Off-axis electron holography is used to measure electrostatic potential profiles across a silicon p-n junction, which has been prepared for examination in the transmission electron microscope (TEM) in two different specimen geometries using focused ion beam (FIB) milling. Results are obtained both from a conventional unbiased FIB-milled sample and using a novel sample geometry that allows a reverse bias to be applied to an FIB-milled sample in situ in the TEM. Computer simulations are fitted to the results to assess the effect of TEM specimen preparation on the charge density and the electrostatic potential in the thin sample.

Electron back scatter diffraction (EBSD) mapping and indexing has rapidly come into widespread use. However, inadequate attention has been paid to the details of the method. Many of the algorithms in current use were chosen because they were the first ones that were found to work, rather than because they were optimum. Results of systematic study are presented. It is shown that more than one method can successfully correct a sampling artifact, that there is an optimum binning ratio, that Gaussian filtering provides an alternative to “butterfly convolution,” that better alternatives for mapping image quality than those in current use are available, and that saving all the original patterns is practical and advantageous.

Some microalga species may accumulate extracellular polysaccharides, such as a gelatinous mass that encloses its cells, and is known as envelopes, sheaths or capsules. These structures are very common among the Desmidiales. However, studies concerning their functions, properties and structures are still incipient. Spondylosium panduriforme is a filamentous desmids, enclosed by a great and continuous capsule with well-defined borders firmly bond to the cell. These characteristics can be observed through light microscopy in Indian ink preparations. The S. panduriforme capsule is taken as an essential part of the cell, and points out the importance of this structure for its proper functioning [1,2].

Interactions between cells and the surrounding extracellular matrix are important for a number of developmental events. In the heart, cardiac fibroblasts produce the majority of extracellular matrix proteins, particularly collagen types I and III. Cells originating from the proepicardial organ migrate over the surface of the heart, invade the underlying myocardium and ultimately give rise to smooth muscle cells, fibroblasts, and coronary endothelium. Although integrin expression in the developing heart has been well characterized, the expression of Discoidin Domain Receptor 2 (DDR2) remains to be defined. Using confocal microscopy, the expression of DDR2 was examined at several points during cardiac development. Initially, DDR2 expression was detected on the epicardial surface of the heart and on endothelial and mesenchymal cells within the cardiac cushions. As development progressed, DDR2 expression increased at localized regions in the apex and atrioventricular sulcus, although this expression decreased from epicardial to endocardial surface. Eventually, DDR2 expression spanned the myocardial free wall and was detected within the septum. Not until postnatal development was DDR2 expression detected uniformly throughout the myocardium and this distribution was maintained in the adult heart. In summary, the data presented demonstrate that the distribution of DDR2-positive cells changes within the heart during development.

Extended abstract of a paper presented at Microscopy and Microanalysis 2005 in Honolulu, Hawaii, USA, July 31--August 4, 2005

Organizers: John Mansfield and Louis Kerr

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SC01: Towards Nanoscale Imaging of Anything in VPSEM (including ESEM): From Basics to Current Practices. Full Day: 9:00 AM–5:00 PM, Room 317A.

SC02: Image Processing and Analysis. Full Day: 9:00 AM–5:00 PM, Room 317B.

SC03: Photoshop for Microscopy and Microanalysis. Full Day: 9:00 AM–5:00 PM, Room 318A.

SC04: High Pressure Freezing Cryosectioning of Vitrified Samples for Tomography, and Freeze Substitution. Full Day: 9:00 AM–5:00 PM, Room 318B.

SC05: Specimen Preparation for the Physical Sciences. Full Day: 9:00 AM–5:00 PM, Room 319A.

SC06: Digital Microscopy and Image Analysis for Materials Characterization. Half Day: 9:00 AM–1:00 PM, Room 319B.

SC07: Interpretation of Microstructure. Half-Day: 9:00 AM–1:00 PM, Room 323A.

Special Events: Presidential happenings; IMS Henry Clifton Sorby award and lecture; and Art Exhibit.

Educational Venues: Microscopic explorations: A workshop; and It's a Family Affair!

Using electron microscopy, K0.5Na0.5NbO3 (KNN) ceramics sintered at 1030°C for 8 h and 1100°C for 2 and 24 h was studied. The scanning electron microscopy and X-ray spectrometry revealed that the materials consisted of a matrix phase in which the (Na+K)/Nb ratio corresponded closely to the nominal composition and a small amount of Nb-rich secondary phase. A bimodal microstructure of cube-shaped grains was revealed in the fracture and thermally-etched surfaces of the KNN. In the ceramics sintered at 1100°C, the larger grains (up to 30 μm across), contained angular trapped pores. The transmission electron microscopy analysis revealed that the crystal planes of the grains bordering the intragranular pore faces were of the {100} family with respect to the simple perovskite cell. Ferroelectric domains were observed in the grains of this material.

The following shows the correction to Equation (3) that appeared on page 356 of Microscopy and Microanalysis, 11:4, August 2005, in the article by Admon et al. The lines, highlighted with gray screen, were inadvertently left out.

The present study was designed to evaluate the efficacy of different microwave pretreatment methods to retrieve microtubule-associated protein 2 (MAP-2) immunoreactivity in formalin-fixed, paraffin-embedded guinea pig brain sections. Brain sections, microwave pretreated in boiling sodium citrate, citric acid, Tris hydrochloride, and EDTA buffers of pH 4, 6, and 8, were labeled with four different clones of MAP-2 monoclonal antibodies. No MAP-2 immunoreactivity was observed in control sections processed without microwave pretreatment. Optimal MAP-2 immunoreactivity was observed only when MAP-2 antibody clone AP18 was used in conjunction with citric acid buffer of pH 6.0. Using this combination, brain sections from nerve agent soman-exposed guinea pigs were found to exhibit marked reduction in MAP-2 immunostaining in the hippocampus. These observations suggest that the clone of the antibody in addition to the type and pH of antigen retrieval (AR) solution are important variables to be considered for establishing an optimal AR technique. When studying counterpart antigens of species other than that to which the antibodies were originally raised, different antibody clones must be tested in combination with different microwave-assisted AR (MAR) methods. This MAR method makes it possible to conduct retrospective studies on archival guinea pig brain paraffin blocks to evaluate changes in neuronal MAP-2 expression as a consequence of chemical warfare nerve agent toxicity.

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 JoAn Hudson, [email protected] or Nestor Zaluzec, [email protected].

Acute myocardial infarction is a major cause of death and disability in the United States. Introducing thrombolytic agents into the clot to dissolve occlusive coronary artery thrombi is one method of treatment. However, despite advances in our knowledge of thrombosis and thrombolysis, survival rates following thrombolytic therapy have not improved substantially. This failure highlights the need for further study of the factors mediating clot stabilization. Using laser scanning confocal microscopy of clots formed from fluorescein-labeled fibrinogen, we investigated what effect binding of fibrin to the endothelial surface has on clot structure and resistance to lysis. Fluorescent fibrin clots were produced over human umbilical vein endothelial cells (HUVEC) and the clot structure analyzed. In the presence of HUVEC, fibrin near the endothelial surface was more organized and occurred in tighter bundles compared to fibrin just 50 μm above. The HUVEC influence on fibrin architecture was blocked by inhibitory concentrations of antibodies to αV or β3 integrin subunits. The regions of the clots associated with endothelial cells were more resistant to lysis than the more homogenous regions distal to endothelium. Thus, our data show that binding of fibrin to integrins on endothelial surfaces produces clots that are more resistant to lysis.

Extended abstract of a paper presented at Microscopy and Microanalysis 2005 in Honolulu, Hawaii, USA, July 31--August 4, 2005

Biological sciences and physical sciences symposia, advances in instrumentation and techniques symposia, focused interest groups, technologists' forum, and 2006 MSA award submission information.

Surface-sensitive electron spectroscopies, like Auger electron spectroscopy, X-ray photoelectron spectroscopy and elastic peak electron spectroscopy (EPES) are suitable techniques to investigate surfaces and thin layers. A theoretical model for electron transport is needed to process the observed electron spectra. Electron transport descriptions are based on the differential elastic cross sections for the sample atoms and the inelastic mean free path (IMFP) of backscattered electrons. An electron impinging on the sample can lose energy either due to surface or volume excitations. In the present work a Monte Carlo (MC) simulation of the elastic peak of Si, Ag, Ni, Cu, and Au for surface analysis is presented. The IMFP of Si was determined applying the EPES method. The integrated elastic peak ratio of Si with the standard metal reference samples corrected for surface excitation provided IMFP values of Si in the energy range E = 0.2–2.0 keV. Experiments were made with the ESA 31 HSA (ATOMKI) and with the DESA-100 (Staib) spectrometers. Surface correction was based on the application of Chen's model and material parameters. The Monte Carlo simulations of elastically backscattered electron trajectories were made using new EPESWIN software of Jablonski. An improvement of IMFP experimental results was achieved applying the presented procedure.

Principal components analysis (PCA) factor filtering is implemented for the improvement of background removal in noisy spectra. When PCA is used as a method for filtering before background removal in electron energy loss spectroscopy elemental maps, an improvement in the accuracy of the background fit with very short fitting intervals is achieved, leading to improved quality of elemental maps from noisy spectra. This opens the possibility to use shorter exposure times for elemental mapping, leading to fewer problems with, for example, drift and beam damage.

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 JoAn Hudson, [email protected] or Nestor Zaluzec, [email protected].

Date Change: Microscopy & Microanalysis 2006 will take place July 30–August 3, 2006 in Chicago, IL. Please disregard previously listed dates.

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 JoAn Hudson, [email protected] or Nestor Zaluzec, [email protected].

Biological membranes are constituted of lipids organized as a two dimensional bilayer supporting peripheral and integral proteins, providing a barrier between the inside and the outside of a cell [1]. Similar membranes can be prepared from the lipid mixtures forming liposomes. The liposomes are multi or unilamellar spherical vesicles in which an aqueous volume is enclosed and can be used to encapsulate some drugs [2]. In order to better expose the details of their structure, these membranes are generally deposited on the surface of a flat substrate. These supported planar lipid membranes can also provide a model system for investigating the properties and functions of the complex cell membrane and membrane mediated processes such as recognition events and biological signal transduction. Various methods have been used to create artificial lipid membranes supported on a solid surface, being the most used the Langmuir-Blodgett monolayers formation [3], the vesicle fusion or liposome adsorption [4] and the solution spreading [5].

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 JoAn Hudson, [email protected] or Nestor Zaluzec, [email protected]. Please furnish the following information (any additional information provided will be edited as required and printed on a space-available basis):

Polymeric nanoparticles containing an oily core, named nanocapsules (NCs), have been widely studied in the life sciences field due to their therapeutic potentialities of drug targeting in the body accompanied also by its larger stability in the biological fluids compared to other colloidal carriers. Many studies have shown different applications of nanocapsules for therapeutic use concerning their properties [1] of loading poorly water-soluble drugs, protection drugs from inactivation in the gastro-intestinal tract [2], gastric mucosal toxicity protection [3,4], increased drug permeation through mucous epithelium [5,6] and prolongation of drugs in blood circulation for surface modified nanocapsules [7]. The characterization of the nanocapsules is frequently performed by mean size, surface charge of the particles (zeta potential), hydrophobicity, drug loading yield and release kinetic [8]. These features are of great importance for biodistribution profile and interactions with the cells of mononuclear phagocyte system of any injected particles by intravenous route [1]. However, few data on structural organization of the nanocapsules constituents are available in literature and several hypotheses only suggest the presence of an oil "capsular" structure surrounded by a polymeric envelope. Recently, atomic force microscope (AFM) has been used as a method for imaging the surfaces of colloidal systems, such as liposomes [9,10] and nanospheres [11], supplying high resolution information in nanoscaled dimension. In the present work, unloaded nanocapsules were deposited on mica in order to analyze by AFM the diameter, height, particles polydispersion, and topographic characteristics of nanocapsule surface.