bluuebunny/crossref_metadata_2025 huggingface dataset:
Equity implications of rice fortification: a modelling study from Nepal
Authors: Saville Naomi M , Maharjan Macharaja , Manandhar Dharma S , Harris-Fry Helen A
Published: July 2020

Objective:

To model the potential impact and equity impact of fortifying rice on nutritional adequacy of different subpopulations in Nepal.

Design:

Using 24-h dietary recall data and a household consumption survey, we estimated: rice intakes; probability of adequacy (PA) of eight micronutrients commonly fortified in rice (vitamin A, niacin (B3), pyridoxine (B6), cobalamin (B12), thiamin (B1), folate (B9), Fe and Zn) plus riboflavin (B2), vitamin C and Ca and mean probability of adequacy (MPA) of these micronutrients. We modelled: no fortification; fortification of purchased rice, averaged across all households and in rice-buying households only. We compared adequacy increases between population subgroups.

Setting:

(i) Dhanusha and Mahottari districts of Nepal (24-h recall) and (ii) all agro-ecological zones of Nepal (consumption data).

Participants:

(i) Pregnant women (n128), mothers-in-law and male household heads; (ii) households (n4360).

Results:

Unfortified diets were especially inadequate in vitamins B12, A, B9,Zn and Fe. Fortification of purchased rice in rice-purchasing households increased PA > 0·9 for thiamin, niacin, B6, folate and Zn, but B12and Fe remained inadequate even after fortification (PA range 0·3–0·9). Pregnant women’s increases exceeded men’s for thiamin, niacin, B6, folate and MPA; men had larger gains in vitamin A, B12and Zn. Adequacy improved more in the hills (coefficient 0·08 (95 % CI 0·05, 0·10)) and mountains (coefficient 0·07 (95 % CI 0·01, 0·14)) but less in rural areas (coefficient −0·05 (95 % CI −0·09, −0·01)).

Conclusions:

Consumption of purchased fortified rice improves adequacy and gender equity of nutrient intake, especially in non-rice-growing areas.
Addressing embodied inequities in health: how do we enable improvement in women’s diet in pregnancy?
Authors: McKerracher L , Oresnik S , Moffat T , Murray-Davis B , Vickers-Manzin J , Zalot L , Williams D , Sloboda DM , Barker ME
Published: July 2020

Objective:

To disrupt cycles of health inequity, traceable to dietary inequities in the earliest stages of life, public health interventions should target improving nutritional wellbeing in preconception/pregnancy environments. This requires a deep engagement with pregnant/postpartum people (PPP) and their communities (including their health and social care providers, HSCP). We sought to understand the factors that influence diet during pregnancy from the perspectives of PPP and HSCP, and to outline intervention priorities.

Design:

We carried out thematic network analyses of transcripts from ten focus group discussions (FGD) and one stakeholder engagement meeting with PPP and HSCP in a Canadian city. Identified themes were developed into conceptual maps, highlighting local priorities for pregnancy nutrition and intervention development.

Setting:

FGD and the stakeholder meeting were run in predominantly lower socioeconomic position (SEP) neighbourhoods in the sociodemographically diverse city of Hamilton, Canada.

Participants:

All local, comprising twenty-two lower SEP PPP and forty-three HSCP.

Results:

Salient themes were resilience, resources, relationships and the embodied experience of pregnancy. Both PPP and HSCP underscored that socioeconomic-political forces operating at multiple levels largely determined the availability of individual and relational resources constraining diet during pregnancy. Intervention proposals focused on cultivating individual and community resilience to improve early-life nutritional environments. Participants called for better-integrated services, greater income supports and strengthened support programmes.

Conclusions:

Hamilton stakeholders foregrounded social determinants of inequity as main factors influencing pregnancy diet. They further indicated a need to develop interventions that build resilience and redistribute resources at multiple levels, from the household to the state.
Possibilities And Examples For Remote Microscopy Including Digital Image Acquisition, Transfer, and Archiving
Authors: Daberkow I , Schierjott M
Published: July 2020

Recent developments promise the possibility to externally control every aspect of microscopes through a computer interface. In combination with high-resolution cameras and feedback to the microscope, this can be leveraged to create highly automatic routines, e.g., to remotely correct astigmatism. Together with the development of fast computer networks this creates a new branch of microscopy, the so-called “telemicroscopy”. The goal of telemicroscopy is the control of a microscope over a large distance including the transfer of images with an acceptable repetition rate. A big advantage for electron microscopy in particular is the possibility of having access to expensive and well-equipped microscopes. In the field of light microscopy the branch “telemedicine” was created, meaning the “virtual” presence of a colleague or specialist for discussion or diagnosis.

Using transmission electron microscopy as an example, the history and special requirements for automation and telemicroscopy will be discussed. In the late 80's the first TEM with a remote control was revealed. Shortly thereafter, first automatic functions for defocus control and astigmatism correction were developed using a video camera as electronic image converter.
The Materials Microcharacterization Collaboratory
Authors: Wright Michael C
Published: July 2020

The Materials Microcharacterization Collaboratory (MMC) was created last year as a pilot project within the US Department of Energy's DOE2000 program. The DOE2000 program has three main goals: improved ability to solve DOE's complex scientific problems, increased R&D productivity and efficiency, and enhanced access to DOE resources by R&D partners. One of the strategies to meet these goals is the construction of national collaboratories. These provide integration on the Internet of unique or expensive DOE research facilities and expertise for remote collaboration, experimentation, production, software development, modeling, or measurement. In addition, collaboratories will benefit researchers by providing tools for video conferencing, shared data-viewing, and collaborative analysis. Cooperative pilots projects, jointly funded by DOE2000 and a scientific program area, are expected to lead to clear success in the scientific environment: they are to provide new capabilities and to increase the efficiency of doing the work (e.g., reduce travel, increase communication, provide for sharing of data among formerly disparate environments).
A Testbed for Automated Acquistion From a TEM
Authors: Potter CS , Carragher B , Chu H , Frey B J , Josephs R , Lin C , Kisseberth N , Miller KL , Nahrstedt K
Published: July 2020

We are developing a testbed for automated identification of specimens, and acquisition of high resolution images for 3D macromolecular EM. Several software package which have been developed specifically for acquisition of tomographic data sets have illustrated the benefits of automation. These software packages require the user to identify a specimen of interest and then automatically acquire a single tilt series from the identified specimen. The testbed we are developing will provide a generalized system for specimen identification, image acquisition and image quality assessment. The goals of the testbed are to provide a system that will acquire EM images unattended by an operator.

The testbed integrates a computer controlled TEM with a distributed real-time image processing environment. Computerized control and image acquisition from the TEM uses the emScope software package (1). This is coupled to existing image processing software packages and new software tools developed specifically for this project.
Telemicroscopy: Development of a Collaboratory for Microscopic Digital Anatomy
Authors: Ellisman M H , Hadida M , Greer D , Wong M , Lindsey S , Peltier S , Young SJ
Published: July 2020

Our original “Telemicroscopy” project has now been expanded into a project in which we aim to provide a “Collaboratory for Microscopic Digital Anatomy” (CMDA) Tools being developed will provide a researcher at a remote site distributed interaction with unique instrumentation for data acquisition, as well as significantly enhanced capabilities to derive and analyze 3D data by accessing high performance computers. Initial focus is on the collection and analysis of data from a unique IVEM located at the National Center for Microscopy and Imaging Research (NCMIR). The NCMIR instrument is one of a few IVEMs in the USA made available to the biological research community by the National Center for Research Resources of the National Institutes of Health. This particular instrument was specially designed to obtain images from thick specimens containing substantial 3D structure. Because of the characteristics of the EM, images acquired represent two dimensional projections of the 3D structure within the specimen.
A Generic Protocol for Controlling an SEM over a TCP/IP Link
Authors: Ritchie Nicholas W M , Woods Paul V
Published: July 2020

In recent years, a number of different groups(1) have investigated and reported on implementing Web-based controls for SEMs and TEMs. Through telemicroscopy, as the field is often known, they have demonstrated that expensive microscopy resources can be shared and the experience of remote experts utilized in an efficient, cost-effective manner. Up to this point most technological demonstrations of telemicroscopy have been implemented as retrofits to existing microscopes. As retrofits, these demonstrations had limitations which a system designed from day one as a networked instruments could avoid. present here details of an ongoing project at R.J. Lee Instruments to redesign the software interface to our Personal SEM product around a TCP/IP link between the SEM hardware and the user interface. All communications between the SEM and console, including commands and image data are transmitted over a single 10-BaseT Ethernet link using the connection-oriented TCP protocol.
Tele-Tutoring - From Learning to Earning
Authors:   West Greene School District Team,   RJ Lee Group Team, Koshinski L S , Weinrich L T
Published: July 2020

The West Greene School District (WGSD) in southwestern Pennsylvania has been extremely aggressive in providing exceptional educational opportunities to its students which come primarily from a rural, small-town and post-industrial mining community. The five school systems serving Greene County have been linked with multiple T-l lines making special interest courses available to all students through a sophisticated distancelearning facility. The goals of this program are multiple including motivating students to pursue advanced education, especially in mathematics, computer sciences, engineering, and the basic sciences; enriching the educational experience beyond that commonly available to students in rural communities; and improving the general attractiveness of the region for business growth.

RJ Lee Group (RJLG) is a small business located about 60 miles northeast of Greene County specializing in solving materials-related problems. Scanning electron microscopy (SEM) is often one of the methods used by RJLG.
A Multi-Instrument Virtual Collaborative Environment VIA the Worldwide-Web at Nist
Authors: Thorne B B , Steel E B , Fahey A J
Published: July 2020

Control of electron microscopes by a remote networked computer system has been implemented successfully in a variety of ways including via the World Wide Web (WWW). This approach works well with users who are familiar with the operation of the instrument and are experienced microscopists. However, many of our collaborations involve other scientists or engineers looking to us for analytical expertise. In order to accommodate collaborators with a broad range of skills and to allow them to interact remotely, in near-real time with a scientist operating an instrument, we have implemented a Virtual Collaborative Environment (VCE) based on a WWW server and the use of the server-push protocol.

The system developed at NIST is a frames-based WWW page that is presented to the user with an index of instruments on the left side (FIG.l), live video pages to the right side, and a download area (via ftp) toward the bottom for data and high resolution images.
Televisualization: An Aid To Collaborative Research In Molecular Structure Biology
Authors: Schmid M F , Matsudaira P , Dougherty M T , Sherman M B , Henn C , Chiu W
Published: July 2020

Collaboration between local microscopists and image processing specialists, and their remote biological colleagues, has been hampered by the difficulty of i) transferring the three-dimensional reconstructions of macromolecules resulting from the cryomicroscopy and image processing, ii) viewing the results in a meaningful way, and iii) communicating the results and the interpretations derived therefrom to each other.

The acrosomal process is an intracellular quasi-crystalline organelle in the head of the sperm of the horseshoe crab Limulus polyphemus. It consists of 100 - 130 actin-scruin filaments packed together in a pseudo-hexagonal lattice and is up to 60 μm long with a diameter of 0.1 μm. Scruin-scruin interactions are responsible for cross-linking the actin filaments together in the bundle. Our goal was to reveal interfilament interactions in the bundle. We have taken tilt series images in the electron microscope to reconstruct its three-dimensional structure at 45 Å resolution.
Design and Implementation of a Laboratory-Wide Image Management System Based on Microsoft Windows NT and Optical Storage Technology
Authors: Rick McGill
Published: July 2020

The advent of digital imaging in microscopy has inspired many changes to the conventional generation and presentation of photographic image data. The demise of the photographic darkroom is a direct result of the prolific electronic image format. Digital images offer extensive flexibility with respect to image manipulation and analysis, duplication, technical presentations, and data transfer to remote locations. With this advance to digital technology come new obstacles for the "traditional" microscopy laboratory to hurdle once this technology is implemented. A few of these obstacles include data storage and retrieval systems, networking of analytical instruments, and adequate software for image manipulation.

The intent of this presentation is to introduce the analytical community to a successful implementation of a laboratory-wide image management system, specifically, the strategies behind the concept and completion of the system and successes gained therefrom.
Real-Time Remote Control of a Scanning Electron Microscope Across the vBNS/Internet 2
Authors: Mansfield John F , Adamson Andy , Coffman Kevin
Published: July 2020

To introduce engineering undergraduates to microstructural characterization in the scanning electron microscope, The Department of Materials Science and Engineering (MS&E) at The University of Michigan has developed the Teaching SEM. This instrument, based on a Philips XL30 SEM and located in the teaching laboratories, may be controlled from a lecture theater or classroom virtually anywhere on the University campus via a combination of the campus computing network and the campus cable television network. The use of the campus cable TV network is a limitation. Many areas of the University have Internet connections, but no cable connections. A number of local schools have expressed an interest in incorporating use of this system into their classes. The current work seeks to eliminate the cable TV network and send both the control and video signals over the Internet.
Interactive Nano Visualization for Science and Engineering Education-Scanning Probe Microscope on the Web
Authors: Ramakrishna BL , Razdan A , Sun J , Ong E , Garcia A A
Published: July 2020

The integration of nano-science and technology concepts into upper-division high school and lower-division college curricula will require innovative educational approaches that will help students understand the structures and properties of matter on a scale below 100 nanometers, i.e., the nanoscale. This Interactive Nano-Visualization in Science and Engineering Education (IN-VSEE) project will create a consortium of university and industry researchers, community college and high school science faculty, computer scientists and museum educators with a common vision of creating an interactive World Wide Web (WWW) site to develop a new educational thrust based on remote operation of advanced microscopes and nanofabrication tools coupled to powerful surface characterization methods. The centerpiece of this project is the web-based operation of the revolutionary scanning probe microscope (SPM), which has evolved rapidly into a relatively simple, yet powerful, technique capable of imaging and manipulating materials at resolutions down to the atomic scale.
Towards Sub-Ångstrom Resolution With A 200 Kv TEM By Means of a Cs-Corrector and a Computer Controlled Alignment Procedure
Authors: Haider M , Uhlemann S
Published: July 2020

One of the most difficult problems on the way to sub-Ångstrom resolution at a medium accelerating voltage of about 200 kV, the correction of the spherical aberration, has been solved. Already more than fifty years ago, Scherzer showed that the two major axial aberrations, the chromatic and the spherical aberration, can be corrected by a suitable combination of electrostatic and/or magnetic multipole elements. Due to the availability of high-coherent electron sources with a small relative energy width DE/E the necessity of correcting the chromatic aberration can be avoided.

Our solution for spherical aberration correction follows a suggestion by Rose. It is based on two electromagnetic hexapoles and four additional lenses. The principle by which correction is achieved is based on the fact that the primary aberrations of second order of the first hexapole are compensated by the second hexapole element.
Acquisition and Processing of Large Dynamic Range Digital Images
Authors: Hunt J A
Published: July 2020

Acquisition of large dynamic range information is important for optimizing the performance of SEM’s, TEM’s, and other microscopies. The majority of digital imaging performed in desktop publishing and other consumer markets today is limited to 8-bit resolution, and these technologies are often modified for use in electron microscopy (EM). The limitations of these techniques are clearly evident in many EM situations despite the fact that human visual system is not equipped to differentiate more than 2^5 gray levels. The most common case is when a user seeks to view information hidden in both the image's dark levels and in the brightest levels. If multiple images at different detection levels are required despite digital processing then the image information is being limited by the digitization resolution.

Digitization is the process of converting a signal from the analog form that originates from our microscope detectors to a digital form that is suitable for processing within computers.
Edge Sharpening For Unbiased Edge Detection in Field Emission Scanning Electron Microscope (FESEM) Images
Authors: Raj P Markondeya , Dunn Stanley M , Cannon W Roger
Published: July 2020

Mathematical representation of particle orientation and shape can show quantitative differences in particle morphology and microstructures of ceramic green bodies with apparently equiaxed powders. In this work, fourier descriptors and moment invariants were used to quantify the shape of ceramic particles and identify their orientation. Edges constitute a significant portion of the information contained in these images, and hence edge detection forms an important issue in these image processing algorithms.

A Field Emission Scanning Electron Microscope (FESEM, Leo 982) was used to collect images of various ceramic green bodies in order to assess the ceramic particle shape and orientation. The images were collected and displayed as rectangular pixels on the microscope monitor which were then stored as square pixels (square-pixel-interpolation). Application of various edge detection algorithms on the stored images show strong bias to edges in the direction perpendicular to the scanning direction.
Extracting Objects with Adaptive Segmentation Techniques: Going Beyond Intensity Thresholding
Authors: Eggleston Peter
Published: July 2020

In designing automated systems for interpretation of micrographs, it is often the goal to separate and discern various objects within the image data. After segmentation, measurements of the objects, called features, can then be calculated and used for process or statistical analysis. Simple segmentation schemes based on single threshold operations, often lack the sophistication to deal with intricate or subtle details of the image data, or require user intervention in the threshold selection process. This talk will present and discuss advanced techniques which adapt to the data, and which can operate autonomously without human supervision.

Segmentation is a process which transforms pixel based image data into symbolic descriptors representing groups of pixel elements. These descriptors are called objects and take the form of lines, regions, polygons, points, windows of interests, or other unique representations. Most laboratory image analysis software packages utilize segmentation schemes based on the principle of intensity analysis.
Digital Image Acquisition and Presentation for High Resolution SEM
Authors: Chen Ya
Published: July 2020

Images obtained from an analog SEM are traditionally viewed and recorded from a cathode-ray tube (CRT). Many laboratories use instant film (e.g. Polaroid #52, #55 instant film) to justify image quality and obtain permanent image quickly. Digital imaging provides an alternative approach for image acquisition and recording. One major advantage of digital SEM is image averaging that allows one to improve the signal-to-noise ratio (SNR) from a noisy quick-scan image to reduce charging. SEM signal yield is proportional to incident beam intensity, image acquisition time or duration of beam interaction with specimen (dwell time). The higher beam intensity, or longer the dwell time, the more signal generated. However, for high-resolution SEM imaging, the beam dose and dwell time are limited by drafting, radiation damage, and contamination. Therefore high-resolution biological SEM images invariably have poor SNR.
The Tomographic Atom Probe: A New Dimension In Material Analysis
Authors: Deconihout B , Pareige P , Blavette D , Bostel A , Menand A
Published: July 2020

Today material science requires the use of increasingly powerful tools in material analysis. The last twenty years have witnessed the development of a number of analytical techniques. However, among these techniques, only a few allow observation and analysis of materials at the nanometer level ; one can mention scanning transmission electron microscopy coupled with electron energy loss spectrometry (STEM-EELS), SIMS and atom-probe techniques. In the STEM combined with electron energy loss spectrometry the spatial resolution can be better than one nanometer on a wide scanning area. However the in-depth spatial resolution is limited by the specimen thickness and therefore strongly depends on samples preparation. On the contrary, In SIMS techniques the in-depth spatial resolution can be as good as one nanometer but the lateral resolution is set by the ion beam diameter.
Atom Probe Field Ion Microscopy of High Resistivity Materials
Authors: Sijbrandij S J , Larson D J , Miller M K
Published: July 2020

Over the last 30 years, the atom probe has proved to be a powerful tool for studying nanometer-sized compositional fluctuations in a wide range of metallic alloys but has had only limited applications to semiconductors and ceramics. One of the primary reasons for this difference is the higher resistivity of semiconducting and ceramic specimens. Because of this high resistivity, the high voltage field evaporation pulse is attenuated before it reaches the apex of the specimen thereby making the pulse ineffective for field evaporation. Experiments have demonstrated that both variants of the voltagepulsed atom probe (i.e., those instruments in which the field evaporation pulse is applied directly to the specimen and those in which the negative pulse is applied to a counter electrode in front of the specimen) are equally affected. In this overview, the limits of applicability of the voltage-pulsed atom probe to high resistivity materials are examined.
Phase Separation and Precipitation in a PH 17-4 Stainless Steel By Prolonged Aging At 400 °C
Authors: Murayama M , Katayama Y , Hono K
Published: July 2020

Precipitation-hardened stainless steels are important structural materials in a variety of industrial applications in aircraft, chemical and power plants. These steels have a combination of good mechanical properties, corrosion resistance and simple fabrication process. Precipitation reaction in a PH 17-4 stainless steel which contains approximately 3 wt.% of Cu begins with formation of coherent copper-rich precipitate, which subsequently transform to incoherent fee Cu by further aging. By prolonged aging at 400 °C, embrittlement occurs as hardening progresses. Both the coarsening of Cu and the decomposition of the martensite matrix could be the reasons for this embrittlement. Thus, this study attempted to clarify the phase separation and the precipitation processes in a PH 17-4 stainless steel on prolonged aging by atom probe field ion microscopy (APFIM), in order to understand the mechanism of the degradation of mechanical properties by long term medium temperature aging.
Apfim and HREM Studies of Nanocomposite Soft and Hard Magnetic Materials
Authors: Hono K , Ping D H , Ohnuma M
Published: July 2020

Atom probe field ion microscopy is the most suitable technique for determining local chemical composition changes during nanocrystallization processes of amorphous alloys. In this talk, we report atom probe field ion microscopy (APFIM) and high resolution electron microscopy (HREM) studies on nanocrystallization processes in Fe-Si-B-Nb-Cu soft magnet and Fe-Nd-B-Co-Ga exchange spring magnet.

Fe or Co based alloys with nanocrystalline microstructure show excellent permeability because the net magnetocrystalline anisotropy is significantly reduced when the grain size becomes smaller than the ferromagnetic exchange length. Fe-Si-B-Nb-Cu alloy is the pioneering nanocrystalline soft magnetic material invented by Yoshizawa et al. in 1988 [1]. Our previous works [2,3] reported evidence for clustering of Cu prior to the onset of the crystallization reaction. However, in the previous studies, it was not confirmed that these Cu clusters work as heterogeneous nucleation sites for a-Fe primary crystals.
Field Ion Microscopy of Multilayer Film Devices
Authors: Larson D J , Petford-Long A K , Cerezo A
Published: July 2020

Control and optimization of materials’ properties will increasingly depend on the ability to tailor both the structure and chemical composition of the materials at the nanoscale level (100 nm and less). One specific class of “nanostructured” materials is the multilayer film (MLF) structure, which is formed by alternate deposition of two or more different elements or compounds and has a wide range of applications in, for example, the field of data recording and storage. In order to understand MLF structures well enough to improve and optimize their properties, characterization at the atomic level with regard to both structure and chemistry is essential. Interface quality is one of the most important parameters due to the possibility of intermixing between layers. It is thus desirable to obtain information about the interface morphology in these materials at the highest possible resolution.
Apfim Investigation of Segregation in a Nickel Base Alloy
Authors: Thuvander M , Stiller K
Published: July 2020

Segregation of boron, carbon and nitrogen to grain boundaries in a nickel based model alloy has been investigated using atom probe field ion microscopy (APFIM). The material corresponds to a commercial alloy (Inconel 600), but contains lower levels of alloy additives and impurities. The major composition was Ni-16Cr-10Fe (wt.%). The alloy was solution annealed at 950°C for 10 min, which resulted in a grain size of 20 μ. Subsequently heat treatments for 1 h at temperatures of 550°C, 600°C and 700°C were applied. TEM investigation showed that the heat treatment at 700°C resulted in precipitation of intergranular chromium-rich carbides. The other temperatures were obviously too low and the aging times too short to cause precipitation, since carbides were not observed in the materials heat treated at 550°C and 600°C.

As the grain size was about 100 times larger than the accessible depth of APFIM analysis (≃200 nm), much care had to be taken in preparing samples containing a grain boundary close to the tip apex.
Interdisciplinary Development of Eels Compositional Mapping
Authors: Leapman RD
Published: July 2020

Historically, electron energy-loss spectroscopy (EELS) in the electron microscope has evolved from work performed in biological as well as materials science and physics laboratories. The task of developing EELS compositional imaging for biological applications has been particularly challenging for two reasons. First, biological structures are radiation-sensitive and second, elements and compounds of interest are distributed sparsely in a multi-component matrix. For example, the physiologically important element, calcium, is typically present in cells at only 10-100 atomic parts per million.3,5 Even, when individual molecular components of a cell are isolated, elemental concentrations can still be low. Thus, double-stranded DNA contains only six phosphorus atoms per nanometer of its length; and protein molecules typically contain less than 0.5 per cent sulfur. This demand for high sensitivity in biological applications has provided an impetus to improve electron optics, to develop flexible image acquisition methods and to optimize spectral processing.
Multispectral Imaging in Light Microscopy
Authors: Spring K R
Published: July 2020

Many recent applications in light microscopy involve the use of multiple fluorophores or the delineation of signals arising from spectrally distinct sources. In microspectroscopy, it is always desirable to illuminate fluorescently-labeled microscopic specimens with monochromatic light as the narrowest possible excitation wavelength range usually results in the highest emission signal-to-noise ratio. Generation of polychromatic light from an arc lamp and selection of the excitation wavelength by interference filters or monochrometers are the most common techniques for excitation microspectrofluorometry. Emission spectroscopy is usually done with filter wheels, monochrometers, or interferometers inserted between the microscope detection port and the detector. This presentation will be directed toward other, less frequently-used, approaches for spectral scanning of the specimen in the light microscope. Three topics will be considered: 1) the use of acousto-optical tunable filters and lasers for rapid, narrow-band, excitation wavelength selection; 2) the use of holographic notch filters for rejection of unwanted excitation laser light; 3) using liquid-crystal tunable filters for emission scanning.
Quantitative Energy-Filtering Transmission Electron Microscopy (EFTEM) In Materials Science
Authors: Hofer F , Grogger W , Warbichler P
Published: July 2020

Equipping a transmission electron microscope with an energy-filter offers extraordinary advantages for the characterization of both materials science and biological samples. Besides improvements for TEM imaging and electron diffraction like better contrast and resolution, elemental mapping using inner-shell ionizations has become the main application of EFTEM. Elemental maps with resolution down to 1 nm and elemental sensitivities down to a single monolayer have been reported. Using a Philips CM20 equipped with a Gatan Imaging Filter (GIF) for our experimental work, we acquired elemental maps with the three window method (A.E-1r background extrapolation from two pre-edge windows) and jump ratio images (division of post-edge image by a pre-edge image). One important application of EFTEM is the detection of secondary phases in materials e.g. precipitates and grain boundary phases. For example, fig.la shows the TEM-image of a 10%Cr steel with the secondary phases mostly invisible.
Transmission Electron Holography of a GaN/AlxGal-xN Heterostructure
Authors: Wang YC , Kisielowski C , Nelson E C , O’Keefe MA
Published: July 2020

GaN and the related AlN semiconducting materials have recently attracted considerable attention because of their versatile applications for optoelectronics. Large stresses are present in the GaN/AlN thin-film heterostructure and can exceed GPa's. They originate from a large lattice mismatch between the substrate(sapphire)/GaN (14%) and the AlN/GaN interface (-2.7%) in quantum well structures. The strain is expected to induce local piezoelectric fields in these polar materials. It is essential for a further development of GaN based thin films to fully understand the formation and the local strength of these fields. Previous studies show that there are unusual large fluctuations of the patterns in lattice images present across GaN/AlxGa1-xN and GaN/InyGa1-yN quantum wells. They are attributed to compositional fluctuations and have been studied by quantitative high resolution electron microscopy. Differences between the strain profiles and the electrostatic (scattering) potential profiles were observed.
Compositional Characterization of an O-N-O Layer in a Dram Using FE-(S)TEM And EELS
Authors: Kawasaki M , Oikawa T , Ibe K , Park K H , Shiojiri M , Kersker M
Published: July 2020

An O-N-O layer within a DRAM is designed to be an insulator between a single-crystal silicon substrate and a poly-crystalline silicon gate. The nominal structure of the layer is SiO2-Si3N4-SiO2. It has been reported that oxygen and nitrogen diffuse into each other layer while preserving the three layered structure. In order to measure the elemental distribution quantitatively, EELS was used for Si and light elements O and N in this study.

The specimen was cut from a 16M-DRAM device and prepared for TEM observation by the crosssection ion milling method. The O-N-O layer was analyzed using a JEM-201 OF FE-(S)TEM equipped with a scanning imaging device including a High-Angle Annular Dark Field(HAADF) detector which is capable of collecting electrons scattered 50 to 110 mrad, and also a PEELS(GATAN model 676). Fig. 1 shows a HAADF image of the O-N-O layer.
EFTEM and STEM EELS Spectrum Imaging
Authors: Hunt J A , Harmon R H
Published: July 2020

Electron energy-loss spectroscopy (EELS) in the transmission electron microscope (TEM) is a powerful technique that analyzes the inelastic scattering distribution of the fast TEM electrons after they have lost energy within the sample. The resultant energy-losses are characteristic of elemental, chemical, and dielectric properties and are typically measured in one of two ways. Parallel-detection EELS spectrometers (PEELS) acquire spectral data over a large range of energy-loss simultaneously for rapid acquisition of spectral data at a single point. In contrast, the energy filtering TEM (EFTEM) acquires only a single energy band at once, but does so for thousands or even millions of image pixels simultaneously.

Spectrum-imaging concerns the acquisition of spectroscopic data of sufficient detail for rigorous analysis at each pixel in a digital image. (Fig. 1) A STEM EELS spectrum image “data cube” can be acquired by stepping a focused electron probe to each pixel and filling the spectrum image one spectrum at a time.
History and Cross-Disciplinary Perspective of Compositional Imaging and Mapping With Nexafs Microscopy
Authors: Ade H
Published: July 2020

In Near Edge X-ray Absorption Fine Structure (NEXAFS) microscopy, excitations of core electrons into unoccupied molecular orbitals or electronic states provide sensitivity to a wide variety of chemical functionalities in molecules and solids. This sensitivity complements infrared (IR) spectroscopy, although the NEXAFS spectra are not quite as specific and “rich” as IR spectra. The sensitivity of NEXAFS to distinguish chemical bonds and electronic structures covers a wide variety of samples: from metals to inorganics and organics. (There is a tendency in the community to use the term NEXAFS for soft x-ray spectroscopy of organic materials, while for inorganic materials or at higher energies X-ray Absorption Near Edge Spectroscopy (XANES) is utilized, even though the fundamental physics is the same.) The sensitivity of NEXAFS is particularly high to distinguish saturated from unsaturated bonds. NEXAFS can also detect conjugation in a molecule, as well as chemical shifts due to heteroatoms.
Interfacial Segregation and Concentration Profiles by Energy-Filtered Transmission Electron Microscopy: Issues and Guidelines
Authors: Bentley J
Published: July 2020

Over the several years that imaging energy filters have been available commercially, numerous and wide-ranging applications have demonstrated elemental mapping at resolutions approaching 1 nm. From reviewing applications of energy-filtered transmission electron microscopy (EFTEM) to interfacial segregation and concentration profiles in metals and ceramics, some guidelines and issues may be identified. The work has been performed with a Gatan imaging filter (GIF) interfaced to a Philips CM30 operated at 300 kV with a LaB6 cathode.

For quantitative elemental mapping by EFTEM a number of interrelated parameters [field of view, resolution, collection angle (β), slit width (Δ), incident beam divergence (α), illumination uniformity, probe current (i), drift rate, exposure time (T), and local specimen thickness (t)] have always to be properly selected and controlled. For example, the collection angle should be large enough for a strong signal, but not so large that the signal/background (S/B) and chromatic-aberration-limited spatial resolution (δ) are both degraded.
Going Nondispersive
Authors: Heinrich Kurt F J
Published: July 2020

In February 1968 Ray Fitzgerald, Klaus Keil and myself published in Science a communication titled “Solid-State Energy-Dispersion Spectrometer for Electron Microprobe X-ray Analysis”. The authors describe the use of a lithium-drifted silicon detector for the direct identification of x-rays, without a diffracting crystal, in an electron probe. The subject of this paper was to modify profoundly the development of x-ray microanalysis in the years to follow.

Pulse-height analysis of gamma rays detected in scintillation counters was widely used at the time. For radiation of energies below 30 keV, gas proportional counters were also employed. In elementary analysis by x-rays the poor energy resolution of these detectors limited the application of such a procedure, although single-channel pulse height analysis was employed as an adjunct to crystal spectrometers.

In 1951, Raymond Castaing in his thesis described his invention of the electron probe microanalyzer, created by adding to a transmission electron microscope a curved-crystal spectrometer which focused the x-rays emitted by the specimen into a Geiger-Muller counter.
Low Voltage X-Ray Microanalysis of Bulk Bio-Organic Samples
Authors: Echlin Patrick
Published: July 2020

Although high resolution (2nm), low voltage (lkV), SEM of bio-organic materials can now be performed more or less routinely using instruments fitted with a field emission source, virtually no low voltage x-ray microanalysis has been carried out on this type of specimen. Boyes and Nockolds showed that quantitative microanalytical information could be obtained from polished inorganic samples at a spatial resolution of l00nm at 5kV and Johnson et al obtained similar type of data at a spatial resolution of 150nm at 3kV. High spatial resolution (l0nm) microanalysis can be achieved in frozen dried or chemically compromised sections of biological material examined at high voltage in the TEM but frozen hydrated chemically unfixed sections are damaged. The other approach is to use the SEM with frozen hydrated, chemically uncompromised samples, usually at about 10-15kV, in order to obtain sufficient signal from the elements of interest which typically lie in the range Na (Z=l 1) to Ca (Z=20).
EDS of thin Biological Specimen in the Study of Time-Dependent Physiological Processes
Authors: Wendt-Gallitelli MF , Voigt Tilman , Schultz Michael , Rudolf Frank , Isenberg Gerrit
Published: July 2020

The contraction of muscle depends on the ability of intracellular organelles to rapidly release and take up large amounts of activator calcium. In cardiac muscle the intracellular sodium concentration is known to also modulate this Ca2+ release: Na+-Ca2+ exchange creates narrow cytosolic microdomains just internal to the sarcolemma (approximately 20 nm wide) with locally elevated concentrations of Ca2+ and Na+. The existence of such “functional” compartments with transient high ionic concentrations has been postulated for explaining the nigh efficiency of signal transmission during excitation-contraction coupling. We present results showing that electron probe microanalysis (EPMA) at the high spatial resolution of scanning transmission electron microscopy (STEM) can detect changes in sodium and calcium concentration of membrane-limited organelles and functional microdomains provided the cardiac myocytes are rapidly frozen at defined times during activation of contraction.
“Standardless” Quantitative Analysis by Electron-Excited Energy Dispersive X-Ray Spectrometry: What is its Proper Role?
Authors: Newbury Dale E
Published: July 2020

The development of energy dispersive x-ray spectrometry (EDS) has had a profound impact on the methodology of quantitative x-ray microanalysis of thick specimens (i.e., thickness≫ electron range) as performed in electron beam instruments. By equipping the scanning electron microscope (SEM) with EDS, quantitative x-ray microanalysis has become commonly available to a wide range of users, at least some of whom have only a modest background in analytical science. An important aspect of the development of quantitative analysis by EDS has been the extensive analytical experience gained during the development of the electron probe microanalyzer (EPMA) equipped with wavelength dispersive x-ray spectrometers (WDS). The critical measurement step for quantitative WDS analysis was recognized to be the determination of the “k-value”:

k = Iunk / Istd (1)

where I is the measured characteristic intensity of a specific x-ray peak, corrected for background and peak overlaps, for both the unknown and the standard.
Multivariate Statistical Analysis of Particle X-ray Spectra
Authors: Anderson Ian M , Small John A
Published: July 2020

Multivariate statistical analysis (MSA) is a powerful tool for the analysis of series of spectra. This paper explores an application of MSA to a series of energy dispersive X-ray (EDX) spectra acquired in the scanning electron microscope (SEM) from a series of particles. The raw data were series of spectra previously acquired to test analytical procedures for trace element detection. This paper explores the possibility of performing the trace element detection with MSA components that have been extracted from the raw data without any a priori assumptions about the information content of the particle spectra. Particles were prepared from two analytical glasses, dispersed onto carbon substrates and coated with carbon. The compositions of the two glasses are substantially similar, except that one glass (K-3106) contains 0.7 wt.% Fe, whereas the other glass (K-3069) does not contain Fe at a detectable level.
Extracting Chemical Information From Energy-Dispersive X-Ray Spectra by Multivariate Statistical Analysis (MSA)
Authors: Saunders M , Menon ESK , Chisholm DJ , Fox AG
Published: July 2020

The introduction of Multivariate Statistical Analysis techniques such as Principal Component Analysis (PCA) to the study of EDS and EELS spectra has opened up new possibilities for processing spectral data. In conventional EDS analysis each spectrum provides information about the elemental composition of the sample at a specific probe position. Where the signal arises from a single phase this elemental composition corresponds to the chemical composition of the phase. However, where the probe is incident on a multiphase region of the sample it is impossible to make a direct identification of the different chemical phases contributing to the overall spectrum.

With PCA it is no longer necessary to consider the spectra as isolated pieces of information. It is now possible to analyze a series of spectra as a single entity, looking for correlations between the variations in the elemental signals present in the individual spectra.
Statistical Consideration in EDS Microanalysis
Authors: Lifshin Eric
Published: July 2020

The overall precision of electron microprobe measurements has not been studied extensively. It is often only described in terms of the precision of individual x-ray measurements or worse yet by relying on some rule of thumb based on historical experience. This is unfortunate because the analyst is expected to determine whether his or her measurements can distinguish between two samples or if a particular component can be detected above background or in the presence of other elements. Thus precision is at the heart of establishing composition/structure/property relationships and clearly deserves more attention.

There are many sources of variability encountered in determining composition whether using energy dispersive (EDS) or wavelength dispersive (WDS) spectrometery. These include Instrumental Variables, i.e., beam voltage and current, specimen position and orientation, detector position, and measurement electronics; Specimen Preparation, i.e., how representative the sample is of the problem to be solved, specimen preparation and contamination, and quality of standards; Data Processing, i.e.,
Trace Element Quantitation in Biological X-Ray Microanalysis
Authors: Leapman RD , Swyt-Thomas CR , Agoston D v , Pivovarova N , Andrews SB
Published: July 2020

In high-resolution biological energy-dispersive x-ray (EDX) microanalysis it is often necessary to measure very low elemental concentrations. As an example, calcium, a physiologically important element, typically occurs in subcellular compartments at concentrations of 10-100 atomic parts per million (corresponding to 1-10 millimole/kg dry weight of sample) and it is ultimately desirable to measure the concentration of this element with a standard error of ±1 atomic ppm (or ± 0.1 millimole/kg). Detection of calcium in biological specimens is further complicated by the presence of relatively high levels of potassium (around 0.5 atomic % or 500 millimole/kg), which gives rise to overlap of the K Kβ and Ca Kα peaks in the EDX spectrum. Counting statistics are frequently the limiting factor for detectability, but this is not necessarily the case because in the analytical electron microscope it is possible to collect spectra for long periods using a high probe current.
K-Factor Standards for Low-Z Quantification
Authors: Egerton Ray , Malac Marek
Published: July 2020

Although elements of low atomic number (Z<11) are detectable in TEM specimens using a modem energy-dispersive (EDX) detector, quantification remains a challenge. Problems include the large absorption corrections needed for specimens of typical thickness and the need for calibration specimens which provide k-factors appropriate to a particular detector/window arrangement. We have addressed this second problem by fabricating thin films containing several light elements in combination with silicon, which typically acts as the reference element when specifying k-factors.

Because the EDX peaks of adjacent light elements overlap considerably, it is preferable to have two specimens: one containing C, O and Si, the other B, N, F and Si. We have used both e-beam evaporation and sputtering techniques to deposit thin films on a substrate which can later be removed to leave a freestanding film mounted on a TEM grid.