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Atom probe tomography was utilized to measure directly the chemical compositions of Al3(Zr1−xTix) precipitates with a metastable L12 structure formed in Al-0.1Zr-0.1Ti (at.%) alloys upon aging at 375°C or 425°C. The alloys exhibit an inhomogeneous distribution of Al3(Zr1−xTix) precipitates, as a result of a nonuniform dendritic distribution of solute atoms after casting. At these aging temperatures, the Zr:Ti atomic ratio in the precipitates is about 10 and 5, respectively, indicating that Ti remains mainly in solid solution rather than partitioning to the Al3(Zr1−xTix) precipitates. This is interpreted as being due to the very small diffusivity of Ti in α-Al, consistent with prior studies on Al-Sc-Ti and Al-Sc-Zr alloys, where the slower diffusing Zr and Ti atoms make up a small fraction of the Al3(Sc1−xTix/Zrx) precipitates. Unlike those alloys, however, the present Al-Zr-Ti alloys exhibit no interfacial segregation of Ti at the matrix/precipitate heterophase interface, a result that may be affected by a significant disparity in the evaporation fields of the α-Al matrix and Al3(Zr1−xTix) precipitates and/or a lack of local thermodynamic equilibrium at the interface.

Increasingly, genetically modified Salmonella are being explored as a novel treatment for cancer because Salmonella preferentially replicate within tumors and destroy cancer cells without causing the septic shock that is typically associated with wild-type S. typhimurium infections. However, the mechanisms by which genetically modified Salmonella strains preferentially invade cancer cells have not yet been addressed in cellular detail. Here we present data that show S. typhimurium strains VNP20009, LT2, and CRC1674 invasion of PC-3M prostate cancer cells. S. typhimurium-infected PC-3M human prostate cancer cells were analyzed with immunofluorescence microscopy and transmission electron microscopy (TEM) at various times after inoculation. We analyzed microfilaments, microtubules, and DNA with fluorescence and immunofluorescence microscopy. 3T3 Phi-Yellow-mitochondria mouse 3T3 cells were used to study the effects of Salmonella infestation on mitochondria distribution in live cells. Our TEM results show gradual destruction of mitochondria within the PC-3M prostate cancer cells with complete loss of cristae at 8 h after inoculation. The fluorescence intensity in YFP-mitochondria-transfected mouse 3T3 cells decreased, which indicates loss of mitochondria structure. Interestingly, the nucleus does not appear affected by Salmonella within 8 h. Our data demonstrate that genetically modified S. typhimurium destroy PC-3M prostate cancer cells, perhaps by preferential destruction of mitochondria.

Extended abstract of a paper presented at MC 2007, 33rd DGE Conference in Saarbrücken, Germany, September 2 – September 7, 2007

The morphology of the outer and inner membranes of traumatic chronic subdural hematomas (CSDHs) surgically removed from eight patients was investigated by scanning electron microscopy (SEM). Hematomas were divided into three groups based on time that had passed from the initiation of trauma to surgery. Structure of the CSDHs showed gradual morphological changes of the developing hematoma capsule. They initially included angiogenic and aseptic inflammatory reactions followed by progressive involvement of fibroblasts—proliferating and producing collagen fibrils. Numerous capillaries suggesting formation of new blood vessels were observed mainly in young hematomas removed between 15 and 21 days after trauma. In “older” hematomas (40 days after trauma), more numerous capillaries and thin-walled sinusoids were accompanied by patent, larger diameter blood vessels. Within the fibrotic outer membrane of the “oldest” hematoma capsules (60 or more days after trauma), especially in the area over the hematoma cavity, blood vessels were frequently occluded by clots. The results suggest dynamic changes in cellular and vascular organization of traumatic CSDH capsules paralleling the progression in hematoma age.

Image Analysis of Food Microstructure. John C. Russ. CRC Press, Boca Raton, FL; 2005, 369 pages. ISBN 0-8493-2241-3

Understanding food microstructure is fundamental to understanding the changes fresh fruit and vegetables undergo during development, postharvest, and during processing and preservation treatments, such as canning, drying, and freezing. Microstructure is also important in manufactured foods and in the development of new types of foods to give insight into the way in which ingredients respond when mixed with others and how they compete for space in a volume. Microstructure is important for food scientists because it gives rise to quality aspects, including texture, color, and palatability of foods. Finding innovative ways to examine food microstructure not only helps the fundamental understanding but also allows us to solve problems for industry when products fail.

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Following is a list of microscopy-related meetings and courses. The editors would greatly appreciate input to this list via the electronic submission form found in the MSA World-Wide Web page at http://www.msa.microscopy.com. We will gladly add hypertext links to the notice on the web and insert a listing of the meeting in the next issue of the Journal. Send comments and questions to Nestor Zaluzec, [email protected].

Extended abstract of a paper presented at Microscopy and Microanalysis 2007 in Ft. Lauderdale, Florida, USA, August 5 – August 9, 2007

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Adeno-associated virus (AAV) is a defective, nonpathogenic human parvovirus, which coinfects with a helper adenovirus or herpes virus. AAV's unique characteristics have made it an appealing vector system for gene delivery. AAV or recombinant AAV (rAAV) has been widely detected using negative stain transmission electron microscopy (TEM) but little has been detected using atomic force microscopy (AFM). In this article, we used AFM and TEM to observe the recombinant AAV-2 (rAAV-2) virus particles and applied statistical analysis to the AFM and TEM images. The results indicated that the rAAV-2 particle was a slightly elliptic particle close to round when it was detected by TEM (the mean length of major and minor axes of rAAV-2 particles was 24.77 ± 1.78 nm and 21.84 ± 1.57 nm, respectively), whereas when detected by AFM, the rAAV-2 particle was almost round. Even though the dimensions of the rAAV-2 particle exhibited a polymorphous distribution via off-line particle analysis of AFM, most of the rAAV-2 particles had a mean diameter of approximate 22.04 nm, which was similar to the results obtained by TEM. The results above suggested that AFM was important for accurately determining the average dimensions and distributions of virus particles.

Extended abstract of a paper presented at MC 2007, 33rd DGE Conference in Saarbrücken, Germany, September 2 – September 7, 2007

The urinary bladder is an unusual organ in that its normal function includes filling and emptying with alternating changes in internal pressure. Although fluctuations in blood flow to the bladder wall are known to accompany these changes, detailed descriptions of the bladder microvasculature are sparse. The present study uses vascular corrosion casting and scanning electron microscopy to describe the three-dimensional anatomy of the microvasculature of the urinary bladder of the dog. Specialized features of that microvasculature, including collateral circulation, vessel folding, vessel orientation, the presence of valves and sphincters, and mucosal capillary density, that may enhance and control blood flow during normal bladder function, are described and discussed.

Extended abstract of a paper presented at Microscopy and Microanalysis 2007 in Ft. Lauderdale, Florida, USA, August 5 – August 9, 2007

Methods in Molecular Biology Series: Cell Imaging Techniques: Methods and Protocols. Edited by Douglas J. Taatjes and Brooke T. Mossman. Human Press, Inc., Totowa, NJ; 2005, 512 pages. (Hardcover and e-book, U.S. $125.00) ISBN 978-1-58829-157-8

Cell Imaging Techniques: Methods and Protocols, edited by Douglas J. Taatjes and Brooke T. Mossman, is Volume 319 in the long-standing Humana Press Methods in Molecular BiologyTM series. Unlike many of the books in the series that focus on a specific technology, growth factor, or cell type, this volume covers a wide range of technology and applications. As the editors state in the Preface, their goal is to “present an eclectic collection of what we consider some of the essential state-of-the-art methods for imaging cells and molecules.” While the editors have done a good job of collecting chapters that represent a range of cell imaging techniques, I believe this represents both the strength and the weakness of the work. In a situation such as a core facility where a wide variety of instrumentation and applications are being used, this will provide a reference text for a number of technologies. However, if an investigator is searching for a work focused on the study of a specific technology, cell type, or molecule, other volumes may be more applicable.

Following is a list of microscopy-related meetings and courses.

Microscopy and Microanalysis 2007 will be the premiere meeting of the year for scientists and technologists worldwide who use microscopy and microanalysis in their research. We believe that there will be much to interest each of you, and we hope that you will take advantage of the unique interdisciplinary nature of the Microscopy and Microanalysis meetings as a way to broaden your knowledge by learning about techniques and applications that may be somewhat outside your main research focus. We have aimed to give equal emphasis to applications in both biological and physical science, while soliciting symposia that reflect current and emerging trends in microscopy and microanalysis, and in the development of associated instrumentation. We look forward to meeting and interacting with as many of you as possible at Fort Lauderdale.

Extended abstract of a paper presented at MC 2007, 33rd DGE Conference in Saarbrücken, Germany, September 2 – September 7, 2007

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