bluuebunny/crossref_metadata_2025 huggingface dataset:
Anomalous Changes in Tip Height in Tapping AFM
Authors: Cleveland Jason
Published: March 2018

This effect can be understood by considering what happens to the cantilever and tip as the base of the vibrating cantilever is brought closer to the sample (like in a force curve). When the vibrating cantilever first approaches the surface, the tip senses attractive forces. In standard imaging conditions, these are usually due to meniscus forces between a layer of adsorbed liquid (often water) on the surface of the sample and the tip. However, even in clean conditions, other attractive forces like Van der Waals will generally be present. These attractive forces move the resonance of the cantilever downward in frequency. Since the cantilever is being driven at the original resonance frequency of the cantilever, this will cause the cantilever amplitude to decrease as the attractive forces puli the resonance peak out from under the drive frequency. This decrease is often quite linear with distance, but doesn't have to be. In this case the tip is actually turning around some distance (this could typically be a few nanometers) before it touches the surface. This regime is commonly called the “attractive” regime because attractive forces dominate the behavior of the cantilever.
Exploring Infrastructure With Quantitative 3-D Intermediate Voltage Electron Microscopy
Authors: Gray (Jay) Jerome W
Published: March 2018

The ability to view thick material using accelerating voltages higher than 100 KeV has greatly expanded the usefulness of electron microscopy. At or above 300 KeV, intact cultured cells and tissue sections as thick as 5µm can be visualized. However, under normal viewing conditions this increased depth produces confusing superposition of structures located at different planes along the Z axis. In order to separate spatial information in different planes, specialized procedures such as stereo pairs or animated tilt series have been employed. Although rapid, these procedures do not allow quantitation of parameters such as size, volume, or circumference. Computed Tomography produces a computer generated 3-D reconstruction from which quantitative data can be easily extracted.
Safety Regulations for Alcohol Storage in Laboratories
Authors: Brooks Patrick
Published: March 2018

Questions keep arising regarding safety regulations for storage of alcohol and other flammable liquids in a laboratory. I hope what follows sheds some light on this issue.

Ethanol is classified as a Class IB combustible liquid, Class IB liquids have a maximum allowable container capacity of 20 liters in “metal (non-DOT approved) or approved plastic containers, safety cans or DOT specification metal drums.”

The amount of combustible liquids allowable is determined by the size of the “laboratory unit”. For hospitals with sprinkler systems, per 100 square feet of laboratory space, Class I, II and IIIA (including IB) flammable liquids are limited to 4 L (1.1 gallons) not in approved storage containers or safety cans and 7,5 L (2 gallons) total, including quantities in storage cabinets and safety cans.
Some Notes on Re-Embedding EM Samples
Authors: Chiovetti Robert (Bob)
Published: March 2018

Most of us have been here more than once: a critical specimen, often the only one of its kind, does not embed properly. Usually the problem is incompletely polymerized resin. After the panic subsides, a limited number of options are left, and if the specimen is irreplaceable, there are no options, other than trying to salvage it the best way you can. I've had this problem before with low viscosity resins, but the following suggestions should work for other resins as well.

First of all, realize that reprocessed specimens are rarely as good as they would be if things went fine the first time around.
Increased Preservation of infrastructure With LR Gold for Immunocytochemistry
Authors: Crowley Hiidegard H
Published: March 2018

The acrylic embedding media such as LR White, LR Gold, and others, have long been favored over epoxide embedding media for immunocytochemistry in cases where the antigen is sparse or vulnerable to the chemical activity of epoxy monomers. Since acrylics bond through tissue and not with it as epoxides do (1), Au labeling may increase sharply when acrylics are substituted for epoxides. Unfortunately one serious disadvantage of acrylics is their reduced ability to preserve ultrastructure.
Osmium as an Immunostain Enhancement
Authors: Hawkins Hal
Published: March 2018

Since we do our paraffin-section DAB immunostaining in an EM lab, we often use osmium to darken the reaction product. We simply put a drop of our standard 1% cacodylate-buffered osmium tetroxide on each section in a hood and rinse it off in running tap water after about 2 seconds. It makes light DAB reaction product pretty dark brown, and adds a light brownish tint to the rest of the section. The reaction increases the contrast quite a bit.
Confocal Imaging: In Vivo and Clinical Applications
Authors: Beuerman RW , Kaufman SC , Palkama KA
Published: March 2018

Confocal microscopy is a collection of optical techniques that are applied in a variety of hardware configurations. Design strategies for the application of these techniques have generally used laser light (Pawley, 1990). In most laboratories, basic research use has employed laser light in conjunction with a fluorescent substrate to generate an optical signal, either through direct application of a fluorescent material to cells or by the stimulation of a chromophore associated with an antibody which will identify a cellular protein under some specified experimental conditions, The use of confocal microscopy in this type of situation generally requires a standard research microscope, and the tissue may be situated on a slide or other type of container that will provide a stable, controlled environment.
Using a Focused Ion Beam (FIB) System to Extract TEM-Ready Samples from Complex Metallic and Ceramic Structures
Authors: Giannuzzi Lucille A , Young Richard , Carleson Pete
Published: March 2018

Driven by the analytical needs of microelectronics, magnetic media and micro-fabrication industries, focused ion beam (FIB) systems are now capable of milling and manipulating samples for the analysis of microstructure features having dimensions of 180 nm or less, A technique for locating and extracting site specific specimens for examination by transmission electron microscopy (TEM) has been developed. An identified feature can be located and precisely milled with an FIB system from two sides to prepare an ultrathin sample, and then extracted from the region with a glass rod micromanipulator onto a grid for TEM analysis. This specimen preparation method has been applied to semiconductor failure analysis and to the study of metallic and ceramic microsiructures with irregular topographies and complex mufti-layered components.
Nobel Metal Microscopes - and Other Extravagances
Authors: Gustav Delly John
Published: March 2018

Now you would probably think that I was joking if I were to tell you that there are microscopes made of precious metals, such as silver, rather than brass, and objectives made with diamonds and rubies, rather than glass. But yes, Virginia, prodigal items such as these do actually exist - and not at the end of the rainbow. All right, suppose they do exist, who could afford one? Well, kings for one, Figure 1 shows what is perhaps the most elaborately decorated microscope ever constructed. It was made in 1761 by the wellknown instrument maker George Adams for King George III. George III placed great value on science throughout his long reign, as reflected in his collection of scientific instruments, which can be seen today in the Science Museum at South Kensington in London.
The Art of Tungsten Etching in Semiconductor Chips
Authors: Litz-Montanaro Lisa
Published: March 2018

In the course of both physical and failure analysis of semiconductor chips (i.e., verifying what you actually deposited as a layer, vs, what caused the circuit to fail), it is essential to have appropriate deprocessing tools at your disposal in order to evaluate complex semiconductor structures, Deprocessing techniques are developed for each product manufactured and involve multi-step procedures that reveal the layer-by-layer secrets of the chip, These techniques require constant tweaking in duration and procedure as the manufacturing process imposes changes and as the architecture of the semiconductor changes. While there are many tools that assist in these analytical pursuits, such as RIE (reactive ion etching - a dry etching technique), ion milling, and microcleaving, the wet chemical etching of tungsten is sometimes more reproducible than RIE techniques.
Making the Grade Choosing the Right CCD Camera Chip Grade
Authors: Inoue Ted
Published: March 2018

Today, charge coupled devices (CCDs) have become the de-facto standard for scientific imaging, In fact, their potential for high resolution, sensitivity, wide dynamic range and low noise has made them the device of choice for most fluorescent microscopy imaging applications, This is especially true for quantitative microscopy applications such as ratio imaging, fluorescent in-situ hybridization and image deconvolution.

However, choosing the most appropriate CCD camera for each application can be quite challenging given the broad range of features and performance specifications. This month's article focuses on a single characteristic of the CCD: the chip grade.
Entangled Microscopy
Authors: van Hook Lee
Published: March 2018

The major factor in light microscopy limiting resolution in practice is not so much the wavelength of light and the resolving power of microscope optics, but the scattering of iight by the specimen. This extraneous scattered light interferes with the light used to image the specimen, effectively reducing the contrast of the imaging light and causing other annoying problems, There have been several inventions dedicated to solving this problem: various forms of interference-based microscopies, confocal microscopy, and most recently, multi-photon confocal microscopy.
Virtual Embryology
Authors: Carmichael Stephen W
Published: March 2018

Old embryos are now being looked at in a new way. About a hundred years ago, an embryologist by the name of FranMyn Paine Mall devoted his career to collecting human embryos and fetuses (an embryo becomes a fetus after 2 months of gestation) from miscarriages and abortions. These specimens form the core of what is known today as the Carnegie Collection of Human Embryos, housed in the National Museum of Health and Medicine of the Armed Forces Institute of Pathology in Washington, D.C. Whereas this is a priceless national educational resource, how do we extract the information about our embryonic development from these specimens? Classic techniques involve slicing a specimen as thinly as possible on a microtome, then reconstructing the slices in a model large enough to study. The problem is the specimen is effectively destroyed in the process. What is needed is a technique that allows whole embryos to be examined, but not destroyed.
Another Way To Prepare Permanent Mounts for Light Microscopy
Authors: McCrone Walter C
Published: March 2018

Having read John Kiernan's contribution in the January 1999 issue of Microscopy Today, I decided to add my two-cents worth (ignoring inflation), I have water-mounted preparations older than 5 years with no indications of threats to their permanence. The procedure is so simple it hardly bears writing about much less printing it for others to read.

I simply make sure any aqueous coversiip preparation on a microscope slide be dry at the edges of an otherwise full (of water) coverslip preparation, I simply add tiny amounts of water to completely fill the space between slide and coversiip, then wait a minute or two for the excess water on the slide outside the coversiip to evaporate. I can speed this step by wicking any excessive excess into a forceps-held small square of filter paper.
A Microscope as the Smallest Pen
Authors: Carmichael Stephen W
Published: March 2018

In a movie I saw recently, a young Will Shakespeare was seen to repeatedly dip the nib of a quill into a reservoir of ink and scrawl on pieces of paper until, finally, what we know as "Romeo and Juliet" was penned. As pointed out by Richard Piner, Jin Zhu, Feng Xu, Seunghun Hong, and Chad Mirkin, this technology is much older than Shakespeare, dating back about 4000 years. But even technology this old can change.

As you are well aware, making devices on a smaller and smaller scale (nanofabrication) is certain to change our future way of life, Nanofabrication frequently relies on lithographic methods where a pattern is superimposed on a resistive film and the film is chemically etched to create a structure that conforms to the pattern.
Thoughts About Waste Disposal and Regulations
Authors: Dapson Richard W
Published: March 2018

First, it matters not a bit what others are doing, even if they are doing it with the full knowledge and permission of their wastewater treatment officials. This is because every treatment plant is different, and must set its own limits on chemical waste. Approval must be obtained from local officials.

Getting permission from one's own group of officials may be a pleasant or difficult experience, but the way can be eased a bit by being prepared. Realize that most of them do not know what our histological chemicals are, so provide them with the OSHA mandated hazard codes {e.g., flammable, corrosive, carcinogenic, etc.). They also want to know flash point, pH, miscibility with water and odor (if strong).
Ruthenium Tetroxide: A Complementary Fixative and Stain to Osmium Tetroxide
Authors: Eichelberger Henry
Published: March 2018

Ruthenium tetroxide (RuO4), which is a stronger oxidizing agent than osmium tetroxide (OSO4), reacts well with some of the more polar lipids that fail to show a reaction with OsO4 . it has been demonstrated that the use of RuO4 can overcome the failure of OsC4 to visualize epidermal intercellular lamellae. RuO4 reacts strongly with both saturated and unsaturated lipid molecules, as well as with proteins, glycogen, and monosaccharides. RuO4 fixed membranes appear thicker than those fixed with OsO4 do4.

RuO4 penetrates tissue very slowly and sometimes uneven, patchy preservation may occur. The use of vibratome sections is recommended to optimize penetration of the RuO4 fixative.
Need For Education, Not Just Training
Authors: Foster Barbara
Published: March 2018

Microscopy is unique among its analytical counterparts: it requires a hand-eye-brain coordination not needed in any other type of analytical instrumentation. On one hand, manufacturers of microscopes and auxiliary technologies are working to make systems seamless, transparent, and easier to use. On the other hand, microscopists, even those who will use the microscope as routine tools, need to be knowledgeable in their core disciplines as well as fluent in microscopy and sample preparation. It is not enough that a the person running a microscope be trained to "push this button; turn this knob". Especially as we move into the next millennium, it will become increasingly important to understand the light/matter, electron/matter, or probe/matter interactions which occur when examining a specimen. Microscopists of all descriptions will need to know how to optimize both the sample and the technology, how to interpret the information presented by the image, and how to separate artifact from true information. To compound the problem, the convergence of computer, diverse software packages, microscope, camera, and analytical techniques is producing a new type of multiple level information which, in turn, requires expertise in multiple disciplines.
Correcting Scanning Errors in Scanning Probe Microscopes
Authors: Hsiao Gregor , Leckenby Jezz
Published: March 2018

Scanning probe microscopes (SPMs) are a family of instruments used for studying the surface properties of materials on a dimensional scale ranging from the atomic to the micrometer level. As depicted in Figure 1, all SPMs work by scanning a finely tipped probe in a raster pattern over the sample surface while measuring and mapping some interaction between the probe and the surface as a function of x-y position. The piezoelectric scanners used to provide the scanning motion offer very fine positional control but have certain inherent errors that, uncorrected, can distort images, introduce artifacts, and degrade measurement accuracy.
Automated TEM Sample Preparation
Authors: Kaplan Wayne D , Raz Efrat , Smith Colin
Published: March 2018

The rising demand in the semiconductor industry for higher spatial resolution in the analysis of device defects has focused attention on the use of transmission electron microscopy (TEM). However, conventional TEM sample preparation can be difficult and time-consuming, and, depending on the operator, may result in a low yield of quality specimens. One solution to this problem is the use of focused ion beam (FIB) milling for the final stage of TEM sample preparation. However, specimens have to be mechanically thinned prior to FIB and the need to characterize specific devices requires a pre-FIB preparation method that can target specific features on the wafer. We will discuss an innovative and automated solution that isolates specific devices and prepares TEM specimens for subsequent FIB thinning. The complete pre-FIB preparation takes less than 30 minutes and yields a sample in which the targeted feature is positioned a specific distance from the sample edge, thereby minimizing final FIB milling time. The output specimen is automatically packaged for FIB milling and TEM analysis. We also present drawings of the process flow and examples showing TEM results from tungsten filled vias.
The Birth of the Microscopy Advantage™ CD
Authors: Garber Charles A , Kovacs Kristof
Published: March 2018

In North America, one could very easily get a distorted view of the rest of the world when it comes to internet access. in the USA and Canada, one can stay connected continually, without regard to cost. And the connections tend to be fast and convenient.

But this is not the case in most of the rest of the world. While there are some notable exceptions, Australia and Israel for example, many in the international microscopy and microanalysis community have to struggle with connections that are either very slow, or very expensive, or both, in fact, in many parts of the world, internet content is routinely not with the benefit of graphics. This is really a great disadvantage since, in many instances, the real important information is contained within the graphics. Even in the USA and Canada, because of firewall considerations or other concerns, a surprisingly large number of end users do not have internet access at their main workstations, and they have to suffer the inconvenience of using some kind of shared resource, either “down the hall” or worse yet, in another building.
Isolation and Identification of Paint Pigments by Sublimation
Authors: Palenik Skip J
Published: March 2018

The particle size of organic pigments used in modern coatings is extremely fine. Since these individual pigment crystals are typically less than 1 μm in size, they are difficult, if not impossible, to characterize and identify by microscopical means. The occurrence of occasional pigment aggregates may help identify a pigment to a microscopist who is familiar with a variety of known pigments under controlled conditions. More often, however, such observations provide a qualitative basis for comparison of questioned and known paints without leading to identification of the specific pigments involved. Microscopic observations of this type are assisted by the use of a high-magnification oil immersion objective and condenser with numerical apertures of 1.25 or greater.
The Resolution Revolution
Authors: Carmichael Stephen W
Published: March 2018

The history of microscopy has focused on better and better resolution, as has been documented on these pages [e.g., J.-P Revel). As one can see in the first graph, the early improvement in resolution was agonizingly slow, as it was dependent on technological improvements in optics and methods for preparing specimens. Hans and Zacharias Jensenn are credited with being the first to put two lenses in the same optical path to create a primitive microscope in 1590 Nearly a century later Antoni van Leeuwenhoek was impaling specimens an needles. Whereas van Leeuwenhoek and other observers were able to make significant observations to change fundamental concepts of their day, microscopists such as Ernst Abbe, Hermann Ludwig Ferdinand von Helmholtz, Lord John Rayleigh and Carl Zeiss brougnt us to the brink of optimal performance of the light microscope.
Projector Slide Plates
Authors: Christensen A Kent
Published: March 2018

The preparation of electron micrographs for 2″ x 2″ slide presentations is usually done by photographing EM prints with a 35 mm camera. However, for some of our better electron micrographs, many of us have enjoyed printing the negatives directly on 2″ x 2″ Kodak Projector Slide Plates (#s 140 6875 & 140 6867), which can yield projected images of particularly pleasing tonal quality.

A previous issue of Microscopy Today (issue 94-2, March 1994} contained a brief article my me describing a method for making 2″ x 2″ EM slides with Projector Slide Plates. Unfortunately, it now appears that Kodak has raised the price of these plates to a level that is well beyond what most of us can afford. My first inkling of this came after the article was in the hands of the editor. I telephoned Kodak and confirmed that the price was now about $560 per box of 36 plates, roughly 10 times the former price. However, it still seemed possible that this had been an oversight on the part of Kodak, and that it could be rectified.
More Than One Ever Wanted To Know About X-ray Detectors
Authors: Lund Mark W
Published: March 2018

Spiderman carefully slid the sample of mud into the microscope. As he increased the magnification he caught sight of a tiny spherical crystal. Zooming in on it, he said “Let's see what it's made of”. He reached over and flipped on the x-ray detector. As the spectrum formed on the screen a gasp went through the small group of researchers. “Kryptonite…the intruder is from another comic strip!”

The primary function of a microscope is to get a closer look at a sample. Many times a closer look is enough. Other times you need as much information as possible to solve a problem. In the above example, a reading of the chemical elements contained in the sample gave important clues about the sample's origin. X-ray analysis in electron microscopy combines elemental analysis with high resolution imaging. Of all the analytical techniques available to microscopists, it is the most highly developed and easiest to use.
Is It Possible to Produce Micro-Gravity in Our Own Lab?
Authors: Newberry Sterling
Published: March 2018

Wouldn't it be nice to have some kind of laboratory hood in which gravity is greatly reduced so we could grow more perfect crystals or do biological experiments without having to go into orbit. There was a report in Science last year which hinted that gravity cancellation or modification just might be possible some day, but I doubt that any of our readers noticed it. The title was “Inertia: Does Empty Space Put Up the Resistance?”. One has to read this news report carefully to find that physicists have long pondered the connection between the inertial property of mass and the gravitational attraction between masses and that the work quoted here, suggests that once inertia is understood it might be controlled, even canceled. Upon inquiry the editor, Robert Matthews found other physicists believed that the ability to modify inertia could soon be tested experimentally but remarked that “it is a bit too early to be talking about inertia free star ships.”
Lateral and Chemical Force Microscopy Mapping Surface Friction and Adhesion
Authors: Heaton MG , Prater CB , Kjoller KJ
Published: March 2018

Lateral Force Microscopy (LFU) is a scanning probe microscopy (SPM) technique that identifies and maps relative differences in surface frictional characteristics. It is one of several techniques developed as extensions to the basic topographical mapping capabilities of SPM. LFM is particularly useful for differentiating among materials on surfaces. Applications include identifying transitions between different components in polymer blends, composites and other mixtures, identifying organic and other contaminants on surfaces, delineating coverage by coatings and other surface layers, and chemical force microscopy using functionalized tips.
More Than One Ever Wanted To Know About X-ray Detectors Part IX: Antigravity Holes
Authors: Lund Mark W
Published: March 2018

In this series we have explained why x-ray spectrometers are useful in electron microscopes and, to some extent, how they work. In this article I will discuss some of the physics behind the detector.

First I have been asked to explain what a hole is. In a silicon crystal every silicon atom is bound to four others with covalent bonds. Every electron has a home, which consists of its home atom in the case of the inner electrons. The four outer (or valence) electrons have a home on the road, shuttling back and forth between too atoms each. In this way the five atoms share eight electrons among themselves.
Finding the First Fires with Microscopes
Authors: Carmichael Stephen W
Published: March 2018

Coal is remnants of plant matter that were compressed and held at a high temperature for eons. However, if plants are charred first, they become hard and brittle, and may resist compression. Under appropriate circumstances, anatomic detail can be elegantly retained. Ian Glasspool, Dianne Edwards, and Lindsey Axe have performed detailed studies on plant fossils recovered in England, near the Welsh border, that can be considered to be evidence for the earliest wildfire yet described on our planet. They examined a series of mesofossils, about one millimeter in size, which required microscopic study.

It is well known that chemical and structural changes occur to organic tissues during charring. This can mean that charcoal is resistant to decay and compression and it is also more reflective than non-charred material. Glasspool et al. used incident light and scanning electron microscopy to reveal 3-dimensional cellular detail of the specimens. Additional specimens were embedded and polished for reflectance microscopy. The results indicated that the specimens were charcoal.
Variable Magnification Electron Holography for 2-D Mapping of Semiconductor Devices
Authors: Wang YY , Gribelyuk M , Domenicucci A , Bruley J , Gaudiello J , Kawasaki M
Published: March 2018

The exit electron wave from transmission electron microscopy (TEM) specimens contains both amplitude and phase information. In routine TEM imaging, only amplitude information is recorded on the recording devices (film or CCD camera) and phase information of the electron wave function normally is canceled out.

In 1947, Dennis Gabor proposed off-axis electron holography, a method of interference imaging in which the phase and amplitude components of the electron beam are obtained to correct spherical aberration of the transmission electron microscope to improve spatial resolution. In that process, the electron beam is split into the two beams: the un-scattered electron beam (i.e. the reference wave) and the image beam (or object wave) diffracted by the specimen and exiting the bottom of the specimen surface.
Microwave Processing of Drosophila Tissues for Electron Microscopy
Authors: Buchanan JoAnn
Published: March 2018

Insect tissue is often difficult to prepare for electron microscopy because of the impenetrable barrier surrounding the body tissues. Drosophila salivary glands have been used for numerous studies because of the large size of the cells and their large polytene chromosomes. Early TEM studies of salivary glands used a protocol that took several days. We were able to achieve excellent preservation and good ultrastructure in Drosophila salivary glands and imaginal discs from Stage L3 larvae using microwave processing in a protocol requiring less than 2 hours.

We used a Pelco Laboratory microwave (model #3451) equipped with a Cold Spot, Steadytemp chiller/recirculator run at 15° C, and vacuum chamber (Ted Pella, Mountain Lakes, CA). The heads and attached salivary glands were removed from the animals and placed in PBS. The tissue was transferred to Pelco prep-eze specimen holders (#36157) for ease of handling. Our goal was to use the microwave effect, not the heating effect, to prepare the tissue.
Converting Microscopy Images Into Other Formats
Authors: Bailey Jessica
Published: March 2018

In recent years, microscopy systems have become more capable of capturing, transferring, and manipulating electronic images. In the last issue of this publication, there was a summary of different image format types and their flexibility for use with microscopy. This article will briefly discuss converting images among different formats, which often becomes necessary when transferring images from one software application to another or creating hardcopy of the image. In order to transfer the image, either the original software has to save the image to a format which the new software or output device can read, or that new software or device has to read a format which is native to the image generating software.

Sometimes (happy days), this all works out straightforwardly. Other times, transferring an image is impossible. The user then has the choice of writing his own conversion software, finding freeware, or purchasing a commercial conversion utility.
Microdroplets of Liquid Part I: Glass Fiber Brush
Authors: McCrone Walter C
Published: March 2018

It is very important to be able to deliver tiny droplets of liquid onto any surface. There are two general methods for this. One, a glass fiber brush seaied into a capillary; and, the other, a polyethylene micrapipette. Both are capable of delivering droplets as small as 100 μm in diameter. Description of the glass fiber brush follows. Part II, later in this publication, will describe the polyethylene micropipette.

We have borrowed this clever idea from Fred Schneider of IBM (private communication). A bundle of 20 to 30 glass fibers, 5 to 8 mm long and about 20 μm in diameter, is sealed with a microflame into one end of a glass capillary. A melting point capillary 1 to 2 mm in diameter and open at both ends is convenient (Fig. 1), To use for small drop deposition, the capillary is partly filled (2 to 3 cm. long column of the desired liquid} so that the sealed-in end of the glass fiber bundle is fully immersed.
Application of Slow-Scan CCD Cameras in Routine Biological TEM
Authors: Mooney PE , Krivanek OL , Ray DA , Charlesworth J
Published: March 2018

Slow-scan CCD (charge-coupled device) cameras (SSCs) are based on optical image detection technology introduced in the seventies and first used in astronomy in the eighties. When they are properly configured for the detection of medium energy electrons rather than photons, they are able to capture images that exceed the quality of images recorded on photographic film. Here we discuss aspects of their operation pertinent to routine biological TEM.

Compared to the TV-rate CCD sensors that have become ubiquitous in miniature camcorders, scientific (astronomy-grade) CCDs have several unique characteristics: 1) their pixels are typically 20-27 urn in size rather than the 6 urn typical of TV rate CCDs, 2) their read-out amplifiers are optimized for low noise at read out rates of 1/10 to 1/100 of TV rate, 3) they do not have a separate frame-transfer buffer for CCD read-out, and 4) they are available in large total sizes (up to 2048 x 2048 pixels).
Microscopes aren't just for Microscopists, Anymore (Continued)
Authors: Carmichael Stephen W
Published: March 2018

Microscopes are being used to obtain more and more information from a specimen. We are all acquainted with various ways to visualize structures, whether on the surface or embedded within a relatively translucent specimen. There are many ways to “tag” a molecule of interest so that the molecule can be positively identified within the specimen. Traditional microscopes are not able to identify a molecule for us. Other analytical tools are used for that. For example, the nuclear magnetic resonance (NMR) spectrum of a molecular species yields a “fingerprint” that gives a reliable identification. Wouldn't it be great to combine the sensitivity of a state-of-the-art microscope with the molecular analytical capabilities of NMR?

Well you guessed it, this has been done. This approach was first suggested by John A. Sidles at the University of Washington and has recently been demonstrated by Dan Rugar and colleagues at the IBM Almaden Research Center in San Jose.
The Application of Monte Carlo Modeling to X-Ray Microanalysis
Authors: Chernoff Don
Published: March 2018

X-ray microanalysis (EDS) on a SEM or TEM is a valuable tool for research and industry. No other technique can provide so much information so easily about the chemistry of micro-volumes of a material. Many samples require nothing more than positioning of the electron beam onto the area of interest, collecting a spectra, and 30 seconds later you have your answer. Or do you?

Any technique as widespread and straightforward as energy dispersive x-ray spectroscopy is bound to be misused on occasion. It has been my experience that many users either overestimate the capabilities of EDS to answer difficult materials questions or do not fully appreciate the limitations of the technique and how to work around them. These problems tend to show up as the need to analyze increasingly complex samples increases. The following brief description of the physics of electron beam/specimen interaction may be useful in explaining why problems can exist.
SHaRE: A DOE User Facility For Microscopy and Microanalysis
Authors: Evans ND
Published: March 2018

The Shared Research Equipment (SHaRE) Program at Oak Ridge National Laboratory (ORNL) provides microanalytical facilities to researchers from U.S. universities, industries, and government laboratories for studies within the materials sciences. SHaRE is one of four microscopy and microanalysis research user facilities supported by the U.S. Department of Energy's Office of Basic Energy Sciences (BES). All BES user facilities, including SHaRE, are available to in order to foster collaborative research, scientific leadership, international competitiveness, and the education of graduate students being prepared for careers in materials science. Based on the scientific excellence and relevance of the proposed experiments, free operating time is available to researchers who then publish their results in open literature. Proprietary research can be accomplished on a full cost-recovery basis or by Cooperative Research and Development Agreements (CRADAs). However, services that can be purchased from commercial laboratories are not appropriate for the SHaRE Program.
Force Modulation Imaging
Authors: Heaton MG , Rogers MR , Prater CB
Published: March 2018

Force modulation Imaging is a scanning probe microscopy (SPM) technique that identifies and maps differences in surface stiffness or elasticity. It is one of several new techniques developed as extensions to the basic SPM topographical mapping capabilities. These techniques use a variety of surface properties to better differentiate among materials where topographical differences are small or immeasurable.

Force Modulation Imaging can be used in a wide range of applications including identifying transitions between different components in composites, rubber and polymer blends, evaluating polymer homogeneity, imaging organic materials on hard substrates, detecting residual photoresist on integrated circuits, and identifying contaminants in a variety of materials.
Visions
Authors: Levy Gabor B
Published: March 2018

People who have faced imminent death and survived report visions of their entire lives passing before their eyes. My experience at the recent 50th anniversary meeting of the Electron Microscopy Society of America was similar. In a matter of hours I saw a vision of the entire half-century history of electron microscopy. It was exhilarating.

I was an invited guest among the handful of surviving charter members. Attention was lavished on us and we were treated with TLC (the nursing profession's abbreviation for tender loving care). We recounted our experiences and had an opportunity to meet old friends and colleagues whom we had not seen in years. Most significant, however, were the formal presentations that showed the enormous growth of the field, both in depth and breadth.
Heavy Duty Camera Bellows for Digital Imaging
Authors: Clarke Theodore M
Published: March 2018

My previous article on digital imaging in the April 1997 issue of Microscopy Today noted the use of an Olympus Auto Bellows with a Kodak MegaPlus 1.6i/AB CCD camera for digital photomacrographs equivalent to 4 x 5 Polaroid prints with magnifications between 10X and 50X, The purpose of this article is to document the high resolution obtainable with the bellows system and the design modifications needed to eliminate the plastic dovetail inserts of the Olympus Auto Bellows, which are susceptible to delayed stress cracking when used with a heavier camera like the MegaPlus, Total failure of the dovetail inserts could cause costly damage to the lens and the camera.
Scanning Acoustical Microscopy
Authors: Gallet Jacqueline
Published: March 2018

Scanning acoustical microscopy has found a very comfortable niche in the area of non-destructive evaluation, testing and imaging. But the field need not be limited by such a narrow applications area.

In this article, a general review of current and possible applications will be conducted including archaeological conservation and evaluation. Part III of this series will deal exclusively with biomedical applications.

Since acoustical waves can penetrate a specimen, optically opaque materials can be visualized and more fully examined. Depending on the resolution required, a compromise needs to be achieved before a specimen can be imaged. Recall from Part I of this series, the higher the frequency, the better the resolution, but the depth of penetration is less. In many applications, it is not always necessary to achieve a high degree of resolution, it is more interesting to locate and identify internal structures. Acoustical microscopy is meant to be a complementary form of observation not necessarily a standalone modality.
Methods To Identify Contaminants On Photoresists
Authors: Nieveen Wesley
Published: March 2018

Contaminants on photoresist can be difficult to identify, especially if they are very thin, e.g., less than 0.5 μm. It is very doubtful at the 0.2 μm realm that histological or optical microscopy methods will work, There are several methods available to identify such contaminants1 each giving different degrees or type of information about contaminants.
Reflected/Transmitted Nomarsky DIC Lighting
Authors: Silk Ely
Published: March 2018

What could be better than reflected or transmitted Nomarski differential interference contrast? Why, combining the best features of both and for very little cost. My intended use of the technique was for Nomarski reflection DIC microscopy. It will work, of course, with other types of reflection microscopy.

What this embarrassingly simple artifice accomplishes is to simultaneously add transmission capabilities to reflection observations with the result being improved viewing of delicate details, And, yes, because of the reflective front surface layer, the observer can study details on the bottom side of the specimen which is usually hidden from view. This requires focusing through the specimen and below the point of normal focus.
Fe
2+/ Fe2+ Calculation In Spinels From Oxygen Deficiency Sum
Authors: Chatterjee Nilanjan
Published: March 2018

A typical electron microprobe printout of an oxide analysis shows weight percent concentrations of different elements in terms of their oxides, Fe is usually expressed as FeO. For minerals, it also shows calculated number of cations on the basis of an assumed (theoretical) number of oxygen atoms. For examplejn olivines, (Mg,Fe)2SiO4, the theoretical number of oxygen atoms is four and the sum of cations should add up to three if the analysis is good. However, in case of spinels such as magnetite, Fe3O4, which contain significant amounts of Fe2O3, the analysis total falls below 100 and the cation sum (based on four oxygens) exceeds the theoretical cation sum. in other words, the formula calculation shows an oxygen deficiency. Geologists use this information to calculate the amount of Fe2O3 in the spinel assuming the other cations have only one oxidation state.
Imaging Degraded Wood by Confocal Microscopy
Authors: Kim Yoon Soo , Singh Adya
Published: March 2018

The application of confocal laser scanning microscopy (CLSM) in the studies of biological materials is rapidly expanding because of the opportunity to produce sharp, high resolution images through optical sectioning and computer assisted 3-D reconstruction. At our institute CLSM is being used in a wide range of forestry and wood science studies.

Recently we investigated the potential usefulness of CLSM in characterizing biologically degraded wood. The following are images produced from an archaeological wood which has been buried in a wet environment (rice field) for nearly 2,000 years in South Korea and is apparently degraded by bacteria. In an attempt to develop suitable techniques which can be used for routine examination of fragile degraded wood with CLSM, we have compared two different embedding methods for their suitability in preserving the integrity of cells. The embedding media are paraffin wax and LR White resin.
The Truth in Imaging
Authors: Revel Jean-Paul
Published: March 2018

Several well (and also several not so well) publicized incidents of unethical conduct have raised the concerns of scientists, politicians and common folk that the truth and only the truth may not always emerge from scientific investigation. While this is a problem which clearly needs attention, I believe that Science alone of all fields of human endeavor has built in mechanisms which ensure that truth will emerge sooner or later, usually sooner (although some frauds, for example the Piltdown hoax, survived for quite a long time). This self correcting feature arises from the fact that today's interpretations are repeatedly tested against nature, whenever new methods or hypotheses arise. Only correct beliefs survive this repeated scrutiny. The misguided workers who for whatever reasons “cheat” or get so personally involved that they fall in traps made of their own gullibility are eventually discovered and at the very least lose the recognition that they longed for.
Few Remarkable TEM Facts
Authors: Fraundorf Phil
Published: March 2018

What follows is a list of some physical perspectives on the electrons used routinely for transmission electron microscopy. Without knowing it, you may on a daily basis be putting to practical use things, like the wave nature of electrons, that were inconceivable in the early part of this century. In fact, some of the properties of these electrons may be only marginally conceivable today!
Popcorn, Diffraction and the Computer Revolution
Authors: Schlienger M Eric
Published: March 2018

As is the case with many other aspects of our lives here in the twilight years of the twentieth century, the computer is having an evermore pervasive role in the daily endeavors of the electron microscopist. And as I contemplate the little button on the microwave that allows me to burn popcorn the exact same way, time after time, I am led to wonder “where is it all going?”…the technology that is. I know where the burnt popcorn will end up. Whether we like it or not, the computer is a tool that can drastically improve our productivity, and typically such productivity gains occur precisely within those tasks where mistakes are the most likely to creep in, to wit: the mundane and repetitive.

As an example, consider the task of indexing a diffraction pattern for a known crystal. In the far distant and superstitious past of the mid to late 1960's, this task required all sorts of strange alchemy.
“Scope on a Rope”
Authors: Henk Cindy , Wandersee James , Sundberg Marshall , Silverman Harold
Published: March 2018

We have acquired and made available for loan a durable, easy-to-use, though expensive video-probe microscope. This hand-held, automatically focussing instrument can be used by a 5 year-old and provides instant, excellent, in-focus images of 50X to 200X on a video screen visible simultaneously to all students in the class.

The probe consists of a miniature video camera with interchangeable magnifying “objective” lenses which are surrounded with built-in, cool, fiber-optic illumination. Each lens is capped with a “contact tip” which corresponds to the focal length of the lens and which, when touching the sample, provides automatic focus of the image on the monitor. The images can be videotaped in the normal fashion.
Were the First Microscopes Really That Good?
Authors: Carmichael Stephen W
Published: March 2018

When I see a drawing by an earty microcopist, I am often Impressed by the amount of detail they illustrated. I am frequently amazed by the resolution they apparently were able to achieve with primitive (by today's standards) unconected optics. Were their instruments and observational skills realty that good, or were they just lucky, correctly guessing what was beneath their lens? In an amazing pictorial published in the April issue of Scientific American, Brian Ford convincingly answers this question.

Ford describes the controversies surrounding descriptions by Antony van Leeuwenhoek in 1674 and Robert Brown in 1827. Both of these pioneer microscopists were often dismissed by their contemporaries and ignored for many years after their deaths. Leeuwenhoek was considered to be a man of fertile imagination whose observations of “animalcules” in pond slime were not appreciated until the time of Louis Pasteur.
Hints On Costing Lab Services
Authors: Morken Timothy
Published: March 2018

Costing laboratory services is a huge job and takes a long time to do properly. I've done this many times, but only once from scratch and that one time took six months to finalize. The whole process depends on what the administration really wants and what you have to work with. There should be guidelines given and help forthcoming from the administration, as the results for the lab won't mean much if everyone does it a different way! I wouldn't even start figuring things until the administration gives guidelines and holds some meetings on how it is to be done.
Laser Scanning Confocal Microscopy for Materials Science
Authors: McMillan William
Published: March 2018

Confocal microscopy has gained great popularity in biology and medical research because of the ability to image three-dimensional objects at greater resolution than conventional optical microscopes. In a typical Laser Scanning Confocal Microscope (LSCM), the specimen stage is stepped up or down to collect a series of two-dimensional images (or slices) at each focal plane. Conventional light microscopes create images with a depth of field, at high power, of 2 to 3 μm. The depth of field of confocal microscopes ranges from 0.5 to 1.5 μm, which allows information to be collected from a well defined optical section rather than from most of the specimen. Therefore, due to this “thin” focal plane, out of focus light is virtually eliminated which results in an increase in contrast, clarity and detection.