bluuebunny/crossref_metadata_2025 huggingface dataset:
Modified Flat-BED Scanner for Macroscopic Study of Large Specimens
Authors: Cheng Wayne Y , Cheng Ping-chin , Cheng Mai-Ing , Walden David B
Published: July 2020

The field number of the objective lens limits the field of view in a conventional compound microscope; even at very low magnification, the microscope does not allow observation of large pieces of specimen at once. This made the observation of organs and large pieces of tissue sections inconvenient. in the course of studying the development of maize stem, we encountered the need of digitizing large hand sections for 3D reconstruction. Splicing a series of images that are taken at different positions to form a montage is not acceptable, because the jointed image suffers from mismatch due to lens distortion. Considering the resolution needed in our study, one alternative is to use a consumer flatbed scanner designed for a personal computer. in order to adapt the conventional scanner for wet tissue scanning, an Acer 620TPC flatbed scanner, equipped with a trans-illuminator, was modified (FIG 1).
The Role of Microscopy in Quality Control, Litigation and Forensic Studies of Hides, Skins and Leather
Authors: Cross Robin H
Published: July 2020

The economic importance of animal hides and skins as the source material for the natural leather industry is significant world-wide, and in some countries of the developing world the livelihood of a large proportion of the population depends upon it. Consequently, it is understandable that anything affecting the quality of the source material and the finished product has major economic, industrial and sociological significance. It is also inevitable that a product that is so widely-used in many ways by most of the population will become an important source of evidence in forensic investigations.

Quality control procedures in the leather industry involve monitoring the progress of the hides and skins from the growth stages of the animal, through the slaughter, storage, transportation, curing, tanning and finishing processes, to the sale and distribution of the finished product. There are many factors during these stages that can affect quality of finished leather, amongst the most important of which are mechanical and parasite damage during growth, biodeterioration and mechanical damage between slaughter and curing, mechanical, heat and chemical damage during curing, tanning and finishing.
Characterization of Biodegradation of Fiber Cement Shingles by Scytonema Sp. Using Optical and Scanning Electron Microscopy
Authors: Reine Barbara A , Murphy Colin
Published: July 2020

Fiber cement roofing shingles from condominiums in Hawaii were examined for deterioration using optical and scanning electron microscopy. The product has a 50 year warranty and had been in service since 1994. Shingle samples were taken in August and September, 2000 after a growing volume of reports of roofing deterioration were received by the condominium association. Close-up visual inspection confirmed that the roof areas showing deterioration were covered with a black growth. Roofing samples from areas exhibiting deterioration, areas with no deterioration, and new material were compared by microscopy.

Examination of the black growth by optical microscopy revealed it to be primarily the Cyanobacterium, Scytonema sp.This is a filamentous organism found from the Arctic to the Antarctic, and is common to Oahu and Maui.’ Other organisms observed to be present are Chroococus sp., Gloeocapsa sp., Aphanocapsa sp., Oscillatoria sp.,a very few Trebouxia sp.and lichens.
Tem of Beo Aerosols: Materials Aspects of Method Development in Studying Chronic Beryllium Disease
Authors: Dickerson Robert M , Scripsick Ronald C , Day Gregory A , Stefaniak Aleksandr B , Peterson Eric J
Published: July 2020

The present work is a small portion of a multi-disciplinary science-based study of the physicochemical properties of respirable aerosols containing beryllium. The working hypothesis is that Chronic Beryllium Disease (CBD) is by controlled dissolution of Be particles in the lung. Recent studies have shown correlations between specific Be production processes and the development of Be sensitivity and CBD. in Beryllium Oxide (BeO) production, 9.8% of the workers develop a sensitivity to Be and 4.9% develop CBD. in vitro cellular dose-response relations have been observed for BeO particles.

This study involves a characterization of BeO materials sampled from the air stream around the production process at Brush Wellman Inc. (Elmore, OH) and laboratory-prepared BeO. One purpose of this work is to determine if lab-prepared material is a good surrogate for the process-generated aerosols for cellular dissolution studies. Both materials were size-separated into six fractions using a five-stage cyclone followed by a electrostatic precipitator (ESP).
Electron Beam Irradiation Induced Structural Modulation and Damage in GaN Nano Crystals
Authors: Sun HP , Li H , Li HD , Zou GT , Zhang Z , Pan XQ
Published: July 2020

GaN is a semiconductor material with promising applications in display and laser devices. GaNbased thin films have been grown by various methods and intensively investigated. Additionally, GaN nano particles have been prepared by various different methods. in this paper, we report our new finding of the structural modulation of GaN nano crystals induced by electron beam irradiation within a transmission electron microscope (TEM). The origin of the modulation structure is due to the ordering of N vacancies in the GaN nano crystals.

The GaN nano crystals were prepared by d.c arc plasma method. A Philips CM200 TEM with a field emission gun (FEG) operating at 200KV was used in this study. The GaN nano crystals normally show hexagonal shape (see Fig.la). Corresponding electron diffraction pattern along [0001] axis indicates the Wurtzite structure (see Fig. lb). It was unexpected that satellite reflections gradually appeared in the diffraction pattern after the GaN nano crystal had been exposed to the electron beam (see Fig.lc-d).
Characteristic Morphology and Its Properties of Melt-Crystallized Polyethylene Banded Spherulites on Scanning Electron Microscope
Authors: Park Jemyung , Eom Kyuyoung , Kwon Ohjun
Published: July 2020

In spite of commercial importance of polyethylene(PE), morphologies of melt crystallized PE have been rarely studied. Although, it was possible to observe polyethylene microstructure, they were based on the observation performed almost exclusively on thin films which were obtained either by casting samples between glass plates, or by microtoming the materials with transmission electron microscope(TEM). Despite the usefulness of TEM for detailed investigation of the polyethylene, it is not suitable for the structure characterization of the bulk samples, for examples, the characterization of a thick testpiece and commercial products of polyethylene itself. For such bulk specimen or thick sample, scanning electron microscope (SEM) is more useful, if the appropriate and reliable sample preparation method is applied.

In this study, we introduce a chemical etching technique for the investigation of melt crystallized polyethylene microstructure by SEM. Especially in this work we studied the characteristic properties and shapes of polyethylene banded spherulite which come from the melt s.
Nucleation of Intragranular Accicular Ferrite in a Ti-Containing Low Carbon Steel of High N Content
Authors: Jin Hyoung-Ha , Shim Jae-Hyoek , Cho Young Whan , Oh Kyu Whan , Lee Hu-Chul
Published: July 2020

Formation of acicular ferrite grains by dispersing non-metallic inclusions which can act as intragranular nucleation sites within austenite grain is proposed as a method to obtain refined grain structure in steels. The microstructure of acicular ferrite steel consists of fine interlocking ferrite plates nucleated on dispersed non-metallic inclusions. This acicular ferrite structure provides a desirable combination of high strength and good toughness because of its small plate thickness and interlocking microstruture. in Ti-containing low carbon steels, researchers proposed that Ti2O3 or MnS, among inclusions, is the most effective nucleant for intragranular ferrite because of the formation of Mn depleted zone(MDZ) around Ti2O3 or MnS particles. TiN is also reported as a nucleation site owing to the coherency between ferrite and TiN crystals. But It has not been a simple task to identify which inclusions and what mechanisms are really effective in the formation of intragranular acicular ferrite.
Local Halide Distributions in High-Speed Tabular Ag(Br,I) Emulsion Microcrystals by Cryo-FEG-AEM
Authors: Oleshko V , Crozier P , Garone L , Freedman J
Published: July 2020

The unique physical and chemical properties of AgX (X=C1, Br, I) emulsion microcrystals (optical, solid state, transport, chemical and spectral sensitizations and development) account for their use as basic light quanta detectors in practical photography for over 150 years. in spite of the advances made in other recording systems, especially in electronic imaging, contemporary AgX-based photographic materials are still superior in sensitivity and resolution. Although the replacement of AgX-based imaging systems by electronic imaging was already predicted 20 years ago, their current world manufacturing level is now larger than ever. However, in order to be successfully incorporated into digital and hybrid information technologies for the new Millennium, AgX-based photographic materials should further improve their quantum efficiency and image quality. in order to achieve these objectives, the key components should be intentionally modified with a focus primarily at the nanostructural level.
Is a TEM for “Real World” Application Available Presently?
Authors: Probst W , Benner G , Kabius B , Lang G , Hiller S , Seybold V , Zellmann E
Published: July 2020

Transmission electron microscopes have been built along with and guided by technological opportunities since the last five decades. Even though there are some “workhorse” type of microscopes, these instruments are still more or less built from the technological viewpoint and less from the viewpoint of ease of use in a wide range of applications. On the other hand, leading edge applications are the drivers for the development and the use of leading edge technology. The result then is a “race horse” which is of very limited benefit in “Real world”.

During the last decade computers have been integrated to build microscope systems. in most cases, however, computers still have to deal with obsolete electron optical ray path designs and thus, have to be used more to overcome the problems of imperfect optics and bad design of ray paths than to provide optimized “Real world” capabilities.
Scanning Microscopy of Wax Removal from Bioscoured Cotton Textiles
Authors: Boylston Eileen K , Ingber Bruce G , Lambert Allan H , Hruska Zuzana , Yachmenev Valeriy G
Published: July 2020

The cotton textile fiber is a field dried, single cellular, collapsed convoluted tube. It is covered with waxes, which are connected by ester linkages to pectins enmeshed in a basket weave structure of the cellulosic primary wall. Depending upon its variety, the mature cotton fiber contains between 0.5%and 1% wax by weight, and it is practically waterproof. The normal industrial method for cleaning cotton fabric involves three steps: de-sizing with amylase enzymes to remove starch sizing or boiling in an aqueous surfactant solution to remove polyvinyl alcohol (PVA) sizing; scouring with caustic soda to remove waxes; and bleaching with hydrogen peroxide to obtain uniform whiteness. The effluent from this process is environmentally toxic, but the process is necessary to prepare fabric for dyeing, durable press finishing, etc. Current research is directed towards the investigation of environmentally friendly methods of removing cotton waxes.
Growth of Oxygen Precipitates in Low-Dose Low-Energy Simox
Authors: Jeoung Jun Sik , Johnson Benedict , Seraphin Suṗapan
Published: July 2020

Silicon-on-insulator (SOI) is becoming a key technology for low power electronics due to substantially reduced power consumption of electronic components, and a capability of compact circuit design which are not readily achievable in bulk silicon technology [1]. Separation by IMplantation of OXygen (SIMOX) is the most promising technology for fabricating SOI material. The basic SIMOX process consists of implantation of oxygen into the single crystalline silicon wafer and the subsequent high temperature annealing. Oxygen implantation at low doses does not form a continuous buried oxide (BOX) layer but leads to an inhomogeneous distribution of the oxygen precipitates during implantation process. The formation and growth of oxygen precipitates in low-dose SIMOX depend strongly on the implantation conditions such as oxygen dose, implantation temperature, annealing temperature and ramping rate [2,3]. During the subsequent annealing, Ostwald ripening of the precipitates takes place and the larger precipitates grow at the expanse of small ones until they coalesce to the buried oxide layer.
Three Dimensional Mask Metrology by Off-Axis Electron Holography
Authors: Frost Bernhard , Joy David C
Published: July 2020

Even though all real objects are three dimensional, imaging and metrology performed by using electron-beam tools such as scanning electron microscopes is inherently two dimensional. Any information about the third dimension must therefore be obtained by inference, or by time consuming special methods such as stereo-photogrammetry. If, however, the structures of interest are thin enough to be electron transparent then quantitative three dimensional metrology can be performed directly by using off-axis transmission electron holography. Here we demonstrate the application to a SCALPEL lithography mask which consists of chromium lines on a silicon support film. The off-axis holography was performed in a field emission transmission electron microscope, a Hitachi HF2000 operated at 200keV. The sample is positioned so that half the beam passes through the specimen while the rest travels only through the vacuum. An electrostatic biprism then recombines these two components to form the hologram which is recorded onto a CCD camera.
Overexpression of RHO Inhibitor and PAK as Possible Treatments For Restoring Sharp Features in Cancer Cells
Authors: C. A. Heckman , J. M. Urban , T. S. Wales , M. L. Cayer , J. A. Barnes , V. Sverdlov , C. Hall , R. Kozma , L. Lim
Published: July 2020

The mechanism of action of the tumor promoter, phorbol 12-myristate 13-acetate (PMA), depends on its ability to substitute for an endogenous second messenger, diacylglycerol, and thereby activate certain members of an enzyme family known as protein kinase C. Previous work from this laboratory showed that the quantitative shape phenotype of cells treated with PMA resembled the phenotype of bona fidecancer cells. The effect of PMA on this phenotype was transient, and was restricted to a period of two- to five-hours after exposure to PMA. When the shape phenotype was dissected into components by relating different variable's values to shape features, several of the altered values appeared to rely upon a declining number of sharp features, such as filopodia and microspikes, at the cell edge.

Filopodia and microspikes are in turn regulated by a GTPase of the Rho family, Cdc42, which modulates actin architecture.
Autofluorescence and Apoptosis in Flow Cytometry: Correlative Methods for Fluorescence and Confocal Microscopy
Authors: Smith R W
Published: July 2020

Flow cytometry offers several advantages in evaluating cellular fluorescence and separating values from chemical probes or transfected fluorescent proteins from autofluorescence. Autofluorescence can introduce artificial values that cannot be separated by examination of the fluorescence histogram. Often a comparison of fluorescence in two detectors can separate autofluorescence from positive fluorescence. A region can be defined around the cells of interest for further statistical evaluation or for subsequent sorting.

Autofluorescence is also correlated with apoptosis in that apoptotic cells often increase autofluorescence values. A clear separation of living cells from dying cells can be achieved by the introduction of a DNA stain, such as 7AAD, which will penetrate cells with disrupted or damaged cellular membranes. Intact living cells will not show the 7AAD fluorescence.

This separation is important in transfected fluorescent protein studies, as the transfection process is often toxic to cells.
Non-Invasive Imaging Technologies in Drug Safety Evaluation: Using Magnetic Resonance Imaging in Rats to Assess Theophyline-Induced Testes Toxicity
Authors: Tengowski MW , Hedlund LW , Guyot DJ , Burkhardt JE , Johnson GA
Published: July 2020

Non-invasive imaging technologies such as magnetic resonance imaging are commonly used in clinical practice. in an experimental setting, it is possible to decrease field of view and pixel size, thereby increase image resolution. We tested this magnetic resonance microscopy (MRM) technique in a theopln lline-induced rat model of reproductive toxicity. The goal of this work was to study the sensitivity of MRM to detect or predict changes in tissue proton (i.e. water) characteristics, and confirm those findings with histology.

Male Sprague-Dawley rats were fed either a control or theophylline (1.3-dimethylxanthine. 8000 ppm) diet. Experimental groups of days 8. 16. 24. and 32 animals were imaged with MRM (Figure 1) and tissue morphology confirmed with histology (Figure 2).

Tl-weighted images (with and without gadolinium-DTPA contrast. Magnevist®) and T2-weighted images were acquired at 2 T (spin-echo multislice images. 100 μm2 pixel. 300 μm slice thickness).
Distribution of Low-Density Lipoprotein in the Aortic Intima of Hyperglycemic Rats
Authors: Lee S H , Kao C H , Yang V C
Published: July 2020

Chronic hyperglycemia is a common feature of all forms of diabetes mellitus and may contribute greatly to the increase in the incidence of atherosclerosis. It has been demonstrated that increasing arterial permeability to the macromolecules can cause low-density lipoproteins (LDLs) to infiltrate and accumulate in the intima. This event is crucial for developing the plaques in the arterial wall. in this study, we use Evans blue to study the permeability of arterial endothelium in the streptozotocin (STZ)-induced hyperglycemic rats. We also use colloidal gold-labeled LDL to investigate in situ the distribution of LDL in the aortic intima of hyperglycemic rats.

The hyperglycemia was induced in male Sprague-Dawley rats (7 weeks) by a single intraperitoneal injection of streptozotocin (60 mg/kg). The blood glucose concentration and hemoglobin glycation were measured once in every week. The uptake of drinking water is monitored in the regular time interval. After 3 months into the experiment, ten hyperglycemic and control rats were anesthetized.
Accuracy and Precision f Quantitative X-Ray Microanalysis in the Environmental Scanning Electron Microscope (ESEM)
Authors: Carlton Robert A , Lyman Charles E , Roberts James E
Published: July 2020

This paper presents the results of studies concerning the accuracy and precision of x-ray microanalysis (EDS) in the environmental scanning electron microscope (ESEM). The ESEM is distinguished by its use-of gas in the microscope specimen chamber for imaging and for charge neutralization. Previous work on EDS-ESEM has concentrated either on qualitative x-ray microanalysis or on correction methods to the enlarged x-ray spatial resolution due to the electron skirt. Recent work shows that quantitative analysis is possible once charge neutralization can be accomplished in practice.

Accuracy and precision were evaluated in the work presented here using NIST SRM 482 (goldcopper alloys) and NIST SRM K411 (glass beads). The gold-copper alloy wires were prepared by mounting them in epoxy mounts and polishing to a metallurgical finish. The glass spheres were prepared by sprinkling a small amount of the sample onto double-sided carbon tape mounted onto an aluminum SEM stub.
X-Ray Microanalysis with Penelope
Authors: Salvat F , Sorbier L , Llovet X , Acosta E
Published: July 2020

Monte Carlo simulation is a suitable tool for the numerical generation of x-ray spectra by electron beams and, more specifically, for the quantification in electron probe microanalysis (EPMA). in this communication we describe the application of the general-purpose code PENELOPE to EPMA. This code simulates electron-photon showers in complex material structures consisting of homogeneous regions of arbitrary composition limited by quadric surfaces. It is devised to cover a wide energy range (from ∼500 eV to about 1 GeV). The interaction models implemented in PENELOPE are based on the most reliable information available. They combine results from first principles calculations (this is the case, e.g., for electron elastic scattering, photon Compton scattering), semiempirical models (in electron inelastic scattering) and information from evaluated data bases. to facilitate the random sampling, the cross sections of various interaction mechanisms are described through analytical expressions, which are adjusted to yield accurate values of relevant transport properties (mass attenuation coefficients, transport mean free paths, stopping powers,... ).
Evaluation of Corrections for X-Ray Microanalysis in the ESEM
Authors: Carlton Robert A , Lyman Charles E , Roberts James E , Gauvin Raynald
Published: July 2020

A number of methods have been proposed to correct for the electron beam scattering effects on xray microanalysis in the environmental scanning electron microscope (ESEM). This paper presents an evaluation of two of these methods. The Doehne method is based on the observation that x-ray counts due to the unscattered electron beam increase with decreasing chamber pressure whereas the inverse is true for x-ray counts due to scattered electrons. The x-ray count intercept, at zero pressure, of the regression lines relating x-ray counts to chamber vapor pressure is an estimate of the high-vacuum intensity. The Gauvin method is based on the relationship between x-ray counts and the fraction of the electron beam that is unscattered, fp.The fraction of the unscattered beam is calculated using an equation derived from scattering theory and uses the accelerating voltage, the gas path length, and the chamber vapor pressure.
Using a Polycapillary Optic as a Spatial Filter to Improve Micro Xray Analysis in Low-Vacuum and Environmental SEM Systems
Authors: Gao Ning , Rohdeb David
Published: July 2020

An inevitable consequence of the presence of the gas in the sample chamber of a low-vacuum scanning electron microscope (LV-SEM) and environmental SEM (ESEM) is the electron beam broadening due to the scattering in the gas. The electron broadening has a large impact on x-ray analysis because the fluorescent characteristic x rays generated far from the center of the electron probe form a high background, which reduces the detection sensitivity of x-ray analysis and degrades the x-ray image contrast. We report in this paper of using a polycapillary focusing x-ray optic between the sample and the energy-dispersive spectrometer as a spatial filter to filter out unwanted x-rays generated far from the specimen. As a result, the x-ray image contrast and the detection sensitivity of the system were notably improved.

A polycapillary focusing optic collects a large solid angle of x rays from an x-ray source of small area at its input focus, guide them through the curved channels by multiple external total reflections, and focus them to the output focus.
Diagnostics for Assessing Spectral Quality for X-Ray Microanalysis in Low Voltage and Variable Pressure Scanning Electron Microscopy
Authors: Newbury Dale E
Published: July 2020

There is increasing interest in performing x-ray microanalysis of uncoated insulators while operating in unconventional SEM operating modes such as “low voltage” scanning electron microscopy (LVSEM), where the accelerating voltage is ≤ 5 kV and the pressure is low (<10-4 Pa), or variable pressure environmental SEM (VP-ESEM), where a selected gas is maintained at pressures in the range of 1 Pa -1000 Pa. LVSEM and VP-ESEM as microscopy techniques have proven to be extremely successful for imaging uncoated insulators through various charge dissipation mechanisms that are not available under conventional SEM operating conditions (accelerating voltage ≥ 10 kV and pressure < 10-3 Pa). in LVSEM, surface charging of insulators can often be controlled by careful choice of the accelerating voltage, sample tilt, and scan rate, while in VP-ESEM the charged species in the relatively dense gas (ions, secondary electrons) form a self-neutralizing plasma to provide an additional route for discharging the specimen.
Automated Analysis of X-Ray Spectrum Images from the SEM: A Practical New Tool for Microanalysis
Authors: Kotula P G , Keenan M R
Published: July 2020

It is a conundrum that faces microanalysts every day: how do you comprehensively survey the chemistry of a microstructure in a reasonable time? Traditional solutions in the SEM would include taking an image and then collecting x-ray spectra from a series of points. This method relies heavily on the operator’s ability to identify chemically distinct regions. in addition, for a complex microstructure, this could take a considerable amount of time to do correctly. On the positive side, if care is taken, these ‘point spectra’ can be readily quantified. An alternative method that has been used widely is x-ray mapping, where a window of intensity in the spectra is integrated and displayed as an image. This has the advantage that qualitative elemental distributions from an area of a microstructure can be visualized. The disadvantages are that maps are generally not quantitative, can be susceptible to artifacts, and rely on fore knowledge of the elements to map.
Electron Microprobe Mapping as a Tool in Ilmenite Characterisation
Authors: MacRae Colin , Wilson Nick , Pownceby Mark
Published: July 2020

The demand for accurate mineralogical data is increasing rapidly as exploration methods, prospect evaluation procedures and metallurgical optimisation studies become more sophisticated. in response to these needs, semi-automated and automated image processing systems which detect minerals using optical microscopy, scanning electron microscopy or electron microprobe microanalysis (EPMA) are becoming increasingly important tools in the exploration, mining and mineral processing industries. CSIRO Minerals has developed an EPMA based imaging (or mapping) method for characterising ilmenite concentrates. The method uses a JEOL 8900R EPMA to collect elemental x-ray maps which are then processed using in-house developed software, Chimage. The mapping procedure differs from traditional automated identification systems in that no detailed a priori knowledge of the mineral phases is required. in addition, Chimage software enables complete processing and interpretation of the data set off-line. Elemental data can be displayed in either scatter or ternary diagrams showing clusters which allow mineral phases to be identified.
Mixing Tandem Cryo-Hrsem and Cryo-Stem Images of Cells and Macromolecular Assembles
Authors: Apkarian RP
Published: July 2020

Creating contrast of unstained frozen hydrated cells and isolated macromolecules in order to provide high fidelity recordings present several difficulties and therefor require attempts to maximize image information for characterization purposes. Adobe Photoshop 5.0 was employed to overlay (“layer“) topographic high resolution secondary electron (SE-I) images (HRSEM) onto STEM images with and without polarity reversal employed during digital image acquisition. Cells and molecular samples precipitated from an aqueous droplet or aerosol and supported on carbon and holey carbon coated grids were plunge frozen and Chromium (Cr) coated. Since Cr-coated cryosamples on carbon-grid supports have very low mass density and because signal to noise is low in HRSEM recordings, especially in regions which overhang holey carbon expanses, then the combined contrasts obtained in a composite image containing STEM and HRSEM contrasts result in greater detail recognition.

Tandem cryo-imaging, using an in-lens field emission (FE) SEM (DS-130F) operated at 25kV and fitted with above-lens secondary electron detector and below-lens scanning transmission detector, provided digital images of frozen cells and macromolecular complexes.
Ultrastructural Analyses of Living Animal Organs Prepared by “in vivo Cryotechnique” for Electron Microscopy
Authors: Ohno S , Takayama I , Terada N , Fujii Y , Ueda H , Baba T
Published: July 2020

It is well known that hemodynamic factors, such as blood pressure and flow, exert an important influence on native morphology of various animal organs. However, information about the significance of ultrastructures which are revealed by conventional preparation methods has been limited, because routine chemical fixation of cells and tissues takes considerable time, during which their morphology could easily change. Therefore, morphological studies with routine immersion or perfusion fixation have not revealed real ultrastructures of functioning animal organs with normal blood circulation.2 The ultimate goal of morphological study is that all features to be examined should reflect the physiological meaning under investigation. For that purpose, the preservation of cells and tissues in functioning organs is necessary for studies to define their ultrastructures. Most cryotechniques have been based on the use of prior excised tissues. Such small specimens are commonly frozen within several seconds following the excision of the tissues.
New Environmental Scanning Electron Microscopic (ESEM) Observations of Bacteria on Simulated Soil Substrates
Authors: Holden P , Pierce D
Published: July 2020

Conventional scanning and transmission electron microscopy (SEM and TEM) of the rhizosphere (soil around plant roots) has been used to describe the spatial organization of biotic (microorganisms including bacteria and fungi) and abiotic (organomineral complexes and clay platelets) constituents in soil.1 However, soil is deeper than plant rootS2 and the spatial distribution of microbes, the morphology of the microbial growth habit, and the spatial association of microbes with mineral substrates in the deeper vadose zone are little known. That subsurface terrestrial microbes catalyze most major nutrient-cycling reactions in the terrestrial biosphere3 punctuates the need to observe the true morphology of bacteria in association with mineral surfaces and microbemicrobe associations. Here, we present our use of environmental scanning electron microscopy (ESEM) to image bacteria on unsaturated sand, a simple surrogate for heterogeneous soil. ESEM is a choice tool for high resolution imaging of combined soft and hard matter, where delicate hydrated expolymer matrices bind microbes to each other and to soil particles as biofilm.4
3d Image Reconstruction of Frog Virus 3 At 2.6nm
Authors: Yan X , Bowman V , Murti G , Goorha R , Hyatt A , Baker T S
Published: July 2020

Frog virus 3 (FV3), a member of the genus Ranavirus (family Iridoviridae), was isolated from the leopard frog Rana pipiens. Members of this genus are recognized pathogens of amphibians, reptiles and fish and have been associated with declines of amphibians in the United Kingdom and the USA. Neutron-scattering studies showed that FV3 virions are composed of four concentric layers: an outer lipid envelope containing protein VP58; an icosahedral capsid shell with major capsid protein VP48; an inner lipid membrane with VP63 and 44; and a central core of dsDNA (∼170 kbps) and associated proteins. The FV3 genome has a terminally-redundant and circularly-permuted sequence. Naked virions (i.e. without the envelope lipid) contain more than 20 different proteins and about 9% lipid, which is required for infectivity. to date, structural information about FV3 has primarily been obtained in electron microscopy studies by means of thin-sectioning and negative staining techniques.
Effects of Electron-ion Recombination on Contrast in ESEM Images
Authors: Toth M , Thiel B L , Donald A M
Published: July 2020

We present experimental evidence for the effects of electron-ion recombination on contrast formation in secondary electron (SE) images obtained using an environmental scanning electron microscope (ESEM). Inclusion of the effects of SE-ion recombination in the theory of ESEM image formation accounts for contrast reversal observed, under appropriate conditions, in SE images of conductors (ie, in the absence of localized specimen charging) and of insulators that exhibit localized charging. Previously unexplained dynamic contrast caused by temporal charging can be understood if both conventional models of the effects of charging on SE emission, and the proposed role of SEion recombination in ESEM image formation are accounted for.

In an ESEM, the extent of charging exhibited by insulating specimens can be controlled by varying the type and pressure (P) of the imaging gas, and operating parameters that determine the extent to which the gas is ionized (eg, detector bias, VGSED, and working distance, WD).
Tele-Tutoring - from Learning to Earning; Part III: the Fun Begins
Authors: Lang J , Staun C , Casuccio G , Kennedy S , Kritikos D , Schlaegle S , Lentz H
Published: July 2020

The West Greene School District (WGSD) in partnership with RJ Lee Group (RJLG) is developing innovative programs as part of the Schoolhouse Project to provide exceptional educational and business opportunities to its students. The objectives of the educational/business partnership 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. Access to remote analytical instrumentation is a key component of the Schoolhouse Project. to this end, RJLG has developed Web-based technologies (WEBSEM™) which enable control and operation of a scanning electron microscope (Personal SEM® or PSEM) over the Internet. A key component of the project will be the establishment of an incubator laboratory extension of RJLG at the WGSD. This laboratory will function as a learning laboratory during the school day and as a business during the evenings and weekends.
Image Processing Methodology for Determining SI Precipitate Size and Density in Oxide Layers from Conical Dark Field TEM Micrographs
Authors: Domenicucci A
Published: July 2020

Image processing techniques have been used for decades in many branches of science. with the advent of low cost, highresolution CCD cameras and the advances in personal computing, techniques previously used in other disciplines are increasingly being applied by transmission electron microscopists. The present paper gives an example of using image processing techniques for characterizing the number and size of second phase precipitates in an oxide matrix.

Si inclusions in the form of Si precipitates can occur in silicon dioxide films. The inclusions are contained within the films and effectively reduce the local thickness of the oxide. This thinning results in a reduction in the voltage necessary to cause oxide breakdown; the larger is the precipitate, the lower the breakdown voltage. Knowledge of the precipitate size and density is therefore important when assessing the dielectric integrity of these films. The Si precipitates are crystalline and more or less randomly oriented within the matrix.
Quantitative Microscopy for Analysis of Hydrogel Pore Structure
Authors: Marshall Andrew J , Ratner Buddy D
Published: July 2020

Introduction Applications for porous biomaterials include scaffolds for tissue engineering and spatial control of wound healing. Porous hydrogels are of particular interest due to their hydrophilic nature, elasticity, and mechanical compatibility with soft tissues. We present an optical technique for quantitatively analyzing the pore structure of porous hydrogel materials. The technique presented here is especially useful for analyzing a new class of porous hydrogels with spherical pore shape. Many important properties of the three-dimensional pore structure of these materials can be quantitatively described by analyzing a twodimensional slice (thin section) of material.

Materials and Methods

Porous cross-linked hydrogels were prepared using a previously described method. Briefly, poly(hydroxyethyl methacrylate) (polyHEMA) was polymerized around a pore template of close-packed poly(methyl methacrylate) (PMMA) microspheres (Sekisui Plastics, grade MB-8C or MB-20C). The microspheres were then leached out with 90% v/v acetone.

Scanning electron microscope (SEM) images were obtained using an FEI 2020 Environmental SEM with a gun voltage of 15 kV and a chamber pressure of 5 torr.
Color Management System
Authors: Male Philippe
Published: July 2020

Perception of color. in 1917, Alfred Munsell created a “notation of colors” based on the human perception of colors (Fig 1). The “tri stimuli” sensitivity of red, green and blue of the eye cones allows humans to live in an additive color space. Munsell showed that any color is defined by three components: 1-Hue, similar to different visible wavelengths. 2-Chromaticity or saturation, similar to concentration of dyes. 3-Value or brightness, representing black and white.

Color Space and Gamut. Three conditions must be met to know the existence of an object, they are 1- An Illuminant (5000°K for photography), 2- An Object (Reflective, Transmissive or Emitting), 3- An Observer (Viewer, monitor, camera, detector). in 1931 La Compagnie Internationale de l’Eclairage, or CIE, met to develop a standard. This resulted in the CIE Color Space defined as a 3D volume of gamut of colors (Fig 2). Different vector notations can be used to define colors: Hue Saturation Lightness or Value (HSL or HSV), RGB (Red Green Blue), Lab (Lightness and two coordinates), and CMYK (Cyan Magenta Yellow Black).
From Digital Imaging to the Publisher: Navigating the Digital Journey
Authors: Sedgewick J
Published: July 2020

With the increased frequency of digital presentation of research on laptops at meetings, on the web and to journals, the need arises for a unified set of computer programs. The best of all worlds would be to create text, graphs, images and HTML in one program only, but the reality is that several need to be used without much duplication of effort. The ideal situation is one in which the computer applications are open-ended, so that one application saves in a format that is readable by another application across Macintosh® and PC platforms. At the same time, the applications should be straightforward to use.

Taking only the above conditions into account, even the most cursory examination would reveal that Microsoft® products are, in fact, closed systems at best and dead end at worst. PowerPoint® is a good example of a program that can only do one thing—make slides or on--screen presentations--but dead ends because high resolution image files cannot be saved from the program, nor can files export to HTML or to a file usable by a publisher.
Telemicroscopy in Pathology Diagnosis
Authors: Howell D N , LeFurgey A , Tuszynski A , Shelburne J D
Published: July 2020

Telepathology, derived from the Greek words tele, or “far off,” and pathologia, literally, “study of the emotions,” is a branch of telemedicine in which information about tissue or body fluid samples obtained at one location is transmitted to a distant site for analysis. in its broadest sense, telepathology can be thought of as encompassing any form of remote information transfer about specimens harboring potential disease processes, including verbal communication via telephone. in a majority of cases, however, the term is used to describe interactions involving transmission of microscopic images, or telemicroscopy. Such transmission can occur through a wide variety of media; sharing of printed images is one venerable mechanism that persists in robust form to this day, facilitated and expedited by efficient express-mail systems. Increasingly, however, the terms telepathology and telemicroscopy have acquired the connotation of rapid electronic transmission of digitized images. Facsimile transmission of micrographs is a rudimentary version of this process, but most modern systems employ some form of digital camera attached to a microscope.
Solvent Isotope Effects in Atomic Force Spectroscopy
Authors: Forbes Jeffrey G , Santos John P
Published: July 2020

The utility of the atomic force microscope (AFM) for measuring forces is now well established. The AFM is capable of measuring forces from tens of piconewtons to tens of nanonewtons. Systems ranging from the adhesion of clean or functionalized tips interacting with different surface, to singlemolecule measurements of the force required to rupture protein-ligand interactions, to the forced unfolding of single protein molecules have been studied. The adhesion of a clean silicon nitride tip to a clean glass surface is one of the simplest systems to study and was the first system to demonstrate quantized adhesion. AFM cantilevers will adhere to glass surfaces in the presence of water and the force required to separate the surfaces is on the order of 1-6 nN at low pH. The adhesion mechanism is believed to be due to hydrogen bonds formed between the silanol groups present on both the glass and AFM tip. Deuterium oxide (D2O) has physical properties significantly different from that of H2O; the density, melting temperature and heat capacity are all greater than that of water. These and the differences between H2O and D2O can be attributed to the lower vibrational frequency of the OD bond and the fact that O-D…O bonds are about lkJ/mol stronger than O-H…O bonds.
Quantifying Molecular Forces: Sensitivities and Spring Constants Without Touching a Surface
Authors: Proksch Roger , Cleveland Jason
Published: July 2020

Recent work has demonstrated the ability to measure forces between and within single molecules using cantilever-based instruments. Force measurements on molecules can provide structural and dynamic information not available with other techniques. Figure 1 shows an example force-distance curve made of lambda digest DNA being stretched by a cantilever, showing the characteristic plateau at 65 pN as the DNA goes through the B-S transition. Implicit in these measurements is a need for carefully quantifying the forces the cantilever is exerting on the single molecule. This requires a low noise system that provides accurate measurements of the cantilever spring constant, cantilever bending, and the relative cantilever-sample separation. We have developed an instrument with several improvements that allows these measurements to be made quantitatively. One component is an improved optical lever that provides an extremely sensitive measurement of the cantilever deflection. A separate sensor measures the position of the moving base of the cantilever and allows thermal drift, piezo scanner hysteresis, and creep effects to be corrected.

In force measurements with micro-machined cantilevers the application of Hooke's law (F = −kx) requires two quantities: x, the distance the flexing cantilever moves and the “spring constant” k. The optical lever is the most commonly used method for measuring the deflection of a cantilever.
A New High Resolution Field Emission SEM with Variable Pressure Capabilities
Authors: Gnauck Peter , Drexel Volker , Greiser J
Published: July 2020

To examine non conductive samples in their natural state (i.e. without significant sample preparation) at high resolution in the SEM the technique of low voltage field emission scanning electron microscopy (LVFESEM) is used. Due to the limitation in accelerating voltage (U<1kV) this technique is limited in respect of chemical analysis. Furthermore it is not possible to examine humid and outgassing samples in high vacuum. in recent years the application of variable pressure scanning electron microscopes (VPSEM) became an important technique in materials science as well as in life science. Due to the capability of maintaining a high chamber pressure humid, outgassing and non-conductive samples, can be examined in their natural state without significant sample modification or preparation. Especially compound materials with different electron yields can be imaged without any charging effects (Fig. 2), [2]. This paper describes a high resolution field emission electron microscope, that combines low voltage and variable pressure capabilities.

The high pressure capabilities of the instrument are realized by eliminating the high vacuum requirements of SEM in the microscope chamber. This is done by separating the vacuum environment in the chamber from the ultra high vacuum environment in the gun area.
NanoSIMS 50: Recent Results and Intrumental Development in Submicron Isotopic and Elemental Analysis
Authors: Horreard Francois , Hillion Francois , Cecile Fournier Dr
Published: July 2020

Secondary Ion Mass Spectrometry (SIMS) has unique features that makes this technique a very attractive candidate for sub-micron analysis: high elemental sensitivity (ppm or better) if reactive primary ions are used ; isotopic analysis capability ; possible insulator analysis ; no sample preparation needed ; small probed depth (a few run) and small interaction volume (cascade collision dia. < 10 nm).

Similar to a SEM microscope, a beam of Cs+ or O− primary ions is focused and rastered on the surface of the sample. The ions sputtered by this primary beam are collected, and this secondary ion beam is shaped in order to be mass filtered by a magnetic sector mass analyzer. Five mass selected images can be simultaneously recorded, originating from the exact same sputtered volume, ensuring reliable isotopic ratio and perfect image registration.

Based on Pr. Slodzian and al. [1, 2] original design, the commercial version of the NANOSIMS 50 ion microprobe incorporates several new developments in order to improve performances:
High-Resolution Imaging with an Aberration-Corrected Transmission Electron Micrscope
Authors: Lentzen M , Jahnen B , Jia CL , Urban K
Published: July 2020

In electron microscopy high-resolution imaging of finest object structures is generally hampered by the influence of aberrations of the lens system, especially the high spherical aberration of the objective lens. The delocalization of contrast details induced by aberrations is especially strong for microscopes equipped with a field emission gun providing a high spatial coherence. in recent years a prototype of an aberration correction system has been constructed by Haider et al., following a suggestion by Rose, consisting of two hexapole elements and four additional round lenses. The correction system was adapted to a Philips CM 200 FEG ST microscope with an information limit of 0.13 nm. The alignment is carried out using aberration measurements deduced from Zemlin tableaus. By appropriately exciting the hexapole elements it is possible to reduce or even fully compensate the spherical aberration of the objective lens.

With the freedom of a variable spherical aberration Cs new operation modes can be accessed that are not available in standard microscopes. with Cs = 0 and defocus Z = 0 pure amplitude contrast occurs, together with a vanishing contrast delocalization; phase contrast with a single, narrow pass-band up to the information limit can still be achieved by Z = ±7 nm, which introduces a delocalization of R = 0.13 nm. with Cs = 97 μm and Z = −18 nm the broad Scherzer pass-band for phase contrast can be extended to the information limit, with R = 0.35 nm. For the CM 200 Cs = 43 fim and Z = −12 nm still produces a high level of phase contrast, comparable with the extended Scherzer pass-band, but with R = 0.08 nm only. in the latter mode Scherzer’s defocus equals Lichte's defocus of least confusion.