Thermo-Coulomb effects in mesoscopic tunnel junctions

We present a study of the thermoelectric effect in tunnel junctions. In particular we calculate the thermopower coefficientS and the Peltier coefficient . For macroscopic junctions we demonstrate the sensitivity ofS and to the structure of the density of states. For mesoscopic junctions we show that Coulomb effects modify the ordinary Onsager picture and the relation =TS. The coefficientsS and are found to be very sensitive to the coupling of the junctions to the external world. We analyze measurements of the thermopower in granular films in terms of the thermo-Coulomb effects. We comment on the relevance of these effects to scanning tunneling microscope measurements.     

PHOTODYNAMIC INACTIVATION OF YEAST SENSITIZED BY EOSIN Y

Abstract. Wild-type diploid yeast has been irradiated with visible light in the presence of eosin Y to investigate the photodynamic inactivation of this model eukaryote. Light, eosin Y and oxygen were all required for substantial inactivation, and no dark recovery was detected. Long periods of irradiation were required for greater than 90% inactivation, corresponding to a very small low-dose quantum yield. Neither binding nor uptake of the dye by yeast was detected. Corrections for the photooxidative bleaching of eosin Y during irradiation indicate that bleaching causes a significant reduction in the apparent rate of inactivation. The results suggest that eosin Y acts as an extracellular sensitizer where the likelihood of damage to the cell envelope is enhanced.     

The gauge in general relativity. III

A noncustomary gauge theory of general relativity, developed in detail in the preceding paper (II), is here applied to cosmology. A universe that is homogeneous and isotropic in the customary gauge, is considered-first generally, and then in more detail for the case where the noncustomary universe is matter dominated and static. With a particular choice of equation, this model is solved and a new relation between customary mass density, Hubble constant, and deceleration parameter is found. For a customary deceleration parameter of 1.98, this relation yields a customary mass density of 3.1×10^–31 g/cm³-in good agreement with experiment. Finally, the age of the universe in this model is found to be>6.6× 10⁹ yr, again in agreement with other estimates.     

Studies toward (-)-gymnodimine: concise routes to the spirocyclic and tetrahydrofuran moieties

[formula: see text] (-)-Gymnodimine is a member of a unique class of potent marine toxins possessing imines within a spirocylic array. Herein we report the synthesis of the tetrahydrofuran fragment and a strategy toward the spirocyclic imine fragment of this family of toxins. Key reactions include an asymmetric anti-aldol reaction to set the stereochemistry of the tetrahydrofuran and a formal, intermolecular Diels-Alder reaction involving an alpha-methylene-delta-lactam and a dienyne.     

The Number of Seymour Vertices in Random Tournaments and Digraphs

Seymour’s distance two conjecture states that in any digraph there exists a vertex (a “Seymour vertex”) that has at least as many neighbors at distance two as it does at distance one. We explore the validity of probabilistic statements along lines suggested by Seymour’s conjecture, proving that almost surely there are a “large” number of Seymour vertices in random tournaments and “even more” in general random digraphs.     

Selbstth?tige Auswaschvorrichtungen

Ohne Zusammenfassung