Correlative light and electron microscopy (CLEM) is a unique method for investigating biological structure-function relations. With CLEM protein distributions visualized in fluorescence can be mapped onto the cellular ultrastructure measured with electron microscopy. Widespread application of correlative microscopy is hampered by elaborate experimental procedures related foremost to retrieving regions of interest in both modalities and/or compromises in integrated approaches. We present a novel approach to correlative microscopy, in which a high numerical aperture epi-fluorescence microscope and a scanning electron microscope illuminate the same area of a sample at the same time. This removes the need for retrieval of regions of interest leading to a drastic reduction of inspection times and the possibility for quantitative investigations of large areas and datasets with correlative microscopy. We demonstrate Simultaneous CLEM (SCLEM) analyzing cell-cell connections and membrane protrusions in whole uncoated colon adenocarcinoma cell line cells stained for actin and cortactin with AlexaFluor488. SCLEM imaging of coverglass-mounted tissue sections with both electron-dense and fluorescence staining is also shown.
Positioning of charged nanoparticles with the help of charge patterns in an insulator substrate is a known method. However, the creation of charge patterns with a scanning electron microscope for this is relatively new. Here a scanning electron microscope is used for the creation of localized charge patterns in an insulator, while a glowing wire generator is used as the nanoparticle source. The deposited palladium nanoparticles are used as catalysts for the localized growth of carbon nanotubes in a chemical vapor deposition oven. The authors show first the results on local carbon nanotube growth using this procedure.
Preface. History of the Concept of Stellar Populations. Report on the Progress in Stellar Evolution to 1950 O. Gingerich. Walter Baade's Discovery of the Two Stellar Populations D. E. Osterbrock. The Discovery of the Chemical Composition-Kinematics Connection in the 1950s N. G. Roman. Stellar Evolution and the Population Concept after 1950 The Vatican Conference A. Blaauw. Globular Cluster Systems. The Galactic Globular Cluster System J. E. Husser. The Stellar Population of a Typical Globular Cluster F. Fusi Pecci and G. Clementini. Stars in the Galactic Halo T. D. Kinman. Globular Cluster Systems in Other Galaxies W. E. Harris. Open Clusters and the Galactic Disk. Evolution of the Galactic Halo and Disk G. Gilmore. Age and Metallicity Distributions among Galactic Disk Stars P. E. Nissen. Early-Type Stars K. C. Freeman. High Velocity Clouds in the Galaxy F.J. Lockman. Chemical Evolution of the Galactic Disk and Bulge R. F. G. Wyse. Stellar Populations in Local Group Galaxies. Stellar Populations in the Magellanic Clouds M. W. Feast. M31 and Companions: A Key to Baade's Stellar Populations Then and Now W. L. Freedman. The Stellar Populations in Local Group Dwarf Galaxies A. Saha. Star Clusters in Local Group Galaxies E. W. Olszewski. Dark Matter in Galaxies. Dark Matter in the Milky Way K. Kuijken. Dark Matter in Spiral Galaxies P. C. van der Kruit. Central Black Holes and Dark Holes in Elliptical Galaxies P. T. de Zeeuw. Dark Matter in Clusters of Galaxies C. R. Canizares. Stellar Populations in Elliptical Galaxies. The UV Upturnin Elliptical Galaxies H. G. Ferguson. The Stellar Ages of Elliptical Galaxies S. M. Faber, S.C. Trager, J.J. Gonzalez, G. Worthey. Stellar Populations in S0 Galaxies R. Bender, A. Paquet. Measuring the Evolution of the M/L Ratio from the Fundamental Plane M. Franx. Effects of Late Mergers F. Schweizer. Environmental Effects in the Stellar Populations of Elliptical Galaxies J. R. Lucey. Galaxies at Large Red Shifts. The Morphological Evolution for Field Galaxies R. S. Ellis. Stellar Populations at Large Redshifts R. W. O'Connell. Galaxy Evolution from Deep Galaxy Counts J. P. Gardner. Classification Schemes of Stellar Populations. Formation Models of Galaxies S. D. M. White. Stellar Dating and Formation of Galactic Spheroids A. Renzini. Panel Discussion on the Classification and Terminology of Stellar Populations I. R. King. Conference Summary J. Mould. Poster Papers. Index.
A novel tunnel junction emitter based on ballistic electron transmission through ultra-thin metal foils is proposed as an electron source. From a simple planar tunneling model and Monte-Carlo simulations, we show that either a high-brightness monochromatic electron source can be obtained or a high-current source with energy spread comparable with a field emission source. Freestanding 5 nm thick Pt films were successfully fabricated for the construction of a tunnel junction electron source, in which a UHV-STM is used as a tip-emitter positioning device.
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To gain better understanding of the shape stability of the Zr/O/W(100) Schottky electron source, the authors investigate the details of the ring collapse. The ring collapse phenomenon has been described and the shrinkage of a stack of the (100) end planes and its eventual disappearance as its W atom and the adsorbed ZrO x entities migrate away from the apex towards the shanks. The investigation of the changes of the full emission pattern in combination with SEM imaging and field simulations has revealed detailed information on shape changes taking place in the ring collapse and the origin of the associated probe current drops. They show the typical probe current profile and the typical facet current profile during a ring collapse and also a typical emission patterns characterizing each stage. In general, the duration of a ring collapse decreases with increasing temperature and decreasing extraction voltage, while the SYMMETRY increases
The design of an electrostatic electron optical system with five electrodes and two objective functions is optimized using multiobjective genetic algorithms (MOGAs) optimization. The two objective functions considered are minimum probe size of the primary electron beam in a fixed image plane and maximum secondary electron detection efficiency at an in-lens detector plane. The time-consuming step is the calculation of the system potential. There are two methods to do this. The first is using COMSOL (finite element method) and the second is using the second-order electrode method (SOEM). The former makes the optimization process very slow but accurate, and the latter makes it fast but less accurate. A fully automated optimization strategy is presented, where a SOEM-based MOGA provides input systems for a COMSOL-based MOGA. This boosts the optimization process and reduces the optimization times by at least ∼10 times, from several days to a few hours. A typical optimized system has a probe size of 11.9 nm and a secondary electron detection efficiency of 80%. This new method can be implemented in electrostatic lens design with one or more objective functions and multiple free variables as a very efficient, fully automated optimization technique.
