The present state of the art of theoretical studies of magnetism in artificial low dimensional transition metal materials, e.g., surfaces, overlayers and multilayers, is reviewed here by means of some illustrative examples. Strong magnetic moment enhancements are found for Fe, Co and Ni atoms at surfaces or interfaces contacting with inert substrates. By contrast, the spin polarization is stron...

A mean field model of ferromagnetism mediated by delocalized or weakly localized holes in zincblende and wurzite diluted magnetic semiconductors is presented. The model takes into account: (i) strong spin-orbit and kp couplings in the valence band; (ii) the effect of strain upon the hole density-of-states, and (iii) the influence of disorder and carrier-carrier interactions, particularly near t...

Four new lignans, 3',4'-O,O-demethylenehinokinin (1), chamalignolide (2), 8'beta-hydroxyhinokinin (3) and 7beta,8beta-epoxyzuonin A (4), as well as (-)-hinokinin (5), and (-)-zuonin A (6), were isolated from the heartwood of Chamaecyparis obtusa var. formosana. The structures of these lignans were unambiguously determined by spectroscopic methods. And the absolute configuration of 1 was elucida...

Decandrinin (1), an unprecedented C9-spiro-fused 7,8-seco-ent-abietane, was obtained from the bark of an Indian mangrove, Ceriops decandra, collected in the estuary of Godavari, Andhra Pradesh. The constitution and the relative configuration of 1 were determined by HRMS (ESI) and extensive NMR investigations, and the absolute configuration by circular dichroism (CD) and optical-rotatory dispers...

The question how proteins fold into their specific three-dimentional structures provides anexciting challenge for biophysicists nowadays. The use of a fast temperature-jump is a verypowerful technique for the study of the denaturation process of proteins. However, probingthe secondary structure is a difficult challenge and rarely yields quantitative values. The main purpose of this ...

Negative real parts of the permittivity and permeability lead an isotropic chiral medium to exhibit circular dichroism that is reversed with respect to that exhibited by an identical medium but the real parts of whose permittivity and permeability are positive.