RESUMO
High-quality single-phase epitaxial LiCoO2 thin films are synthesized on 0.5 wt % Nb-doped SrTiO3(001) substrates by nanoscale alternate deposition of Li2CO3 and CoO as Li and Co sources, respectively, using a combinatorial pulsed laser deposition (PLD) technique. The formation of LiCoO2 thin films from these two sources results from the sintering reaction between Li2CO3 and CoO, which is commonly used in a bulk ceramics process, but simultaneously takes place on the substrate during the deposition at a temperature of 550 °C. Electrochemical characterization reveals that the charge/discharge property of LiCoO2 thin films as a cathode is severely sensitive to the nominal Li:Co composition ratio. The best-quality film shows an excellent discharge capacity comparable with the characteristic capacity of LiCoO2.
Assuntos
Cobalto/química , Técnicas de Química Combinatória/métodos , Óxidos/química , Estrôncio/química , Titânio/química , Cerâmica/síntese química , Técnicas Eletroquímicas , Lasers , Carbonato de Lítio/química , NanotecnologiaRESUMO
A 72-year-old woman with slowly progressive type 1 diabetes (SPIDDM) was admitted to our hospital because of increasing abdominal pain and diarrhea. The patient was diagnosed with nonocclusive mesenteric ischemia (NOMI), and a subtotal colonectomy was performed successfully. The resected sample revealed transmural gangrenous necrosis of the colon and rectum. This case is interesting because the severe NOMI occurred in a SPIDDM patient without common predisposing events such as hypoperfusion. Prolonged generation of reactive oxygen species in SPIDDM, together with the decline in adaptive response to oxidative stress with aging, might be an exacerbating factor for ischemic injury in the elderly.