N = 1 supergravity in the light-cone gauge

N = 1 supergravity is studied in a light-cone gauge. The non-linear transformations and the hamiltonian are constructed to order K in the coupling constant as a realization of the super-Poicaré algebra. The only input except the algebraic structure is the helicity content ($\text{±2, ±}\text{3}\text{2}$) and the dimensionality of the coupling constant.     

Synthese stereoisomerer Pinanthromboxane und Evaluation der Verbindungen als Plättchenaggregationsinhibitoren

Synthesis of Stereisomeric Pinanthromboxane Derivatives and Evaluation of the Compounds as Platelet Aggregation Inhibitors Starting from the two enantiomeric myrtenols ((?)- 1 and (+)- 1 ; cf. Scheme 1), the synthesis of twelve stereoisomeric pinanthromboxane derivatives ((+)- and (?)- 10, -11, -14, -15, -21 and -22 ) is described (cf. Schemes 1–4). Biological data from the evaluation as platelet aggregation inhibitors (cf. Table 6 and 7), thromboxane synthetase inhibitors (cf. Table 8) and from the assessment as antagonists of leukotriene E₄ induced bronchoconstriction (cf. Table 9) are presented.     

SiO2 surface defect centers studied by AES

A theoretical model is proposed on how a Si dangling bond associated with an oxygen vacancy on a SiO₂ surface (E_s′ center) should be observed by Auger electron spectroscopy (AES). The Auger electron distribution N_A(E) for the L₂₃VV transition band is calculated for a stoichiometric SiO₂ surface, and for a SiO_x surface containing Si-(e^?O₃) coordinations. The latter is characterized by an additional L₂₃VD transition band, where D is the energy level of the unpaired electron e^?. The theoretical N_A(E) spectra are compared with experimental N(E) spectra for a pristine, and for an electron radiation damaged quartz surface. Agreement with the theoretical model is obtained if D is assumed to lie ≈2 eV below the conduction band edge. This result shows that AES is uniquely useful in revealing the absolute energy level of localized, occupied surface defect states. As the L₂₃VD transition band (main peak at 86 eV) cannot unambiguously be distinguished from a SiSi₄ coordination L₂₃VV spectrum (main peak at 88 eV), supporting evidence is presented as to why we exclude a SiSi₄ coordination for our particular experimental example. Application of the Si-(e^?O₃) model to the interpretation of SiO₂Si interface Auger spectra is also discussed.     

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