In South-eastern England, north of the River Thames, is a small but important group of rich La Tène III cremation burials (fig. 1). One of the characteristics of the group is the absence of a mound, or any other surface indication, and it follows from this that the discoveries are invariably by chance, as a result of some agricultural or commercial excavation. At best the archaeologist has had to make a hasty excavation under conditions far from ideal, and at worst he has been presented with a garbled account of the discovery and an incomplete collection of grave-goods.
Pseudo-polyrotaxanes (PPRs) are supramolecular host-guest complexes constituted by the reversible threading of a macrocycle along a polymer chain, which offers potential applications in nanotechnology, drug delivery and biomaterials. We report the threading of cyclodextrins (CDs), cyclic oligosaccharides, onto X-shaped PEO-PPO block-copolymers, with two opposite presentation of their hydrophobic and hydrophilic blocks: Tetronic 904 (T904), and its reverse counterpart, Tetronic T90R4. We assess the effect of relative block position on the polymeric surfactants and cavity size of CD have on the composition, morphology, thermodynamics and kinetics of PPRs by using a combination of X-ray diffraction, Scanning Electron Microscopy (SEM), NMR, UV-Vis spectroscopy and Time-Resolved Small-Angle Neutron Scattering (TR-SANS). Solid PPRs with lamellar microstructure and crystalline channel-like structures are obtained with native CDs and both Tetronics above a threshold concentration of the macrocycle, which varies with the type of CD and surfactant. While γ-CD can form PPRs with both Tetronics, α-CD only form a PPR with T90R4 at high concentrations. The results can be explained in terms of the preferential complexation of α-CD with EO and γ-CD with PO monomers, which also has a direct impact on the kinetics of PPR formation. Thermodynamic parameters of the reaction were obtained from the analysis of the stoichiometries and threading times as a function of temperature by using a model based on the Eyring equation. Negative enthalpies and positive entropies are obtained in all cases, and reactions are thermodynamically most favorable in the case of α-CD with T904 and γ-CD with T90R4. TR-SANS experiments reveal an increase in the radius of gyration of the unimers over time, consistent with CDthreading and expansion of the PPR. Above the CMT, α-CD threads the unimers to form the PPR, with no effect on the structure of T904 micelles, whose volume fraction decreases due to the shift of micellization equilibrium.
New finds of astonishing splendour have come to light at Snettisham (Norfolk, England), a place which already holds a special, if enigmatic, place in Iron Age studies. Discoveries there first put British gold torques on the map; the magnificent great torque not only gave its name to an art-style but held a coin that helped to date it, and the very wealth of the place has provoked endless speculation.
A small chalk figurine from Withemsea, North Humberside, is identified as the finest example of a distinctive group found only in the territory of the Parisi. Between forty and fifty figurines are now known and many represent a warrior, usually carrying a sword on his back. Most of the figurines come from Iron Age or Roman sites, and all the swords are shown in scabbards suspended about their midpoint—a fashion known in northern Britain in the Iron Age. The warrior represented is presumably a god, mythical figure or ancestor, and the figurines may well have had a ritual or magical function.
The Iron Age hill-fort at Grimthorpe (Grid reference SE.816535) in the parish of Millington, East Riding of Yorkshire, is on the western edge of the Yorkshire Wolds, with a commanding position over the Vale of York. There is an uninterrupted view to the White Horse on the Hambleton Hills, 25 miles to the north-west; beyond York, 13 miles to the west, to the Pennines; and to the south 25 miles to the chimneys of Keadby and Scunthorpe. To the west and south the land slopes away to the Vale of York, and to the north and east there is a sharper fall to Given Dale and Whitekeld Dale. The hill-fort defences follow the 520 feet contour, and enclose an approximately circular area of eight acres (fig. 1).A traditional reference may be preserved in the field-name—Bruffs—perhaps a variation of ‘Brough’, which ‘refers in all cases to ancient camps, usually Roman ones’. But all surface indications have now been obliterated by ploughing, and even a century ago there was little more to be seen. John Phillips in 1853 noticed ‘unmistakable traces of ancient but unascertainable occupation’, and in 1871 an excavation by J. R. Mortimer located ‘the filled up inner ditch of a supposed camp’. But Mortimer was not concerned with the settlement; his interest had been aroused by the discovery, in 1868, of a burial with rich grave-goods, including metalwork with La Tène ornament, in a chalk-pit within the south-west sector of the hill-fort.
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