bluuebunny/crossref_metadata_2025_split huggingface dataset:
Three Dimensional Optical Data Storage Using Two-Photon Induced Photobleaching in a Polymer Matrix
Authors: Bailey GW , Dimlich RVW , Alexander KB , McCarthy JJ , Pretlow TP , Pan S J , Shih A , Park M S , Liou W S , Bhawalkar J , Prasard P , Cheng P C 
Published: July 2020

Abstract
The intensity of two-photon induced fluorescent shows quadratic dependency to the excitation intensity, as a result, one can achieve optical sectioning in fluorescent microscopy without the use of a confocal aperture. When the excitation power is properly adjusted, the fluorescent and photobleached volume is restricted to the vicinity of the focal points; therefore, it is possible to use this mechanism to achieve 3D data storage and microstructure fabrication (stereolithography).
The recording medium used in this experiment was poly-HEMA block doped with a high efficient two-photon fluorophore, APSS, (4-[N-(2-hydroxyethyl)-N-methyl) amino phenyl]-4’-(6-hydroxyhexyl sulfonyl) stilbene). The block was made by dissolving APSS in HEMA with an initiator, 2,2’-azobisisobutyronitril (AiBN) (1% mole ratio) and polymerized at 60° C for 48 hours. The polymer was then trimmed into a small rectangular block (3×5×1 mm3) and surfaced by using a ultramicrotome with a glass knife. A modified Biorad MC500 LSM equipped with a home-made computer controlled stage scanner was used for both writing (stage scanning) and read-back (beam scanning).
Using Multiphoton Microscopy for the Study of Embryogenesis
Authors: White John , Centonze Victoria , Wokosin David , Mohler William 
Published: July 2020

Abstract
Multiphoton fluorescence excitation imaging is an optical sectioning technique for fluorescence microscopy. At very high photon densities, two or more photons may coordinately excite an energy transition in a fluorophore that corresponds to the sum of the energies of the individual photons. by this means, a fluorophore may be excited by a wavelength that is considerably longer than its single photon excitation wavelength. Ultra-fast pulsed (femtosecond) lasers can produce the peak power densities in the focal volume of an objective lens needed to provide sufficient 2- or 3- photon excitation events for imaging. The use of short-pulse lasers provides the high peak powers necessary for imaging yet with modest mean power levels that do not thermally damage biological specimens. Production of multiphoton events depends on the square of photon density for 2-photon excitation and the cube of photon density for 3-photon excitation. The power density therefore rapidly falls off away from the focal volume of an objective lens, thereby confining fluorescence excitation to the focal volume.
Coronary Intravascular Ultrasound
Authors: E. Nissen Steven , Murat Tuzcu E 
Published: July 2020

Abstract
For several decades, contrast angiography has served as the principal imaging modality used to assess the anatomic severity of coronary artery disease. Recent technical advances in acoustics and microelectonics have permitted development and refinement of miniaturized ultrasound devices capable of real-time tomographic coronary imaging. This approach, intravascular ultrasound, represents an emerging alternative to angiography for direct visualization of coronary anatomy during diagnostic and interventional catheterization. Clinical studies comparing angiography to intravascular ultrasound have demonstrated frequent differences in quantitative or qualitative findings. Accordingly, intraluminal ultrasound imaging is increasingly utilized to confirm, refute, or supplement angiographie data in patients with coronary disease.
The discrepancies between angiography and intravascular ultrasound can be explained by the characteristics of these two different imaging techniques. Angiography, which portrays the vessel as a silhouette of the lumen, whereas ultrasound depicts the coronary from a tomographic perspective, providing cross-sectional images that portray not only the lumen, but also the deeper intramural structures.
Rapid, Automated, and Robust Tracing of Vasculature, and Quantification of Visual Features from Angiographic Images
Authors: Can Ali , Shen Hong , Al-Kofahi Khalid , Turner James N , Tanenbaum Howard L , McCandless Brian , Roysam Badrinath 
Published: July 2020

Abstract
The rapid tracing of vasculature, and quantification of visual landmarks such as those corresponding to the branching and crossover points from images is extremely useful in a variety of fields including ophthalmology, radiology, and neurobiology. A novel algorithm that enables rapid, automatic, robust, adaptive, and accurate tracing of vasculature has been developed. Given an image (Fig 1), it automatically generates a labeled graph representation of the vasculature (Fig 2), and a table listing the locations of visual landmarks such as crossover and branching points (Fig 3). For each such point, it also lists the intersection angles, and the local thickness of the intersecting vasculature segments. This data is often useful by itself. They can also be used for image registration and montage building.
This algorithm greatly improves upon previous work in several ways. First, it is fully automatic, and free of parameters that need to be adjusted carefully (just needs optional sensitivity setting).
Three Dimensional Molecular Scale Imaging of Plasma Proteins Under Aqueous Conditions
Authors: Marchant Roger E , Holland Nolan B , Siedlecki Christopher A 
Published: July 2020

Abstract
Atomic force microscopy (AFM) provides unique opportunities to study cell-surface and molecular scale interactions in three dimensions under aqueous conditions. In AFM, a small probe attached to cantilever (fig. 1) is used for interacting with a sample to obtain sensitive measurements of molecular structure, intermolecular forces (sub-nN) and interfacial properties. The data ouput can be presented in the form of a topographical image, force map or viscoelastic response (e.g., Figs. 2-4). Thus, AFM combines high resolution imaging with the ability to measure surface-dependent intermolecular forces and properties. AFM also is amenable for coupling with optical imaging methods including immunofluoresence and gold bead labeling.
This presentation will focus primarily on the use of AFM for molecular level imaging of plasma proteins, von Willebrand Factor (vWF) and fibrinogen. Both proteins play central roles in the regulation of hemostasis and thrombosis by participating in coagulation or by facilitating adhesion, spreading and aggregation of activated platelets.
Cryoelectron Microscopy of Red Cell Skeletons Reveals that Spectrin has a Helical Conformation
Authors: Yang Li , Josephs Robert 
Published: July 2020

Abstract
In vivo the red blood cell reversibly and rapidly deforms as it passes through the small capillaries. Although the physiochemical basis of the red cell's deformability is unknown, it is regarded as being a property of the membrane protein spectrin. We have used cryoelectron microscopy to study the structure of spectrin in membrane skeletons to determine how its molecular structure confers elastic properties on the cell membrane. Cryomicroscopy has the virtue of minimally perturbing easily deformable structures such as spectrin.
Figure 1 is an electron micrograph of a portion of a frozen-hydrated red cell skeleton. The spectrin molecules are indicated by the arrow heads. They cross link the skeletal network by interacting with short rod like segments F-actin (indicated by the arrows) containing about 13 actin molecules. In such micrographs the spectrin appears to have a sinusoidal shape whereas in negatively stained preparations spectrin appears to be straight.
We have used the procedure of Margalef in order to determine the three dimensional trajectory of the spectrin molecule.
Practical Methods for TEM, Part II.
Authors: Chien K , Gonzalez R , Heusser RC , Shiroishi H , Heathershaw ML 
Published: July 2020

Abstract
This is an extension of our presentation from last year. We intend to continue the discussion and review several practical procedures developed in our laboratory for routine and immuno-electron microscopy.
TEM Vs IM-LM In the last decade, the use of diagnostic TEM in the medical field has experienced a drastic decline. The main reason is due to the advances of immuno-labeling techniques for light microscopy and also the decreased coverage of medical insurance for EM. Currently, immuno-histochemistry or in situ hybridization staining can be performed on large paraffin or frozen sections. These procedures can be performed quickly and much less expensively than TEM. However, TEM is still needed when PAP staining is not specific or minimum numbers of cells are stained. It is also possible to process immuno-labeled paraffin slides for TEM examination to confirm a diagnosis. In addition, when only a few microorganisms such as pneumocystic carinii or protothecosis are stained by Grocott’s methenamine silver in paraffin sections, a re-examination and confirmation by TEM can be performed without the use of uranium or lead staining.
The Development and Application of the Tripod Polishing Technique
Authors: Benedict J , Klepeis SJ , Anderson R 
Published: July 2020

Abstract
The Tripod polishing technique is used to mechanically polish materials for further analysis by optical, SEM or TEM. The mechanical polishing is done using the Tripod Polisher (FIG. 1), which consists of three Delrin capped micrometers and an L-bracket. The micrometers provide accurate side-to-side and front-to-back adjustments of the polishing plane. The L-bracket is where the sample is attached to the polisher and it comes in a number of configurations, depending on the type of analysis needed. by attaching the sample at different locations on the L-bracket, either planar sections or cross sections can be made using the Tripod Polisher.
A sample to be cross sectioned is attached to the front of the L-bracket with wax. The micrometers are then adjusted so the bottom of the Delrin feet are aligned with the area of interest. The polisher is held on a rotating diamond wheel, with the Delrin feet and the sample in contact with the wheel.
Negative Staining: a Valuable Technique for Studying Subcellular Components
Authors: Miller Sara E 
Published: July 2020

Abstract
Negative staining is the most frequently used procedure for preparing particulate specimens, e.g., cell organelles, macromolecules, and viruses, for electron microscopy (Figs. 1-4). The main advantage is that it is rapid, requiring only minutes of preparation time. Another is that it avoids some of the harsh chemicals, e.g., organic solvents, used in thin sectioning. Also, it does not require advanced technical skill. It is widely used in virology, both in classification of viruses as well as diagnosis of viral diseases. Notwithstanding the necessity for fairly high particle counts, virus identification by negative staining is advantageous in not requiring specific reagents such as antibodies, nucleic acid probes, or protein standards which necessitate prior knowledge of potential pathogens for selection of the proper reagent. Furthermore, it does not require viable virions as does growth in tissue culture. Another procedure that uses negative contrasting is ultrathin cryosectioning (Fig. 5).
In 1954 Farrant was the first to publish negatively stained material, ferritin particles.
A New Preparation Technique for High Resolution Imaging of Protein Structure: Casein Micelles.
Authors: McManus William R , McMahon Donald J 
Published: July 2020

Abstract
Models for the structure of the bovine casein micelle have been proposed in the past (1,2,3,4). These models are based on the chemical and physical properties of the micelles and fall into two general catagories, framework and submicelle models. Electron Microscopy techniques were one of the tools used in the development of these models. However, no definative model has been established. We have developed a new electron microscopy method and it is being applied to the re-examination of the protein structure of the casein micelle, with the goal of establishing a definative model for the structure of the casein micelle.
High resolution scannning electron microscopy has proven unsuccessful in revealing the protein structure in the casein micelle (Fig 1). To create high resolution scanning electron microscopic images, fine metal coatings are required in the 5 to l0nm range. Following the application of these coatings, images of casein micelles resemble a melting lumpy sphere. This is due to the metal layer obscuring the proteins from view.
A Novel use of Fluorescence Microscopy in Evaluation of Renal Biopsies
Authors: McMahon JT , Myles JL , Tubbs RR 
Published: July 2020

Abstract
Light, immuno, and electron microscopy are standard for evaluation of renal biopsies. For light microscopy (LM), special stains including PAS and Jones silver methenamine (JSM) are frequently used to enhance recognition of renal anomalies related to disease. We recently discovered that fluorescence microscopy (FM) extends the usefulness of frozen and paraffin sections stained with hematoxylin and eosin and may presage the findings of immuno and electron microscopy. With UV illumination and reflected light fluorescence excitation, standard histologie sections reveal pathologic glomerular and other renal changes not evident by conventional bright field microscopy and may obviate the need for additional special stains.
For frozen sections, tissues mounted on gum tragacanth were snap frozen in isopentane chilled with liquid nitrogen and cryosectioned at a thickness of 4-6 μm. For paraffin sections, tissues were fixed in neutral buffered 10% formalin or in Hollande’s fixative (3.6% formalin, 40% picric acid, 25% copper acetate, 1.5% acetic acid) and sectioned at 2-4 μm.
A New ion Beam Based Etching/Coating System for Scanning Electron Microscopy (SEM) and Light Microscopy (LM)
Authors: Alani R , Mitro RJ , Tabatt CM , Malaszewski L 
Published: July 2020

Abstract
The design and performance of a new instrument, based on improved Penning ion guns [1] for etching and coating samples for SEM and LM in a single vacuum chamber, are described. The instrument is based on an existing high resolution ion beam coating system, which is capable of producing high quality ultra-thin and amorphous conductive films, required for present high resolution electron microscopes. [2]. The fact that in this system both etching and coating processes are combined in one chamber, the specimen handling and specimen contamination are minimized. Furthermore, the system eliminates the traditional multiple mounting /dismounting of samples to various holders for mechanical polishing, etching, coating and microscopy purposes. The specimen can stay with the same holder throughout the entire process, increasing the sample through-put. Moreover, the system offers an alternative method to the traditional “wet chemical etching,” technique with its well known problems.
Video Light Microscopy
Authors: Spring K R , Herman B , Salmon E D 
Published: July 2020

Abstract
This tutorial emphasizes the fundamentals of the use of light microscopy in combination with electronic imaging. The goal of the tutorial is to enable the attendees to make informed choices both about the modes of imaging best suited to their application and about the most suitable components to be employed. The didactic portion of the program will consist of five presentations, each dealing with different aspects of modern imaging systems and their applications to problems of biological significance. A laboratory demonstration session, organized to complement the lectures will follow.
The morning session will begin will a brief review by Dr. Spring of the principles of light detection and the formation of the video signal. Dr. Salmon will then describe video-enhanced contrast microscopy. This transmitted light imaging technique, widely utilized to visualize low contrast specimens exploits the wide dynamic range and high gain of video cameras for the capture of images that are virtually invisible through the eyepieces because of high background light.
Environmental Scanning Electron Microscopy: - Advantages and Disadvantages
Authors: McKernan Stuart 
Published: July 2020

Abstract
The possibility of performing scanning electron microscopy under “environmental” conditions (ESEM); where the specimen does not have to be under high-vacuum conditions, or even coated to make it conductive, has existed for several years[l]. Several different flavors of environmental scanning electron microscope now exist, as well as a newer generation of microscope which is capable of imaging at very low accelerating voltages. Techniques for rapidly freezing hydrated specimens and obtaining very high resolution images from them in the SEM have also been improved recently. As a result of all this innovation, it is now possible to examine many classes of specimens in the SEM that were previously thought to be impossible to image (or at least not worthwhile frying).
Among the advantages of the environmental SEM are the fact that images of non-conductive surfaces can be obtained without the necessity for additional sample coating. This can be especially important in dynamic experiments, and hot-stage work, where the presence of a surface coating may substantially affect the samples behavior
Biological Applications of Environmental Scanning Electron Microscopy
Authors: Gilpin C J 
Published: July 2020

Abstract
The environmental scanning electron microscope (ESEM) first marketed by ElectroScan and now by FEI/Philips has been recognized as the only scanning electron microscope which allows liquid water to be present in the sample chamber at temperatures above freezing. As most biological material contains a high percentage of water it would seem essential to use this technology to examine specimens in their natural state. The purpose of this presentation is to describe in detail the way in which the microscope should be used to maximize the information obtainable from a variety of biological samples. This tutorial will also consider methods which can be applied to “difficult” samples whose structure becomes altered during what would be considered a normal imaging schedule.
The main features of the microscope are the use of the Peltier effect cooling stage and control of chamber water vapor pressure to enable wet specimens to be imaged.
Novel and Advanced Applications of the Low Vacuum and Environmental Scanning Electron Microscope (SEM)
Authors: Griffin Brendan J 
Published: July 2020

Abstract
The environmental SEM is an extremely adaptive instrument, allowing a range of materials to be examined under a wide variety of conditions. The limitations of the instrument lie mainly with the restrictions imposed by the need to maintain a moderate vacuum around the electron gun. The primary effect of this has been, in a practical sense, the limited low magnification available. Recently this has been overcome by modifications to the final pressure limiting aperture and secondary electron detector (Fig.l). The modifications are simple and users should be brave in this regard.
A variety of electron detectors now exist including various secondary, backscattered and cathodoluminescence systems (Figs 2-5). These provide an excellent range of options; the ESEM must be regarded as a conventional SEM in that a range of imaging options should be installed. In some cases, e.g. cathodoluminescence, the lack of coating provides an advantage unique to the low vacuum SEMs.
Field Emission TEM and STEM of Ultrafine Metal Particles
Authors: Disko M M , Orchowski A 
Published: July 2020

Abstract
Accurate descriptions of dispersed metals are of central importance in optimizing the activity, selec-tivity and stability of a diverse set of catalysts and chemistries. Improved methods for quantifying metal dispersion, alloying and support interactions help form mechanistic understandings of catalyst function at the atomic scale. In this paper we discuss ideal capabilities of a transmission electron microscope for catalysis, and give an update on the use of a next-generation field-emission TEM/STEM for structural and analytical studies of supported metal catalysts.
Characterizing nanometer-sized metal particles requires high performance imaging, high sensitivity analysis, and minimal disruption of the physical state of the particles. No single microscope combines all key performance factors with ease of use. Schottky field-emitter instruments provide high current-density probes with excellent stage stability (nm drifts in &gt; 10 min. observed), &lt; 0.7 eV energy reso-lution for EELS, and a turbo-pumped vacuum system for minimal carbon contamination while using nanometer probes and nanoamps of current. Scanning TEM performance is also key.
Mesoscopic Silica Thin Films Via Template-Assisted Self-Assembly
Authors: Yao N , Trau M , Manne S , Nakagawa N , Lee T , Honma I , Aksay I A 
Published: July 2020

Abstract
Synthesis of mesoscopic silicates has stimulated considerable interest as a biomimetic approach to the fabrication of organic/inorganic nanocomposites. However, for future applications of these materials, controlled shapes and patterns, particularly as continuous thin films, rather than the microscopic particulates, need to be processed. Recently, we have described a synthesis scheme, using the supramolecular assemblies of surfactant molecules as a template for the condensation of inorganic species, to prepare silica mesoscopic thin films at a solid interface from a bulk solution. Here, we concentrate on the growth of such thin films and the effect of the template on the nanostructure formation.
We employed tetraethoxy silane (TEOS), dissolved in acidic solution, as a silicate source and cetyltrimethyl ammonium chloride (CTAC) as the templating surfactant. Typical molar ratio was 1 TEOS : 1.2 CTAC : 9.2 HC1 : 1000 H2O. Concentrations of TEOS and HCl in the mixture were approximately l/7th of those for typical particle synthesis scheme, in order to sufficiently slow down the rate of TEOS hydration such that homogeneous nucleation is effectively switched off.
Microstructural Instability in Mosi2/Sic Nanolayers
Authors: Lu YC , Kung H , Hirvonen J-P , Jervis TR , Nastasi M , Ruck D , Mitchell T E 
Published: July 2020

Abstract
Thin film multilayers have been the focus of extensive studies recently due to the interesting properties they exhibit. Since the improvement in properties can be attributed directly to the unique nanoscale microstructures, it is essential to understand the factors affecting the microstructural stability in these nanolayer structures. The intermetallic compound, MoSi2, despite its superior oxidation resistance and high melting point, suffers from inadequate high temperature strength and low temperature ductility, properties which hinder its high temperature structural applications [1]. SiC is a potential second phase reinforcement due to its high temperature strength and thermal compatibility with MoSi2. The addition of SiC in a nanolayered configuration has been shown to exhibit significant increase in hardness after annealing [2]. It has also been shown that when annealed above 900°C, the layers break down and grain growth sets in, with a significant decrease in hardness and. Due to the lack of a thermochemical driving force, the two phases remain separate at all temperatures investigated. In this study, the stability of the MoSi2/SiC nanolayers structure under ion irradiation has been investigated.