Metal-non metal transitions in rare gas-metal systems

Pb-Xe and In-Ar mixtures at low temperatures are shown experimentally to undergo metal-non-metal transitions at about 60 and 33 at.% respectively of the metallic component. This observation is commented on in relation to metal-rare gas mixtures generally.     

Advances in microbiology to enhance oil recovery

Applied Biochemistry and Biotechnology - Microbial experiments to study enhanced oil recovery have generally been conducted using vegetative microorganisms and one-dimensional laboratory models....     

Equation of state and electrical resistivity of liquid mercury at elevated temperatures and pressures

Experimental results have been obtained for the density and electrical resistivity of liquid mercury as functions of the independent variables temperature (20°c–1000°c) and pressure (0–1000 bars). Basic equipment for both measurements consisted of a steel vessel containing an internal electrical resistance furnace and pressurized with argon gas. The equation of state was determined with an accuracy of about ±1/4% using Archimedes' method by employing a series of totally immersed radioactive sinkers whose rise or fall in the mercury was detected with a γ-ray counter external to the pressure vessel. The electrical resistivity was measured with an accuracy of about ±1/2% using a four-lead resistance cell fabricated in fused silica. The two measurements have also been combined to give electrical resistivity at constant volume.     

Influence of crystallographic orientation of biogenic calcite on in situ Mg XANES analyses

Micro X‐ray absorption near‐edge spectroscopy at the Mg K‐edge is a useful technique for acquiring information about the environment of Mg²⁺ in biogenic calcite. These analyses can be applied to shell powders or intact shell structures. The advantage of the latter is that the XANES analyses can be applied to specific areas, at high (e.g. micrometre) spatial resolution, to determine the environment of Mg²⁺ in a biomineral context. Such in situ synchrotron analysis has to take into account the potential effect of crystallographic orientation given the anisotropy of calcite crystals and the polarized nature of X‐rays. Brachiopod shells of species with different crystallographic orientations are used to assess this crystallographic effect on in situ synchrotron measurements at the Mg K‐edge. Results show that, owing to the anisotropy of calcite, in situ X‐ray absorption spectra (XAS) are influenced by the crystallographic orientation of calcite crystals with a subsequent potentially erroneous interpretation of Mg²⁺ data. Thus, this study demonstrates the importance of crystallography for XAS analyses and, therefore, the necessity to obtain crystallographic information at high spatial resolution prior to spectroscopic analysis.     

Modelling Aggregate-Level Entities as a Continuum

We have modelled the movement of groups of entities over realistic terrain using the equations of fluid dynamics. In our scheme, individual vehicles, people and even natural phenomena are modelled as localised packets of a fluid continuum that interact with a complex environment. The approach preserves the character of the individual and at the same time governs the long-range motion of the group. The scheme supports the co-ordination of large numbers of entities in a low-cost and plausible fashion. We provide details of how our technique has been exploited to represent the progress of crowds of people, and discuss in broad terms the scheme's general applicability to modelling aspects of Operations Other Than War (OOTW). We also demonstrate how established route planning techniques for single entities can be applied at the aggregate level, to guide the progress of groups of entities along roads and across open terrain.     

Rational design of novel neurotensin mimetics: Discovery of a pharmacologically unprecedented agent exhibiting concentration-dependent dual effects as antagonist and full agonist

Summary We report the rational design of novel neurotensin mimetics through use of the Multiple Template Approach. This approach is based on our notion that a flexible peptide can be replaced by a partially flexible molecule, identified through testing a comparatively small number of molecules possessing a different intrinsic availability of conformations of the native peptide. The Multiple Template Approach has culminated in the discovery of a pharmacologically unprecedented agent, which behaves as a neurotensin antagonist at low concentration and as a full neurotensin agonist at high concentration.     

Large sets of 3-designs from psl(2, q), with block sizes 4 and 5

We determine the distribution of 3?(q + 1,k,λ) designs, with k ? {4,5}, among the orbits of k-element subsets under the action of PSL(2,q), for q ? 3 (mod 4), on the projective line. As a consequence, we give necessary and sufficient conditions for the existence of a uniformly-PSL(2,q) large set of 3?(q + 1,k,λ) designs, with k ? {4,5} and q ≡ 3 (mod 4). © 1995 John Wiley & Sons, Inc.     

2,4,6-Tri-isopropylbenzenesulphonyl hydrazide: A convenient source of di-imide

2,4,6-Tri-isopropylbenzenesulphonyl hydrazide (TPSH, 3a) undergoes thermal decomposition in d₄-methanol solution at 35°, in the presence of triethylamine, at a rate ca. 380 times that of p-toluenesulphonyl hydrazide (2b). 3a has been found to be a convenient and effective hydrogenating agent for azobenzene and a number of olefins in methanol solution at 20° and in boiling ether and tetrahydrofuran solutions. Reductions in ether solution appear to be facilitated by the addition of base. 2,4,6-Trimethylbenzenesulphonyl hydrazide (MSH, 4a) undergoes thermal decomposition at a rate ca. 24 times that of 2b; 4a is also a useful hydrogenating agent.