bluuebunny/crossref_metadata_2025_split huggingface dataset:
Morphological Characterization of an Elastin-Mimetic Triblock Copolymer Utilizing CRYO-HRSEM
Authors: Wright ER , Conticello VP , Apkarian RP 
Published: July 2020

Abstract
The elastin-mimetic tri-block copolymer, C5, with the polypeptide repeat [((VPAVG)(IPAVG)3(VPAVG))m((VPGVG)2(VPGEG)(VPGVG)3)n((VPAVG)(IPAVG)3(VPAVG))m] was produced via protein hyper-expression utilizing a pET plasmid and Escherichia coli (BL21- Gold(DE3)) as the bacterial host. The gene coding for the polypeptide was produced by a multimerization protocol that has undergone recent modifications. A sample of the elastinmimetic block copolymer, C5, was prepared as a 20 to 25 percent protein solutions in sterile ddH20. Approximately 10 μL of the solution was pipetted into 3 mm gold planchets (Balzers BU 012 130T), which had been pre-equilibrated to 4°C in an isothermal environmental cooler (Torrey Pines Scientific). The temperature of the cooler was raised to 20°C and allowed to stabilize for 10 minutes. The solidified samples, were plunge-frozen in liquid ethane at its melting point (−183°C); the samples were stored in liquid nitrogen (LN2). A sample was transferred to and mounted on the precooled (∽−170°C) Oxford CT-3500 cryo-stage held in the cryo-preparation chamber.
Artificial Myocardium: Design Principles and Substratum
Authors: Yost Michael , Price Robert , Simpson David , Terracio Louis 
Published: July 2020

Abstract
Death and disability due to cardiovascular disease and congenital anomalies remains a significant health problem in the United States. Despite improvements in detection, patient management, surgery and preventative medicine, the quality of life for people who suffer from cardiovascular dysfunction has a major impact on our society. The intact heart is an elaborate three-dimensional structure that insures the orderly propagation of electrical signals coordinating the contraction and relaxation of the ventricular wall. Localized loss of muscular tissue as a result of congenital defect or disease process alters this structural arrangement and impairs overall cardiac function. Conventional surgical techniques cannot begin to adequately restore the subtle structural and functional relationships in the heart. The ability to construct a tissue-engineered prosthesis composed of cardiac muscle cells in a collagen-based scaffold may potentially offer a superior alternative to currently available surgical techniques.
A tissue engineered myocardium must have the following components: First, it must develop and maintain the correct cellular phenotype as well as a functioning contractile apparatus of parallel myofibrils, Second it must be able to form gap junctions within itself and with the native tissue and these gap junctions must be competent at conducting electrical pacing as well as other biochemical signals, and Third, it must be capable of participating in and contributing to the rhythmic contraction of normal myocardium as well as accommodate the changes in contraction frequency ubiquitous in the cardiac environment
Electrospinning Applications in Bioengineering: Fabrication of Bio-Engineered Skeletal Muscle
Authors: Telemeco T , Bowlin GL , Matthews JA , Cohen NM , Vida M , Wnek GE , Terracio L , Simpson DG 
Published: July 2020

Abstract
The objective of this study is to develop a skeletal muscle prosthetic composed entirely of natural or otherwise bioresorbable materials that recapitulates the structure and function of intact muscle. in our fabrication strategy we begin by electrospinning (see Mathews et al., this volume) a hollow, cylindrical fascial sheath composed of poly-glycolic acid (PGA), poly-lactic acid (PLA), Type I collagen microfibers or a blend of these materials (figure 1). The resulting fascial sheath is a highly porous fabric composed of interwoven fibers that range from less than 1 micron to 2-5 microns in diameter (patents pending). Next, we isolate neonatal rat skeletal myoblasts by enzymatic dissociation. The dissociated tissue is subjected to an interval of differential adhesion to enrich the preparation in skeletal muscle myoblasts. The final cell pellet of myoblasts is then suspended at high density in Type I collagen. This suspension is polymerized at 37°C for 10-15 minutes and used to fill a fascial sheaths (patents pending).
Microspectroscopy Using a Solid Immersion Lens
Authors: Poweleit CD , Menéndez J 
Published: July 2020

Abstract
Oil immersion lenses have been used in optical microscopy for a long time. The light’s wavelength is decreased by the oil’s index of refraction n and this reduces the minimum spot size. Additionally, the oil medium allows a larger collection angle, thereby increasing the numerical aperture. The SIL is based on the same principle, but offers more flexibility because the higher index material is solid. in particular, SILs can be deployed in cryogenic environments. Using a hemispherical glass the spatial resolution is improved by a factor n with respect to the resolution obtained with the microscope’s objective lens alone. The improvement factor is equal to n2 for truncated spheres.
As shown in Fig. 1, the hemisphere SIL is in contact with the sample and does not affect the position of the focal plane. The focused rays from the objective strike the lens at normal incidence, so that no refraction takes place.
Pharmaceutical Polymorphism Studies by Infrared Spectroscopic Imaging
Authors: Lewis Lori , Troost Peter , Lavery Donald , Nishikida Koichi 
Published: July 2020

Abstract
Many drugs are known to crystallize in different polymorphic forms or as solvates. Solubility, melting point, density, hardness, optical properties, vapor pressure, and a host of other physical properties may all vary with polymorphic form. Not only do the various crystal structures of a given pharmaceutical compound affect the efficacy of the drug, but they may also carry enormous legal implications. Much product revenue can depend upon the identification and patent protection of certain polymorphic forms. Thus, the control of crystallization is a very important process parameter, and techniques such as X-ray crystallography, infrared spectroscopy, Raman spectroscopy, and polarized light microscopy are routinely used in the characterization of crystalline drugs.
This presentation will involve the investigation of a variety of pharmaceutical polycrystalline films using infrared (IR) spectroscopic imaging. Preliminary data was collected using a conventional FT-IR microscope with visible polarized light capabilities. Correlating data was then collected using a commercially available IR imaging microscope.
Emerging Viral Hemorrhagic Fevers
Authors: Zaki Sherif R , Goldsmith Cynthia S 
Published: July 2020

Abstract
Clinically, the combination of fever and hemorrhage can be caused by many pathogens, including viruses, rickettsiae, bacteria, protozoans, and fungi. However, the term viral hemorrhagic fever (VHF) is usually reserved for systemic infections characterized by fever and hemorrhage caused by a special group of viruses that belong to four different families: Filoviridae, Arenaviridae, Bunyaviridae, and Flaviviridae. All members are lipid-enveloped RNA viruses; except for filoviruses, where the resorvoir remains unknown, these viruses are transmitted to humans by arthropods and rodents. The VHFs are characterized by abnormal vascular regulation and damage. The VHFs all have similar clinical pictures with mortality rates of 15-30% or in the case of Ebola virus, up to 80%. Between 1993 and 2001, more different VHFs and related diseases were reported than during any comparable period over the past several decades. These diseases include Ebola VHF in Uganda in 2000, in Zaire in 1995 and in Gabon between 1994 and 1996; ongoing cases of Marburg hemorrhagic fever in the Democratic Republic of Congo beginning in 1998; Rift Valley fever in Saudi Arabia and Yemen in 2000 and in Kenya in 1997; Lassa fever in Sierra Leone in 1997; hantavirus pulmonary syndrome in the Americas since 1993; and imported cases of dengue hemorrhagic fever from Central and South America, and yellow fever from Africa during the 1990s.
Polyomaviruses As Emerging Pathogens
Authors: Howell DN , Miller SE 
Published: July 2020

Abstract
Polyomaviruses are double-stranded DNA viruses of the family Papovaviridae. They replicate in cell nuclei, where they form 40-50-nm, non-enveloped, icosahedral nucleocapsids that exit the host cell by lysis (Fig. 1A-C). Polyomaviruses with pathogenic potential in both human and non-human hosts have been known for many decades. in recent years, however, new pathogenic polyomaviruses have been described in man, non-human primates, and other animals. New forms of acquired and iatrogenic immunocompromise have also led to changes in the prevalence and pattern of disease caused by well-characterized polyomaviruses. This presentation provides an overview of emerging polyomavirus diseases, illustrated with vignettes from our diagnostic practices. in many cases, the detection and monitoring of polyomavirus infections has been facilitated by ultrastructural examination.
Two well-characterized polyomaviruses cause disease in humans, almost invariably in the setting of immunosuppression. JC virus, described in 1971, is the causative agent for progressive multifocal leukoencephalopathy (PML), a generally fatal disorder characterized by patchy, progressive destruction of the cerebral white matter.
Intestinal Microsporidiosis
Authors: Marc Orenstein Jan 
Published: July 2020

Abstract
Sixteen years have passed since a microsporidian was first reported as an opportunistic pathogen in HIV/AIDS. to date, two new genera, Enterocytozoon and Trachipleistophora, and 5 new species, Enterocytozoon bieneusi, Encephalitozoon hellem and E. intestinalis, and T. hominis and T. anthropophthera have been described infecting patients with AIDS. E. bieneusi and E. intestinalis have been among the most common intestinal pathogens diagnosed as causes of diarrhea and wasting in HIV/AIDS.
Members of their phylum, Microspora, have in common a hollow polar tube that is tightly wound up in their spores. The coiling up of the polar tube, just beneath the cell wall, allows a structure that is several times its length to be packaged within a spore. E. bieneusi, which has the smallest of all microsporidian spores, 1 x 1.5 ¼m, overcomes its size limitations by packaging its polar tube in 2 layers of 3 coils each. When conditions are right, this unique structure is extruded from the spore and becomes the “needle of a syringe”.
Emerging and Reemerging Viral Pathogens: A Microscopic Overview
Authors: Goldsmith Cynthia S , Zaki Sherif R 
Published: July 2020

Abstract
During the 20th century, the advent of vaccines and antibiotics, and continued improvements in urban sanitation and water quality resulted in a dramatic decline in mortality due to infectious diseases. There was a brief period of optimism in the mid-1900's that infectious pathogens would no longer be a significant cause of death in the United States. For a number of reasons, this trend had reversed by the end of the century, and the rates of death caused by infectious diseases began rising. in recognition of this change, the Institute of Medicine issued a report in 1992 that called attention to the major factors contributing to the emergence and reemergence of infectious diseases. Among these were the following: increased human encroachment on wilderness habitats, resulting in changes in the ecosystem and increased contact with animal and insect vectors which may harbor unknown infectious agents; sizable growth in human population, resulting in increased urbanization and crowding; increased global travel; changes in human behaviors; and microbial evolution.
Detection of Early Cytomegalovirus Infection in Pathologial Specimens by H&E, IHC, ISH, Grocott’S and Modified Steiner Silver Stain for LM and EM: A Review
Authors: Chien K , Heathershaw ML , Heusser RC , Shiroishi H , Gonzalez R , Nast CC , Cohen AH 
Published: July 2020

Abstract
The diagnosis of cytomegalovirus (CMV) in tissue sections is usually quite easy because of the characteristic appearance of intranuclear inclusions. At times the morphological features are equivocal, the nuclear findings may be atypical or only a single cell may be affected, thereby creating uncertainty about the diagnosis. This report reviews our experience with the various microscopic techniques that can be used to make definitive identification of CMV.
EM - Visualizing the viral particles in a single or even lysed cell by routine electron microscopy can make the definite diagnosis, but section size limits the usefulness in the detection of early CMV infection (fig. 1). However, if a diagnosis can not be made with certainty by the following methods, EM can be performed on stained paraffin sections for confirmation.
H&E - A Hematoxylin & Eosin stain that discloses characteristic intranuclear inclusions surrounded by a clear halo indicates CMV infection (fig.2A).
Public Health Laboratory Preparedness; Bioterrorism the New Challenge
Authors: Meyer Richard F 
Published: July 2020

Abstract
In the event of a bioterrorist attack, rapid screening, agent identification, and confirmatory diagnosis will be critical, so that prevention and treatment measures can be implemented quickly. However, because few biologic agents thought likely to be used as biological weapons represent major public health problems in the United States, we have limited capacity to diagnose them, either at the state and local or the federal level. to begin to address this new public health challenge the Laboratory Response Network for Bioterrorism (LRN) was established.
The LRN is a multi-level system designed to link state and local public health laboratories, clinical, military, veterinary, agricultural, water and food-testing laboratories. Operational in August of 1999, the LRN was established as a consequence of Presidential Decision Directive 39, increased congressional awareness of the huge biological weapons program in the former Soviet Union, the high level of risk to national security and subsequent emergency funding to the Centers for Disease Control and Prevention under the DHHS Operating Plan for Anti- Bioterrorism Initiative.
Toward Quantitative Annular Dark Field Imaging
Authors: Vanfleet RR 
Published: July 2020

Abstract
Annular Dark Field imaging has the potential to be directly quantifiable. By this I mean that with careful measurement, the absolute image intensity has physical meaning. Unlike Bright Field TEM, the ADF image has no contrast reversals with focus and with the exception of thick specimens there are no contrast reversals with changes in thickness. Thus, image intensity is related to thickness, composition, orientation, and structure of local regions whose size is determined by the electron probe. The ability to extract quantitative information about the specimen from the intensity requires careful collection of the intensity data and a solid understanding of how that intensity will change with thickness, composition, orientation, and structure. The qualitative effect of thickness and composition has been well shown in the literature but more quantitative approaches have been lacking.
The simplest models of ADF imaging treat each atom interacting
Atomic-Scale Study of a Co/AlOx/Co Magnetic Tunnel Junction
Authors: Plisch MJ , Chang JL , Plisch MJ , Buhrman RA 
Published: July 2020

Abstract
Magnetic tunnel junctions (MTJ) which consist of two ferromagnetic electrodes separated by a thin (∼10Å) tunnel barrier can exhibit a magnetoresistance of greater than 40% at 295 K. They hold substantial potential for application as computer memory and magnetic field sensors. Much about the spin-dependent tunneling process is still not understood. in order to identify features that may affect the spin-polarization of the tunnel current, we have used the UHV STEM at Cornell University to perform atomic-scale imaging and EELS on an MTJ system. The MTJ was sputter deposited on (100) Si with layer sequence Co 60Å/Al 12AÅO2 exposure/Co 100Å.
The annular dark field (ADF) image (Fig. la) shows the A10x barrier layer has a fairly uniform thickness of about 15 Å. Its profile (Fig. 1c) appears diffuse partly due to layer roughness rather than atomic mixing. in bright field (BF) the appearance of strong Fresnel fringes (Figs. 1b,c), due to a large difference in average electrostatic potential between Co and AlOx, complicates interpretation.
Dopant Distribution Analysis in Carbon Nanotubes By Z-Contrast Imaging
Authors: Dickey EC 
Published: July 2020

Abstract
Similar to graphite and carbon fullerenes, the physical properties of carbon nanotubes (NTs) can be altered by ex-situ doping or by functionalizing the nanotube walls. Such mechanisms for tailoring the properties of carbon NTs expand their potential utility in electronic, optical and structural applications. Both acceptor (e.g. I2, Br) and donor-type (e.g. K, Rb) dopants have been successfully intercalated into single-wall NT (SWNT) bundles, and the transport properties of these doped species are greatly altered. For example, iodine-doped SWNTs exhibit a 40% decrease in DC conductivity. Doped SWNTs are a completely new class of nanostructured materials, and there is a large demand for understanding the structure of the various doped-compounds as well as the ramifications for the electronic properties of the material.
In this paper we demonstrate the utility of Z-contrast scanning transmission electron microscopy (STEM) for elucidating the structure of doped nanotubes.
Lorentz Stem: A Digital Approach to an old
Authors: Zaluzec Nestor J 
Published: July 2020

Abstract
The study of magnetic materials using electron column instruments has been a fruitful area of research for microscopists/microanalysts for nearly 4 decades. A number of techniques have been developed for both the SEM and TEM which enable visualization of magnetic fields ranging from Fresnel imaging (Fuller and Hale, Silcox), Differential Phase Contrast (Chapman), through to Electron Holography (Tonomura). The latter are generally qualitative, while the former quantitative, albeit at the price of significant complexity. The advent of microprocessor control of modern instruments, CCD detectors, and experimental diligence allows us to revisit and in fact revitalize this area of measurement.
The experimental work reported here is being carried out in the ANL AAEM HB603Z 300 kV FEG instrument. in this instrument, the electron optical column was operated in a zero field mode (figure 1), where the objective lens is turned off and the probe forming lens functions were reallocated to the C1, C2, and C3 lenses.
Complementary Structural Information from Diffraction Patterns in STEM: Accurate Thickness Measurement with Pattern Matching
Authors: Zuo J M , Shi YF 
Published: July 2020

Abstract
In this paper, we discuss the advantage of combining STEM imaging with diffraction. in addition, we present a set of accurately calculated convergent beam electron diffraction (CBED) patterns for Si, which highlights the sensitivity of electron diffraction to structure. The calculation takes the full account of crystal bonding by including known experimental structure factors in simulation. Such calculated patterns can be used for accurate determination of the sample thickness, crystal orientation and polarity (for acentric crystals). Calculations with and without crystal bonding show significant difference in calculated intensities, equivalent to a change in thickness about several nanometers for thick samples.
The annual dark field (ADF) imaging mode in scanning transmission electron microscopes offers the unique advantage of combining high-resolution electron imaging and spectroscopy with diffraction. The large cutoff angle used in ADF imaging allows simultaneous recording of diffraction patterns for quantitative structural information, while ADF imaging gives the precise position of the probe and the image of the sample.
A Sub-Ev Resolution Soft-X-Ray Spectrometer for a Transmision Electron Microscope to Obtain the Density of States of the Valence Band
Authors: Terauchi M , Yamamoto H , Tanaka M 
Published: July 2020

Abstract
We developed a high energy-resolution electron energy-loss spectroscopy (EELS) microscope to investigate electronic structures from specified small specimen areas [1]. EELS gives us information of the dielectric properties and the partial density of states (DOS) of the conduction band. Together with the DOS of the conduction band (unoccupied states), the DOS of the valence band (occupied states) is imperative to understand the whole electronic structure. Unfortunately, the DOS of the valence band cannot be reached directly by EELS.
A partial DOS of the valence band can be obtained by fluorescent X-ray emission spectroscopy (XES). A conventional EELS instrument attached to a TEM usually takes spectra with an energy resolution of about 1 eV, by which the DOS of conduction bands has been studied using ELNES until now. Thus, an energy resolution of about 1 eV is at least necessary for the study of the DOS of the valence band.
Exit Wave Reconstruction of Interfaces Between Zno Films and ScalmgO4 Substrates
Authors: Wessler B , Steinecker A , Mader W 
Published: July 2020

Abstract
Epitaxial ZnO thin films were produced on basal plane ScAlMgO4 (SAM) by chemical solution deposition (CSD) (fig. 1). ZnO crystallizes in the wurtzite structure and ScAlMgO4 is isostructural to YbFe2O4, a layered structure shown in fig. 2. The crystallographic orientation relationship was observed by XRD using θ-2θ scans and off-axis φ scans to be (0001)zno ∥ (0001)SAM and zno ∥ SAM. The lattice mismatch between film and substrate is 0,09%.
For TEM observations in cross-sectional geometry two substrates were glued together with the epitaxial film surfaces. Electron transparent specimens were produced by standard methods of mechanical thinning and ion beam etching. The HRTEM investigations were performed on a Philips CM300 FEG electron microscope with Ultra-Twin lens operated at 300 kV. After correction of axial coma and two-fold astigmatism images were recorded on a slow-scan lk × lk CCD camera with a sampling of 0.0193 nm/pixel.
Radial Distribution Function of Tin Thin Film Adjusted by Experimental Phase Shifts
Authors: González-Valenzuela C , Espinosa-Magaña F , Martínez-Sánchez R , Duarte-Möller A 
Published: July 2020

Abstract
Titanium Nitride thin film was obtained by the DC-Sputtering technique and characterized using the transmission EXEELFS formalism. The experiments were performed in a CM 200 transmission electron microscope with a GAT AN 766 PEELS attachment. A primary energy of 200 keV and a spot size of 440 nm with an average acquisition time of 5 min were used. The atomic distribution obtained using EXEELFS was corrected with the respective experimental phase shifts. Atomic parameters were compared with those corrected by EXAFS phase shits and the known crystallographic values.
The energy loss spectra for the sample, around the ionization Ti L23-edge and N K-edge corrected for background and multiple scattering process is shows in Figure 1. N K-edge appears at an energy loss of 400.4 eV and the Ti L23-edge is located at an energy loss of 464.3 eV. These values on energy are shifted 0.6 eV respect to the isolated transitions.