Nanoparticles with unconventional shapes may exhibit different types of assembly architectures that depend critically on the environmental conditions under which they are formed. Here, we demonstrate how the presence of polymer (polymethyl methacrylate, PMMA) molecules in a solution, in which CdSe(core)/CdS(pods) octapods are initially dispersed, affects the octapod-polymer organization upon solvent evaporation. We show that a fast drop-drying process can induce a remarkable two-dimensional (2D) self-assembly of octapods at the polymer/air interface. In the resulting structure, each octapod is oriented like a “ballerina”, that is, only one pod sticks out of the polymer film and is perpendicular to the polymer–air interface, while the opposite pod (with respect to the octapod’s center) is fully immersed in the film and points toward the substrate, like a ballerina performing a grand battement. In some areas, a hexagonal-like pattern is formed by the ballerinas in which the six nonvertical pods, which are all embedded in the film, maintain a pod–pod parallel configuration with respect to neighboring particles. We hypothesize that the mechanism responsible for such a self-assembly is based on a fast adsorption of the octapods from bulk solution to the droplet/air interface during the early stages of solvent evaporation. At this interface, the octapods maintain enough rotational freedom to organize mutually in a pod–pod parallel configuration between neighboring octapods. As the solvent evaporates, the octapods form a ballerina-rich octapod-polymer composite in which the octapods are in close contact with the substrate. Finally, we found that the resulting octapod-polymer composite is less hydrophilic than the polymer-only film.

Generalized peritonitis causes a reduction in abdominal fibrinolytic activity, resulting in persistence of intraabdominal fibrin with subsequent adhesion and abscess formation. The activities of tissue plasminogen activator (tPA) and plasminogen activator inhibitor (PAI) were measured in the peritoneal fluid of rats with faecal peritonitis and correlated with the extent of peritoneal damage to determine the cause of decreased fibrinolysis. Activity of tPA was low during the study period of 8 days, but higher in rats with peritonitis than in controls. The activity of PAI in rats with peritonitis was significantly increased compared with that of controls during the whole study period (P < 0.001). Histological signs of damage to the peritoneum were similar in rats with peritonitis and controls. There was no correlation between the extent of peritoneal damage and tPA or PAI activity. The increased activity of PAI in the peritoneal fluid of rats with faecal peritonitis may be the main cause of reduced fibrinolysis in the abdominal cavity. Activities of tPA and PAI may originate not only from the mesothelium but from other sources.

PurposeThis article summarises the results of a newly developed technique that utilises Meniscus Arrows® for the arthroscopic fixation of displaced tibial spine fractures in children and adolescents.MethodTwelve tibial spine fractures in the knees of eleven children between 6 and 15 years old, with an average age of 12 years, were arthroscopically fixed with Meniscus Arrows®, after a reduction of their fractures. This was followed by 5 weeks immobilisation in a plaster of Paris. Postoperative follow-up included radiographs, Lachmann tests on all of the children’s knees and KT-1000 tests of eight out of twelve of the children’s knees. The postoperative follow-up time ranged from 3 to 10 years, with patients being seen for an average of 4 years.ResultsAll of the fractures consolidated uneventfully, and all of the patients returned unrestricted to their previous activity level. The Lachmann tests revealed no, or a non-functional, laxity in any of the patients’ knees. The KT-1000 tests showed a difference between the operated side, and non-operated side, of between 3 mm in the first knee operated on and an average of 1 mm in the remaining knees.ConclusionThe arthroscopic fixation of tibial spine fractures using Meniscus Arrows® showed that this minimally invasive procedure resulted in the uneventful consolidation of all twelve of the fractures, with excellent results, and without the need for a second, hardware removal, operation. Level of Evidence: Level IV

Simultaneous fractures of the distal radius and scaphoid is an uncommon wrist injury. During the period 1980 to 1993, 23 patients with a median age of 39 years were treated for this injury. The median follow-up period was 7 years. All scaphoid fractures were undisplaced and located in the waist or distal third. An extraarticular distal radial fracture was observed in 15 wrists. A below elbow cast including the thumb was applied in 18 wrists for a mean duration of 9 weeks, and operative treatment was used in only 5 patients. All scaphoid fractures healed without complications. During conservative treatment there were three redisplacements of distal radial fractures. The final functional results were good in 18, fair in four, and poor in one patient. Because complications occurred at the distal radius we have changed our conservative treatment policy from a below elbow cast including the thumb to a dorsal splint for 6 weeks.

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