Current limits on the cold dark matter interaction cross section obtained by the UK collaboration

The UK Dark Matter Collaboration has run a 5–6 kg NaI detector in a well-shielded underground environment for about a year. Signatures of Cold Dark Matter (CDM) interactions are sought using pulse shape discrimination techniques by searching for the relatively short scintillation pulses arising from nuclear recoils among the residual, longer, background events from residual radioactivity in the detector and its environment. Here we report on an improvement to the limits on the CDM cross section for spin dependent interactions using our latest data from a crystal with improved detection efficiency and taking into account recent improved estimates of the spin factor correction between the nucleus and nucleon-supersymmetric particle cross sections.     

Studies on the reaction of primary and secondary amines with phenylseleninic anhydride and with phenylseleninic acid

The dehydrogenation under mild conditions of indolines with phenylseleninic anhydride or acid affords good yields of indoles or of 3-phenylselenenyl indoles. Tetrahydroquinoline and -isoquinoline show comparable behaviour. The dehydrogenation of primary amines gives more complicated mixtures from which nitriles and bis-2-phenylselenenylaldehydes can be isolated.     

Preparation of aldehydes and ketones by oxidation of benzylic hydrocarbons with benzeneseleninic anhydride

Benzeneseleninic anhydride is a mild oxidant for the conversion of benzylic hydrocarbons into aldehydes or ketones.     

The absorption spectrum of polycrystalline silver halide fibres

The wavelength dependence of the attenuation in polycrystalline AgCl:AgBr fibre has been determined between 2.5 μm and 14 μm. The background attenuation as λ^-2 dependence as expected but there are also strong absorption peaks due to water and silver oxide which, to our knowledge, are observed for the first time in these fibres.     

Defect location clustering schemes

Algorithms for clustering n objects typically require O(n²) operations. This report presents a special approach for a certain class of data that requires O(n) operations and O(n) storage. Such data commonly occur when a microscopic signal structure is imposed on a medium with potential for macroscopic defects, and the signal elements are then checked sequentially for error. The algorithm can be used to cluster other classes of data in O(n log n) operations. An application to videodisc defect consolidation is presented.     

Application of orthogonal signal correction to minimise the effects of physical and biological variation in high resolution 1H NMR spectra of biofluids

1H nuclear magnetic resonance (NMR)-based metabonomics is a well-established technique used to analyse and interpret complex multiparametric metabolic data, and has a wide number of applications in the development of pharmaceuticals. However, interpretation of biological data can be confounded by extraneous variation in the data such as fluctuations in either experimental conditions or in physiological status. Here we have shown the novel application of a data filtering method, orthogonal signal correction (OSC), to biofluid NMR data to minimise the influence of inter- and intra-spectrometer variation during data acquisition, and also to minimise innate physiological variation. The removal of orthogonal variation exposed features of interest in the NMR data and facilitated interpretation of the derived multivariate models. Furthermore, analysis of the orthogonal variation provided an explanation of the systematic analytical/biological changes responsible for confounding the original NMR data.     

The invention of new radical chain reactions. Part VIII. Radical chemistry of thiohydroxamic esters; A new method for the generation of carbon radicals from carboxylic acids

The aliphatic and alicyclic esters of N-hydroxypyridine-2-thione are readily reduced by tributylstannane in a radical chain reaction to furnish nor-alkanes.¹ In the absence of the stannane a smooth decarboxylatlive rearrangement occurs to give 2-substituted thiopyridines.¹ The radicals present in this reaction provoke with $\text{t}$-butylthiol an efficient radical reaction with formation of nor-alkane and 2-pyridyl-$\text{t}$-butyl disulphide.¹Similarly these carbon radicals can be captured by halogen atom transfer to give noralkyl chlorides, bromides and iodides. 2 With oxygen in the presence of t-butylthiol the corresponding noralkyl hydroperoxides are formed in another radical chain reaction.³