Interaction of a poly(acrylic acid) oligomer with dimyristoylphosphatidylcholine bilayers

We studied the influence of 5 kDa poly(acrylic acid) (PAA) on the phase state, thermal properties, and lateral diffusion in bilayered systems of dimyristoylphosphatidylcholine (DMPC) using 31P NMR spectroscopy, differential scanning calorimetry (DSC), 1H NMR with a pulsed field gradient, and 1H nuclear Overhauser enhancement spectroscopy (NOESY). The presence of PAA does not change the lamellar structure of the system. 1H MAS NOESY cross-peaks observed for the interaction between lipid headgroups and polyion protons demonstrated only surface PAA-biomembrane interaction. Small concentrations of PAA (up to ∼4 mol %) lead to the appearance of a new lateral phase with a higher main transition temperature, a lower cooperativity, and a lower enthalpy of transition. Higher concentrations lead to the disappearance of measurable thermal effects. The lateral diffusion coefficient of DMPC and the apparent activation energy of diffusion gradually decreased at PAA concentrations up to around 4 mol %. The observed effects were explained by the formation of at least two types of PAA-DMPC lateral complexes as has been described earlier (Fujiwara, M.; Grubbs, R. H.; Baldeschwieler, J. D. J. Colloid Interface Sci., 1997, 185, 210). The first one is characterized by a stoichiometry of around 28 lipids per polymer, which corresponds to the adsorption of the entire PAA molecule onto the membrane. Lipid molecules of the complex are exchanged with the "pure" lipid bilayer, with the lifetime of the complex being less than 0.1 s. The second type of DMPC-PAA complex is characterized by a stoichiometry of 6 to 7 lipids per polymer and contains PAA molecules that are only partially adsorbed onto the membrane. A decrease in the DMPC diffusion coefficient and activation energy for diffusion in the presence of PAA was explained by the formation of a new cooperative unit for diffusion, which contains the PAA molecule and several molecules of lipids. © 2011 American Chemical Society

Miocene waterfowl and other birds from central Otago, New Zealand

Copyright © The Natural History Museum 2007Abundant fossil bird bones from the lower Bannockburn Formation, Manuherikia Group, an Early-Middle Miocene lacustrine deposit, 16–19 Ma, from Otago in New Zealand, reveal the “St Bathans Fauna” (new name), a first Tertiary avifauna of land and freshwater birds from New Zealand. At least 23 species of birds are represented by bones, and probable moa, Aves: Dinornithiformes, by eggshell. Anatids dominate the fauna with four genera and five species described as new: a sixth and largest anatid species is represented by just one bone. This is the most diverse Early-Middle Miocene duck fauna known worldwide. Among ducks, two species of dendrochenines are most numerous in the fauna, but a tadornine is common as well. A diving petrel (Pelecanoididae: Pelecanoides) is described, so extending the geological range of this genus worldwide from the Pliocene to the Middle Miocene, at least. The remaining 16 taxa are left undescribed but include: a large species of gull (Laridae); two small waders (Charadriiformes, genus indet.), the size of Charadrius bicinctus and Calidris ruficollis, respectively; a gruiform represented by one specimen similar to Aptornis; abundant rail (Rallidae) bones, including a common flightless rail and a rarer slightly larger taxon, about the size of Gallirallus philippensis; an ?eagle (Accipitridae); a pigeon (Columbidae); three parrots (Psittacidae); an owlet nightjar (Aegothelidae: Aegotheles sp.); a swiftlet (Apodidae: Collocalia sp.); and three passerine taxa, of which the largest is a member of the Cracticidae. The absence of some waterbirds, such as anserines (including swans), grebes (Podicipedidae) and shags (Phalacrocoracidae), among the abundant bones, indicates their probable absence from New Zealand in the Early-Middle Miocene.T. H. Worthy, A. J. D. Tennyson, C. Jones, J. A. McNamara and B. J. Dougla

Child Studies Multiple - Collaborative play for thinking through theories and methods

This is the final version. Available on open access from Linköpings University Electronic Press via the DOI in this recordThis text is an exploration of collaborative thinking and writing through theories, methods, and experiences on the topic of the child, children, and childhood. It is a collaborative written text (with 32 authors) that sprang out of the experimental workshop Child Studies Multiple. The workshop and this text are about daring to stay with mess, “un-closure” , and uncertainty in order to investigate the (e)motions and complexities of being either a child or a researcher. The theoretical and methodological processes presented here offer an opportunity to shake the ground on which individual researchers stand by raising questions about scientific inspiration, theoretical and methodological productivity, and thinking through focusing on process, play, and collaboration. The effect of this is a questioning of the singular academic ‘I’ by exploring and showing what a plural ‘I’ can look like. It is about what the multiplicity of voice can offer research in a highly individualistic time. The article allows the reader to follow and watch the unconventional trial-and-error path of the ongoing-ness of exploring theories and methods together as a research community via methods of drama, palimpsest, and fictionary

A technique for integrating remote minicomputers into a general computer's file system

This paper describes a simple technique for interfacing remote minicomputers used for real-time data acquisition into the file system of a central computer. Developed as part of the ORION system at CERN, this 'File Manager' subsystem enables a program in the minicomputer to access and manipulate files of any type as if they resided on a storage device attached to the minicomputer. Yet, completely transparent to the program, the files are accessed from disks on the central system via high-speed data links, with response times comparable to local storage devices. (6 refs)

ORION - the OMEGA Remote Interactive On-line System

ORION is a system which permits the manipulation of files, records and characters, remote job submittal and retrieval of output files including the direct loading of remote on-line computers. The system uses the computer hardware of the OMEGA project at CERN, and is designed to assist researchers in development and debugging of their programs