RESUMO
Superconductivity is among the most fascinating and well-studied quantum states of matter. Despite over 100 years of research, a detailed understanding of how features of the normal-state electronic structure determine superconducting properties has remained elusive. For instance, the ability to deterministically enhance the superconducting transition temperature by design, rather than by serendipity, has been a long sought-after goal in condensed matter physics and materials science, but achieving this objective may require new tools, techniques and approaches. Here, we report the transmutation of a normal metal into a superconductor through the application of epitaxial strain. We demonstrate that synthesizing RuO2 thin films on (110)-oriented TiO2 substrates enhances the density of states near the Fermi level, which stabilizes superconductivity under strain, and suggests that a promising strategy to create new transition-metal superconductors is to apply judiciously chosen anisotropic strains that redistribute carriers within the low-energy manifold of d orbitals.
RESUMO
The evolution of Sr2IrO4 upon carrier doping has been a subject of intense interest, due to its similarities to the parent cuprates, yet the intrinsic behaviour of Sr2IrO4 upon hole doping remains enigmatic. Here, we synthesize and investigate hole-doped Sr2-xKxIrO4 utilizing a combination of reactive oxide molecular-beam epitaxy, substitutional diffusion and in-situ angle-resolved photoemission spectroscopy. Upon hole doping, we observe the formation of a coherent, two-band Fermi surface, consisting of both hole pockets centred at (π, 0) and electron pockets centred at (π/2, π/2). In particular, the strong similarities between the Fermi surface topology and quasiparticle band structure of hole- and electron-doped Sr2IrO4 are striking given the different internal structure of doped electrons versus holes.
RESUMO
Eighteen male U.S. veterans meeting DSM-III criteria for posttraumatic stress disorder (PTSD) completed a 4-week double-blind, crossover study comparing administration of 200 mg/day of desipramine with placebo. Response was measured by using the Beck Depression Inventory, the Hamilton Rating Scale for Depression, the Hamilton Rating Scale for Anxiety, and the Impact of Event Scale. Overall, the only apparent response to desipramine was in some symptoms of depression; there were no changes in anxiety and other PTSD symptoms.
Assuntos
Desipramina/uso terapêutico , Transtornos de Estresse Pós-Traumáticos/tratamento farmacológico , Adulto , Ensaios Clínicos como Assunto , Depressão/tratamento farmacológico , Método Duplo-Cego , Humanos , Masculino , Pessoa de Meia-Idade , Veteranos/psicologiaRESUMO
Three biological markers of affective disorders and response to desipramine were used to study the relationship of posttraumatic stress disorder (PTSD) to affective illness. Blunted TRH response and decreased REM latency in eight patients with PTSD occurred at frequencies similar to those that have been found in patients with major affective disorder. Pretreatment Hamilton Rating Scale for Depression and Beck Depression Inventory scale scores were elevated; scores after 4 weeks' treatment with desipramine revealed significant (p less than .05 and p less than .005, respectively) improvement. These findings support a link between PTSD and affective illness.