RESUMEN
We introduce an in situ vacuum procedure for the optimal preparation and analysis of self-assembled monolayers (SAMs) as used in organic molecular electronics on ferroelectric lead zirconate titanate (PZT) substrates. Excellent ordering of oligothiophene semiconductor layers is heavily promoted through the presence of an interfacial bi-functional SAM layer that binds to both the oxidic PZT surface and the organic semiconductor molecules. The described method can be extended to other material combinations, featuring a variety of substrate materials and molecular functionalities.
RESUMEN
Transition metal phthalocyanines (MPc's) are an interesting class of material, and their magnetic and electronic properties are determined by the orbital occupation of the transition metal 3d orbitals incorporated in the molecules center. Thus, the ground state configuration of the transition metal center is very important for a complete understanding of these materials. We present experimental data taken using x-ray absorption and x-ray photoemission spectroscopy together with a theoretical interpretation of MPc series with M=Zn, Cu, Ni, Co, Fe, and Mn. The combination of these methods allows us to narrow down possible dominating ground state configurations and shed a brighter light on the electronic structure of these complexes.
RESUMEN
We report a rare case of spontaneously developing generalised gas gangrene with massive rhabdomyolysis after a cholecystectomy and drainage of a hepatic abscess. On preoperative physical examination the patient appeared severely ill and was icteric and oliguric. Laboratory evaluation showed signs of systemic inflammation, elevated lactate levels, evidence of disseminated intravascular coagulation (DIC), and increased levels of serum creatine kinase (CK) activity. Abdominal ultrasound and endoscopic retrograde cholangiography showed a gallbladder perforation and a hepatic abscess. Cholecystectomy and drainage of the abscess was performed immediately and without technical problems. After postoperative admission to the intensive care unit, the patient showed evidence of generalised myonecrosis with subcutaneous gas formation and acute renal failure. Initially, there were few other signs of systemic toxicity; the patient was not hypotensive and the pulmonary gas exchange was normal. Within hours diffuse swelling of his right leg developed with cutaneous gangrene and a compartment syndrome. After fasciectomy and extensive surgical debridement, uncontrollable bleeding due to DIC developed from the fasciectomy site, which finally required exarticulation of the leg at the hip joint. At this point, multiple organ failure including severe adult respiratory distress syndrome was present. Two days after cholecystectomy, the patient died from hypoxic cardiocirculatory failure. Clostridium perfringens was repeatedly isolated from the wounds. Besides gas gangrene, the differential diagnosis of such infections includes localised clostridial cellulitis, nonclostridial anaerobic cellulitis caused by mixed aerobes and anaerobes, and type I or type II necrotising fasciitis. Patients with systemic necrotising infections should be treated with broad-spectrum antimicrobial regimens (penicillin G, 3rd generation cephalosporins, clindamycin, and aminoglycosides). An otherwise unexplained elevation of serum CK activity in the presence of acute cholecystitis may suggest haematologic spread of an aggressive myolytic agent and the beginning of myonecrosis. This should prompt immediate surgical exploration after establishing broad-spectrum antibiotic coverage. The role of hyperbaric oxygen treatment in this situation remains to be established. If hyperbaric oxygen is to be employed, it should neither delay surgical exploration nor jeopardize the patient with the hazards of an interhospital transport.
