with FlaI and for archaellum assembly. FlaH interacts with the C-terminus of FlaX, which was earlier shown to be essential for FlaX ring formation and to mediate interaction with FlaI. Electron microscopy reveals that FlaH assembles as a second ring inside the FlaX ring in vitro. Collectively these data reveal central structural mechanisms for FlaH interactions in mediating archaellar assembly: FlaH binding within the FlaX ring and nucleotide-regulated FlaH binding to FlaI form the archaellar basal body core.

© 2015 Macmillan Publishers Limited. All rights reserved.One of the primary goals of nuclear physics is to understand the force between nucleons, which is a necessary step for understanding the structure of nuclei and how nuclei interact with each other. Rutherford discovered the atomic nucleus in 1911, and the large body of knowledge about the nuclear force that has since been acquired was derived from studies made on nucleons or nuclei. Although antinuclei up to antihelium-4 have been discovered and their masses measured, little is known directly about the nuclear force between antinucleons. Here, we study antiproton pair correlations among data collected by the STAR experiment at the Relativistic Heavy Ion Collider, where gold ions are collided with a centre-of-mass energy of 200 gigaelectronvolts per nucleon pair. Antiprotons are abundantly produced in such collisions, thus making it feasible to study details of the antiproton-antiproton interaction. By applying a technique similar to Hanbury Brown and Twiss intensity interferometry, we show that the force between two antiprotons is attractive. In addition, we report two key parameters that characterize the corresponding strong interaction: the scattering length and the effective range of the interaction. Our measured parameters are consistent within errors with the corresponding values for proton-proton interactions. Our results provide direct information on the interaction between two antiprotons, one of the simplest systems of antinucleons, and so are fundamental to understanding the structure of more-complex antinuclei and their properties.

Objective: To explore the relationship between the presentation of suffering and support for euthanasia in the British news media.Method: Data was retrieved by searching the British newspaper database LexisNexis from 1996 to 2000. Twenty-nine articles covering three cases of family assisted suicide were found. Presentations of suffering were analysed employing Heidegger’s distinction between technological ordering and poetic revealing.Findings: With few exceptions, the press constructed the complex terrain of FAS as an orderly or orderable performance. This was enabled by containing the contradictions of FAS through a number of journalistic strategies: treating degenerative dying as an aberrant condition, smoothing over botched attempts, locating the object of ethical evaluation in persons, not contexts, abbreviating the decision making process, constructing community consensus and marginalising opposing views.Conclusion: The findings of this study support the view that news reporting of FAS is not neutral or inconsequential. In particular, those reports presenting FAS as an orderly, rational performance were biased in favor of technical solutions by way of the legalisation of euthanasia and/or the involvement of medical professionals. In contrast, while news reports sensitive to contradiction did not necessarily oppose euthanasia, they were less inclined to overtly support technical solutions, recognising the importance of a trial to address the complexity of FAS