bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electron Energy-Loss Spectroscopy (EELS) of Fe-Bearing Olivine and Laihunite (an Oxidized Olivine)
Authors: Xu Huifang , Fu Pingqiu 
Published: July 2020

Abstract
Laihunite that has distorted olivine-type structure with ferric and ferrous irons and ordered distribution of vacancies was first discovered in a high-grade metamorphosed banded iron formation (BIF) [1, 2]. The laihunite coexisting with fayalite (Fe-olivine), magnetite, quartz, ferrosilite, garnet and hedenbergite, formed in the process of oxidation of fayalite [2, 3]. The structure refinement of 1-layer laihunite shows P21/b symmetry and ordered distribution of vacancies in half M1 sites of olivine structure [2, 3]. Early high-resolution transmission electron microscopy (HRTEM) study and HRTEM image simulation of the 1-layer laihunite verified the structure refinement [4].
Specimens of weakly oxidized fayalite and laihunite containing fayalite islands collected from Xiaolaihe and Menjiagou of Liaoning Province, NE China, have been studied using selected area electron diffraction (SAED), high-resolution transmission electron microscopy (HRTEM), electron energy-loss spectroscopy (EELS), and X-ray energy-dispersive spectroscopy.
Reflection Extended Electron Energy Loss Fine Structure (REXEELFS) Study Of Damage Induced By Ar+ on Hopg (0001) Surface.
Authors: Duarte-Moller A , Espinosa-Magaña F , Martínez-Sánchez R 
Published: July 2020

Abstract
In recent years much attention has been paid in development of EXEELFS (EXELFS, EELFS) technique.Some people around the world focused their work in characterizing materials in both, reflection and transmission geometries [ 1-2]. These studies show that EXEELFS technique is a reliable way to obtain the local structure of these materials. Some authors have been done experiments to detect structural changes on the surfaces (epitaxial grown, small clusters grown, surface reconstruction, etc, ). In this paper we have done a systematical observation of the possible damage induced by the Ar+ ions on HOPG surface at different sputterin times
Experiments were taken at room temperature in a commercial UHV chamber for surface analysis, with a base pressure of 2.5 x 10-10 Torr. A PERKIN ELMER PHI-595 scanning Auger microprobe with single pass Cylindrical Mirror Analyzer. (CMA), and coaxial election gun which can operate from 1 KeV to 10 K eV, equipped with Ar ion gun system for cleaning surfaces was used.
3D Reconstruction of Na+, K+-ATpase from Tubular Crystals
Authors: Rice W J , Young HS , Martin DW , Sachs J R , Stokes DL 
Published: July 2020

Abstract
The Na+,K+-ATPase is a transmembrane protein, located in the plasma membrane of virtually all animal cells, which controls Na+ and K+ gradients. It is a member of the P-type ATPase family of ion pumps, a group of enzymes which pump ions against a concentration gradient, forming a phosphorylated intermediate during the pumping cycle. For each mole of ATP hydrolysed, 3 Na + ions are moved out of the cell and 2 K+ ions are moved into the cell. Unlike most other members of this family, which have one subunit, Na+, K+-ATPase is a heterodimer of α and β subunits. The a subunit consists of 1020 amino acids and has been predicted to have 10 membrane-spanning a-helices as well as a large cytoplasmic headpiece which forms the ATP binding and phosphorylation site. The α subunit, 300 amino acids in length, has one membrane spanning helix and has most of its mass located on the extracellular side of the membrane.
3D Reconstruction from STEM Images of Xanthine Dehydrogenase and Insulin Receptor: Refinements and Molecular Modelling.
Authors: Beniac DR , Luo RZT , Fernandes AB , Iwasaki T , Yip CC , Ottensmeyer FP 
Published: July 2020

Abstract
We have reconstructed the three-dimensional quaternary structure of the complete 480 kDa insulin receptor (IR), complexed with Nanogold - labeled insulin, and the 290 kDa Xanthine Dehydrogenase (XDH). Both molecules were imaged by low-dose, low-temperature dark field scanning transmission electron microscopy (STEM). XDH and IR were both freeze-plunged in liquid ethane, and transferred to the STEM (VG HB 601) where they were freeze dried at -130°C. Reconstruction was carried out using the method of quaternion-assisted angular reconstruction (IQAD) as described previously. XDH was further refined by an iterative process in which the IQAD produced volume was used as a reference for further refinements. Separate reconstructions of two sets of half the images indicated an inter-reconstruction resolution of 20 Å and 9 Å by phase residual criteria for the IR and XDH reconstructions, respectively.
Cryo-Electron Microscopy Training at the Wadsworth Center
Authors: Grassucci Robert A , Frank Joachim 
Published: July 2020

Abstract
Training of students, postdocs and scientists in the techniques and instrumentation of Cryo-electron microscopy has many challenges. This is especially the case at the Wadsworth center where there are a variety of techniques as well as instruments to choose from, each of them having certain nuances that need to be recognized before they can be fully taken advantage of. There are also users with many levels of experience that need to be trained to use the equipment and techniques effectively. For this reason we have chosen to incorporate many of the protocols which are used into an internal web page. The web browser is a very effective tool for conveying detailed information on a variety of levels.
A novice user is asked to go through the EM training web page (Figure 1) and then select the Philips EM420 use link to get a feel for the steps that will be involved to set up and operate the microscope.
Macromolecular Structure Visualization Tools at NCMI
Authors: Dougherty Matthew , Chiu Wah 
Published: July 2020

Abstract
Sophisticated tools are needed to examine the results of cyro-microscopy. As the size and resolution of three dimensional macromolecular structures steadily improve, and the speed at with which they can be generated increases, researchers are finding they are inundated with larger datasets and at the same time are compelled to expediently evaluate these structures in unforeseen ways. Integration of EM data with other types of information is becoming necessary and routine; for example X-ray data, 3D EM reconstructions, and theoretical models, must be evaluated in concert to discount or propose hypothesis. To create such tools, the developer must take into account not only the empirical and theoretical possibilities, but also they must master the human factors and computational limits. During the last five years, the National Center for Macromolecular Imaging (NCMI) has progressed from a remedial 3D visualization capability to a collection of visualization tools allowing researchers to focus on the discovery phase of biological research.
Bacteriophage PRD1 Capsid Structure: Iterative Combination of Threedimensional Electron Microscopy and X-Ray Crystallography
Authors: Martin Carmen San , Burnett Roger M , Haas Felix de , Heinkel Ralph , Rutten Twan , Fuller Stephen D , Butcher Sarah J , Bamford Dennis H 
Published: July 2020

Abstract
PRD1 is a ds-DNA bacteriophage from the Tectiviridae family with an unusual structural feature: the viral genome is enclosed by a protein-rich membrane, which is in turn enclosed by an external icosahedral protein shell (capsid). Three-dimensional reconstructions from cryo-electron microscopy (cryo-EM) images have revealed the structure of the PRD1 capsid at moderate resolution (28 Å), while X-ray crystallographic studies have recently provided a high resolution (1.85 Å) picture of the major coat protein, P3. We have now combined these results from different imaging methods to obtain a more detailed understanding of the virion organization. The combination has been made in a cyclic process: a preliminary fitting of the atomic structure of P3 to each one of its independent positions in the cryo-EM maps of the capsids provided initial models that could be used to improve the reconstructions; the refined maps then served as a base frame for an optimized fit. This process allows us to study the viral particle structure at “quasi-atomic” resolution.
Cytoskeleton-Organelle Interaction: Higher Plant Chloroplasts Are Contained In Actin Baskets And Attached To Actin Filaments And Bundles
Authors: Kandasamy MK , Meagher RB 
Published: July 2020

Abstract
Plant organelles, including the dominant chloroplasts, migrate intracellularly on cytoplasmic strands (Fig. 1A-D). The chloroplasts in the leaf cells orient and redistribute in response to light to ensure maximum photosynthetic productivity. Their orderly distribution is also essential for proper transmission of organelle genome during cell proliferation. The movement and positioning of chloroplasts have been suggested to be mediated by the actin and tubulin-based cytoskeleton in green algae and higher plants. However, the actin structures controlling these processes have not been clearly delineated because of the difficulty in preserving and detecting the fine actin filaments in plant cells using conventional fixation methods and currently available antibodies.
We investigated the role of the actin cytoskeleton in the regulation of chloroplast movement and positioning by studying: 1) the structural relationships of microfilaments and chloroplasts in leaf cells of Arabidopsis; and 2) effects of an anti-actin drug, Latrunculin B (LAT-B), on intracellular distribution of chloroplasts.
Routine High Resolution Cryo SEM Applied to Medical, Cosmetic, Health Care, Pharmaceutical and Food Industries.
Authors: Robins Alan 
Published: July 2020

Abstract
The value of a Cryo SEM system, attached to a conventional SEM, has already been demonstrated in the biological, pharmaceutical, oil, paint, plastics and food industry. Specimens are first rapidly frozen to below -160°C, transferred under vacuum to a cryo preparation chamber, fractured and examined at low KV (uncoated ) in the SEM. The sample is then usually etched, sputter coated and finally examined at 5-15KV. On conventional microscopes, successful cryo images can be obtained at 30,000 - 50,000X magnification at high KV.
With the invention of field emission gun technology, much higher resolution is now achievable at a lower KV. This allows higher resolution information to be visualised from the surface of the sample. To allow this successful resolution, with the low atomic number samples mentioned above, we have to put down a fine grain, artefact free coating of high atomic number material to prevent charging and help reduce beam penetration.
Immunoprobe Localization by Correlative Microscopy: How Much Resolution is Enough?
Authors: Calarco Patricia G 
Published: July 2020

Abstract
With the advent of new ways to image biological material, to tag biological molecules, and to prepare samples, much progress has been made in understanding cellular and subcellular function without resorting to classical electron microscopy. Newer ways to image include the use of microscopies such as: differential interference, video, confocal, near field scanning optical, and magnetic resonance imaging. The use of tags such as cell-permeant organelle-specific markers and green fluorescent protein has further increased our ability to vision subcellular events in living cells, providing us with functional correlations of gene activity and cellular function in a number of biological systems. Techniques such as high pressure freezing coupled with freeze substitution have expanded the range of tissues and organisms that can be optimally preserved and are changing our understanding of cellular fine structure. However, even when electron microscopy is mandated, 1-2 angstrom resolution is rarely indicated except for investigations of molecular structure.
Immunoelectron Microscopy of Keratinocytes: an Improved Protocol for Flat Embedding of Cultured Cells Using Lowicryl K4M
Authors: Bauer C , Vasioukhin V , Yin M , Fuchs E 
Published: July 2020

Abstract
In cell culture models various and distinct manipulations can be performed in a defined environment. This makes cell cultures very popular for immunohistochemical studies. Such studies are mostly performed at the light microscopic level where fluorescent probes and confocal microscopy provide detailed insights into the distribution and localization of antigens inside cells. In many such cases further studies at the electron microscopic level would give additional information and an often more detailed view. As compared to light microscopy not only is the resolution much higher, but also and even more importantly labeling information is completed with a wealth of cytological details.
This said it is surprising that studies on cell cultures using immunoelectron microscopy are rarely seen. Even more rare are reports in which monolayer cells are fixed and processed in situ without prior trypsinization. Such studies are essential though when cytoarchitecture is of importance or especially when cell-cell adhesion is an issue.
Nucleation of Proeutectoid Ferrite on Complex Precipitates in Austenite
Authors: Furuhara Tadashi , Yamaguchi Jun , Maki Tadashi 
Published: July 2020

Abstract
Proeutectoid ferrite (bcc α) nucleation on the inclusions and precipitates dispersed in austenite (fee γ), denoted as intragranular ferrite transformation, has been used to refine the microstructure in the heat affected zone to improve the toughness of low and medium carbon steels. It is currently considered that Bl(NaCl)-type complex inclusions/precipitates (e.g. oxide, sulfide, carbide, nitride) are promising ones as ferrite nucleation sites. The present study aims to study the ability of various complex inclusions/precipitates in austenite as nucleation sites in proeutectoid ferrite transformations by standard and analytical electron microscopy.
Table 1 shows the chemical composition of Fe-2Mn-0.2C hypoeutectoid steels with various alloying element additions to change the inclusions/precipitate in austenite. Steel A contains a large density of MnS with the sulfur addition of 470ppm. Steels B and C also contain similar dispersion of MnS as Steel A.
Phase Stability in Cast HP Austenite After Long-Term Ageing
Authors: Kenik EA , Maziasz PJ 
Published: July 2020

Abstract
Casting of high temperature austenitic alloys is often used to form components and structures required in the chemical industry. Alloy HP is a Nb-stabilized austenitic alloy for such applications. High carbon levels are selected in order to drive the formation of coarse, intergranular precipitates of various carbides. These precipitates provide resistance to high temperature creep by inhibiting grain boundary sliding. While these precipitates are present in the cast material prior to high temperature exposure, it is the stability of these second phase particles during ageing that determines the long-term creep resistance and lifetime of stressed components. This study deals with the phase distribution in a centrifugally-cast HP component from a steam superheater tube in a styrene furnace, which experienced temperatures from 927°C to 1066°C or more for over 105,000 h.
TEM of Phase Transitions in Tridymite and Cristobalite Based Materials.
Authors: Tendeloo Gustaaf Van 
Published: July 2020

Abstract
We have determined the structure of the paraelectric phase of BaAl2O4, which is a stuffed tridymite, by different TEM techniques and we will describe the phase transition between the ferroelectric room temperature phase and the paraelectric high temperature phase. We have also obtained HREM images of the higly radiation sensitive acristobalite phase of (Si0,9 Ge0,1)O2 and analysed the extended defects in this material.
The stuffed tridymite BaAl2O4 is ferroelectric at room temperature and undergoes a paraelectric-ferroelectric (PEFE) phase transition. The transition is reversible, takes place over a wide temperature range (400K-670K) and has a dynamical character. BaAl2O4 is easily obtained by solid state reaction of BaCO3, and A12O4,. The stoichiometric amounts of the initial reagents were mixed, grinded in an agate mortar under acetone and pressed into a pellet. The pellet was annealed in alumina crucibles at 1000 °C and 1300 °C for 40 h in air and furnace cooled.
Characterization of Interphase Interfaces Developed During the Ordering Transformation (ε (A3) →τ (L10)) In Manganese-Aluminum Alloys
Authors: Yanar C , Wiezorek JMK , Radmilovic V , Soffa WA 
Published: July 2020

Abstract
Alloys based on the ferromagnetic τ-phase, which may be established in the Mn-Al system for near equiatomic composition [1], exhibit high magnetocrystalline anisotropy and coercivity and are of interest for advanced permanent magnet applications [2], Their technologically important properties depend strongly on the microstructure and defect structure development associated with the transformation from the disordered hexagonal (A3) ε-phase to the ordered tetragonal (L10) τ-phase. The structure, morphology and chemistry of the (ε/τ) interphase interfaces have been studied by methods of optical and electron microscopy (OM, SEM and TEM) in order to determine the nature of this technically important and scientifically interesting phase transformation. The optimization of processing-property relationships for this class of ferromagnetic materials requires a detailed understanding of the mechanisms facilitating the ordering process.
The τ-phase nucleates at prior ε-grain boundaries (ε-GB) and exhibits a serrated, faceted growth morphology (FIG. l).
TEM Analysis of Corrosion Products From a Radioactive Stainless Steel-based Alloy
Authors: Dietz NL , Keiser DD 
Published: July 2020

Abstract
Argonne National Laboratory has developed an electrometallurgical treatment process for metallic spent nuclear fuel from the Experimental Breeder Reactor-II. This process stabilizes metallic sodium and separates usable uranium from fission products and transuranic elements that are contained in the fuel. The fission products and other waste constituents are placed into two waste forms: a ceramic waste form that contains the transuranic elements and active fission products such as Cs, Sr, I and the rare earth elements, and a metal alloy waste form composed primarily of stainless steel (SS), from claddings hulls and reactor hardware, and ∼15 wt.% Zr (from the U-Zr and U-Pu-Zr alloy fuels). The metal waste form (MWF) also contains noble metal fission products (Tc, Nb, Ru, Rh, Te, Ag, Pd, Mo) and minor amounts of actinides. Both waste forms are intended for eventual disposal in a geologic repository.
Migrating Interfaces in Sapphire Bicrystals and Tricrystals
Authors: Ravishankar N , Johnson MT , Barry Carter C 
Published: July 2020

Abstract
The migration of grain boundaries in polycrystalline materials can occur under a variety of driving forces. Grain growth in a single-phase material and Ostwald ripening of a second phase are two common processes involving boundary migration. The mass transport in each of these cases can be related to a chemical potential difference across the grains; due to curvature in the former case and due to a difference in the chemistry in the latter case. The mass transport across grains controls the densification process during sintering. In the case of liquid-phase sintering (LPS), a liquid film may be present at the grain boundaries which results in an enhanced mass transport between grains leading to faster densification. Hence, in LPS, it is important to understand mass transport across and along a boundary containing a liquid film. The use of bicrystals and tricrystals with glass layers in the boundary can provide a controlled geometry by which to study this phenomenon.
Twinning Mlcrostructure and Charge Ordering in the Colossal Magnetoresistive Manganite Nd1/2Sr1/2MnO3
Authors: Luo Z P , Miller D J , Mitchell J F 
Published: July 2020

Abstract
Charge ordering (C.O.) in the colossal magnetoresistive (CMR) manganites gives rise to an insulating, high-resistance state. This charge ordered state can be melted into a low-resistance metallic-like state by the application of magnetic field. Thus, the potential to attain high values of magnetoresistance with the application of small magnetic fields may be aided by a better understanding of the charge-ordering phenomenon. This study focused on microstructural characterization in Nd1/2Sr1/2MnO3. In Nd1/2Sr1/2MnO3, the nominal valence of Mn is 3.5+. On cooling, charge can localize and lead to a charge ordering between Mn 3+ and Mn 4+. The ordering of charge results in a superlattice structure and a reduction in symmetry.
Thin foil specimens were prepared from bulk samples by conventional thinning and ion milling (at LN2 temperature) methods. The TEM work was carried out in a Philips CM30 at 300 kV with a Gatan LN2 cold stage, and a JEM 4000EX with a resolution of 0.17 nm at 400 kV for HREM observation.
Grain Boundaries and Interfaces in MoSi2 and MoSi2-SiC Composites and Their Effect on High Temperature Strength
Authors: Bailey GW , McKernan S , Price RL , Walck SD , Charest P-M , Gauvin R , Mitra R , Chiou W-A , Venugopal Rao A 
Published: July 2020

Abstract
Molybdenum di-silicides (MoSi2) based materials have a strong potential for high temperature structural applications due to high melting point of 2030°C, outstanding elevated temperature oxidation resistance and limited ductility above a temperature range of 1100-1300°C. The major shortcomings of MoSi2 for structural applications are its poor room temperature fracture toughness and low high temperature strength. Sustained efforts including reinforcing MoSi2 with ceramic reinforcements, alloying and in-situ processing, have been made to improve these properties. The purity of grain boundaries and interfaces, which in turn depends on the processing method plays a significant role in the high temperature properties and this paper aims to show that.
Intimately mixed Mo and Si powders (Mo:Si = 63:37 by weight fraction) were reaction hot pressed (“RHP“) in vacuum at 1500°C for 1 h, using a pressure of 26 MPa. During the hot pressing process, Mo and Si reacted to form MoSi2.
XTEM Study of the Microstructure of PZT Thin Films
Authors: Wang S X , Wang L M , Lin C L 
Published: July 2020

Abstract
Lead zirconate titanate (PbZrxTil-xO3, PZT) is one of the important ferroelectric materials for the storage elements of high-speed non-volatile memories. It also has much potential to be used in pyroelectric sensor, ultrasonic motor, and multiplayer ceramic capacitor.
PZT (Zr/Ti = 48/52) thin films were prepared using a metal-organic decomposition (MOD) process. The precursor solution used for PZT thin film preparation was based on lead acetate trihydrate, Pb(CH3COO)2; zirconium nitrate, Zr(NO3)4.5H2O; and titanium nbutoxide, Ti(nC2H9)4. 2-butoxyethanol was chosen as a solvent. A 30% excess Pb was added to the precursor to compensate for the loss of lead oxide during the annealing process. Acetic acid was used as a complexing agent for PZT solution to control the hydrolysis and condensation rates. The 0.3M precursor solution was spin-coated on the Pt(111)/Ti/SiO2/Si substrates for 20s at 3000 rpm. The deposited film was fired at 450 °C for 10 min and repeated five times to burn out the organics. The films were crystallized at 600 °C in air for 1 hr.