bluuebunny/crossref_metadata_2025_split huggingface dataset:
Self-Assembly of Dynamin
Authors: Danino Dganit , Hinshaw Jenny E 
Published: July 2020

Abstract
Dynamin is a large GTPase essential for various intracellular processes such as synaptic vesicle recycling, caveolae internalization and trafficking into and out of the Golgi. It is also involved in receptor-mediated endocytosis, and is believed to assemble at the necks of clathrin-coated pits and assist in pinching vesicles from the plasma membrane upon GTP binding and hydrolysis.
Purified recombinant dynamin self-assembles into rings and spirals in low salt conditions [1]. A dynamin mutant lacking the c-terminal proline rich domain (APRD) also assembles into rings and spirals, however unlike wild type dynamin APRD constricts in the presence of GTP analogous such as GMP-PCP [2] or GTPγS. to explore differences in the behavior of the wild type and mutant dynamin we dialyzed them into different salt solutions containing various types of nucleotides and studied their assembly over time using negative staining and cryo-TEM.
The Power of Freeze-Fracture Technique in Electron Microscopy
Authors: Papahadjopoulos-Sternberg B 
Published: July 2020

Abstract
In the early 1960s, concerns about artifacts in preparing biological material for electron microscopy led to a new technique whereby samples are rapidly frozen, fractured under high vacuum, the fractured surfaces shadowed and replicated with a thin metal-carbon coat, and the cleaned replica examined in a transmission electron microscope. Pioneered by Moor and Muhlethaler subcellular structures are revealed with extraordinary three-dimensional clarity at near-molecular resolution. Furthermore, it was observed and proven at model systems as well as biological membranes that lipid bilayers split along their hydrophobic interior during freeze-fracture procedure. Therefore, freeze-fracture electron microscopy (FFEM) has the unique advantage of accessing the hydrophobic interior of biological (FIG.l, 5 and 6) as well as artificial bilayers (FIG. 2, 4, 5, and 6). Here it permits study of pattern generated by intrinsic proteins as well as lipids (FIG. 1 and 2).
The Development of a Holey Metal Oxide Support Film for High Temperature “Ex-Situ” Tem Oxidation Studies
Authors: Kliewer CE , Varon J , Malek A , DeMartin GJ 
Published: July 2020

Abstract
Transmission electron microscopy (TEM) has traditionally served as an important tool for understanding the physical properties of many materials. Recent improvements in “ex-situ” techniques have further strengthened the role of TEM as a unique characterization method.
The use of ExxonMobilfs dedicated reactor system for studying metal oxidation at moderate temperatures has been reported. However, high temperature oxidation studies have been limited by the use of holey carbon support films, which oxidize and disintegrate during these experiments. Consequently, a new method was developed to replace the holey carbon support film with a holey metal oxide support film that both maintains its structural integrity during high temperature oxidation and remains electron transparent.
The new support film was prepared using a commercially available, holey carbon coated TEM grid as a template (Figure 1). An Al metal film (∼10nm thick) was deposited onto the holey carbon coated side of the TEM grid using a magnetron sputtering system.
Preparation/Dispersion of Small Particles for TEM Study
Authors: Foo Kit h , Chiou W-A , Ishikawa A , Fukushima K , Meshii M 
Published: July 2020

Abstract
Small particles such as clay minerals, because of its large surface area to volume ratio and their high chemical activity on the particle surface, when added to composites affects (and often enhances) the physical, chemical and mechanical properties of materials immensely. As a result, there is a need to develop a method of characterizing these particles individually. However, physical dispersion of these particles can be very difficult, since they tend to agglomerate to reduce the high surface energy. Disperants of various sorts could be used to disperse/stabilize the system, but they could compromise/damage the integrity of the inherent state of these small particles. This paper presents a comparison study of preparing/dispersing small clay particles for electron microscopy research, and also represents the first report of cryo-microscopy of clay minerals.
Two types of smectites, namely a montmorillonite with cation exchange capacity (CEC= 140) and a saponite (CEC=42) were used for this study.
Thickness Measurements of DLC Films by EELS and Electron Holography
Authors: Musashi T , Ikematsu Y , Shindo D , Nakamura N , Oikawa T 
Published: July 2020

Abstract
Diamond-like carbon (DLC) has been used as thin films to protect the surface of magnetic disks in hard disk drives. Recently, in order to improve the recording density of the hard disks, DLC films need to be thinner than 10 nm in thickness. Therefore, it is necessary to develop the accurate thickness measurement technique for thin DLC films. in this study, to establish the thickness measurement technique for DLC films using electron energy-loss spectroscopy (EELS) and electron holography, we estimate the mean free path for inelastic scattering (ƛp) and the mean inner potential (U0). Through the evaluation of ƛp and U0, we compare the accuracy of EELS and electron holography on thickness measurement of DLC films.
The DLC films in this study are deposited on silicon wafers by chemical vapor deposition (CVD), sputtering and ion beam deposition (IBD) methods.
Adhesion Strength of Cu-Ni Multilayered Coatings on Optical Fibers
Authors: Lin Yuli , Hwang Li-Jang 
Published: July 2020

Abstract
Optical fibers have been extensively employed in a variety of fields. However, the need of high strength, excellent resistance to moisture permeation and tolerance to heat becomes apparent when such optical fibers are used in nuclear power plants and chemical plants in particular. Plastic coatings as conventional made of optical fibers cables would be replaced by the optical fiber coated with layers of metals.
The adhesion of coating to substrate is a critical property of any coating system for mechanical integrity and environmental protection of the substrate. For example, the corrosion protection of the metal coated optical fibers is highly depend on the adhesion of the coatings, if adhesion is poor, the extent of deterioration of the substrate by environmental factors (humidity, corrosive gases, etc.) is greatly accelerated. The durability and longevity of a coating required that its adhesion is to be maintained [1].
Magnetic Domains and Domain Wall Pinning in Nanocrystalline Ni-P
Authors: Zhang JP , Guo YX , Speck JS 
Published: July 2020

Abstract
Magnetic domain structures in a Ni-5at%P alloy have been examined using Lorentz microscopy in Fresnel mode in a JEOL 2010TEM. with electron diffraction and high resolution electron imaging, the Ni-P alloy material is seen to be of FCC structure and composed of nanometer-sized grains (&lt; 4nm in diameter), which is about 2 orders less in size than that of a single magnetic domain.
The TEM specimen was prepared using jet polishing method. Before introducing the specimen into the microscope, the objective lens was turned off in a free lens control mode to ensure that the domain structures in the specimen remain unaffected. The objective mini-lens was used to perform Lorentz imaging with out-focus method.
Stripe domains were observed. The width of these stripes is about 0.2 micron. But the length of these domains varies, sometime up to several microns. The stripe domains are grouped, which are near parallel one to the other.
Analytical Electron Microscopy of V-4%Ti-4%Cr Alloys
Authors: Bentley J , Pint B A 
Published: July 2020

Abstract
An important aspect in the consideration of V-4%Ti-4%Cr alloys as structural materials for proposed fusion reactors, especially for weldments, is the sensitivity of mechanical behavior to oxygen content. Following a 1-h anneal at 1200°C, sheet specimens were subjected to extended (16h to 43h) anneals at 500°C in 5 to 8 x 10-6 torr oxygen, followed by an homogenization vacuum anneal of 100 h at 600°C. Weight gains indicated ∼200 to &gt;1400 wppm oxygen doping. Specimens were also subjected to an additional vacuum anneal for 4 h at 950°C. Specimens were prepared by standard double-jet electropolishing for TEM characterization with a Philips CM30 (LaB6) equipped with a Gatan Imaging Filter (GIF), and with a Philips CM200FEG equipped with Oxford EDS, GIF, and Emispec Vision integrated acquisition system.
Following oxygen doping and homogenization, high concentrations of nanoscale G.P.-zone-like clusters on ﹛001﹜ were observed in the matrix, with a ∼200-nm-wide precipitate free zone (PFZ) at grain boundaries.
The Determination of the Orientation Relationship Between Primary and Eutectic Aluminum in A.Cast 319 Aluminum Alloy
Authors: Donlon WT , Zindel JW 
Published: July 2020

Abstract
Cast 319 aluminum is an important automotive alloy used for engine blocks and cylinder heads. in order to “optimize” the as-cast microstructure and physical properties, a detailed understanding of its solidification behavior is required. One aspect of the solidification behavior which is not well understood is the mechanism by which aluminum and silicon in the eutectic regions nucleate. Figure 1 is an optical micrograph which identifies the aluminum dendrites, the Al-Si eutectic region, iron intermetallics, and Al2Cu particles. Dahle, Hjelen & Arnberg have utilized electron backscattered diffraction (EBSD) patterns, obtained with an SEM, on several Al-Si alloys to examine the orientation relationship between the aluminum in the eutectic to that of the surrounding aluminum dendrites. in this investigation transmission electron microscopy (TEM) is used to provide a more detailed examination of this eutectic structure while selected area diffraction (SAD) provide similar data to EBSD on the orientation relation between regions of primary and eutectic aluminum.
Phase Transformations in β- Phase Cuzn Single Crystals Induced By Ion Irradiation
Authors: Tolley Alfredo J , Sanchez Esteban A 
Published: July 2020

Abstract
The high temperature equilibrium β phase in Cu-based alloys has a disordexed bcc structure. Its stability at high temperatures is due to the large amplitude ﹛0 ζ ζ)﹜ &lt;0 ζ ζ&gt; soft mode which provides a large vibrational entropy. This stability decreases with temperature as the entropy term in the Gibbs free energy becomes smaller. However, by quenching it is possible to retain the β phase avoiding decomposition by diffusion controlled transformations. in ternary β phase Cu-Zn- Al alloys, ion irradiation at room temperature has been reported to induce a phase transformation to a close packed structure or to produce γ phase precipitates. in order to further study the tendency of the β phase to decompose into other phases at room temperature, ion irradiation experiments in binary Cu-Zn single crystals were carried out using a beam of 30 keV Ar ions. The changes in the microstructure were examined using transmission electron microscopy.
Medium-Range Order in Metallic Glasses Studied by Fluctuation Microscopy
Authors: Li Jing , Gu Xiaofeng , Hufnagel T C 
Published: July 2020

Abstract
Atomic structure on the 1-2 nm scale, often referred to as “medium-range order” (MRO), is of great importance for understanding the properties of disordered materials. It is, however, difficult to adequately characterize medium-range order. Fluctuation microscopy is a newly developed TEM technique that has successfully been employed to characterize MRO in amorphous semiconductors. The predominance of highly directional covalent bonds leads naturally to the presence of MRO in amorphous semiconductors. For metallic glasses, however, the bonding is primarily metallic and nondirectional. Thus, it is not readily apparent whether MRO would exist, or whether fluctuation microscopy is a useful tool for studying the structure of metallic glasses. in this work we report the use of fluctuation microscopy to identify differing degrees of MRO in Zr-based bulk metallic glasses; the MRO depends on the alloy content and the method of TEM specimen preparation.
Phase Identification in Melt Spun Mg-1.5%wtCa-6%wtZn Alloy Using Electron Diffraction and HREM
Authors: Jardim PM , Solórzano IG , Vander Sande JB , You BS 
Published: July 2020

Abstract
In recent years there has been a significant increase in magnesium use as a structural material. Applications include aerospace and automotive industries as well as appliances and sporting goods. The most attractive feature about magnesium alloys is related to their low density. However, their mechanical properties require improvement to surpass the specific strength of the high strength aluminum alloys. The purpose of the present paper is to report the crystal structure determination of the precipitates found in the alloy Mg- 1.5%wtCa-6%wtZn produced by melt spinning.
The as solidified alloy was analyzed by means of Transmission Electron Microscopy(TEM), Scanning Transmission Electron Microscopy (STEM) and Energy Dispersive X-ray Spectroscopy (EDS). The crystal structure of the new precipitate observed was determined by means of comparison of experimental and simulated selected area electron diffraction patterns (SADP) and High Resolution Electron Microscopy (HREM) images. The simulations were obtained using the software EMS.
The Atmosphere and Milling Devices Effect on the Activation Energy for Crystallization of a Partially Amorphized Ni-MO Alloy
Authors: Martínez-Sánchez R , Estrada Guel I , Béjar-Gómez L , Espinosa-Magaña F , Jaramillo Vigueras D , Duarte Moller A , Diaz de la Torre S 
Published: July 2020

Abstract
Although amorphous phases produced by mechanical alloying (MA) in the Ni-Mo system have been reported before. It has not been presented the influence of using different milling devices and atmospheres. This work is focused to the characterization of amorphous structures thus obtained in a Mo-47 at. % Ni alloy. Selected composition corresponds to the equiatomic NiMo intermetallic. The characterization was carried-out by XRD, SEM-EDS, DSC and TEM. High resolution XRD reveals that the MA′ed products undergo partial amorphization, as shows Figure 1. The main difference in the patterns is a region that corresponds to typical Nickel reflections. Nickel preferential amorphization after milling was evident. Apparently, a major grade of amorphization was attained when using the Simoloyer mill. A rough crystallite size was calculated using Scherrer equation, which reveals that this parameter reached its minimum value with the Simoloyer mill. During DTA analysis, it was observed the presence of an exothermic peak in all samples.
Quantification of CeO2 Reduction By In Situ Electron Energy-Loss Spectroscopy
Authors: Sharma Renu , Crozier Peter 
Published: July 2020

Abstract
CeO2 is an important material in many catalyst applications. CeO2, PrO2 and TbO2 are the only lanthanides known to exist as oxides in both 3+ and 4+ oxidation states. The high oxygen mobility at low temperature (≈300°C) results in easy oxidation-reduction cycles; a property utilized in the catalyst industry, especially for CeO2. Studying the oxidation-reduction behavior is thus very important to understanding the reactivity of CeO2 as a catalyst. We have studied CeO2 by in situ electron diffraction, high resolution electron microscopy (HREM) and electron energy-loss spectroscopy (EELS), not only to understand the reduction behavior but also to develop a method to quantify the reducibility of CeO2 or mixed oxides containing CeO2 by EELS. We have applied this method to study the behavior of ZrO2-CeO2 catalyst during reduction.
Experiments were performed on a PHILIPS-430 electron microscope operated at 300KV, fitted with a differentially pumped environmental cell and a Gatan Imaging Filter (GIF).
Deactivation of PT / Zeolite-L Catalysts Studied by Z-Contrast
Authors: Treacy M M J 
Published: July 2020

Abstract
When Pt particles of sub-nanometer dimensions are inserted into the linear channels of the potassium ion form of zeolite L, the resultant Pt/KL catalyst converts linear n-C6 hexane into cyclic C6 benzene with remarkable efficiency [1,2].
However, a drawback to Pt/KL catalysts is that they are exquisitely sensitive to sulfur contamination in the n-hexane feed. The catalyst deactivates rapidly when there are trace amounts (&gt; 50 parts per billion) of sulfur in the feed. Bright field TEM studies show that the Pt particles remain finely dispersed within the channels after sulfur poisoning, with typical particle widths &lt; 1.5 nm, implying that a large percentage of the Pt atoms still reside on the surfaces of the particles. For heterogeneous catalysts such as Pt/γ-alumina, where the Pt particles are always readily accessible on the external surface of the alumina support, such sulfur concentrations are tolerated.
Improved Methanol Oxidation Activity Through Oxidation-Induced Phase Separation of PtRu Electrocatalysts
Authors: Stroud RM , Long JW , Swider KE , Rolison DR 
Published: July 2020

Abstract
Direct methanol fuel cells (DMFCs) offer a simpler, safer technology for point-of-use power sources compared to other hydrogen fuel cells, by avoiding the need to store hydrogen fuel or to carry out the reformation of hydrocarbons. The direct methanol oxidation electrocatalyst of choice is a nanoscale black consisting of a 50:50 atom % mixture of Pt and Ru. It has recently become known that these presumed bimetallic alloys in fact contain an array of metal, oxide and hydrous phases, which are easily misidentified in routine x-ray diffraction measurements due to particle size-broadening and poor crystallinity. By combining transmission electron microscopy, electrochemistry and thermogravimetric studies, we demonstrate here that the route to improved catalytic activity is not by phase purification of the bimetallic alloys, but instead phase engineering of hydrous ruthenium oxide and Pt mixtures.
STEM Observation and EELS Analysis of Dopant and Catalyst Particles in Carbon Nanotubes
Authors: Fan X , Dickey EC , Puretzky AA , Geohegan DB , Pennycook SJ 
Published: July 2020

Abstract
Doping carbon nanotubes with either electron donors or acceptors can improve their electrical conductivity [1-2]. In order to fully understand the doping mechanisms and the corresponding changes in the electronic properties, it is essential to reveal the spatial distribution of the dopants within the carbon nanotubes. In this study we have investigated both iodine- and bromine-doped single wall carbon nanotubes(SWNT) by Z-contrast scanning transmission electron microscopy (STEM). The SWNT bundles were made by arc-discharge method and doped with either molten iodine or bromine vapor. Both iodine and bromine were incorporated linearly within the nanotube bundles as shown in Fig. l and Fig.2 respectively. Higher resolution images of iodine doped nanotubes reveals that two iodine atomic chains are inside each individual SWNT as shown in Fig. lc. This unexpected result is contrary to the common belief that dopants can only enter interstitial site of the SWNT bundles.
Silicon Oxynitride Film Thickness Measurements Using HRTEM and Grazing Incidence X-Ray Photoelectron Spectroscopy (GIXPS)
Authors: Scott John Henry J , Landree Eric W , Jach Terrence , Windsor Eric S 
Published: July 2020

Abstract
The ability to accurately and precisely measure the thickness of ultrathin (∼ 3 nm) dielectric films, used as gate dielectrics in integrated circuits, is critical to the continued success of the semiconductor manufacturing industry. Many metrology tools have been applied to this problem in the past, but recent research has focussed on ellipsometry, x-ray reflectivity, secondary-ion mass spectrometry, capacitance-voltage curves, medium energy ion scattering, high resolution transmission electron microscopy (HRTEM), and grazing incidence x-ray photoelectron spectroscopy (GIXPS). Unfortunately, these techniques disagree about a given film's thickness by amounts larger than their individual precisions. To support the statistical process control methodologies used in production wafer fabrication, these disagreements need to be investigated and the true accuracy and precision of the tools need to be determined. This work compares the ability of two techniques, HRTEM and GIXPS, to measure the thickness of silicon oxynitride films on silicon substrates.
Carbon Filament Growth on Fully Formulated Pd/Rh Automotive Catalysts
Authors: Hangas JW , Graham GW , McCabe RW , Chun W 
Published: July 2020

Abstract
Automotive exhaust catalysts are typically operated under stoichiometric conditions to minimize nitrogen oxide, hydrocarbon, and carbon monoxide pollutants. These catalysts do not form carbon filaments under normal operating conditions. In development of catalysts, however, a stabilization procedure is sometimes utilized on used catalysts (dynamometer or vehicle) to purge the catalyst of sulfur prior to measuring the catalytic activity in sweep and light-off testing. The stabilization procedure consists of running the catalyst under rich (excess fuel) conditions for 0.5hr. This study documents the existence of carbon filaments due to the stabilization procedure and discusses the effect of filaments on subsequent testing.
Two separate catalysts were used in this study. The first was a 50,000 mile vehicle aged catalyst that had also been through the stabilization procedure and then sweep and light-off tested. The other was only dynamometer aged for 120hr at 850°C (1560°F).
Partial Amorphization in a Ni-Mo Alloy by Mechanical Alloying
Authors: Martínez-Sánchez R , Duarte-Möller A , Facundo-Almeraya M , Paraguay-Delgado F 
Published: July 2020

Abstract
In the last decades, amorphous alloys have been the focus of many researchers around the world. Rapid solidification is one of the most employed techniques in obtaining amorphous structures. Important limits of this technique are the high melting point alloys, and in many cases it is restricted to compositions near eutectic deeps. By mechanical alloying it has been possible to obtain amorphous structures in several alloy systems, and in compositions different to eutectic points.
Amorphous phases by mechanical alloying in the Ni-Mo system has been reported before. This work is focused to the characterisation of amorphous structures obtained by mechanical alloying in a Mo-47 at. % Ni alloy. This composition corresponds to the equiatomic NiMo intermetallic. The characterisation was carried-out by XRD, SEM-EDS, DSC and TEM. Full amorphization was obtained after 32.4 ks of milling in a Simoloyer ball mill, as shows conventional XRD, Figure 1.
Assembly Of Myofibrils in Vertebrate Cross-Striated Muscle Cells
Authors: Sanger J W , Sanger J M 
Published: July 2020

Abstract
This presentation will review how myofibrils are formed in both types of vertebrate cross-striated myofibrils, i.e., cardiac and skeletal muscle.
Cardiomyocytes isolated from 7 to 9 day-old chick embryos and myoblasts isolated from 10-day old quail embryos were placed in tissue culture. The cardiac cells were allowed to spread in culture for 3 - 5 days. Similarly, the myoblasts were permitted to fuse to form myotubes which were then fixed at different points of elongation over 3 -5 days. Some cultures were fixed and stained with antibodies (e.g., sarcomeric isoform of alpha-actinin; non-muscle myosin IIB and muscle myosin II) to detect the disposition of the forming and mature myofibrils inside these cells. Sister cultures were transfected with plasmids expressing Green Fluorescent Protein (GFP) ligated sarcomeric proteins like alpha-actinin. The staining and transfection results revealed that three different types of fibrils form during myofibrillogenesis: premyofibrils, nascent myofibrils and mature myofibrils (1-2).