On the topological characterization of two-dimensional phase transitions

It is shown that for the two-dimensional planar-rotator model the variance of the number of vortices inside a large loop is proportional to the perimeter of the loop at all temperatures. A similar result holds for the variance of the charge inside a loop in the lattice Coulomb gas model. Hence a topological distinction between the high and low temperature phases of these models (area law versus perimeter law) is not possible.     

Equivalence of degeneracy regularizations of lattice fermions

It is shown that the recently proposed degeneracy regularization of Becher for free fermions on a lattice is completely equivalent to that of Susskind.     

Study of combined electroreflectance and double layer effects at lead electrodes

Reflectance changes at lead electrodes have been measured as a function of surface charge at 45° and 70° angles of incidence using solutions of sodium fluoride and quaternary ammonium salts. These solutions were chosen so as to provide quite different composition for the inner layer at the metal/solution interface, and hence different optical contributions there from. Linear reflectance-surface charge relation has been observed for NaF solutions only at a number of wavelengths. The optical effects from the inner layer has been recognized but could not be separated out from the main er effect by comparative measurements at two angles of incidence. This has been rationalized on the basis of similar variation of the er effect and the optical effect from the double-layer as a function of angle of incidence of light.     

Polarography of niobium : Reduction in mineral acid media

The formation and interconversion of the nitro-, chloro-, perchloro- and sulphato-complexes of niobium in mineral acid media and the reduction of the nitro-complex have been studied. Conditions for a linear proportionality between the limiting current and the concentration of niobium in the microgram range have been worked out.     

SYNTHESIS AND PHOTOSENSITIZING ACTIVITY OF A DI-PORPHYRIN ETHER

Abstract A simple, well characterized porphyrin dimer with ether linkage was synthesized from 2- (1-hydroxyethyl)deuteroporphyrin dimethyl ester and found to be an effective in vivo photosensitizer in the murine SMT-F tumor system. The structure of the pure dimer was confirmed by NMR and mass spectroscopy.     

151Eu Mössbauer studies in the high Tc superconducting oxide materials

¹⁵¹Eu Mössbauer studies have been made across the respective superconductive transition temperatures in two compounds, La_1.7Eu_0.1Sr_0.2CuO_4?y and EuBa₂Cu₃O₇, having zero resistance state at 25K and 85K respectively. The¹⁵¹Eu isomer shift data establish that Eu ions are in trivalent state at all temperatures. The Mössbauer f-factor does not show any significant anomaly across the T_C.     

On cardioactive steroids. Communication XV. A stereoselective synthesis of (21R)-21-methyldigitoxigenin,a fully active cardenolide with a wide margin of safety: A contribution to the topology of the Digitalis receptors

Two efficient preparations of the title compound, one from common C₁₉-steroids, the other frm digitoxigenin, are described. The less active minor epimer (21S)-methyldigitoxigenin was also obtained and characterized. The positive inotropic effects and margins of safety of the two C(21)-epimers (tested as glucosides) are discussed in terms of the topological properties of the Digitalis receptors.     

Gamma and π0 production by 4 GeV/cπ+p interactions

Inclusive data for the production of γ rays and π⁰ are presented from an experiment with a 4 GeV/cπ⁺ beam, using a track-sensitive target. The results are compared with data at other energies and with π⁺and π^? distributions.     

Are there low-lying,intrashell-excited,highly deformed states in the 1f-2p shell nuclei?

It is shown that the improved effective interactions in the fp shell imply the existence of an excited band of states which is much more deformed than the ground state band for some fp shell nuclei. Such states are to a certain extent analogous to the fission isomers occurring in heavy nuclei. Their experimental identification would be interesting and might also help to further improve the effective interaction.