Heteroatom transfer to alkenes by N-protected-oxaziridines: new reaction pathways and products

N-Alkoxycarbonyl- and N-carboxamido-oxaziridines are shown to react with aromatic alkenes to give epoxide, aziridine or hydro-oxidation products, in ratios depending on the oxaziridine structure. Chiral oxaziridines can effect epoxidation and hydro-oxidation with promising levels of asymmetric induction.     

A deuterium nuclear quadrupole double resonance study of the ferroelectric phase transition in potassium dihydrogen phosphate

A study has been made of the nuclear quadrupole double resonance (NQDR) spectrum of deuterium in a powdered sample of potassium dihydrogen phosphate, KH₂PO₄ or KDP for short, both as a function of temperature and of percentage deuteration. Double transitions have also been observed and these enable the orientation of the ferroelectric electric field gradient (EFG) tensor to be determined.     

Electroanalytical applications of carbon fibre electrodes

The analytical uses of carbon fibre electrodes cover such diverse areas as coulometry, potentiometry, anodic stripping voltammetry, potentiometric stripping voltammetry, spectroelectrochemistry and kinetic measurements. The electrodes have been employed in a variety of cell types and locations, including conventional two and three electrode cells, flowing streams and in-vivo. The electroanalytical applications and theory are discussed in this review, along with the structure and surface properties of carbon fibres. Specialist instrumentation is also described.     

An elegant but “simple” form for the Dirac hydrogen atom

The operator structures for the constants of the motion of the relativistic hydrogen atom are examined. ThoughJ ³ andJ · J are constants of the motion,J is not. Its replacement, , is shown to emerge rather naturally in transforming the equation to spherical coordinates. The separation of variables is presented in hypercomplex number form. This leads to some interesting suggestions regarding the matter/antimatter operator for the Dirac equation.     

Studies on the adsorption of nitrogen dioxide onto manganese dioxide-coated quartz piezoelectric crystals

A technique for obtaining thin; evenly distributed manganese dioxide coatings by melting manganese nitrate is outlined. Responses of an AT-cut quartz piezoelectric crystal coated with manganese dioxide to nitrogen dioxide (12.5-10 000 μl 1^?1) over a range of humidities (400–4,800 μ1 l^?1 water) and temperatures (20–35 °C) are given. The response of the simulated product manganese nitrate, over the same range of humidities, is evaluated in relationship to real product formation. The approach may be applicable to other metal salt/metal oxide systems. The detection limit is 7 μl^?1 nitrogen dioxide.     

DETECTION OF DNA-PSORALEN PHOTOADDUCTS in situ

Abstract— An immunological method, with the use of specific immune serum, has been developed for detection of 8-methoxypsoralen (8-MOP) photoadducts to DNA, formed in situ in cell nuclei, after combined treatment with 8MOP and UV-A irradiation (Zarçbska et al. , 1978). Lymphocytes fixed on slides or in suspension, and cryostat sections of different mammalian tissues, served as antigenic substrate, after treatment with 8-MOP and UV-A in vitro. Specific fluorescence in these substrates was detected in the nuclei after treatment with 30 ˜ 140 kJ/m² UV-A in the presence of 0.1-0.3 μg/cm² 8-MOP. PHA-stimulated-lymphocytes appeared to be the most sensitive substrate.
However, hairless mice treated with high doses of UV-A in vivo , 70 ˜ 360 kJ/m² did not reveal a specific fluorescence of epidermal nuclei, unless a high local concentration of 8-MOP was attained.
The apparent discrepancy in the level of photoadduct detection between the in vitro and in vivo treated specimens was explained by the low number of DNA-8-MOP-photoadducts formed in vivo under these experimental conditions. The relevance of these findings to the role of DNA-8-MOP-photoadducts formed during PUVA photochemotherapy is discussed.     

Simplification and analysis of a model of social interaction in voting

A recently proposed model of social interaction in voting is investigated by simplifyingit down into a version that is more analytically tractable and which allows a mathematicalanalysis to be performed. This analysis clarifies the interplay of the different elementspresent in the system – social influence, heterogeneity and noise – and leads to a betterunderstanding of its properties. The origin of a regime of bistability is identified. Theinsight gained in this way gives further intuition into the behaviour of the originalmodel.     

Generalized charge in the eight-component spin-1/2 wave equation

A conserved current is given for the hypermass generalization of the Dirac equation. The generalization of charge to an invariant quaternion is given which provides insight into a new vector space for relativistic quantum theory. This charge generalization also ensures the independence of the eight internal degrees of freedom in the wave equation.