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The bacteriochlorophyll (Bchl) c content and organization was determined for Chlorobium (Cb.) tepidum chlorosomes, the light-harvesting complexes from green photosynthetic bacteria, using fluorescence correlation spectroscopy and atomic force microscopy. Single-chlorosome fluorescence data was analyzed in terms of the correlation of the fluorescence intensity with time. Using this technique, known as fluorescence correlation spectroscopy, chlorosomes were shown to have a hydrodynamic radius (Rh) of 25 +/- 3.2 nm. This technique was also used to determine the concentration of chlorosomes in a sample, and pigment extraction and quantitation was used to determine the molar concentration of Bchl c present. From these data, a number of approximately 215,000 +/- 80,000 Bchl c per chlorosome was determined. Homogeneity of the sample was further characterized by dynamic light scattering, giving a single population of particles with a hydrodynamic radius of 26.8 +/- 3.7 nm in the sample. Tapping-mode atomic force microscopy (TMAFM) was used to determine the x,y,z dimensions of chlorosomes present in the sample. The results of the TMAFM studies indicated that the average chlorosome dimensions for Cb. tepidum was 174 +/- 8.3 x 91.4 +/- 7.7 x 10.9 +/- 2.71 nm and an overall average volume 90,800 nm(3) for the chlorosomes was determined. The data collected from these experiments as well as a model for Bchl c aggregate dimensions was used to determine possible arrangements of Bchl c oligomers in the chlorosomes. The results obtained in this study have significant implications on chlorosome structure and architecture, and will allow a more thorough investigation of the energetics of photosynthetic light harvesting in green bacteria.

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Chemical and structural evolution of hydroxyapatite thin films produced by sol‐gel synthesis is characterized by ion beam analysis, X‐ray diffraction, and Fourier transform infrared spectroscopy. Formation of the hydroxyapatite structure began at 500°C; no other phases were observed at higher temperatures. Elimination of residual organics was observed in the form of the disappearance of excess oxygen, hydrogen and carbon. Crystal size increases with increasing anneal temperature; spectroscopy indicates the formation of highly crystalline films. The analytical methods chosen provide insight into subtle chemical and structural changes which occur in films produced by this synthetic route.

The accreditation criteria for engineering programs require that the curriculum introduce students to the ethical, social, economic and safety issues arising from the practice of engineering. Graduates must also demonstrate competence in written and oral communication skills. This paper describes a bioengineering course we developed at Arizona State University to satisfy these criteria and also meet the literacy and critical inquiry requirement of the university. The primary goal of the course is to increase the students' awareness of the global "societal" issues arising from the development and use of bioengineering technology. Secondary goals include improvement of skills in literacy and critical inquiry, oral communication, and teaming. We use cooperative learning to ensure student participation, creative controversy to stimulate interest in the topics being discussed, and TQM tools to enhance team performance. This paper describes the course content, its organization and structure, the methods used to assess student performance, and the strategies we use to facilitate learning. We also discuss how students have reacted to the course and our experiences in delivering the course.