Combined thermal and FTIR analysis of porous silicon based nano-energetic films

Combinations of analytical techniques lead to new insights for the early stages of explosive reactions.

Biomineralization of gold in biofilms of Cupriavidus metallidurans

Cupriavidus metallidurans, a bacterium capable of reductively precipitating toxic, aqueous gold(I/III)-complexes, dominates biofilm communities on gold (Au) grains from Australia. To examine the importance of C. metallidurans biofilms in secondary Au formation, we assessed the biomineralization potential of biofilms growing in quartz-sand-packed columns to periodic amendment with Au(I)-thiosulfate. In these experiments, >99 wt % of Au, was retained compared to <30 wt % in sterilized and abiotic controls. Biomineralization of Au occurred in the presence of viable biofilms via the formation of intra- and extra-cellular spherical nanoparticles, which aggregated into spheroidal and framboidal microparticles of up to 2 μm in diameter. Aggregates of Au formed around cells, eventually encapsulating and ultimately replacing them. These particles were morphologically analogous to Au-particles commonly observed on natural Au grains. Bacterial cells were connected via exopolymer or nanowires to μm-sized, extracellular Au-aggregates, which would intuitively improve the flow of electrons through the biofilm. This study demonstrates the importance of C. metallidurans biofilms for the detoxification of Au-complexes and demonstrates a central role for bacterial biomineralization in the formation of highly pure Au in surface environments.

Objectives to direct the training of emergency medicine residents on off-service rotations: hand surgery

This is the fifth article in a continuing series on objectives to direct the training of emergency medicine residents. The emergency physician frequently must deal with hand injuries. Often these may appear innocuous; recognition of these injuries requires certain technical skills and a working knowledge of these entities. Specific objectives presented provide guidance for the didactic content as well as skill mastery for the resident experience.

Objectives to direct the training of emergency medicine residents in off-service rotations: plastic surgery

This is the fourth article in a continuing series on objectives for emergency medicine training; plastic surgery objectives will be presented. Plastic surgery topics overlap many in emergency medicine. Specific behaviorally based objectives for mastery of skills in plastic surgery are outlined. Specific references are provided for additional information and reinforcement in skill mastery. The basic concepts of plastic surgery are probably best learned by observation and supervised performance. Specific objectives provide guidance and direction for the didactic as well as the supervised experiences in skill mastery. These objectives provide a structure for systematically learning and mastering the content presented on a plastic surgical rotation or experience in emergency medicine training.